bluuebunny/crossref_metadata_2025 huggingface dataset:
Fault Detection and Isolation of Nonlinear Systems: An Unknown Input Observer Approach With Sum-of-Squares Techniques
Authors: Xu Jun , Lum Kai-Yew , Xie Lihua , Loh Ai-Poh
Published: April 2012

This paper presents a novel nonlinear unknown input observer (UIO) design method for fault detection and isolation (FDI) of a class of nonlinear affine systems. By using sum-of-squares (SOS) theory and Lie geometry as the main tools, we demonstrate how to relax the rank constraint in the traditional UIO approach and simplify the design procedure, especially for the polynomial nonlinear systems. Meanwhile, we show that the detection and isolation thresholds based on the L2 gains can be easily obtained via optimization formulated in terms of SOS. Simulation examples are given to illustrate the design procedure and the advantages.
Semiglobal Stabilization for Nonholonomic Mobile Robots Based on Dynamic Feedback With Inputs Saturation
Authors: Chen Hua , Wang Chaoli , Yang Liu , Zhang Dongkai
Published: April 2012

This paper investigates the semiglobal stabilization problem for nonholonomic mobile robots based on dynamic feedback with inputs saturation. A bounded, continuous, time-varying controller is presented such that the closed-loop system is semiglobally asymptotically stable. The systematic strategy combines finite-time control technique with the virtual-controller-tracked method, which is similar to the back-stepping procedure. First, the bound-constrained smooth controller is presented for the kinematic model. Second, the dynamic feedback controller is designed to make the generalized velocity converge to the prespecified kinematic (virtual) controller in a finite time. Furthermore, the rigorous proof is given for the stability analysis of the closed-loop system. In the mean time, the position and torque inputs of robots are proved to be bounded at any time. Finally, the simulation results show the effectiveness of the proposed control approach.
Optimal Energy Use in a Light Weight Hydraulic Hybrid Passenger Vehicle
Authors: Deppen Timothy O. , Alleyne Andrew G. , Stelson Kim A. , Meyer Jonathan J.
Published: April 2012

In this study we present a procedure for the design and implementation of a control strategy to optimize energy use within a light weight hydraulic hybrid passenger vehicle. The hydraulic hybrid utilizes a high pressure accumulator for energy storage which has superior power density than conventional battery technology. This makes fluid power attractive for urban driving applications in which there are frequent starts and stops and large startup power demands. A dynamic model of a series hydraulic hybrid powertrain is presented along with the design of a model predictive control based energy management strategy. Model predictive control was chosen for this study because it uses no future information about the drive cycle in its design. This increases the flexibility of the controller allowing it to be directly applied to a variety of drive cycles. Using the model predictive framework, a holistic view of the powertrain was taken in the design of the control strategy, and the impact of each actuator’s efficiency on overall efficiency was evaluated. A hardware-in-the-loop experiment using an electro-hydraulic powertrain testbed was then used to validate the dynamic model and control performance. Through a simulation study in which each actuator’s efficiency was given varying levels of priority in the objective function, it was found that overall system efficiency could be improved by allowing for small sacrifices in individual component performance. In fact, the conventional wisdom of using the additional degrees of freedom within a hybrid powertrain to optimize engine efficiency was found to yield the lowest overall powertrain efficiency. In this work we present a rigorous framework for the design of an energy management strategy. The design method improves the powertrain’s operational efficiency by finding the best balance between optimizing individual component efficiencies. Furthermore, since the design of the control strategy is built upon an analysis of individual components, it can be readily extended to other architectures employing different actuators.
Frontiers in the Constitutive Modeling of Anisotropic Shock Waves
Authors: Lukyanov Alexander A. , Segletes Steven B.
Published: April 2012

Studies of anisotropic materials and the discovery of various novel and unexpected phenomena under shock loading has contributed significantly to our understanding of the behavior of condensed matter. The variety of experimental studies for isotropic materials displays systematic patterns, giving basic insights into the underlying physics of anisotropic shock wave modeling. There are many similarities and significant differences in the phenomena observed for isotropic and anisotropic materials under shock-wave loading. Despite this, the anisotropic constitutive equations must represent mathematical and physical generalization of the conventional constitutive equations for isotropic material and reduce to the conventional constitutive equations in the limit of isotropy. This article presents the current state of the art in the constitutive modeling of this fascinating field.
Conceptual Design Method for Reducing Brake Squeal in Disk Brake Systems Considering Unpredictable Usage Factors
Authors: Matsushima Toru , Izui Kazuhiro , Nishiwaki Shinji
Published: April 2012

Minimizing brake squeal is one of the most important issues in the development of high performance braking systems. Furthermore, brake squeal occurs due to the changes in unpredictable factors such as the friction coefficient, contact stiffness, and pressure distribution along the contact surfaces of the brake disk and brake pads. This paper proposes a conceptual design method for disk brake systems that specifically aims to reduce the occurrence of low frequency brake squeal at frequencies below 5 kHz by appropriately modifying the shapes of brake system components to obtain designs that are robust against changes in the above unpredictable factors. A design example is provided and the validity of the obtained optimal solutions is then verified through real-world experiments. The proposed optimization method can provide useful design information at the conceptual design stage during the development of robust disk brake systems that maximize the performance while minimizing the occurrence of brake squeal despite the presence of unpredictable usage factors.
Improved CO Tolerance With PtRu Anode Catalysts in ABPBI Based High Temperature Proton Exchange Membrane Fuel Cells
Authors: Oettel Christian , Rihko-Struckmann Liisa , Sundmacher Kai
Published: April 2012

The potential to improve the CO tolerance of a high temperature proton exchange membrane fuel cell (HT-PEMFC) was investigated by introducing a platinum-ruthenium alloy as anode catalyst. The electrolyte was a H3PO4 doped poly-2,5-benzimidazole polymer (ABPBI). The experiments were carried out at the temperatures between 403 and 443 K with a CO concentration in the H2 feed gas between 0 and 6.5 vol%. The alloy anode catalyst lowers significantly the negative influence of CO in the feed, exceeding the known temperature dependent CO poisoning mitigation in HT-PEMFCs. It was found that the voltage loss of a HT-PEMFC with PtRu anode catalyst was lower than that of a similar cell equipped with Pt anode. The dynamic cell voltage response to a current step was analyzed under CO influence, as well. The PtRu bimetallic anode electrode was found to lower the observed voltage overshoot behavior after a current step, if compared to conventional Pt anode.
Synthesis of patterned nanographene on insulators from focused ion beam induced deposition of carbon
Authors: Rius Gemma , Yoshimura Masamichi , Mestres Narcis
Published: April 2012

A unique approach was used to synthesize nanographene directly on insulating substrates with precise positioning control. The process is comprised of two steps: (i) deposition of carbon using focused ion beam induced deposition and (ii) annealing in vacuum at mid-high temperatures using metal foil as the catalyst material. The characteristics of the carbon nanomaterial can be specified in terms of morphology, shape, thickness, and crystalline size. Ion beam induced deposition allows the definition of 3D features with submicron resolution and pattern flexibility. Metal-assisted annealing transforms the as-deposited amorphous C into nanographene, as confirmed by Raman spectroscopy.
Neural Correlates of a Magnetic Sense
Authors: Wu Le-Qing , Dickman J. David
Published: April 2012

Magnetic Sense

Many species orient and navigate using aspects of Earth's magnetic field. Magnetic receptors have been found in the eyes, ears, and bills of birds, but there has been no clear evidence of the neural mechanism by which magnetic signals are translated into direction. Recording from the brainstem within conscious pigeons,
Wu and Dickman
(p.
1054
, published online 26 April; see the Perspective by

Winklhofer

) reveal the presence of neurons in the pigeon's brain that encode the inclination angle and intensity of the geomagnetic field. Thus, pigeons—and perhaps other species—can develop an internal model of geopositional latitude to facilitate spatial orientation and navigation based on magnetoreception.
Evolutionary Trade-Offs, Pareto Optimality, and the Geometry of Phenotype Space
Authors: Shoval O. , Sheftel H. , Shinar G. , Hart Y. , Ramote O. , Mayo A. , Dekel E. , Kavanagh K. , Alon U.
Published: April 2012

Managing Trade-Offs

Most organisms experience selection on a host of traits to determine their likelihood to succeed evolutionarily. However, specific traits may experience trade-offs in determining an organism's optimal phenotype.

Shoval
et al.

(p.
1157
; see the Perspective by

Noor and Milo

) relate physical traits to the task that they are optimizing using a Pareto curve, a power law probability distribution, to show that a single set of trait values optimizes performance at a given task and that performance decreases as an organism's phenotype moves away from this set of trait values. The results suggest how selection makes the best trade-offs for an arbitrary number of tasks and traits and may explain examples of evolutionary variation.
Performance of Two Commercially Available Automated Immunoassays for the Determination of Epstein-Barr Virus Serological Status
Authors: Lupo J. , Germi R. , Semenova T. , Buisson M. , Seigneurin J. M. , Morand P.
Published: April 2012

This study evaluated the performance of two automated Vidas (V) and Liaison (L) immunoassays for Epstein-Barr virus (EBV) serology. The detection of the viral capsid antigen (VCA) IgM, the VCA/early antigen (VCA/EA) IgG, and the Epstein-Barr nuclear antigen (EBNA) IgG was assessed on 526 sera collected for routine EBV testing in immunocompetent subjects. The determination of expected EBV status (186 EBV primary infections, 183 past EBV infections, and 157 EBV-seronegative individuals) was based on results of routine laboratory enzyme immunoassays (EIAs) together with clinical data. The sensitivity and specificity of each individual marker were determined in comparison to the expected EBV status. The agreement between the V and L profiles and the expected EBV status was established through the interpretation of combinations of the different EBV markers. Statistically significant differences between the two tests were found for the specificity of the VCA IgM marker (96.2% for V versus 93.2% for L), the sensitivity of the VCA/EA IgG marker (89% for V versus 94% for L), and the specificity of the EBNA IgG marker (96.5% for V versus 74.2% for L). The results determined for the two assays with respect to overall agreement with the established expected EBV status were not significantly different (89.7% for V versus 88.2% for L), with discrepancies mainly observed in sera referenced as primary infections. These findings demonstrated the similar performances of the Vidas and the Liaison assays for the establishment of an EBV serological status using the VCA, EA, and EBNA markers.
Reassessment of Immune Correlates in Human Visceral Leishmaniasis as Defined by Cytokine Release in Whole Blood
Authors: Singh Om Prakash , Gidwani Kamlesh , Kumar Rajiv , Nylén Susanne , Jones Stephen L. , Boelaert Marleen , Sacks David , Sundar Shyam
Published: April 2012

Depressed cell-mediated immunity in human visceral leishmaniasis (VL) (also known as kala-azar), revealed as the inability of peripheral blood mononuclear cells (PBMCs) to respond toLeishmaniaantigen, remains a hallmark of and is thought to underlie the progressive nature of this disease. We recently reported the ability of a whole-blood, gamma interferon (IFN-γ) release assay to detect subclinical infections among healthy individuals living in an area where kala-azar is endemic (Bihar, India) and the surprising result that patients with active VL also secreted significant levels of antigen-specific IFN-γ in this assay. We were interested in ascertaining whether these findings would be true for a larger cohort of subjects and in employing the whole-blood assay to detect additional cytokines that might better correlate with the disease status of infected individuals. We evaluated IFN-γ, tumor necrosis factor alpha (TNF-α), and interleukin-10 (IL-10) release in 35 patients with active VL, 54 patients with VL who were cured, 27 patients with other diseases, 52 healthy controls who lived in regions where VL or kala-azar is not endemic (NEHCs [for nonendemic healthy controls]), and 147 healthy controls who lived in regions where kala-azar is endemic (EHCs [for endemic healthy controls]). The cellular responses of the EHCs were correlated with their serological antibody titers againstLeishmania donovaniandPhlebotomus argentipessaliva. The whole-blood cells from the majority of both active (80%) and cured (85%) VL patients, as well as 24% of EHCs with presumed subclinical infections, produced significantly elevated levels of IFN-γ. The findings do not support a severe Th1 response defect in kala-azar. Importantly, only the patients with active VL also produced IL-10, which in conjunction with IFN-γ better reflects the immune responses that distinguish individuals with active disease from cured or subclinically infected, immune individuals.
Comparative Analysis of the Humoral Immune Response to Moraxella catarrhalis and Streptococcus pneumoniae Surface Antigens in Children Suffering from Recurrent Acute Otitis Media and Chronic Otitis Media with Effusion
Authors: Verhaegh Suzanne J. C. , Stol Kim , de Vogel Corné P. , Riesbeck Kristian , Lafontaine Eric R. , Murphy Timothy F. , van Belkum Alex , Hermans Peter W. M. , Hays John P.
Published: April 2012

A prospective clinical cohort study was established to investigate the humoral immune response in middle ear fluids (MEF) and serum against bacterial surface proteins in children suffering from recurrent acute otitis media (rAOM) and chronic otitis media with effusion (COME), using Luminex xMAP technology. The association between the humoral immune response and the presence of
Moraxella catarrhalis
and
Streptococcus pneumoniae
in the nasopharynx and middle ear was also studied. The levels of antigen-specific IgG, IgA, and IgM showed extensive interindividual variation. No significant differences in anti-
M. catarrhalis
and anti-
S. pneumoniae
serum and MEF median fluorescence intensity (MFI) values (anti-
M. catarrhalis
and antipneumococcal IgG levels) were observed between the rAOM or COME groups for all antigens tested. No significant differences were observed for
M. catarrhalis
and
S. pneumoniae
colonization and serum IgG levels against the
Moraxella
and pneumococcal antigens. Similar to the antibody response in serum, no significant differences in IgG, IgA, and IgM levels in MEF were observed for all
M. catarrhalis
and
S. pneumoniae
antigens between OM
M. catarrhalis-
or
S. pneumoniae
-positive and OM
M. catarrhalis-
or
S. pneumonia
-negative children suffering from either rAOM or COME. Finally, results indicated a strong correlation between antigen-specific serum and MEF IgG levels. We observed no significant
in vivo
expressed anti-
M. catarrhalis
or anti-
S. pneumoniae
humoral immune responses using a range of putative vaccine candidate proteins. Other factors, such as Eustachian tube dysfunction, viral load, and genetic and environmental factors, may play a more important role in the pathogenesis of OM and in particular in the development of rAOM or COME.
PspA Family Distribution, unlike Capsular Serotype, Remains Unaltered following Introduction of the Heptavalent Pneumococcal Conjugate Vaccine
Authors: Croney Christina M. , Coats Mamie T. , Nahm Moon H. , Briles David E. , Crain Marilyn J.
Published: April 2012

Pneumococcal conjugate vaccines (PCVs) are recommended for the prevention of invasive pneumococcal disease (IPD) in young children. Since the introduction of the heptavalent pneumococcal vaccine (PCV7) in 2000, IPD caused by serotypes in the vaccine has almost been eliminated, and previously uncommon capsular serotypes now cause most cases of pediatric IPD in the United States. One way to protect against these strains would be to add cross-reactive protein antigens to new vaccines. One such protein is pneumococcal surface protein A (PspA). Prior to 2000, PspA families 1 and 2 were expressed by 94% of isolates. Because PCV7 vaccine pressure has resulted in IPD caused by capsular serotypes that were previously uncommon and unstudied for PspA expression, it was possible that many of the new strains expressed different PspA antigens or even lacked PspA. Of 157 pediatric invasive pneumococcal isolates collected at a large pediatric hospital in Alabama between 2002 and 2010, only 60.5% had capsular serotypes included in PCV13, which came into general use in Alabama after our strains were collected. These isolates included 17 serotypes that were not covered by PCV13. Nonetheless, pneumococcal capsular serotype replacement was not associated with changes in PspA expression; 96% of strains in this collection expressed PspA family 1 or 2. Continued surveillance will be critical to vaccine strategies to further reduce IPD.
Does Tetanus-Diphtheria-Acellular Pertussis Vaccination Interfere with Serodiagnosis of Pertussis Infection?
Authors: Pawloski Lucia C. , Kirkland Kathryn B. , Baughman Andrew L. , Martin Monte D. , Talbot Elizabeth A. , Messonnier Nancy E. , Tondella Maria Lucia
Published: April 2012

An anti-pertussis toxin (PT) IgG enzyme-linked immunosorbent assay (ELISA) was analytically validated for the diagnosis of pertussis at a cutoff of 94 ELISA units (EU)/ml. Little was known about the performance of this ELISA in the diagnosis of adults recently vaccinated with tetanus-diphtheria-acellular pertussis (Tdap) vaccine, which contains PT. The goal of this study was to determine when the assay can be used following Tdap vaccination. A cohort of 102 asymptomatic health care personnel (HCP) vaccinated with Tdap (Adacel; Sanofi Pasteur) were aged 19 to 79 years (median, 47 years) at vaccination. For each HCP, specimens were available for evaluation at 2 to 10 time points (prevaccination to 24 months postvaccination), and geometric mean concentrations (GMC) for the cohort were calculated at each time point. Among 97 HCP who responded to vaccination, a mixed-model analysis with prediction and tolerance intervals was performed to estimate the time at which serodiagnosis can be used following vaccination. The GMCs were 8, 21, and 9 EU/ml at prevaccination and 4 and 12 months postvaccination, respectively. Eight (8%) of the 102 HCP reached antibody titers of ≥94 EU/ml during their peak response, but none had these titers by 6 months postvaccination. The calculated prediction and tolerance intervals were <94 EU/ml by 45 and 75 days postvaccination, respectively. Tdap vaccination 6 months prior to testing did not confound result interpretation. This seroassay remains a valuable diagnostic tool for adult pertussis.
Draft Genome Sequence of Daldinia eschscholzii Isolated from Blood Culture
Authors: Ng Kee Peng , Ngeow Yun Fong , Yew Su Mei , Hassan Hamimah , Soo-Hoo Tuck Soon , Na Shiang Ling , Chan Chai Ling , Hoh Chee-Choong , Lee Kok-Wei , Yee Wai-Yan
Published: April 2012

Daldinia eschscholzii
is an invasive endophyte that is most commonly found in plant tissues rich in secondary metabolites. We report the draft genome sequence of
D. eschscholzii
isolated from blood culture. The draft genome is 35,494,957 bp in length, with 42,898,665 reads, 61,449 contigs, and a G+C content of 46.8%. The genome was found to contain a high abundance of genes associated with plant cell wall degradation enzymes, mycotoxin production, and antifungal drug resistance.
Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Caspofungin Susceptibility Testing of Candida and Aspergillus Species
Authors: De Carolis Elena , Vella Antonietta , Florio Ada R. , Posteraro Patrizia , Perlin David S. , Sanguinetti Maurizio , Posteraro Brunella
Published: April 2012

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) was evaluated for testing susceptibility to caspofungin of wild-type and
fks
mutant isolates of
Candida
and
Aspergillus
. Complete essential agreement was observed with the CLSI reference method, with categorical agreement for 94.1% of the
Candida
isolates tested. Thus, MALDI-TOF MS is a reliable and accurate method to detect fungal isolates with reduced caspofungin susceptibility.
Accurate Identification of Candida parapsilosis (Sensu Lato) by Use of Mitochondrial DNA and Real-Time PCR
Authors: Souza Ana Carolina R. , Ferreira Renata C. , Gonçalves Sarah S. , Quindós Guillermo , Eraso Elena , Bizerra Fernando C. , Briones Marcelo R. S. , Colombo Arnaldo L.
Published: April 2012

Candida parapsilosis
is the
Candida
species isolated the second most frequently from blood cultures in South America and some European countries, such as Spain. Since 2005, this species has been considered a complex of 3 closely related species:
C. parapsilosis
,
Candida metapsilosis
, and
Candida orthopsilosis
. Here, we describe a real-time TaqMan-MGB PCR assay, using mitochondrial DNA (mtDNA) as the target, which readily distinguishes these 3 species. We first used comparative genomics to locate syntenic regions between these 3 mitochondrial genomes and then selected
NADH5
as the target for the real-time PCR assay. Probes were designed to include a combination of different single-nucleotide polymorphisms that are able to differentiate each species within the
C. parapsilosis
complex. This new methodology was first tested using mtDNA and then genomic DNA from 4 reference and 5 clinical strains. For assay validation, a total of 96 clinical isolates and 4 American Type Culture Collection (ATCC) isolates previously identified by internal transcribed spacer (
ITS
) ribosomal DNA (rDNA) sequencing were tested. Real-time PCR using genomic DNA was able to differentiate the 3 species with 100% accuracy. No amplification was observed when DNA from other species was used as the template. We observed 100% congruence with
ITS
rDNA sequencing identification, including for 30 strains used in blind testing. This novel method allows a quick and accurate intracomplex identification of
C. parapsilosis
and saves time compared with sequencing, which so far has been considered the “gold standard” for
Candida
yeast identification. In addition, this assay provides a useful tool for epidemiological and clinical studies of these emergent species.
Development and Validation of a Semiquantitative, Multitarget PCR Assay for Diagnosis of Bacterial Vaginosis
Authors: Cartwright Charles P. , Lembke Bryndon D. , Ramachandran Kalpana , Body Barbara A. , Nye Melinda B. , Rivers Charles A. , Schwebke Jane R.
Published: April 2012

Quantitative PCR assays were developed for 4 organisms reported previously to be useful positive indicators for the diagnosis of bacterial vaginosis (BV)—
Atopobium vaginae
, Bacterial Vaginosis-Associated Bacterium 2 (BVAB-2),
Gardnerella vaginalis
, and
Megasphaera-
1—and a single organism (
Lactobacillus crispatus
) that has been implicated as a negative indicator for BV. Vaginal samples (
n
= 169), classified as positive (
n
= 108) or negative (
n
= 61) for BV based on a combination of the Nugent Gram stain score and Amsel clinical criteria, were analyzed for the presence and quantity of each of the marker organisms, and the results were used to construct a semiquantitative, multiplex PCR assay for BV based on detection of 3 positive indicator organisms (
A. vaginae
, BVAB-2, and
Megasphaera
-1) and classification of samples using a combinatorial scoring system. The prototype BV PCR assay was then used to analyze the 169-member developmental sample set and, in a prospective, blinded manner, an additional 227 BV-classified vaginal samples (110 BV-positive samples and 117 BV-negative samples). The BV PCR assay demonstrated a sensitivity of 96.7% (202/209), a specificity of 92.2% (153/166), a positive predictive value of 94.0%, and a negative predictive value of 95.6%, with 21 samples (5.3%) classified as indeterminate for BV. This assay provides a reproducible and objective means of evaluating critical components of the vaginal microflora in women with signs and symptoms of vaginitis and is comparable in diagnostic accuracy to the conventional gold standard for diagnosis of BV.
Seronegative Hepatitis C Virus Infection in a Child Infected via Mother-to-Child Transmission
Authors: Larouche Ariane , Gaëtan Geneviève , El-Bilali Nabil , Quesnel-Vallières Mathieu , Martin Steven R. , Alvarez Fernando , Shoukry Naglaa H. , Soudeyns Hugo
Published: April 2012

Hepatitis C virus (HCV) infection typically leads to antibody response within weeks after primary infection. Here, we describe the case of a child infected with HCV by mother-to-child transmission who remained persistently seronegative despite the presence of high levels of circulating HCV RNA.
Comparison of Three Roche Hepatitis B Virus Viral Load Assay Formats
Authors: Pyne Michael T. , Vest Lauren , Clement Jennifer , Lee Jessica , Rosvall Jessica R. , Luk Kevin , Rossi Michael , Cobb Bryan , Hillyard David R.
Published: April 2012

Two FDA-approved (
in vitro
diagnostic [IVD]) hepatitis B virus (HBV) viral load assays, the manual Cobas TaqMan HBV Test for use with the High Pure System (HP) and the automated Cobas AmpliPrep/Cobas TaqMan HBV Test v2.0 (CAP/CTM), were compared to a modified (not FDA-approved) version of the HP assay by automating the DNA extraction using the Total Nucleic Acid Isolation (TNAI) kit on the Cobas AmpliPrep. On average, CAP/CTM measurements were 0.08 log IU/ml higher than HP results (
n
= 206), and TNAI results were 0.17 log IU/ml higher than HP results (
n
= 166). The limit of detection (LOD), as determined by probit analysis using dilutions of the 2nd HBV international standard, was 10.2 IU/ml for CAP/CTM. The data sets for HP and TNAI were insufficient for probit analysis; however, there was 100% detection at ≥5 or ≥10 IU/ml for TNAI and HP, respectively. Linearity was demonstrated between 60 and 2,000,000 IU/ml, with slopes between 0.95 and 0.99 and
R
2
values of >0.99 for all assays. Total precision (log percent coefficient of variance [CV]) was between 0.8% and 2.1% at 4.3 log IU/ml and between 1.4% and 4.9% at 2.3 log IU/ml. Correlation of samples, reproducibility, linearity, and LOD were acceptable and similar in all assays. The CAP/CTM assay and, to a lesser extent, the TNAI assay reduced hands-on time due to automation. There were no instances of contamination detected in negative samples during the course of the study, despite testing several samples up to 9.6 log IU/ml. The incidence of false-positive negative controls in HP and CAP/CTM clinical testing was <0.5% over 6 to 7 months of testing.
Comparison of Dimethyl Sulfoxide and Water as Solvents for Echinocandin Susceptibility Testing by the EUCAST Methodology
Authors: Alastruey-Izquierdo Ana , Gómez-López Alicia , Arendrup Maiken C. , Lass-Florl Cornelia , Hope William W. , Perlin David S. , Rodriguez-Tudela Juan L. , Cuenca-Estrella Manuel
Published: April 2012

Ninety-six strains of
Candida
, including 29 resistant and 67 susceptible isolates with mutations in the
FKS1
and
FKS2
genes were tested by the European Committee on Antibiotic Susceptibility Testing EDef 7.1 and 7.2 methodologies to determine the impact on the MIC when water was replaced with dimethyl sulfoxide (DMSO) as the solvent for caspofungin and micafungin. The MICs were significantly lower and the MIC ranges were narrower when DMSO was used as the solvent. The use of DMSO may help to better discriminate between susceptible and resistant populations.
Head, neck, and brain tumor embolization guidelines
Authors: Duffis E Jesus , Gandhi Chirag D , Prestigiacomo Charles Joseph , Abruzzo Todd , Albuquerque Felipe , Bulsara Ketan R , Derdeyn Colin P , Fraser Justin F , Hirsch Joshua A , Hussain Muhammad Shazam , Do Huy M , Jayaraman Mahesh V , Meyers Philip M , Narayanan Sandra
Published: April 2012

Background

Management of vascular tumors of the head, neck, and brain is often complex and requires a multidisciplinary approach. Peri-operative embolization of vascular tumors may help to reduce intra-operative bleeding and operative times and have thus become an integral part of the management of these tumors. Advances in catheter and non-catheter based techniques in conjunction with the growing field of neurointerventional surgery is likely to expand the number of peri-operative embolizations performed. The goal of this article is to provide consensus reporting standards and guidelines for embolization treatment of vascular head, neck, and brain tumors.

This article was produced by a writing group comprised of members of the Society of Neurointerventional Surgery. A computerized literature search using the National Library of Medicine database (Pubmed) was conducted for relevant articles published between 1 January 1990 and 31 December 2010. The article summarizes the effectiveness and safety of peri-operative vascular tumor embolization. In addition, this document provides consensus definitions and reporting standards as well as guidelines not intended to represent the standard of care, but rather to provide uniformity in subsequent trials and studies involving embolization of vascular head and neck as well as brain tumors.

Conclusions

Peri-operative embolization of vascular head, neck, and brain tumors is an effective and safe adjuvant to surgical resection. Major complications reported in the literature are rare when these procedures are performed by operators with appropriate training and knowledge of the relevant vascular and surgical anatomy. These standards may help to standardize reporting and publication in future studies.
Fishing power and standardized catch rates: implications of missing vessel-characteristic data from the Australian eastern king prawn (Melicertus plebejus) fishery
Authors: Braccini J.M. , O’Neill M.F. , Campbell A.B. , Leigh G.M. , Courtney A.J.
Published: April 2012

Standardized time series of fishery catch rates require collations of fishing power data on vessel characteristics. Linear mixed models were used to quantify fishing power trends and study the effect of missing data encountered when relying on commercial logbooks. For this, Australian eastern king prawn ( Melicertus plebejus ) harvests were analysed with historical (from vessel surveys) and current (from commercial logbooks) vessel data. Between 1989 and 2010, fishing power increased up to 76%. To date, both forward-filling and, alternatively, omitting records with missing vessel information from commercial logbooks produce broadly similar fishing power increases and standardized catch rates, owing to the strong influence of years with complete vessel data (16 out of 23 years of data). However, if gaps in vessel information had not originated randomly and skippers from the most efficient vessels were the most diligent at filling in logbooks, considerable errors would be introduced. Also, the buffering effect of complete years would be short-lived as years with missing data accumulate. Given ongoing changes in fleet profile with high-catching vessels fishing proportionately more of the fleet’s effort, compliance with logbook completion, or alternatively ongoing vessel gear surveys, is required for generating accurate estimates of fishing power and standardized catch rates.
Will environmental calcium declines hinderBythotrephesestablishment success in Canadian Shield lakes?
Authors: Kim Natalie , Walseng Bjørn , Yan Norman David
Published: April 2012

Recently, calcium-rich daphniids have declined on the Canadian Shield in response to falling lake-water calcium concentrations, or [Ca]. Meanwhile the invader Bythotrephes longimanus , a predator that feeds on Daphnia , continues to spread. Our goal was to determine if ongoing calcium declines might directly or indirectly affect Bythotrephes ’ establishment success. To address direct effects, we provide the first quantification of Bythotrephes’ calcium content, which is very low (0.03% as dry mass) compared with other Cladocera. We also examined the effects of differing [Ca] (0.1–2.6 mg·L–1) on Bythotrephes’ performance in the laboratory. For all [Ca], population growth rates remained positive, indicating that Bythotrephes has great tolerance of low [Ca]. Finally, we examined Bythotrephes’ distribution in relation to [Ca] on the Shield where is it relatively new, alongside its distribution in Norway where it is endemic and found that Bythotrephes inhabits very low calcium environments in Norway (minimum = 0.2 mg·L–1). These results suggest that Bythotrephes establishment in Canada is currently not — and in the future will likely not — be limited by falling calcium. Rather, as Bythotrephes is more tolerant of low [Ca] than are its daphniid prey, we propose that both calcium decline and Bythotrephes invasions may contribute to Daphnia decline.
Unravelling the effects of water temperature and density dependence on the spatial variation of brown trout (Salmo trutta) body size
Authors: Parra Irene , Almodóvar Ana , Ayllón Daniel , Nicola Graciela G. , Elvira Benigno
Published: April 2012

This study looks at the relative influence of water temperature and density dependence on the spatial variation in body size of 126 brown trout ( Salmo trutta ) cohorts from 12 Iberian rivers over a 12-year period. Mean cohort mass and length of age groups 0+ to 2+ varied significantly among sampling sites because of the concurrent effect of water temperature and density dependence. Density in suitable habitat had a limiting role that influenced potential maximum growth of cohorts, and water temperature differentiated these cohorts in two groups of sites with high and low potential maximum growth. Water temperature had a positive cumulative effect on body size of all age classes. However, body size of age-0 trout was nonlinearly influenced by short-term exposure to extreme water temperature. Thus, extremely high temperatures became a limiting factor and had deleterious effects on growth. There were intracohort and intercohort effects of density dependence throughout the life span, which were mainly due to the density in the available suitable habitat of trout of the same age or older. The present study supports the hypothesis that both density-dependent and density-independent processes are crucial for the understanding of population dynamics and that their relative importance varies across scales of space and time.
The influence of population dynamics and environmental conditions on pink salmon (Oncorhynchus gorbuscha) recolonization after barrier removal in the Fraser River, British Columbia, Canada
Authors: Pess G.R. , Hilborn R. , Kloehn K. , Quinn T.P.
Published: April 2012

When barriers are removed, what biotic and abiotic factors determine how fish populations will colonize newly available habitats? We used counts of adult pink salmon ( Oncorhywnchus gorbuscha ) from 1947 to 1987 in 66 streams of the Fraser River system, British Columbia, Canada, to determine when colonizing pink salmon populations became self-sustaining after a long-term migration blockage at Hell’s Gate (river kilometre 209) was reduced. The abundance of salmon in available habitats were largely controlled by extrinsic factors such as an initially large source population, high intrinsic growth rates linked to favorable climate-driven conditions, a constant supply of dispersers, and large amounts of newly available habitat. Temporal variation in flows at Hell’s Gate also affected recolonization success. Self-sustaining populations were developed within years of barrier removal and have continued to help expand the overall population of Fraser River pink salmon. However, pink salmon were considerably more abundant in the early 1900s than in the 1980s (∼48 million vs. ∼2.7 million), and the majority of spawning shifted from the historic areas above Hell’s Gate prior to the rockslide to below Hell’s Gate in the lower Fraser River after the long-term blockage was reduced, so the system has not returned to the former abundance and distribution patterns.
Use of a marine reserve to determine the direct and indirect effects of fishing on growth in a New Zealand fishery for the spiny lobster Jasus edwardsii
Authors: Freeman Debbie J. , Breen Paul A. , MacDiarmid Alison B.
Published: April 2012

The effects of fishing on growth in a spiny lobster, Jasus edwardsii , were explored by using a no-take marine reserve as a control for these effects. We analysed data from lobster tag–recapture studies outside the reserve from 1975 until the present and tag–recapture from inside the reserve during a recent 8-year study. We explored whether recent and historical data showed similar growth and, using catch per unit effort (CPUE) data from research potting and commercial returns, whether growth rates in this lobster species were affected by population density. Despite the confounded nature of the data, recent growth rates appeared to be lower than in earlier years, growth appeared weakly density-dependent, and the reserve appeared to have a positive effect on lobster growth. The strongest effect was the time period, but the density-dependent and reserve effects appeared real. The reserve effect suggests a negative effect of handling of sublegal-sized lobsters on growth.
Critical swim speed and fast-start response in the African cichlidPseudocrenilabrus multicolor victoriae: convergent performance in divergent oxygen regimes
Authors: Gotanda K.M. , Reardon E.E. , Murphy S.M.C. , Chapman L.J.
Published: April 2012

Dissolved oxygen (DO) can be a strong predictor of intraspecific variation in morphology and physiology in fishes. In the African cichlid Pseudocrenilabrus multicolor victoriae Seegers, 1990, fish reared under low DO develop larger gills, deeper bodies, and larger, wider heads than full siblings reared under high DO, which could influence swim performance. In this study, we compared critical swim speed (Ucrit) and fast-start swimming in F1-generation fish from two field populations (one high and one low DO) of P. m. victoriae reared under high or low DO. There was no difference in Ucritbetween populations or rearing treatments. However, females exhibited a lower Ucritthan males. In fast-start trials, low-DO-reared fish reacted faster (lower response latency) and used double bends more often than high-DO-reared fish, but there was no difference in maximum velocity or acceleration. Low-DO-reared fish might compensate for morphological differences by using double bends to achieve similar performance as high-DO siblings. These results suggest that divergent morphotypes of P. m. victoriae are capable of achieving the same level of performance under their home DO condition and highlights the importance of developmental plasticity in facilitating adaptive response to alternative environments.
The cybrid invasion: widespread postglacial dispersal byPhoxinus(Pisces: Cyprinidae) cytoplasmic hybrids
Authors: Mee J.A. , Taylor E.B.
Published: April 2012

Peculiar reproductive processes that arise during sperm-dependent asexual reproduction may have important roles in allowing coexistence of sperm-dependent asexuals and their sexually reproducing hosts. Though typically clonal, nonclonal reproduction in the hybrid gynogenetic species Phoxinus eos–neogaeus can reestablish sexual northern redbelly dace ( Phoxinus eos (Cope, 1861)) nuclear genomes. These hybrid-derived P. eos biotypes, known as cybrids, have finescale dace ( Phoxinus neogaeus Cope, 1867) mitochondria but are otherwise indistinguishable from “pure” P. eos. Our goal was to determine the extent of the cybrids’ distribution, and hence to evaluate their role in mechanisms of asexual–sexual coexistence. We also set out to determine the geographic origins of P. eos–neogaeus and cybrids. Our sampling revealed that all Phoxinus species and biotypes are widely distributed in North America, but that cybrids have replaced pure P. eos, or preempted postglacial colonization by pure P. eos, in the northern portion of their distribution. Also, all P. eos–neogaeus and cybrids had mitochondrial DNA (mtDNA) sequences closely related to a lineage originating from a Mississippi glacial refugium. No P. eos–neogaeus or cybrids were derived from a divergent P. neogaeus lineage discovered in Atlantic Canada. It is therefore unlikely that P. eos–neogaeus or cybrids originated in any Atlantic glacial refugia. If P. neogaeus mitochondria are better adapted to northern environments, widespread mtDNA introgression may facilitate coexistence in northern areas by reducing the disparity in fitness between P. eos–neogaeus and its sexual hosts.
Population subdivision and peripheral isolation in American badgers (Taxidea taxus) and implications for conservation planning in Canada
Authors: Ethier D.M. , Laflèche A. , Swanson B.J. , Nocera J.J. , Kyle C.J.
Published: April 2012

In Canada, three subspecies of American badgers ( Taxidea taxus (Schreber, 1777)) traditionally are identified; two of which are listed as endangered because of their restricted geographic range and low population sizes. To verify their subspecific designations and genetic insularity, we analyzed mitochondrial control region sequences within and among badger subspecies ( Taxidea taxus jacksoni Schantz, 1946, Taxidea taxus jeffersonii (Harlan, 1825), and Taxidea taxus taxus (Schreber, 1777)) from nine locations in Canada and bordering United States. Although subspecies designations were supported (a priori subspecific designations, n = 3, AMOVA: FST = 0.40, p < 0.001), insular populations also were found within subspecific ranges as shown by spatial analysis of molecular variation, which suggested that our sample set consisted of five genetic groups (FST = 0.39, p < 0.001). These five distinct groupings included the subdivision of T. t. jeffersonii on either side of the Selkirk Mountains, and of T. t. jacksoni in the western part of its range grouping more closely with T. t. taxus of Manitoba. These results indicate that endangered populations of badgers may be more segregated than previously identified using morphological characteristics as proxies for subspecific designation. These results have important implications for the conservation of badgers in Canada, particularly of the two endangered subspecies.
Frugivory by Taiwan Barbets (Megalaima nuchalis) and the effects of deinhibition and scarification on seed germination
Authors: Chang Sing-Yi , Lee Ya-Fu , Kuo Yen-Min , Chen Jia-Huei
Published: April 2012

We investigated the frugivory of Taiwan Barbets ( Megalaima nuchalis Gould, 1863) on passage time and germination of 19 species of commonly consumed fruits, distinguished the deinhibition and scarification effects, and tested if complete bird-gut passage increases seed germination. We measured fruit and seed size and seed retention times (SRTs) and examined the germination of intact fruits and pulp-removed and defecated seeds. Germination latency in intact fruits of most species was prolonged, whereas in more non-figs (7/12), the seed germinability increased after ingestion, and nearly all figs germinated by higher proportions after defecation or depulping. Yet, figs revealed major differences from non-figs. SRTs of both non-figs and figs were negatively dependent on fruit size, which was positively correlated to seed size in non-figs only. The germinability was negatively correlated and the germination onset time was positively correlated with SRTs of the last seeds in non-figs, but neither was correlated with SRTs in figs. Most (14/17) species with germination success were enhanced either by deinhibition and scarification, or the fruits hardly germinated but were aided by pulp removal. Deinhibition revealed greater effects than scarification in increasing the germinability and shortening latency, thus aiding, in particular, non-fig seeds with shorter SRTs or that are often culled during feeding.
Effects of male ejaculate on female reproductive output and longevity in Photinus fireflies
Authors: South A. , Lewis S.M.
Published: April 2012

In many insects, nuptial gifts in the form of spermatophores have been shown to increase female fecundity and to contribute to female somatic maintenance. Examining how variation in male spermatophore size affects female fitness components can provide insight into the evolution of nuptial gifts, as well as insight into potential conflicts between the sexes. Here we present an experimental study on the firefly Photinus obscurellus LeConte, 1851 in which we altered spermatophore size by manipulating male mating history and examined effects on female offspring production and longevity. Females were randomly allocated to one of two mating treatments in which they mated once with a male producing either a large or a small spermatophore. We found that male spermatophore size had no significant effect on lifetime fecundity or daily reproductive rates of female P. obscurellus, but females that received a larger spermatophore showed a tendency toward longer postmating life spans. These results suggest a direct benefit to females from nuptial gifts and also reveal the potential for synergistic effects on multiple facets of female fitness.
TOPOLOGICAL STABILITY OF BROKEN SYMMETRY ON FUZZY SPHERES
Authors: DIGAL S. , GOVINDARAJAN T. R.
Published: April 2012

We study the spontaneous symmetry breaking of O(3) scalar field on a fuzzy sphere [Formula: see text]. We find that the fluctuations in the background of topological configurations are finite. This is in contrast to the fluctuations around a uniform configuration which diverge, due to Mermin–Wagner–Hohenberg–Coleman theorem, leading to the decay of the condensate. Interesting implications of enhanced topological stability of the configurations are pointed out.
DARK ENERGY DENSITY IN MODELS WITH SPLIT SUPERSYMMETRY AND DEGENERATE VACUA
Authors: FROGGATT C. , NEVZOROV R. , NIELSEN H. B.
Published: April 2012

In N = 1 supergravity supersymmetric and nonsupersymmetric Minkowski vacua originating in the hidden sector can be degenerate. In the supersymmetric phase in flat Minkowski space, nonperturbative supersymmetry breakdown may take place in the observable sector, inducing a nonzero and positive vacuum energy density. Assuming that such a supersymmetric phase and the phase in which we live are degenerate, we estimate the value of the cosmological constant. We argue that the observed value of the dark energy density can be reproduced in the split SUSY scenario of SUSY breaking if the SUSY breaking scale is of order of 1010 GeV.
PRIME KNOTS WHOSE ARC INDEX IS SMALLER THAN THE CROSSING NUMBER
Authors: JIN GYO TAEK , LEE HWA JEONG
Published: April 2012

It is known that the arc index of alternating knots is the minimal crossing number plus two and the arc index of prime nonalternating knots is less than or equal to the minimal crossing number. We study some cases when the arc index is strictly less than the minimal crossing number. We also give minimal grid diagrams of some prime nonalternating knots with 13 crossings and 14 crossings whose arc index is the minimal crossing number minus one.