bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermomechanical Transient Analysis and Conceptual Optimization of a First Stage Bucket
Authors: Campos-Amezcua Alfonso , Mazur-Czerwiec Zdzislaw , Gallegos-Muñoz Armando
Published: September 2010

This paper presents a thermomechanical analysis of a first stage bucket during a gas turbine startup. This analysis uses two simulation techniques, computational fluid dynamics (CFD) for the conjugate heat transfer and flow analysis, and finite element analysis (FEA) for the thermostructural analysis. Computational three-dimensional models were developed using two commercial codes, including all elements of the real bucket to avoid geometric simplifications. An interface was developed to transfer the three-dimensional behavior of bucket temperatures during turbine startup from CFD analysis to subsequent FEA analysis, imposing them as a thermal load. This interface virtually integrates the computational models, although they have different grids. The results of this analysis include temperature evolution and related stresses, as well as the thermomechanical stresses and zones where they are present. These stresses are dominated by thermal mechanisms, so a new temperature startup curve is proposed where the maximum calculated stress decline around 100 MPa, and almost all stresses are lower throughout the transient analysis. The results are compared with experimental data reported in the literature obtaining acceptable approximation.
Effects of nanoscale Ni, Al, and Ni–Al interlayers on nucleation and growth of diamond on Si
Authors: Li Y. S. , Tang Y. , Yang Q. , Hirose A.
Published: September 2010

Diamond nucleation experiments on Si wafers, precoated with Ni, Al, and Ni–Al duplex intermediate layers, have been conducted in a microwave plasma enhanced chemical vapor deposition reactor. The diamond nucleation density is dependent on the thickness of the single Ni interlayer and also the ratio of Ni/Al. The diamond nucleation density increases with the Ni thickness up to approximately 100 nm. Above 100 nm, decrease in the nucleation density is observed. The nondiamond carbon concentration increases when the Ni thickness increases from 40 to 200 nm, along with a simultaneous increase of nondiamond carbon accumulation on the Si substrate surface. The diamond grown on Si with an Al interlayer is of high purity but of low nucleation density. For the Ni–Al duplex interlayer, increase of Al fraction enhances both the purity and nucleation density of diamond, and markedly reduces the formation of nondiamond carbon on the Si substrate surfaces.
Signaling from the Endoplasmic Reticulum Activates Brassinosteroid Signaling and Promotes Acclimation to Stress in
Arabidopsis
Authors: Che Ping , Bussell John D. , Zhou Wenxu , Estavillo Gonzalo M. , Pogson Barry J. , Smith Steven M.
Published: September 2010

BR signaling may integrate stress responses and growth processes to optimize growth under challenging environmental conditions.
Exit by Exosome
Authors: Wong Wei
Published: September 2010

Two tetraspanins reduce β-catenin–dependent signaling by promoting the extracellular release of this signaling protein in exosomes.
Optimizing Population Dispersal
Authors: VanHook Annalisa M.
Published: September 2010

Pheromones regulate olfactory plasticity in nematodes.
Mr. Blebby
Authors: Hurtley Stella M.
Published: September 2010

Altering the homeostasis of membrane-bound signaling molecules allows a bacterial pathogen to corrupt cell function.
Discriminating Dendrites
Authors: Stern Peter R.
Published: September 2010

Dendrites of neurons are sensitive to the sequence of synaptic activation and can implement cortical computation.
Differentiation between Polymorphisms and Resistance-Associated Mutations in Human Cytomegalovirus DNA Polymerase
Authors: Chevillotte Meike , Ersing Ina , Mertens Thomas , von Einem Jens
Published: September 2010

Specific mutations in the human cytomegalovirus (HCMV) DNA polymerase (pUL54) are known to confer resistance against all currently licensed drugs for treatment of HCMV infection and disease. Following the widespread use of antivirals, the occurrence of HCMV drug resistance is constantly increasing. Recently, diagnostic laboratories have started to replace phenotypic drug resistance testing with genotypic resistance testing. However, the reliability and success of genotypic testing highly depend on the availability of high-quality phenotypic resistance data for each individual mutation and for combinations of mutations, with the latter being increasingly found in patients' HCMV isolates. We performed clonal marker transfer experiments to investigate the impacts of 7 different UL54 point mutations and also of combinations of these mutations on drug susceptibility and viral replicative fitness. We show that several mutations—S695T, A972V, K415R, S291P, and A692V—of suspected but uncertain drug susceptibility phenotype, either alone or in combination, were not relevant to antiviral drug resistance. In contrast, the combination of two mutations individually characterized previously—E756K and D413E—conferred high-grade loss of susceptibility to all three antivirals. Our results have been added to the newly available database of all published HCMV resistance mutations (http://www.informatik.uni-ulm.de/ni/mitarbeiter/HKestler/hcmv/index.html). These data will allow better interpretation of genotypic data and further improve the basis for drug resistance testing.
Total Raltegravir Concentrations in Cerebrospinal Fluid Exceed the 50-Percent Inhibitory Concentration for Wild-Type HIV-1
Authors: Croteau David , Letendre Scott , Best Brookie M. , Ellis Ronald J. , Breidinger Sheila , Clifford David , Collier Ann , Gelman Benjamin , Marra Christina , Mbeo Gilbert , McCutchan Allen , Morgello Susan , Simpson David , Way Lauren , Vaida Florin , Ueland Susan , Capparelli Edmund , Grant Igor
Published: September 2010

HIV-associated neurocognitive disorders continue to be common. Antiretrovirals that achieve higher concentrations in cerebrospinal fluid (CSF) are associated with better control of HIV and improved cognition. The objective of this study was to measure total raltegravir (RAL) concentrations in CSF and to compare them with matched concentrations in plasma and
in vitro
inhibitory concentrations. Eighteen subjects with HIV-1 infection were enrolled based on the use of RAL-containing regimens and the availability of CSF and matched plasma samples. RAL was measured in 21 CSF and plasma pairs by liquid chromatography-tandem mass spectrometry, and HIV RNA was detected by reverse transcription-PCR (RT-PCR). RAL concentrations were compared to the 50% inhibitory concentration (IC
50
) for wild-type HIV-1 (3.2 ng/ml). Volunteers were predominantly middle-aged white men with AIDS and without hepatitis C virus (HCV) coinfection. The median concurrent CD4
+
cell count was 276/μl, and 28% of CD4
+
cell counts were below 200/μl. HIV RNA was detectable in 38% of plasma specimens and 4% of CSF specimens. RAL was present in all CSF specimens, with a median total concentration of 14.5 ng/ml. The median concentration in plasma was 260.9 ng/ml, with a median CSF-to-plasma ratio of 0.058. Concentrations in CSF correlated with those in with plasma (
r
2
, 0.24;
P
, 0.02) but not with the postdose sampling time (
P
, >0.50). RAL concentrations in CSF exceeded the IC
50
for wild-type HIV in all specimens by a median of 4.5-fold. RAL is present in CSF and reaches sufficiently high concentrations to inhibit wild-type HIV in all individuals. As a component of effective antiretroviral regimens or as the main antiretroviral, RAL likely contributes to the control of HIV replication in the nervous system.
Interplay between Drug Efflux and Antioxidants in
Escherichia coli
Resistance to Antibiotics
Authors: Dhamdhere Girija , Krishnamoorthy Ganesh , Zgurskaya Helen I.
Published: September 2010

We investigated possible cross talk between endogenous antioxidants glutathione, spermidine, and glutathionylspermidine and drug efflux in
Escherichia coli
. We found that cells lacking either spermidine or glutathione are less susceptible than the wild type to novobiocin and certain aminoglycosides. In contrast, exogenous glutathione protects against both bactericidal and bacteriostatic antibiotics. The glutathione protection does not require the AcrAB efflux pump but fails in cells lacking TolC because exogenous glutathione is toxic to these cells.
In Vitro
Activity of Pyronaridine against Multidrug-Resistant
Plasmodium falciparum
and
Plasmodium vivax
Authors: Price R. N. , Marfurt J. , Chalfein F. , Kenangalem E. , Piera K. A. , Tjitra E. , Anstey N. M. , Russell B.
Published: September 2010

Pyronaridine, a Mannich base antimalarial, has demonstrated high
in vivo
and
in vitro
efficacy against chloroquine-resistant
Plasmodium falciparum
. Although this drug has the potential to become a prominent artemisinin combination therapy, little is known about its efficacy against drug-resistant
Plasmodium vivax
. The
in vitro
antimalarial susceptibility of pyronaridine was assessed in multidrug-resistant
P. vivax
(
n
= 99) and
P. falciparum
(
n
= 90) isolates from Papua, Indonesia, using a schizont maturation assay. The median 50% inhibitory concentration (IC
50
) of pyronaridine was 1.92 nM (range, 0.24 to 13.8 nM) against
P. falciparum
and 2.58 nM (range, 0.13 to 43.6 nM) against
P. vivax
, with
in vitro
susceptibility correlating significantly with chloroquine, amodiaquine, and piperaquine (

r
s

[Spearman's rank correlation coefficient] = 0.45 to 0.62;
P
< 0.001).
P. falciparum
parasites initially at trophozoite stage had higher IC
50
s of pyronaridine than those exposed at the ring stage (8.9 nM [range, 0.6 to 8.9 nM] versus 1.6 nM [range, 0.6 to 8.9 nM], respectively;
P
= 0.015), although this did not reach significance for
P. vivax
(4.7 nM [range, 1.4 to 18.7 nM] versus 2.5 nM [range, 1.4 to 15.6 nM], respectively;
P
= 0.085). The excellent
in vitro
efficacy of pyronaridine against both chloroquine-resistant
P. vivax
and
P. falciparum
highlights the suitability of the drug as a novel partner for artemisinin-based combination therapy in regions where the two species are coendemic.
Successful Treatment of Vancomycin-Intermediate
Staphylococcus aureus
Pacemaker Lead Infective Endocarditis with Telavancin
Authors: Marcos Luis A. , Camins Bernard C.
Published: September 2010

Emerging infections caused by vancomycin-intermediate
Staphylococcus aureus
(VISA) isolates are more likely to be associated with treatment failures than infections caused by other types of
S. aureus
. We present a case of pacemaker lead infective endocarditis caused by a non-daptomycin-susceptible strain of VISA. After 8 weeks of parenteral telavancin therapy, the patient achieved microbiological and clinical cure.
Potent Synergy and Sustained Bactericidal Activity of a Vancomycin-Colistin Combination versus Multidrug-Resistant Strains of
Acinetobacter baumannii
Authors: Gordon N. C. , Png K. , Wareham D. W.
Published: September 2010

Multidrug-resistant
Acinetobacter baumannii
(MDRAB) presents an increasing challenge to health care. Although colistin has been used as a treatment of last resort, there is concern regarding its potential for toxicity and the emergence of resistance. The mechanism of action of colistin, however, raises the possibility of synergy with compounds that are normally inactive against Gram-negative organisms by virtue of the impermeability of the bacterial outer membrane. This study evaluated the effect of colistin combined with vancomycin on 5 previously characterized epidemic strains and 34 MDRAB clinical isolates by using time-kill assay, microdilution, and Etest methods. For all the isolates, significant synergy was demonstrated by at least one method, with reductions in the MIC of vancomycin from >256 μg/ml to ≤48 μg/ml for all strains after exposure to 0.5 μg/ml colistin. This raises the possibility of the clinical use of this combination for infections due to MDRAB, with the potential for doses lower than those currently used.
In VitroCharacterization of the Microglial Inflammatory Response toStreptococcus suis, an Important Emerging Zoonotic Agent of Meningitis
Authors: Domínguez-Punaro María de la Cruz , Segura Mariela , Contreras Irazú , Lachance Claude , Houde Mathieu , Lecours Marie-Pier , Olivier Martin , Gottschalk Marcelo
Published: September 2010

Streptococcus suisis an important swine and human pathogen responsible for septicemia and meningitis.In vivoresearch in mice suggested that in the brain, microglia might be involved in activating the inflammatory response againstS. suis. The aim of this study was to better understand the interactions betweenS. suisand microglia. Murine microglial cells were infected with a virulent wild-type strain ofS. suis. Two isogenic mutants deficient at either capsular polysaccharide (CPS) or hemolysin production were also included. CPS contributed toS. suisresistance to phagocytosis and regulated the inflammatory response by hiding proinflammatory components from the bacterial cell wall, while the absence of hemolysin, a potential cytotoxic factor, did not have a major impact onS. suisinteractions with microglia. Wild-typeS. suisinduced enhanced expression of Toll-like receptor 2 by microglial cells, as well as phophotyrosine, protein kinase C, and different mitogen-activated protein kinase signaling events. However, cells infected with the CPS-deficient mutant showed overall stronger and more sustained phosphorylation profiles. CPS also modulated inducible nitric oxide synthase expression and further nitric oxide production fromS. suis-infected microglia. Finally,S. suis-induced NF-κB translocation was faster for cells stimulated with the CPS-deficient mutant, suggesting that bacterial cell wall components are potent inducers of NF-κB. These results contribute to increase the knowledge of mechanisms underlyingS. suisinflammation in the brain and will be useful in designing more efficient anti-inflammatory strategies for meningitis.
Violence at the workplace increases the risk of musculoskeletal pain among nursing home workers
Authors: Miranda Helena , Punnett Laura , Gore Rebecca , Boyer Jon
Published: September 2010

Background

Despite the high prevalences of workplace physical violence and musculoskeletal symptoms among health care workers, very few studies have examined the relationship between these two phenomena.

Methods

We surveyed 920 clinical nursing home workers by questionnaire regarding musculoskeletal pain in the low back, shoulders, wrists or hands, and knees. Information was also collected on exposure to physical assaults at work during the preceding 3 months, other workplace safety features, physical workload and psychosocial work environment. Log-binomial regression was used to estimate the prevalence ratios (PR) with 95% CIs.

Results

Almost one-half of respondents reported being assaulted at least once during the preceding 3 months by a resident or resident's visitor. The prevalence of low back pain increased from 40% among non-assaulted workers to 70% among those assaulted three or more times. The highest risk was found for widespread pain (three or more areas), with an adjusted PR of 2.7 (95% CI 1.8 to 3.9) for workers assaulted three or more times. Good workplace safety buffered the effects, so that violence increased the risk of most pains considerably less in a work environment perceived to be safe.

Conclusions

To our knowledge, this is the first study to show a dose–response association between physical assaults and musculoskeletal pain in a health care setting where violence is a frequent occurrence. This emphasises the need to address violence as a workplace hazard through practical measures for prevention as well as in future aetiological research on musculoskeletal disorders.
The role of obesity and lifestyle behaviours in a productive workforce
Authors: Robroek Suzan J W , van den Berg Tilja I J , Plat Jan F , Burdorf Alex
Published: September 2010

Objectives

This study aims to investigate the role of lifestyle factors in relation to the presence and degree of productivity loss at work and sick leave.

Methods

A cross-sectional study recruited 10 624 workers in 49 companies in the Netherlands in 2005–2009. Productivity loss at work was measured on a 10-point scale indicating how much work was actually performed on the previous workday. Sick leave was measured by asking how many days in the past 12 months workers were off work due to health problems. Logistic regression analyses were applied to study the association between obesity and lifestyle behaviours and both outcome measures.

Results

Obesity was associated with the presence of sick leave (OR 1.25) and prolonged duration (OR 1.55). Insufficient physical activity (OR 1.12) and smoking (OR 1.17) were also associated with the presence of sick leave. Smoking (OR 1.45), obesity (OR 1.29) and insufficient fruit and vegetable intake (OR 1.22) were associated with the degree of productivity loss at work. The combined population attributable fractions of lifestyle factors for sick leave and the higher levels of productivity loss at work were above 10%.

Conclusions

Lifestyle-related factors, especially smoking and obesity, were associated with the presence and duration of sick leave and degree of productivity loss at work. More than 10% of sick leave and the higher levels of productivity loss at work may be attributed to lifestyle behaviours and obesity. Hence, primary interventions on lifestyle may have a noticeable contribution to maintaining a productive workforce.
Mesoarchaean to Palaeoproterozoic growth of the northern segment of the Itabuna–Salvador–Curaçá orogen, São Francisco craton, Brazil
Authors: Oliveira E. P. , McNaughton N. J. , Armstrong R.
Published: September 2010

The geology of the northern segment of the Itabuna–Salvador–Curaçá orogen, São Francisco craton, is reviewed, and new U–Pb ages, and Nd isotope and major and trace element data are combined to improve understanding of its tectonic evolution. The results indicate that oceanic crust and island arc sequences accreted at about 3.30 Ga to form the Mundo Novo greenstone belt, and between 2.15 and 2.12 Ga to form the Rio Itapicuru and Rio Capim greenstone belts. At about 3.08–2.98 Ga, mafic crust underwent partial melting to form the Retirolândia and Jacurici tonalite–trondhjemite–granodiorite belts of the Serrinha block. From 2.69 to 2.58 Ga an Andean-type arc with ocean crust remnants formed the Caraiba complex possibly at the Gavião block margin. Between 2.11 and 2.105 Ga, the Rio Itapicuru arc collided with the Retirolândia–Jacurici microcontinent, possibly involving slab breakoff. Oblique convergence between 2.09 and 2.07 Ga led to collision of the Serrinha microcontinent with the Caraíba–Gavião superblock and reworked the Caraíba arc to granulites, locally at ultrahigh-temperature conditions. At the same time, arc dacites spread over the Rio Itapicuru greenstone belt, and the 3.12–3.0 Ga Uauá terrane, crosscut by 2.58 Ga mafic dykes, extruded from south to north, possibly together with the 2.15 Ga Rio Capim greenstone belt.
Ocean plate stratigraphy and its imbrication in an accretionary orogen: the Mona Complex, Anglesey–Lleyn, Wales, UK
Authors: Maruyama S. , Kawai T. , Windley B. F.
Published: September 2010

We re-evaluate the Neoproterozoic, Pacific-type accretionary complex on Anglesey and in the Lleyn peninsula (Wales, UK), by reconstructing its ocean plate stratigraphy (OPS). Three types of distinctive OPS were successively emplaced downwards in an accretionary wedge: the oldest at the top formed when an ocean opened and closed from a ridge to a trench, the central OPS was subjected to deep subduction and exhumed as blueschists, and the youngest at the bottom is an olistostrome-type deposit that formed by secondary gravitational collapse of previously accreted material. The three types formed by successive eastward subduction of young oceanic lithosphere at the leading edge of Avalonia. The downward growth of the accretionary complex through time was almost coeval with exhumation of the blueschist unit at 550–560 Ma in the structural centre of the complex on Anglesey. From balanced sections we have reconstructed the ocean plate stratigraphy on Llanddwyn Island from which we calculate that about 8 km of lateral shortening of ocean floor took place during imbrication and accretion; this is comparable with the history of plate subduction around the Pacific Ocean. We also calculate that the age of the subducted lithosphere was very young, probably less than 10 Ma.
Petrology, chemistry and phase relations of borosilicate phases in phlogopite diopsidites and granitic pegmatites from the Tranomaro belt, SE Madagascar; boron-fluid evolution
Authors: Razakamanana Théodore , Windley Brian F. , Ackermand Dietrich
Published: September 2010

The boron-bearing minerals grandidierite, werdingite, serendibite and sinhalite are common in high-grade rocks of the Tranomaro belt in southeastern Madagascar. The mutual occurrence of these phases allows a new understanding of the role of boron-rich fluids in the crustal evolution of Gondwana, and we provide critical borosilicate data to constrain that development. We distinguish two types of grandidierite depending on their B
2
O
3
and Al
2
O
3
contents and on their relations with associated borosilicate phases. (1) At Vohibola the presence of sinhalite and serendibite associated with phlogopite lenses in metasedimentary diopsidites indicates an evaporitic origin from calc-silicate sediments. (2) At Cape Andrahomana borosilicates are associated with pegmatites and granites that were emplaced along shear zones on the boundary of the Tranomaro belt. The shear zones acted as conduits for boron-bearing fluids and for granitic partial melts, which had derived their boron from calc-silicate sedimentary protoliths. Using geothermometry and geobarometry of minerals from associated rocks, we calculate that ambient pressures and temperatures changed in time from 7.5 to 4.0 kbar and from
c
. 800 °C to 700 °C. Our results confirm the important role of shear zones in channelling the fluid flow of boron-bearing fluids that were derived from crustal melt granites in the same shear zones, but that ultimately derived their boron from early metasediments. We provide new information on the mineralogy, phase assemblages and paragenetic history of multiple borosilicates.
Reconstruction and interpretation of giant mafic dyke swarms: a case study of 1.78 Ga magmatism in the North China craton
Authors: Peng Peng
Published: September 2010

Short-lived giant mafic dyke swarms are keys to the interpretation of continental evolution and tectonics, reconstruction of continental palaeogeographical regimes, and petrogenesis of volcanism. The 1.78 Ga Taihang–Lvliang dyke swarm, one of the most significant and best-preserved Precambrian swarms in the central part of the North China craton (NCC), is reviewed and discussed. It is interpreted to have a radiating geometry that is compatible with the Xiong'er triple-junction rift, in which the Xiong'er volcanic province is proposed to be the extrusive counterpart of this swarm. It resulted in significant extension, uplift and magmatic accretion of the NCC, and it is comparable with the Phanerozoic large igneous provinces (LIPs) in areal extent (
c.
0.3 Mkm
2
) and estimated volume (
c.
0.3 Mkm
3
), short lifespan (<20 Ma), and intraplate setting. This North China LIP is unique in that it comprises large volumes of both mafic and intermediate components. It could have resulted from extensive mantle–crust interaction, probably driven by a large-scale mantle upwelling. A plume tectonic model is favoured by several lines of supporting evidence (i.e. massive volcanic flows correlated over large areas and a giant fanning dyke swarm with plume-affinitive chemistry). It could responsible for massive sulphide (Pb–Zn) and gold (Au–Ag) ore deposits in the Xiong'er volcanic province. Dismembered remnants of this magmatism in other block(s), with potential candidates in South America, Australia and India, could identify other cratonic blocks that were formerly connected to the North China craton.
MLD2P4
Authors: D’Ambra Pasqua , Serafino Daniela Di , Filippone Salvatore
Published: September 2010

Domain decomposition ideas have long been an essential tool for the solution of PDEs on parallel computers. In recent years many research efforts have been focused on recursively employing domain decomposition methods to obtain multilevel preconditioners to be used with Krylov solvers. In this context, we developed MLD2P4 (MultiLevel Domain Decomposition Parallel Preconditioners Package based on PSBLAS), a package of parallel multilevel preconditioners that combines additive Schwarz domain decomposition methods with a smoothed aggregation technique to build a hierarchy of coarse-level corrections in an algebraic way. The design of MLD2P4 was guided by objectives such as extensibility, flexibility, performance, portability, and ease of use. They were achieved by following an object-based approach while using the Fortran 95 language, as well as by employing the PSBLAS library as a basic framework. In this article, we present MLD2P4 focusing on its design principles, software architecture, and use.
Parallel Solvers for Sylvester-Type Matrix Equations with Applications in Condition Estimation, Part I
Authors: Granat Robert , Kågström Bo
Published: September 2010

Parallel ScaLAPACK-style algorithms for solving eight common standard and generalized Sylvester-type matrix equations and various sign and transposed variants are presented. All algorithms are blocked variants based on the Bartels--Stewart method and involve four major steps: reduction to triangular form, updating the right-hand side with respect to the reduction, computing the solution to the reduced triangular problem, and transforming the solution back to the original coordinate system. Novel parallel algorithms for solving reduced triangular matrix equations based on wavefront-like traversal of the right-hand side matrices are presented together with a generic scalability analysis. These algorithms are used in condition estimation and new robust parallel sep
 − 1
-estimators are developed. Experimental results from three parallel platforms, including results from a mixed OpenMP/MPI platform, are presented and analyzed using several performance and accuracy metrics. The analysis includes results regarding general and triangular parallel solvers as well as parallel condition estimators.
Algorithm 906
Authors: Li Tiancheng , Robinson Ian
Published: September 2010

A three-dimensional automatic cubature routine, calledelrint3d, is described and numerical results are presented that demonstrate its applicability across a wide range of domains and integrand types. The underlying algorithm is based on a 2s-copy lattice augmentation sequence, the seed lattice for which has been determined by exhaustive search based on optimization of index of merit and trigonometric degree of precision.
Algorithm 907
Authors: Davis Timothy A. , Palamadai Natarajan Ekanathan
Published: September 2010

KLU is a software package for solving sparse unsymmetric linear systems of equations that arise in circuit simulation applications. It relies on a permutation to Block Triangular Form (BTF), several methods for finding a fill-reducing ordering (variants of approximate minimum degree and nested dissection), and Gilbert/Peierls’ sparse left-looking LU factorization algorithm to factorize each block. The package is written in C and includes a MATLAB interface. Performance results comparing KLU with SuperLU, Sparse 1.3, and UMFPACK on circuit simulation matrices are presented. KLU is the default sparse direct solver in the Xyce
TM
circuit simulation package developed by Sandia National Laboratories.
An Interoperable, Data-Structure-Neutral Component for Mesh Query and Manipulation
Authors: Ollivier-Gooch Carl , Diachin Lori , Shephard Mark S. , Tautges Timothy , Kraftcheck Jason , Leung Vitus , Luo Xiaojuan , Miller Mark
Published: September 2010

Much of the effort required to create a new simulation code goes into developing infrastructure for mesh data manipulation, adaptive refinement, design optimization, and so forth. This infrastructure is an obvious target for code reuse, except that implementations of these functionalities are typically tied to specific data structures. In this article, we describe a software component---an abstract data model and programming interface---designed to provide low-level mesh query and manipulation support for meshing and solution algorithms. The component’s data model provides a data abstraction, completely hiding all details of how mesh data is stored, while its interface defines how applications can interact with that data. Because the component has been carefully designed to be general purpose and efficient, it provides a practical platform for implementing high-level mesh operations independently of the underlying mesh data structures. After describing the data model and interface, we provide several usage examples, each of which has been used successfully with multiple implementations of the interface functionality. The overhead due to accessing mesh data through the interface rather than directly accessing the underlying mesh data is shown to be acceptably small.
Optimizing energy and performance for server-class file system workloads
Authors: Sehgal Priya , Tarasov Vasily , Zadok Erez
Published: September 2010

Recently, power has emerged as a critical factor in designing components of storage systems, especially for power-hungry data centers. While there is some research into power-aware storage stack components, there are no systematic studies evaluating each component's impact separately. Various factors like workloads, hardware configurations, and software configurations impact the performance and energy efficiency of the system. This article evaluates the file system's impact on energy consumption and performance. We studied several popular Linux file systems, with various mount and format options, using the FileBench workload generator to emulate four server workloads: Web, database, mail, and fileserver, on two different hardware configurations. The file system design, implementation, and available features have a significant effect on CPU/disk utilization, and hence on performance and power. We discovered that default file system options are often suboptimal, and even poor. In this article we show that a careful matching of expected workloads and hardware configuration to a single software configuration—the file system—can improve power-performance efficiency by a factor ranging from 1.05 to 9.4 times.
Accurate and Accessible Motion-Capture Glove Calibration for Sign Language Data Collection
Authors: Huenerfauth Matt , Lu Pengfei
Published: September 2010

Motion-capture recordings of sign language are used in research on automatic recognition of sign language or generation of sign language animations, which have accessibility applications for deaf users with low levels of written-language literacy. Motion-capture gloves are used to record the wearer’s handshape. Unfortunately, they require a time-consuming and inexact calibration process each time they are worn. This article describes the design and evaluation of a new calibration protocol for motion-capture gloves, which is designed to make the process more efficient and to be accessible for participants who are deaf and use American Sign Language (ASL). The protocol was evaluated experimentally; deaf ASL signers wore the gloves, were calibrated (using the new protocol and using a calibration routine provided by the glove manufacturer), and were asked to perform sequences of ASL handshapes. Five native ASL signers rated the correctness and understandability of the collected handshape data. In an additional evaluation, ASL signers were asked to perform ASL stories while wearing the gloves and a motion-capture bodysuit (in some cases our new calibration protocol was used, in other cases, the standard protocol). Later, twelve native ASL signers watched animations produced from this motion-capture data and answered comprehension questions about the stories. In both evaluation studies, the new protocol received significantly higher scores than the standard calibration. The protocol has been made freely available online, and it includes directions for the researcher, images and videos of how participants move their hands during the process, and directions for participants (as ASL videos and English text).
Investigating Grid-Based Navigation
Authors: Zhu Shaojian , Feng Jinjuan , Sears Andrew
Published: September 2010

Hands-free speech-based technology can be a useful alternative for individuals that find traditional input devices, such as keyboard and mouse, difficult to use. Various speech-based navigation techniques have been examined, and several are available in commercial software applications. Among these alternatives, grid-based navigation has demonstrated both potential and limitations. In this article, we discuss an empirical study that assessed the efficacy of two enhancements to grid-based navigation: magnification and fine-tuning. The magnification capability enlarges the selected region when it becomes sufficiently small, making it easier to see the target and cursor. The fine-tuning capability allows users to move the cursor short distances to position the cursor over the target. The study involved one group of participants with physical disabilities, an age-matched group of participants without disabilities, and a third group that included young adults without disabilities. The results confirm that both magnification and fine-tuning significantly improved the participants’ performance when selecting targets, especially small targets. Providing either, or both, of the proposed enhancements substantially reduced the gaps in performance due to disability and age. The results will inform the design of speech-based target selection mechanism, allowing users to select targets faster while making fewer errors.
Hardware-Accelerated RNA Secondary-Structure Alignment
Authors: Moscola James , Cytron Ron K. , Cho Young H.
Published: September 2010

The search for homologous RNA molecules---sequences of RNA that might behave simiarly due to similarity in their physical (secondary) structure---is currently a computationally intensive task. Moreover, RNA sequences are populating genome databases at a pace unmatched by gains in standard processor performance. While software tools such as Infernal can efficiently find homologies among RNA families and genome databases of modest size, the continuous advent of new RNA families and the explosive growth in volume of RNA sequences necessitate a faster approach.

This work introduces two different architectures for accelerating the task of finding homologous RNA molecules in a genome database. The first architecture takes advantage of the tree-like configuration of the covariance models used to represent the consensus secondary structure of an RNA family and converts it directly into a highly-pipelined processing engine. Results for this architecture show a 24× speedup over Infernal when processing a small RNA model. It is estimated that the architecture could potentially offer several thousands of times speedup over Infernal on larger models, provided that there are sufficient hardware resources available.

The second architecture is introduced to address the steep resource requirements of the first architecture. It utilizes a uniform array of processing elements and schedules all of the computations required to scan for an RNA homolog onto those processing elements. The estimated speedup for this architecture over the Infernal software package ranges from just under 20× to over 2,350×.
Reducing Memory Constraints in Modulo Scheduling Synthesis for FPGAs
Authors: Ben-Asher Yosi , Meisler Danny , Rotem Nadav
Published: September 2010

In High-Level Synthesis (HLS), extracting parallelism in order to create small and fast circuits is the main advantage of HLS over software execution. Modulo Scheduling (MS) is a technique in which a loop is parallelized by overlapping different parts of successive iterations. This ability to extract parallelism makes MS an attractive synthesis technique for loop acceleration. In this work we consider two problems involved in the use of MS which are central when targeting FPGAs. Current MS scheduling techniques sacrifice execution times in order to meet resource and delay constraints. Let “ideal” execution times be the ones that could have been obtained by MS had we ignored resource and delay constraints. Here we pose the opposite problem, which is more suitable for HLS, namely, how to reduce resource constraints without sacrificing the ideal execution time. We focus on reducing the number of memory ports used by the MS synthesis, which we believe is a crucial resource for HLS. In addition to reducing the number of memory ports we consider the need to develop MS techniques that are fast enough to allow interactive synthesis times and repeated applications of the MS to explore different possibilities of synthesizing the circuits. Current solutions for MS synthesis that can handle memory constraints are too slow to support interactive synthesis. We formalize the problem of reducing the number of parallel memory references in every row of the kernel by a novel combinatorial setting. The proposed technique is based on inserting dummy operations in the kernel and by doing so, performing modulo-shift operations such that the maximal number of parallel memory references in a row is reduced. Experimental results suggest improved execution times for the synthesized circuit. The synthesis takes only a few seconds even for large-size loops.
Bandwidth Management in Application Mapping for Dynamically Reconfigurable Architectures
Authors: Banerjee Sudarshan , Bozorgzadeh Elaheh , Noguera Juanjo , Dutt Nikil
Published: September 2010

Partial dynamic reconfiguration (often referred to as partial RTR) enables true on-demand computing. In an on-demand computing environment, a dynamically invoked application is assigned resources such as data bandwidth, configurable logic. The limited logic resources are customized during application execution by exploiting partial RTR. In this article, we propose an approach that maximizes application performance when available bandwidth and logic resources are limited. Our proposed approach is based on theoretical principles of minimizing application schedule length under bandwidth and logic resource constraints. It includes detailed microarchitectural considerations on a commercially popular reconfigurable device, and it exploits partial RTR very effectively by utilizing data-parallelism property of common image-processing applications. We present extensive application case studies on a cycle-accurate simulation platform that includes detailed resource considerations of the Xilinx Virtex XC2V3000. Our experimental results demonstrate that applying our proposed approach to common image-filtering applications leads to 15--20% performance gain in scenarios with limited bandwidth, when compared to prior work that also exploits data-parallelism with RTR but includes simpler bandwidth considerations. Last but not the least, we also demonstrate how our proposed theoretical principles can be directly applied to solve related problems such as minimizing schedule length under logic resource and power constraints.
The SMesh wireless mesh network
Authors: Amir Yair , Danilov Claudiu , Musuăloiu-Elefteri Raluca , Rivera Nilo
Published: September 2010

Wireless mesh networks extend the connectivity range of mobile devices by using multiple access points, some of them connected to the Internet, to create a mesh topology and forward packets over multiple wireless hops. However, the quality of service provided by the mesh is impaired by the delays and disconnections caused by handoffs, as clients move within the area covered by multiple access points. We present the architecture and protocols of SMesh, the first transparent wireless mesh system that offers seamless, fast handoff, supporting real-time applications such as interactive VoIP. The handoff and routing logic is done solely by the access points, and therefore connectivity is attainable by any 802.11 device. In SMesh, the entire mesh network is seen by the mobile clients as a single, omnipresent access point, giving the mobile clients the illusion that they are stationary. We use multicast for access points coordination and, during handoff transitions, we use more than one access point to handle the moving client. SMesh provides a hybrid routing protocol that optimizes routes over wireless and wired links in a multihomed environment. Experimental results on a fully deployed mesh network demonstrate the effectiveness of the SMesh architecture and its intra-domain and inter-domain handoff protocols.
Probabilistic quorum systems in wireless Ad Hoc networks
Authors: Friedman Roy , Kliot Gabriel , Avin Chen
Published: September 2010

Quorums are a basic construct in solving many fundamental distributed computing problems. One of the known ways of making quorums scalable and efficient is by weakening their intersection guarantee to being probabilistic. This article explores several access strategies for implementing probabilistic quorums in ad hoc networks. In particular, we present the first detailed study of asymmetric probabilistic biquorum systems, that allow to mix different access strategies and different quorums sizes, while guaranteeing the desired intersection probability. We show the advantages of asymmetric probabilistic biquorum systems in ad hoc networks. Such an asymmetric construction is also useful for other types of networks with nonuniform access costs (e.g, peer-to-peer networks). The article includes a formal analysis of these approaches backed up by an extensive simulation-based study. The study explores the impact of various parameters such as network size, network density, mobility speed, and churn. In particular, we show that one of the strategies that uses random walks exhibits the smallest communication overhead, thus being very attractive for ad hoc networks.
What is the incoming PLD for handheld market?
Authors: LaPedus Mark
Published: September 2010

The normally quiet market for entry-level programmable-logic devices (PLDs) is suddenly heating up, with a price war possibly looming.
What is a lab-on-a-chip?
Authors: Fair Richard B.
Published: September 2010

A lab-on-a-chip (LoC) is a device that integrates multiple laboratory operations on a single chip platform and utilizes micro volumes of liquids to perform chemical or biochemical operations. The basic idea is to miniaturize and automate the tasks performed by human operators of equipment in a chemical laboratory, who transfer liquids in test tubes or beakers from one apparatus to another based upon local outcomes or established protocols. After each lab operation, the beakers and equipment are cleaned (by humans) and readied for reuse. Thus, although the chemical lab may not be automated and generally requires milliliters or liters of liquids, the tools are at least reconfigurable and reusable, giving great flexibility. Thus, a single lab with a standard set of tools and protocols can perform a large variety of tests and analyses. This, then, is a goal of a LoC device, but at a reduced scale.
What is Wireless Health?
Authors: Sarrafzadeh Majid
Published: September 2010

Recent advances in the electronics industry and wireless communication have enabled innovative domains of applications to evolve. Embedded processors and systems have become widely used in people's everyday life in various applications ranging from mobile communication to automotive industries to medical applications. The groundswell of wellness healthcare programs and patient management emphasize more involvement by patients themselves. This paradigm largely requires that patient information be readily available at the point of care, regardless of which physician the patient sees. The current proliferation of broadband wireless services, along with more powerful and convenient handheld devices, is helping introduce real-time monitoring and guidance for a wide array of patients. Low-cost sensors and wireless systems can now create a constantly vigilant and pervasive monitoring capability at home, at work, and in conventional point-of-care environments [4][5] (e.g., primary care physician offices, outpatient clinics, rehabilitation centers). Indeed, a large research community and a nascent industry is beginning to connect medical care with technology developers, vendors of wireless and sensing hardware systems [1], network service providers, and enterprise data management communities. Wearable devices focusing on personal health, rehabilitation, and early disease detection are now being prototyped. All these have led us to the new notion of "Wireless Health"
What is memristor?
Authors: Chen Yiran
Published: September 2010

The well-known three basic passive circuit elements - resistor (R), capacitor (C), and inductor (L), defines the three mathematical relations connecting the pairings of four fundamental circuit variables: electric current (i), voltage (v), electrical charge (q) and magnetic flux (phi) as:

dV = R * di (resistance)

dq = C * dv (capacitance)

d(phi) = L * di (inductance)
What are the challenges and solutions for parallel processing in EDA applications?
Authors: Spyrou Tom
Published: September 2010

EDA applications, some of the most complex and compute intensive software applications ever written, need to aggressively pursue parallel processing in order to continue to improve performance and allow the design and verification of the coming generations of complex integrated circuits. In the past, the frequency scaling of general purpose microprocessors allowed EDA applications to get the performance improvements they needed essentially for free. However, in 2004, with the cancellation of some high profile microprocessor projects, frequency scaling was brought to a virtual halt. The power consumption of the frequency scaled designs was too great. P = C Ã (V^2) Ã F. Voltage could not be scaled down enough to offset the power needed to increase frequency any further. Going forward we will not see any major increase in the frequency of general purpose microprocessors. Instead we are seeing the vast real estate on smaller geometry chips being used to place multiple processors on a single chip.
What is Predictive Technology Model (PTM)?
Authors: Cao Yu (Kevin)
Published: September 2010

The minimum feature size of CMOS technology will reach 10nm in ten years. Beyond that benchmark, the present scaling approach may have to take a different route. The grand challenge to integrated circuit design community is to identify alternative technologies, such as carbon-based electronics, integrate them into the circuit architecture, and enable continuous growth of chip scale and performance. Predictive Technology Model (PTM), which bridges the process development and circuit simulation through device modeling, is essential in assessing potentials and limits of new technology and in supporting early design prototyping.
What is flexible electronics?
Authors: Cheng Kwang-Ting (Tim) , Huang Tsung-Ching
Published: September 2010

Flexible electronics has recently attracted much attention because of their potential in providing cost-efficient solutions to large-area applications such as rollable displays and TVs, e-paper, smart sensors and transparent RFIDs. The key advantages of flexible electronics, compared with current silicon technologies, are low-cost manufacturing (e.g. ink-jet printing and roll-to-roll imprinting) and inexpensive flexible substrates (e.g. plastics). These advantages make flexible electronics an attractive candidate for next-generation consumer products which require lightweight, bendable, portable, and low-cost electronics.
What is 3D IC and what are the design challenges for 3D ICs?
Authors: Xie Yuan
Published: September 2010

Three-dimensional integrated circuits (3D ICs) are the IC chips with multiple device layers stacked together with various vertical interconnect technologies. The layers could be connected with wire-bonding, through-silicon-vias (TSV), microbump, or even inductive/capacitive contact.