bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting improvement in detection of bacteria in apheresis platelets by maintaining constant component sampling proportion
Authors: Tomasulo Peter A. , Wagner Stephen J.
Published: July 2012

BACKGROUND: In spite of interventions, approximately 1000 per 1,000,000 platelet (PLT) collections are contaminated with bacteria at collection. The current prestorage culture procedure at some blood centers is to inoculate a fixed volume from the collection bag (4‐8 mL) regardless of collection volume. The sensitivity of early testing varies with the percent of collection volume sampled. We applied the Poisson model to determine whether sampling larger volumes might increase detection at pertinent contamination levels.

STUDY DESIGN AND METHODS: The intervention was testing a fixed proportion of the collection volume from single, double, and triple collections. The Poisson model was applied to blood center data to calculate weighted average detection. Model 1 consisted of inoculating 3.2% of the collection volume from single, 1.6% from double, and 1.2% from triple PLT procedures (8 mL in each case). Model 2 consisted of inoculating 3.8% of the collection volume from all PLT procedures. Volume‐related and non–volume‐related contamination mechanisms were evaluated.

RESULTS: Testing constant proportions of the collection volume (Model 2) increases percent detection over testing constant volumes (Model 1) (68% vs. 41% detection if contamination is 30 colony‐forming units (CFUs)/collection bag and 17% vs. 9% detection if contamination is 5 CFUs/collection bag). At low levels of contamination (approx. 5 CFUs/bag), the intervention might double the number of contaminated units detected.

CONCLUSION: Based on the application of the Poisson model to detection of bacteria in PLT concentrates, inoculating cultures with slightly consistent proportions of the collection volume should lead to a reduction in false negative tests and in the number of contaminated units transfused.
Children younger than 7 years with type 1 diabetes are less physically active than healthy controls
Authors: Sundberg F , Forsander G , Fasth A , Ekelund U
Published: July 2012

Aim:  To examine if children younger than 7 years with type 1 diabetes are less physically active and spend more time sedentary than healthy children.

Methods:  Using a repeated measures case‐control study design, physical activity (PA) was measured by continuous combined accelerometer and heart rate registration for 7 days at two time points during 1 year (autumn and spring). PA data were expressed as time spent sedentary, in moderate and vigorous intensity PA and total PA. Differences between groups and gender were analysed with mixed linear regression models. In this study there were 24 children (12 girls) with type 1 diabetes mellitus and 26 (14 girls) healthy controls, all younger than 7 years at inclusion.

Results:  Children with diabetes were less active overall (p = 0.010) and spent 16 min less in moderate‐to‐vigorous PA (p = 0.006). The difference in sedentary time (21 min less) between groups was not significant (p = 0.21). Overall PA (12.1 counts/min per day, p = 0.004) and time in moderate and vigorous PA (16.0 min/day, p = 0.002) was significantly higher in boys than in girls. A significant effect of age was observed.

Conclusion:  Physical activity is significantly reduced in young children with type 1 diabetes.
Time course of changes in antioxidant activity of milk from dairy cows fed a trehalose‐supplemented diet
Authors: AOKI Naoto , SATO Kan , KANDA Shuhei , MUKAI Kazuhisa , OBARA Yoshiaki , ITABASHI Hisao
Published: July 2012

This study was to investigate the time course of changes to the antioxidant activity of milk from cows fed a trehalose‐supplemented diet, and to determine possible underlying mechanisms for observed changes. Six Holstein cows were used, and subjected to two experimental feeding periods consisting of a 1% trehalose‐supplemented diet for 10 days, followed by a basal diet only (no trehalose) for 10 days. 1,1‐Diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activities in milk were gradually increased during the trehalose supplementation period and were highest at the end of the second period. However, trehalose was not detected in the milk and plasma of dairy cows fed a diet supplemented with trehalose for 10 days, indicating that the increased antioxidant activity in the milk of trehalose‐fed cows is not due to the direct transfer of trehalose to the milk. Plasma DPPH activities exhibited a similar time course to that seen for milk. Relative superoxide dismutase (SOD) activities in the rumen were higher 3 days after the end of trehalose supplementation than at any other time during the experimental periods. These results suggested that the improved antioxidant activity in milk and plasma of cows fed a trehalose‐supplemented diet was due to improved ruminal relative SOD activity.
What Drives Security Issuance Decisions: Market Timing, Pecking Order, or Both?
Authors: Dong Ming , Loncarski Igor , Horst Jenke ter , Veld Chris
Published: July 2012

We study market timing and pecking order in a sample of debt and equity issues and share repurchases of Canadian firms from 1998 to 2007. We find that only when firms are not financially constrained is there evidence that firms issue (repurchase) equity when their shares are overvalued (undervalued) and evidence that overvalued issuers earn lower postannouncement long‐run returns. Similarly, we find that only when firms are not overvalued do they prefer debt to equity financing. These findings highlight an interaction between market timing and pecking order effects.
Senecio josei and S. superparamensis spp. nov. (Asteraceae: Senecioneae) from the Andes of Ecuador
Authors: Sklenář Petr
Published: July 2012

Research on the phylogeny of a distinct group of Andean Senecio, previously considered as Lasiocephalus, resulted in the discovery of two new species, which are here described and illustrated. Senecio josei Sklenář, which grows in rocky habitats in grass páramo in southern Ecuador, is characterized by linear leaves and a racemose or paniculate synflorescence. Senecio superparamensis Sklenář is characterized by grayish–white pubescence, solitary capitula and leafy stems, and inhabits superpáramos in northern and central Ecuador.
Clearing Away Injured Axons
Authors: VanHook Annalisa M.
Published: July 2012

The adaptor protein Sarm1 is required for Wallerian degeneration of damaged axons.
Membrane Fusion Stimulates STING
Authors: Foley John F.
Published: July 2012

Fusion of a virus with the host cell membrane acts as a danger signal to trigger an antiviral response dependent on the adaptor STING.
Redundantly Resistant to Therapy
Authors: Andrianantoandro Ernesto
Published: July 2012

Stromal cells produce factors that help cancer cells resist chemotherapy treatment.
CD39 to the Rescue
Authors: Tanhehco Yvette
Published: August 2012

Overexpression of CD39 in the lungs helps clear bacteria.
Comparative
Ex Vivo
Activity of Novel Endoperoxides in Multidrug-Resistant Plasmodium falciparum and P. vivax
Authors: Marfurt Jutta , Chalfein Ferryanto , Prayoga Pak , Wabiser Frans , Wirjanata Grennady , Sebayang Boni , Piera Kim A. , Wittlin Sergio , Haynes Richard K. , Möhrle Jörg J. , Anstey Nicholas M. , Kenangalem Enny , Price Ric N.
Published: July 2012

The declining efficacy of artemisinin derivatives against
Plasmodium falciparum
highlights the urgent need to identify alternative highly potent compounds for the treatment of malaria. In Papua Indonesia, where multidrug resistance has been documented against both
P. falciparum
and
P. vivax
malaria, comparative
ex vivo
antimalarial activity against
Plasmodium
isolates was assessed for the artemisinin derivatives artesunate (AS) and dihydroartemisinin (DHA), the synthetic peroxides OZ277 and OZ439, the semisynthetic 10-alkylaminoartemisinin derivatives artemisone and artemiside, and the conventional antimalarial drugs chloroquine (CQ), amodiaquine (AQ), and piperaquine (PIP).
Ex vivo
drug susceptibility was assessed in 46 field isolates (25
P. falciparum
and 21
P. vivax
). The novel endoperoxide compounds exhibited potent
ex vivo
activity against both species, but significant differences in intrinsic activity were observed. Compared to AS and its active metabolite DHA, all the novel compounds showed lower or equal 50% inhibitory concentrations (IC
50
s) in both species (median IC
50
s between 1.9 and 3.6 nM in
P. falciparum
and 0.7 and 4.6 nM in
P. vivax
). The antiplasmodial activity of novel endoperoxides showed different cross-susceptibility patterns in the two
Plasmodium
species: whereas their
ex vivo
activity correlated positively with CQ, PIP, AS, and DHA in
P. falciparum
, the same was not apparent in
P. vivax
. The current study demonstrates for the first time potent activity of novel endoperoxides against drug-resistant
P. vivax
. The high activity against drug-resistant strains of both
Plasmodium
species confirms these compounds to be promising candidates for future artemisinin-based combination therapy (ACT) regimens in regions of coendemicity.
Therapeutic Drug Monitoring of Posaconazole in Allogeneic Hematopoietic Stem Cell Transplantation Patients Who Develop Gastrointestinal Graft-versus-Host Disease
Authors: Tonini J. , Thiébaut A. , Jourdil J. F. , Berruyer A. S. , Bulabois C. E. , Cahn J. Y. , Stanke-Labesque F.
Published: July 2012

Posaconazole (PCZ) is the latest triazole antifungal agent that has been approved for prophylaxis of invasive aspergillosis in high-risk immunocompromised patients, such as allogeneic hematopoietic stem cell transplantation patients, who develop graft-versus-host disease (GVHD). PCZ has high interindividual variability with regard to its plasma drug trough concentrations (
C
min
). Moreover, the concentration-efficiency relationship remains to be better characterized in prophylaxis. To determine the variability factors in plasma drug concentrations, the PCZ
C
min
and clinical parameters (localization of GVHD, presence of diarrhea, and diagnosis of invasive aspergillosis) were collected retrospectively in 29 consecutive allogeneic hematopoietic stem cell transplantation patients who developed GVHD and were receiving prophylactic PCZ (200 mg, 3 times/day, for ≥7 days). Blood samples were analyzed at steady state to determine the PCZ
C
min
by liquid chromatography-tandem mass spectrometry. The average PCZ
C
min
was 1.28 ± 0.82 mg/liter (mean ± standard deviation;
n
= 292 dosages), with an intraindividual variability of 49% and an interindividual variability of 64%. Twenty percent of
C
min
s were below 0.7 mg/liter, which is considered the threshold of efficacy by the Food and Drug Administration. The patients who had gastrointestinal (GI) GVHD experienced a 24% reduction in the posaconazole
C
min
, compared with those with other localizations of GVHD. This decrease reached 33% when patients presented with diarrhea due to GI GVHD or an infectious etiology. PCZ
C
min
s were 26% lower when invasive aspergillosis was declared. These data demonstrate that GI disturbances affect drug concentrations. Thus, therapeutic monitoring of PCZ can be used to detect low drug concentrations, possibly resulting in a lack of efficacy of invasive aspergillosis prophylaxis.
Modulation of Toxin Production by the Flagellar Regulon in Clostridium difficile
Authors: Aubry Annie , Hussack Greg , Chen Wangxue , KuoLee Rhonda , Twine Susan M. , Fulton Kelly M. , Foote Simon , Carrillo Catherine D. , Tanha Jamshid , Logan Susan M.
Published: July 2012

We show in this study that toxin production in
Clostridium difficile
is altered in cells which can no longer form flagellar filaments. The impact of inactivation of
fliC
,
CD0240
,
fliF
,
fliG
,
fliM
, and
flhB-fliR
flagellar genes upon toxin levels in culture supernatants was assessed using cell-based cytotoxicity assay, proteomics, immunoassay, and immunoblotting approaches. Each of these showed that toxin levels in supernatants were significantly increased in a
fliC
mutant compared to that in the
C. difficile
630 parent strain. In contrast, the toxin levels in supernatants secreted from other flagellar mutants were significantly reduced compared with that in the parental
C. difficile
630 strain. Transcriptional analysis of the pathogenicity locus genes (
tcdR
,
tcdB
,
tcdE
, and
tcdA
) revealed a significant increase of all four genes in the
fliC
mutant strain, while transcription of all four genes was significantly reduced in
fliM
,
fliF
,
fliG
, and
flhB-fliR
mutants. These results demonstrate that toxin transcription in
C. difficile
is modulated by the flagellar regulon. More significantly, mutant strains showed a corresponding change in virulence compared to the 630 parent strain when tested in a hamster model of
C. difficile
infection. This is the first demonstration of differential flagellum-related transcriptional regulation of toxin production in
C. difficile
and provides evidence for elaborate regulatory networks for virulence genes in
C. difficile
.
Role of a New Intimin/Invasin-Like Protein in Yersinia pestis Virulence
Authors: Seo Keun Seok , Kim Jong Wan , Park Joo Youn , Viall Austin K. , Minnich Scott S. , Rohde Harold N. , Schnider Darren R. , Lim Seung Yong , Hong Joon Bae , Hinnebusch B. Joseph , O'Loughlin Jason L. , Deobald Claudia F. , Bohach Gregory A. , Hovde Carolyn J. , Minnich Scott A.
Published: July 2012

A comprehensive Tn
phoA
mutant library was constructed in
Yersinia pestis
KIM6 to identify surface proteins involved in
Y. pestis
host cell invasion and bacterial virulence. Insertion site analysis of the library repeatedly identified a 9,042-bp chromosomal gene (YPO3944), intimin/invasin-like protein (Ilp), similar to the Gram-negative intimin/invasin family of surface proteins. Deletion mutants of
ilp
were generated in
Y. pestis
strains KIM5(pCD1
+
) Pgm
−
(pigmentation negative)/, KIM6(pCD1
−
) Pgm
+
, and CO92. Comparative analyses were done with the deletions and the parental wild type for bacterial adhesion to and internalization by HEp-2 cells
in vitro
, infectivity and maintenance in the flea vector, and lethality in murine models of systemic and pneumonic plague. Deletion of
ilp
had no effect on bacterial blockage of flea blood feeding or colonization. The
Y. pestis
KIM5 Δ
ilp
strain had reduced adhesion to and internalization by HEp-2 cells compared to the parental wild-type strain (
P
< 0.05). Following intravenous challenge with
Y. pestis
KIM5 Δ
ilp
, mice had a delayed time to death and reduced dissemination to the lungs, livers, and kidneys as monitored by
in vivo
imaging using a
lux
reporter system (
in vivo
imaging system [IVIS]) and bacterial counts. Intranasal challenge in mice with
Y. pestis
CO92 Δ
ilp
had a 55-fold increase in the 50% lethal dose ([LD
50
] 1.64 × 10
4
CFU) compared to the parental wild-type strain LD
50
(2.98 × 10
2
CFU). These findings identified Ilp as a novel virulence factor of
Y. pestis
.
Prosthetic valve thrombosis: keeping the valve ticking!
Authors: Jamil Haqeel A , Hesketh Christopher , Stevenson Robert N
Published: August 2012

Prosthetic valve thrombosis is a serious acute complication of mechanical valvular replacement, with significant mortality and morbidity. This case highlights the key diagnostic features and the role of thrombolysis in treatment.
Linking deadwood-associated beetles and fungi with wood decomposition rates in managed black spruce forests1This article is one of a selection of papers from the International Symposium on Dynamics and Ecological Services of Deadwood in Forest Ecosystems.
Authors: Jacobs Jenna M. , Work Timothy T.
Published: August 2012

Deadwood-associated insects and saprotrophic fungi are principal agents of wood decomposition in boreal forest. Silvicultural treatments that alter microclimate and availability of deadwood likely affect composition and growth rates of both insect and fungal communities, leading to changes in wood decomposition rates. Here, we relate both saproxylic beetle and dominant polypore assemblages with woody decomposition rates and environmental variables in experimental partial cuts, clearcuts, and uncut controls using a series of causal models to determine the relationship between stand structure, biodiversity, and ecosystem function in black spruce ( Picea mariana (Mill.) BSP) forests. Overall beetle and fungal composition differed between uncut stands and harvested stands. Main effects of harvesting included large increases in wood-feeding beetles and the fungus Gloeophyllum sepiarium (Wul.:Fr.) Karst. We suggest that these species were promoted by specific alterations in microhabitat conditions of deadwood. Within clearcuts specifically, changes in species composition and significantly more fungal degree-days resulted in significantly higher decomposition rates. We concluded that levels of partial cutting in the range of 15%–20% retention were not sufficient to maintain predisturbance communities but were sufficient to maintain wood decomposition rates similar to uncut stands.
Distribution of white spruce lateral fine roots as affected by the presence of trembling aspen: root mapping using simple sequence repeat DNA profiling
Authors: Lawrence Derek Joseph , Luckai N. , Meyer W.L. , Shahi C. , Fazekas A.J. , Kesanakurti P. , Newmaster S.
Published: August 2012

Mixedwood forests of white spruce ( Picea glauca (Moench) Voss) and trembling aspen ( Populus tremuloides Michx.) may possess ecological advantages over monospecific white spruce stands. Belowground competition may be reduced through vertically stratified roots; facilitation of growth may occur in upper soil layers through nutrient-rich trembling aspen litterfall. These effects may incentivize white spruce to preferentially exploit upper soil layers in mixedwood stands, resulting in wider root systems. This research contrasted white spruce fine root (diameter <2 mm) distributions in organic layers of white spruce and mixedwood stands. Research occurred at the Fallingsnow Ecosystem Project site in northwestern Ontario. Eighteen plots represented mixedwood and pure white spruce stands. Trees were mapped; foliage and root samples were collected. Roots were separated by species and scanned to determine length. Simple sequence repeat DNA profiles were determined for all white spruce trees and for 45 white spruce root fragments per plot. Root and tree DNA profiles were matched; corresponding distances were calculated. Most (80%) root fragments were within 3.2 m of tree stems. Root prevalence decreased rapidly with distance. Organic layer pH was significantly less acidic in mixedwood plots, but only in one block. A subtle significant trend towards wider root distributions occurred in mixedwood stands.
Variation in mass and nutrient concentration of leaf litter across years and sites in a northern hardwood forest
Authors: Yanai Ruth D. , Arthur Mary A. , Acker Marty , Levine Carrie R. , Park Byung Bae
Published: August 2012

Leaf litterfall represents an important nutrient flux in forests, but separating leaves by species and collecting fresh litter annually for nutrient analysis is time-consuming and expensive. To quantify the sources of variation in litterfall nutrient estimates and guide optimal allocation of research effort, we analyzed nutrient concentration (5 years) and mass (6 years) of leaf litter for nine tree species in 13 northern hardwood sites. Coefficients of variation (CVs) in nutrient concentration were higher across sites than over time within sites for most elements; phosphorus was especially variable across sites (56% CV). Thus, to estimate litterfall nutrient fluxes accurately in forests of this type, nutrient analyses should be site-specific as well as species-specific but may not need to be repeated annually (CVs over time averaged 17% for calcium, 21% for magnesium, 28% for potassium, and 32% for phosphorus concentration). Total leaf litterfall mass varied considerably from year to year, ranging from 234 to 370 g·m–2 averaged over 13 sites. We recommend that litter collectors be elevated above the ground to avoid oversampling during extreme wind events. Use of species-specific allometric equations, or even basal area, to estimate the species composition of total litter mass may obviate the need to sort litter by species.
Differential persistence of blue ash and white ash following emerald ash borer invasion
Authors: Tanis Sara R. , McCullough Deborah G.
Published: August 2012

Catastrophic mortality of North American ash ( Fraxinus spp.) caused by Agrilus planipennis Fairmaire has been attributed to the lack of coevolved resistance between native ash species and this Asian invader. Although A. planipennis host preference or tree resistance can vary, all North American ash species are presumably highly vulnerable to A. planipennis. We inventoried live and dead blue ash ( Fraxinus quadrangulata Michx.) and white ash ( Fraxinus americana L.) in two southeastern Michigan woodlots several years after the A. planipennis invasion to assess their survival. Agrilus planipennis populations in this area peaked in approximately 2005, and the region is now characterized by nearly complete ash mortality. At the Plymouth site, 71% of the original 380 blue ash were alive, whereas only 29 saplings of the original 187 white ash were alive. At the Superior Township site, 63% of the original 210 blue ash were living, whereas all 125 white ash were dead. More than 80% of the blue ash had evidence of previous A. planipennis colonization, but 87% appeared healthy in 2011. Tree diameter did not consistently affect survival, and live and dead trees of both species were distributed across sites, indicating that differential survival was not attributable to localized conditions.
Do small mammals prey upon an invasive ectoparasite of cervids?
Authors: Kaunisto Sirpa , Kortet Raine , Härkönen Sauli , Kaitala Arja , Laaksonen Sauli , Ylönen Hannu
Published: August 2012

Predation is often considered an important factor for population regulation and in some cases for the invasion success of prey. Small mammalian predation may be a major force in the population regulation of many ground-dwelling invertebrate species. The deer ked ( Lipoptena cervi (L., 1758)) is an ectoparasitic fly of cervids. The species has a large distribution area and it has relatively rapidly spread in northern Europe during the previous four decades. The factors possibly regulating the distribution and invasion of this fly are poorly known. During the off-host stage of several months, pupae of deer ked are likely exposed to many ground-dwelling predators. To study whether small mammals would feed on deer keds, we conducted experiments by serving pupae of deer ked to wild-captured common shrews ( Sorex araneus L., 1758), bank voles ( Myodes glareolus (Schreber, 1780)), field voles ( Microtus agrestis (L., 1761)), and semi-wild bank voles, and assessed pupal survival. As a control, we provided alternative food including common nutrients used by small mammals in their natural habitats. The results show that variable amounts of pupae of deer ked are consumed by all small-mammal species studied. Surprisingly, insectivorous and most of the time food-constrained shrews consumed less pupae than granivorous–herbivorous voles.
Cuckoldry features of introduced pumpkinseed sunfish (Lepomis gibbosus) in contrasting environmental conditions in southern Europe
Authors: Almeida D. , Tobes I. , Miranda R. , Copp G.H.
Published: August 2012

Reproduction of pumpkinseed sunfish ( Lepomis gibbosus (L., 1758)) in the species’ native range often involves cuckoldry, consisting of dominant nest-guarding (parental) males and the participation by small “sneaker” males. However, it remains unknown whether this behaviour occurs in populations of non-native pumpkinseed. Thus, the present study describes the phenotypic features of cuckoldry under contrasting environmental conditions (lentic versus lotic) in southern Europe. Parental and sneaker pumpkinseeds were captured in the summer of 2011 from the River Bullaque (central Spain) and from the Encinarejo Reservoir (southern Spain). No differences in total length were observed in sneaker males, although individuals of ages 1+ and 2+ were significantly predominant in the river and the reservoir, respectively. Parental males were larger and older in the reservoir than in the river. Gonadosomatic and hepatosomatic indices were significantly higher in sneaker than in parental males at both sites. Body condition was lower in sneaker males in the river. Both ingested biomass and the proportion of full stomachs were lower in parental males at both sites, being significant in all cases except ingested biomass in the river. Sneaker males achieved a higher gonadosomatic index than parental males. In contrast, parental males had higher body condition indices than sneakers. Results demonstrate the high ecological plasticity of pumpkinseed sunfish to display natural behaviours out of its native area.
DRESSED BOSONS AND EFFECTIVE TEMPERATURE — A FORMALISM FOR HELIUM II
Authors: MAĆKOWIAK JAN , BORYCKI DAWID
Published: August 2012

The thermodynamics of a free Bose gas with effective temperature scale [Formula: see text] and hard-sphere Bose gas with the [Formula: see text] scale are studied. [Formula: see text] arises as the temperature experienced by a single particle in a quantum gas with 2-body harmonic oscillator interaction V osc , which at low temperatures is expected to simulate, almost correctly, the attractive part of the interatomic potential V He between 4 He atoms. The repulsive part of V He is simulated by a hard-sphere (HS) potential. The thermodynamics of this system of HS bosons, with the [Formula: see text] temperature scale (HSET), and particle mass and density equal to those of 4 He , is investigated, first, by the Bogoliubov–Huang method and next by an improved version of this method, which describes He II in terms of dressed bosons and takes approximate account of those terms of the 2-body repulsion which are linear in the zero-momentum Bose operators a0, [Formula: see text] (originally rejected by Bogoliubov). Theoretical heat capacity CV(T) exhibits good agreement, below 1.9 K, with the experimental heat capacity graph observed in 4 He at saturated vapour pressure. The phase transition to the He II phase, occurs in the HSET at Tλ = 2.17 K, and is accompanied, in the modified HSET version, by a singularity of CV(T). The fraction of atoms in the momentum condensate at 0 K equals 8.86% and agrees with other theoretical estimates for He II. The fraction of normal fluid falls to 8.37% at 0 K which exceeds the value 0% found in He II.
PROPAGATION OF TRANSVERSELY BOUNDED NONLINEAR ELECTROMAGNETIC PULSES THROUGH PERIODIC MEDIA
Authors: CASTREJON-M C. , GRIMALSKY V. , KOSHEVAYA S. , ZAMUDIO-LARA A.
Published: August 2012

Nonlinear propagation of optical pulses of finite transverse widths through periodic structures with and without defects is investigated numerically and the subject of investigation is a stack of alternating linear and cubically nonlinear layers of submicron thicknesses is considered. The simulations are based on a modified equation for the pulse envelope and modified boundary conditions where both the diffraction and possible focusing of the pulse are taken into account. The simulations demonstrate an essential influence of defects within the periodic structure on the nonlinear propagation of optical pulses when the carrier frequency is chosen within the stop-band of the structure with the defect.
Agile software assessment with Moose
Authors: Nierstrasz Oscar
Published: July 2012

During software maintenance, much time is spent reading and assessing existing code. Unfortunately most of the tools available for exploring and assessing code, such as browsers, debuggers and profilers, focus on development tasks, and offer little to support program understanding. We present a platform for software and data analysis, called Moose, which enables the rapid development of custom tools for software assessment. We demonstrate how Moose supports agile software assessment through a series of demos, we illustrate some of the custom tools that have been developed, and we draw various lessons learned for future work in this domain
A report on software engineering education workshop
Authors: Shukla Rakesh , Sureka Ashish , Joshi Rushikesh , Mall Rajib
Published: July 2012

In this report, we present a summary and a few reflections of a one day workshop on Software Engineering Education held on February 22, 2012 at Indian Institute of Technology, Kanpur, India collocated with the 5th India Software Engineering Conference. We identify a gap and believe there is a need for creating an annual discussion forum that serves the need of having a regular workshop for software engineering education in India and also benefit the global software engineering education community by sharing the workshop insights and results by a publication process. The workshop consists of two keynotes, one from academia and one from industry, two subgroups discussions and presentations by the subgroups on their discussions. Three systematic techniques, invitation of position statements, set up of a Google group and an online survey, were employed before the workshop to estimate number of participants, subgroups and size of each subgroup for effective discussions. Twenty participants attended the workshop. The keynotes were on Using Collaborative Learning and Divergent Thinking to Teach Software Engineering and on Software Engineering Competency Development Model. Three topics were selected for subgroups discussions by the participants: use of various methods, such as learning while playing and project-based software engineering, over Power Point lecture, requirements and needs of undergraduate software engineering degree program from the perspective of Indian software industry and curriculum content, coverage, and impact of software engineering courses. The workshop was a successful endeavor and the response in terms of the contributions by participants is a clear indicator and confirmation of the need of having a focused discussion forum for brainstorming on software engineering education in India
Computational intelligence in software cost estimation
Authors: Benala Tirimula Rao , Dehuri Satchidananda , Mall Rajib
Published: July 2012

One of the key features for the failure of project estimation techniques is the selection of inappropriate estimation models. Further, noisy data poses a challenge to build accurate estimation models. Therefore, the software cost estimation (SCE) is a challenging problem that has attracted many researchers over the past few decades. In the recent times,the use of computational intelligence methodologies for software cost estimation have gained prominence. This paper reviews some of the commonly used computational intelligence (CI) techniques and analyzes their application in software cost estimation and outlines the emerging trends in this area
A new approach to generate and optimize test cases for UML state diagram using genetic algorithm
Authors: Gulia Preeti , Chillar R. S.
Published: July 2012

Software testing is an important part of the software development process. The testing effort is divided into three parts: test case generation, test execution and test evaluation. Test case generation is the center of testing process and automating. It saves time and efforts and reduces the number of errors and faults. To decrease the elevated cost of software testing and to increase the reliability of the testing processes, a new method has been created to automate the testing process. This paper proposes a new approach to generate and optimize test cases from UML State Chart diagram using Genetic Algorithm. To generate the new test sequence the method of crossover has been applied from the Genetic Algorithm and the efficiency of the test sequences is evaluated by Mutation Analysis
A comparative study of bayesian and fuzzy approach to assess and predict maintainability of the software using activity-based quality model
Authors: Jeet Kawal , Dhir Renu , Verma Harsh
Published: July 2012

Quality is considered as one of the most important aspects responsible for the success of the software. The developers as well as the end users of the software have accepted maintainability as a significant characteristic due to its economic implications. Several subjective techniques have been developed in research to assess and predict maintainability but all have been unsuccessful to do it practically and most of them even fail to define it appropriately. The activity-based quality model is one of the techniques that have been found to be successful in defining maintainability. This model assesses maintainability in terms of average efforts required to maintain software but lacks quantitative aspect that has been further added by using Bayesian Network. In this paper, a comparison of the Bayesian approach and Fuzzy approach to deal with this model quantitatively has been done wherein; Fuzzy approach has been found to be better than Bayesian
Preprocessing the web server logs
Authors: Reddy K. Sudheer , Varma G. Partha Saradhi , Babu I. Ramesh
Published: July 2012

Data preprocessing is an important activity for discovering behavioral patterns. The analysis of web logs is an essential task for System Administrators to safeguard adequate bandwidth and to maintain server capacity on their business websites. A web Log file represents user activities occurring over a period of time. Web log files offer valuable insight into the effective usage of the web site. It helps maintain an account of the actual usage in a regular working system as compared to the virtual setting of a usability lab. This research paper focuses on the preprocessing techniques implemented on a specially designed Web Sift (WebIS) tool on an IIS web server and also proposes some efficient heuristics and techniques
Divide and conquer high-level synthesis design space exploration
Authors: Schafer Benjamin Carrion , Wakabayashi Kazutoshi
Published: August 2012

A method to accelerate the Design Space Exploration (DSE) of behavioral descriptions for high-level synthesis based on a divide and conquer method called Divide and Conquer Exploration Algorithm (DC-ExpA) is presented. DC-ExpA parses an untimed behavioral description given in C or SystemC and clusters interdependent operations which are in turn explored independently by inserting synthesis directives automatically in the source code. The method then continues by combining the exploration results to obtain only Pareto-optimal designs. This method accelerates the design space exploration considerably and is compared against two previous methods: an Adaptive Simulated Annealer Exploration Algorithm (ASA-ExpA) that shows good optimality at high runtimes, and a pattern matching method called Clustering Design Space Exploration Acceleration (CDS-ExpA) that is fast but suboptimal. Our proposed method is orthogonal to previous exploration methods that focus on the exploration of resource constraints, allocation, binding, and/or scheduling. Our proposed method on contrary sets local synthesis directives that decide upon the overall architectural structure of the design (e.g., mapping certain arrays to memories or registers). Results show that DC-ExpA explores the design space on average 61% faster than ASA-ExpA, obtaining comparable results indicated by several quality indicators, for example, distance to reference Pareto-front, hypervolume, and Pareto dominance. Compared to CDS-ExpA it is 69% slower, but obtains much betters results compared to the same quality indicators.
Model-driven automation for simulation-based functional verification
Authors: Linehan Éamonn , O'Toole Eamonn , Clarke Siobhán
Published: August 2012

Developing testbenches for dynamic functional verification of hardware designs is a software-intensive process that lies on the critical path of electronic system design. The increasing capabilities of electronic components is contributing to the construction of complex verification environments that are increasingly difficult to understand, maintain, extend, and reuse across projects. Model-driven software engineering addresses issues of complexity, productivity, and code quality through the use of high-level system models and subsequent automatic transformations. Reasoning about verification testbench decomposition becomes simpler at higher levels of abstraction. In particular, the aspect-oriented paradigm, when applied at the model level, can minimize the overlap in functionality between modules, improving maintainability and reusability. This article presents an aspect-oriented model-driven engineering process and toolset for the development of hardware verification testbenches. We illustrate how this process and toolset supports modularized design and automatic transformation to verification environment-specific models and source code through an industry case study.
High-performance clock mesh optimization
Authors: Guthaus Matthew R. , Hu Xuchu , Wilke Gustavo , Flach Guilherme , Reis Ricardo
Published: August 2012

Clock meshes are extremely effective at producing low-skew regional clock networks that are tolerant of environmental and process variations. For this reason, clock meshes are used in most high-performance designs, but this robustness consumes significant power. In this work, we present two techniques to optimize high-performance clock meshes. The first technique is a mesh perturbation methodology for nonuniform mesh routing. The second technique is a skew-aware buffer placement through iterative buffer deletion. We demonstrate how these optimizations can achieve significant power reductions and a near elimination of short-circuit power. In addition, the total wire length is decreased, the number of required buffers is decreased, and both skew and robustness are improved on average when variation is considered.
Abstracts of Papers to appear in Special Supplemental Issue of TECS (v11, iSupplemental1)
Authors: TECS Staff
Published: July 2012

In order to speed up the publication process, we have begun to publish supplemental online-only issues. The following abstracts describe the articles in the first such issue, Vol. 11S(1). These articles are available in the Digital Library.
An Efficient Finite Field Multiplier Using Redundant Representation
Authors: Namin Ashkan Hosseinzadeh , Wu Huapeng , Ahmadi Majid
Published: July 2012

An efficient word-level finite field multiplier using redundant representation is proposed. The proposed multiplier has a significantly higher speed, compared to previously proposed word-level architectures using either redundant representation or optimal normal basis type I, at the expense of moderately higher area complexity. Furthermore, the new design out-performs other similar proposals when considering the product of area and delay as a measure of performance. ASIC Realization of the proposed design using TSMC’s .18
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CMOS technology for the binary field size of 163 is also presented.
On the Impact of Manufacturing Process Variations on the Lifetime of Sensor Networks
Authors: Garg Siddharth , Marculescu Diana
Published: July 2012

The lifetime of individual nodes in a sensor network depends strongly on the leakage power of the nodes in idle state. With technology scaling, variability in leakage power dissipation of sensor nodes will cause increased variability in their lifetimes. In this article, we analyze how the lifetime variations of sensor nodes affect the performance of the sensor network as a whole. We demonstrate the use of the proposed framework to explore deployment cost versus performance trade-offs for sensor networks. Results indicate that up to 37% improvement in the critical lifetime of a sensor network can be obtained with a 20% increase in deployment cost.
Optimization of Shared High-Performance Reconfigurable Computing Resources
Authors: Smith Melissa C. , Peterson Gregory D.
Published: July 2012

In the field of high-performance computing, systems harboring reconfigurable devices, such as field-programmable gate arrays (FPGAs), are gaining more widespread interest. Such systems range from supercomputers with tightly coupled reconfigurable hardware to clusters with reconfigurable devices at each node. The use of these architectures for scientific computing provides an alternative for computationally demanding problems and has advantages in metrics, such as operating cost/performance and power/performance. However, performance optimization of these systems can be challenging even with knowledge of the system’s characteristics. Our analytic performance model includes parameters representing the reconfigurable hardware, application load imbalance across the nodes, background user load, basic message-passing communication, and processor heterogeneity. In this article, we provide an overview of the analytical model and demonstrate its application for optimization and scheduling of high-performance reconfigurable computing (HPRC) resources. We examine cost functions for minimum runtime and other optimization problems commonly found in shared computing resources. Finally, we discuss additional scheduling issues and other potential applications of the model.
Exploring Experienced Professionals’ Reflections on Computing Education
Authors: Exter Marisa , Turnage Nichole
Published: August 2012

This exploratory qualitative study examines computing professional’s memories of their own formal and non-formal educational experiences, their reflections on how these have prepared them for their professional roles, and their recommendations for an “ideal” undergraduate degree program. Data was collected through semi-structured interviews of experienced computing professionals. Ongoing on-the-job learning is a natural part of professionals’ work lives. Participants indicate that important elements in an undergraduate degree program include foundational computing topics, development of critical thinking and communications skills, and a strong emphasis on experiences similar to those encountered in a professional position, such as complex, realistic group projects. Specific programming languages and technologies should be used only as practice in solving problems and learning on one’s own.
Single-trial EEG classification of artifacts in videos
Authors: Mustafa Maryam , Guthe Stefan , Magnor Marcus
Published: July 2012

In this article we use an ElectroEncephaloGraph (EEG) to explore the perception of artifacts that typically appear during rendering and determine the perceptual quality of a sequence of images. Although there is an emerging interest in using an EEG for image quality assessment, one of the main impediments to the use of an EEG is the very low Signal-to-Noise Ratio (SNR) which makes it exceedingly difficult to distinguish neural responses from noise. Traditionally, event-related potentials have been used for analysis of EEG data. However, they rely on averaging and so require a large number of participants and trials to get meaningful data. Also, due the the low SNR ERP's are not suited for single-trial classification.

We propose a novel wavelet-based approach for evaluating EEG signals which allows us to predict the perceived image quality from only a single trial. Our wavelet-based algorithm is able to filter the EEG data and remove noise, eliminating the need for many participants or many trials. With this approach it is possible to use data from only 10 electrode channels for single-trial classification and predict the presence of an artifact with an accuracy of 85%. We also show that it is possible to differentiate and classify a trial based on the exact type of artifact viewed. Our work is particularly useful for understanding how the human visual system responds to different types of degradations in images and videos. An understanding of the perception of typical image-based rendering artifacts forms the basis for the optimization of rendering and masking algorithms.
One-scan rule extraction to explain significant vehicle interactions with guaranteed error value
Authors: Florez Omar U. , Dyreson Curtis
Published: July 2012

Counting frequent itemsets allows us to compute the importance of items over a stream of data. Translating this concept to video streams imposes the need of representing activities as a sequence of activities over a video stream. In this paper, we present a model to find approximate co-occurring associations between activities from video stream data considering an unsupervised clustering of activities. We show that a hierarchical Topic Model of two stochastic processes is needed to jointly learn both an unknown number of activities in the video and the visual features that positively correlate for each activity. Unlike most of previous works, we decouple the analysis of associations between multiple moving objects from the discovery of activities. While the discovery of activities is an off-line process in which event distributions are grouped, the discovery of rules is an on-line process that approximates the importance of each rule with guaranteed error value. Our method reduces space complexity by adapting the algorithm to the amount of memory available before any process to update frequency values for itemsets is incrementally performed. The most visible aspect of this effort is the incremental generation of rules that discover the interaction of frequent activities for current scenes. Our experimental results show that our approach efficiently and automatically discovers sets of activities in a video stream coming from surveillance videos containing complex traffic scenes governed by multiple semaphores, while evaluating their frequent occurrence and co-occurring relationships.
The effect of high-frequency conditioning stimulation of human skin on reported pain intensity and event-related potentials
Authors: van den Broeke Emanuel N. , van Heck Casper H. , Ceelen Linda A. J. M. , van Rijn Clementina M. , van Goor Harry , Wilder-Smith Oliver H. G.
Published: August 2012

High-frequency conditioning electrical stimulation (HFS) of human skin induces an increased pain sensitivity to mechanical stimuli in the surrounding nonconditioned skin. The aim of this study was to investigate the effect of HFS on reported pain sensitivity to single electrical stimuli applied within the area of conditioning stimulation. We also investigated the central nervous system responsiveness to these electrical stimuli by measuring event-related potentials (ERPs). Single electrical test stimuli were applied in the conditioned area before and 30 min after HFS. During electrical test stimulation, the reported pain intensity (numerical rating scale) and EEG (ERPs) were measured. Thirty minutes after conditioning stimulation, we observed a decrease of reported pain intensity at both the conditioned and control (opposite arm) skin site in response to the single electrical test stimuli. In contrast, we observed enhanced ERP amplitudes after HFS at the conditioned skin site, compared with control site, in response to the single electrical test stimuli. Recently, it has been proposed that ERPs, at least partly, reflect a saliency detection system. Therefore, the enhanced ERPs might reflect enhanced saliency to potentially threatening stimuli.
Detection of Postcoronary Stent Complication: Utility of 64-Slice Multidetector CT
Authors: Bharati Alpa , Merchant Suleman , Suvarna Tilak , Parashar Neha
Published: July 2012

Coronary stent fracture is a known complication of coronary arterial stent placements. Multiple long-term risks are also associated with drug eluting stents. 64-slice multidetector CT (MDCT) coronary angiography has been shown to detect poststent complications such as instent stenosis, thrombosis, stent migration and stent fractures. We report a case of stent fracture in a patient who underwent RCA stenting with associated RCA perforation and almost complete thrombosis of the RCA and peristent fibrinoid collection. This is a rare case of stent fracture with perforation of the RCA. The paper highlights the role of 64-row multidetector computed tomography (MDCT) in evaluation of such poststent placement complications.