bluuebunny/crossref_metadata_2025 huggingface dataset:
Adiposity and aerobic fitness are associated with metabolic disease risk in children
Authors: Parrett Anne L. , Valentine Rudy J. , Arngrímsson Sigurbjörn Á. , Castelli Darla M. , Evans Ellen M.
Published: February 2011

To examine the relative association of physical activity, cardiorespiratroy fitness (CRF), and adiposity with risk for metabolic disease in prepubescent children. Forty-six prepubescent children (age, 9.4 ± 1.7 years; 24 males) were assessed for adiposity (%fat) via dual-energy X-ray absorptiometry, CRF with a peak graded exercise test, and physical activity using pedometers. Metabolic disease risk was assessed by a composite score of the following factors: waist circumference (WC), mean arterial pressure (MAP), triacylglycerol (TAG), total cholesterol to high-density lipoprotein cholesterol ratio (TC/HDL-C ratio), glucose, and insulin. Adiposity was correlated with metabolic disease risk score, as well as homeostasis model assessment of insulin resistance (HOMA-IR), TAG, TC/HDL-C ratio, WC, insulin, and MAP (r range = 0.33 to 0.95, all p < 0.05). Physical activity was negatively associated with metabolic disease risk score, as well as HOMA-IR, TAG, WC, insulin, and MAP (r range = –0.32 to –0.49, all p < 0.05). CRF was inversely associated with metabolic disease risk score and HOMA-IR, TAG, TC/HDL-C ratio, WC, insulin, and MAP (r range = –0.32 to –0.63, all p < 0.05). Compared across fitness–physical activity and fatness groups, the low-fit–high-fat and the low-activity–high-fat groups had higher metabolic risk scores than both low-fat groups. Regression analyses revealed sexual maturity (β = 0.27, p = 0.044) and %fat (β = 0.49, p = 0.005) were the only independent predictors of metabolic disease risk score, explaining 4.7% and 9.5% of the variance, respectively. Adiposity appears to be an influential factor for metabolic disease risk in prepubescent children, and fitness is protective against metabolic disease risk in the presence of high levels of adiposity.
Gender differences in whole-body fat oxidation kinetics during exercise
Authors: Chenevière Xavier , Borrani Fabio , Sangsue David , Gojanovic Boris , Malatesta Davide
Published: February 2011

Discrepancies appear in studies comparing fat oxidation between men and women. Therefore, this study aimed to quantitatively describe and compare whole-body fat oxidation kinetics between genders during exercise, using a sinusoidal (SIN) model. Twelve men and 11 women matched for age, body mass index, and aerobic fitness (maximal oxygen uptake and maximal power output per kilogram of fat-free mass (FFM)) performed submaximal incremental tests (Incr) with 5-min stages and a 7.5% maximal power output increment on a cycle ergometer. Fat oxidation rates were determined using indirect calorimetry, and plotted as a function of exercise intensity. The SIN model, which includes 3 independent variables (dilatation, symmetry, translation) that account for the main quantitative characteristics of kinetics, was used to mathematically describe fat oxidation kinetics and to determine the intensity (Fatmax) eliciting the maximal fat oxidation (MFO). During Incr, women exhibited greater fat oxidation rates from 35% to 85% maximal oxygen uptake, MFO (6.6 ± 0.9 vs. 4.5 ± 0.3 mg·kg FFM−1·min−1), and Fatmax(58.1% ± 1.9% vs. 50.0% ± 2.7% maximal oxygen uptake) than men (p < 0.05). While men and women showed similar global shapes of fat oxidation kinetics in terms of dilatation and symmetry (p > 0.05), the fat oxidation curve tended to be shifted toward higher exercise intensities in women (rightward translation, p = 0.08). These results support the idea that women have a greater reliance on fat oxidation than men during submaximal exercise, but also indicate that this greater fat oxidation is shifted toward higher exercise intensities in women than in men.
Fat adaptation in well-trained athletes: effects on cell metabolism
Authors: Yeo Wee Kian , Carey Andrew L. , Burke Louise , Spriet Lawrence L. , Hawley John A.
Published: February 2011

The performance of prolonged (>90 min), continuous, endurance exercise is limited by endogenous carbohydrate (CHO) stores. Accordingly, for many decades, sports nutritionists and exercise physiologists have proposed a number of diet-training strategies that have the potential to increase fatty acid availability and rates of lipid oxidation and thereby attenuate the rate of glycogen utilization during exercise. Because the acute ingestion of exogenous substrates (primarily CHO) during exercise has little effect on the rates of muscle glycogenolysis, recent studies have focused on short-term (<1–2 weeks) diet-training interventions that increase endogenous substrate stores (i.e., muscle glycogen and lipids) and alter patterns of substrate utilization during exercise. One such strategy is “fat adaptation”, an intervention in which well-trained endurance athletes consume a high-fat, low-CHO diet for up to 2 weeks while undertaking their normal training and then immediately follow this by CHO restoration (consuming a high-CHO diet and tapering for 1–3 days before a major endurance event). Compared with an isoenergetic CHO diet for the same intervention period, this “dietary periodization” protocol increases the rate of whole-body and muscle fat oxidation while attenuating the rate of muscle glycogenolysis during submaximal exercise. Of note is that these metabolic perturbations favouring the oxidation of fat persist even in the face of restored endogenous CHO stores and increased exogenous CHO availability. Here we review the current knowledge of some of the potential mechanisms by which skeletal muscle sustains high rates of fat oxidation in the face of high exogenous and endogenous CHO availability.
Energy expenditure characteristics of weight lifting: 2 sets to fatigue
Authors: Scott Christopher B. , Leary Michael P. , TenBraak Andrew J.
Published: February 2011

We investigated the work performed and energy expenditure characteristics within and among 2 sets of the bench press at 70%, 80%, and 90% of 1 repetition maximum (1RM). For both sets fatigue was the end point. We asked: do multiple sets affect subsequent work output along with aerobic, anaerobic, and excess postexercise oxygen consumption (EPOC) contributions? Ten males participated. Work was significantly less for the 2nd set within the 70% and 80% protocols, but not the 90% protocol. Anaerobic (glycolytic) energy expenditure was less for the 2nd set within all protocols. However, within all protocols, the work / energy expenditure ratio was not different between sets. Overall work was significantly different among protocols, becoming less as the weight lifted was increased: 70%, 637.1 ± 122.4 J; 80%, 512.4 ± 93.4 J; 90%, 324.7 ± 92.6 J (p < 0.001). EPOC was not different among protocols after the 1st set, 2nd set, or combined overall. Moreover, the overall EPOC did not correlate with overall work performed (r = 0.31, p = 0.11). EPOC overall did correlate with aerobic (r = 0.68, p < 0.001) and anaerobic (r = 0.65, p < 0.001) energy expenditures. In terms of a work / energy expenditure ratio, the least amount of completed work at 90% 1RM required greater energy expenditure as compared with 70% and 80% because of an EPOC that is similar for all. As more work is completed (i.e., lower weight, more repetitions), aerobic and anaerobic exercise energy expenditures appear to increase accordingly, yet absolute EPOC remains essentially unchanged, contributing less to the overall energy expenditure.
The extent of aerobic system activation during continuous and interval exercise protocols in young adolescents and men
Authors: Zafeiridis Andreas , Rizos Stylianos , Sarivasiliou Haralampos , Kazias Anastassios , Dipla Konstantina , Vrabas Ioannis S.
Published: February 2011

This study assessed the extent of aerobic system activation in young adolescents and men during heavy continuous (HC), short-interval (SI), and long-interval (LI) aerobic exercise protocols, and compared this response between the 2 age groups in the 3 protocols. Ten young adolescents (aged 13.2 ± 0.3 years) and 10 men (aged 21.0 ± 1.6 years) completed a maximal incremental test, an HC exercise protocol (83% of maximal aerobic velocity; MAV), an SI exercise protocol (30 s at 110% MAV with 30 s at 50%), and an LI exercise protocol (3 min at 95% MAV with 3 min at 35%). Oxygen consumption and heart rate were measured continuously, and blood samples were obtained for lactate determination. Men completed more runs and distance in the SI protocol (p < 0.05) than adolescents; however, there were no age differences in the number of LI runs and in the duration of HC protocol. In both age groups, more time was spent above 90% and 95% of maximal oxygen consumption (p < 0.05), and a higher percentage of maximal oxygen consumption was reached in the LI compared with the HC and SI protocols, with no differences between the HC and SI protocols. Although within each protocol the percentage of maximal oxygen consumption achieved and time spent above 90% and 95% of maximal oxygen consumption was not different between age groups, the time spent at 80% maximal oxygen consumption was longer for adolescents than men in the HC protocol, and longer for men than boys in the SI protocol (p < 0.05). In conclusion, all protocols elicited high levels of aerobic activation in both age groups. The LI protocol taxed the aerobic system at 90%–100% of maximal oxygen consumption for a longer time when compared with the HC and SI protocols in young adolescents and in men. However, differences were observed between groups in taxing the aerobic system at 80% maximal oxygen consumption: in young adolescents, the HC protocol allowed longer running time than the LI and SI protocols, while in men there were no differences among protocols.
Estimated fluid and sodium balance and drink preferences in elite male junior players during an ice hockey game
Authors: Logan-Sprenger Heather M. , Palmer Matthew S. , Spriet Lawrence L.
Published: February 2011

Research in many sports suggests that losing ∼2% of body mass (BM) through sweating impairs athletic performance, although this has not been tested in ice hockey players. This study investigated pregame hydration, and on-ice sweat loss, fluid intake, and sodium (Na+) balance of elite male junior players during an ice hockey game. Twenty-four players (2 goalies, 7 defensemen, 15 forwards) volunteered to participate in the study (age, 18.3 ± 0.3 years; weight, 86.5 ±1.6 kg; height, 184.1 ± 1.3 cm). Players were weighed pre- and postgame, fluid and sodium intake were monitored throughout the game, and fluid and Na+ balance were determined within the time between BM measurements. Sweat Na+ loss was calculated based on sweat loss and sweat [Na+] determined from sweat-patch analysis on the same players during an intense practice. Players arrived at the rink in a euhydrated state and drank 0.6 ± 0.1 L of fluid before the game. Mean playing time for the forwards was 18:85 ± 1:15 min:s and playing time for the defense was 24:00 ± 2:46 min:s. Sweat loss was 3.2 ± 0.2 L and exceeded net fluid intake (2.1 ± 0.1 L). Mean BM loss was 1.3% ± 0.3%, with 8/24 players losing between 1.8% to 4.3% BM. Players preferred to drink water and a carbohydrate electrolyte solution before the game and during intermissions, while only water was consumed during each period. Practice mean forehead sweat [Na+] was 74 mmol·L–1. Estimated sweat Na+ losses of 3.1 ± 0.4 g (∼8 g NaCl) coupled with low Na+ intake of 0.8 ± 0.2 g (∼2 g NaCl) resulted in a significant Na+ deficit by the end of the game. This study demonstrated that despite abundant opportunities to hydrate during a hockey game, one-third of the players did not drink enough fluid to prevent sweat losses of 2% BM or higher. Losing 2% BM has been associated with decreases in athletic performance.
How to test maximal oxygen uptake: a study on timing and testing procedure of a supramaximal verification test
Authors: Scharhag-Rosenberger Friederike , Carlsohn Anja , Cassel Michael , Mayer Frank , Scharhag Jürgen
Published: February 2011

Verification tests are becoming increasingly common for confirming maximal oxygen uptake (VO2 max) attainment. Yet, timing and testing procedures vary between working groups. The aims of this study were to investigate whether verification tests can be performed after an incremental test or should be performed on a separate day, and whether VO2 max can still be determined within the first testing session in subjects not satisfying the verification criterion. Forty subjects (age, 24 ± 4 years; VO2 max, 50 ± 7 mL·min–1·kg–1) performed a maximal incremental treadmill test and, 10 min afterwards, a verification test (VerifDay1) at 110% of maximal velocity (vmax). The verification criterion was a VerifDay1 peak oxygen uptake (VO2 peak) ≤5.5% higher than the incremental test value. Subjects not achieving the verification criterion performed another verification test at 115% vmax (VerifDay1′) 10 min later, trying to confirm VerifDay1 VO2 peak as VO2 max. All other subjects exclusively repeated VerifDay1 on a separate day (VerifDay2). Of the 40 subjects, 6 did not satisfy the verification criterion. In 4 of them, attainment of VO2 max was confirmed by VerifDay1′. VO2 peak was equivalent between VerifDay1 and VerifDay2 (3722 ± 991 mL·min–1 vs. 3752 ± 995 mL·min–1, p = 0.56), whereas time to exhaustion was significantly longer in VerifDay2 (2:06 ± 0:22 min:s vs. 2:42 ± 0:38 min:s, p < 0.001, n = 34). The verification test VO2 peak does not seem to be affected by a preceding maximal incremental test. Incremental and verification tests can therefore be performed within the same testing session. In individuals not achieving the verification criterion, VO2 max can be determined by means of a subsequent, more intense verification test in most but not all cases.
New Canadian Physical Activity Guidelines
Authors: Tremblay Mark S. , Warburton Darren E.R. , Janssen Ian , Paterson Donald H. , Latimer Amy E. , Rhodes Ryan E. , Kho Michelle E. , Hicks Audrey , LeBlanc Allana G. , Zehr Lori , Murumets Kelly , Duggan Mary
Published: February 2011

The Canadian Society for Exercise Physiology (CSEP), in cooperation with ParticipACTION and other stakeholders, and with support from the Public Health Agency of Canada (PHAC), has developed the new Canadian Physical Activity Guidelines for Children (aged 5–11 years), Youth (aged 12–17 years), Adults (aged 18–64 years), and Older Adults (aged ≥65 years). The new guidelines include a preamble to provide context and specific guidelines for each age group. The entire guideline development process was guided by the Appraisal of Guidelines for Research Evaluation (AGREE) II instrument, which is the international standard for clinical practice guideline development. Thus, the guidelines have gone through a rigorous and transparent developmental process; we based the recommendations herein on evidence from 3 systematic reviews, and the final guidelines benefitted from an extensive online and in-person consultation process with hundreds of stakeholders and key informants, both domestic and international. Since 2006, the products of our efforts resulted in the completion of 21 peer-reviewed journal articles (including 5 systematic reviews) that collectively guided this work. The process that Canadian researchers undertook to update the national physical activity guidelines represents the most current synthesis, interpretation, and application of the scientific evidence to date.
A simple steel beam design curveWork upon which this paper is based was presented at the 2008 CSCE Annual Conference in Quebec City on 11 June 2008.
Authors: MacPhedran Ian , Grondin Gilbert Y.
Published: February 2011

A simple alternative equation for the calculation of the strength of laterally unbraced structural steel beams is presented herein. This equation uses a format similar to the present steel column design curve in the Canadian structural steel design standard, CAN/CSA-S16-09, and is proposed as a replacement for the existing three part curve for beam strength by a one part equation with a continuous derivative. A reliability analysis of the new equation indicates that the equation provides safety levels very close to those of the current formula for classes 1 and 2 rolled sections. It also provides the desired level of safety for welded beams, whereas the current equations tend to over-estimate their strength. The alternative equation also provides adequate safety for class 3 beams. The concept of maximum unbraced length for braced beam design (Lu) is revisited herein and a simple calculation for this length is also proposed.
Estimation of expected travel time using the method of moment
Authors: Sun Lu , Gu Wenjun , Mahmassani Hani
Published: February 2011

Daily travel time is cast into a framework of nonstationary stochastic process. For a fixed value of departure time in a day, travel time given origin, destination, and route information, is treated as a random variable. For a specific date, travel time is treated as a deterministic function of departure time t. Under this framework, the expected travel time for a given departure time is defined as an ensemble mean travel time (EMTT) over a number of days. The method of moment is proposed to compute EMTT based on a hypothetical piecewise constant speed trajectory for travel time estimation. The advantage of the method of moment for EMTT estimation is that it only requires ensemble mean and ensemble variance of spot speed information at point detectors, which is much easier and cost-effective to get than obtaining collections of massive spot speed data per se. The result is compared against Monte Carlo simulation and direct sampling based simulation. The proposed method of moment approach provides accurate estimation of EMTT (e.g., the expected travel time estimation) under a wide range of traffic conditions (e.g., free flow and congestion).
Incentive genetic algorithm based time–cost trade-off analysis across a build–operate–transfer project concession period
Authors: Li Hongxian , Al-Hussein Mohamed , Lei Zhen
Published: February 2011

The build–operate–transfer (BOT) scheme is widely applied to finance new infrastructure projects with private sector (concessionaire) participation. For a predetermined concession period (CP), assuming that CP consists of the construction duration (CD) and the concession operation period (OP), different construction durations result in different profits for the concessionaire. Meanwhile, according to the time–cost trade-off (TCT) principle, shortening the CD increases the construction cost; shortening the CD also prolongs the OP, which could increase the total benefit of BOT projects. Hence, how to arrange construction reasonably to maximize the whole profit is a key issue for a concessionary. This paper proposes a methodological framework including optimization, sensitivity analysis, and improved (incentive) genetic algorithms (GA) for BOT projects. Through the proposed methodological framework, the reasonable construction duration of a BOT project can be obtained. A numerical example is used to verify the proposed methodology.
Behavior of mine tailings under cyclic hydraulic loading
Authors: Geremew Africa M. , Yanful Ernest K.
Published: February 2011

Shallow water cover is one of the most effective methods of managing sulfide-bearing reactive mine tailings. Unless sufficient water cover depth is provided, surface erosion by wind-induced waves and pressure-driven currents can re-suspend the tailings and expose them to dissolved oxygen and affect the quality of the water cover. The present study gives a simple approach for the estimation of the critical shear stress for surface erosion of mine tailings and cohesive sediments under shallow water cover. Erosion tests were carried out in a Plexiglas laboratory annular column on mine tailings and sediments under a 50 cm water cover. The annular column was 30 cm in diameter, 120 cm in height and had a 9 cm annular flow width. Shear stress was introduced through a motor driven Teflon stirrer to investigate the initiation of motion and subsequent re-suspension of newly deposited mine tailings and sediments. The velocity field and the pressure change in the boundary layer were measured by laser Doppler velocimeter (LDV) and Preston tube, respectively. The ranges of critical shear stress for the tailings and sediments were estimated by the LDV and Preston tube measurements and visual observation. The results showed that the erosion behavior of most of the mine tailings can be explained by a power law erosion equation.
Characterization of the coefficient of thermal expansion and its effect on the performance of Portland cement concrete pavements
Authors: Chung Yoonseok , Shin Hak-Chul
Published: February 2011

The coefficient of thermal expansion (CTE) of concrete is considered to be an important design parameter to predict Portland cement concrete (PCC) pavement performance in mechanistic-empirical pavement design guide (MEPDG). This study measured CTE values of concrete specimens having various coarse aggregates, and investigated the relationship between the CTE and critical design parameters. It was found that aggregate types, the amount of coarse aggregate, and relative humidity (RH) had a statistically significant impact on the CTE. Expansion CTE had a higher variation compared to contraction CTE, and the maximum value of expansion CTE at 63% RH was 8% higher than the value at 100% RH. Sensitivity analysis showed that inaccurate estimation of concrete CTE can cause serious error in predicting the performance of PCC pavements. A prediction equation of concrete CTE was introduced by modifying Hansen’s model and the predicted CTE value had a good agreement with the measured CTE.
Statistical vehicle classification methods derived from girder strains in bridges
Authors: Rutherford Grant , McNeill Dean K.
Published: February 2011

This paper investigates the use of a pre-existing network of resistive strain gauges located on the girders of a single bridge span to determine the classification and estimate the weight of vehicles traveling over that span. Vehicle events on the bridge are identified automatically by a measurement filtering algorithm. Manual classification labels are then applied to a subset of these events to investigate the strain signal features that distinguish various vehicle classes. Trends in these features over time are investigated, and an estimate of vehicle weight is obtained from these features without the need for detailed knowledge of the structure's composition. Additionally, a number of neural network configurations are tested on the problem of determining vehicle class from these features. Results are tested on data from both the summer and winter seasons. Finally, estimates of vehicle weight are improved by using the classification network to filter input events.
Suspended sediment dynamics in a tributary of the Saint John River, New Brunswick
Authors: Higgins Hélène , St-Hilaire André , Courtenay Simon C. , Haralampides Katy A.
Published: February 2011

Historical hydrometeorological and suspended sediment concentration (SSC) data from the Kennebecasis River, a tributary of the Saint John River in New Brunswick, Canada, were investigated to help understand what drives high sediment transport in that system. Analysis of correlation coefficients between SSC and potential drivers at various time steps suggested that multiple regressions would not be optimal for this purpose, and that lagged flow (Q) and precipitation should be taken into account in any model. A frequency analysis involving annual maxima of SSC, Q, and precipitation events revealed there is no systematic unique driver of extreme annual SSC or high annual loads. Finally, artificial neural network (ANN) models were developed to verify whether the variables examined previously would yield better results in a nonlinear context. Network inputs were mean temperature, Q, Q(t–1), Q(t–2), and day-of-year. Using daily loads directly as a target in the network yielded satisfactory results, with 88% of the variance explained by the model and a mean absolute deviation between estimated and real annual loads of 16%. The ANN model systematically outperformed multiple linear regressions.
Activation and function of immediate-early genes in the nervous systemThis paper is one of a selection of papers in a Special Issue entitled 31st Annual International Asilomar Chromatin and Chromosomes Conference, and has undergone the Journal’s usual peer review process.
Authors: Pérez-Cadahía Beatriz , Drobic Bojan , Davie James R.
Published: February 2011

Immediate-early genes have important roles in processes such as brain development, learning, and responses to drug abuse. Further, immediate-early genes play an essential role in cellular responses that contribute to long-term neuronal plasticity. Neuronal plasticity is a characteristic of the nervous system that is not limited to the first stages of brain development but persists in adulthood and seems to be an inherent feature of everyday brain function. The plasticity refers to the neuron’s capability of showing short- or long-lasting phenotypic changes in response to different stimuli and cellular scenarios. In this review, we focus on the immediate-early genes encoding transcription factors (AP-1 and Egr) that are relevant for neuronal responses. Our current understanding of the mechanisms involved in the induction of the immediate-early genes is presented.
Characterization of intronic structures and alternative splicing in Phytophthora sojae by comparative analysis of expressed sequence tags and genomic sequences
Authors: Shen Danyu , Ye Wenwu , Dong Suomeng , Wang Yuanchao , Dou Daolong
Published: February 2011

The oomycetes, a distinct phylogenetic lineage of fungus-like microorganisms, are heterokonts (stramenopiles) belonging to the supergroup Chromalveolata. Although the complete genomic sequences of a number of oomycetes have been reported, little information regarding the introns therein is available. Here, we investigated the introns of Phytophthora sojae , a pathogen that causes soybean root and stem rot, by a comparative analysis of genomic sequences and expressed sequence tags. A total of 4013 introns were identified, of which 96.6% contained canonical splice sites. The P. sojae genome possessed features distinct from other organisms at 5′ splice sites, polypyrimidine tracts, branch sites, and 3′ splice sites. Diverse repeating sequences, ranging from 2 to 10 nucleotides in length, were found at more than half of the intron–exon boundaries. Furthermore, 122 genes underwent alternative splicing. These data indicate that P. sojae has unique splicing mechanisms, and recognition of those mechanisms may lead to more accurate predictions of the location of introns in P. sojae and even other oomycete species.
The polymicrobial nature of airway infections in cystic fibrosis: Cangene Gold Medal LectureThis article is based on a presentation by Dr. Christopher Sibley at the 60th Annual Meeting of the Canadian Society of Microbiologists in Hamilton, Ontario, on 15 June 2010. Dr. Sibley was the recipient of the 2010 Cangene Gold Medal as the Canadian Graduate Student Microbiologist of the Year, an annual award sponsored by Cangene Corporation intended to recognize excellence in graduate research.
Authors: Sibley Christopher D. , Surette Michael G.
Published: February 2011

Microbial communities characterize the airways of cystic fibrosis (CF) patients. Members of these diverse and dynamic communities can be thought of as pathogens, benign commensals, or synergens — organisms not considered pathogens in the traditional sense but with the capacity to alter the pathogenesis of the community through microbe–microbe or polymicrobe–host interactions. Very few bacterial pathogens have been implicated as clinically relevant in CF; however, the CF airway microbiome can be a reservoir of previously unrecognized but clinically relevant organisms. A combination of culture-dependent and culture-independent approaches provides a more comprehensive perspective of CF microbiology than either approach alone. Here we review these concepts, highlight the future challenges for CF microbiology, and discuss the implications for the management of CF airway infections. We suggest that the success of treatment interventions for chronic CF lung disease will rely on the context of the microbes within microbial communities. The microbiology of CF airways may serve as a model to investigate the emergent properties of other clinically relevant microbial communities in the human body.
Genetic diversity of picoeukaryotes in eight lakes differing in trophic status
Authors: Zhao Biying , Chen Meijun , Sun Ying , Yang Jiaxin , Chen Feizhou
Published: February 2011

The genetic diversity of picoeukaryotes (0.2–5.0 µm) was investigated in 8 lakes differing in trophic status in Nanjing, China. Denaturing gradient gel electrophoresis (DGGE) and cloning and sequencing of 18S rRNA genes were applied to analyze the picoeukaryotic communities. DGGE analysis showed that among the 8 lakes, the diversity of picoeukaryotes was greatest in the mesotrophic Lake Nan (24 bands) and least in the oligotrophic Lake Qian (12 bands). Cluster analysis of DGGE profiles revealed that the 8 lakes were grouped into 2 distinct clusters. Cluster 1 contained lakes Mochou, Zixia, Huashen, Nan, Pipa, and Qian, while cluster 2 contained lakes Xuanwu and Baijia. Clone libraries were constructed from the mesotrophic Lake Xuanwu and the oligotrophic Lake Zixia, and the 2 libraries were compared using the program LIBSHUFF. This analysis indicated that the picoeukaryotic community composition differed significantly between the 2 lakes (p = 0.001). A total of 25 operational taxonomic units were detected; 18 (62 clones) were related to known eukaryotic groups, while 7 (30 clones) were not affiliated with any known eukaryotic group. Alveolates and stramenopiles were the dominant groups in Lake Xuanwu, while alveolates and chlorophyta predominated in Lake Zixia. Multivariate statistical analysis indicated that the differences in the picoeukaryotic community composition of the 8 lakes might be related to trophic status and top-down regulation by metazooplankton.
Composition of the bacterial biota in slime developed in two machines at a Canadian paper mill
Authors: Disnard Julie , Beaulieu Carole , Villemur Richard
Published: February 2011

During the process of papermaking by pulp and paper plants, a thick and viscous deposits, termed slime, is quickly formed around the paper machines, which can affect the papermaking process. In this study, we explored the composition of the bacterial biota in slime that developed on shower pipes from 2 machines at a Canadian paper mill. Firstly, the composition was assessed for 12 months by DNA profiling with polymerase chain reaction coupled with denaturing gradient gel electrophoresis. Except for short periods (2–3 months), clustered analyses showed that the bacterial composition of the slime varied substantially over the year, with less than 50% similarity between the denaturing gradient gel electrophoresis profiles. Secondly, the screening of 16S rRNA gene libraries derived from 2 slime samples showed that the most abundant bacteria were related to 6 lineages, including Chloroflexi, candidate division OP10, Clostridiales, Bacillales, Burkholderiales, and the genus Deinococcus . Finally, the proportion of 8 bacterial lineages, such as Deinococcus sp., Meiothermus sp., and Chloroflexi, was determined by the Catalyzed Reporter Deposition – Fluorescence In Situ Hybridization in 2 slime samples. The results showed a high proportion of Chloroflexi, Tepidimonas spp., and Schlegelella spp. in the slime samples.
A putative twin-arginine translocation system in the phytopathogenic bacterium Xylella fastidiosa
Authors: Ciapina Luciane Prioli , Picchi Simone Cristina , Lacroix Jean-Marie , de Macedo Lemos Eliana Gertrudes , Ödberg-Ferragut Carmen
Published: February 2011

The twin-arginine translocation (Tat) pathway of the xylem-limited phytopathogenic bacterium Xylella fastidiosa strain 9a5c, responsible for citrus variegated chlorosis, was explored. The presence of tatA, tatB, and tatC in the X. fastidiosa genome together with a list of proteins harboring 2 consecutive arginines in their signal peptides suggested the presence of a Tat pathway. The functional Tat dependence of X. fastidiosa OpgD was examined. Native or mutated signal peptides were fused to the β-lactamase. Expression of fusion with intact signal peptides mediated high resistance to ampicillin in Escherichia coli tat+but not in the E. coli tat null mutant. The replacement of the 2 arginines by 2 lysines prevented the export of β-lactamase in E. coli tat+, demonstrating that X. fastidiosa OpgD carries a signal peptide capable of engaging the E. coli Tat machinery. RT–PCR analysis revealed that the tat genes are transcribed as a single operon. tatA, tatB, and tatC genes were cloned. Complementation assays in E. coli devoid of all Tat or TatC components were unsuccessful, whereas X. fastidiosa Tat components led to a functional Tat translocase in E. coli TatB-deficient strain. Additional experiments implicated that X. fastidiosa TatB component could form a functional heterologous complex with the E. coli TatC component.
Temporal and spatial interactions between an obligate predator, the Eurasian lynx (Lynx lynx), and a facultative scavenger, the wolverine (Gulo gulo)
Authors: Mattisson Jenny , Persson Jens , Andrén Henrik , Segerström Peter
Published: February 2011

Interspecific interactions between sympatric carnivores can be important for the behaviour and demography of involved species. We studied spatial and temporal interactions between an obligate predator, the Eurasian lynx ( Lynx lynx (L., 1758)), and a facultative scavenger, the wolverine ( Gulo gulo (L., 1758)). Wolverines are known to utilize lynx-killed reindeer ( Rangifer tarandus tarandus (L., 1758)) and may benefit from being sympatric with lynx if interference competition is low. We used individual location data from 9 lynx and 17 wolverines to analyse interaction between inter- and intra-specific dyads (n = 195). We found no spatial segregation between lynx and wolverines and we observed no attraction or avoidance between individuals of the two species, independent of proportion of home-range overlap. This opposed our prediction that wolverines will show direct or delayed attraction to lynx. Wolverines may still benefit by scavenging lynx-killed reindeer while avoiding direct encounters with the lynx. Within species, we found attraction between males and females, increasing with proportion of overlap for lynx. Attraction was also found between consexual lynx, while consexual wolverines showed little home-range overlap (7%–9%) and neutral temporal interaction, indicating territoriality. Individual space use may be more influenced by conspecific interactions than by other species.
Reproductive consequences of migration decisions by Ipswich Sparrows (Passerculus sandwichensis princeps)
Authors: Dale C. A. , Leonard M. L.
Published: February 2011

The costs and benefits associated with migration differ depending on individual decisions regarding the distance to migrate and where to winter. These decisions affect an individual’s winter experience, which may in turn impact reproductive success the following breeding season. We investigated whether winter location influences performance on the breeding grounds in a short-distance migrant, the Ipswich Sparrow ( Passerculus sandwichensis princeps Maynard, 1872), endemic to Sable Island, Nova Scotia, Canada. We used stable hydrogen isotope analysis to infer the winter location of individuals breeding on Sable Island, and investigated whether body condition, timing of breeding initiation, and number and condition of nestlings varied with winter location. Males wintered farther north than females, and males from the northern end of the wintering range were in better condition, established territories earlier, and tended to produce heavier nestlings than those wintering farther south. Conversely, females that wintered farther south had significantly earlier first egg dates than those that wintered farther north. The results of this study suggest that individual decisions about migration distance can impact reproductive success and that optimal winter locations differ between male and female Ipswich Sparrows.
Long-term feeding ecology of Great Black-backed Gulls (Larus marinus) in the northwest Atlantic: 110 years of feather isotope data
Authors: Farmer R. G. , Leonard M. L.
Published: February 2011

Recent changes to the ecology of the northwest Atlantic are affecting feeding relationships at many trophic levels. With declining fish stocks and fewer fisheries discards, generalist birds such as Great Black-backed Gulls ( Larus marinus L., 1758) may shift their diets. To test whether such a change has occurred, we measured stable nitrogen and carbon isotope ratios of flight feathers collected from modern and museum-preserved birds (1896–2006). We then compared trends in isotope ratios with trends in regional fisheries productivity to determine if gull diets and fisheries changes were associated. We found a significant decline in stable nitrogen isotope ratios of feathers over time, indicating that the gulls’ trophic feeding level has decreased by approximately 2.26‰, or 0.82 trophic units. In contrast, we found no significant change in carbon isotope ratios, giving no clear evidence for a shift to more offshore or terrestrial foraging. The declining stable nitrogen ratio was significantly and positively correlated with both regional groundfish captures and regional fisheries trophic level, and was negatively correlated with each of (i) crab captures and (ii) herring, sardine, and anchovy captures. Our study gives evidence for a shift in diets of Great Black-backed Gulls over time and further suggests that these changes may be related to ongoing changes in fisheries.
NEUTRAL KAON PHOTOPRODUCTION AT LNS, TOHOKU UNIVERSITY
Authors:   For the NKS/NKS2 Collaboration, Kaneta M. , Chiga N. , Beckford B. , Ejima M. , Fujii T. , Fujii Y. , Fujibayashi T. , Gogami T. , Futatsukawa K. , Hashimoto O. , Hosomi K. , Hirose K. , Iguchi A. , Kameoka S. , Kanda H. , Kato H. , Kawama D. , Kawasaki T. , Kimura C. , Kiyokawa S. , Koike T. , Kon T. , Ma Y. , Maeda K. , Maruyama N. , Matsumura A. , Miyagi Y. , Miura Y. , Miwa K. , Nakamura S.N. , Nomura H. , Okuyama A. , Ohtani A. , Otani T. , Sato M. , Shichijo A. , Shirotori K. , Takahashi T. , Tamura H. , Taniya N. , Tsubota H. , Tsukada K. , Terada N. , Ukai M. , Uchida D. , Watanabe T. , Yamamoto T. , Yamauchi H. , Yokota K. , Ishikawa T. , Kinoshita T. , Miyahara H. , Nakabayashi T. , Shimizu H. , Suzuki K. , Tamae T. , Terasawa T. , Yamazaki H. , Han Y. C. , Wang T. S. , Sasaki A. , Konno O. , Bydžovský P. , Sotona M.
Published: February 2011

The elementary photo-strangeness production process has been intensively studied based on the high-quality data of the charged kaon channel, γ + p → K+ + Λ(Σ0). However, there had been no reliable data for the neutral kaon channel γ + n → K0 + Λ(Σ0) and the theoretical investigations suffer seriously from the lack of the data. In order to have reliable data for the neutral kaon photo-production data, substantial effort has been made to measure the γ + n → K0 + Λ process in the π+π- decay channel, using a liquid deuterium target and a tagged photon beam (Eγ = 0.8-1.1 GeV ) in the threshold region at the Laboratory of Nuclear Science (LNS), Tohoku University. We have taken exploratory data quite successfully with the use of Neutral Kaon Spectrometer (NKS) at LNS-Tohoku in 2003 and 2004. The data is compared to theoretical models and it indicates a hint that the K0 differential cross section has a backward peak in the energy region. The second generation of the experiment, NKS2, is designed to extend the NKS experiment by considerably upgrading the original neutral kaon spectrometer, fully replacing the spectrometer magnet, tracking detectors and all the trigger counters. The new spectrometer NKS2 has significantly larger acceptance for neutral kaons compared with NKS, particularly covering forward angles and much better invariant mass resolution. The estimated acceptance of NKS2 is three (ten) times larger for [Formula: see text] than that of NKS. The spectrometer is newly constructed and installed at the Laboratory of Nuclear Science, Tohoku University in 2005. The deuterium target data was taken with tagged photon beam in 2006-2007. We will report recent results of NKS2 in this paper. Additionally, a status of the upgrade project that gives us larger acceptance and capability of K0 + Λ coincidence measurement will be presented.
CURRENT STATUS OF THE G0 PARITY VIOLATION EXPERIMENT CARRIED OUT AT JEFFERSON LABORATORY
Authors:   For the G0 Collaboration, Bimbot L.
Published: February 2011

Among experiments looking for strangeness in nuclear systems, electron scattering Parity-Violation (PV) type experiments aim mainly at measuring the strange quark contributions to the form factors of the proton. They can be accessed by measuring the asymmetry in longitudinally polarized electron elastic scattering. The PV asymmetry is measured at the 10-7 level of accuracy, and when combined with the electromagnetic form factors of the nucleon, the strange form factors can be determined. The full separation of form factors according to quark flavour requires measurements at forward angles on hydrogen and at backward angles on hydrogen and deuterium. The experimental setup used for G 0 in the two different configurations is described. The status of the analysis and the current results are presented and discussed in relation with other experiments past and planned. A few comments are also made regarding some other aspects of physics accessible in simultaneous measurements: neutral currents in N Δ transitions, parity violation in inclusive π- production and 2γ contributions to elastic scattering.
LAMBDA AND ANTI-LAMBDA HYPERNUCLEI IN RELATIVISTIC MEAN-FIELD THEORY
Authors: Song C. Y. , Yao J. M. , Lü H. F. , Meng J.
Published: February 2011

Several aspects about Λ-hypernuclei in the relativistic mean field theory, including the effective Λ-nucleon coupling strengths based on the successful effective nucleon-nucleon interaction PK1, hypernuclear magnetic moment and [Formula: see text]-hypernuclei, have been presented. The effect of tensor coupling in Λ-hypernuclei and the impurity effect of [Formula: see text] to nuclear structure have been discussed in detail.
THE SEARCH FOR ANTIKAON NUCLEAR BOUND STATES, RECENT RESULTS FROM FINUDA
Authors:   For the FINUDA Collaboration, Piano S. , Grion N. , Bonifazi E. , Bregant M. , Camerini P. , Rui R. , Botta E. , Bressani T. , Bufalino S. , De Mori F. , Marcello S. , Calvo D. , Feliciello A. , Filippi A. , Wheadon R. , Busso L. , Morra O. , Agnello M. , Benussi L. , Bertani M. , Fabbri F.L. , Gianotti P. , Hartmann O. , Lucherini V. , Pace E. , Pompili F. , Andronenkov A. , Palomba M. , Pantaleo A. , Paticchio V. , Dalena B. , D'Erasmo G. , Fiore E. M. , Simonetti G. , Lenti V. , Bonomi G. , Zenoni A. , Fontana A. , Genova P. , Panzarasa A. , Montagna P. , Fujioka H. , Nagae T. , Outa H. , Sekimoto M. , Toyoda A. , Maruta T. , Bhang H. C. , Kang B. , Nakajima D. , Mirfakhrai N. , Beer G. , Sanchez Lorente A.
Published: February 2011

Novel data from the [Formula: see text] absorption reaction in light nuclei are presented. The data were collected by the FINUDA spectrometer running at the DAΦNE ϕ-facility, Laboratori Nazionali di Frascati (LNF), Italy.
SEARCH FOR ppK- WITH PROTON INDUCED REACTIONS AT GSI
Authors:   For the FOPI Collaboration, Fabbietti L.
Published: February 2011

Several experiments engaging kaon beams have been carried out to study the existence of deeply bound kaonic state. We proposed an alternative method, which exploits a p + p reaction at 3.5 GeV incoming energy to search for the most elementary of the kaonic states: ppK-. This experiment is planned with the FOPI spectrometer at GSI and a silicon-based trigger system has been developed to increase the detection capability of the existing system for the reaction of interest. Several tests have been performed under realistic beam conditions to test the feasibility of the measurement and the proof of principle of the trigger system. The positive results of such measurements are shown in this contribution together with the expected rates extracted from simulations.
VARIATIONAL CALCULATION OF K-pp WITH CHIRAL SU(3)-BASED $\bar KN$ INTERACTION
Authors: Doté A. , Hyodo T. , Weise W.
Published: February 2011

The prototype of a [Formula: see text] nuclear cluster, K-pp, has been investigated using effective [Formula: see text] potentials based on chiral SU (3) dynamics. Variational calculation shows a bound state solution with shallow binding energy B(K-pp) = 20 ± 3 MeV and broad mesonic decay width [Formula: see text]. The [Formula: see text] pair in the K-pp system exhibits a similar structure as the Λ(1405). We have also estimated the dispersive correction, p-wave [Formula: see text] interaction, and two-nucleon absorption width.
STATISTICAL DECAY OF EXCITED ΛΛ HYPERNUCLEI AND γ-SPECTROSCOPY AT $\rm \bar P \rm ANDA$
Authors: Lorente A. Sanchez , Pochodzalla J. , Botvina A.
Published: February 2011

Hypernuclear physics is currently attracting renewed attention. Thanks to the use of stored [Formula: see text] beams, copious production of double Λ hypernuclei is expected at the [Formula: see text] experiment which will enable high precision γ-spectroscopy of such nuclei for the first time. In the present work we have studied the population of particle stable, excited states in double hypernuclei after the capture of a Ξ- within a statistical decay model. In order to check the feasibility of producing and performing γ-spectroscopy of double hypernuclei at [Formula: see text], an event generator based on these calculations has been implemented in the [Formula: see text] simulation framework PANDAROOT.
ORBIFOLD CUP PRODUCTS AND RING STRUCTURES ON HOCHSCHILD COHOMOLOGIES
Authors: PFLAUM M. J. , POSTHUMA H. B. , TANG X. , TSENG H.-H.
Published: February 2011

In this paper, we study the Hochschild cohomology ring of convolution algebras associated to orbifolds, as well as their deformation quantizations. In the first case, the ring structure is given in terms of a wedge product on twisted polyvectorfields on the inertia orbifold. After deformation quantization, the ring structure defines a product on the cohomology of the inertia orbifold. We study the relation between this product and an S1-equivariant version of the Chen–Ruan product. In particular, we give a de Rham model for this equivariant orbifold cohomology.
INVARIANTS FOR LEGENDRIAN KNOTS IN LENS SPACES
Authors: LICATA JOAN E.
Published: February 2011

In this paper, we define invariants for primitive Legendrian knots in lens spaces L(p, q), q ≠ 1. The main invariant is a differential graded algebra [Formula: see text] which is computed from a labeled Lagrangian projection of the pair (L(p, q), K). This invariant is formally similar to a DGA defined by Sabloff which is an invariant for Legendrian knots in smooth S1-bundles over Riemann surfaces. The second invariant defined for K ⊂ L(p, q) takes the form of a DGA enhanced with a free cyclic group action and can be computed from a cyclic cover of the pair (L(p, q), K).