bluuebunny/crossref_metadata_2025 huggingface dataset:
Transit Referenda and Funding Options
Authors: Dixit Vinayak , Rutstrom Elisabet E. , Mard Michael Seph , Zielske Ryan O.
Published: October 2010

Transit is an integral part of a sustainable transportation system in any region. Proposals for transit initiatives that are brought to referenda include a funding vehicle, either tax based or bond based. A tax-funded proposal imposes the cost on the present generation of residents, whereas a bond-funded proposal delays the burden to future generations. The aim is to investigate whether the success of proposals in referenda is related to the use of taxes or bonds for funding. This question is investigated with the use of data from 111 transit referenda held in the United States from 1999 to 2007. It was found that proposals that use taxes for funding are less likely to pass than those that use bonds.
Reliability Improvement in Short Headway Transit Services
Authors: van Oort Niels , Wilson Nigel H. M. , van Nes Rob
Published: October 2010

Improving service reliability is becoming a key focus for most public transport operators. One common operational strategy is holding. Holding vehicles can improve reliability, resulting in shorter travel times and less crowding. In this paper both schedule-based and headway-based holding strategies in short headway services are analyzed. Despite significant attention to holding in the current literature, some important aspects were not previously researched. The main new variables are maximum holding time, reliability buffer time, and, in the case of schedule-based holding, percentile value used to design the schedule. A real line in the Hague (Tram Line 9), Netherlands, and hypothetical lines are analyzed with various levels of running time variability. Headway-based and schedule-based holding have the largest effect if deviations are high. When schedule-based holding is applied with a maximum of 60-s holding time, the optimal value of the percentile value becomes about 65% for all lines analyzed. When no maximum holding time is applied, schedule-based holding is more effective; there is no difference when the maximum holding time is set to 60 s. This research also shows the effect of holding on crowding: an average level of irregularity of 20% could decrease to 15%, enabling either smaller capacity slack or less crowding.
Service Reliability Measurement Using Automated Fare Card Data
Authors: Uniman David L. , Attanucci John , Mishalani Rabi G. , Wilson Nigel H. M.
Published: October 2010

This paper explores the potential of using automated fare card data to quantify the reliability of service as experienced by passengers of rail transit systems. The distribution of individual passenger journey times can be accurately estimated for those systems requiring both entry and exit fare card validation. With the use of this information, a set of service reliability measures is developed that can be used to routinely monitor performance, gain insights into the causes of unreliability, and serve as an input into the evaluation of transit service. An estimation methodology is proposed that classifies performance into typical and nonrecurring conditions, which allows analysts to estimate the level of unreliability attributable to incidents. The proposed measures are used to characterize the reliability of one line in the London Underground under typical and incident-affected conditions with the use of data from the Oyster smartcard system for the morning peak period. A validation of the methodology with the use of incident-log data confirms that a large proportion of the unreliability experienced by passengers can be attributed to incident-related disruptions. In addition, the study revealed that the perceived reliability component of the typical Underground trip exceeds its platform wait time component and equals about half of its on-train travel time as well as its station access and egress time components, suggesting that sizable improvements in overall service quality can be attained through reliability improvements.
Anxiety-Based Formulation to Estimate Generalized Cost of Transit Travel Time
Authors: Nour Akram , Casello Jeffrey M. , Hellinga Bruce
Published: October 2010

This paper examines the effect of unreliable transit service on transit user costs with the goal of increasing the accuracy of mode choice models. The concept advanced here is to include explicitly in the formulation of mode choice models the anxiety experienced by passengers when service is unreliable because of late departure or longer-than-expected in-vehicle travel time. This anxiety is modeled as a generalized cost penalty that is added to actual in-vehicle time. The magnitude of the penalty depends on travelers’ assessment of the likelihood of arriving on time at their destination. It is believed that this formulation of anxiety is behaviorally representative. To test the effects of the formulation, a simulation model is generated that quantifies the anxiety component of generalized cost for 10,000 travelers with various aversions to risk for travel between station pairs with different observed reliabilities. Results suggest that primarily for risk-averse travelers, but also for other classes, anxiety may constitute a high percentage of total generalized cost, which may explain many travelers’ unwillingness to choose transit in cases in which deterministic models suggest that they will. Calibrating a model of this type presents substantial challenges. An approach is introduced that is currently being pursued to gather actual anxiety levels as a function of transit travel reliability. The paper concludes with comments on future research directions.
Exploring Potential Inequities between Burdens and Benefits of Climate Change Abatement Policies
Authors: Golub Aaron , Kelley Jason
Published: October 2010

Although the connection between the storms along the coast of the Gulf of Mexico in 2005 and global climate change is still being debated, the fact that low-income communities are more likely to bear the greatest burden and are more vulnerable to potential future climate change and rising sea levels is widely acknowledged. Adding to this problem, greenhouse gas emissions that contribute to global warming are income dependent: people with the highest incomes, both globally and within specific communities, tend to pollute more than those with the lowest incomes. A policy dilemma thus arises when abatement strategies involve regressive financing or when the benefits of such strategies are concentrated within higher-income groups. Low-income communities are in effect subsidizing the pollution abatement of higher-income communities. This paper reviews a range of evidence showing the unequal vulnerabilities, responsibilities, benefits, and costs from climate change and climate change policies. A framework for the evaluation of climate change mitigation strategies in the transportation sector is then proposed. This framework incorporates these equity issues along with other traditional measures of policy effectiveness. Exactly how these various inequities are incorporated and valued is highly case specific and is proposed as the subject of future research.
Green Credits versus Environmentally Sustainable Traffic Operations
Authors: Zhou Yan , Tupper Lee , Chowdhury Mashrur , Klotz Leidy
Published: October 2010

Although society is facing a variety of environmental issues, including the depletion of energy resources, and has a much greater awareness of climate change and its serious related social impacts, transportation systems have been pushed to increasingly greater limits because of the dramatic growth in traffic demand. A case study was performed to compare the contributions of green construction credits and those of environmentally sustainable traffic operations to reducing energy use and emissions. The study measured the impacts of green credits by using the Carnegie Mellon University economic input–output life-cycle assessment model. These impacts were compared with those achieved through sustainable traffic operation strategies, consisting of a high-occupancy vehicle lane and access to public transit. The study shows that the energy and emissions reductions obtained by use of the traffic operation strategies eclipsed those obtained by use of the green credit measures in just 1 month of traffic operations. The carbon dioxide emissions created and the total energy consumed by only 1 month of traffic were three times greater and 30% more, respectively, than those obtained by repaving the same roadway. In addition to reducing emissions, environmentally sustainable traffic operations offer social sustainability benefits, such as reducing traffic delays and improving flow, which reduce the demand for transportation infrastructure and which can ultimately reduce the need for new roadway construction. Although both green credit measures and environmentally sustainable traffic operations are essential to true sustainability, the relative impacts of both traffic operations and construction credits should be considered when research and infrastructure investments are prioritized.
Environmental Efficiency Model Based on Data Envelopment Analysis and Its Application to Environmentally Sustainable Transport Policies
Authors: Yoshino Daisuke , Fujiwara Akimasa , Zhang Junyi
Published: October 2010

To realize environmentally sustainable transport (EST), it becomes more and more important to reduce the environmental load from the transport sector while maintaining the level of mobility. Because mobility policies often conflict with environmental ones, policy decision makers need to find a way to solve the exclusiveness between these two policies. This study attempts to apply the concept of ecoefficiency, originally proposed by the World Business Council for Sustainable Development, to tackle the dilemma between urban mobility and environmental load in cities in both developed and developing countries. This study proposes a new model, the environmental efficiency (EE) model, which expands the concept of the data envelopment analysis cost-efficiency model. This new model aims to measure the efficiency of energy consumption at a given level of mobility in each transport system by incorporating some feasible conditions. In addition, the model can find multiple sets of frontier cities that are the most efficient among homogeneously developed cities. Consequently, the proposed method contributes to providing each city with a feasible transport energy consumption goal. Moreover, a panel analysis was carried out to examine temporal changes in environmental efficiency. Finally, the effects of some EST policies implemented to raise efficiency are simulated on the basis of the EE model, including modal shifts in a city, technological innovations to improve the intensity of energy consumption in cities, and the emissions trading scheme between cities in developing and developed countries. The method is confirmed to be a useful tool for the establishment of more plausible targets for transport energy-saving policies.
An integrated lightweight ice-penetrating radar system
Authors: Mingo Laurent , Flowers Gwenn E.
Published: October 2010

We describe a portable low-frequency impulse radar system intended for ground-based surveys that employs off-the-shelf hardware integrated with custom-designed software. The hardware comprises a 1–200 MHz transmitter, digitizer, computer and GPS receiver, which together weigh ∼1.5 kg. The entire system, including waterproof enclosures and batteries suited for >8 hours of continuous operation, weighs <10 kg plus the weight of the antenna housing. The system design is flexible, permitting hardware components such as the digitizer or navigation device to be exchanged. The software includes acquisition parameter control, real-time visual ice-depth rendering and data management capabilities using a hierarchical data format. The system described here has been successfully used to sound polythermal ice up to ∼220 m thick in ski-based surveys in the Yukon, Canada, and temperate ice up to ∼550 m thick in machine-based surveys in Iceland.
Seasonal variability in the dynamics of marine-terminating outlet glaciers in Greenland
Authors: Howat Ian M. , Box Jason E. , Ahn Yushin , Herrington Adam , McFadden Ellyn M.
Published: October 2010

Recent studies indicate that the dynamics of fast-flowing, marine-terminating outlet glaciers of the Greenland ice sheet may be sensitive to climate and ocean forcing on sub-annual timescales. Observations of seasonal behavior of these glaciers at such high temporal resolution, however, are currently few. Here we present observations of front position, flow speed, near-surface air temperature and ocean conditions for six large marine-terminating glaciers in the Uummannaq region of West Greenland, to investigate controls on short-term glacier dynamics. As proposed by other studies, we find that seasonal front advance and retreat correlates with the formation and disappearance of an ice melange. Our data suggest that high sea-surface temperature, anomalously low sea-ice concentration and reduced melange formation in early 2003 have triggered multi-year retreat of several glaciers in the study area, which is consistent with other regions in Greenland. Of the stable glaciers, only Rink Isbræ exhibits a seasonal speed variation that correlates with variations in front position, with the others undergoing mid-summer deceleration that indicates the effects of subglacial meltwater discharge and drainage system evolution. Drainage of supraglacial lakes and water-filled crevasses results in substantial decreases in speed (40–60%) on fast-flowing glaciers. Our results demonstrate that attempts to model ice-sheet evolution must take into account short-timescale flow dynamics resulting from drainage events and oceanographic conditions.
Slow drag in wet-snow avalanche flow
Authors: Sovilla B. , Kern M. , Schaer M.
Published: October 2010

We report impact pressures exerted by three wet-snow avalanches on a pylon equipped with piezoelectric load cells. These pressures were considerably higher than those predicted by conventional avalanche engineering guidelines. The time-averaged pressure linearly increased with the immersion depth of the load cells and it was about eight times larger than the hydrostatic snow pressure. At the same immersion depth, the pressures were very similar for all three avalanches and no dependency between avalanche velocity and pressure was apparent. The pressure time series were characterized by large fluctuations. For all immersion depths and for all avalanches, the standard deviations of the fluctuations were, on average, about 20% of the mean value. We compare our observations with results of slow-drag granular experiments, where similar behavior has been explained by formation and destruction of chain structures due to jamming of granular material around the pylon, and we propose the same mechanism as a possible microscale interpretation of our observations.
Temporal and spatial variation of stable-isotope ratios and accumulation rates in the hinterland of Neumayer station, East Antarctica
Authors: Fernandoy Francisco , Meyer Hanno , Oerter Hans , Wilhelms Frank , Graf Wolfgang , Schwander Jakob
Published: October 2010

Four firn cores were retrieved in 2007 at two ridges in the area of the Ekström Ice Shelf, Dronning Maud Land, coastal East Antarctica, in order to investigate the recent regional climate variability and the potential for future extraction of an intermediate-depth core. Stable water-isotope analysis, tritium content and electrical conductivity were used to date the cores. For the period 1981–2006 a strong and significant correlation between the stable-isotope composition of firn cores in the hinterland and mean monthly air temperatures at Neumayer station was (r = 0.54−0.71). No atmospheric warming or cooling trend is inferred from our stable-isotope data for the period 1962–2006. The stable-isotope record of the ice/firn cores could expand well beyond the meteorological record of the region. No significant temporal variation of accumulation rates was detected. However, decreasing accumulation rates were found from coast to hinterland, as well as from east (Halvfarryggen) to west (Søråsen). The deuterium excess (d) exhibits similar differences (higher d at Søråsen, lower d at Halvfarryggen), with a weak negative temporal trend on Halvfarryggen (0.04‰ a−1), probably implying increasing oceanic input. We conclude that Halvfarryggen acts as a natural barrier for moisture-carrying air masses circulating in the region from east to west.
Rate-effect experiments on round-tipped penetrometer insertion into uniform snow
Authors: Floyer James A. , Bruce Jamieson J.
Published: October 2010

Snow penetrometers are being developed to detect stratigraphy indicative of slab avalanches. Results are presented here from experiments performed to assess the relationship between the velocity of a round-tipped penetrometer through uniform snow and the resulting force response. The range of velocities used is commensurate with that used to drive a manually driven penetrometer through the snow. A characteristic spike is noted in profiles during the initial stage of deformation, which appears to be more pronounced for the harder snow layers tested. An investigation of snow deformation using video analysis of a split-axis rod deforming snow against a clear plastic window indicates that the spike in the force signal corresponds to the development of a compaction zone below the penetrometer tip. Once shear forces that develop in the compacted snow are overcome, deformation proceeds in a steady state and there is little or no relationship between the force response and velocity over the velocity range of our experiments.
Long-term avalanche hazard assessment with a Bayesian depth-averaged propagation model
Authors: Eckert N. , Naaim M. , Parent E.
Published: October 2010

While performing statistical–dynamical simulations for avalanche predetermination, a propagation model must reach a compromise between precise description of the avalanche flow and computation times. Crucial problems are the choice of appropriate distributions describing the variability of the different inputs/outputs and model identifiability. In this study, a depth-averaged propagation model is used within a hierarchical Bayesian framework. First, the joint posterior distribution is estimated using a sequential Metropolis–Hastings algorithm. Details for tuning the estimation algorithm are provided, as well as tests to check convergence. Of particular interest is the calibration of the two coefficients of a Voellmy friction law, with model identifiability ensured by prior information. Second, the point estimates are used to predict the joint distribution of different variables of interest for hazard mapping. Recent developments are employed to compute pressure distributions taking into account the rheology of snow. The different steps of the method are illustrated with a real case study, for which all possible decennial scenarios are simulated. It appears that the marginal distribution of impact pressures is strongly skewed, with possible high values for avalanches characterized by low Froude numbers. Model assumptions and results are discussed.
Should We Aim for Consensus?
Authors: Beatty John , Moore Alfred
Published: October 2010

There can be good reasons to doubt the authority of a group of scientists. But those reasons do not include lack of unanimity among them. Indeed, holding science to a unanimity or near-unanimity standard has a pernicious effect on scientific deliberation, and on the transparency that is so crucial to the authority of science in a democracy. What authorizes a conclusion is the quality of the deliberation that produced it, which is enhanced by the presence of a non-dismissible minority. Scientists can speak as one in more ways than one. We recommend a different sort of consensus that is partly substantive and partly procedural. It is a version of what Margaret Gilbert calls “joint acceptance”–we call it “deliberative acceptance.” It capitalizes on there being a persistent minority, and thereby encourages accurate reporting of the state of agreement and disagreement among deliberators.
Group Justification in Science
Authors: Rolin Kristina
Published: October 2010

An analysis of group justification enables us to understand what it means to say that a research group is justified in making a claim on the basis of evidence. I defend Frederick Schmitt's (1994) joint account of group justification by arguing against a simple summative account of group justification. Also, I respond to two objections to the joint account, one claiming that social epistemologists should always prefer the epistemic value of making true judgments to the epistemic value of maintaining consistency, and another one claiming that the notion of joint commitment implicit in the joint account is epistemically unacceptable.
Assessing a Template Matching Approach for Tree Height and Position Extraction from Lidar-Derived Canopy Height Models of Pinus Pinaster Stands
Authors: Pirotti Francesco
Published: October 2010

In this paper, an assessment of a method using a correlation filter over a lidar-derived digital canopy height model (CHM) is presented. The objective of the procedure is to obtain stem density, position, and height values, on a stand with the following characteristics: ellipsoidal canopy shape (Pinus pinaster), even-aged and single-layer structure. The process consists of three steps: extracting a correlation map from CHM by applying a template whose size and shape resembles the canopy to be detected, applying a threshold mask to the correlation map to keep a subset of candidate-pixels, and then applying a local maximum filter to the remaining pixel groups. The method performs satisfactorily considering the experimental conditions. The mean tree extraction percentage is 65% with a coefficient of agreement of 0.4. The mean absolute error of height is ~0.5 m for all plots except one. It can be considered a valid approach for extracting tree density and height in regularly spaced stands (i.e., poplar plantations) which are fundamental for extracting related forest parameters such as volume and biomass.
Identification of Carbohydrate Metabolism Genes in the Metagenome of a Marine Biofilm Community Shown to Be Dominated by Gammaproteobacteria and Bacteroidetes
Authors: Edwards Jennifer L. , Smith Darren L. , Connolly John , McDonald James E. , Cox Michael J. , Joint Ian , Edwards Clive , McCarthy Alan J.
Published: October 2010

Polysaccharides are an important source of organic carbon in the marine environment and degradation of the insoluble and globally abundant cellulose is a major component of the marine carbon cycle. Although a number of species of cultured bacteria are known to degrade crystalline cellulose, little is known of the polysaccharide hydrolases expressed by cellulose-degrading microbial communities, particularly in the marine environment. Next generation 454 Pyrosequencing was applied to analyze the microbial community that colonizes and degrades insoluble polysaccharides in situ in the Irish Sea. The bioinformatics tool MG-RAST was used to examine the randomly sampled data for taxonomic markers and functional genes, and showed that the community was dominated by members of the Gammaproteobacteria and Bacteroidetes. Furthermore, the identification of 211 gene sequences matched to a custom-made database comprising the members of nine glycoside hydrolase families revealed an extensive repertoire of functional genes predicted to be involved in cellulose utilization. This demonstrates that the use of an in situ cellulose baiting method yielded a marine microbial metagenome considerably enriched in functional genes involved in polysaccharide degradation. The research reported here is the first designed to specifically address the bacterial communities that colonize and degrade cellulose in the marine environment and to evaluate the glycoside hydrolase (cellulase and chitinase) gene repertoire of that community, in the absence of the biases associated with PCR-based molecular techniques.
Proteomic Serum Biomarkers and Their Potential Application in Cancer Screening Programs
Authors: Huijbers Anouck , Velstra Berit , Dekker Tim J. A. , Mesker Wilma E. , Burgt Yuri E. M. van der , Mertens Bart J. , Deelder André M. , Tollenaar Rob A. E. M.
Published: October 2010

Early diagnosis of cancer is of pivotal importance to reduce disease-related mortality. There is great need for non-invasive screening methods, yet current screening protocols have limited sensitivity and specificity. The use of serum biomarkers to discriminate cancer patients from healthy persons might be a tool to improve screening programs. Mass spectrometry based proteomics is widely applied as a technology for mapping and identifying peptides and proteins in body fluids. One commonly used approach in proteomics is peptide and protein profiling. Here, we present an overview of profiling methods that have the potential for implementation in a clinical setting and in national screening programs.
N,N'-{1,3-Phenylenebis[methyleneoxy-2,1-phenylene(Z)methylylidene]}bis[1-(1-naphthyl)methanamine]
Authors: George Lucy A. , Bertolo Emilia , Lodeiro Carlos
Published: October 2010

A new fluorescent di-imine compound containing two naphthalene groups has been synthesized by classical Schiff-base reaction between 2,2’-[1,3-phenylene­bis­(methyleneoxy)]dibenzaldehyde and 1-naphthylmethylamine. The new bischromophoric compound has been characterised by IR, NMR and MALDI-TOF MS spectroscopy. The photophysical characterization was carried out by UV-vis and fluorescence emission spectroscopy, using chloroform. The monomer and excimer bands, typical for the naphthalene in solution, are present in the emission spectra for the compound.
Sense of Place, Community, and Nature Management in Ogasawara, Japan: Investigating the Obeikei Narrative
Authors: Cunningham Paul A.
Published: October 2010

Multidisciplinary place studies are reviewed in order to provide a theoretical foundation on which to examine the Obeikei narrative, especially those who lived through the US Navy era (1945–1968) and who are now struggling to find their footing within the local community.
The Obeikei sense of place and community are explored in terms of “getting by” within the Japanese hegemonic space, and “let nature be” within the discourse of nature management. The US Navy era was found to have a strong impact on the individual and collective
identities of the Obeikei, given the unrestricted ecological encounters it allowed and the sociocultural values that emerged and formed the basis of everyday life and sense of community at this time. An examination of the Obeikei narrative provides insight into their attitudes
towards nature, and why they have been reluctant to participate in the ecotourism project under way at this location—currently vying for World Heritage listing.
Promoting Norway Abroad: A Content Analysis of Photographic Messages of Nature-Based Tourism Experiences
Authors: Vespestad May Kristin
Published: October 2010

Growing interest in tourism experiences is evident in the tourism industry. The concern with creating memorable experiences is an area of increasing importance for both the industry and researchers alike. The focus within the experience economy to date has been on culturally derived
experiences, whereas the ones based on natural resources have been more scarcely debated. To maintain a position in the international tourism market, there is clearly a need to develop promotion strategies that will attract the attention of the increasing market of nature-based tourists. The
intent of this study is to compare how Norwegian nature-based tourism experiences are visually communicated towards two international markets. The visual aspect of promotion is addressed by analyzing and comparing photographs used in brochures and on websites, directed at the Russian and the
British market. As a result of the literature review a matrix is introduced as a framework for further research on photographic messages. The content analysis of the photographs shows minor differences in the way the Russian and British market is addressed, demonstrating that the analyzed
material is nearly standardized. Tangible attributes are emphasized as well as natural features of landscape. The article adds to existing literature as it provides a framework, within which to study promotion and perceptions of photographic messages. Furthermore, the article contributes to
increased knowledge on how nature-based tourism is advertised.
Ploidy‐specific interactions of three host plants with arbuscular mycorrhizal fungi: Does genome copy number matter?
Authors: Sudová Radka , Rydlová Jana , Münzbergová Zuzana , Suda Jan
Published: October 2010

•Premise of the study: Polyploidy has been shown to affect different plant traits and modulate interactions between plants and other organisms, such as pollinators and herbivores. However, no information is available on whether it can also shape the functioning of mycorrhizal symbiosis.

•Methods: The mycorrhizal growth response was assessed for three angiosperms with intraspecific ploidy variation. Different cytotypes ofAster amellus,Campanula gentilis, andPimpinella saxifragawere either left uninoculated or were inoculated with arbuscular mycorrhizal (AM) fungi in a pot experiment. After 3 mo of cultivation in a greenhouse, plant growth, phosphorus concentration in the shoot biomass, and development of the AM symbiosis were evaluated.

•Key results: No significant ploidy‐specific differences in AM development were recorded. The inoculation led to consistently greater phosphorus uptake; however, the effect on plant growth differed considerably among plant species, populations, ploidy levels, and AM species. A salient ploidy‐specific response was observed inA. amellus. Whereas diploid plants benefited from AM inoculation, the hexaploids consistently showed negative or no‐growth responses (depending on the AM species). In contrast toA. amellus, no interactions between inoculation and ploidy were observed inC. gentilisandP. saxifraga.

•Conclusions: The first evidence is provided of a ploidy‐specific response of a mycotrophic plant to AM fungi. Our results demonstrate the complexity of interaction between plants and associated AM fungi, with the ploidy level of the host plant being one component that may modulate the functioning of the symbiosis.
Optimized genotyping with microsatellite markers in the fungal banana pathogen Mycosphaerella fijiensis (Mycosphaerellaceae)
Authors: Robert Stéphanie , Rieux Adrien , Argout Xavier , Carlier Jean , Zapater Marie‐Françoise
Published: October 2010

• Premise of the study: Large‐scale population genetics studies are required to investigate the dispersal processes underlying the emergence of Mycosphaerella fijiensis, a fungal pathogen of banana. To this end, we have developed an optimized genotyping procedure combining novel microsatellite markers and a modified DNA extraction protocol.

• Methods and Results: Primers for tetranucleotide loci were designed directly from the recently published genome sequence of M. fijiensis. A total of 19 new polymorphic and easy‐to‐score markers were developed. Their use was combined with an adapted protocol for total DNA extraction starting from young lesions collected from banana leaves, thus avoiding a pathogen isolation step.

• Conclusions: The combination of the two technical developments presented here will permit the expansion of genotyping capacity in M. fijiensis, allowing large‐scale analysis of samples from various geographic locations.
LOW-INTENSITY ULTRASOUND INCREASES THE ENDOTHELIAL NITRIC OXIDE SYNTHASE (eNOS) EXPRESSION OF ENDOTHELIAL CELLS POSSIBLY VIA THE PHOSPHATIDYLINOSITOL 3-KINASE/AKT/PROTEIN KINASE A SIGNALING PATHWAY
Authors: Hsu Shan-hui , Huang Tsung-Bin , Wang Kuan-Pu
Published: October 2010

The stimulative effects and the associated mechanism of low-intensity ultrasound on endothelial cells were investigated in this study. Human umbilical cord endothelial cells (HUVECs) were exposed to 1 MHz pulsed ultrasound at 34 mW/cm2for 10 min daily. The cell proliferation, nitric oxide release, intracellular calcium concentration, and endothelial nitric oxide synthase (eNOS) gene and protein expressions after ultrasound exposure were analyzed. It was found that ultrasound exposure did not change the cell proliferation, but it enhanced the release of nitric oxide and Ca2+ions, and increased the eNOS activity. The induced phosphorylation of eNOS (Ser1177) by the ultrasound exposure was inhibited by the addition of N-[2-(p-bromocinnamylamino) ethyl]-5-isoquinoline sulfonamide (H89, a protein kinase A inhibitor), but not 2-(4-morpholino)-8-phenyl-4H-1-benzopyran-4-one hydrochloride (LY294002, a phosphoatidylinositol 3-kinase inhibitor). The induced phosphorylation of Akt (protein kinase B, Ser473) by the ultrasound exposure was inhibited by the addition of LY294002, but not by the presence of H89. The results also applied to bovine carotid artery endothelial cells (BAECs) exposed to ultrasound at a larger intensity (68 mW/cm2). The above experiments suggested that low-intensity ultrasound may promote eNOS activity of endothelial cells via the phosphatidylinositol 3-kinase/Akt/protein kinase A signaling pathway. This may have implications on the therapeutic effect of ultrasound in tissue repair.
A FREQUENCY SIGNAL METHOD FOR fMRI DATA ANALYSIS
Authors: Zhang Jiang , Chen Huafu , Fang Fang , Liu Hualin , Liao Wei
Published: October 2010

Currently, all the data processing strategies for functional magnetic resonance imaging (fMRI) utilize temporal informationpaying little attention to or totally ignoring frequency information. In this paper, a new method is proposed to detect the functional activation regions in the brain by using the frequency information of fMRI time series. The main idea is that the frequency entropy information (FEI) difference of fMRI data between task and control states is specified as brain activation index. The validity of the proposed FEI approach is confirmed by analyzing the result of the simulated synthesized data. Additionally, the comparison of receiver operating characteristic (ROC) curves acquired respectively from the proposed scheme, the statistical parametric mapping (SPM), and the Support Vector Machine (SVM) methods of fMRI data analysis indicate an obvious superiority of the former. In vivo fMRI studies of subjects with event-related experiment reveal that FEI method can enable the effective detection of brain functional activation.
BIOMECHANICAL TESTING PROCEDURES IN TENDON GRAFT RECONSTRUCTIVE ACL SURGERY
Authors: Chizari Mahmoud , Wang Bin , Barrett Mel , Snow Martyn
Published: October 2010

This paper, describes the biomedical testing of an Anterior Cruciate Ligament (ACL) reconstruction using an interference screw fixation on the bovine and porcine tissues. The harvesting procedure, experimental setup, mechanical testing, and evaluation of the tendon graft interference screw fixation are all presented throughout this study. A guideline has also been introduced to evaluate the basic mechanical properties of the bone components and the tendon graft.
Integrated Study of the Dinitrobenzene Electroreduction Mechanism by Electroanalytical and Computational Methods
Authors: Mendkovich Andrey S. , Syroeshkin Mikhail A. , Mikhalchenko Ludmila V. , Mikhailov Mikhail N. , Rusakov Alexander I. , Gul'tyai Vadim P.
Published: October 2010

Electroreduction of 1,2-, 1,3-, and 1,4-dinitrobenzenes in DMF has been investigated by a set of experimental (cyclic voltammetry, chronoamperometry, and controlled potential electrolysis) and theoretical methods (digital simulation and quantum chemical calculations). The transformation of only one nitro group is observed in the presence of proton donors. The process selectivity is provided by reactions of radical anions' intermediate products. The key reactions here are protonation of radical anions of nitrosonitrobenzenes and N-O bond cleavage in radical anions of N-(nitrophenyl)-hydroxylamines.
‘We are the forgotten ones’: Occupational stress among university secretaries in Botswana
Authors: Plattner Ilse E. , Mberengwa Diana S.
Published: October 2010

Orientation: Secretaries play an essential role in any work organisation, but their contributions and support in the daily management activities are not always recognised.Research purpose: There is little research on occupational stress among secretaries. Therefore, this study aimed to investigate work-related stressors in the secretarial profession and their association with psychosomatic complaints.Motivations for study: Considering the lack of research on secretaries, it was the objective of this study to investigate occupational stressors in the secretarial profession and their association with psycho-physiological wellbeing.Research design, approach and method: Sixty-four secretaries at the University of Botswana participated in the study (response rate: 43.8%). Data were gathered through a self-administered questionnaire. Correlational analyses were performed using Spearman’s rho.Main findings: Seventeen potential stressors were identified, referring to lack of job clarity, performing work outside one’s job description, reduced competencies, supervisors who perform secretarial work, sharing resources such as an office or a telephone, lack of recognition and limited opportunities for promotion. Most stressors correlated significantly with one or more psychosomatic complaints.Practical/managerial implications: Additional research would be necessary to compare various work contexts and organisation-specific work environments and to investigate their relevance to occupational stress and health among secretaries.Contribution/value-add: The results of the study could be of use for human resource managers, as well as for supervisors of secretaries, in order to minimise potential stressors that could negatively affect the health of secretaries.
Exploring trust relationships during times of change
Authors: Von der Ohe Hartmut , Martins Nico
Published: October 2010

Orientation: In the current economic climate and the resulting fast-changing global business and political environment, trust among different role players in organisations has become critical for survival.Research purpose: The objective of this study was to explore the impact of different variables such as demographics on trust relationships in South African organisations.Motivation for the study: Anecdotal evidence and preliminary data collected for a national trust indicator seemed to suggest a shift in trust levels in organisations.Research design: A trust questionnaire was administered to a convenience sample of 307 respondents in all economic sectors. Parametric and nonparametric analyses were used to determine significant differences among economic sectors, job levels and sample periods.Main findings: No significant differences were found for job levels or the different sample periods. However, significant differences were found for the economic sectors and, specifically, between government participants and other sectors for the dimensions of change, team management, organisational trust, information sharing and credibility.Practical implications: In times of change, leadership in organisations need to be aware of the impact on trust levels. It is therefore important that leaders in government focus more on trust-enhancing behaviours needed to repair mistrust in organisations.Contribution: Although the effect of time on trust levels is inconclusive, the clearly differing levels of trust in various economic sectors point to the importance of appropriate and fitting approaches to building trust and not a ‘one-size-fits-all’ attitude.
Tri-Diagonal Preconditioner for Toeplitz Systems from Finance
Authors: Pang Hong-Kui , Zhang Ying-Ying , Jin Xiao-Qing
Published: October 2010

We consider a nonsymmetric Toeplitz system which arises in the discretization of a partial integro-differential equation in option pricing problems. The preconditioned conjugate gradient method with a tri-diagonal preconditioner is used to solve this system. Theoretical analysis shows that under certain conditions the tri-diagonal preconditioner leads to a superlinear convergence rate. Numerical results exemplify our theoretical analysis.
Using multiple scales to estimate the projected frontal surface area of complex three‐dimensional shapes such as flexible freshwater macrophytes at different flow conditions
Authors: Sagnes Pierre
Published: October 2010

For different purposes, the projected frontal surface area (Af) of various organisms is often measured through image analysis. Such Af estimates are particularly used to assess the drag coefficient (Cd) in hydro‐ or aerodynamic studies of organisms. So far, estimates of Af from image analysis were generally biased (as subsequent Cd assessments) for flexible organisms at a given flow, as these estimates were obtained using the same scale for parts of the body being close to or far from the camera. To assess this problem, I used image analyses on 3 flexible freshwater macrophytes, each exposed to 3 different flows. For these, using a single image scale resulted in ~20% errors of Af estimates if compared with a multiple scale (16 subscales, providing the “reference area”) assessment. Using 4 subscales and a human‐controlled plant contour definition for Af estimates was a good trade‐off between accuracy of Af estimates (error < 3% if compared with the reference area) and analysis effort (6 to 10 min for 1 plant in 1 flow condition). In comparison, using an automated definition of the plant contour (through computer software) and a composite scale (i.e., the mean of the 4 previous subscales) provided slightly worse Af estimates (error < 5% if compared with the reference area). Using the automatic procedure reduced the time to estimate Af for 1 plant in 1 flow condition by ~30%. Therefore, future studies requiring accurate Af assessments of flexible, complex, and elongated bodies should use an appropriate number of subscales as reference.
Using laser diffraction data to obtain accurate particle size distributions: the role of particle composition
Authors: Andrews Stephen , Nover Daniel , Schladow S. Geoffrey
Published: October 2010

Suspended particle composition has a large influence on light scattering by small (<20 µm) particles. Inorganic particles and organic phytoplankton cells, both common in natural waters, have very different indices of refraction. This can affect results from laser diffraction particle size analyzers, which measure light scattering and assume an index of refraction to calculate the particle size distribution. Here we examine the effect of the assumed index of refraction on laser diffraction data. A Laser In‐situ Scattering and Transmissometry (LISST) 100X instrument is used to record scattered light distributions from glass microspheres, phytoplankton monocultures, and natural particle samples of mixed composition. The scattering distributions are processed with kernel matrices, derived using Mie theory, assuming either organic or inorganic compositions. Resulting particle size distributions are compared against microscope images. Processing with an assumed inorganic index of refraction was found to produce the most accurate results over the majority of the samples tested. The effect of scattering by particles having diameters outside the instrument inversion range was also assessed. The presence of significant concentrations of particles exceeding the upper limit of the LISST range (>250 µm) produced little effect; however, particles smaller than the lower limit (<1.25 µm) influenced concentrations over the entire LISST size range and produced counterintuitive effects, such as increased concentrations in the largest size bins.
Methods for rearing the invasive zooplankter Bythotrephes in the laboratory
Authors: Kim Natalie , Yan Norman D.
Published: October 2010

The invasive spiny water flea's (Bythotrephes longimanus) current North American distribution encompasses the Laurentian Great Lakes as well as a number of inland lakes, particularly on the Canadian Shield. In the past, poor survival in the laboratory has precluded controlled long‐term studies on Bythotrephes. Here we investigated field collection techniques and choices of culture media, temperature, and diet that led to the successful maintenance of Bythotrephes from birth to reproduction. Gravid parthenogenic females were collected from invaded lakes. Resulting offspring were reared in source lake water filtered through 20 or 80 µm, or a fully defined artificial culture medium, FLAMES. Individuals raised in FLAMES produced significantly larger broods than those in lake water, indicating that it is an appropriate culture medium. We next conducted a 96‐h temperature bioassay on juvenile Bythotrephes. Survival was comparable at 16°C, 20°C, and 24°C but decreased after 48 h at 28°C, and most animals died after 24 h at 32°C. We also reared Bythotrephes at 16°C, 19°C, 22°C, and 25°C. Corresponding intrinsic rates of natural increase (r) for animals maintained to first brood release were 0.02, 0.05, 0.06, and 0.03 d−1, suggesting that Bythotrephes should be reared at ~22°C to benefit from maximum population increases. Feeding trials confirmed that young Bythotrephes prefer small, slow‐moving prey. Finally, we devised a protocol for rearing Bythotrephes that yielded 100% survival to reproduction and r = 0.10 d−1 (for animals maintained to first brood release). Given these results, it is now possible to conduct long‐term laboratory studies on this invader.
A modelling study of photochemical regimes over Europe: robustness and variability
Authors: Beekmann M. , Vautard R.
Published: October 2010

Abstract. The variability of the relative sensitivity of photochemical ozone formation to volatile organic compounds (VOC) and NOx emissions, the chemical regime, over Europe during summers 2001 to 2003 is simulated with a regional scale transport-chemistry model. The robustness and variability of chemical regimes is shown. A VOC sensitive regime over North-Western Europe and a mainly NOx sensitive regime over the Mediterranean basin and Eastern Europe are found, confirming earlier published results. The chemical regime time variability, its robustness with respect to several environmental factors (seasonality, interannual variability) and with respect to model uncertainty are thoroughly analysed. For the regions with well pronounced chemical regimes over North-Western Europe and the Mediterranean, the chemical regime occurrence only slightly depends on the ozone target considered – daily ozone or Ox (= O3 + NO2) maximum or mean, AOT's, SOMO35, .... For these regions, differences between particular years and summer months are weak, day to day variability is significant but does not change the occurrence of one or another chemical regime. On the contrary, over North-Eastern Germany, the chemical regime changes form one day to another and is also dependent on the ozone target chosen. Expected decreases in anthropogenic NOx emissions over Europe since the last and for the next few decades have shifted and will shift chemical regimes to more NOx sensitive. The predictive skill of chemical regime indicator species is made evident at continental scale, extending their spatial range of applicability with respect to earlier studies. Several sensitivity tests were performed in order to account for major sources of model uncertainty. With the exception of regions near ship tracks over the Mediterranean basin, the spatial pattern of chemical regimes appears to be robust with respect to model uncertainty for all cases tested.