bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatially explicit fire-climate history of the boreal forest-tundra (Eastern Canada) over the last 2000 years
Authors: Payette Serge , Filion Louise , Delwaide Ann
Published: November 2007

Across the boreal forest, fire is the main disturbance factor and driver of ecosystem changes. In this study, we reconstructed a long-term, spatially explicit fire history of a forest-tundra region in northeastern Canada. We hypothesized that current occupation of similar topographic and edaphic sites by tundra and forest was the consequence of cumulative regression with time of forest cover due to compounding fire and climate disturbances. All fires were mapped and dated per 100 year intervals over the last 2000 years using several fire dating techniques. Past fire occurrences and post-fire regeneration at the northern forest limit indicate 70% reduction of forest cover since 1800 yr BP and nearly complete cessation of forest regeneration since 900 yr BP. Regression of forest cover was particularly important between 1500s–1700s and possibly since 900 yr BP. Although fire frequency was very low over the last 100 years, each fire event was followed by drastic removal of spruce cover. Contrary to widespread belief of northward boreal forest expansion due to recent warming, lack of post-fire recovery during the last centuries, in comparison with active tree regeneration more than 1000 years ago, indicates that the current climate does not favour such expansion.
Cardiovascular Disease Disparities in Native Hawaiians
Authors: Aluli Noa Emmett , Reyes Phillip W. , Tsark JoAnn ‘Umilani
Published: November 2007

Although Hawaii boasts relatively low rates of death from heart disease and stroke, past data suggest that Native Hawaiians bear a disproportionate burden of mortality from cardiovascular disease (CVD). This study examined 2005–2006 data on CVD mortality and risk factors to see if disparities experienced historically by Native Hawaiians have continued, increased, or been reduced. Existing data were reviewed related to CVD and risk factors for Native Hawaiians in Hawaii and compared with statewide and US rates. These data show that Native Hawaiians are experiencing continuing and perhaps growing disparities in CVD mortality rates and risk factor prevalence. Nevertheless, increased support for enlightened social policy and community‐directed problem solving can help reduce CVD health disparities experienced by Native Hawaiians. Future research should be directed at better delineation of the various components of cardiometabolic risk and culturally sensitive, and educationally appropriate approaches to CVD risk reduction.
Neuronal nitric oxide synthase control mechanisms in the cutaneous vasculature of humans in vivo
Authors: Kellogg Dean L. , Zhao Joan L. , Wu Yubo
Published: November 2007

The physiological roles of constituitively expressed nitric oxide synthase (NOS) isoforms in humans, in vivo, are unknown. Cutaneous vasodilatation during both central nervous system‐mediated, thermoregulatory reflex responses to whole‐body heat stress and during peripheral axon reflex‐mediated, local responses to skin warming in humans depend on nitric oxide (NO) generation by constituitively expressed NOS of uncertain isoform. We hypothesized that neuronal NOS (nNOS, NOS I) effects cutaneous vasodilatation during whole‐body heat stress, but not during local skin warming. We examined the effects of the nNOS inhibitor 7‐nitroindazole (7‐NI) administered by intradermal microdialysis on vasodilatation induced by whole‐body heat stress or local skin warming. Skin blood flow (SkBF) was monitored by laser–Doppler flowmetry (LDF). Blood pressure (MAP) was monitored and cutaneous vascular conductance calculated (CVC = LDF/MAP). In protocol 1, whole‐body heat stress was induced with water‐perfused suits. In protocol 2, local skin warming was induced through local warming units at LDF sites. At the end of each protocol, 56 mm sodium nitroprusside was perfused at microdialysis sites to raise SkBF to maximal levels for data normalization. 7‐NI significantly attenuated CVC increases during whole‐body heat stress (P < 0.05), but had no effect on CVC increases induced by local skin warming (P > 0.05). These diametrically opposite effects of 7‐NI on two NO‐dependent processes verify selective nNOS antagonism, thus proving that the nNOS isoform affects NO increases and hence vasodilatation during centrally mediated, reflex responses to whole‐body heat stress, but not during locally mediated, axon reflex responses to local skin warming. We conclude that the constituitively expressed nNOS isoform has distinct physiological roles in cardiovascular control mechanisms in humans, in vivo.
Assessment of Very High Order of Accuracy in Implicit LES models
Authors: Mosedale Andrew , Drikakis Dimitris
Published: November 2007

This paper looks at the use of high-resolution and very high-order methods for implicit large-eddy simulation (ILES), with the specific example of simulating the multicomponent two-dimensional single-mode Richtmyer–Meshkov instability for which experimental data is available. The two gases are air and SF6, making stringent demands on the models used in the code. The interface between the two gases is initialized with a simple sinusoidal perturbation over a wavelength of 59mm, and a shock of strength Mach 1.3 is passed through this interface. The main comparison is between the second-order monotone upwind-centered scheme for conservation law methods of van Leer (1979, “Towards the Ultimate Conservative Difference Scheme,” J. Comput. Phys. 32, pp. 101–136) and the current state-of-the-art weighted essentially nonoscillatory interpolation, which is presented to ninth order, concentrating on the effect on resolution of the instability on coarse grids. The higher-order methods as expected provide better resolved and more physical features than the second-order methods on the same grid resolution. While it is not possible to make a definitive statement, the simulations have indicated that the extra time required for the higher-order reconstruction is less than the time saved by being able to obtain the same or better accuracy at lower computational cost (fewer grid points). It should also be noted that all simulations give a good representation of the growth rate of the instability, comparing very favorably to the experimental results, and as such far better than the currently existing theoretical models. This serves to further indicate that the ILES approach is capable of providing accurately physical information despite the lack of any formal subgrid model.
Detection of multiple flow regimes in capillary flow at low shear stress
Authors: Shaw Montgomery T.
Published: November 2007

The examination of capillary flow of polymers has resulted in reports of two distinct flow regimes at stresses well below that required for gross melt fracture. The break (kink) between the two regimes has been associated with the onset of sharkskin melt fracture (SSMF), which does not appear to be consistent with the popular hypothesis that SSMF is purely an exit phenomenon. We scrutinized 37 sets of data from 15 laboratories to detect the reported regimes in a systematic and objective fashion using several statistical tests including the Akaike information content method of model discrimination. Many data sets failed to pass one or more of the tests, and several failed all the tests, suggesting the absence of two distinct regimes as opposed to the expected increase in shear-thinning behavior with increasing stress. On the other hand, four out of the 37 sets passed all the tests and 11 out of 37 passed at least 3 of the 4 tests, leaving open the hypothesis of an abrupt change in flow behavior in the capillary itself or in the entrance region. No global correlation of the results with polymer type, capillary geometry, or temperature was found, although with certain resins the abrupt change appeared most prominently with low-aspect-ratio capillaries, suggesting an entrance phenomenon. A method of quantitatively judging the sharpness of the transition from one regime to another was developed. This method, comprising a single nonlinear but explicit generalized Newtonian fluid function with a sharpness parameter, can be easily applied to any data set and is recommended as a method of checking for the presence of a kink.
Short-term glucocorticoid intake combined with intense training on performance and hormonal responses
Authors: Collomp K , Arlettaz A , Portier H , Lecoq A-M , Le Panse B , Rieth N , De Ceaurriz J
Published: November 2007

Objective:

To investigate the effects of short-term prednisolone ingestion combined with intense training on exercise performance, hormonal (adrenocorticotrophic hormone (ACTH), prolactin, luteinising hormone (LH), growth hormone (GH), thyroid-stimulating hormone (TSH), dehydroepiandrosterone (DHEA), testosterone, insulin) and metabolic parameters (blood glucose, lactate, bicarbonate, pH).

Methods:

Eight male recreational athletes completed four cycling trials at 70–75% peak O2consumption until exhaustion just before (1) and after (2) either oral placebo or prednisolone (60 mg/day for 1 week) treatment coupled with standardised physical training (2 hours/day), according to a double-blind and randomised protocol. Blood samples were collected at rest, during exercise and passive recovery for the hormonal and metabolic determinations.

Results:

Time of cycling was not significantly changed after placebo but significantly increased (p<0.05) after prednisolone administration (50.4 (6.2) min for placebo 1, 64.0 (9.1) min for placebo 2, 56.1 (9.1) min for prednisolone 1 and 107.0 (20.7) min for prednisolone 2). There was no significant difference in any measured parameters after the week of training with placebo but a decrease in ACTH, DHEA, PRL, GH, TSH and testosterone was seen with prednisolone treatment during the experiment (p<0.05). No significant change in basal, exercise or recovery LH, insulin, lactate, pH or bicarbonate was found between the two treatment, but blood glucose was significantly higher under prednisolone (p<0.05) at all time points.

Conclusion:

Short-term glucocorticoid administration induced a marked improvement in endurance performance. Further studies are needed to determine whether these results obtained in recreational male athletes maintaining a rigorous training schedule are gender-dependent and applicable to elite athletes.
Narratives in specialist palliative medicine
Authors: Malthouse M
Published: November 2007

Where modern medicine has been criticised for having lost sight of the individual on account of its biomedical focus, the profile of narrative in medicine has gained prominence. Within any medical encounter it is possible to identify the existence of several narratives. The aim of this article is to demonstrate this characteristic within the context of specialist palliative care. The emphasis is to see how an awareness of these narratives might improve upon how we attend to the suffering of dying patients. A narrative approach to this work could also help doctors and other healthcare professionals find meaning and understanding in themselves while working in an environment of death and dying. This can expose many challenging personal dimensions that demand reflection, possibly through narrative. The nature of the narratives identified is such that they can weave together and interlink into a greater whole to achieve a much wider set of meanings and shared understandings. However, they can exist in a fragmented state, in which ambiguity, uncertainty and incoherence are sustained. The effect of this should be to encourage us to engage in a more active process of finding meaning, and certainly to recognise that there could be more than one reading or interpretation.
The body as metaphor: digestive bodies and political surgery in Shakespeare’sMacbeth
Authors: Spicci M
Published: November 2007

The article aims to reconstruct the perspective of bodily pathology underpinning Shakespeare’sMacbeth. In the play, Scotland’s body politic is frequently depicted as a macro-system suffering from a complexional imbalance of digestive origins. More specifically, Scotland comes over as a huge stomach strangled by a carcinogenic foreign body in need of being “raze[d] out”. Since traditional purgative drugs such as “rhubarb” and “cynne” turn out to be totally inefficient to cure the body of Scotland, the resolution to adopt a drastic medical measure becomes more than urgent. The conclusion of the play coincides with the most terrible form of political surgery: Shakespeare’s reiterated use of verbs such as “pluck” and “purge”, commonly used in Renaissance herbals and handbooks, suggests that Macbeth’s physical body is suffering from a kind of “blockage”, for which herbal treatments are no longer sufficient. Nothing less than a surgical operation is needed to “purge” the corrupt entrails of the State dominated by Macbeth’s tyranny.
Short-term growth (RNA/DNA ratio) of yellow perch (Perca flavescens) in relation to environmental influences and spatio-temporal variation in a shallow fluvial lake
Authors: Glémet Hélène , Rodríguez Marco A
Published: November 2007

Shallow fluvial lakes are heterogeneous ecosystems in which marked spatio-temporal variation renders difficult the analysis of key ecological processes, such as growth. In this study, we used generalized additive modelling of the RNA/DNA ratio, an index of short-term growth, to investigate the influence of environmental variables and spatio-temporal variation on growth of yellow perch (Perca flavescens) in Lake St. Pierre, Quebec, Canada. Temperature and water level had seemingly stronger effects on short-term growth than seasonal change or spatial variation between and along the lakeshores. Consistent with previous studies, the maximum RNA/DNA ratio was found at 20.5 °C, suggesting that our approach provides a useful tool for estimating thermal optima for growth in the field. The RNA/DNA ratio showed a positive relationship with water level, as predicted by the flood pulse concept, a finding with implications for ecosystem productivity in fluvial lakes. The RNA/DNA ratio was more variable along the north than the south shore, possibly reflecting exposure to more differentiated water masses. The negative influence of both high temperatures and low water levels on growth points to potential impacts of climatic change on fish production in shallow fluvial lakes.
Comparative distribution and invasion risk of snakehead (Channidae) and Asian carp (Cyprinidae) species in North America
Authors: Herborg Leif-Matthias , Mandrak Nicholas E , Cudmore Becky C , MacIsaac Hugh J
Published: November 2007

As nonindigenous species are a major threat to global biodiversity, cost-effective management requires identification of areas at high risk of establishment. Here we predict suitable environments of 14 high-profile species of nonindigenous snakehead (Channidae) and Asian carp (Cyprinidae) species in North America based upon ecological niche modelling and compare the driving environmental variables for the two fish groups. Snakeheads distributions were correlated with thermal factors, whereas those of Asian carps were related mainly to precipitation. Predicted suitable ranges for these nonindigenous species can be divided into three main areas: Mexico and the southern United States (five species); Mexico and the United States up to ~35 °N (three species); and most of Mexico, continuous United States, and southern Canada (six species). For the province of Ontario, we combined the number and location of aquarium stores and live fish markets with predicted areas of suitable environments to identify areas at risk of introduction and establishment. We identified several watersheds draining into northwestern Lake Ontario as having the highest risk, highlighting the increased predictive value of this approach.
A fishery-independent assessment of an overfished rockfish stock, cowcod (Sebastes levis), using direct observations from an occupied submersible
Authors: Yoklavich Mary M , Love Milton S , Forney Karin A
Published: November 2007

A meaningful assessment of cowcod (Sebastes levis) has been conducted using visual, nonextractive, habitat-specific methods. Following the precipitous decline of rockfish (Sebastes spp.) stocks along the Pacific coast, it was evident that more effective methods were needed to assess several species in untrawlable habitats. Cowcod were surveyed within large Cowcod Conservation Areas (CCAs) off southern California using direct observations from the research submersible Delta over eight major offshore rocky banks in depths of 74 to 322 m. Maps of seafloor substratum and bathymetry were used to identify and quantify these areas. A line-transect analysis of fish counts, perpendicular distances of fish from the track line, lengths of survey tracks, and area of each rocky bank was used to estimate abundance. Biomass, calculated from abundance, fish length, and a weight–length relationship, varied with mean size of cowcod on these banks. These fishery-independent results have contributed to the recent assessment of cowcod by the Pacific Fishery Management Council. A time series of results from visual surveys is now necessary to evaluate a trend in cowcod biomass with respect to increased time of protection within the CCAs.
Chromosomal rearrangements in wheat: their types and distribution
Authors: Badaeva E. D. , Dedkova O. S. , Gay G. , Pukhalskyi V. A. , Zelenin A. V. , Bernard S. , Bernard M.
Published: November 2007

Four hundred and sixty polyploid wheat accessions and 39 triticale forms from 37 countries of Europe, Asia, and USA were scored by C-banding for the presence of translocations. Chromosomal rearrangements were detected in 70 of 208 accessions of tetraploid wheat, 69 of 252 accessions of hexaploid wheat, and 3 of 39 triticale forms. Altogether, 58 types of major chromosomal rearrangements were identified in the studied material; they are discussed relative to 11 additional translocation types described by other authors. Six chromosome modifications of unknown origin were also observed. Among all chromosomal aberrations identified in wheat, single translocations were the most frequent type (39), followed by multiple rearrangements (9 types), pericentric inversions (9 types), and paracentric inversions (3 types). According to C-banding analyses, the breakpoints were located at or near the centromere in 60 rearranged chromosomes, while in 52 cases they were in interstitial chromosome regions. In the latter case, translocation breakpoints were often located at the border of C-bands and the euchromatin region or between two adjacent C-bands; some of these regions seem to be translocation “hotspots”. Our results and data published by other authors indicate that the B-genome chromosomes are involved in translocations most frequently, followed by the A- and D-genome chromosomes; individual chromosomes also differ in the frequencies of translocations. Most translocations were detected in 1 or 2 accessions, and only 11 variants showed relatively high frequencies or were detected in wheat varieties of different origins or from different species. High frequencies of some translocations with a very restricted distribution could be due to a “bottleneck effect”. Other types seem to occur independently and their broad distribution can result from selective advantages of rearranged genotypes in diverse environmental conditions. We found significant geographic variation in the spectra and frequencies of translocation in wheat: the highest proportions of rearranged genotypes were found in Central Asia, the Middle East, Northern Africa, and France. A low proportion of aberrant genotypes was characteristic of tetraploid wheat from Transcaucasia and hexaploid wheat from Middle Asia and Eastern Europe.
Development of genomic microsatellite markers in Coffea canephora and their transferability to other coffee species
Authors: Poncet Valérie , Dufour Magali , Hamon Perla , Hamon Serge , de Kochko Alexandre , Leroy Thierry
Published: November 2007

Of the 103 accepted Coffea species, 70% are threatened with extinction but only a few of them have been studied. A set of 40 polymorphic microsatellite markers was developed using a GA/GT-enriched Coffea canephora genomic library. Amplification of these markers was tested in accessions of C. heterocalyx (a Critically Endangered species) and C. pseudozanguebariae (a Vulnerable species) belonging to different African geographical clades. All microsatellites were polymorphic in C. canephora, with a mean allele number per polymorphic locus of more than 3 (at least 9 genotypes were tested). Observed and expected heterozygosities calculated for C. canephora and C. pseudozanguebariae varied from 0.10 to 0.91 and from 0.20 to 0.77, respectively. In total, 38 primer pairs (95%) were amplified in C. heterocalyx and C. pseudozanguebariae, indicating their high level of transferability across the genus Coffea. This large marker set will be useful for more extensive genetic studies of threatened Coffea species.
Differences in efficiency between trained and recreational cyclists
Authors: Hopker James G. , Coleman Damian A. , Wiles Jonathan D.
Published: November 2007

Controversy still exists in the literature as to whether cycling experience affects gross mechanical efficiency (GME). The aim of this study was to identify differences in efficiency between trained and untrained cyclists. Thirty-two participants, 16 trained (mean ± SD: age, 33 ± 4 y; height, 1.76 ± 0.05 m; mass 75 ± 10 kg; Wmax, 421 ± 38 W; maximal oxygen uptake, 62.6 ± 7.30 mL·kg–1·min–1) and 16 untrained (22 ± 3 y, 175 ± 0.06 m, 76 ± 10 kg, 292 ± 34 W, 42.6 ± 7.80 mL·kg–1·min–1), performed two tests of cycling efficiency. One was at the relative workloads of 50% and 60% Wmax and the other was at a fixed workload of 150 W using an electrically braked cycle ergometer. Cadence was maintained at the cyclist’s preferred rate throughout. All workloads lasted 10 min with data sampling in the final 3 min. GME was calculated from the gas data. GME was found to be significantly higher in the trained cyclists across all workloads (+1.4%; p = 0.03). At workloads of 60% Wmax GME was significantly lower than work at 150 W (–0.8%; p = 0.04), but not significantly different from 50%Wmax. These results show that differences do exist between trained and untrained cyclists, illustrating that training experience is a factor that warrants further investigation.
Exercise, aging, and cancer
Authors: Courneya Kerry S. , Karvinen Kristina H.
Published: November 2007

Cancer is a common disease that affects over 150 000 Canadians every year. About 78% of all cancers are diagnosed in adults aged 60 years and older. Improved survival rates for cancer survivors have brought lifestyle and quality of life issues to the forefront. In other chronic disease populations, exercise is considered a foundational health behavior; however, the benefits of exercise in cancer survivors are only beginning to be described. Moreover, what little is known about exercise in cancer survivors has been derived largely from research on middle-aged survivors. In the present article, we review the literature on exercise, aging, and cancer. Our review shows that very few studies have examined exercise in older cancer survivors or have approached the topic from an aging perspective. The limited research that is available suggests that, compared with middle-aged cancer survivors, older cancer survivors: (i) derive similar benefits from exercise, (ii) have lower exercise participation rates, (iii) have more difficulty adhering to an exercise program, and (iv) have different determinants of exercise motivation and behavior. We end by offering some future research directions that may help generate important new exercise knowledge in this underserved cancer survivor population.
Limitations of Canada’s physical activity data: implications for monitoring trendsThis article is part of a supplement entitled Advancing physical activity measurement and guidelines in Canada: a scientific review and evidence-based foundation for the future of Canadian physical activity guidelines co-published by Applied Physiology, Nutrition, and Metabolism and the Canadian Journal of Public Health. It may be cited as Appl. Physiol. Nutr. Metab. 32(Suppl. 2E) or as Can. J. Public Health 98(Suppl. 2).
Authors: Katzmarzyk Peter T. , Tremblay Mark S.
Published: November 2007

The current low level of physical activity among Canadians is a dominant public health concern. Accordingly, a clear understanding of physical activity patterns and trends is of paramount importance. Irregularities in monitoring, analysis, and reporting procedures create potential confusion among researchers, policy-makers, and the public alike. The purpose of this paper is to consolidate reported findings and provide a critical assessment of the physical activity surveillance procedures, analytical practices, and reporting protocols currently employed in Canada to provide insights for accurate and consistent interpretation of data, as well as recommendations for future surveillance efforts.
Evidence-informed physical activity guidelines for Canadian adultsThis article is part of a supplement entitled Advancing physical activity measurement and guidelines in Canada: a scientific review and evidence-based foundation for the future of Canadian physical activity guidelines co-published by Applied Physiology, Nutrition, and Metabolism and the Canadian Journal of Public Health. It may be cited as Appl. Physiol. Nutr. Metab. 32(Suppl. 2E) or as Can. J. Public Health 98(Suppl. 2).
Authors: Warburton Darren E.R. , Katzmarzyk Peter T. , Rhodes Ryan E. , Shephard Roy J.
Published: November 2007

This review of the literature provides an update on the scientific biological and psychosocial bases for Canada’s physical activity guide for healthy active living, with particular reference to the effect of physical activity on the health of adults aged 20–55 years. Existing physical activity guidelines for adults from around the world are summarized briefly and compared with the Canadian guidelines. The descriptive epidemiology of physical activity and inactivity in Canada is presented, and the strength of the relationship between physical activity and specific health outcomes is evaluated, with particular emphasis on minimal and optimal physical activity requirements. Finally, areas requiring further investigation are highlighted. Summarizing the findings, Canadian and most international physical activity guidelines advocate moderate-intensity physical activity on most days of the week. Physical activity appears to reduce the risk for over 25 chronic conditions, in particular coronary heart disease, stroke, hypertension, breast cancer, colon cancer, type 2 diabetes, and osteoporosis. Current literature suggests that if the entire Canadian population followed current physical activity guidelines, approximately one third of deaths related to coronary heart disease, one quarter of deaths related to stroke and osteoporosis, 20% of deaths related to colon cancer, hypertension, and type 2 diabetes, and 14% of deaths related to breast cancer could be prevented. It also appears that the prevention of weight gain and the maintenance of weight loss require greater physical activity levels than current recommendations.
A mild and efficient synthesis of chloroesters by the cleavage of cyclic and acyclic ethers using Bi(NO3)3·5H2O as a catalyst under solvent-free conditions
Authors: Suresh V , Suryakiran N , Venkateswarlu Y
Published: November 2007

A facile, efficient synthesis of chloroesters is described. The reaction of cyclic and acyclic ethers with acid chlorides in the presence of catalytic amounts of Bi(NO3)3·5H2O under solvent-free conditions yielded the corresponding chloroesters. Also, the catalyst can be recovered conveniently and reused efficiently for at least six times.Key words: Bismuth(III) nitrate pentahydrate, cyclic and acyclic ethers, chloroesters.
INVARIANT MANIFOLD WITH COMPLETE FOLIATIONS AND CHAOTIFICATION ANALYSIS FOR A KIND OF PDES WITH BOUNDARY COUPLING
Authors: XIE LINGLI , TEO KOK-LAY , ZHAO YI
Published: November 2007

In this paper, we are concerned with the existence of invariant manifolds and complete foliations for a class of PDEs with boundary coupling. Some new form of gap relative coupling and inequality conditions are obtained. Further, we prove the topological equivalence of the flows in the respective attractors between the system and its spatial discretization system (an ODE system). Finally, the chaotification of the system is discussed through an example and simulation is generated to illustrate the theoretical results.
ON THE NUMBER OF ZEROS OF THE ABELIAN INTEGRALS FOR A CLASS OF PERTURBED LIÉNARD SYSTEMS
Authors: ZHANG TONGHUA , TIAN YU-CHU , TADÉ MOSES O.
Published: November 2007

Addressing the weakened Hilbert's 16th problem or the Hilbert–Arnold problem, this paper gives an upper bound B(n) ≤ 7n + 5 for the number of zeros of the Abelian integrals for a class of Liénard systems. We proved the main result using the Picard–Fuchs equations and the algebraic structure of the integrals.
Oblivious routing on node-capacitated and directed graphs
Authors: Hajiaghayi Mohammad Taghi , Kleinberg Robert D. , Räcke Harald , Leighton Tom
Published: November 2007

Oblivious routing algorithms for general undirected networks were introduced by Räcke [2002], and this work has led to many subsequent improvements and applications. Comparatively little is known about oblivious routing in general
directed
networks, or even in undirected networks with node capacities.

We present the first nontrivial upper bounds for both these cases, providing algorithms for
k
-commodity oblivious routing problems with competitive ratio
O
(√
k
log(
n
)) for undirected node-capacitated graphs and
O
(√
k
n
1/4
log(
n
)) for directed graphs. In the special case that all commodities have a common source or sink, our upper bound becomes
O
(√
n
log(
n
)) in both cases, matching the lower bound up to a factor of log(
n
). The lower bound (which first appeared in Azar et al. [2003]) is obtained on a graph with very high degree. We show that, in fact, the degree of a graph is a crucial parameter for node-capacitated oblivious routing in undirected graphs, by providing an
O
(Δ polylog(
n
))-competitive oblivious routing scheme for graphs of degree Δ. For the directed case, however, we show that the lower bound of Ω(√
n
) still holds in low-degree graphs.

Finally, we settle an open question about routing problems in which all commodities share a common source or sink. We show that even in this simplified scenario there are networks in which no oblivious routing algorithm can achieve a competitive ratio better than Ω(log
n
).
Towards a query optimizer for text-centric tasks
Authors: Ipeirotis Panagiotis G. , Agichtein Eugene , Jain Pranay , Gravano Luis
Published: November 2007

Text is ubiquitous and, not surprisingly, many important applications rely on textual data for a variety of tasks. As a notable example, information extraction applications derive structured relations from unstructured text; as another example, focused crawlers explore the Web to locate pages about specific topics. Execution plans for text-centric tasks follow two general paradigms for processing a text database: either we can scan, or “crawl,” the text database or, alternatively, we can exploit search engine indexes and retrieve the documents of interest via carefully crafted queries constructed in task-specific ways. The choice between crawl- and query-based execution plans can have a substantial impact on both execution time and output “completeness” (e.g., in terms of recall). Nevertheless, this choice is typically ad hoc and based on heuristics or plain intuition. In this article, we present fundamental building blocks to make the choice of execution plans for text-centric tasks in an informed, cost-based way. Towards this goal, we show how to analyze query- and crawl-based plans in terms of both execution time and output completeness. We adapt results from random-graph theory and statistics to develop a rigorous cost model for the execution plans. Our cost model reflects the fact that the performance of the plans depends on fundamental task-specific properties of the underlying text databases. We identify these properties and present efficient techniques for estimating the associated parameters of the cost model. We also present two optimization approaches for text-centric tasks that rely on the cost-model parameters and select efficient execution plans. Overall, our optimization approaches help build efficient execution plans for a task, resulting in significant efficiency and output completeness benefits. We complement our results with a large-scale experimental evaluation for three important text-centric tasks and over multiple real-life data sets.
Exporting and interactively querying Web service-accessed sources
Authors: Petropoulos Michalis , Deutsch Alin , Papakonstantinou Yannis , Katsis Yannis
Published: November 2007

The CLIDE System assists the owners of sources that participate in Web service-based data publishing systems to publish a restricted set of parameterized queries over the schema of their sources and package them as WSDL services. The sources may be relational databases, which naturally have a schema, or ad hoc information/application systems whereas the owner publishes a virtual schema. CLIDE allows information clients to pose queries over the published schema and utilizes prior work on answering queries using views to answer queries that can be processed by combining and processing the results of one or more Web service calls. These queries are called
feasible
. Contrary to prior work, where infeasible queries are rejected without an explanatory feedback, leading the user into a frustrating trial-and-error cycle, CLIDE features a query formulation interface, which extends the QBE-like query builder of Microsoft's SQL Server with a color scheme that guides the user toward formulating feasible queries. CLIDE guarantees that the suggested query edit actions are complete (i.e., each feasible query can be built by following only suggestions), rapidly convergent (the suggestions are tuned to lead to the closest feasible completions of the query), and suitably summarized (at each interaction step, only a minimal number of actions needed to preserve completeness are suggested). We present the algorithms, implementation, and performance evaluation showing that CLIDE is a viable on-line tool.
Are your citations clean?
Authors: Lee Dongwon , Kang Jaewoo , Mitra Prasenjit , Giles C. Lee , On Byung-Won
Published: November 2007

If they are, only one can refer to a distinct document; if not, many can refer to the same document.
Moving beyond user participation to achieve successful IS design
Authors: Wagner Erica L. , Piccoli Gabriele
Published: November 2007

A call for user engagement cannot be scheduled at a specific point in the software development process. Valuable user input comes in waves throughout the project and developers would do best to listen and learn.
Multichannel thin-film electrode for intramuscular electromyographic recordings
Authors: Farina Dario , Yoshida Ken , Stieglitz Thomas , Koch Klaus Peter
Published: November 2007

It is currently not possible to record electromyographic (EMG) signals from many locations concurrently inside the muscle in a single wire electrode system. We developed a thin-film wire electrode system for multichannel intramuscular EMG recordings. The system was fabricated using a micromachining process, with a silicon wafer as production platform for polyimide-based electrodes. In the current prototype, the flexible polymer structure is 220 μm wide, 10 μm thick, and 1.5 cm long, and it has eight circular platinum-platinum chloride recording sites of 40-μm diameter distributed along the front and back surfaces with 1,500-μm intersite spacing. The system prototype was tested in six experiments where the electrode was implanted into the medial head of the gastrocnemius muscle of rabbits, perpendicular to the pennation angle of the muscle fibers. Asynchronous motor unit activity was induced by eliciting the withdrawal reflex or sequential crushes of the sciatic nerve using a pair of forceps. Sixty-seven motor units were identified from these recordings. In the bandwidth 200 Hz to 5 kHz, the peak-to-peak amplitude of the action potentials of the detected motor units was 75 ± 12 μV and the root mean square of the noise was 1.6 ± 0.4 μV. The noise level and amplitude of the action potentials were similar for measures separated by up to 40 min. The experimental tests demonstrated that thin film is a promising technology for a new type of flexible-wire intramuscular EMG recording system with multiple detection sites.
Heritability of lumbar flexibility and the role of disc degeneration and body weight
Authors: Battié Michele C. , Levalahti Esko , Videman Tapio , Burton Kim , Kaprio Jaakko
Published: November 2007

Spinal range of motion is evaluated in assessing patients with back problems and monitoring outcomes, as well as in general fitness assessments. Yet, determinants of the substantial interindividual variation in spinal range of motion are not well understood. Substantial genetic effects on global measures of range of motion and hypermobility have been suggested from earlier studies, but genetic influences specifically on spinal range of motion have not been previously studied. The objectives of the present study were to investigate the relative role of genetic and environmental influences on lumbar range of motion in adult men and the pathways through which genes may influence range of motion. Thus we conducted a classic twin study of 300 monozygotic and dizygotic male twin pairs with consideration of covariates, using standard statistical methods. All subjects underwent a clinical examination, including general anthropometrics, lumbar range of motion, and lumbar MRI to assess disc degeneration, as well as an extensive interview on environmental and behavioral exposures and back pain history. We found the proportion of variance in lumbar range of motion attributable to genetic influences (heritability estimate) to be 47%. The extent of lumbar range of motion in flexion was predominantly determined by genetic influences (64%), while extension was influenced to a somewhat greater degree by environmental and behavioral factors. Statistically significant age-adjusted genetic correlations were found between lumbar extension and disc degeneration variables ( ra= −0.38 to −0.43) and between flexion and body weight ( ra= −0.33), suggesting two pathways through which genes influence lumbar range of motion.
Biomechanics of overground vs. treadmill walking in healthy individuals
Authors: Lee Song Joo , Hidler Joseph
Published: November 2007

The goal of this study was to compare treadmill walking with overground walking in healthy subjects with no known gait disorders. Nineteen subjects were tested, where each subject walked on a split-belt instrumented treadmill as well as over a smooth, flat surface. Comparisons between walking conditions were made for temporal gait parameters such as step length and cadence, leg kinematics, joint moments and powers, and muscle activity. Overall, very few differences were found in temporal gait parameters or leg kinematics between treadmill and overground walking. Conversely, sagittal plane joint moments were found to be quite different, where during treadmill walking trials, subjects demonstrated less dorsiflexor moments, less knee extensor moments, and greater hip extensor moments. Joint powers in the sagittal plane were found to be similar at the ankle but quite different at the knee and hip joints. Differences in muscle activity were observed between the two walking modalities, particularly in the tibialis anterior throughout stance, and in the hamstrings, vastus medialis and adductor longus during swing. While differences were observed in muscle activation patterns, joint moments and joint powers between the two walking modalities, the overall patterns in these behaviors were quite similar. From a therapeutic perspective, this suggests that training individuals with neurological injuries on a treadmill appears to be justified.
Chronic Kidney Disease Is Associated with Angiographic Coronary Artery Disease
Authors: Chonchol Michel , Whittle Jeff , Desbien Angela , Orner Michelle B. , Petersen Laura A. , Kressin Nancy R.
Published: November 2007

Background/Aims: Patients with chronic kidney disease (CKD) have a dramatically increased risk for cardiovascular mortality. Few prior studies have examined the independent association of CKD with coronary anatomy. Methods: We evaluated the relationship between CKD and severe coronary artery disease (CAD) in 261 male veterans with nuclear perfusion imaging tests suggesting coronary ischemia. We used chart review and patient and provider interviews to collect demographics, clinical characteristics, and coronary anatomy results. We defined CKD as an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2, based on the creatinine obtained prior to angiography. We defined significant coronary obstruction as at least one 70% or greater stenosis. We used logistic regression to determine whether CKD was independently associated with significant coronary obstruction. Results: The likelihood of CAD increased monotonically with decreasing eGFR, from 51% among patients with eGFR ≧90 ml/min/1.73 m2 to 84% in those with eGFR <30 ml/min/1.73 m2 (p = 0.0046). Patients with CKD were more likely than those without CKD to have at least one significant coronary obstruction (75.9 vs. 60.7%, p = 0.016). Patients with CKD also had more significant CAD, that is, were more likely to have three-vessel and/or left main disease than those without CKD (34.9 vs. 16.9%, p = 0.0035). In logistic regression analysis, controlling for demographics and comorbidity, CKD continued to be independently associated with the presence of significant CAD (p = 0.0071). Conclusion: CKD patients have a high prevalence of obstructive coronary disease, which may contribute to their high cardiovascular mortality.
Selective Expansion of Influenza A Virus–Specific T Cells in Symptomatic Human Carotid Artery Atherosclerotic Plaques
Authors: Keller Tymen T. , van der Meer Jelger J. , Teeling Peter , van der Sluijs Koen , Idu Mirza M. , Rimmelzwaan Guus F. , Levi Marcel , van der Wal Allard C. , de Boer Onno J.
Published: November 2007

Background and Purpose—

Evidence is accumulating that infection with influenza A virus contributes to atherothrombotic disease. Vaccination against influenza decreases the risk of atherosclerotic syndromes, indicating that inflammatory mechanisms may be involved. We tested the hypothesis that influenza A virus–specific T cells contribute to atherosclerotic plaque inflammation, which mediates the onset of plaque rupture.

Methods—

T-cell cultures were generated from atherosclerotic segments and peripheral blood of 30 patients with symptomatic carotid artery disease. The response of plaque and peripheral blood T cells to influenza A virus was analyzed and expressed as a stimulation index (SI). Selective outgrowth of intraplaque influenza A–specific T cells was calculated by the ratio of plaque T cell SI and peripheral blood T cell SI for each patient. Accordingly, the patients were categorized as high- (SI ratio ≥5), intermediate- (5 <SI ratio ≤2), and non- (SI ratio <2) responders. The presence of influenza A virus in the vessel fragments was evaluated by reverse transcription–polymerase chain reaction.

Results—

High proliferative responses of plaque-derived T cells to influenza A virus were frequently observed. Among the 30 patients, 5 were categorized as high responders, 10 were intermediate responders, and 15 were nonresponders. Live influenza A virus could not be detected in the atherosclerotic plaques by polymerase chain reaction.

Conclusions—

Selective outgrowth of influenza A virus–specific T cells occurs within the microenvironment of human atherosclerotic plaques. Influenza virus–derived antigens or alternatively, mimicry antigens, appear to be potential candidates for triggering or sustaining plaque inflammation, which eventually leads to symptomatic plaque complications.
The 2007 Feinberg Lecture
Authors: Donnan Geoffrey A.
Published: November 2007

Background and Purpose—

There have now been numerous phase III trials of neuroprotection that have failed to live up to the expectations created by preclinical testing in animal models, the most recent of which was the second pivotal trial of the spin trap agent NXY-059. We have reached a stage at which research in this area should stop altogether or radical new approaches adopted. The purpose of this article is to review how we reached this stage and make recommendations for a new approach to neuroprotection research.

Methods—

The background to neuroprotection research is reviewed and its problems are highlighted based on the research of others and of our own research group. From this, a series of questions are posed that require answers if the field is to progress. A road map for future research is then proposed.

Results—

The road map involves the following steps for putative neuroprotectants: (1) better proof of efficacy in animal models; (2) in vivo evidence of efficacy in human tissue using cell cultures or brain slices; (3) in vivo studies of their distribution in the normal and ischemic human brain, particularly focusing on the ischemic penumbra; (4) demonstration of efficacy in novel human models of cerebral ischemia; and (5) phase II and III clinical trails with penumbral selection using imaging techniques.

Conclusions—

The accumulated evidence suggests that neuroprotection failure in clinical trial is due to identifiable preclinical and clinical factors. Neuroprotection research should be pursued but with a very different and more rigorous approach.
Kidney Function Is Related to Cerebral Small Vessel Disease
Authors: Ikram M. Arfan , Vernooij Meike W. , Hofman Albert , Niessen Wiro J. , van der Lugt Aad , Breteler Monique M.B.
Published: November 2007

Background and Purpose—

Poor kidney function, as measured by glomerular filtration rate (GFR), is closely associated with presence of glomerular small vessel disease. Given the hemodynamic similarities between the vascular beds of the kidney and the brain, we hypothesized an association between kidney function and markers of cerebral small vessel disease on MRI. We investigated this association in a population-based study of elderly persons.

Methods—

We measured GFR using the Cockcroft-Gault equation in 484 participants (60 to 90 years of age) from the Rotterdam Scan Study. Using automated MRI-analysis we measured global as well as lobar and deep volumes of gray matter and white matter, and volume of WML. Lacunar infarcts were rated visually. Volumes of deep white matter and WML and presence of lacunar infarcts reflected cerebral small vessel disease. We used linear and logistic regression models to investigate the association between GFR and brain imaging parameters. Analyses were adjusted for age, sex, and additionally for cardiovascular risk factors.

Results—

Persons with lower GFR had less deep white matter volume (difference in standardized volume per SD decrease in GFR: −0.15 [95% CI −0.26 to −0.04]), more WML (difference per SD decrease in GFR: 0.14 [95% CI 0.03 to 0.25]), and more often lacunar infarcts, although the latter was not significant. GFR was not associated with gray matter volume or lobar white matter volume. Additional adjustment for cardiovascular risk factors yielded similar results.

Conclusions—

Impaired kidney function is associated with markers of cerebral small vessel disease as assessed on MRI.