bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photosynthesis and Optimal Light Microhabitats for a Rare Cactus, Mammillaria gaumeri, in Two Tropical Ecosystems
Authors: Cervera J. Carlos , Andrade José Luis , Graham Eric A. , Durán Rafael , Jackson Paula C. , Simá J. Luis 
Published: May 2007

ABSTRACT Mammillaria gaumeri, an endemic cactus from Yucatan, is threatened due to human‐mediated habitat fragmentation but knowledge regarding factors that would inform management plans is limited, including information on optimal microhabitats and growth. We studied seasonal patterns of microclimate, net CO2 uptake and growth of adult individuals during the dry, rainy and northwind (late fall to winter) seasons in separate populations located in a coastal dune and in a dry forest. To provide an assay of primary productivity, we measured the production of new axillary buds (areoles) from the apex. We found that patterns of net CO2 uptake in the three seasons were consistent with obligate crassulacean acid metabolism. The reduction in soil water potential and the increase in water vapor pressure deficit led to a reduction in 24‐h net CO2 uptake from 18.0 to 1.3 mmol CO2/m2, after 30 d of drought. Dry‐weight gain was maximal during the rainy season and there was no growth during the dry season, thus seasonal patterns of net CO2 uptake and growth for M. gaumeri reflected soil and atmospheric water contents. Annual dry‐weight gain increased linearly with plant size and with total daily photosynthetic photon flux density (PPFD) up to 80 percent of ambient. Maximal growth was in exposed microhabitats receiving 60–80 percent of total ambient PPFD. We hypothesize that low‐magnitude disturbances, resulting in more exposed microhabitats, might be beneficial for growth and conservation of adult individuals of this rare species.
Pharmaceuticals in On‐Site Sewage Effluent and Ground Water, Western Montana
Authors: Godfrey Emily , Woessner William W. , Benotti Mark J. 
Published: May 2007

AbstractHuman use of pharmaceuticals results in the excretion and disposal of compounds that become part of municipal and domestic waste streams. On‐site waste water disposal and leaking city sewer systems can provide avenues for the migration of effluent to the underlying aquifers. This research assessed the occurrence and persistence of 22 target pharmaceuticals in septic tank effluent and two shallow, coarse‐grained aquifers in western Montana. Twelve compounds (acetaminophen, caffeine, codeine, carbamazepine, cotinine, erythromycin‐18, nicotine, paraxanthine, ranitidine, sulfamethoxazole, trimethoprim, and warfarin) were detected in a high school septic tank effluent. Three of the 12 compounds, carbamazepine, sulfamethoxazole, and nicotine, were detected in the underlying sand and gravel aquifer after effluent percolation through a 2.0‐m thick sand vadose zone. Sampling of a second sand, gravel, and cobble dominated unconfined aquifer, partially overlain by septic systems and a city sewer system, revealed the presence of caffeine, carbamazepine, cotinine, nicotine, and trimethoprim. The presence of carbamazepine and sulfamethoxazole in these aquifers appears to correlate with local usage based on a reported monthly prescription volume. This work highlights the need for expanding geochemical investigations of sewage waste impacted ground water systems to include sampling for selected pharmaceuticals.
Update on the Use of the RORA Program for Recharge Estimation
Authors: Rutledge Albert T. 
Published: May 2007

AbstractAn update on the use of the RORA program is provided to supplement information given in the initial description of the program in Ground Water in 1994. The method estimates ground water recharge on the basis of streamflow records. Important considerations in the use of the automated approach are described that should improve the reliability of recharge estimates and avoid misapplication of the technique. Topics include the recession index, errors caused by direct surface runoff, the time scale for reporting results, comparisons with results of manual calculations, and errors caused by gradual recharge and discharge. The use of ground water levels for independent assessment of results from RORA is also described. RORA results are compared and contrasted with results from other base flow separation techniques.
Are Models Too Simple? Arguments for Increased Parameterization
Authors: Hunt Randall J. , Doherty John , Tonkin Matthew J. 
Published: May 2007

AbstractThe idea that models should be as simple as possible is often accepted without question. However, too much simplification and parsimony may degrade a model’s utility. Models are often constructed to make predictions; yet, they are commonly parameterized with a focus on calibration, regardless of whether (1) the calibration data can constrain simulated predictions or (2) the number and type of calibration parameters are commensurate with the hydraulic property details on which key predictions may depend. Parameterization estimated through the calibration process is commonly limited by the necessity that the number of calibration parameters be smaller than the number of observations. This limitation largely stems from historical restrictions in calibration and computing capability; we argue here that better methods and computing capabilities are now available and should become more widely used. To make this case, two approaches to model calibration are contrasted: (1) a traditional approach based on a small number of homogeneous parameter zones defined by the modeler a priori and (2) regularized inversion, which includes many more parameters than the traditional approach. We discuss some advantages of regularized inversion, focusing on the increased insight that can be gained from calibration data. We present these issues using reasoning that we believe has a common sense appeal to modelers; knowledge of mathematics is not required to follow our arguments. We present equations in an Appendix, however, to illustrate the fundamental differences between traditional model calibration and a regularized inversion approach.
The Economics of Rising Fuel Costs and European Fisheries Les pêcheries européennes confrontées à la croissance du coût des carburants Die ökonomischen Aspekte steigender Mineralölkosten und europäischer Fischerei
Authors: Arnason Ragnar 
Published: May 2007

summaryThe Economics of European FisheriesThe huge increase in fuel prices — about doubling since 2004 — represents a major economic shock to European fishing fleets. Before this latest price hike, fuel accounted for 15 per cent of the operating costs of most fleet segments. Thus, in spite of various fuel saving measures, this fuel price increase has probably reduced the profitability of European fishing fleets by well over 5 per cent of revenues on average. What is perhaps less obvious is that the fuel price increase also serves to bring the industry more into line with the biological productivity of the fish stocks. Many European fisheries today are characterized by excessive fishing fleets and severely overexploited fish stocks. It is shown in this article that lower profitability in fishing serves to reduce this excessive fishing pressure leading to some fish stock recovery and the possibility of higher sustainable catches. Thus, as painful as it is to the fishing industry, this fuel price increase may actually contribute to a healthier fishery in the longer run, and by increasing sustainable catches also benefit consumers of fish. These benefits, however, will not materialize if the impact of the fuel price increase is neutralized by inadvisable financial subsidies to the fishing industry
Taxation of European Farmers La fiscalité des agriculteurs européens Die Besteuerung der Landwirte in Europa
Authors: Hill Berkeley , Cahill Carmel 
Published: May 2007

summaryTaxation of European FarmersThe special treatments that farmers and landowners receive in national systems of taxation and social security are a little‐studied way in which governments are involved with agriculture and provide it with support. As policy instruments they can be an alternative to programmes that involve government expenditure. A recent OECD inventory covering taxes on income, property (annual, transfers and capital gains) and inputs (such as duty on fuel) has found that special treatments of agriculture are widespread in Europe, mostly in the form of concessions relative to the arrangements applied to other industries and occupations. They represent an accumulation of responses to particular problems, many of which have receded into history. But once in place special treatments are often difficult to remove. Agricultural concessions influence the pattern of production in the short‐term and the structure of the industry and its output in the longer term. The present inventory reveals inconsistency and contains conflicts with other policy aims. The lack of transparency and difficulty of establishing clearly what is a preferential treatment, together with important information gaps, suggests that further study and evaluation of tax concessions is required. Nevertheless, special treatment of agriculture is too important to be ignored.
Ethanol Transforms Agricultural Markets in the USA L'éthanol transforme les marchés agricoles aux Etats‐Unis Ethanol transformiert die Agrarmärkte in den USA
Authors: Westhoff Pat , Thompson Wyatt , Kruse John , Meyer Seth 
Published: May 2007

summaryEthanol Transforms Agricultural Markets in the USAIn the United States the volume of ethanol produced from maize is increasing at a very fast rate. The high crude oil prices explain some of this growth, but government policies have also been instrumental by fostering the growth of the US ethanol industry. Tax credits and import tariffs have encouraged investment by increasing ethanol producer returns, while at the same time environmental regulations and mandated levels of renewable fuel use have encouraged, if not required, gasoline blenders to use ethanol. The growing biofuel industry has resulted in closer links between energy and agricultural markets more than ever before. Prices for maize and other grains have increased, feed rations have changed, and the expected taxpayer cost of traditional US farm commodity programs has sharply declined. In 2006, high petroleum prices along with supportive policies contributed to record high US ethanol prices and massive investment in even greater production capacity. The immediate implications for the European Union are higher world commodity prices as maize is reallocated to ethanol production. As biofuels represent a larger share of motor fuel use in the US than in the EU, the US experience is a useful point of comparison as EU energy policies are developed.
Acute exercise markedly increases blood oxidative stress in boys and girls
Authors: Nikolaidis Michalis G. , Kyparos Antonios , Hadziioannou Marina , Panou Neraida , Samaras Leonidas , Jamurtas Athanasios Z. , Kouretas Dimitris 
Published: May 2007

This study investigated the effect of an acute swimming protocol on selected blood redox status indices in trained children. Eleven boys and 11 girls (aged 9–11 y) swam 12 bouts of 50 m at a pace corresponding to 70%–75% of the participant’s 50 m maximum velocity, with each bout separated by 1 min rest periods. At rest, no differences in any redox status marker between boys and girls were observed. As compared with the pre-exercise values, significant increases in thiobarbituric acid-reactive substances (TBARS), protein carbonyls, catalase activity, total antioxidant capacity (TAC), and oxidized glutathione (GSSG) concentration, as well as significant decreases in reduced glutathione (GSH) concentration and GSH:GSSG, were found post-exercise in both boys and girls. The magnitude of the exercise-induced alterations in the blood redox status based on the calculated effect sizes could be considered large for all parameters in both sexes (median effect size in absolute values was equal to 1.38). The main finding of the present study is that an acute swimming bout at 70%–75% maximum velocity resulted in blood oxidative stress in a similar manner in both trained young boys and girls.
Arterial stiffness following repeated Valsalva maneuvers and resistance exercise in young men
Authors: Heffernan Kevin S. , Jae Sae Young , Edwards David G. , Kelly Erin E. , Fernhall Bo 
Published: May 2007

The purpose of this study was to compare arterial stiffness after a bout of resistance exercise (RE) and an experimental condition consisting of repeated Valsalva maneuvers (VMs). Fourteen male participants randomly completed a lower-body, unilateral RE bout and a VM bout designed to alter blood pressure (BP) in a similar pulsatile fashion. Pulse-wave velocity (PWV, measured in metres per second (m·s–1)) was used to measure central and peripheral arterial stiffness and was assessed before and 20 min after each perturbation. Beat-to-beat blood pressure (BP) was assessed during bouts using finger plethysmography. Change in systolic BP, diastolic BP, mean arterial pressure, and pulse pressure were similar during both bouts. Central PWV increased after repeated VMs (7.1 ± 0.3 m/s to 7.8 ± 0.3 m/s), but not after RE (7.2 ± 0.3 m/s to 7.2 ± 0.3 m/s) (interaction, p = 0.032). There was no change in peripheral PWV after VM (8.9 ± 0.3 m/s to 9.3 ± 0.3 m/s) or RE (8.5 ± 0.2 m/s to 8.4 ± 0.2 m/s). Arterial stiffness increased after repeated VM. Even though presented with a similar BP load, arterial stiffness did not increase after acute RE. These findings suggest a role for VM in acutely altering arterial properties.
Association of insulin sensitivity and muscle strength in overweight and obese sedentary postmenopausal women
Authors: Karelis Antony D. , Tousignant Benoit , Nantel Julie , Proteau-Labelle Majorique , Malita Florin M. , St-Pierre David H. , Brochu Martin , Doucet Eric , Rabasa-Lhoret Rémi 
Published: May 2007

The objective of this study was to examine the relationship between insulin sensitivity and lower body muscle strength in overweight and obese sedentary postmenopausal women. The design of the study was cross-sectional. The study population consisted of 82 non-diabetic overweight and obese sedentary postmenopausal women (age: 58.2 ± 5.1 y; body mass index (BMI): 32.4 ± 4.6 kg·m–2). Subjects were classified by dividing the entire cohort into quartiles based on relative insulin sensitivity expressed per kilograms of lean body mass (LBM) (Q1, < 10.3, vs. Q2, 10.3–12.4, vs. Q3, 12.5–14.0, vs. Q4, >14.0 mg·min–1·kg LBM–1). We measured insulin sensitivity (using the hyperinsulinemic–euglycemic clamp technique), body composition (using dual-energy X-ray absorptiometry), visceral fat and muscle attenuation (using computed tomography), and a lower-body muscle strength index expressed as weight lifted in kilograms per kilogram of LBM (kg·kg LBM–1) (using weight-training equipment). A positive and significant relationship was observed between insulin sensitivity and the muscle strength index (r = 0.37; p < 0.001). Moreover, a moderate but significant correlation was observed between the muscle strength index and muscle attenuation (r = 0.22; p < 0.05). Finally, the muscle strength index was significantly higher in the Q4 group compared with the Q2 and Q1 groups, respectively (3.78 ± 1.13 vs. 2.99 ± 0.77 and 2.93 ± 0.91 kg·kg LBM–1; p < 0.05). Insulin sensitivity is positively associated with lower-body muscle strength in overweight and obese sedentary postmenopausal women.
Does Drug-target Have a Likeness?
Authors: Xu H. , Fang Y. , Yao L. , Chen Y. , Chen X. 
Published: May 2007

Summary

Objective:
The discovery of new targets that are sufficiently robust to yield marketable therapeutics is an enormous challenge. Conventional target identification approaches are disease-dependent, which require heavy experimental workload and comprehensive domain knowledge. In this work, we propose that a disease-independent property of proteins, “drug-target likeness”, can be explored to facilitate the genomic scale target screening in the post-genomic age.

Methods:
ASupport Vector Machine (SVM) classifier was trained to recognize target and non-target protein sequences compiled from the Therapeutic Target Database, Drug Bank, and PFam. Protein sequences are encoded by theircomposition, transition and distribution features of residues and Gaussian kernel function was used in SVM classification.

Results:
SVM with a fine-tuned kernel width records 66.4 ± 5.1% of sensitivity and 97.2 ± 0.6% of specificity, corresponding to an overall target prediction accuracy of 94.4 ± 0.8%.

Conclusions:
Though primitive, these results suggest that, similar to the “drug likeness” for small chemicals, their binding partners, drug targets, also display shared features which are reflected in their sequences and can be captured bystatistical learning approaches. Further research on how to accurately and interpretably measure the likeness of protein being a drug target is promising. Inspired bythe progress of “drug likeness” studies, advances in protein descriptors, statistical learning algorithms and more comprehensive and accurate gold-standard data set from disease biology research may help to further define the “drug-target likeness” property of proteins.
Automatic Generation of 3D Statistical Shape Models with Optimal Landmark Distributions
Authors: Wolf I. , Meinzer H.-P. , Heimann T. 
Published: May 2007

Summary

Objectives:
To point out the problem of non-uniform landmark placement in statistical shape modeling, to present an improved method for generating landmarks in the 3D case and to propose an unbiased evaluation metric to determine model quality.

Methods:
Our approach minimizes a cost function based on the minimum description length (MDL) of the shape model to optimize landmark correspondences over the training set. In addition to the standard technique, we employ an extended remeshing method to change the landmark distribution without losing correspondences, thus ensuring a uniform distribution over all training samples. To breakthe dependency of the established evaluation measures generalization and specificity from the landmark distribution, we change the internal metric from landmark distance to volumetric overlap.

Results:
Redistributing landmarks to an equally spaced distribution during the model construction phase improves the quality of the resulting models significantly if the shapes feature prominent bulges or other complex geometry.

Conclusions:
The distribution of landmarks on the training shapes is – beyond the correspondence issue – a crucial point in model construction.
A Geometric Model of the Beating Heart
Authors: Lorenz C. , Berg J. von 
Published: May 2007

Summary

Objectives
: A comprehensive model of the human heart that covers multiple surfaces, like those of the four chambers and the attached vessels, is presented. It also contains the coronary arteries and a set of 25 anatomical landmarks. The statistical model is intended to provide a priori information for automated diagnostic and interventional procedures.

Methods
: The end-diastolic phase of the model was adapted to fit 27 clinical multi-slice computed tomography images, thus reflecting the anatomical variability to be observed in that sample. A mean cardiac motion model was also calculated from a set of eleven multi-phase computed tomography image sets. A number of experiments were performed to determine the accuracy of model-based predictions done on unseen cardiac images.

Results
: Using an additional deformable surface technique, the model allows for determination of all chambers and the attached vessels on the basis of given anatomical landmarks with an average accuracy of 1.1 mm. After such an individualization of the model by surface adaptation the centerlines of the three main coronary arteries may be estimated with an average accuracy of 5.2 mm. The mean motion model was used to estimate the cardiac phase of an unknown multislice computed tomography image.

Conclusion
: The mean shape model of the human heart as presented here complements automated image analysis methods with the required a priori information about anatomical constraints to make them work fast and robustly.
Spatially Varying Elasticity in Image Registration
Authors: Franz A. , Fischer B. , Kabus S. 
Published: May 2007

Summary

Objectives:
In this paper we are concerned with elastic image registration. Usually, elastic approaches assume constant material parameters and result in a smooth displacement field. However, a constant choice has its shortcomings for images with varying elastic properties, like bones and soft tissue. The proposed method allows forspatially varying material properties.

Methods:
The proposed variational registration scheme is based on a segmentation of the template image. Individual material properties can be assigned to each segmented region. The proposed variable elastic regulariser leads to a displacement field which is adapted to the locally chosen material properties.

Results:
The capability of this approach is demonstrated by a synthetic and by real-life examples in two dimensions. For all examples the proposed method is compared to a conventional scheme where the material parameters are constants in the entire image domain.

Conclusions:
A method for non-parametric registration which supports spatially varying elastic properties such as (in)compressibility or Young’s modulus in certain image regions is proposed. It allows for registration results to be more realistic compared to conventional approaches. Also, for a particular structure, an approximated preservation of volume or shape can be achieved.
Assimilating Vortex Position with an Ensemble Kalman Filter
Authors: Chen Yongsheng , Snyder Chris 
Published: May 2007

Abstract
Observations of hurricane position, which in practice might be available from satellite or radar imagery, can be easily assimilated with an ensemble Kalman filter (EnKF) given an operator that computes the position of the vortex in the background forecast. The simple linear updating scheme used in the EnKF is effective for small displacements of forecasted vortices from the true position; this situation is operationally relevant since hurricane position is often available frequently in time. When displacements of the forecasted vortices are comparable to the vortex size, non-Gaussian effects become significant and the EnKF’s linear update begins to degrade. Simulations using a simple two-dimensional barotropic model demonstrate the potential of the technique and show that the track forecast initialized with the EnKF analysis is improved. The assimilation of observations of the vortex shape and intensity, along with position, extends the technique’s effectiveness to larger displacements of the forecasted vortices than when assimilating position alone.