bluuebunny/crossref_metadata_2025 huggingface dataset:
Inferential and descriptive influences on measures of respiratory sinus arrhythmia: Sampling rate, R‐wave trigger accuracy, and variance estimates
Authors: RINIOLO TODD , PORGES STEPHEN W.
Published: February 2007

The use of respiratory sinus arrhythmia (RSA) is dependent on several quantification factors. The statistical consequences of sampling rate, R‐wave trigger accuracy, and the data structure of RSA estimates were evaluated via simulations and simulated modifications. Simulations demonstrated that sampling rate determined the amplitude of the smallest oscillation that could be accurately described. When the amplitude of the oscillation was smaller in milliseconds than the sampling interval, all smaller oscillations, regardless of amplitude, were indiscriminately assigned a default value defined as 50% of the sampling interval. Also, reduced R‐wave peak detection accuracy was demonstrated to influence statistical analyses. The distributional characteristics of several common methods of structuring RSA estimates were investigated, and results indicated that several methods result in asymmetrical distributions. We recommend using rapid sampling rates (i.e., 1 kHz), accurate R‐wave peak detectors, and avoiding statistical trouble.
Storage of feature conjunction in transient auditor memory
Authors: GOMES HILARY , BERNSTEIN RICHARD , RITTER WALTER , JR. VAUGHANM HERBERT G. , MILLER JEFF
Published: February 2007

The purpose of this study was to determine whether feature conjunction are stored in transient auditory memory. The mismatch negativity (MMN), an event‐related potential that is elicited by stimuli that differ from a series of preceding stimuli was used in this endeavour. A tone that differed from the preceding series of stimuli in the conjunction of tow of its features, both present in preceding stimuli but in different combination, was found to elicit the MMN, the data are interpreted to indicate that information about the conjunction of feature is stored in the memory.
Event‐related potential correlates of interference between cognitive performance and tonic experimental pain
Authors: LORENZ JÜRGEN , BROMM BURKHART
Published: February 2007

In this study, we examined cognitive function during experimental pain induced by an ischemic upper‐arm tourniquet. During pain and control conditions, individuals performed a memory search task and an oddball task. Reaction time, errors, and event‐related potentials in response to task stimuli were evaluated. Pain reduced accuracy and changed the response‐type dependency of errors and the reaction time within the memory search task: false rejections but not false acceptances increased, and rejections were faster than acceptances during pain, whereas the opposite occurred during control conditions. The memory probes elicited an N275 that increased and a P300 that decreased in amplitude during pain. Pain also reduced amplitudes of P200 and P300 from the oddball task. N275 enhancement was greater in nonaffected than affected individuals, suggesting its association with focused attention that inhibited disruption by pain. P300 attenuation is interpreted as an indication that cognitive involvement in pain diminishes the attention resources allocated to a concurrent cognitive task.
The concurrent recording of electroencephalography and impedance cardiography: Effects on EEG
Authors: DALTON KIM M. , DAVIDSON RICHARD J.
Published: February 2007

Three experiments were performed testing the effects of a variety of impedance cardiograph electrode types and recording arrangements on recorded electroencephalography (EEG) using either a monopolar single‐ear reference or a physically linked ears reference. EEG was recorded either alone or concurrently with an impedance cardiograph. When the cardiograph was recorded using a spot electrode for the top current‐inducing electrode, there was an overall decrease in power density of the EEG, and this effect was dependent on the location of the recording electrode. This effect was diminished when the top cardiograph spot electrode was replaced by a mylar‐coated neck band electrode and EEG was recorded using a monopolar, single‐ear reference. However, there tended to be an overall increase in log power density of the EEG in each frequency band below 60 Hz when less technologically advanced EEG amplifiers were used. This effect was diminished if the EEG was recorded using a physically linked ears reference. Recommendations for the concurrent recording of EEG and impedance cardiography are discussed.
Probe P3 and blinks: Two measures of affective startle modulation
Authors: SCHUPP HARALD T. , CUTHBERT BRUCE N. , BRADLEY MARGARET M. , BIRBAUMER NIELS , LANG PETER J.
Published: February 2007

Two concurrent measures of the evoked startlé response, the elicited blink reflex and the event‐related potential, were measured while individuals viewed pictures that varied in pleasure and arousal. Replicating previous findings, the blink response was modulated by picture pleasantness, with larger reflexes elicited in the context of viewing unpleasant versus pleasant pictures. However, the probe P3 was primarily modulated by picture arousal, with smaller P3 responses elicited when viewing affective (pleasant or unpleasant) than when viewing neutral pictures. Both modulatory effects were sustained for probes presented in a subsequent picture imagery period. These data suggest that two measurable responses to the same startle probe are differentially modified by emotional context, with blink magnitude varying with pleasure and probe P3 varying with stimulus arousal.
Localization of word and face recognition memory using topographical EEG
Authors: BURGESS A. P. , GRUZELIER J. H.
Published: February 2007

The aim of this study was to explore the ability of epoch‐averaged electroencephalogram (EEG) to localize cognitive functions. The EEG was recorded in healthy individuals performing a task where, on the basis of evidence from other functional brain imaging techniques, there was a high expectation of where functional changes would be expected. Topographical EEG was recorded while individuals performed recognition memory tasks for words and faces. Comparison of the acquisition and recognition phases of the experiment showed significant attenuation of alpha, betal, and beta2 in the right temporoparietal region for the faces but no significant changes for words. Left temporoparietal changes for the word task were only seen among the women. The results confirmed the validity of EEG for use in the localization of cognitive function for faces for men and women but in the case of words for the women only.
Review of information on lime loss and changes in soil pH gained from ADAS experiments
Authors: Chalmers A. G.
Published: February 2007

Abstract. Data on lime loss and soil acidification obtained from a range of ADAS experiments are reviewed. The trials, which include drainage and lysimeter studies and long‐term liming, manuring and soil management experiments, indicate a wide range of annual lime losses, with maximum rates in excess of 1000 kg ha−1 CaCO3.
On the causes of decline of Norway spruce (Picea abies Karst.) in Central Europe
Authors: Rehfuess K. E.
Published: February 2007

Abstract. A careful study of the etiology and symptoms of the decline phenomena in stands of silver fir (Abies alba Mill.), Scots pine (Pinus sylv L.), European beech (Fagus silv. L.) and Norway spruce (Picea abies Karst.) in southern Germany leads to the conclusion that all these diseases, although exhibiting some common features (e.g. premature senescence and shedding of leaves, formation of transparent crowns), vary considerably between species and, within one particular species, between forest regions. It therefore seems plausible to assume, as a first approach, that we have to deal with different types of disease or decline, and consequently also with varying sets of causes or stress factors. This approach can be demonstrated best by reviewing the present knowledge of diseases in Norway spruce.
Comparative measures of effectiveness in farm‐level soil conservation
Authors: Saliba B. Colby
Published: February 2007

Abstract. Agricultural soil erosion is serious in developed and developing countries alike. Soil runoff can diminish long‐term land productivity and accompanying sedimentation of waterways contributes to flooding and substantially reduces both water quality and the useful life of reservoirs and irrigation works. To design effective erosion control policies, planners need to be able to evaluate conservation efforts by fanners. The research reported here develops comparative measures of conservation effectiveness using the management factors of the Universal Soil Loss Equation. These factors measure the effectiveness of farmers' existing conservation practices and can help policymakers identify the regions and types of farms which are not using effective erosion control measures, enabling them to direct scarce personnel and funds to areas where they are most needed.
Soil management under urban‐fringe farming systems in Freetown, Sierra Leone
Authors: Millington A.C.
Published: February 2007

Abstract. An example is given of urban fringe farming from Freetown, Sierra Leone, where immigrants practise intensive cultivation in an environmentally marginal situation. Great reliance is placed on farming experience, generally gained from rural areas, before migration to Freetown. Two main problems result; declining soil fertility and increased erosion hazards. Lack of government recognition of these farmers means that indigenous, innovative solutions to overcome these problems are being formulated.
Effect of incorporation of crop straw residues on the yield of mustard and wheat
Authors: Bahl G. S. , Pasricha N. S. , Aulakh M. S. , Baddesha H. S.
Published: February 2007

Abstract The effect of incorporating straw of Vigna radiata L. (moong) into the soil at 3.2 t ha‐1 on the grain yields of mustard and wheat was investigated with and without 0, 50 and 100% of optimum levels of fertilizers (100 kg N + 50 kg P2O3 ha‐1 for mustard and 125 kg N + 62.5 kg P2O3+ 30 kg k2O ha‐1 for wheat). In the two‐year field experiment, the incorporation of moong residue reduced the grain yield of mustard by 24 to 31% and wheat by 13 to 17%. This adverse effect was, however, diminished with the application of fertilizers. It was concluded that management of crop residues is possible without any adverse effect on the subsequent crop yield when incorporated with adequate levels of N and P fertilizers.
Mole drainage of a Hallsworth Series soil
Authors: Armstrong Adrian C.
Published: February 2007

Abstract. Mole drainage of the Hallsworth Series was compared to a traditional treatment of drains alone at 12 m spacing. It is demonstrated that mole drainage offers superior control of water tables and reduces surface run‐off. Some management implications of these results are discussed.
Nitrate leaching from a felled Sitka spruce plantation in Beddgelert Forest, North Wales
Authors: Stevens P.A. , Hornung M.
Published: February 2007

Abstract. Soil water samples from five horizons in a stagnopodzol were collected regularly over a five‐year period in a Sitka spruce plantation at Beddgelert Forest, North Wales. Samples were analysed for nitrate‐N and ammonium‐N. After felling, inorganic‐N concentrations increased markedly in the C horizon, generally decreased in the surface horizons and showed little change in the E and Bs horizons. Fluxes through the C horizon increased after felling from 10 to 70 kg N ha‐1 a‐1, the latter being equivalent to leaching losses in intensive lowland agricultural systems. Trends in concentration and flux were attributed to seasonal temperature and rainfall variations.

Nitrate‐N dominated the dissolved inorganic‐N, especially in the lower horizons. Nitrification was obviously active, despite the acid soil. Nitrate leaching losses occurred, even beneath the standing crop. On felling, cessation of nitrogen uptake allowed substantially more nitrate to be leached as no alternative sink was immediately available.
Predicting the average movement of reactive solutes in soils
Authors: Bond W.J. , Smiles D.E.
Published: February 2007

Abstract. Simple equations are presented to predict the movement of a solute front in response to a given net cumulative flux of water. These equations do not require the assumption that the water content is at field capacity following water inflow, but may be simplified to that case. Equations are presented both for inert solutes and for anions and cations that react with soils through which they pass. The use of the equations is illustrated with simple hypothetical examples and, in one case, with field data.
The leaching of salts from restructured saline clay soils
Authors: Tanton T.W. , Armstrong A.S.B. , Rycroft D.W.
Published: February 2007

Abstract. The leaching of salt from a restructured saline heavy montmorillonite clay soil was studied experimentally. Restructured clay was placed in a 25‐m long ± 0.75‐m deep polythene‐lined trench and leaching studied under flood irrigation. The hydraulic conductivity of the soil always exceeded 25 m d‐1 during the experiment, and 85 % of the salt was leached within 16 days, most being leached in the first 8 days. The results indicate that restructuring clay could make the drainage of heavy clay soils economically feasible.
Toxic metals in amenity soil
Authors: Bridges E.M.
Published: February 2007

Abstract. The soil of amenity areas is important in the urban landscape. Some is natural, some is man‐made. Both contribute greatly to the environment of our cities through the grass, shrubs and trees which they support. Results of research from agriculture and urban gardens have been extrapolated in this review to consider the significance of toxic metals in amenity soil. The metals of most concern for plant growth are zinc, copper and nickel as they are phytotoxic, but additionally lead, cadmium, arsenic, and mercury are of concern due to their effects on human health. The currently acceptable threshold values for metals in the soil of public open spaces, playing fields and parks are presented, and consideration is given to the toxic metal content of an assortment of materials likely to be used in constructing amenity soil.
The drainage of restored opencast coal sites
Authors: Hodgkinson R.A.
Published: February 2007

Abstract. The soil conditions both before and after restoring opencast sites and their effect on drainage and crop growth are discussed both in general and with specific reference to the site concerned. Both drainage treatments showed a benefit over the undrained control, although no extra benefit was observed from drains at 20‐m spacing with mole drains and subsoiling compared to drains at 40‐m spacing with mole drains. Subsoiling reduced bulk density and increased surface infiltration rates, but improvements to the soil brought about by subsoiling were short‐lived.
The retention of nitrate in acid soils from the tropics
Authors: Wong M.T.F. , Hughes R. , Rowell D.L.
Published: February 2007

Abstract. In most soils of temperate regions nitrate is not held on soil surfaces and moves freely in solution. But when soils carry positive charges, nitrate is held as an exchangeable anion. As a result, leaching of nitrate is delayed relative to the movement of water. The delay can be predicted provided the anion exchange capacity (AEC) can be measured and the concentration of counter‐anions is known. For soils with variable charge, the AEC varies with both pH and ionic strength, and the effective AEC should be determined under conditions similar to those in soil solution. A simple leaching method is described which satisfies this requirement. Delays in the leaching of nitrate measured in columns of repacked soil were strongly related to the AEC.
Autotrophic and heterotrophic mechanisms for ammonia oxidation
Authors: Wood P.M.
Published: February 2007

Abstract. Autotrophic nitrifiers such as Nitrosomonas use ammonia mono‐oxygenase for the initial stage of ammonia oxidation. Nitrification inhibitors have this enzyme as their site of action. Their mechanisms include alternative substrates, suicide substrates and cuprous copper chelators.

In heterotrophs, organic nitrogen is normally in the fully reduced state, but a few cell metabolites contain N‐O bonds. The synthesis and breakdown of such compounds provides a mechanism for heterotrophic nitrification. A non‐enzymic mechanism for nitrogen‐oxidation involves hydroxyl radicals produced by the Fenton reaction. Heterotrophic nitrification is particularly important in woodland soils, where wood‐rotting fungi use free radicals to break down lignin. Tests for a radical mechanism are described.
The Rothamsted soil and crop nitrogen service on Viewdata 1985–1989
Authors: Whitmore A.P. , Bland G.J. , Addiscott T.M.
Published: February 2007

Abstract. During the four consecutive winters between 1984 and 1989 a computer simulation model was used to estimate the amounts of nitrogen in a cereal crop and available from soil to the crop after winter. The model does this by taking account of daily weather and by making simple assumptions about the starting conditions each autumn after the harvest of the previous crop. Some of the information which was given to farmers on viewdata systems is displayed, together with maps showing the average amounts of nitrogen in soil and crop in spring over 10 years in eastern England. This 10‐year average is used as a baseline against which to judge the simulations in each of the four winters of our viewdata service.
Cattle trampling and soil compaction on loamy sands
Authors: Mulholland B. , Fullen M. A.
Published: February 2007

Abstract. Field investigations on loamy sand soil showed that compaction by cattle trampling increased soil bulk density and cone penetrometer resistance. Trampling produced very dense zones at depths of 7–10.5 cm, which impeded drainage, despite the presence of large macropores. Soil structural and hydrological changes caused by hoof compaction can result in serious pasture management problems. Compaction simulation experiments on saturated turf indicated that most severe structural damage occurs on initial compaction.
Nitrate leaching and intensive outdoor pig production
Authors: Worthington T. R. , Danks P. W.
Published: February 2007

Abstract. The production of pigs in outdoor units is gaining in popularity in the United Kingdom and is often concentrated on free‐draining soils over important aquifers. Originally, stocking rates were sufficiently low to ensure the maintenance of a grass crop, but recently they have increased. Pigs are natural ‘rooters’ and wallowers and so cause damage to vegetation and soil structure. With overstocking these natural activities lead to considerable areas of bare, uncropped ground for much of the year. This paper assesses the potential for leaching of nitrate from such land, and makes recommendations for decreasing it.
Nutrient balances in calcareous soils after application of different rates of pig slurry
Authors: Bernal M. P. , Roig A. , García D.
Published: February 2007

Abstract. Changes in amounts of macro‐(N, P, K) and micro‐nutrients (Fe, Mn, Zn and Cu) were determined in two calcareous soils amended over an eight‐month period with pig slurry applications ranging from 0 to 500 m3/ha, and planted in containers with green pepper (Capsicum annuum). Total N and exchangeable K increased after slurry applications of 300 m3/ha or more, and available P increased after the smallest application rate (100m3/ha). Maximum crop nutrient uptakes of 41, 40 and 91% for N, P and K occurred with the smallest dose of slurry. Large losses of N, ranging from 27 to 74% (mean 55%) of N added to soil, occurred with all slurry treatments. From 41 to 71% (mean 55%) of the total P added in pig slurry was fixed in non‐assimilable forms. Most of the K from the pig slurry was available to the plants. Most of the micro‐nutrients (Fe, Mn, Zn and Cu) from the slurry were immobilized in the soil, probably because of the high pH and the small amounts of organic matter in both the slurries and soils tested.
Evaluating land use at the sub‐regional level in the Atlantic zone of Costa Rica, considering biophysical land potentials
Authors: Huising E.J. , Wielemaker W.G. , Bouma J.
Published: February 2007

Abstract. Soils and land use in the Atlantic Zone of Costa Rica were mapped independently at a scale of 1: 100000. At this scale, mapping units are often composite, both in terms of soil type and land utilization type. Combinations of given soil and land utilization types were produced by overlaying the soil and land use maps, on which there was 63% coincidence of unit boundaries. Each combination of land unit and land use was evaluated in terms of bio‐physical potentials. From expert judgement land use was shown to be (a) in balance with the use potential, (b) exceeding the use potential (‘over‐use’) or (c) less than the use potential (‘under‐use’). 18% of the area is over‐used, in non‐sustainable forms of land use, but 51% is under‐used and could be put to more demanding types of land use.
Nutrient fluxes in runoff on reseeded blanket bog, limed and fertilized with urea, phosphorus and potassium
Authors: Williams B.L. , Young M.
Published: February 2007

Abstract. Studies have been made of the effects of 15 g N/m2 as urea in two dressings during April and June on annual nutrient fluxes in runoff from reseeded blanket bog also receiving annually 6 g P/m2 as granular superphosphate and 6 kg K/m2 as potassium chloride. Urea applications increased significantly (P < 0.05) the mean annual ammonium‐N flux from 17 mg/m2 for the P + K plots to 245 mg/m2 for the N + P + K plots. Annual fluxes of total P, K and Ca were also increased (P < 0.05) by the addition of urea. This was attributed to the effects of increased acidity around grass roots following N uptake as ammonium‐N. In contrast, nitrate‐N was removed from rainwater throughout the year and concentrations in runoff were at the limit of detection (< 0.01 mg/1) on many occasions. Concentrations of organic‐N in runoff exceeded those of ammonium‐N, but were not significantly changed by fertilization.
Nitrate leaching as affected by long‐term N fertilization on a coarse sand
Authors: Hansen E.M. , Djurhuus J.
Published: February 2007

Abstract. A field experiment on a coarse sand (1987–92) was conducted with spring barley (Hordeum vulgare L.), in order to evaluate the effects of increasing N fertilization on nitrate leaching under temperate coastal climate conditions. The N fertilizer levels were 60 and 120 kg N/ha. The experiment was conducted on a 19‐year old permanent field trial with continuous spring barley, initiated in 1968, and included treatments with ploughing in autumn or spring, with or without perennial ryegrass (Lolium perenne L.) as a catch crop undersown in spring. Prior to 1987, the low and high levels of N fertilizer were 70 and 150 kg N/ha, respectively. To calculate nitrate leaching, soil water samples were taken from a depth of 0.8 m using ceramic cups. The average annual nitrate leaching from plots with 60 and 120 kg N/ha was 38 and 52 kg N/ha/y, respectively. The increased leaching associated with increasing fertilizer application was not caused by inorganic N in the soil at harvest, but rather by greater mineralization, mainly in autumn. Growing of a catch crop was relatively more efficient for reducing nitrate leaching than a long‐term low fertilizer application. A 50% reduction in N application decreased average yield by 26%, while nitrate leaching decreased by 27%.
A survey to assess the extent of soil water erosion in lowland England and Wales
Authors: Skinner R. J. , Chambers B.J.
Published: February 2007

Abstract. A study of soil water erosion was undertaken between 1982 and 1986 in 17 areas of lowland England and Wales. Air photographs were taken annually, these were checked to identify erosion events and a sample of 392 eroded fields visited between 1983 and 1986. Erosion was most common in fields drilled with winter cereals (39% of cases), which was the crop considered by farmers to be at greatest risk of erosion. Estimated crop losses were greater than 10% for only 5% of fields. ‘Clean up’ costs were incurred on 15% of the fields studied. Attempts at contour ploughing and planting/drilling appeared to result in more severe erosion, than working up and down the slope. Farmers considered that the main reason for erosion on their farms was arable cropping, and the presence of compacted wheelings/tramlines. Fields where hedges had been removed in the last 20 years suffered from erosion marginally more frequently than other fields. Field slope alone was not found to be a major factor in the occurrence of erosion, with almost 60% of erosion events on slopes of less than 7°. Erosion occurred at least every other year in half the fields studied.
Ionic contents of leachate from grassland soils: a comparison between ceramic suction cup samples and drainage
Authors: Hatch D. J. , Jarvis S. C. , Rook A. J. , Bristow A. W.
Published: February 2007

Abstract. Ceramic suction cups were used to obtain samples of soil solution from permanently grazed swards receiving 200 kg N/ha/y. The suction cups were installed in 1 ha plots at 10, 30 and 60 an depth in a poorly drained, heavy clay soil in S. W. England. The plots were hydrologically isolated from each other by perimeter drains which channelled surface runoff water into v‐notch weirs. In one treatment, artificial drainage by a system of field and mole drains also converged to outfalls through v‐notch weirs, which enabled samples to be taken. Nitrate and a range of other ionic constituents were examined over a 12 month period in soil solutions taken from the suction cups and compared with leachate obtained from the field drains and surface channels. Field drain samples frequently exceeded the EC limit of 11.3 mg nitrate‐N/1, but concentrations in suction cups obtained during the same period did not, and were up to ten‐fold less. Although correlations for ions were found between different sampling depths and drainage samples, no clear patterns emerged. It was concluded that suction cups were inappropriate for the determination of the overall leaching losses in this soil type, but provided useful data on changes in ionic concentrations which occurred in different soil horizons through to drainage outfalls.
Amelioration of a degraded Oxic Paleustalf by leguminous and natural fallows
Authors: Kang B. T. , Salako F. K. , Akobundu I. O. , Pleysier J. L. , Chianu J. N.
Published: February 2007

Abstract. The restorative ability of herbaceous (Psophocarpus palustris, Pueraria phaseoloides) and woody (Leucaena leucocephala, Senna siamea, Acacia leptocarpa, Acacia auriculiformis) legume species and of natural regrowth was studied on an eroded and compacted Oxic Paleustalf in southwestern Nigeria. Compared to the control treatment that was continuously cropped for 15 years, four years of fallowing significantly improved test crop yields. However, fallowing with the above species did not substantially improve soil properties, particularly soil bulk density. A longer fallow period may be needed to amend soil physical conditions of this degraded Alfisol. Soil chemical properties were greatly improved following land clearing and plant biomass burning in 1993. However, the residual effect of burning on soil fertility was insignificant in the second cropping year. Among the fallow species, P. palustris and natural fallow showed the best residual effect on test crop performance. Despite the high biomass and nutrient yields of S. siamea and A. auriculiformis, test crop yields on these plots were low due to the border effects from the uncleared and fallowed subplots.
Changes in soil profile characteristics through cultivation of an upland Vertisol in Zambia
Authors: Mulonga W. , Deckers J. , Feyen J.
Published: February 2007

Abstract. Crops grown on virgin upland Vertisols of Zambia, are reported to perform rather poorly. However, subsoiling followed by repeated cultivation over two years apparently improves crop growth. Highest yields were recorded under long‐term cultivation (12 years). To evaluate the reasons for these differences in crop response to Vertisol management, physical and hydrodynamic characteristics of soil profiles were studied in three soil management systems. The management systems were: uncultivated or virgin land; land cultivated for two years; and land cultivated for 12 years. The mean soil aggregate size decreased with increased time of cultivation, mostly due to the decrease of the largest sized aggregates. The surface horizon dried more slowly on the long‐term cultivation plot. A comparison of the hydraulic conductivities indicated that water intake in the deeper layers improved with increased period in cultivation. Oxygen diffusion measurements showed good aeration at field capacity, to a depth of 0.32m on the long‐term cultivation plots, but only to 0.17 m and 0.25 m for 2 years cultivation and virgin plots respectively. Repeated cultivation was beneficial in improving surface soil tilth and in improving subsurface drainage, thus removing the problem of a perched water table which occurred close to the soil surface under natural conditions.
Remediation of a sandy soil artificially contaminated with copper using a polyacrylate polymer
Authors: Torres M. O. , De Varennes A.
Published: February 2007

Abstract. We investigated whether a Na‐K polyacrylate polymer could be used to remediate a sandy soil artificially contaminated with copper. An experiment, carried out in solution culture, showed that ionic copper was rapidly trapped within the polymer to a maximum content of c. 190mg Cu g ‐1 dry polymer, the proportion needed for chelation of each copper ion by four carboxylic groups present in the polymer chains. Cu‐EDTA was not retained by the polymer. Growth of perennial rygrass in 10 kg pots was stimulated in the gel‐amended soil, and even in the pots with the highest levels of copper, growth was much less impaired than in pots without polymer. Copper concentrations of the shoot.; were smaller in the plants cultivated in the amended soil. Water extractable copper was considerably reduced in the contaminated gel‐amended soil and polymer particles removed from the soil were shown to contain high levels of copper.
Phosphorus loss from agricultural catchments: pathways and implications for management
Authors: Johnes P. J. , Hodgkinson R. A.
Published: February 2007

Abstract. The contribution non‐point P sources make to the total P loading on water bodies in agricultural catchments has not been fully appreciated. Using data derived from plot scale experimental studies, and modelling approaches developed to simulate system behaviour under differing management scenarios, a fuller understanding of the processes controlling P export and transformations along non‐point transport pathways can be achieved. One modelling approach which has been successfully applied to large UK catchments (50‐350km2 in area) is applied here to a small, 1.5 km2 experimental catchment. The importance of scaling is discussed in the context of how such approaches can extrapolate the results from plot‐scale experimental studies to full catchment scale. However, the scope of such models is limited, since they do not at present directly simulate the processes controlling P transport and transformation dynamics. As such, they can only simulate total P export on an annual basis, and are not capable of prediction over shorter time scales. The need for development of process‐based models to help answer these questions, and for more comprehensive UK experimental studies is highlighted as a pre‐requisite for the development of suitable and sustainable management strategies to reduce non‐point P loading on water bodies in agricultural catchments.
Intensified Screening and Treatment of the Metabolic Syndrome for Cardiovascular Risk Reduction
Authors: Wong Nathan D.
Published: February 2007

The metabolic syndrome (MetS), characterized by a clustering of risk factors associated with insulin resistance and abdominal obesity, is associated with an increased risk of coronary heart disease and cardiovascular disease mortality. Persons with MetS have a wide spectrum of coronary heart disease risk and appropriate evaluation of risk using global risk algorithms. Measurement of other risk markers and subclinical disease is potentially needed to best set treatment goals and accompanying treatment regimens. The presence of MetS risk factors should be considered in global risk assessment. Clinical management emphasizes addressing underlying risk factors predisposing to MetS‐specifically overweight/obesity and physical inactivity. Further recommendations are given for clinical risk factors, including atherogenic dyslipidemia, elevated blood pressure, insulin resistance/hyperglycemia, prothrombotic state, and proinflammatory state. Clinicians are recommended to assess MetS in their routine practice and to intensify efforts to adequately treat accompanying lifestyle and clinical risk factors.
Different Effects of Atherogenic Lipoproteins and Blood Pressure on Arterial Structure and Function: The Bogalusa Heart Study
Authors: Chen Wei , Srinivasan Sathanur R. , Li Shengxu , Berenson Gerald S.
Published: February 2007

Differential impact of non–high‐density lipoprotein cholesterol (total cholesterol minus high‐density lipoprotein cholesterol) and blood pressure on arterial wall thickness and stiffness was examined in 900 black and white adults aged 24–43 years. Blacks compared with whites had greater values of pulse wave velocity (5.4 m/sec vs. 5.2 m/sec; p<0.01) and carotid artery intima–media thickness (0.83 mm vs. 0.80 mm; p<0.01). Non–high‐density lipoprotein cholesterol was significantly associated with carotid intima–media thickness (standardized regression coefficient [b]=0.21; p<0.01), but not with pulse wave velocity (b=0.03; p=0.37), after adjusting for race, sex, age, body mass index, insulin, glucose, and smoking. Systolic blood pressure was associated significantly stronger with pulse wave velocity (b=0.36; p<0.01) than with carotid intima–media thickness (b=0.15; p<0.01). No race difference in these relationships was found. The results of this study indicate that atherogenic lipoproteins and blood pressure may play different roles in the development of arterial wall stiffness and atherosclerosis.
Fibrates in Combination With Statins in the Management of Dyslipidemia
Authors: Jacobson Terry A. , Zimmerman Franklin H.
Published: February 2007

While elevated low‐density lipoprotein cholesterol is the primary target of hypercholesterolemia treatment, high triglycerides and low high‐density lipoprotein cholesterol are also important targets for therapy. Correcting these lipid abnormalities should be an integral part of therapy in hypertensive individuals. Medications such as the fibrates are effective and well tolerated for reducing triglycerides and increasing high‐density lipoprotein cholesterol, and their use has resulted in a reduction in cardiovascular events. Fibrates are also recommended as adjunct therapy for patients receiving statins whose low‐density lipoprotein cholesterol or non‐high‐density lipoprotein cholesterol is not reduced to goal levels. The combination of a statin and a fibrate may, however, raise the risk of myopathy and rhabdomyolysis. Gemfibrozil, one of the fibrates, but not fenofibrate, interferes with statin glucuronidation, which may increase the risk of myopathydue to elevations in statin serum levels. This may at least partially explain the lower incidence of myopathy with fenofibrate compared with gemfibrozil when combined with statins. Combination therapy with a fibrate and a statin is a potentially useful therapy for patients with atherogenic lipid profiles, for which fenofibrate appears to be a more appropriate choice due to less myopathic potential.
Hypertension in Older People: Part 2
Authors: Franklin Stanley S.
Published: February 2007

There is overwhelming evidence that pharmacologic treatment of isolated systolic hypertension (ISH) (systolic blood pressure ≥140 mm Hg and diastolic blood pressure <90 mm Hg) reduces cardiovascular events and extends longevity in the elderly; in the very old (80 years or older), the evidence supports decreased incident stroke and heart failure, but is less convincing in terms of longevity. Thus, the inherent increased risk for ISH vascular events highlights the importance of its control. Importantly, ISH in the elderly, primarily related to large artery stiffness, remains more difficult to control than diastolic hypertension in the young, which is primarily related to increased peripheral vascular resistance. Appropriate lifestyle and pharmacologic intervention is indicated in individuals with systolic blood pressure ≥140 mm Hg in general and ≥130 mm Hg in persons with diabetes or chronic kidney disease. Lifestyle intervention may reduce the need for extensive antihypertensive therapy and minimize associated cardiovascular risk factors. To date, only a small percentage of older ISH patients are being treated to goal. Reaching target systolic blood pressure levels most often requires the use of polypharmacy that includes a diuretic and perhaps specific agents that target arterial stiffness and early wave reflection.
Blood Pressure Components in Clinical Hypertension
Authors: Safar Michel E. , Smulyan Harold
Published: February 2007

This review offers a critical evaluation of the remarkable progress in antihypertensive therapy since its inception. Despite the introduction of newer, more sophisticated drugs, treatment results have remained stable. Problems impeding further improvement include limited patient compliance, clinical inertia, incomplete adherence to guidelines, and dependence on brachial artery cuff pressures for diagnosis, risk assessment, and treatment response. Brachial artery systolic and pulse pressures do not reliably represent aortic or carotid artery pressures, which are better risk predictors for the heart and brain. Mean pressure, which is the same throughout the arterial tree, is directly measurable by cuff oscillometry, and might become the best single risk predictor. Available drugs have limited ability to decrease the aortic stiffness that is responsible for the elevated systolic blood pressure of aging. Therefore, to improve risk assessment and therapeutic benefit, we might include mean blood pressure and pulse pressure into blood pressure measurements, pursue efforts to measure central blood pressure, and search for new drugs to reduce arterial stiffness.
Mechanism of Angiotensin II Type 1 Receptor Blocker Action in the Regression of Left Ventricular Hypertrophy
Authors: Kjeldsen Sverre E. , Strand Arne , Julius Stevo , Okin Peter M.
Published: February 2007

Left ventricular hypertrophy refers to a pathologic increase in left ventricular mass and is associated with an increased risk of subsequent cardiovascular morbidity and mortality from any cause. In the development of left ventricular hypertrophy there is growth of cardiomyocytes and accumulation of extracellular matrix and fibrosis. The actions are partly induced by angiotensin II, the principal effector of the renin‐angiotensin‐aldosterone system, binding to the AT1 receptor. Biochemical markers, some implicated in inflammatory changes, correlate with changes in left ventricular mass. The reduction in left ventricular mass brought about with angiotensin‐converting enzyme inhibitor or angiotensin receptor blocker (ARB) therapy correlates with a reduction in these inflammatory changes, monitored by brain natriuretic peptide. Recent studies incorporating trials of ARBs have found ARBs to be more effective in reducing left ventricular mass than β blockers and possibly more effective than calcium antagonists. Initial studies suggest that ARBs and angiotensin‐converting enzyme inhibitors may have similar effects in terms of reducing left ventricular hypertrophy, and the combination of angiotensin‐converting enzyme inhibitors and ARBs is thought to be synergistic due to a more complete inhibition of the renin‐angiotensin‐aldosterone system. In conclusion, these agents are efficacious in antihypertensive therapy and can play an important role in the prevention or regression of left ventricular hypertrophy due to hypertension.
Atherosclerotic Renal Artery Stenosis and Renovascular Hypertension: Clinical Diagnosis and Indications for Revascularization
Authors: Carter Barry L. , Hartz Arthur , Bergus George , Dawson Jeffrey D. , Doucette William R. , Stewart Janyce J. , Xu Yinghui
Published: February 2007

The purpose of this study was to evaluate the cross‐sectional relationship between physician knowledge of hypertension guidelines and blood pressure (BP) control. The authors evaluated a sample of primary care faculty (n=32) and a sample of their patients (n=613). When treating patients as independent observations, the authors found an inverse relationship (r=−0.524; p=0.002) where higher knowledge scores were associated with lower BP control. The authors conducted a multivariate analysis to accommodate the non‐independence due to random physician effects and found that there was no longer a significant association between knowledge and BP control, but there was still a trend (odds ratio=0.84; p=0.130). This study demonstrates that there is no evidence that high knowledge of hypertension guidelines will improve BP control rates and that higher knowledge may actually be associated with lower BP control. Strategies that are designed only to improve knowledge of hypertension guidelines are insufficient to improve BP control rates.
Expert Panel Discussion The ASCOT Trial—Are β‐Blockers Still Useful as Antihypertensive Medication?
Authors: Moser Marvin , Giles Thomas D. , Pickering Thomas G. , Victor Ronald G.
Published: February 2007

Following a hypertension symposium in New York, NY in March 2006, an expert panel was convened to discuss the Anglo‐Scandinavian Cardiac Outcomes Trial (ASCOT) and the future of β‐blocker therapy. Dr Marvin Moser of the Yale University School of Medicine, New Haven, CT chaired the panel, which included Dr Thomas D. Giles, President of the American Society of Hypertension and Professor of Medicine at Louisiana State University School of Medicine, New Orleans, LA; Dr Thomas G. Pickering, Director of Behavioral Cardiovascular Health at Columbia University College of Physicians and Surgeons, New York, NY; and Dr Ronald G. Victor, Professor of Internal Medicine and Division Chief of Hypertension at the University of Texas Southwestern Medical Center, Dallas, TX.
Efficacy and Safety of Irbesartan/HCTZ Combination Therapy As Initial Treatment for Rapid Control of Severe Hypertension
Authors: Neutel Joel M. , Franklin Stanley S. , Oparil Suzanne , Bhaumik Amitabha , Ptaszynska Agata , Lapuerta Pablo
Published: February 2007

Severe hypertension is difficult to control. This prospective, randomized, double‐blind, active‐controlled, multicenter trial compared efficacy and safety of once‐daily irbesartan/hydrochlorothiazide (HCTZ) combination therapy with irbesartan monotherapy in severe hypertension. Patients who were untreated or uncontrolled on monotherapy (seated diastolic blood pressure [BP] ≥110 mm Hg) received fixed‐dose irbesartan 150 mg/HCTZ 12.5 mg combination therapy for 7 weeks, force‐titrated to irbesartan 300 mg/HCTZ 25 mg at week 1 (n=468); or irbesartan 150 mg monotherapy, force‐titrated to 300 mg at week 1 (n=269). Significantly more patients on combination therapy achieved seated diastolic BP <90 mm Hg at week 5 (primary end point) compared with monotherapy recipients (47.2% vs 33.2%; P=.0005). Likewise, significantly more patients attained goals per the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) (<140/90 mm Hg) at week 5 (34.6% vs 19.2%, respectively; P<.0001), while the mean difference between combination and monotherapy in seated diastolic BP and seated systolic BP was 4.7 mm Hg and 9.7 mm Hg (P<.0001). Greater and more rapid BP reduction with irbesartan/HCTZ was achieved without additional side effects.
Prehypertension—What Is It and Should It Be Treated?
Authors: Moser Marvin , Giles Thomas D , Izzo Joseph L , Black Henry R
Published: February 2007

In May 2006, a panel of experts was assembled during the meeting of the American Society of Hypertension, Inc to discuss the diagnosis and treatment of prehypertension. Is it a real entity? Does it pose a risk? Should it be treated entirely with lifestyle interventions or should some patients be placed on pharmacologic therapy? The panel was chaired by Dr Marvin Moser, Clinical Professor of Medicine at the Yale University School of Medicine, New Haven, CT, and Editor in Chief of The Journal of Clinical Hypertension. Panelists included Dr Thomas Giles, Professor of Medicine at Louisiana State University, New Orleans, LA; Dr Joseph Izzo, Jr, Professor of Medicine at SUNY Buffalo School of Medicine, Buffalo, NY; and Dr Henry Black, Roberts Professor of Preventive Medicine at the Rush University School of Medicine in Chicago, Chicago, IL.
Unusual Balloon Rupture During Direct Stenting with a Taxus™Express2™ Stent in a Venous Graft Complicated by Vessel Rupture: A Device‐Related Fatal Event
Authors: CHRISTIANSEN EVALD H.
Published: February 2007

A 70‐year‐old male with a prior coronary artery bypass operation presented with increasing episodes of chest pain. Coronary angiography revealed severe disease of the left anterior descending artery (LAD), CX, and RCA. A left internal mammary artery to LAD was patent. A jump venous graft, with four distal anastomoses, had two significant stenoses. Percutaneous coronary intervention with distal protection, and direct stenting with a drug‐eluting stent, was planned. A 3.00 × 16 mm Taxus™Express2™ (Boston Scientific) was used. At an inflation pressure of 10 atm the stent balloon seemed to extend 20 mm proximally with a diameter of 4.5 mm, and the balloon ruptured. Angiography showed rupture of the vessel proximal to the implanted stent, and the patient developed severe hypotension. The rupture was treated with a covered stent and pericardiocentesis was performed with evacuation of 600 mL blood. However, it was not possible to resuscitate the patient, who died due to severe pump failure and incessant ventricular fibrillation.
Asymmetric information in cattle auctions: the problem of revaccinations
Authors: Chymis Athanasios G. , James Harvey S. , Konduru Srinivasa , Pierce Vern L. , Larson Robert L.
Published: February 2007

We analyze the problem of asymmetric information between buyers and sellers in cattle auctions, using the problem of revaccinations as the point of departure. We present a simple model to show that if buyers do not know and cannot verify whether sellers have vaccinated their animals, then they may consider revaccination. Revaccination is only a part of the broader problem of information asymmetry that includes other quality issues and costs that can be saved, thereby affecting the welfare of both buyers and sellers. We consider structural characteristics of ranching, traditions, and consumers' preferences as well as proposals regarding third‐party certification to argue that the problem of asymmetric information in cattle auctions is a persistent one. We also argue for a comprehensive empirical study of the incidence and impacts of buyer revaccination.