bluuebunny/crossref_metadata_2025 huggingface dataset:
Pain perception and cardiovascular responses in men with positive parental history for hypertension
Authors: AL'ABSI MUSTAFA , BUCHANAN TONY , LOVALLO WILLIAM R.
Published: February 2007

Evidence suggests a reduced pain sensitivity in hypertensive individuals. This study sought to extend this work to normotensive individuals with hypertensive parents. Men with a positive (PH+) or negative (PH−) parental history for hypertension rated their pain every 15 s during a 90‐s hand cold pressor test and for 90 s after the cold pressor test. Systolic (SBP) and diastolic (DBP) blood pressures and heart rate were measured throughout. After the cold pressor test, the men recalled their pain using the McGill Pain Questionnaire. PH+ men showed greater SBP and DBP responses to the cold pressor test. Although pain ratings during the cold pressor test did not differ between groups, posttest reported pain receded faster in the PH+ than in the PH− men. The PH+ men also reported less total pain on the McGill. These findings support the hypothesis that risk for hypertension may be associated with attenuated pain responses to nociceptive stimuli.
Autonomic, electroencephalographic, and myogenic activity accompanying startle and its habituation during mid‐childhood
Authors: ORNITZ EDWARD M. , RUSSELL ANDREW T. , YUAN HARRY , LIU MINZHI
Published: February 2007

This study investigated (a) possible associations of the large individual variation in startle, with accompanying autonomic, central nervous system, and myogenic activities in a habituation paradigm; and (b) the patterns of habituation of these variables. Startle blinks to 40 noise bursts, heart rate, alpha activity, and orbicularis oculi electromyographic (EMG) activity preceding and following each startle response were measured in 40 normal 7–11‐year‐old boys. Statle amplitude and its habituation were independent of association with either initial values or successive changes in the autonomic, alpha, and EMG activities; whereas startle habituated, pre‐and poststartle myogenic, alpha, and cardiac activities failed to habituate. Tonic cardiac activity was facilitated, suggesting sensitization of state, as proposed in the dual‐process theory of habituation.
Genetic analysis of the resting electroencephalographic power spectrum in human twins
Authors: CHRISTIAN J. C. , MORZORATI S. , NORTON J. A. , WILLIAMS C. J. , O'CONNOR S. , LI T.‐K.
Published: February 2007

Most twin studies have provided evidence for genetic effects on the electroencephalogram (EEG). In two twin studies, monozygotic (MZ) cotwin covariance for EEG power was greater than expected for additive gene actions, as compared with dizygotic (DZ) cotwin covariance. These findings were attributed to complex gene interactions, termed emergenesis. In the present study of 53 MZ and 38 DZ twin pairs departures from the additive genetic model were tested on resting EEG power. Total spectral power and the quotient of (beta band power)/(total power) both fit gene interaction models significantly better than did additive genetic models. These findings support the previous findings of MZ covariance for EEG power as much greater than DZ covariance; these findings can be explained entirely by the additive effects of genes. This pattern of twin covariances could be due to gene interactions but also to greater MZ than DZ environmental covariance.
Theta synchronization and alpha desynchronization in a memory task
Authors: KLIMESCH W. , DOPPELMAYR M. , SCHIMKE H. , RIPPER B.
Published: February 2007

In the present study, we examined the hypothesis that episodic encoding and retrieval processes are primarily reflected by a task‐related increase in theta power. Individuals performed a recognition task with a total of 192 words. The electroencephalogram was recorded during the study and recognition phase. The results show that only those words that were later correctly recognized produced a significant increase in theta power during encoding. During the actual recognition processes too, a significant theta synchronization (increase in band power) was found for correctly remembered words only. In contrast to the theta band, remembered and not remembered words revealed a complex pattern of desynchronization in the lower and upper alpha band that was different during encoding and recognition.
Effects of different sleep duration on delta sleep in recovery nights
Authors: LUCIDI FABIO , DEVOTO ALESSANDRA , VIOLANI CRISTIANO , MASTRACCI PAOLA , BERTINI MARIO
Published: February 2007

The study assessed the effects of different amounts of sleep restriction on slow wave sleep (SWS) in the ensuing recovery nights. After one adaptation night and an 8‐hr baseline night, six healthy men were individually studied during and following five nights in which sleep was reduced to 5, 4, 3, 2, and 1 hr with a 1‐week interval between conditions. Bach sleep reduction was followed by an 8‐hr recovery night. Finally, a second 8‐hr baseline night was recorded. A trend analysis revealed that SWS amount in recovery nights increases with decreasing previous sleep duration. Regression analyses showed that, within each participant, the rebound of SWS after a sleep reduction is predicted better by the total duration of sleep than by the specific amount of SWS lost.
Development and topography of auditory event‐related potentials (ERPs): Mismatch and processing negativity in individuals 8–22 years of age
Authors: OADES ROBERT.D. , DMITTMANN‐BALCAR ALHXANDRA , ZERBIN DIETER
Published: February 2007

How do event related potentials (ERPs) reflecting auditory processing develop across adolescence? Such development was described for five ERP components in four groups of 11 healthy participants with mean ages of 10, 14, 17, and 21 years. Data from 19 sites during diffuse (passive) and focused (discrimination) attention in a three‐tone oddball were analyzed to see how ERP loci varied with age for tone type attention condition, and for four types of difference waves reflecting nontarget and target comparison. Age interacted with site for most components. P1 loci sensitive to rare tones moved postoriorly and N1 loci lost their right bias in early puberty. The P2 loci did not move anterior to Council adulthood N2 amplitude, sensative to attention condition, developed a frontal focus by 17 years. Right biased P3 loci moved lo the midline with focused attention similarly in all age groups. Difference waves developed in three stages; In 10‐years‐old participants early deflection (<150 ms) were diffusely distributed; in mid adolescent participants, the main frontal negative component (150‐300 ms) became well formed and lost an earlier right bias: and for participants 17 years old and older, the late positive complex developed a right bias in target‐derived waves. Latency decreases for early frontal components were marked in participants 10–14 years old and for later posterior components m participants 14–17 years old. Major developments appeared at the onset of adolescence in early stimulus selection processes and during adolescence in the in the differential use of this information (N2‐ and P3‐like latencies).
Sensitivity to mechanical stimuli and the role of general sensory and perceptual processes in heartbeat detection
Authors: KNAPP KELLEY , RING CHRISTOPHER , BRENER JASPER
Published: February 2007

Sensitivity to heartbeat sensations is commonly assessed using tasks that require individuals to judge the simultaneity of heartbeats and tones. In two experiments, we investigated the suitability of this paradigm for examining cardioception. In the first experiment, participants judged the simultaneity of near–threshold vibrations and suprathreshold tones. Precision in judging vibration–tone simultaneity was directly related to the detectability of the mechanical stimuli, thereby supporting use of the simultaneity paradigm to assess heartbeat detection. In the second experiment, we examined the influences of sensitivity to mechanical stimuli and the ability to make intermodality simultaneity judgments on the precision of heartbeat detection. We measured participants' vibrotactile thresholds, precision in judging light–tone simultaneity, and precision in judging heartbeat–tone simultaneity. The ability to judge the simultaneity of lights and tones accounted for 24.3% of the variance in precision of heartbeat detection, and mechanical sensitivity accounted for a further 8.5%.
Different cortical activation patterns in blind and sighted humans during encoding and transformation of haptic images
Authors: RÖDER BRIGITTE , RÖSLER FRANK , HENNIGHAUSEN ERWIN
Published: February 2007

In this study, we investigated whether the occipital cortex of blind humans is activated during haptic perception and/or transformation of a haptic image. Slow event‐related brain potentials were monitored from 18 electrodes in 12 sighted and 15 congenitally blind participants while they were engaged in a haptic mental rotation task. In both groups, slow negative shifts appeared over (a) the frontal cortex at the beginning of each processing episode, (b) the left‐central to parietal cortex during encoding and maintaining of a haptic image, and (c) the central to parietal cortex during image transformation. A pronounced slow negative potential over the occipital cortex emerged only in the blind individuals and was time‐locked to the processing epochs. Its amplitude increased with the amount of processing load. The slow wave effects observed in the blind individuals could indicate that occipital areas participate in specific, nonvisual functions or they could reflect a coactivation of these areas whenever the activation level of task‐specific processing modules located elsewhere in the cortex is raised by nonspecific thalamocortical input.
REM sleep eye movement counts correlate with visual imagery in dreaming: A pilot study
Authors: HONG CHARLES CHONG‐HWA , POTKIN STEVEN G. , ANTROBUS JOHN S. , DOW BRUCE M. , CALLAGHAN GLENN M. , GILLIN J. CHRISTIAN
Published: February 2007

Based on the findings of our previously published positron emission tomography study, we proposed that recorded eye movements during REM sleep are visually targeted saccades. In the present study, we examined the correlation between the number of eye movements in REM sleep (EM) and visual imagery in dreaming (V) and provided further support for our proposal. All the observations (N= 11) were made with one individual to eliminate interindividual variation and were made during the second REM sleep period to control for a time‐of‐night effect. V, with or without dream report length partialled out, was strongly associated with EM only in the 1‐min interval immediately preceding awakening. The time course of the association suggests that the strong EM–V association reflects a phasic, localized activation of the eye‐movement‐control system in association with REM sleep eye movements.
Affective modulation of tactile startle
Authors: HAWK LARRY W. , COOK EDWIN W.
Published: February 2007

Two studies were conducted to investigate affective modulation of startle responses to unilateral tactile probes and to determine whether such modulation is lateralized. Right‐handed undergraduates received airpuffs to the left or right temple while viewing pleasant, neutral, and unpleasant pictures. Side of probe presentation was varied between the two trial blocks of the experiment in Study 1 (n= 48) but varied randomly within trial blocks in Study 2 (n= 48). Primary results were consistent across studies. Replicating and extending the findings for acoustic probes, eyeblink responses to tactile probes were larger during unpleasant than during pleasant pictures. However, affective modulation of startle did not differ reliably between the two sides of probe presentation (sensory laterality) or the two sides of the response (motor lateralily) in either study or in a combined analysis.
Bracken encroachment rates in Britain
Authors: Taylor J. A.
Published: February 2007

Abstract.The bracken fern (Pteridium aquilinum(L.) Kuhn) is emerging as the most successful of international weeds. Tolerant, yet aggressive and opportunist, it follows characteristically in the wake of evacuated settlement, deforestation or reduced biotic pressures. It is hostile to many other plants and to animals, and generates toxins including some carcinogens. It appears to be extending its range into wet and exposed habitats and at its climatic limits. Estimated encroachment rates in the UK average 1%, sometimes 3% per annum, which appears to be unprecedented. Its historical use as an occasional resource, e.g. for litter, bedding, roofing, etc, has mostly ceased. It is now a major source of land loss and land pollution. More work is needed (and is pending) to calibrate bracken spread more precisely, e.g. from satellite imagery. The reclamation of bracken‐infested land is probably more cost‐beneficial per hectare than the reclamation of wetland or heathland, taking any time‐scale.
Assessment of soil erosion risk in England and Wales
Authors: Morgan R.P.C.
Published: February 2007

Abstract. Information on rainfall erosivity, soil erodibility and land capability is combined to produce a map of England and Wales showing areas with a risk of soil erosion at rates above the soil loss tolerance level. About 20 500 km2 or 37% of the arable area is at risk. Given the shallow soils and current rates of erosion, sustained use of this area for cereal, sugar beet and vegetable production beyond the first quarter of the next century is threatened. A further 4000 km2 is at risk in non‐arable areas, mainly associated with blanket peat in the uplands and with coastal sand dunes.
Plant uptake of radionuclides
Authors: Bell J.N.B. , Minski M.J. , Grogan H.A.
Published: February 2007

Abstract. The factors influencing uptake of radionuclides from soils into vegetation are discussed with reference to soil type, radionuclide, plant species and organ, and time since initial contamination. Gaps in knowledge are identified, particularly as highlighted by the unexpected behaviour of radiocaesium in many upland areas of Britain, following deposition after the Chernobyl accident. The importance of resuspended soil for contamination of aerial plant parts is also considered in relation to radionuclide type, vegetation height, and meteorological conditions.

The development of an international database by the International Union of Radioecologists for soil to crop transfer factors of radionuclides derived from European experiments is briefly described. This database is now being used for statistical analyses aimed at quantifying the importance of environmental and biological factors in influencing uptake of radionuclides from the soil.
The disposal of leather tannery wastes by land treatment—a review
Authors: Hughes J.C.
Published: February 2007

Abstract. People in rural areas have disposed of their wastes on land for centuries, relying on the soil's ability to degrade and render harmless any toxic elements the wastes may contain. Leather tanneries produce a large amount of sludge and liquid wastes. The liquids contain much sodium and in most circumstances adversely affect both the soil and groundwater. However, in some countries they are used for irrigation. The sludges contain nitrogen, calcium, magnesium, phosphorus, trivalent chromium and some sodium. Given careful management these sludges can be used as soil amendments, either directly or after composting. Application rates of about 200 tonnes ha−1 have proved toxic to crops in pot trials, though larger applications than this have not adversely affected crops in the field. Much smaller rates, of less than 20 tonnes ha−1, have been used in the field to minimize nitrate contamination of groundwater. The effects of CrIII depend on complex interactions between the sludge, the soil to which it is added and the plant species grown. Safe limits for the disposal of the sludges and their long term effects are not known.
Matching spatial databases and quantitative models in land resource assessment
Authors: Burrough P.A.
Published: February 2007

Abstract. Good land management needs information about land resources and the processes taking place in the landscape. In practical land evaluation this information is often expressed in terms of land qualities. The original survey data are stored in geographical information systems where they can be used to estimate the values of appropriate land qualities. Land qualities are complex attributes of land used in planning that may be derived from the original attributes through empirical threshold or regression models, or from process‐based deterministic or stochastic simulation models. In order to improve estimates of the distribution of land qualities in space and time, and hence to improve planning decisions, the models require data with a much better spatial resolution than is usually available. The problems and dangers associated with the ad hoc linkage of simulation models and GIS are discussed. Particular attention needs to be paid to the problems of error propagation and costs and benefits when using models.
WOFOST: a simulation model of crop production
Authors: van Diepen C.A. , Wolf J. , van Keulen H. , Rappoldt C.
Published: February 2007

Abstract. The WOFOST simulation model is a tool for analysing the growth and production of field crops under a wide range of weather and soil conditions. Such an analysis is important first to assess to what extent crop production is limited by the factors of light, moisture and macro‐nutrients, and second to estimate what improvements are possible. The theoretical concept of a production situation, as modelled by WOFOST, is explained, as is the hierarchy of potential production and water‐limited and nutrient‐limited production situations in the analysis. The organization of the computer files in the model, the structure of the FORTRAN source program and the available standard sets of data are described briefly.
Afforestation and sediment yields in British fresh waters
Authors: Soutar R.G.
Published: February 2007

Abstract. This paper reviews research on sediment yields in British fresh waters affected by afforestation in their catchments. Soil erosion and sedimentation in fresh waters increase after afforestation in the uplands. In the long term a three‐to tour‐fold increase appears to be common in established upland forests, but much larger increases, some amounting to 50 times that before afforestation, have been recorded soon after ploughing, draining, roadmaking and harvesting. Some of the erosion has been exacerbated by environmental conditions such as steep slopes and storms. Improved silvicultural practices should reduce sediment output to fresh waters, but they might not prevent serious sedimentation following afforestation in the uplands. In contrast, afforestation of arable land under the Farm Woodland Scheme should result in decreased rates of erosion in the lowlands.
Employing elevation data for efficient mapping of soil pollution on floodplains
Authors: Leenaers H. , Okx J.P. , Burrough P.A.
Published: February 2007

Abstract The co‐regionalization between relative elevation and zinc concentration was used to map zinc concentration in the soil of the Geul floodplain in the southern Netherlands by co‐kriging from 154 observations. Point co‐kriging and point kriging for estimating zinc content in the soil were compared in terms of kriging variances. Another 45 samples were used to compare the precision of the estimated values in terms of squared and absolute estimation errors. Point co‐kriging produced better estimates of zinc concentration than either simple point kriging or linear regression from the relative elevation data alone. Moreover, the estimation variances for co‐kriging are substantially smaller than those for kriging. The results suggest that knowledge of geomorphological processes can often improve the quality of interpolation maps of properties that are expensive to measure.
Tillage and mulching effects on seed‐zone soil environment and cowpea seedling growth in the humid tropics
Authors: Osuji G.E.
Published: February 2007

Abstract. Tillage and mulching effects on the environment of the seed zone and on growth of cowpea (Vigna unguiculata) seedlings in the humid tropics were studied at Ibadan, southwestern Nigeria, in the 1987 and 1988 late cropping seasons. The split‐plot design experiment had conventional tillage (ploughing and harrowing), reduced tillage (ploughing only), zero tillage and grass mulch treatments. Conventional and reduced tillage practices decreased initial bulk density and increased seedling emergence, root growth, dry matter yield and overall seedling performance. Addition of mulch increased the soil moisture in the root zone and significantly decreased maximum soil temperatures and diurnal fluctuations in temperature. This provided a more stable environment for seedling establishment and growth than the unmulched soil.
Leaching of spring—applied fertilizer nitrogen: measurement and simulation
Authors: Lord E.I. , Bland G.
Published: February 2007

Abstract. The leaching of spring‐applied fertilizer nitrogen was measured by soil sampling on three soils widely used for spring cropping: a loamy sand, a sandy loam and a sandy silt loam. Soils were fallow during the experiment. Results were compared with simulations obtained with a computer leaching model. The model differentiated well between soil types, and predicted mineral nitrogen remaining in the top 30, 60 or 90 cm with reasonable precision. It tended to over‐estimate the rate of nitrification of ammonium from ammonium nitrate fertilizers. The causes of occasional large discrepancies between sampling and measurement are discussed.
Effect of trampling on the soils of the St James Walkway, New Zealand
Authors: Stewart D. P. C. , Cameron K. C.
Published: February 2007

Abstract. The influence of trampling on the soils of the St James Walkway was studied during 1985 by comparing ‘on’‐ and off‐track sites. Trampling increased the average soil bulk density by 0.3 g/cm3 at 0–5 cm depth and by 0.1 g/cm3 at 10–15 cm depth. Trampling increased the average soil shear strength by 11 kPa at 0–5 cm depth and by 6 kPa at 5–10 cm depth. All mineral soils were compacted to some extent by trampling. The podzolized high country yellow‐brown earths (Dystrochrepts) were the most affected because their organic topsoil was truncated. Their exposed subsoil was however more resistant to further damage than their topsoil. Organic soils (Medihemists) were not compacted but their very low shear strength and high moisture content make them unsuitable for tracks. Untrampled soil bulk density and soil stone content were negatively correlated with the change in bulk density by trampling, and could be used to predict the risk of soil compaction by trampling.
Seasonal variation of pyrite oxidation rates in colliery spoil
Authors: Backes C. A. , Pulford I. D. , Duncan H. J.
Published: February 2007

Abstract. Oxidation rates of pyrite in colliery spoil were measured under both field and laboratory conditions. Meld oxidation rates varied through the year, depending primarily upon temperature. Rates of acid release of 7–15 μmoles H+/day were measured in field lysimeters in the period May to November. Little oxidation of the pyrite occurred between November and May; the rates in the summer months were approximately 5–10 times those during die winter. The rate of oxidation in the summer was limited by the solubility of amorphous iron oxides. Slow oxidation during the winter is probably related to the inactivity of Thiobacillus ferrooxidans at low temperatures. The rates of acid production in the laboratory in the temperature range 0–18°C were similar to those in the field. Materials inhibiting pyrite oxidation should be added when oxidation rates are slow, so that they are not overwhelmed by large amounts of acid.
Nitrogen transformations in a peaty soil improved for pastoral agriculture
Authors: Isabella B.L. , Hopkins D.W.
Published: February 2007

Abstract.Microbial transformations and chemical distribution of N were compared in two upland stagnohumic gley soils at the same site. In 1981 one soil was improved for more intensive agriculture by lime and fertilizer applications and reseeding with a grass/clover mixture. The other soil (referred to here as unimproved) was also reseeded in 1981, but no lime was added and the sward has subsequently reverted to rough grazing land. Improvement resulted in greater soil microbial activity. The improved soil showed greater rates of denitrification, net N immobilization and N fixation (acetylene reduction) and contained more microbial biomass N than the unimproved soil. However, no major differences in the distribution of organic N fractions were detected. This indicates that a large amount of the soil N present before improvement did not undergo mineralization and remained unavailable to plants.
Runoff and leaching of alachlor under conventional and soil‐specific management
Authors: Khakural B.R. , Robert P.C. , Koskinen W.C.
Published: February 2007

Abstract. The influence of conventional and soil‐specific management on leaching and runoff losses of soil‐applied alachlor (2‐chloro‐2′,6′‐diethyl‐N‐(methoxymethyl) acetanilide) was studied across a soil catena (landscape) with varied slope and drainage characteristics. The catena consisted of: a well‐drained Ves (fine‐loamy, mixed, mesic Udic Haplustoll) soil on the backslope (1–4%), a Ves soil on the sideslope (6–12%), and a poorly drained Webster (fine‐loamy, mixed, mesic Typic Haplaquoll) soil on the toeslope (0–3%). In general, the concentration of alachlor in runoff water was greater in the Ves soil than in the Webster. In 1992 alachlor concentrations in runoff (water, sediment + water) were less for soil‐specific rates (2.20 or 2.80 kg/ha) than for a uniform rate (3.36 kg/ha) in both Ves soils. There was no significant difference in alachlor concentration related to application rates (soil‐specific rate 3.66 kg/ha) in the runoff from the Webster soil. Averaged across soils and events, the concentrations of alachlor in runoff (water, sediments + water) were less for soil‐specific rates than for the uniform rate. Alachlor was not detected in soil samples obtained from depths greater than 15 cm in any soil or treatment after the first sampling. At the first sampling in 1992 (7 days after application) alachlor was detected down to 45 and 90 cm in the Ves and Webster soils, respectively. Detectable amounts (≥0.1 μg/1) of alachlor were observed in soil water samples extracted from all three soils during some sampling dates. No particular trends were observed with soils or application rates.
Nitrogen and phosphorus transformations as affected by crop residue management practices and their influence on crop yield
Authors: Beri V. , Sidhu B.S. , Bahl G.S. , Bhat A.K.
Published: February 2007

Abstract.A 15‐year field experiment investigated crop residue management practices, with crop residue removal, burning and incorporation as the main treatments and nitrogen levels as subtreatments. The effects of crop residue management practices on rice and wheat yield were measured for 11 years. Surface soil samples were taken to study nitrogen and phosphorus immobilization/adsorption and their release under laboratory conditions. The field experiment indicated that residue burning and residue removal resulted in greater grain yields of rice (5.57 and 5.53 t/ha, respectively) and wheat (4.12 and 4.02 t/ha, respectively) than residue incorporation (4.51 t/ha rice and 3.72 t/ha wheat). Laboratory experiments indicated that by the addition of crop residues nitrogen and phosphorus were converted to unavailable forms through immobilization and adsorption, respectively.

Crop residue management practices were discontinued after 13 years and wheat and maize crops were grown in sequence. There were significantly greater yields of wheat (3.57 t/ha in 1992–93 and 3.6 t/ha in 1993–94) and of maize (2.1 t/ha in 1993) in plots where the residues had previously been incorporated than where the residues were previously either removed or burned. This is attributed to release of nitrogen and phosphorus from the incorporated residues.
Field assessment of crusting on a tilled sandy clay loam
Authors: Mellis D.A. , Bruneau P.M.C. , Twomlow S.J. , Morgan R.P.C.
Published: February 2007

Nine different techniques were used to record the initial change in the physical and hydrological properties of a freshly tilled soil surface following successive cycles of wetting and drying. The study was made in the field on a sandy clay loam soil ploughed and harrowed and then exposed to three simulated rainfall events of 76 mm/h for 15 minutes. Although the degradation of the soil surface increased with each successive rainfall, the most significant changes were observed after the first rainfall. Qualitative observations of clod size distribution and crust development provide a good indication of the early stages of soil surface degradation. Complementary physical data were quickly obtained using a hand held shear vane. These techniques are simple and robust enough that they can be used in on‐farm research programmes, where resources, both human and technical are at a premium. Tension infiltrometry provided hydrological information that complemented the physical information provided by the above techniques, but is not as simple.
A world dataset of derived soil properties by FAO–UNESCO soil unit for global modelling
Authors: Batjes N. H.
Published: February 2007

A standardized dataset of derived soil properties for the 106 soil units considered on FAO‐UNESCO's 1:5 million scale Soil Map of the World is presented. It was derived from a statistical analysis of the 4353 soil profiles held in the WISE (World Inventory of Soil Emission) database, which was developed at the International Soil Reference and Information Centre (ISRIC) for the geographic quantification of soil factors that control processes of global change. Median values are presented by soil unit for selected soil properties including: pH(H2O); organic carbon content; cation exchange capacity; sum of exchangeable Ca2+, Mg2+ and K+; exchangeable sodium percentage; bulk density; total porosity; available water capacity; soil drainage class; and gravel content class. Medians for these variables are presented both for the topsoil (0–30 cm) and subsoil (30–100 cm), where applicable. The data set can help to refine ratings for soil quality in global environmental models pending the availability of comprehensive georeferenced databases on soil and terrain resources such as SOTER, the World Soil and Terrain Database. In a Geographical Information System (GIS) it can be linked to the units shown on the digital Soil Map of the World through the legend code.
Greenhouse gas emissions from farmed organic soils: a review
Authors: Kasimir‐Klemedtsson Å. , Klemedtsson L. , Berglund K. , Martikainen P. , Silvola J. , Oenema O.
Published: February 2007

Abstract. The large boreal peatland ecosystems sequester carbon and nitrogen from the atmosphere due to a low oxygen pressure in waterlogged peat. Consequently they are sinks for CO2 and strong emitters of CH4. Drainage and cultivation of peatlands allows oxygen to enter the soil, which initiates decomposition of the stored organic material, and in turn CO2 and N2O emissions increase while CH4 emissions decrease. Compared to undrained peat, draining of organic soils for agricultural purposes increases the emissions of greenhouse gases (CO2, CH4, and N2O) by roughly 1t CO2 equivalents/ha per year. Although farmed organic soils in most European countries represent a minor part of the total agricultural area, these soils contribute significantly to national greenhouse gas budgets. Consequently, farmed organic soils are potential targets for policy makers in search of socially acceptable and economically cost‐efficient measures to mitigate climate gas emissions from agriculture. Despite a scarcity of knowledge about greenhouse gas emissions from these soils, this paper addresses the emissions and possible control of the three greenhouse gases by different managements of organic soils. More precise information is needed regarding the present trace gas fluxes from these soils, as well as predictions of future emissions under alternative management regimes, before any definite policies can be devised.
Liming practice in temperate forest ecosystems and the effects on CO2, N2O and CH4 fluxes
Authors: Borken W. , Brumme R.
Published: February 2007

Abstract. The effect of superficial liming of acidic forest soils on CO2 and N2O emissions and CH4 uptake was investigated with closed chambers in two deciduous and two spruce forests, by weekly to biweekly measurements over at least one year. The flux rates of untreated areas varied between 1.94 and 4.38 t CO2‐C/ha per y, 0.28 and 2.15 kg/N2O‐N/ha per y and between 0.15 and 1.06 kg CH4‐C/ha per y. Liming had no clear effect on CO2 emissions which may change in the long‐term with decreasing root turnover and increasing C‐mineralization. Apart from one exception, liming resulted in a reduction of N2O emissions by 9 to 62% and in an increase of CH4 uptake by 26 to 580%. The variability in N2O emissions between the forest sites could not be explained. In contrast, the variability of annual CH4 uptake rates could be explained by N content (r2= 0.82), C content (r2= 0.77), bulk density (r2= 60), pore space (r2= 0.59) and pH (r2= 0.40) of mineral soil at a depth of 0 to 10 cm, and by the quantity of material in the organic layer (r2= 0.66). Experiments with undisturbed columns of the same soils showed that between 1 and 73% of the total N2O emissions came from the organic layer. However, atmospheric CH4 was not oxidized in this layer, which represents a diffusion barrier for atmospheric CH4. When this barrier was removed, CH4 uptake by the mineral soil increased by 25 to 171%. These results suggest that liming of acidic forest soils causes a reduction of the greenhouse gases N2O and CH4 in the atmosphere, due to changes in the chemical, biological, and physical condition of the soils.
Aggregate stabilization in kaolinitic soils by low rates of anionic polyacrylamide
Authors: Miller W. P. , Willis R. L. , Levy G. J.
Published: February 2007

Abstract. The stability of aggregates can be improved by amending the soil with charged synthetic polymers. We have evaluated the effects of addition of low rates of anionic polyacrylamide (PAM) on the stability of aggregates from three predominately kaolinitic soils, and investigated whether the applied PAM penetrated into the aggregates or was adsorbed onto exterior surfaces only. Aggregates (6.3–9.5 mm) from the Ap horizons of a Cecil sandy loam and a Cecil loamy sand (Typic Kanhapludult) and from the Bt horizon of a Davidson clay (Rhodic Kandiudult) were treated with a high molecular weight(2 × 107Da), negatively charged (20% hydrolysis) PAM at rates of 0, 10 or 20 kg/ha. The treated aggregate were dried and exposed to 20 mm of high kinetic energy (23.0 kJ/m3) simulated rain. Some of the PAM‐treated Cecil loamy sand aggregates (5 or 10 kg/ha) were broken in half to expose untreated aggregate interiors to the rain. Percentage stable aggregates (weight/weight) in the PAM treatments ranged from 52 to 97%, vs. 20‐32% in the control. PAM addition significantly increased the percentage of >4 mm sized aggregates compared with the untreated aggregates. PAM was more effective at stabilization in the light to medium textured Cecil soils than in the clayey Davidson. When internal surfaces of PAM treated aggregates were exposed, the percentage of stable aggregates exceeded the amount expected if the polymer was only adsorbed on to external surfaces. This suggested that some PAM had penetrated to some degree into aggregate interiors, thereby stabilizing both external and internal aggregates surfaces. Based on these results it is envisaged that use of PAM could be a viable alternative to the commonly used soil and water conservation practices (e.g. mulching, dyking, contour tillage).
Causal Complexity and Party Preference
Authors: GRENDSTAD GUNNAR
Published: February 2007

Abstract.  Qualitative Comparative Analysis (QCA) overlaps logistic regression in explaining events, but challenges the latter's lack of accounting for causal complexity. QCA has only to a limited degree been applied to large‐N studies or individuals as cases and has not incorporated the logic of probability. QCA and logistic regression are compared with respect to logic, procedure and outcome. Political orientations from five national surveys are adapted to the requirements of the two methods. The methods are demonstrated on explanations of individuals' party preferences. QCA and logistic regression converge and overlap in identifying degrees of causal complexity, in ascertaining model significance and in identifying antecedents to party preference. Results differ in degree, not in kind. A slightly more nuanced picture emerges using the QCA approach, whereas logistic regression delivers greater parsimony. Choice of method(s) is not arbitrary. QCA can easily be used on any large‐N research problem. It should apply probability when appropriate.
Coronary Risk Factors in Adult Children of Parents With Coronary Heart Disease: A Comparison Survey of Southeastern Brazil and Southeastern United States
Authors: Nelia Bueno , Barbara J. Fletcher , Gerald F. Fletcher , Salvador Serra , Di Marco da Cruz Pedro , Deborah Kelly , Luisa Meirelles , Elizabeth Atkinson , Leigh Ann Tabor , Adriana Ramos , Iran Castro
Published: February 2007

A survey was performed in southeastern Brazil and in the southeastern United States to: 1) compare coronary risk factors in adult children (>18 years old) of parents with coronary heart disease enrolled in cardiac rehabilitation programs in countries with different geographic, social, and economic factors; and 2) to assess the influence of coronary heart disease of parents on alteration of lifestyle in these adult children. There were 286 biological children available for the survey (135 Brazil, 151 United States). Of those, 142 completed the survey (78 Brazil, 64 United States) for an overall compliance rate of 50% (58% Brazil, 42% United States). The following differences were noted: blood pressure <159/90 mm Hg (23% Brazil, 15% United States [nonsignificant]); total cholesterol <181 mg/dL (5% Brazil, 30% United States
[p<0.001]); HDL‐C <35 mg/dL (95% Brazil, 21% United States [p<0.001]); low‐fat diet (29% Brazil, 64% United States [p<0.001]); smoke/ever (41% Brazil, 34% United States [nonsignificant]); currently smoke (72% Brazil, 18% United States [p<0.001]); any exercise [44% Brazil, 82% United States [p<0.001]); exercise <90 minute/week (18% Brazil, 20% United States [nonsignificant]); improved lifestyle habits (39% Brazil, 79% United States [p<0.001]); improved lifestyle habits related to parent's coronary heart disease (66% Brazil, 35% United States [p<0.05]). Such differences may reflect geographic, social, and/or economic factors.
Ophthalmoscopic Findings in Malignant Hypertension
Authors: Hammond Stephen , Wells Jill Razor , Marcus Dennis M. , Prisant L. Michael
Published: February 2007

Malignant hypertension may present with retinopathy, choroidopathy, and optic neuropathy. Flame‐shaped retinal hemorrhages, an early finding, are due to smooth muscle necrosis and bleeding along the nerve fiber layer. Cotton‐wool spots, or cytoid bodies, are not exudates, but rather are retinal infarcts. Hypertensive optic neuropathy is a late finding. Optical coherence tomography is a relatively new imaging technique for evaluating retinal thickness and the location of pathology in patients with malignant hypertension.
Angiotensin Receptor Blockers: New Considerations in Their Mechanism of Action
Authors: Sica Domenic A.
Published: February 2007

Angiotensin receptor blockers are one of several drug classes that act by hindering activity of the renin–angiotensin axis. Angiotensin receptor blockers act by selectively blocking the binding of angiotensin II to the angiotensin type 1 receptor but not the angiotensin type 2 receptor. Compounds in this class are as effective as most other antihypertensive drug classes in reducing blood pressure in the patient with hypertension. The mechanism of action of an angiotensin receptor blocker, which seemed a straightforward proposition early on, has of late become more convoluted with a host of class and compound‐specific concerns having emerged. As the mechanistic basis for the action(s) of angiotensin receptor blockers more completely unfolds, added credence may ultimately be lent to widely touted and often overstated intraclass differences.
Hypertension Research in Sleep Apnea
Authors: Hargens Trent A. , Nickols‐Richardson Sharon M. , Gregg John M. , Zedalis Donald , Herbert William G.
Published: February 2007

Obstructive sleep apnea (OSA) is characterized by repetitive partial and total collapse of the upper airway that induces stressful arousals throughout sleep to reestablish breathing. Although estimates vary, prevalence has been reported as high as 20% in the adult population. OSA is common in several chronic diseases, the most common of which is obesity. Evidence is strong that OSA increases the risk of hypertension and both fatal and nonfatal cardiovascular events. Several mechanisms linking OSA to hypertension have been proposed, with increased sympathetic activation implicated as the prime mediator. This review summarizes recent data on the influence of OSA on blood pressure, the effect of standard OSA therapy on improving blood pressure, and the potential of lifestyle modification for further decreasing hypertension risk. Challenges confronting the investigation of blood pressure outcomes in response to treatment in OSA patients are discussed.
Efficacy of a Once‐Daily Formulation of Carvedilol for the Treatment of Hypertension
Authors: Weber Michael A. , Bakris George L. , C Elizabeth A. , Iyengar Malini , Fleck Richard , Sica Domenic A.
Published: February 2007

β‐Blockers with pharmacologic effects that differ from conventional agents might add to antihypertensive treatment options. This study evaluated a new once‐daily formulation of the β‐/α1‐blocker, carvedilol controlled‐release (CR), in hypertensive patients off treatment or while still taking up to 2 (non‐β‐blocker) agents. After a 4‐week run‐in phase, patients were randomized either to placebo (n=76) or carvedilol CR 20 mg (n=82), 40 mg (n=76), or 80 mg (n=86) once daily. After 6 weeks of treatment, ambulatory blood pressure monitoring was repeated to measure the primary end point of changes in mean 24‐hour diastolic blood pressure. During treatment, 24‐hour diastolic blood pressure fell in the placebo and carvedilol CR 20‐mg, 40‐mg, and 80‐mg groups by (mean + SE) 0.4±0.9, 4.4±0.9, 7.9±0.9, and 9.6±0.9 mm Hg, respectively (P≤.001, trend test for all carvedilol CR doses with placebo). Corresponding 24‐hour systolic blood pressure changes were 0.6±1.4, 6.8±1.3, 10.1±1.4, and 12.5±1.3 mm Hg, respectively (P≤.001, trend test). Diastolic blood pressure trough‐to‐peak ratios (placebo‐corrected) based on ambulatory blood pressure monitoring (trough = mean of 20‐ to 24‐hour post‐dose readings; peak = mean of 3‐ to 7‐hour post‐dose readings) for 20‐mg, 40‐mg, and 80‐mg doses were 0.73, 0.64, and 0.65, respectively. Adverse events, including clinical chemistry values, were similar in the drug‐treated and placebo groups. Carvedilol CR has a clinically meaningful defined dose‐dependent antihypertensive effect that persists throughout a 24‐hour period.
Drug Interactions and Drugs That Affect Blood Pressure
Authors: Elliott William J.
Published: February 2007

Many antihypertensive drugs have important interactions with drugs used for different purposes; when these are used concomitantly, adverse effects on blood pressure can result. Fortunately, in recent years, the drug development process has generally discouraged the approval and marketing of antihypertensive drugs with this problem, although some anomalies still exist (eg, telmisartan + digoxin). Physicians who work in emergency departments are more familiar with illicit or unregulated drugs that affect blood pressure; chief among these are cocaine and other opioids, and methylphenidate and its congeners. The most important prescription drugs that affect blood pressure are the nonsteroidal anti‐inflammatory drugs (including selective inhibitors of the second isoform of cyclooxygenase) and steroids. Phenylpropanolamines, some antidepressants, and sibutramine can often be avoided, as they raise blood pressure in a significant proportion of those who take them. Conversely, the hypertensive effects of calcineurin inhibitors and erythropoietin are most commonly overcome by increasing the intensity of antihypertensive drug treatment, since these drugs are essentially unavoidable in most patients who receive them.
Fibromuscular Dysplasia: An Uncommon Cause of Secondary Hypertension
Authors: Prisant L. Michael , Szerlip Harold M. , Mulloy Laura L.
Published: February 2007

Fibromuscular dysplasia is a noninflammatory vascular disease that commonly affects the distal two thirds of the renal artery and branch vessels, but occasionally involves other arteries. Progression of stenosis occurs in 16%–38% of renal arteries. Although the etiology is unknown, genetic studies suggest a relationship to the angiotensin‐converting enzyme I allele. Thin, young Caucasian women without a family history of hypertension are most commonly affected. An abdominal or flank systolic‐diastolic bruit is an important clue for the diagnosis. Most noninvasive screening tests are not sensitive or reproducible to be used to rule out renal artery stenosis, but digital subtraction renal angiography usually confirms the diagnosis. Percutaneous renal artery angioplasty is the treatment of choice, but may not result in normalization of blood pressure if diagnosis is delayed. Since restenosis occurs, continued follow‐up is necessary.
Primary Aldosteronism: Diagnosis and Treatment
Authors: Pimenta Eduardo , Calhoun David A.
Published: February 2007

Recent studies have indicated a higher prevalence of primary aldosteronism (PA) than reported historically. Aldosterone excess induces sodium and fluid retention with consequential increases in blood pressure. Patients with PA are at an increased risk of developing left ventricular hypertrophy, chronic kidney disease, and endothelial dysfunction. Measurement of the plasma aldosterone/plasma renin activity ratio is an effective screening test for PA. The majority of patients with PA do not have a discernable aldosterone‐producing adenoma (APA), and the aldosterone excess is considered idiopathic in etiology and/or attributed to adrenal hyperplasia. Treatment of PA includes medical therapy with mineralocorticoid receptor antagonists and adrenalectomy for patients with a unilateral APA. A reasonable treatment strategy is to attempt medical therapy in all patients with a high plasma aldosterone/PRA ratio and reserve the extensive workup needed to identify an APA for those patients whose hypertension or hypokalemia cannot be controlled medically.