bluuebunny/crossref_metadata_2025_split huggingface dataset:
Daily mood states and ambulatory blood pressure
Authors: SHAPIRO DAVID , JAMNER LARRY D. , GOLDSTEIN IRIS B. 
Published: February 2007

AbstractIn this study, we examined relationships between moods and both ambulatory blood pressure and heart rate in 197 men and women college students. Participants who reported frequently feeling angry during the day had higher levels of blood pressure, especially diastolic pressure during sleep. Reports of sad feelings were positively correlated and reports of pleasant or happy were negatively correlated with diastolic pressure during sleep. Participants scoring high on hostility and anxiety trait measures and low on defensiveness reported negative moods more frequently. Cluster analysis identified different mood profiles. Participants characterized by reports of all negative moods plus anger had high scores on trait hostility and consistently higher levels of blood pressure, particularly diastolic pressure during sleep. Heart rate was not related to mood reports. Hostile and anxious behavioral dispositions may play a role in sleep disturbance and high levels of blood pressure. Positive moods may counter these effects.
Fear‐potentiated startle conditioning in humans: Explicit and contextual cue conditioning following paired versus unpaired training
Authors: GRILLON CHRISTIAN , DAVIS MICHAEL 
Published: February 2007

AbstractConditioned fear in response to explicit and contextual cues was examined using the startle reflex in three groups of participants over two sessions separated by 4–5 days. The conditioned stimulus (CS) was paired with an aversive unconditioned stimulus (US) (shock) during conditioning in the paired but not in the unpaired group. In the reaction time (RT) group, the US was a nonaversive visual signal for an RT task. In the paired group, the CS potentiated startle in the postconditioning phase. This conditioned response was fully retained over the retention interval. There was no substantial change in baseline startle (startle delivered in the absence of CS). By contrast, startle was not potentiated by the CS in the unpaired group, but baseline startle was increased from Session 1 to Session 2. In the RT group, startle was not affected by the CS, and baseline startle was reduced from Session 1 to Session 2. These results suggest that paired presentations of a CS and an aversive US result in conditioned fear in response to the CS but little contextual fear, whereas unpaired presentations of a CS and US leads to poor explicit cue conditioning but substantial contextual fear.
Cardiovascular and neuroendocrine adjustment to public speaking and mental arithmetic stressors
Authors: AL'ABSI MUSTAFA , BONGARD STEPHAN , BUCHANAN TONY , PINCOMB GWENDOLYN A. , LICINIO JULIO , LOVALLO WILLIAM R. 
Published: February 2007

AbstractIn this study, we evaluated cardiovascular. neuroendocrine, and psychological adjustment to repeated presentations of a public speaking and a mental arithmetic task. Brief versions of mental arithmetic tasks have been used widely in previous reactivity studies, and growing attention to more socially salient tasks has led to the increased use of public speaking tasks. However, psychophysiological adjustment during extended and repeated exposure to these tasks has not been delineated. In the present study, 52 healthy men worked on three 8‐min presentations of public speaking and of mental arithmetic in a repeated measure design. Both tasks produced substantial cardiovascular, adrenocorticotropic hormone, and cortisol responses; public speaking produced greater changes. Repeated presentations of public speaking produced a stable pattern of cardiac activation, whereas repetitions of the mental arithmetic initially produced large cardiac responses that changed to a more vascular tonus across task periods. Both tasks increased negative moods. However, correlations between the endocrine, cardiovascular, and negative moods were significant only during the public speaking stressor. The public speaking task is a socially relevant experimental protocol for studying reactivity in the laboratory setting and elicits relatively high, stable, and homogeneous responses.
Temporal stability of lipid responses to acute psychological stress in middle‐aged men
Authors: STONEY CATHERINE M. , NIAURA RAYMOND , BAUSSERMAN LINDA 
Published: February 2007

AbstractThe purpose of this study was to establish the temporal stability of lipid responses to acute psychological stress. Eighteen men were tested twice an average of 16.2 months apart in identical laboratory reactivity protocols. Total cholesterol, triglycerides, high‐ and low‐density lipoprotein‐cholesterol, plasma volume, heart rate, and blood pressure were assessed during rest, serial subtraction, and speech. After correction for changes in plasma volume, significant elevations were recorded for all variables during the speech task, but fewer variables showed changes during the serial subtraction task. Strong intersession associations were found when considering levels of the variables during baseline and stress (rs≥58). Correlations for the change scores ranged from .36 to .52 for the atherogenic lipids and from .39 to .87 for the cardiovascular variables. Little evidence was found for stability of plasma volume changes. There is moderate to high temporal stability of the atherogenic lipids when considering rest and stress levels and small to moderate temporal stability when considering change scores.
Heritability of respiratory sinus arrhythmia: Dependency on task and respiration rate
Authors: SNIEDER HAROLD , BOOMSMA DORRET I. , VAN DOORNEN LORENZ J. P. , DE GEUS ECO J. C. 
Published: February 2007

AbstractIn this study, we investigated the genetic and environmental origin of individual differences in respiratory sinus arrhythmia (RSA) during rest and during four stress tasks. We used a multivariate model including age, RSA, and respiration rate. Participants were 208 male and female pairs of middle‐aged twins. A model without sex differences, specifying additive genetic and unique environmental factors, showed the best fit across all conditions. Heritability of RSA ranged from 28% to 43%. Correction for respiration rate yielded RSA heritabilities of similar size. The covariance between respiration rate and RSA was best explained by a combination of correlated unique environmental and correlated additive genetic factors. Combined with data from an earlier project. RSA from 317 adolescent and 712 middle‐aged individuals of both sexes was available. This large data set showed that (a) sex differences in mean RSA are absent and (b) RSA decreases considerably from adolescence (111.5 ms) to middle age (60.0 ms).
Hemodynamic responses to laboratory stressors in children and adolescents: The influences of age, race, and gender
Authors: ALLEN MICHAEL T. , MATTHEWS KAREN A. 
Published: February 2007

AbstractThe objectives of the present study were threefold: (a) to compare the patterns of hemodynamic responding of children and adolescents during behavioral challenges, (b) to examine whether previously reported cardiovascular reactivity differences between Black and White children are dependent on pubertal status, and (c) to assess whether gender differences in hemodynamic response reported for adults is similar in children. One hundred fifty‐nine children (ages 8–10 years) and adolescents (ages 15–17 years), equally divided along gender and racial lines, participated in a laboratory protocol consisting of a reaction time task, a mirror tracing task, a cold forehead challenge, and a stress interview. Results indicated that adolescents responded with greater β‐adrenergic activation than did children and that gender differences in reactivity often reported for adults emerged more clearly in the adolescents than in the children. This study failed to replicate prior findings of greater vasoconstrictive responses in Black children as compared with White children.
Frequency domain discriminant analysis of the electroencephalogram
Authors: LIND JOHN C. , KOLES ZOLTAN J. , FLOR‐HENRY PIERRE , SOONG ANTHONY C. K. 
Published: February 2007

AbstractA frequency domain generalization of the classical quadratic discriminant function was applied to the problem of classifying alpha‐band multichannel electroencephalogram recordings in three task conditions. The data consisted of 41‐channel recordings obtained in eyes closed, verbal, and spatial task conditions. Classifier performance was measured by deriving a decision rule from a training sample of 42 recordings and then applying the obtained rule to a test sample of 46 recordings The proportion of correct classification was 93 in the training sample and 85 in the test sample. The classifier performed better when based on the complete cross‐spectral matrix than when restricted to power spectrum variables Classification based on a subset of 16 leads reduced the overall proportion of correct classification to 79 in the training sample and to 70 in the test sample.
Social determinants of cardiovascular reactivity: Effects of incentive to exert influence and evaluative threat
Authors: SMITH TIMOTHY W. , NEALEY JILL B. , KIRCHER JOHN C. , LIMON JEFF P. 
Published: February 2007

AbstractThe effects on cardiovascular reactivity of incentive to influence the judgements of the experimenter and the threat of social evaluation were examined in a sample of 60 male and 60 female undergraduates. Participants either were guaranteed $5.00 to prepare and deliver a brief speech or were told that the money was contingent on an evaluation by the experimenter. Participants believed that their speech would be rated for either simple clarity or verbal intelligence. The contingent incentive increased systolic blood pressure reactivity by 6.5 mmHg (32%). Evaluative threat increased systolic reactivity by 7.1 mmHg (36%). These interpersonal processes could increase the risk of cardiovascular disease and are likely to affect the degree of cardiovascular reactivity in laboratory studies.
An ERP analysis of implicit structured sequence learning
Authors: BALDWIN KENNETH B. , KUTAS MARTA 
Published: February 2007

AbstractWhen task exposure facilitates performance without producing corresponding changes in verbalizable knowledge, learning is said to be implicit. In Experiment I, event‐related potentials (ERPs) were recorded as individuals practiced an implicit structured sequence learning (ISSL) task wherein only some target events required a response. With practice, the ERPs to targets that obeyed the underlying grammar diverged from those that did not at around 200 ms; grammatical targets appeared to be more positive between 200 and 500 ms because a similar positivity for the ungrammatical targets was delayed. In Experiment 2, the grammar was simplified allowing a direct comparison to be made between an implicit learning group and an explicit group, who were taught the grammar prior to recording. The results of the comparison revealed a remarkable similarity but did implicate at least partially nonidentical neural mechanisms in implicit and explicit strured sequence learning.
School grades and myopia
Authors: Saw Seang‐Mei , Cheng Angela , Fong Allan , Gazzard Gus , Tan Donald T. H. , Morgan Ian 
Published: February 2007

AbstractAim:  To evaluate the association between school performance and myopia in Singapore children.Methods:  Children aged 10–12 years from two schools in the Singapore Cohort study Of the Risk factors for Myopia (SCORM) were included. Results of a Year 4 standard nation‐wide examination were obtained. Cycloplegic autorefraction and A‐scan ultrasound biometry measurements were performed in the schools.Results:  The odds ratio for myopia (defined as right eye spherical equivalent at least −0.5 D) was 2.5 (95% confidence interval 1.4–4.5) for children with average school examination scores in the fourth quartile compared with the first, after adjusting for confounders including reading in books per week and IQ test scores. Similar significant associations were found for English language (p = 0.001) and native language school examination scores (p < 0.001), while the associations with mathematics school examination scores were of borderline significance (p = 0.055).Conclusion:  School grades, a possible indicator of either cumulative engagement in near work activity or intelligence, were positively associated with myopia in Singapore children.
The effect of drought on the root growth of winter wheat and on its water uptake from a deep loam
Authors: Weir A.H. , Barraclough P.B. 
Published: February 2007

Abstract. Avalon winter wheat was grown on deep silty clay loam soil (Hook series) under a fixed shelter at Rothamsted with either full drought or irrigation from the end of March to July, 1982. During this time the irrigated crop used 295 mm of irrigation water plus 45 mm of stored soil water, while the droughted crop extracted 223 mm of water from the soil. The roots penetrated to at least 1.8m and water was extracted from 2 m depth.Even with a fully developed root system the crops could transpire at the full rate of atmospheric demand only when the near‐surface soil was well supplied with water. However, the draughted crop extracted enough water from the loamy sub‐soil to maintain a reduced transpiration flow for a further nine weeks after the near‐surface water was depleted. Thus crop growth was maintained with a loss at final harvest of only 10% in total dry weight and even less in grain yield.A summary of other results confirm that yield losses due to drought have been reported only for light soils, except in the exceptional year of 1976, and that drought is not normally an important factor affecting yields of winter wheat in the UK.
Soil organic matter, effects on soils and crops
Authors: Johnston A.E. 
Published: February 2007

Abstract. Manurial treatments and cropping history have remained unchanged for many years in classical and long‐term experiments at Rothamsted and Woburn, in some cases for more than 100 years. Soil samples taken periodically have been analysed to follow changes in organic carbon content with time and treatment. Data presented here clearly show effects of carbon input and soil texture on equilibrium organic matter content.Until recently increasing amounts of soil organic matter had little effect on yields of arable crops especially if fertilizer nitrogen dressings were chosen correctly. However the yield potential of many crops has increased and various agronomic inputs have become available to achieve that potential. Yields of many crops are now larger on soils with extra organic matter both on the sandy loam at Woburn and the silty clay loam at Rothamsted. Some of the effect appears to be related to extra water holding capacity, some to availability of nitrogen in ways which cannot be mimicked by dressings of fertilizer N, and some to improved soil physical properties. Responses to fertilizer N have been larger on soils with more organic matter.
Soil moisture regimes and credibility in the assessment of soil suitability for crops in Tuscany
Authors: Busoni E. , Sanesi G. , Torri D. 
Published: February 2007

Abstract. Results of recent research on moisture regimes of surface water soils and on soil credibility are summarized, and proposals are made for the use of results in soil evaluation for selected crops.Measurements of water table depth show high variability from year to year and during the same season. Soil moisture regimes seem to affect soil management more than crop yield. A probabilistic calendar is needed for the occurrence of topsoil moisture content near the lower plastic limit in periods corresponding to the most important management practices. This is required in order to assess important soil qualities like workability and trafficability.Soil erosion is greatest when superficial run‐off can create rills. This happens when run‐off shear stresses exceed a threshold proportional to soil shear strength. Consequently, soil shear strength can be used as a measure of soil resistance to erosion. Probabilistic calendars are needed on the occurrence of heavy rainstorms able to create rills when the soil is most at risk.Entries for ratings of workability, trafficability and erosion risk are outlined.
The quality of topsoil
Authors: Bradshaw A.D. 
Published: February 2007

Abstract. The topsoil widely bought and sold for landscaping and similar schemes is intended to cover poor substrates and to provide improved growing conditions for plants. Two extensive surveys have shown that top soils at present being used are of very poor quality and rarely meet this requirement. Many of the substrates that the topsoils cover out‐perform them, or can readily be improved to do so if modern land reclamation techniques are used.From this it follows that there could, and should, be (i) much more discretion in the use of topsoil, (ii) more attention paid to the improvement of existing substrates, (iii) more consideration given to the use of other materials as topsoil substitutes, and (iv) more care taken in the choice of top soil materials where these have to be used.It is suggested that the present British Standard for topsoil is inadequate and that is should be replaced by a three‐tier system in which there would be separate specifications for; (i) high grade topsoil, (ii) lower grade topsoil, (iii) materials which can act as topsoil substitutes. In this way it should be possible to obtain a better and more reliable performance in landscaping schemes and lower costs.
Soil microbial activity in opencast coal mine restorations
Authors: Harris J.A. , Birch P. 
Published: February 2007

Abstract.A number of restored areas, a soil store and undisturbed areas on opencast coal mine sites, all of similar soil type, were sampled. The microbiological activity (dehydrogenase assay), nitrogen mineralization and nitrifying potentials and physico‐chemical characteristics of the soils were determined. Dehydrogenase activities ranged from 140 to 580 μg TPF g‐124 h‐1in undisturbed control soils, whereas the disturbed soils had activities of 10 to 220 μg g‐124 h‐1, with the smallest activities being recorded in the stored and most recently reinstated soil, indicating that disturbance has depressed microbial activity. Nitrogen mineralization potential was significantly affected by disturbance, with a value of 18 to 26 μg inorganic N g‐121 d‐1in the soil store and 38 μg‐121 d‐1in a soil reinstated for six months, although the values were less than this in soils reinstated for up to six years. Nitrifying potential was not significantly less in the stored soils, being within the range of 60 to 135 μg nitrate N formed g‐1soil 21 d‐1, which was similar to that found in the undisturbed control soil.The water‐holding capacity was less in the stored soil than the undisturbed controls, and was significantly less in soil reinstated for 1.5 to 2.5 years, being only 65% of the undisturbed value (0.66 g water g‐1soil). Ammonium content of the soil store was one hundred fold larger in the soil store than in the controls (0.6 to 1.7 μg ammonium N g‐1). The carbon contents in the control soils ranged from 4.5 to 7.2%, whereas the stored and reinstated soils had generally less amounts ranging from 1.6 to 5.8%. There was a significant and positive correlation between water‐holding capacity and nitrifying potential.The implications for long‐term restoration are discussed.
Morphological and hydraulic properties of a silt loam soil in New Zealand as affected by cropping history
Authors: Francis G.S. , Kemp R.A. 
Published: February 2007

Abstract. A rotation trial of four years’ pasture followed by two years’ arable was used to study the effect of cropping on the morphological and hydraulic properties of soil. An adjacent paddock in grass for the past 35 years was included as a permanent pasture reference. Initial infiltration and field saturated hydraulic conductivity (Kfs) were least for cultivated soil and increased with increasing time under pasture. This could be explained by the contrasting porosities of resin‐impregnated blocks of undisturbed soil which had been infiltrated with methylene blue dye. Small Kfs values for cultivated soil resulted mainly from a thin surface crust, although pore discontinuity at the depth of the cultivation pan (130 mm) could also have contributed. Greater Kfs values under short‐term pasture resulted primarily from water flowing through biogenic pores connected to the surface. The greatest Kfs values were in soil that had been under pasture for 35 years (P35). This was attributed to flow through biogenic pores and fissures associated with the strongly‐developed subangular blocky structure. The amount of water that infiltrated the two‐ and four‐year pasture soils (P2 and P4) under ponding was 2.5 and 5 times greater, respectively, than the soil that had been cultivated for two years (C2).As irrigation duration cannot be varied under the border‐dyking system used on the Canterbury Plains, the interval between irrigations must be varied if the same total amount of water is to be applied to each of these soils through the season. The interval should be less for the cultivated soil than for those under pasture, and should increase with increasing time under pasture (i.e. P35 > P4 > P2 > C2).
How geostatistics can help you
Authors: Oliver M. A. , Webster R. 
Published: February 2007

Abstract. Geostatistics is basically a technology for estimating the local values of properties that vary in space from sample data. Research and development in the last 15 years has shown it to be eminently suited for soil and ripe for application in soil survey and land management. The basic technique, ordinary kriging, provides unbiased estimates with minimum and known variance. Data for related variables can be incorporated to improve estimates using cokriging. By more elaborate analysis using disjunctive kriging the probabilities of deficiency and excess can be estimated to aid decision.The variogram is crucial in all geostatistics; it must be estimated reliably from sufficient data at a sensible scale and modelled properly. Once obtained it can be used not only in the estimation itself but also to choose additional sampling sites, improve a monitoring network or design an optimal sampling scheme for a survey. It may also be used to control a multivariate classification so that the resulting classes are not too fragmented spatially to manage.
The effects of straw disposal and depth of cultivation on the growth, nutrient uptake and yield of winter wheat on a clay and a silt soil
Authors: Christian D. G. , Bacon E. T. G. 
Published: February 2007

Abstract. Experiments were conducted for one year on two different soil types. On a clay soil straw was either (a) burnt, (b) baled leaving the stubble, or (c) chopped and spread. The soil was tine cultivated to depths of 5, 10 or 15 cm or ploughed to 20 or 30 cm before winter wheat was sown conventionally. In addition, a direct‐drilled crop was sown after each straw treatment. On a silt loam soil the direct‐drilled, tine cultivated to 15 cm and ploughed to 30 cm treatments following burning or chopping and spreading straw were repeated.Tine cultivation incorporated less straw than ploughing, decreased plant establishment and early growth but did not decrease yield. Direct‐drilling through chopped straw decreased yield on the silt loam but not on the clay soil. Short straw (< 5 cm) was easier to incorporate than longer straw. Ploughing was the most efficient method of straw incorporation because it inverts soil. Early effects on crop growth and nutrient uptake following straw incorporation were transient and associated with large amounts of straw in the seeded layer of soil.