bluuebunny/crossref_metadata_2025 huggingface dataset:
Event‐related brain potentials and error‐related processing: An analysis of incorrect responses to go and no‐go stimuli
Authors: Scheffers Marten K. , Coles Michael G. H. , Bernstein Peter , Gehring William J. , Donchin Emanuel
Published: February 2007

Recent research has suggested that there is a component of the event‐related brain potential, the error‐related negativity (ERN), that is associated with error detection and remedial actions such as error inhibition, immediate error correction, or error compensation. The present experiment used a go/no‐go task to define more precisely the functional significance of this component. In this task, an ERN was observed for incorrect responses on go trials (errors of choice) and for response on no‐go trials (errors of action). Because errors of action cannot be corrected immediately by executing another response, these results indicate that the process manifested by the ERN is not dependent on immediate error correction. Other aspects of the data converge in suggesting that the ERN process is more U related to error detection and that the connections between detection and remedial actions may depend on the task situation.
Heart rate reactivity and heart period variability throughout the first year after heart transplantation
Authors: Shapiro Peter A. , Sloan Richard P. , Bagiella Emilia , Bigger J. Thomas , Gorman Jack M.
Published: February 2007

Heart rate reactivity to mental stress is substantially blunted early after heart transplantation, suggesting that the loss of neural modulation limits the cardiovascular response to mental stress. We tested whether reactivity to mental stress recovers during the first year after heart transplantation. Hemodynamic and respiratory responses to mental arithmetic challenge were studied in 20 heart transplant recipients 3, 6, and 12 months after surgery. A normal comparison group was studied at equivalent intervals. Heart rate reactivity to mental arithmetic was significantly reduced in the cardiac transplant group compared to the normal subjects. This effect persisted up to 1 year after transplantation. Heart period variability in the heart transplant recipients was minimal in all three‐test sessions. The findings suggest that no functional reinnervation or other compensatory adaptation occurs up to 1 year after heart transplantation.
Effect sizes and p values: What should be reported and what should be replicated?
Authors: Greenwald AnthonyG. , Gonzalez Richard , Harris Richard.J. , Guthrie Donald
Published: February 2007

Despite publication of many well‐argued critiques of null hypothesis testing (NHT). behavioral science researchers continue to rely heavily on this set of practices. Although we agree with most critics' catalogs of NHT's flaws, this article also takes the unusual stance of identifying virtues that may explain why NHT continues to he so extensively used. These virtues include providing results in the form of a dichotomous (yes/no) hypothesis evaluation and providing an index (p value) Mini has a justifiable mapping onto confidence in repeatability of a null hypothesis rejection. The most‐criticized flaws of NHT can be avoided when the importance of a hypothesis, rather than the p value of its test, is used to determine that a finding is worthy of report, and when p=.05 is treated as insufficient basis for confidence in the replicability of an isolated non‐null finding. Together with many recent critics of NHT, we also urge reporting of important hypothesis tests in enough descriptive detail to permit secondary uses such as meta‐analysis.
How we think about cognition, emotion, and biology in psychopathology
Authors: MILLER GREGORY A.
Published: February 2007

The variety of potential relationships assumed between psychological and biological concepts fosters considerable misunderstanding of what our data can tell us. A naively reductionistic view of psychological concepts is prevalent, particularly in the psychopathology literature. A series of examples of the application of psychophysiological methods in studies of cognition, emotion; and psychopathology provides a background for a discussion of these problems. Unwarranted distinctions between cognition and emotion, between classes of measures, and between psychological and biological approaches to understanding normal functioning and psychopathology undermine the ability of cognitive neuroscience to achieve its considerable potential. A nondualistic, nonreductionistic, noninteractive relationship is recommended, with psychological and biological concepts both having central, necessary, and distinct roles.
Cortical correlates of semantic classical conditioning
Authors: MONTOYA PEDRO , LARBIG WOLFGANG , PULVERMÜLLER FRIEDEMANN , FLOR HERTA , BIRBAUMER NIELS
Published: February 2007

Event‐related potentials to visually displayed pseudowords were registered from 13 individuals. In a differential conditioning paradigm, half of the pseudowords had previously been paired with a painful electric shock (shock words) and the other half had been presented without shock (nonshock words). Participants were asked to decide if the words had been presented during the conditioning phase or not. Larger N100 amplitudes and a more negativegoing slow wave 400–800 ms after word presentation were found for shock as compared with nonshock words. This effect was stronger over the left than over the right hemisphere. This left‐lateralized negativity might reflect the activation of a cell assembly representing the memory of the learned word‐shock contingency. Furthermore, the increased N100 amplitude elicited by shock as compared with nonshock words may be interpreted as an increased attentive facilitation for aversive pain‐related information as a consequence of conditioning.
Differential involvement of the human temporal lobe structures in short‐ and long‐term memory processes assessed by intracranial ERPs
Authors: GUILLEM FRANÇOIS , N'KAOUA BERNARD , ROUGIER ALAIN , CLAVERIE BERNARD
Published: February 2007

Intracranial event‐related potentials (ERPs) elicited during a recognition memory task were recorded in 25 epileptic patients by using depth electrodes sampling four different regions within the temporal lobe (amygdala, hippocampus, anterior and posterior temporal cortices). The task was a continuous recognition memory task in which repeated items were presented after 6 or 19 intervening items following their first presentation. This study was performed to investigate the respective role of the different temporal lobe structures in short‐term memory (STM) and long‐term memory (LTM) processing. Subregions of the temporal lobe were differently involved in these two memory systems. The posterior temporal cortex is specifically involved in STM processing, whereas the amygdala, hippocampus, and anterior temporal cortex contribute to both STM and LTM. Moreover, it appeared that the latter structures play their own role in LTM. The anterior temporal cortex and amygdala may contribute to recency discrimination, and the hippocampus seems rather to be involved in maintaining memory traces. These findings suggest that the temporal lobe structures may function in a complementary way by subserving different aspects of information processing.
Effects of cigarette smoking on EEG spectral‐band power, dimensional complexity, and nonlinearity during reaction‐time task performance
Authors: HOULIHAN MICHAEL E. , PRITCHARD WALTER S. , KRIEBLE KELLY K. , ROBINSON JOHN H. , DUKE DENNIS W.
Published: February 2007

Electroencephalogram (EEG) and heart rate (HR) were recorded while individuals performed visual and auditory go/no‐go reaction time (RT) tasks. Overnight‐abstaining smokers smoked two types of cigarettes in a single morning session. The first type was smoked once and had a nicotine yield of 0.05 mg. Two cigarettes of the second type (1.1 mg) were smoked. Four recordings were made: presmoking, postsmoking 0.05 mg, and postsmoking each 1.1 mg. HR was increased only by the first 1.1‐mg cigarette. Smoking both the 1.1‐mg cigarettes decreased RT. Smoking the first 1.1‐mg cigarette increased EEG power in the beta2 band. A flexible effect of smoking the first 1.1‐mg cigarette on EEG dimensional complexity (DCx) was obtained at locus Cz. Specifically, DCx was (a) raised when the presmoking level was low, (b) not affected when the presmoking level was intermediate, and (c) lowered when the presmoking level was high. Surrogate‐data testing indicated the presence of nonlinearity in the EEG data that was not affected by smoking. Decreased RT was associated with increased DCx in the visual task only.
Negative difference potential isolates scalp potentials generated by activity in supraspinal nociceptive pathways
Authors: DOWMAN ROBERT
Published: February 2007

A negative difference potential (75–240 ms poststimulus) was computed by subtracting the sural nerve‐evoked somatosensory evoked potential (SEP) elicited at the pain threshold level from SEPs elicited at noxious levels. The effects of stimulus intensity and interstimulus interval on the negative difference potential amplitude plus conduction velocity measurements and a dipole source localization analysis all suggest that the negative difference potential reflects the response of neurons in the primary somatosensory cortex to inputs that arise from the nociceptive A delta peripheral afferents. Furthermore, a comparison of these results with our earlier sural nerve‐evoked SEP studies suggests that these pain‐related inputs to the primary somatosensory cortex are largely inhibitory.
Exteroceptive suppression of temporalis and masseter muscle activity is enhanced in offspring of hypertensives
Authors: FRANCE CHRISTOPHER R. , FRENCH DOUGLAS J. , PAGE GARY D. , BONK VALERIE A. , MEADE MICHELLE A. , STEWART KATHRYN M. , HOLROYD KENNETH A.
Published: February 2007

Exteroceptive suppression of temporalis and masseter muscle activity was examined in young men with and without a parental history of hypertension. Recent clinical studies suggest that the second exteroceptive suppression period is attenuated in several chronic pain disorders and that this brainstem reflex may serve as a noninvasive index of endogenous pain control. In the present study, offspring of hypertensives exhibited a significant protraction of the late exteroceptive suppression period for both muscle sites, suggesting that the decreased pain sensitivity previously observed in individuals at risk for hypertension may be related to enhanced central pain modulation.
Cardiac rhythmicities and attention in young children
Authors: HYDE CHRISTOPHER , IZARD CARROLL E.
Published: February 2007

This study examined the changes in three cardiac rhythmicities (angiotensin‐renin vasomotor [ARV], Traube‐Hering‐Meyer [THM], and respiratory sinus arrhythmia [RSA]) during prolonged attention in preschool children. Electrocardiogram data were collected from children during resting baseline and a 5‐min attention condition at ages 3, 4, and 5 years in a longitudinal study. The ARV and THM rhythmicities decreased during prolonged attention for most participants. The RSA rhythmicity did not change consistently. The results were replicated at all three ages. The ARV and THM effect sizes were large and moderate, respectively. Only the ARV decrease correlated with duration of attention.
Effects of item repetitions and variations on the efficiency of the guilty knowledge test
Authors: ELAAD EITAN , BEN‐SHAKHAR GERSHON
Published: February 2007

Two mock‐crime experiments were designed to examine the effects of question repetition and variation on the efficiency of the guilty knowledge test. In the first experiment, two factors (single vs. multiple questions, and high vs. low motivation) were manipulated and in the second experiment, which was an analog study conducted in a police laboratory using field equipment, only the first factor was examined. Similar detection efficiencies were obtained in both experiments when a single question was repeated 12 times, and when each of four different questions was repeated 3 times. The results also showed that accumulating information across repetitions and across physiological measures tended to increase detection efficiency and reduce false positive errors. The results of Experiment 1 suggest that motivation to avoid detection may be associated with better detection efficiency.
On the utility of P3 latency as an index of mental chronometry
Authors: Verleger Rolf
Published: February 2007

The stimulus evaluation view on P3 latency holds that P3 latency mainly reflects stimulus‐processing time, in contrast to response‐processing lime. A review of the experimental evidence, however, leads to the conclusion that P3 is not a sensitive tool for separating between stimulus and response‐related processes. Rather, it appears that P3 latency is a sensitive index of any response‐time changes when response times in the fast condition are brief, with its sensitivity decreasing when response times in the fast condition get longer. This regularity was confirmed by a detailed analysis of the published evidence from Steinberg's task and was not attributable to speed‐accuracy trade‐off or to different methods of parameterization. The structures generating the scalp P3b are involved both in stimulus processing and in response selection. Response selection may exert its effect on P3 in one of two ways: either directly, fully delaying P3 latency, or affecting a second P3 component (P‐CR) only, thus having an attenuated effect on P3 latency.
The effect of adrenergic blockade on blushing and facial flushing
Authors: DRUMMOND PETER D.
Published: February 2007

The effect of adrenergic blockade on vascular responses in the forehead was assessed during stressful mental arithmetic, singing, and moderate exercise in 21 frequent blushers and 21 infrequent blushers. Adrenergic antagonists were introduced into a small site on the forehead by iontophoresis, and vascular responses were monitored bilaterally with laser Doppler flowmetry. Beta blockade prevented increases in blood flow in infrequent blushers during mental arithmetic and partially inhibited vasodilatation during singing, indicating minor participation of β‐adrenoccptors in blushing. Alpha blockade did not affect blushing but augmented vasodilatation during exercise. Despite higher ratings of self‐consciousness in frequent than in infrequent blushers, vascular responses were similar in both groups. Thus, blushing propensity does not appear to be related to the density of α or β‐adrenoceptors in facial vessels and may have a psychological basis.
Electrophysiological evidence for cross‐modal plasticity in humans with early‐ and late‐onset blindness
Authors: KUJALA T. , ALHO K. , HUOTILAINEN M. , ILMONIEMI R. J. , LEHTOKOSKI A. , LEINONEN A. , RINNE T. , SALONEN O. , SINKKONEN J. , STANDERTSKJÖULD‐NORDENSTAM C.‐G. , NÄUÄUTÄUNEN R.
Published: February 2007

It is commonly believed that sensory deprivation can lead to cross‐modal reorganization in an immature hut not in a mature brain. The results of the present study suggest, however, that plasticity between sensory modalities is possible even in adults: activity indicating involvement of parietal or occipital brain areas in pitch‐change discrimination was found in individuals blinded after childhood. Event‐related brain potentials of early blinded (before the age of 2 years). late‐blinded (12–28 years of age), and sighted adults were recorded to stimulus sequences consisting of standard tones occasionally replaced by deviant tones. Even when participants were not attending to auditory stimuli, the deviant tones elicited the mismatch negativity (MMN) in each group. There were no significant MMN front‐back scalp distribution differences among the groups. However, when participants were detecting deviant stimuli, these stimuli elicited N2 and P3 waves that were posterior in distribution in both groups of blind participants relative to those of the sighted participants. These results suggest that cross‐modal reorganization may occur even in the mature human brain.
Heart rate variability: Origins, methods, and interpretive caveats
Authors: BERNTSON GARY G. , THOMAS BIGGER J. , ECKBERG DWAIN L. , GROSSMAN PAUL , KAUFMANN PETER G. , MALIK MAREK , NAGARAJA HAIKADY N. , PORGES STEPHEN W. , SAUL J. PHILIP , STONE PETER H. , VAN DER MOLEN MAUROTS W.
Published: February 2007

Components of heart rate variability have attracted considerable attention in psychology and medicine and have become important dependent measures in psychophysiology and behavioral medicine. Quantification and interpretation of heart rate variability, however, remain complex issues and are fraught with pitfalls. The present report (a) examines the physiological origins and mechanisms of heart rate variability, (b) considers quantitative approaches to measurement, and (c) highlights important caveats in the interpretation of heart rate variability. Summary guidelines for research in this area are outlined, and suggestions and prospects for future developments are considered.
Cardiovascular recovery from stress and hypertension risk factors: A meta‐analytic review
Authors: HOCKING SCHULER JENNIFER L. , O'BRIEN WILLIAM H.
Published: February 2007

Recent research has suggested that cardiovascular recovery from stress can play a potential role in hypertension pathogenesis. Sixty nine studies were included in meta analytic review to evaluate the effect of various hypertension risk factors (e.g., race, lack of exercise) on cardiovascular recovery from stress. Small mean effect sized were observed for studies examining hypertension status and race as risk factors associated with delayed diastolic blood pressure recovery. Lack of fitness was also associated with delayed heart rate recovery. These results revealed that, for the specified risk factors and cardiovascular variables, high risk individuals exhibited delayed cardiovascular recovery as compared with low risk individuals. Further, the relationships between hypertension status, race and cardiovascular recovery were typically associated with the use of “ctive” laboratory stressors. The relationship between lack of fitness and cardiovascular recovery was also associated with the use of “active” and exercise laboratory stressors.
Startle reflex modulation by pleasant and unpleasant odors in a between‐subjects design
Authors: EHRLICHMAN HOWARD , BROWN KUHL SANDRA , ZHU JOHN , WRRENBURG STEPHEN
Published: February 2007

Participants were presented with an acoustic startle probe while they smelled either a pleasant odor or an unpleasant odor (n = 40 pet condition). Within each condition, participants were presented with lour blocks in which odor was present and four in which odor was not present (no‐odor control). Significant differences were found in both conditions between the odor and no‐odor blocks. In the unpleasant odor condition, blink magnitude was greater during the odor blocks; in the pleasant odor condition, blink magnitude was smaller during the odor blocks.
Daily mood states and ambulatory blood pressure
Authors: SHAPIRO DAVID , JAMNER LARRY D. , GOLDSTEIN IRIS B.
Published: February 2007

In 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

Conditioned 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

In 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

The 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

In 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

The 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

A 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

The 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

When 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

Aim:  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.
Soil acidification and aluminium mobility
Authors: Bache B. W.
Published: February 2007

Abstract. Natural acidification processes result in increasing solubility of aluminium as soils become more acid. Exchangeable aluminium provides a large reserve that can be mobilized by percolating acids or salts, with solution pH determining the upper limit of its solubility. Aluminium can also be mobilized within soils and into drainage waters in soluble complexes with silica or fluoride, and in organically complexed forms.
Soil acidity factors and growth of white clover (Trifolium repens L.) in acid hill soils
Authors: Wood M. , Cooper J.E.
Published: February 2007

Abstract.Correlation analysis was used to determine the main factors related to soil pH and to yield of white clover in a range of hill soils. Results for 109 Northern Ireland pasture soils showed that pH (H2O) was significantly correlated with exchangeable Ca, total exchangeable bases, base saturation, P, exchangeable Al and Al saturation, but not with exchangeable Mn. Clover yield (dry weight of shoots) in 12 acid soils from Northern Ireland, Scotland and the Falkland Islands was significantly correlated with exchangeable Ca, total exchangeable bases and Al saturation. The results support the use of Al saturation rather than exchangeable Al, soil solution Al or pH when calculating lime requirements to overcome these limiting factors in hill soils.
Swedish experiments on subsoil compaction by vehicles with high axle load
Authors: Håkansson Inge
Published: February 2007

Abstract. Soil and crop responses to traffic with vehicles having an axle load of 10 tonnes were studied in 9 field experiments. The clay content of the soils ranged from 6 to 85%. The traffic resulted in increased soil bulk density and strength to a depth of 50 cm. Compaction effects persisted below plough depth 7–8 years after traffic. Crop response was negative and increased with clay content of the soil and with traffic intensity and decreased with time. The results indicate that maximum axle loads on arable fields should be less than 10 tonnes, especially on clay soils.
Bulk soil handling for quarry restoration
Authors: Ramsay W.J.H.
Published: February 2007

Abstract. The principles and practice of bulk soil handling for mine reclamation are reviewed, with special reference to the agricultural restoration of sand and gravel quarries in the UK. The principal forms of damage to soils when moved are due to trafficking, and include compaction in cohesive soils and loss of structure in granular soils. Of the wide range of soil moving equipment available, earthscrapers are often responsible for severe compaction. New soil handling techniques have been developed to minimize such damage. On chalky boulder clay soils earthscrapers can be combined with excavators for topsoil placement. On more granular soils all soil handling can be carried out by excavators and dumptrucks, with virtually immediate restoration to full agricultural productivity.
Nitrate leaching from a small, underdrained, grassland, clay catchment
Authors: Haigh Rosalyn A. , White R.E.
Published: February 2007

Abstract. Losses of nitrogen in the tile drainflow from a clay soil (Evesham series) under grazed grassland were monitored during the 1982/83 and 1983/84 drainflow seasons. In 1982/83, 40% of the discharge had a NO3− concentration > 11.3 mgNl−1, while in 1983/84 concentrations were always > 20 mgNl−1. Total N lost by leaching was 17.5 and 48.7 kg ha−1 in 1982/83 and 1983/84 respectively, which was equivalent to 9 and 43% of the fertilizer applied. The marked difference in N losses for the two seasons was attributed to differences in the quantity and timing of N fertilizer applications, the dryness of the preceding summer and the duration and density of stocking.
Water use efficiencies in relation to sugarcane yields
Authors: Yates R.A. , Taylor R.D.
Published: February 2007

Abstract. The literature indicates that cane yield‐tonnes cane per hectare (tc ha−1)‐is directly related to actual evapotranspiration (Et) and that a ratio 1 tc ha−1 cm−1 Et should be a reasonable objective; this is frequently not attained in commercial practice. Analysis of extensive data from non‐irrigated cane in upland Kenya demonstrated water use efficiencies of 0.5 to 0.6 tc ha−1 cm−1 Et in relationships which were remarkably precise; some of the reasons for the failure to achieve higher efficiencies at this location are discussed. The practice of irrigation is likely to introduce additional complications and so reduce water use efficiencies even further; thus responses to irrigation should be measured experimentally before capital expenditure is approved. The main additional complications are the interactions between irrigation and soil type on rooting and growth, in particular the influence of soil type on yield responses; and the fact that advective energy interferes with the convenient, direct relationships between radiation and evaporation and yield.
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.
An improved method for combining map data
Authors: King D. , Daroussin J. , Bonneton P. , Nicoullaud B.
Published: February 2007

Abstract. A system is described using data processed to combine maps from different sources in order to meet specific needs. The system, known as the KALEIDOS‐INRA system, has many advantages over traditional map making and provides the user with better information. Its value is illustrated by a map showing the risk of drought to crops growing in central France.
Classification and assignment in soil science
Authors: Gordon A.D.
Published: February 2007

Abstract.The paper presents an introduction to automated methods of classification and assignment, with particular reference to their use in the analysis of soil data. Material covered includes: types of variable describing a soil sample; measures of dissimilarity; clustering criteria and algorithms; representation of data as points in a low‐dimensional space; assessment of classifications; incorporation into a classification of spatial relationships between soil samples; assignment of objects to the population with maximum posterior probability; assignment procedures for data described by variables of mixed type; kernel density estimation; assignment to spatially‐located populations.
Geostatistics and its application to soil science
Authors: Oliver M.A.
Published: February 2007

Abstract. Geostatistics is principally the application of regionalized variable theory. The methods it embodies are applicable throughout the earth sciences for investigating the spatial variation of, and for estimating continuous random variables. The semi‐variogram is the central tool of geostatistics. It can quantify the scale and intensity of spatial variation and it provides the essential spatial information for local estimation by kriging and for optimizing sample intensity. It can also be used in an exploratory manner to try to discover underlying causes of the variation. Geostatistical methods have been widely applied in the mining industry and there are many examples of their application in soil science. Their use is illustrated by a case study of soil spatial variation in the Wyre Forest of England.
Mapping and map analysis: new tools for land evaluation
Authors: Burrough P.A.
Published: February 2007

Abstract. Rural planning studies require knowledge about the attributes and spatial distributions of the natural resources of areas to be developed. When these data are available only in the form of paper maps simple technology limits the planner in the number of questions that can be answered quickly and effectively. Geographical information systems now enable mapped data to be stored and linked to other relevant spatial information so that many kinds of questions about the natural resources can be answered, and various scenarios can be compared before they are carried out. The methods used for data analysis in geographical information systems are explained briefly and are illustrated by using an example of locating a simple earth dam in a small catchment in Kisii District, Kenya. Although these new tools are often technically excellent, the results they give can be no better than the quality of the data and the models used for analysis allow. There is still much work to he done on the propagation of errors in geographical analysis, whether done with the aid of the computer or not.
Soil failure and force prediction for soil engaging discs
Authors: Godwin R.J. , Seig D.A. , Allott M.
Published: February 2007

Abstract. The soil forces acting upon agricultural discs arise from both a passive reaction on the concave face and scrubbing reaction on the convex face. The magnitude of these reactions is a function of both the disc geometry, primarily the radius of the sphere from which the disc is formed, and the angle of the disc to the direction of travel. These forces can be predicted within acceptable limits using soil mechanics theories based upon Mohr‐Coulomb properties. From both the theoretical and practical results optimum disc setting can be selected to give low specific resistance values. The prediction model has been successfully used with stress analysis techniques to design new disc geometries and, with the advent of improved materials, to select appropriate disc thicknesses.
Crop and soil response to subsoil loosening, deep incorporation of phosphorus and potassium fertilizer and subsequent soil management on a range of soil types.: Part 1: Response of arable crops
Authors: Marks M.J. , Soane G.C.
Published: February 2007

Abstract. Between 1978 and 1985 16 experiments tested crop response to subsoil loosening by either the Wye Double Digger or a winged subsoiler. Additionally, response to incorporation of 350 kg ha of P2O5and K2O into the subsoil was tested. Soil types were mainly well‐drained light‐and medium‐textured soils in arable rotations. Subsoil loosening increased the yield of spring‐sown crops on sandy soils in years of moderate to severe drought. Response was associated with deeper rooting and improved water extraction from the subsoil. No yield increases were recorded with autumn‐sown crops which were largely grown on the medium and heavy textured soils. There was a trend towards yield reductions on deep silty soils in wetter years. At one site only did the response to phosphorus and potassium fertilizer incorporated into the subsoil exceed that of fertilizer applied to the topsoil.
The effect of large applications of pig slurry on the strength of soil under grass
Authors: Stevens R.J. , Laughlin R.J. , Logan H.J. , Gracey H.I.
Published: February 2007

Abstract. The effect of eight years of applications of five rates (0, 134, 269, 538 and 1075 m3 ha−1 a−1) of pig slurry on the soil strength two years later were studied in a field experiment. Soil strength in the 0–150 mm depth was measured on five occasions in winter using a hand‐held recording cone penetrometer. On one occasion the penetration resistance at some depths greater than 100 mm was significantly (P < 0.001) decreased by adding more than 269 m3 of slurry ha−1 a−1. On three occasions different amounts of slurry caused significant differences in the rate of increase of penetration resistance with depth. Large applications of slurry may decrease penetration resistance because they increase organic matter, thereby increasing the water retention of the soil.
Physico‐chemical controls on artificial radionuclides in soil
Authors: Livens F.R. , Rimmer D.L.
Published: February 2007

Abstract. Radionuclides in the environment come from a wide range of sources, some natural and some artificial. Their biogeochemical behaviour is influenced both by their own physico‐chemical properties and by those of the soil with which they interact. The source of the radionuclides is important, as are any changes in physico‐chemical characteristics that occur during transport and deposition. Once in the soil further reactions can occur as the radionuclides equilibrate. These include immobilization by ion exchange and precipitation and remobilization by complexing and dissolution. Land management and environmental changes that alter conditions in the soil result in changes in the interactions of radionuclides with the soil and thereby to changes in mobility in the soil.
Models for radionuclide transport in soils
Authors: Coughtrey P.J.
Published: February 2007

Abstract. Mathematical models describing radionuclide transport in soil developed for radiological assessment have increased in complexity over the last decade. In particular fairly simple ‘black box’, equilibrium approaches have given way to more complex, time‐dependent, process‐orientated methods. The increase in complexity of these models has outstripped the available data to specify, test and validate them. Current issues in model development include those that are associated with times up to a million years. Further development requires new laboratory and field research to provide adequate data to justify the inclusion or omission of known soil processes.