We compared the accuracy of momentary time sampling (MTS) and partial interval recording (PIR) in estimating both absolute behavioral levels and relative change. A computer randomly generated runs of pseudobehavior varying in duration and rate and simulated MTS and PIR of each run. Results indicated that when estimating absolute behavioral levels, duration rather than rate should be used as the dependent measure, and MTS is more accurate than PIR. In contrast, PIR is the more sensitive method for detecting relative changes in behavioral levels, although, at high rates, PIR tends to underestimate the degree of change.
observation methods; momentary time sampling; partial interval recording; measurement error
Emotion dysregulation is thought to be critical to the development of negative psychological outcomes. Gross (1998b) conceptualized the timing of regulation strategies as key to this relationship, with response-focused strategies, such as expressive suppression, as less effective and more detrimental compared to antecedent-focused ones, such as cognitive reappraisal. In the current study, we examined the relationship between reappraisal and expressive suppression and measures of psychopathology, particularly for stress-related reactions, in both undergraduate and trauma-exposed community samples of women. Generally, expressive suppression was associated with higher, and reappraisal with lower, self-reported stress-related symptoms. In particular, expressive suppression was associated with PTSD, anxiety, and depression symptoms in the trauma-exposed community sample, with rumination partially mediating this association. Finally, based on factor analysis, expressive suppression and cognitive reappraisal appear to be independent constructs. Overall, expressive suppression, much more so than cognitive reappraisal, may play an important role in the experience of stress-related symptoms. Further, given their independence, there are potentially relevant clinical implications, as interventions that shift one of these emotion regulation strategies may not lead to changes in the other.
Emotion regulation; expressive suppression; reappraisal; trauma; stress
Antisocial and criminal behaviors are multifactorial traits whose interpretation relies on multiple disciplines. Since these interpretations may have social, moral and legal implications, a constant review of the evidence is necessary before any scientific claim is considered as truth. A recent study proposed that men with wider faces relative to facial height (fWHR) are more likely to develop unethical behaviour mediated by a psychological sense of power. This research was based on reports suggesting that sexual dimorphism and selection would be responsible for a correlation between fWHR and aggression. Here we show that 4,960 individuals from 94 modern human populations belonging to a vast array of genetic and cultural contexts do not display significant amounts of fWHR sexual dimorphism. Further analyses using populations with associated ethnographical records as well as samples of male prisoners of the Mexico City Federal Penitentiary condemned by crimes of variable level of inter-personal aggression (homicide, robbery, and minor faults) did not show significant evidence, suggesting that populations/individuals with higher levels of bellicosity, aggressive behaviour, or power-mediated behaviour display greater fWHR. Finally, a regression analysis of fWHR on individual's fitness showed no significant correlation between this facial trait and reproductive success. Overall, our results suggest that facial attributes are poor predictors of aggressive behaviour, or at least, that sexual selection was weak enough to leave a signal on patterns of between- and within-sex and population facial variation.
Objective—A mathematical model of modulated ventricular parasystole based on the relation between the coupling interval and the preceding RR interval was developed in an attempt to distinguish between parasystolic automaticity and other mechanisms.
Mathematical model—The relation between the coupling interval and the preceding RR interval was examined by plotting the coupling interval of each extrasystole against the preceding RR interval (coupling interval/RR diagram). The coupling interval/RR diagrams obtained from simulations with various modulation modes suggested that the parasystolic mechanism was likely when the dots representing extrasystoles appeared as discrete clusters. In contrast, a linear horizontal accumulation of dots indicated a non-parasystolic mechanism.
Clinical observation—To verify the validity of the simulations, 24 hour electrocardiographic recordings from 60 patients with frequent ventricular extrasystoles (>1000/day) were analysed to determine whether the extrasystoles showed intrinsic periodicity. Intrinsic periodicity indicative of a parasystolic mechanism was seen in 14 (93%) of 15 patients in whom the coupling interval/RR diagram was characteristic of a parasystolic mechanism. When the coupling interval did not change (variability <200 ms) over a wide range of RR intervals (>700 ms) intrinsic periodicity was never identified (0/17). Parasystolic automaticity was the likely mechanism in 11 of the remaining 28 patients (39·3%) in whom coupling interval/RR diagrams were not definitive.
Conclusion—These data indicate that definite patterns of coupling interval/RR diagrams can be used to distinguish between parasystolic and non-parasystolic mechanisms.
This study examined the percentage time estimates of momentary time sampling against the real time obtained with handheld computers in a natural setting. Twenty-two concurrent observations were conducted in elementary schools by one observer who used 15-s momentary time sampling and a second who used a handheld computer. Results for the six behaviors showed a close correspondence between the momentary time sampling percentage observation intervals and the real time percentage observation time, although 15-s momentary time sampling tended not to sample low-frequency short-duration behaviors. The results confirmed laboratory findings that short-interval momentary time sampling estimates percentage time accurately for a wide range of behavior frequencies and durations, and suggested that observers using momentary time sampling in a natural setting are able to obtain accurate data.
time sample; methodology; naturalistic observations
The optimum daily dose of thyroxine was calculated for 13 children aged 3-16 years with primary hypothyroidism by titrating their doses at monthly intervals. The condition of the thyroid was assessed by sensitive assay of thyroid stimulating hormone concentrations, as well as measurement of total and free thyroid hormone concentrations and systolic time interval ratios. Serum thyroid stimulating hormone concentration was found to be the most responsive to small changes in thyroxine. The calculated optimum daily replacement dose of thyroxine (102 micrograms/m2 or 3.5 micrograms/kg) was fractionally lower than that previously recommended, and was more closely related to surface area (coefficient of variation 8.2%) than to body weight (coefficient of variation 16.2%). Our results suggest that though monthly may be the optimal time interval for increases in the dose of thyroxine, any reduction in the dose should be made more gradually.
The extant data for pigeons' performance on concurrent variable-interval schedules were examined in detail. Least-squares lines relating relative pecks and time to the corresponding relative reinforcements were obtained for four studies. The between-study group slopes for time and pecks and five of seven within-study group slopes from individual studies were less than 1.00. This suggested the generality that pigeons respond less to the richer reinforcement schedule than predicted by matching. For pecks, a nonparametric test for distribution of points also supported this concept of undermatching (to the richer reinforcement schedule). In addition, using mean squared error as the criterion, a cubic curve fit the peck proportion data better than any line or other polynomial. This indicates that the relation between peck and reinforcement proportions may be nonlinear.
undermatching concurrent variable-interval schedules; matching; pigeons
Pigeons were trained on a Wyckoff observing response procedure in which key responses were reinforced on a mixed schedule consisting of fixed-interval and extinction components. In Experiment 1, stepping on a pedal (a) converted the mixed schedule to a multiple schedule, (b) replaced the mixed-schedule stimulus with an unlit key (or, in different phases, a blackout), or (c) had no consequence. In Experiment 2, pedal standing removed the mixed-schedule stimulus that was physically similar to the multiple-schedule stimuli or one that was less similar. In Experiment 3, Wyckoff's differential and nondifferential discrimination procedure was repeated. The results of Experiments 1 and 2 showed that the Wyckoff pedal response was controlled by neither the removal of the mixed-schedule stimulus nor the production of discriminative stimuli. The results indicated a correlation between key-response rates and pedal-standing time. Experiment 3 showed that high response rates to mixed-schedule stimuli were correlated with little pedal-standing time while high key-response rates to multiple-schedule stimuli were correlated with considerable pedal standing time. The correlation between key-response rates and pedal-standing time was related to the physical arrangement between the key and pedal operanda.
Studies on familial aggregation of cancer may suggest an overall contribution of inherited genes or a shared environment in the development of malignant disease. We performed a meta-analysis on familial clustering of prostate cancer. Out of 74 studies reporting data on familial aggregation of prostate cancer in unselected populations retrieved by a Pubmed search and browsing references, 33 independent studies meeting the inclusion criteria were used in the analysis performed with the random effects model. The pooled rate ratio (RR) for first-degree family history, i.e. affected father or brother, is 2.48 (95% confidence interval: 2.25–2.74). The incidence rate for men who have a brother who got prostate cancer increases 3.14 times (CI:2.37–4.15), and for those with affected father 2.35 times (CI:2.02–2.72). The pooled estimate of RR for two or more affected first-degree family members relative to no history in father and in brother is 4.39 (CI:2.61–7.39). First-degree family history appears to increase the incidence rate of prostate cancer more in men under 65 (RR:2.87, CI:2.21–3.74), than in men aged 65 and older (RR:1.92, CI:1.49–2.47), p for interaction = 0.002. The attributable fraction among those having an affected first-degree relative equals to 59.7% (CI:55.6–63.5%) for men at all ages, 65.2% (CI:57.7–71.4%) for men younger than 65 and 47.9% (CI:37.1–56.8%) for men aged 65 or older. For those with a family history in 2 or more first-degree family members 77.2% (CI:65.4–85.0%) of prostate cancer incidence can be attributed to the familial clustering. Our combined estimates show strong familial clustering and a significant effect-modification by age meaning that familial aggregation was associated with earlier disease onset (before age 65).
A rapid and simple screening test for detecting cystic fibrosis, described in 1956, has been used routinely for 21 years; the results during a 15-month period are compared with those using the quantitative pilocarpine iontophoresis sweat test. In the chloride agar plate test the concentration of chloride on the finger tips is evaluated accordingly to the intensity of the imprint. Readings of 2+ or less excluded cystic fibrosis in 1589 cases with only two doubtful instances, whereas 4+ readings were recorded in 198 cases of cystic fibrosis and 3+ readings in 15 cases of cystic fibrosis. In doubtful cases 4 individuals had 4+ readings and 11 had 3+ readings. This screening test does not replace the quantitative pilocarpine iontophoresis test but it does identify an individual who is likely to have the disease and who requires further tests. It is not reliable for infants aged under 2 months.
This research examined the benefits of interpreting physiological arousal as a challenge response on practice and actual Graduate Record Examination (GRE) scores. Participants who were preparing to take the GRE reported to the laboratory for a practice GRE study. Participants assigned to a reappraisal condition were told arousal improves performance, whereas control participants were not given this information. We collected saliva samples at baseline and after the appraisal manipulation, which were then assayed for salivary alpha amylase (sAA), a measure of sympathetic nervous system activation. Reappraisal participants exhibited a significant increase in sAA and outperformed controls on the GRE-math section. One to three months later, participants returned to the lab and provided their score reports from their actual GRE. Again, reappraisal participants scored higher than controls on the GRE-math section. These findings illuminate the powerful influence appraisal has on physiology and performance both in and out of the laboratory.
A person manufactured his in-seat behavior for 15, 30-min sessions so that there were three blocks of five sessions where the behavior occurred 20%, 50%, and 80% of the time. Whole interval, partial interval, and momentary time-sample measures of the behavior were taken and compared to the continuous measure of the behavior i.e., per cent of time the behavior occurred. For interval time sampling, the difference between the continuous and sample measures i.e., measurement error, was: (1) extensive, (2) unidirectional, (3) a function of the time per response, and (4) inconsistent across changes in the continuous measure. A procedural analysis demonstrated that the frequency and duration of behavior are confounded in interval time sampling. Momentary time sampling was found to be superior to interval time sampling in estimating the duration a behavior occurs.
time sampling; partial interval; whole interval; momentary; measurement error
There is evidence that various meditation practices reduce distress, but little is known about the mechanisms of frequently repeating a mantram—a spiritual word or phrase—on distress reduction. Mantram repetition is the portable practice of focusing attention frequently on a mantram throughout the day without a specific time, place or posture.
We examined the hypothesis of whether increases positive reappraisal coping or distancing coping mediated the sustained decreases in anger found following a group-based mantram intervention that was designed to train attention and promote awareness of internal experiences.
A secondary analysis was performed on data collected from a randomized controlled trial that compared a group-based mantram intervention (n=46) to an attention-matched control (n = 47) in a community sample of HIV-positive adults. Positive reappraisal and distancing coping were explored as potential mediators of anger reduction.
Participants in the mantram intervention reported significant increases in positive reappraisal coping over the 5-week intervention period whereas the control group reported decreases. Increases in positive reappraisal coping during the 5-week intervention period mediated the effect of mantram on decreased anger at 22-week follow-up.
Findings suggest that a group-based mantram intervention may reduce anger by enhancing positive reappraisal coping.
Acceptance-Based Responding; Anger; Cognitive Coping; HIV Intervention; Meditation; Meta-cognition; Spirituality
The light-driven enzyme protochlorophyllide oxidoreductase (POR) catalyzes the reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide). This reaction is a key step in the biosynthesis of chlorophyll. Ultrafast photochemical processes within the Pchlide molecule are required for catalysis and previous studies have suggested that a short-lived excited-state species, known as I675*, is the first catalytic intermediate in the reaction and is essential for capturing excitation energy to drive subsequent hydride and proton transfers. The chemical nature of the I675* excited state species and its role in catalysis are not known. Here, we report time-resolved pump-probe spectroscopy measurements to study the involvement of the I675* intermediate in POR photochemistry. We show that I675* is not unique to the POR-catalyzed photoreduction of Pchlide as it is also formed in the absence of the POR enzyme. The I675* species is only produced in samples that contain both Pchlide substrate and Chlide product and its formation is dependent on the pump excitation wavelength. The rate of formation and the quantum yield is maximized in 50∶50 mixtures of the two pigments (Pchlide and Chlide) and is caused by direct energy transfer between Pchlide and neighboring Chlide molecules, which is inhibited in the polar solvent methanol. Consequently, we have re-evaluated the mechanism for early stage photochemistry in the light-driven reduction of Pchlide and propose that I675* represents an excited state species formed in Pchlide-Chlide dimers, possibly an excimer. Contrary to previous reports, we conclude that this excited state species has no direct mechanistic relevance to the POR-catalyzed reduction of Pchlide.
The authors conducted an experience sampling study to investigate the relationship between momentary ruminative self-focus and negative affect. Ninety-three adults recorded these variables at quasi-random intervals 8 times daily for 1 week. Scores on questionnaire measures of dispositional rumination were associated with mean levels of momentary ruminative self-focus over the experience sampling week. Concurrently, momentary ruminative self-focus was positively associated with negative affect. Cross-lagged analyses revealed that whereas ruminative self-focus predicted negative affect at a subsequent occasion, negative affect also predicted ruminative self-focus at a subsequent occasion. Decomposition of the dispositional rumination measure suggested that brooding, but not reflective pondering, was associated with higher mean levels of negative affect. Though broadly consistent with Nolen-Hoeksema's (1991) response styles theory, these results suggest that a reciprocal relationship exists between ruminative self-focus and negative affect.
depression; rumination; self-focus; experience sampling; affect
In the current study, momentary time sampling (MTS) and partial-interval recording (PIR) were compared to continuous-duration recording of stereotypy and to the frequency of self-injury during a treatment analysis to determine whether the recording method affected data interpretation. Five previously conducted treatment analysis data sets were analyzed by creating separate graphic displays for each measurement method (duration or frequency, MTS, and PIR). An expert panel interview and structured criterion visual inspection were used to evaluate treatment effects across measurement methods. Results showed that treatment analysis interpretations based on both discontinuous recording methods often matched those based on frequency or duration recording; however, interpretations based on MTS were slightly more likely to match those based on duration and those based on PIR were slightly more likely to match those based on frequency.
measurement; momentary time sampling; partial-interval recording
Fatigue in chronic fatigue syndrome (CFS) is usually assessed with retrospective measures rather than real-time momentary symptom assessments. In this study, the authors hypothesized that in participants with CFS, discrepancies between recalled and momentary fatigue would be related to catastrophizing, anxiety, and depression and to variability of momentary fatigue. They also expected that catastrophizing, anxiety, and depression would be associated with momentary fatigue. The authors asked 53 adults with CFS to carry electronic diaries for 3 weeks and record their experiences of momentary fatigue. The authors assessed participants' fatigue recall with weekly ratings and administered questionnaires for catastrophizing, depression, and anxiety. Recall discrepancy was significantly related to the variability of momentary fatigue. In addition, catastrophizing, depression, and momentary fatigue were all significantly related to recall discrepancy. Catastrophizing, depression, anxiety, and momentary negative affect were all significantly associated with momentary fatigue. The findings suggest that momentary fatigue in patients with CFS is related to modifiable psychological factors.
affect; chronic fatigue syndrome; fatigue; measurement; pain
Continuous and time-sample measures of the in-seat behavior of a secretary were obtained. Measurement error, i.e., the extent to which the sample measures deviated from the continuous measure, was a function of the frequency of the sample measurements and the criterion used to score an example of the behavior. If the behavior had to be exhibited throughout the observational interval (whole-interval time sampling), there was a consistent underestimate of the continuous measure. If the behavior had to be exhibited only briefly within the observational interval (partial-interval time sampling), there was a consistent overestimate of the continuous measure. And, if the behavior had to be exhibited at the end of the observational interval (momentary time sampling), overestimations and underestimations of the continuous measure occurred about equally often. As expected, the more frequently the sample measures were made the closer was the agreement between the sample and continuous measures. Two conclusions concerning measurement error in interval time sampling were made. The first was that the error will be a function of the mean time per response. The second is that this error will not be consistent across experimental conditions.
time sampling; whole interval; partial interval; momentary; measurement error; continuous versus time-sample recording
We designed a series of analyses to develop a measurement system capable of simultaneously recording the free-play patterns of 20 children in a preschool classroom. Study 1 determined the intermittency with which the location and engagement of each child could be momentarily observed before the accuracy of the measurement was compromised. Results showed that intervals up to 120 s introduced less than 10% measurement error. Study 2 determined the extent of agreement between two observers who simultaneously collected data for 20 children using 30-, 60-, 90-, and 120-s momentary time sampling (MTS) intervals. The three larger intervals resulted in high levels of interobserver agreement (above 90%), whereas the 30-s interval resulted in unacceptably low levels of agreement (less than 80%). By allowing observers to select from among the different MTS intervals via a datasheet array and then collect data with the chosen system, Study 3 determined observers' preferences for the remaining MTS intervals. Both data collectors preferred the 90-s MTS procedure. The sensitivity of the 90-s MTS procedure, which was shown to be accurate, reliable, and preferred, was then demonstrated by its use to describe activity preferences of a classroom of children in Study 4. This system identified high- and low-preference activities for individual children and revealed interesting patterns of response allocation by the group.
choice; free play; measurement; momentary time sampling; preference assessment; preschoolers
Accurate incidence information is required to plan and evaluate screening programmes which have been proposed for the detection of primary toxoplasmosis and cytomegalovirus infection in pregnancy. Appropriate statistical methods are described for deriving incidence rates and their confidence intervals from three types of data: change in age-specific seroprevalence, seroconversion, and IgM studies. These methods are applied to seven published studies on toxoplasmosis and cytomegalovirus carried out in the UK. In these publications only one estimate of the infection rate per pregnancy was correctly derived, and none were accompanied by confidence intervals. Using the proposed methods, most estimates of the primary toxoplasmosis rate in these studies were between 2.5 and 5.5 per 1000 pregnancies, compared to the 2 per 1000 usually cited. Most cytomegalovirus incidence estimates were between 4 and 10 per 1000 pregnancies.
Brain protection during aortic arch surgery by perfusing cold oxygenated blood into the superior vena cava was first reported by Lemole et al. In 1990 Ueda and associates first described the routine use of continuous retrograde cerebral perfusion (RCP) in thoracic aortic surgery for the purpose of cerebral protection during the interval of obligatory interruption of anterograde cerebral flow. The beneficial effects of RCP may be its ability to sustain brain hypothermia during hypothermic circulatory arrest (HCA) and removal of embolic material from the arterial circulation of the brain. RCP can offer effective brain protection during HCA for about 40 to 60 minutes. Animal experiments revealed that RCP provided inadequate cerebral perfusion and that neurological recovery was improved with selective antegrade cerebral perfusion (ACP), however, both RCP and ACP provide comparable clinical outcomes regarding both the mortality and stroke rates by risk-adjusted and case-matched comparative study. RCP still remains a valuable adjunct for brain protection during aortic arch repair in particular pathologies and patients.
Aortic arch surgery; brain protection; retrograde cerebral perfusion; hypothermic circulatory arrest
More than one and half of current cases of hepatocellular carcinoma in the US, Europe, and Japan are attributable to hepatitis C virus (HCV) infection. HCV is also the primary cause of death in patients with HCV-related cirrhosis, with annual incidences of 0.5%–5% in Europe and 4%–10% in Asia. Screening is based on serum alpha-fetoprotein determination and liver ultrasound scan, but the sensitivity of the former is far less than optimal, and screening intervals are still poorly defined for the latter. Risk factors related to the host or environment, or both, appear to be more relevant than viral factors, such as HCV genotype, in determining disease progression to cirrhosis and cancer, and include age, male gender, severity of liver disease at presentation, coinfection with hepatitis B virus or human immunodeficiency virus, and alcohol abuse. Early liver transplantation in selected cases can be curative, but most patients are not eligible for liver grafting and are treated with locoregional ablative therapies, after which recurrence is common. Recently, orally available inhibitors of the vascular endothelial growth factor receptor have shown a significant, albeit modest, increment of survival in patients with advanced hepatocellular carcinoma, thus paving the way for modern molecular approaches to treatment of this highly malignant tumor.
hepatocellular carcinoma; hepatitis C virus
Among patients with suspected sepsis, endotoxemia is variably present in association with gram-negative bacteremia. A total of 738 patients with suspected sepsis from 11 studies could be classified into four groups: 131 (18%) patients had both endotoxemia and gram-negative bacteremia (group 1), 87 (12%) had only gram-negative bacteremia (group 2), and 143 (19%) had only endotoxemia (group 3); in 377 (51%) patients neither could be detected (group 4). By the statistical techniques of meta-analysis, the fatality risk for patients with either endotoxemia or gram-negative bacteremia or both was estimated with group-specific case fatality rates from these studies and expressed as an odds ratio (OR; 95% confidence interval [95% CI]) versus patients with these factors absent. This risk was increased marginally when endotoxemia was detected without gram-negative bacteremia (OR, 2.3; 95% CI, 1.3 to 4.0) or the converse (OR, 2.0; 95% CI, 1.0 to 3.8), in contrast to the striking increase when both endotoxemia and gram-negative bacteremia were detected (OR, 6.3; 95% CI, 4.0 to 10.0). Alone, neither endotoxemia nor gram-negative bacteremia is a strong predictor of outcome in patients with suspected sepsis. However, in combination, the two identify a subpopulation with a substantially increased risk of mortality.
Nineteen patients with hip radiographs typical of 'analgesic hip' (rapidly destructive, atrophic arthropathy involving both femoral and acetabular components) have been studied. Women predominated (14:5), and all were elderly (mean age 74 years, range 64-83 years). Destructive hip disease was unilateral in all but one case. The mean interval from symptom onset to typical x ray appearance was short (one year, range three to 24 months), and persistent pain unresponsive to drug therapy was characteristic. Screening showed no metabolic or neurological disease. Contrary to previous reports, non-steroidal anti-inflammatory drugs could not be incriminated in development of the disease. Clinical and radiographic similarity to apatite associated destructive arthritis of other large joints was striking, and occurrence of the latter, uncommon condition in five patients (five shoulders, two knees) suggests that both descriptions represent a common articular response at different joint sites.
Subjective pain score, clinical assessment, 99m technetium joint uptake, infrared thermography, and thermistor skin temperature measurements were evaluated and compared in patients with rheumatoid knee treated with intra-articular hydrocortisone. In 11 patients with definite and classical rheumatoid arthritis, 10 of whom had unilateral knee involvement, the affected knee joints were assessed by the above techniques before and at intervals after treatment of up to 14 days. The anti-inflammatory property of the steroid therapy was shown by all the assessment parameters, values having decreased significantly from the pretreatment values. However, the only parameter still showing a statistically significant decrease on the 14th post-treatment day was 99mTc joint uptake. Correlations were obtained between the two clinical measurements assessed by a physician i.e. pain score and index of joint inflammation. Both of these also correlated with the 99mTc joint uptake but not with skin temperature measurements. Using the clinical assessments as a yardstick, 99mTc joint uptake seemed to provide a useful index of changes in disease activity in the group as a whole. However, skin temperature measurements by infrared thermography and by the thermistor were of considerably less value.