Within-day Changes Research Articles

Changepoint detection on daily home activity pattern: a sliced Poisson process method.

The problem of health and care of people is being revolutionized. An important component of that revolution is disease prevention and health improvement from home. A natural approach to the health problem is monitoring changes in people's behavior or activities. These changes can be indicators of potential health problems. However, due to a person's daily pattern, changes will be observed throughout each day, with, eg, an increase of events around meal times and fewer events during the night. We do not wish to detect such within-day changes but rather changes in the daily behavior pattern from one day to the next. To this end, we assume the set of event times within a given day as a single observation. We model this observation as the realization of an inhomogeneous Poisson process where the rate function can vary with the time of day. Then, we propose to detect changes in the sequence of inhomogeneous Poisson processes. This approach is appropriate for many phenomena, particularly for home activity data. Our methodology is evaluated on simulated data. Overall, our approach uses local change information to detect changes across days. At the same time, it allows us to visualize and interpret the results, changes, and trends over time, allowing the detection of potential health decline.

Daily Diversity Flows: Racial and Ethnic Context Between Home and Work.

The racial and ethnic diversification of the U.S. population has transformed the demographic makeup of communities and rapidly increased exposure to diversity in American neighborhoods. Although diversity exposure occurs throughout people's daily lives, the conventional approach to describing diversity only at places of residence potentially understates the full extent of this phenomenon. In this study, we explore short-term, within-day changes in the diversity of different neighborhoods by considering U.S. workers' work and residential locations. Using estimates for daytime and nighttime populations among metropolitan census tracts, our empirical analyses investigate the extent to which the process of daytime mobility for work relates to changes in the racial and ethnic diversity of different spaces. Our results indicate widespread daily shifts toward diversity for most neighborhood types, especially those with residential (nighttime) populations that are predominantly Black, Latino, or Asian. We find that patterns of intraday diversification experienced minor declines across recent decades but are present in most metropolitan areas. Our findings also show that intraday changes in racial and ethnic diversity overlap with nonracial forms of daily diversity change. Further, average within-day changes in diversity are more pronounced in areas with greater residential segregation.

Getting into flow during virtual meetings: How virtual meetings can benefit employee functioning in the work- and home domain

During the COVID-19 pandemic, a majority of the global workforce turned to virtual meetings for work-related communication and continues to do so as part of the shift to hybrid work. This change in communication patterns has led to an increased scholarly emphasis on the costs of virtual meetings for employees. The present study adds to this emerging field of research by taking a theory-led approach to highlight that alongside costs there are benefits to spending time in virtual meetings for employee functioning. Specifically, we integrate the concept of flow experiences and the Conservation of Resources theory to expand our understanding of the psychological mechanisms that link daily time spent in virtual meetings to employees' functioning in the work (i.e., task performance and counterproductive work behavior) and home domains (i.e., work-family conflict and need for recovery). More specifically, we argue that the benefits of virtual meetings manifest through flow experiences and associated reduced within-day changes in cognitive depletion. Furthermore, we identify low emotional dissonance as a contingency in virtual meetings that can strengthen the benefits of this mode of computer mediated communication. Results from two daily diary studies largely support the hypothesized relationships. Our findings have important theoretical and practical implications for employee functioning in the ‘new normal’ of hybrid work.

Within-day changes in luminal, stromal choroidal thickness, and choroidal vascularity index in healthy adults.

To investigate topographical and within-day changes in the choroidal vascularity index and its association with choroidal thickness parameters (total, luminal, and stromal thickness) among young adults. : Choroidal thickness and vascularity index were measured in 28 healthy young adults (age mean ± standard deviation [SD]: 25 ± 3.0) using spectral-domain optical coherence tomography. Participants were divided into three refractive groups: emmetropes, myopes, and high myopes. Choroidal parameters were evaluated in the macular and peripheral regions in the superior and inferior regions at two time points during the day; in the morning (at 7 am) and in the afternoon (at 1 pm). : All investigated choroidal thickness parameters showed a significant topographical variation across the vertical meridian, between the foveal (270 ± 89 μm, 170 ± 45 μm, and 111 ± 47 μm, respectively) and peripheral (246 ± 68 μm, 160 ± 39 μm, 86 ± 36 μm, respectively). The superior choroid was thicker in all thickness parameters compared to the inferior choroid. A significant increase in the vascularity percentage was seen from the fovea (61.8 ± 7%) toward the periphery (66.4 ± 7%). Thinner choroidal parameters were associated with high myopia, whereas an increase in the vascularity index was observed in high myopes. Significant within-day changes were observed in all choroidal thickness parameters, which were slightly reduced in the afternoon. The choroidal vascularity index (CVI) increased from 61.3 ± 5.3% in the morning and 63.2 ± 5.8% in the afternoon. High myopes exhibited reduced within-day amplitude in stromal thickness. : All parameters showed significant regional variations. Myopia is associated with greater thinning in stromal thickness rather than vascular thickness. Only high myopes experienced reduced within-day change amplitudes in stromal choroidal thickness that was more predominant in the foveal and parafoveal regions.

Leader-Follower Emotional Entrainment and Daily Interaction Quality: The Role of Follower Attachment

Followers’ high-quality interactions with their leader are a cornerstone of leadership research. Despite a growing understanding of leader emotions as static predictors of high-quality leader-follower relationships, research has yet to pay attention to the micro-level, dynamic interplay of leader and follower emotions for the emergence of daily interaction quality. We develop an episodic emotional entrainment perspective stating that leaders’ expressions of positive (joy, calmness) and negative emotions (fear, sadness) serve as affective events influencing corresponding follower emotions. Over the course of a day, this manifests in affective entrainment patterns (i.e., the leaders’ and followers’ affective states fluctuating in a common rhythm), which in turn predict followers’ perceived interaction quality with their leaders. The strength of the entrainment process, however, is influenced by the follower’s attachment style. We conducted a daily diary study across ten workdays with four measurements each day (N=72 employees; N=497 daily responses). Results of within-day multilevel latent growth models support an emotional entrainment process such that followers’ felt emotions oscillated with the observed leader emotional expression over the course of the day. Within-day changes in followers’ felt high-activated emotions (i.e., joy, fear) predicted perceived end-of-day interaction quality, whereas changes in low-activated emotions (i.e., calmness, sadness) did not. The relationship between leaders’ expressions of joy (fear) and corresponding follower felt emotions at the end of the day via emotional entrainment was weaker (stronger) for followers with high attachment avoidance (attachment anxiety), which in turn was positively (negatively) associated with end-of-day interaction quality.

Selection, Optimization, and Compensation Strategies and Within-Day Changes in Occupational Well-Being

According to the selection, optimization, compensation (SOC) model, employees can actively influence their well-being. However, associations could differ at the within- and between-person levels. Considering SOC strategies as dynamic processes that unfold during a workday, we hypothesized that selection-focused strategies are related to decreased work fatigue, whereas pursuit-focused strategies are related to increased work fatigue at the end of the work day. We further hypothesized that preference-based strategies are related to increased job satisfaction, whereas loss-based strategies are related to decreased job satisfaction at the end of a workday. We tested these hypotheses with a sample of 244 employees who completed twice-daily measurements over ten consecutive work days. Day-level results of multi-level analyses showed that, controlling for morning levels of workload and autonomy, loss-based selection was positively related to changes in work fatigue. Optimization and compensation were positively related to changes in job satisfaction, whereas loss-based selection was negatively related to changes in job satisfaction. At the person-level, loss-based selection was associated with higher work fatigue, and optimization with higher job satisfaction. In supplemental analyses, we found little evidence for reversed relationships. Results suggest that links exist between SOC strategies and within-day changes in occupational well-being, yet the direction of effects differs between strategies.

Mastitis detection with recurrent neural networks in farms using automated milking systems

Mastitis is the most important disease in the dairy industry. With widespread adoption of automated milking systems (AMS) in Canada, there is an increasing need for automated detection of mastitis in AMS farms. The main objective of this study was to develop a recurrent neural network (RNN) model for the detection of clinical mastitis (CM) in dairy cows on farms using AMS. Producer-recorded treatment records and AMS data were collected over 3 time periods from a total of 89 dairy farms in 7 provinces across Canada. In addition to developing effective models for the detection of CM, our study also evaluated different windows around the day of diagnosis when the cow would be considered CM-positive to guide practical implementation of models. We also compared numerous subsets of variables including milk and behavioural characteristics, cow traits and farm-level/environmental variables to determine their importance and impact on model performance. Data were randomly divided into a training and a hold-out test set, consisting of all records from 66 and 23 farms, respectively. A 10-fold internal cross-validation was also employed on the training set for model development. When comparing different windows of time around diagnosis, considering animals as CM-positive for 3 d prior to recorded diagnosis resulted in the most timely and effective detection of CM with a per-case sensitivity of 89.8% (range: 83.3–96.0%), and per-day specificity of 84.3% (range: 83.4–85.8%) over the validation folds. These levels of sensitivity and specificity were achieved when using all recorded variables and their daily variances, although the inclusion of behavioural variables and farm-level/environmental variables provided marginal performance improvement over using milk traits alone. Performance of the model was worse on the hold-out test set with a per-case sensitivity of 83.5% (range: 77.9–86.3%) and a per-day specificity of 80.4 % (range: 78.1–82.4%), likely due to farm-specific heterogeneity not encountered in the training data. Over 90% of cases of severe CM (defined by an increase in milk temperature over the pre-CM baseline) were identified by the model, indicating effective performance for the detection of CM requiring the most immediate treatment. Somatic cell count, daily variance in milking interval and milk temperature were identified as the 3 most important variables defined by their impact on model predictions. In addition to milking traits, 8 of the top 20 variables were behavioural measurements, suggesting they can play a role in the detection of CM. Daily variances also represented 8 of the 20 most important variables indicating that CM onset may be associated with sudden, within-day changes in the animal. In conclusion, this study demonstrates that RNNs are able to effectively detect CM by integrating a number of variables that are regularly measured on AMS farms but have typically been excluded from CM detection models.

Negative Emotion Differentiation Attenuates the Within-Person Indirect Effect of Daily Stress on Nightly Sleep Quality Through Calmness.

The ability to differentiate between negative emotional states [negative emotion differentiation (NED)] has been conceptualized as a trait that facilitates effective emotion regulation and buffers stress reactivity. In the present research, we investigated the role of NED in within-person processes of daily affect regulation and coping during times of stress (the first COVID-19-related pandemic lockdown in April 2020). Using intensive longitudinal data, we analyzed whether daily stress had an indirect effect on sleep quality through calmness in the evening, and we tested whether NED moderated this within-person indirect effect by buffering the link between daily stress and calmness in the evening. A non-representative community sample (n = 313, 15–82 years old) participated in a 21-day ambulatory assessment with twice-daily surveys. The results of multilevel mediation models showed that higher daily stress was related to within-day change in calmness from morning to evening, resulting in less calmness in the evening within persons. Less calmness in the evening, in turn, was related to poorer nightly sleep quality within persons. As expected, higher NED predicted a less negative within-person link between daily stress and calmness in the evening, thereby attenuating the indirect effect of daily stress on nightly sleep quality through calmness. This effect held when we controlled for mean negative emotions and depression. The results provide support for a diathesis-stress model of NED, and hence, for NED as a protective factor that helps to explain why some individuals remain more resilient during times of stress than others.

Effects of Proactive Behavior on Within-Day Changes in Occupational Well-Being: the Role of Organizational Tenure and Emotion Regulation Skills

Research has recently started to examine relationships between proactive behavior and employee well-being. Investigating these relationships is important to understand the effects of proactive behavior at work, and whether proactive behavior leads to an increase or a decrease in well-being. In this daily-diary study, we investigated effects of proactive behavior on within-day changes in four indicators of occupational well-being (i.e., activated positive and negative affect, emotional work engagement and fatigue). Moreover, based on the meta-concept of wise proactivity, which suggests that proactive behavior may lead to either favorable or unfavorable consequences depending on certain boundary conditions, we examined organizational tenure and emotion regulation skills as moderators of these effects. In total, N = 71 employees participated in a daily-diary study with two measurements per day for ten consecutive working days. Results showed that emotion regulation skills interacted with proactive behavior to predict within-day changes in emotional work fatigue, such that the effect of proactive behavior on emotional work fatigue was only positive for employees with low (vs. high) emotion regulation skills. Supplementary analyses examining reverse effects of occupational well-being on proactive behavior showed that organizational tenure interacted with activated positive and negative affect in predicting within-day changes in proactive behavior. For employees with lower (vs. higher) organizational tenure, both activated positive and negative affect were negatively associated with proactive behavior. Overall, our findings contribute to the growing body of research on proactive behavior and well-being by demonstrating reciprocal and conditional day-level relationships among these variables.

Evaluating sociometer theory in children’s everyday lives: Inclusion, but not exclusion by peers at school is related to within-day change in self-esteem

Sociometer theory proposes that a person’s self-esteem is a permanent monitor of perceived social inclusion and exclusion in a given situation. Despite this within-person perspective, respective research in children’s everyday lives is lacking. In three intensive longitudinal studies, we examined whether children’s self-esteem was associated with social inclusion and exclusion by peers at school. Based on sociometer theory, we expected social inclusion to positively predict self-esteem and social exclusion to negatively predict self-esteem on within- and between-person levels. Children aged 9–12 years reported state self-esteem twice per day (morning and evening) and social inclusion and exclusion once per day for two (Study 1) and four weeks (Studies 2–3). Consistently across studies, we found that social inclusion positively predicted evening self-esteem on within- and between-person levels. By contrast, social exclusion was not associated with evening self-esteem on the within-person level. On the between-person level, social exclusion was negatively linked to evening self-esteem only in Study 1. Multilevel latent change score models revealed that children’s self-esteem changed from mornings (before school) to evenings (after school) depending on their perceived daily social inclusion, but not exclusion. The findings are discussed in light of sociometer theory and the bad-is-stronger-than-good phenomenon.

P60 Daily fluctuations in fatigue severity and C-reactive protein in people with rheumatic diseases

Abstract Background Fluctuations in fatigue severity are common in people with inflammatory (e.g. rheumatoid arthritis (RA)) and non-inflammatory (e.g. fibromyalgia (FM) and osteoarthritis (OA)) rheumatic diseases. We tested whether fluctuations in fatigue in RA, OA and FM were explained by fluctuations in inflammation (C-reactive protein (CRP)), pain and mood. Methods Participants in the GIRAF (Gaining Insight into RheumAtic Fatigue) study used a patient co-configured app to report fatigue severity, pain severity and mood on a 5-point ordinal scale (increasing scores = worse state) twice daily for 7 days. Daily CRP (mg/L) was measured via dried blood spot sampling. Fluctuations in fatigue were calculated as within-day (morning to evening variability) and between-days (morning to morning; evening to evening variability). Multi-level mixed effects ordered logistic regression models tested the relationship between fluctuations in CRP and fatigue over 7 days. The relationships between fluctuations in fatigue, pain and mood were also examined. Models were adjusted for age, sex and disease diagnosis. Results Thirty-eight people (RA:12, OA:13, FM:13) participated and contributed data on 190 (71% of eligible) days. Participants were mostly female (81.6%), with a median age of 56 years. There were no demographic differences between disease groups. Within-day changes in fatigue severity of ≥one point were observed on 97 (51.1%) days and between-days changes were observed on 52% of mornings (92/177 eligible periods) and 49.4% of evenings (85/172 eligible). Fluctuations in pain severity and mood of ≥one point were similarly common (data not shown). Median CRP levels were low (<5mg/L) across all diseases and did not fluctuate substantially between days (change ≥1mg/L:17.5% (33/189) of days). 8 participants (21.1%: RA:4, OA:2, FM:2) had “active inflammation” (CRP>5mg/L) on a total 22 (8.3%) days in the study (range:1-8 days). Fluctuations in CRP were not associated with fluctuations in fatigue (odds-ratio:1.01, 95%CI:0.83-1.22). Fluctuations in pain severity (6.93, 4.68-10.28) and mood (4.58, 3.26-6.45) were associated with fluctuations in fatigue (Table 1). Conclusion Fluctuations in fatigue severity were common in people with rheumatic diseases. Inflammation was low and did not predict fatigue variability. Optimal management should target fatigue independently of inflammatory disease management and may benefit from modification of pain and mood. Disclosures K.L. Druce None. D.S. Gibson None. K. McEleney None. S. Meleck None. B. James None. B. Hellman None. W.G. Dixon None. J. Mcbeth None.

Monitoring colony phenology using within-day variability in continuous weight and temperature of honey bee hives

Continuous weight and temperature data were collected for honey bee hives in two locations in Arizona, and those data were evaluated with respect to separate measurements of hive phenology to develop methods for noninvasive hive monitoring. Weight and temperature data were divided into the 25-h running average and the daily within-day changes, or “detrended” data. Data on adult bee and brood masses from hive evaluations were regressed on the amplitudes of sine curves fit to the detrended data. Weight data amplitudes were significantly correlated with adult bee populations during nectar flows, and temperature amplitudes were found inversely correlated with the log of colony brood weight. The relationships were validated using independent datasets. In addition, the effects of an adult bee kill on hive weight data were contrasted with published data on weight changes during swarming. Continuous data were found to be rich sources of information about colony health and activity.

Design of a smartphone application to monitor stress, asthma symptoms, and asthma inhaler use

Design of a smartphone application to monitor stress, asthma symptoms, and asthma inhaler use

Within-day variability of particulate organic carbon and remote-sensing reflectance during a bloom of Phaeocystis antarctica in the Ross Sea, Antarctica

We examined the within-day variability in seawater optical properties and biogeochemical constituents for a high-latitude location in the Ross Sea, Antarctica, during development of the annual spring phytoplankton bloom. Measurements of particulate organic carbon concentration (POC), chlorophyll-a concentration (Chl), and particle size distribution were conducted at 4–6 hour intervals in parallel with determinations of the spectral absorption and attenuation coefficients of particles, and the spectral remote-sensing reflectance of the surface ocean (Rrs). Surface POC and Chl exhibited more than a twofold variation throughout the day in the continuous presence of natural light. A minimum occurred near local noon coinciding with peak solar irradiance, a maximum in the evening, and a subsequent decrease throughout the night-time hours. These patterns were accompanied by large changes in the magnitude and spectral shape of Rrs, including the blue-to-green spectral band ratios used in ocean colour algorithms for estimating POC and Chl. The variability in Rrs could not be explained by changes in solar zenith angle, but was consistent with observations of within-day variations in spectral absorption and scattering by particles which were influenced by changes in the particle concentration and size distribution. The accuracy of an empirical ocean colour algorithm for estimating POC from Rrs was unaffected by within-day variability, implying that short-term variations in surface POC can be potentially monitored by multiple within-day measurements of Rrs, through means of in situ and remote sensing observations if available. Our findings also suggest that within-day changes in POC can be significant compared with the variability observed on meso-scale spatial scales, potentially confounding the interpretation of remote-sensing data obtained from temporal and spatial compositing of images measured at different times within a single day.

Unstimulated cortisol secretory activity in everyday life and its relationship with fatigue and chronic fatigue syndrome: A systematic review and subset meta-analysis

The hypothalamic-pituitary-adrenal (HPA) axis is a psychoneuroendocrine regulator of the stress response and immune system, and dysfunctions have been associated with outcomes in several physical health conditions. Its end product, cortisol, is relevant to fatigue due to its role in energy metabolism. The systematic review examined the relationship between different markers of unstimulated salivary cortisol activity in everyday life in chronic fatigue syndrome (CFS) and fatigue assessed in other clinical and general populations. Search terms for the review related to salivary cortisol assessments, everyday life contexts, and fatigue. All eligible studies (n=19) were reviewed narratively in terms of associations between fatigue and assessed cortisol markers, including the cortisol awakening response (CAR), circadian profile (CP) output, and diurnal cortisol slope (DCS). Subset meta-analyses were conducted of case-control CFS studies examining group differences in three cortisol outcomes: CAR output; CAR increase; and CP output. Meta-analyses revealed an attenuation of the CAR increase within CFS compared to controls (d=-.34) but no statistically significant differences between groups for other markers. In the narrative review, total cortisol output (CAR or CP) was rarely associated with fatigue in any population; CAR increase and DCS were most relevant. Outcomes reflecting within-day change in cortisol levels (CAR increase; DCS) may be the most relevant to fatigue experience, and future research in this area should report at least one such marker. Results should be considered with caution due to heterogeneity in one meta-analysis and the small number of studies.

The Influence of Energetic Condition on Flight Initiation and Orientation of Migratory Songbirds in the Gulf of Maine Region

ABSTRACT. Energetic condition influences migratory decisions made by songbirds. Over-water or coastal flights are often the shortest routes but may be dangerous for landbirds because they may get caught over water where they are not able to rest and refuel. We investigated how various components of energetic condition were related to the likelihood that a migrant songbird in the Gulf of Maine region would initiate a migratory flight and the direction that it would choose. We used release tests and measurements of energy stores (fat score), plasma triglycerides, and within-day changes in body mass to investigate whether these measures of condition were related to the decisions migrants must make about when to resume migration and which direction they should go. Our results indicated that the amount of fat that a bird had at the time of release influenced the decision to initiate a flight, whereas directional decisions were influenced by both fat and within-day changes in body mass. Plasma triglyceride leve...

Diurnal variation of connective tissue metabolites in early and long-standing rheumatoid arthritis and in healthy individuals

Objective:To study the circadian variability of circulating connective tissue metabolites in patients with very early (VERA) and long-standing rheumatoid arthritis (LRA) and in healthy control individuals.Methods:Eleven patients with newly diagnosed, untreated RA, disease duration < 6 months, and 10 patients with LRA were included, together with 16 healthy control subjects. Seven blood samples were drawn serially from each participant at 3-hourly intervals from 10.00–22.00 h, fasting at 07.00 h the following day and finally at 10.00 h. Cartilage oligomeric matrix protein (COMP) and hyaluronan (HYA) were quantified by enzyme-linked immunosorbent assay (ELISA) and the N-terminal propeptide of collagen type III (PIIINP) was determined by radioimmunoassay (RIA).Results: The two RA subsets did not differ with respect to age, gender distribution, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), immunoglobulin M rheumatoid factor (IgM-RF) status, global health status and pain. Healthy controls were younger than both VERA and LRA patients. At baseline, PIIINP, HYA, and COMP were increased significantly in both RA cohorts compared with controls. No circadian rhythmicity was recorded with respect to HYA and PIIINP. By contrast, COMP was decreased at 07.00 h in all three study groups; this decline was particularly prominent in LRA.Conclusion:Within-day changes of PIIINP, HYA, and COMP are qualitatively similar in RA at different stages and in healthy individuals, indicating that the connective tissue responses to rhythmic physiological signals are not abolished by disease-modifying anti-rheumatic drug (DMARD) therapy. Serum for measurement of HYA and COMP should be collected between 10.00 and 20.00 h.

Incentives and the Allocation of Effort Over Time: The Joint Role of Affective and Cognitive Decision Making

We use natural experiments – plausibly exogenous, anticipated increases in the piece rate – to study how effort responds to incentives. Our first finding, like some previous studies, lends little support to the view that incentives increase effort: raising the piece rate has zero effect on total daily effort. Previous studies have speculated that changes in motivation over the course of the workday, caused by the increase in the piece rate, may lead to this result, but have relied on data aggregated to the day. Our data allow us to look within the workday. We find that workers do respond to incentives within the day: they work significantly harder in early hours of work, but significantly less hard later on, with a net effect of zero on total daily effort. We consider different possible explanations for this behavior. The most parsimonious explanation is a model in the spirit of Loewenstein and O'Donoghue (2005), in which a cognitive system, assumed to behave like the standard economic model predicts, is in conflict with the affective system. We review evidence from psychology and neuroscience to argue that the affective system may be strongly influenced by within-day changes in earnings, relative to an earnings goal. The affective system cares less about income once the goal is surpassed, providing an explanation for a drop in effort later in the day, and for the findings of earlier studies.

Effects Lasting into Adolescence of Exposure to Betamimetics In Utero

The range of the predictable within-day change in blood pressure, assessed as the circadian blood pressure amplitude, is greater in newborns who have been exposed in utero to betamimetics than in those not exposed. A larger circadian blood pressure amplitude is also found in infants and children with a positive versus those with a negative family history of high blood pressure. In adulthood, an excessive circadian blood pressure amplitude is associated with a 6-fold increase in risk of ischaemic stroke. To determine whether the large circadian blood pressure amplitude associated with intrauterine exposure to betamimetics in newborns persists later in life, the progeny of mothers who had had similar obstetric situations but had been treated either with spasmolytics (not including betamimetics) or with betamimetics to prevent premature labour was assessed. The blood pressure of 43 adolescents aged between 11 and 14 years was measured at 15-minute intervals for 2 days with an ambulatory monitor; an echocardiogram was also taken. A multiple regression analysis accounting for gender- and age-related changes revealed a dose-dependent effect of betamimetic exposure on the circadian blood pressure amplitude of the offspring. Exposed children also tended to have a larger left ventricular mass index. Thus, in utero exposure to betamimetic drugs may have cardiovascular effects lasting into adolescence.

Reference Values for Orcadian Rhythms of 98 Variables in Clinically Healthy Men in the Fifth Decade of Life

Nine clinically healthy men, 41-47 yr of age, served as subjects in a 24-hr study conducted at the Edward Hines Jr Veterans Administration Hospital in the Chicago area in May 1988. Physiologic measurements, and blood and urine samples were collected at 3-hr intervals over a single 24-hr period beginning at 1900. The number of variables measured or calculated (total = 98) included: 6 vital signs (oral temperature, pulse, blood- and intraocular pressures); 16 in whole blood (counts and differentials); 50 in serum (SMAC-24, lipids, hormones, electrophoresis of LDH and proteins); and 26 in urine (solids, proteins, creatinine, catecholamines, melatonin, cortisol, electrolytes and metals). Data were analyzed for time effect by analysis of variance (ANOVA) and for circadian rhythm by single cosinor. Individual rhythm characteristics for each variable were summarized for the group by population mean cosinor. The vast majority of variables revealed statistically significant within-day changes in values as validated by one-way ANOVA. All vital signs (except for intraocular pressures) and all serum hormones displayed a prominent circadian rhythm for the group, as did most variables in whole blood, while only about half of the variables in urine demonstrated a significant group rhythm. The results obtained are meant to: (a) document the circadian time structure; and (b) serve as reference values for circadian rhythm characteristics (range of change, mesor, amplitude and acrophase) for a defined group of individuals: clinically-healthy adult men in the prime of life.