Prospective associations of technostress at work, burnout symptoms, hair cortisol, and chronic low-grade inflammation

BACKGROUND

Working conditions in the age of digitalization harbor risks for chronic stress and burnout. However, real-world investigations into biological effects of technostress, that is stress in the context of digital technology use, are sparse. This study prospectively assessed associations between technostress, general work stress, burnout symptoms, hair cortisol, and chronic low-grade inflammation.

METHODS

Hospital employees (N = 238, 182 females, Mage = 28.5 years) participated in a prospective cohort study with two follow-ups six months apart (T2, T3). Participants answered standardized questionnaires on general job strain (job demand-control ratio), technostressors (work interruptions, multitasking, information overload), burnout symptoms (exhaustion, mental distance), and relevant confounders. Moreover, they provided capillary blood samples for C-reactive protein (CRP) and hair strands for hair cortisol concentration (HCC) analysis. Structural equation modelling was performed.

RESULTS

The factorial structure of survey measures was confirmed. Burnout symptoms (MT2 = 2.17, MT3 = 2.33) and HCC (MT2 = 4.79, MT3 = 9.56; pg/mg) increased over time, CRP did not (MT2 = 1.15, MT3 = 1.21; mg/L). Adjusted path models showed that technostress was negatively associated with HCC (β = -0.16, p =.003), but not with burnout and CRP. General work stress in contrast, was not significantly associated with burnout, HCC or CRP. Furthermore, there were reciprocal effects of CRP on HCC (β = 0.28, p =.001) and of HCC on CRP (β = -0.10, p ≤.001). Associations were robust in additional analyses including further confounders.

CONCLUSION

This is the first study on prospective effects of technostress on employees' endocrine and inflammatory systems. Results suggest differential effects of technostress on the hypothalamic-pituitary-adrenocortical axis activity. Given its key role for long-term health, the findings have important implications for occupational health and safety in digitalized work environments.

People do change their beliefs about conspiracy theories-but not often

Recent research has produced a significant body of knowledge about the antecedents and consequences of individual differences in belief in conspiracy theories. What is less clear, however, is the extent to which individuals' beliefs in conspiracy theories vary over time (i.e., within-person variation). In this descriptive and exploratory study, we therefore aimed to describe within-person variability in belief in conspiracy theories. We collected data from 498 Australians and New Zealanders using an online longitudinal survey, with data collected at monthly intervals over 6 months (March to September 2021). Our measure of conspiracy theories included items describing ten conspiracy theories with responses on a 5-point Likert scale. While there was substantial between-person variance, there was much less within-person variance (intraclass r = 0.91). This suggests that beliefs in conspiracy theories were highly stable in our sample. This stability implies that longitudinal studies testing hypotheses about the causes and consequences of belief in conspiracy theories may require large samples of participants and time points to achieve adequate power. It also implies that explanations of belief in conspiracy theories need to accommodate the observation that beliefs in such theories vary much more between people than within people.

Examination of the temporal sequence between social media use and well-being in a representative sample of adults

Given insufficient prospective evidence for relationships between social media use and well-being among adults, the present study examined the temporal sequence between social media use and psychological distress and life satisfaction, and explored age and gender differences. A representative sample of adults (N = 7331; 62.4% women; Mage = 51.94; SD = 13.48; 15-94 years) were surveyed annually across four waves. Cross-lagged panel models demonstrated bidirectional relationships between social media use and well-being. Higher psychological distress and lower life satisfaction predicted higher social media use more strongly than the reverse direction, with effects particularly pronounced for the impact of psychological distress. Although the patterns of findings were relatively consistent across age and gender, results suggested that women and middle- and older-aged adults experience detrimental effects of social media use on well-being, which may drive subsequent increased use of social media. The bidirectional relationships suggest that adults who experience psychological distress or lower life satisfaction may seek to use social media as a way to alleviate poor well-being. However, paradoxically, this maladaptive coping mechanism appears to drive increased social media use which in turn can exacerbate poor well-being. Clinicians should be aware of these bidirectional relationships and work with clients towards replacing ineffective strategies with more helpful coping approaches. As this study used a simplistic measure of social media use, future research should address this limitation and explore nuanced relationships afforded by assessing specific social media activities or exposure to certain types of content.

Understanding the factors that influence communication about COVID-19 vaccines with patients: Perspectives of Australian immunisation providers

Background

COVID-19 immunisation providers have been at the forefront of the pandemic, and their ability to communicate effectively with patients is key to encouraging COVID-19 vaccine acceptance and uptake. This study explored providers' perspectives on the factors influencing communication with patients about COVID-19 vaccines.

Methods

We used an explanatory-sequential mixed-methods approach to conduct the study between December 2021 and March 2022. Phase I involved a cross-sectional survey with immunisation providers in New South Wales (n = 341; 189 general practitioners, 118 nurses and 34 pharmacists), followed by Phase II: semi-structured, in-depth qualitative interviews (n = 19; 10 nurses, 9 pharmacists). We generated descriptive results for the survey. We analysed the qualitative data thematically using an inductive approach.

Results

Almost half of survey participants reported communicating often with people who were hesitant about COVID-19 vaccines (49 %; 166/341), however, 21 % (71/341) reported inadequate time to address concerns during consultations. Interview participants reported communication challenges, including time constraints, difficulties addressing and eliciting patient concerns, and keeping up to date with changing information. Conversely, interview participants reported that easy access to government information resources, time to learn about COVID-19 vaccines proactively, knowing about and being able to use tailored strategies to support Aboriginal and Torres Strait Islander and CALD patients were helpful when communicating with patients.

Conclusions

Immunisation providers play an important role in patient vaccine acceptance and uptake. Our findings indicate that whilst providers were largely confident in their interactions with patients, further communication support would strengthen providers' skills in communicating with patients who have questions and concerns about COVID-19 vaccines.

Testing persuasive messages about booster doses of COVID-19 vaccines on intention to vaccinate in Australian adults: A randomised controlled trial

INTRODUCTION

Achieving high COVID-19 vaccine booster coverage is an ongoing global challenge. Health authorities need evidence about effective communication interventions to improve acceptance and uptake. This study aimed to test effects of persuasive messages about COVID-19 vaccine booster doses on intention to vaccinate amongst eligible adults in Australia.

METHODS

In this online randomised controlled trial, adult participants received one of four intervention messages or a control message. The control message provided information about booster dose eligibility. Intervention messages added to the control message, each using a different persuasive strategy, including: emphasising personal health benefits of booster doses, community health benefits, non-health benefits, and personal agency in choosing vaccination. After the intervention, participants answered items about COVID-19 booster vaccine intention and beliefs. Intervention groups were compared to the control using tests of two proportions; differences of ≥5 percentage points were deemed clinically significant. A sub-group analysis was conducted among hesitant participants.

RESULTS

Of the 487 consenting and randomised participants, 442 (90.8%) completed the experiment and were included in the analysis. Participants viewing messages emphasising non-health benefits had the highest intention compared to those who viewed the control message (percentage point diff: 9.0, 95% CI -0.8, 18.8, p = 0.071). Intention was even higher among hesitant individuals in this intervention group compared to the control group (percentage point diff: 15.6, 95% CI -6.0, 37.3, p = 0.150). Conversely, intention was lower among hesitant individuals who viewed messages emphasising personal agency compared to the control group (percentage point diff: -10.8, 95% CI -33.0, 11.4, p = 0.330), although evidence in support of these findings is weak.

CONCLUSION

Health authorities should highlight non-health benefits to encourage COVID-19 vaccine booster uptake but use messages emphasising personal agency with caution. These findings can inform communication message development and strategies to improve COVID-19 vaccine booster uptake. Clinical trial registration: Registered with the Australian New Zealand Clinical Trials Registry (ACTRN12622001404718); trial webpage: https://www.anzctr.org.au/ACTRN12622001404718.aspx.

Effect of persuasive messaging about COVID-19 vaccines for 5- to 11-year-old children on parent intention to vaccinate

AIM

Uptake of COVID-19 vaccines for children aged 5-11 years old in Australia has plateaued. Persuasive messaging is an efficient and adaptable potential intervention to promote vaccine uptake, but evidence for its effectiveness is varied and dependent on context and cultural values. This study aimed to test persuasive messages to promote COVID-19 vaccines for children in Australia.

METHODS

A parallel, online, randomised control experiment was conducted between 14 and 21 January 2022. Participants were Australian parents of a child aged 5-11 years who had not vaccinated their child with a COVID-19 vaccine. After providing demographic details and level of vaccine hesitancy, parents viewed either the control message or one of four intervention texts emphasising (i) personal health benefits; (ii) community health benefits; (iii) non-health benefits; or (iv) personal agency. The primary outcome was parents' intention to vaccinate their child.

RESULTS

The analysis included 463 participants, of whom 58.7% (272/463) were hesitant about COVID-19 vaccines for children. Intention to vaccinate was higher in the community health (7.8%, 95% confidence interval (CI) -5.3% to 21.0%) and non-health (6.9%, 95% CI -6.4% to 20.3%) groups, and lower in the personal agency group (-3.9, 95% CI -17.7 to 9.9) compared to control, but these differences did not reach statistical significance. The effects of the messages among hesitant parents were similar to the overall study population.

CONCLUSION

Short, text-based messages alone are unlikely to influence parental intention to vaccinate their child with the COVID-19 vaccine. Multiple strategies tailored for the target audience should also be utilised.

Increased belief in vaccination conspiracy theories predicts increases in vaccination hesitancy and powerlessness: Results from a longitudinal study

RATIONALE

Vaccinations are an important part of a public health strategy against preventable diseases, and uptake is influenced by factors including hesitancy. The belief of vaccine related misinformation including anti-vaccination conspiracy theories has been found to be associated with increased vaccine hesitancy.

OBJECTIVE

While research suggests that these conspiracy theory beliefs may arise to satisfy unmet needs such as restoring loss of personal control, somewhat ironically these anti-vaccination conspiracy theories may frustrate these needs. This study examined the causal relationships between vaccination hesitancy, vaccination conspiracy theories, and vaccination related powerlessness.

METHODS

Using a stationary random intercepts cross lagged panel model, we investigated the temporal ordering of vaccination hesitancy, powerlessness, and vaccination conspiracy theory beliefs in a sample of Australian adults (N = 500) in a longitudinal study with 5-timepoints over 4-months between June and October 2021.

RESULTS

Results from a random intercept cross-lagged model, that separates between-person stability from within-person change, suggested that increased belief in vaccination conspiracy theories was associated with future increases in vaccination hesitancy and powerlessness (but not vice versa). Findings also showed that increases in vaccination hesitancy and conspiracy theory beliefs predicted respective increases from a person's trait-level mean at subsequent timepoints.

CONCLUSIONS

Vaccination conspiracy theories appear to increase vaccination powerlessness and hesitancy, rather than satisfying an unmet need for personal control.

Shining a spotlight on the dangerous consequences of conspiracy theories

The COVID-19 pandemic has illuminated how conspiracy beliefs–that explain important events as the secret actions of the powerful–can severely impact health choices (such as reduced infection-prevention behaviours). However, the consequences of conspiracy beliefs span far beyond the topic of COVID-19. This review shines a spotlight on how conspiracy beliefs could impact public and personal health (e.g., vaccine uptake), democratic citizenship (e.g., political engagement), intergroup relations (e.g., prejudice and discrimination), and may inspire violence and extremism. We argue that conspiracy beliefs are likely to have the power to mobilise citizens in ways detrimental to a smooth-running society. We conclude the review by offering a range of fruitful avenues for future investigation.

A prospective examination of relationships between social media use and body dissatisfaction in a representative sample of adults

This study examined the temporal sequence of the relationship between social media use and body dissatisfaction in adults. A representative sample of adults (19-92 years old; M = 52.83, SD = 13.43; 62.02% women, 37.98% men) completed measures of social media use, body dissatisfaction, age, gender, BMI, and demographic variables in 2015, 2016, 2017, 2018 and 2019 (N = 6258) in the New Zealand Attitudes and Values Study. In the full sample, higher social media use was significantly associated with higher body dissatisfaction one year later, as was higher body dissatisfaction with higher social media use one year later after controlling for body dissatisfaction/social media use (T-1), gender, age, BMI, ethnicity, relationships status, and SES. Effects were small. The prospective pathway from social media use to body dissatisfaction was significant in all age groups but the reverse relationship was only significant in the middle aged and older groups. Both pathway directions were significant in women but only the pathway from body dissatisfaction to social media use was significant in men. The research has limitations and replication is required. However, findings suggest raising awareness about how to use social media positively across the broad community, not merely in adolescents, may be worthwhile.

Why are beliefs in different conspiracy theories positively correlated across individuals? Testing monological network versus unidimensional factor model explanations

A substantial minority of the public express belief in conspiracy theories. A robust phenomenon in this area is that people who believe one conspiracy theory are more likely to believe in others. But the reason for this "positive manifold" of belief in conspiracy theories is unclear. One possibility is that a single underlying latent factor (e.g. "conspiracism") causes variation in belief in specific conspiracy theories. Another possibility is that beliefs in various conspiracy theories support one another in a mutually reinforcing network of beliefs (the "monological belief system" theory). While the monological theory has been influential in the literature, the fact that it can be operationalised as a statistical network model has not previously been recognised. In this study, we therefore tested both the unidimensional factor model and a network model. Participants were 1553 American adults recruited via Prolific. Belief in conspiracies was measured using an adapted version of the Belief in Conspiracy Theories Inventory. The fit of the two competing models was evaluated both by using van Bork et al.'s (Psychometrika, 83, 2018, 443, Multivariate Behavioral Research, 56, 2019, 175) method for testing network versus unidimensional factor models, as well as by evaluating goodness of fit to the sample covariance matrix. In both cases, evaluation of fit according to our pre-registered inferential criteria favoured the network model.

The impact of completing body image assessments on adolescents' body image and engagement in body change strategies: Harmful or harmless?

Parents and educators have raised concerns that participating in body image research may cause or increase poor body image and engagement in body change strategies. This quasi-experimental study compared body image and body change strategy outcomes among adolescents who had, and had not, previously been exposed to the same assessment questions 6-months prior (twice- vs once-completers). Comparison was also made between groups who completed an assessment containing only positively worded items or both positive and negative items (positive vs mixed valence). Boys and girls (N = 1,532, M_age = 13.83, SD = 1.18) completed online measures of body dissatisfaction, body appreciation, overvaluation of weight and shape, appearance esteem, and body change strategies. In regression analyses, neither body image nor body change strategies were predicted by group (completion or valence groups), except lower body dissatisfaction and higher body appreciation among twice-completers. Most participants did not experience individual-level change in body image or body change strategies over 6-months. Findings suggest that body image assessments may not put adolescents at risk of poor body image or engagement with body change strategies, however; experimental research is needed. Some improvement in body image may have implications for prospective and prevention research.

Addressing Myths and Vaccine Hesitancy: A Randomized Trial

OBJECTIVES

Evidence on repeating vaccination misinformation or "myths" in debunking text is inconclusive; repeating myths may unintentionally increase agreement with myths or help discredit myths. In this study we aimed to compare the effect of repeating vaccination myths and other text-based debunking strategies on parents' agreement with myths and their intention to vaccinate their children.

METHODS

For this online experiment we recruited 788 parents of children aged 0 to 5 years; 454 (58%) completed the study. We compared 3 text-based debunking strategies (repeating myths, posing questions, or making factual statements) and a control. We measured changes in agreement with myths and intention to vaccinate immediately after the intervention and at least 1 week later. The primary analysis compared the change in agreement with vaccination myths from baseline, between groups, at each time point after the intervention.

RESULTS

There was no evidence that repeating myths increased agreement with myths compared with the other debunking strategies or the control. Posing questions significantly decreased agreement with myths immediately after the intervention compared with the control (difference: -0.30 points, 99.17% confidence interval: -0.58 to -0.02, P = .004, d = 0.39). There was no evidence of a difference between other debunking strategies or the control at either time point, or on intention to vaccinate.

CONCLUSIONS

Debunking strategies that repeat vaccination myths do not appear to be inferior to strategies that do not repeat myths.

Associations between conspiracism and the rejection of scientific innovations

Public opinion regarding scientific developments such as genetically modified food can be mixed. We suggest such science-based technological innovations are rejected by some because they are perceived to be advanced as part of a conspiracy. In nationally representative samples (Australia n = 1011; New Zealand n = 754), we report the associations between five conspiracism facets and anti-science attitudes. Results indicate broad public opposition to genetically modified food and use of nuclear power, but more acceptance of renewable power, potable recycled water, 5G networks, and childhood vaccinations. There were small to moderate associations between the rejection of scientific innovations and conspiracism. Multivariate models estimating unique associations of conspiracism facets with anti-science attitudes suggested several novel and important relationships, particularly for childhood vaccination, genetically modified food, and 5G networks. We discuss the importance of examining factors such as conspiracism in understanding what may motivate and sustain rejection of scientific evidence-based claims about socially contentious technological innovations.

Social media, body satisfaction and well-being among adolescents: A mediation model of appearance-ideal internalization and comparison

Despite adolescents' prolific use of social media, relationships between social media and body satisfaction and well-being are not yet well understood, especially among boys. This study tested a sociocultural model of body image within the context of social media among adolescent boys and girls. Specifically, this study examined whether appearance-ideal internalization and social appearance comparisons mediated relationships between social media engagement (intensity and appearance-focused use) and body satisfaction and subjective well-being. Australian adolescents between 11 and 17 years (N = 1,579, M_age = 13.45 years, SD = 1.15; 55.4 % boys) completed an online survey. Structural equational modelling indicated that only higher appearance-focused social media use was directly associated with lower body satisfaction and well-being. Generally, higher appearance-ideal internalization and comparisons mediated the relationships between higher social media engagement and lower body satisfaction and well-being. Multi-group analyses indicated these relationships were equivalent across gender. Findings supported the proposed model among boys and girls and extend existing theoretical knowledge to encompass male body image and well-being. Interventions which target internalization and comparisons in the context of social media are likely to be valuable in improving body satisfaction and subjective well-being in co-educational settings.

Increased sleep predicts annual decreases in psychological distress: Results from a 6-year longitudinal panel sample

OBJECTIVE

To investigate the annual temporal ordering of sleep quantity and psychological distress, separating between-person stability from within-person change.

DESIGN

Random-intercepts cross-lagged panel model using 6 annual waves of longitudinal data from the New Zealand Attitudes Values Study postal questionnaire.

PARTICIPANTS

New Zealand Attitudes Values Study respondents in 2013, 2014, 2015, 2016, 2017, and 2018 (Ns = 17,890; 15,757; 13,904; 21,849; 17,031; and 47,462).

MEASUREMENTS

Participants were asked, "During the past month, on average, how many hours of actual sleep did you get per night?" and responded to the K6 psychological distress scale each year. They also reported their demographic characteristics.

RESULTS

Identified longitudinal associations between sleep duration and psychological distress in a traditional cross-lagged panel model were mostly attributable to the stability of the between-person differences in sleep duration and psychological distress. We provide evidence to suggest that increased sleep duration as indicated over a short period of time (ie, 1 month) predicted lower within-person levels of psychological distress the following year. Psychological distress did not predict sleep duration, in contrast.

CONCLUSIONS

Our analyses suggest that sleep duration in this sample of New Zealanders precedes psychological distress. This is significant given the propensity for short sleep in this sample and issues of poor mental health and short sleep among low SES indigenous members of this community. The promotion of adequate sleep duration may yield positive gains in psychological well-being.

The antidepressant hoax: Conspiracy theories decrease health-seeking intentions

Health-related conspiracy theories can undermine the trustworthiness of actors and institutions and may impact an individual's intention to seek help. Across three experimental studies, we investigated the consequences of exposure to an antidepressant conspiracy theory on general intentions to seek medical and psychological help. Study 1 participants (N = 299) were randomly allocated to read one of three articles (pro-conspiracy, anti-conspiracy, control) after which they completed measures of conspiracy endorsement, trust, powerlessness, and health-seeking intentions. Results suggested that exposure to antidepressant conspiracy theories significantly reduced individual's intention to seek help indirectly through decreased trust in health authorities, but not health-industry-related powerlessness. In two additional pre-registered studies, we found some support for these findings. While Study 2 (N = 244) found no support for a direct or indirect relationship between conspiracy exposure and health-seeking intentions, an exploratory analysis highlighted the importance of gender differences when investigating conspiracy exposure on intentions. Study 3 (N = 247) replicated Study 1 findings, highlighting that antidepressant conspiracy theories decrease health-seeking intentions indirectly through decreased trust and increased powerlessness. Mere exposure to antidepressant conspiracy theories had significant indirect consequences on general health-seeking intentions.

Dismantling prevention: Comparison of outcomes following media literacy and appearance comparison modules in a randomised controlled trial

A dismantling study of body dissatisfaction prevention was conducted. Adolescent girls ( N = 260) were randomly allocated to a media literacy (Happy Being Me – Media Literacy) or appearance comparison (Happy Being Me – Appearance Comparison) intervention or healthy eating behaviour control (Happy Being Me – Healthy Eating Behaviour) condition. In the Happy Being Me – Appearance Comparison condition, improvements from baseline to post-programme and follow-up for upward appearance comparison and fear of negative appearance evaluation were observed. In the Happy Being Me – Media Literacy condition, improvements were observed from baseline to post-programme for upward appearance comparison and realism scepticism. Findings were similar in a high-risk subsample and overall are moderately supportive of appearance comparison-based interventions, but less supportive of a stand-alone media literacy intervention.

Attitudes to genetically modified food over time: How trust in organizations and the media cycle predict support

This research examined public opinion toward genetically modified plants and animals for food, and how trust in organizations and media coverage explained attitudes toward these organisms. Nationally representative samples (N=8821) over 10 years showed Australians were less positive toward genetically modified animals compared to genetically modified plants for food, especially in years where media coverage was high. Structural equation modeling found that positive attitudes toward different genetically modified organisms for food were significantly associated with higher trust in scientists and regulators (e.g. governments), and with lower trust in watchdogs (e.g. environmental movement). Public trust in scientists and watchdogs was a stronger predictor of attitudes toward the use of genetically modified plants for food than animals, but only when media coverage was low. Results are discussed regarding the moral acceptability of genetically modified organisms for food, the media's role in shaping public opinion, and the role public trust in organizations has on attitudes toward genetically modified organisms.

Coupled biological oscillators in a cave insect

Insects that live in the interior of caves show the basic internal temporal organization of coupled oscillators. An analysis is made of the coupled moulting and oviposition cycles of Folsomia candida, a cave-dwelling Collembolan, with regard to their oscillatory nature, their phase dependent responses to external perturbations, the effect of coupling on these responses, and conjecture about the link of these cycles with circadian clocks in other organisms.

Prevalence and determinants of periodontal disease in Portuguese adults: results from a multifactorial approach

The purpose of the present investigation was to study prevalence of periodontal disease among 30 to 39-years-old from Oporto in the north of Portugal. In addition, an attempt was made to elucidate possible periodontal disease determinants in this population. A random sample consisting of a total of 322 individuals was drawn based on electoral lists. The attendance rate was 61%. The CPITN index was used and the results indicate a high prevalence of periodontal disease and a substantial need for periodontal treatment in this population, with 41% of the individuals investigated having one or more sites with a CPITN score 4 (pockets deeper than 5.5 mm). Dental visiting habits, gender (lower CPITN scores for females) and oral hygiene were the determinants most significantly associated with variation in CPITN scores.

Prevalence of apical periodontitis and results of endodontic treatment in an adult, Portuguese population

The present epidemiological study is derived from a random sample of 322 residents of the Porto area, aged 30-39 years. Prevalence of apical periodontitis and results of endodontic treatment were evaluated from orthopantomograms, available from 179 of a total of 197 individuals attending for examination. The results indicated a prevalence of apical periodontitis in 27% of this population. The quality of a majority (54%) of the 69 root fillings observed were found to be inadequate, (i.e. short and/or poorly condensed), but only 15 (22%) of the endodontically treated teeth presented with apical periodontitis.

Dental caries determinants in an adult Portuguese population and a comparison with Norwegian adults

The present epidemiologic dental caries study indicates a high number of decayed surfaces (mean, 13.5 +/- 11.8 (SD)) in a Portuguese population of 30- to 39-year-olds from Porto. The most influential determinants for variation in carious surfaces were oral hygiene, gender, salivary buffer capacity, and missing teeth. By entering the most influential independent variables in a final multiple classification analysis, the total explained variance in carious surfaces was 27%. A comparison with results from a similar Norwegian dental health study showed that the biologic factors of importance for number of carious surfaces were the same, whereas the sociocultural determinants differed.

Control of environmental variables in a field study using a chronobiological protocol

Field work in chronobiology usually is based on observations which differ from those in laboratory studies which are experimental. Non-invasive protocols are recommended in the field in order not to introduce additional variables. We propose an alternative strategy here. The effect of environmental cycles on biological rhythms can be estimated when the observations are made in more than one area. The areas under study must have at least one characteristic in common which is a guarantee that the limits of oscillation of an environmental cycle will be similar. This proposal has been tested using the biological system consisting of an Onagraceae plant, Ludwigia elegans, and its bee visitors, which is found in two localities at the same latitude, but at different altitudes. Under the same photoperiod, but with the mean temperature ranging within known limits, it was possible to determine temporal characteristics of the system in the field by examining the effects of the light/dark and temperature daily cycles.

Masking and the evolution of circadian rhythmicity

In spite of the clear-cut temporal features exhibited by most species, temporal characteristics have merited little attention from evolutionists. However, it is logical to assume that since the environment oscillates cyclically, organisms that adapt to it must also oscillate; that is, cyclic factors have a clear evolutionary role. This article discusses evidence that the timing system is genetically determined; the role of environmental cues such as zeitgebers and masking factors; the temporal basis of mating; and masking as a disorganizing factor.

Caries prevalence of young adults in Oslo, Norway, and Porto, Portugal. A comparative analysis

The purpose of the present study was primarily to establish the oral health status of young adults in the area of Porto, Portugal. The assessment is based on a random sample of 30- to 39-year-olds with criteria identical to those of a Norwegian study of 35-year-olds. This makes it possible also to present a comparative analysis of the caries prevalence in Oslo, Norway, and Porto, Portugal. The results indicate lower DMF scores among the Portuguese (DMFS = 46.2) than the Norwegian (DMFS = 85.0) adults. The difference is primarily due to a greater number of filled surfaces among the Norwegians (FS = 59.7) than the Portuguese (FS = 4.4). However, carious surfaces are more prevalent among Portuguese than Norwegian adults (DS = 9.2 versus DS = 3.3). Both among Portuguese and Norwegian adults, oral hygiene and dental visits seem to play an important role with regard to the prevalence of decayed surfaces. Decayed surfaces were more prevalent among men than women, and a correlation between social status and prevalence of decayed surfaces was present in both societies.

Chronobiologic aspects of a coadaptive process: the interaction of Ludwigia elegans flowers and their more frequent bee visitors

Field observations spanning 1 year of the visits of two bee species--Tetraglossula bigamica (Hymenoptera: Colletidae) and Pseudagapostemon brasiliensis (Hymenoptera: Halictidae)--to the flowers of Ludwigia elegans (Onagraceae) evinced the existence of circadian and circannual components in the rhythms of activity both of plant and bees. In addition to morphological adaptations to the flower, the bees were temporally adjusted to each other and to the flower's opening and closing mechanisms. At the observation locality (Ribeirão Preto, São Paulo, Brazil--latitude 21 degrees-21 degrees 30S), the plant bloomed year-round. The flowers of the same population open simultaneously at the onset of the photophase, pollen and nectar being available almost immediately. Withering occurs in the afternoon of the same day. Although many bee species visited the flowers, T. bigamica and P. brasiliensis were the most frequent visitors, but their yearly rhythms were phased opposite to one another. Circadian rhythms were detected in pollen and nectar harvest. Comparisons of acrophases showed significant differences for males' and females' nectar collecting rhythm and for females' pollen harvest rhythm. As for the circannual component, acrophases of all rhythms occur at progressively later times from December to July when the migration is reversed until November. These data strongly suggest that the relationship between L. elegans and T. bigamica and P. brasiliensis is in accordance with a clearly temporal pattern and that the two bee species are temporally separated in nature.

Experimental models for the study of chronoimmunomodulation (rhythms of the springtail Folsomia candida, Collembola: Isotomidae)

A third-generation cephalosporine, cefodizime, was tested in two experiments on the springtail, Folsomia candida, used as a model of infradian rhythmicity. Any effect on ecdysis (molt), oviposition and oviproduction was sought for 6, 20 or 60 ng of cefodizime administered with brewer's yeast every other day, as compared to controls given only the yeast. Results indicate that a 20-ng dose of cefodizime on alternate days may shorten an infradian period (of molt) in the springtail.

Sexual behavior elicited in cage-mates of olfactory tubercle stimulated rats

Fourteen male albino rats kept in pairs were implanted with bipolar electrodes in the olfactory tubercle. Electrical stimulation elicited a behavioral change in the cage-mates of the stimulated rats. This change consisted of increased exploratory activity in six animals. In three of these six rats, sexual behavior with mounting and pelvic thrusting was observed. The changes are described and discussed with special attention to sexual behavior.