Spontaneous internal desynchronization of locomotor activity and body temperature rhythms from plasma melatonin rhythm in rats exposed to constant dim light

BACKGROUND: We have recently reported that spontaneous internal desynchronization between the locomotor activity rhythm and the melatonin rhythm may occur in rats (30% of tested animals) when they are maintained in constant dim red light (LL(dim)) for 60 days. Previous work has also shown that melatonin plays an important role in the modulation of the circadian rhythms of running wheel activity (R(w)) and body temperature (T(b)). The aim of the present study was to investigate the effect that desynchronization of the melatonin rhythm may have on the coupling and expression of circadian rhythms in R(w )and T(b). METHODS: Rats were maintained in a temperature controlled (23–24°C) ventilated lightproof room under LL(dim )(red dim light 1 μW/cm(2 )[5 Lux], lower wavelength cutoff at 640 nm). Animals were individually housed in cages equipped with a running wheel and a magnetic sensor system to detect wheel rotation; T(b )was monitored by telemetry. T(b )and R(w )data were recorded in 5-min bins and saved on disk. For each animal, we determined the mesor and the amplitude of the R(w )and T(b )rhythm using waveform analysis on 7-day segments of the data. After sixty days of LL(dim )exposure, blood samples (80–100 μM) were collected every 4 hours over a 24-hrs period from the tail artery, and serum melatonin levels were measured by radioimmunoassay. RESULTS: Twenty-one animals showed clear circadian rhythms R(w )and T(b), whereas one animal was arrhythmic. R(w )and T(b )rhythms were always strictly associated and we did not observe desynchronization between these two rhythms. Plasma melatonin levels showed marked variations among individuals in the peak levels and in the night-to-day ratio. In six rats, the night-to-day ratio was less than 2, whereas in the rat that showed arrhythmicity in R(w )and T(b )melatonin levels were high and rhythmic with a large night-to-day ratio. In seven animals, serum melatonin levels peaked during the subjective day (from CT0 to CT8), thus suggesting that in these animals the circadian rhythm of serum melatonin desynchronized from the circadian rhythms of R(w )and T(b). No significant correlation was observed between the amplitude (or the levels) of the melatonin profile and the amplitude and mesor of the R(w )and T(b )rhythms. CONCLUSION: Our data indicate that the free-running periods (τ) and the amplitude of R(w )and T(b )were not different between desynchronized and non-desynchronized rats, thus suggesting that the circadian rhythm of serum melatonin plays a marginal role in the regulation of the R(w )and T(b )rhythms. The present study also supports the notion that in the rat the circadian rhythms of locomotor activity and body temperature are controlled by a single circadian pacemaker

Does attractiveness influence condom use intentions in heterosexual men? An experimental study

Objectives: Judgements of attractiveness have been shown to influence the character of social interactions. The present study sought to better understand the relationship between perceived attractiveness, perceived sexual health status and condom use intentions in a heterosexual male population.Setting: The study employed an electronic questionnaire to collect all data, during face-to-face sessions.Participants: 51 heterosexual, English-speaking men aged between 18 and 69?years.Outcome measures: Men were asked to rate the attractiveness of 20 women on the basis of facial photographs, to estimate the likelihood that each woman had a sexually transmitted infection (STI) and to indicate their willingness to have sex with or without a condom with each woman.Results: The more attractive a woman was judged to be on average, the more likely participants would be willing to have sex with her (p<0.0001) and the less likely they were to intend to use a condom during sex (p<0.0001). Multivariate analysis revealed that higher condom use intentions towards a particular woman were associated with lower ratings of her attractiveness (p<0.0005), higher ratings of her STI likelihood (p<0.0001), the participant being in an exclusive relationship (p=0.002), having a less satisfactory sex life (p=0.015), lower age (p=0.001), higher number of sexual partners (p=0.001), higher age at first intercourse (p=0.002), higher rates of condomless sex in the last 12?months (p<0.043) and lower confidence in their ability to assess whether or not a woman had an STI (p=0.001). The more attractive a participant judged himself to be, the more he believed that other men like him would engage in condomless sex (p=0.001) and the less likely he was to intend to use a condom himself (p=0.02).Conclusions: Male perceptions of attractiveness influence their condom use intentions; such risk biases could profitably be discussed during sex education sessions and in condom use promotion interventions

Preparing for and Responding to Disturbance: Examples from the Forest Sector in Sweden and Canada

Coping or adaptation following large-scale disturbance may depend on the political system and its preparedness and policy development in relation to risks. Adaptive or foresight planning is necessary in order to account and plan for potential risks that may increase or take place concurrently with climate change. Forests constitute relevant examples of large-scale renewable resource systems that have been directly affected by recent environmental and social changes, and where different levels of management may influence each other. This article views disturbances in the forest sectors of Sweden and Canada, two large forest nations with comparable forestry experiences, in order to elucidate the preparedness and existing responses to multiple potential stresses. The article concludes that the two countries are exposed to stresses that indicate the importance of the governing and institutional system particularly with regard to multi-level systems including federal and EU levels. While economic change largely results in privatization of risk onto individual companies and their economic resources (in Canada coupled with a contestation of institutional systems and equity in these), storm and pest outbreaks in particular challenge institutional capacities at administrative levels, within the context provided by governance and tenure systems.In Sweden, funding from the research agency FORMAS, the MISTRA Arctic Futures programme, and the Future Forests programme (funded by research agency MISTRA, the forest industries, Umeå University and the Swedish University of Agricultural Sciences) as well as from the EU for data collection is acknowledged. Ryan Bullock acknowledges funding provided by the Social Sciences and Humanities Research Council and by the Mistra Arctic Futures programme for preparing this paper.https://www.mdpi.com/1999-4907/2/2/50

Seasonal and herbivore-induced dynamics of foliar glucosinolates in wild cabbage (Brassica oleracea)

Levels of plant secondary metabolites are not static and often change in relation to plant ontogeny. They also respond to abiotic and biotic changes in the environment, e.g., they often increase in response to biotic stress, such as herbivory. In contrast with short-lived annual plant species, especially those with growing periods of less than 2–3 months, investment in defensive compounds of vegetative tissues in biennial and perennial species may also vary over the course of an entire growing season. In garden experiments, we investigated the dynamics of secondary metabolites, i.e. glucosinolates (GSLs) in the perennial wild cabbage (Brassica oleracea), which was grown from seeds originating from three populations that differ in GSL chemistry. We compared temporal long-term dynamics of GSLs over the course of two growing seasons and short-term dynamics in response to herbivory by Pieris rapae caterpillars in a more controlled greenhouse experiment. Long-term dynamics differed for aliphatic GSLs (gradual increase from May to December) and indole GSLs (rapid increase until mid-summer after which concentrations decreased or stabilized). In spring, GSL levels in new shoots were similar to those found in the previous year. Short-term dynamics in response to herbivory primarily affected indole GSLs, which increased during the 2-week feeding period by P. rapae. Herbivore-induced changes in the concentrations of aliphatic GSLs were population-specific and their concentrations were found to increase in primarily one population only. We discuss our results considering the biology and ecology of wild cabbage

Marine Invaders in the Northeast: Rapid Assessment Survey of Non-native and Native Marine Species of Floating Dock Communities, August 2003

In his seminal book on The Ecology of Invasions by Animals and Plants, Elton (1958) laid the foundation for the science of biological invasions. He identified the importance of human-mediated vectors as means of transporting organisms to new locations and discussed invasions in the context of ecological impacts and evolutionary consequences. Elton even identified what needed to be done to prevent practical and ecological damages from invaders--keep them out, eradicate them, and if all else fails, manage them at acceptable levels. We have not been vigilant in applying this knowledge to marine ecosystems, although this is changing. Our ability to detect changes in numbers and rate of marine introductions depends on well-documented lists of species in time and space, appropriate identification of non-native species, and careful records that follow changes in nomenclature, distribution, potential vectors, and ecosystem alterations caused by non-native species.United States. Environmental Protection Agency (Grant X83055701

Cluster-Cluster Lensing and the Case of Abell 383

Extensive surveys of galaxy clusters motivate us to assess the likelihood of cluster-cluster lensing (CCL), namely, gravitational-lensing of a background cluster by a foreground cluster. We briefly describe the characteristics of CCLs in optical, X-ray and SZ measurements, and calculate their predicted numbers for $\Lambda$CDM parameters and a viable range of cluster mass functions and their uncertainties. The predicted number of CCLs in the strong-lensing regime varies from several ($<10$) to as high as a few dozen, depending mainly on whether lensing triaxiality bias is accounted for, through the c-M relation. A much larger number is predicted when taking into account also CCL in the weak-lensing regime. In addition to few previously suggested CCLs, we report a detection of a possible CCL in A383, where background candidate high-$z$ structures are magnified, as seen in deep Subaru observations.Comment: 9 pages, 5 figures, submitted to MNRA

The Equity Impact Vaccines May Have On Averting Deaths And Medical Impoverishment In Developing Countries.

With social policies increasingly directed toward enhancing equity through health programs, it is important that methods for estimating the health and economic benefits of these programs by subpopulation be developed, to assess both equity concerns and the programs' total impact. We estimated the differential health impact (measured as the number of deaths averted) and household economic impact (measured as the number of cases of medical impoverishment averted) of ten antigens and their corresponding vaccines across income quintiles for forty-one low- and middle-income countries. Our analysis indicated that benefits across these vaccines would accrue predominantly in the lowest income quintiles. Policy makers should be informed about the large health and economic distributional impact that vaccines could have, and they should view vaccination policies as potentially important channels for improving health equity. Our results provide insight into the distribution of vaccine-preventable diseases and the health benefits associated with their prevention