The Role of Organic Peroxides in the Induction of Mutations

The discovery by Wyss, Stone, and Clark' that bacteria grown on a substrate recently exposed to ultra-violet light are subject to high mutation rates shows clearly that some meta-stable chemical substance, probably of no great complexity, is an intermediate in at least a part of the mutagenic action of ultra-violet light. It was supposed that hydrogen peroxide might be responsible for these results, but subsequent work has shown that this cannot be the whole explanation. [2] However, organic peroxides are known to be formed by the action of ultra-violet light on many compounds and such peroxides might very well be the intermediate agents producing the substrate irradiation effect

The impact of life events on adult physical and mental health and well being: longitudinal analysis using the GoWell Health and Well-being Survey

Background: It is recognised that life events (LEs) which have been defined as incidents necessitating adjustment to habitual life either permanently or temporarily, not only have the potential to be detrimental to health and well-being, but research suggests some LEs may be beneficial. This study aimed to determine the individual and cumulative occurrence of LEs; and to establish their effect on health and well-being. Results: Demographic factors (gender, age and highest educational attainment), LE occurrence and self-reported health data were collected as part of the longitudinal GoWell community health and wellbeing survey (2008–2011). Self-reported health was measured using the SF-12 questionnaire for physical (SF-12 PCS) and mental health (SF-12 MCS) and the Warwick–Edinburgh mental well-being scale (WEMWBS) for well-being. Statistical analysis was performed using SPSSv21 and level of significance was set at p < 0.05. Results showed that the sample was 61.6 % (n = 768) female; 20.4 % (n = 254) were aged 16–39 years, 46.1 % (n = 575) 40–64 years and 33.5 % (n = 418) were over 65 years; 68.8 % (n = 819) had no qualifications/Scottish leaving certificates, with the remaining 31.2 % (n = 372) having their highest educational qualification above Scottish leaving certificates. Health score means were 49.3 SF-12 mental health component score (SF-12 MCS); 42.1 SF-12 physical health component score (SF-12 PCS); and 49.2 WEMWBS. Participants experienced 0–7 LEs over a three year period, with the most common being: housing improvement (44.9 %), house move (36.8 %), health event (26.3 %) and bereavement (25.0 %). Overall, an increase in LEs was associated with a health score decrease. Five LEs (relationship breakdown, health event, bereavement, victimisation and house move) had negative impacts on SF-12 MCS and two (new job/promotion and parenthood) had positive impacts. For SF-12 PCS only three (health event, bereavement and housing improvement) had a negative impact. Six (health event, victimisation, bereavement, relationship breakdown housing move and improvement) had negative impacts on well-being and two (new job/promotion, marriage) had positive effects. Conclusions: Findings from the current study confirm LEs have both detrimental and beneficial impacts on health and well-being. Further research is required to disentangle the complexity of LEs and the ways they affect health and well-being

Hypothesis Article Signatures of a Shadow Biosphere

Abstract Astrobiologists are aware that extraterrestrial life might differ from known life, and considerable thought has been given to possible signatures associated with weird forms of life on other planets. So far, however, very little attention has been paid to the possibility that our own planet might also host communities of weird life. If life arises readily in Earth-like conditions, as many astrobiologists contend, then it may well have formed many times on Earth itself, which raises the question whether one or more shadow biospheres have existed in the past or still exist today. In this paper, we discuss possible signatures of weird life and outline some simple strategies for seeking evidence of a shadow biosphere

Vegetarian diets are associated with healthy mood states: a cross-sectional study in Seventh Day Adventist adults

<p>Abstract</p> <p>Background</p> <p>The physical health status of vegetarians has been extensively reported, but there is limited research regarding the mental health status of vegetarians, particularly with regard to mood. Vegetarian diets exclude fish, the major dietary source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), critical regulators of brain cell structure and function. Omnivorous diets low in EPA and DHA are linked to impaired mood states in observational and experimental studies.</p> <p>Methods</p> <p>We examined associations between mood state and polyunsaturated fatty acid intake as a result of adherence to a vegetarian or omnivorous diet in a cross-sectional study of 138 healthy Seventh Day Adventist men and women residing in the Southwest. Participants completed a quantitative food frequency questionnaire, Depression Anxiety Stress Scale (DASS), and Profile of Mood States (POMS) questionnaires.</p> <p>Results</p> <p>Vegetarians (VEG:n = 60) reported significantly less negative emotion than omnivores (OMN:n = 78) as measured by both mean total DASS and POMS scores (8.32 ± 0.88 vs 17.51 ± 1.88, <it>p </it>= .000 and 0.10 ± 1.99 vs 15.33 ± 3.10, <it>p </it>= .007, respectively). VEG reported significantly lower mean intakes of EPA (<it>p </it>< .001), DHA (<it>p </it>< .001), as well as the omega-6 fatty acid, arachidonic acid (AA; <it>p </it>< .001), and reported higher mean intakes of shorter-chain α-linolenic acid (<it>p </it>< .001) and linoleic acid (<it>p </it>< .001) than OMN. Mean total DASS and POMS scores were positively related to mean intakes of EPA (<it>p </it>< 0.05), DHA (<it>p </it>< 0.05), and AA (<it>p </it>< 0.05), and inversely related to intakes of ALA (<it>p </it>< 0.05), and LA (<it>p </it>< 0.05), indicating that participants with low intakes of EPA, DHA, and AA and high intakes of ALA and LA had better mood.</p> <p>Conclusions</p> <p>The vegetarian diet profile does not appear to adversely affect mood despite low intake of long-chain omega-3 fatty acids.</p

The astrobiology primer: An outline of general knowledge - Version 1, 2006

Peer reviewe

Historical Science, Experimental Science, and the Scientific Method

Wielu naukowców sądzi, że istnieje jedna, interdyscyplinarna metoda uprawiania dobrej nauki. Wzorcowe przykłady czerpane są jednak z obrębu klasycznych nauk eksperymentalnych. Czasem, kiedy hipotez o charakterze historycznym nie można testować w kontrolowanych warunkach laboratoryjnych, twierdzi się, że badania historyczne mają gorszą jakość niż badania eksperymentalne. Celem niniejszego artykułu jest wykazanie, na podstawie przykładów z różnych dyscyplin historycznych, że to przekonanie jest błędne. Po pierwsze, pogląd o rzekomej wyższości badań eksperymentalnych wynika z przyjęcia takich koncepcji metodologii naukowej (indukcjonizmu baconowskiego i falsyfikacjonizmu), które mają poważne mankamenty, zarówno na płaszczyźnie logicznej, jak też jako ujęcia rzeczywistych praktyk naukowców. Po drugie, chociaż między metodologiami nauk eksperymentalnych i nauk historycznych zachodzą zasadnicze różnice, związane są one z pewną wszechobecną właściwością świata przyrody - czasową asymetrią przyczynowości. Nie da się zatem utrzymać twierdzenia, że nauki historyczne są pod względem metodologicznym gorsze od nauk eksperymentalnych.Many scientists believe that there is a uniform, interdisciplinary method for the practice of good science. The paradigmatic examples, however, are drawn from classical experimental science. Insofar as historical hypotheses cannot be tested in controlled laboratory settings, historical research is sometimes said to be inferior to experimental research. Using examples from diverse historical disciplines, this paper demonstrates that such claims are misguided. First, the reputed superiority of experimental research is based upon accounts of scientific methodology (Baconian inductivism or falsificationism) that are deeply flawed, both logically and as accounts of the actual practices of scientists. Second, although there are fundamental differences in methodology between experimental scientists and historical scientists, they are keyed to a pervasive feature of nature, a time asymmetry of causation. As a consequence, the claim that historical science is methodologically inferior to experimental science cannot be sustained