145 research outputs found
Specific roles of 5′ RNA secondary structures in stabilizing transcripts in chloroplasts
RNA secondary structures, e.g. stem–loops that are often found at the 5′ and 3′ ends of mRNAs, are in many cases known to be crucial for transcript stability but their role in prolonging the lifetime of transcripts remains elusive. In this study we show for an essential RNA-stabilizing stem–loop at the 5′ end of rbcL gene transcripts in Chlamydomonas that it neither prevents ribonucleases from binding to the RNA nor impedes their movement along the RNA strand. The stem–loop has a formative function in that it mediates folding of a short sequence around its base into a specific RNA conformation, consisting of a helical and single-stranded region, i.e. the real structure required for longevity of rbcL transcripts in chloroplasts. Disturbing this structure renders transcripts completely unstable, even if the sequence of this element is not altered. The requirement of a specific 5′ sequence and structure for RNA longevity suggests an interaction of this element with a trans-acting factor that protects transcripts from rapid degradation in chloroplasts
Comparing nuclear power trajectories in Germany and the UK: from ‘regimes' to ‘democracies’ in sociotechnical transitions and Discontinuities
This paper focuses on arguably the single most striking contrast in contemporary major energy politics in Europe (and even the developed world as a whole): the starkly differing civil nuclear policies of Germany and the UK. Germany is seeking entirely to phase out nuclear power by 2022. Yet the UK advocates a ‘nuclear renaissance’, promoting the most ambitious new nuclear construction programme in Western Europe.Here,this paper poses a simple yet quite fundamental question: what are the particular divergent conditions most strongly implicated in the contrasting developments in these two countries. With nuclear playing such an iconic role in historical discussions over technological continuity and transformation, answering this may assist in wider understandings of sociotechnical incumbency and discontinuity in the burgeoning field of‘sustainability transitions’. To this end, an ‘abductive’ approach is taken: deploying nine potentially relevant criteria for understanding the different directions pursued in Germany and the UK. Together constituted by 30 parameters spanning literatures related to socio-technical regimes in general as well as nuclear technology in particular, the criteria are divided into those that are ‘internal’ and ‘external’ to the ‘focal regime configuration’ of nuclear power and associated ‘challenger technologies’ like renewables.
It is ‘internal’ criteria that are emphasised in conventional sociotechnical regime theory, with ‘external’ criteria relatively less well explored. Asking under each criterion whether attempted discontinuation of nuclear power would be more likely in Germany or the UK, a clear picture emerges. ‘Internal’ criteria suggest attempted nuclear discontinuation should be more likely in the UK than in Germany– the reverse of what is occurring.
‘External’ criteria are more aligned with observed dynamics –especially those relating to military nuclear commitments and broader ‘qualities of democracy’. Despite many differences of framing concerning exactly what constitutes ‘democracy’, a rich political science literature on this point is unanimous in characterising Germany more positively than the UK. Although based only on a single case,a potentially important question is nonetheless raised as to whether sociotechnical regime theory might usefully give greater attention to the general importance of various aspects of democracy in constituting conditions for significant technological discontinuities and transformations. If so, the policy implications are significant. A number of important areas are identified for future research, including the roles of diverse understandings and specific aspects of democracy and the particular relevance of military nuclear commitments– whose under-discussion in civil nuclear policy literatures raises its own questions of democratic accountability
The effect of knowledge of results upon contingent negative variation in a reaction time situation with a variable foreperiod
Trends in the perceived body size of adolescent males and females in Scotland, 1990–2014: changing associations with mental well-being
Objectives: This paper explores trends in Scottish adolescents’ body size perceptions and associated mental well-being outcomes. Methods: Data were collected on Scottish 11, 13 and 15-year olds by the Health Behaviour in School-aged Children study between 1990 and 2014 (n=42,312). Logistic regression was used to examine changes in the prevalence of over- and underweight perceptions. Ordinal and linear regression was used to examine changes in the association between body perception and mental well-being. Results: Little change was observed in over- or under-weight perceptions between 1990 and 2014. However, relative to those perceiving their body as ‘about right’, those perceiving themselves as overweight reported decreasing confidence (all groups), decreasing happiness (11- and 13-year old girls) and increasing psychological symptoms (all girls and 15 year-old boys). Perceived underweight is associated with poor well-being, especially in males, but we present little evidence that this is a recent phenomenon. Conclusions: We present evidence suggesting that the influence of body image on adolescent mental health is increasing over time. This may play a role in the recently observed worsening of mental well-being in Scottish adolescents.Publisher PDFPeer reviewe
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Judging the difference between attractiveness and health: does exposure to model images influence the judgments made by men and women?
Recent research has shown facial adiposity (apparent weight in the face) to be a significant predictor of both attractiveness and health, thus making it an important determinant of mate selection. Studies looking at the relationship between attractiveness and health have shown that individuals differentiate between the two by preferring a lower weight for attractiveness than for health in female faces. However, these studies have either been correlational studies, or have investigated weight perceived from only the face. These differences have been discussed with regard to sociocultural factors such as pressure from parents, peers and also media, which has been seen to have the highest influence. While exposure to media images has been shown to influence women’s own body image, no study has yet directly tested the influence of these factors on people’s preferred weight in other women’s bodies. Here we examine how a short exposure to images of models influences men’s and women’s judgments of the most healthy looking and attractive BMI in Malaysian Chinese women’s bodies by comparing differences in preferences (for attractiveness and health) between groups exposed to images of models of varying attractiveness and body weight. Results indicated that participants preferred a lower weight for attractiveness than for health. Further, women’s but not men’s preferred BMI for attractiveness, but not health, was influenced by the type of media images to which they were exposed, suggesting that short term exposure to model images affect women’s perceptions of attractiveness but not health
A Systemic approach to scoping of factors influencing more sustainable land use in Herefordshire
Defining and putting into practice sustainable land use is a complex, systemic problem. Systems models and techniques were used in a study of Herefordshire to clarify the situation and identify the potential for a more locally focused, learning-based approach to land use. Issues included: (i) uncertainty about the boundary of a 'system of sustainable Herefordshire land use'; (ii) the complexity of economic flows in the county and the absence of some critical data; (iii) the importance of the Herefordshire landscape to tourism and the role of agriculture as a determinant of the state of that landscape; (iv) weakness of the institutional linkage between tourism and agriculture; (v) the current lack of inclusion of many relevant stakeholders in concerted action. Factors favouring a learning approach included a strong local identity, local food-related developments, and educational initiatives. Barriers to such an approach included questions of power and landholding, government policies, and attitudes and skills within organizations. These findings are considered in relation to the wider debate over approaches to sustainability
Residential Radon and Brain Tumour Incidence in a Danish Cohort
BACKGROUND: Increased brain tumour incidence over recent decades may reflect improved diagnostic methods and clinical practice, but remain unexplained. Although estimated doses are low a relationship between radon and brain tumours may exist. OBJECTIVE: To investigate the long-term effect of exposure to residential radon on the risk of primary brain tumour in a prospective Danish cohort. METHODS: During 1993-1997 we recruited 57,053 persons. We followed each cohort member for cancer occurrence from enrolment until 31 December 2009, identifying 121 primary brain tumour cases. We traced residential addresses from 1 January 1971 until 31 December 2009 and calculated radon concentrations at each address using information from central databases regarding geology and house construction. Cox proportional hazards models were used to estimate incidence rate-ratios (IRR) and 95% confidence intervals (CI) for the risk of primary brain tumours associated with residential radon exposure with adjustment for age, sex, occupation, fruit and vegetable consumption and traffic-related air pollution. Effect modification by air pollution was assessed. RESULTS: Median estimated radon was 40.5 Bq/m(3). The adjusted IRR for primary brain tumour associated with each 100 Bq/m(3) increment in average residential radon levels was 1.96 (95% CI: 1.07; 3.58) and this was exposure-dependently higher over the four radon exposure quartiles. This association was not modified by air pollution. CONCLUSIONS: We found significant associations and exposure-response patterns between long-term residential radon exposure radon in a general population and risk of primary brain tumours, adding new knowledge to this field. This finding could be chance and needs to be challenged in future studies
Challenges and Lessons Learned from fabrication, testing and analysis of eight MQXFA Low Beta Quadrupole magnets for HL-LHC
By the end of October 2022, the US HL-LHC Accelerator Upgrade Project (AUP)
had completed fabrication of ten MQXFA magnets and tested eight of them. The
MQXFA magnets are the low beta quadrupole magnets to be used in the Q1 and Q3
Inner Triplet elements of the High Luminosity LHC. This AUP effort is shared by
BNL, Fermilab, and LBNL, with strand verification tests at NHMFL. An important
step of the AUP QA plan is the testing of MQXFA magnets in a vertical cryostat
at BNL. The acceptance criteria that could be tested at BNL were all met by the
first four production magnets (MQXFA03-MQXFA06). Subsequently, two magnets
(MQXFA07 and MQXFA08) did not meet some criteria and were disassembled. Lessons
learned during the disassembly of MQXFA07 caused a revision to the assembly
specifications that were used for MQXFA10 and subsequent magnets. In this
paper, we present a summary of: 1) the fabrication and test data of all the
MQXFA magnets; 2) the analysis of MQXFA07/A08 test results with
characterization of the limiting mechanism; 3) the outcome of the
investigation, including the lessons learned during MQXFA07 disassembly; and 4)
the finite element analysis correlating observations with test performance
Anatomical study of the female reproductive system and bacteriome of Diaphorina citri Kuwayama, (Insecta: Hemiptera, Liviidae) using micro-computed tomography
Huanglongbing (HLB) (citrus greening disease) is one of the most serious bacterial diseases of citrus. It
is caused by (1) Candidatus Liberibacter africanus, transmitted by Trioza erytreae and (2) C.L. asiaticus
and C.L. americanus, transmitted by Diaphorina citri. As part of a multidisciplinary project on D. citri
(www.citrusgreening.org), we made a detailed study, using micro-computed tomography, of the female
abdominal terminalia, reproductive system (ovaries, accessory glands, spermatheca, colleterial (=
cement) gland, connecting ducts, and ovipositor) and bacteriome, which we present here. New terms
and structures are introduced and described, particularly concerning the spermatheca, ovipositor and
bacteriome. The quality of images and bacteriome reconstructions are comparable, or clearer, than
those previously published using a synchrotron or fuorescence in situ hybridisation (FISH). This study:
reviews knowledge of the female reproductive system and bacteriome organ in D. citri; represents
the frst detailed morphological study of D. citri to use micro-CT; and extensively revises existing
morphological information relevant to psylloids, hemipterans and insects in general. High quality
images and supplementary videos represent a signifcant advance in knowledge of psylloid anatomy
and are useful tools for future research and as educational aids.Kansas State University (KSU)
S15192.01University of Granada, USDA-NIFA
S15192.01
2014-70016-2302
Fluctuations in active membranes
Active contributions to fluctuations are a direct consequence of metabolic
energy consumption in living cells. Such metabolic processes continuously
create active forces, which deform the membrane to control motility,
proliferation as well as homeostasis. Membrane fluctuations contain therefore
valuable information on the nature of active forces, but classical analysis of
membrane fluctuations has been primarily centered on purely thermal driving.
This chapter provides an overview of relevant experimental and theoretical
approaches to measure, analyze and model active membrane fluctuations. In the
focus of the discussion remains the intrinsic problem that the sole fluctuation
analysis may not be sufficient to separate active from thermal contributions,
since the presence of activity may modify membrane mechanical properties
themselves. By combining independent measurements of spontaneous fluctuations
and mechanical response, it is possible to directly quantify time and
energy-scales of the active contributions, allowing for a refinement of current
theoretical descriptions of active membranes.Comment: 38 pages, 9 figures, book chapte
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