5,097 research outputs found

    The temporal changes in the emission spectrum of Comet 9P/Tempel 1 after Deep Impact

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    The time dependence of the changes in the emission spectra of Comet 9P/Tempel 1 after Deep Impact are derived and discussed. This was a unique event because for the first time it gave astronomers the opportunity to follow the time history of the formation and decay of O(1S), OH, CN, C2, C3, NH, and NH2. Least squares fits of a modified Haser model with constraints using known rate constants were fit to the observed data. In the case of OH a simple two-step Haser model provides a reasonable fit to the observations. Fitting the emissions from O(1S), CN, C2, C3, NH, and NH2 requires the addition of a delayed component to a regular two or three step Haser model. From this information a picture of the Deep Impact encounter emerges where there is an initial formation of gas and dust, which is responsible for the prompt emission that occurs right after impact. A secondary source of gas starts later after impact when the initial dust has dissipated enough so that solar radiation can reach the surface of freshly exposed material. The implications of this and other results are discussed in terms of the implications on the structure and composition of the comet's nucleus.Comment: Accepted for publication in The Astrophysical Journal; 26 pages including 8 figures and 1 tabl

    The role of parenthood in worry about overheating in homes and implications for energy use - two online survey studies from the UK and the US

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    Climate change brings an increase in temperatures and a higher frequency of heatwaves. Both have been linked to a rise in suicide rates and violent crime on a population level. However, little is known about the link between mental health and ambient temperatures on an individual level and for particular subgroups. Overheating poses health risks to children and can cause disturbed sleep; leading to the expectation that parents are more worried about their homes getting too hot than non-parents. We conducted two online survey studies (N = 1000 each) in the UK and the US to understand to what extent parents and an age-matched comparison group without children are worried about overheating and how they differ in their mitigation actions. Findings did not support the main hypotheses around greater overheating concern amongst parents in general, mothers or those with very young children. However, parents indicated a greater likelihood to upgrade / install air-conditioning (US) and to get electric fans (UK). Parents in the UK indicated using more mitigation options to cope with overheating and parents in the US, whilst not reporting doing more actions, were more likely to use air-conditioning to deal with overheating than non-parents. Finally, those parents who mentioned health impacts for children as a reason for concern about overheating, were more concerned about overheating than parents who had other reasons than children’s health as a reason for being concerned about overheating. In summary, being or becoming a parent might have implications for cooling energy use and parental concern; however, many open questions remain

    Analysis of the effects of baffles on combustion instability

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    An analytical model has been developed for predicting the effects of baffles on combustion instability. This model has been developed by coupling an acoustic analysis of the wave motion within baffled chambers with a model for the oscillatory combustion response of a propellant droplet developed by Heidmann. A computer program was developed for numerical solution of the resultant coupled equations. Diagnostic calculations were made to determine the reasons for the improper prediction. These calculations showed that the chosen method of representing the combustion response was a very poor approximation. At the end of the program, attempts were made to minimize this effect but the model still improperly predicts the stability trends. Therefore, it is recommended that additional analysis be done with an improved approximation

    Emotions and thermal comfort – feeling warmer when feeling happier

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    Providing thermal comfort (TC) in buildings typically uses around 30% of developed nations’ energy and carbon emissions. Thermal comfort is provided by constraining ambient temperatures to within narrowly defined ‘comfortable’ ranges traditionally based on physiological heat balance models of the human body. Our understanding of what drives thermal comfort perception is still limited however, and while physiological parameters have been identified for decades, research on psychological parameters of comfort is still rather limited. The basic emotions have not been studied in relationship to thermal comfort, so in this study, we investigated the relationship between emotional state, i.e. feeling happy or sad, and thermal comfort perception. A recent study has shown that the various basic emotions are associated with specific perceived activation state of the body (Nummenmaa, Glerean, Hari, & Hietanen, 2014) which we hypothesized would translate in different comfort states. Feeling happy would, through higher perceived bodily activation, translate to feeling warmer or more thermally comfortable - whereas feeling sad would lead to feeling colder or less thermally comfortable, because of the associated perceived lower bodily activation. We designed an experimental study using Amazon Mechanical Turk (Paolacci, Chandler, & Ipeirotis, 2010). N = 300 Turkers were recruited and randomly assigned to recall either a happy autobiographical episode or a sad one to induce a happy or sad emotional state (Briñol, Petty, & Barden, 2007). The valid sample encompassed N = 273. A manipulation check revealed that the emotional manipulation worked. There was a significant effect of emotional state on the standard ASHRAE comfort survey question “How are you feeling in this moment from 1 (cold) to 7 (hot)?”. Those feeling happy reported feeling significantly warmer than those feeling sad [t(269) = 3.66, p < .001]. However, there was no difference in the two other outcomes variables, estimate of room temperature and rating of how thermally comfortable one felt - the latter also being a standard thermal comfort survey question. We conclude that there is some evidence for a relationship between emotional state and thermal perception in feeling of warm or cold that warrants further research on this topic. The data also indicate a dissociation between various thermal comfort related outcomes measures, posing a methodological challenge that needs addressing

    SnapShot: Tumor evolution

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    Understanding how tumors grow and evolve over time is crucial to help shed light on the underlying reasons why treatments fail and tumors metastasize. This SnapShot provides a brief introduction into the main concepts of tumor evolution

    What motivates retrofitting? Results of a nationally representative sample in Great Britain

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    Energy use in buildings is one of the largest contributors to total energy consumption. The UK Government established the goal of reducing carbon emissions from homes by 29% by 2020, with energy efficiency improvements forming a central part of the plans. However, the recent ‘Green Deal’ policy to promote energy-efficiency measures in homes through financial incentives had very little uptake. In a nationally representative survey, we assessed framing effects on the hypothetical uptake of free home insulation provided by the energy supplier. The frames tested were: (1) monetary savings, (2) a warmer home, (3) carbon savings, (4) health benefits, and (5) social norms. The option emphasizing monetary savings was associated with significantly higher likeliness to take up the offer than any of the other options, which all received similar mean ratings. Higher trust in the energy supplier was associated with higher likeliness to participate in the scheme. Financial benefits seem to be the greatest incentive for retrofit measures, supporting policy based on them. In this context we critically discuss the apparent failure of the Green Deal, and suggest how the importance of trust in the energy supplier could be used in the future

    Results of ultra-low level 71ge counting for application in the Gallex-solar neutrino experiment at the Gran Sasso Underground Physics Laboratory

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    It has been experimentally verified that the Ultra-Low-Level Counting System for the Gallex solar neutrino experiment is capable of measuring the expected solar up silon-flux to plus or minus 12% during two years of operation

    The use of graft materials in vaginal pelvic floor surgery

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    ObjectiveTo review recent literature on graft materials used in vaginal pelvic floor surgery.MethodsA Pubmed‐search (“anterior vaginal wall” or “cystocele”), (“posterior vaginal wall” or “rectocele”) and (“vaginal vault” or “pelvic prolapse”) and (“mesh” or “erosion” or “graft” or “synthetic”) from 1995 to 2005 was performed; recent reviews [Birch C. The use of prosthetics in pelvic reconstructive surgery. Best Pract Res Clin Obstet Gynaecol 2005;19:979–91 [1]; Maher C, Baessler K. Surgical management of anterior vaginal wall prolapse: an evidence‐based literature review. Int Urogynecol J Pelvic Floor Dysfunct 2005 (May 25) [Electronic Publication] [2]; Maher C, Baessler K. Surgical management of posterior vaginal wall prolapse: an evidence‐based literature review. Int Urogynecol J Pelvic Floor Dysfunct 2006;17:84–8 [3]; Altman D, Mellgren A, Zetterstrom J. Rectocele repair using biomaterial augmentation: current documentation and clinical experience. Obstet Gynecol Surv 2005;60:753–60 [4]] were added.ResultThere are few prospective randomized trials that prove the benefit of implanting grafts in vaginal pelvic floor surgery. Many articles are retrospective case series with small sample sizes or incomplete outcome variables. Serious complications such as erosions are often not mentioned. Inconsistent or unclear criteria for anatomic cure make it difficult to compare outcomes. Quality of life issues such as dyspareunia, urinary or bowel symptoms are often ignored.ConclusionDue to a lack of well‐designed prospective randomized trials, recommendations for using graft materials in vaginal reconstructive surgery cannot be made. At this time, grafts should have limited use in a carefully selected patient population.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135429/1/ijgo279.pd