The Stability of the orbits of Earth-mass planets in and near the habitable zones of known exoplanetary systems

We have shown that Earth-mass planets could survive in variously restricted regions of the habitable zones (HZs) of most of a sample of nine of the 93 main-sequence exoplanetary systems confirmed by May 2003. In a preliminary extrapolation of our results to the other systems, we estimate that roughly a third of the 93 systems might be able to have Earth-mass planets in stable, confined orbits somewhere in their HZs. Clearly, these systems should be high on the target list for exploration for terrestrial planets. We have reached this conclusion by launching putative Earth-mass planets in various orbits and following their fate with a mixed-variable symplectic integrator

Prospects for Extrasolar "Earths" in Habitable Zones

We have shown that Earth-mass planets could survive in variously restricted regions of the habitable zones (HZs) of most of a sample of nine of the 102 main-sequence exoplanetary systems confirmed by 19 November 2003. In a preliminary extrapolation of our results to the other systems, we estimate that roughly a half of these systems could have had an Earth-mass planet confined to the HZ for at least the most recent 1000 Ma. The HZ migrates outwards during the main-sequence lifetime, and so this proportion varies with stellar age. About two thirds of the systems could have such a planet confined to the HZ for at least 1000 Ma at sometime during the main-sequence lifetime. Clearly, these systems should be high on the target list for exploration for terrestrial planets. We have reached this conclusion by launching putative Earth-mass planets in various orbits and following their fate with mixed-variable symplectic and hybrid integrators. Whether the Earth-mass planets could form in the HZs of the exoplanetary systems is an urgent question that needs further study.Comment: 7 pages, 2 figure

Cladding strategies for building-integrated photovoltaics

Photovoltaic cladding on the surfaces of commercial buildings has the potential for considerable reductions in carbon emissions due to embedded renewable power generation displacing conventional power utilization. In this paper, a model is described for the optimization of photovoltaic cladding densities on commercial building surfaces. The model uses a modified form of the ‘fill factor’ method for photovoltaic power supply coupled to new regression-based procedures for power demand estimation. An optimization is included based on a defined ‘mean index of satisfaction’ for matched power supply and demand (i.e., zero power exportation to the grid). The mean index of satisfaction directly translates to the reduction in carbon emission that might be expected over conventional power use. On clear days throughout the year, reductions of conventional power use of at least 60% can be achieved with an optimum cladding pattern targeted to lighting and small power load demands

Experimental and analytical strains in an edge-cracked sheet

Elastoplastic strain distribution in edge-cracked metal sheets determined by optical interference and moire technique

Habitability of known exoplanetary systems based on measured stellar properties

At present, because of observational selection effects, we know of no exoplanetary systems with any planetary masses close to that of the Earth. We have therefore used computer models to see whether such planets could be dynamically stable in the presence of the more massive planets known to be present, and in particular whether planets with roughly an Earth mass could remain confined to the classical habitable zone (HZ) for long enough for life to have emerged. Measured stellar properties have been used to determine for each system the present location of the HZ. We have also determined the critical distances from the orbit of each giant planet within which an Earth-mass planet would suffer large orbital changes. We then evaluated the present habitability of each and every exoplanetary system by examining the penetration of these critical distances into the HZ. The critical distances can be obtained by extensive computer modelling of an exoplanetary system. This is far too time consuming to apply to all of the 150 or so systems already known, and to keep up with the latest discoveries. Therefore, in earlier work we studied a few systems in great detail, and developed a speedier means of obtaining the critical distances. We summarize this comparatively quick method here. We can then evaluate comparatively quickly the present habitability of each exoplanetary system by examining the penetration of the critical distance(s) into the HZ. The results are encouraging for astrobiology.Comment: Accepted for publication by The Astrophysical Journal. A few revisions have been made following suggestions by the refere

Experiences of people taking opioid medication for chronic non-malignant pain : a qualitative evidence synthesis using meta-ethnography

Objective To review qualitative studies on the experience of taking opioid medication for chronic non-malignant pain (CNMP) or coming off them. Design This is a qualitative evidence synthesis using a seven-step approach from the methods of meta-ethnography. Data sources and eligibility criteria We searched selected databases—Medline, Embase, AMED, Cumulative Index to Nursing and Allied Health Literature, PsycINFO, Web of Science and Scopus (Science Citation Index and Social Science Citation Index)—for qualitative studies which provide patients’ views of taking opioid medication for CNMP or of coming off them (June 2017, updated September 2018). Data extraction and synthesis Papers were quality appraised using the Critical Appraisal Skills Programme tool, and the GRADE-CERQual (Grading of Recommendations Assessment, Development and Evaluation working group - Confidence in Evidence from Reviews of Qualitative research) guidelines were applied. We identified concepts and iteratively abstracted these concepts into a line of argument. Results We screened 2994 unique citations and checked 153 full texts, and 31 met our review criteria. We identified five themes: (1) reluctant users with little choice; (2) understanding opioids: the good and the bad; (3) a therapeutic alliance: not always on the same page; (4) stigma: feeling scared and secretive but needing support; and (5) the challenge of tapering or withdrawal. A new overarching theme of ‘constantly balancing’ emerged from the data. Conclusions People taking opioids were constantly balancing tensions, not always wanting to take opioids, and weighing the pros and cons of opioids but feeling they had no choice because of the pain. They frequently felt stigmatised, were not always ‘on the same page’ as their healthcare professional and felt changes in opioid use were often challenging

Rex E. Lee Conference on the Office of the Solicitor General of the United States: Clinton II Panel

I will say a few words about Dickerson, both because Michael has made it impossible not to and also because in some ways it represents the very best about how all of the wonderful, tried-and-true processes of the SG\u27s Office ought to work. Dickerson was very much like the other case that Michael talked about (which is one of, I think, two significant privilege controversies which the Independent Counsel laid on our doorstep). These cases may have appeared to the outside world as paradigmatically cases in which we would be hearing from the White House, or talking to the White House, or thinking about things other than the long-term institutional interests of the United States. But absolutely nothing of the sort ever happened, nor was any effort made by any political person to intrude in our decision-making policy

A practical model for the assessment of thermal comfort in train carriages

A practical model has been developed for the assessment of human thermal comfort in rail carriages. The PMV model is based upon the existing ISO 7730 standard for assessing moderate thermal environments (PMV: Fanger 1970), with correction factors to account for the extreme environmental stimuli that may be experienced by some passengers seated next to windows (i.e. exposure to direct solar radiation or the effects of a cold window). Three sets of laboratory experiments and four field trials were conducted. Environmental conditions and mean skin temperature were recorded and thermal rating questionnaires filled in by participants. [Continues.

The impact of broadband in schools

The report reviews evidence for the impact of broadband in English schools, exploring; Variations in provision in level of broadband connectivity; Links between the level of broadband activity and nationally accessible performance data; Aspects of broadband connectivity and the school environment that contribute to better outcomes for pupils and teachers; Academic and motivational benefits associated with educational uses of this technology