Atmospheric cloud physics laboratory project study

Engineering studies were performed for the Zero-G Cloud Physics Experiment liquid cooling and air pressure control systems. A total of four concepts for the liquid cooling system was evaluated, two of which were found to closely approach the systems requirements. Thermal insulation requirements, system hardware, and control sensor locations were established. The reservoir sizes and initial temperatures were defined as well as system power requirements. In the study of the pressure control system, fluid analyses by the Atmospheric Cloud Physics Laboratory were performed to determine flow characteristics of various orifice sizes, vacuum pump adequacy, and control systems performance. System parameters predicted in these analyses as a function of time include the following for various orifice sizes: (1) chamber and vacuum pump mass flow rates, (2) the number of valve openings or closures, (3) the maximum cloud chamber pressure deviation from the allowable, and (4) cloud chamber and accumulator pressure

An expert elicitation of climate, energy and economic uncertainties

Critical energy policy decisions rely on expert assessments of key future uncertainties. But existing modelling techniques that help form these expert assessments often ignore the existence of uncertainty. Consequently, techniques to measure these uncertainties are of increasing importance. We use one technique, expert elicitation, to assess six key uncertain parameters with 25 UK energy experts across academia, government and industry. We obtain qualitative descriptions of the uncertain parameters and a novel data set of probability distributions describing individual expert beliefs. We conduct a sensitivity analysis on weights for a linear opinion pool and show that aggregated median beliefs in 2030 are: for oil price $120/barrel (90$34/tCO2e (90% CI: 5, 256) and for levelised cost of low-carbon electricity 17.1 US cents/kWh (90% CI: 8.3, 31.0). The quantitative results could inform model validation, help benchmark policy makers’ beliefs or provide probabilistic inputs to models

Exobiology in Earth orbit: The results of science workshops held at NASA, Ames Research Center

The Workshops on Exobiology in Earth Orbit were held to explore concepts for orbital experiments of exobiological interest and make recommendations on which classes of experiments should be carried out. Various observational and experimental opportunities in Earth orbit are described including those associated with the Space Shuttle laboratories, spacecraft deployed from the Space Shuttle and expendable launch vehicles, the Space Station, and lunar bases. Specific science issues and technology needs are summarized. Finally, a list of recommended experiments in the areas of observational exobiology, cosmic dust collection, and in situ experiments is presented

Multiple populations within globular clusters in Early-type galaxies Exploring their effect on stellar initial mass function estimates

It is now well-established that most (if not all) ancient globular clusters host multiple popula- tions, that are characterised by distinct chemical features such as helium abundance variations along with N-C and Na-O anti-correlations, at fixed [Fe/H]. These very distinct chemical fea- tures are similar to what is found in the centres of the massive early-type galaxies and may influence measurements of the global properties of the galaxies. Additionally, recent results have suggested that M/L variations found in the centres of massive early-type galaxies might be due to a bottom-heavy stellar initial mass function. We present an analysis of the effects of globular cluster-like multiple populations on the integrated properties of early-type galaxies. In particular, we focus on spectral features in the integrated optical spectrum and the global mass-to-light ratio that have been used to infer variations in the stellar initial mass function. To achieve this we develop appropriate stellar population synthesis models and take into account, for the first time, an initial-final mass relation which takes into consideration a varying He abundance. We conclude that while the multiple populations may be present in massive early-type galaxies, they are likely not responsible for the observed variations in the mass- to-light ratio and IMF sensitive line strengths. Finally, we estimate the fraction of stars with multiple populations chemistry that come from disrupted globular clusters within massive ellipticals and find that they may explain some of the observed chemical patterns in the centres of these galaxies

Short-Term Memory in Orthogonal Neural Networks

We study the ability of linear recurrent networks obeying discrete time dynamics to store long temporal sequences that are retrievable from the instantaneous state of the network. We calculate this temporal memory capacity for both distributed shift register and random orthogonal connectivity matrices. We show that the memory capacity of these networks scales with system size.Comment: 4 pages, 4 figures, to be published in Phys. Rev. Let

Marine sponges as microbial fermenters

The discovery of phylogenetically complex, yet highly sponge-specific microbial communities in marine sponges, including novel lineages and even candidate phyla, came as a surprise. At the same time, unique research opportunities opened up, because the microorganisms of sponges are in many ways more accessible than those of seawater. Accordingly, we consider sponges as microbial fermenters that provide exciting new avenues in marine microbiology and biotechnology. This review covers recent findings regarding diversity, biogeography and population dynamics of sponge-associated microbiota, and the data are discussed within the larger context of the microbiology of the ocean

Investment Uncertainty Under Stringent UK Decarbonisation Targets

The legally binding UK greenhouse gas emissions targets were in part derived using deterministic variants of UK MARKAL. UCL, under UKERC, has developed a new two- stage stochastic variant, which provides additional near-term insights for policy makers under future uncertainties. Significant uncertainties remain as to the level of effort required by the UK to avoid dangerous warming. In this paper, the use of cumulative CO2 targets, equivalent to 80% and 90% reductions by 2050 allow comparison between current UK policy and the modelled results. Deterministic scenarios result in steep near-term decarbonisation in part due to a social discount rate, proportional to the cumulative target. Under uncertain future cumulative CO2 emission targets, the cost of the hedging strategy is related asymmetrically to the weighting of future scenarios. When the cumulative CO2 targets are equally weighted, the near-term investment strategy lies close to that of the deterministic 90% CO2 target. This indicates that steep near-term decarbonisation is important given exponentially rising cumulative welfare costs with increasingly stringent cumulative emission targets

Risk prediction tools for cancer in primary care.

This is the final version of the article. Available from the publisher via the DOI in this record.Numerous risk tools are now available, which predict either current or future risk of a cancer diagnosis. In theory, these tools have the potential to improve patient outcomes through enhancing the consistency and quality of clinical decision-making, facilitating equitable and cost-effective distribution of finite resources such as screening tests or preventive interventions, and encouraging behaviour change. These potential uses have been recognised by the National Cancer Institute as an 'area of extraordinary opportunity' and an increasing number of risk prediction models continue to be developed. The data on predictive utility (discrimination and calibration) of these models suggest that some have potential for clinical application; however, the focus on implementation and impact is much more recent and there remains considerable uncertainty about their clinical utility and how to implement them in order to maximise benefits and minimise harms such as over-medicalisation, anxiety and false reassurance. If the potential benefits of risk prediction models are to be realised in clinical practice, further validation of the underlying risk models and research to assess the acceptability, clinical impact and economic implications of incorporating them in practice are needed

Developing Career Development Profiles of Student-Athletes: A Comparison with Non-Athletes

Student-athletes' and non-athletes' scores on several career-related assessments were compared. During the 1990-91 academic year at a medium-sized, state-supported university in the South, a sample of 41 student-athletes (83% males and 17% females) and 178 non-athletes (29% males and 71% females) completed the Values Scale (Super & Nevill, 1985b), Career Development Inventory (Super, Thompson, Lindeman, Jordaan, & Myers, 1981), and Salience Inventory (Super & Nevill, 1985a). Completion of these instruments was required for a semester-long, three-credit course in career/life planning. The student-athletes were non-revenue scholarship athletes representing a NCAA Division II institution in soccer, basketball, and tennis. Both groups contained students representing all class ranks, with a majority in both groups being white (93% of the student-athlete group and 69% of the non-athlete group. Results of two-way ANOVAs indicated that student-athletes highly value physical activity and spend more time in leisure activities than non-athletes. Only one significant gender effect was found: females had a higher score on the combined knowledge scale (M = 100.29) than males (M = 85.16) (F(1, 138) = 8.43, p < .006). The combined knowledge scale score is a linear combination of scores in decision-making and world-of-work information. This result indicates that females may be better able to apply career development principles to decision-making scenarios as well as demonstrate more knowledge of what it takes to get a job and succeed. No differences in career maturity scores were found. Implications for programming to accommodate the special needs of student-athletes are discussed

Critical mid-term uncertainties in long-term decarbonisation pathways

Over the next decade, large energy investments are required in the UK to meet growing energy service demands and legally binding emission targets under a pioneering policy agenda. These are necessary despite deep mid-term (2025–2030) uncertainties over which national policy makers have little control. We investigate the effect of two critical mid-term uncertainties on optimal near-term investment decisions using a two-stage stochastic energy system model. The results show that where future fossil fuel prices are uncertain: (i) the near term hedging strategy to 2030 differs from any one deterministic fuel price scenario and is structurally dissimilar to a simple ‘average’ of the deterministic scenarios, and (ii) multiple recourse strategies from 2030 are perturbed by path dependencies caused by hedging investments. Evaluating the uncertainty under a decarbonisation agenda shows that fossil fuel price uncertainty is very expensive at around £20 billion. The addition of novel mitigation options reduces the value of fossil fuel price uncertainty to £11 billion. Uncertain biomass import availability shows a much lower value of uncertainty at £300 million. This paper reveals the complex relationship between the flexibility of the energy system and mitigating the costs of uncertainty due to the path-dependencies caused by the long-life times of both infrastructures and generation technologies