Europa: Prospects for an ocean and exobiological implications

As far as we know, Earth is the only planet in our solar system that supports life. It is natural, therefore, that our understanding of life as a planetary phenomenon is based upon Earth-like planets. There are environments in the solar system where liquid water, commonly believed to be a prerequisite for biological activity, may exist in a distinctly non-Earth-like environment. One such location is Europa, one of the Galilean satellites of Jupiter. The possibility that liquid water exists on Europa presents us with some interesting exobiological implications concerning the potential of the satellite to support life. Topics include the following: an ocean on Europa; thermal evolution of Europa; Europa's three models; exobiological implications; early conditions of Europa; low-temperature abiotic chemistry; possibility of the emergence of life on Europa; prerequisites for the habitability of Europa; energy sources for biosynthesis and metabolic activity; habitability of Europa by anaerobic life; and habitability by aerobic life

Individual differences in visual and olfactory cue preference and use by cats (Felis catus)

Highlights • Eight cats were trained in a T-maze using a two-alternative forced choice procedure. • Cats could use either an olfactory or visual cue to locate a food reward. • Cues were then put in conflict to determine which was preferred for the task. • Most cats used the visual cue to learn the location of the food. • Preferences were stable, repeatable and rapidly learned. -------------------------------------------------------------------------------- Abstract Animals are constantly presented with stimuli through different sensory challenges, which may sometimes contain contradictory information and so they must decide which is more salient in a given situation. Both vision and olfaction are extensively utilised by the domestic cat (Felis catus) in a variety of biological contexts, but which modality tends to take priority when the two channels contain information of similar potential value is unknown, as is the tendency for different individuals to use different cues in relation to the same situation. Such individual difference may have important clinical implications as it may help to explain why animals living within the same house may respond differently to the same environment. For example a change in the olfactory features of the environment may be stressful to an individual who has a bias towards using this sensory modality, but have no significant impact on individuals who rely more on visual cues for orientation. Eight cats were trained in a T-maze using a two-alternative forced choice procedure. The positive and negative stimuli presented both visual and olfactory information. Thus, there were two cues that the cats could use in order to make the discrimination. After reaching criterion for their training stimuli the six successful cats were presented with a feature mismatch test in which the positive visual stimuli were combined with the negative olfactory stimuli and vice versa. This investigated which cues were of greater salience to them. Four out of six cats showed a significant preference (P = 0.022- 0.006) for the visual cue, but one individual showed a consistent preference for using the olfactory cue (P = 0.019). To investigate whether the cats using visual cues had learned anything about the olfactory stimulus, four were given an additional test in which they were presented with the olfactory stimulus alone. Three out of four cats successfully made this discrimination, (P = 0.006-0.003, unsuccessful cat P = 0.076). This demonstrated that the cats had the potential to use olfactory cues in the absence of visual ones. These results highlight the importance of considering sensory preferences as an individual trait, which may vary substantially from population level effects

Potential Environmental Impacts of Hydrogen-based Transportation and Power Systems

Hydrogen (H2) offers advantages as an energy carrier: minimal discharge of pollutants, production from multiple sources, increased thermodynamic efficiencies compared to fossil fuels, and reduced dependence on foreign oil. However, potential impacts from the H2 generation processes, transport and distribution of H2, and releases of H2 into the atmosphere have been proposed. The goal of this project was to analyze the effects of emissions of hydrogen, the six criteria pollutants and greenhouse gases on climate, human health, materials and structures. This project was part of a larger effort by DOE to assess the life-cycle costs and benefits and environmental impacts to inform decisions regarding future hydrogen research. Technical Approach: A modeling approach was developed and used to evaluate the potential environmental effects associated with the conversion of the on-road vehicle fleet from fossil-fuel vehicles to hydrogen fuel cell vehicles. GATOR-GCMOM was the primary tool used to predict atmospheric concentrations of gases and aerosols for selected scenarios. This model accounts for all feedbacks among major atmospheric processes based on first principles. The future scenarios and the emission rates selected for this analysis of hydrogen environmental effects are based on the scenarios developed by IPCC. The scenarios selected for the model simulations are a 2000 and 2050 A1B base cases, and a 2050 A1B case with hydrogen fuel cell vehicles (HFCVs). The hydrogen fuel cell scenario assumed conversion of 90% of fossil-fuel on-road vehicles (FFOV) in developed countries and 45% of FFOVs vehicles in other countries to HFCVs, with the H2 produced by steam-reforming of natural gas (SHFCVs). Simulations were conducted to examine the effect of converting the worldâÂÂs FFOVs to HFCVs, where the H2 is produced by wind-powered electrolysis (WHFCVs). In all scenarios a 3% leakage of H2 consumed was assumed. Two new models were developed that provide the ability to evaluate a wider range of conditions and address some of the uncertainties that exist in the evaluation of hydrogen emissions. A simplified global hydrogen cycle model that simulates hydrogen dynamics in the troposphere and stratosphere was developed. A Monte Carlo framework was developed to address hydrogen uptake variability for different types of ecosystems. Findings 1.Converting vehicles worldwide in 2050 to SHFCVs at 90% penetration in developed countries and 45% penetration in other countries is expected to reduce NOx, CO, CO2, CH4, some other organic gases, ozone, PAN, black carbon, and other particle components in the troposphere, but may increase some other organic gases, depending on emissions. Conversion to SHFCVs is also expected to cool the troposphere and warm the stratosphere, but to a lesser extent than WHFCVs. Finally, SHFCVs are expected to increase UTLS ozone while decreasing upper stratospheric ozone, but to a lesser extent than WHFCVs. 2.The predicted criteria pollutant concentrations from the GATOR-GCMOM simulations indicated that near-surface annual mean concentrations in the US are likely to increase from the 2000 base case to the 2050 A1B base case for CO2 and ozone due to the increased economic activity, but to decrease for CO, NO2, SO2, and PM10 due to improved pollution control equipment and energy efficiencies. The shift to SHFCVs in 2050 was predicted to result in decreased concentrations for all the criteria pollutants, except for SO2 and PM10. The higher predicted concentrations for SO2 and PM10 were attributed to increased emissions using the steam-reforming method to generate H2. If renewable methods such as wind-based electrolysis were used to generate H2, the emissions of SO2 and PM10 would be lower. 3.The effects on air quality, human health, ecosystem, and building structures were quantified by comparing the GATOR-GCMOM model output and accepted health and ecosystem effects levels and ambient air quality criteria. Shifting to HFCVs is expected to result in improved air quality and benefits to human health. Shifting to HFCVs is unlikely to result in damage to buildings. 4.Results are thought to be robust for larger leakage rates of H2 and for greater penetrations of HFCVs, since the controlling factor for stratospheric ozone impacts is the reduction in fossil-fuel greenhouse gases and the resulting surface cooling, which reduces water vapor emissions and stratospheric warming, which increases tropopause stability reducing water vapor transport to the stratosphere. 5.The supplemental modeling results were generally supportive of the results from the GATOR-GCMOM simulations, and recommendations for additional analyses were made. Extending the duration of the simulation to coincide with the time required for hydrogen mixing ratios to attain a steady state condition was recommended. Further evaluation of algorithms to describe hydrogen uptake in the model was also recommended

Comparative analysis of pesticide effects on natural enemies in western orchards: A synthesis of laboratory bioassay data

Pesticides are commonly used for pest management in apple, pear and walnut orchards in the western U.S. and may disrupt biological control of secondary pests in these crops. A comparative analysis was made of results obtained from a series of laboratory bioassays of acute mortality and life table response experiments to estimate lethal and sublethal effects of eight pesticides on seven natural enemy species through use of stage-structured population models. Even though a number of the pesticides tested were reduced-risk products, all of them with the exception of copper plus mancozeb and chlorantraniliprole, caused more than 80% acute mortality of at least one life stage of at least one of the natural enemy species at a full field-rate concentration and could thus be considered moderately harmful according to the International Organization for Biological Control classification for laboratory bioassays. Important sublethal effects included reductions in daily fecundity and egg fertility. From integration of the lethal and sublethal effects in matrix models, the mean of the estimated intrinsic rates of increase for natural enemy species was negative for exposure to cyantraniliprole, lambda-cyhalothrin and spinetoram, but positive and not significantly different from the control for exposure to chlorantraniliprole, copper plus mancozeb, novaluron, and sulfur. For comparisons among pesticides, there appears to be considerable variation in response among natural enemy species that can only be represented effectively from a full life table response experiment and a population-level endpoint, whereas among natural enemy species, their population-level response to the range of pesticides tested could frequently be represented by acute adult mortality alone

Give us a game : evaluating the opportunities that exist for English footballers to play in the English Premier League

The purpose of this study was to provide a detailed, large-scale retrospective analysis of the number of English footballers that have been developed to play in the English Premier League (EPL) over twenty seasons. Unlike previous research, we examined appearance data as opposed to percentage of squad data enabling a more accurate representation of English players appearing in the EPL. The findings revealed a steady decline in the number and proportion of appearances made by English players in the EPL throughout the twenty season period. However, the results also indicated that the rate of decline had abated since the inception of UEFA's home-grown rule. The results support the view that opportunities for indigenous players have diminished since the EPL's inception. Given the short-term, results-focused culture that prevails in the EPL, this would appear to present a major challenge for governing bodies, particularly those working in elite player development. Discussion surrounding how these challenges might be met is presented