The decay products of 222rn in etched track radon detection

Precipitation of decay products of atmospheric ²²²Rn in small containers and the effects of their precipitation on alpha-particle-track-measurements of radon activities were studied. From decay curves of decay product activities on surfaces exposed to radon-containing air the ratios ²¹⁴Pb/²¹⁸Po (=r) in the precipitates were determined. From r average ages of precipitating decay products were calculated. Average ages and r were low, indicating rapid precipitation of decay products, and decreased with container size. Activities on exposed surfaces were approximately those expected if decay products precipitate completely and uniformly on the internal surfaces of containers.Decay products precipitated on foils of correct thickness covering cellulose nitrate (CN) track detectors produce tracks. Therefore track densities produced by given radon activities are increased by such covers to extents predictable from the decay product activities on the overlays. Tracks formed under overlays may etch to larger, more vertical-sided, more easily counted forms. When suspended, uncovered, in air at distances from surfaces greater than the ranges of the alpha particles, three types of CN recorded tracks at the rate (ρ′) of 0.12 tracks cm^?2 (pCi Rn)^?1 1^?1 hr^?1 as predicted by a theoretical expression. In small containers (ρ′) varied with position and container size.     

An equation of state at subnuclear densities

An equation of state for cold matter above white dwarf densities is evaluated. The gas is considered to be a mixture of degenerate neutrons, protons and electrons combined with nuclei of one type (that is only oneA andZ value). We derive the equilibrium equations for the mixture and calculate the number densities as well as theA andZ of the nucleus. Finally we calculate an equation of state, which smoothly goes over to that of a neutron, proton electron gas mixture at a density of 5×10¹³ g/cm³.     

Equinox tidal heating of the upper atmosphere

Evaluations are presented of the time-average heating at different latitudes and heights due to energy flux divergence of the equinox diurnal and semidiurnal tides calculated by Forbes (1982a,h)from 0 to 400 km.It is found that diurnal tidal heating maximizes in the region of 80 km and semidiurnal has a sharp maximum at 108 km. Thermospheric diurnal oscillations give rise to a second region of heating that maximizes at 200 km and effectively transports energy from low to high latitudes.Global means are evaluated for the time-averaged vertical energy fluxes and heating rates: below 130 km, the results for the diurnal tide agree with those for the (1,1) mode alone, and for the semidiurnal tide, heating rates below 130 km are the same as those that would he obtained without the thermospheric semidiurnal excitation.Comparisons are made from 90 to 170 km between the combined diurnal and semidiurnal heating rates and previously reported rates due to e.u.v. radiation, S_q currents and gravity waves.     

Spatial modeling of annual minimum and maximum temperatures in Iceland

Bayesian hierarchical modeling is applied to the analysis of annual minimum and maximum temperatures. In both cases the generalized extreme value distribution is selected as the marginal distribution at each site due to its flexibility and theoretical basis. This distribution has three unknown parameters, a location parameter, a scale parameter and a shape parameter. The location and scale parameters are assumed to vary across sites while the shape parameter is assumed to be the same for all sites. The location and the scale parameters are modeled as two independent Gaussian spatial processes which are governed by the Matérn correlation function. These spatial processes play a central role in spatial predictions at unobserved sites. The location parameter is also modeled with a common time effect which includes a linear trend and a linear site effect with altitude, distance to open sea, latitude and longitude as covariates. This model allows for spatial predictions for any set of unobserved sites, the scale of the grid can be as fine as possible as long as the covariates are observed at each of the unobserved sites. Data on the annual minimum and maximum temperatures in Iceland from 1961 to 2009?at 72 sites are analyzed and used to predict the 2nd percentile of the minimum temperature for the 12-month period from July 2011 to June 2012 and the 98th percentile of maximum temperature for the year 2011 for a large set of unobserved sites across Iceland at which the covariates are available. The spatial predictions reveal that the 2nd percentile of minimum temperature for 2011 to 2012 reaches ?35°C in the central part of Iceland and ranges from ?12 to ?22°C around the coast of Iceland with the lowest coastal temperatures in the Northern part and the Northeastern part. The 98th percentile of maximum temperature in 2011 ranges from 10 to 30°C where the warmest areas are found in the Eastern part, the North-Eastern part and the Southern part of the country. The estimated increase in minimum and maximum temperatures over the years 1961 to 2009 is 0.71 and 0.47°C per decade, respectively, while the average annual temperature increased 0.24°C per decade over the same period.     

Solving the mysteries of the diffuse interstellar medium with high-resolution UV spectroscopy

Understanding the complex structure, dynamics, and ionization of gas in the nearby interstellar medium is required before one can realistically model interstellar gas in other galaxies. High-resolution ultraviolet spectra provide the essential data for such studies because the resonance lines of most important atoms, ions, and molecules are located in the ultraviolet, and high spectral resolution is needed to resolve line profiles and determine the velocity structure along a line of sight. I list ten important physical questions concerning interstellar gas that require a more sensitive spectrometer than STIS and the desired spectral resolution to answer these questions.     

Subarctic catchment water storage and carbon cycling – Leading the way for future studies using integrated datasets at Pallas,Finland

Subarctic ecohydrological processes are changing rapidly, but detailed and integrated ecohydrological investigations are not as widespread as necessary. We introduce an integrated research catchment site (Pallas) for atmosphere, ecosystems, and ecohydrology studies in subarctic conditions in Finland that can be used for a new set of comparative catchment investigations. The Pallas site provides unique observational data and high-intensity field measurement datasets over long periods. The infrastructure for atmosphere- to landscape-scale research in ecosystem processes in a subarctic landscape has recently been complemented with detailed ecohydrological measurements. We identify three dominant processes in subarctic ecohydrology: (a) strong seasonality drives ecohydrological regimes, (b) limited dynamic storage causes rapid stream response to water inputs (snowmelt and intensive storms), and (c) hydrological state of the system regulates catchment-scale dissolved carbon dynamics and greenhouse (GHG) fluxes. Surface water and groundwater interactions play an important role in regulating catchment-scale carbon balances and ecosystem respiration within subarctic peatlands, particularly their spatial variability in the landscape. Based on our observations from Pallas, we highlight key research gaps in subarctic ecohydrology and propose several ways forward. We also demonstrate that the Pallas catchment meets the need for sustaining and pushing the boundaries of critical long-term integrated ecohydrological research in high-latitude environments.     

Crossing Boundaries in a Collaborative Modeling Workspace

There is substantial literature on the importance of bridging across disciplinary and science–management boundaries. One of the ways commonly suggested to cross boundaries is for participants from both sides of the boundary to jointly produce information (i.e., knowledge co-production). But simply providing tools or bringing people together in the same room is not sufficient. Here we present a case study documenting the mechanisms by which managers and scientists collaborated to incorporate climate change projections into Colorado’s State Wildlife Action Plan. A critical component of the project was the use of a collaborative modeling and visualization workspace: the U.S. Geological Survey’s Resource for Advanced Modeling (RAM). Using video analysis and pre/post surveys from this case study, we examine how the RAM facilitated cognitive and social processes that co-produced a more salient and credible end product. This case provides practical suggestions to scientists and practitioners who want to implement actionable science.     

Microwave brightness of Saturn's rings

It is shown that a lower limit exists on the microwave brightness of the rings of Saturn, if they are assumed to be composed of Mie scatterers of geological composition. The lower limit (about 15°K) is due to scattering of planetary microwave emission. Significant variation of brightness with azimuth along the rings is expected if the particles are typically of 2–3cm radius. Implications for the multiple-scattering hypothesis of the radar cross section of the rings are noted.