Temperature and Density on the Forsterite Liquid-Vapor Phase Boundary.

The physical processes during planet formation span a large range of pressures and temperatures. Giant impacts, such as the one that formed the Moon, achieve peak pressures of 100s of GPa. The peak shock states generate sufficient entropy such that subsequent decompression to low pressures intersects the liquid-vapor phase boundary. The entire shock-and-release thermodynamic path must be calculated accurately in order to predict the post-impact structures of planetary bodies. Forsterite (Mg2SiO4) is a commonly used mineral to represent the mantles of differentiated bodies in hydrocode models of planetary collisions. Here, we performed shock experiments on the Sandia Z Machine to obtain the density and temperature of the liquid branch of the liquid-vapor phase boundary of forsterite. This work is combined with previous work constraining pressure, density, temperature, and entropy of the forsterite principal Hugoniot. We find that the vapor curves in previous forsterite equation of state models used in giant impacts vary substantially from our experimental results, and we compare our results to a recently updated equation of state. We have also found that due to under-predicted entropy production on the principal Hugoniot and elevated temperatures of the liquid vapor phase boundary of these past models, past impact studies may have underestimated vapor production. Furthermore, our results provide experimental support to the idea that giant impacts can transform much of the mantles of rocky planets into supercritical fluids.

Niche similarities among introduced and native mountain ungulates.

The niche concept provides a strong foundation for theoretical and applied research among a broad range of disciplines. When two ecologically similar species are sympatric, theory predicts they will occupy distinct ecological niches to reduce competition. Capitalizing on the increasing availability of spatial data, we built from single species habitat suitability models to a multispecies evaluation of the niche partitioning hypothesis with sympatric mountain ungulates: native bighorn sheep (BHS; Ovis canadensis) and introduced mountain goats (MTG; Oreamnos americanus) in the northeast Greater Yellowstone Area. We characterized seasonal niches using two-stage resource selection functions with a used-available design and descriptive summaries of the niche attributes associated with used GPS locations. We evaluated seasonal similarity in niche space according to confidence interval overlap of model coefficients and similarity in geographic space by comparing model predicted values with Schoener's D metric. Our sample contained 37,962 summer locations from 53 individuals (BHS = 31, MTG = 22), and 79,984 winter locations from 57 individuals (BHS = 35, MTG = 22). Slope was the most influential niche component for both species and seasons, and showed the strongest evidence of niche partitioning. Bighorn sheep occurred on steeper slopes than mountain goats in summer and mountain goats occurred on steeper slopes in winter. The pattern of differential selection among species was less prevalent for the remaining covariates, indicating similarity in niche space. Model predictions in geographic space showed broad seasonal similarity (summer D = 0.88, winter D = 0.87), as did niche characterizations from used GPS locations. The striking similarities in seasonal niches suggest that introduced mountain goats will continue to increase their spatial overlap with native bighorn. Our results suggest that reducing densities of mountain goats in hunted areas where they are sympatric with bighorn sheep and impeding their expansion may reduce the possibility of competition and disease transfer. Additional studies that specifically investigate partitioning at finer scales and along dietary or temporal niche axes will help to inform an adaptive management approach.

Quality Assurance in Archaeological Survey.

To have confidence in the results of an archaeological survey, whether for heritage management or research objectives, we must have some assurance that the survey was carried out to a reasonably high standard. This paper discusses the use of Quality Assurance (QA) approaches and empirical methods for estimating surveys' effectiveness at discovering archaeological artifacts as a means for ensuring quality standards. We illustrate with the example of two surveys in Cyprus and Jordan in which resurvey, measurement of surveyor "sweep widths," and realistic estimates of survey coverage allow us to evaluate explicitly the probability that the survey missed pottery or lithics, as well as to decide when survey has been thorough enough to warrant moving to another survey unit.

Estimating the risk of long-term erectile, urinary and bowel symptoms resulting from prostate cancer treatment.

Reports on long-term complications resulting from treatment for localized prostate cancer are very inconsistent. In order to estimate the risks of long-term erectile dysfunction, urine symptoms and bowel symptoms following prostatectomy (RP), external conventional or conformal beam radiation (ERT or CRT) and brachytherapy (BRT), 98 papers from the PubMed and Cochrane Clinical Trial databases were selected, reviewed and critically evaluated. The majority of papers were institution-based retrospective and prospective follow-up studies; only two of these studies measured the risk of developing more than one treatment complication. Due to differences in study designs and populations, it is difficult to directly compare studies and not meaningful to calculate summary estimates. In addition to focusing on randomized clinical trials and well-designed population based studies, future research should adopt standardized methodologies and should measure the risk of developing more than one treatment complication.

Age, medical conditions, and gender as interactive predictors of cognitive performance: the effects of selective survival.

The interaction of age, medical conditions, and gender on free-recall and mental status test performance was analyzed in two large survey samples of older adults. Age, gender, and the presence of medical conditions interacted with recall and mental status in Study 1 (n = 2,695) and mental status in Study 2 (n = 6,299). For men, those with one or more medical conditions declined more steeply with age than those with no conditions. For women, this relationship was reversed. The findings suggest survival effects, whereby those who lived to old age with medical conditions and were selected into the sample had high levels of cognitive functioning. The age at which these effects are seen vary with gender because women survive longer than men.

Individual differences in 16-year memory changes.

The authors analyzed the role of individual differences in age, gender, and 16-year declines in reasoning and vocabulary as predictors of 16-year changes in text and list recall and recognition in 82 adults aged 55-81 years at baseline. Declines in reasoning as well as being older at baseline predicted declines in text recall. Male gender and declining in vocabulary predicted declines in list recall. There were no reliable predictors of declines in recognition. The findings suggest that changes in abilities, as well as age and gender, predict declines on memory tasks. However, the specific predictors varied across tasks.

Humoral immune response to Rocky Mountain spotted fever in experimentally infected guinea pigs: immunoprecipitation of lactoperoxidase 125I-labeled proteins and detection of soluble antigens of Rickettsia rickettsii.

Rickettsia rickettsii, the etiologic agent of Rocky Mountain spotted fever, purified from infected L-929 cells by density gradient banding were extrinsically radioiodinated with lactoperoxidase. Immunodominant 125I-labeled antigens were identified by radioimmunoprecipitation of detergent-solubilized antigens with protein A-Sepharose and anti-R. rickettsii sera collected 0, 3, 7, 11, 32, and 163 days after infection of guinea pigs. The average fever greater than or equal to 40 degrees C was detected by days 3 and 4 after infection with 6 X 10(7) and 6 X 10(6) PFU, respectively. By microagglutination and complement fixation assays, anti-R. rickettsii antibodies were detected as early as day 3 after infection, with titers increasing markedly between days 7 and 163. Convalescent sera, collected on day 163, from infected guinea pigs were used to identify seven 125I-labeled antigens with apparent molecular sizes of 186,000 (I), 145,000 (II), 49,000 (III), 32,000 (IV), 27,500 (V), 17,500 (VI), and 16,500 (VII) daltons. Differences in antibody reactivity and specificity against the seven antigens were demonstrated with serially obtained sera. Sera from a guinea pig infected with 6 X 10(7) PFU exhibited antibody-antigen interactions with all seven 125I-labeled antigens by day 7, whereas the same antibody activity required 32 days for an animal infected with 6 X 10(6) PFU. Prominent antibody activities toward proteins II and IV were demonstrated both early and late after infection. The fluids obtained from infected L-929 cells contained three soluble antigens which were detected with the 11-, 32-, and 163-day sera by an immunodiffusion assay. The soluble and 125I-labeled antigens of R. rickettsii identified in this study may be important candidates for vaccines against Rocky Mountain spotted fever.