Neuropsychological Functioning of Homeless Men

Numerous biological and psychological factors associated with impaired neurological functioning have been identified as common among the homeless, but there has been relatively little systematic examination of the cognitive functioning of homeless people. This study explored the neuropsychological functioning of 90 homeless men. There was great variability in their test scores, but the presence of possible cognitive impairment was detected in 80% of the sample. Average general intellectual functioning and reading abilities were found to be relatively low, and the incidence of impairments in reading, new verbal learning, memory, and attention and concentration was high. These findings suggest that the homeless men in this study had considerable assessment and treatment needs that were not being met by most of the health and social services offered to them

Radiative Impacts of Volcanic Aerosol in the Arctic

High latitude volcanic eruptions are high-frequency and intensity events capable of releasing large amounts of aerosols into the environment. Studies have shown that the Arctic is particularly sensitive to radiative perturbations due to aerosols, and a high sensitivity to volcanic aerosols would be expected. Despite the potential for volcanic aerosols to significantly perturb the Arctic radiation balance, the radiative impacts of volcanic aerosols in the Arctic are poorly understood and have received less attention than the effects of other aerosol types that are often present in the region, both natural and anthropogenic. A novel review of this topic is presented in detail in this chapter, focusing on the current state of the knowledge and the natural complexities involved with the problem, the important research tools, and the improvements that can be made over the status quo. The Arctic environment is both unique and complicated, and the perturbations caused by volcanic aerosol need to be examined in a regional context. An introduction to remote sensing and data collection in the Arctic is provided because there are often specific challenges, including high surface reflectivities, persistent meteorological clouds, the lack of winter daylight, and harsh conditions that hamper both in situ and remote data collection. Methods for tracking both aerosol and gas plumes in the Arctic that can help mitigate these issues are introduced. In addition to the physical constraints of data collection presented by the Arctic environment, volcanic aerosol is a complex mixture of varying aerosol compositions and sizes. Dealing with the nature of volcanic aerosol for optical calculations is further described, leading into a detailed discussion of the radiative impacts of volcanic plumes in the atmosphere. Radiative forcing comparisons of other aerosol types with comparable plume characteristics (e.g., thicknesses and optical depths) suggest that aerosol layers composed of significant proportions of volcanic ash can dominate the aerosol forcing in the region. Similar comparisons for ash deposits with other types of deposits that can be present in the region emphasize the ability of volcanic ash to produce large, and in some cases extreme, loadings that reduce albedo, which can have profound impacts on the Arctic radiation balance and hydrological cycle. The strengths and shortcomings of volcanic ash transport and dispersion models are reviewed and recommendations are made for future research that would strengthen the use of these models in Arctic environments. In particular, ash aggregation (or the sticking together of ash particles) is often not considered fully in transport modeling, and the consequences of this are discussed. Finally, we present a review of secondary volcanic impacts to oceans and ecosystems that have not been constrained in an Arctic context but are potentially important to the Arctic environment and the global CO2 cycle

The Mid-IR Spectral Effects of Darkening Agents and Porosity on the Silicate Surface Features of Airless Bodies

We systematically measured the mid-IR spectra of different mixtures of three silicates (antigorite, lizardite, and pure silica) with varying effective porosities and amounts of darkening agent (iron oxide and carbon). These spectra have broad implications for interpretation of current and future mission data for airless bodies, as well as for testing the capabilities of new instruments. Serpentines, such as antigorite and lizardite, are common to airless surfaces, and their mid-IR spectra in the presence of darkening agents and different surface porosities would be typical for those measured by spacecraft. Silica has only been measured in the plumes of Enceladus and presents exciting possibilities for other Saturn-system surfaces due to long range transport of E-ring material. Results show that the addition of the IR-transparent salt, KBr, to simulate surface porosity affected silicate spectra in ways that were not predictable from linear mixing models. The strengthening of silicate bands with increasing pore space, even when only trace amounts of KBr were added, indicates that spectral features of porous surfaces are more detectable in the mid-IR. Combining iron oxide with the pure silicates seemed to flatten most of the silicate features, but strengthened the reststrahlen band of the silica. Incorporating carbon with the silicates weakened all silicate features, but the silica bands were more resistant to being diminished, indicating silica may be more detectable in the mid-IR than the serpentines. We show how incorporating darkening agents and porosity provides a more complete explanation of the mid-IR spectral features previously reported on worlds such as Iapetus

Introduction of the \u3csup\u3e305\u3c/sup\u3eArg→\u3csup\u3e305\u3c/sup\u3eSer mutation in the large extrinsic loop E of the CP43 protein of Synechocystis sp. PCC 6803 leads to the loss of cytochrome c\u3csub\u3e550\u3c/sub\u3e binding to Photosystem II

CP43, a component of Photosystem II (PSII) in higher plants, algae and cyanobacteria, is encoded by the psbC gene. Previous work demonstrated that alteration of an arginine residue occurring at position 305 to serine produced a strain (R305S) with altered PSII characteristics including lower oxygen-evolving activity, fewer assembled reaction centers, higher sensitivity to photoinactivation, etc. [Biochemistry 38 (1999) 1582]. Additionally, it was determined that the mutant exhibited an enhanced stability of its S2 state. Recently, we observed a significant chloride effect under chloride-limiting conditions. The mutant essentially lost the ability to grow photoautotrophically, assembled fewer fully functional PSII reaction centers and exhibited a very low rate of oxygen evolution. Thus, the observed phenotype of this mutation is very similar to that observed for the psbV mutant, which lacks cytochrome c550 (Biochemistry 37 (1998) 1551). A His-tagged version of the R305S mutant was produced to facilitate the isolation of PSII particles. These particles were analyzed for the presence of cytochrome c550. Reduced minus oxidized difference spectroscopy and chemiluminescence examination of Western blots indicated that cytochrome c550 was absent in these PSII particles. Whole cell extracts from the R305S mutant, however, contained a similar amount of cytochrome c550 to that observed in the control strain. These results indicate that the mutation R305S in CP43 prevents the strong association of cytochrome c550 with the PSII core complex. We hypothesize that this residue is involved in the formation of the binding domain for the cytochrome. © 2002 Elsevier Science B.V. All rights reserved

GeoLab's First Field Trials, 2010 Desert RATS: Evaluating Tools for Early Sample Characterization

As part of an accelerated prototyping project to support science operations tests for future exploration missions, we designed and built a geological laboratory, GeoLab, that was integrated into NASA's first generation Habitat Demonstration Unit-1/Pressurized Excursion Module (HDU1-PEM). GeoLab includes a pressurized glovebox for transferring and handling samples collected on geological traverses, and a suite of instruments for collecting preliminary data to help characterize those samples. The GeoLab and the HDU1-PEM were tested for the first time as part of the 2010 Desert Research and Technology Studies (DRATS), NASA's analog field exercise for testing mission technologies. The HDU1- PEM and GeoLab participated in two weeks of joint operations in northern Arizona with two crewed rovers and the DRATS science team

Raising awareness of research evidence among health professionals delivering dementia care: Are knowledge translation workshops useful?

Providing information about the latest research via educational sessions to health professionals caring for people with dementia may be insufficient to drive change. This project explored self-reported impacts on practice change of adding information about knowledge translation (KT) to a national dementia education program. Six national workshop days were held. Each provided the option of participating in a Principles of KT and innovation implementation seminar in addition to a clinical topic update (sexualities and dementia, or managing behavioral and psychological symptoms of dementia). Six months postworkshop, 321 participants were invited to complete a research utilization survey. Seventy-five responded. KT seminar participants were more likely to report instrumental outcomes (e.g. changed policies, procedures) than those who did not participate in the KT seminar. Including KT information in educational sessions for health professionals may increase the likelihood of practice change in the field of dementia care and warrants further research