Ionization vacuum gage starts quickly, is unaffected by spurious currents

Ionization vacuum gage with a switch-operated starting device and a microammeter begins functioning quickly in a high vacuum. The microammeter is also protected by its circuit design from spurious currents

Ionization vacuum gauge Patent

Ionization vacuum gag

Automatic Chemical Processing Systems for Extraterrestrial Biochemical Investigations

Implementing the concept of planetary exploration is a formidable task. Laboratory procedures and techniques that are performed routinely by scientists and technicians must be performed remotely, automatically, and reliably for long periods of time without direct human intervention. The subtle and sophisticated reasoning, planning, and execution that lies behind well-conducted research in terrestrial laboratories must be incorporated into the careful original design and mechanization of extraterrestrial experiments. Mechanisms capable of automation for use in batch chemical processing of surface samples for scientific payloads have been devised and tested. Elemental processing operations common to a wide variety of possible life detection and biochemical characterization experiments were identified. It was determined that one device could perform a multiplicity of analyses if it could perform a limited number of elemental processing operations. Mechanisms were then designed for performing such elemental processing operations, and a breadboard processing device was fabricated incorporating the various processing operations, some completely automated (such as reagent metering) and others manually operated. The tremendous flexibility of the device to perform a wide variety of chemical procedures is evident. Tests of the breadboard in performing aqueous and organic extractions of soil samples indicate that completely automated, flight worthy chemical processing systems possessing great experimental flexibility are feasible and reliable

Neighborhood and community interactions determine the spatial pattern of tropical tree seedling survival

Factors affecting survival and recruitment of 3531 individually mapped seedlings of Myristicaceae were examined over three years in a highly diverse neotropical rain forest, at spatial scales of 1–9 m and 25 ha. We found convincing evidence of a community compensatory trend (CCT) in seedling survival (i.e., more abundant species had higher seedling mortality at the 25-ha scale), which suggests that density-dependent mortality may contribute to the spatial dynamics of seedling recruitment. Unlike previous studies, we demonstrate that the CCT was not caused by differences in microhabitat preferences or life history strategy among the study species. In local neighborhood analyses, the spatial autocorrelation of seedling survival was important at small spatial scales (1–5 m) but decayed rapidly with increasing distance. Relative seedling height had the greatest effect on seedling survival. Conspecific seedling density had a more negative effect on survival than heterospecific seedling density and was stronger and extended farther in rare species than in common species. Taken together, the CCT and neighborhood analyses suggest that seedling mortality is coupled more strongly to the landscape-scale abundance of conspecific large trees in common species and the local density of conspecific seedlings in rare species. We conclude that negative density dependence could promote species coexistence in this rain forest community but that the scale dependence of interactions differs between rare and common species

When a 520 million-year-old Chengjiang fossil meets a modern micro-CT - a case study

The 520 million-year-old Chengjiang biota of China (UNESCO World Heritage) presents the earliest known evidence of the so-called Cambrian Explosion. Studies, however, have mainly been limited to the information exposed on the surface of the slabs. Thus far, structures preserved inside the slabs were accessed by careful removal of the matrix, in many cases with the unfortunate sacrifice of some "less important" structures, which destroys elements of exceptionally preserved specimens. Here, we show for the first time that microtomography (micro-CT) can reveal structures situated inside a Chengjiang fossil slab without causing any damage. In the present study a trilobitomorph arthropod (Xandarella spectaculum) can be reliably identified only with the application of micro-CT. We propose that this technique is an important tool for studying three-dimensionally preserved Chengjiang fossils and, most likely, also those from other biota with a comparable type of preservation, specifically similar iron concentrations

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http://archive.org/details/determinationofc00gallN

Calibration algorithm development for selected water content reflectometers to organic soils of Alaska

Water content reflectometry is a method used by many commercial manufacturers of affordable sensors to electronically estimate soil moisture content. Field-deployable and handheld water content reflectometry probes were used in a variety of organic soil-profile types in Alaska. These probes were calibrated using 65 organic soil samples harvested from these burned and unburned, primarily moss-dominated sites in the boreal forest. Probe output was compared with gravimetrically measured volumetric moisture content, to produce calibration algorithms for surface-down-inserted handheld probes in specific soil-profile types, as well as field-deployable horizontally inserted probes in specific organic soil horizons. General organic algorithms for each probe type were also developed. Calibrations are statistically compared to determine their suitability. The resulting calibrations showed good agreement with in situvalidation and varied from the default mineral-soil-based calibrations by 20% or more. These results are of particular interest to researchers measuring soil moisture content with water content reflectometry probes in soils with high organic content

The Inter-Rater Consistency of Clinician Ratings of Posttraumatic Stress Disorder (PTSD) Therapy Content.

Effective communication between clinicians is essential for the success of mental health interventions in multidisciplinary contexts. This relies on a shared understanding of concepts, diagnoses and treatments. A major assumption of clinicians when discussing psychological treatments with each other is that both parties have a shared understanding of the theory, rationale and application of the respective technique. We aimed to determine to what extent there is inter-rater agreement between clinicians in describing the content of group therapy sessions. Pairs of clinicians, drawn from a large multidisciplinary team (13), were asked to provide ratings of the therapeutic content and emphasis of N = 154 group therapy sessions conducted during an intensive residential treatment program for post-traumatic stress disorder (PTSD). In most therapeutic content domains there was a moderate level of agreement between clinicians regarding session content (Cohen's Kappa 0.4 to 0.6), suggesting that clinicians have a broad shared understanding of therapeutic content, but that there are also frequent discordant understandings. The implications of these findings on multidisciplinary team communication, patient care and clinical handovers are discussed and directions for further research are outlined

Three-dimensional reconstruction, taphonomic and petrological data suggest that the oldest record of bioturbation is a body fossil coquina

Fossil material assigned to Nenoxites from the late Ediacaran Khatyspyt Formation of Arctic Siberia (550–544 Ma) has been presented as evidence for bioturbation prior to the basal Cambrian boundary. However, that ichnological interpretation has been challenged, and descriptions of similar material from other global localities support a body fossil origin. Here we combine x-ray computed tomography, scanning electron microscopy and petrographic methods to evaluate the body or trace fossil nature of Nenoxites from the Khatyspyt Formation. The fossilized structures consist of densely packed chains of three-dimensionally preserved silicic, bowl-shaped elements surrounded by distinct sedimentary halos, in a dolomitized matrix. Individual bowl-shaped elements can exhibit diffuse mineralogical boundaries and bridging connections between elements, both considered here to result from silicification and dolomitization during diagenesis. This new morphological and petrological evidence, in conjunction with recent studies of the late Ediacaran tubular taxa Ordinilunulatus and Shaanxilithes from China, suggest that the Khatyspyt specimens most probably reflect a coquina deposit of Shaanxilithes-like body fossils. Our data support the possibility of Shaanxilithes-like organisms representing total group eumetazoans