Chemosynthetic gas exchanger Final report, 8 Jun. 1964 - 14 Mar. 1967

Chemosynthetic bioregenerative system for long-term space exploration that employs functional coupling of water with biosynthesis by hydrogen bacteri

Light-related variation in sapling architecture of three shade-tolerant tree species of the Mexican rain forest

The crown architecture of three shade-tolerant tree species (two subcanopy and one mid-canopy) was analyzed in relation to the light regime of the forest understorey. The aim was to examine to which extent shade-tolerant species variate in their crown architecture. Tree saplings (265) between 50 and 300 cm height, and distributed from understorey to variously-sized canopy gaps, were measured for 13 architectural traits in the lowland rain forest of Los Tuxtlas, Mexico. The analysis showed that the three species changed their architecture as light increased but in a different way. No species conformed to the typical wide-crown type expected for shade-tolerant species, and in contrast they presented some traits of light demanding species. The two sub-canopy species tended to adopt a crown form between a narrow- and wide-crown type, and the mid-canopy species showed more traits of a narrow-crown type. The horizontal crown area appeared as the more related trait to the light and sapling height. It is concluded that despite being shade-tolerant, the Studied species make use of better-lit environments in the forest understorey. The crown architecture of shade-tolerant species is not Lis rigid Lis originally conceived

Seasonal variation in soil and plant water potentials in a Bolivian tropical moist and dry forest

We determined seasonal variation in soil matric potentials (¿soil) along a topographical gradient and with soil depth in a Bolivian tropical dry (1160 mm y-1 rain) and moist forest (1580 mm y-1). In each forest we analysed the effect of drought on predawn leaf water potentials (¿pd) and drought response (midday leaf water potential at a standardized ¿pd of -0.98 MPa; ¿md) of saplings of three tree species, varying in shade-tolerance and leaf phenology. ¿soil changed during the dry season and most extreme in the dry forest. Crests were drier than slopes and valleys. Dry-forest top soil was drier than deep soil in the dry season, the inverse was found in the wet season. In the moist forest the drought-deciduous species, Sweetia fruticosa, occupied dry sites. In the dry forest the short-lived pioneer, Solanum riparium, occupied wet sites and the shade-tolerant species, Acosmium cardenasii drier sites. Moist-forest species had similar drought response. The dry-forest pioneer showed a larger drought response than the other two species. Heterogeneity in soil water availability and interspecific differences in moisture requirements and drought response suggest great potential for niche differentiation. Species may coexist at different topographical locations, by extracting water from different soil layers and/or by doing so at different moments in tim

A Vector-Integration-to-Endpoint Model for Performance of Viapoint Movements

Viapoint (VP) movements are movements to a desired point that are constrained to pass through an intermediate point. Studies have shown that VP movements possess properties, such as smooth curvature around the VP, that are not explicable by treating VP movements as strict concatenations of simpler point-to-point (PTP) movements. Such properties have led some theorists to propose whole-trajectory optimization models, which imply that the entire trajectory is pre-computed before movement initiation. This paper reports new experiments conducted to systematically compare VP with PTP trajectories. Analyses revealed a statistically significant early directional deviation in VP movements but no associated curvature change. An explanation of this effect is offered by extending the Vector-Integration-To-Endpoint (VITE) model (Bullock and Grossberg, 1988), which postulates that voluntary movement trajectories emerge as internal gating signals control the integration of continuously computed vector commands based on the evolving, perceptible difference between desired and actual position variables. The model explains the observed trajectories of VP and PTP movements as emergent properties of a dynamical system that does not precompute entire trajectories before movement initiation. The new model includes a working memory and a stage sensitive to time-to-contact information. These cooperate to control serial performance. The structural and functional relationships proposed in the model are consistent with available data on forebrain physiology and anatomy.Office of Naval Research (N00014-92-J-1309, N00014-93-1-1364, N0014-95-1-0409

Environmental changes during secondary succession in a tropical dry forest in Mexico

Vegetation and environment change mutually during secondary succession, yet the idiosyncrasies of the vegetation effect on the understorey environment are poorly understood. To test whether the successional understorey environment changes predictably and is shaped by the structure and seasonality of tropical dry forests, we estimated basal area and vegetation cover, and measured understorey temperature, light and moisture conditions, in 17 plots forming a 60-y chronosequence and a mature forest. Light and air and soil temperature decreased with time (75-15% of open-sky radiation, 31.7-29.3 °C, and +2.5 °C to -0.5 °C relative to ambient, respectively), whereas relative humidity increased (67-74%). Soil water availability increased with early-successional development (-45 to -1 kPa) but decreased afterwards (to -18 kPa). The first axis of a PCA of the rainy-season environment explained 60% of the variation and was strongly related to air temperature and relative humidity. During tropical dry-forest succession, such factors may be more important than light, the reduction in which is not extreme compared with taller and more vertically stratified wet forests. Seasonality significantly affected the successional environmental gradients, which were marked mainly during the wet season. Environmental heterogeneity was higher in the wet than in the dry season, and larger for resources (light and water) than for conditions (temperature and humidity). The wet-season increase in environmental heterogeneity potentially creates differential growing scenarios; the environmental harshness of the dry season would mostly challenge seedling survival

Above-ground biomass and productivity in a rain forest of eastern South America

Abstract: The dynamics of tropical forest woody plants was studied at the Nouragues Field Station, central French Guiana. Stem density, basal area, above-ground biomass and above-ground net primary productivity, including the contribution of litterfall, were estimated from two large permanent census plots of 12 and 10 ha, established on contrasting soil types, and censused twice, first in 1992¿1994, then again in 2000¿2002. Mean stem density was 512 stems ha¿1 and basal area, 30m2 ha¿1. Stem mortality rate ranged between 1.51% and 2.06% y¿1. In both plots, stem density decreased over the study period. Using a correlation between wood density and wood hardness directly measured by a Pilodyn wood tester,we found that the mean wood densitywas 0.63 g cm¿3, 12% smaller than the mean of wood density estimated from the literature values for the species occurring in our plot. Above-ground biomass ranged from 356 to 398Mgha¿1 (oven-dry mass), and it increased over the census period. Leaf biomass was 6.47Mg ha¿1. Our total estimate of aboveground net primary productivity was 8.81 MgC ha¿1 y¿1 (in carbon units), not accounting for loss to herbivory, branchfalls, or biogenic volatile organic compounds, whichmay altogether account for an additional 1MgC ha¿1 y¿1. Coarse wood productivity (stem growth plus recruitment) contributed to 4.16 MgC ha¿1 y¿1. Litterfall contributed to 4.65MgC ha¿1 y¿1 with 3.16 MgC ha¿1 y¿1 due to leaves, 1.10 MgC ha¿1 y¿1 to twigs, and 0.39MgC ha¿1 y¿1 to fruits and flowers. The increase in above-ground biomass for both trees and lianas is consistentwith the hypothesis of a shift in the functioning of Amazonian rain forests driven by environmental changes, although alternative hypotheses such as a recovery from past disturbances cannot be ruled out at our site, as suggested by the observed decrease in stem density. Key Words: above-ground biomass, carbon, French Guiana, net primary productivity, tropical fores

Unraveling complexity in changing mental health care towards person-centered care

BackgroundMental health care (MHC) needs to shift towards person-centered care to better meet people’s individual needs. Open Dialogue (OD) is well-aligned with this perspective and brings it into practice. This study focuses on exploring the change process within a pilot project involving three MHC teams as they transition to a person-centered OD practice. Our aim is to identify and reflect on the challenges faced by MHC professionals in adopting person-centered care, and shedding light on the underlying complexity of these challenges. By gaining a better understanding of these obstacles, we hope to contribute to the adoption of the person-centered approach in MHC practice.MethodsOur research employed a qualitative design, involving a total of 14 semi-structured interviews with MHC professionals who were either trained in OD, OD trainees, or MHC professionals without OD training. To analyze the data, we utilized a hybrid approach that combined deductive – and inductive thematic analysis.ResultsWe identified four distinctive challenges: (1) understanding and knowledge transfer, (2) (inter)personal process, (3) emotional discomfort, and (4) the need for multi-stakeholder participation and support. In practice, these challenges intersect and the appearance of and relationships between these challenges are not linear or disentangleable.ConclusionUpon careful consideration of these interdependent challenges, it became evident that embedding a person-centered approach like OD brings about systemic change, leading to an unfamiliar situation X. The research findings indicated that understanding and conveying the concept of person-centered care in practical settings poses significant challenges. The field of knowledge management helps to capture the complexity of understanding and transferring this knowledge. The change process necessitates an (inter)personal process and elicits emotional discomfort, as person-centered OD practice confronts a deeply entrenched paradigm in MHC. Achieving a shared understanding of person-centered care requires dedicated time and attention, while introducing this approach prompts broader discussions on underlying values and human rights in MHC. Current implementation efforts may underestimate or overlook these underlying values, but initiating an open dialogue can serve as an initial step in addressing the complexities

Tangible landscapes and abstract narratives

© 2020 Association for Computing Machinery. The Tangible Landscapes range of interactive audiovisual and sculptural pieces offer audiences opportunities to explore abstract landscapes, recreating an embodied experience of the materials, through tangible interaction with found objects. The objects can contain sensors (tilt, orientation, movement, proximity, pressure, etc) which allow the audience to manipulate the video material through the sensors influencing the algorithms in the system. New meanings and new narratives can emerge from the audience interactions, explorations and interpretations, combining the individual and social, as well as the intimate and the spatial. Interactive art in general, and these pieces in particular, encourage and support the audience to create their own unique experiences, allowing for an individual sense of agency. The resulting patterns and images that emerge from the interaction, though these deliberate opportunities, a participative process of co-creating. This paper presents a range of these Tangible Landscape pieces, their relationship with earlier pieces and research, and placed in a context of artistic expression engaging with nature such as Landscape Art