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

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

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

Shared reading of children's interactive picture books

We report on a study of children and parents shared reading of interactive printed books. We investigated the differences between books with interactive features and books with expressive typography in order to evaluate which features within a book encouraged interaction between the reading participants and the book. 11 parent and child groups took part in the study that involved three observed reading sessions. From our observations we offer suggestions for the development of books and eBooks to encourage shared reading practices

Orbital and spin physics in LiNiO2 and NaNiO2

We derive a spin-orbital Hamiltonian for a triangular lattice of e_g orbital degenerate (Ni^{3+}) transition metal ions interacting via 90 degree superexchange involving (O^{2-}) anions, taking into account the on-site Coulomb interactions on both the anions and the transition metal ions. The derived interactions in the spin-orbital model are strongly frustrated, with the strongest orbital interactions selecting different orbitals for pairs of Ni ions along the three different lattice directions. In the orbital ordered phase, favoured in mean field theory, the spin-orbital interaction can play an important role by breaking the U(1) symmetry generated by the much stronger orbital interaction and restoring the threefold symmetry of the lattice. As a result the effective magnetic exchange is non-uniform and includes both ferromagnetic and antiferromagnetic spin interactions. Since ferromagnetic interactions still dominate, this offers yet insufficient explanation for the absence of magnetic order and the low-temperature behaviour of the magnetic susceptibility of stoichiometric LiNiO_2. The scenario proposed to explain the observed difference in the physical properties of LiNiO_2 and NaNiO_2 includes small covalency of Ni-O-Li-O-Ni bonds inducing weaker interplane superexchange in LiNiO_2, insufficient to stabilize orbital long-range order in the presence of stronger intraplane competition between superexchange and Jahn-Teller coupling.Comment: 33 pages, 12 postscript figures, uses iopams.sty . This article features in New Journal of Physics as part of a Focus Issue on Orbital Physics - all contributions may be freely accessed at (http://stacks.iop.org/1367-2630/6/i=1/a=E05). The published version of this article may be found at http://stacks.iop.org/1367-2630/7/12

One is not the other:Predicting offending after discharge from secure residential care of male adolescents with four risk profiles

Purpose: Adolescents who are admitted to secure residential care have a high risk of delinquency after discharge. However, this risk may differ between subgroups in this heterogeneous population of adolescents with severe psychiatric problems and disruptive problem behaviour. In this study, the predictive validity of four risk profiles was examined for the number of minor, moderate, and severe offences after discharge from secure residential care.Methods: The sample comprised 238 male former patients of a hospital for youth forensic psychiatry and orthopsychiatry in the Netherlands. In three Poisson regression analyses, the relationship between four previously identified risk profiles and the number of minor, moderate, and severe offences after discharge was examined.Results: The results showed that the four risk profiles differed significantly in the number of minor, moderate, and severe offences after discharge. Post hoc analysis revealed no mediating effect of termination of treatment on the relationship between the risk profiles and the number of minor, moderate, and severe offending after discharge.Conclusion: Adolescents with many risk factors in multiple domains and adolescents with mainly family risks have an increased risk of persistent delinquency after discharge. Treatment should be tailored more effectively to the specific risks and needs of these adolescents

The trajectory of caregiver burden and risk factors in dementia progression:A systematic review

Background: Caring for patients with dementia at home is often a long-term process, in which the independence of the patient declines, and more responsibility and supervision time is required from the informal caregiver. Objective: In order to minimize and reduce caregiver burden, it is important to explore its trajectory and the accompanying risk factors as dementia progresses; the objective of this systematic review. Methods: PRISMA guidelines were followed in this systematic review. Three databases, PubMed, PsycINFO, and EMbase, were systematically searched in November 2019 using specific keywords. Results: 1,506 hits emerged during the systematic search but only eleven articles actually met the inclusion criteria for this review. The trajectory of caregiver burden is highly variable and depends on multiple factors. Important risk factors included: patients’ behavioral and neuropsychiatric symptoms, and their decline in functioning in (I)ADL; the caregiver’s age, gender, and physical and mental health; and, within the dyads (patient/caregiver), cohabitation and kinship. Conclusion: There is no one-size-fits-all for predicting how caregiver burden will change over time, but specific factors (like being a spouse and increased behavioral impairment and decline in functional status in the patient) may heighten the risk. Other factors, not yet comprehensively included in the published studies, might also prove to be important risk factors. Future research in the field of reducing caregiver burden is recommended to integrate the patient, caregiver, and context characteristics in the trajectory of caregiver burden, and to assess more clearly the phase of the dementia progression and use of external resources

Predicting protein decomposition: the case of aspartic-acid racemization kinetics

The increase in proportion of the non-biological (D-) isomer of aspartic acid (Asp) relative to the L- isomer has been widely used in archaeology and geochemistry as a tool for dating. The method has proved controversial, particularly when used for bones. The non-linear kinetics of Asp racemization have prompted a number of suggestions as to the underlying mechanism(s) and have led to the use of mathe- matical transformations which linearize the increase in D-Asp with respect to time. Using one example, a suggestion that the initial rapid phase of Asp racemization is due to a contribution from asparagine (Asn), we demonstrate how a simple model of the degradation and racemization of Asn can be used to predict the observed kinetics. A more complex model of peptide bound Asx (Asn+Asp) racemization, which occurs via the formation of a cyclic succinimide (Asu), can be used to correctly predict Asx racemi- zation kinetics in proteins at high temperatures (95-140 °C). The model fails to predict racemization kinetics in dentine collagen at 37 °C. The reason for this is that Asu formation is highly conformation dependent and is predicted to occur extremely slowly in triple helical collagen. As conformation strongly in£uences the rate of Asu formation and hence Asx racemization, the use of extrapolation from high temperatures to estimate racemization kinetics of Asx in proteins below their denaturation temperature is called into question. In the case of archaeological bone, we argue that the D:L ratio of Asx re£ects the proportion of non- helical to helical collagen, overlain by the e¡ects of leaching of more soluble (and conformationally unconstrained) peptides. Thus, racemization kinetics in bone are potentially unpredictable, and the proposed use of Asx racemization to estimate the extent of DNA depurination in archaeological bones is challenged

Second generation endometrial ablation techniques for heavy menstrual bleeding: network meta-analysis

Objective To determine the relative effectiveness of second generation ablation techniques in the treatment of heavy menstrual bleeding