438 research outputs found
Study to define and verify the personal oral hygiene requirements for extended manned space flight Annual report, 1 Jul. 1968 - 30 Jun. 1969
Astronaut oral hygiene requirements for extended manned space fligh
Spatial variation in short-term (234Th) sediment bioturbation intensity along an organic-carbon gradient
Natural and human-induced spatial gradients provide a useful vehicle with which to better understand diverse marine processes. On the Palos Verdes margin (S. California), historical and ongoing waste-water discharge has created an along-shelf gradient in organic C and total N, as well as various trace metals and other pollutants (e.g., DDT). To better understand the impact of such pollution on bioturbation and to develop a more general understanding of the controlling factors of sediment bioturbation intensity, a series of stations representing severely, moderately and negligibly impacted sediments was studied. Vertical profiles of the naturally occurring radionuclide, 234Th, as well as the abundance and species composition of macrofauna were measured from box cores collected at three sites during July 1992. During a March 1993 cruise, radionuclide profiles were collected at an additional eleven sites on the margin. Excess 234Th profiles are, in general, consistent with a steady-state model that balances vertical biodiffusive mixing with radioactive decay. Biodiffusivities determined from the 234Th profiles yield a spatial pattern in which sediments near the outfall are mixed at intensities of ≈10 cm2/yr, and bioturbation intensities are five times as rapid at sites 5–7 km from the outfall. Average mixing intensities are between these extremes (28 cm2/yr) at a nearby unimpacted site. Despite the overall consistency of this pattern the reasons behind it remain unclear. Structural aspects of the macrofauna either do not vary between the three intensively studied stations (e.g., depth distribution, size) or do so in a manner that would suggest an opposite effect on the biodiffusivity (e.g., abundance). There is also little variability in trophic groupings along the enrichment gradient. Behavioral modifications, such as: (1) sublethal pollution effects caused by elevated contaminant (e.g., organic carbon and DDT) concentrations, and (2) inhibition by a tube-building polychaete, Mediomastus sp., are postulated to suppress mixing intensities near the outfall. The results of this study suggest that, at least in shallow-water settings, the general controls of bioturbation intensity are still poorly understood
Effects of weather and hunting on wild reindeer population dynamics in Hardangervidda National Park
Wild reindeer have a range that extends across the circumpolar region. In the last few decades, however, populations of wild reindeer have been on the decline. The reasons for these declines are poorly understood, but are suggested to be linked to both local and global climatic factors, disease, and human interference. Hardangervidda plateau in Norway is home to the largest wild reindeer population in Europe, and is at the southern end of its European range. This population is therefore of particular importance, particularly in the light of climate change. We investigated how weather and hunting have affected the wild reindeer population in Hardangervidda over the last two decades. Our findings suggest that the wild reindeer population in Hardangervidda is most affected by winter temperature and hunting, where colder temperatures and lower harvest rates typically result in higher growth rates. We did not find significant evidence for linear density dependence. Our results show trends across Hardangervidda, and give an indication of how region-wide weather and hunting pressure can affect the wild reindeer population. As new data emerge, future investigations should look into the existence and nature of density dependence and the influence of other weather and human disturbance related factors
A mechanistic view of the particulate biodiffusion coefficient: Step lengths, rest periods and transport directions
We link specific mechanisms of biogenous sediment mixing with the commonly used bioturbation coefficient (Db) that describes their bulk effects. Using an isotropic, stationary, unbiased random walk model we mechanistically decompose the particulate bioturbation coefficient into the fundamental dimensions of length and time. The result shows that Db depends directly on the square of the distance particles are moved (step length) and inversely on the elapsed time between movements (rest period). This new decomposition in terms of explicit mechanisms (i.e., animal activities), leads to scaling arguments that large, deposit feeding animals will in nearly all cases dominate biogenous mixing. Paradoxically, such animals often transport particles vertically in an advective fashion (e.g., conveyor-belt feeding), making the widespread fit of the diffusion equation to tracer profiles equivocal. Finite-difference simulations reveal that even in the complete absence of vertical diffusion, rapid diffusive horizontal mixing coupled with vertical advection can produce vertical profiles characteristic of diffusion. We suggest that near-surface horizontal mixing rates by animals far exceed vertical mixing rates in the same stratum and that this anisotropy may persist throughout the surface mixed layer. Thus, despite their apparently good kinematic fit, one-dimensional biodiffusion coefficients may not accurately describe the dynamics of sediment displacement, leading to errors in models of early diagenesis
Visualization and chemical characterization of the cathode electrolyte interphase using He-ion microscopy and in situ time-of-flight secondary ion mass spectrometry
Unstable cathode electrolyte interphase (CEI) formation increases degradation in high voltage Li-ion battery materials. Few techniques couple characterization of nano-scale CEI layers on the macroscale with in situ chemical characterization, and thus, information on how the underlying microstructure affects CEI formation is lost. Here, the process of CEI formation in a high voltage cathode material, LiCoPO4, has been investigated for the first time using helium ion microscopy (HIM) and in situ time-of-flight (ToF) secondary ion mass spectrometry (SIMS). The combination of HIM and Ne-ion ToF-SIMS has been used to correlate the cycle-dependent morphology of the CEI layer on LiCoPO4 with a local cathode microstructure, including position, thickness, and chemistry. HIM imaging identified partial dissolution of the CEI layer on discharge resulting in in-homogenous CEI coverage on larger LiCoPO4 agglomerates. Ne-ion ToF-SIMS characterization identified oxyfluorophosphates from HF attack by the electrolyte and a Li-rich surface region. Variable thickness of the CEI layer coupled with inactive Li on the surface of LiCoPO4 electrodes contributes to severe degradation over the course of 10 cycles. The HIM–SIMS technique has potential to further investigate the effect of microstructures on CEI formation in cathode materials or solid electrolyte interphase formation in anodes, thus aiding future electrode development
High stakes lies: Police and non-police accuracy in detecting deception
This is an Accepted Manuscript of an article published by Taylor & Francis in Psychology, Crime and Law on 26 June 2014 available online: http://wwww.tandfonline.com/10.1080/1068316X.2014.935777To date, the majority of investigations in to accuracy in detecting deception have used low stakes lies as stimulus materials, and findings from these studies suggest that people are generally poor at detecting deception. The research presented here utilised real life, high stakes lies as stimulus materials, to investigate the accuracy of police and non-police observers in detecting deception. It was hypothesised that both police and non-police observers would achieve above chance levels of accuracy in detecting deception, that police officers would be more accurate at detecting deception than non-police observers, that confidence in veracity judgements would be positively related to accuracy, and that consensus judgements would predict veracity. 107 observers (70 police officers and 37 non-police participants) watched 36 videos of people lying or telling the truth in an extremely high stakes, real life situation. Police observers achieved mean accuracy in detecting deception of 72%, non-police observers achieved 68% mean accuracy, and confidence in veracity judgements were positively related to accuracy. Consensus judgements correctly predicted veracity in 92% of cases.ESRC grant number ES/I013288/
Schistosoma mansoni cercarial elastase (SmCE): differences in immunogenic properties of native and recombinant forms
The Schistosoma mansoni cercarial elastase (SmCE) has previously been shown to be poorly immunogenic in mice. However, a minority of mice were able to produce antibodies against SmCE after multiple immunizations with crude pre- parations containing the enzyme. These mice were partially protected against challenge infections of S. mansoni. In the present study, we show that in contrast to the poor immunogenicity of the enzymatically active native form of SmCE derived from a crude preparation (cercarial transformation fluid), immunization of CBA/Ca mice with two enzymatically inactive forms, namely purified native SmCE or a recombinant SmCE fused to recombinant Schistosoma japonicum gluta- thione S-transferase (rSmCE-SjGST), after adsorption onto aluminum hydroxide adjuvant, induced specific anti-SmCE immunoglobulin G (IgG) in all mice within 2 weeks of the second immunization. The IgG antibody response to rSmCE- SjGST was mainly of the IgG1 subclass. These results suggest that inactive forms of the antigen could be used to obtain the optimum immunogenic effects as a vaccine candidate against schistosomiasis. Mice immunized with the rSmCE- SjGST on alum had smaller mean worm burdens and lower tissue egg counts when compared with adjuvant alone- and recombinant SjGST-injected controls. The native SmCE was antigenically cross-reactive with homologous enzymes of Schistosoma haematobium and Schistosoma margrebowiei
Primary accumulation in the Soviet transition
The Soviet background to the idea of primary socialist accumulation is presented. The mobilisation of labour power and of products into public sector investment from outside are shown to have been the two original forms of the concept. In Soviet primary accumulation the mobilisation of labour power was apparently more decisive than the mobilisation of products. The primary accumulation process had both intended and unintended results. Intended results included bringing most of the economy into the public sector, and industrialisation of the economy as a whole. Unintended results included substantial economic losses, and the proliferation of coercive institutions damaging to attainment of the ultimate goal - the building of a communist society
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Trends in the suspended-sediment yields of coastal rivers of northern California, 1955–2010
Time-depe ndencies of suspended-sediment discharge from six coastal watersheds of northern Califor nia
– Smith River, Klamath River, Trinity River, Redwood Creek, Mad River, and Eel River –were evaluated
using monitoring data from 1955 to 2010. Suspended-sediment concentrations revealed ti me-dependent
hysteresis and multi-year trends. The multi-year trends had two primary patterns relative to river dis-
charge: (i)increases in concentration resulting from both land clearing from loggin gand the floodof
record during December 1964 (water year 1965),and (ii)continual decreases in concentration during
the decades following this flood.Data from the Eel River revealed that changes in suspended-sediment
concentrations occurred for all grain-size fractions, but were most pronounced for the sand fraction.
Because of these changes, the use of bulk discharge-concentration relationships (i.e.,‘‘sediment ratin g
curves’’) without time-dependencies in these relationships resulted in substantial errors in sediment load
estimates, including 2.5-fold over-prediction of Eel River sediment loads since 1979. We conclu de that
sedimen tdischarge and sediment discharge relationships (suchas sediment rating curves)from these
coastal rivers have varied substantially with time in response to land use and climate. Thus, the use of
historical river sediment data and sediment rating curves without considerations for time-depende nt
trends may result in significanterrors in sediment yield estimates from the globally-im portant steep,
small watersheds.Keywords: Northern California, River, Suspended-sediment discharge, Time series analysi
Novel Role of the IGF-1 Receptor in Endothelial Function and Repair: Studies in Endothelium-Targeted IGF-1 Receptor Transgenic Mice
We recently demonstrated that reducing IGF-1 receptor (IGF-1R) numbers in the endothelium enhances nitric oxide (NO) bioavailability and endothelial cell insulin sensitivity. In the present report, we aimed to examine the effect of increasing IGF-1R on endothelial cell function and repair. To examine the effect of increasing IGF-1R in the endothelium, we generated mice overexpressing human IGF-1R in the endothelium (human IGF-1R endothelium-overexpressing mice [hIGFREO]) under direction of the Tie2 promoter enhancer. hIGFREO aorta had reduced basal NO bioavailability (percent constriction to NG-monomethyl-l-arginine [mean (SEM) wild type 106% (30%); hIGFREO 48% (10%)]; P < 0.05). Endothelial cells from hIGFREO had reduced insulin-stimulated endothelial NO synthase activation (mean [SEM] wild type 170% [25%], hIGFREO 58% [3%]; P = 0.04) and insulin-stimulated NO release (mean [SEM] wild type 4,500 AU [1,000], hIGFREO 1,500 AU [700]; P < 0.05). hIGFREO mice had enhanced endothelium regeneration after denuding arterial injury (mean [SEM] percent recovered area, wild type 57% [2%], hIGFREO 47% [5%]; P < 0.05) and enhanced endothelial cell migration in vitro. The IGF-1R, although reducing NO bioavailability, enhances in situ endothelium regeneration. Manipulating IGF-1R in the endothelium may be a useful strategy to treat disorders of vascular growth and repair. Insulin-resistant type 2 diabetes characterized by perturbation of the insulin/IGF-1 system is a multisystem disorder of nutrient homeostasis, cell growth, and tissue repair (1). As a result, type 2 diabetes is a major risk factor for the development of a range of disorders of human health, including occlusive coronary artery disease (2), peripheral vascular disease (3), stroke (4), chronic vascular ulcers (5), proliferative retinopathy (6), and nephropathy (7). A key hallmark of these pathologies is endothelial cell dysfunction characterized by a reduction in bioavailability of the signaling radical nitric oxide (NO). In the endothelium, insulin binding to its tyrosine kinase receptor stimulates release of NO (8). Insulin resistance at a whole-body level (9,10) and specific to the endothelium (11) leads to reduced bioavailability of NO, indicative of a critical role for insulin in regulating NO bioavailability. The insulin receptor (IR) and IGF-1 receptor (IGF-1R) are structurally similar—both composed of two extracellular α and two transmembrane β subunits linked by disulfide bonds (12). As a result, IGF-1R and IR can heterodimerize to form insulin-resistant hybrid receptors composed of one IGF-1R-αβ complex and one IR-αβ subunit complex (13,14). We recently demonstrated that reducing IGF-1R (by reducing the number of hybrid receptors) enhances insulin sensitivity and NO bioavailability in the endothelium (15). To examine the effect of increasing IGF-1R specifically in the endothelium on NO bioavailability, endothelial repair, and metabolic homeostasis, we generated a transgenic mouse with targeted overexpression of the human IGF-1R in the endothelium (hIGFREO)
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