Injection of meteoric phosphorus into planetary atmospheres

This study explores the delivery of phosphorus to the upper atmospheres of Earth, Mars, and Venus via the ablation of cosmic dust particles. Micron-size meteoritic particles were flash heated to temperatures as high as 2900 ​K in a Meteor Ablation Simulator (MASI), and the ablation of PO and Ca recorded simultaneously by laser induced fluorescence. Apatite grains were also ablated as a reference. The speciation of P in anhydrous chondritic porous Interplanetary Dust Particles was made by K-edge X-ray absorption near edge structure (XANES) spectroscopy, demonstrating that P mainly occurs in phosphate-like domains. A thermodynamic model of P in a silicate melt was then developed for inclusion in the Leeds Chemical Ablation Model (CABMOD). A Regular Solution model used to describe the distribution of P between molten stainless steel and a multicomponent slag is shown to provide the most accurate solution for a chondritic-composition, and reproduces satisfactorily the PO ablation profiles observed in the MASI. Meteoritic P is moderately volatile and ablates before refractory metals such as Ca; its ablation efficiency in the upper atmosphere is similar to Ni and Fe. The speciation of evaporated P depends significantly on the oxygen fugacity, and P should mainly be injected into planetary upper atmospheres as PO2, which will then likely undergo dissociation to PO (and possibly P) through hyperthermal collisions with air molecules. The global P ablation rates are estimated to be 0.017 ​t ​d−1 (tonnes per Earth day), 1.15 ​× ​10−3 ​t ​d−1 and 0.024 ​t ​d−1 for Earth, Mars and Venus, respectively

Impacts of Cosmic Dust on Planetary Atmospheres and Surfaces

Recent advances in interplanetary dust modelling provide much improved estimates of the fluxes of cosmic dust particles into planetary (and lunar) atmospheres throughout the solar system. Combining the dust particle size and velocity distributions with new chemical ablation models enables the injection rates of individual elements to be predicted as a function of location and time. This information is essential for understanding a variety of atmospheric impacts, including: the formation of layers of metal atoms and ions; meteoric smoke particles and ice cloud nucleation; perturbations to atmospheric gas-phase chemistry; and the effects of the surface deposition of micrometeorites and cosmic spherules. There is discussion of impacts on all the planets, as well as on Pluto, Triton and Titan

Thoracic costotransverse joint pain patterns: a study in normal volunteers

<p>Abstract</p> <p>Background</p> <p>Pain referral patterns of asymptomatic costotransverse joints have not been established. The objective of this study was to determine the pain referral patterns of asymptomatic costotransverse joints via provocative intra-articular injection.</p> <p>Methods</p> <p>Eight asymptomatic male volunteers received a combined total of 21 intra-articular costotransverse joint injections. Fluoroscopic imaging was used to identify and isolate each costotransverse joint and guide placement of a 25 gauge, 2.5 inch spinal needle into the costotransverse joint. Following contrast medium injection, the quality, intensity, and distribution of the resultant pain produced were recorded.</p> <p>Results</p> <p>Of the 21 costotransverse joint injections, 16 (76%) were classified as being intra-articular via arthrograms taken at the time of injection, and 14 of these injections produced a pain sensation distinctly different from that of needle placement. Average pain produced was 3.3/10 on a 0–10 verbal pain scale. Pain was described generally as a deep, dull ache, and pressure sensation. Pain patterns were located superficial to the injected joint, with only the right T2 injections showing referred pain 2 segments cranially and caudally. No chest wall, upper extremity or pseudovisceral pains were reported.</p> <p>Conclusion</p> <p>This study provides preliminary data of the pain referral patterns of costotransverse joints. Further research is needed to compare these findings with those elicited from symptomatic subjects.</p

Delivery of Complex Organic Compounds from Evolved Stars to the Solar System

Stars in the late stages of evolution are able to synthesize complex organic compounds with aromatic and aliphatic structures over very short time scales. These compounds are ejected into the interstellar medium and distributed throughout the Galaxy. The structures of these compounds are similar to the insoluble organic matter found in meteorites. In this paper, we discuss to what extent stellar organics has enriched the primordial Solar System and possibly the early Earth

Longitudinal impact of a youth tobacco education program

BACKGROUND: Information on the effectiveness of elementary school level, tobacco-use prevention programs is generally limited. This study assessed the impact of a structured, one-time intervention that was designed to modify attitudes and knowledge about tobacco. Participants were fifth-grade students from schools in western New York State. METHODS: Twenty-eight schools, which were in relatively close geographic proximity, were randomized into three groups; Group 1 was used to assess whether attitudes/knowledge were changed in the hypothesized direction by the intervention, and if those changes were retained four months later. Groups 2 and 3, were used as comparison groups to assess possible test-retest bias and historical effects. Groups 1 and 3 were pooled to assess whether attitudes/knowledge were changed by the intervention as measured by an immediate post-test. The non-parametric analytical techniques of Wilcoxon-Matched Pairs/Sign Ranks and the Mann-Whitney-Wilcoxon Rank Sums Tests were used to compare proportions of correct responses at each of the schools. RESULTS: Pooled analyses showed that short-term retention on most items was achieved. It was also found that retention on two knowledge items 'recognition that smokers have yellow teeth and fingers' and 'smoking one pack of cigarettes a day costs several hundred dollars per year' was maintained for four months. CONCLUSIONS: The findings suggest that inexpensive, one-time interventions for tobacco-use prevention can be of value. Changes in attitudes and knowledge conducive to the goal of tobacco-use prevention can be achieved for short-term retention and some relevant knowledge items can be retained for several months

Assessing Natural Resource Use by Forest-Reliant Communities in Madagascar Using Functional Diversity and Functional Redundancy Metrics

Biodiversity plays an integral role in the livelihoods of subsistence-based forest-dwelling communities and as a consequence it is increasingly important to develop quantitative approaches that capture not only changes in taxonomic diversity, but also variation in natural resources and provisioning services. We apply a functional diversity metric originally developed for addressing questions in community ecology to assess utilitarian diversity of 56 forest plots in Madagascar. The use categories for utilitarian plants were determined using expert knowledge and household questionnaires. We used a null model approach to examine the utilitarian (functional) diversity and utilitarian redundancy present within ecological communities. Additionally, variables that might influence fluctuations in utilitarian diversity and redundancy—specifically number of felled trees, number of trails, basal area, canopy height, elevation, distance from village—were analyzed using Generalized Linear Models (GLMs). Eighteen of the 56 plots showed utilitarian diversity values significantly higher than expected. This result indicates that these habitats exhibited a low degree of utilitarian redundancy and were therefore comprised of plants with relatively distinct utilitarian properties. One implication of this finding is that minor losses in species richness may result in reductions in utilitarian diversity and redundancy, which may limit local residents' ability to switch between alternative choices. The GLM analysis showed that the most predictive model included basal area, canopy height and distance from village, which suggests that variation in utilitarian redundancy may be a result of local residents harvesting resources from the protected area. Our approach permits an assessment of the diversity of provisioning services available to local communities, offering unique insights that would not be possible using traditional taxonomic diversity measures. These analyses introduce another tool available to conservation biologists for assessing how future losses in biodiversity will lead to a reduction in natural resources and provisioning services from forests

A trematode parasite derived growth factor binds and exerts influences on host immune functions via host cytokine receptor complexes

The trematode Fasciola hepatica is responsible for chronic zoonotic infection globally. Despite causing a potent T-helper 2 response, it is believed that potent immunomodulation is responsible for rendering this host reactive non-protective host response thereby allow- ing the parasite to remain long-lived. We have previously identified a growth factor, FhTLM, belonging to the TGF superfamily can have developmental effects on the parasite. Herein we demonstrate that FhTLM can exert influence over host immune functions in a host receptor specific fashion. FhTLM can bind to receptor members of the Transforming Growth Factor (TGF) superfamily, with a greater affinity for TGF-β RII. Upon ligation FhTLM initiates the Smad2/3 pathway resulting in phenotypic changes in both fibroblasts and macrophages. The formation of fibroblast CFUs is reduced when cells are cultured with FhTLM, as a result of TGF-β RI kinase activity. In parallel the wound closure response of fibroblasts is also delayed in the presence of FhTLM. When stimulated with FhTLM blood monocyte derived macrophages adopt an alternative or regulatory phenotype. They express high levels interleukin (IL)-10 and arginase-1 while displaying low levels of IL-12 and nitric oxide. Moreover they also undergo significant upregulation of the inhibitory recep- tor PD-L1 and the mannose receptor. Use of RNAi demonstrates that this effect is depen- dent on TGF-β RII and mRNA knock-down leads to a loss of IL-10 and PD-L1. Finally, we demonstrate that FhTLM aids newly excysted juveniles (NEJs) in their evasion of antibody- dependent cell cytotoxicity (ADCC) by reducing the NO response of macrophages—again dependent on TGF-β RI kinase. FhTLM displays restricted expression to the F. hepatica gut resident NEJ stages. The altered fibroblast responses would suggest a role for damp- ened tissue repair responses in facilitating parasite migration. Furthermore, the adoption of a regulatory macrophage phenotype would allow for a reduced effector response targetingjuvenile parasites which we demonstrate extends to an abrogation of the ADCC response. Thus suggesting that FhTLM is a stage specific evasion molecule that utilises host cytokine receptors. These findings are the first to clearly demonstrate the interaction of a helminth cytokine with a host receptor complex resulting in immune modifications that facilitate the non-protective chronic immune response which is characteristic of F. hepatica infection

Is annual surveillance of all treated hypothyroid patients necessary?

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