Hall current accelerator Final report, 10 Jun. 1964 - 10 Sep. 1965

Axisymmetric Hall current accelerator as electric spacecraft propulsion syste

Cementitious grouts for intermediate level nuclear waste (ILW) encapsulation - effect of compositional changes upon hydration

Grouts containing high levels of replacement by BFS are the preferred route to disposal for a large majority of ILW in the UK. A number of techniques, SEM image analysis, chemical shrinkage, ICC, TGA and XRD, have been applied to assess the rate and degree of hydration of such cementitious grouts. This study forms a base for quantifying the effects of modifications to the physical and chemical composition of both the OPC and the BFS components of the matrix in order to identify the sensitivity or otherwise of the technique to ensure that a continuity of supply is maintained

Mitochondrial Dna Replacement Versus Nuclear Dna Persistence

In this paper we consider two populations whose generations are not overlapping and whose size is large. The number of males and females in both populations is constant. Any generation is replaced by a new one and any individual has two parents for what concerns nuclear DNA and a single one (the mother) for what concerns mtDNA. Moreover, at any generation some individuals migrate from the first population to the second. In a finite random time $T$, the mtDNA of the second population is completely replaced by the mtDNA of the first. In the same time, the nuclear DNA is not completely replaced and a fraction $F$ of the ancient nuclear DNA persists. We compute both $T$ and $F$. Since this study shows that complete replacement of mtDNA in a population is compatible with the persistence of a large fraction of nuclear DNA, it may have some relevance for the Out of Africa/Multiregional debate in Paleoanthropology

Effect of Particle Size on Droplet Infiltration into Hydrophobic Porous Media As a Model of Water Repellent Soil

The wettability of soil is of great importance for plants and soil biota, and in determining the risk for preferential flow, surface runoff, flooding,and soil erosion. The molarity of ethanol droplet (MED) test is widely used for quantifying the severity of water repellency in soils that show reduced wettability and is assumed to be independent of soil particle size. The minimum ethanol concentration at which droplet penetration occurs within a short time (≤10 s) provides an estimate of the initial advancing contact angle at which spontaneous wetting is expected. In this study, we test the assumption of particle size independence using a simple model of soil, represented by layers of small (0.2–2 mm) diameter beads that predict the effect of changing bead radius in the top layer on capillary driven imbibition. Experimental results using a three-layer bead system show broad agreement with the model and demonstrate a dependence of the MED test on particle size. The results show that the critical initial advancing contact angle for penetration can be considerably less than 90° and varies with particle size, demonstrating that a key assumption currently used in the MED testing of soil is not necessarily valid

Vascular endothelial growth factor-D over-expressing tumor cells induce differential effects on uterine vasculature in a mouse model of endometrial cancer

BACKGROUND: It has been hypothesised that increased VEGF-D expression may be an independent prognostic factor for endometrial cancer progression and lymph node metastasis; however, the mechanism by which VEGF-D may promote disease progression in women with endometrial cancer has not been investigated. Our aim was to describe the distribution of lymphatic vessels in mouse uterus and to examine the effect of VEGF-D over-expression on these vessels in a model of endometrial cancer. We hypothesised that VEGF-D over-expression would stimulate growth of new lymphatic vessels into the endometrium, thereby contributing to cancer progression. METHODS: We initially described the distribution of lymphatic vessels (Lyve-1, podoplanin, VEGFR-3) and VEGF-D expression in the mouse uterus during the estrous cycle, early pregnancy and in response to estradiol-17beta and progesterone using immunohistochemistry. We also examined the effects of VEGF-D over-expression on uterine vasculature by inoculating uterine horns in NOD SCID mice with control or VEGF-D-expressing 293EBNA tumor cells. RESULTS: Lymphatic vessels positive for the lymphatic endothelial cell markers Lyve-1, podoplanin and VEGFR-3 profiles were largely restricted to the connective tissue between the myometrial circular and longitudinal muscle layers; very few lymphatic vessel profiles were observed in the endometrium. VEGF-D immunostaining was present in all uterine compartments (epithelium, stroma, myometrium), although expression was generally low. VEGF-D immunoexpression was slightly but significantly higher in estrus relative to diestrus; and in estradiol-17beta treated mice relative to vehicle or progesterone treated mice. The presence of VEGF-D over-expressing tumor cells did not induce endometrial lymphangiogenesis, although changes were observed in existing vessel profiles. For myometrial lymphatic and endometrial blood vessels, the percentage of profiles containing proliferating endothelial cells, and the cross sectional area of vessel profiles were significantly increased in response to VEGF-D in comparison to control tumor cells. In contrast, no significant changes were noted in myometrial blood vessels. In addition, examples of invading cells or tumor emboli were observed in mice receiving VEGF-D expressing 293EBNA cells. CONCLUSIONS: These results illustrate that VEGF-D over-expression has differential effects on the uterine vasculature. These effects may facilitate VEGF-D's ability to promote endometrial cancer metastasis and disease progression

Hydrous Carbonatitic Liquids Drive CO2 Recycling From Subducted Marls and Limestones

This research was supported by the Italian Ministry of Education, University, and Research (MIUR) program PRIN2017 and by the Deep Carbon Observatory (DCO). We are greatly indebted to Andrea Risplendente for careful examination of run charges at the Electron Microprobe.Pelagic limestones are subducted in a variety of subduction zones worldwide. Despite the geochemical relevance of systems enriched in CaCO3, previous experimental investigations mostly focused on carbonated pelites, with low Ca/(Ca+Mg+Fe) ratio. We present the compositions and the formation conditions of liquids in the model system CaO‐Al2O3‐SiO2‐H2O‐CO2 (CASHC), building on phase relationships in the subsystems CHC and CSHC, where a second critical endpoint was suggested at temperatures as low as 515 °C, and 3.2 GPa. Multianvil experiments were performed at 4.2 and 6.0 GPa on five bulk compositions at variable Ca/Si/Al ratios. H2O contents vary from 5.6 to 21 wt%. Aragonite + kyanite + vapor and minor lawsonite form at 700 °C, replaced by zoisite/grossular at 800 °C. Between 850 °C and 950 °C, a complex sequence of textural features is observed upon quenching of a single volatile‐rich liquid phase formed at run conditions. Precipitates include dendritic CaCO3, silicate glass, and Al‐rich whiskers. The bulk composition of such hydrous carbonatitic liquids is retrieved by image analysis on X‐ray maps, showing Ca/Si ratio increasing with pressure and temperature. Hydrous Ca‐carbonatitic liquids are efficient media for scavenging volatiles from subducted crustal material and for metasomatizing the mantle wedge.Ministry of Education, Universities and Research (MIUR)Deep Carbon Observatory (DCO

Epidemic space

The aim of this article is to highlight the importance of 'spatiality' in understanding the materialization of risk society and cultivation of risk sensibilities. More specifically it provides a cultural analysis of pathogen virulence (as a social phenomenon) by means of tracing and mapping the spatial flows that operate in the uncharted zones between the microphysics of infection and the macrophysics of epidemics. It will be argued that epidemic space consists of three types of forces: the vector, the index and the vortex. It will draw on Latour's Actor Network Theory to argue that epidemic space is geared towards instability when the vortex (of expanding associations and concerns) displaces the index (of finding a single cause)

The Genetic Structure and History of Africans and African Americans.

Africa is the source of all modern humans, but characterization of genetic variation and of relationships among populations across the continent has been enigmatic. We studied 121 African populations, four African American populations, and 60 non-African populations for patterns of variation at 1327 nuclear microsatellite and insertion/deletion markers. We identified 14 ancestral population clusters in Africa that correlate with self-described ethnicity and shared cultural and/or linguistic properties. We observed high levels of mixed ancestry in most populations, reflecting historical migration events across the continent. Our data also provide evidence for shared ancestry among geographically diverse hunter-gatherer populations (Khoesan speakers and Pygmies). The ancestry of African Americans is predominantly from Niger-Kordofanian (approximately 71%), European (approximately 13%), and other African (approximately 8%) populations, although admixture levels varied considerably among individuals. This study helps tease apart the complex evolutionary history of Africans and African Americans, aiding both anthropological and genetic epidemiologic studies