In search of late-stage planetary building blocks

Genetic contributions to the final stages of planetary growth, including materials associated with the giant Moon forming impact, late accretion, and late heavy bombardment are examined using siderophile elements. Isotopic similarities between the Earth and Moon for both lithophile and siderophile elements collectively lead to the suggestion that the genetics of the building blocks for Earth, and the impactor involved in the Moon-forming event were broadly similar, and shared some strong genetic affinities with enstatite chondrites. The bulk genetic fingerprint of materials subsequently added to Earth by late accretion, defined as the addition of ~0.5 wt.% of Earth's mass to the mantle, following cessation of core formation, was characterized by 187Os/188Os and Pd/Ir ratios that were also similar to those in some enstatite chondrites. However, the integrated fingerprint of late accreted matter differs from enstatite chondrites in terms of the relative abundances of certain other HSE, most notably Ru/Ir. The final ≤0.05 wt.% addition of material to the Earth and Moon, believed by some to be part of a late heavy bombardment, included a component with much more fractionated relative HSE abundances than evidenced in the average late accretionary component. Heterogeneous 182W/184Wisotopic compositions of some ancient terrestrial rocks suggest that some very early formed mantle domains remained chemically distinct for long periods of time following primary planetary accretion. This evidence for sluggish mixing of the early mantle suggests that if late accretionary contributions to the mantle were genetically diverse, it may be possible to isotopically identify the disparate primordial components in the terrestrial rock record using the siderophile element tracers Ru and Mo.NASA grants NNX13AF83G and NNA14AB07A NSF-CSEDI grants EAR1160728 and EAR1265169

Psychosocial impact of undergoing prostate cancer screening for men with BRCA1 or BRCA2 mutations.

OBJECTIVES: To report the baseline results of a longitudinal psychosocial study that forms part of the IMPACT study, a multi-national investigation of targeted prostate cancer (PCa) screening among men with a known pathogenic germline mutation in the BRCA1 or BRCA2 genes. PARTICPANTS AND METHODS: Men enrolled in the IMPACT study were invited to complete a questionnaire at collaborating sites prior to each annual screening visit. The questionnaire included sociodemographic characteristics and the following measures: the Hospital Anxiety and Depression Scale (HADS), Impact of Event Scale (IES), 36-item short-form health survey (SF-36), Memorial Anxiety Scale for Prostate Cancer, Cancer Worry Scale-Revised, risk perception and knowledge. The results of the baseline questionnaire are presented. RESULTS: A total of 432 men completed questionnaires: 98 and 160 had mutations in BRCA1 and BRCA2 genes, respectively, and 174 were controls (familial mutation negative). Participants' perception of PCa risk was influenced by genetic status. Knowledge levels were high and unrelated to genetic status. Mean scores for the HADS and SF-36 were within reported general population norms and mean IES scores were within normal range. IES mean intrusion and avoidance scores were significantly higher in BRCA1/BRCA2 carriers than in controls and were higher in men with increased PCa risk perception. At the multivariate level, risk perception contributed more significantly to variance in IES scores than genetic status. CONCLUSION: This is the first study to report the psychosocial profile of men with BRCA1/BRCA2 mutations undergoing PCa screening. No clinically concerning levels of general or cancer-specific distress or poor quality of life were detected in the cohort as a whole. A small subset of participants reported higher levels of distress, suggesting the need for healthcare professionals offering PCa screening to identify these risk factors and offer additional information and support to men seeking PCa screening

The NC-CC Isotope Dichotomy: Implications for the Chemical and Isotopic Evolution of the Early Solar System

International audienceUnderstanding the formation of our planetary system requires identification of the materials from which it originated and the accretion processes that produced the planets. The compositional evolution of the solar system can be constrained by synthesizing astronomical datasets and numerical models with elemental and isotopic compositions from objects that directly sampled the disk: meteorites and their constituents (chondrules, refractory inclusions, and matrix). This contribution reviews constraints on early solar system evolution provided by the so-called non-carbonaceous (NC) and carbonaceous chondrite (CC) groups and their relationship to the volatile element characteristics of chondritic meteorites. In previous work, the NC or CC character of a parent body was used to infer its accretion location in the protoplanetary disk. The NC groups purportedly originated in the inner disk, and the CC groups were derived from the outer disk, where the NC and CC regions of the disk may have been separated early on by proto-Jupiter, a pressure maximum, or a dust trap in the disk. The tenet that all CC parent bodies accreted in the outer disk is, in part, based on evidence that a handful of CC meteorites are enriched in volatile species compared to NC meteorites. Here, it is reviewed if and how the volatile element and nucleosynthetic isotope compositions of meteorites can be linked to accretion locations within the disk. The nucleosynthetic isotope compositions of whole rock meteorite samples contrast the trends found for their major volatile element compositions (i.e., C, N, and O). Although there may be an increase in volatile abundances when comparing some stony NC and CC meteorites and their inferred accretion locations within the disk, this is not necessarily a general rule. The difficulties with inferring parent body accretion locations are discussed. It is found that it cannot always be assumed that parent bodies which formed in the CC reservoir are "volatile-rich" relative to those that formed in the NC reservoir which are "volatilepoor". Consequently, tracing the origin of terrestrial volatiles using the NC-CC isotope dichotomy remains challenging

Geochemical Constraints on the Origin of the Moon and Preservation of Ancient Terrestrial Heterogeneities

International audienceThe Moon forming giant impact marks the end of the main stage of Earth’s accretion and sets the stage for thesubsequent evolution of our planet. The giant impact theory has been the accepted model of lunar origin for 40 years,but the parameters of the impact and the mechanisms that led to the formation of the Moon are still hotly debated.Here we review the principal geochemical observations that constrain the timing and parameters of the impact, themechanisms of lunar formation, and the contemporaneous evolution of Earth. We discuss how chemical and isotopicstudies on lunar, terrestrial and meteorite samples relate to physical models and how they can be used to differentiatebetween lunar origin models. In particular, we argue that the efficiency of mixing during the collision is a key test of giantimpact models. A high degree of intra-impact mixing is required to explain the isotopic similarity between the Earthand Moon but, at the same time, the impact did not homogenize the whole terrestrial mantle, as isotopic signatures ofpre-impact heterogeneity are preserved. We summarize the outlook for the field and highlight the key advances in bothmeasurements and modeling needed to advance our understanding of lunar origin

The effects of Diet A or Diet B on faecal microbial diversity in pregnant queens (<i>Felis catus</i>).

<p>The rarefaction curves based on the Chao1 diversity index (at 97% sequence identity cut-off) indicate that faecal bacterial communities of cats fed Diet A (---; n =  3 cats) were less diverse than those of cats fed Diet B (–; n = 4 cats). Data are reported as means ± SEM.</p

Principal Coordinate Analysis plot of unweighted Unifrac phylogenetic distances showing the similarities between bacterial communities of queens fed Diet A or Diet B and their offspring fed Diet A (B-A or A-A) or Diet B (B-B or A-B) post-weaning.

<p>Percentage of variation captured by each component indicated on axes.</p

Principal Coordinate Analysis plot of weighted Unifrac phylogenetic distances showing the similarities between bacterial communities of queens fed Diet A or Diet B and their offspring fed Diet A (B-A or A-A) or Diet B (B-B or A-B) post-weaning.

<p>Percentage of variation captured by each component indicated on axes.</p

Macronutrient profile of a commercially available Association of American Feed Control Officials (AAFCO) feed tested maintenance diets fed to domestic short hair kittens (<i>Felis catus</i>).

1<p>Ingredient list of Diet A (from pack): Corn, chicken and chicken meal, chicken digest, maize gluten, chicken tallow, tuna meal, poultry and poultry meal, iodinised salt, vegetable oil.</p>2<p>Ingredient list of Diet B (from pack): Meat by-products and meat derived from chicken, lamb, beef, and mutton; gelling agent; minerals; vegetable oil, emulsifier; colouring; vitamins, chelating agents.</p>3<p>Nitrogen free extractables calculated by difference (100 - crude protein - crude fat - crude fibre - ash).</p>4<p>Determined using modified Atwater factors of: crude protein (3·5 kcal ME/g DM), crude fat (8·5 kcal ME/g DM), NFE (3·5 kcal ME/g DM).</p

The effects of pre-weaning (gestation and lactation) or post-weaning diets (Diet A or Diet B) on blood and tissue gene expression levels (relative fluorescence units) in the domestic kitten (<i>Felis catus</i>).

<p>Diet A-Diet A (A-A) n = 3 females, n = 2 males.</p><p>Diet A- Diet B (A-B) n = 3 females, n = 2 males.</p><p>Diet B- Diet A (B-A) n = 3 females, n = 2 males.</p><p>Diet B- Diet B (B-B) n = 4 females, n = 1 male.</p>1<p>Fatty acid synthase (FASN), Glucose transporter 1 (Glut1) and 4 (Glut4), insulin receptor (INSR), insulin receptor substrate 1 (IRS1) and 2 (IRS2), Leptin (LEPT), Hormone sensitive lipase (LIPE), plasminogen activator inhibitor-1 (PAL1), Uncoupling protein 2 (UCP2), peroxisome proliferative activated receptor-γ (PPARG).</p>2<p>Comparisons between Diets A-A and A-B vs B-A and B-B.</p>3<p>Comparison between Diets A-A and B-A and B-B and A-B.</p>4<p>n = 5 per treatment.</p>5.<p>n = 4 per treatment.</p>6<p>Ovarian or testicular tissue.</p><p>Results are presented as means ± SEM. <i>P</i> indicates ANOVA significance of rank transformed data and <i>FDR</i> indicates multiple testing adjusted <i>P</i> value. No effect of gender was observed.</p