Correlations and zoning patterns of phosphorus and chromium in olivine from H chondrites and the LL chondrite Semarkona

Phosphorus zoning is observed in olivines in high-FeO (type IIA) chondrules in H chondrites over the entire range of petrologic grades: H3.1–H6. Features in P concentrations such as oscillatory and sector zoning, and high P cores are present in olivines that are otherwise unzoned in the divalent cations. Aluminum concentrations are low and not significantly associated with P zoning in chondrule olivines. In highly unequilibrated H chondrites, phosphorus zoning is generally positively correlated with Cr. Atomic Cr:P in olivine is roughly 1:1 (3:1 for one zone in one olivine in RC 075), consistent with Cr^(3+) charge-balancing P^(5+) substituting for Si^(4+). Normal igneous zonation involving the dominant chrome species Cr^(2+) was observed only in the LL3.0 chondrite Semarkona. In more equilibrated chondrites (H3.5–H3.8), Cr spatially correlated with P is occasionally observed but it is diffuse relative to the P zones. In H4–H6 chondrites, P-correlated Cr is absent. One signature of higher metamorphic grades (≥H3.8) is the presence of near matrix olivines that are devoid of P oscillatory zoning. The restriction to relatively high metamorphic grade and to grains near the chondrule–matrix interface suggests that this is a response to metasomatic processes. We also observed P-enriched halos near the chondrule–matrix interface in H3.3–H3.8 chondrites, likely reflecting the loss of P and Ca from mesostasis and precipitation of Ca phosphate near the chondrule surface. These halos are absent in equilibrated chondrites due to coarsening of the phosphate and in unequilibrated chondrites due to low degrees of metasomatism. Olivines in type IA chondrules show none of the P-zoning ubiquitous in type IIA chondrules or terrestrial igneous olivines, likely reflecting sequestration of P in reduced form within metallic alloys and sulfides during melting of type IA chondrules

Zoning patterns of Fe and V in spinel from a type B Ca-Al-rich inclusion: Constraints on subsolidus thermal history

We obtained two-dimensional concentration maps for the minor elements Fe and V in 21 spinel crystals in the Allende type B1 inclusion TS-34 with a 4–5 μm resolution. Locally high concentrations of Fe occur along at least one edge of the spinels and decrease toward the center of the grains. Enrichment in V can also occur along edges or at corners. In general, there is no overall correlation of the Fe and V distributions, but in local regions of two grains, the V and Fe distributions are correlated, strongly suggesting a local source for both elements. In these two grains, opaque assemblages are present that appear to locally control the V distributions. This, coupled with previous work, suggests that prior to alteration, TS-34 contained V-rich metal. Oxidation of this metal during alteration can account for the edge/corner V enrichments, but provide only minor FeO contributions, explaining the overall lack of correlation between Fe and V. Most of the FeO appears to have been externally introduced along spinel boundaries during alteration. These alteration phases served as sources for diffusion of FeO into spinel. FeO distributions in spinel lead to a mean attenuation length of ~8 μm and, using literature diffusion coefficients in isothermal and exponential cooling approximations for peak temperatures in the range 600–700°C, this leads to a time scale for calcium-aluminum-rich inclusion (CAI) alteration in the range of decades to centuries

Measuring deviant sexual interest in Adolescents using the emotional Stroop task.

Adolescent sexual abusers are a heterogeneous group of offenders that often receive generic assessment and treatment services that are modeled on research findings from adult sex offender samples. The emotional Stroop task has been used to measure deviant sexual interest in adult samples. The purpose of the present study was to test whether the emotional Stroop task could also be used to assess deviant sexual interest in adolescent samples. Three groups of adolescents (a) sexual abusers (n = 24); (b) offending controls (n = 21); and (c) nonoffending controls (n = 21) completed two emotional Stroop tasks related to deviant sexual interest and tests of executive function. Adolescent sexual abusers were significantly slower to color-name some word stimuli than both adolescent offending controls and adolescent nonoffending controls. However, the task was unable to differentiate between the groups on most of the Stroop word categories. Very little research has been conducted with adolescent offender samples and the emotional Stroop task. Reaction time (RT) and Stroop bias outcome data for adolescent samples appear to be more unsystematic and weaker than has been observed in previous adult data. Based on potential difficulties with reading and development, the emotional Stroop task may not be a task suitable for measuring deviant sexual interest in adolescent samples

Event-Driven Network Programming

Software-defined networking (SDN) programs must simultaneously describe static forwarding behavior and dynamic updates in response to events. Event-driven updates are critical to get right, but difficult to implement correctly due to the high degree of concurrency in networks. Existing SDN platforms offer weak guarantees that can break application invariants, leading to problems such as dropped packets, degraded performance, security violations, etc. This paper introduces EVENT-DRIVEN CONSISTENT UPDATES that are guaranteed to preserve well-defined behaviors when transitioning between configurations in response to events. We propose NETWORK EVENT STRUCTURES (NESs) to model constraints on updates, such as which events can be enabled simultaneously and causal dependencies between events. We define an extension of the NetKAT language with mutable state, give semantics to stateful programs using NESs, and discuss provably-correct strategies for implementing NESs in SDNs. Finally, we evaluate our approach empirically, demonstrating that it gives well-defined consistency guarantees while avoiding expensive synchronization and packet buffering

Materials Older Than Ca-Al-Rich Inclusions

Concentrations of refractory lithophile elements (RLEs) in Type B1 Ca-Al-rich inclusions (CAIs) are dominated by submicron inclusions, which are potentially relict grains older than the host CAI. These objects are so common, albeit tiny, that it is often very difficult to find a “pure” melilite

The complete nucleotide sequence of the genome of Barley yellow dwarf virus-RMV reveals it to be a new Polerovirus distantly related to other yellow dwarf viruses

The yellow dwarf viruses (YDVs) of the Luteoviridae family represent the most widespread group of cereal viruses worldwide. They include the Barley yellow dwarf viruses (BYDVs) of genus Luteovirus, the Cereal yellow dwarf viruses (CYDVs) and Wheat yellow dwarf virus (WYDV) of genus Polerovirus. All of these viruses are obligately aphid transmitted and phloem-limited. The first described YDVs (initially all called BYDV) were classified by their most efficient vector. One of these viruses, BYDV-RMV, is transmitted most efficiently by the corn leaf aphid, Rhopalosiphum maidis. Here we report the complete 5612 nucleotide sequence of the genomic RNA of a Montana isolate of BYDV-RMV (isolate RMV MTFE87, Genbank accession no. KC921392). The sequence revealed that BYDV-RMV is a polerovirus, but it is quite distantly related to the CYDVs or WYDV, which are very closely related to each other. Nor is BYDV-RMV closely related to any other particular polerovirus. Depending on the gene that is compared, different poleroviruses (none of them a YDV) share the most sequence similarity to BYDV-RMV. Because of its distant relationship to other YDVs, and because it commonly infects maize via its vector, R. maidis, we propose that BYDV-RMV be renamed Maize yellow dwarf virus-RMV (MYDV-RMV)

The Stability of Zirconia-Saturated Perovskite and Conditions in the Early Solar System

Perovskite and tazheranite (cubic zirconia) are among the most refractory oxides in nebular vapors [1] and important repositories for several refractory elements whose concentrations can potentially be used to constrain the environments of formation. There are numerous studies on the phase relations and thermodynamic properties of zirconias containing Al, Ca, Mg, Sc, Ti, and the REE [e.g., 2-4], but meteoritic zirconia is rare [5]. Meteoritic perovskite is much more common [e.g., 5-9], but there are few constraints on thermodynamic properties of the relevant solid solutions. Here, we describe experiments to determine the partitioning of minor elements between perovskite and zirconia of variable Zr/Ti; the results will be used to constrain thermodynamic modeling for the solid solutions represented by meteoritic perovskite

Confidentiality and public protection: ethical dilemmas in qualitative research with adult male sex offenders

This paper considers the ethical tensions present when engaging in in-depth interviews with convicted sex offenders. Many of the issues described below are similar to those found in other sensitive areas of research. However, confidentiality and public protection are matters that require detailed consideration when the desire to know more about men who have committed serious and harmful offences is set against the possibility of a researcher not disclosing previously unknown sensitive information that relates to the risk of someone being harmed.</p

Survival of presolar silicon carbide grains during parent-body metamorphism: constraints on the composition of metamorphic fluids

Systematic variations in the abundances of presolar grains of Sic and diamond with petrologic type in unequilibrated ordinary chondrites (UOCs) [1,2] probably reflect differences in P-T conditions and/or fluid composition during parent-body metamorphism. It may, therefore, be possible to constrain physical conditions during the metamorphism by determining the conditions under which presolar grains are destroyed