Oxidized basalts on the surface of Venus: Compositional implications of measured spectral properties

Venera Lander reflectance data are compared with high temperature spectra of the same basaltic materials. The dark, flat unoxidized basalts are still inconsistent with the Venera data in the near-infrared. Basaltic material with a ferric component, however, would satisfy both the increase in reflectance beyond 0.7 microns as well as the dark, relatively colorless character in the visible. Therefore, it is concluded that besaltic surfaces of Venus represented by these measurements either contain minerals with uncommon characteristics, or, more likely, are relatively oxidized

Planetary Volcanism

The final report consists of 10 journal articles concerning Planetary Volcanism. The articles discuss the following topics: (1) lunar stratigraphy; (2) cryptomare thickness measurements; (3) spherical harmonic spectra; (4) late stage activity of volcanoes on Venus; (5) stresses and calderas on Mars; (6) magma reservoir failure; (7) lunar mare basalt volcanism; (8) impact and volcanic glasses in the 79001/2 Core; (9) geology of the lunar regional dark mantle deposits; and (10) factors controlling the depths and sizes of magma reservoirs in Martian volcanoes

Combatting electoral traces: the Dutch tempest discussion and beyond

In the Dutch e-voting debate, the crucial issue leading to the abandonment of all electronic voting machines was compromising radiation, or tempest. Other countries, however, do not seem to be bothered by this risk. In this paper, we use actor-network theory to analyse the socio-technical origins of the Dutch tempest issue in e-voting, and its consequences for e-voting beyond the Netherlands. We introduce the term electoral traces to denote any physical, digital or social evidence of a voter's choices in an election. From this perspective, we provide guidelines for risk analysis as well as an overview of countermeasures

Epidemiological evidence of cervical intraepithelial neoplasia without the presence of human papillomavirus.

The aim of this paper was to provide epidemiological evidence to support the notion that cervical intraepithelial neoplasia (CIN) without human papillomavirus (HPV) is a true entity. If a diagnosis of HPV-negative cervical neoplasia is erroneous, one would not expect there to be any differences in risk factors between HPV-positive and HPV-negative patients. Patients at a gynaecological outpatient clinic of a university hospital [a total of 265 consecutive women with dyskaryotic cervical smears who were subsequently diagnosed with CIN I (n=37), CIN II (n=48) or CIN III (n=180)] completed a structured questionnaire regarding smoking habits and sexual history. Analysis of an endocervical swab for Chlamydia trachomatis, analysis of a cervical scrape for HPV, and morphological examination of cervical biopsy specimens were also performed. HPV was found in 205 (77.4%) out of the 265 women. Univariate analysis showed that current age (P=0.02), current smoking behaviour (P=0.002) and the number of sexual partners (P=0.02) were significantly associated with the presence of HPV. Age at first sexual intercourse, a past history of venereal disease or genital warts, and current infection with Chlamydia trachomatis were not associated with the presence of HPV. Using multivariate logistic regression analysis, the number of sexual partners and current smoking behaviour showed an independent significant association with HPV. HPV-negative and HPV-positive CIN patients differ with respect to the risk factors for HPV. These findings suggest that HPV-negative CIN is a separate true entity

Inhaled Anesthetics Promote Albumin Dimerization through Reciprocal Exchange of Subdomains

Inhaled anesthetics affect protein-protein interaction, but the mechanisms underlying these effects are still poorly understood. We examined the impact of sevoflurane and isoflurane on the dimerization of human serum albumin (HSA), a protein with anesthetic binding sites that are well characterized. Intrinsic fluorescence emission was analyzed for spectral shifting and self-quenching, and control first derivatives (spectral responses to changes in HSA concentration) were compared against those obtained from samples treated with sevoflurane or isoflurane. Sevoflurane increased dimer-dependent self-quenching and both decreased oligomer-dependent spectral shifting, suggesting that inhaled anesthetics promoted HSA dimerization. Size exclusion chromatography and polarization data were consistent with these observations. The data support the proposed model of a reciprocal exchange of subdomains to form an HSA dimer. The open-ended exchange of subdomains, which we propose occuring in HSA oligomers, was inhibited by sevoflurane and isoflurane

Mineralogy of the Mafic Anomaly in the South Pole-Aitken Basin: Implications for excavation of the lunar mantle

Mineralogy of South Pole-Aitken Basin (SPA) (the largest confirmed impact basin on the Moon) is evaluated using five-color images from Clementine. Although olivine-rich material as well as basalts rich in clinopyroxene are readily identified elsewhere on the farside, the dominant rock type observed across the interior of SPA is of a very noritic composition. This mineralogy suggests that lower crust rather than the mantle is the dominant source of the mafic component at SPA. The lack of variation in observed noritic composition is probably due to basin formation processes, during which extensive melting and mixing of target materials are likely to occur

Learning within sustainable educational innovation:An analysis of teachers' perceptions and leadership practice

Innovative initiatives in education often have problems with their sustainability. The present study focuses on three educational innovations that have proved to be sustainable over time. We used a qualitative research approach to study and identify essential features of sustainable educational innovation. Two theoretical frameworks were used to guide the study: the integrated model for sustainable innovation (IMSI) and self-determination theory (SDT). Both frameworks take a different perspective upon learning; IMSI presents learning at the individual level, the team level and the organizational level to be the heart of sustainable innovation, and SDT presents how learning can be improved. The research question focused upon how the SDT concepts of autonomy, competence and relatedness were perceived within sustainable innovation, expressed by the IMSI framework, by teachers and school leaders. Based on our findings we demonstrate that the framework of IMSI and SDT can effectively be applied as a frame of analysis to identify essential features of sustainability in educational innovations and we discuss how concepts of SDT deepen the knowledge of sustainable educational innovation

Noise and dynamical pattern selection

In pattern forming systems such as Rayleigh-Benard convection or directional solidification, a large number of linearly stable, patterned steady states exist when the basic, simple steady state is unstable. Which of these steady states will be realized in a given experiment appears to depend on unobservable details of the system's initial conditions. We show, however, that weak, Gaussian white noise drives such a system toward a preferred wave number which depends only on the system parameters and is independent of initial conditions. We give a prescription for calculating this wave number, analytically near the onset of instability and numerically otherwise.Comment: 12 pages, REVTEX, no figures. Submitted to Phys. Rev. Let

Anion Distribution, Structural Distortion, and Symmetry-Driven Optical Band Gap Bowing in Mixed Halide Cs₂SnX₆ Vacancy Ordered Double Perovskites

Mixed anion compounds in the Fm-3m vacancy ordered perovskite structure were synthesised and characterised experimentally and computationally with a focus on compounds where A = Cs+. Pure anion Cs2SnX6 compounds were formed with X = Cl, Br and I using a room temperature solution phase method. Mixed anion compounds were formed as solid solutions of Cs2SnCl6 and Cs2SnBr6 and a second series from Cs2SnBr6 and Cs2SnI6. Single phase structures formed across the entirety of both composition series, with no evidence of long range anion ordering observed by diffraction. A distortion of the cubic A2BX6 structure was identified in which the spacing of the BX6 octahedra changes to accommodate the A site cation without reduction of overall symmetry. Optical band gap values varied with anion composition between 4.89 eV in Cs2SnCl6 to 1.35 eV in Cs2SnI6, but proved highly non-linear with changes in composition. In mixed halide compounds it was found that lower energy optical transitions appeared that were not present in the pure halide compounds, and this could be attributed to lowering of the local symmetry within the tin halide octahedra. The electronic structure was characterised by photoemission spectroscopy, and Raman spectroscopy revealed vibrational modes in the mixed halide compounds that could be assigned to particular mixed halide octahedra. This analysis was used to determine the distribution of octahedra types in mixed anion compounds, which was found to be consistent with a near-random distribution of halide anions throughout the structure, although some deviations from random halide distribution were noted in mixed iodide-bromide compounds, where the larger iodide anions preferentially adopted trans configurations