The importance of precipitation rate as an effective control on illite and kaolanite formation during diagenesis has been examined by measuring precipitation rates, from Al fluid concentration, in a Dickson fluid-sampling vessel at 160°-250° and 500 bars (50 MPa). These experiments are considered to be analogues of the precipitation of clays in sandstones from porewaters containing dissolved carboxylic acids, which have a transient stability and may influence aluminosilicate solubility. Precipitated illite had a lath-shaped morphology and its composition was consistent with authigenic illite in sandstones. Kaolinite formed tabular rather than vermicular shaped crystals. Kaolinite precipitation rate was two orders of magnitude faster than illite precipitation and was rate-limited by the decomposition of oxalate; kaolinite formation should be equilibrium-controlled at virtually all stages of burial. Extrapolation of illite precipitation rate to burial temperatures indicates that the first appearance of illite in a burial sequence may be kinetically controlled. A model of illite precipitation based on these experimental results has been used to predict the time required to precipitate illite during burial of a sandstone, taking into account temperature changes during burial. For northern North Sea examples, a predicted illitization threshold of -60°C occurring at 60–80 Ma corresponds to the observed initiation of authigenic illite precipitation. Times of around 2–5 Ma would be required to reach a 98% approach to equilibrium at this threshold. The main phase of illite precipitation in the northern North Sea basin is a later, hydrologically controlled event (30-50 Ma). Equilibrium would be approached in around 0.1 Ma during this phase, which is consistent with the narrow illite K/Ar age range (1-5 Ma) recorded for some sequences.

We discuss some causal estimands that are used to study racial discrimination in policing. A central challenge is that not all police–civilian encounters are recorded in administrative datasets and available to researchers. One possible solution is to consider the average causal effect of race conditional on the civilian already being detained by the police. We find that such an estimand can be quite different from the more familiar ones in causal inference and needs to be interpreted with caution. We propose using an estimand that is new for this context—the causal risk ratio, which has more transparent interpretation and requires weaker identification assumptions. We demonstrate this through a reanalysis of the NYPD Stop-and-Frisk dataset. Our reanalysis shows that the naive estimator that ignores the posttreatment selection in administrative records may severely underestimate the disparity in police violence between minorities and whites in these and similar data.

We describe the glacial geomorphology and initial geochronology of two ice-free valley systems within the Neptune Range of the Pensacola Mountains, Antarctica. These valleys are characterized by landforms associated with formerly more expanded ice sheet(s) that were at least 200 m thicker than at present. The most conspicuous features are areas of supraglacial debris, discrete debris accumulations separated from modern-day ice and curvilinear ridges and mounds. The landsystem bears similarities to debris-rich cold-based glacial landsystems described elsewhere in Antarctica and the Arctic where buried ice is prevalent. Geochronological data demonstrate multiple phases of ice expansion. The oldest, occurring > 3 Ma, overtopped much of the landscape. Subsequent, less expansive advances into the valleys occurred > 2 Ma and > ~1 Ma. An expansion of some local glaciers occurred < 250 ka. This sequence of glacial stages is similar to that described from the northernmost massif of the Pensacola Mountains (Dufek Massif), suggesting that it represents a regional signal of ice-sheet evolution over the Plio-Pleistocene. The geomorphological record and its evolution over millions of years makes the Neptune Range valleys an area worthy of future research and we highlight potential avenues for this.

TwinsUK is the largest cohort of community-dwelling adult twins in the UK. The registry comprises over 14,000 volunteer twins (14,838 including mixed, single and triplets); it is predominantly female (82%) and middle-aged (mean age 59). In addition, over 1800 parents and siblings of twins are registered volunteers. During the last 27 years, TwinsUK has collected numerous questionnaire responses, physical/cognitive measures and biological measures on over 8500 subjects. Data were collected alongside four comprehensive phenotyping clinical visits to the Department of Twin Research and Genetic Epidemiology, King’s College London. Such collection methods have resulted in very detailed longitudinal clinical, biochemical, behavioral, dietary and socioeconomic cohort characterization; it provides a multidisciplinary platform for the study of complex disease during the adult life course, including the process of healthy aging. The major strength of TwinsUK is the availability of several ‘omic’ technologies for a range of sample types from participants, which includes genomewide scans of single-nucleotide variants, next-generation sequencing, metabolomic profiles, microbiomics, exome sequencing, epigenetic markers, gene expression arrays, RNA sequencing and telomere length measures. TwinsUK facilitates and actively encourages sharing the ‘TwinsUK’ resource with the scientific community — interested researchers may request data via the TwinsUK website (http://twinsuk.ac.uk/resources-for-researchers/access-our-data/) for their own use or future collaboration with the study team. In addition, further cohort data collection is planned via the Wellcome Open Research gateway (https://wellcomeopenresearch.org/gateways). The current article presents an up-to-date report on the application of technological advances, new study procedures in the cohort and future direction of TwinsUK.

The smectite-to-illite reaction (illitization) was examined in a dilute suspension of Wyoming bentonite in the presence of oxalate and acetate. Experiments were performed using fluidsampling apparatus at 200°C, 50 MPa, in which progressive changes in both clay mineralogy and fluid composition were monitored. The presence of K-oxalate and K-acetate under neutral-alkaline conditions produced significant reaction of smectite to either R1 or R2 ordered illite-smectite with 60–70% illite layers. Experiments at the same temperature with KCl, or oxalic acid plus KCl, produced no reaction. Fluid chemistry showed that K-oxalate and K-acetate resulted in the establishment of aK+/aH+ conditions within the muscovite stability field, favouring the formation of illite. The extent of dissolution and precipitation indicated by fluid data is insufficient to account for the amount of illitization evident in the mineralogy. This implies that a localized dissolution-precipitation process occurs, perhaps on the scale of a single clay particle. These experiments highlight the importance of pH as a control over illitization and show that organic anions can buffer fluid composition into the optimum aK+/aH+ condition for illitization. These findings are highly significant for the smectite-to-illite reaction occurring in organic bearing sediments where organic acid anions are generated during kerogen maturation.

Clay mineral abundances and illite-smectite (I/S) compositions have been determined by X-ray diffraction (XRD) in shales of Permo-Triassic to Quaternary age from seven wells in the Viking Graben and Moray Firth. Chemical analyses of size fractions provide evidence that diagenetic illitization of smectite has occurred during burial by uptake of Al and K, and release of Si. K-feldspar was probably the main source of K for illitization. The depth at which random I/S disappears occurs at similar temperatures (mean 93°C) in each well for which reliable measurements are available. Vitrinite reflectance measurements at this depth are also similar (mean 0·64% R0) and correspond to early oil generation. I/S diagenetic levels may have been imprinted by a Tertiary heating event.

Experiments to explore the dissolution behaviour of Pb-rich orthoclase (1% PbO) and quartz have been carried out in the presence of pH buffered and unbuffered potassium acetate and lithium acetate solutions at 150°C and 50 MPa (500 bars). In pH-unbuffered potassium acetate solutions Pb and Na solubilities (and pH) increase with increasing fluid acetate content, reflecting increased bulk dissolution of the feldspar; silica solubility decreases despite an increase in measured pH from 7.5 to 8.9. Similarly, in experiments at pH 6 using a potassium acetate pH buffer, quartz solubility decreases with increasing acetate content. The use of lithium acetate pH buffers (pH 6 at 25°C) in experiments with orthoclase plus quartz results in the precipitation of the lithium chlorite cookeite, complicating interpretation of the fluid chemistry. It is also apparent that in the presence of orthoclase plus quartz (but not albite alone) acetate decarboxylation takes place at much higher rates than expected for the experimental configuration used. The observed effects are unlikely to be due to the presence of acetate alone; the influence of species produced by acetate decay (especially carbonate) must also be considered. This study provides little support for models which call upon acetate to enhance the solubility of aluminosilicate minerals, and suggests that acetate decarboxylation in nature may limit its involvement in dissolution processes. It emphasises the potential of feldspars as sources of elements for mineralisation, such as Pb.

In this prospective study of upper middle class youth, we document frequency of alcohol and drug use, as well as diagnoses of abuse and dependence, during early adulthood. Two cohorts were assessed as high school seniors and then annually across 4 college years (New England Study of Suburban Youth younger cohort [NESSY-Y]), and across ages 23–27 (NESSY older cohort [NESSY-O]; ns = 152 and 183 at final assessments, respectively). Across gender and annual assessments, results showed substantial elevations, relative to norms, for frequency of drunkenness and using marijuana, stimulants, and cocaine. Of more concern were psychiatric diagnoses of alcohol/drug dependence: among women and men, respectively, lifetime rates ranged between 19%–24% and 23%–40% among NESSY-Os at age 26; and 11%–16% and 19%–27% among NESSY-Ys at 22. Relative to norms, these rates among NESSY-O women and men were three and two times as high, respectively, and among NESSY-Y, close to one among women but twice as high among men. Findings also showed the protective power of parents’ containment (anticipated stringency of repercussions for substance use) at age 18; this was inversely associated with frequency of drunkenness and marijuana and stimulant use in adulthood. Results emphasize the need to take seriously the elevated rates of substance documented among adolescents in affluent American school communities.

The Sahel in West Africa is a major wintering area for many western Palearctic migrants. The breeding populations of many of these have declined over the past 50 years. However, there have been few intensive field studies on migrant ecology in the Sahel and these were generally within a very restricted area. Consequently our knowledge of the distribution of species within this extensive area and the habitat associations of these species is limited. Understanding these habitat associations is essential for the effective conservation management of populations. We brought together a group of experts and consulted a wider group by email to assess the main Sahelian habitat types used by 68 African-Eurasian migrant bird species. Those species that showed strongest declines during 1970–1990 were associated with more open habitats than those newly declining during 1990–2000, when declining species were associated with habitats with more shrubs and trees. Populations of species that winter in the Sahel are generally stable or increasing now as rainfall has increased and is now near the long-term average for the Sahel. Those which use the Sahel only as a staging area are, in many cases, in rapid decline at present.

Background: Whether perceived changes in memory parallel changes in brain pathology is uncertain. Positron emission tomography (PET) scans using 2-(1-{6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile (FDDNP) can measure levels of amyloid plaques and tau neurofibrillary tangles in vivo. Here we investigate whether degree of self-reported memory impairment is associated with FDDNP-PET binding levels in persons without dementia.

Methods: Fifty-seven middle-aged and older adults without dementia (mean age ±standard deviation = 66.3 ± 10.6 years), including 25 with normal aging and 32 with mild cognitive impairment (MCI), were assessed. The outcome measures were the four factor scores of the Memory Functioning Questionnaire (MFQ) (frequency of forgetting, seriousness of forgetting, retrospective functioning, and mnemonics use) and FDDNP-PET binding levels in medial temporal, lateral temporal, posterior cingulate, parietal, frontal, and global (overall average) regions of interest.

Results: After controlling for age, higher reported frequency of forgetting was associated with greater medial temporal (r = −0.29, p = 0.05), parietal (r = −0.30, p = 0.03), frontal (r = −0.35, p = 0.01), and global FDDNP-PET binding levels (r = −0.33, p = 0.02). The remaining MFQ factor scores were not significantly associated with FDDNP-PET binding levels, and no significant differences were found between normal aging and MCI subjects. Item analysis of the frequency of forgetting factor revealed five questions that yielded similar results as the full 32-question scale (r = −0.52, p = 0.0002).

Conclusions: These findings suggest that some forms of memory self-awareness, in particular the reported frequency of forgetting, may reflect the extent of cerebral amyloid and tau brain pathology.

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Bulk silicon-germanium (SiGe) alloys and two SiGe thick films (4 and 5 μm) on Si wafers were tested with the electron probe microanalyzer (EPMA) using wavelength dispersive spectrometers (WDS) for heterogeneity and composition for use as reference materials needed by the microelectronics industry. One alloy with a nominal composition of Si0.86Ge0.14 and the two thick films with nominal compositions of Si0.90Ge0.10 and Si0.75Ge0.25 on Si, evaluated for micro- and macroheterogeneity, will make good microanalysis reference materials with an overall expanded heterogeneity uncertainty of 1.1% relative or less for Ge. The bulk Ge composition in the Si0.86Ge0.14 alloy was determined to be 30.228% mass fraction Ge with an expanded uncertainty of the mean of 0.195% mass fraction. The thick films were quantified with WDS-EPMA using both the Si0.86Ge0.14 alloy and element wafers as reference materials. The Ge concentration was determined to be 22.80% mass fraction with an expanded uncertainty of the mean of 0.12% mass fraction for the Si0.90Ge0.10 wafer and 43.66% mass fraction for the Si0.75Ge0.25 wafer with an expanded uncertainty of the mean of 0.25% mass fraction. The two thick SiGe films will be issued as National Institute of Standards and Technology Reference Materials (RM 8905).

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Ten species of marine strombidiid ciliates were identified after protargol staining plankton samples. The taxonomic redescriptions include a diagnosis for Tontonia gracillima Faure-Fremiet, 1924, Strombidium wulffi (Wulff, 1919) Kahl, 1932, Strombidium acutum Leegaard, 1915, Strombidium constrictum (Meunier, 1910) Wulff, 1919, Strombidium compressum (Leegaard, 1915) Kahl, 1932, and Strombidium sulcatum Claparede & Lachmann, 1858. Four new species, Strombidium dalum n.sp., Strombidium epidemum n.sp., Strombidium rhynchum n.sp., and Strombidium tressum n.sp., are defined based primarily on the characteristics of the anterior oral polykinetids, numbers of oral polykinetids, and presence of anterior protuberance.

Our experience with shape memory polymers (SMP) began with a project to develop an embolic coil release actuator in 1996. This was the first known SMP device to enter human trials. Recent progress with the SMP devices include multiple device applications (stroke treatments, stents, other interventional devices), functional animal studies, synthesis and characterization of new SMP materials, in vivo and in vitro biocompatibility studies and device-tissue interactions for the laser, resistive, or magnetic-field activated actuators. We describe several of our applied SMP devices.