The trace element selenium is known to protect against oxidative damage which is known to contribute to cognitive impairment with ageing (1,2). The aim of this study was to explore the association between selenium status (serum selenium and selenoprotein P (SELENOP)) and global cognitive performance at baseline and after 5 years in 85-year-olds living in the Northeast of England.

Serum selenium and SELENOP concentrations were measured at baseline by total reflection X-ray fluorescence (TXRF) and enzyme-linked immunosorbent assay (ELISA), respectively, in 757 participants from the Newcastle 85+ study. Global cognitive performance was assessed using the Standardized Mini-Mental State Examination (SMMSE) where scores ≤25 out of 30 indicated cognitive impairment. Logistic regressions explored the associations between selenium status and global cognition at baseline. Linear mixed models explored associations between selenium status and global cognition prospectively after 5 years. Covariates included sex, body mass index, physical activity, high sensitivity C-reactive protein, alcohol intake, self-rated health, medications and smoking status.

At baseline, in fully adjusted models, there was no increase in odds of cognitive impairment with serum selenium (OR 1.004, 95% CI 0.993-1.015, p = 0.512) or between SELENOP (OR 1.006, 95% CI 0.881-1.149, p = 0.930). Likewise, over 5 years, in fully adjusted models there was no association between serum selenium and cognitive impairment (β 7.20E-4 ± 5.57E-4, p = 0.197), or between SELENOP and cognitive impairment (β 3.50E-3 ± 6.85E-3, p = 0.610).

In this UK cohort of very old adults, serum selenium or SELENOP was not associated with cognitive impairment at baseline and 5 years. This was an unexpected finding despite SELENOP’s key role in the brain and the observed associations in other studies. Further research is needed to explore the effect of selenium on global cognition in very old adults.

There is a dearth of data on Se status in very old adults. The aims of this study were to assess Se status and its determinants in 85-year-olds living in the Northeast of England by measuring serum Se and selenoprotein P (SELENOP) concentrations and glutathione peroxidase 3 (GPx3) activity. A secondary aim was to examine the interrelationships between each of the biomarkers. In total, 757 participants (463 women, 293 men) from the Newcastle 85+ Study were included. Biomarker concentrations were compared with selected cut-offs (serum Se: suboptimal 70 µg/l and deficient 45 µg/l; SELENOP: suboptimal 4·5 mg/l and deficient 2·6 mg/l). Determinants were assessed using linear regressions, and interrelationships were assessed using restricted cubic splines. Median (inter-quartile range) concentrations of serum Se, SELENOP and of GPx3 activity were 53·6 (23·6) µg/l, 2·9 (1·9) mg/l and 142·1 (50·7) U/l, respectively. Eighty-two percentage and 83 % of participants had suboptimal serum Se (< 70 µg/l) and SELENOP (< 4·5 mg/l), and 31 % and 40 % of participants had deficient serum Se (< 45 µg/l) and SELENOP (< 2·6 mg/l), respectively. Protein intake was a significant determinant of Se status. Additional determinants of serum Se were sex, waist:hip ratio, self-rated health and disease, while sex, BMI and physical activity were determinants of GPx3 activity. There was a linear association between serum Se and SELENOP, and nonlinear associations between serum Se and GPx3 activity and between SELENOP and GPx3 activity. These findings indicate that most participants had suboptimal Se status to saturate circulating SELENOP.

Laboratory animals need to be monitored to check the status of their health and welfare. Routine checks of laboratory fish are limited to visual observations of physical appearance and behaviour, but for species held in opaque-walled tanks, such checks are compromised by restricted views, poor visibility and provoked behaviour. Here, we report our experience of using in-tank underwater cameras to monitor laboratory populations of salmoniforme, perciforme and cypriniforme fish. A range of cameras and lenses were investigated and trialled. A standard VGA resolution analogue camera with a one-third-inch chip and 3.6-mm lens was selected based on size, picture quality, the proportion of tank in view and cost. A shell for the camera and mounting system were designed to minimise size and cleaning and enable flexible positioning within tanks. Cameras were connected via digital encoders to a server, making video available to the general computer network. Data collected from recordings of rainbow trout (Oncorhynchus mykiss) confirmed provoked behaviour, ie a change in distribution and increase in activity in response to direct viewing and feeding. The networked cameras therefore enable remote viewing of undisturbed behaviour in real time, providing clear, lateral views unaffected by water surface effects, and facilitate increased frequency of checking. Case studies illustrate how camera monitoring can aid detection of abnormalities in behaviour (eg lack of feeding, posture, swimming) and appearance (eg clinical signs, such as lesions), enabling earlier interventions. Furthermore, recordings provide a resource for reference and retrospective analysis, and evidence to support severity classification and identify humane end-points.

The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.

The direct carbonate procedure for accelerator mass spectrometry radiocarbon (AMS 14C) dating of submilligram samples of biogenic carbonate without graphitization is becoming widely used in a variety of studies. We compare the results of 153 paired direct carbonate and standard graphite 14C determinations on single specimens of an assortment of biogenic carbonates. A reduced major axis regression shows a strong relationship between direct carbonate and graphite percent Modern Carbon (pMC) values (m = 0.996; 95% CI [0.991–1.001]). An analysis of differences and a 95% confidence interval on pMC values reveals that there is no significant difference between direct carbonate and graphite pMC values for 76% of analyzed specimens, although variation in direct carbonate pMC is underestimated. The difference between the two methods is typically within 2 pMC, with 61% of direct carbonate pMC measurements being higher than their paired graphite counterpart. Of the 36 specimens that did yield significant differences, all but three missed the 95% significance threshold by 1.2 pMC or less. These results show that direct carbonate 14C dating of biogenic carbonates is a cost-effective and efficient complement to standard graphite 14C dating.

The triazines are one of the most widely used herbicide classes ever developed and are critical for managing weed populations that have developed herbicide resistance. These herbicides are traditionally valued for their residual weed control in more than 50 crops. Scientific literature suggests that atrazine, and perhaps other s-triazines, may no longer remain persistent in soils due to enhanced microbial degradation. Experiments examined the rate of degradation of atrazine and two other triazine herbicides, simazine and metribuzin, in both atrazine-adapted and non-history Corn Belt soils, with similar soils being used from each state as a comparison of potential triazine degradation. In three soils with no history of atrazine use, the t1/2 of atrazine was at least four times greater than in three soils with a history of atrazine use. Simazine degradation in the same three sets of soils was 2.4 to 15 times more rapid in history soils than non-history soils. Metribuzin in history soils degraded at 0.6, 0.9, and 1.9 times the rate seen in the same three non-history soils. These results indicate enhanced degradation of the symmetrical triazine simazine, but not of the asymmetrical triazine metribuzin.

The structure and elastic properties of MgSiO3, a major mantle-forming phase, have been simulated using computer models which predict the minimum energy structure by using interatomic pair potentials to describe the net forces acting between the atoms. Four such interatomic potentials were developed in this study, and are compared with potential N1 of Miyamoto and Takeda (1984). The most successful potential (W3) was derived by fitting the short range potential parameters to both the experimentally obtained structural and elastic properties of MgSiO3 perovskite. The relative stabilities of some of the possible perovskite polymorphs, the orthorhombic, cubic, and tetragonal phases and hexagonal polytypes, were evaluated at 0 K and between 1 bar and 2 Mbar. The orthorhombic phase is found to be stable at all but the highest pressures, where the cubic phase may be stable. The temperature of the ortho-rhombic to cubic transition may decrease with increasing pressure. The energy of a stacking fault on (110) in the cubic phase was estimated using the ANNNI model and found to be about 1.95 J m−2 using potential W3. The distance of separation of partial dislocations of this type is predicted to increase with increasing pressure from 8.4 Å at 1 bar to 9.2 Å at 1 Mbar.

History suggests that social movements for change are often met with powerful counter-movements. Relying upon movement counter-movement dynamics, this paper examines whether or not contemporary reactionary conservatism—in this case Donald Trump's candidacy in 2016, offers an opportunity for African-American mobilization. Today, the reactionary right presents a threat to racial progress and the black community as it has grown from direct opposition to the election of President Obama, immigration reform, and gay and lesbian rights. With conditions ripe for a movement in response to the right, we examine the mobilizing effect on African-Americans of the threatening political context symbolized by Donald Trump. If African-Americans are to retain political relevance beyond the Obama era, then black turnout will need to reach rates similar to the historic 2008 election. Using the 2016 Black Voter Project (BVP) Pilot Study, we explore African-American political engagement in the 2016 election, a time void of President Obama as a mobilizing figure. We find that African-Americans who hold strong negative opinions of Trump in 2016 voted at rates similar to the historical turnout of 2008, offering a possible strategy to mobilize blacks beyond Obama's presidency. Moreover, the threat that Trump represents significantly drives blacks to engage in politics beyond voting even after accounting for alternative explanations. In the end, Trump and the reactionary movement behind him offers a powerful mobilizing force for an African-American population that can no longer look toward the top of the Presidential ticket for inspiration.

We present simultaneous two-dimensional velocity and scalar measurements on a central vertical plane in an axisymmetric pure turbulent plume. We use an edge-detection algorithm to determine the edge of the plume, and compare the data obtained in both a fixed Eulerian frame and a frame relative to local coordinates defined in terms of the instantaneous plume edge. In an Eulerian frame we observe that the time-averaged distributions of vertical and horizontal velocity are self-similar, the vertical velocity being well represented by a Gaussian distribution. We condition these measurements on whether fluid is inside or outside of the plume, and whether fluid inside is mixed plume fluid or engulfed ambient fluid. We find that, on average, 5 % of the total vertical volume transport occurs outside the plume and this figure rises to nearly 14 % at heights between large-scale coherent structures. We show that the fluxes of engulfed fluid within the plume envelope are slightly larger than the vertical transport outside the plume – indicating that ambient fluid is engulfed into the plume envelope before being nibbled across the turbulent/non-turbulent interface (TNTI) and then ultimately irreversibly mixed. Our new measurements in the plume coordinate (following the meandering fluctuating plume) show the flow within the plume and in the nearby ambient fluid is strongly influenced by whether an eddy is present locally within the plume, or absent. When an eddy is present and the plume is wide, the vertical velocities near the plume edge are small and hence all vertical transport is inside the plume. In regions where the plume is narrow and there is no eddy, large vertical velocities and hence transport are observed outside the plume suggesting that pressure forces associated with the eddies accelerate ambient fluid which is then engulfed into the plume. Finally, we show that observing significant vertical velocities beyond the scalar edge of the plume does not suggest that the characteristic width of the velocity distribution is greater than that of the scalar field; on the contrary, we show our observations to be consistent with a buoyancy distribution that is up to 20 % wider than that of the velocity. Measurements in the plume coordinates show that the mixing of momentum across the plume results in a distribution for which the differential entropy is close to maximal and the mixing of momentum is uninhibited (i.e. not bounded) by the TNTI of the plume. Furthermore, our measurements suggest that the scalar mixing across the plume may also result in a distribution for which the differential entropy is close to maximal but, in contrast to the momentum, the scalar mixing is strictly bounded by the plume edge.

Avian diet selection is hypothesized to be sensitive to seasonal changes in breeding status, but few tests exist for frugivorous tropical birds. Frugivorous birds provide an interesting test case because fruits are relatively deficient in minerals critical for reproduction. Here, we quantify annual patterns of fruit availability and diet for two frugivorous hornbill (Bucerotidae) species over a 5.5-y period to test for patterns of diet selection. Data from the lowland tropical rain forest of the Dja Reserve, Cameroon, are used to generate two nutritional indices. One index estimates the nutrient concentration of the diet chosen by Ceratogymna atrata and Bycanistes albotibialis on a monthly basis using 3165 feeding observations combined with fruit pulp sample data. The second index is an estimate of nutrient concentration of a non-selective or neutral diet across the study area based on tree fruiting phenology, vegetation survey and fruit-pulp sample data. Fifty-nine fruit pulp samples representing 40 species were analysed for 16 nutrient categories to contribute to both indices. Pulp samples accounted for approximately 75% of the observed diets. The results support expected patterns of nutrient selection. The two hornbill species selected a diet rich in calcium during the early breeding season (significantly so for B. albotibialis in July and August). Through the brooding and fledging periods, they switched from a calcium-rich diet to one rich in iron and caloric content as well as supplemental protein in the form of invertebrates. Calcium, the calcium to phosphorus ratio and fat concentration were the strongest predictors of breeding success (significant for calcium and Ca:P for B. albotibialis in June). We conclude that hornbills actively select fruit based on nutritional concentration and mineral concentration and that the indices developed here are useful for assessing frugivore diet over time.