Phage display selected magnetite interacting Adhirons for shape controlled nanoparticle synthesis

Adhirons are robust, well expressing, peptide display scaffold proteins, developed as an effective alternative to traditional antibody binding proteins for highly specific molecular recognition applications. This paper reports for the first time the use of these versatile proteins for material binding, and as tools for controlling material synthesis on the nanoscale. A phage library of Adhirons, each displaying two variable binding loops, was screened to identify specific proteins able to interact with [100] faces of cubic magnetite nanoparticles. The selected variable regions display a strong preference for basic residues such as lysine. Molecular dynamics simulations of amino acid adsorption onto a [100] magnetite surface provides a rationale for these interactions, with the lowest adsorption energy observed with lysine. These proteins direct the shape of the forming nanoparticles towards a cubic morphology in room temperature magnetite precipitation reactions, in stark contrast to the high temperature, harsh reaction conditions currently used to produce cubic nanoparticles. These effects demonstrate the utility of the selected Adhirons as novel magnetite mineralization control agents using ambient aqueous conditions. The approach we outline with artificial protein scaffolds has the potential to develop into a toolkit of novel additives for wider nanomaterial fabrication

Patterns of substance use across the first year of college and associated risk factors

Starting college is a major life transition. This study aims to characterize patterns of substance use across a variety of substances across the first year of college and identify associated factors. We used data from the first cohort (N = 2056, 1240 females) of the “Spit for Science” sample, a study of incoming freshmen at a large urban university. Latent transition analysis was applied to alcohol, tobacco, cannabis, and other illicit drug uses measured at the beginning of the fall semester and midway through the spring semester. Covariates across multiple domains – including personality, drinking motivations and expectancy, high school delinquency, peer deviance, stressful events, and symptoms of depression and anxiety – were included to predict the patterns of substance use and transitions between patterns across the first year. At both the fall and spring semesters, we identified three subgroups of participants with patterns of substance use characterized as: (1) use of all four substances; (2) alcohol, tobacco, and cannabis use; and (3) overall low substance use. Patterns of substance use were highly stable across the first year of college: most students maintained their class membership from fall to spring, with just 7% of participants in the initial low substance users transitioning to spring alcohol, tobacco, and cannabis users. Most of the included covariates were predictive of the initial pattern of use, but covariates related to experiences across the first year of college were more predictive of the transition from the low to alcohol, tobacco, and cannabis user groups. Our results suggest that while there is an overall increase in alcohol use across all students, college students largely maintain their patterns of substance use across the first year. Risk factors experienced during the first year may be effective targets for preventing increases in substance use

Molecular Genetic Influences on Normative and Problematic Alcohol Use in a Population-Based Sample of College Students

Background: Genetic factors impact alcohol use behaviors and these factors may become increasingly evident during emerging adulthood. Examination of the effects of individual variants as well as aggregate genetic variation can clarify mechanisms underlying risk. Methods: We conducted genome-wide association studies (GWAS) in an ethnically diverse sample of college students for three quantitative outcomes including typical monthly alcohol consumption, alcohol problems, and maximum number of drinks in 24 h. Heritability based on common genetic variants (h2SNP) was assessed. We also evaluated whether risk variants in aggregate were associated with alcohol use outcomes in an independent sample of young adults. Results: Two genome-wide significant markers were observed: rs11201929 in GRID1 for maximum drinks in 24 h, with supportive evidence across all ancestry groups; and rs73317305 in SAMD12 (alcohol problems), tested only in the African ancestry group. The h2SNP estimate was 0.19 (SE = 0.11) for consumption, and was non-significant for other outcomes. Genome-wide polygenic scores were significantly associated with alcohol outcomes in an independent sample. Conclusions: These results robustly identify genetic risk for alcohol use outcomes at the variant level and in aggregate. We confirm prior evidence that genetic variation in GRID1impacts alcohol use, and identify novel loci of interest for multiple alcohol outcomes in emerging adults. These findings indicate that genetic variation influencing normative and problematic alcohol use is, to some extent, convergent across ancestry groups. Studying college populations represents a promising avenue by which to obtain large, diverse samples for gene identification

'It's a film' : medium specificity as textual gesture in Red road and The unloved

British cinema has long been intertwined with television. The buzzwords of the transition to digital media, 'convergence' and 'multi-platform delivery', have particular histories in the British context which can be grasped only through an understanding of the cultural, historical and institutional peculiarities of the British film and television industries. Central to this understanding must be two comparisons: first, the relative stability of television in the duopoly period (at its core, the licence-funded BBC) in contrast to the repeated boom and bust of the many different financial/industrial combinations which have comprised the film industry; and second, the cultural and historical connotations of 'film' and 'television'. All readers of this journal will be familiar – possibly over-familiar – with the notion that 'British cinema is alive and well and living on television'. At the end of the first decade of the twenty-first century, when 'the end of medium specificity' is much trumpeted, it might be useful to return to the historical imbrication of British film and television, to explore both the possibility that medium specificity may be more nationally specific than much contemporary theorisation suggests, and to consider some of the relationships between film and television manifest at a textual level in two recent films, Red Road (2006) and The Unloved (2009)

Probing the extragalactic fast transient sky at minute timescales with DECam

Searches for optical transients are usually performed with a cadence of days to weeks, optimised for supernova discovery. The optical fast transient sky is still largely unexplored, with only a few surveys to date having placed meaningful constraints on the detection of extragalactic transients evolving at sub-hour timescales. Here, we present the results of deep searches for dim, minute-timescale extragalactic fast transients using the Dark Energy Camera, a core facility of our all-wavelength and all-messenger Deeper, Wider, Faster programme. We used continuous 20s exposures to systematically probe timescales down to 1.17 minutes at magnitude limits $g > 23$ (AB), detecting hundreds of transient and variable sources. Nine candidates passed our strict criteria on duration and non-stellarity, all of which could be classified as flare stars based on deep multi-band imaging. Searches for fast radio burst and gamma-ray counterparts during simultaneous multi-facility observations yielded no counterparts to the optical transients. Also, no long-term variability was detected with pre-imaging and follow-up observations using the SkyMapper optical telescope. We place upper limits for minute-timescale fast optical transient rates for a range of depths and timescales. Finally, we demonstrate that optical $g$-band light curve behaviour alone cannot discriminate between confirmed extragalactic fast transients such as prompt GRB flashes and Galactic stellar flares.Comment: Published in MNRA

Subdividing the savanna: the ecology of change in northern Tanzania

East African savannas are persistent socio-ecological systems undergoing unprecedented change. This dissertation focuses on the emerging agro-pastoral system of Maasai herders in the savanna lands adjacent to Tanzania’s Tarangire National Park. As pastoralists adopt cultivation, the relationship between humans and the land is changed. The new dynamics threaten the resilience of savanna systems. I examine three aspects of the human ecology of Maasai subsistence: changes in territory and political ecology, changes to the local common property system resulting from territorial compression, and how Maasai are responding to the production constraints of cultivation. I employed ethnography, social surveys, soil surveys and livestock demography to take a political ecology approach to investigating human-environment relations. Maasai territory is being fragmented by forces from within and without Maasai society. Poverty is increasing, due to market integration, high cattle mortality and population growth. Despite this, the adoption of cultivation cannot be explained by poverty alone. Poverty interacts with land tenure insecurity and with environmental stochasticity to create conditions conducive to the adoption of cultivation. Subdivision fragments the pastures which support pastoralism, reducing mobility and flexibility critical to dryland ecosystems. A village zoning plan has led to the emergence of a new common property regime that appears sufficient for current grazing and cultivation needs yet the historical pattern of land allocation means some villagers have greater access to protected pastures and water than others. Rich soils from abandoned kraals are also unequally distributed across the landscape. Pastoralists must negotiate limited cultivation experience, wildlife raids and labor shortages to integrate pastoral and agricultural production. Several trends suggest negative repercussions for future resilience of the socioecological system. Unequal resource distribution among land allocations, the history of interactions between stakeholder groups, and land use patterns that inadvertently concentrate resources among a few households are decreasing the flexibility demanded by semi-arid systems. To reduce the negative effects of cultivation, efforts should focus on improving yields on small plots, supporting livestock husbandry and integrating local residents and wildlife interests to build a resilient future

The role of proximate factors in shaping individual cognitive variation of great tits

Cognition is defined as the mechanisms that allow animals process, store and act on information. These mechanisms mediate behaviour and how animals interact with their environment. Yet not all individuals behave the same. While much of this variation may be attributed to differences in cognitive abilities among individuals, our understanding of why individuals vary in cognitive performance is limited. Examining the factors that drive individual variation in cognition is fundamental for understanding its adaptive significance, particularly when factors that determine how well an individual performs on a task may or may not be heritable. The aim of my thesis was to investigate how a range of distinct and understudied proximate factors shape individual variation in cognitive performance in great tits (Parus major) across different problem-solving and cognitive tasks. Using a multi-access problem-solving device to test sequential innovative problem-solving performance, I discovered that food-related motivation drives innovativeness and likelihood of solving, while previous experience drives accuracy and that individuals show repeatable differences in their accuracy and ability to solve. Between individual differences in problem solving performance were explained entirely by accuracy, motivation, and positive feedback loop caused by previous experience. Food is fundamental for survival and reproduction and food quality impacts cognition and behaviour. In my third chapter I found that diet correlated with problem-solving success, while personality correlated with the proportion of arachidonic acid, an ω-6 polyunsaturated fatty acid that is crucial for normal development and functioning of the brain. Great tits experience varying levels of predation risk as they forage in complex and fluctuating environments, but little is known about the effect of predation risk on learning and cognition in the context of foraging. In Chapter 4 I show that under high predation, birds demonstrated greater behavioural flexibility compared to those under low predation risk and displayed worse spatial memory for their reward location than those under medium or low predation risk. In Chapter 5 I take the spatio-temporal learning paradigm into the wild, and explore the effects of species, age and distance between feeders on discrimination and temporal learning. I show for the first time in the wild that both great tits and blue tits are capable of temporal and reversal temporal learning, but performance in any of these metrics were not correlated among individuals. Shorter distances between feeders resulted in faster discrimination learning performance, but had no effect on temporal learning. My thesis demonstrates how a variety of underexplored proximate factors explain individual variation in cognitive performance, emphasising the challenges faced when measuring cognition generally but especially in the wild

Investigating the horizontal transmissibility of bacterial metaldehyde and metazachlor-degrading genes

The molluscicide metaldehyde and the herbicide metazachlor have been detected in surface waters previously, posing risks to drinking water quality and the health of humans and wildlife. Soil-derived bacterial strains can degrade metaldehyde, a trait which was acquired by inferred horizontal gene transfer. The metaldehyde-degrading genes and plasmids responsible could be further disseminated to other bacterial strains by horizontal gene transfer. Novel pathways for the metaldehyde biodegradation process were also said to exist. In comparison, much less was known about the microbial biodegradation of metazachlor; however, it was predicted to occur in soils facilitated by bacterial glutathione conjugation by glutathione transferases. In vitro and soil microcosm-based facilitated horizontal gene transfer, selective enrichment, whole genome sequencing and bioinformatics approaches were employed to investigate the hypothesis that horizontal gene transfer processes could be harnessed experimentally to identify novel metaldehyde and metazachlor-degrading organisms, genes and metabolic pathways, and to demonstrate the horizontal transmissibility of metaldehyde and metazachlor-degrading genes. Two novel metaldehyde-degrading Acinetobacter calcoaceticus strains, 5.1 and 6.6, were isolated from allotment soils inoculated with the non-degrading bacterial strain Acinetobacter calcoaceticus RUH 2202. Two candidate metaldehyde-degrading genes, 15 and 2947, were identified in both strains. Additionally, three novel metazachlor-degrading Pseudomonas strains, 4.2.2, 4.5.2 and 6.4.2, were isolated from agricultural soils. Glutathione transferase enzymes, gstB_1, gstB_2, yibF, 4164, 3838 and 4909, were identified as candidate metazachlor-degrading genes. These findings lay the groundwork for further investigations into microbial biodegradation and bioremediation of metaldehyde and metazachlor. The methodological approach used could also provide valuable insights for future research on microbial xenobiotic biodegradation and horizontal gene transfer

LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

Migration after union dissolution in the United States:The role of non-resident family

Separation from a spouse or cohabiting partner is associated with a high likelihood of moving, even over long distances. In this paper, we use longitudinal data from the Panel Study of Income Dynamics for the United States to analyze the role of non-resident family in the migration of separated people immediately after and in the years following union dissolution. We explore both migration in general and return migration among separated people, drawing comparisons to married and never-married people. We find that having parents, children, or siblings living close by substantially deters migration, especially among separated people. We also find marked positive effects of having family members in the county where the respondent grew up on the likelihood of returning there. Separated people are especially likely to return, compared to others, if they have parents in their county of origin. Furthermore, a lack of an effect of years of education on migration, and a negative effect of this variable on return migration, suggest that migration after separation is less related to human-capital considerations than other types of migration