Bentonite geochronology and tephrostratigraphy for litho- and chronostratigraphic refinement of fossiliferous Campanian strata in western North America

Tegan Beveridge studied weathered volcanic ash horizons within Late Cretaceous rocks in western North America. New high-precision ages and geochemical data facilitated correlation of richly fossiliferous rock units across the continent. Refined understanding of these rocks has implications for investigating dinosaur biogeography and Late Cretaceous ecosystems from Alberta to Mexico

Optimal management of urinary tract infections in older people

Urinary tract infections (UTI) occur frequently in older people. Unfortunately, UTI is commonly overdiagnosed and overtreated on the basis of nonspecific clinical signs and symptoms. The diagnosis of a UTI in the older patient requires the presence of new urinary symptoms, with or without systemic symptoms. Urinalysis is commonly used to diagnose infection in this population, however, the evidence for its use is limited. There is overwhelming evidence that asymptomatic bacteriuria should not be treated. Catheter associated urinary tract infection accounts for a significant amount of hospital-associated infection. Indwelling urinary catheters should be avoided where possible and alternatives sought. The use of narrow spectrum antimicrobial agents for urinary tract infection is advocated. Local guidelines are now widely used to reflect local resistance patterns and available agents. Guidelines need to be updated to reflect changes in antimicrobial prescribing and a move from broad to narrow spectrum antimicrobials

Food Security and Climate Change Adaptation in Guatemala

The challenges of ending hunger and adapting to the impacts of climate change are high on the global development agenda and they are highly interdependent. Managing these challenges requires understanding of physical, social, political and environmental systems, their emergent properties and their interactions across scales - from individual perspectives to global processes. The Central American Dry Corridor (CADC) is a climatologically and politically defined region running through Central America, which is considered one of the most vulnerable regions in the world to the impacts of climate change. This research presented an attempt to apply cross-disciplinary approaches to the issue of food insecurity and climate impacts in the CADC, focusing in Guatemala. Applied methods range from ethnographically informed interviews and household case studies, to quantitative analyses with regional or globally standardized indices and data including household surveys, climate observation and climate impact modelling. A complex picture of the climate-food system is constructed through this integration of methods. For example, statistical analyses at the regional or national level evidenced: the risks of severe food insecurity during household transitions towards market participation; the association between agricultural labour income and severe food insecurity experiences; the association between the severity of the mid summer drought and prevalence of stunting; the association between changes in food insecurity classification used for early warning systems and drought indices (including the duration and magnitude of the mid summer drought); and the role assets and livestock (and the capabilities they represent) play in mediating climate impact and adaptation. Of the included variables across analyses, climatic and non-climate drivers differed in their relative importance regionally within Guatemala. However, this is not a complete picture, as some key findings from the individual and household level interviews were unable to be represented and tested in analyses at this scale. The main barrier to integrating participants narratives and knowledges into protocol for broad scale assessment, monitoring and decision-making - in this research - was the way in which top-down understanding and problem framings still shape what data is systematically collected and available. Recommendations identify how transdisciplinary approaches that engage iteratively with stakeholders at all levels of design, data collection, and analysis can be applied to contribute to overcome this limitation

Characterisation of silicon-silicon hydroxide catalysis bonds for future gravitational wave detectors

The first generation of gravitational wave detectors are currently undergoing significant upgrades to increase their sensitivity by a factor of ten. These upgrades include the installation of quasi-monolithic silica suspensions in an attempt to reduce the thermal noise of the test masses and their suspensions. Fused silica fibres are welded to fused silica interface pieces, called ‘ears’, which provide suitable welding points onto the sides of the mirror when bonded to the mirror using the high strength chemical jointing technique of hydroxide-catalysis bonding. Plans are developing for the design of potential ‘future generation’ gravitational wave detectors. These detectors may operate at cryogenic temperatures to further reduce thermal noise. Silicon is a prime candidate material for use in the test masses and their suspensions because of its desirable thermo-mechanical properties in the cryogenic regime. With some adaptation, hydroxide catalysis bonding may also be a viable technique for use in third generation detectors; however, to evaluate its suitability it is essential to quantify both the strength of silicon-silicon bonds at cryogenic temperatures and the mechanical loss of such bonds, as this has a direct effect on the contributions of the bond to the overall thermal noise of a bonded suspension. To make bonding of silicon components possible, the bonding surfaces must ideally have a thin coating of SiO2, with which the hydroxide can react to form the bond. In Chapters 3 and 4, the strength of hydroxide catalysis bonds between silicon blocks at room and cryogenic temperatures is investigated. Chapter 3 investigates the minimum required thickness of SiO2 necessary for a successful bond. The bond strength, tested using a 4-point bend strength test, is found to reduce significantly with oxide layer thicknesses below 50 nm at cryogenic temperature. A Weibull analysis of the results showed a characteristic strength of approximately 41MPa at 77K and 35MPa at room temperature for samples with a minimum oxide layer of 50 nm. In chapter 4 the effect on the oxide layer deposition method and the purity of the silicon ingot on the strength of the bond are studied. Bend strength tests were performed on hydroxide-catalysis bonds formed between silicon samples of different crystallographic orientation and purity that had been oxidised using a range of methods. The three methods used were; dry thermal oxidation, ion beam sputtering and e-beam deposition. It was found that the method used influenced the strength of the resulting bond, with the e-beam deposited layers producing the weakest samples. It is postulated that the reason for the lower strength of the e-beam samples is correlated with the lower density of this type of coating compared with other coating methods. The mechanical loss of the bond between silicon cantilevers between 10K and 250K was measured in Chapter 5. The experimental set up is described, the results are presented and then analysed to establish an upper limit of 0.12 for the second bending mode below 100K. The lowest loss measured was 0.06 at 12K.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Characterisation of silicon-silicon hydroxide catalysis bonds for future gravitational wave detectors

The first generation of gravitational wave detectors are currently undergoing significant upgrades to increase their sensitivity by a factor of ten. These upgrades include the installation of quasi-monolithic silica suspensions in an attempt to reduce the thermal noise of the test masses and their suspensions. Fused silica fibres are welded to fused silica interface pieces, called ‘ears’, which provide suitable welding points onto the sides of the mirror when bonded to the mirror using the high strength chemical jointing technique of hydroxide-catalysis bonding. Plans are developing for the design of potential ‘future generation’ gravitational wave detectors. These detectors may operate at cryogenic temperatures to further reduce thermal noise. Silicon is a prime candidate material for use in the test masses and their suspensions because of its desirable thermo-mechanical properties in the cryogenic regime. With some adaptation, hydroxide catalysis bonding may also be a viable technique for use in third generation detectors; however, to evaluate its suitability it is essential to quantify both the strength of silicon-silicon bonds at cryogenic temperatures and the mechanical loss of such bonds, as this has a direct effect on the contributions of the bond to the overall thermal noise of a bonded suspension. To make bonding of silicon components possible, the bonding surfaces must ideally have a thin coating of SiO2, with which the hydroxide can react to form the bond. In Chapters 3 and 4, the strength of hydroxide catalysis bonds between silicon blocks at room and cryogenic temperatures is investigated. Chapter 3 investigates the minimum required thickness of SiO2 necessary for a successful bond. The bond strength, tested using a 4-point bend strength test, is found to reduce significantly with oxide layer thicknesses below 50 nm at cryogenic temperature. A Weibull analysis of the results showed a characteristic strength of approximately 41MPa at 77K and 35MPa at room temperature for samples with a minimum oxide layer of 50 nm. In chapter 4 the effect on the oxide layer deposition method and the purity of the silicon ingot on the strength of the bond are studied. Bend strength tests were performed on hydroxide-catalysis bonds formed between silicon samples of different crystallographic orientation and purity that had been oxidised using a range of methods. The three methods used were; dry thermal oxidation, ion beam sputtering and e-beam deposition. It was found that the method used influenced the strength of the resulting bond, with the e-beam deposited layers producing the weakest samples. It is postulated that the reason for the lower strength of the e-beam samples is correlated with the lower density of this type of coating compared with other coating methods. The mechanical loss of the bond between silicon cantilevers between 10K and 250K was measured in Chapter 5. The experimental set up is described, the results are presented and then analysed to establish an upper limit of 0.12 for the second bending mode below 100K. The lowest loss measured was 0.06 at 12K

Thermocrinis minervae sp. nov., A Hydrogen and Sulfur-oxidizing, Thermophilic Member of the Aquificales from a Costa Rican Terrestrial Hot Spring

A thermophilic bacterium, designated strain CR11T , was isolated from a filamentous sample collected from a terrestrial hot spring on the south-western foothills of the Rincón volcano in Costa Rica. The Gram-negative cells are approximately 2.4–3.9 mm long and 0.5–0.6 mm wide and are motile rods with polar flagella. Strain CR11T grows between 65 and 85 6C (optimum 75 6C, doubling time 4.5 h) and between pH 4.8 and 7.8 (optimum pH 5.9–6.5). The isolate grows chemolithotrophically with S0 , S2O2{ 3 or H2 as the electron donor and with O2 (up to 16 %, v/v) as the sole electron acceptor. The isolate can grow on mannose, glucose, maltose, succinate, peptone, Casamino acids, starch, citrate and yeast extract in the presence of oxygen (4 %) and S0 . Growth occurs only at NaCl concentrations below 0.4 % (w/v). The G+C content of strain CR11T is 40.3 mol%. Phylogenetic analysis of the 16S rRNA gene sequence places the strain as a close relative of Thermocrinis ruber OC 1/4T (95.7 % sequence similarity). Based on phylogenetic and physiological characteristics, we propose the name Thermocrinis minervae sp. nov., with CR11T (5DSM 19557T 5ATCC BAA-1533T ) as the type strain

The Role of Fish in the First 1,000 Days in Zambia

Fish is especially rich in essential omega-3 long-chain polyunsaturated fatty acids and micronutrients, including bioavailable calcium, iron and zinc. Fish features prominently in the diet of most, especially poor, Zambians. Despite this, its significance in the diet of women and children in the first 1,000 days is not well understood. Our current knowledge of the nutrient content of commonly consumed fish species in Zambia is synthesised. The importance of fish in food and nutrition security of rural and urban households and the impact of intra-household distribution on nutrient intake from fish, especially among pregnant and lactating women and children 6–23 months of age, are explored in this article. Key knowledge gaps are identified, and research priorities are highlighted. Recommendations are provided on policy, communications and technological initiatives to maximise the role fish can play in the First 1000 Most Critical Days Programme in Zambia

Effect of vitamin D supplementation on blood pressure:a systematic review and meta-analysis incorporating individual patient data

D-PRESSURE Collaboration: et al.[Importance]: Low levels of vitamin D are associated with elevated blood pressure (BP) and future cardiovascular events. Whether vitamin D supplementation reduces BP and which patient characteristics predict a response remain unclear.[Objective]: To systematically review whether supplementation with vitamin D or its analogues reduce BP.[Data Sources]: We searched MEDLINE, CINAHL, EMBASE, Cochrane Central Register of Controlled Trials, and http://www.ClinicalTrials.com augmented by a hand search of references from the included articles and previous reviews. Google was searched for gray literature (ie, material not published in recognized scientific journals). No language restrictions were applied. The search period spanned January 1, 1966, through March 31, 2014.[Study Selection]: We included randomized placebo-controlled clinical trials that used vitamin D supplementation for a minimum of 4 weeks for any indication and reported BP data. Studies were included if they used active or inactive forms of vitamin D or vitamin D analogues. Cointerventions were permitted if identical in all treatment arms.[Data Extraction and Synthesis]: We extracted data on baseline demographics, 25-hydroxyvitamin D levels, systolic and diastolic BP (SBP and DBP), and change in BP from baseline to the final follow-up. Individual patient data on age, sex, medication use, diabetes mellitus, baseline and follow-up BP, and 25-hydroxyvitamin D levels were requested from the authors of the included studies. For trial-level data, between-group differences in BP change were combined in a random-effects model. For individual patient data, between-group differences in BP at the final follow up, adjusted for baseline BP, were calculated before combining in a random-effects model.[Main Outcomes and Measures]: Difference in SBP and DBP measured in an office setting.[Results]: We included 46 trials (4541 participants) in the trial-level meta-analysis. Individual patient data were obtained for 27 trials (3092 participants). At the trial level, no effect of vitamin D supplementation was seen on SBP (effect size, 0.0 [95% CI, −0.8 to 0.8] mm Hg; P = .97; I2 = 21%) or DBP (effect size, −0.1 [95% CI, −0.6 to 0.5] mm Hg; P = .84; I2 = 20%). Similar results were found analyzing individual patient data for SBP (effect size, −0.5 [95% CI, −1.3 to 0.4] mm Hg; P = .27; I2 = 0%) and DBP (effect size, 0.2 [95% CI, −0.3 to 0.7] mm Hg; P = .38; I2 = 0%). Subgroup analysis did not reveal any baseline factor predictive of a better response to therapy.[Conclusions and Relevance]: Vitamin D supplementation is ineffective as an agent for lowering BP and thus should not be used as an antihypertensive agent.Peer reviewe

Acceptability and feasibility of magnetic femoral nerve stimulation in older, functionally impaired patients

Abstract Objective Magnetic femoral nerve stimulation to test muscle function has been largely unexplored in older people. We assessed acceptability, feasibility, along with reproducibility and correlation with other physical function measures. Results Study 1 recruited older people with sarcopenia. Stimulation was performed at baseline and 2 weeks along with six minute walk (6MW), maximum voluntary quadriceps contraction, short physical performance battery and grip strength. Acceptability was measured using visual analog scales. Study 2 used baseline data from a trial of older people. We correlated stimulation results with 6MW, maximal voluntary contraction and muscle mass. Maximum quadriceps twitch tension was measured in both studies, evoked using biphasic magnetic stimulation of the femoral nerve. In study 1 (n = 12), magnetic stimulation was well tolerated with mean discomfort rating of 9% (range 0–40%) on a visual analog scale. Reproducibility was poor (intraclass correlation coefficient 0.06; p = 0.44). Study 2 (n = 64) showed only weak to moderate correlations for maximum quadriceps twitch tension with other measures of physical function (6 minute walk test r = 0.24, p = 0.06; maximal voluntary contraction r = 0.26; p = 0.04). We conclude that magnetic femoral nerve stimulation is acceptable and feasible but poorly reproducible in older, functionally impaired people

Crop modelling: towards locally relevant and climate-informed adaptation

A gap between the potential and practical realisation of adaptation exists: adaptation strategies need to be both climate-informed and locally relevant to be viable. Place-based approaches study local and contemporary dynamics of the agricultural system, whereas climate impact modelling simulates climate-crop interactions across temporal and spatial scales. Crop-climate modelling and place-based research on adaptation were strategically reviewed and analysed to identify areas of commonality, differences, and potential learning opportunities to enhance the relevance of both disciplines through interdisciplinary approaches. Crop-modelling studies have projected a 7–15% mean yield change with adaptation compared to a non-adaptation baseline (Nature Climate Change 4:1–5, 2014). Of the 17 types of adaptation strategy identified in this study as place-based adaptations occurring within Central America, only five were represented in crop-climate modelling literature, and these were as follows: fertiliser, irrigation, change in planting date, change in cultivar and area cultivated. The breath and agency of real-life adaptation compared to its representation in modelling studies is a source of error in climate impact simulations. Conversely, adaptation research that omits assessment of future climate variability and impact does not enable to provide sustainable adaptation strategies to local communities so risk maladaptation. Integrated and participatory methods can identify and reduce these sources of uncertainty, for example, stakeholder’s engagement can identify locally relevant adaptation pathways. We propose a research agenda that uses methodological approaches from both the modelling and place-based approaches to work towards climate-informed locally relevant adaptation