Ahead of the game or behind the curve? (or, why building our confidence in models is essential)

Three-dimensional geological models provide geologists with a medium through which to convey their understanding of the subsurface. In the UK, geological modelling has recently been applied to several infrastructure projects, such as high speed railways and tunneling projects. Typically, models are used to indicate ground conditions at the initial planning stage of a project. For more proactive users, the model can also act as a medium through which to develop an evolving conceptual ground model as additional geological data and information is collected. The latter facilitates continuous improvement of geological knowledge and understanding and has the potential to enhance national geological understanding. Use of 3D data is becoming mainstream in the construction sector through the uptake of the building information model (BIM); that is a virtual 3D representation of structures that aids planning, design, scheduling, construction, maintenance and demolition. Unfortunately the application of 3D geological models appears to be lagging behind the uptake of BIM. Why is this? Are we reticent about deploying models with much less than the mm-scale accuracy afforded by BIM modelling? Or is geological uncertainty understood by professionals, and is it in fact, the geologists, who are reticent about deploying models widely, and hence are contributing to the lack of appreciation for what the models can offer to prospective users? This paper considers how we must proceed to improve confidence in 3D geological models; demonstrating the validity of the 3D medium, refining our approaches and recognising the errors may help us improve confidence in our ability to build 3D models, but moreover, perhaps it is the cultural barriers in particular, the geologist’s culture, that needs to change before we can convince the user community to embrace 3D geological modelling

Bismuth(III) Forms Exceptionally Strong Complexes with Natural Organic Matter

The use of bismuth in the society has steadily increased during the last decades, both as a substitute for lead in hunting ammunition and various metallurgical applications, as well as in a range of consumer products. At the same time, the environmental behavior of bismuth is largely unknown. Here, the binding of bismuth(III) to organic soil material was investigated using extended X-ray absorption spectroscopy (EXAFS) and batch experiments. Moreover, the capacity of suwannee river fulvic acid (SRFA) to enhance the solubility of metallic bismuth was studied in a long-term (2 years) equilibration experiment. Bismuth(III) formed exceptionally strong complexes with the organic soil material, where >99% of the added bismuth(III) was bound by the solid phase, even at pH 1.2. EXAFS data suggest that bismuth(III) was bound to soil organic matter as a dimeric Bi3+ complex where one carboxylate bridges two Bi3+ ions, resulting in a unique structural stability. The strong binding to natural organic matter was verified for SRFA, dissolving 16.5 mmol Bi per gram carbon, which largely exceeds the carboxylic acid group density of this compound. Our study shows that bismuth(III) will most likely be associated with natural organic matter in soils, sediments, and waters

Prevalence and patterns of antidepressant switching amongst Primary Care patients in the UK

Objective: Non-response to antidepressant treatment is a substantial problem in primary care, and many patients with depression require additional second-line treatments. This study aimed to examine the prevalence and patterns of antidepressant switching in the UK, and identify associated demographic and clinical factors. Method: Cohort analysis of antidepressant prescribing data from the Clinical Practice Research Datalink, a large, anonymised UK primary care database. The sample included 262,844 patients who initiated antidepressant therapy between 1 January 2005 and 31 June 2011. Results: 9.3% of patients switched to a different antidepressant product, with most switches (60%) occurring within 8 weeks of the index date. The proportion switching was similar for selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants and other antidepressants (9.3%, 9.8% and 9.2%, respectively). Most switches were to an SSRI (64.5%), and this was the preferred option regardless of initial antidepressant class. Factors predictive of switching included male gender, age, and history of self-harm and psychiatric illness. Conclusion: Over one in every 11 patients who initiates antidepressant therapy will switch medication, suggesting that initial antidepressant treatment has been unsatisfactory. Evidence to guide choice of second-line treatment for individual patients is currently limited. Additional research comparing different pharmacological and psychological second-line treatment strategies is required in order to inform guidelines and improve patient outcomes. </jats:sec

Testing Models of Intrinsic Brightness Variations in Type Ia Supernovae, and their Impact on Measuring Cosmological Parameters

For spectroscopically confirmed Type Ia supernovae we evaluate models of intrinsic brightness variations with detailed data/Monte Carlo comparisons of the dispersion in the following quantities: Hubble-diagram scatter, color difference (B-V-c) between the true B-V color and the fitted color (c) from the SALT-II light curve model, and photometric redshift residual. The data sample includes 251 ugriz light curves from the 3-season Sloan Digital Sky Survey-II, and 191 griz light curves from the Supernova Legacy Survey 3-year data release. We find that the simplest model of a wavelength-independent (coherent) scatter is not adequate, and that to describe the data the intrinsic scatter model must have wavelength-dependent variations. We use Monte Carlo simulations to examine the standard approach of adding a coherent scatter term in quadrature to the distance-modulus uncertainty in order to bring the reduced chi2 to unity when fitting a Hubble diagram. If the light curve fits include model uncertainties with the correct wavelength dependence of the scatter, we find that the bias on the dark energy equation of state parameter $w$ is negligible. However, incorrect model uncertainties can lead to a significant bias on the distance moduli, with up to ~0.05 mag redshift-dependent variation. For the recent SNLS3 cosmology results we estimate that this effect introduces an additional systematic uncertainty on $w$ of ~0.02, well below the total uncertainty. However, this uncertainty depends on the samples used, and thus this small $w$-uncertainty is not guaranteed in future cosmology results.Comment: accepted by Ap

Evidence of the mineral ZnHAsO4 center dot H2O, koritnigite, controlling As(V) and Zn(II) solubility in a multi-contaminated soil

Assessing element speciation and solubility control mechanisms in multi-contaminated soils poses great challenges. In this study, we examined the speciation and mechanisms controlling the solubility of As and Zn in a soil historically contaminated with As, Cu, Cr, and Zn salts used for wood preservation. The leaching behavior of dissolved species, particles, and colloids was studied in an irrigation experiment with intact soil columns. Batch experiments were used to study the solubility of dissolved species as a function of pH (2-8). The speciation of As and Zn in bulk soil and leached particles was studied with microscale X-ray fluorescence (mu-XRF) and extended Xray absorption fine structure (EXAFS) spectroscopy. Chemical speciation and solubility were evaluated by geochemical modelling. mu-XRF of bulk soil and particles showed that As and Zn were correlated in space. Bulkand mu-EXAFS of As and Zn, in combination with calculated ion activity products of possible As-Zn minerals, suggested a koritnigite (ZnHAsO4 center dot H2O) phase controlling the dissolved fraction of As(V) and Zn with an apparent log K-sp of 21.9 +/- 0.46. This phase lowered the solubility of As by almost two orders of magnitude in soil at pH > 5, and could therefore be of great importance at other multi-contaminated sites

A Taxonomy Framework for Maritime Cybersecurity: A Demonstration Using the Automatic Identification System

The maritime transportation system is increasingly a target of cyber attacks. This paper describes a taxonomy that supports the creation of adversarial cyber models, risk mitigation, and resiliency plans as applied to the maritime industry, using the Automatic Identification System as a specific illustration of the approach. This method has already been applied to the aviation sector; retooling it for a maritime example demonstrates its broad applicability to the transportation sector, in general

Identifying barriers to care in the Burmese and Bhutanese refugee populations of Burlington, Vermont

Introduction: Many refugees who escape persecution in their own country have trouble navigating and accessing the American health care system. Language barriers often impair effective communication, while financial challenges can be prohibitive after the eight-month government insurance subsidy for new refugees expires. In addition many refugees do not understand the concept of chronic disease, which is a concern considering the overall rise in hypertension (HTN) and type-two diabetes mellitus (T2DM) in the US population. Understanding how refugees access health care, and how well they understand chronic disease, is essential for organizations providing medical care for these populations. Little is known about how the Burmese and Bhutanese refugees experience the Vermont health care system, nor how well they understand chronic diseases such as HTN and T2DM. To address these limitations, we conducted focus groups with these two Vermont refugee populations at the Community Health Center of Burlington, Vermont (CHCB).https://scholarworks.uvm.edu/comphp_gallery/1035/thumbnail.jp

How Can I Help You?Eligibility Worker: Navigating Patients Through the Social Services Maze

Introduction: Vermont has programs to assist low income individuals in obtaining basic needs such as health insurance, food security, fuel assistance, housing and transportation. However, these services are often underutilized by eligible individuals. Major barriers to enrollment include lack of knowledge about available programs and their income cutoffs, cumbersome application processes, literacy barriers, and lack of transportation to application sites. In other states, efforts to reduce these barriers have included shortened application forms, removal of asset tests, mail-in applications, media outreach, and eligibility workers placed in outreach agencies. Many studies suggest that the presence of an eligibility worker at a community health center can help overcome some social service enrollment barriers.https://scholarworks.uvm.edu/comphp_gallery/1012/thumbnail.jp

Effects of obesity, energy restriction and neutering on the faecal microbiota of cats

Surveys report that 25–57 % of cats are overweight or obese. The most evinced cause is neutering. Weight loss often fails; thus, new strategies are needed. Obesity has been associated with altered gut bacterial populations and increases in microbial dietary energy extraction, body weight and adiposity. This study aimed to determine whether alterations in intestinal bacteria were associated with obesity, energy restriction and neutering by characterising faecal microbiota using 16S rRNA gene sequencing in eight lean intact, eight lean neutered and eight obese neutered cats before and after 6 weeks of energy restriction. Lean neutered cats had a bacterial profile similar to obese rodents and humans, with a greater abundance (P<0·05) of Firmicutes and lower abundance (P <0·05) of Bacteroidetes compared with the other groups. The greater abundance of Firmicutes in lean neutered cats was due to a bloom in Peptostreptococcaceae. Obese cats had an 18 % reduction in fat mass after energy restriction (P<0·05). Energy reduction was concurrent with significant shifts in two low-abundance bacterial genera and trends in four additional genera. The greatest change was a reduction in the Firmicutes genus, Sarcina, from 4·54 to 0·65 % abundance after energy restriction. The short duration of energy restriction may explain why few bacterial changes were observed in the obese cats. Additional work is needed to understand how neutering, obesity and weight loss are related to changes in feline microbiota and how these microbial shifts affect host physiology