Showing papers by "John Wilson published in 2016"

Ambient Air Pollutants Have Adverse Effects on Insulin and Glucose Homeostasis in Mexican Americans

Abstract: OBJECTIVE Recent studies suggest that air pollution plays a role in type 2 diabetes (T2D) incidence and mortality. The underlying physiological mechanisms have yet to be established. We hypothesized that air pollution adversely affects insulin sensitivity and secretion and serum lipid levels. RESEARCH DESIGN AND METHODS Participants were selected from BetaGene ( n = 1,023), a study of insulin resistance and pancreatic β-cell function in Mexican Americans. All participants underwent DXA and oral and intravenous glucose tolerance tests and completed dietary and physical activity questionnaires. Ambient air pollutant concentrations (NO 2 , O 3 , and PM 2.5 ) for short- and long-term periods were assigned by spatial interpolation (maximum interpolation radius of 50 km) of data from air quality monitors. Traffic-related air pollution from freeways (TRAP) was estimated using the dispersion model as NO x . Variance component models were used to analyze individual and multiple air pollutant associations with metabolic traits. RESULTS Short-term (up to 58 days cumulative lagged averages) exposure to PM 2.5 was associated with lower insulin sensitivity and HDL-to-LDL cholesterol ratio and higher fasting glucose and insulin, HOMA-IR, total cholesterol, and LDL cholesterol (LDL-C) (all P ≤ 0.036). Annual average PM 2.5 was associated with higher fasting glucose, HOMA-IR, and LDL-C ( P ≤ 0.043). The effects of short-term PM 2.5 exposure on insulin sensitivity were largest among obese participants. No statistically significant associations were found between TRAP and metabolic outcomes. CONCLUSIONS Exposure to ambient air pollutants adversely affects glucose tolerance, insulin sensitivity, and blood lipid concentrations. Our findings suggest that ambient air pollutants may contribute to the pathophysiology in the development of T2D and related sequelae.

Vertebral Adaptations to Large Body Size in Theropod Dinosaurs.

Abstract: Rugose projections on the anterior and posterior aspects of vertebral neural spines appear throughout Amniota and result from the mineralization of the supraspinous and interspinous ligaments via metaplasia, the process of permanent tissue-type transformation. In mammals, this metaplasia is generally pathological or stress induced, but is a normal part of development in some clades of birds. Such structures, though phylogenetically sporadic, appear throughout the fossil record of non-avian theropod dinosaurs, yet their physiological and adaptive significance has remained unexamined. Here we show novel histologic and phylogenetic evidence that neural spine projections were a physiological response to biomechanical stress in large-bodied theropod species. Metaplastic projections also appear to vary between immature and mature individuals of the same species, with immature animals either lacking them or exhibiting smaller projections, supporting the hypothesis that these structures develop through ontogeny as a result of increasing bending stress subjected to the spinal column. Metaplastic mineralization of spinal ligaments would likely affect the flexibility of the spinal column, increasing passive support for body weight. A stiff spinal column would also provide biomechanical support for the primary hip flexors and, therefore, may have played a role in locomotor efficiency and mobility in large-bodied species. This new association of interspinal ligament metaplasia in Theropoda with large body size contributes additional insight to our understanding of the diverse biomechanical coping mechanisms developed throughout Dinosauria, and stresses the significance of phylogenetic methods when testing for biological trends, evolutionary or not.

Space- and ground-based CO2 measurements: A review

Abstract: The climate warming is mainly due to the increase in concentrations of anthropogenic greenhouse gases, of which CO2 is the most important one responsible for radiative forcing of the climate. In order to reduce the great estimation uncertainty of atmospheric CO2 concentrations, several CO2-related satellites have been successfully launched and many future greenhouse gas monitoring missions are planned. In this paper, we review the development of CO2 retrieval algorithms, spatial interpolation methods and ground observations. The main findings include: 1) current CO2 retrieval algorithms only partially account for atmospheric scattering effects; 2) the accurate estimation of the vertical profile of greenhouse gas concentrations is a long-term challenge for remote sensing techniques; 3) ground-based observations are too sparse to accurately infer CO2 concentrations on regional scales; and 4) accuracy is the primary challenge of satellite estimation of CO2 concentrations. These findings, taken as a whole, point to the need to develop a high accuracy method for simulation of carbon sources and sinks on the basis of the fundamental theorem of Earth’s surface modelling, which is able to efficiently fuse space- and ground-based measurements on the one hand and work with atmospheric transport models on the other hand.

Analysing the uncertainty of estimating forest carbon stocks in China

Abstract: . Earth surface systems are controlled by a combination of global and local factors, which cannot be understood without accounting for both the local and global components. The system dynamics cannot be recovered from the global or local controls alone. Ground forest inventory is able to accurately estimate forest carbon stocks in sample plots, but these sample plots are too sparse to support the spatial simulation of carbon stocks with required accuracy. Satellite observation is an important source of global information for the simulation of carbon stocks. Satellite remote sensing can supply spatially continuous information about the surface of forest carbon stocks, which is impossible from ground-based investigations, but their description has considerable uncertainty. In this paper, we validated the Kriging method for spatial interpolation of ground sample plots and a satellite-observation-based approach as well as an approach for fusing the ground sample plots with satellite observations. The validation results indicated that the data fusion approach reduced the uncertainty of estimating carbon stocks. The data fusion had the lowest uncertainty by using an existing method for high-accuracy surface modelling to fuse the ground sample plots with the satellite observations (HASM-S). The estimates produced with HASM-S were 26.1 and 28.4 % more accurate than the satellite-based approach and spatial interpolation of the sample plots respectively. Forest carbon stocks of 7.08 Pg were estimated for China during the period from 2004 to 2008, an increase of 2.24 Pg from 1984 to 2008, using the preferred HASM-S method.

Modelling of XCO2 Surfaces Based on Flight Tests of TanSat Instruments

Abstract: The TanSat carbon satellite is to be launched at the end of 2016. In order to verify the performance of its instruments, a flight test of TanSat instruments was conducted in Jilin Province in September, 2015. The flight test area covered a total area of about 11,000 km² and the underlying surface cover included several lakes, forest land, grassland, wetland, farmland, a thermal power plant and numerous cities and villages. We modeled the column-average dry-air mole fraction of atmospheric carbon dioxide (XCO₂) surface based on flight test data which measured the near- and short-wave infrared (NIR) reflected solar radiation in the absorption bands at around 760 and 1610 nm. However, it is difficult to directly analyze the spatial distribution of XCO₂ in the flight area using the limited flight test data and the approximate surface of XCO₂, which was obtained by regression modeling, which is not very accurate either. We therefore used the high accuracy surface modeling (HASM) platform to fill the gaps where there is no information on XCO₂ in the flight test area, which takes the approximate surface of XCO₂ as its driving field and the XCO₂ observations retrieved from the flight test as its optimum control constraints. High accuracy surfaces of XCO₂ were constructed with HASM based on the flight's observations. The results showed that the mean XCO₂ in the flight test area is about 400 ppm and that XCO₂ over urban areas is much higher than in other places. Compared with OCO-2's XCO₂, the mean difference is 0.7 ppm and the standard deviation is 0.95 ppm. Therefore, the modelling of the XCO₂ surface based on the flight test of the TanSat instruments fell within an expected and acceptable range.

Longer-Term Volunteering Impacts on Volunteers and Association Members/Participants

Abstract: This chapter reviews research on the longer-term consequences of volunteering for the volunteer as a participant or member in a voluntary membership association (MA) or in a Volunteer Service Program (VSP; see Handbook Chapter 15). Some consequences are immediate, as positive or negative felt affects/emotions from an activity (see the following Chapter 53 of this Handbook). Other consequences, more commonly the focus of volunteer impact research, are longer term, over days, months, and years, as mainly reviewed in this chapter (but also reviewed partly in Chapter 53, for longer-term happiness and well-being effects).

Simplified elastic design checks for torsionally balanced and unbalanced low-medium rise buildings in lower seismicity regions

Abstract: A simplified approach of assessing torsionally balanced (TB) and torsionally unbalanced (TU) low-medium rise buildings of up to 30 m in height is presented in this paper for regions of low-to-moderate seismicity. The Generalised Force Method of Analysis for TB buildings which is illustrated in the early part of the paper involves calculation of the deflection profile of the building in a 2D analysis in order that a capacity diagram can be constructed to intercept with the acceleration-displacement response spectrum diagram representing seismic actions. This approach of calculation on the planar model of a building which involves applying lateral forces to the building (waiving away the need of a dynamic analysis and yet obtaining similar results) has been adapted for determining the deflection behaviour of a TU building in the later part of the paper. Another key original contribution to knowledge is taking into account the strong dependence of the torsional response behaviour of the building on the periodic properties of the applied excitations in relation to the natural periods of vibration of the building. Many of the trends presented are not reflected in provisions of major codes of practices for the seismic design of buildings. The deflection behaviour of the building in response to displacement controlled (DC) excitations is in stark contrast to behaviour in acceleration controlled (AC), or velocity controlled (VC), conditions, and is much easier to generalise. Although DC conditions are rare with buildings not exceeding 30 m in height displacement estimates based on such conditions can be taken as upper bound estimates in order that a conservative prediction of the displacement profile at the edge of a TU building can be obtained conveniently by the use of a constant amplification factor to scale results from planar analysis.

The application of electromagnetic measurements for the assessment of skin passed steel samples

Abstract: This paper begins by exploring the relationship between magnetic properties such as coercive field, RMS Magnetic Barkhausen Noise (MBN), initial and differential permeability and percentage elongation of skin passed samples for three different steels; interstitial free, micro alloyed and dual phase. A closed magnetic loop system is used to measure the fundamental magnetisation properties and a system based on an impedance analyser and a cylindrical coil is used to determine low field differential permeability. The results show that coercive field increases consistently with increasing percentage elongation for all three steels, as increasing material hardness causes an increase in magnetic hardness and a corresponding increase in coercive field. This effect levels off at higher values as dislocation density saturates. As would be expected, the inverse trend is observed for differential permeability. Similar results are also reported for MBN and initial and low field differential permeability measurements for the interstitial free and dual phase steel, but the behaviour for the micro alloyed samples appears to be more complex. Finally, the paper considers the response of two on-line measurement systems that exploit these magnetic relations. The first system applies pulse excitation and measures the resulting remnant magnetisation and the second analyses the harmonic response from AC excitation. Both systems can detect microstructural changes associated with varying magnetic properties during strip production.

Yield Penetration Displacement of Lightly Reinforced Concrete Columns

Abstract: Yield penetration or slip deformation is characterised by a rigid body rotation of the column associated with a gap opening at the column-foundation interface from the penetration of inelastic strain in the tensile reinforcement embedded in the foundation. The rigid-body end rotation increases the total drift significantly and has to be separated from flexural deformation obtained from curvature distribution over the column height. The yield penetration deformation model is developed based on a displacement-controlled principle using a new approach where the local steel strain as a function of the column global displacement is presented. In order to solve the strain incompatibility between steel and concrete, a correlation between compressive concrete strain and neutral axis depth is developed and a complete algorithm is presented that modifies the fibre cross section analysis to operate under curvature control as a function of top column displacement instead of strain control.

Structural behaviour of ceiling diaphragms in steel-framed residential structures

Abstract: In residential structures, the ceiling structure is utilised as a structural diaphragm to transfer the lateral loads acting on the roof to the bracing walls. In steel-framed houses, the ceiling diaphragm is typically made of plasterboard lining screwed into steel ceiling battens which in turn are attached to the bottom chords of roof trusses. While the ceiling diaphragm is relied upon to perform an important structural function, there is very limited guidance available on the structural behaviour of such diaphragms. This paper presents results from experimental and analytical models which provide strength and stiffness data for typical diaphragms. These data can be used to carry out rational design for such diaphragms.

Meaning-making in bereavement counselling: clients’ assimilation of grief experiences

Abstract: Inspired by the work of Parkes (1971), Neimeyer (2001) and Attig (2001), who posit that grieving is a process of meaning-making and adaptation, the authors aimed to observe how clients make effective use of bereavement counselling. Adopting a theory-building case study approach (Stiles, 2007), the authors began with a testable theory; that grief resolution requires learnt adaptation to loss, which in turn involves an observable process of assimilation. The authors suggest that this is analogous to constructivist learning seen in children (Piaget, 1952), a view supported by the psychology of personal constructs developed as a model of psychotherapy by Kelly (1963), and further investigated by Neimeyer (2009) and Janoff-Bulman (1992). An observational protocol was devised which reconciled scientific positivism with relativist methodologies (Wilson, Gabriel, & James, 2014). The counselling sessions of five bereaved clients were recorded and transcribed. The transcripts, supported by the lead researcher’s immersion in the session recordings, were subjected to assimilation analysis (Varvin & Stiles, 1999). Because the lead researcher was also the counsellor, inter-rater reliability measures were used to mitigate observer bias. The initial theory was borne out. Each client was observed assimilating his/her life changes. In collating transcribed extracts, three categories were identified: managing the grief, accepting the circumstances of the death, and developing a continuing bond (Klass, Silverman, & Nickman, 1996). Using Stiles’ (2001) Assimilation of Problematic Experiences Scale as a template, the authors arrived at an eight point scale which described a sequence of adaptation to loss and grief.

Shaking table study of a brick veneer house subjected to blast vibrations

Abstract: This article reports on a unique shaking table test examining the performance of a single-room house to simulated blast vibrations. The unreinforced masonry veneer specimen that is constructed to r...

Interaction analysis of waffle slabs supporting houses on expansive soil

Abstract: This study investigates the soil–slab interaction for waffle slabs supporting residential structures on highly expansive soils. Interaction modelling techniques are reviewed, and the implications of the modelling assumptions typically employed are discussed. More realistic modelling assumptions are proposed, and their effects are investigated. For this purpose, advanced incremental/inelastic FE models are developed in OpenSees to capture the slab structural response during the history of soil movement in heave condition. Soil profile (mound shape), soil stiffness profile and soil–slab contact are updated corresponding to growing mound. The study provides an insight into the resulting changes in bending moment and deformation demands on such slabs. It is found that the conventional assumption of a constant soft soil stiffness coupled with a stepped transition to that of hard soil is generally unconservative. The analyses also suggest that predefining a critical scenario and disregarding the history of loading is not necessarily conservative.

Collapse risk assessment of CFRP-repaired earthquake-damaged RC columns using hybrid simulation

Abstract: Hybrid simulation combines computer simulations with experimental testing to provide a powerful platform for large-scale experimental investigation of the seismic response of structures through collapse. This paper presents an application of hybrid simulation for tracing the seismic response of a limitedductility reinforced-concrete (RC) column through collapse and evaluating the capability of carbon-fibre reinforced polymer (CFRP) repair on rehabilitating the damaged column to its initial collapse resistance capacity. A state-of-the-art hybrid testing facility, referred to as the Multi-Axis Substructure Testing (MAST) system, was used to simulate complex time-varying six-degrees-of-freedom (6-DOF) boundary effects on the physical specimens using mixed load/deformation modes. Based on the experimental results, a comparative collapse risk assessment of the initial and repaired column was conducted, which illustrates the effectiveness of using CFRP-repair to restore and improve the collapse resistance of earthquake-damaged RC structures.