Exclusion Processes and boundary conditions

A family of boundary conditions corresponding to exclusion processes is introduced. This family is a generalization of the boundary conditions corresponding to the simple exclusion process, the drop-push model, and the one-parameter solvable family of pushing processes with certain rates on the continuum [1-3]. The conditional probabilities are calculated using the Bethe ansatz, and it is shown that at large times they behave like the corresponding conditional probabilities of the family of diffusion-pushing processes introduced in [1-3].Comment: 11 pages, LaTeX2

Carbon dynamics of a warm season turfgrass using the eddy-covariance technique

Despite their ubiquitous presence in the urban landscape throughout the United States, scant attention has been given to evaluate the magnitude of net carbon balance from turfgrasses. Warm season turfgrasses, in particular, have largely been understudied for their carbon sequestration potential. With questions being frequently raised on the environment friendliness of warm season turfgrasses, detailed and robust studies focusing on the carbon behavior of such systems are warranted. This study delves into the carbon balance of ‘Tifway’ bermudagrass, the extensively used warm-season turfgrass in Georgia and other subtropical and warm temperate areas. Using the eddy-covariance method, the amount of CO2 captured by a highly managed turfgrass system was measured by deploying two eddy-covariance systems for the study period of 31 months. The results show that ‘Tifway’ bermudagrass is a net sink of carbon, sequestering it at the rate of 4.51–5.15 Mg C ha−1 yr−1. The turf canopy as well as management activities carried out in the farm appear to have a powerful influence on the carbon behavior of the turf. Seasonal and monthly fluxes suggest that turf is an efficient assimilator of carbon during its active growth period of summer and fall months. The results show that the turf sequestered higher amounts of carbon than many agricultural crop systems, supporting the assertion that it is an efficient assimilator of atmospheric carbon. © 201

A comparative evaluation of dried activated sludge and mixed dried activated sludge with rice husk silica to remove hydrogen sulfide.

The aim of this study was to investigate the effectiveness of dried activated sludge (DAS) and mixed dried activated sludge with rice husk silica (DAS & RHS) for removal of hydrogen sulfide (H2S). Two laboratory-scale filter columns (packed one litter) were operated. Both systems were operated under different conditions of two parameters, namely different inlet gas concentrations and different inlet flow rates. The DAS & RHS packed filter showed more than 99.96% removal efficiency (RE) with empty bed residence time (EBRT) of 45 to 90 s and 300 mg/L inlet concentration of H2S. However, the RE decreased to 96.87% with the EBRT of 30 s. In the same condition, the DAS packed filter showed 99.37% RE. Nonetheless, the RE was shown to have dropped to 82.09% with the EBRT of 30 s. The maximum elimination capacity (EC) was obtained in the DAS & RHS packed filter up to 52.32 g/m3h, with the RE of 96.87% and H2S mass loading rate of 54 g/m3h. The maximum EC in the DAS packed filter was obtained up to 44.33 g/m3h with the RE of 82.09% and the H2S mass loading rate of 54 g/m3h. After 53 days of operating time and 54 g/m3h of loading rates, the maximum pressure drop reached to 3.0 and 8.0 (mm H2O) for the DAS & RHS packed and DAS packed filters, respectively. Based on the findings of this study, the DAS & RHS could be considered as a more suitable packing material to remove H2S

Seismic Performance Assessment in Dense Urban Environments: Evaluation of Nonlinear Building-Foundation Systems Using Centrifuge Tests

In dense urban areas, buildings are generally constructed in clusters, forming city blocks. New buildings are designed assuming their response is independent of adjacent buildings, which ignores potentially important structure-soil-structure-interaction (SSSI) effects. Although a few studies have revealed the significance of SSSI effects, validated simulation and design tools do not exist. In this paper, we present the results from the first in a series of centrifuge tests intended to investigate SSSI effects. Results herein are focused on the design and measured response of two model building-foundation systems placed on dense dry Nevada sand and tested at 55-g. The two models represent prototypical nine-story and three-story special moment resisting frame buildings, with the former structure supported by a three-level basement-mat and the later on isolated spread footings. Nonlinear response-history simulations are performed to aid in the design of the models, with particular attention to reproducing prototype building periods and nonlinear characteristics. Yielding of the model buildings is achieved using custom-designed fuses placed strategically throughout the superstructures. At present, the two models are placed as far apart as possible to characterize soil-structure interaction on individual buildings; subsequent experiments will move the structures in near proximity, allowing direct experimental assessment of structuresoil- structure-interaction

Earthquake Input Motions and Seismic Site Response in a Centrifuge Test Examining SFSI Effects

This paper describes the ground motion selection process and reports observed seismic site response and SFSI effects during a dynamic centrifuge test (Test-1). The centrifuge test is the first in a series of tests examining the effects of SFSI in dense urban environments. The objective of Test-1 is to examine SFSI effects for two structures that are located a significant distance apart and essentially isolated. The model structures represent a three-story building founded on spread footings and a nine-story structure founded on a threestory basement. The structures are sited on a dry, dense bed of Nevada Sand. The centrifuge model is subjected to a series of shaking events that represent near-fault and “ordinary” ground motions at a site in Los Angeles. Results show that site periods degrade as ground motion intensity increases with more pronounced degradation observed for near-fault ground motions as compared with ordinary ground motions. Additionally, the results indicate the importance of kinematic effects of embedded structures when considering SFSI effects

Characterisation of breast fine-needle aspiration biopsies by centrosome aberrations and genomic instability

Recent studies have suggested that aneuploidy in malignant tumours could be a consequence of centrosome aberrations. Using immunofluorescence analysis with an antibody against γ-tubulin and DNA image cytometry, we measured centrosome aberrations and DNA ploidy patterns in fine-needle aspiration biopsies (FNABs) of 58 breast lesions. Benign lesions did not show any centrosome aberrations. DNA diploid carcinomas showed a mean percentage of cells with centrosomal defects of 2.1%. The aneuploid invasive carcinomas could be divided into two subgroups by their significantly (P=0.0003) different percentage of cells with centrosome aberrations (2.0 and 10.3%, respectively) and their significantly (P=0.0003) different percentage of cells with nonmodal DNA content values determined by the Stemline Scatter Index (SSI), a measure of genomic instability. The percentage of cells with centrosome aberrations demonstrated a positive, linear correlation with the corresponding SSI (r=0.82, P<0.0001) and loss of tissue differentiation (r=0.78, P<0.0001). Our results indicate the percentage of cells with centrosome aberrations as being sufficient to divide the investigated tumours into three significantly different groups: benign lesions with no centrosomal aberrations, and two malignant tumour types with mean values of 2.1 and 9.6% of centrosomal defects, respectively. Together, these results demonstrate that centrosome aberrations correlate with genomic instability and loss of tissue differentiation. Furthermore, this study shows the feasibility of centrosomal analysis in FNAB of the breast and suggests centrosomal aberrations as possessing diagnostic and prognostic value

Faecal calprotectin: factors affecting levels and its potential role as a surrogate marker for risk of development of Crohn's Disease.

BACKGROUND: Faecal calprotectin (FC) is one of the most widely used non-invasive tests for the diagnosis and assessment of Crohn's disease (CD) activity. Despite this, factors other than disease activity which affect levels have not been extensively reviewed. This is of importance when using FC in the diagnostic setting but also may be of utility in studying the aetiology of disease. OBJECTIVES: Our review outlines environmental risk factors that affect FC levels influencing diagnostic accuracy and how these may be associated with risk of developing CD. FC as a surrogate marker could be used to validate risk factors established in case control studies where prospective studies are not feasible. Proof of this concept is provided by our identification of obesity as being associated with elevated FC, our subsequent confirmation of obesity as risk factor for CD and the subsequent verification in prospective studies, as well as associations of lack of physical activity and dietary fibre intake with elevated FC levels and their subsequent confirmation as risk factors in prospective studies. CONCLUSION: We believe that FC is likely to prove a useful surrogate marker for risk of developing CD. This review has given a theoretical basis for considering the epidemiological determinants of CD which to date has been missing

Steel fibre reinforced concrete for elements failing in bending and in shear

Discrete steel fibres can increase significantly the bending and the shear resistance of concrete structural elements when Steel Fibre Reinforced Concrete (SFRC) is designed in such a way that fibre reinforcing mechanisms are optimized. To assess the fibre reinforcement effectiveness in shallow structural elements failing in bending and in shear, experimental and numerical research were performed. Uniaxial compression and bending tests were executed to derive the constitutive laws of the developed SFRC. Using a cross-section layered model and the material constitutive laws, the deformational behaviour of structural elements failing in bending was predicted from the moment-curvature relationship of the representative cross sections. To evaluate the influence of the percentage of fibres on the shear resistance of shallow structures, three point bending tests with shallow beams were performed. The applicability of the formulation proposed by RILEM TC 162-TDF for the prediction of the shear resistance of SFRC elements was evaluated. Inverse analysis was adopted to determine indirectly the values of the fracture mode I parameters of the developed SFRC. With these values, and using a softening diagram for modelling the crack shear softening behaviour, the response of the SFRC beams failing in shear was predicted.Fundação para a Ciência e a Tecnologia (FCT