Progressive cracking of masonry arch bridges

Numerous methods are available for the assessment of masonry arch bridges at the ultimate limit state. However, there is a lack of suitable methods for assessing behaviour at service levels of loading. To address this, non-linear three-dimensional finite element (FE) models that consider constitutive material models enabling progressive cracking and failure of the complete structural system were used to investigate the development of damage for three masonry arch bridges at both service levels and at the ultimate capacity. All of the elements contributing to the strength of the structure were represented in the models, including the arch barrel, spandrel, abutments, fill and surrounding soil. This allowed for consideration of the longitudinal and transverse capacities, the stiffening effects of the spandrel walls, the restraint and load distribution provided by the fill, the frictional behaviour between the masonry and fill, movement at the abutments and multiple causes of failure. While complex non-linear FE models are able to identify the ultimate load capacity there are alternative simpler approaches available for this, and it is the investigation of damage and crack propagation at service level loads where their use is of greatest benefit. </jats:p

Structural dynamic parameter identification and the effect of test techniques

PublishedAmbient and forced excitation test techniques are both widely used to dynamically identify civil engineering structures. Two floor levels of a newly constructed building, the Charles Institute at University College Dublin, were tested using both techniques. Both floor designs were identical although the layout of partitions above and below each were different. The objective of the tests was to determine the most appropriate test procedure and also to identify whether the layout of partitions contributes in a significant manner to dynamic response. It was found that at low levels of excitation, ambient test levels, the dynamic response of both floors was identical. In contrast, at higher vibration excitation levels, during forced vibration testing, the floor responses were substantially different. The differing modal parameters identified are attributed to an amplitude dependent response resulting from engagement, or not, of the partitions in the dynamic response of the system. The practical significance of this finding is that it is imperative to consider, and test at, the in-service vibration amplitude expected for a floor system. © The Society for Experimental Mechanics, Inc. 2013

Factors associated with pastoral community knowledge and occurrence of mycobacterial infections in human-animal interface areas of Nakasongola and Mubende districts, Uganda

<p>Abstract</p> <p>Background</p> <p>Nontuberculous mycobacteria (NTM) are emerging opportunistic pathogens whose role in human and animal disease is increasingly being recognized. Major concerns are their role as opportunistic pathogens in HIV/AIDS infections. The role of open natural water sources as source and livestock/wildlife as reservoirs of infections to man are well documented. This presents a health challenge to the pastoral systems in Africa that rely mostly on open natural water sources to meet livestock and human needs. Recent study in the pastoral areas of Uganda showed infections with same genotypes of NTM in pastoralists and their livestock. The aim of this study was to determine the environmental, animal husbandry and socio-demographic factors associated with occurrence and the pastoral community knowledge of mycobacterial infections at the human-environment-livestock/wildlife interface (HELI) areas in pastoral ecosystems of Uganda.</p> <p>Methods</p> <p>Two hundred and fifty three (253) individuals were subjected to a questionnaire survey across the study districts of Nakasongola and Mubende. Data were analyzed using descriptive statistics and multivariable logistic regression analysis.</p> <p>Results</p> <p>Humans sharing of the water sources with wild animals from the forest compared to savannah ecosystem (OR = 3.3), the tribe of herding pastoral community (OR = 7.9), number of rooms present in household (3-5 vs. 1-2 rooms) (OR = 3.3) were the socio-demographic factors that influenced the level of knowledge on mycobacterial infections among the pastoral communities. Tribe (OR = 6.4), use of spring vs. stream water for domestic use (OR = 4.5), presence of sediments in household water receptacle (OR = 2.32), non separation of water containers for drinking and domestic use (OR = 2.46), sharing of drinking water sources with wild animals (OR = 2.1), duration of involvement of >5 yrs in cattle keeping (OR = 3.7) and distance of household to animal night shelters (>20 meters) (OR = 3.8) were significant socio-demographic factors associated with the risk of occurrence of mycobacterioses among the pastoral communities in Uganda.</p> <p>Conclusion</p> <p>The socio-demographic, environmental and household related factors influence the risk of occurrence as well as pastoralists' knowledge of mycobacterial infections in the pastoral households at the human-environment-livestock/wildlife pastoral interface areas of Uganda.</p

Temporal variability in shell mound formation at Albatross Bay, northern Australia

We report the results of 212 radiocarbon determinations from the archaeological excavation of 70 shell mound deposits in the Wathayn region of Albatross Bay, Australia. This is an intensive study of a closely co-located group of mounds within a geographically restricted area in a wider region where many more shell mounds have been reported. Valves from the bivalve Tegillarcca granosa were dated. The dates obtained are used to calculate rates of accumulation for the shell mound deposits. These demonstrate highly variable rates of accumulation both within and between mounds. We assess these results in relation to likely mechanisms of shell deposition and show that rates of deposition are affected by time-dependent processes both during the accumulation of shell deposits and during their subsequent deformation. This complicates the interpretation of the rates at which shell mound deposits appear to have accumulated. At Wathayn, there is little temporal or spatial consistency in the rates at which mounds accumulated. Comparisons between the Wathayn results and those obtained from shell deposits elsewhere, both in the wider Albatross Bay region and worldwide, suggest the need for caution when deriving behavioural inferences from shell mound deposition rates, and the need for more comprehensive sampling of individual mounds and groups of mounds

Exploration of experiences in therapeutic groups for patients with severe mental illness: development of the Ferrara group experiences scale (FE-GES)

The study has been supported by the University of Ferrara (University Funds for Scientific Research 2008–2009

Long-Term Secondary Care Costs of Endometrial Cancer: A Prospective Cohort Study Nested within the United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS).

BACKGROUND: There is limited evidence on the costs of Endometrial Cancer (EC) by stage of disease. We estimated the long-term secondary care costs of EC according to stage at diagnosis in an English population-based cohort. METHODS: Women participating in UKCTOCS and diagnosed with EC following enrolment (2001-2005) and prior to 31st Dec 2009 were identified to have EC through multiple sources. Survival was calculated through data linkage to death registry. Costs estimates were derived from hospital records accessed from Hospital Episode Statistics (HES) with additional patient level covariates derived from case notes and patient questionnaires. Missing and censored data was imputed using Multiple Imputation. Regression analysis of cost and survival was undertaken. RESULTS: 491 of 641 women with EC were included. Five year total costs were strongly dependent on stage, ranging from £9,475 (diagnosis at stage IA/IB) to £26,080 (diagnosis at stage III). Stage, grade and BMI were the strongest predictors of costs. The majority of costs for stage I/II EC were incurred in the first six months after diagnosis while for stage III / IV considerable costs accrued after the first six months. CONCLUSIONS: In addition to survival advantages, there are significant cost savings if patients with EC are detected earlier.The analysis underpinning this study was supported with a grant from Cancer Research UK (CRUK Grant No: A16008) awarded to RL (http://www.cancerresearchuk. org/funding-for-researchers). The trial (UKCTOCS) for which the patients in this study form a subgroup was funded by the Medical Research Council, Cancer Research UK, the Department of Health and the Eve Appeal

An Extensive Circuitry for Cell Wall Regulation in Candida albicans

Protein kinases play key roles in signaling and response to changes in the external environment. The ability of Candida albicans to quickly sense and respond to changes in its environment is key to its survival in the human host. Our guiding hypothesis was that creating and screening a set of protein kinase mutant strains would reveal signaling pathways that mediate stress response in C. albicans. A library of protein kinase mutant strains was created and screened for sensitivity to a variety of stresses. For the majority of stresses tested, stress response was largely conserved between C. albicans, Saccharomyces cerevisiae, and Schizosaccharomyces pombe. However, we identified eight protein kinases whose roles in cell wall regulation (CWR) were not expected from functions of their orthologs in the model fungi Saccharomyces cerevisiae and Schizosaccharomyces pombe. Analysis of the conserved roles of these protein kinases indicates that establishment of cell polarity is critical for CWR. In addition, we found that septins, crucial to budding, are both important for surviving and are mislocalized by cell wall stress. Our study shows an expanded role for protein kinase signaling in C. albicans cell wall integrity. Our studies suggest that in some cases, this expansion represents a greater importance for certain pathways in cell wall biogenesis. In other cases, it appears that signaling pathways have been rewired for a cell wall integrity response

Loss of Guanylyl Cyclase C (GCC) Signaling Leads to Dysfunctional Intestinal Barrier

Guanylyl Cyclase C (GCC) signaling via uroguanylin (UGN) and guanylin activation is a critical mediator of intestinal fluid homeostasis, intestinal cell proliferation/apoptosis, and tumorigenesis. As a mechanism for some of these effects, we hypothesized that GCC signaling mediates regulation of intestinal barrier function.Paracellular permeability of intestinal segments was assessed in wild type (WT) and GCC deficient (GCC-/-) mice with and without lipopolysaccharide (LPS) challenge, as well as in UGN deficient (UGN-/-) mice. IFNγ and myosin light chain kinase (MLCK) levels were determined by real time PCR. Expression of tight junction proteins (TJPs), phosphorylation of myosin II regulatory light chain (MLC), and STAT1 activation were examined in intestinal epithelial cells (IECs) and intestinal mucosa. The permeability of Caco-2 and HT-29 IEC monolayers, grown on Transwell filters was determined in the absence and presence of GCC RNA interference (RNAi). We found that intestinal permeability was increased in GCC-/- and UGN-/- mice compared to WT, accompanied by increased IFNγ levels, MLCK and STAT1 activation in IECs. LPS challenge promotes greater IFNγ and STAT1 activation in IECs of GCC-/- mice compared to WT mice. Claudin-2 and JAM-A expression were reduced in GCC deficient intestine; the level of phosphorylated MLC in IECs was significantly increased in GCC-/- and UGN-/- mice compared to WT. GCC knockdown induced MLC phosphorylation, increased permeability in IEC monolayers under basal conditions, and enhanced TNFα and IFNγ-induced monolayer hyperpermeability.GCC signaling plays a protective role in the integrity of the intestinal mucosal barrier by regulating MLCK activation and TJ disassembly. GCC signaling activation may therefore represent a novel mechanism in maintaining the small bowel barrier in response to injury