251 research outputs found
Explaining Cost Overruns of Large-Scale Transportation Infrastructure Projects using a Signalling Game
Strategic behaviour is one of the main explanations for cost overruns. It can
theoretically be supported by agency theory, in which strategic behaviour is
the result of asymmetric information between the principal and agent. This
paper gives a formal account of this relation by a signalling game. This is a
game with incomplete information which considers the way in which parties
anticipate upon other parties' behaviour in choosing a course of action. The
game shows how cost overruns are the result of an inappropriate signal. This
makes it impossible for the principal to distinguish between the types of
agents, and hence, allows for strategic behaviour. It is illustrated how cost
overruns can be avoided by means of two policy measures, e.g. an accountability
structure and benchmarking
The predictive role of biomarkers and genetics in childhood asthma exacerbations
Asthma exacerbations are associated with significant childhood morbidity and mortality. Recurrent asthma attacks contribute to progressive loss of lung function and can sometimes be fatal or nearâfatal, even in mild asthma. Exacerbation prevention becomes a primary target in the management of all asthmatic patients. Our work reviews current advances on exacerbation predictive factors, focusing on the role of nonâinvasive biomarkers and genetics in order to identify subjects at higher risk of asthma attacks. Easyâtoâperform tests are necessary in children; therefore, interest has increased on samples like exhaled breath condensate, urine and saliva. The variability of biomarker levels suggests the use of seriate measurements and composite markers. Genetic predisposition to childhood asthma onset has been largely investigated. Recent studies highlighted the influence of single nucleotide polymorphisms even on exacerbation susceptibility, through involvement of both intrinsic mechanisms and geneâenvironment interaction. The role of molecular and genetic aspects in exacerbation prediction supports an individualâshaped approach, in which followâup planning and therapy optimization take into account not only the severity degree, but also the risk of recurrent exacerbations. Further efforts should be made to improve and validate the application of biomarkers and genomics in clinical settings
Ultrasound to address medullary sponge kidney: A retrospective study
Background: Medullary sponge kidney (MSK) is a rare disease characterized by cystic dilatation of papillary collecting ducts. Intravenous urography is still considered the gold standard for diagnosis. We identified a cohort of patients from our outpatient clinic with established diagnosis of MSK to outline some ultrasonographic characteristics that may help establish a diagnosis. Methods: We conducted a retrospective study of patients seen between January 1st 2009 and January 1st 2019 in our clinic. Out of 4321 patients, 18 had a diagnosis of MSK. We reviewed their clinical and family history, laboratory data and imaging studies. Specifically, we focused on ultrasound imaging. Results: Patients were referred to our outpatient clinic because of renal impairment (44%), family history of nephropathy (17%), nephrolithiasis or an established diagnosis of MSK (39%). Seventy-two percent of patients presented with chronic kidney disease, 22% required hemodialysis. Urinary tract infections (44%), nephrolithiasis (33%), microscopic hematuria (50%) and proteinuria (44%) were reported. Seven patients underwent computed tomography; all of them received ultrasound. Ultrasound examination showed bilateral renal cysts, usually small and located in the renal medulla, and microcalcifications located in the medulla or within the cysts. Conclusion: We identified a peculiar tetrad associated with MSK: 1) hypoechoic medullary areas, 2) hyperechoic spots, 3) microcystic dilatation of papillary zone, 4) multiple calcifications (linear, small stones or calcified intracystic sediment) in each papilla. The presence of this diagnostic tetrad, added to laboratory data and clinical history, could be helpful in the differential diagnosis to identify patients with MSK
Pneumococcal Polysaccharide Vaccine Ameliorates Murine Lupus
Current guidelines encourage administering pneumococcal vaccine Prevnar-13 to patients with lupus, but whether such vaccinations affect disease severity is unclear. To address this issue, we treated 3-month-old MRL-lpr mice, that spontaneously develop a lupus-like syndrome, with Prevnar-13 or vehicle control. After 3 months, we quantified circulating anti-Pneumococcal polysaccharide capsule (PPS) antibodies and signs of disease severity, including albuminuria, renal histology and skin severity score. We also compared immunophenotypes and function of T and B cells from treated and untreated animals. Prevnar-13 elicited the formation of anti-pneumococcal IgM and IgG. Prevnar-13 treated animals showed reduced albuminuria, renal histological lesions, and milder dermatitis compared to vehicle-treated controls. Mitigated disease severity was associated with reduced and increased T follicular helper cells (TFH) and T follicular regulatory cells (TFR), respectively, in Prevnar-treated animals. T cells from Prevnar-13 vaccinated mice showed differential cytokine production after aCD3/aCD28 stimulation, with significantly decreased IL-17 and IL-4, and increased IL-10 production compared to non-vaccinated mice. In conclusion, pneumococcal vaccination elicits anti-pneumococcal antibody response and ameliorates disease severity in MRL-lpr mice, which associates with fewer TFH and increased TFR. Together, the data support use of Prevnar vaccination in individuals with SLE
autologous pancreatic islet transplantation in human bone marrow diabetes 2013 62 3523 3531
In the article listed above, there is an error in Fig. 3. In panel B , the immunohistochemical staining of insulin ( top middle panel
OpenWorm: an open-science approach to modeling Caenorhabditis elegans.
OpenWorm is an international collaboration with the aim of understanding how the behavior of Caenorhabditis elegans (C. elegans) emerges from its underlying physiological processes. The project has developed a modular simulation engine to create computational models of the worm. The modularity of the engine makes it possible to easily modify the model, incorporate new experimental data and test hypotheses. The modeling framework incorporates both biophysical neuronal simulations and a novel fluid-dynamics-based soft-tissue simulation for physical environment-body interactions. The project's open-science approach is aimed at overcoming the difficulties of integrative modeling within a traditional academic environment. In this article the rationale is presented for creating the OpenWorm collaboration, the tools and resources developed thus far are outlined and the unique challenges associated with the project are discussed
Putting context to numbers : a geotechnical risk trajectory to cost overrun extremism
The study investigates the cause of the unusually high cost overruns experienced
in highway project delivery in the tropical wetland setting of the Niger Delta
region of Nigeria. This is in view of the extensive literature supporting the link
between geology, the lack of geotechnical best practices and cost overruns. An
empirical profiling of cost overrun research further reveals the predominance of
mono-method studies based on survey methods, correlative analysis and archival
data modelling techniques, all of which are underlain by positivism. The study
argues that such positivist philosophies, although methodologically valid, cannot
adequately explain and provide in-depth understanding of the contextual cost
overrun drivers in highway organisations., Using a robust and thoughtfully
designed mix of methods, the paper examines the contribution of geotechnical
risks to cost overruns experienced in highway project, and demonstrates the
relevance of context in cost overrun research. Cost overrun data from
documentary sources for 61 completed highway projects in the Niger Delta are
gathered and analysed, revealing an average value of 216%, with extreme cases,
ranging up to 1925% of budgeted cost. To uncover the intrinsic contextual
drivers, 16 interviews were conducted with participants from the three highway
agencies in the region, responsible for the execution of the sampled highway
projects. Adopting a geotechnical narrative, the data is thematically analysed,
deductively and inductively. The results of the analysis identified that poor
project governance, management and procurement practices, have inhibited the
competent management of geotechnical risk, creating a propensity for extreme
cost overruns on the highway projects. The study submits the phenomenon of
cost overruns in public infrastructure projects is underlain by a complexity of
contextual social constructs, which would have been overlooked in positivists
studies. Cost overrun research therefore, needs to be contextually and
numerically anchored.
Keywords: Context, Cost overruns, Highway projects, Mixed methods, Social
Construct
Physicochemical characteristics and fatty acid composition of tomato seed oils from processing wastes
Are ant assemblages of Brazilian veredas characterised by location or habitat type?
Wetland areas in the Brazilian Cerrado, known as âveredasâ, represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation) and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season) using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species.Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted âveredasâ. Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat
MULTIPLEX SYBRÂź GREEN-REAL TIME PCR (qPCR) ASSAY FOR THE DETECTION AND DIFFERENTIATION OF Bartonella henselae AND Bartonella clarridgeiae IN CATS
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