90 research outputs found
Rationalization in the Canadian Retail Gasoline Industry: The Role of Environmental Regulations
The number of gasoline stations in Canada fell by 40 percent between 1989 and 2000. Many demand and competition related explanations have been offered for this rationalization, while industry sources cite stiffer environmental regulations as a factor in station closures. In the late 1980s and early 1990s most Canadian provinces adopted regulations requiring that unprotected petroleum storage tanks be upgraded or replaced according to a schedule based on the age of the tank and that nearby unprotected tanks also be upgraded or removed. In this paper, we exploit provincial differences in the timing of these regulations to examine the role of upgrade and removal regulations on the timing and degree of station shutdown in 12 cities across the country.petroleum storage; rationalization; retail gasoline; underground storage tanks; environmental regulations
The Overpricing Problem: Moral Hazard and Franchises
We hypothesize that moral hazard is an important factor in explaining the under performance of firms, identified by Ritter (1991), following initial public offerings (IPOs). We test this hypothesis by comparing post-IPO returns of franchised and non-franchised firms. Franchised IPOs, whose franchise agreements mitigate the moral hazard problems that arise from the dilution of ownership following an IPO, outperform their non-franchised, matched counterpart IPOs over five years in the aftermarket.IPO; moral hazard; overpricing; franchises
Tetrahymena Thermophila as an Indicator Species for Climate Change
Tetrahymena thermophila are free-living, nonparasitic unicellular eukaryotic organisms that are generally representative of other microorganisms. For this experiment, we were interested in measuring the change in gene expression caused by stressing Tetrahymena, specifically by increasing the culture temperature. In our studies, gene expression was observed by measuring mitotic rates, acetylation and methylation of histones, and mitochondrial biogenesis in response to heat shock. We used a variety of techniques to accomplish this, including cell counting via hemocytometer, immunofluorescence visualization and quantitation, and staining with MitoTracker™. Tetrahymena\u27s response to the increase in environmental temperatures could give us some insight into the effects of climate change on unicellular organisms
SIC-8000 versus hetastarch as a submucosal injection fluid for endoscopic mucosal resection: a randomized controlled trial
Background and Aims
Viscous solutions provide a superior submucosal cushion for endoscopic mucosal resection (EMR). SIC-8000 (Eleview, Aries Pharmaceuticals, La Jolla, Calif) is a commercially available FDA approved solution but hetastarch is also advocated. We performed a randomized trial comparing SIC-8000 to hetastarch as submucosal injection agents for colorectal EMR.
Methods
This was a single-center double-blinded randomized controlled trial performed at a tertiary referral center. Patients were referred to our center with flat or sessile lesions measuring ≥15 mm in size. The primary outcome measures were the Sydney Resection Quotient (SRQ) and the rate of en bloc resections. Secondary outcomes were total volume needed for a sufficient lift, number of resected pieces, and adverse events.
Results
There were 158 patients with 159 adenomas (84 SIC-8000 and 75 hetastarch) and 57 serrated lesions (30 SIC-8000 and 27 hetastarch). SRQ was significantly better in the SIC-8000 group compared with hetastarch group (9.3 vs 8.1, p=0.001). There was no difference in the proportion of lesions with en bloc resections. The total volume of injectate was significantly lower with SIC-8000 (14.8 mL vs 20.6 mL, p=0.038)
Conclusions
SIC-8000 is superior to hetastarch for use during EMR in terms of SRQ and total volume needed, although the absolute differences were small
High-definition colonoscopy versus Endocuff versus EndoRings versus Full-Spectrum Endoscopy for adenoma detection at colonoscopy: a multicenter randomized trial
Background
Devices used to improve polyp detection during colonoscopy have seldom been compared with each other.
Methods
We performed a 3-center prospective randomized trial comparing high-definition (HD) forward-viewing colonoscopy alone to HD with Endocuff to HD with EndoRings to the Full Spectrum Endoscopy (FUSE) system. Patients were age ≥50 years and had routine indications and intact colons. The study colonoscopists were all proven high-level detectors. The primary endpoint was adenomas per colonoscopy (APC)
Results
Among 1,188 patients who completed the study, APC with Endocuff (APC Mean ± SD 1.82 ± 2.58), EndoRings (1.55 ± 2.42), and standard HD colonoscopy (1.53 ± 2.33) were all higher than FUSE (1.30 ± 1.96,) (p<0.001 for APC). Endocuff was higher than standard HD colonoscopy for APC (p=0.014) . Mean cecal insertion times with FUSE (468 ± 311 seconds) and EndoRings (403 ± 263 seconds) were both longer than with Endocuff (354 ± 216 seconds) (p=0.006 and 0.018, respectively).
Conclusions
For high-level detectors at colonoscopy, forward-viewing HD instruments dominate the FUSE system, indicating that for these examiners image resolution trumps angle of view. Further, Endocuff is a dominant strategy over EndoRings and no mucosal exposure device on a forward-viewing HD colonoscope
High interannual variability in connectivity and genetic pool of a temperate clingfish matches oceanographic transport predictions
Adults of most marine benthic and demersal fish are site-attached, with the dispersal of their larval stages ensuring connectivity among populations. In this study we aimed to infer spatial and temporal variation in population connectivity and dispersal of a marine fish species, using genetic tools and comparing these with oceanographic transport. We focused on an intertidal rocky reef fish species, the shore clingfish Lepadogaster lepadogaster, along the southwest Iberian Peninsula, in 2011 and 2012. We predicted high levels of self-recruitment and distinct populations, due to short pelagic larval duration and because all its developmental stages have previously been found near adult habitats. Genetic analyses based on microsatellites countered our prediction and a biophysical dispersal model showed that oceanographic transport was a good explanation for the patterns observed. Adult sub-populations separated by up to 300 km of coastline displayed no genetic differentiation, revealing a single connected population with larvae potentially dispersing long distances over hundreds of km. Despite this, parentage analysis performed on recruits from one focal site within the Marine Park of Arrabida (Portugal), revealed self-recruitment levels of 2.5% and 7.7% in 2011 and 2012, respectively, suggesting that both long-and short-distance dispersal play an important role in the replenishment of these populations. Population differentiation and patterns of dispersal, which were highly variable between years, could be linked to the variability inherent in local oceanographic processes. Overall, our measures of connectivity based on genetic and oceanographic data highlight the relevance of long-distance dispersal in determining the degree of connectivity, even in species with short pelagic larval durations
Chorioamnionitis: Case definition & guidelines for data collection, analysis, and presentation of immunization safety data
Chorioamnionitis is a term encompassing a broad spectrum of
disease during pregnancy that is characterized by inflammation
and/or infection of intrauterine structures such as the placenta,
the chorion and amnion. The clinical presentation
of chorioamnionitis can vary based on clinical, microbiologic, and
histologic factors which interact and overlap to varying degrees
Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans
Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have
fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in
25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16
regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of
correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP,
while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in
Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium
(LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region.
Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant
enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the
refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa,
an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of
PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent
signals within the same regio
Neuroanatomy of fragile X syndrome is associated with aberrant behavior and the fragile X mental retardation protein (FMRP)
To determine how neuroanatomic variation in children and adolescents with fragile X syndrome is linked to reduced levels of the fragile X mental retardation-1 protein and to aberrant cognition and behavior
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