1,662 research outputs found
The Global Financial Crisis, Inflation Rate And Stock Market Returns In Kenya
The moderating effect of events such as the 2008 Global Financial Crisis (GFC) on the relation between stock market returns and macroeconomic variables has attracted very little attention. This study investigates the extent to which the 2008 GFC moderated the relationship between inflation rate and stock market returns. The study uses month-onmonth inflation rate and year-on-year inflation rate from 1st January 1993 to 31st December 2015 and divides the sample data into pre-crisis period (from 1st January 1993 to 31st December 2007); crisis period (from 1st January 2008 to 30th June 2009); and post-crisis period (from 1st July 2009 to 31st December 2015). It uses a product-term regression model instead of the most widely applied additive regression model. Results indicate that a unit increase in the both measures of inflation rate had significant depressing effects on stock market returns after the crisis compared to before the crisis. Likewise, the results reveal that average stock market returns were significantly higher after the crisis compared to before the crisis at low rather than medium or high values of the two measures of inflation rate. These results suggest that the Kenyan stock market is highly sensitive to variations in inflation rate, especially as it emerges from a financial or political turmoil. This study is empirically innovative in the sense that it is the first to examine the moderating effect of the 2008 GFC on the relation between inflation rate and stock market returns in Kenya using a product-term model
Quantifying engineered nanomaterial toxicity: comparison of common cytotoxicity and gene expression measurements
BACKGROUND: When evaluating the toxicity of engineered nanomaterials (ENMS) it is important to use multiple bioassays based on different mechanisms of action. In this regard we evaluated the use of gene expression and common cytotoxicity measurements using as test materials, two selected nanoparticles with known differences in toxicity, 5 nm mercaptoundecanoic acid (MUA)-capped InP and CdSe quantum dots (QDs). We tested the effects of these QDs at concentrations ranging from 0.5 to 160 µg/mL on cultured normal human bronchial epithelial (NHBE) cells using four common cytotoxicity assays: the dichlorofluorescein assay for reactive oxygen species (ROS), the lactate dehydrogenase assay for membrane viability (LDH), the mitochondrial dehydrogenase assay for mitochondrial function, and the Comet assay for DNA strand breaks. RESULTS: The cytotoxicity assays showed similar trends when exposed to nanoparticles for 24 h at 80 µg/mL with a threefold increase in ROS with exposure to CdSe QDs compared to an insignificant change in ROS levels after exposure to InP QDs, a twofold increase in the LDH necrosis assay in NHBE cells with exposure to CdSe QDs compared to a 50% decrease for InP QDs, a 60% decrease in the mitochondrial function assay upon exposure to CdSe QDs compared to a minimal increase in the case of InP and significant DNA strand breaks after exposure to CdSe QDs compared to no significant DNA strand breaks with InP. High-throughput quantitative real-time polymerase chain reaction (qRT-PCR) data for cells exposed for 6 h at a concentration of 80 µg/mL were consistent with the cytotoxicity assays showing major differences in DNA damage, DNA repair and mitochondrial function gene regulatory responses to the CdSe and InP QDs. The BRCA2, CYP1A1, CYP1B1, CDK1, SFN and VEGFA genes were observed to be upregulated specifically from increased CdSe exposure and suggests their possible utility as biomarkers for toxicity. CONCLUSIONS: This study can serve as a model for comparing traditional cytotoxicity assays and gene expression measurements and to determine candidate biomarkers for assessing the biocompatibility of ENMs.1R01GM84702-01 - National Institute of General Medical Science
Modeling of airblast propagation through an enclosed structure
The ability to model explosively formed shock waves propagating through a
structure is of particular interest to engineers concerned with structural responses to blasts.
Accurate peak pressure and impulse values are critical to understanding blast loads on
structures and predicting the resulting structural behavior, but are sometimes difficult to
determine analytically. Experiments are necessary to determine the true structural response,
but the experiments alone may not identify all the details involved in an explosive event that
may be important for design purposes. When tied to experiments, computational modeling of
explosive events can be an invaluable tool for an engineer. The most difficult part of modeling
structural response to a close-in explosive event is capturing the fluid-structure interaction of
the resulting flow of the detonation products. In this paper, we compare the results of
numerical simulations of an explosive experimental event in an enclosed structure, or “attic
space”, using two different computational codes, CTH and DYSMAS. Both adequately model
the explosive event in attic space when compared to the experiment. We also compare the two
codes’ ability to produce explosive-induced pressure-time histories in the free field. The
advantage of using a coupled code like DYSMAS is that structural response can be more
accurately captured than by using a hydrocode like CTH alone. The differences between the
two codes’ ability to model the event are analyzed and described as well as a general
description of the shock wave propagation in the attic space
A provisional UniGene clone set based on ESTs from Neurospora crassa
We have constructed a list of N. crassa cDNA clones for which partial sequences exist, toward the goal of maximizing the number of genes represented while avoiding redundancy. This effort employed GenBank sequences from the combined N. crassa EST projects at the University of New Mexico, the University of Oklahoma and Dartmouth College (27,557 ESTs; Nelson et al. 1997 Fungal Genet. Biol.21:348-363; Zhu et al. 2001 Genetics 157: 1057-1065). The current list, subject to ongoing revision, includes 2842 clones and is available at the web site of the Neurospora Genome Project (NGP) at the University of New Mexico (http://www.unm.edu/~ngp/), along with details of its construction. Each cDNA clone in the list represents a unique gene. We have also assembled a UniGene set of cDNA clones for that portion of the UniGene set that is represented in libraries constructed by the NGP at UNM. This UniGene library is comprised of 1786 clones distributed in 20 96-well dishes, and it is available through the Fungal Genetics Stock Center
Surgical implications and variability in the use of the flat epithelial atypia diagnosis on breast biopsy specimens.
OBJECTIVES: Flat epithelial atypia (FEA) is a relatively new diagnostic term with uncertain clinical significance for surgical management. Any implied risk of invasive breast cancer associated with FEA is contingent upon diagnostic reproducibility, yet little is known regarding its use.
MATERIALS AND METHODS: Pathologists in the Breast Pathology Study interpreted one of four 60-case test sets, one slide per case, constructed from 240 breast biopsy specimens. An electronic data form with standardized diagnostic categories was used; participants were instructed to indicate all diagnoses present. We assessed participants\u27 use of FEA as a diagnostic term within: 1) each test set; 2) 72 cases classified by reference as benign without FEA; and 3) six cases classified by reference as FEA. 115 pathologists participated, providing 6900 total independent assessments.
RESULTS: Notation of FEA ranged from 0% to 35% of the cases interpreted, with most pathologists noting FEA on 4 or more test cases. At least one participant noted FEA in 34 of the 72 benign non-FEA cases. For the 6 reference FEA cases, participant agreement with the case reference FEA diagnosis ranged from 17% to 52%; diagnoses noted by participating pathologists for these FEA cases included columnar cell hyperplasia, usual ductal hyperplasia, atypical lobular hyperplasia, and atypical ductal hyperplasia.
CONCLUSIONS: We observed wide variation in the diagnosis of FEA among U.S. pathologists. This suggests that perceptions of diagnostic criteria and any implied risk associated with FEA may also vary. Surgical excision following a core biopsy diagnosis of FEA should be reconsidered and studied further
Case-control study of lung cancer risk from residential radon exposure
Abstract-A study of lung cancer risk from residential radon exposure and its radioactive progeny was performed with 200 cases (58% male, 42% female) and 397 controls matched on age and sex, all from the same health maintenance organization. Emphasis was placed on accurate and extensive year-long dosimetry with etch-track detectors in conjunction with careful questioning about historic patterns of in-home mobility
Characteristics associated with requests by pathologists for second opinions on breast biopsies.
AIMS: Second opinions in pathology improve patient safety by reducing diagnostic errors, leading to more appropriate clinical treatment decisions. Little objective data are available regarding the factors triggering a request for second opinion despite second opinion consultations being part of the diagnostic system of pathology. Therefore we sought to assess breast biopsy cases and interpreting pathologists characteristics associated with second opinion requests.
METHODS: Collected pathologist surveys and their interpretations of 60 test set cases were used to explore the relationships between case characteristics, pathologist characteristics and case perceptions, and requests for second opinions. Data were evaluated by logistic regression and generalised estimating equations.
RESULTS: 115 pathologists provided 6900 assessments; pathologists requested second opinions on 70% (4827/6900) of their assessments 36% (1731/4827) of these would not have been required by policy. All associations between case characteristics and requesting second opinions were statistically significant, including diagnostic category, breast density, biopsy type, and number of diagnoses noted per case. Exclusive of institutional policies, pathologists wanted second opinions most frequently for atypia (66%) and least frequently for invasive cancer (20%). Second opinion rates were higher when the pathologist had lower assessment confidence, in cases with higher perceived difficulty, and cases with borderline diagnoses.
CONCLUSIONS: Pathologists request second opinions for challenging cases, particularly those with atypia, high breast density, core needle biopsies, or many co-existing diagnoses. Further studies should evaluate whether the case characteristics identified in this study could be used as clinical criteria to prompt system-level strategies for mandating second opinions
The single-sided pulsator CO Camelopardalis
Abstract CO Cam (TIC 160268882) is the second “single-sided pulsator” to be discovered. These are stars where one hemisphere pulsates with a significantly higher amplitude than the other side of the star. CO Cam is a binary star comprised of an Am δ Sct primary star with Teff = 7070 ± 150 K, and a spectroscopically undetected G main-sequence secondary star. The dominant pulsating side of the primary star is centred on the L1 point. We have modelled the spectral energy distribution combined with radial velocities, and independently the TESS light curve combined with radial velocities. Both of these give excellent agreement and robust system parameters for both stars. The δ Sct star is an oblique pulsator with at least four low radial overtone (probably) f modes with the pulsation axis coinciding with the tidal axis of the star, the line of apsides. Preliminary theoretical modelling indicates that the modes must produce much larger flux perturbations near the L1 point, although this is difficult to understand because the pulsating star does not come near to filling its Roche lobe. More detailed models of distorted pulsating stars should be developed. These newly discovered single-sided pulsators offer new opportunities for astrophysical inference from stars that are oblique pulsators in close binary stars
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