409 research outputs found
Numerical treatment of the Filament Based Lamellipodium Model (FBLM)
We describe in this work the numerical treatment of the Filament Based
Lamellipodium Model (FBLM). The model itself is a two-phase two-dimensional
continuum model, describing the dynamics of two interacting families of locally
parallel F-actin filaments. It includes, among others, the bending stiffness of
the filaments, adhesion to the substrate, and the cross-links connecting the
two families. The numerical method proposed is a Finite Element Method (FEM)
developed specifically for the needs of these problem. It is comprised of
composite Lagrange-Hermite two dimensional elements defined over two
dimensional space. We present some elements of the FEM and emphasise in the
numerical treatment of the more complex terms. We also present novel numerical
simulations and compare to in-vitro experiments of moving cells
The Role of the Court in Shaping the Relationship of the Individual to the State--The Canadian Supreme Court
The Case Against Entrenchment of a Canadian Bill of Rights
A limited form of judicial review has always been a prominent feature of Canadian federalism. Immediately after confederation, Canadian Courts assumed the jurisdiction to declare a statute to be beyond the legislative competence of the enacting body.\u27 Until comparatively recently, Courts have also assumed that a totality of unrestricted legislative power resides in Parliament and the Provincial legislatures, i.e., as long as legislative jurisdiction exists, there is no limitation on the nature of legislation which may be passed
The Role of the Court in Shaping the Relationship of the Individual to the State--The Canadian Supreme Court
The effects of female labor force participation on obesity
This paper assesses whether a causal relationship exists between recent increases in female labor force participation and the increased prevalence of obesity amongst women. The expansions of the Earned Income Tax Credit (EITC) in the 1980s and 1990s have been established by prior literature as having generated variation in female labor supply, particularly amongst single mothers. Here, we use this plausibly exogenous variation in female labor supply to identify the effect of labor force participation on obesity status. We use data from the National Health Interview Survey (NHIS) and replicate labor supply effects of the EITC expansions found in previous literature. This validates employing a difference-in-differences estimation strategy in the NHIS data, as has been done in several other data sets. Depending on the specification, we find that increased labor force participation can account for at most 19% of the observed change in obesity prevalence over our sample period. Our preferred specification, however, suggests that there is no causal link between increased female labor force participation and increased obesity.Women - Employment ; Obesity ; Tax credits
The Effects of Female Labor Force Participation on Obesity
This paper assesses whether a causal relationship exists between recent increases in female labor force participation and the increased prevalence of obesity amongst women. The expansions of the Earned Income Tax Credit (EITC) in the 1980s and 1990s have been established by prior literature as having generated variation in female labor supply, particularly amongst single mothers. Here, we use this plausibly exogenous variation in female labor supply to identify the effect of labor force participation on obesity status. We use data from the National Health Interview Survey (NHIS) and replicate labor supply effects of the EITC expansions found in previous literature. This validates employing a difference-in-differences estimation strategy in the NHIS data, as has been done in several other data sets. Depending on the specification, we find that increased labor force participation can account for at most 19% of the observed change in obesity prevalence over our sample period. Our preferred specification, however, suggests that there is no causal link between increased female labor force participation and increased obesity.female labor force participation, obesity, earned income tax credit
Kinetic modelling of colonies of myxobacteria
A new kinetic model for the dynamics of myxobacteria colonies on flat surfaces is derived formally, and first analytical and numerical results are presented. The model is based on the assumption of hard binary collisions of two different types: alignment and reversal. We investigate two different versions: a) realistic rod-shaped bacteria and b) artificial circular shaped bacteria called Maxwellian myxos in reference to the similar simplification of the gas dynamics Boltzmann equation for Maxwellian molecules. The sum of the corresponding collision operators produces relaxation towards nematically aligned equilibria, i.e. two groups of bacteria polarized in opposite directions.
For the spatially homogeneous model a global existence and uniqueness result is proved as well as exponential decay to equilibrium for special initial conditions and for Maxwellian myxos. Only partial results are available for the rod-shaped case. These results are illustrated by numerical simulations, and a formal discussion of the macroscopic limit is presented
Genotoxicity of 3-nitrobenzanthrone and 3-aminobenzanthrone in Muta™Mouse and lung epithelial cells derived from Muta™Mouse
FE1 lung epithelial cells derived from Muta (TM) Mouse are a new model system to provide in vitro mutagenicity data with the potential to predict the outcome of an in vivo Muta (TM) Mouse test. 3-Nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen identified in diesel exhaust and urban air pollution. We investigated the mutagenicity and DNA binding of 3-NBA and its main metabolite 3-aminobenzanthrone (3-ABA) in vitro and in vivo in the Muta (TM) Mouse assay. Mice were treated with 3-NBA or 3-ABA (0, 2 or 5 mg/kg body weight/day) by gavage for 28 days and 28 days later lacZ mutant frequency (MF) was determined in liver, lung and bone marrow. For both compounds, dose-related increases in MF were seen in liver and bone marrow, but not in lung; mutagenic activity was similar to 2-fold lower for 3-ABA than for 3-NBA. With 3-NBA, highest DNA adduct levels (measured by P-32-post-labelling) were found in liver (similar to 230 adducts per 10(8) nucleotides) with levels 20- to 40-fold lower in bone marrow and lung. With 3-ABA, DNA adduct levels were again highest in the liver, but similar to 4-fold lower than for 3-NBA. FE1 cells were exposed to up to 10 mu g/ml 3-NBA or 3-ABA for 6 h with or without exogenous activation (S9) and harvested after 3 days. For 3-NBA, there was a dose-related increase in MF both with and without S9 mix, which was > 10 times higher than observed in vivo. At the highest concentration of 3-ABA (10 mu g/ml), we found only around a 2-fold increase in MF relative to controls. DNA adduct formation in FE1 cells was dose-dependent for both compounds, but 10- to 20-fold higher for 3-NBA compared to 3-ABA. Collectively, our data indicate that Muta (TM) Mouse FE1 cells are well suited for cost-effective testing of suspected mutagens with different metabolic activation pathways as a guide for subsequent in vivo Muta (TM) Mouse testing
Liquid chromatography—tandem mass spectrometry analysis of the DNA adducts of aristolochic acids
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