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To study the impact of climate change on Godthab(Greenland), temperature and precipitation gathered from the Global Historical Climatology Network (GHCN) were analyzed for patterns within 1866-2011. Both temperature and precipitation have experienced an overall increase throughout the past 146 years. Precipitation, however, has experienced a declining trend since 1985. North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) indices showed strong correlations with average annual temperature (R = ?0.6) and smaller correlations with annual total precipitation (R = ?0.2). There are moderate correlations between temperature, precipitation, and Southern-Oscillation Index (SOI). The positive phases of Pacific-North American (PNA) led to increased winter and spring precipitation. The climate mode’s influential strength on Godthab’s temperature and precipitation, vary seasonally. In contrast with global average temperatures, Greenland has not experienced a continual warming trend since the 1950s; 30- and 10-year trends show a cooling period between 1965 and 1995. From 1866 to 2011, Godthab’s average annual temperature has increased by 1.9?C, and is anticipated to continue to warm in accordance with the global warming trend and the Arctic’s associated feedback mechanisms.
The application of Sobolev gradient methods for finding critical points of the Huxley and Fisher models is demonstrated. A comparison is given between the Euclidean, weighted and unweighted Sobolev gradients. Results are given for the one dimensional Huxley and Fisher models.
engineering is a preeminent field which aims to regenerate or repair the
functions of devastated or damaged organs or tissues due to some accident,
disease or age related degeneration. This field provides immense help in saving
lives of thousands of patients. Tissues or organs are engineered within the
patient’s body or in a laboratory, which is later implanted in the patient’s
body. The important challenges for tissue engineers are: appropriate nutrients
supply and optimum cell density with uniform distribution of cells in a final
construct. Mathematical modeling is the best tool in order to understand the
mechanism of cell proliferation and nutrient supply in a bioreactor.
Mathematical models not only help to analyze potentially useful results but
also enlighten the way of further research. In this work, a simple mathematical
model of diffusive nutrient transport and non-linear cell proliferation in a
bioreactor is developed. A cell seeded porous scaffold is kept in a bioreactor
with a fixed nutrient supply. We model the consumption and transport of
nutrients by reaction-diffusion equation and cell proliferation by Fisher
Kolmogorove equation. Nutrient delivery to the cell seeded scaffold is purely
due to diffusion. The model is solved numerically by commercial finite element
solver COMSOL. The results show that all types of constructs, if nutrient
supply depends on diffusion, will produce cell proliferated regions near nutrient
supply. The results are presented for uniform and non-uniform initial cell
seeding strategies. It is also observed that cell proliferation is insensitive
to the initial seeding strategy.