When rockets and space-bound vehicles are fired into space, they have to deal
with turbulence, winds and waves in the Earth's atmosphere. Different height
regimes cause different problems. In the lower regions (0 to 20 km altitude),
winds and turbulence are major issues, whereas above 50 km altitude, large
atmospheric waves have serious importance on safe passage. Similar issues arise
on re-entry. In this talk, I will discuss the ways in which these atmospheric
phenomena manifest themselves, and how they are best mitigated. One example of
particular significance will be the Space Shuttle Columbia disaster, for which I
consulted with NASA in respect to possible atmospheric influences. I will also
describe some of the instrumentation used to measure these phenomena.
Impacts of asteroid and comets constitute major geologic processes shaping the
surfaces and evolution of planetary bodies. Impacts produce deep transient
cavities, with excavation to deep crustal levels, fragmentation, and removal of
large rock volumes. Formation of complex craters involves high pressures and
temperatures resulting in intense deformation, fracturing and melting. Here, we
analyze the crater-forming impacts and their effects on the Earth´s climate,
environment and life-support systems, in relation to the Cretaceous/Paleogene
(K/Pg) boundary. The boundary represents one of the major extinction events in
the Phanerozoic, which affected about 75 % of species. It is marked by a clay
layer globally distributed that is characterized by anomalous contents of
iridium and platinum group elements, marking the occurrence of a large bolide
impact. Studies have examined the age, stratigraphic correlations and
composition of the boundary layer, establishing a genetic association to the
Chicxulub impact in the Yucatan peninsula in the Gulf of Mexico. The Chicxulub
crater is a ~200 km diameter structure with peak ring and multi-ring morphology.
Impact generated a transient cavity some 20-25 km deep resulting in intense
deformation and shaking, which is recorded in the breccias and debris flow
deposits in the Gulf of Mexico and Caribbean Sea area. Impact was on a shallow
carbonate platform and resulted in huge tsunamis and in injection of CO2 and
sulfur components into the atmosphere. Effects of impacts in the environment and
climate of the Earth have been intensely investigated, mainly in relation to the
mass extinction, where the affectation in the evolution patterns was profound
and long-lasting. Effects of the K/Pg impact on the ecosystems extended for a
long period of several millions of years. The disappearance of large numbers of
species including complete groups severely affected the biodiversity and
ecosystem composition in the marine and continental realms.
We discuss a partition function of 3d supersymmetric gauge
theories on the (p, -1) Lens space.
In 3d the partition function is directly used to check dualities though the normalization is not seriously treated, especially, the phase is usually
ignored. However, when we consider the partition function on the orbifold the partition function consists of the sum of factors labeled by holonomies
and their relative
phases become crucial. We stress that the known formula for the partition function is incorrect and some relative phase factors are needed to identify the partition functions of
dual theories.