Perturbations to observed ambient neutral densities due to presence of an Orbiting Geophysical Observatory

Perturbations in density of ions and neutral particles in upper atmosphere due to OG

The Fishes of Chadron Creek, Dawes County, Nebraska

This first modern comprehensive survey of fishes collected from Chadron Creek, Dawes County, Nebraska, documents collections made with a small seine and backpack electrofisher during November 2007 and February and March 2008. Chadron Creek’s fish community is of low diversity. The total of 3 collections at each of 9 stations along the length of Chadron Creek resulted in 254 individual fishes, which represented only 7 species within 4 families. Water quality parameters, including dissolved oxygen, pH, conductivity, total dissolved solids, temperature and fecal coliform counts indicate that Chadron Creek is a healthy stream capable of supporting a greater diversity of fishes. Land management practices may be responsible for elevated fecal coliform levels at one locality on the creek. Comparisons of fishes collected herein are made with historical records of fish collected between 1893 and 2000, and show that there are 50% fewer species present than those known from historical accounts

Schwarzschild-like black holes: Light-like trajectories and massless scalar absorption

Black holes are among the most intriguing objects in nature. They are believed to be fully described by General Relativity (GR), and the astrophysical black holes are expected to belong to the Kerr family, obeying the no-hair theorems. Alternative theories of gravity or parameterized deviations of GR allow black hole solutions, which have additional parameters other than mass and angular momentum. We analyze a Schwarzschild-like metric, proposed by Johannsen and Psaltis, characterized by its mass and a deformation parameter. We compute the absorption cross section of massless scalar waves for different values of this deformation parameter and compare it with the corresponding scalar absorption cross section of the Schwarzschild black hole. We also present analytical approximations for the absorption cross section in the high-frequency regime. We check the consistence of our results comparing the numerical and analytical approaches, finding excellent agreement.Comment: 8 pages, 14 figure

On Advanced Mobility Concepts for Intelligent Planetary Surface Exploration

Surface exploration by wheeled rovers on Earth's Moon (the two Lunokhods) and Mars (Nasa's Sojourner and the two MERs) have been followed since many years already very suc-cessfully, specifically concerning operations over long time. However, despite of this success, the explored surface area was very small, having in mind a total driving distance of about 8 km (Spirit) and 21 km (Opportunity) over 6 years of operation. Moreover, ESA will send its ExoMars rover in 2018 to Mars, and NASA its MSL rover probably this year. However, all these rovers are lacking sufficient on-board intelligence in order to overcome longer dis-tances, driving much faster and deciding autonomously on path planning for the best trajec-tory to follow. In order to increase the scientific output of a rover mission it seems very nec-essary to explore much larger surface areas reliably in much less time. This is the main driver for a robotics institute to combine mechatronics functionalities to develop an intelligent mo-bile wheeled rover with four or six wheels, and having specific kinematics and locomotion suspension depending on the operational terrain of the rover to operate. DLR's Robotics and Mechatronics Center has a long tradition in developing advanced components in the field of light-weight motion actuation, intelligent and soft manipulation and skilled hands and tools, perception and cognition, and in increasing the autonomy of any kind of mechatronic systems. The whole design is supported and is based upon detailed modeling, optimization, and simula-tion tasks. We have developed efficient software tools to simulate the rover driveability per-formance on various terrain characteristics such as soft sandy and hard rocky terrains as well as on inclined planes, where wheel and grouser geometry plays a dominant role. Moreover, rover optimization is performed to support the best engineering intuitions, that will optimize structural and geometric parameters, compare various kinematics suspension concepts, and make use of realistic cost functions like mass and consumed energy minimization, static sta-bility, and more. For self-localization and safe navigation through unknown terrain we make use of fast 3D stereo algorithms that were successfully used e.g. in unmanned air vehicle ap-plications and on terrestrial mobile systems. The advanced rover design approach is applica-ble for lunar as well as Martian surface exploration purposes. A first mobility concept ap-proach for a lunar vehicle will be presented

Implantación de las TIC en la materia química inorgánica

A lo largo de los años hemos observado el desinterés de los estudiantes en la materia de Química Inorgánica, perteneciente al curso de Ingeniería Química, la poca autonomía para estudiar y como consecuencia, un bajo rendimiento. Buscando contribuir a la solución de los problemas citados, propusimos la introducción de nuevas competencias utilizando las TIC en el currículo en el área de Ingeniería Química. Elegimos para el trabajo una metodología b-learning, con el uso de un entorno virtual de aprendizaje que fomente la participación colaborativa y el autoaprendizaje. Este trabajo presenta los resultados obtenidos con la experiencia mencionada.Throughout the years, we have noticed among students a lack of both interest and selfmotivation to study the subject of Inorganic Chemistry in the Chemical Engineering program, which, consequently, has resulted in student's poor performance. In an effort to find a solution to this problem, we proposed the implementation of Information and Communication Technology (ICT) skills into the curriculum. We chose a b-learning methodology, which utilizes an online virtual learning environment that encourages both collaborative participation and independent study. The following will discuss the results obtained from the aforementioned experiment

Paradeduction in Axiomatic Formal Systems

The concept of paradeduction is presented in order to justify that we can overlook contradictory information taking into account only what is consistent. Besides that, paradeduction is used to show that there is a way to transform any logic, introduced as an axiomatic formal system, into a paraconsistent one