Temperature effects on Florida applesnail activity: implications for snail kite foraging success and distribution

The endangered Florida snail kite (Rostrhamlls sociaiJilis) feeds exclusively on applesnails (Pomacea pailiclosa), yet we lack direct observations that link applesnail behavior to snail kite foraging success. The purpose of our study was to evaluate the temperature-activity profile of applesnails in the context of restricted foraging opportunities for snail kites. Applesnail activity was monitored in water temperatures ranging from 2-2

Interactions between large space power systems and low-Earth-orbit plasmas

There is a growing tendency to plan space missions that will incorporate very large space power systems. These space power systems must function in the space plasma environment, which can impose operational limitations. As the power output increases, the operating voltage also must increase and this voltage, exposed at solar array interconnects, interacts with the local plasma. The implications of such interactions are considered. The available laboratory data for biased array segment tests are reviewed to demonstrate the basic interactions considered. A data set for a floating high voltage array test was used to generate approximate relationships for positive and negative current collection from plasmas. These relationships were applied to a hypothetical 100 kW power system operating in a 400 km, near equatorial orbit. It was found that discharges from the negative regions of the array are the most probable limiting factor in array operation

Rocks in Gettysburg College History

The glittering stones fill the cases in the lower lobby of the science center. Each one is has a tag saying where it was collected and what kind of rock formation it is. The cases themselves add to the feeling of being in a museum. Each rock is in pristine order and in good condition, very professional. While it is still not the most noticed of all collections on campus (located as it is on the bottom floor of the Science Center), it is still more obvious than it was just a few years ago. The rock collection is actually several different collections that have been put together over the past century and a half. The history of the mineral collection of Gettysburg College is intertwined with that of the Linnaean Society, John Gottlieb Morris, John J. Shank, and most recently Sarah Principato. Each of these parties is directly involved in the advancement of the mineralogical collection at Gettysburg College. [excerpt] Course Information: Course Title: HIST 300: Historical Method Academic Term: Spring 2006 Course Instructor: Dr. Michael J. Birkner \u2772 Hidden in Plain Sight is a collection of student papers on objects that are hidden in plain sight around the Gettysburg College campus. Topics range from the Glatfelter Hall gargoyles to the statue of Eisenhower and from historical markers to athletic accomplishments. You can download the paper in pdf format and click View Photo to see the image in greater detail.https://cupola.gettysburg.edu/hiddenpapers/1031/thumbnail.jp

The dominant X-ray wind in massive star binaries

We investigate which shocked wind is responsible for the majority of the X-ray emission in colliding wind binaries, an issue where there is some confusion in the literature, and which we show is more complicated than has been assumed. We find that where both winds rapidly cool (typically close binaries), the ratio of the wind speeds is often more important than the momentum ratio, because it controls the energy flux ratio, and the faster wind is generally the dominant emitter. When both winds are largely adiabatic (typically long-period binaries), the slower and denser wind will cool faster and the stronger wind generally dominates the X-ray luminosity.Comment: 4 pages, 1 figure, accepted by A&A Letter

Measuring the adjusted monetary base in an era of financial change - commentary

Money supply

Determination of the extent of ion thruster efflux

In the studies of proposed electric propulsion missions one of the areas of concern is the possible contamination of spacecraft instruments and thermal control surfaces by exhaust particles from an ion thruster. Vacuum tank tests were conducted in ground facilities to determine the extent of this deposition by thruster exhaust particles, but the application of these results to long term space missions is questionable. The flight thermal data from the SERT II satellite, the only electric propulsion mission with an extensive thruster operational history, was reviewed specifically to see if there is any evidence of contamination that could be attributed to the 5860 hours of mercury bombardment ion thruster operation. This evaluation of the flight data shows that the only evidence of deposition occurred on the contamination experiment solar cells which are located at the edge of the thruster exhaust beam. There is no evidence of any deposition of ion thruster efflux on any other surface of the satellite

Computer and laboratory simulation of interactions between spacecraft surfaces and charged-particle environments

Cases where the charged-particle environment acts on the spacecraft (e.g., spacecraft charging phenomena) and cases where a system on the spacecraft causes the interaction (e.g., high voltage space power systems) are considered. Both categories were studied in ground simulation facilities to understand the processes involved and to measure the pertinent parameters. Computer simulations are based on the NASA Charging Analyzer Program (NASCAP) code. Analytical models are developed in this code and verified against the experimental data. Extrapolation from the small test samples to space conditions are made with this code. Typical results from laboratory and computer simulations are presented for both types of interactions. Extrapolations from these simulations to performance in space environments are discussed

Space environmental interactions with spacecraft surfaces

Environmental interactions are defined as the response of spacecraft surfaces to the charged-particle environment. These interactions are divided into two broad categories: spacecraft passive, in which the environment acts on the surfaces and spacecraft active, in which the spacecraft or a system on the spacecraft causes the interaction. The principal spacecraft passive interaction of concern is the spacecraft charging phenomenon. The spacecraft active category introduces the concept of interactions with the thermal plasma environment and Earth's magnetic fields, which are important at all altitudes and must be considered the designs of proposed large space structures and space power systems. The status of the spacecraft charging investigations is reviewed along with the spacecraft active interactions

The home market and the pattern of trade: round three

Does national market size matter for industrial structure? Round One (Krugman) answered in the affirmative: Home market effects matter. Round Two (Davis) refuted this, arguing that an assumption of convenience-transport costs only for the differentiated goods-conveniently obtained the result. In Round Three we relax another persistent assumption of convenience- two industry types differentiated only by the degree of scale economies-and find that market size reemerges as a relevant force in determining industrial structure.International trade ; Econometric models

Portable electrophoresis apparatus using minimum electrolyte

An electrophoresis unit for use in conducting electrophoretic analysis of specimens is described. The unit includes a sealable container in which a substrate mounted specimen is suspended in an electrolytic vapor. A heating unit is employed to heat a supply of electrolyte to produce the vapor. The substrate is suspended within the container by being attached between a pair of clips which also serve as electrodes to which a direct current power source may be connected