Search for extrasolar planets with high-precision relative astrometry

We present our search program for substellar companions using high-precision relative astronomy. Due to its orbital motion around the star, an unseen substellar companion would produce a periodic "wobble" of the host star, which is the astrometric signal of the unseen companion. By measuring the separation between the components of stellar double and triple systems, we want to measure this astrometric signal of a possible unseen companion indirectly as a relative and periodic change of these separations. Using a new observation mode (the "cube-mode") where the frames were directly saved in cubes with nearly no loss of time during the readout, an adaptive optics system to correct for atmospheric noise and an infrared narrow band filter in the near infrared to suppress differential chromatic refraction (DCR) effects we achive for our first target (the double star HD 19994) a relative precision for the separation measurements of about 100...150 micro-arsecond per epoch. To reach a precision in the micro-arcsec-regime, we use a statistical approach. We take several thousand frames per target and epoche and after a verification of a Gaussian distribution the measurement precision can be calculated as the standard deviation of our measurements divided by the square root of the number of Gaussian distributed measurements. Our first observed target is the stellar binary HD 19994 A & B, where the A component has a known radial velocity planet candidate.Comment: 4 pages, IAUS 249 conferenc

Price effects of trading and components of the bid-ask spread on the Paris Bource

Time Series;Prices;Financial Markets;Supply and Demand

Geochemical evidence for incremental emplacement of Palms pluton, southern California

Indiana University-Purdue University Indianapolis (IUPUI)The objectives of this study are, generally, to analyze and understand internal processes that produce melts in an oceanic-continental subduction setting; and, specifically, to understand the assembly of a Cretaceous magmatic arc pluton (Palms pluton), including the timing of melt emplacement(s) and melt evolution from the source. SiO2 concentrations vary from ~ 69-76 % by weight. Whole rock trace element concentrations vary up to 7 times. Zircon analysis shows a minimum age difference in the pluton of 3 my, if considering the uncertainties of the oldest and youngest samples. According to the model made from the HEAT program, this is approximately six times longer than the estimated crystallization time of one batch of melt with the same physical properties as the Palms pluton. Two distinct sources, perceived from chemical analysis of premagmatic zircons, are found throughout the pluton. REE compositional patterns show a hybridization of Proterozoic and Mesozoic sources in some, but not all, Palms pluton granites. This data suggests that the pluton formed from multiple intrusions and the Proterozoic source remained relatively consistent throughout the pluton’s assembly with few additions of younger Mesozoic source material

Observed decadal variations of the zonal mean hygropause and its relationship to changes in the transport barrier

This study examines the long-term record of lower stratospheric water vapor focusing on the 20-year data record from the Stratospheric Aerosol and Gas Experiment II (SAGE II). The SAGE II zonal monthly mean water vapor data was enhanced to include the aerosol heavy late 1980s through the use of aerosol extinction filtering of the data. Comparisons between the SAGE II lower stratospheric water vapor and the Limb Infrared Monitor of the Stratosphere (LIMS), the Microwave Limb Sounder (MLS), and HALogen Occultation Experiment (HALOE) are performed. This study further focuses on the minimum lower stratospheric water vapor (i.e., hygropause) and on the dehydration seen in the hygropause with examination of the transport barrier at both the tropical tropopause and the tropopause folding region between the tropics and extra-tropics that would account for this decadal variation. The effects of aerosol contamination on the SAGE II water vapor retrievals from four volcanic eruptions from 1984 to 1992 were examined, leading to a four level filtering of the SAGE II water vapor data to allow retention of good data from early in the data record. With the improved filtered water vapor data, monthly and seasonal time series analyses show a significant decadal variation in the lower stratosphere for all months where the satellite coverage provided data from the late 1980s to the early 2000s. This decadal variation documents a decrease in the water vapor from below approximately 25 km to below the tropopause with this decrease seen in the hygropause from the tropics to the poles. Analysis of the hygropause for all months provided a statistically significant consistent neutral or decreasing value in the long-term water vapor minimum. March was shown to be the seasonal minimum in the hygropause over this 20-year low aerosol record, followed by a discontinuity in the minimum abundance after 2000. Three transport pathways for transport of water vapor from the moist troposphere to the lower stratosphere include the tropical tropopause, isentropic transport at the sub-tropical jet locations, and meridional transport from the tropics to the midlatitudes above the hygropause. The tropical tropopause temperatures were examined using the new Modern Era Retrospective-analysis for Research and Applications (MERRA) data set. Analysis showed a significant decrease in the tropical and sub-tropical tropopause temperatures over the 20-year timeframe for the DJF season preceding the March minimum. The lower temperatures would provide a colder "cold trap" at the tropopause, further "freeze drying" the air seasonally transported from the upper troposphere to the lower stratosphere, providing the long-term dehydration in the hygropause and lower stratosphere. The Ertel's Potential Vorticity (EPV or PV) was examined as a proxy for the sub-tropical jet movement towards the poles over this long-term record. Changes in this pathway location may affect the efficiency of isentropic transport of moist tropospheric air into the lower stratosphere at these higher latitudes. Analysis using the MERRA zonal EPV and maximum zonal Uwind data showed a statistically significant shift in the locations of the contours towards the SH poles over this 20-year timeframe for the DJF, DJFM seasons and the month of December. The meridional winds above the tropopause show an increase over the 20-year record covered by SAGE II water vapor data. These increasing winds are consistent with the increase in the Brewer-Dobson circulation shown in other studies. The colder tropopause temperatures along with the increasing Brewer-Dobson circulation just above the tropopause, are the likely cause for the decreasing water vapor trend as seen in the SAGE II March hygropause over the 20-years from 1986-2005.PhDCommittee Chair: Fu, Rong; Committee Member: Black, Robert; Committee Member: Doddridge, Bruce; Committee Member: Sokolik, Irina; Committee Member: Webster, Pete

Rainbow Trout (Salmo Gairdneri) Cage Culture and Primary Production In Eastern South Dakota Dugout Ponds

Rainbow trout (Salmo gairdneri) reared in 1 m³ cages in a South Dakota dugout pond grew and survived as well or better than most cage-cultured rainbow trout reported in the literature. Significant differences (P≤0.01) in mean length, weight, and food conversion, and similarity in relative weight between trout fed 2 and 4% of body weight daily, indicated that the optimum feeding rate was near 3% for this size range (35=100g). Daily rations based on fish size and water temperature need to be developed for trout reared in a lentic environment. The high cost of fingerlings was the limiting factor in a hypothetical dugout culture operation. Great water transparency seemed to be the major factor contributing to increased primary production, phytoplankton standing crop, and diel dissolved oxygen levels in comparisons between two unstocked dugout ponds. Suspension of sediments by wind actions may have been greater in the older pond because it was 18% larger in surface area but only 66% as deep as the never pond

Syllabus: How to Recover a Truly Sustainable Food System: A Look at Food Waste and Recovery

This course is an introduction to food waste, and the impact waste has on our food system. We will introduces the current food recovery hierarchy, and examines how consumers, producers and distributors waste food. We will explore the environmental and social impact of food waste in our food system, and introduce social and policy initiatives employed to recover food. Students will read, refect and discuss the actionable steps being taken to shift our local food system\u27s food waste into food recovery

Ownership and Control in the Netherlands

This paper analyses ownership and control structures of Dutch listed companies. Legislation effective since 1992 mandates all shareholders with holdings of 5 percent or more in Dutch companies to disclose their holdings. Our analysis shows that the average ownership stakes of the largest and the three largest shareholders are 27% and 41%, respectively. The average ownership stakes of banks, insurance companies and other financial institutions are relatively low. We observe that voting rights are more concentrated than ownership rights; the use of a supervisory board representing interests of different stakeholders is ubiquitous; and listed companies use different forms of antitakeover defence measures.Ownership, Control, Corporate governance