X-Raying the Dark Side of Venus - Scatter from Venus Magnetotail?

This work analyzes the X-ray, EUV and UV emission apparently coming from the Earth-facing (dark) side of Venus as observed with Hinode/XRT and SDO/AIA during a transit across the solar disk occurred in 2012. We have measured significant X-Ray, EUV and UV flux from Venus dark side. As a check we have also analyzed a Mercury transit across the solar disk, observed with Hinode/XRT in 2006. We have used the latest version of the Hinode/XRT Point Spread Function (PSF) to deconvolve Venus and Mercury X-ray images, in order to remove possible instrumental scattering. Even after deconvolution, the flux from Venus shadow remains significant while in the case of Mercury it becomes negligible. Since stray-light contamination affects the XRT Ti-poly filter data from the Venus transit in 2012, we performed the same analysis with XRT Al-mesh filter data, which is not affected by the light leak. Even the Al-mesh filter data show residual flux. We have also found significant EUV (304 A, 193 A, 335 A) and UV (1700 A) flux in Venus shadow, as measured with SDO/AIA. The EUV emission from Venus dark side is reduced when appropriate deconvolution methods are applied; the emission remains significant, however. The light curves of the average flux of the shadow in the X-ray, EUV, and UV bands appear different as Venus crosses the solar disk, but in any of them the flux is, at any time, approximately proportional to the average flux in a ring surrounding Venus, and therefore proportional to the average flux of the solar regions around Venus obscuring disk line of sight. The proportionality factor depends on the band. This phenomenon has no clear origin; we suggest it may be due to scatter occurring in the very long magnetotail of Venus.Comment: This paper has been accepted in The Astrophysical Journa

Kinematics and Fine Structure of An Unwinding Polar Jet Observed by SDO/AIA

We present an observational study of the kinematics and fine structure of an unwinding polar jet, with high temporal and spatial observations taken by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO) and the Solar Magnetic Activity Research Telescope (SMART). During the rising period, the shape of the jet resembled a cylinder with helical structures on the surface, while the mass of the jet was mainly distributed on the cylinder's shell. In the radial direction, the jet expanded successively at its western side. The radial expansion presented three distinct phases: the gradually expanding phase, the fast expanding phase, and the steady phase. Each phase lasted for about 12 minutes. The angular speed of the unwinding jet and the twist transferred into the outer corona during the eruption are estimated to be 11.1 \times 10{-3} rad/s (period = 564 s) and 1.17 to 2.55 turns (or 2.34 to 5.1{\pi}) respectively. On the other hand, by calculating the azimuthal component of the magnetic field in the jet and comparing the free energy stored in the non-potential magnetic field with the jet's total energy, we find that the non-potential magnetic field in the jet is enough to supply the energy for the ejection. These new observational results strongly support the scenario that the jets are driven by the magnetic twist, which is stored in the twisted closed field of a bipole, and released through magnetic reconnection between the bipole and its ambient open field

Ranch Management: Handling Drought

Data on a hypothetical, but typical, ranch in northcentral South Dakota and three different 10-year weather patterns were fed into a computer to find the best profit options a rancher can take during drought. A diversified land use program with small grain and alfalfa combined with a diversified livestock program was more profitable over a 10-year period than a specialized program with pasture and beef production. This was true under all weather conditions. Irrespective of the land use program it was profitable to reduce or eliminate the beef cow herd during periods of drought. There must be favorable price relationships to pay the above-normal forage costs to keep the cow herd through drought. In years of normal rainfall, this beef cow herd was maintained between 175 and 200 head. Supplementary hog activities were selected at their maximum allowable scale under all weather conditions. Greater amounts of capital borrowing were required to survive a drought when supplementary livestock activities were not permitted or when a specialized pasture production program was employed. Following a 3-year drought it took 2-3 years to recover an annual cash balance which was greater than zero. A drought of the severity assumed in this study (no crops or hay at all in the third year) resulted in $67,346 less profit over a 10-year period for a diversified crop and livestock program compared to a similar period with no drought. A polyperiod linear programming model was used to analyze the effect of the three management strategies: (1) a beef cow herd with crop and pasture production, (2) beef cows with crop and pasture production plus hogs and sheep as supplementary operations, and (3) beef cows with supplementary hog and sheep operations and all land in pasture production. The three weather conditions were (1) a 10-year period with no drought, (2) a 10-year period with drought in the first 3 years and (3) a 10-year period with drought in the fourth, fifth, and sixth years. Government assistance during drought was assumed to be available

Development of a Control System for Positioning the Centerbody in a Choked Inlet

Since the introduction of high bypass ratio turbofan engines, the noise problem from aircraft shifted primarily from jet noise to noise of turbomachine origin. The present dominant noise source is the inlet noise generated by the first compressor stage (or the fan). Acoustic liners to reduce this noise have met with only limited success since the noise reduction to cost ratio is quite low. There are also many technical problems with acoustic liners that are not completely solved. Another method is by means of the choked inlet. This device simply accelerates the air to sonic velocities in the opposite direction of the sound propagation and literally chok8s off the noise. It has been found that choking is acoustically effective and brings about large noise reductions of as much as 30 db* but creates numerous aerodynamic problems including large pressure loss, possible instabilities, etc. However, it has been observed experimentally (see footnote and also from recent tests at NASA-Langley by Dr. Lumsdaine) that some noise reduction can be obtained even when the inlet is operating subsonically. The pressure recovery is high, and instabilities are minimum. It should be noted that large noise reductions are really not necessary since this would be a form of “overkill , because the noise from other sources of the aircraft is usually about 10 to 20 dbs below the maximum noise level which comes from the inlet. Thus, the amount of inlet noise reduction required with the sonic inlet depends on the other noise sources from the aircraft, the. environmental conditions, and the flight conditions (takeoff or landing, gross weight, flap setting, etc.). This means that an automatic control system must be used so that the pilot. can preset the amount of noise reduction desired for the prescribed conditions; then the automatic control would maintain the aerodynamic and acoustic performance of the inlet. The purpose of this thesis is to design, analyze and test an automatic control system to fulfill those requirements

Large amplitude oscillatory motion along a solar filament

Large amplitude oscillations of solar filaments is a phenomenon known for more than half a century. Recently, a new mode of oscillations, characterized by periodical plasma motions along the filament axis, was discovered. We analyze such an event, recorded on 23 January 2002 in Big Bear Solar Observatory H$\alpha$ filtergrams, in order to infer the triggering mechanism and the nature of the restoring force. Motion along the filament axis of a distinct buldge-like feature was traced, to quantify the kinematics of the oscillatory motion. The data were fitted by a damped sine function, to estimate the basic parameters of the oscillations. In order to identify the triggering mechanism, morphological changes in the vicinity of the filament were analyzed. The observed oscillations of the plasma along the filament was characterized by an initial displacement of 24 Mm, initial velocity amplitude of 51 km/s, period of 50 min, and damping time of 115 min. We interpret the trigger in terms of poloidal magnetic flux injection by magnetic reconnection at one of the filament legs. The restoring force is caused by the magnetic pressure gradient along the filament axis. The period of oscillations, derived from the linearized equation of motion (harmonic oscillator) can be expressed as $P=\pi\sqrt{2}L/v_{A\phi}\approx4.4L/v_{A\phi}$, where $v_{A\phi} =B_{\phi0}/\sqrt{\mu_0\rho}$ represents the Alfv\'en speed based on the equilibrium poloidal field $B_{\phi0}$. Combination of our measurements with some previous observations of the same kind of oscillations shows a good agreement with the proposed interpretation.Comment: Astron. Astrophys., 2007, in pres

An investigation into the relationship between PVA NWBA wheelchair basketball skills test and evaluative observations

The purpose of the study is to investigate the Paralyzed Veterans of America (PVA) National Wheelchair Basketball Association (NWBA) Wheelchair Basketball Skills Test. The purpose was to determine a comparable relationship between the PVA/NWBA Wheelchair Basketball Skills Test and the skill level judgment of the experts and novices ranking. The study examined the wheelchair basketball skills of 90 athletes who attended the PVA/NWBA National Basketball Camp in Springfield, Massachusetts in 1997. Of the 90 participants, 24 athletes (n=24) were observed by and ranked on a scale of high, average or low for their overall ability in the sport of wheelchair basketball. These rankings were compared to the rankings that each individual earned taking the PVA/NWBA Wheelchair Basketball Skills Test. The three: skills test, experts, and novice, rankings were then compared to the data. The results of the study indicated the experts agreed 70.8% of the time with the PVA/NWBA skills test and the novices agreed with the test 73.9%. Reliability coefficients were determined as .7427. The win/loss standings of the individual teams also were recorded and indicated that using the PVA/NWBA skills test to divide the athletes into equally competitive teams was an effective tool. From the results of the study the following conclusions were made: 1) the PVA/NWBA skills test was an adequate assessment to administer as an instrument describing basketball proficiencies of basketball athletes; 2) it was confirmed successful in evenly distributing the abilities of the athletes into equally competitive teams

Financial Analysis South Dakota Farm Panel Records Program 1975

The data in this report have been obtained from a selected number of farms located in Central South Dakota. It is a summary of data gained in a pilot program for the development of a computerized farm financial information system. For this reason the data in this report cannot be interpreted as representative of all farms or areas in South Dakota. However, it can serve as a guide to those persons with farm operations similar to the ones included in this report. Data is presented in this report on the average of all farms participating in the record keeping activities. It includes data for the high one third of the farms and the low one third of the farms. The high and the low are in terms of net farm income realized and not the high and low for each individual factor. Such data is useful to acquaint oneself with the range of results as well as the average

Financial Analysis South Dakota Farm Panel Records Program 1974

The data in this report have been obtained from a selected number of farms located in Central South Dakota. It is a summary of data gained in a pilot program for the development of a computerized farm financial information system. For this reason the data in this report cannot be interpreted as representative of all farms or areas in South Dakota. However, it can serve as a guide to those persons with farm operations similar to the ones included in this report. Data is presented in this report on the average of all farms participating in the record keeping activities. It includes data for the high one third of the farms and the low one third of the farms. The high and the low are in terms of net farm income realized and not the high and low for each individual factor. Such data is useful to acquaint oneself with the range of results as well as the average