1,221 research outputs found

    The identification of the Romanovs: Can we (finally) put the controversies to rest?

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    For much of the 20th century the fate of the last Imperial family of Russia, the Romanovs, was a mystery after their execution in 1918. In the mid 1970s the mass grave of the Romanov family (minus two of the children) was discovered and officially exhumed after the fall of the Soviet Union. Forensic DNA testing of the remains in the early 1990s was used to identify the family. Despite the overwhelming evidence for establishing the identity of the Romanov family, a small but vocal number of scientists have tried to raise doubt about the DNA testing during the late 1990s and early 2000s. With the discovery of the two missing Romanov children in 2007, there was an opportunity to re-analyze all of the evidence associated with the case which confirmed the initial DNA testing and brought finality to the mystery. This article will discuss the controversies associated with the Romanov identification and reflect upon the importance of the case to the field of forensic DNA typing over the last 20 years

    Weed Thresholds

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    Four distinct pest management strategies are generally recognized by specialists: avoidance, prevention, suppression, and eradication. Avoiding awed population may be possible under certain circumstances, such as using crop rotation to avoid a particular weed problem, or planting the crop aftermost weeds of a particular species have germinated. However, this strategy is very limited with weeds since almost all fields are infested with a potentially economically damaging level of weed seeds. Prevention, simply stated, means not allowing a weed population to become established in a field. This is a lofty goal because of the propensity of weed seeds to spread from place to place. However, prevention should be an underlying strategy with every grower and practiced when feasible as a general sanitation measure. Suppression is the strategy employed by essentially all growers in an effort to produce their crop while keeping weed populations below an economically damaging level. It is this strategy that should receive most attention with respect to choosing and placing into practice the tactics for carrying out the plan: Eradication has very limited usefulness to most growers, since it is practically impossible except on small, isolated weed infestations

    Impacts of a Standing Disaster Payment Program on U.S. Crop Insurance

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    This research investigates the potential effects of the standing disaster assistance program proposed in the Senate version of the 2008 Farm Bill. Results suggest no significant impact on producer crop insurance purchase decisions. Payments under the program should be expected to differ considerably across geographic regions and levels of diversification, with the program providing the greatest benefit to undiversified producers in more risky production regions (e.g., the Southern Plains).

    Impacts of the SURE Standing Disaster Assistance Program on Producer Risk Management and Crop Insurance Programs

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    This research investigates the potential effects of the row crop provisions of the standing disaster assistance program (SURE) in the 2008 Farm Bill. Results suggest little impact on producer crop insurance purchase decisions, though the program does seem to provide an incentive for mid-level coverage. Payments under the program should be expected to differ considerably across geographic regions and levels of diversification, with the program providing the greatest benefit to undiversified producers in more risky production regions.crop insurance, disaster assistance, Farm Bill, SURE, Agricultural and Food Policy, Farm Management, Risk and Uncertainty, Q12, Q18,

    3D printing dimensional calibration shape: Clebsch Cubic

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    3D printing and other layer manufacturing processes are challenged by dimensional accuracy. Several techniques are used to validate and calibrate dimensional accuracy through the complete building envelope. The validation process involves the growing and measuring of a shape with known parameters. The measured result is compared with the intended digital model. Processes with the risk of deformation after time or post processing may find this technique beneficial. We propose to use objects from algebraic geometry as test shapes. A cubic surface is given as the zero set of a 3rd degree polynomial with 3 variables. A class of cubics in real 3D space contains exactly 27 real lines. We provide a library for the computer algebra system Singular which, from 6 given points in the plane, constructs a cubic and the lines on it. A surface shape derived from a cubic offers simplicity to the dimensional comparison process, in that the straight lines and many other features can be analytically determined and easily measured using non-digital equipment. For example, the surface contains so-called Eckardt points, in each of which three of the lines intersect, and also other intersection points of pairs of lines. Distances between these intersection points can easily be measured, since the points are connected by straight lines. At all intersection points of lines, angles can be verified. Hence, many features distributed over the build volume are known analytically, and can be used for the validation process. Due to the thin shape geometry the material required to produce an algebraic surface is minimal. This paper is the first in a series that proposes the process chain to first define a cubic with a configuration of lines in a given print volume and then to develop the point cloud for the final manufacturing. Simple measuring techniques are recommended.Comment: 8 pages, 1 figure, 1 tabl

    Analyzing Farmer Participation Intentions and Enrollment Rates for the Average Crop Revenue Election (ACRE) Program

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    The 2008 Farm Bill created the Average Crop Revenue Election (ACRE) program as a new commodity support program. Using a multinomial logit model to analyze a mail survey administered before the ACRE sign-up deadline, we identify factors driving farmer intentions regarding ACRE participation. Using a two-limit Tobit model to analyze actual county-level ACRE enrollment rates, we assess the effect of similar factors on actual farmer decisions. Results suggest that primary crops, risk perceptions, risk aversion, and program complexity were important factors. Farmer beliefs and attitudes also played key roles and were evolving during the months before the ACRE deadline.

    Electrodeposition in microgravity: Ground-based experiments

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    Electrodeposition was studied at one-hundreth g and compared with bench studies at 1 g. The low gravity was achieved during KC-135 aircraft parobolic flights. Flow in a simple cobalt cell (1 M CoSO4) operating under typical commercial conditions (10 to 20 mA/sq cm and 1 V) was monitored with a Schlieren optical system. Natural convection was absent at one-hundreth g. Quantitative comparisons on a cobalt cell with shielded electrodes using interferometry were carried out. Fringe shift differences indicate greater semi-infinite linear diffusion at 1 g than at one-hundreth g for cobalt. Since a shielded electrode operates under diffusion controlled conditions, no differences between 1 g and one-hundreth g would be expected. Similar comparisons on a shielded electrode copper cell were inconclusive. Bench codeposition experiments using polystyrene neutral buoyancy particles coupled with a shielded electrode cobalt cell were begun. Tracking of 12 micron particles showed no measurable difference between thermal/Brownian motion when the cell was operational or nonoperational. Initial experiments on codeposition quality showed a strong dependence upon cathode surface preparation in a shielded electrode configuration

    The effect of the implementation of comprehensive planning and management by objectives on the bureaucratization of a school organization

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    This study investigated the relationship of the implementation of comprehensive planning and management by objectives to the bureaucratization of a school organization. It was hypothesized that there would be an increase in bureaucratization within a school system as comprehensive planning and management by objectives were implemented. The data were collected by reviewing official school documents for the 1972-1977 school years. The documents included the minutes of the Board of Education meetings, organizational charts and job descriptions, memoranda, written policies and procedures, planning session information, agenda of principals' and central staff meetings, minutes of principals' and central staff meetings, handbooks, and evaluation documents

    A response to “Likelihood ratio as weight of evidence: a closer look” by Lund and Iyer

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    Recently, Lund and Iyer (L&I) raised an argument regarding the use of likelihood ratios in court. In our view, their argument is based on a lack of understanding of the paradigm. L&I argue that the decision maker should not accept the expert’s likelihood ratio without further consideration. This is agreed by all parties. In normal practice, there is often considerable and proper exploration in court of the basis for any probabilistic statement. We conclude that L&I argue against a practice that does not exist and which no one advocates. Further we conclude that the most informative summary of evidential weight is the likelihood ratio. We state that this is the summary that should be presented to a court in every scientific assessment of evidential weight with supporting information about how it was constructed and on what it was based
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