519 research outputs found

    COVARIANCE ANALYSIS WITH A COVARIATE INTERACTION: AN EXAMPLE OF A SIMPLE LINEAR REGRESSION COMPARISON TECHNIQUE

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    Many real data sets that would normally lend themselves to being analyzed by an analysis of covariance, have a covariate interaction present with one or more of the factors in the experiment. Because this violates the assumption of same-slope covariate effect across all treatments, an analysis of covariance should not be performed. The course normally taken when there is such an interaction is to derive regression equations for the dependent variable as a function of the covariate, at each level of the factor(s) being tested. A general linear model F-test can then be used to test whether there are any overall differences between the regression lines. A technique that uses two mathematical distance measures to detect regression line differences once a significant general linear model F-test is obtained is illustrated. Applying these distance measures enables us to perform modified multiple comparisons of the regressions without resorting to the use of multiple pairwise general linear model F-tests, which inflate the Type I error rate. with this method, we are able to incorporate both factor and covariate information into the analysis to overcome the covariate-factor interaction problem

    Possible Subglacial Origin for Minor Moraine Topography

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    Surface expression of the Cary Age Drift (Des Moines lobe of Iowa) exhibits a pattern of intersecting linear ridges and depressions, known as swell-swale or minor moraine topography. Linear ridges, as mapped from air photos, are aligned either parallel or approximately transverse (45° to 90°) to associated end morainal systems. Both parallel and transverse ridges appear genetically related, range in height from 5-20 feet and are composed predominantly of till. Ridge intersections produce T , offset step and box patterns. The irregular shape and high dip of crossbedding of small sand bodies and the dip of small faults and joints suggest a controlled ice disintegration origin. Alignment of till fabric with glacier flow is indicative of a lodgment till or ground moraine. The current hypothesis that the minor moraines represent annual recessional moraines does not explain the lack of outwash, the origin of transverse ridges, till fabric, the number of moraines and their geographic distribution. Alternate hypotheses for the observed pattern are: 1) crevasse fill 2) ice marginal thrust 3) basal crevasse squeeze and 5) boundary wave phenomenon

    Effects of high fat diets on milk and fat production in commercial dairy herds

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    DISTANCE MEASURES IN POST HOC COMPARISONS OF TEMPERATURE GERMINATION QUADRATIC RESPONSE SURFACES

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    Generalized quadratic response surface models are used to describe seed germination at diurnally alternating cold and warm incubation temperatures for three Great Basin exotic plant species. The method of the F-statistic SSdrop is applied to determine whether the response surface models are equal. Two proposed distance measures are used as modified multiple comparison techniques for determining differences between surfaces. These measures prove useful in distinguishing between the species showing the highest germination response and the one showing the lowest response to the incubation temperature ranges studied

    Suppression of Mannheimia (Pasteurella) haemolytica serovar 1 infection in lambs by intrapulmonary administration of ovine antimicrobial anionic peptide

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    In this study, the efficacy of ovine antimicrobial anionic peptide (AP) was assessed in a lamb model of acute pneumonia. A single intratracheal dose of the peptide, H-DDDDDDD-OH (0.5 mg) reduced pulmonary inflammation and the concentration of Mannheimia (Pasteurella) haemolytica in infected lung tissue. Administration of H-DDDDDDD-OH after infection was more effective in reducing the consolidation and lesion scores at the deposition site than its administration prior to infection. Hence, the in vivo effectiveness of AP suggests that it may have applications in the treatment of pulmonary infections. Further studies are needed to confirm these findings and also to determine the optimal doses and intervals of H-DDDDDDD-OH therapy

    Graphical programming: A systems approach for telerobotic servicing of space assets

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    Satellite servicing is in many ways analogous to subsea robotic servicing in the late 1970's. A cost effective, reliable, telerobotic capability had to be demonstrated before the oil companies invested money in deep water robot serviceable production facilities. In the same sense, aeronautic engineers will not design satellites for telerobotic servicing until such a quantifiable capability has been demonstrated. New space servicing systems will be markedly different than existing space robot systems. Past space manipulator systems, including the Space Shuttle's robot arm, have used master/slave technologies with poor fidelity, slow operating speeds and most importantly, in-orbit human operators. In contrast, new systems will be capable of precision operations, conducted at higher rates of speed, and be commanded via ground-control communication links. Challenge presented by this environment include achieving a mandated level of robustness and dependability, radiation hardening, minimum weight and power consumption, and a system which accommodates the inherent communication delay between the ground station and the satellite. There is also a need for a user interface which is easy to use, ensures collision free motions, and is capable of adjusting to an unknown workcell (for repair operations the condition of the satellite may not be known in advance). This paper describes the novel technologies required to deliver such a capability

    Large thermoelectric figure of merit at high temperature in Czochralski-grown clathrate Ba8Ga16Ge30

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    The Czochralski method was used to grow a 46-mm-long crystal of the Ba8Ga16Ge30 clathrate, which was cut into disks that were evaluated for thermoelectric performance. The Seebeck coefficient and electrical and thermal conductivities all showed evidence of a transition from extrinsic to intrinsic behavior in the range of 600–900 K. The corresponding figure of merit (ZT) was found to be a record high of 1.35 at 900 K and with an extrapolated maximum of 1.63 at 1100 K. This makes the Ba8Ga16Ge30 clathrate an exceptionally strong candidate for medium and high-temperature thermoelectric applications

    Contracting Agile Developments for Mission Critical Systems in the Public Sector

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    Although Agile is a well established software development paradigm, major concerns arise when it comes to contracting issues between a software consumer and a software producer. How to contractualize the Agile production of software, especially for security & mission critical organizations, which typically outsource software projects, has been a major concern since the beginning of the \u201cAgile Era.\u201d In literature, little has been done, from a foundational point of view regarding the formalization of such contracts. Indeed, when the development is outsourced, the management of the contractual life is non\u2013trivial. This happens because the interests of the two parties are typically not aligned. In these situations, software houses strive for the minimization of the effort, while the customer commonly expects high quality artifacts. This structural asymmetry can hardly be overcome with traditional \u201cWaterfall\u201d contracts. In this work, we propose a foundational approach to the Law & Economics of Agile contracts. Moreover, we explore the key elements of the Italian procurement law and outline a suitable solution to merge some basic legal constraints with Agile requirements. Finally, a case study is presented, describing how Agile contracting has been concretely implemented in the Italian Defense Acquisition Process. This work is intended to be a framework for Agile contracts for the Italian public sector of critical systems, according to the new contractual law (Codice degli Appalti)
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