This thesis is concerned with the ontology, epistemology, and methodology of intuitions in philosophy. It consists of an introduction, Chapter 1, and three main parts. In the first part, Chapter 2, I defend an account of intuitions as appearance states according to which intuitions cannot be reduced to beliefs or belief-like states. I argue that an account of intuitions as appearance states can explain some crucial phenomena with respect to intuitions better than popular accounts in the current debate over the ontology of intuitions. The second part, Chapters 3 to 5, is a reply to Timothy Williamson's (2004, 2007) view on the epistemology and methodology of intuitions. The practice of appealing to the fact that we have an intuition as evidence from thought experiments has recently been criticised by experimental philosophers. Williamson argues that since thought experiments reliably lead to knowledge of the content of our intuition, we can avoid this criticism and the resulting sceptical threat by appealing to the content of the intuition. I agree that thought experiments usually lead to knowledge of the content of our intuition. However, I show that appealing to the fact that we have an intuition is a common and useful practice. I defend the view that for methodological reasons, we ought to appeal to the fact that we have an intuition as initial evidence from thought experiments. The third part, Chapter 6, is devoted to a paradigm method involving intuitions: the method of reflective equilibrium. Some philosophers have recently claimed that it is trivial and could even accommodate scepticism about the reliability of intuitions. I argue that reflective equilibrium is not compatible with such scepticism. While it is compatible with the view I defend in the second part of the thesis, more specific methodological claims have to be made.

Factorial designs have been widely used in many scientific and industrial settings, where it is important to distinguish "active'' or real factorial effects from "inactive" or noise factorial effects used to estimate residual or "error" terms. We propose a new approach to screen for active factorial effects from such experiments that utilizes the potential outcomes framework and is based on sequential posterior predictive model checks. One advantage of the proposed method lies in its ability to broaden the standard definition of active effects and to link their definition to the population of interest. Another important aspect of this approach is its conceptual connection to Fisherian randomization tests. As in the literature in design of experiments, the unreplicated case receives special attention and extensive simulation studies demonstrate the superiority of the proposed Bayesian approach over existing methods. The unreplicated case is also thoroughly explored. Extensions to three level and fractional factorial designs are discussed and illustrated using a classical seat belt example for the former and part of a stem-cell research collaborative project for the latter. / Statistics

<p>This dissertation is concerned with the relationships between experiments in literature, science, and politics in twentieth-century United States culture. I argue that the three can be considered together by understanding "experimentation" as a set of processes rather than a method, and highlighting the centrality of writing and reading to experiments in all three arenas. Drawing on scientist Ludwik Fleck's concept of "valuable experiments," I read specific experiments in each field in conversation with the others, highlighting the ways in which science and politics require aesthetic structures, the ways in which science and literature reconfigure politics, and the ways in which politics and literature can intervene in and reconfigure scientific practices. Ultimately, I try to develop a reading practice that can make visible the shared transformative capacities of science, literature, and radical politics.</p><p>In the course of three chapters, I analyze the formal and conceptual innovations of writers such as William Burroughs, Ralph Ellison, and Carson McCullers, who were intimately affected by the uses of experimental science in corrective institutional practice. In doing so, I develop a concept of "experimental literature" that is distinct from avant-garde literature and can account for the investments that these writers share with scientists such as Albert Hofmann, Albert Einstein, and Margaret Mead. I argue that experimental writers denature literary genres that depend on coherent subjects, transparent reality, and developmental progress in order to disrupt similar assumptions that underpin positivist science. By understanding valuable experimental science and writing as continuous challenges to standardized scientific knowledge, I show how these writers contribute to ongoing radical social projects of queer and black radical traditions--such as those of George Jackson and the Combahee River Collective--which are grounded in knowledge as an aesthetic and political practice.</p> / Dissertation

My dissertation discusses a mechanism that thwarts sniping and improves efficiency in ascending Internet auctions with fixed ending times, specifically eBay. The first research chapter proposes a design of the bidding mechanism and the second chapter tests the effectiveness of the mechanism in a controlled environment. In addition, it presents an innovative theoretical representation of the eBay bidding environment. The first chapter investigates theoretically whether sellers can improve their profits in eBay-like auctions via the implementation of bidder credits. The analysis predicts that providing a credit, similar to a coupon or discount, for early bidding can thwart sniping and increase seller profit. The paper formulates and analyzes a multi-stage auction model with independently and identically distributed private values, where bidders place proxy bids. I show that sniping can emerge as a Bayesian-Nash equilibrium strategy so long as late bids run the risk of not being successfully received by the auctioneer; extending the prior work of Ockenfels and Roth. This equilibrium is inefficient and yields the worst outcome for sellers. The proposed credit mechanism awards a single early bidder a reduction, equal to the value of the credit, in the final price if he wins the auction. The optimal credit satisfies two necessary conditions; first, it increases seller ex-ante profit and second, it incentivizes bidders to deviate from the sniping equilibrium. Relative to the surplus generated by the sniping equilibrium, implementing the credit increases seller surplus and improves welfare. The second chapter experimentally investigates the effectiveness of the credit mechanism. In particular, it compares bidding strategies, seller profit, and overall efficiency in auction environments similar to eBay with and without credit incentives. I observe a significant decline in the frequency of sniping when subjects have the opportunity to receive the credit. The credit also improves auction efficiency primary because subjects overbid in auctions with the credit regardless of which subject has the credit. A within-subjects design allows me to directly compare differences across treatments conditional on the subjects being snipers. Auctions with snipers yield significantly lower profits to sellers because non-sniping rivals are bidding less aggressively when competing against a sniper.

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Pest status of the rice stem-borers, Diopsis longicornis and D. apicalis was not well known in the Republic of Guinee. / In the present study, adult and immature populations of both species were monitored under various local cultural practices, i.e., planting methods (direct and transplanted), different planting dates and seasons (wet and dry). As previously observed in other West African countries, D. apicalis did occasional damage to rice in Guinee. However, contrary to findings elsewhere, D. longicornis was not an important pest of Guinean rice, infesting 4% of stems over the five seasons studied. / Regulators affecting population size and behaviour of D. longicornis were determined, focusing on factors controlling the fly's quiescent period in aggregation sites during the dry season, and the insect's movement to and from these refugia. Availability of cultivated and wild rice was found to interrupt or prevent quiescence of D. longicornis. Abiotic factors, (relative humidity, rainfall and photoperiod) influenced time of dispersal of D. longicornis.

In this work, snow data, collected at the Centre for Atmospheric Research Experiments (CARE) site during the winter of 2005/06 as part of the Canadian CALIPSO/CloudSat Validation Project (C3VP) were analyzed with various goals in mind: 1) investigate the effects of surface temperature and system depth on the snow fall velocity and particle size distribution, 2) find the variables that control the relationships between snow fall velocity and size (control variables), 3) retrieve the coefficient and the exponent in the power-law mass-size relations used in snow reflectivity, 4) estimate vertical air motion and 5) describe the shape of snowflakes that can be used in polarimetric studies of snow. It also includes considerable calibration work on the Hydrometeor Velocity and Shape Detector (HVSD); as well as sensitivity testing for radar calibration and Mie-scattering effect on snow density. / Snow events were classified into several categories according to the radar echo vertical extent (H), surface and echo top temperatures (T s, Tt), to find their effects on snow fall velocity and particle size distribution. Several case studies, including situations of strong turbulence, were also examined. / Simple and multiple correlation analyses between control variables and parameters of the power-law size-velocity relationship were carried out for 13 snow cases having a high R2 between their mean snowflakes fall velocity and the v-D fitted curve, in order to find the control variables of power-law v-D relations. Those cases were all characterized by single layered precipitation with different echo depth, surface and echo top temperatures. Results show that the exponent "b" in v-D power-law relationship has little effect on the variability of snow fall velocity; all control variables (T s, Tt, H) correlate much better to the coefficient "a" than to the exponent "b", leading to a snow fall velocity that can be simulated with a varying coefficient "a" and a fixed exponent "b" (v=aD0.15) with good accuracy. Coefficient "a" and exponent "b" for a generic snow v-D relationship were also examined. The results indicate that coefficient "a" of generic snow represents the most frequent coefficient "a" during the events, while the exponent "b" does not show any representative. / Retrieval of the coefficient "a" and exponent "b" in a power-law mass-size relation, which eventually affects the snow reflectivity, was conducted by minimizing the root mean square (RMS) of differences in reflectivity between Vertically pointing McGill X-band Radar (VertiX) and HVSD. Minima of reflectivity differences lay on a diagonal direction of a diagram of the coefficient "a" (x-axis) versus exponent "b" (y-axis). It is shown that as the system deepens, the slope gets less steep. In addition, coefficient and exponent for this mass-size relation change with time, and snow density derived from several combined snow events does not explain the average snow density of the period. / A method to retrieve vertical air motion with good accuracy using VertiX and HVSD is suggested. Several snow shape parameters and relations between the area ratio (Ar) and size of snowflakes (Ar-D relation) are investigated with snow dimensions defined in various ways. These Ar-D relations will be used as a guideline in snow density models.

Impact induced dynamic cracks are produced with a Split Hopkinson Pressure Bar (SHPB) apparatus in two rocks (Kuru granite and Flamboro limestone) with impact velocities ranging from 8 to 12 m/s. Impact bit (tungsten carbide) diameters range from 8mm to 15mm. Dye impregnation combined with UV imaging, CAT scans and Optical scans were employed to study the resulting crack patterns. The resulting damage is quantified in terms of radial crack density on impact surface, crater, crushed zone and crack density with depth. In both rocks &lsquo;total&rsquo; damage obtained is directly proportional (exponential) with bit diameter and impact velocity. The &lsquo;total&rsquo; damage in Kuru granite is found to be greater than Flamboro limestone at all impact velocities; however, the crushed zone in the latter is found to consistently greater than the former. 2D simulations of dynamic fractures with AUTODYN have also been carried out showing good qualitative agreement with experimental results.

In studies involving intercropping plant populations, the main interest is to locate the position of the maximum response or to study the response pattern. Such studies normally require many plant population levels. Thus, designs such as spacing systematic designs that minimise experimental land area are desired. Randomised block designs may not perform well as they allow few population levels which may not span the maximum or enable exploration of other features of the response surface. However, lack of complete randomisation in systematic designs may imply spatial variability (largescale and small-scale variations i.e. trend and spatial dependence) in observations. There is no correct statistical method laid out for data analysis from such designs. Given that spacing systematic designs are not well explored in literature, the main thrusts of this study are two fold; namely, to explore the use of spatial modelling techniques in analysing and modelling data from systematic designs, and to evaluate the efficiency of systematic designs used in intercropping experiments. Three classes of models for trend and error modelling are explored/introduced. These include spatial linear mixed models, semi-parametric mixed models and beta-hat models incorporating spatial variability. The reliability and precision of these methods are demonstrated. Relative efficiency of systematic designs to completely randomised design are evaluated. The analysis of data from systematic designs is shown be easily implemented. Measures of efficiency that include <pp directed measures (A and E criteria), D1 and DB efficiencies for regression parameters, and power are used. Systematic designs are shown to be efficient; on average 72% for A and E- efficiencies and 93% for D1 and DB efficiencies. Overall, these results suggest that systematic designs are suitable and reliable for intercropping plant population studies. / Thesis (M.Sc.) - University of Natal, Pietermaritzburg, 2002

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