The Bare Theory Has No Clothes

We criticize the bare theory of quantum mechanics -- a theory on which the Schrödinger equation is universally valid, and standard way of thinking about superpositions is correct

Characterizing quantum theory in terms of information-theoretic constraints

We show that three fundamental information-theoretic constraints--the impossibility of superluminal information transfer between two physical systems by performing measurements on one of them, the impossibility of broadcasting the information contained in an unknown physical state, and the impossibility of unconditionally secure bit commitment--suffice to entail that the observables and state space of a physical theory are quantum-mechanical. We demonstrate the converse derivation in part, and consider the implications of alternative answers to a remaining open question about nonlocality and bit commitment.Comment: 25 pages, LaTe

Analysis of predictive sorting and process standardization at Amazon.com

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division; in conjunction with the Leaders for Global Operations Program at MIT, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 43-44).In any process, complexity has the potential to decrease processing rates of the operation. Mass production has driven up operator efficiency by removing complexity to create a standardized and simplified process. However, removing complexity from a process reduces the operator's ability to customize their products and remain flexible to variations in demand. Businesses need to decide the appropriate level of process standardization that allows their operators to work as efficiently as possible while remaining flexible enough to satisfy customer demand. The goal of this research is to analyze the standardization of the least efficient process in an outbound order fulfillment system at Amazon.com. Various tests were performed during a six-month internship at Amazon's Lexington, KY facility to determine if this process could benefit from standardization. The testing showed that Amazon's processes must maintain a high level of flexibility to satisfy the variations in customer demand and the diverse mix of products that they ship. This research ends with a proposed process improvement that will improve the efficiency of the baseline scenario while providing flexibility to handle variation in order flow. During the internship, the per-order cycle time at the packing operation has been reduced by 9.7% and another improvement was tested which reduced cycle times by 10.9% when implemented. When the final improvement is implemented the total cycle time reduction will be 20.6%.by Rob Jackson.S.M.M.B.A

Comparison of Driver Brake Reaction Times to Multimodal Rear-end Collision Warnings

This study examined the effectiveness of rear-end collision warnings presented in different sensory modalities as a function of warning timing in a driving simulator. Drivers experienced four warning conditions: no warning, visual, auditory, and tactile. The warnings activated when the time-to-collision (TTC) reached a critical value of 3.0 or 5.0 s TTC. Driver reaction time (RT) was captured from the time the driver crossed the warning activation threshold to brake initiation. Mean driver RT data showed that the tactile warning significantly outperformed the visual warning, providing support for tactile displays as effective rear-end collision warnings

Application of Sunlight Mapping in Solar Car Design

The design of a solar car is a combination of trade-offs between the mechanical, aerodynamic, and photovoltaic systems. The mechanical and aerodynamic systems can be computationally modeled very well using commercial software. Clouds prevent the photovoltaic system from being modeled as well. This research explores a new way to accurately simulate almost every array configuration imaginable. Using this method, quantitative simulations are produced

An Efficient and Accurate Approach for Studying the Heat Extraction from Multiple Recharge and Discharge Wells

In order to understand the thermal recovery Behavior of an engineered geothermal system (EGS), this paper develops a model in which fluid circulates in a single, planar hydraulic fracture with a constant hydraulic aperture via multiple recharging and discharging wells. The coupled equations for heat convection in the fracture plane and heat transfer into the rock are provided for steady and irrotational fluid flow conditions. By using velocity potentials and streamline functions, the temperature along a streamline is found to be only a function of the potential. By utilizing the Laplace transformation, the analytical solutions in the Laplace space for the temperature field are found, which are numerically inverted for time-domain results. Several examples with different arrangements of injection and production wells are investigated and the comparison with other published results is provided. The semi-analytical results demonstrate that the proposed model provides an efficient and accurate approach for predicting the temperatures of a multi-well reservoir system

'That is a Ministry of Health thing':Article 5.3 implementation in Uganda and the challenge of whole-of-government accountability

INTRODUCTION: While Uganda has made legislative progress towards implementing Article 5.3 of the WHO Framework Convention on Tobacco Control (FCTC), ongoing challenges in minimising tobacco industry interference have not been adequately explored. This analysis focuses on understanding difficulties in managing industry engagement across government ministries and in developing effective whole-of-government accountability for tobacco control. METHODS: Interviews with Uganda government officials within the health sector and beyond, including in Ministries of Trade, Agriculture and Revenue. RESULTS: The findings indicate substantial variations in awareness of Article 5.3, its norm and practices across government sectors. The data suggest ambiguity and uncertainty about accountability for Article 5.3 implementation, with policy makers in departments beyond health often uncertain about obligations under the FCTC. Second, we highlight how responsibility for Article 5.3 implementation and the obligations incurred are widely seen as restricted to the Ministry of Health. Third, competing mandates and perceived difficulties in reconciling health goals with economic growth are shown to impact on accountability for tobacco control. Yet, importantly, the data also demonstrate enthusiasm in some unexpected parts of government for actively engaging with Article 5.3 and for promoting greater intersectoral coordination. CONCLUSION: This paper demonstrates the intrinsic challenges of developing whole-of-government approaches, highlighting considerable uncertainty and ambiguity among decision makers in Uganda about tobacco control governance. The analysis points to the potential for Uganda’s national coordinating mechanism to help reconcile competing expectations and demonstrate the importance of Article 5.3 beyond health actors

Ribosomal RNA diversity predicts genome diversity in gut bacteria and their relatives

The mammalian gut is an attractive model for exploring the general question of how habitat impacts the evolution of gene content. Therefore, we have characterized the relationship between 16 S rRNA gene sequence similarity and overall levels of gene conservation in four groups of species: gut specialists and cosmopolitans, each of which can be divided into pathogens and non-pathogens. At short phylogenetic distances, specialist or cosmopolitan bacteria found in the gut share fewer genes than is typical for genomes that come from non-gut environments, but at longer phylogenetic distances gut bacteria are more similar to each other than are genomes at equivalent evolutionary distances from non-gut environments, suggesting a pattern of short-term specialization but long-term convergence. Moreover, this pattern is observed in both pathogens and non-pathogens, and can even be seen in the plasmids carried by gut bacteria. This observation is consistent with the finding that, despite considerable interpersonal variation in species content, there is surprising functional convergence in the microbiome of different humans. Finally, we observe that even within bacterial species or genera 16S rRNA divergence provides useful information about average conservation of gene content. The results described here should be useful for guiding strain selection to maximize novel gene discovery in large-scale genome sequencing projects, while the approach could be applied in studies seeking to understand the effects of habitat adaptation on genome evolution across other body habitats or environment types