Isolation and component structure in spaces of composition operators

We establish a condition that guarantees isolation in the space of composition operators acting between H p (B N ) and H q (B N ), for 0 \u3c p ≤ ∞, 0 \u3c q \u3c ∞, and N ≥ 1. This result will allow us, in certain cases where 0 \u3c q \u3c p ≤ ∞, completely to characterize the component structure of this space of operators

Economic analysis of shale gas wells in the United States

Thesis (S.B.)--Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 65-66).Natural gas produced from shale formations has increased dramatically in the past decade and has altered the oil and gas industry greatly. The use of horizontal drilling and hydraulic fracturing has enabled the production of a natural gas resource that was previously unrecoverable. Estimates of the size of the resource indicate that shale gas has the potential to supply decades of domestically produced natural gas. Yet there are challenges surrounding the production of shale gas that have not yet been solved. The economic viability of the shale gas resources has recently come into question. This study uses a discounted cash flow economic model to evaluate the breakeven price of natural gas wells drilled in 7 major U.S. shale formations from 2005 to 2012. The breakeven price is the wellhead gas price that produces a 10% internal rate of return. The results of the economic analysis break down the breakeven gas price by year and shale play, along with P20 and P80 gas prices to illustrate the variability present. Derived vintage supply curves illustrate the volume of natural gas that was produced economically for a range of breakeven prices. Historic Natural Gas Futures Prices are used as a metric to determine the volumes and percentage of total yearly production that was produced at or below the Futures Price of each vintage year. From 2005 to 2008, the total production of shale gas resulted in a net profit for operators. A drop in price in 2009 resulted in a net loss for producers from 2009 to 2012. In 2012, only 26.5% of the total gas volume produced was produced at or below the 2012 Natural Gas Futures Price.by Christopher D. Hammond.S.B

Parallel software tools at Langley Research Center

This document gives a brief overview of parallel software tools available on the Intel iPSC/860 parallel computer at Langley Research Center. It is intended to provide a source of information that is somewhat more concise than vendor-supplied material on the purpose and use of various tools. Each of the chapters on tools is organized in a similar manner covering an overview of the functionality, access information, how to effectively use the tool, observations about the tool and how it compares to similar software, known problems or shortfalls with the software, and reference documentation. It is primarily intended for users of the iPSC/860 at Langley Research Center and is appropriate for both the experienced and novice user

ニホン ノ ダイガク ニ オケル カイガイ ケンシュウ ウケイレ ニ カンスル イチコウサツ : コンゴ ジュウネンカン デノ コウキ ト トリクミ ノ カダイ

国内市場からの入学者数減少により、多くの日本の大学は深刻な財政上の困難に直面しており、さらには今後１０年間でより一層の悪化が予想されている。この問題に対する一つの考えうる解決策は、日本人学生数の減少を外国人学生の増大によって相殺し、延いては学問の国際的中枢機関として日本の大学のイメージを再構築することである。アメリカ合衆国のアブラハム・リンカーン留学奨学金プログラム検討委員会(the Abraham Lincoln Commission for Study Abroad)の創設目的は、２０１７年までにアメリカ人の年当りでの海外研修参加者数を４倍にすることであるが、これは日本に対してアメリカ人学生を惹き寄せる新たな好機を提供することになる。こうした好機に対応するために新たなチャレンジを伴うが、特に、不十分な日本語能力しか有せずに日本での修学を希望する多くのアメリカ人学生に対応するためには適切な対応手段を見出す必要がある。本論文は、近年日本の大学を悩ます入学者数問題を概観し、さらにはアメリカの高等教育におけるアブラハム・リンカーン留学奨学金プログラム検討委員会の目的を紹介することにある。そのうえで、日米にとって互恵的なものとなりうる、両国間での海外研修のための新たな提携関係をいかに創り出すかについて示すこととする。最後に、東京大学のケーススタディを用いて、英語による短期海外研修プログラムの創出、およびそれに付随して日本の大学が必要となる、英語能力のある教員、国際教育の専門家、および補助スタッフの雇用増大について論じる

Finding parallel functional pearls : automatic parallel recursion scheme detection in Haskell functions via anti-unification

This work has been partially supported by the EU H2020 grant “RePhrase: Refactoring Parallel Heterogeneous Resource-Aware Applications–a Software Engineering Approach” (ICT-644235), by COST Action IC1202 (TACLe), supported by COST (European Cooperation in Science and Technology) , by EPSRC grant “Discovery: Pattern Discovery and Program Shaping for Manycore Systems” (EP/P020631/1), and by Scottish Enterprise PS7305CA44.This paper describes a new technique for identifying potentially parallelisable code structures in functional programs. Higher-order functions enable simple and easily understood abstractions that can be used to implement a variety of common recursion schemes, such as maps and folds over traversable data structures. Many of these recursion schemes have natural parallel implementations in the form of algorithmic skeletons. This paper presents a technique that detects instances of potentially parallelisable recursion schemes in Haskell 98 functions. Unusually, we exploit anti-unification to expose these recursion schemes from source-level definitions whose structures match a recursion scheme, but which are not necessarily written directly in terms of maps, folds, etc. This allows us to automatically introduce parallelism, without requiring the programmer to structure their code a priori in terms of specific higher-order functions. We have implemented our approach in the Haskell refactoring tool, HaRe, and demonstrated its use on a range of common benchmarking examples. Using our technique, we show that recursion schemes can be easily detected, that parallel implementations can be easily introduced, and that we can achieve real parallel speedups (up to 23 . 79 × the sequential performance on 28 physical cores, or 32 . 93 × the sequential performance with hyper-threading enabled).PostprintPeer reviewe

Evidence That Pupil Size and Reactivity Are Determined More by Your Parents Than by Your Environment

Purpose: A classic twin study to evaluate the relative contributions of genetic and environmental factors to resting pupil size and reactivity. Methods: Pupillometry was performed on 326 female twins (mean age 64 years) from the TwinsUK Adult Twin Registry, assessing resting pupil diameter in darkness and increasing levels of ambient light, alongside dynamic pupillary characteristics. Maximum-likelihood structural equation models estimated the proportion of trait variance attributable to genetic factors. Results: Mean (SD) pupil diameter in darkness was 5.29 mm (0.81), decreasing to 3.24 mm (0.57) in bright light. Pupil light reaction (PLR) had a mean (SD) amplitude of 1.38 mm (0.27) and latency of 250.34 milliseconds (28.58). Pupil size and PLR were not associated with iris colour, intraocular pressure or refractive error, but were associated with age (diameter beta = -0.02, p = 0.016, constriction amplitude beta = -0.01, p < 0.001, velocity beta = 0.03, p < 0.001, and latency beta = 0.98, p < 0.001). In darkness the resting pupil size showed a MZ intraclass correlation coefficient of 0.85, almost double that of DZ (0.44), suggesting strong additive genetic effects, with the most parsimonious model estimating a heritability of 86% [95% confidence interval (CI) 79-90%] with 14% (95% CI 10-21%) explained by unique environmental factors. PLR amplitude, latency and constriction velocity had estimated heritabilities of 69% (95% CI 54-79%), 40% (95% CI 21-56%), and 64% (95% CI 48-75%), respectively. Conclusion: Genetic effects are key determinants of resting pupil size and reactivity. Future studies to identify these genetic factors could improve our understanding of variation in pupil size and pupillary reactions in health and disease

Genetic and Dietary Factors Influencing the Progression of Nuclear Cataract.

PURPOSE: To determine the heritability of nuclear cataract progression and to explore prospectively the effect of dietary micronutrients on the progression of nuclear cataract. DESIGN: Prospective cohort study. PARTICIPANTS: Cross-sectional nuclear cataract and dietary measurements were available for 2054 white female twins from the TwinsUK cohort. Follow-up cataract measurements were available for 324 of the twins (151 monozygotic and 173 dizygotic twins). METHODS: Nuclear cataract was measured using a quantitative measure of nuclear density obtained from digital Scheimpflug images. Dietary data were available from EPIC food frequency questionnaires. Heritability was modeled using maximum likelihood structural equation twin modeling. Association between nuclear cataract change and micronutrients was investigated using linear and multinomial regression analysis. The mean interval between baseline and follow-up examination was 9.4 years. MAIN OUTCOME MEASURES: Nuclear cataract progression. RESULTS: The best-fitting model estimated that the heritability of nuclear cataract progression was 35% (95% confidence interval [CI], 13-54), and individual environmental factors explained the remaining 65% (95% CI, 46-87) of variance. Dietary vitamin C was protective against both nuclear cataract at baseline and nuclear cataract progression (β = -0.0002, P = 0.01 and β = -0.001, P = 0.03, respectively), whereas manganese and intake of micronutrient supplements were protective against nuclear cataract at baseline only (β = -0.009, P = 0.03 and β = -0.03, P = 0.01, respectively). CONCLUSIONS: Genetic factors explained 35% of the variation in progression of nuclear cataract over a 10-year period. Environmental factors accounted for the remaining variance, and in particular, dietary vitamin C protected against cataract progression assessed approximately 10 years after baseline