492 research outputs found
The Suspension of the Absolute Power of Alienation
In his Nature and Sources of Law, John Chipman Gray says, The Common Law has often been reproached with the lack of precision and certainty in its definitions, but, in truth, it is a great advantage of the Common Law, and of the mode of its development by judicial decision, that its definitions are never the matters resolved by the cases; they are never anything but dicta. If at the end of the sixteenth, or of the seventeenth, or even of the eighteenth century, there had been definitions binding by statute on the Courts; if the meaning of \u27contract\u27, and \u27malice\u27, and .\u27possession\u27, and \u27perpetuities\u27 had been fixed, what fetters would have been imposed on the natural development of the Law. And it is the great disadvantage of a code, that practising lawyers and jurists alike are hampered by the cast-iron classification and definitions of a former generation, which, in the advancement of legal thought and knowledge, are now felt to be imperfect and inadequate. \u27 Confining the illustration to the word \u27perpetuities\u27 the above quotation is so apt to the purpose of this article that it may well serve as a text for it
Model-Based Analysis for Qualitative Data: An Application in Drosophila Germline Stem Cell Regulation.
Discovery in developmental biology is often driven by intuition that relies on the integration of multiple types of data such as fluorescent images, phenotypes, and the outcomes of biochemical assays. Mathematical modeling helps elucidate the biological mechanisms at play as the networks become increasingly large and complex. However, the available data is frequently under-utilized due to incompatibility with quantitative model tuning techniques. This is the case for stem cell regulation mechanisms explored in the Drosophila germarium through fluorescent immunohistochemistry. To enable better integration of biological data with modeling in this and similar situations, we have developed a general parameter estimation process to quantitatively optimize models with qualitative data. The process employs a modified version of the Optimal Scaling method from social and behavioral sciences, and multi-objective optimization to evaluate the trade-off between fitting different datasets (e.g. wild type vs. mutant). Using only published imaging data in the germarium, we first evaluated support for a published intracellular regulatory network by considering alternative connections of the same regulatory players. Simply screening networks against wild type data identified hundreds of feasible alternatives. Of these, five parsimonious variants were found and compared by multi-objective analysis including mutant data and dynamic constraints. With these data, the current model is supported over the alternatives, but support for a biochemically observed feedback element is weak (i.e. these data do not measure the feedback effect well). When also comparing new hypothetical models, the available data do not discriminate. To begin addressing the limitations in data, we performed a model-based experiment design and provide recommendations for experiments to refine model parameters and discriminate increasingly complex hypotheses
NIRS Measurements with Elite Speed Skaters: Comparison Between the Ice Rink and the Laboratory
Wearable, wireless near-infrared (NIR) spectrometers were used to compare changes in on-ice short-track skating race simulations over 1,500 m with a 3-min cycle ergometry test at constant power output (400 W). The subjects were six male elite short-track speed skaters. Both protocols elicited a rapid desaturation (∆TSI%) in the muscle during early stages (initial 20 s); however, asymmetry between right and left legs was seen in ΔTSI% for the skating protocol, but not for cycling. Individual differences between skaters were present in both protocols. Notably, one individual who showed a relatively small TSI% change (-10.7%, group mean = -26.1%) showed a similarly small change during the cycling protocol (-5.8%, group mean = -14.3%). We conclude that NIRS-detected leg asymmetry is due to the specific demands of short-track speed skating. However, heterogeneity between individuals is not specific to the mode of exercise. Whether this is a result of genuine differences in physiology or a reflection of differences in the optical properties of the leg remains to be determined
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Everything you always wanted to know about dictionaries (but were afraid to ask): A Massive Open Online Course
© Lexicography in Global Contexts. We have created a Massive Open Online Course (MOOC) about dictionaries and dictionary-making, to be hosted by FutureLearn. This paper discusses the design and development of this course, which is pitched at high school and undergraduate level participants as well as language enthusiasts around the world. The MOOC will answer questions such as: how dictionaries are made and how this process has changed over time; what goes into a dictionary and who decides; and what kinds of language evidence underpin the information which dictionaries provide. Participants will be encouraged to compare the quantity and quality of information in different types of dictionary, and will investigate corpus-based and computational lexicographic methods. It will also consider dictionary users' attitudes and common misconceptions, taking into account the requirements and habits of English language learners as well as fluent speakers. By the end of the course, participants will know about some of the latest trends in lexicographic research, the roles of language technology, corpora and crowdsourcing in the dictionary compilation process, the range of possible dictionary entry components, lexicographical choices and computational methods surrounding the selection and ordering of word meanings, and the content and wording of definitions
Base-Controlled Diastereoselective Synthesis of Either anti- or syn-β-Aminonitriles
Deprotonation of secondary alkane nitriles with nBuLi and addition to aryl imines gives kinetic anti-β-aminonitriles. Use of LHMDS allows reversible protonation of the reaction intermediate to give syn-β-aminonitriles. The pure diastereosiomers can be isolated in good yields, and the mechanism was elucidated
Inverse spectral problems for Sturm-Liouville operators with singular potentials
The inverse spectral problem is solved for the class of Sturm-Liouville
operators with singular real-valued potentials from the space .
The potential is recovered via the eigenvalues and the corresponding norming
constants. The reconstruction algorithm is presented and its stability proved.
Also, the set of all possible spectral data is explicitly described and the
isospectral sets are characterized.Comment: Submitted to Inverse Problem
Reductive conjugate addition nitro-Mannich route for the stereoselective synthesis of 1,2,3,4-tetrahydroquinoxalines
A concise, high yielding and structurally divergent synthesis of complex 1,2,3,4-tetrahydroquinoxalines with excellent diastereoselectivity is described. A wide array of nitroalkenes and imines derived from commercially available aromatic aldehydes and 2-chloroanalines were subjected to a key reductive conjugate addition nitro-Mannich reaction to give diastereomerically pure β-nitro amines. Sequential reduction of the nitro function followed by Pd-catalyzed intramolecular N-arylation of the resultant primary amine onto the 2-chloroanailine gives highly substituted 1,2,3,4-tetrahydroquinoxalines. Non basic imines were found to participate better in the nitro-Mannich reaction if the stronger acid methanesulfonic acid was used to promote the reaction. The 3 step reaction sequence should be useful for the array synthesis of drug like scaffolds
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