7,120 research outputs found

    Maxeiner, Policy and Methods in German and American Antitrust Law: A Comparative Study

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    This thoughtful contribution to American and German legal literature provides valuable insights for a reader interested in comparing the decisionmaking methodology under the West German and American systems of antitrust law. The work also provides a broader discussion of key distinctions between the jurisprudential and systematic foundations of West Germany’s continental legal system and those of the Anglo-American common law system

    Elevated myc expression and c-myc amplification in spontaneously occurring B lymphoid cell lines

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    Recently, a minor subpopulation of murine B lymphocytes, Ly-1+ B cells, has been distinguished by its unique ontogeny, tissue distribution, and prominence in certain autoimmune and neoplastic B cell diseases. We have previously described a simple murine spleen culture system that results in the spontaneous and exclusive outgrowth of long-term Ly-1+ B cell lines (B Ly-1 cells). Here, we report that the immortal growth property of B Ly-1 cells correlates with a 10-45-fold elevation of steady-state myc RNA and 2-10-fold amplification of the c-myc locus. While c-myc amplification has been observed in malignant cell lines derived from several tissues of origin, its occurrence in lymphoid cells has not been previously reported. The consistent c-myc amplification in B Ly-1 cells may reflect a unique state of this locus in the Ly-1+ B lymphocyte lineage, and contribute to the spontaneous immortalization of this B cell population in vitro, and its apparent predilection for malignant transformation in vivo

    Approximation Limits of Linear Programs (Beyond Hierarchies)

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    We develop a framework for approximation limits of polynomial-size linear programs from lower bounds on the nonnegative ranks of suitably defined matrices. This framework yields unconditional impossibility results that are applicable to any linear program as opposed to only programs generated by hierarchies. Using our framework, we prove that O(n^{1/2-eps})-approximations for CLIQUE require linear programs of size 2^{n^\Omega(eps)}. (This lower bound applies to linear programs using a certain encoding of CLIQUE as a linear optimization problem.) Moreover, we establish a similar result for approximations of semidefinite programs by linear programs. Our main ingredient is a quantitative improvement of Razborov's rectangle corruption lemma for the high error regime, which gives strong lower bounds on the nonnegative rank of certain perturbations of the unique disjointness matrix.Comment: 23 pages, 2 figure

    Project Fireflies

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    Observational Window Functions in Planet Transit Surveys

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    The probability that an existing planetary transit is detectable in one's data is sensitively dependent upon the window function of the observations. We quantitatively characterize and provide visualizations of the dependence of this probability as a function of orbital period upon several observing strategy and astrophysical parameters, such as length of observing run, observing cadence, length of night, transit duration and depth, and the minimum number of sampled transits. The ability to detect a transit is directly related to the intrinsic noise of the observations. In our simulations of observational window functions, we explicitly address non-correlated (gaussian or white) noise and correlated (red) noise and discuss how these two noise components affect transit detectability in fundamentally different manners, especially for long periods and/or small transit depths. We furthermore discuss the consequence of competing effects on transit detectability, elaborate on measures of observing strategies, and examine the projected efficiency of different transit survey scenarios with respect to certain regions of parameter space.Comment: 16 pages, 11 figures, 8 tables; accepted for publication in Ap

    Expression of VPAC1 in a murine model of allergic asthma

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    Vasoactive intestinal polypeptide (VIP) is a putative neurotransmitter of the inhibitory non-adrenergic non-cholinergic nervous system and influences the mammalian airway function in various ways. Hence known for bronchodilatory, immunomodulatory and mucus secretion modulating effects by interacting with the VIP receptors VPAC1 and VPAC2, it is discussed to be a promising target for pharmaceutical intervention in common diseases such as COPD and bronchial asthma. Here we examined the expression and transcriptional regulation of VPAC1 in the lungs of allergic mice using an ovalbumin (OVA) -induced model of allergic asthma. Mice were sensitized to OVA and challenged with an OVA aerosol. In parallel a control group was sham sensitized with saline. VPAC1 expression was examined using RT-PCR and real time-PCR studies were performed to quantify gene transcription. VPAC1 mRNA expression was detected in all samples of OVA-sensitized and challenged animals and control tissues. Further realtime analysis did not show significant differences at the transcriptional level. Although the present studies did not indicate a major transcriptional regulation of VPAC1 in states of allergic airway inflammation, immunomodulatory effects of VPAC1 might still be present due to regulations at the translational level

    Teaching Sustainability Analysis in Electronics Lecture Courses

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    Based on positive prior experiences teaching sustainability analysis in electronics laboratory courses, this work explores techniques for teaching sustainability analysis in lecture courses. As difficult as it may seem to incorporate sustainability into integrated circuit courses or other engineering courses, it may prove as easy as asking students to consider how the coursework relates to sustainability issues. The need to educate students “to design a system, component, or process to meet desired needs within realistic constraints such as economic, environmental, social, political, ethical, health and safety, manufacturability, and sustainability” has gained sufficient value to deserve its own ABET Program Outcome, Criterion 3(c). This work presents a strategy to introduce students to the relevant issues before senior design coursework, thereby providing practice and enabling them to achieve such a program outcome more skillfully in senior level classes. Key practical challenges arise when attempting to add learning content to a one-quarter electronics course already bursting at the seams with conceptually challenging learning outcomes: 1. No extra class time exists in which to insert additional in-class activities; and 2. Few instructors desire the increased workload associated with reading dozens of additional student essays on top of normal assignment grading. To address the in-class time limitation, this work delivers the sustainability issues content online. To minimize excess faculty workload, this work presents a tool designed to assist faculty to use peer review of writing assignments, even in medium to large courses. Assessment data confirm the students assimilate new sustainability analysis skills

    A Paramedic Method Drill Master to Improve Student Writing

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    Engineering instructors have students write reports in order to help learn difficult concepts, data analysis, challenging problem solving, communication skills, and critical thinking. Sadly, many students seem to prefer obfuscating the subject matter and key ideas by using painfully unclear writing. An instructor dismayed by poor prose in submitted assignments has numerous familiar options available. Consider just a few: 1. Ignore the poor writing 2. Mark every error directly 3. Mark every error with a marginal comment 4. Give general feedback about the poor writing over the entire assignment 5. Expect students to rewrite and resubmit work 6. Change careers or retire Instructors who use one or more of the above techniques in response to their students’ work may or may not see their efforts bear fruit, but they do invest time in the process, sometimes quite significant amounts of time. This work questions whether a minor intervention could guide students without adding an excessive burden on the instructor. We describe a tool for students may use to help them identify poor writing symptoms and encourage targeted editing to improve clarity. In practice, it permits students to receive automated feedback prior to first submitting their work, freeing the instructor to focus on more interesting learning. Richard Lanham’s Paramedic Method, described wonderfully in his book, Revising Prose (Fifth Edition, Pearson Longman, 2007) inspired the author to steer students toward his excellent advice. However, in the author’s hands, the advice too often falls flat. Since devising this Paramedic Method Highlighter tool, the students seem to respond more positively and, sometimes, even edit their work. The webpage, http://tinyurl.com/PM-Macro, contains the free tool, instructions for its use, and video explanations. This work describes the tool, shows how instructors use it in class, gives student feedback, and assesses student work
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