5,231 research outputs found

    An Improved Point-Line Incidence Bound Over Arbitrary Fields

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    We prove a new upper bound for the number of incidences between points and lines in a plane over an arbitrary field F\mathbb{F}, a problem first considered by Bourgain, Katz and Tao. Specifically, we show that mm points and nn lines in F2\mathbb{F}^2, with m7/8<n<m8/7m^{7/8}<n<m^{8/7}, determine at most O(m11/15n11/15)O(m^{11/15}n^{11/15}) incidences (where, if F\mathbb{F} has positive characteristic pp, we assume m−2n13≪p15m^{-2}n^{13}\ll p^{15}). This improves on the previous best known bound, due to Jones. To obtain our bound, we first prove an optimal point-line incidence bound on Cartesian products, using a reduction to a point-plane incidence bound of Rudnev. We then cover most of the point set with Cartesian products, and we bound the incidences on each product separately, using the bound just mentioned. We give several applications, to sum-product-type problems, an expander problem of Bourgain, the distinct distance problem and Beck's theorem.Comment: 18 pages. To appear in the Bulletin of the London Mathematical Societ

    How a shortage of coins precipitated a depression in 15th century England

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    Wary that debtors wouldn't find coins to repay them, lenders rationed loans and created a credit crisis, writes Matthew Frank Steven

    In defense of the idea of differing conceptual schemes

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    Thesis (M.A.) -- University of Adelaide, Dept. of Philosophy, 198

    Some substituted 3-indoleacetic acids

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    Corn yield response to nitrogen and irrigation in southeast Missouri, 1963

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    Cover title."University of Missouri Agricultural Experiment Station and Farm Production Economics Division, Economic Research Service, U.S. Department of Agriculture cooperating."Includes bibliographical references

    Self-assembly of Tween 80 micelles as nanocargos for oregano and trans-cinnamaldehyde plant-derived compounds

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    The self-assembly of Tween 80 (T80) micelles loaded with plant-based oregano essential oil (OR) and trans-cinnamaldehyde (TCA) was studied. The effect of different factors, including the surfactant to oil ratio, the presence of sodium chloride, thermal treatment, and dilution on their formation and physicochemical stability was evaluated. The creation of nano-cargos was confirmed by TEM. The self-associated structures had z-average droplet diameters of 92 to 337 nm without any energy input. Whereas addition of 10% (w/v) NaCl prevented the formation of oregano essential oil nano-assemblies of T80, swollen micelles containing TCA were successfully produced. Moreover, the OR or TCA loaded-micelles had only a slight droplet size variation upon thermal treatment. Ultimately, their antibacterial activity analysis against some food pathogens revealed that the encapsulation of OR and TCA within micelles crucially improved their antibacterial activity. These straightforward and cost-effective designed systems can be applicable in different products, including foods and agrochemicals

    Office profile: Houston

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    A chemoselective and continuous synthesis of m-sulfamoylbenzamide analogues

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    For the synthesis of m-sulfamoylbenzamide analogues, small molecules which are known for their bioactivity, a chemoselective procedure has been developed starting from m-(chlorosulfonyl) benzoyl chloride. Although a chemoselective process in batch was already reported, a continuous-flow process reveals an increased selectivity at higher temperatures and without catalysts. In total, 15 analogues were synthesized, using similar conditions, with yields ranging between 65 and 99%. This is the first automated and chemoselective synthesis of m- sulfamoylbenzamide analogues

    Gender inequality and sex differences in physical fighting, physical activity, and injury among adolescents across 36 countries

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    Purpose: Sex differences in adolescent health are widely documented, but social explanations for these sex differences are scarce. This study examines whether societal gender inequality (i.e., men’s and women’s unequal share in political participation, decision-making power, economic participation and command over resources) relates to sex differences in adolescent physical fighting, physical activity, and injuries. Methods: National-level data on gender inequality (i.e. the United Nations Development Program’s Gender Inequality Index) were linked to health data from 71,255 15-year olds from 36 countries in the 2009/10 Health Behavior in School-aged Children (HBSC) study. Using multilevel logistic regression analyses, we tested the association between gender inequality and sex differences in health while controlling for country wealth (GDP per capita). Results: In all countries, boys reported more physical fighting, physical activity, and injuries than girls, but the magnitude of these sex differences varied greatly between countries. Societal gender inequality positively related to sex differences in all three outcomes. In more gender unequal countries, boys reported higher levels of fighting and physical activity, compared to boys in more gender equal countries. In girls, scores were consistently low for these outcomes, however injury was more common in countries with less gender inequality. Conclusions: Societal gender inequality appears to relate to sex differences in some adolescent health behaviors and may contribute to the establishment of sex differences in morbidity and mortality. To reduce inequalities in the health of future generations, public health policy should target social and cultural factors that shape perceived gender norms in young people

    Timed logic conformance and its application

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    Journal ArticleTimed Logic Conformance _x000B_TLC_x000C_ is a bisimulation-style partial order relationship defined over the statespace of Timed Safety Automata _x000B_TSA_x000C_ with real-valued clocks. In contrast to timed simulation. Calculus of Timed Refine- ment _x000B_CTR_x000C_, and Time-Abstracted bisimulation. TLC defines when one system is an acceptable implementation of another by asymmetric bisimulation-style requirements for specification inputs and implementation outputs. While TLC does not necessarily preserve timed properties, it intuitively and pragmatically supports writing abstract specifications and verifying them against implementations. TLC scales up by substituting verified specifications for implementations and hierarchically verifying larger systems. TLC verification is an alternative to assumes-guarantees reasoning process. TLC verification depends on explicitly capturing environmental timing properties in the specification and insuring they are satisfied in the TLC relation. The region-automata-based TLC System (_x000B_TLCS) implements TSA parallel composition and a TLC decision procedure which is used to hierarchically verify the STARI queue
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