220 research outputs found

    Absolutely Continuous Invariant measures for non-autonomous dynamical systems

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    We consider the non autonomous dynamical system {τn},\{\tau_{n}\}, where τn\tau_{n} is a continuous map XX,X\rightarrow X, and XX is a compact metric space. We assume that {τn}\{\tau_{n}\} converges uniformly to τ.\tau . The inheritance of chaotic properties as well as topological entropy by τ\tau from the sequence {τn}\{\tau_{n}\} has been studied in \cite{Can1, Can2, Li,Ste,Zhu}. In \cite{You} the generalization of SRB\ measures to non-autonomous systems has been considered. In this paper we study absolutely continuous invariant measures (acim) for non autonomous systems. After generalizing the Krylov-Bogoliubov Theorem \cite{KB} and Straube's Theorem \cite{Str} to the non autonomous setting, we prove that under certain conditions the limit map τ\tau of a non autonomous sequence of maps {τn}\{\tau_n\} with acims has an acim

    ACIMs for Non-Autonomous Discrete Time Dynamical Systems; A Generalization of Straube's Theorem

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    This Master's thesis provides sufficient conditions under which a Non-Autonomous Dynamical System has an absolutely continuous invariant measure. The main results of this work are an extension of the Krylov-Bogoliubov theorem and Straube's theorem, both of which provide existence conditions for invariant measures of single transformation dynamical systems, to a uniformly convergent sequence of transformations of a compact metric space, which we define to be a non-autonomous dynamical system

    A Web-based archive of systematic review data

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    Systematic reviews have become increasingly critical to informing healthcare policy; however, they remain a time-consuming and labor-intensive activity. The extraction of data from constituent studies comprises a significant portion of this effort, an activity which is often needlessly duplicated, such as when attempting to update a previously conducted review or in reviews of overlapping topics

    Continuous renal replacement therapy for two neonates with hyperammonemia

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    Objectives: This study aims to assess the feasibility of using hemofiltration for ammonia clearance in low body weight infants with an inborn error of metabolism. Design: A study of two cases. Setting: Quaternary pediatric hospital (Saint Louis Children's Hospital) NICU and PICU. Patients: Infants <6 months of age with an ICD-9 diagnosis of 270.6 (hyperammonemia). Interventions: Continuous renal replacement therapy (CRRT). Measurements and Main Results: We measure serum ammonia levels over time and the rate of ammonia clearance over time. Continuous renal replacement therapy was more effective than scavenger therapy alone (Ammonul™) for rapid removal of ammonia in low weight infants (as low as 2.5 kg). Conclusions: Continuous renal replacement therapy is technically feasible in low weight infants with severe hyperammonemia secondary to an inborn error of metabolism

    Additively Manufactured Graphitic Electrochemical Sensing Platforms

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    Additive manufacturing (AM)/3D printing technology provides a novel platform for the rapid prototyping of low cost 3D platforms. Herein, we report for the first time, the fabrication, characterisation (physicochemical and electrochemical) and application (electrochemical sensing) of bespoke nanographite (NG)-loaded (25 wt. %) AM printable (via fused deposition modelling) NG/PLA filaments. We have optimised and tailored a variety of NG-loaded filaments and their AM counterparts in order to achieve optimal printability and electrochemical behaviour. Two AM platforms, namely AM macroelectrodes (AMEs) and AM 3D honeycomb (macroporous) structures are benchmarked against a range of redox probes and the simultaneous detection of lead (II) and cadmium (II). This proof-of-concept demonstrates the impact that AM can have within the area of electroanalytical sensors

    Denial at the top table: status attributions and implications for marketing

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    Senior marketing management is seldom represented on the Board of Directors nowadays, reflecting a deteriorating status of the marketing profession. We examine some of the key reasons for marketing’s demise, and discuss how the status of marketing may be restored by demonstrating the value of marketing to the business community. We attribute marketing’s demise to several related key factors: narrow typecasting, marginalisation and limited involvement in product development, questionable marketing curricula, insensitivity toward environmental change, questionable professional standards and roles, and marketing’s apparent lack of accountability to CEOs. Each of these leads to failure to communicate, create, or deliver value within marketing. We argue that a continued inability to deal with marketing’s crisis of representation will further erode the status of the discipline both academically and professionally

    Characterization and modeling of the Haemophilus influenzae core and supragenomes based on the complete genomic sequences of Rd and 12 clinical nontypeable strains

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    The genomes of 9 non-typeable H. influenzae clinical isolates were sequenced and compared with a reference strain, allowing the characterisation and modelling of the core-and supra genomes of this organism

    Workplace Turbulence and Workforce Preparedness

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    The year 1973 marked a divide in the postwar economy.1 During the 25 years between 1948 and 1973, private sector productivity increased at an annual rate of 2.9%. Productivity improvement after 1973 fell way below this long-term trend, leveling off at about 0.6% a year until 1981 and rising to only 1.6% a year between 1981 and 1987. A similar pattern is reflected in the real wages of the workforce.2The conventional interpretation of this difference in the U.S. economy before and after 1973 is that it reflects the combined influence of the OPEC oil shock and the influx into the labor market of inexperienced workers born in the postwar baby boom, possibly reinforced by growth in regulatory costs.3 However, when the productivity data are analyzed in a growth accounting framework, these economic factors can only account for about two thirds of the productivity decline.4 What then explains the balance of the shortfall in productivity? Many analysts have pointed to the intangible effects on managers of increased economic uncertainty since 1973—growing business cautiousness, increased emphasis on short-term financial objectives, and inadequate entrepreneurial incentives.5 But economic change and uncertainty can also affect productivity through their impact on jobs and workers
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