1,792 research outputs found

    Changing preferences: an experiment and estimation of market-incentive effects on altruism

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    This paper studies how altruistic preferences are changed by markets and incentives. We conduct a laboratory experiment in a within-subject design. Subjects are asked to choose health care qualities for hypothetical patients in monopoly, duopoly, and quadropoly. Prices, costs, and patient benefits are experimental incentive parameters. In monopoly, subjects choose quality to tradeoff between profits and altruistic patient benefits. In duopoly and quadropoly, we model subjects playing a simultaneous-move game. Each subject is uncertain about an opponent's altruism, and competes for patients by choosing qualities. Bayes-Nash equilibria describe subjects' quality decisions as functions of altruism. Using a nonparametric method, we estimate the population altruism distributions from Bayes-Nash equilibrium qualities in different markets and incentive configurations. Markets tend to reduce altruism, although duopoly and quadropoly equilibrium qualities are much higher than those in monopoly. Although markets crowd out altruism, the disciplinary powers of market competition are stronger. Counterfactuals confirm markets change preferences.Accepted manuscrip

    Deagglomeration and mixing via the rapid expansion of high pressure and supercritical suspensions

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    Nano-materials are the focus of many research activities due to the desirable properties imparted from their small grain size and high interfacial surface area. However, these materials are highly cohesive powders in the dry state and typically form large agglomerates, leading to a diminished surface area or even grain growth, which minimizes the effectiveness of these nanomaterials. This dissertation addresses the issue of mixing nanopowders constituents by deagglomerating them and achieving simultaneous mixing so that even after inevitable reagglomeration, the effectiveness of large interfacial surface area may be preserved. Nano-particle mixtures were prepared using the environmentally benign dry mixing methods of Stirring in Supercritical Fluids and the Rapid Expansion of High Pressure and Supercritical Suspensions (REHPS). Stirring in Supercritical Fluids was capable of producing course scale nano-particle mixtures that were comparable to mixtures produced with more traditional liquid solvents, without the necessity of filtration and caking issues that are typically associated with them. The REHPS process was capable of producing high-quality mixtures on the sub-micron scale, and was made far superior when the nano-powders were first pre-mixed by stirring to decrease inhomogeneity of the feed. It was also shown that in general, conditions that enhanced turbulent shear stress, and thereby deagglomeration, also enhanced mixing, however this effect could be obscured by inhomogeneities introduced by the feed mixtures. Previous authors have suggested that the primary deagglomeration mechanism is the explosive expansion of the carbon dioxide from within the agglomerate as it transitions from a high pressure to an ambient environment. In this study two other deagglomeration mechanisms were proposed, namely intense turbulent shear stress imparted by the fluid in the nozzle and impaction with the Mach disc near the exit of the nozzle. Explosive expansion was observed to have almost no effect on nozzle deagglomeration and subsequent mixing. It has been shown that the turbulent shear stress and the residence time under shear were the dominant factors related to agglomerate breakage, while impaction with the Mach disc has played a minimal role

    Evaluation of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) for the Identification of Group B Streptococcus.

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    Objective Group B Streptococcus (GBS) is a leading cause of neonatal meningitis and sepsis worldwide. Intrapartum antibiotics given to women carrying GBS are an effective means of reducing disease in the first week of life. Rapid and reliable tests are needed to accurately identify GBS from these women for timely intrapartum antibiotic administration to prevent neonatal disease. Many laboratories now use matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) by direct plating or cell lysis for the identification of GBS isolates. The cell lysis step increases time to results for clinical samples and is more complex to perform. Therefore, we seek to evaluate the sensitivity and specificity of the quicker and more rapid direct plating method in identifying GBS. Results We directly compared swab isolates analysed by both direct plating and cell lysis method and demonstrated that direct plating has a sensitivity and specificity of 0.97 and 1, respectively, compared to an additional cell lysis step. We demonstrated that MALDI-TOF MS can be successfully used for batch processing by the direct plating method which saves time. These results are reassuring for laboratories worldwide who seek to identify GBS from swabs samples as quickly as possible

    Radioactive Contamination at Dayton Canyon from the Santa Susana Filed Laboratory

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    Radioactive Contamination at Dayton Canyon from the Santa Susana Filed Laboratory was a report that was deeply flawed as the result of the Department of Toxic Substances Control (DTSC) misrepresenting the underlying data , as well as poor protection levels and an a priori assumption that there can\u27t be contamination coming from Santa Susana Field Laboratory (SSFL). It should be rejected. Correspondence and context for this failed study, and the ways the Committee to Bridge the Gap and its researchers were led astray by aforementioned parties, is documented in detail here. This research was completed money allocated during Round 6 of the Citizens’ Monitoring and Technical Assessment Fund (MTA Fund). Clark University was named conservator of these works. If you have any questions or concerns please contact us at [email protected]://commons.clarku.edu/bridge_gap/1002/thumbnail.jp

    Radioactive Contamination at Runkle Ranch from the Santa Susana Field Laboratory

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    Runkle Ranch is the site of a proposed residential development in Simi Valley. Because it is located near to, and below, the Santa Susana Field Laboratory ((SFL), a nuclear reactor and rocket testing and development facility with significant radioactive and chemical contamination, the developer arranged for a series of tests of soil and other environmental media. SSFL is operated for the U.S. government by the Rocketdyne Division of the Boeing Company. This report examines the results of the soil testing for radioactivity. The Environmental Impact Report (EIR) that supported the approval of the project briefly addressed the potential for contaminants from SSFL to have impacted the Runkle Ranch land and concluded that this was not an issue. The EIR1 noted that background levels of strontium-90 are “about 0.1 pico Curie per gram (pCi/g)” and went on to describe sampling results for the Runkle property: Previous assessments of strontium-90 and tritium within the vicinity of the [Runkle Canyon] Specific Plan Area included a survey conducted by QST Environmental, Inc. in 1998. This study was conducted to determine if nuclear 1 This and the following two quotes are from pp. 4.6-6 and 4.6-7 of the EIR. 2 reactor operations at the SSFL facility had impacted soil at the site through surface water runoff. Four soil samples at three were collected and analyzed for cesium-137, strontium-90 and tritium. One of the locations was within a natural drainage channel flowing from the locale of the SSFL facility towards the northeastern portion of the Specific Plan Area. The results of the survey indicated that the surface soil contained concentrations of cesium-137 and strontium-90 that exceeded background levels established by the EPA. Because of the initial findings, followup sampling was initiated. As the EIR states: Consequently, further testing was indicated. Tritium was also detected in the samples, but at concentrations below the EPA background levels. A limited radiation survey was conducted during subsequent testing and analysis in the Phase I ESA for the 550-acre parcel referenced in this section. This assessment found that radiation levels were within normal background levels. Tritium and strontium-90 were not detected in any of the soil and groundwater samples at levels above normal background levels or at levels considered to pose a health risk. (emphasis added). This conclusion is puzzling, because the actual measurements being cited for the proposition that none were above background nor above levels considered to pose a health risk show precisely the opposite. Rather than none of the samples being above background or health risk levels, ALL 58 of the 1999 follow-up strontium measurements exceeded the 0.1 pCi/gram background figure cited in the EIR (as we shall see, that figure is actually twice background), and virtually all exceed the EPA’s Preliminary Remediation Goals (PRGs). This research was completed money allocated during Round 6 of the Citizens’ Monitoring and Technical Assessment Fund (MTA Fund). Clark University was named conservator of these works. If you have any questions or concerns please contact us at [email protected]://commons.clarku.edu/bridge_gap/1001/thumbnail.jp

    Radioactive Contamination of Water At the Santa Susana Field Laboratory

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    Presentation to SSFL InterAgency Work Group Community Meeting. Contains presentation slides in pdf format. This research was completed money allocated during Round 6 of the Citizens’ Monitoring and Technical Assessment Fund (MTA Fund). Clark University was named conservator of these works. If you have any questions or concerns please contact us at [email protected]://commons.clarku.edu/bridge_gap/1003/thumbnail.jp

    Nuclear Cleanup: The Standards Conflict

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    The U.S. Department of Energy has recently violated a longstanding Joint DOE-EPA Policy which commits DOE to clean up all its nuclear facilities nationwide to the Environmental Protection Agency (EPA) Superfund (CERCLA) standards. The focal point of this conflict between DOE and EPA cleanup standards is the Santa Susana Field Laboratory (SSFL), a 2800- acre facility on the Los Angeles-Ventura County line in Southern California. Ten reactors, a plutonium fuel facility, and a “hot laboratory” for cutting up irradiated nuclear fuel were operated at the facility, which opened in the 1940s when it was remote from populated areas. Now large numbers of people live nearby. One of the reactors suffered a partial meltdown in 1959; two others experienced damage in 1964 and 1969 to 80% and 35% of their fuel, respectively. In 1989, DOE found widespread chemical and radioactive contamination at the site, and a cleanup program commenced. In 1995, DOE and EPA entered into a Joint Policy to assure that all DOE sites, whether or not they were on the National Priority List (Superfund), would be cleaned up consistent with EPA’s CERCLA standards. In March of 2003, DOE reversed course and, while claiming to still follow the 1995 Policy, announced it would not clean the site up to the EPA standards. It would remove only 1% of the contaminated soil and then release the site for unrestricted residential use. In December 2003, EPA issued findings that the site was not being cleaned up consistent with the 1995 Joint Policy and that under the circumstances, so much radioactivity could be left in place that residential use would be unsafe and the only safe use would be restricted dayhikes with limitations on picnicking. To date no detailed study has been done comparing the DOE and EPA cleanup standards. This report, supported by a grant from the Citizens’ Monitoring and Technical Assistance Fund, performs that analysis. The evaluation demonstrates that DOE’s decision not to comply with EPA’s cleanup standards will result in radionuclide concentrations being permitted that are hundreds, thousands, tens of thousands, and in some cases, hundreds of thousands of times higher than EPA’s primary cleanup goals. For most radionuclides, the associated risk exceeds even the uppermost permissible risk level of EPA under CERCLA. In some cases, those cancer risks rise to levels on the order of one cancer per ten people exposed, using the federal government’s official radiation risk figures. Should DOE proceed with acting in contravention of the 1995 DOE-EPA Joint Policy on cleaning up DOE sites consistent with CERCLA at SSFL, there would be significant ramifications for the DOE nuclear complex nationwide, and for public health. This research was completed money allocated during Round 4 of the Citizens’ Monitoring and Technical Assessment Fund (MTA Fund). Clark University was named conservator of these works. If you have any questions or concerns please contact us at [email protected]://commons.clarku.edu/bridge_gap/1000/thumbnail.jp

    Auswirkungen einer kunsttherapeutischen Intervention auf die psychische Genesung nach Schlaganfall

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    Objectives This thesis is on the effects of art therapy, in this case the colouring of pictures, on the mental convalescence of patients with stroke. Stroke is a vascular disorder of the brain with a lack of oxygen and death of nerve cells in affected regions. Based on individually affected brain areas a variety of sensorimotor and cognitive impairments may result. Stroke is a major neurological problem and its socioeconomic relevance is enormous. The aim of the current thesis is to prove whether, how and how strong the colouring of pictures has an impact on stroke patients’ mental recovery. According to literature a positive effect might be assumed, which would also have therapeutic implications. Design & Methods To verify the hypothesis a total of 143 stroke patients were recruited according to respective inclusion and exclusion criteria and randomly divided into a test and a control group, matching with a randomized controlled prospective study design. The 76 patients of the test group received a colouring booklet, which they could design according to their ideas, additional to standardized stroke therapy on the Stroke Unit; the 67 patients of the control group received only standardized stroke therapy without art intervention. At three defined time points (i.e., at beginning of the art therapy, at end of the art therapy and eight weeks after end of the art therapy and at corresponding time in the control group) the following data were collected for all patients using questionnaires: the Hospital Anxiety and Depression Scale (HADS) to record anxiety and depressive disorders, the Resilience Scale 25 (RS-25) to quantify resilience and the Big Five Inventory (BFI) to ascertain the personality structure. The changes of scores over time were observed and compared between test and control groups. Observations & Results After eight weeks significant differences (p < 0.05) between the test and the control group could be detected for the HADS and the RS-25 and to a lesser extent also with the BFI. Most of the observed effect sizes (0.3 ≥ r ≤ 0.5) showed medium to strong differences between the test and the control group. Conclusions According to the present study it could be concluded that patients, who had the art intervention, recovered better and faster from mental deficits due to stroke compared to control patients. The fact that differences in the development of the patients’ personality structure could only be shown to a lesser extent is most likely due to the comparably short observation period. Considering the results and their interpretation it could be demonstrated that applying art has a positive effect on mental recovery of patients after stroke. The mental constitution of the patients, who had drawn during their inpatient stay, developed much more positive than that of patients, who had not. Hence, the hypothesis of the present thesis could be confirmed. Finally, this thesis may be seen as a basis for future examinations, which could for example have a variation of the length of the art intervention as topic, observe patients for a longer period of time or deal with the implementation of art therapy into clinical daily routine or the effects art therapy has on the physical constitution of patients with stroke.Hintergrund und Ziele Die vorliegende Arbeit beschäftigt sich mit den Auswirkungen von Kunsttherapie, in diesem Fall dem Ausmalen von Bildern, auf die psychische Genesung von Patienten nach Schlaganfall. Ein Schlaganfall ist eine Durchblutungsstörung des Gehirns mit Sauerstoffminderversorgung und Untergang von Nervenzellen in der betroffenen Region. Abhängig von den jeweils betroffenen Gehirnarealen können unterschiedlichste sensomotorische und kognitive Defizite die Folge sein. Der Schlaganfall ist ein sehr häufiges neurologisches Problem und seine sozioökonomische Bedeutung ist enorm. Das Ziel dieser Arbeit ist es, nachzuweisen, ob, inwiefern und wie stark sich das Ausmalen von Bildern auf die Erholung psychischer Funktionsstörungen bei Schlaganfallpatienten auswirkt. Eine positive Wirkung kann aufgrund der Datenlage angenommen werden, was auch therapeutische Implikationen hätte. Methoden (Patienten, Material und Untersuchungsmethoden) Zur Überprüfung der Hypothese wurden, dem Studiendesign einer randomisierten kontrollierten prospektiven Studie entsprechend, insgesamt 143 Schlaganfallpatienten nach bestimmten Ein- und Ausschlusskriterien rekrutiert und randomisiert in eine Test- und eine Kontrollgruppe eingeteilt. Die 76 Patienten der Testgruppe erhielten zusätzlich zur standardisierten Schlaganfalltherapie auf der Stroke Unit ein Malheft, das sie nach ihren Vorstellungen gestalten konnten; die 67 Patienten der Kontroll-gruppe erhielten nur die standardisierte Schlaganfalltherapie, ohne Kunstintervention. Zu drei definierten Zeitpunkten (d.h., zu Beginn der Kunsttherapie, am Ende der Kunsttherapie und acht Wochen nach Beendigung der Kunsttherapie bzw. zu korrespondierenden Zeitpunkten in der Kontrollgruppe) wurden bei sämtlichen Patienten mithilfe von Fragebögen folgende Scores erhoben: die Hospital Anxiety and Depression Scale (HADS) zur Erfassung von Angst- und depressiven Störungen, die Resilienzskala 25 (RS-25) zur Quantifizierung der Resilienz und das Big Five Inventory (BFI) zur Erhebung der Persönlichkeitsstruktur. Es wurden die Veränderungen der Scores über die Zeit beobachtet und zwischen Test- und Kontrollgruppe verglichen. Ergebnisse und Beobachtungen Nach Ablauf von acht Wochen konnten bei der HADS und der RS-25 und zu einem geringeren Ausmaß auch beim BFI signifikante Unterschiede (p < 0,05) zwischen Test- und Kontrollgruppe nachgewiesen werden. Die meisten der erzielten Effektstärken lagen in einem Bereich (0,3 ≥ r ≤ 0,5), in dem man von mittelstarken bis starken Unterschieden zwischen Test- und Kontrollgruppe sprechen kann. (Praktische) Schlussfolgerungen und Diskussion Aus der vorliegenden Studie ließ sich schlussfolgern, dass Patienten, die die Kunstintervention hatten, sich besser und schneller von den mit dem Schlaganfallereignis verbundenen psychischen Defiziten erholten als Kontrollpatienten. Die nur zu einem geringeren Ausmaß feststellbaren Unterschiede bei der Entwicklung der Persönlichkeitsstruktur (BFI) der Patienten sind vermutlich einem vergleichsweise kurzen Beobachtungszeitraum geschuldet. Ausgehend von den Ergebnissen und deren Interpretation konnte demonstriert werden, dass das Einsetzen von Kunst sich positiv auf den Genesungsprozess von Patienten nach Schlaganfall auswirkt. Die psychische Konstitution von Patienten, die während ihres stationären Aufenthalts gemalt hatten, entwickelte sich deutlich stärker positiv, als dies bei Patienten ohne Kunstintervention der Fall gewesen war. Die Hypothese der vorliegenden Arbeit konnte somit bestätigt werden. Zuletzt kann diese Arbeit als Grundlage für zukünftige Arbeiten dienen, die etwa die Auswirkungen einer Variation der Länge der künstlerischen Intervention zum Thema haben, Patienten über einen längeren Zeitraum beobachten oder sich mit der Implementierung von Kunsttherapie in den klinischen Alltag oder den Auswirkungen von Kunsttherapie auf die körperlichen Defizite von Schlaganfallpatienten beschäftigen

    Cryptographic applications of sparse polynomials over finite rings

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    This is a preprint of a book chapter published in Lecture Notes in Computer Science, 2015, Springer-Verlag, Berlin (2001). The original publication is available at www.springerlink.com.This paper gives new examples that exploit the idea of using sparse polynomials with restricted coefficients over a finite ring for designing fast, reliable cryptosystems and identification schemes
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