834 research outputs found

    Secondary electron emission from meteoric smoke particles inside the polar ionosphere

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    The charging by secondary electron emission (SEE) from particles is known as a significant charging process in astrophysical plasmas. This work aims at evaluating the significance of SEE for charging of meteoric smoke particles (MSPs) in the Earth's polar atmosphere. Here, the atmosphere is subject to a bombardment of energetic electrons from the magnetosphere (and partly the sun). We employ the SEE formalism to MSPs in the upper mesosphere using electron precipitation fluxes for three different precipitation strengths. In addition, we address the possible effect of tertiary electron emission (TEE) from MSPs induced by atmospheric secondary electrons for one precipitation case. The SEE and TEE rates from MSPs of different sizes are compared to plasma attachment and photodetachment and photoionization rates of MSPs. The needed concentration of electrons and ions have been modeled with the Sodankyla Ion and Neutral Chemistry (SIC) model with included electron precipitation spectra as an additional ionization source. We find that secondary electron emission from MSPs is not a relevant charging mechanism for MSPs. The electron attachment to MSPs and photodetachment of negatively charged MSPs are the most important processes also during energetic electron precipitation

    Secondary electron emission from meteoric smoke particles inside the polar ionosphere

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    The charging by secondary electron emission (SEE) from particles is known as a significant charging process in astrophysical plasmas. This work aims at evaluating the significance of SEE for charging of meteoric smoke particles (MSPs) in the Earth's polar atmosphere. Here, the atmosphere is subject to a bombardment of energetic electrons from the magnetosphere (and partly the sun). We employ the SEE formalism to MSPs in the upper mesosphere using electron precipitation fluxes for three different precipitation strengths. In addition, we address the possible effect of tertiary electron emission (TEE) from MSPs induced by atmospheric secondary electrons for one precipitation case. The SEE and TEE rates from MSPs of different sizes are compared to plasma attachment and photodetachment and photoionization rates of MSPs. The needed concentration of electrons and ions have been modeled with the Sodankyla Ion and Neutral Chemistry (SIC) model with included electron precipitation spectra as an additional ionization source. We find that secondary electron emission from MSPs is not a relevant charging mechanism for MSPs. The electron attachment to MSPs and photodetachment of negatively charged MSPs are the most important processes also during energetic electron precipitation

    The Geminid meteor shower during the ECOMA sounding rocket campaign: specular and head echo radar observations

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    The ECOMA (Existence of Charge state Of meteoric smoke particles in the Middle Atmosphere) sounding rocket campaign was conducted during the Geminid meteor shower in December 2010 in order to explore whether there is a change of the properties of meteoric smoke particles due to the stream. In parallel to the rocket flights, three radars monitored the Geminid activity located at the launch site in Northern Norway and in Northern Germany to gain information about the meteor flux into the atmosphere. The results presented here are based on specular meteor radar observations measuring the radiant position, the velocity and the meteor flux into the atmosphere during the Geminids. Further, the MAARSY (Middle Atmosphere Alomar Radar System) radar was operated to conduct meteor head echo experiments. The interferometric capabilities of MAARSY permit measuring the meteor trajectories within the radar beam and to determine the source radiant and geocentric meteor velocity, as well as to compute the meteor orbit

    The Impact of Social Isolation on Pain Interference: A Longitudinal Study

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    Background: Evidence suggests social interactions play an important role in pain perception. Purpose: The aim of this study was to determine whether social isolation (SI) in people with persistent pain determines pain interference (PI) and physical function over time. Methods: Patients seeking care at a tertiary pain management referral center were administered the Patient Reported Outcome Measurement Information System (PROMIS®) SI, PI, physical function, depression, and average pain intensity item banks at their initial consultation and subsequent visits as part of their routine clinical care. We used a post hoc simulation of an experiment using propensity score matching (n = 4,950) and carried out a cross-lagged longitudinal analysis (n = 312) of retrospective observational data. Results: Cross-lagged longitudinal analysis showed that SI predicted PI at the next time point, above and beyond the effects of pain intensity and covariates, but not vice versa. Conclusions: These data support the importance of SI as a factor in pain-related appraisal and coping and demonstrate that a comprehensive assessment of the individuals' social context can provide a better understanding of the differential trajectories for a person living with pain. Our study provides evidence that the impact of pain is reduced in individuals who perceive a greater sense of inclusion from and engagement with others. This study enhances the understanding of how social factors affect pain and have implications for how the effectiveness of therapeutic interventions may be improved. Therapeutic interventions aimed at increasing social connection hold merit in reducing the impact of pain on engagement with activities

    Unternehmerische Führung in Sozialen Organisationen

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    Sozialunternehmen mit einer ausgeprägt unternehmerischen Führung sind erfolgreicher als solche, die weniger stark veränderungs- und marktorientiert ausgerichtet sind, weniger Risiken eingehen, und ihre Mitarbeitenden weniger stark einbeziehen. Das zeigen die Ergebnisse einer Befragung von 257 Sozialen Organisationen aus der ganzen Schweiz, die im Bereich der Integration Wohn-, Arbeits-, Bildungs- oder Beratungsdienstleistungen für Klienten anbie-ten und sich dabei noch überwiegend über Leistungsverträge oder andere öffentliche Gelder (z.B. Kostengutsprachen) finanzieren. Der Organisationserfolg wurde dabei mit Bezug auf die Stakeholderzufriedenheit, die Mitarbeiterfluktuation, das Orga-nisationswachstum und die Veränderung in der Marktfinanzierung gemessen. Das letztgenannte Erfolgsmass spielt angesichts knapper werdender öf-fentlicher Finanzmittel eine zunehmend wichtige Rolle. Die relevanten Erfolgsfaktoren unterscheiden sich dabei je nach Erfolgsmass. Neben einer unter-nehmerischen Führung spielen auch die Wertekongruenz zwischen der haupt- und der ehrenamtlichen Leitung, die Verankerung der Organisationsstrategie, die organisationsinterne Kommunikation und die Organisationsstruktur eine entscheidende Rolle für die Zielerreichung

    The impact of social isolation on pain interference : a longitudinal study

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    Online-first April 2018Background: Evidence suggests social interactions play an important role in pain perception. Purpose: The aim of this study was to determine whether social isolation (SI) in people with persistent pain determines pain interference (PI) and physical function over time. Methods: Patients seeking care at a tertiary pain management referral center were administered the Patient Reported Outcome Measurement Information System (PROMIS®) SI, PI, physical function, depression, and average pain intensity item banks at their initial consultation and subsequent visits as part of their routine clinical care. We used a post hoc simulation of an experiment using propensity score matching (n = 4,950) and carried out a cross-lagged longitudinal analysis (n = 312) of retrospective observational data. Results: Cross-lagged longitudinal analysis showed that SI predicted PI at the next time point, above and beyond the effects of pain intensity and covariates, but not vice versa. Conclusions: These data support the importance of SI as a factor in pain-related appraisal and coping and demonstrate that a comprehensive assessment of the individuals’ social context can provide a better understanding of the differential trajectories for a person living with pain. Our study provides evidence that the impact of pain is reduced in individuals who perceive a greater sense of inclusion from and engagement with others. This study enhances the understanding of how social factors affect pain and have implications for how the effectiveness of therapeutic interventions may be improved. Therapeutic interventions aimed at increasing social connection hold merit in reducing the impact of pain on engagement with activities

    Design Hourly Volume Estimation at Freeway Nodes from Short-Term Traffic Counts

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    This paper extends the concept of a design hourly volume (DHV) which is derived from the ‘nth hour’ to a concept based on the nth highest saturated hour. To calculate this nth highest saturated hour at each ramp junction of a node, permanent traffic counts (PTC) are necessary on all ramps and the main lanes. In practice, such counts are often not available. For such cases, the German HCM proposes a method that enables the estimation of the design hourly volume through short-term traffic counts (STC) and the extrapolation of the results using available PTC in the vicinity. Within the scope of this study, it is examined how accurate the required nth highest saturated hour can be estimated with this method and similar concepts. Furthermore, it is investigated to what extent the number and the location of the available PTC affect the accuracy of the estimation. Scenarios without PTC are also considered. The evaluation is based on a database with a total of 72 freeway nodes for which PTC data from three years (2017-2019) are processed. The results show that the estimation of the nth highest saturated hour with the method of the German HCM works accurately, even if only one PTC is available on each inflowing approach. The results further indicate that STC are crucial to achieve accurate results when only few PTC are available. Acceptable results are also obtained by STC of one week, even without a projection at a PTC
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