1,483 research outputs found

    Dynamics of the solar magnetic bright points derived from their horizontal motions

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    The sub-arcsec bright points (BP) associated with the small scale magnetic fields in the lower solar atmosphere are advected by the evolution of the photospheric granules. We measure various quantities related to the horizontal motions of the BPs observed in two wavelengths, including the velocity auto-correlation function. A 1 hr time sequence of wideband Hα\alpha observations conducted at the \textit{Swedish 1-m Solar Telescope} (\textit{SST}), and a 4 hr \textit{Hinode} \textit{G}-band time sequence observed with the Solar Optical telescope are used in this work. We follow 97 \textit{SST} and 212 \textit{Hinode} BPs with 3800 and 1950 individual velocity measurements respectively. For its high cadence of 5 s as compared to 30 s for \textit{Hinode} data, we emphasize more on the results from \textit{SST} data. The BP positional uncertainty achieved by \textit{SST} is as low as 3 km. The position errors contribute 0.75 km2^2 s−2^{-2} to the variance of the observed velocities. The \textit{raw} and \textit{corrected} velocity measurements in both directions, i.e., (vx,vy)(v_x,v_y), have Gaussian distributions with standard deviations of (1.32,1.22)(1.32,1.22) and (1.00,0.86)(1.00, 0.86) km s−1^{-1} respectively. The BP motions have correlation times of about 22−3022 - 30 s. We construct the power spectrum of the horizontal motions as a function of frequency, a quantity that is useful and relevant to the studies of generation of Alfv\'en waves. Photospheric turbulent diffusion at time scales less than 200 s is found to satisfy a power law with an index of 1.59.Comment: Accepted for publication in The Astrophysical Journal. 24 pages, 9 figures, and 1 movie (not included

    Wind voor of wind tegen: windenergie op agrarische bedrijven

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    De Nederlandse overheid streeft naar een windenergievermogen op land van 4.000 MW in 2011, een verdubbeling van het huidige vermogen. Kan de agrarische sector een bijdrage leveren aan deze ambitieuze doelstelling? Om hier enig inzicht in te krijgen is in dit onderzoek gekeken naar de huidige situatie in de agrarische windenergiesector. Aan de orde komen hier structuurkenmerken, de bijdrage aan de nationale energievoorziening en bedrijfseconomische effecten op het agrarische bedrijf

    The importance of sensitive parenting: A longitudinal adoption study on maternal sensitivity, problem behavior, and cortisol secretion

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    The current thesis focuses on the longitudinal development of early-adopted children in the 1887/29874 Leiden Longitudinal Adoption Study (LLAS). In the LLAS, adopted children were followed from infancy until young adulthood. In Chapter 1 we discuss the role of sensitive parenting and the precursors and developmental outcomes of attachment security. In the empirical study in Chapter 2 we report on the concurrent as well as longitudinal relations between maternal sensitivity, child temperament, and externalizing behavior problems. In the second empirical study in Chapter 3, we follow this line of enquiry and investigate concurrent and longitudinal relations between maternal sensitivity, child temperament and internalizing behavior problems. Chapter 4 reports on the final empirical study of the thesis, and focuses on the associations between maternal sensitivity and attachment in infancy and the diurnal cortisol curve in young adulthood. Our empirical studies show that maternal sensitivity in infancy and middle childhood indirectly predicts fewer internalizing behavior problems in adopted adolescents, and that maternal sensitivity in adolescence predicts less concurrent delinquent behavior. Attachment experiences in early life do not predict the adoptees' diurnal cortisol curve in later life. In Chapter 5 we discuss these results and some methodological issues more thoroughly.NWO Spinoza, VIDI grant no. 452-04-306; VICI grand no. 453-09-003, Wereldkinderen NWODevelopment Psychopathology in context: famil

    Trust in Dutch intensive care networks:the results of a survey

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    Introduction: Dutch ICUs have been enrolled in network organisations since the Quality Standard of 2016. In networks, intensivists have to cooperate to provide a high quality of care for all patients in their network. Trust is essential to cooperate effectively in a network. It is unknown what the degree of trust is in Dutch ICU networks. Methods: A survey was composed using the questionnaire by Cummings, measuring the experience of trust, and the questionnaire by Currall, measuring the willingness to show behaviour that is consistent with trust. Two overall questions concerning the feeling of being part of the network and the overall level of trust were added. All questions were answered on a 7-point Likert scale. Network managers passed the questionnaire to intensivists in the network. Results: The overall level of trust showed a mean of 5.5 (SD 1.2), similar to the mean of the Cummings questionnaire (5.3; SD 0.9). Academic intensivists had a significantly higher level of trust than intensivists from other hospitals (5.9 vs 5.0 and 5.3; p=0.009). The questions covering `surveillance', which measures the need for control, scored lowest with 3.8 (SD 1.3). Intensivists feel the need to make formal agreements and they experience a relatively intense need to control these agreements. Conclusion: Intensivists experience a reasonable level of trust within their network. However, intensivists feel the need to make formal agreements and they experience a relatively intense need to control these agreements. This suggests that the actual trust is conditional. Academic intensivists showed the highest level of trust

    Trust in Dutch intensive care networks:the results of a survey

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    Introduction: Dutch ICUs have been enrolled in network organisations since the Quality Standard of 2016. In networks, intensivists have to cooperate to provide a high quality of care for all patients in their network. Trust is essential to cooperate effectively in a network. It is unknown what the degree of trust is in Dutch ICU networks. Methods: A survey was composed using the questionnaire by Cummings, measuring the experience of trust, and the questionnaire by Currall, measuring the willingness to show behaviour that is consistent with trust. Two overall questions concerning the feeling of being part of the network and the overall level of trust were added. All questions were answered on a 7-point Likert scale. Network managers passed the questionnaire to intensivists in the network. Results: The overall level of trust showed a mean of 5.5 (SD 1.2), similar to the mean of the Cummings questionnaire (5.3; SD 0.9). Academic intensivists had a significantly higher level of trust than intensivists from other hospitals (5.9 vs 5.0 and 5.3; p=0.009). The questions covering `surveillance', which measures the need for control, scored lowest with 3.8 (SD 1.3). Intensivists feel the need to make formal agreements and they experience a relatively intense need to control these agreements. Conclusion: Intensivists experience a reasonable level of trust within their network. However, intensivists feel the need to make formal agreements and they experience a relatively intense need to control these agreements. This suggests that the actual trust is conditional. Academic intensivists showed the highest level of trust

    Network governance of Dutch intensive care units:state of affairs after implementation of the Quality Standard

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    Objective: To study the current state of affairs concerning Dutch intensive care network governance in relation to known effective governance structures of network organisations. Methods: Six characteristics of intensive care networks were defined to determine the four contingency factors from the Provan & Kenis network governance models. The contingency factors were determined for all Dutch intensive care networks. An overview of the networks and characteristics was created by triangulation, using information from two national intensive care network meetings (November 2017 and June 2018) and semi-structured interviews by telephone with 10 network intensivists and / or network managers. Results: Based on the chosen characteristics, none of the Dutch intensive care networks has a governance structure according to one of the Provan & Kenis successful forms of governance. Each of the present networks has a governance structure with elements from two or three different types. Characteristics of the network administrative organisation and shared governance form overlap in 10 out of 15 networks. All networks have a form of governance in which at least one intensivist is represented. Conclusion: After implementation of the Quality Standard, the presence of networks of intensive care units covering the Netherlands is a fact. The network governance that has developed varies but none of the networks has a governance structure that matches with a proven effective governance structure. Based on theory, the network administrative organisation seems to be the most effective for larger networks, and shared governance for smaller networks
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