Infrasound as upper atmospheric monitor

Understanding and specification of the higher altitudes of the atmosphere with global coverage over all local times is hampered by the challenges of obtaining direct measurements in the upper atmosphere. Methods to measure the properties of the atmosphere above the stratopause is an active area of scientific research. In this thesis, we revisit the use of infrasound as a passive remote sensing technique for the upper atmosphere. Signals from the Tungurahua volcano in Ecuador are used to investigate the behavior of the upper atmosphere. Depending on the atmospheric conditions, stratospheric, mesospheric and thermospheric arrivals are observed during intervals of explosive volcanic activity. It is found that the travel times and dominant frequencies of the thermospheric arrivals exhibit a coherent variability with periods equal to those of the tidal harmonics. Theoretical predictions using atmospheric specifications show that the stratospheric arrivals are predicted within 1% of the observed value. For thermospheric arrivals, this error can be as high as 10%. The error in thermospheric celerities is found to be in accord with the typical uncertainty in upper atmospheric winds. Given the observed response of the infrasound celerities to upper atmospheric tidal variability, it is suggested that infrasound observations may be used as an additional source of information to constrain the atmospheric specifications in the upper atmosphere. We present corrected wind profiles that have been obtained by minimizing misfits in traveltime and source location using a Bayesian statistics grid search algorithm. Also, a Levenberg-Marquardt search algorithm is developed. Additionally, a new numerical method has been developed to solve the problem of infrasound propagation in a stratified medium with (high Mach number) background flow, based on a modal expansion. The underlying mathematics is by no means new and has been earlier described. This solution goes beyond the effective sound speed approximation, which is typically used in infrasound propagation modeling for computational efficiency reasons. Using the wide-angle high Mach number modal solution, it is shown that traveltimes and shadow zones are under predicted using the effective sound speed approximation, with increasing grazing angle and Mach number

Spatial quality, location theory and spatial planning

This paper deals with spatial quality as a possible factor in location choices made by companies. Actual location decisions as well as location theory have changed over time. In the industrial era primary “hard” cost factors were dominant, to be supplemented by agglomeration factors ever since the 1950s. Over the last decades “soft” tertiary factors (like institutional “thickness”) became important, as reflected in behavioural and institutional theories on location choices. In this paper it is argued that due to socio-economic developments like globalization, the emergence of network societies, of knowledge-based economies and of creative economies, spatial quality has become a powerful factor in location choice. Because of an ever increasing level playing field, increased footlooseness of organizations and the post-scarcity effect, hard as well as soft primary, secondary and tertiary location factors are of increasingly limited importance. Consequently, spatial quality may be considered to be the dominant location factor of our time

Rechterlijke toetsing van bestuurlijk gedrag: binnen het vennootschapsrecht van Nederland en Delaware

In deze studie staat centraal de vraag hoe – kort gezegd – de rechter binnen het Nederlandse vennootschapsrecht op systematische(r) wijze het bestuurlijk gedrag in de context van gevoerd ondernemingsbeleid kan toetsen. Daarbij richt de analyse zich op het frequent toegepaste enquêterecht en bestuurdersaansprakelijkheid in de zin van art. 2:9 BW (dat ziet op persoonlijke aansprakelijkheid van de bestuurder(s) jegens de vennootschap wegens 'onbehoorlijke taakvervulling'). Aan rechterlijke toetsing van bestuurlijk gedrag in de context van gevoerd ondernemingsbeleid zitten diverse haken en ogen, die in het eerste hoofdstuk in kaart worden gebracht. Daarbij wordt ook ingegaan op de ratio van beperkte rechterlijke toetsing van bestuurlijk gedrag en de wijze waarop daaraan invulling wordt gegeven binnen het Nederlandse vennootschapsrecht. Vervolgens wordt ter inspiratie in hoofdstukken 2-4 bezien hoe binnen het vennootschapsrecht van Delaware rekening wordt gehouden met voornoemde haken en ogen. Daarbij speelt de rechtsfiguur business judgment rule, een begrenzer van de rechterlijke toetsingsvrijheid, een voorname rol. Een kernaspect van deze rechtsfiguur is dat de rechter het gedrag van het ondernemende bestuur in beginsel niet op redelijkheid/billijkheid mag toetsen. Zo streng voor het bestuur mag de rechter niet zijn, tenzij het bestuur bijvoorbeeld geraakt wordt door een dusdanig persoonlijk – niet aan het belang van de vennootschap parallel lopend – belang dat het risico van belangenvermenging ten detrimente van de vennootschap aanwezig is. Binnen het Nederlandse vennootschapsrecht wordt vaak het vage begrip 'marginale' toetsing gebruikt, waarmee in wezen wordt gedoeld op een – inhoudelijke – redelijkheidstoets. Milder dan dat toetst de rechter het bestuurlijk gedrag doorgaans niet, ook niet wanneer de tegenstrijdig belang problematiek niet speelt. In hoofdstuk 5 wordt de blik weer gericht op het Nederlandse vennootschapsrecht en worden – de verhouding tussen – de kernbegrippen als gehanteerd binnen het enquêterecht geanalyseerd: 'wanbeleid', 'onjuist beleid' en 'gegronde redenen om aan een juist beleid te twijfelen'. In hoofdstukken 6-7 wordt vervolgens – op basis van de bevindingen in hoofdstukken 1-5 – een nuancering bepleit van de wijze waarop de Ondernemingskamer in enquêteprocedures bestuurlijk gedrag dient te toetsen, waarbij de Nederlandse variant van de business judgment rule als in deze studie voorgestaan een belangrijke rol speelt. Daarbij wordt een werkmethode uiteengezet die de Ondernemingskamer handvatten biedt bij de toetsing van gedrag van het ondernemende bestuur. Nadat de werkmethode is toegepast op een zestal enquêtebeschikkingen van de Ondernemingskamer wordt deze, inclusief de Nederlandse variant van de business judgment rule, ten slotte ingepast in de systematiek van art. 2:9 BW.Op de volledige tekst van dit proefschrift rust een embargo van 12 maanden. Van dit proefschrift is tevens een handelseditie verschenen in de serie Uitgaven vanwege het Instituut voor Ondernemingsrecht, Rijksuniversiteit Groningen, nr. 59, onder ISBN 978 90 13 04772 1, Kluwer, 2007

Placental transfer of a hydroxylated polychlorinated biphenyl and effects on fetal and maternal thyroid hormone homeostasis in the rat

Earlier studies at our laboratory indicated that several hydroxylated polychlorinated biphenyls (OH-PCBs) detected in human blood could specifically inhibit thyroxine (T4) transport by competitive binding to the thyroid hormone transport protein transthyretin (TTR) in vitro. In the present study we investigated the effects of prenatal exposure to 5 mg/kg body weight of [14C]-labeled or unlabeled 4-OH-2,3,3',4',5-pentachlorobiphenyl (4-OH-CB107), one of the major metabolites of PCBs detected in human blood, from gestation days (GD) 10 to 16 on thyroid hormone status and metabolism in pregnant rats and their fetuses at GD 17 and GD 20. 4-OH-CB107 is a metabolite of both 2,3,3',4,4'-pentachlorobiphenyl (CB-105) and 2,3',4,4',5-pentachlorobiphenyl (CB-118). We were able to show the accumulation of 4-OH-CB107 in the fetal compartment. The fetal/maternal ratios at GD 20 in liver, cerebellum, and plasma were 11.0, 2.6, and 1.2, respectively. The 14C-4-OH-CB107-derived radioactivity in plasma was bound to TTR in both dams and fetuses. Fetal plasma TT4 and FT4 levels were significantly decreased at GD 17 and GD 20 (89 and 41␛espectively at GD 20). Fetal thyroid stimulating hormone levels were increased by 124 at GD 20. The T4 concentrations in fetal forebrain homogenates at GD20 were reduced by 35°but no effects could be detected on brain T3 concentrations. The deiodination of T4 to T3 was significantly increased in fetal forebrain homogenates at GD 17, and unaltered at GD 20. In addition, no alterations were observed in maternal and fetal hepatic T4-UDP-glucuronosyltransferase activity, type I deiodinase activity, and EROD activity. In conclusion, exposure of pregnant rats to 4-OH-CB107 results in the distribution of the compound in the maternal and fetal compartment, which is probably caused by the binding of the PCB metabolite to TTR. Consequently, TT4 levels in fetal plasma and brain samples were reduced. Despite reductions in fetal brain T4 levels, the active hormone (T3) in fetal brains remained unaffected

The development and validation of an actuarial risk assessment tool for the prediction of first-time offending

For prevention purposes, it is important that police officers can estimate the risk for delinquency among juveniles who were involved in a criminal offense, but not in the role of a suspect. In the present study, the Youth Actuarial Risk Assessment Tool for First-Time Offending (Y-ARAT-FO) was developed based solely on police records with the aim to enable Dutch police officers to predict the risk for first-time offending. For the construction of this initial screening instrument, an Exhaustive Chi-squared Automatic Interaction Detector (Exhaustive CHAID) analysis was performed on a data set that was retrieved from the Dutch police system. The Y-ARAT-FO was developed on a sample of 1,368 juveniles and validated on a different sample of 886 juveniles showing moderate predictive accuracy in the validation sample (area under the receiver operating characteristic curve [AUC] = .728). The predictive accuracy of the Y-ARAT-FO was considered sufficient to justify its use as an initial screening instrument by the Dutch police