High-resolution methods for fluorescence retrieval from space

The retrieval from space of a very weak fluorescence signal was studied in the O2A and O2B oxygen atmospheric absorption bands. The accuracy of the method was tested for the retrieval of the chlorophyll fluorescence and reflectance terms contributing to the sensor signal. The radiance at the top of the atmosphere was simulated by means of a commercial radiative-transfer program at a high resolution (0.1 cm-1). A test data set was generated in order to simulate sun-induced chlorophyll fluorescence at the top of the canopy. Reflectance terms were spectrally modeled using cubic splines and fluorescence by means of the sum of two Voigt functions. Sensor radiance residual minimization was performed in the presence of a multiplicative noise, thus ensuring that the sensor simulations were realistic. The study, which focused on the possibility of retrieving fluorescence with an accuracy better than 10%, was performed for instrument resolutions ranging from about 0.4 cm-1 to 2 cm-1 in order to test the algorithm for the characteristics of existing and planned hyper-spectral sensors. The algorithm was also used to retrieve fluorescence in the single O2A band at the OCO and TANSO-FTS instrument spectral resolution

Portugal and South Africa: Close Allies or Unwilling Partners in Southern Africa during the Cold War?

The popular perception of the existence of a straightforward alliance between Portugal and South Africa as a result of the growing efficacy of African nationalist groups during the 1960s and early 1970s has never been seriously questioned. However, new research into recently declassified documents from the Portuguese military archives and an extensive overview of the Portuguese and South African diplomatic records from that period provide a different perception of what was certainly a complex interaction between the two countries. It should be noted that, although the two countries viewed their close interaction as mutually beneficial, the existing political differences effectively prevented the creation of an open strategic alliance that would have had a greater deterrence value instead of the secretive tactical approach that was used by both sides to resolve immediate security threats. In addition, South African support for Portugal’s long, difficult and costly counterinsurgency effort in three different operational theatres in Africa – Angola, Mozambique and Guinea Bissau – was not really decisive since such support was never provided on a significant scale

Regulatory parking policies at the firm level

Abstract. This paper is focused on the intersection of two main policy 'tracks ' followed in the Netherlands for the containment of road transport externalities: transport plans at the firm level, and regulatory parking policies. In this paper an applied modelling approach is taken, and the aim is to identify the relative importance of factors that are decisive for the viability of an individual firm's parking policies. The outcomes of an empirical survey conducted at the corporate level of the Free University in Amsterdam are used to discuss the social feasibility of regulatory parking policies conducted at the firm level (in terms of the employees ' attitudes) and the effectiveness of such policies. Insight is provided into relevant backgrounds and obstacles serving to affect employees' commuting behaviour and that are likely to be encountered in the formulation of regulatory transport policies at the firm level. Moreover, the outcomes of this research may be relevant for the evaluation of regulatory parking policies at larger spatial scales (for example, neighbourhood parking schemes).