Neighbourhoods and the implementation of city plans

This article addresses the alternatives posed by urban decentralization as a new institutional framework within which change in city planning goals and administrative practices can take place. Considering that, traditionally, the professions of city planning and public administration have been haunted by a low level of implementation of plans and a high level of dissatisfaction with public-service delivery, the attempt is made to identify the root causes of the two shortcomings. In the process, the thesis is sustained that neighbourhoods endowed with formal decision-making powers have the potential to increase the degree of implementation of plans and to ensure greater efficiency in, and satisfaction with, the delivery of public services. A case study provides a data base to illustrate a number of working hypotheses.     

Routes of Agulhas rings in the southeastern Cape Basin

Using weekly sea surface height data, Agulhas rings from the period October 1992 to December 2006 are detected and tracked, from their formation dates and throughout the Cape Basin. While 102 of them formed at the Agulhas Current retroflection, their subsequent subdivisions and junctions led to 199 trajectories. The rings geographical probability of presence shows two maxima. One, related to numerous ring passages, lies in the submarine bight formed by the Erica seamount, the Schmitt-Ott seamount, and the northeastern tip of the Agulhas Ridge. The other one, to be ascribed to topographic blocking of the eddies, is southeast of the latter obstacle. On the basis of topographic effects three routes for Agulhas rings are distinguished, a Northern route for rings that enter the south-Atlantic northeast of the Erica seamount, a Central one for those passing westward between this seamount and the tip of the Agulhas Ridge, and a Southern one farther south. Despite its bathymetric obstacles, the central route is the dominant one, both in terms of percentage of eddy crossings at its definition segment, and in terms of conveyed volume transport. Specific behaviours of rings along each route are described, referring to observations in previous studies. Some rings from the Northern route interact with the flow regime of the South African continental slope. The southernmost trajectories of the Central route are thought to settle the location of the climatological Subtropical Front in that region. The rings of the Southern route experience important core property alteration as they transit through the subantarctic domain.     

Towards a Validation of Scintillometer Measurements: The LITFASS-2009 Experiment

Scintillometry has been increasingly used over the last decade for the experimental determination of area-averaged turbulent fluxes at a horizontal scale of a few kilometres. Nevertheless, a number of assumptions in the scintillometer data processing and interpretation still call for a thorough evaluation, in particular over heterogeneous terrain. Moreover, a validation of the path-averaged structure parameters derived from scintillometer data (and forming the basis for the flux calculations) by independent measurements is still missing. To achieve this, the LITFASS-2009 field campaign has been performed around the Meteorological Observatory Lindenberg ?C Richard-A?mann-Observatory of the German Meteorological Service (DWD) in July 2009. The experiment combined tower-based in-situ turbulence measurements, field-scale laser scintillometers, long-range optical (large-aperture) and microwave scintillometers, and airborne turbulence measurements using an automatically operating unmanned aircraft. The paper describes the project design and strategy, and discusses first results. Daytime near-surface values of the temperature structure parameter, ${C_{T}^{2}}$ , over different types of farmland differ by more than one order of magnitude in their dependence on the type and status of the vegetation. Considerable spatial variability in ${C_{T}^{2}}$ was also found along the flight legs at heights between 50 and 100?m. However, it appeared difficult to separate the effects of heterogeneity from the temporal variability of the turbulence fields. Aircraft measurements and scintillometer data agreed in magnitude with respect to the temporal variation of the path-averaged ${C_{T}^{2}}$ values during the diurnal cycle. The decrease of ${C_{T}^{2}}$ with height found from the scintillometer measurements close to the surface and at 43?m under daytime convective conditions corresponds to free-convection scaling, whereas the aircraft measurements at 54 and 83?m suggest a different behaviour.     

Efficiency of calcein tagging on juveniles of the sea urchins Diadema africanum and Paracentrotus lividus

We evaluated the effectiveness of chemical tagging with the fluorescent marker calcein for two key species of herbivorous sea urchins, Diadema africanum and Paracentrotus lividus, to facilitate medium‐ and long‐term ecological experiments. In total, 98 juveniles of D. africanum and 98 P. lividus were tagged with this fluorescent marker, with 12 combinations of different tagging techniques (chemical bath or injection), concentrations of calcein (2, 10 and 20 mg · l^?1), and soaking times (2, 4 and 24 h). Respective control treatments were conducted by means of seawater injection and bathing. The success of tagging was assessed after a month of feeding individuals ad libitum with the algae Dictyota sp. Sea urchins were dissected and their Aristotle's lanterns cleaned with 10% sodium hypochlorite to examine these structures under UV light using a binocular microscope. Each species was evaluated in terms of survival, percentage of tagged individuals and intensity of the resulting tag. The results showed that the method of soaking individuals of both species for 24 h in concentrations of calcein of 10 and 20 mg · l^?1 gave the highest percentage survival (100%) and the resulting tags were clearly visible.     

Airborne detection of ecosystem responses to an extreme event: Phytoplankton displacement and abundance after hurricane induced flooding in the Pamlico-Albemarle Sound system,North Carolina

Airborne laser-induced fluorescence measurements were used to detect and monitor ecosystem wide changes in the distribution and concentration of chlorophyll biomass and colored dissolved organic matter in the Pamlico-Albemarle Sound system, North Carolina, U.S., following massive flooding caused by a series of three hurricanes in the late summer of 1999. These high-resolution data provided a significantly more detailed representation of the overall changes occurring in the system than could have been achieved by synoptic sampling from any other platform. The response time for the distribution of chlorophyll biomass to resume pre-flood conditions was used as a measure of ecosystem stability. Chlorophyll biomass patterns were reestablished within four mo of the flooding, whereas higher chlorophylla biomass concentrations persisted for approximately 6 mo. The primary trophic level in the Pamlico-Albemarle Sound system returned to equilibrium in less than a year of a major perturbation.     

On the detection of (habitable) super-Earths around low-mass stars using Kepler and transit timing variation method

We present the results of an extensive study of the detectability of Earth-sized planets and super-Earths in the habitable zones of cool and low-mass stars using transit timing variation method. We have considered a system consisting of a star, a transiting giant planet, and a terrestrial-class perturber, and calculated TTVs for different values of the parameters of the system. To identify ranges of the parameters for which these variations would be detectable by Kepler, we considered the analysis presented by Ford et?al. (Transit timing observations from Kepler: I. Statistical analysis of the first four months. ArXiv:1102.0544, 2011) and assumed that a peak-to-peak variation of 20 s would be within the range of the photometric sensitivity of this telescope. We carried out simulations for resonant and non-resonant orbits, and identified ranges of the semimajor axes and eccentricities of the transiting and perturbing bodies for which an Earth-sized planet or a super-Earth in the habitable zone of a low-mass star would produce such TTVs. Results of our simulations indicate that in general, outer perturbers near first- and second-order resonances show a higher prospect for detection. Inner perturbers are potentially detectable only when near 1:2 and 1:3 mean-motion resonances. For a typical M star with a Jupiter-mass transiting planet, for instance, an Earth-mass perturber in the habitable zone can produce detectable TTVs when the orbit of the transiting planet is between 15 and 80 days. We present the details of our simulations and discuss the implication of the results for the detection of terrestrial planets around different low-mass stars.     

Geodetic techniques applied to the study of the Etna volcano area (Italy)

Volcanic behaviour of Mt. Etna is due to the complex interaction between both the local and the regional stress field involving the eastern Sicily. Eruptions could trigger (be triggered?) during crust extension and/or compression, which are strictly linked with the dynamics of the lower mantle. In this study, very long baseline interferometry (VLBI) space geodesy technique has been used in order to study Etna volcano’s activity by means of the crustal deformations between Noto and Matera (located on the African and the Eurasian Plates, respectively). By analysing VLBI data, we obtained the behaviour of the baseline which crosses the Etnean area, from 1990 December to 2003 March, representing the time variations of the distance between the two geodetic stations; the linear trend of the baseline shows a general increasing, pointing out an extension of the crust between them. A detailed analysis of the Noto-Matera baseline allows the identification of three parts of the VLBI curve in the considered period. In the first part of the curve (from 20/12/90 to 09/02/94), VLBI data are rather poor and therefore no reliable consideration about correlation between crust movements and volcanic and seismicity activity has been made. In the second part of the curve (from 09/02/94 to 04/09/00), VLBI data are more frequent and show slightly fluctuations in the distance. Increasing in the extension and compression were observed in the central and in the final part of this period. In the third period (from 04/09/00 to 25/03/03), VLBI data are very sparse even if the time series was quite long; therefore, to fill gaps in the information, we analysed global positioning system (GPS) data. GPS technique performs continuous observations, and we were able to highlight both extensions and compressions in detail. Comparisons between the trend of Noto-Matera baseline length variations, volcanic activity and seismicity in the Etna area show the complexity of the development over time and space of the phenomenology determined by a deep cause which can be traced, in our opinion, to the interaction between the asthenospheric mantle, deep crust and surface crust. Therefore, we state that crustal distension and compression are determined by the lower pulsating mantle.