Participatory slum upgrading as a disjunctive process in Recife,Brazil: Urban coproduction and the absent ground of the city

This article engages with the coproduction of urban space by focusing on a slum upgrading project in Recife, Brazil. It argues that the urban situation is essentially inconsistent, unpredictable and unstable. It documents the history of urban planning in Recife, paying special attention to the coexistence of two different planning traditions, one aimed at what city planners call the informal city, which is participatory, bottom up and democratic, yet susceptible to be corrupted by political clientelism, and another aimed at the formal city, which is ‘strategic’, top down, technocratic and neoliberal. It argues that the informal/formal binary operates as a disjunctive synthesis that separates social actors rather than connecting them and provides the coordinates within which processes of coproduction take place. The disjunctive synthesis renders possible all sorts of fantastic imaginations that both disavow and reveal the missing ground of the city. Community leaders play a central role in the coproduction of urban space and function as the symptom of this absent ground. The article concludes that participatory urban development interventions aiming to curtail the role of community leaders end up as veritable tyrannies of participation, which should be seen as evidence of the disjointed character of planning rather than as forms of effective governmentality.     

Separation of rifting and lithospheric folding signatures in the NW-Alpine foreland

The development of the Alpine mountain belt has been governed by the convergence of the African and European plates since the Late Cretaceous. During the Cenozoic, this orogeny was accompanied with two major kinds of intraplate deformation in the NW-European foreland: (1) the European Cenozoic Rift System (ECRIS), a left-lateral transtensional wrench zone striking NNE-SSW between the western Mediterranean Sea and the Bohemian Massif; (2) long-wavelength lithospheric folds striking NE and located between the Alpine front and the North Sea. The present-day geometry of the European crust comprises the signatures of these two events superimposed on all preceding ones. In order to better define the processes and causes of each event, we identify and separate their respective geometrical signatures on depth maps of the pre-Mesozoic basement and of the Moho. We derive the respective timing of rifting and folding from sedimentary accumulation curves computed for selected locations of the Upper Rhine Graben. From this geometrical and chronological separation, we infer that the ECRIS developed mostly from 37 to 17 Ma, in response to north-directed impingement of Adria into the European plate. Lithospheric folds developed between 17 and 0 Ma, after the azimuth of relative displacement between Adria and Europe turned counter-clockwise to NW–SE. The geometry of these folds (wavelength = 270 km; amplitude = 1,500 m) is consistent with the geometry, as predicted by analogue and numerical models, of buckle folds produced by horizontal shortening of the whole lithosphere. The development of the folds resulted in ca. 1,000 m of rock uplift along the hinge lines of the anticlines (Burgundy–Swabian Jura and Normandy–Vogelsberg) and ca. 500 m of rock subsidence along the hinge line of the intervening syncline (Sologne–Franconian Basin). The grabens of the ECRIS were tilted by the development of the folds, and their rift-related sedimentary infill was reduced on anticlines, while sedimentary accumulation was enhanced in synclines. We interpret the occurrence of Miocene volcanic activity and of topographic highs, and the basement and Moho configurations in the Vosges–Black Forest area and in the Rhenish Massif as interference patterns between linear lithospheric anticlines and linear grabens, rather than as signatures of asthenospheric plumes.

Cosmic-ray positrons: are there primary sources?

Galactic cosmic rays consist of primary and secondary particles. Primary cosmic rays are thought to be energized by first order Fermi acceleration processes at supernova shock fronts within our Galaxy. The cosmic rays that eventually reach the Earth from this source are mainly protons and atomic nuclei, but also include electrons. Secondary cosmic rays are created in collisions of primary particles with the diffuse interstellar gas. They are relatively rare but carry important information on the Galactic propagation of the primary particles. The secondary component includes a small fraction of antimatter particles, positrons and antiprotons. In addition, positrons and antiprotons may also come from unusual sources and possibly provide insight into new physics. For instance, the annihilation of heavy supersymmetric dark matter particles within the Galactic halo could lead to positrons or antiprotons with distinctive energy signatures. With the High-Energy Antimatter Telescope (HEAT) balloon-borne instrument, we have measured the abundances of positrons and electrons at energies between 1 and 50 GeV. The data suggest that indeed a small additional antimatter component may be present that cannot be explained by a purely secondary production mechanism. Here we describe the signature of the effect and discuss its possible origin.     

Old, Low-Mass, Metal-Rich (SMR) Stars

The authors of this paper try to disentangle the many problems arisen from a new enlarged sample of nearby low-mass,metal-rich-stars. These stars have reliable absolute magnitudes, deduced from Hipparcos parallaxes, precise bolometric corrections, effective temperatures and metal abundances from high resolution detailed spectroscopic analyses. Their ages have been derived from a grid of isochrones calculated with up to date physics. The main goal of this paper is to determine the ages of the slightly evolved SMR stars. Among those with well determinated ages about 80% of them have intermediate ages of (2 to 5 Gyr), but only 20% have ages of 8 Gyr or more. Nevertheless, the existence of very old metal-rich stars is confirmed. This revised version was published online in July 2006 with corrections to the Cover Date.     

The journey to work: a century of change

Summary The paper uses original quantitative and qualitative evidence to examine changes in the distance travelled and time spent on the journey to work in twentieth-century Britain. Emphasis is placed on variations by gender and location, and on the implications of modal change. We suggest that analysis of past commuting trends may have implications for contemporary transport policy.     

白刺不同果实性状的遗传力估计及优良亲本选择

亲子回归法研究白刺果实不同性状遗传力的结果表明,果径、果形、果色、果味、核形和果实出肉率等性状指标的遗传力较高,说明这些性状变异的遗传贡献较大,可作为白刺果实类型划分的主要指标,其中果径、果味和出肉率可作为白刺果实品质评价和优良亲本选择的主要依据。以果径和出肉率为指标,用家系选择法选择优良亲本可获得较大的遗传增益,且两指标选择的亲本一致,选择效果满意。     

Accumulation in Svalbard glaciers deduced from ice cores with nuclear tests and Chernobyl reference layers

Mean net annual balance and the related spatio-temporal variations have been determined on the basis of well-dated artificial layers in shallow ice cores (Chernobyl, 1986, and atmospheric thermonuclear tests, mainly in 1961-62 in Novaya Zemlya). Seventy ice cores from 13 Svalbard glaciers have been analysed. On each glacier, in its accumulation area and at the highest elevation, one ice core was recovered down to about 40 m and sampled for radioactivity measurements to determine the 1986 and 1962-63 layer (1954 was the initial date of the nuclear tests). For each glacier, at least five complementary ice cores from the accumulation area were analysed to determine the Chernobyl reference layer. Six ice cores exhibit both the Chernobyl and nuclear tests layers and are of special interest in this study.
This work provides new data on the deposition rates of natural and artificial radioisotopes. Using ice cores samples from the Arctic glaciers, even with superimposed ice accumulation, it is possible to distinguish between the Chernobyl and the nuclear tests fallouts. This work also shows that the mean annual net balance did not significantly change for at least five ice core locations in the Svalbard glaciers for the two periods extending from 1963 to 1986 to the recent date of drilling.     

环境场对边界层低空急流形成的影响

本文利用两层流的浅水波模式,讨论了环境场对边界层低空急流形成的影响,并得到了边界层低空急流的特征宽度为L₀=(ρ₂-ρ₁)/(ν₂ρ₂-ρ₁ν₁)L₀*C₀*,式中C₀*=√gh₂, L₀*=C₀*/f为Rossby变形半径,ρ₁,p₂和v₁,v₂分别为上下两层大气的密度和大尺度经向地转风,H₂为低层大气的厚度,g为重力加速度,f为柯氏参数,当高低层大气中的大尺度经向地转风的垂直切变越强时,所形成的中尺度边界层低空急流就越强;当低层大气中的温度增高和湿度增大、并且低层大气中的大尺度经向地转风越强、高度越低时,越有利于形成边界层低空急流。      

VSOP/global VLBI observations of 2021+614: Detection of hotspot advance

We have analysed VSOP and global VLBI data at 5 GHz and VLBA + Effelsberg data at 15 GHz for 2021+614. By identifying the core as being between two bright hotspots, we show that 2021+614 is a compact symmetric object of size 40 pc. From comparison with earlier observations we deduce an apparent age of 375 yr for 2021+614. This provides additional support for the contention that compact symmetric radio objects associated with galaxies are in fact young radio sources and the possible precursors of the classical FR I or FR II radio galaxies.