The geography of multiple scarcities: Urban development and water problems in Lima,Peru

The paper discusses the contradictory evolution of water services and the politicised nature of water scarcity in Lima, the capital of Peru. It initially claims that water scarcity cannot be understood as an isolated phenomenon, but it is inserted in a wider multiplicity of scarcities that characterise contemporary urban development. The naturalisation of scarcity in the official policy discourse is then criticised for its tendency to overlook interconnected mechanisms of political differentiation and socioeconomic exploitation that influence the allocation and use of water. Against such reductionist readings, the analysis employs a non-essentialist interpretation of multiple scarcities related to water and emphasises the need to address the totality of the experience of scarcity. Based on qualitative fieldwork, which explored recent institutional reforms and the daily struggle for water in the periphery of Lima, three fundamental reasons were identified for the persistence of water scarcity: first, the expansion of water problems as a result of the poor quality of housing and the discriminatory practices against low-income residents; second, the modest improvements in water services provided by public investment programmes, which have primarily aimed to answer political and electoral demands of the ruling party; and third, the technocratic basis of new management approaches and the systematic exclusion of grassroots communities from the decision-making process. Genuine responses to the mounting water problems of Lima require a more critical appreciation of the production of circumstantial abundances and totalising scarcities in the city.     

Granulite-amphibolite facies metasediments from the Serre (Calabria,Southern Italy): their protoliths and the processes controlling their chemistry

In the northwestern Serre, a near continuous section through the Palaeozoic lower continental crust crops out. This paper deals with granulite facies metasedimentary rocks of this section. Fifty-five chemical analyses (major elements, Sc, V, Cr, Co, Ni, Rb, Sr, Y, Nb and Ba) are given. Chemical data indicate that the original sedimentary sequence was made up of arenites in the lower part and mainly Fe and Mg rich pelites in the upper part. The metapelites experienced anatexis and removal of some melt, whereas the meta-arenites suffered only incipient anatexis and became dehydration granulites. The various rock types display an overall relatively low K/Rb ratio due mainly to the stability of K- and Rb-retaining phases. A weighted mean composition of the fragment of the lower continental crust outcropping in the Serre has been established by integrating the chemical data for metasediments (55 analyses), metabasites (92 analyses) and dioritic and tonalitic gneisses (10 analyses) with the field data. This composition compared to the compositions of the bulk continental crust and of other sections considered as belonging to the lower crust, confirms the hypothesis that (1) the lower crust is heterogeneous, and (2) it is more basic than the continental crust.     

Association of subsurface radon changes in Alaska and the northeastern United States with earthquakes

Changes of radon concentration in the ground have been reported to correlate with seismic activity in many places over widely varying distances from the earthquake epicenters, sometimes over 100's and occasionally over 1000's of km depending on the magnitude M of the earthquakes. For proper use of such correlations in forecasting the location and size of impending earthquakes, it would be useful to establish a relation between M and the maximum distance x_M at which radon can be significantly altered by preseismic effects.We have monitored radon in the ground continuously at Blue Mountain Lake, NY starting Dec. 3. 1975 and at three locations in Alaska—Icy Bay, Yakataga, and Sand Point (starting Nov. 12, 1979; March 5, 1980; and June 29, 1980 respectively). Sample correlations from visual examination of the recent radon record and tentative use of a proposed scaling relation show a number of possible earthquake-related signals at these locations. The data are compatible with scaling relations that were derived from two separate models of premonitory elastic strains. In this work x_M = 10^0.48M, where x_M is in units of km and M ≥ 3. Since tilt and strain signals correlate similarly with magnitude and distance, it is likely that most earthquake-related radon signals are mechanically induced.     

9000 years of changes in peat organic matter composition in Store Mosse (Sweden) traced using FTIR-ATR

Store Mosse (the ‘Great Bog’ in Swedish) is one of the most extensive bog complexes in southern Sweden (~77 km²), where pioneering palaeoenvironmental research has been carried out since the early 20th century. This includes, for example, vegetation changes, carbon and nitrogen dynamics, peat decomposition, atmospheric metal pollution, mineral dust deposition, dendrochronology, and tephrochronology. Even though organic matter (OM) represents the bulk of the peat mass and its compositional change has the potential to provide crucial ecological information on bog responses to environmental factors, peat OM molecular composition has not been addressed in detail. Here, a 568-cm-deep peat sequence was studied at high resolution, by attenuated reflectance Fourier-transform infrared spectroscopy (FTIR-ATR) in the mid-infrared region (4000–400 cm^–1). Principal components analysis was performed on selected absorbances and change-point modelling was applied to the records to determine the timing of changes. Four components accounted for peat composition: (i) depletion/accumulation of labile (i.e. carbohydrates) and recalcitrant (i.e. lignin and other aromatics, aliphatics, organic acids and some N compounds) compounds, due to peat decomposition; (ii) variations in N compounds and carbohydrates; (iii) residual variation of lignin and organic acids; and (iv) residual variation of aliphatic structures. Peat decomposition showed two main patterns: a long-term trend highly correlated to peat age (r = 0.87), and a short-term trend, which showed five main phases of increased decomposition (at ~8.4–8.1, ~7.0–5.6, ~3.5–3.1, ~2.7–2.1 and ~1.6–1.3 ka) – mostly corresponding to drier climate and its effect on bog hydrology. The high peat accumulation event (~5.6–3.9 ka), described in earlier studies, is characterized by the lowest degree of peat decomposition of the whole record. Given that FTIR-ATR is a quick, non-destructive, cost-effective technique, our results indicate that it can be applied in a systematic way (including multicore studies) to peat research and provide relevant information on the evolution of peatlands.     

Is Prediction of Future Landslides Possible with a GIS?

This contribution explores a strategy for landslide hazard zonation inwhich layers of spatial data are used to represent typical settings inwhich given dynamic types of landslides are likely to occur. Theconcepts of assessment and prediction are defined to focus on therepresentation of future hazardous events and in particular on themyths that often provide obstacles in the application of quantitativemethods. The prediction rate curves for different applications describethe support provided by the different data layers in experiments inwhich the typical setting of hazardous events is approximated bystatistically integrating the spatial information.     

Crystallization conditions of Los Angeles, a basaltic Martian meteorite

The texture of Los Angeles (stone 1) is dominated by relatively large (0.5−2.0 mm) anhedral to subhedral grains of pyroxene, and generally subhedral to euhedral shocked plagioclase feldspar (maskelynite). Minor phases include subhedral titanomagnetite and ilmenite, Fe-rich olivine, olivine+augite-dominated symplectites [some of which include a Si-rich phase and some which do not], pyrrhotite, phosphate(s), and an impact shock-related alkali- and silica-rich glass closely associated with anhedral to euhedral silica grains. Observations and model calculations indicate that the initial crystallization of Mg-rich pigeonitic pyroxenes at ≤1150 °C, probably concomitantly with plagioclase, was followed by pigeonitic and augitic compositions between 1100 and 1050 °C whereas between 1050 and 920 to 905 °C pyroxene of single composition crystallized. Below 920 to 905 °C, single composition Fe-rich clinopyroxene exsolved to augite and pigeonite. Initial appearance of titanomagnetite probably occurred near 990 °C and FMQ-1.5 whereas at and below 990 °C and ≥FMQ-1.5 titanomagnetite and single composition Fe-rich clinopyroxene may have started to react, producing ilmenite and olivine. However, judging from the most common titanomagnetite compositions, we infer that most of this reaction likely occurred between 950 and 900 °C at FMQ-1.0±0.2 and nearly simultaneously with pyroxene exsolution, thus producing assemblages of pigeonite, titanomagnetite, olivine, ilmenite, and augite. We deem this reaction as the most plausible explanation for the formation of the olivine+augite-dominated symplectites in Los Angeles. But we cannot preclude possible contributions to the symplectites from the shock-related alkali- and silica-rich glass or shocked plagioclase, and the breakdown of Fe-rich pigeonite compositions to olivine+augite+silica below 900 °C. Reactions between Fe-Ti oxides and silicate minerals in Los Angeles and other similar basaltic Martian meteorites can control the T-fO₂ equilibration path during cooling, which may better explain the relative differences in fO₂ among the basaltic Martian meteorites.     

Hydrogeological research on intensively exploited deep aquifers in the ‘Loma de Úbeda’ area (Jaén, southern Spain)

The intensive use of groundwater for irrigation in the area of Úbeda (‘Loma de Úbeda’, Jaén, southern Spain) has transformed an area of traditionally rain-fed dry farmland into fields with some of the highest olive oil productivity in the world. Early hydrogeological research studies, initiated just after the beginning of the groundwater exploitation, revealed that the water was collected from three different overlapping aquifers occupying an area of over 1,100 km², with the lower aquifers located at depths from 300 to over 700 m in an area of 440 km². Multidisciplinary research, based on geological characterization, and piezometric, hydrochemical and isotopic data, has led to a conceptual model of functioning in this complex hydrogeological system. The proposed model allows for the identification of the recharge areas, and the discharge, which is at present mainly associated with the groundwater pumping. Areas of mixing of waters from the different aquifers and the main hydrogeochemical processes affecting groundwater quality are described.     

Late-glacial to Holocene transition in northern Spain deduced from land-snail shelly accumulations

Shells of the helicid Cepaea nemoralis were studied using taphonomic, isotopic and morphometric measurements to estimate late glacial–Holocene (~ 12.1–6.3 cal ka BP) environmental conditions in northern Spain. Higher taphonomic alteration among Holocene shells suggests lower sedimentation rates or higher shell-destruction rates than during glacial conditions. Shells preserved the aragonitic composition despite differing degree of skeleton damage. Shell δ¹³C values were ? 10.3 ± 1.1‰, ? 8.2 ± 2.3‰, and ? 7.3 ± 1.6‰ for modern, Holocene and late-glacial individuals, respectively. Higher δ¹³C values during the late-glacial and some Holocene periods imply higher water stress of C₃ plants and/or higher limestone contribution than today. Intrashell δ¹³C values were higher during juvenile stages suggesting higher limestone ingestion to promote shell growth. Shell δ¹⁸O values were ? 1.1 ± 0.7‰, ? 0.9 ± 0.8‰ and ? 0.1 ± 0.7‰ for modern, Holocene and late-glacial specimens, respectively. A snail flux-balance model suggests that during ~ 12.1 ? 10.9 cal ka BP conditions were drier and became wetter at ~ 8.4 ? 6.3 cal ka BP and today. Intrashell δ¹⁸O profiles reveal that glacial individuals experienced more extreme seasonality than interglacial shells, despite possible larger hibernation periods. Shell size correlated positively with δ¹⁸O values, suggesting that growth rates and ultimate adult size of C. nemoralis may respond to climate fluctuation in northern Spain.     

An adjoint-based optimization method for gas production in shale reservoirs

In this work, we consider a new model for flow in a multiporosity shale gas reservoir constructed within the framework of an upscaling procedure where hydraulic fractures are treated as (\(n-1\)) interfaces (\(n=2,3\)). Within this framework, the hydrodynamics is governed by a new pressure equation in the shale matrix which is treated as a homogenized porous medium composed of organic matter (kerogen aggregates with nanopores) and inorganic impermeable solid (clay, calcite, quartz) separated from each other by a network of interparticle pores of micrometer size. The solution of the pressure equation is strongly influenced by the constitutive response of the retardation parameter and effective hydraulic conductivity where the former incorporates gas adsorption/desorption in the nanopores of the kerogen. By focusing our analyses on this nonlinear diffusion equation in the domain occupied by the shale matrix, an optimization strategy seated on the adjoint sensitivity method is developed to minimize a cost functional related to gas production and net present value in a single hydraulic fracture. The gradient of the objective functional computed with the adjoint formulation is explored to update the controlled pressure drop aiming to optimize production in a given window of time. The combination of the direct approach and gradient-based optimization using the adjoint formulation leads to the construction of optimal production scenarios under controlled pressure decline in the well. Numerical simulations illustrate the potential of the methodology proposed herein in optimizing gas production.