Antinomies of generosity: Moral geographies and post-tsunami aid in Southeast Asia

The Indian Ocean Tsunami on Boxing Day 2004 generated a wave of private donations from Western countries - a paradigmatic case of generosity. However, more than a year after, a number of evaluation studies conclude that post-tsunami aid has achieved ambivalent results and that recipients of aid felt excluded from the reconstruction process, reduced to passive observers. This paper argues that there is a link between the abundance of generosity and the practices of aid: the practices of gift giving after the tsunami have developed a humiliating force for those who were at the recipient end of the gift chain, because the marketing of Western generosity by media and aid agencies reinforced those affected by the tsunami as “pure” victims, as “bare life” - passive recipients devoid of their status as fellow citizens on this planet. In a second step, the paper discusses the meta-ethics of these practices of generosity, thinking about the ambivalences inherent in bridging distance in encountering the “distant” other in our aid practices. Various forms of virtue ethics reflect this emphasis on the generous person, while neglecting the perspective of the person in need, and therefore implicitly reproduce those asymmetries of gift giving. In contrast to these conceptions, I want to argue that we need to ground our duty to help distant sufferers in their moral entitlement to be aided. This requires a meta-ethical approach that seeks a combination of a theory of justice with virtue ethics.     

Catalysis by mineral surfaces: Implications for Mo geochemistry in anoxic environments

Fixation of Mo in sulfidic environments is believed to be preceded by conversion of geochemically passive MoO₄²⁻ to particle-reactive thiomolybdates (MoO_xS_4−x²⁻). In aqueous solution, these transformations are general-acid catalyzed, implying that proton donors can accelerate both the forward and reverse reactions. Here, we explore whether mineral surfaces also catalyze thiomolybdate interconversions. The rate of MoS₄²⁻ hydrolysis is investigated in the presence and absence of natural kaolinite (KGa-1b) and synthetic Al₂O₃ and SiO₂ phases. Comparison of rates achieved with these phases suggests that the Al oxyhydroxide component in kaolinite furnishes the catalytic activity. An anhydrous Al₂O₃ phase is catalytically inactive until hydrated (and therefore protonated). Surface kinetics with kaolinite at mildly alkaline pH are consistent with rate limitation by formation or decomposition of monomeric surface complexes; oligomeric surface intermediates may become important at MoS₄²⁻ > 20 μmol/L, higher than is likely to be found in nature. The pH dependence of the kaolinite-catalyzed reaction suggests that weak-acid surface sites promote hydrolysis. Intermediate thiomolybdates or molybdate appears to compete for active sites, inhibiting MoS₄²⁻ hydrolysis. Catalysis of MoOS₃²⁻ hydrolysis is also observed but has not been studied systematically. Thiomolybdate hydrolysis is inhibited slightly by sulfate and more strongly by phosphate. Low NaCl concentrations (<10⁻² mol/L) promote hydrolysis, but higher NaCl concentrations retard the reaction to a small extent. A mechanism is postulated involving expansion of the coordination number around Mo from 4 to 6 under the influence of the surface. The effective concentration of surface sites available to Mo in sediment pore waters is likely to be large enough to greatly accelerate thiomolybdate hydrolysis and sulfidation. Possibly this explains why Mo capture in seasonally or intermittently anoxic environments often occurs through processes operating within sediments but not in overlying waters.     

Variation in calcite dissolution rates:: A fundamental problem?

A comparison of published calcite dissolution rates measured far from equilibrium at a pH of ∼ 6 and above shows well over an order of magnitude in variation. Recently published AFM step velocities extend this range further still. In an effort to understand the source of this variation, and to provide additional constraint from a new analytical approach, we have measured dissolution rates by vertical scanning interferometry. In areas of the calcite cleavage surface dominated by etch pits, our measured dissolution rate is 10^−10.95 mol/cm²/s (PCO₂ 10^−3.41 atm, pH 8.82), 5 to ∼100 times slower than published rates derived from bulk powder experiments, although similar to rates derived from AFM step velocities. On cleavage surfaces free of local etch pit development, dissolution is limited by a slow, “global” rate (10^−11.68 mol/cm²/s). Although these differences confirm the importance of etch pit (defect) distribution as a controlling mechanism in calcite dissolution, they also suggest that “bulk” calcite dissolution rates observed in powder experiments may derive substantial enhancement from grain boundaries having high step and kink density. We also observed significant rate inhibition by introduction of dissolved manganese. At 2.0 μM Mn, the rate diminished to 10^−12.4 mol/cm²/s, and the well formed rhombic etch pits that characterized dissolution in pure solution were absent. These results are in good agreement with the pattern of manganese inhibition in published AFM step velocities, assuming a step density on smooth terraces of ∼9 μm⁻¹.     

Comparative Re-Os systematics of chondrites: Implications regarding early solar system processes

A suite of 47 carbonaceous, enstatite, and ordinary chondrites are examined for Re-Os isotopic systematics. There are significant differences in the ¹⁸⁷Re/¹⁸⁸Os and ¹⁸⁷Os/¹⁸⁸Os ratios of carbonaceous chondrites compared with ordinary and enstatite chondrites. The average ¹⁸⁷Re/¹⁸⁸Os for carbonaceous chondrites is 0.392 ± 0.015 (excluding the CK chondrite, Karoonda), compared with 0.422 ± 0.025 and 0.421 ± 0.013 for ordinary and enstatite chondrites (1σ standard deviations). These ratios, recast into elemental Re/Os ratios, are as follows: 0.0814 ± 0.0031, 0.0876 ± 0.0052 and 0.0874 ± 0.0027, respectively. Correspondingly, the ¹⁸⁷Os/¹⁸⁸Os ratios of carbonaceous chondrites average 0.1262 ± 0.0006 (excluding Karoonda), and ordinary and enstatite chondrites average 0.1283 ± 0.0017 and 0.1281 ± 0.0004, respectively (1σ standard deviations). The new results indicate that the Re/Os ratios of meteorites within each group are, in general, quite uniform. The minimal overlap between the isotopic compositions of ordinary and enstatite chondrites vs. carbonaceous chondrites indicates long-term differences in Re/Os for these materials, most likely reflecting chemical fractionation early in solar system history.A majority of the chondrites do not plot within analytical uncertainties of a 4.56-Ga reference isochron. Most of the deviations from the isochron are consistent with minor, relatively recent redistribution of Re and/or Os on a scale of millimeters to centimeters. Some instances of the redistribution may be attributed to terrestrial weathering; others are most likely the result of aqueous alteration or shock events on the parent body within the past 2 Ga.The ¹⁸⁷Os/¹⁸⁸Os ratio of Earth’s primitive upper mantle has been estimated to be 0.1296 ± 8. If this composition was set via addition of a late veneer of planetesimals after core formation, the composition suggests the veneer was dominated by materials that had Re/Os ratios most similar to ordinary and enstatite chondrites.     

Environmental literacy in interpreting endangered sustainability: Case studies from Thailand and the Sudan

This paper examines how people explain reasons and impacts of environmental change in the low-rain savanna of the central Sudan and mountainous forest lands of northern Thailand. The explanations are analyzed by using the concept of environmental literacy, which refers to the people’s ability to grasp the environment and its interactions. The paper aims to study people’s conceptions of the environment, which compose one factor in directing their behavior. For the study, rural inhabitants in the State of North Kordofan, the Sudan, and the Chiang Mai Province in Thailand were interviewed.It was noted that an individual’s capability to understand the environment is alone insufficient to address environmental problems because the efficient alleviation of the problems requires collective actions at all levels, and because of factors beyond an individual’s control. However, the results supported the assumption that the local people have knowledge of their environment that may help in developing sustainable environmental management practices. The main advantages of using the environmental literacy concept are argued to be its dynamic and synthetic essence, its link to sustainable behavior, and wide applicability in various contexts within heterogeneous communities.     

Diagenesis and geochemistry of porites corals from Papua New Guinea: Implications for paleoclimate reconstruction

Coral proxy records of sea surface temperature (SST) and hydrological balance have become important tools in the field of tropical paleoclimatology. However, coral aragonite is subject to post-depositional diagenetic alteration in both the marine and vadose environments. To understand the impact of diagenesis on coral climate proxies, two mid-Holocene Porites corals from raised reefs on Muschu Island, Papua New Guinea, were analysed for Sr/Ca, δ¹⁸O, and δ¹³C along transects from 100% aragonite to 100% calcite. Thin-section analysis showed a characteristic vadose zone diagenetic sequence, beginning with leaching of primary aragonite and fine calcite overgrowths, transitional to calcite void filling and neomorphic, fabric selective replacement of the coral skeleton. Average calcite Sr/Ca and δ¹⁸O values were lower than those for coral aragonite, decreasing from 0.0088 to 0.0021 and −5.2 to −8.1‰, respectively. The relatively low Sr/Ca of the secondary calcite reflects the Sr/Ca of dissolving phases and the large difference between aragonite and calcite Sr/Ca partition coefficients. The decrease in δ¹⁸O of calcite relative to coral aragonite is a function of the δ¹⁸O of precipitation. Carbon-isotope ratios in secondary calcite are variable, though generally lower relative to aragonite, ranging from −2.5 to −10.4%. The variability of δ¹³C in secondary calcite reflects the amount of soil CO₂ contributing ¹³C-depleted carbon to the precipitating fluids. Diagenesis has a greater impact on Sr/Ca than on δ¹⁸O; the calcite compositions reported here convert to SST anomalies of 115°C and 14°C, respectively. Based on calcite Sr/Ca compositions in this study and in the literature, the sensitivity of coral Sr/Ca-SST to vadose-zone calcite diagenesis is 1.1 to 1.5°C per percent calcite. In contrast, the rate of change in coral δ¹⁸O-SST is relatively small (−0.2 to 0.2°C per percent calcite). We show that large shifts in δ¹⁸O, reported for mid-Holocene and Last Interglacial corals with warmer than present Sr/Ca-SSTs, cannot be caused by calcite diagenesis. Low-level calcite diagenesis can be detected through X-ray diffraction techniques, thin section analysis, and high spatial resolution sampling of the coral skeleton and thus should not impede the production of accurate coral paleoclimate reconstructions.     

Main-group pallasites: chemical composition, relationship to IIIAB irons, and origin

We used neutron activation to characterize the metal of 33 main-group pallasites (PMG), widely held to be samples of a core-mantle interface. Most PMG cluster in a narrow range of metal and silicate compositions, but 6 are assigned to an anomalous subset (PMG-am) because of their deviant metal compositions, and 4 others to another anomalous subset (PMG-as) because of their appreciably higher olivine Fa contents. Metal compositions in all PMG are closely related to those in evolved IIIAB irons, and are generally consistent with their formation in the IIIAB parent asteroid. On element-Au diagrams for incompatible elements the normal PMG plot near an extrapolation of IIIAB trends to higher Au concentrations. On element-Au plots of compatible elements such as Ir or Pt the loci of PMG spread out over a broader region explainable by mixing of evolved IIIAB magma with early-crystallized core or mantle-residue solids.Two features of PMG require special models: (1) Ga and Ge contents are generally high (≈1.5×) compared to the IIIAB-based mixing model: and (2) the FeO/(FeO + MgO) ratios span a surprisingly wide range, from 0.11-0.14 in normal PMG to 0.16 to 0.18 in PMG-as This range is larger than expected in a cumulate layer at the base of a mantle. We suggest that both features may be related to the interaction of PMG precursors with a highly evolved magmatic gas phase, and that some or all of these anomalies may have resulted from vapor deposits in voids near the core-mantle interface.An important boundary condition for understanding the detailed PMG origin at the core-mantle interface is the large difference between the solidus temperature of Fa11 olivine (≈2000 K) and the liquidus temperature of an evolved IIIAB melt containing >100 mg/g S and some P (≈1600 K). Following the mixing event that formed the PMG it is therefore reasonable that there would have been olivine rubble floating on top of the IIIAB-like magma, but with appreciable void space present just above the upper level reached by the magma. These voids would have contained gases released from the magma during its flow into the PMG region. We suggest that Ga and Ge, the two most volatile siderophiles in our element set, were added to PMG metal from the magmatic gas. We also suggest that the magmatic gas was oxidizing and that the PMG having high olivine fayalite contents formed in regions where the ratio of void to olivine was high, and that some metallic Fe was oxidized and entered the olivine (or the phosphoran olivine). In support of the latter idea is the observation that both Ni and Co are elevated in the PMG-as (Fa≥16) compared to values predicted by IIIAB trends.We analyzed two Eagle-Station pallasites (PES); after correction for weathering effects in Cold Bay, its composition is found to closely resemble that of Eagle Station but to represent a more evolved composition (i.e., lower Ir, higher Au). Vermillion and Yamato 8451 have been called pyroxene pallasites but have metal compositions (unrelated to those of the PMG or PES) that are too different from each other to even allow assignment to the same grouplet.     

An anisotropic Model for Structured Soils: Part I: Theory

The paper presents an incremental plasticity constitutive Model for Structured Soils (MSS–2) to describe the effects of structure (stress history and bonding) on the mechanical behaviour of cohesive soils. Such effects are high initial stiffness, dilatancy and peak strength, their appreciable reduction upon strain-induced de-structuring and the evolution of material anisotropy. The proposed model advances present practice in incremental elasto-plasticity for structured soils by incorporating: (a) distorted ellipsoids, rotated with respect to the isotropic axis, for the Structure Strength Envelope (bounding surface) and the Plastic Yield Envelope (yield surface) to describe the evolution of structure and anisotropy, (b) an Intrinsic Compressibility Framework and a corresponding Intrinsic Strength Envelope which represents a lower bound of the Structure Strength Envelope and is used as reference locus for the structureless material, (c) an improved damage mechanism to model structure degradation by plastic strains and (d) a non-associated flow rule controlled by structure. The proposed model is modular, its features can be activated simultaneously or selectively, and the 3-D tensorial formulation facilitates direct implementation in finite elements codes.     

Microscopic reversibility of Sm and Yb sorption onto smectite and kaolinite: Experimental evidence

The microscopic reversibility of the sorption of Sm and Yb onto kaolinite and smectite is investigated by introducing an isotopic disequilibrium between the clay and the solution. The experiments are performed at 25°C, in 0.025 or 0.5 M NaClO₄ and from pH 4 up to pH 7. The isotopic exchange is monitored as a function of time over a duration of 355 hours. The first stage of the experiment consists of equilibrating the clays with a natural or spiked lanthanide solution. The second stage consists of interchanging the solutions between twin phials (same clay, pH and ionic strength, but with different lanthanide isotopic compositions). The isotopic composition and concentration of aqueous lanthanides are analysed by ICP-MS. The results are as follows: (1) the lanthanide isotopic composition of the solution is rapidly modified and stabilised within 24 h; (2) the isotopic exchange between the solid and the solution is not always complete; (3) the degree of microscopic reversibility (isotopic exchange) decreases with increasing pH. These results are explained by the fact that exchange is easier for lanthanides linked to the surface as outer-sphere complexes (physical sorption), which predominate at low pH, than for atoms sorbed as inner-sphere complexes (chemical sorption) which predominate at high pH. The contrasted kinetics observed for the different kind of sites provide additional constraints for the modeling of migration processes in natural systems.     

Polytype distribution of circumstellar silicon carbide: microstructural characterization by transmission electron microscopy

Silicon carbide (SiC) is a particularly interesting species of presolar grain because it is known to form on the order of a hundred different polytypes in the laboratory, and the formation of a particular polytype is sensitive to growth conditions. Astronomical evidence for the formation of SiC in expanding circumstellar atmospheres of asymptotic giant branch (AGB) carbon stars is provided by infrared (IR) studies. However, identification of the crystallographic structure of SiC from IR spectra is controversial. Since >95% of the presolar SiC isolated from meteorites formed around carbon stars, a determination of the structure of presolar SiC is, to first order, a direct determination of the structure of circumstellar SiC. We therefore determined the polytype distribution of presolar SiC from the Murchison CM2 carbonaceous meteorite using analytical and high-resolution transmission electron microscopy (TEM). High-resolution lattice images and electron diffraction of 508 individual SiC grains demonstrate that only two polytypes are present, the cubic 3C (β-SiC) polytype (79.4% of population by number) and the hexagonal 2H (α-SiC) polytype (2.7%). Intergrowths of these two polytypes are relatively abundant (17.1%). No other polytypes were found. A small population of one-dimensionally disordered SiC grains (0.9%), whose high density of stacking faults precluded classification as any polytype, was also observed. The presolar origin of 2H α-SiC is unambiguously established by tens-of-nanometers-resolution secondary ion mass spectroscopy (NanoSIMS). Isotopic maps of a TEM-characterized 2H α-SiC grain exhibit non-solar isotopic compositions of ¹²C/¹³C = 64 ± 4 and ¹⁴N/¹⁵N = 575 ± 24. These measurements are consistent with mainstream presolar SiC thought to originate in the expanding atmospheres of AGB carbon stars. Equilibrium condensation calculations together with inferred mineral condensation sequences predict relatively low SiC condensation temperatures in carbon stars. The laboratory observed condensation temperatures of 2H and 3C SiC are generally the lowest of all SiC polytypes and fall within the predictions of the equilibrium calculations. These points account for the occurrence of only 2H and 3C polytypes of SiC in circumstellar outflows. The 2H and 3C SiC polytypes presumably condense at different radii (i.e., temperatures) in the expanding stellar atmospheres of AGB carbon stars.     

Laser combustion analysis of δS of sulfosalt minerals: determination of the fractionation systematics and some crystal-chemical considerations

Laser sulfur combustion in the presence of O₂ is the most commonly used method of in situ sulfur isotope analysis. Previous workers indicated that a small but reproducible fractionation of ³⁴S/³²S exists between the product SO₂ gas and the mineral. The magnitude of this fractionation varies with bond strength, as reflected in Gibbs free energy of formation at 298.15K. The correction factors are known for common sulfides and anhydrite but not, hitherto, for stibnite and the sulfosalt minerals, which are important constituents of many classes of ore deposits. We present the correction factors for the following chemically and crystallographically well-characterized minerals: stibnite (weighted mean = −1.2‰), bournonite (+0.6‰), tetrahedrite (+1.3‰), and boulangerite (+1.4‰). The Gibbs free energies of formation of these phases have been approximated by the sulfide summation method, and the correlation of ΔG₂₉₈⁰ with the correction factor for the sulfosalts fits well with the trend previously established for simple sulfides. There is an excellent correlation between the fractionation factor and mineral composition, a parameter that does result in bond strength variations (e.g., mol fraction of PbS in sulfosalts), allowing estimation of the correction factors for simple intermediate compositions. Finally, bond strength also varies with variation in interatomic distances, and we have, therefore, investigated the behaviour of stibnite, a strongly anisotropic mineral. Our results indicate that there is a significant variation in fractionation factor, depending on crystal orientation. The fractionation factor along the prismatic b-axis, which displays the strongest chemical bonds (as monitored by the shortest bond lengths), is more negative (−1.7‰) than along the other crystallographic directions (−0.7 to −1.0‰), which is in full agreement with theoretical predictions. We demonstrate the application of the technique in unravelling source- and process-related sulfur isotope systematics in two hydrothermal vein systems in the classic mining area of the NE Rhenish Massif, both studies requiring resolution beyond the scale of conventional sulfur isotope analysis.     

Water dissolution in albite melts:: Constraints from ab initio NMR calculations

Hartree-Fock and B3LYP NMR calculations were performed at the 6-311+G(2df,p) level on cluster models representing albite glasses using B3LYP/6 to 31G* optimized geometries. Calculation results on several well-known crystalline materials, such as low albite and KHSi₂O_5, were used to check the accuracy of the calculation methods.Calculated ²⁹Si-NMR results on clusters that model protonation of Al-O-Si linkages and the replacement of Na⁺ by H⁺ indicate a major increase in Si-O(H) bond length and a 5 ppm difference in δ_iso for ²⁹Si compared to that for anhydrous albite glass. The calculated δ_iso of ²⁷Al in such linkages agrees with the experimental data, but shows an increase in C_q that cannot be fully diminished by H-bonding to additional water molecules. This protonation model is consistent with both experimental ¹⁷O NMR data and the major peak of ¹H-NMR spectra. It cannot readily explain the existence of the small peak in the experimental ¹H spectra around 1.5 ppm. Production of the depolymerized units Al [Q³]-O-H upon the dissolution of water is not consistent with ²⁷Al, ¹H, or ¹⁷O NMR experimental results. Production of Si [Q³]-O-H is consistent with all of the experimental ¹⁷O and ¹H-NMR data; such units can produce both the major peak at 3.5 ppm and the small peak at 1.5 ppm in ¹H spectra, either with or without hydrogen bonding. This species, however, cannot produce the main features of ²⁹Si spectra.It is concluded that although neither protonation nor the production of Si [Q³]-O-H alone is consistent with the available experimental data, the combination of these two processes is consistent with available experimental NMR data.     

The state and the regulation of biodiversity: International biopolitics and the case of Mexico

In this article, the evolving forms of biodiversity politics are examined in the light of regulation theory and in the tradition of materialistic state theory (Gramsci, Poulantzas, etc.). Biodiversity politics is not so much oriented toward the conservation of biodiversity as towards the creation of a stable political-institutional framework for its commercialization. In this contested and contradictory process, the nation state plays a crucial role. After a few remarks on the theoretical assumptions, some basic elements of the international regulation system of genetic resources are presented. The main topics of international biodiversity politics beside conservation are: access to biodiversity and its genetic resources, benefit sharing from its use and intellectual property rights. A major problem of this system is the relationship between varying negotiation processes in different fora. Another closely connected problem is the contradictory relationship between different regulatory levels at different spatial scales (international, regional, local). These contradictions are analyzed for the case of Mexico. Central issues of Mexican biodiversity politics, and the different actors, forces and interests are outlined and discussed against our initial theoretical reflections. Bioprospecting projects in the south of Mexico have raised questions of legal and legitimate forms of access, which have generated growing concern and significant disputes within Mexico. Finally, some conclusions are drawn, binding together the theoretical with the empirical results of our study.     

Comparative geochemistries of Pd and Pt:: Formation of mixed hydroxychloro and chlorocarbonato-complexes in seawater

Comparative observations of Pd^II and Pt^II hydrolysis in chloride solutions indicate that [PdCl₃OH²⁻]/[PdCl42−] and [PtCl₃OH²⁻]/[PtCl42−] concentration ratios in salinity 35 seawater (S = 35) are smaller than one at a typical surface ocean pH (∼8.2), and are larger than one at pH = 8.2 when S < 10. The hydrolysis behaviors of PdCl42− and PtCl42− are very similar. In 0.5 M NaCl at 25°C the hydrolysis constant for both elements, written in the form β₁ = [MCl₃OH²⁻][Cl⁻][H⁺][MCl42−]⁻¹, is logβ1*=−8.97. Between ionic strengths 0.3 M and 1.0 M for Pd^II and between 0.1 M and 1.0 M for Pt^II, log β₁ is within approximately 0.1 units of the value appropriate to 0.5 M NaCl. This small dependence of PdCl42− and PtCl42− hydrolysis constants on ionic strength is consistent with predictions based on expected activity coefficient behavior.Carbonate is observed to complex PdCl42− significantly, but to a smaller extent than OH⁻ under conditions appropriate to seawater. Complexation of PtCl42− by CO32− was observed in this work but the rate of complexation was too slow to allow equilibrium observations. The principal dissimilarity between the chemistries of Pd^II and Pt^II in our investigation was the sharp contrast in observed Pd^II and Pt^II reaction rates. Differences in reaction kinetics may cause fractionation of Pd^II and Pt^II in the environment. The speciation of Pt^II, unlike Pd^II, is likely to be based on chemical environments experienced by Pt^II over a period of days, and perhaps weeks.