“Invisible women" Making the case for supply-led,class-based,gender targeted land redistribution in South Africa

Despite progressive policies and guidelines to ensure gender equity in the South African land reform programme, the achievement to date is less impressive. In agreement with others we view gender related challenges in the land reform programme as the result of (1) inconsistent interpretations of gender equity and (2) uncertainty on how women specifically should be targeted in the land reform programme. The paper proposes to promote gender equity by introducing of a supply-led strategy with class sensitive gender targets within the land redistribution component of the land reform programme. This revised version was published online in July 2006 with corrections to the Cover Date.     

On Analysis of Dual Spacecraft Stereoscopic Observations to Determine the Three-Dimensional Morphology and Plasma Properties of Solar Coronal Flux Tubes

By using two spacecraft equipped with multi-bandpass X-ray telescopes, it is possible to obtain direct 3-dimensional morphology of coronal structures which is essential for understanding the energetics and dynamics of the solar atmosphere. X-ray observations taken only in orbit about the Earth are inadequate to fully resolve the 3-dimensional nature of the solar corona. These Earth-orbit observations produce 2-dimensional images and an appropriate model must be included to derive the 3-dimensional structures from the line-of-sight information. Stereoscopic observations from space will remove this limitation and are needed if we are to improve our knowledge of the 3-dimensional morphology of the corona.Several important points regarding a stereoscopic mission are investigated and illustrated using model coronal flux tubes and image-rendering techniques. Synthesized images are formed by integrating the emission from volume elements along the line-of-sight path through a 3-dimensional volume in which a set of model flux tubes are located. The flux tubes are defined by (1) a plasma model defining the emissivity for a specific density, temperature, and pressure distribution, and (2) a magnetic field model from which a set of field lines are selected to define the geometry of the flux tubes. The field lines are used to define the flux-tube volume by assuming an initial base radius and conservation of flux. An effective instrumental spectral-response function is folded into the integration. Analysis of pairs of these synthesized images with various angular perspectives are used to investigate the effect of angular separation on mission objectives. The resulting images and analysis provide guidelines for developing a stereoscopic mission.Our study produced four important results, namely: (1) An angular separation of 30 degrees maximizes the scientific return by direct triangulation analysis because of the tradeoff between increased line-of-sight resolution of position and decreased recognition of individual loop structures arising from the overlapping of multiple loops with increasing angular separation. (2) The analysis benefits from the use of time-differential images to select flux tubes from the collection of numerous overlapping systems by selecting only recently heated or cooled flux tubes. (3) An analysis needs to be developed for algebraic reconstruction techniques applying a priori information, specific to the solar coronal structures, i.e., flux-tube continuity, maximum emission strength, non-negative emission, previous history, and maximum gradients of emission. (4) An analysis strategy combining triangulation, modeling techniques, and algebraic restoration is necessary to derive a complete understanding of the 3-dimensional morphology of the magnetic field. In the same way that helioseismology is classical viewing of the Sun with a tailored set of analysis tools for probing the interior of the Sun, heliostereoscopy is classical viewing of the X-ray emitting corona and requires a tailored set of analysis tools to deduce the true 3-dimensional structure of the corona.     

Tertiary and Quaternary vegetation history of the Great Salt Lake, Utah, USA

Pollen analysis of 5 wells drilled to bedrock in the Great Salt Lake, Utah, USA provide a record vegetation change over the last ca 13.5 Ma. Over 440 pollen samples have been counted. The longest record presented is for the mid-lake Bridge Well. Close-interval (3–10 Ka) sampling is presented for the upper Indian Cove well. Chronologic control is provided by identification volcanic tephra and by K/Ar, Ar/Ar, and fission-track dates. Ash determinations are based on electron microprobe analyses of iron, calcium, and other elements compared to Neogene ash data at the University of Utah. Sedimentation begins 38 Ma, with good pollen preservation is sediments younger than 13.5 Ma, and no obvious gaps in sedimentation after 6 Ma.The upland vegetation is desert from the late Miocene onward, with Sarcobatus and Ephedra pollen dominance during the late Miocene (<5 Ma). Chenopodiaceae-Amaranthus, and Artemisia gain dominance during the Pliocene (5–2.5 Ma) and early Pleistocene. Pinus and Artemisia sharply increase in the late Pleistocene (0.75 Ma). The pollen of 'Tertiary exotics' (elm, hickory, Ostrya-Carpinus) is rare, but persists into the Pleistocene. Major vegetation – climatic events occur 3.7 and 2.5 Ma. Increased pollen concentration and sedimentation rate after 310 Ka are attributed to the diversion of the Bear River into the Bonneville Basin.Glacial-interglacial cycles appear as alternations of Chenopodiaceae-Amaranthus (interglacial) vs Artemisia (glacial) during the Pliocene and early Pleistocene, and of Cupressaceae, Sarcobatus, and Gramineae (interglacial) vs Picea, Abies, and Pseudotsuga (glacial) during the late Pleistocene. Pluvial cycles are separated by interpluvial peaks in percentages of wetground and aquatic types. Six interpluvials are indicated during the last 759 Ka, with pluvial cycles of ca 100 Ka cyclicity back to 1.5 Ma.     

Geochemical evolution of peraluminous plutons in southern Nova Scotia, Canada—a pegmatite-poor suite

Three southern Nova Scotia plutons crystallized rapidly at 375 Ma from magma containing both mantle and crustal components. Isotopic and chemical data suggest that the crustal contribution included both lower crustal material and Cambro-Ordovician turbidites of the host Meguma Group. Despite local evidence of mixing and mingling of magmas, the bulk of the plutons evolved by assimilation and fractional crystallisation. Evolved portions of the plutons have compositions appropriate for development of rare-metal pegmatite fields, but pegmatites are relatively rare and little differentiated. Like parental plutons, pegmatites fall into biotite+plagioclase and muscovite+potassium feldspar assemblages. The latter locally contain Mn-rich garnet+biotite, giving calculated P–T conditions of pegmatite crystallisation of 620°C, 0.44 GPa under water-saturated conditions. Host rocks at the time of emplacement experienced P–T conditions varying from <500° to 620°C at 0.44 GPa. Beryl-bearing pegmatites occur only where host rocks were below sillimanite-grade, and pegmatites of any kind are scarce in sillimanite-grade host rocks. Rarity of pegmatites can be ascribed to a combination of insufficient amounts of F, Li, and B in the magma with rapid cooling which prevented extensive fractionation and undercooling. Our data suggest rather that peraluminous suites, produced by rapid heating due to incursions of lithospheric mantle into supracrustal rocks, and typified by biotite-rich, cordierite-bearing plutons, are not favorable locales for major rare-metal-enriched pegmatite fields. Such fields appear to require relatively prolonged anatexis resulting from crustal thickening, or an areally extensive mafic underplate,     

Laboratory Column Experiments Using Polymer Mats to Remove Selected VOCs, PAHs, and Pesticides from Ground Water

Large-scale column experiments were undertaken to evaluate the potential of polymer mats to remove selected volatile organic compounds, polycyclic aromatic hydrocarbons, and pesticides (atrazine and fenamiphos) from ground water and potentially to act as permeable reactive barriers in contaminated ground water environments. The polymer mats, composed of interwoven silicone (dimethylsiloxane) tubes and purged with air, were installed in 2 m long flow-through columns. The polymer mats proved efficient in physically removing (stripping) benzene and naphthalene from contaminated water. Removal efficiencies for both these compounds from an aqueous phase flowing past a polymer mat were 75% or greater. However, for atrazine and fenamiphos, removal efficiencies were 5% or less, probably as a result of their lower Henry's law constants and possibly lower polymer diffusion coefficients.
These experiments indicate that, at least for relatively volatile compounds, polymer mats can provide a remediation technique for the removal of organic compounds from contaminated water. Application of this technique may be well suited as a longer-term, semipassive strategy to remediate contaminated ground water, using natural ground water flow to deliver contaminated ground water to polymer mats engineered as sorption-stripping barriers.
Additional benefits of this technique may include targeted delivery of gaseous chemical amendments, such as oxygen, to enhance aerobic biodegradation and to further reduce any residual concentrations of contaminants.     

The use of multi-electrode resistivity imaging in gravel prospecting

We investigated the potential of using a 24-electrode resistivity imaging apparatus for rapid reconnaissance surveys for natural-aggregate accumulation. The surveys were first calibrated at sites with known geometry of sand and gravel layers, which showed that subsurface accumulation of coarse material was accurately resolved with both 2- and 4-m electrode spacing. The inverted absolute resistivity of economically viable gravel deposits varied in the range of 300–1500 Ω m, depending on variation in ground-moisture levels. The exploration surveys were then conducted at seven sites where geomorphological analyses indicated a potential for gravel. Four of these sites, where subsurface resistivity did not exceed 30–40 Ω m, were found to have very little or no coarse material. The three remaining sites showed significant accumulations of high-resistivity material, two of which were subsequently augered for verification. The results of drilling demonstrated that resistivity images were an effective indicator of the presence of coarse material in the subsurface, allowing accurate determination of subsurface distribution and thickness of sand and gravel strata. The total volume of a deposit could easily be estimated from resistivity images. The absolute quality and economic value of the material, is, however, difficult to ascertain from resistivity images alone without drilling.     

Paleomagnetic study at a nuclear power plant site near Bakersfield, California

At the San Joaquin plant site near Bakersfield, California, the Brunhes/Matuyama reversal was identified 4 m below an ash probably correlative with the Bishop Tuff. Deposition of coarse detritus in a high-energy environment preceded the reversal, whereas a low-energy lake and back-swamp type sedimentation persisted through most of the interval, separating the reversal and the ash. Sediments below the reversal are strongly remagnetized in a normal field. Identification of the original polarity is possible only with some of the specimens, so that accurate positioning of the reversal plane required dense and multiple sampling. Similar precaution at all sites where reversals are used for time-stratigraphic correlations is recommended. Paleomagnetic investigation was particularly useful in proving the presence of unfaulted strata at least 0.5 my old, as required by safety regulations of the U.S. Nuclear Regulatory Commission (NRC). This is due to the fact that any thick layer of reversely magnetized sediment is with high probability older than 0.7 my.     

Palynological evidence for early Holocene aridity in the southern Sierra Nevada, California

Sediments of Balsam Meadow have produced a 11,000-yr pollen record from the southern Sierra Nevada of California. The Balsam Meadow diagram is divided into three zones. (1) The Artemisia zone (11,000–7000 yr B.P.) is characterized by percentages of sagebrush (Artemisia) and other nonarboreal pollen higher than can be found in the modern local vegetation. Vegetation during this interval was probably similar to the modern vegetation on the east slope of the Sierra Nevada and the climate was drier than that of today. (2) Pinus pollen exceeded 80% from 7000 to 3000 yr B.P. in the Pinus zone. The climate was moister than during the Artemisia zone. (3) Fir (Abies, Cupressaceae, and oak (Quercus) percentages increased after 3000 yr B.P. in the Abies zone as the modern vegetation at the site developed and the present cool-moist climatic regime was established. Decreased fire frequency after 1200 yr B.P. is reflected in decreased abundance of macroscopic charcoal and increased concentration of Abies magnifica and Pinus murrayana needles.     

Chemical character of return irrigation water in tropical volcanic islands

Unequivocal identification of irrigation return water through routine chemical analyses does not appear possible in tropical volcanic islands. Several constituents, nevertheless, will suggest an agricultural source if they are present in large concentrations. Nitrate is the most useful indicator; background concentrations are generally less than 2 ppm but return irrigation water will commonly have concentrations of between 5 and 50 ppm. Sulfate appears to be the next most useful indicator. Calcium, silica, and bicarbonate have also been reported to be significant. Where detailed studies have been made of agricultural water balances, regional ground-water flow directions, and deep-well hydraulics, hydrochemistry can provide critical supporting data for the identification of return irrigation water which could be a potential ground-water pollutant.