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Data from the Imaging Riometer for Ionospheric Studies (IRIS) at Kilpisjärvi, Finland, have been compiled to form statistics of auroral absorption based on seven years of observations. In a previous study a linear relationship between the logarithm of the absorption and the Kp index provided a link between the observations of precipitation with the level of geomagnetic activity. A better fit to the absorption data is found in the form of a quadratic in Kp for eight magnetic local time sectors. Past statistical investigations of absorption have hinted at the possibility of using the solar wind velocity as a proxy for the auroral absorption, although the lack of available satellite data made such an investigation difficult. Here we employ data from the solar wind monitors, WIND and ACE, and derive a linear relationship between the solar wind velocity and the cosmic noise absorption at IRIS for the same eight magnetic local time sectors. As far as the authors are aware this is the first time that in situ measurements of the solar wind velocity have been used to create a direct link with absorption on a statistical basis. The results are promising although, it is clear that some other factor is necessary in providing reliable absorption predictions. Due to the substorm related nature of auroral absorption, this is likely formed by the recent time history of the geomagnetic activity, or by some other indicator of the energy stored within the magnetotail. For example, a dependence on the southward IMF (interplanetary magnetic field) is demonstrated with absorption increasing with successive decreases in Bz; a northward IMF appears to have little effect and neither does the eastward component, By. Key words. Magnetospheric physics (energetic particles, precipitating; solar wind-magnetosphere interactions) – Ionosphere (modeling and forecasting)

International audience; A C-25 terpenoid, pseudopulchellol, a rare example of a compound formed by the combination of a monoterpenoid and a sesquiterpenoid unit, was isolated along with eudesm-4(15)-en-1β,6α-diol, its likely precursor, and nine known compounds, including six ent-kaurenoic acids, from the leaves of Croton pseudopulchellus. The Logic for Structure Determination (LSD) protocol was used to determine that pseudopelchellol consisted of the sesquiterpene, eudesm-4(15)-ene-6α-ol, attached at the C-1β position to C10 of the monoterpene, α-pinene. The Electronic circular dichroism (ECD) studies were used to assign the absolute configuration of pseudopulchellol.

Observations at Sanae, Antarctica of a pulsating aurora with a low light level T. V. system have been combined with simultaneous recordings of VLF hiss on a broad band receiver. Both auroral light and hiss intensities display a significant peak at 1.3Hz in the power spectrum. The peaks in the auroral light intensity variations lead those in the VLF hiss by times between zero and 0.2s, as revealed by cross-spectral analysis. These results are explained in terms of cyclotron resonance in the equatorial plane between the auroral electrons and echoing VLF hiss.

Whistler data recorded continuously at Sanae, Antarctica (L=4) over a 24 hour period of quiet magnetic conditions (average Kp=1) have been analysed to obtain plasma convection patterns. A duskside plasmaspheric bulge is present, centered on 1700 UT. The westward electric fields determined for this bulge region suggest that quiet time plasma drift is predominantly controlled by internal ionospheric current systems of dynamo origin, while in a limited local time sector there is some evidence of the magnetospheric dawn-to-dusk electric field being responsible.

Most of the studies on the large igneous provinces (LIPs) focus on Phanerozoic times, and in particular, those related to the disruption of Pangea (e.g. CAMP, Karoo, Parana–Etendeka) while Precambrian LIPs (e.g. Ventersdorpf, Fortescue) remain less studied. Although the investigation of Precambrian LIPs is difficult because they are relatively poorly preserved, assessment of their geochemical characteristics in parallel with younger overlapping LIP is fundamental for monitoring the evolution of the mantle composition through time. Recent 40Ar/39Ar dating of the Okavango giant dyke swarm (and related sills) in southern Africa showed that ~ 90% of the dykes were emplaced at 179 ± 1 Ma and belong to the Karoo large igneous province whereas ~ 10% of dykes yielded Proterozoic ages (~ 1–1.1 Ga). Here, we provide new major, trace and rare earth elements analyses of the low-Ti Proterozoic Okavango dyke swarm (PODS) that suggest, combined with age data, a cognate origin with the 1.1 Ga Umkondo large igneous province (UIP), southern Africa. The geochemical characteristics of the PODS and UIP basalts are comparable to those of overlapping low-Ti Karoo basalts, and suggest that both LIPs were derived from similar enriched mantle sources. A mantle plume origin for these LIPs is not easily reconciled with the geochemical dataset and the coincidence of two compositionally similar mantle plumes acting 900 Myr apart is unlikely. Instead, we propose that the Umkondo and Karoo large igneous provinces monitored the slight evolution of a shallow enriched lithospheric mantle from Proterozoic to Jurassic.

The objective of this research was to evaluate the internal thermal environment of two broiler barns featuring different ventilation systems representative of Brazilian and South American poultry production industry: (a) a negative-pressure tunnel and (b) a positive-pressure lateral ventilation system. Environmental parameters such as dry bulb temperature, relative humidity and temperature-humidity index were assessed; temperature maps for day and night average conditions were determined for the first three weeks of life. Better uniformity of the thermal environment and comfort conditions inside the negative-pressure tunnel were found. RESUMO Objetivou-se, nesta pesquisa, avaliar o ambiente térmico interno de dois galpões de frangos de corte com diferentes sistemas de ventilação representativos da indústria de produção de aves de corte brasileira e sul-americana: (a) um com pressão negativa tipo túnel e (b) outro com ventilação lateral e pressão positiva. Parâmetros ambientais do conforto térmico, tais como temperatura de bulbo seco, umidade relativa e índice de temperatura e umidade, foram avaliados; mapas de temperaturas médias para as condições de dia e noite foram determinadas nas três primeiras semanas de vida das aves. Melhor uniformidade ambiental e condições de conforto térmico no interior do galpão com pressão negativa foram observadas.

International audience; The ~ 183 Ma old Karoo Large Igneous Province extends across southern Africa and is related to magmatism in Antarctica (west Dronning Maud Land and Transantarctic Mountains) and parts of Australasia. Intrusive events, including the emplacement of at least ten dyke swarms, occurred between ~ 183 Ma and ~ 174 Ma. We review here the field evidence, structure and geochronology of the dyke swarms and related magmatism as it relates to melt sources and the mantle plume hypothesis for the Karoo LIP. Specifically, the magma flow-related fabric(s) in 90 dykes from five of these swarms is reviewed, paying particular attention to those that converge on triple junctions in southern Africa and Antarctica. The northern Lebombo and Rooi Rand dyke swarms form an integral part of the Lebombo monocline, which converges upon the Karoo triple junction at Mwenezi, southern Zimbabwe. Dykes of the Northern Lebombo dyke swarm (182-178 Ma) appear to have initially intruded vertically, followed later by lateral flow in the youngest dykes. In dykes of the Okavango dyke swarm (178 Ma) there is evidence of steep magma flow proximal to the triple junction, and lateral flow from the southeast to the northwest in the distal regions. This is consistent with the Karoo triple junction and the shallow mantle being a viable magma source for both these dyke swarms. In the Rooi Rand dyke swarm (174 Ma) there is also evidence of vertical and inclined magma flow from north to south. This flow direction cannot be reconciled with the Karoo triple junction, as the northern termination of the Rooi Rand dyke swarm is in east-central Swaziland. The Jutulrøra and Straumsvola dyke swarms of Dronning Maud Land display evidence of sub-vertical magma flow in the north and lateral flow further south. The regional pattern of magma flow is therefore not compatible with direction expected from the Weddell Sea triple junction. The overall flow pattern in Karoo dykes is consistent with the triple junction being an important magma source. However, the Limpopo Belt and Kaapvaal Craton have significantly controlled the structure and distribution of the Lebombo and Save-Limpopo monoclines and the Okavango dyke swarm. The locus of magma flow in dykes of Dronning Maud Land is at least 500 km from the Karoo triple junction, as is the apparent locus for the Rooi Rand dyke swarm. In comparison with recent modelling of continental assembly, the structure and flow of the dyke swarms, linked with geochronology and geochemistry, suggests that thermal incubation during Gondwana assembly led to Karoo magmatism. A plate tectonic, rather than a fluid dynamic plume explanation, is most reasonably applicable to the development of the Karoo LIP which does not bear evidence of a deep-seated, plume source.

Zhongshan Station in Antarctica is located close to the polar cusp/cleft latitude. The field of view of the Syowa East HF radar also covers Zhongshan Station. Simultaneous quasi-periodic phenomena of optical aurora, HF radar backscatter power and Doppler velocity, and ground based magnetograms were observed in the magnetic postnoon sector (～330 MLT to 1510 MLT) on 3 August 1997. The characteristics of the quasi-periodic event are summarized in the following; 1) East-west aligned band/arc type discrete aurora showed quasi-periodic luminosity variations with period of -6-10 min, 2) Quasi-periodic variations of the optical aurora had one to one correspondence with the variations of HF radar backscatter powers and magnetic pulsations, 3) The HF backscatter region was located at the lower latitude of the quasi-periodic optical aurora, 4) Quasi-periodic variations of line-of-site Doppler velocity detected by HF radar showed very close relation to the magnetic pulsations observed at Zhongshan in Antarctica and the IMAGE magnetometer array in the northern hemisphere, 5) The IMAGE data revealed that the region of quasi-periodic HF radar backscatter (irregularities) corresponds to the region of intensity maximum of magnetic pulsations.

Moisture content (Psi) of poultry manure or litter is an important property of the material. Relating manure or litter Psi to its ammonia (NH3) emission is conducive to assessing and/or controlling real-time ammonia emissions from the manure or litter. However; means to measure manure or litter on a real-time basis is lacking. This study was carried out to characterize the operational performance of a commercially available soil moisture sensor for measuring V of meat-bird (broiler and turkey) litters and laying-hen manure. The Psi tested ranged from 27.1% to 65.7% for broiler litter, 22.8% to 56.1% for turkey litter, and 11.0% to 75.0% for layer manure. Bulk density (rho) ranged from 318 to 468 kg m(-3) (20 to 29 lb ft(-3)) for the broiler and turkey litters and from 151 to 943 kg m(-3)(9 to 55 lb ft(-3)) for laying-hen manure. Linear regression equations were developed to relate the sensor output to Psi and rho for the meat-bird litters and to Psi for the laying-hen manure, all yielding good fit (R-2=0.95 -0.99). An uncertainty analysis performed on the developed calibration equations revealed average errors in the V estimation of +/- 7.1% estimated value for the poultry litters and +/- 6.7% estimated value for the laying-hen manure. Litter temperature was found to have a small impact on Psi measurement by the sensor, 0.31% of measured mV per degrees C (0.17% per degrees F) deviation from the mean operating temperature over the range of 4 degrees C to 24 degrees C (39 degrees F to 75 degrees F). Results of the study indicate that when properly calibrated, the soil moisture sensor offers a reasonable means for real-time measurement of poultry litter or manure moisture content.

International audience; Magmatic (type-A) fabric co-exists with dyke-orthogonal (type-B) fabric in both the plagioclase and opaque grain fractions in dykes of the Rooi Rand dyke swarm (RRDS). We present new data from the RRDS pertaining to the size, shape, texture and orientation of plagioclase. Texturally, the samples range from intersertal to sub-ophitic and phenocrystic (plagioclase-phyric). More than 90% of plagioclase grains are

International audience; The orientation of magnetic and petrofabric in 14 mafic dykes of the Northern Lebombo dyke swarm (NLDS) has been determined using the anisotropy of magnetic susceptibility (AMS) and mineral shape preferred orientation (SPO) in order to constrain the magma flow direction during dyke emplacement. The N-S striking NLDS intruded the N-S trending; 700. km long Lebombo faulted monocline between 182 and 178. Ma. The Lebombo faulted monocline, which forms the eastern-most sub-province of the Karoo large igneous province (LIP), is essentially a volcanic rifted margin with a protracted magmatic and tectonic history related to the break-up of southern Gondwana. It also forms the southern limb of the Karoo triple-rift system which has been hypothesised to have formed by a mantle plume centred on the triple junction locus. The other two arms of the rift which converge on the triple junction are the WNW trending Okavango dyke swarm (ODS) and NE trending Save-Limpopo dyke swarm (SLDS). In the NLDS it is found that the magnetic fabric, which is of magmatic origin in ~. 50% of the samples, is carried predominantly by stoichiometric magnetite. There is remarkable agreement between the orientations of the AMS and SPO fabrics and at least two dykes show coaxial AMS and mineral SPO fabric consistent with lateral magma flow from the north. This direction is supported by the imbrication of the foliations of the well-defined bulk AMS and plagioclase SPO fabric when viewed in a dyke co-ordinate system. Although steeply plunging maximum axes occur in the SPO fabric, their possible use as magma flow vectors is questioned because they do not necessarily mimic the elongation of plagioclase grains visible in orientated thin sections. The magnetic and petrofabric of the NLDS is interpreted to have developed during lateral magma flow from the locus of the Karoo triple junction.

International audience; Magma flow direction is recorded in the macroscopic mineral petrofabric and magnetic fabric of the MORB-like Rooi Rand dyke swarm. The bulk magnetic fabric is sub-parallel to the dyke plane, resulting from preferred orientation of grains during magma flow. This is referred to as type-A fabric. A study of mineral shape preferred orientation reveals an additional fabric, which is orthogonal to the average dyke orientation in 30% of the data. This fabric is carried by both plagioclase and opaque grains and would typically be interpreted as 'inverse'. It is referred to here as type-B fabric. However, because it is carried by the shape preferred orientation of macroscopic grains and is in most cases not coaxial to the anisotropy of magnetic susceptibility fabric, it is interpreted as having been acquired during increased grain interaction during late-stage magma flow associated with decreasing magma pressure.

International audience

International audience; Trace elements were analysed in rocks and minerals from three sections across the Merensky Reef in the Rustenburg Platinum Mine in the Bushveld Complex of South Africa. Whole rocks and separated minerals were analysed by inductively coupled plasmamass-spectrometer (ICP-MS) and in situ analyses were carried out by ion microprobe and by laser-source ICPMS. Merensky Reef pyroxenites contain extremely high concentrations of a wide range of trace elements. These include elements incompatible with normal silicate minerals as well as siderophile and chalcophile elements. For major elements and compatible trace elements, the measured concentrations in cumulus phases and the bulk rock compositions are similar. For highly incompatible elements, however, concentrations in bulk rocks are far higher than those measured in the cumulus phases. In situ analyses of plagioclase have far lower concentrations of Th, Zr and rare earth elements than ICP-MS analyses of bulk separates of plagioclase, a difference that is attributed to the presence of traceelement-rich accessory phases in the bulk mineral separates. We used these data to calculate the trace-element composition of the magmas parental to the Merensky Unit and adjacent norites. We argue that there is no reason to assume that the amount of trapped liquid in the Merensky orthopyroxenite was far greater than in the norites and we found that the pyroxenite formed from a liquid with higher concentrations of incompatible trace elements than the liquid that formed the norites. We propose that the Bushveld Complex was fed by magma from a deeper magma chamber that had been progressively assimilating its crustal wall rocks. The magma that gave rise to the Merensky Unit was the more contaminated and unusually rich in incompatible trace elements, and when it entered the main Bushveld chamber it precipitated the unusual phases that characterize the Merensky Reef. The hybrid magma segregated sulphides or platinum-group-element-rich phases during the course of the contamination in the lower chamber. These phases accumulated following irruption into the main Bushveld chamber to form the Merensky ore deposits.

The hypothesis that dark matter and dark energy are unified through the Chaplygin gas is reexamined. Using a generalization of the spherical model which incorporates effects of the acoustic horizon we show that an initially perturbative Chaplygin gas evolves into a mixed system containing cold dark matter in the form of gravitational condensate. Furthermore, we demonstrate that the observed CMB angular and baryonic power spectra are reproduced., Comment: 4 pages, 4 figures, talk by N. Bilic at the 15th Rencontres de Blois, June 2003

Each ozone profile is a unique response to the photochemical and dynamic processes operating in the troposphere and hence is critical to our understanding of processes and their relative contributions to the tropospheric ozone budget. Traditionally, mean profiles, together with some measure of variability, averaged by season or year at a particular location have been presented as a climatology. However, the mean profile is difficult to interpret because of the counteracting influences present in the micro-structure. On the other hand, case study analysis, whilst revealing, only applies to isolated conditions. In a search for pattern and order within ozone profiles, a classification based on a cluster analysis technique has been applied in this study. Ozone profiles are grouped according to the magnitude and altitude of ozone concentration. This technique has been tested with 56 ozone profiles at Johannesburg, South Africa, recorded by aircraft as part of the MOZAIC (Measurement of Ozone and Water Vapor aboard Airbus In-service Aircraft) program. Six distinct groups of ozone profiles have been identified and their characteristics described. The widely recognized spring maximum in tropospheric ozone is identified through the classification, but a new summertime mid-tropospheric enhancement due to the penetration of tropical air masses from continental regions in central Africa has been identified. Back trajectory modeling is used to provide evidence of the different origins of ozone enhancements in each of the classes. Continental areas over central Africa are shown to be responsible for the low to mid-tropospheric enhancement in spring and the mid-tropospheric peak in summer, whereas the winter low-tropospheric enhancement is attributed to local sources. The dominance of westerly winds through the troposphere associated with the passage of a mid-latitude cyclone gives rise to reduced ozone values.

Samples of colostrum, early and late lactation milk from thirteen South African indigenous Nguni goats (SAING) were analysed for contents of total solids (TS), solids-not-fat (SNF), fat, protein, lactose, ash and energy. Relationships between colostrum or milk and some parameters such as litter size (LS), milk yield (MY) and does kidding weight (DKW) were determined. Fat, protein and lactose contents of colostrum were poorly correlated (P > 0.05) with LS. Of relationships between early lactation parameters considered, only the coefficient between MY and DKW was significant (r = 0.72, P < 0.001). Correlations between protein and lactose contents of late lactation milk and LS were not significant (P > 0.05). However, the milk fat content of late lactation milk was significantly correlated with LS (r = 0.23, P = 0.041). Means of TS, SNF, fat and energy contents decreased with increased lactation period while ash content increased as lactation advanced. Protein and lactose contents were at maximum in colostrum and early lactation milk, respectively. Fat and TS contents of colostrum, early and late lactation milk samples were positively and significantly (P < 0.05) correlated. Fat content of colostrum and milk of SAING can be used to predict the dry matter (total solids) constituent of the goats' colostrum and milk. Keywords: Nguni goats; colostrum; milk; composition; natural pastureAfrican Journal of Range & Forage Science 2003, 20(1): 47–51

The structure and evolution of an intense tropical cut-off low (COL) occurring over South Africa is documented, by combining meteorological and ozone data from a number of different sources, such as in situ radiosoundings, Measurement of ozone and water vapor by airbus in-service aircraft data, satellite (Meteosat) and modelled European Center for Medium-Range Weather Forecast data. The COL extends to latitude 10°S, with a lifetime of approximately 2 weeks, and a horizontal size of about 10°. A distinguishing feature of this case study is that it becomes detached from the stratospheric reservoir in both the vertical and horizontal planes, in an irreversible way and as such is different in structure to a mid-latitude or a polar COL. Consequently, even though tropical COLs may occur infrequently, it is likely that the tropospheric ozone enhancement induced by this irreversible intrusion could be significant.

International audience; Approximately three quarters of population in South Africa live in rural areas and they are under the governance of traditional leadership, whose practice has been the source for controversy recently. The institution of traditional leadership has been regarded as the main ruling system closest and accepted by the people at the grassroots level. Local government in South Africa is presently in a process of fundamental transformation. One of the major problems South Africa inherited from apartheid was a structure of race based municipal boundaries. Demarcation is one of the controversial factors dogging the period of local government history. Demarcation was necessary to remove all traces of apartheid borders and to allow for more democratic municipal government.

Volume entitled: Bodies and Politics. Healing Rituals in the Democratic South Africa, Co-ordinated by Véronique FAURE, co-edited by Arnold SHEPPERSON; The story of AIDS in South Africa is a story about what happens when a disease leaps the confines of medicine and invades the body politic of an entire society. Appearing at the dawn of democracy with its promise of a new South Africa where everything would be possible, HIV/AIDS presented itself as a complex plaque with confounding social, economic and political meanings that locked together to accelerate the virus' progress. The country's social dynamics and cultural belief systems colluded and continue to collude to spread the disease and help block effective intervention.

Volume entitled: Bodies and Politics. Healing Rituals in the Democratic South Africa, Co-ordinated by Véronique FAURE, co-edited by Arnold SHEPPERSON; This paper aims to address the conditions which affected and were affected by indigenous medical practice (between the mid-1980s and the mid-1990s) and the consequent opposing responses to such developments. It is argued that the socio-economic and political conditions prevailing between the mid-1980s and the mid-1990s drastically changed the economic, political, social and personal security of Africans, during the time when the responsible state institutions were unable or reluctant to respond to their needs. People who were threatened or under assault therefore found refuge in the protective powers of indigenous medicines. Since some of the conditions they attempted to address were new, indigenous medicines and the practice itself were changed (as they had consistently changed over time) in order to respond effectively to such conditions.