The first case study of a thunderstorm in South Africa based on dual- Doppler radar observations

On 27 March 1991, an isolated thunderstorm passed between the two CSIR Doppler radars, spaced about 45km apart. Both radars simultaneously recorded Doppler data of the storm, and a detailed case study during an 11-min period is presented. Air motions synthesized from these data provide the first three-dimensional display of Doppler-derived wind fields within a multicell storm on the Transvaal Highveld. Regions of high divergence values (10 -2s -1) at low levels were found mostly in close proximity to reflectivity maxima (45-51 dBZ), which is consistent with findings from North America, that gravitational loading by the precipitation plays a key role in the initiation and maintenance of downdraughts. -from Authors

Programa de controle de surto de escorpião Tityus serrulatus, Lutz e Mello 1922, no município de Aparecida, SP (Scorpiones, Buthidae).

A scorpion control program was proposed for the town of Aparecida (SP), an endemic region of Tityus serrulatus. Clusters of scorpions in urban and rural areas, environmental degradation of the town's outskirts and new scorpion procreation and dispersal habitats were studied. In addition, infrastructure problems such as the disposal and collection of residential and municipal refuse, sanitation (sewage and storm sewer), condition of vacant lots and constructions in the urban area were evaluated. After an epidemiological study, educational measures such as the distribution of pamphlets, cleaning group work, visits to residences and cooperation from High School teachers and students were also suggested. Chemical control was indicated in high-risk sites, especially those of near-school buildings. Furthermore, the use of natural predators was also mentioned within the present sanitation regulations for urban areas. The authors assert that these procedures must be integrated and continued uninterruptedly for several years. They also suggest a collaborative work with those responsible for the dengue eradication program, as well as the institution of the scorpion study week, which would greatly contribute to the education of the population, to preventive programs and to scorpion control.

Statistics on tropical convective storms observed by radar

Convective storm rainfall is of special importance to urban hydrological studies due to its temporal and spatial variability. Although dense networks of recording rain gauges can be employed to characterize such rainfall, very few investigations of this type have been undertaken due to their prohibitive cost. This paper reports some data on characteristics of tropical convective storms obtained from radar at Bauru in the State of São Paulo, Brazil. Periods of convective precipitation were identified by exclusion of those related to frontal activity with the help of synoptic maps and the radar screen record. The occurrence and evolution of convective storms were observed in two 28 km × 28 km windows obtaining information on the life history of convective cells and the magnitude of rainfall. Frequency distributions of the time of occurrence of convective rainfall, cell size, area covered, life duration and maximum and average rainfall observed in the experimental areas are presented and discussed.

Gênese e Classificação da Coquina de Camaquã, Formação Corumbataí (Neopermiano), na Região de Rio Claro, SP

Analysis of the taphonomic signatures of a well preserved, silicifled coquina (Pinzonella neotropica assemblage) from the Camaquã outcrop, upper part of the Corumbataí Formation (Late Permian), in the Rio Claro region, state of Sáo Paulo, allowed interpretation of processes involved in its origin as related to high energy events (storms). The coquina occurs as a lenticular body, 2-11 cm thick and extending laterally for about 120 m. Basal contact of the coquina is sharp and erosive. Its upper contact is sharp. The concentration is dominated by pelecypods including the shallow burrowers (Pinzonella neotropica, Jacquesia brasiliensis), intermediate burrower (Pyramus anceps) and semi-infaunal forms (Naiadopsis lamellosus). All these species are suspension feeders. Besides sand-sized or even smaller shell fragments, there occur disarticulated, complete shells which are commonly abraded but do not show any signs of bioerosion or incrustation. In vertical side view, the shells are mainly convex-up, nested or stacked, while in plan-view they show random orientation. Multiple discontinuous grading is visible. These taphonomic signatures suggest that the origin of the skeletal accumulation is related to high energy events (possibly storm flows) in a proximal environment. The amalgamated nature of the Camaquã coquina records several episodes of erosion and deposition.

Aspectos da biologia reprodutiva de Syrigma sibilatrix (Ardeidae, Aves)

A nest (12.7 m height) of Syrigma sibilatrix was studied on the campus of UNESP Rio Claro (São Paulo, Brazil). The nest was in a fork in the tree Machaerium nyctitans (Leguminosae). Focal observations (n = 103 h) were carried out from 13 September 2004 to 1 November 2004. The male and female both participated in nest building, which took 37 days, mainly between 05:00h - 11:00h. Sticks for the nest were collected at the rate of 5.7 ± 3.4 sticks hour -1, most by the male. The nest included 197 sticks, and was a fl at platform with diameter = 75cm, and depth = 14 cm. A single egg was laid and was incubated (by both sexes) for 66h57 (92% of the time of permanence of the individuals in the nest). The egg was moved 97 times (1.34 times/hour). A strong storm caused the egg to fall, interrupting the study.

Conseqüências de uma tempestade geomagnética no posicionamento relativo com receptores GPS de simples freqüência

The error associated with the ionosphere depends on Total Electron Content (TEC) of the ionosphere. The geomagnetic field exerts strong influence in the TEC variation, because it controls the movement of the electrons. After solar events the magnetic lines of force can be compressed, characterizing the geomagnetic storm. The aim of this paper is to present to geodesic community the effects of a geomagnetic storm in the relative positioning. The processing of the data was accomplished with an interval of two hours, with a 430 km baseline. The analyze of the obtained results have been carried out from the discrepancies between the true coordinates and corresponding ones obtained in the processing of the baseline. The used data in this paper include the period of 30/03/2001 up to 02/04/2001. In March 31 a strong geomagnetic storm happened. One day after, that it corresponds to main phase of the storm, the values of the discrepancies decreased significantly. For instance, in 01:00-03:00 UT period, the value of the planimetric discrepancy reached 20 m in the storm day. However, in the main phase of the storm, the planimetric discrepancy decreased to 0.1 m.

Towards forecasting and mitigating ionospheric scintillation effects on GNSS

The effect of the ionosphere on the signals of Global Navigation Satellite Systems (GNSS), such as the Global Positionig System (GPS) and the proposed European Galileo, is dependent on the ionospheric electron density, given by its Total Electron Content (TEC). Ionospheric time-varying density irregularities may cause scintillations, which are fluctuations in phase and amplitude of the signals. Scintillations occur more often at equatorial and high latitudes. They can degrade navigation and positioning accuracy and may cause loss of signal tracking, disrupting safety-critical applications, such as marine navigation and civil aviation. This paper addresses the results of initial research carried out on two fronts that are relevant to GNSS users if they are to counter ionospheric scintillations, i.e. forecasting and mitigating their effects. On the forecasting front, the dynamics of scintillation occurrence were analysed during the severe ionospheric storm that took place on the evening of 30 October 2003, using data from a network of GPS Ionospheric Scintillation and TEC Monitor (GISTM) receivers set up in Northern Europe. Previous results [1] indicated that GPS scintillations in that region can originate from ionospheric plasma structures from the American sector. In this paper we describe experiments that enabled confirmation of those findings. On the mitigation front we used the variance of the output error of the GPS receiver DLL (Delay Locked Loop) to modify the least squares stochastic model applied by an ordinary receiver to compute position. This error was modelled according to [2], as a function of the S4 amplitude scintillation index measured by the GISTM receivers. An improvement of up to 21% in relative positioning accuracy was achieved with this technnique.

Circulação recente de sedimentos costeiros nas praias de santos durante eventos de tempestades: Dados para a gestão de impactos físicos costeiros

The beachs of Santos are situated in Santos Bay, central portion of paulista coast, in São Paulo state. This beachs are frequently affected by cold fronts with winds and currents from the South. These fronts are responsible for the removal and transport of sediments (sand) in Santos beaches. In order to quantify this sedimentation the channels of Santos were analysed, due to their function as box colectors of sediments during storm events. The channels are filled by sands, which volume in channels 1 to 6 was estimated, by using the length, width and height of sand sedimented in the channels, in the event of 22-27 april 2005. The chanels 2, 3 and 1 presented the larger volumes of sands, confirming that the central and SW portion of the beaches of Santos present higher levels of sedimentation or re-sedimentation. That is due to the transport by ocean waves and currents and currents from the Channel of the Port of Santos. This central portion suffer invasion of marine water over street and buildings, caracterizated of geological rise area.

Metacryphaeus rotundatus, um novo elemento da fauna de trilobites calmoniidae (phacopida), da formação Ponta Grossa (Devoniano), bacia do Paraná, Brasil

Calmoniids (Delo, 1935) are the most common and abundant group of trilobites of the fossil record of the Devonian Ponta Grossa Formation in the Apucarana sub-basin. Although known since the past century, the study of calmoniids has been taxonomically and stratigraphically biased. This is because some authors centered their studies on some particular genera from a few stratigraphic horizons within the basal portion of the Ponta Grossa Formation. The analyses of 398 specimens of calmoniid trilobites of the rocks of Jaguariaiva Member of the Ponta Grossa Formation, mainly from Tibagi county in the state of Paraná, Brazil, indicate the presence of specimens that are referable to Metacryphaeus rotundatus (Kozlowski, 1923). This is the first record of M. rotundatus in Brazilian Devonian rocks. Metacryphaeus rotundatus is a conspicuous species of the Emsian rocks of the Icla Formation, Bolivia. Although the affinities of the trilobite fauna of the Devonian Paraná Basin, in the context of the Malvinokaffric realm, are with the Brazilian and South Africa provinces, this finding is in accordance with new evidence (e.g., conulariids, homalonotids trilobites), indicating the presence of cosmopolitan species with Andean affinities. Metacryphaeus rotundatus lived in a broad paleoclimatic range, from a temperate, cold temperate to a subpolar climate. Finally, in the Devonian of the Paraná Basin, M. rotundatus lived and were preserved in muddy, organic rich bottoms, deposited in offshore waters, below the storm wave base, associated to marine flooding surfaces.

Chronostratigraphy and radiocarbon age inversion in the Holocene regressive barrier of Paraná, southern Brazil

Twenty-two 14C datings were performed at the central sector of the Paraná coast to define Holocene regressive barrier evolution. The barrier Pleistocene substratum was ascribed an age between 40 400 and 30 000 yr BP, but it can also represent the penultimate sea level highstand during marine isotope stage 5e. The Holocene barrier samples provided ages between 8542-8279 and 2987-2751 cal yr BP, and showed at least six age inversions that were related to age differences between in situ or low-distance transported shells or trunk fragments, and high-distance transported vegetal debris, wood fragments and organic matter samples. The regressive Holocene barrier age was 4402-4135 cal yr BP near the base, and 2987-2751 cal yr BP near the top. Most of the vegetal remains were transported by ebb tidal currents from the estuaries to the inner shelf below wave base level during the mid-Holocene highstand; they were transported onshore by storm waves and littoral currents during the sea level lowering after the sea level maximum, and were deposited mainly as middle shoreface swaley cross-stratification facies. © 2008.

El Salvador: impacto socioeconómico, ambiental y de riesgo por la baja presión asociada a la tormenta tropical Ida en noviembre de 2009

Incluye Bibliografía

Capital flows to emerging economies: does the emperor have clothes?

Includes bibliography

Financial crisis and national policy issues: an overview

Includes bibliography

Liquidity black holes: why modern financial regulation in developed countries is making short-term capital flows to developing countries even more volatile

Includes bibliography