Initial Sedimentation Research Articles

Poster 141: Case Report: Debilitating Sweet’s Syndrome in an Acute Rehabilitation Setting

Setting: Tertiary care medical center. Patient: A 73-year-old man with Sweet’s syndrome. Case Description: This patient presented with a history of Sweet’s syndrome, ulcerative colitis, and polymyalgia rheumatica. He was admitted to the hospital with increasing bloody diarrhea, abdominal pain, and severe diffuse joint and muscle pains, negatively affecting his gait and activities of daily living. His initial erythrocyte sedimentation rate and C-reactive protein were both 140. Assessment/Results: His acute flare was treated successfully with intravenous infliximab (Remicade), steroids, and cyclosporine, with resolution of his abdominal pain and diarrhea.

Effect of inclination on gas-fluidized beds of fine cohesive powders

Results are presented of an experimental investigation on how bed inclination affects the fluidization and sedimentation behavior of fine cohesive particles. In contrast with the expected Geldart C behavior, and due to self-agglomeration, these fine particles are uniformly fluidized by gas in a vertically oriented bed, displaying a fluid-like regime and expanding smoothly as the gas velocity is increased. When the gas flow supply to the bed is suddenly stopped, the initial sedimentation velocity of the vertically oriented bed is similar to the fluidizing gas velocity as corresponds to uniform fluidization. The main effect of inclination is to induce fluidization heterogeneity. The local gas velocity increases in the adjacent region to the upper wall at the expense of the region adjacent to the lower wall. This situation anticipates the onset of local bubbling in the region adjacent to the upper wall. Meanwhile the region adjacent to the lower wall remains in a solid-like state and does not reach the fluid-like state until values of the gas flow are applied much higher than those needed in a vertical fluidized bed. As a consequence, the expansion and fluidization uniformity of the tilted bed are hindered. If the gas supply to the inclined bed is suddenly stopped, and because of induced heterogeneity, sedimentation takes place at a decreased rate as compared with sedimentation velocity in the uniformly fluidized vertical bed.

Alpine ocean seafloor spreading and onset of pelagic sedimentation: new radiolarian data from the Chenaillet-Montgenèvre ophiolite (French-Italian Alps)

Radiolarians of Middle Jurassic age (tentatively middle Bathonian) provide the first direct age determination from oceanic sediments associated with the Chenaillet-Montgenèvre ophiolite (Piemonte zone, French-Italian Alps). This datum obtained from radiolarites of the Lago Nero- Replatte thrust sheet is older than those previously established on ophiolite sedimentary covers from this segment of the western Alps. It also shows that Lago Nero-Replatte basal radiolarites are anterior to the youngest intrusives from the overlying Chenaillet s.s. thrust sheet. This chronological relationship implies either a late seafloor spreading-related magmatic activity in places younger than adjacent initial pelagic sedimentation, or more likely that the Lago Nero-Replatte and the Chenaillet s.s. thrust sheets are distinct and distant pieces of lithosphere that were eventually stacked together: the Lago Nero-Replatte unit was trapped within the accretionary wedge while the Chenaillet s.s., of a younger age and in a more distal position with regards to the European margin, was obducted. Regionally, the Lago Nero-Replatte sediments appear to be coeval to other Bathonian supraophiolitic radiolarites exposed in the western Alps. These results strengthen the Bathonian correlation of widespread seafloor spreading in both western Tethys and the central Atlantic ocean.

The Jangsan and Myeonsan formations (Early Cambrian) of the Taebaek Group, mideast Korea: depositional processes and environments

The present study focuses on the depositional processes and environments of the lower part of the Taebaek Group (Cambrian-Ordovician) during the initial basin-forming inundation of the Taebaeksan Basin, an eastern margin of the North China platform. The lowermost part of the Taebaek Group is represented by two contrasting lithologic units, the Jangsan and Myeonsan formations. The Jangsan Formation consists of cross-bedded, massive, and foreset-bedded quartzose sandstone (quartzite) interpreted as shallow marine deposits ranging from inner shelf to nearshore environments. Deposition occurred in a stable cratonic basin where continuous subsidence and the accompanied sea-level rise accommodated large supply of sediments. The Myeonsan Formation comprises basal disorganized conglomerate, cross-bedded and laminated sandstone, and homogeneous or laminated mudstone, which largely formed in a tidally influenced restricted embayment. The formation is localized in the margin of the basin, as represented by the basal mass-flow conglomerate and the rapid transition to the tide-influenced marine succession. In the Early Cambrian, initial sedimentation in the Taebaeksan Basin was largely controlled by abundant sediment supply, accompanied with sea-level rise.

Biological wastewater treatments for metallurgical industries

Variable contents of nitrite (NO2 −)- and nitrate (NO3 −)-nitrogen are present in wastewater of metallurgical cylinder-producing industries after treatment in a physical-chemical plant. Biological denitrification and oxidation treatments to reduce the oxidized nitrogen forms to within legal limits were evaluated. Wastewater streams were characterized and quantified in order to build a pilot plant, improve strategies to reduce environmental impact and increase water recycling. Initial sedimentation of raw mixed streams reduced iron and zinc contents by 87% and 71%, respectively. The resulting COD was refractory to be used in biological phases and an added carbon source was necessary to optimise the denitrification process. The biological treatment gave good results even without subsequent physical-chemical treatments, lowering NO2 − and NO3 − values to below the 0.6 and 20 mg L−1 limits respectively.

On features of ferrofluid convection caused by barometrical sedimentation

The experimental and numerical studies of Rayleigh convection in a thin cylindrical layer have been conducted for a ferrofluid containing magnetite particles suspended in kerosene carrier liquid. Near the onset of convection, the wave oscillatory convection was observed both in the experiments and in the numerical finite volume simulations. Time periods of temperature oscillations obtained using thermocouples were investigated using wavelet analysis. Thermosensitive liquid crystal sheet visualizations of flow patterns revealed irregular spatiotemporal behavior of convection, close to the threshold. Numerical simulations using a two-phase mixture model indicated that the initial sedimentation gradient may lead to spatiotemporally chaotic convection. Experimentally observed hysteresis and strong dependence of the measured heat flux from the prehistory of the experiments allude to non-Newtonian nature of ferrocolloids.

Tertiary tectonics of the sub-Andean region of the North Patagonian Andes, southern central Andes of Argentina (41–42°30′S)

The sub-Andean region of the North Patagonian Andes is located between the north Patagonian foreland and the highest elevations of the Andean Cordillera. Its Tertiary contractional structure, active since the upper Late Oligocene and through the upper Late Miocene, corresponds to the external sector of the North Patagonian Andes fold-and-thrust belt, which is characterized by east-vergent thrusts that affect stratified Cenozoic rocks. The units involved in the deformation correspond to El Maitén Oligocene volcanic belt, deformed between east-vergent thrusts and backthrusts, and Oligocene–Miocene sedimentary rocks of the Ñirihuau–Collón Curá Basin. The northern sector of the basin was structured as a thin-skinned fold belt that comprises the Ñirihuau fold belt and a frontal sedimentary wedge. To the south, sedimentary depocenters are confined between medium- to high-angle reverse faults with evidence of basement structural control. In both cases, the general tectonosedimentary framework shows the youngest units toward the east, in agreement with the advance of the orogenic wedge. Most of the Ñirihuau–Collón Curá Basin infill fits a foreland basin system model. Some sectors of the basin show evidence of structural control by normal faults in the initial sedimentation stages. This early extensional regime might be associated with late phases of Oligocene volcanism. Extensional structures probably were partially reactivated during the upper Late Oligocene, as suggested by seismic data.

Reconstructing high-magnitude/low-frequency landslide events based on soil redistribution modelling and a Late-Holocene sediment record from New Zealand

A sediment record is used, in combination with shallow landslide soil redistribution and sediment-yield modelling, to reconstruct the incidence of high-magnitude/low-frequency landslide events in the upper part of a catchment and the history of a wetland in the lower part. Eleven sediment cores were obtained from a dune-impounded wetland at Te Henga, west Auckland, northern New Zealand. Sediment stratigraphy and chronology were interpreted by radiocarbon dating, foraminiferal analysis, and provisional tephrochronology. Gradual impoundment of the wetland began c. 6000 cal yr BP, coinciding with the start of a gentle sea-level fall, but complete damming and initial sedimentation did not begin until c. 1000 cal yr BP. After damming, four well-defined sediment pulses occurred and these are preserved in the form of distinct clay layers in most of the sediment cores. For interpreting the sediment pulses, a physically based landslide model was used to determine spatially distributed relative landslide hazard, applicable at the catchment scale. An empirical landslide-soil redistribution component was added and proved able to determine the volumes and spatial pattern of eroded and deposited soil material, sediment delivery ratio and the impact on total catchment sediment yield. Sediment volumes were calculated from the wetland cores and corresponding landslide scenarios are defined through back-analysis of modelled sediment yield output. In general, at least four major high-magnitude landslide events, both natural and intensified by forest clearance activities, occurred in the catchment upstream of Te Henga Wetland during the last c. 1000 years. The spatial distribution of modelled critical rainfall values for the catchment can be interpreted as an expression of shallow landslide hazard. The magnitude of the sediment pulses represented in the wetland can be back-calculated to critical rainfall thresholds representing a shallow landslide model scenario.

Holocene glaciation and climate evolution of Baffin Island, Arctic Canada

Lake sediment cores and cosmogenic exposure (CE) dates constrain the pattern of deglaciation and evolution of climate across Baffin Island since the last glacial maximum (LGM). CE dating of erratics demonstrates that the northeastern coastal lowlands became ice-free ca.14 ka as the Laurentide Ice Sheet (LIS) receded from its LGM margin on the continental shelf. Coastal lakes in southeastern Baffin Island started to accumulate sediment at this time, whereas initial lacustrine sedimentation was delayed by two millennia in the north. Reduced organic matter in lake sediment deposited during the Younger Dryas chron, and the lack of a glacial readvance at that time suggest cold summers and reduced snowfall. Ice retreated rapidly after 11 ka but was interrupted by a widespread readvance of both the LIS and local mountain glaciers ∼9.6 ka (Cockburn Substage). A second readvance occurred just before 8 ka during a period of unusually cold summers, corresponding to the 8.2 ka cold event in the Greenland Ice Sheet. Most local glaciers were behind their present margins before 7 ka, and in some instances much earlier, although the Foxe Dome of the LIS continued to slowly retract toward the present day Barnes Ice Cap throughout the Holocene. Pollen in lake sediments is rare and dominated by exotic sources prior to 12 ka. Subsequently, grass tundra became established, followed by modern tundra vegetation ca. 8 ka, with subtle changes in pollen assemblages in the late Holocene. Lake primary productivity peaked in the early Holocene, before terrestrial vegetation or marine surface waters reached their apparent thermal maxima. Lacustrine, marine, and glacial proxies all reflect significant late Holocene cooling. The onset of Neoglaciation is well dated in lacustrine records at ca. 6 ka, with intensification after 2.5 ka. The expansion of local glaciers during the Little Ice Age represents the most extensive advance since 7 ka. We suggest that the replacement of Atlantic surface waters by cold, low-salinity Arctic Ocean water, coupled with the steady reduction of summer insolation, resulted in a significant positive sea-ice feedback that produced a larger late Holocene summer temperature depression over the Baffin region than in the Pacific sector of the Arctic.

Arc to rift transitional volcanism in the Santa Rosalía Region, Baja California Sur, Mexico

Middle to late Miocene volcanic rocks in the Santa Rosalía basin region, Baja California Sur, record the transition from arc- to rift-related volcanism associated with the initial opening of the Gulf of California. New K–Ar age dates have led to the identification of three distinct sequences: (1) 24 to 13 Ma arc lavas of the Andesite of Sierra Santa Lucia (ASL) suite; (2) 13 to 10 Ma Santa Rosalía dacite (SRD), representing the final products of subduction-related volcanism; and (3) a diverse rift-related volcanic assemblage that erupted between 11 and 7.7 Ma, which consists of: (1) 11 to 9 Ma Boléo basalts (BTB) to basalt andesites (BBA); (2) the El Morro tuff (EMT), a 10.5- to 7.9-Ma lapilli tuff to ignimbritic unit; and (3) 11 to 10 Ma clinopyroxene-dominant and 9 to 7.7 Ma hornblende-dominant high-K andesites of the Cerro San Lucas (CSL) suite. The BTB-BBA suite is equivalent to regional early rift tholeiitic basalts, while the CSL suite is representative of the regional high-Mg andesite (bajaite) lavas. K–Ar geochronology of EMT tuff has constrained the timing of initial basin sedimentation to after 8 Ma. All lava suites are calc–alkaline with arc-like signatures and are characterized by LILE and LREE enrichment and N-MORB-like patterns of HFSE and HREE. Such signatures are consistent with melts being derived from a mantle that was metasomatized by slab-derived aqueous fluids and silicic melts. Nb–Ta–Ti depletions that characterize the ASL and CSL suites are evidence of aqueous fluid metasomatism, since fluids were depleted in these elements due to residual rutile in the dehydrating slab. Evidence supporting the partial melting of an adakite-altered mantle comes from the relative depletion in HREE of CSL lavas and adakite-like characteristics of both SRD and CSL lavas. ASL lavas are generated from the partial melting of the sub-arc wedge after extensive slab-derived aqueous fluid metasomatism, followed by extensive calc–alkaline crystal fractionation (±amphibole accumulation) and variable degrees of crustal assimilation. SRD are interpreted to be slab melts that hybridized a significant mantle component. BTB, BBA and CSL rift lavas are the products of moderate degrees of partial melting of an adakite and aqueous fluid metasomatized mantle, with the principal control on melt chemistry being the extent of adakite contamination and degree of partial melting. Clinopyroxene-bearing CSL lavas appear to have undergone varying degrees of mixing with co-eruptive SRD melts.

Predictors of Recurrent Ischemic Optic Neuropathy in Giant Cell Arteritis

The competing interests of preventing recurrent ischemic optic neuropathy (ION) and minimizing medication side effects make corticosteroid dose reduction in giant cell arteritis (GCA) a difficult problem. The authors sought to determine whether any factors were predictive of recurrent ION. Retrospective review of the records of 100 consecutive patients with biopsy-proven giant cell arteritis diagnosed in two Australian hospitals between 1988 and 1998. Among 67 patients who met inclusion criteria for ION in GCA, seven patients had recurrent ION. We compared the seven patients with recurrent ION to the 60 patients with nonrecurrent ION in terms of age, gender, mode of corticosteroid delivery, initial visual acuity in the affected eye, prevalence of bilateral ION, initial erythrocyte sedimentation rate (ESR) level, and rate of corticosteroid dose reduction. In the recurrent ION group, we documented the timing of the recurrence in relation to corticosteroid dose, elevation in acute phase reactants, and relapse of systemic symptoms. We found recurrent ION in GCA in 10% of our cohort, higher than has been previously reported. Recurrences, all of which were ipsilateral, occurred from 3 to 36 months (median 8 months) after the initial ION. None of the clinical indicators the authors examined differed between the two groups. Six of seven patients with recurrent ION had elevations in ESR or C-reactive protein or a new headache at the time of ION recurrence, but in only one of these patients were these features recognized as preceding the recurrent ION. One patient had neither an elevation in acute phase reactants nor a relapse in systemic symptoms of GCA at the time of ION recurrence. Recurrent ION in GCA is difficult to predict. Although elevated acute phase reactants or new systemic symptoms consistent with GCA were present in six (83%) of our patients with ION recurrence, in only one patient (17%) did these events occur with enough lead time to allow caregivers to act preemptively. Thus, even very close monitoring of GCA patients with ION may not predict ION recurrence.

Effects Of Alum On The Quality Of Aquaculture Effluents In Settling Ponds

The effectiveness of alum (aluminum sulfate) in reducing the concentrations of potential pollu- tants in pond effluents was investigated in catfish production ponds. Application of alum at 50 mg/l to water remaining in ponds immediately after seining for harvest did not generally result in significantly greater removal of nutrients and solids than did settling alone, although removal rates of some variables were initially higher in the alum treated ponds. Within four hours of sein- ing in both alum treated and untreated ponds, there was removal of more than 85% of total sus- pended solids, 75% of total phosphorus, 72% of turbidity, and more than 40% of biochemical oxygen demand and chemical oxygen demand. Concentrations of soluble reactive phosphorus decreased after 48 h, but total ammonia nitrogen was not removed. Alum may be more effective in improving water quality in settling ponds if it is applied after the initial sedimentation has occurred.

Late Quaternary stratigraphy and geochronology of the western Killpecker Dunes, Wyoming, USA

New stratigraphic and geochronologic data from the Killpecker Dunes in southwestern Wyoming facilitate a more precise understanding of the dune field’s history. Prior investigations suggested that evidence for late Pleistocene eolian activity in the dune field was lacking. However, luminescence ages from eolian sand of ∼15,000 yr, as well as Folsom (12,950–11,950 cal yr B.P.) and Agate Basin (12,600–10,700 cal yr) artifacts overlying eolian sand, indicate the dune field existed at least during the latest Pleistocene, with initial eolian sedimentation probably occurring under a dry periglacial climate. The period between ∼13,000 and 8900 cal yr B.P. was characterized by relatively slow eolian sedimentation concomitant with soil formation. Erosion occurred between ∼8182 and 6600 cal yr B.P. on the upwind region of the dune field, followed by relative stability and soil formation between ∼5900 and 2700 cal yr B.P. The first of at least two latest Holocene episodes of eolian sedimentation occurred between ∼2000 and 1500 yr, followed by a brief (∼500 yr) episode of soil formation; a second episode of sedimentation, occurring by at least ∼700 yr, may coincide with a hypothesized Medieval warm period. Recent stabilization of the western Killpecker Dunes likely occurred during the Little Ice Age (∼350–100 yr B.P.). The eolian chronology of the western Killpecker Dunes correlates reasonably well with those of other major dune fields in the Wyoming Basin, suggesting that dune field reactivation resulted primarily due to departures toward aridity during the late Quaternary. Similar to dune fields on the central Great Plains, dune fields in the Wyoming Basin have been active under a periglacial climate during the late Pleistocene, as well as under near-modern conditions during the latest Holocene.

The influence of blood transfusion on survival in operated non–small cell lung cancer patients

BackgroundIt has been postulated that allogeneic transfusions have immunosuppressive effects that can promote tumor growth and metastasis formation. Despite the variety of publications on this controversial topic, the influence of blood transfusion on survival is not yet clearly identified. The impact of autologous blood transfusion on survival has only occasionally been analyzed in cancer patients. ObjectiveTo determine the effect of perioperative allogeneic and autologous blood transfusions on survival in non–small cell lung cancer patients treated with curative pulmonary resection. MethodsOf 493 consecutive patients, 185 (37.5%) received allogeneic blood products and 145 (29.4%) received autologous blood products, whereas 163 patients (33.1%) received no blood products. Survival analysis included univariate log-rank test and multivariate Cox regression model. ResultsThree-year survival probabilities in allogeneic, autologous, and nontransfused groups were 40%, 48%, and 61%, respectively, and the estimated 5-year survival probabilities were 34%, 38%, and 48%, respectively. In the univariate analysis there was a reduced survival in allogeneic versus nontransfused group (P < .01). In the multivariate analysis stage (P < .01), initial hemoglobin level (P = .01) and sedimentation rate (P = .03) remained significant factors, whereas the type of blood transfusion (allogeneic versus autologous) was no longer significant. There was no significant impact of transfusion in the multivariate analysis when patients in stage III or patients who underwent pneumonectomy were excluded. ConclusionNeither allogeneic nor autologous blood transfusion has independent, adverse survival impact in non–small cell lung cancer patients treated with radical pulmonary resection.

Features of some Early-Middle Jurassic diastems in Bulgaria

Almost all studied here diastems are situated in the Western Balkanids, and only one is in the Central Forebalkan. They are differentiated in two groups. The first group encloses diastems with cover represented by the deep water micritic limestones of the Yavorets Formation in which exist more or less shallow-water elements. Some of them are exotic in the low-energy textures (the localities near the town of Belogradchik and by the Ledenika Cave, Vratsa District). The faunal spectra indicate conditions of the deep subtidal - depths about 100-200m. The second group unify diastems created by marine transgressions which were not accompanied by sedimentation. The latter began with delay in the course of deepening of the basin (the localities Desivichki Dol and the village of Mitrovtsi, Montana District, as well as the village of Glozhene, Teteven District and probably the village of Zgorigrad, Vratsa District). In connection to the different regimes in sedimentation, as a result of marine transgressions and the deepening of the sea-basin, we introduce here some new terms for the different types of sediments. We name syntransgressive sediments those that have accompanied the marine transgressions. They are covered by the posttransgressive sediments, deposited with the deepening of the basin. When the marine transgression is not accompanied by sedimentation and the first sediments have been deposited with the deepening of the basin, these sediments are called initial posttransgressive sediments. The localities or areas with initial postransgressive sedimentation possessed a positive relief and resulted in formation of diastems. Their basements always are older than the Jurassic and usually are covered by hardgrounds. The significance of such type of diastems is bigger than has been regarded in the past.

Large‐scale seabed dynamics in offshore morphology: Modeling human intervention

We extend the class of simple offshore models that describe large‐scale bed evolution in shallow shelf seas. In such seas, shallow water flow interacts with the seabed through bed load and suspended load transport. For arbitrary topographies of small amplitude we derive general bed evolution equations. The initial topographic impulse response (initial sedimentation and erosion patterns around an isolated feature on a flat seabed) provides analytical expressions that provide insight into the inherent instability of the flat seabed, the Coriolis‐induced preference for cyclonically oriented features, and bed load transport being a limiting case of suspended load transport. The general evolution equation can be used to describe sandbank formation, known as the result of self‐organization. Examples of human intervention at the seabed include applications to a dredged channel and an offshore sandpit. An outlook toward future research is also presented.

Araçatuba Formation: palustrine deposits from the initial sedimentation phase of the Bauru Basin

The Bauru Basin (Upper Cretaceous) accumulated an essentially sandy continental sedimentary sequence. In a first desertic phase the basaltic substratum was covered by a widespread and homogeneous aeolian sand unit with minor loess intercalations. The substratum relief favored the formation of an endorheic drainage system under semi-arid climate, a process that started the development of the Araçatuba Paleoswamp. The palustrine deposits (Araçatuba Formation) comprise siltstone and tipically greenish gray narrow tabular strata of sandstone cemented by carbonate. Moulds and gypsite and dolomite pseudomorphs were identified. The moulds seem to be genetically associated with desiccation cracks, root marks and climbing ripple lamination levels, that, on the whole, indicate calm shallow saline waters undergoing phases of subaerial exposition. At the boundaries of the study area, sand units may exhibit sigmoidal features and convolute bedding structure, which is characteristic of marginal deltaic deposits. The Araçatuba Formation is enclosed in and later overlaid by the aeolian deposits of the Vale do Rio do Peixe Formation.

TUNNEL VALLEYS AND DENSITY FLOW PROCESSES IN THE UPPER ORDOVICIAN GLACIAL SUCCESSION, ILLIZI BASIN, ALGERIA: INFLUENCE ON RESERVOIR QUALITY

Upper Ordovician syn‐glacial deposits form a gas reservoir at the Tiguentourine field, Illizi Basin, Algeria. The reservoir geology of these glacial deposits has been investigated with the objective of understanding the widely varying thickness of the sequence and the controls on reservoir quality.A general depositional model was developed following a review of outcrops in the Tassili N'Ajjer region, some 200km south of Tiguentourine. In these outcrops, elongate tunnel valleys were observed to be incised into the subglacial surface, and these were interpreted to have been formed by subglacial meltwater flows. The isopach map of the Tiguentourine field syn‐glacial sequence, derived from well penetrations and a 3D seismic survey, indicates there were two elongate depressions analogous to, but broader than, the tunnel valleys observed at outcrop.The sedimentary rocks encountered at outcrop and in the subsurface were broadly similar. Initial sedimentation in the tunnel valleys typically comprised medium‐ to coarsegrained, structured sandstones. These were interpreted as the deposits of glaciofluvial currents flowing along the tunnel valleys. They were succeeded by a range of density flow deposits (muddy and sandy debrites, high‐ and low‐density turbidites). In the outcrops, the turbidites are seen to evolve upwards from an amalgamated sheet complex to sinuous channel forms. Long wavelength (&gt;2m), low amplitude, symmetrical dunes were noted in these high‐density turbidites; they were interpreted to be the products of sustained, possibly hyperpycnal, turbidity currents. In the subsurface, pelagic deposits with graptolites were recorded towards the top of the succession indicating a glacial‐marine environment. At its maximum extent, the ice is believed to have been grounded on the continental shelf. The synglacial succession in the south Illizi Basin was interpreted as a product of glacial retreat, with the hardground at the top of the sequence probably the result of isostatic uplift.

Survival in polymyalgia rheumatica and temporal arteritis: a study of 398 cases and matched population controls.

To estimate survival in polymyalgia rheumatica (PMR) and temporal arteritis (TA). The present study encompassed 338 incident cases who were diagnosed at the Department of Rheumatology during the period 1987-1997 and 60 cases diagnosed in the same period but admitted to hospital for reasons other than PMR or TA. The 398 patients were each assigned four age- and sex-matched controls from the same population and mortality ascertained. Among the 338 incident cases, there were 69 deaths compared with 360 deaths among their 1352 controls. The mortality was thus 28% lower in cases than in controls [relative risk (RR)=0.72, 95% confidence interval (CI) 0.55-0.95]. The 274 incident cases with pure PMR had increased survival compared with controls (RR=0.70, 95% CI 0.52-0.95), whilst among the 64 incident TA patients and their controls, no difference in mortality was found (RR=1.2, 95% CI 0.55-2.74). Patients diagnosed at other departments and their controls had the same mortality. In the incident cases, the mean initial dose of prednisolone, the mean maintenance dose of prednisolone, the mean initial erythrocyte sedimentation rate and C-reactive protein and frequency of peripheral arthritis did not differ between survivors and those dying during the observation period. The study showed increased survival in patients with PMR compared with controls, whilst mortality in TA equalled that of controls. There was no association between use of corticosteroids and level of disease activity and death. The increased survival in PMR might be explained by improved medical surveillance.

Tectono-sedimentary evolution of sedimentary basins from Late Paleoproterozoic to Late Neoproterozoic in the São Francisco craton and Araçuaı́ fold belt, eastern Brazil

Two first-order regional unconformities separate Proterozoic supracrustal rocks of the São Francisco craton and the Araçuaı́ fold belt (eastern Brazil) into three genetic units. These constitute three superimposed first-order basin-fill cycles: the Espinhaço, Macaúbas-Salinas and Bambuı́ megasequences. The Paleo-Mesoproterozoic Espinhaço megasequence (ca. 1730–1500 Ma) was deposited in an intracratonic rift-sag basin in four stages (pre-rift, rift, transitional and flexural). Each of these stages is bounded by regional, second-order unconformities. Basin evolution was controlled primarily by tectonics, although sea-level variations were also important in the transitional and flexural stages. After a hiatus of several hundred million years, subsidence renewed during extension related to the early Neoproterozoic breakup of the supercontinent Rodinia with rift to passive-margin sedimentation in the Macaúbas-Salinas Basin (ca. 950–700 Ma). Initial glaciogenic sedimentation, possibly induced by uplift related to a mantle plume, occurred in a rift setting. Subsequent a shelf/slope/deep-sea passive-margin deposits, represent opening of a northern branch of the Adamastor Ocean. Tectonic, magmatic, climatic and eustatic processes all combined to control basin evolution. The Bambuı́ megasequence (ca. 800–650 Ma) was deposited in a foreland basin during convergent and collisional tectonics related to closure of the Brazilide Ocean and generation of the Brası́lia fold belt west of the São Francisco paleocontinental region. The evolution of the Bambuı́ Basin, whose fill is characterized by three transgressive–progradational, shallowing–upward sequences, was mainly controlled by tectonic processes.