Late Episodes Research Articles

Carbonate deposition in accretionary prism settings: Early miocene coral limestones and corals of the Makran mountain range in Southern Iran

The regional mapping of the Makran mountain range on behalf of the Geological Survey of Iran represents a unique coverage: the entire area of the mountain range was compiled in a unified programme. During this mapping, Miocene limestones containing rich coral and foraminiferal faunas were recorded over a strike length of several hundred kilometres, as minor developments within thick neritic clastic sequences which in turn overlie great thicknesses of Eocene-Miocene flysch. These limestones include rigid bioconstructional frame-works, loosely compacted coralline assemblages and foraminiferal calcarenites: they includein situ recfal deposits and material redeposited quite close to their original site of deposition. Most are Burdigalian, as shown by the benthonic foraminifera, but some are Aquitanian. The geotectonic setting was an accretionary prism in a zone of plate convergence. The limestones and enclosing clastic sediments comprise an intensely folded, reverse-faulted and locally dislocated sequence, the duplex structure being the result of a major Late Miocene-Pliocene episode of regional deformation. This concentration of the intense tectonic deformation in a late major episode requires a different model for this zone of plate convergence to the model widely applied to such zones. The possible controls on limestone deposition are discussed-tectonic uplift and shallowing of the sea, climatic warming and eustatic factors. Depositional features of reefal formations in the late Jurassic of the Caucasus, the Pliocene-Recent of Halmahera, and the early Miocene of SE France are discussed in comparison with the Makran model.

Late Nineteenth-Century Anglo-American Factor-Price Convergence: Were Heckscher and Ohlin Right?

Due primarily to transport improvements, commodity prices in Britain and the United States tended to converge between 1870 and 1913. Heckscher and Ohlin, writing in 1919 and 1924, thought that these events should have contributed to factor-price convergence. It turns out that Heckscher and Ohlin were right: a significant share of the Anglo-American real-wage convergence was due to commodity-price convergence. It appears that this late nineteenth-century episode was the dramatic start of world-commodity and factor-market integration that continues today.

Paleozoic Plate-Tectonic Evolution of the Tarim and Western Tianshan Regions, Western China

The plate-tectonic evolution of the Tarim basin and nearby western Tianshan region during Paleozoic time is reconstructed in an effort to further constrain the tectonic evolution of Central Asia, providing insights into the formation and distribution of oil and gas resources. The Tarim plate developed from continental rifting that progressed during early Paleozoic time into a passive continental margin. The Yili terrane (central Tianshan) broke away from the present eastern part of Tarim and became a microcontinent located somewhere between the Junggar ocean and the southern Tianshan ocean. The southern Tianshan ocean, between the Tarim craton and the Yili terrane, was subducting beneath the Yili terrane from Silurian to Devonian time. During the Late Devonian-Early Carboniferous, the Tarim plate collided with the Yili terrane by sinistral accretional docking that resulted in a late Paleozoic deformational episode. Intracontinental shortening (A-type subduction) continued through the Permian with the crea...

Experience with the Mitroflow aortic bioprosthesis

From October 1985 to May 1990, the Mitroflow bovine pericardial valve was placed in the aortic position in 168 patients (97 men, 71 women) with a mean age of 69.7 years. Eighty-nine patients had isolated aortic valve replacement, and 79 had aortic valve replacement and additional procedures. Follow-up over 7½ years includes 781 patient years (426 for isolated aortic valve replacement). Mean follow-up time is 56 months. Peak-to-peak gradients (in millimeters of mercury) measured in the intraoperative period averaged 11.0 ± 8.7, 11.8 ± 10.8, and 8.6 ± 8.2 for 19 mm, 21 mm, and 23 mm valves, respectively. Hospital mortality was 7.3% (14 patients); all deaths were non-valve related. Late mortality of 20.1% in 31 patients resulted from cardiac failure ( n = 8), sepsis ( n = 4), valve reoperation ( n = 1), non-cardiac causes ( n = 15) and sudden, unknown causes ( n = 3). Fifteen thromboembolic episodes occurred, but only three late thromboembolic episodes occurred in isolated aortic valve replacement without other risk factors. Four early and four late episodes of endocarditis occurred. Seven patients had clinical valve dysfunction, and five others required reoperation for structural deterioration, with one death. At 94 months, overall survival was 64% ± 5%. Freedom from thromboembolic episode was 87% ± 3% and 90% ± 4% for isolated aortic valve replacement. Freedom from combined reoperation or clinical dysfunction was 75% ± 8%: 64% ± 15% for those under 70 years of age, and 87% ± 7% for those 70 years of age and older. The valve has favorable hemodynamics. Durability begins to decline during the sixth year after implantation, possibly at a slower rate in patients older than 70 years of age. (J THORAC CARDIOVASC SURG 1994;108:215-20)

On late miocene to recent vertical motions in the Cretan segment of the Hellenic arc

High-resolution foraminiferal and calcareous nannoplankton biostratigraphy and reliable paleobathymetry estimates based on plankton-benthos ratios in foraminifera make it possible to reconstruct in detail Late Neogene vertical motions along the Central Cretan segment of the Hellenic arc. These motions are considered to express the surficial effect of the roll-back process of the Hellenic subduction zone, which started about 12 Ma ago. In contrast to earlier views there is no sustained uplift since the late Middle Miocene. Successive paleotopographic profiles for central Crete show a predominance of subsidence, coupled with an increase of differential reliefs, from the latest Serravallian until the Messinian. Subsidence was most pronounced between the Tortonian-Messinian boundary interval and the early part of the Early Pliocene, locally up to a magnitude of more than 1000 m. A two-phased uplift history, coupled with tilting to the north or northeast, can be inferred from the late Early Pliocene-Recent record separated by a short, early Late Pliocene episode of subsidence. Rates of uplift were highest in the Early Pliocene up to about 125 cm/ka. The Central Cretan Late Neogene to Recent paleotopographic profiles are compared with those reconstructed from seismic interpretations and drilling data from the Cretan Sea. The combined results show that paleotopographic configurations between the Cyclades and Crete were fairly similar to those on central Crete until Messinian time. Foundering of the Cretan Basin started in the course of the Early Pliocene, but subsidence rates were less than the contemporaneous uplift rates of Crete. The timing and magnitude of the vertical motions along the Cretan Sea-Central Cretan transect put detailed geological constraints on tectonophysical modelling of the surficial effects of the roll-back process. These vertical motions are discussed in view of the model of southward translation of a large supracrustal slab, resulting in the origin of the Cretan Sea and in thrusting and uplift in the frontal parts of the slab, where it thrusted over the northern limb of the subducted Ionian Plate.

Mating success in brood-guarding male rock bass,Ambloplites rupestris: the effect of body size

The hypothesis that variation in a paternal trait associated with offspring survival will result in female mate choice based on that trait was tested in rock bass,Ambloplites rupestris, a temperate fresh water fish with uniparental male care. The number of eggs acquired by 108 nesting male rock bass, in Cranberry Lake (New York State, U.S.A.), was estimated in two different spawning episodes that differed in the size structure of the nesting male stock. Early breeders (between the 4–7 June 1989) were mainly medium and large males (101–300 g), as compared to late breeders (between the 19–21 June 1989) which were mostly small (50–100 g). Because survival of larvae in rock bass is significantly lower in nests guarded by small males as compared to nests guarded by medium and large males, it was hypothesized that female mate choice should have been (1) size-based, and (2) more intense late in the season when the nesting stock was comprised mostly of small males. The results were consistent with these hypotheses. Variation in egg numbers per nest was significantly higher during the late spawning episode. In addition, egg number per nest were normally distributed during the early spawning episode, but were positively skewed and leptokurtic during the later episode. The correlation between male size and egg number was significant for both spawning episodes. However, during the late episode male size explained 23% of the variation in egg numbers versus only 8% of the variation during the earlier episode.

Archaeology and holocene sand dune stratigraphy on Chatham Island

Four depositional episodes based on sand deposits and the soils on them are proposed for Holocene coastal sand dunes on Chatham Island: Te Onean Depositional Episode (c. 5,000 to 2,200 years BP), Okawan Depositional Episode (c. 2,200 to 450 years BP), Kekerionean Depositional Episode (c. 450 to 150 years BP) and Waitangian Depositional Episode (c. 150 years BP to present day). Each depositional episode has two phases: an unstable phase with a high rate of deposition and no soil formation, followed by a stable phase with a low rate of deposition and soil formation. The Okawan, Kekerionean, and Waitangian episodes closely match late Holocene depositional episodes on the New Zealand mainland. The earliest human occupation remains (Moriori) are in Kekerionean sands and the inferred date for Moriori settlement of Chatham Island is between 400 and 450 years BP. Bones of Hooker's sea lion are found in Te Onean and Okawan deposits. The most recent bones are in Kekerionean middens and it is inferred that Hooker's sea lion was driven from the Chatham Islands by human predation. The depositional episodes appear to be unrelated to sea level changes, tectonic activity, or cultural influence. It is suggested that they may be related to coastal erosion initiated by storms.

Late Oligocene-Early Miocene compressional tectosedimentary episode and associated land-mammal faunas in the Andes of central Chile and adjacent Argentina (32–37°s)

A reassessment of the geologic and land-mammal fossil evidence used in attribution of a tectosedimentary episode in the Andes between 32 and 37°S to the Middle Eocene “Incaic tectonic phase” of Peru indicates that the episode occurred during Late Oligocene-Early Miocene times(~ 27-20 Ma). From west to east, three structural domains are recognized for this time span in the study area: a volcanic arc (Chile); a thin-skinned, E-verging fold-thrust belt (Cordillera Principal, Chile-Argentina border strip); and a foreland basin (Argentina). Initiation of thrusting in the Cordillera Principal fold-thrust belt produced the coeval initiation of sedimentation in the foreland basin of adjacent Argentina. This onset of foreland deposition postdates strata bearing a Divisaderan Land Mammal Age fauna (i.e. ~ 35-30 Ma) and is marked at ~ 36°30′S by the base of the “Rodados Lustrosos” conglomerates, which are conformably overlain by sedimentary rocks containing a Deseadan Land Mammal Age fauna (i.e. ~ 29-21 Ma). Geologic relationships between the thick volcanic Abanico (Coya-Machalí) and Farellones formations also demonstrate that this tectosedimentary episode practically ended at ~ 20 Ma at least in the volcanic arc, and was therefore roughly coeval with the major tectonic crisis (~ 27-19 Ma) known in northwestern Andean Bolivia some 1500 km to the north. This strongly suggests that a long, outstanding tectonic upheaval affected at least an extended 12–37°S segment of the Andean margin of South America during Late Oligocene and Early Miocene times.

Controls on Reservoir Development in a Shelf Carbonate: Upper Jurassic Smackover Formation of Alabama

Hydrocarbon reservoirs of the Upper Jurassic Smackover Formation in Alabama are predominately oolitic and pelletal dolostone. Pore systems are dominated by moldic and secondary intraparticle pores, intercrystalline pores, or mixtures of these pore types. All Smackover reservoirs in Alabama have been strongly affected by early cementation, dissolution of calcium-carbonate allochems, and dolomitization. Marine-phreatic cement occluded primary interparticle porosity in much of the Smackover reservoirs in Alabama. Dolomitization of the Smackover in Alabama included penecontemporaneous, early burial, and late (deep) burial episodes. Early burial dolomite predominates. Fabric-selective dolomitization yielded reservoirs strongly influenced by both depositional fabric and diagene is. Nonselective dolomitization yielded reservoirs with intercrystalline pore systems shaped primarily by diagenesis. Porosity evolution was controlled regionally by level of thermal exposure, mode of dolomitization, and proximity to the Wiggins arch. Thermal exposure is inversely related to porosity, but the relationship is weak (r2 < 0.5). Fabric-selective dolostone is slightly more porous than nonselective dolostone when averaged over the entire study area (averages of 18.1% and 15.1%, respectively; p = 0.0001), but nonselective dolostone is more porous at a given level of equivalent vitrinite reflectance. Smackover fields on the north flank of the Wiggins arch are unusually porous given their level of thermal maturity, and are unusual in other ways as well. Local porosity variation was controlled by depositional fabric, early cementation, dissolution, and burial compaction and cemen ation. Regional permeability variation cannot be explained using existing data. Permeability is locally controlled by pore-throat size, the effects of dolomite crystal-size distribution, early cementation, fracturing, and burial compaction and cementation. Pore-throat size exhibits the strongest overall correlation with permeability (r2 = 0.54). Permeability and porosity are strongly correlated locally, but the regional correlation is weak.

Urolase laser prostatectomy in patients on warfarin anticoagulation: A safe treatment alternative for bladder outlet obstruction

Three patients with symptomatic bladder outlet obstruction due to benign prostatic hyperplasia underwent laser prostatectomy using a Neodymium:YAG source delivered with the Urolase right-angle laser fiber. All patients had significant underlying medical problems, and all were fully anticoagulated with oral warfarin (mean prothrombin time 17 seconds). Two were in urinary retention with indwelling catheters preoperatively. Laser prostatectomy was performed in each case without change in the medical regimen, including continuous warfarin dosing. No complications occurred, and in particular, no early or late bleeding episodes were encountered. All are symptomatically improved and catheter-free on follow-up. Laser prostatectomy provides a new and safe therapeutic option in the management of these high-risk patients.

Fission-track dating of 15 macusanite glass pebbles from the Macusani volcanic field (SE Peru)

We dated, by fission tracks, 15 Macusanites from four sites located inside or in the vicinity of the Macusani ignimbritic field. Eight of these obsidian pebbles are from the new site of Chilcuno Grande, the remaining seven from the three sites of Caluyo Mayo, Chilcuno Chico and Samillia. The apparent fission-track ages of these obsidians range from about 4.6 to 3.2 Ma. As in all samples, fossil tracks show evidences of annealing; the apparent ages are only lower estimates of Macusanite formation time. Fission-track plateau ages could be determined in 12 samples. They range between 7.9 and 4.8 Ma. The distribution of available plateau ages suggests that Macusanites formed both during the main activity of the Macusani volcanic field (7 ± 1 MA ago) and late episodes (5.7−5.3 and 4.8−4.3 Ma ago).

Prophylactic Myocardial Revascularization Based on Dipyridamole-Thallium Scanning before Peripheral Vascular Surgery

Cardiac events continue to be the leading cause of perioperative mortality following peripheral vascular reconstruction. The role of preoperative cardiac screening and prophylactic myocardial revascularization in patients without clinical evidence of coronary artery disease is undefined. Fifteen patients with no clinical evidence of coronary artery disease who were found to have reversible defects on dipyridamole-thallium scans and severe correctable coronary artery disease underwent aortocoronary artery bypass grafting. There was one (6.7%) operative death. Three patients (20%) developed postoperative complications: two atrial fibrillation and one breakdown of the saphenous vein harvest site. Thirteen patients underwent subsequent peripheral vascular surgery: seven had abdominal aortic procedures, three infrainguinal reconstruction, two carotid endarterectomy and one carotid-subclavian artery bypass. There were no perioperative or late deaths, cardiac complication, electrocardiographic changes, or episodes of angina associated with the peripheral vascular procedures. Thus, dipyridamole-thallium imaging appears to help select a group of symptom-free, but high cardiac risk, vascular patients in whom preparatory myocardial revascularization and subsequent peripheral vascular surgery can be performed with acceptable mortality and morbidity. The life expectancy of these patients may be improved and, specifically, the risk of their subsequent vascular surgery may be reduced by this approach.

The Pre‐Cenozoic magmatic history of the Thurston Island Crustal Block, west Antarctica

New Rb‐Sr and K‐Ar geochronological data are presented for the majority of known pre‐Cenozoic outcrops in Thurston Island, the Jones Mountains, and the western Eights Coast, which collectively represent the basement geology of the Thurston Island crustal block of West Antarctica. Almost all are of calc‐alkaline igneous or metaigneous rocks, and indicate long‐standing proximity to a magmatic arc. The observable history began with Late Carboniferous (309±5 Ma) emplacement of mantle‐derived orthogneiss precursors in eastern Thurston Island. Nd model ages from these and later igneous rocks suggest that the underlying crust is no older than about 1200–1400 Ma throughout the area. A variety of cumulate gabbros was emplaced soon after gneiss formation, followed by crust‐contaminated diorites that have Triassic mineral cooling dates of 240–220 Ma. In the nearby Jones Mountains, the oldest exposed rock is a muscovite‐bearing granite with an Early Jurassic age of 198±2 Ma; its initial 87Sr/86Sr ratio of 0.710 and ϵNdt values of −5 to −7 indicate either anatexis or, at least, a high degree of crustal input during magma genesis. This belongs to a suite of such granites known throughout the Antarctic Peninsula and related to earliest rifting of the Gondwana supercontinent. The subsequent evolution of the Thurston Island area was dominated by I‐type magmatism, apparently in two major episodes at 152–142 Ma (Late Jurassic granites) and 125–110 Ma (Early Cretaceous bimodal suite). Most of these magmas had initial 87Sr/86Sr ratios of 0.705–0.706 and ϵNdt values of +2 to −4 and were derived from slightly enriched mantle or from juvenile lower crust. They are thought to signify subduction of Pacific Ocean floor as in the adjacent parts of West Antarctica, although the Late Jurassic episode was of greater intensity in Thurston Island than elsewhere. The Cretaceous magmatism was intense and of Andean‐type. Between 100 and 90 Ma, volcanism in the Jones Mountains became predominantly silicic, with increasing incorporation of crustal components (initial 87Sr/86Sr ratios of 0.706–0.709 and ϵNdt values of −3 to −6), as subduction‐related magmatism ceased in this part of the margin.

Mantle‐derived heat recorded by conodont colour alteration in the Carboniferous of the Isle of Man

AbstractA range of colour alteration index (CAI) values between 3.0 and 6.0 is recorded for conodont elements recovered from the Arundian to Brigantian (Dinantian, Lower Carboniferous) sequence around Castletown, Isle of Man. Mantle‐derived heat, channelled through the Caledonian South Barrule pluton, is proposed as the major cause of these elevated values. A lower CAI of 2.5 is obtained from elements recovered from a borehole sunk into the concealed Namurian (Upper Carboniferous) deposits near Shellag Point; the Glen Mona pluton acted as the medium for mantle‐derived heat in this instance. The CAI values which may have been established during a late Dinantian volcanic episode around Castletown were overprinted by the greater effects of heat emanating from the South Barrule pluton. The record of CAI 6.0 for a sample taken from the immediate vicinity of a dyke indicates a high level of very localized CAI elevation in the early Tertiary.

The timing of Ordovician magmatism in the English Lake District and Cross Fell inliers

AbstractVolcanic and hypabyssal intrusive rocks of the Lower Palaeozoic English Lake District and Cross Fell inliers are elements of the Ordovician destructive plate margin system of microcontinental Avalonia. Two igneous sheets within the marine sedimentary Skiddaw Group of these inliers, previously described as lavas, are reinterpreted as sills. Sedimentary rocks enclosing these sills are of late Tremadoc-early Arenig (c. 493 Ma) and early Llanvirn (&gt; 476 Ma) age, and breccias along the upper contacts of both were produced by steam explosivity and fluidization ahead of theadvancing tips of the intrusions. Previous interpretation of the breccias on the older sheet, as sediment deposited on the eroded top of a lava flow, implied an early Ordovician onset of arc magmatism. Such early magmatism would have been virtually coincident with the latest Tremadoc initiation of arc magmatism in Wales, but evidence for such a near synchronous response tothe putative onset of subduction is lacking. Respective onsets of magmatismwere probably separated by at least 17 m.y., and possibly by as much as 29 m.y. The apparent contemporaneity of mid and late Ordovician volcanic episodes in England and Wales, and similarities in extensional tectonic style, suggest that the two areas then were part of the same subduction system responding similarly to plate-scale magma-generating and tectonic processes. The early Ordovician situation is uncertain, but the absence of arc volcanic rocks of this age in the English Lake District suggests that this area and Wales are not tectonically juxtaposed elements of a former simple linear arc.

Tertiary tectonic evolution along the Arne‐Elin Trend in the Danish Central Trough

Tertiary sequence boundaries are mapped on reflection seismic sections in the northern part of the Danish Central Trough, North Sea. The geometry of the sequence boundaries and the isopach maps of the sequences are used as indicators of differential subsidence.The Tertiary tectonic evolution is subdivided into: (i) Late Palaeocene and Early Oligocene episodes of inversion along the NNW–SSE striking Arne–Elin Trend (ii) Early Oligocene to Pliocene episodes of differential subsidence across pre‐Tertiary fault trends.The observed differential subsidence and inversion is related to pre‐Tertiary faults and fault trends, and dating of the sequences shows that the tectonic phases were contemporaneous with tectonic events in NW Europe. It is suggested that the differential subsidence‐inversion is controlled by reactivation of pre‐Tertiary faults/fault‐trends by block movements due to an interaction of the Alpine collision and the opening of the Atlantic.

Palynological evidence for late quaternary warming episodes in Southern Africa

Polleniferous sediments from southern Africa associated with past warm episodes before the Last Glacial Maximum, are rare. Interpretation of environmental conditions during these phases are complicated by difficulties of dating. In sediments from the northern areas, north of 28°S, the prominence of tropical woodland pollen suggests that the period between 7000 and 6500 yr B.P. was associated with optimal temperatures during the Holocene. Identifying the warmest phase in the southern high-lying grasslands and semi-arid Karoo shrublands south of 28°S is difficult, because unlike the savanna areas of the north, they do not yield good pollen indicators for changes in temperature such as those of frost sensitive trees. However, some pollen sequences from further south along the southern coast of Africa (34°S) and at Marion Island in the Southern Ocean (47°S), suggest that the Holocene temperature optimum occurred at about the same time in the sub-antarctic area in the south and the subtropical regions in the north. The advent of moister conditions in southern Africa during the early to middle Holocene, is generally recorded earlier (ca. 7500-6500 yr B.P.) in the north at ca. 26°S, than around 31°S, (ca. 5000 yr B.P.). This change is provisionally associated with a relative shift in seasonality from a predominance of all-season precipitation to a greater proportion of summer rainfall, which apparently reached the southern Karoo areas two thousand years later than the northern Bushveld region.

Evaluation studies with a regional chemical transport model (EURAD) using air quality data from the EMEP monitoring network

Abstract The EURAD model has been applied to simulate the transport and chemical transformations of atmospheric constituents over central Europe for a 3 week late winter episode in February/March 1982. The TADAP model (the European version of ADOM) carried out simulations for the same episode with the same emission data set but with different meteorological input. The episode is characterized by two typical European meteorological conditions: a relatively quiet blocking situation at the beginning of the episode is followed by rather disturbed conditions with frontal systems passing through central European. The evolution of the pollutant fields is markedly different during these two conditions. Evaluation studies with the focus on the sulfur species were performed using air quality data from the EMEP monitoring network for the comparison of model predictions with observations. The first simulation with predicted meteorology and the PHOXA emission data set revealed an underprediction of airborne sulfate and wet deposition, while SO 2 was overpredicted. A simulation with meteorological data created by a so-called nudging technique corrected the transport of SO 2 to remote regions and drastically improved the predictions of rainfall and subsequently the amount of wet deposition. However, the ambient sulfate aerosol concentrations were still underpredicted. As the same bias in sulfate was also observed for TADAP simulations of the same episode a hypothesis for the underprediction is a very low primary sulfate emission inherent in the emission database. By artificially increasing the primary sulfate emission to an obviously too high value, the underprediction of sulfate was changed into a strong overprediction for the major source regions and into a reasonable range as observed for the remote regions. An analysis of the precipitation amounts, the aqueous concentrations and the resulting wet deposition showed that during this episode the aqueous were precipitation limited.

Tapering or Discontinuing Cyclosporine for Financial Reasons—A Single-Center Experience

In patients with primary cadaveric renal transplants and stable allograft function, we assessed the impact of tapering or discontinuing cyclosporine A (CsA) for financial reasons. Forty-two patients whose CsA was discontinued ("no-dose") and 29 patients whose CsA was tapered to 100 to 150 mg/d ("low-dose"; mean, 1.7 mg/kg/d) were examined. Results were compared with 70 age- and race-matched control patients maintained on at least 200 mg/d of CsA (mean, 3.9 mg/kg/d). Follow-up time for all patients averaged 55 +/- 18 months. Late acute rejection episodes occurred more frequently in no-dose than in low-dose (P = 0.017) or control (P = 0.001) patients. In the no-dose group, blacks experienced a greater number of late acute rejections than whites. These late acute rejections often coincided with the discontinuation of CsA and contributed to an increased rate of allograft loss in blacks in the no-dose group compared with black and white controls (P = 0.011). In contrast, no increase in late acute rejection episodes occurred in blacks tapered to low doses of CsA. Black patients who remained on low doses of CsA also exhibited a trend toward allograft survival that was intermediate between that of control and no-dose patients. In those patients who retained functional allografts, mean serum creatinine concentration did not differ between the study groups at the beginning and end of the follow-up period. These findings support continuance of CsA in black primary cadaveric renal transplant patients, even if dosages must be reduced to 100 to 150 mg/d.(ABSTRACT TRUNCATED AT 250 WORDS)

Anoxic events in the late Frasnian—Causes of the Frasnian-Famennian faunal crisis?

Carbon isotope data collected from five Frasnian-Famennian boundary sections in central Europe show two positive δ 13 C excursions in the late Frasnian (∼367 Ma). Both anomalies coincided with the deposition of the bituminous lower and upper Kellwasser horizons. The carbon isotope patterns indicate two phases of enhanced burial and subsequent recycling of organic carbon. A maximum formation of warm saline waters on the subtropical to tropical epicontinental shelves during late Frasnian transgressive episodes may have induced oceanic oxygen deficits. Variations in the C org burial rates may have resulted in changes in the CO 2 concentrations in the oceans and in the atmosphere, culminating in global climatic changes. We propose that the repeated co-occurrences of sea-level fluctuations, anoxic conditions, and global climatic changes during the late Frasnian would affect especially the subtropical to tropical shallow-water communities and reef ecosystems, which were severely affected during the Frasnian-Famennian faunal crisis.