Obstetrical Management of Cases of Urinary Infections in Pregnancy

Newell, Franklin S.

doi:10.1056/nejm193002202020803

Cited by 3 publications

(3 citation statements)

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“…Similar mechanisms that are related directly to sea-level variation and the common-cause hypothesis have been proposed for changes in biodiversity and several of the major extinctions (37)(38)(39)(40)(41)(42). However, such explanations generally have been limited to specific time intervals and have been discounted in favor of unusual and abrupt forcing mechanisms, such as asteroid impacts (14,43), large volcanic eruptions (44,45), and other rapid or unusual environmental changes (45,46).…”

Section: Discussionmentioning

confidence: 65%

“…However, such explanations generally have been limited to specific time intervals and have been discounted in favor of unusual and abrupt forcing mechanisms, such as asteroid impacts (14,43), large volcanic eruptions (44,45), and other rapid or unusual environmental changes (45,46). Nevertheless, because the geologic record is able to predict such a large component of the variability in the marine animal fossil record and because the mass extinctions do not appear to be prominent outliers, it would seem prudent to revisit some of the classic unifying hypotheses that are grounded in the effects of continually operating processes (37) and to reevaluate seriously the extent to which unusual or episodic events are required to explain the macroevolutionary history of marine animals.…”

Section: Discussionmentioning

confidence: 99%

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Geologic constraints on the macroevolutionary history of marine animals

Peters

2005

Proc. Natl. Acad. Sci. U.S.A.

262

279

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The causes of mass extinctions and the nature of taxonomic radiations are central questions in paleobiology. Several episodes of taxonomic turnover in the fossil record, particularly the major mass extinctions, are generally thought to transcend known biases in the geologic record and are widely interpreted as distinct macroevolutionary phenomena that require unique forcing mechanisms. Here, by using a previously undescribed compilation of the durations of sedimentary rock sequences, I compare the rates of expansion and truncation of preserved marine sedimentary basins to rates of origination and extinction among Phanerozoic marine animal genera. Many features of the highly variable record of taxonomic first and last occurrences in the marine animal fossil record, including the major mass extinctions, the frequency distribution of genus longevities, and short-and long-term patterns of genus diversity, can be predicted on the basis of the temporal continuity and quantity of preserved sedimentary rock. Although these results suggest that geologically mediated sampling biases have distorted macroevolutionary patterns in the fossil record, preservation biases alone cannot easily explain the extent to which the sedimentary record duplicates paleobiological patterns. Instead, these results suggest that the processes responsible for producing variability in the sedimentary rock record, such as plate tectonics and sea-level change, may have been dominant and consistent macroevolutionary forces throughout the Phanerozoic.biodiversity ͉ mass extinction ͉ paleobiology ͉ sedimentary rock ͉ sequence stratigraphy O ne of the most striking aspects of the marine animal fossil record is that it preserves a volatile history of biodiversity and rates of taxonomic origination and extinction. Understanding the causes and evolutionary consequences of this volatility is one of the central goals of paleobiology. It has long been recognized, however, that the quantity of preserved sedimentary rock varies over short and long intervals of geologic time (1-3) and that this variation is correlated with several important macroevolutionary patterns in the fossil record, including changes in biodiversity (4-8) and rates of taxonomic extinction (4, 9, 10). The mutual correlations between preserved rock quantity and macroevolutionary patterns have been interpreted as evidence for either preservation biases that distort the apparent timings of extinction and origination in the fossil record (bias hypothesis) (4-7, 10) or a common pattern that is induced by processes, such as sea level fluctuations, plate tectonics, and resultant changes in marine shelf area, that affect both the amount of preserved rock and biological evolution (commoncause hypothesis) (6, 7, 9-12). Nevertheless, some workers have proffered that many intervals of turnover in the fossil record, particularly the major mass extinctions (13), are too substantial to be the result of preservation biases and are sufficiently distinct to require unique forcing mechanisms (14-17).Evaluati...

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Section: Discussionmentioning

confidence: 65%

Section: Discussionmentioning

confidence: 99%

Geologic constraints on the macroevolutionary history of marine animals

Peters

2005

Proc. Natl. Acad. Sci. U.S.A.

262

279

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“…Interest among paleontologists in the tempo of speciation and extinction can be traced to Simpson (1) and Newell (2), who both voiced the opinion that much of the evolutionary record reflects deterministic responses of biotas to the physical and biotic environment. Patterns of appearance and extinction were related by these pioneers to intertaxon competition, paleogeographic change, and environmental change.…”

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confidence: 99%

Repeatability of taxon longevity in successive foraminifera radiations and a theory of random appearance and extinction

Levinton¹,

Ginzburg²

1984

Proc. Natl. Acad. Sci. U.S.A.

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An analysis of taxonomic longevity for species of the two Cenozoic radiations of Caribbean planktonic foraminifera shows strong similarity in longevity for extinct taxa, though extant species of the latter radiation are biased towards longer-lived forums. In this case, the present is not the key to the past. A simple one-parametric stochastic model predicts generally the shape of the distributions, though there is an excess of species with model longevity and a deficiency of longer-lived forms, relative to the prediction of the model. Although the one parameter may relate to the biology of the group under consideration, the distribution about the mode may reflect random appearance-extinction processes.Interest among paleontologists in the tempo of speciation and extinction can be traced to Simpson (1) and Newell (2), who both voiced the opinion that much of the evolutionary record reflects deterministic responses of biotas to the physical and biotic environment. Patterns of appearance and extinction were related by these pioneers to intertaxon competition, paleogeographic change, and environmental change.More recently, many have revived the argument; some have introduced more deterministic parameters, such as sea-floor spreading and continental drift (3), and interspecific interactions (4), while others have claimed that the overall pattern of appearance and extinction follows essentially a stochastic process (5). This argument parallels the controversy in island biogeography over interactions among species on islands that might regulate species diversity (6).Raup and colleagues (7) simulated speciation and extinction and claimed that computer-geqerated clades could not be distinguished easily from data obtained from the fossil record. In particular, the average time of maximal taxon richness was midway between the first and last appearance of the clade in both simulations and fossil data. Although Flessa and Levinton (8) To obtain the longevity spectrum, we used a corrective equation (Fig. 1) that related a length of ranges on a stratigraphic range chart to independent radiometric dates presented by Saunders et al. (11). We used an exponential fit, but any of a number of other fits do not substantially alter our results. Longevity reckoned by number of foraminiferal zones is not as useful, because zone longevity increases by a factor of 2 in the Oligocene, decreases to approximate Paleocene-Eocene levels [ca. 1-1.5 million years (my)] in the Miocene, and then decreases dramatically towards the present. With this data set, we cannot correct for pseudoextinction, the transition of one taxonomic form to another, due to phyletic evolution. This effect tends to decrease taxon longevity by confounding it with morphological evolution. In the case in which pseudoextinction dominates, our estimate of longevity is simply a measure of the lifespan of a given morphotype.Using the calibration, Fig. 2 shows the distribution of longevities for the Paleogene (N -128) and Neogene (N = 59) radiations. They point to a r...

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Vesicoureteral reflux as an etiologic factor in pyelitis of pregnancy

Morris

Brunton

1933

American Journal of Obstetrics and Gynecology

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Obstetrical Management of Cases of Urinary Infections in Pregnancy

Cited by 3 publications

References 0 publications

Geologic constraints on the macroevolutionary history of marine animals

Geologic constraints on the macroevolutionary history of marine animals

Repeatability of taxon longevity in successive foraminifera radiations and a theory of random appearance and extinction

Vesicoureteral reflux as an etiologic factor in pyelitis of pregnancy

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