First Occurrence

BACKGROUND: In longitudinal cohort studies, subjects may be lost to follow-up at any time during the study. This leads to attrition and thus to a risk of inaccurate and biased estimations. The purpose of this paper is to show how multiple imputation can take advantage of all the information collected during follow-up in order to estimate the cumulative probability P(E) of an event E, when the first occurrence of this event is observed at t successive time points of a longitudinal study with attrition.

METHODS: We compared the performance of multiple imputation with that of Kaplan-Meier estimation in several simulated attrition scenarios.

RESULTS: In missing-completely-at-random scenarios, the multiple imputation and Kaplan-Meier methods performed well in terms of bias (less than 1%) and coverage rate (range = [94.4%; 95.8%]). In missing-at-random scenarios, the Kaplan-Meier method was associated with a bias ranging from -5.1% to 7.0% and with a very poor coverage rate (as low as 0.2%). Multiple imputation performed much better in this situation (bias <2%, coverage rate >83.4%).

CONCLUSIONS: Multiple imputation shows promise for estimation of an occurrence rate in cohorts with attrition. This study is a first step towards defining appropriate use of multiple imputation in longitudinal studies.

Abstract: A new species of the sphenacodontid synapsid Dimetrodon, D. teutonis, is described on the basis of a single, adult specimen consisting of a large portion of the presacral vertebral column. The holotype was collected from the Lower Permian Tambach Formation, ...

The Cenomanian–Turonian boundary (CTB) section at Eastbourne, Sussex, England is the thickest at outcrop in the Anglo–Paris Basin, is rhythmic throughout, rich in macro-, micro- and nanno-fossils, and shows less diagenetic alteration than other sections in NW Europe. Geochemical and biostratigraphic data are all related to detailed (rhythmic) lithostratigraphy, allowing correlation with the global boundary stratotype section to within 20,000 years and accurate estimates of rates of changes. Very detailed stable isotope curves for oxygen and carbon are presented and show that the build-up phase of the CTB carbon excursion had two portions separated by a trough. Patterns of occurrence of coarse-fraction benthic foraminifera (>250 μm) show two peaks of extinction corresponding to the two build-up phases of the carbon excursion. Benthic and planktic foraminifera, ostracods and calcareous nannofossils all show declines in diversity and abundance across the CTB. Foraminifera also decline significantly in size. Key biomarker events for the CTB include: first occurrences of the ammonites Fagesia catinus and Mammites nodosoides, the bivalve Mytiloides, the planktic foraminifera Helvetoglobotruncana praehelvetica and Marginotruncana renzi, and the calcareous nannofossils Quadrum intermedium, Q. gartneri and Eprolithus octopetalus; and last occurrences of the ammonite Sciponoceras, the planktic foraminifera Rotalipora greenhornensis and R. cushmani, the calcareous nannofossils Corolithion kennedyi, Axopodorhabdus albianus, Lithraphidites acutus, Rhagodiscus asper and Microstaurus chiastius. Cyclostratigraphy allows very precise correlation of isotopic and bioevents with other sections in Europe and North America. Eastbourne is recommended as a NW European standard section.

... Secondary marker events around this boundary were suggested, such as the FO of the ammonite Placenticeras bidorsatum (Roemer, 1841), the FO of the nannofossil Broinsonia parca parca or the LO of the planktonic foraminifer Dicarinella asymetrica. ...

A high-resolution stratigraphy has been developed for the interval encompassing the Cenomanian-Turonian boundary (CTBI), by means of several lithological, biological and geochemical events. This work entails the study of two sections selected on the base of the completeness of their sedimentary record and their contrasting paleogeographical setting: (1) The Rock Canyon Anticline section west of Pueblo, Colorado, (US Western Interior

Bees are dependent on flower nectar and pollen (main sources of protein and energy, respectively) and have an important economic and ecological role as pollinators, representing about 40 to 90% of phanerogams pollinators in several ecosystems. This work presents a description of bee species from Parque Municipal da Cachoeirinha in Iporá, Goiás state, Brazil. A total of 58 hours of capturing were performed on November and December 2004 and on March and May 2005. A total of 933 individuals were collected, distributed in one family, 16 tribes, 33 genera, and 62 species. Meliponini tribe presented the highest number of individuals and species. Most abundant species were Trigona chanchamayoensis (16.51%), Tetragona clavipes (14.79%) and Apis mellifera and Trigona recursa (12.33%). This work presents the first occurrence in Goiás state for six genera and 12 species.

This study compared four treatments for bacterial endometritis in mares experimentally infected with Streptococcus zooepidemicus. Twenty-five mares were used, 20 resistant and five susceptible to endometritis. Mares would be in estrus when infected. Twenty-four hours after inoculation, clinical, bacteriological and cytological examinations were performed and repeated until the first occurrence: negative cytology and no Streptococcus growth or the seventh day post-infection. All mares showed clinical signs of endometritis and were assigned to one of the following treatments: (1) intrauterine infusion of fresh leukocytes; (2) intrauterine infusion of frozen-thawed leukocytes; (3) intrauterine infusion of lysed leukocytes; (4) intrauterine infusion of recombinant human interleukin-8 (rhIL-8); (5) control. Mares were submitted to all treatments, with at least a 14-day interval between treatments in a Latin square design. Treatment did not affect (P = 0.121) time needed for resistant mares to eliminate bacteria. Time needed for elimination of bacteria was similar in susceptible mares treated with fresh and frozen leukocytes (P = 0.333). Susceptible mares treated with frozen leukocytes also did not differ from those treated with lysed leukocytes (P = 0.227) for time to eliminate bacteria, but were significantly different (P > 0.02) from those treated with rhIL-8 and control. In resistant mares, physical clearance ability was probably the responsible for bacterial elimination. Intrauterine infusions in susceptible mares with viable or lysed leukocytes associated or not to opsonizing factors, reduced the time to elimination of bacteria. Infusions with bactericidal effect (functional neutrophils and granules) was likely effective and responsible for the more rapid elimination of bacteria in susceptible mares.

An integrated micropalaeontological (planktonic foraminifera and calcareous nannofossils), mineralogical and stable isotope investigation was carried out across the Cretaceous/Tertiary (K/T) boundary in a previously undescribed hemipelagic section (Forada section) cropping out in the Piave River Valley (Southern Alps, Belluno Province, NE Italy). Our results suggest that an apparently complete K/T transition with an expanded basal Danian is preserved in the Forada section. The K/T boundary is marked by a ca. 1.5-cm-thick clay interval intercalated in the pelagic carbonates of the Scaglia Rossa Formation. The boundary clay, characterised by an iridium anomaly, is constituted by a basal 1–2 mm-thick “green layer” and an overlying “red layer”. Below the boundary clay, the calcareous nannofossil Micula murus Zone and the planktonic foraminiferal Plummerita hankteninoides Zone, that characterise the terminal Maastrichtian in complete sections, have been identified. Virtually all the calcareous plankton biohorizons normally utilised in the early Danian have been recognised. Interestingly, the ranking of the various biohorizons is the same observed elsewhere if considering the single plankton groups separately, while several inconsistencies emerge if considering the relative succession of the two calcareous plankton groups simultaneously. We caution to infer hiatuses on a section based only on the spacing of the biohorizons of a single group because of the risk of diachroneities in the stressed early Danian environment. By comparing the “distance” of the key biohorizons (i.e. the First Occurrence (FO) of Cruciplacolithus primus and the Last Occurrence (LO) of Parvularugoglobigerina eugubina) from the boundary clay at Forada and in other complete classical sections, we have inferred that the early Danian is expanded in the Forada section. The section seems ideally suited for studying the recovery pattern of the pelagic ecosystem and calcareous plankton communities in the aftermath of the K/T catastrophe in a pelagic setting of the western central Tethys. The adaptive radiation of planktonic foraminifera was very rapid in contrast with the delayed diversification of coccolithophores. The latter show a ca. 21-cm-thick “dead zone” that is followed by a long-lasting survival interval (ca. 180-cm-thick, that might represent some 200 kyr) dominated by persistent Cretaceous coccolithophores and calcareous dinoflagellate Thoracosphaera spp. The temporal pattern in recovery of the coccolithophore and planktonic foraminiferal communities is decoupled as well pointing to their varying sensitivities to the K/T perturbation. It appears that the ecospace occupied by coccolithophores in the terminal Maastrichtian was occupied in the initial Danian by the calcareous dinoflagellates (Thoracosphaera spp.), that remained a significant component of the assemblage up to the base of the Prinsius dimorphosus Zone of Romein [Romein, A.J.T., 1979. Lineages in Early Paleogene calcareous nannoplankton. Utrecht Micropaleontological Bulletins, 22. 231 pp.], probably in the early Chron C29n. On the contrary, planktonic foraminifera seem to reach stable conditions earlier, in the late Cruciplacolithus primus Zone. The early Danian interval considered is also characterised by low Sr/Ca ratio of the biogenic carbonates that would suggest dramatically low coccolithophore productivity conditions, in agreement with previous flux studies. We speculate that the altered ecological structure of phytoplankton community and the low productivity of coccolithophores severely affected the efficiency of the transfer of organic carbon from the photic zone to the deep ocean, thus supporting the early Danian “living ocean” model of D'Hondt et al. [D'Hondt, S., Donaghay, P., Zachos, J.C., Luttenberg, D., Lindinger, M., 1998. Organic carbon fluxes and ecological recovery from the Cretaceous–Tertiary mass extinction. Science 282, 276–279].

... Ricardo Barragán a , Corresponding Author Contact Information , E-mail The Corresponding Author and Mihaela Carmen Melinte b. ... section studied in Mexico consists of marine carbonate facies of the upper part of the Cupido Formation (Imlay, 1937 and Humphrey, 1949) of ...

A high-resolution stratigraphy has been developed for the interval encompassing the Cenomanian–Turonian boundary (CTBI), by means of several lithological, biological and geochemical events. This work entails the study of two sections selected on the base of the completeness of their sedimentary record and their contrasting paleogeographical setting: (1) The Rock Canyon Anticline section west of Pueblo, Colorado, (US Western Interior

Two new species from Alaska and Washington, USA, Munida konara sp. nov., and Munida quadroblonga sp. nov., comprise the first occurrence of the Galatheinae (Galatheidae) in western North America and only the third confirmed fossil occurrence of the family and subfamily from the North Pacific Ocean. A new genus and species from Patagonia, Austromunida casadioi, documents the first occurrence of