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- Gamez Vintaned, Jose Antonio, et al.
(författare)
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Trace and soft body fossils from the Pedroche Formation (Ovetian, Lower Cambrian of the Sierra de Cordoba, S Spain) and their relation to the Pedroche event
- 2006
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Ingår i: Geobios. - : Elsevier BV. - 0016-6995. ; 39:4, s. 443-468
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Tidskriftsartikel (refereegranskat)abstract
- The low Lower Cambrian rocks from the Sierra de Cordoba contain one of the best successions in Europe, which consists of well exposed mixed facies with abundant fossil assemblages showing long stratigraphical ranges throughout the Pedroche Formation. These assemblages include diverse Ovetian archaeocyaths, trilobites, small shelly fossils, calcimicrobes, trace fossils and stromatolites. Trace fossils are still poorly known, and thus they are the main objective of this work. Ichnological data are obtained from the Arroyo de Pedroche 1, Arroyo de Pedroche 2 and Puente de Hierro sections. Trace fossils include the ichnogenera Bergaueria, aff. Bilinichnus, Cochlichnus, aff. Cosmorhaphe?, Cylindrichnus, Dactyloidites, Dimorphichnus, Diplichnites, Monocraterion, Palaeophycus, aff. Phycodes, Planolites, Psammichnites, Rusophycus, Skolithos, Torrowangea and Treptichnus, as well as faecal pellets, meniscate trace fossils and others. They are abundant in shales and sandstones, and indicate important changes in the benthic conditions with respect to the underlying Torrearboles Formation. Changes in fossil assemblages within Member I of the Pedroche Formation indicate palaeoccological disruptions, which led to the disappearance of numerous archaeocyath species and the decrease of stromatolite biodiversity. This was followed by dominance of trilobite and brachiopod assemblages, accompanied by trace fossils of the Psammichnites ichnosp. A ichnoassociation. This biotic turnover (Pedroche event) occurred at the lower part of the archaeocyath Zone III, within the Bigotina bivallata biozone. The diagnoses of the ichnospecies Cochlichnus anguineus and Dactyloidites cabanasi are emended. (c) 2006 Elsevier SAS. All rights reserved.
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| 3. |
- Linani, Eladio, et al.
(författare)
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New lower Ovetian trilobites (low lower Cambrian) from Sierra Morena (Spain)
- 2008
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Ingår i: Ameghiniana. - 0002-7014. ; 45:1, s. 123-138
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Tidskriftsartikel (refereegranskat)abstract
- Trilobites from two lower Ovetian (low lower Cambrian) localities in Sierra Morena (south of Spain) are described. Serrania palaciosi nov. sp. and Serrania? gordaensis nov. sp. come from the western locality (Alconera). New specimens of Serrania verae Linan Guijarro, 1978 come from the eastern locality (Sierra de Cordoba). The ontogenetic study of S. verae suggests that this species evolved from S. palaciosi. The new material allows us to include the genus Serrania within the new subfamily Serrinae defined herein, belonging to the family Bigotinidae. We include also two more genera with a lateral spine in the glabella, Hupetina and Sdzuyia. According to its stratigraphical position and the associated taxa, we can determinate that S. verae belongs to the Lemdadella linaresae Zone, corresponding to the lower part of the archaeocyatids Zone III. On the basis of stratigraphic and phylogenetic criteria, S. palaciosi nov. sp. and S.? gordaensis nov. sp. from Alconera belong probably to the Zone I of archaeocyathids. Some unclassifiable trilobite fragments have been also found in the Zone I of archaeocyathids at the Ovetian stratotype in Sierra de Cordoba, below the trilobite zone of Bigotina bivallata (which is equivalent to the trilobite Zone 0, or Eofallotaspis Zone, of Morocco). The new species defined herein are, up to now, the oldest trilobites described from Gondwana.
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| 4. |
- Wolk, David A., et al.
(författare)
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Use of flutemetamol F18-labeled positron emission tomography and other biomarkers to assess risk of clinical progression in patients with amnestic mild cognitive impairment
- 2018
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149. ; 75:9, s. 1114-1123
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Tidskriftsartikel (refereegranskat)abstract
- Importance: Patients with amnestic mild cognitive impairment (aMCI) may progress to clinical Alzheimer disease (AD), remain stable, or revert to normal. Earlier progression to AD among patients who were β-amyloid positive vs those who were β-amyloid negative has been previously observed. Current research now accepts that a combination of biomarkers could provide greater refinement in the assessment of risk for clinical progression. Objective: To evaluate the ability of flutemetamol F 18 and other biomarkers to assess the risk of progression from aMCI to probable AD. Design, Setting, and Participants: In this multicenter cohort study, from November 11, 2009, to January 16, 2014, patients with aMCI underwent positron emission tomography (PET) at baseline followed by local clinical assessments every 6 months for up to 3 years. Patients with aMCI (365 screened; 232 were eligible) were recruited from 28 clinical centers in Europe and the United States. Physicians remained strictly blinded to the results of PET, and the standard of truth was an independent clinical adjudication committee that confirmed or refuted local assessments. Flutemetamol F 18-labeled PET scans were read centrally as either negative or positive by 5 blinded readers with no knowledge of clinical status. Statistical analysis was conducted from February 19, 2014, to January 26, 2018. Interventions: Flutemetamol F 18-labeled PET at baseline followed by up to 6 clinical visits every 6 months, as well as magnetic resonance imaging and multiple cognitive measures. Main Outcomes and Measures: Time from PET to probable AD or last follow-upwas plotted as a Kaplan-Meier survival curve; PET scan results, age, hippocampal volume, and aMCI stage were entered into Cox proportional hazards logistic regression analyses to identify variables associated with progression to probable AD. Results: Of 232 patients with aMCI (118 women and 114 men; mean [SD] age, 71.1 [8.6] years), 98 (42.2%) had positive results detected on PET scan. By 36 months, the rates of progression to probable AD were 36.2% overall (81 of 224 patients), 53.6%(52 of 97) for patients with positive results detected on PET scan, and 22.8% (29 of 127) for patients with negative results detected on PET scan. Hazard ratios for association with progression were 2.51 (95% CI, 1.57-3.99; P < .001) for a positive β-amyloid scan alone (primary outcome measure), 5.60 (95%CI, 3.14-9.98; P < .001) with additional low hippocampal volume, and 8.45 (95%CI, 4.40-16.24; P < .001) when poorer cognitive status was added to the model. Conclusions and Relevance: A combination of positive results of flutemetamol F 18-labeled PET, low hippocampal volume, and cognitive status corresponded with a high probability of risk of progression from aMCI to probable AD within 36 months.
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