406 research outputs found
Arnmonoids and trilobites from the Vidrieros Formation (Horcada del Oro, Palentine Domain, NW Spain)
[Resumen] Se analizan los arnmonoideos y trilobites de una parte de la Fm. Vidrieros, detectándose por primera vez faunas de arnmnoideos característicos del dolll. Faunas de cefalópodos pertenecientes a los géneros Maeneceras, Pseudoclymenia, Protoxoclymenia? y Protomoceras se citan por primera vez en la Cordillera Cantábrica. Se registra novedosamente la presencia de Tornoceras en capas del doN del Dominio Palentino así como, el primer hallazgo en España de una forma de trilobite del género Dianops.[Abstract] Arnmonoids and Trilobites from a part of the Vidrieros Formation are analized,
detecting for the first time Arnmonoids forms characteristic of the doIl!. The f11'st reference about Cephalopod faunas belonging to the genera Maeneceras, Pseudoclymenia, Protoxoclymenia? y Protornoceras in the Cantabrian Mountains is given. The presence of Tomoceras is recorded for the first time in beds of dolV in the Palentine Domain, as well as the first finding in Spain of a Trilobite form belonging to the Dianops genus
Animal community dynamics at senescent and active vents at the 9° N East Pacific Rise after a volcanic eruption
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gollner, S., Govenar, B., Arbizu, P. M., Mullineaux, L. S., Mills, S., Le Bris, N., Weinbauer, M., Shank, T. M., & Bright, M. Animal community dynamics at senescent and active vents at the 9° N East Pacific Rise after a volcanic eruption. Frontiers in Marine Science, 6, (2020): 832, doi:10.3389/fmars.2019.00832.In 2005/2006, a major volcanic eruption buried faunal communities over a large area of the 9°N East Pacific Rise (EPR) vent field. In late 2006, we initiated colonization studies at several types of post eruption vent communities including those that either survived the eruption, re-established after the eruption, or arisen at new sites. Some of these vents were active whereas others appeared senescent. Although the spatial scale of non-paved (surviving) vent communities was small (several m2 compared to several km2 of total paved area), the remnant individuals at surviving active and senescent vent sites may be important for recolonization. A total of 46 meio- and macrofauna species were encountered at non-paved areas with 33 of those species detected were also present at new sites in 2006. The animals living at non-paved areas represent refuge populations that could act as source populations for new vent sites directly after disturbance. Remnants may be especially important for the meiofauna, where many taxa have limited or no larval dispersal. Meiofauna may reach new vent sites predominantly via migration from local refuge areas, where a reproductive and abundant meiofauna is thriving. These findings are important to consider in any potential future deep-sea mining scenario at deep-sea hydrothermal vents. Within our 4-year study period, we regularly observed vent habitats with tubeworm assemblages that became senescent and died, as vent fluid emissions locally stopped at patches within active vent sites. Senescent vents harbored a species rich mix of typical vent species as well as rare yet undescribed species. The senescent vents contributed significantly to diversity at the 9°N EPR with 55 macrofaunal species (11 singletons) and 74 meiofaunal species (19 singletons). Of these 129 species associated with senescent vents, 60 have not been reported from active vents. Tubeworms and other vent megafauna not only act as foundation species when alive but provide habitat also when dead, sustaining abundant and diverse small sized fauna.We received funding from the Austrian FWF (GrantP20190-B17; MB), the U.S. National Science Foundation (OCE-0424953; to LM, D. McGillicuddy, A. Thurnherr, J. Ledwell, and W. Lavelle; and OCE-1356738 to LM), and the European Union Seventh Framework Programme (FP7/2007-2013) under the MIDAS project, Grant Agreement No. 603418. Ifremer and CNRS (France) supported NL cruise participation and sensor developments. BG was supported by a postdoctoral fellowship from the Deep Ocean Exploration Institute at WHOI (United States). TS was supported by the U.S. National Science Foundation (OCE-0327261 to TS and OCE-0937395 to TS and BG)
Natural variability of geochemical conditions, biogeochemical processes and element fluxes in sediments of the CCZ
During RV SONNE cruise SO239 in March/April 2015 five sites in the area of the Clarion-Clipperton Fracture Zone (CCZ) in the eastern equatorial Pacific were visited as part of the JPI Oceans pilot action Ecological Aspects of Deep-Sea Mining“. Here, we present a comparable study on (1) the redox zonation in the sediments induced by the input flux of organic matter, (2) biogeochemical reactions including the driver of organic matter degradation and (3) diagenetic manganese redistribution and implications for manganese nodule formation
Human Cerebral Activation during Steady-State Visual-Evoked Responses
Flicker stimuli of variable frequency (2-90 Hz) elicit a steady-state
visual-evoked response (SSVER) in the electroencephalogram (EEG) with the same
frequency as the stimulus. In humans, the amplitude of this response peaks at
approximately 15 Hz, decreasing at higher stimulation frequencies. It was not
known whether this peak response corresponds to increased synaptic activity in
the visual cortex or to other mechanisms [for instance, the temporal coherence
(phase summation) of evoked responses]. We studied the SSVER in 16 normal
volunteers by means of visual stimulation at 14 different frequencies (from 5 to
60 Hz) while recording the EEG. In nine subjects of the group, we measured
regional cerebral blood flow (rCBF) with positron emission tomography
(PET)-H2(15)O at rest and during visual stimulation at five different
frequencies: 5, 10, 15, 25, and 40 Hz. We confirmed that the amplitude of the
SSVER in occipital regions peaks at 15 Hz stimulation. Applying to the PET rCBF
data a contrast weighted by the amplitude of the SSVER, we determined that the
primary visual cortex rCBF follows an activation pattern similar to the SSVER.
This finding suggests that the amplitude of the SSVER corresponds to increased
synaptic activity, specifically in Brodmann's area 17. Additionally, this study
showed that visual stimulation at 40 Hz causes selective activation of the
macular region of the visual cortex, and that a region in the dorsal aspect of
the Crus I lobule of the left cerebellar hemisphere is activated during
repetitive visual stimulation
11C-Methionine-Positron Emission Tomography as prognostic factor of recurrence in glioblastoma
Neuroimagen estructural y funcional en las enfermedades priónicas humanas
INTRODUCTION:
Prion diseases are neurodegenerative disorders resulting from the accumulation of a misfolded isoform of the cellular prion protein (PrPc). They can occur as acquired, sporadic or hereditary forms. Although prion diseases show a wide range of phenotypic variations, pathological features and clinical evolution, they are all characterised by a common unfavourable course and a fatal outcome.
REVIEW SUMMARY:
Some variants, such as kuru, have practically disappeared, while others, for example the variant Creutzfeldt-Jakob (vCJD) or those attributable to iatrogenic causes, are still in force and pose a challenge to current medicine. There are no definitive pre-mortem diagnostic tests, except for vCJD, where a tonsil biopsy detects 100% of the cases. For this reason, diagnostic criteria dependent on statistical probability have had to be created. These require complementary examinations, such as an electroencephalogram (EEG) or the detection of 14-3-3 protein in cerebrospinal fluid (CSF). Only the "pulvinar sign" in magnetic resonance imaging (MRI) has been included as a vCJD diagnostic criterion. The present review discusses neuroimaging findings for each type of prion disease in patients with a definitive histopathological diagnosis.
CONCLUSIONS:
The aim is to define the usefulness of these complementary examinations as a tool for the diagnosis of this family of neurodegenerative diseases
Evolutionary-based prediction interval estimation by blending solar radiation forecasting models using meteorological weather types
Recent research has shown that the integration or blending of different forecasting models is able to improve the predictions of solar radiation. However, most works perform model blending to improve point forecasts, but the integration of forecasting models to improve probabilistic forecasting has not received much attention. In this work the estimation of prediction intervals for the integration of four Global Horizontal Irradiance (GHI) forecasting models (Smart Persistence, WRF-solar, CIADcast, and Satellite) is addressed. Several short-term forecasting horizons, up to one hour ahead, have been analyzed. Within this context, one of the aims of the article is to study whether knowledge about the synoptic weather conditions, which are related to the stability of weather, might help to reduce the uncertainty represented by prediction intervals. In order to deal with this issue, information about which weather type is present at the time of prediction, has been used by the blending model. Four weather types have been considered. A multi-objective variant of the Lower Upper Bound Estimation approach has been used in this work for prediction interval estimation and compared with two baseline methods: Quantile Regression (QR) and Gradient Boosting (GBR). An exhaustive experimental validation has been carried out, using data registered at Seville in the Southern Iberian Peninsula. Results show that, in general, using weather type information reduces uncertainty of prediction intervals, according to all performance metrics used. More specifically, and with respect to one of the metrics (the ratio between interval coverage and width), for high-coverage (0.90, 0.95) prediction intervals, using weather type enhances the ratio of the multi-objective approach by 2%¿. Also, comparing the multi-objective approach versus the two baselines for high-coverage intervals, the improvement is 11%¿% over QR and 10%¿% over GBR. Improvements for low-coverage intervals (0.85) are smaller.The authors are supported by projects funded by Agencia Estatal de Investigación, Spain (PID2019-107455RB-C21 and PID2019-107455RB-C22/AEI/10.13039/501100011033). Also supported by Spanish Ministry of Economy and Competitiveness, project ENE2014-56126-C2-1-R and ENE2014-56126-C2-2-R (http://prosol.uc3m.es). The University of Jaén team is also supported by FEDER, Spain funds and by the Junta de Andalucía, Spain (Research group TEP-220
Tomografía de emisión de fotones cerebral. Valor del índice corticocerebeloso y patrones gammagráficos en la enfermedad de Alzheimer y otras afecciones
Brain single photon emission computed tomography (SPECT) with 99mTc-HMPAO is a diagnostic tool for evaluating regional cerebral blood flow. Recently, the diagnostic possibilities of the method are being investigated in some neurologic disorders, such as cerebrovascular accidents, seizures and dementia. This work has been carried out with 54 subjects, 9 healthy volunteers and 45 patients (31 dementia and 14 epileptics), in order to evaluate gammagraphic patterns and the utility of cortico/cerebellar activity indexes. An interesting diagnostic finding is a significant decrease (p less than 0.001) in perfusion of temporoparietal regions in the patients with Alzheimer's disease in relation with the healthy volunteers' group. We have not found significant changes in perfusion in the group of epileptic patients during the interictal phase. We conclude emphasizing the interest of the SPECT in the differential diagnosis of dementia
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