38 research outputs found
Neuron-glial Interactions
Although lagging behind classical computational neuroscience, theoretical and computational approaches are beginning to emerge to characterize different aspects of neuron-glial interactions. This chapter aims to provide essential knowledge on neuron-glial interactions in the mammalian brain, leveraging on computational studies that focus on structure (anatomy) and function (physiology) of such interactions in the healthy brain. Although our understanding of the need of neuron-glial interactions in the brain is still at its infancy, being mostly based on predictions that await for experimental validation, simple general modeling arguments borrowed from control theory are introduced to support the importance of including such interactions in traditional neuron-based modeling paradigms.Junior Leader Fellowship Program by âla Caixaâ Banking Foundation (LCF/BQ/LI18/11630006
Neuron-Glial Interactions
Although lagging behind classical computational neuroscience, theoretical and
computational approaches are beginning to emerge to characterize different
aspects of neuron-glial interactions. This chapter aims to provide essential
knowledge on neuron-glial interactions in the mammalian brain, leveraging on
computational studies that focus on structure (anatomy) and function
(physiology) of such interactions in the healthy brain. Although our
understanding of the need of neuron-glial interactions in the brain is still at
its infancy, being mostly based on predictions that await for experimental
validation, simple general modeling arguments borrowed from control theory are
introduced to support the importance of including such interactions in
traditional neuron-based modeling paradigms.Comment: 43 pages, 2 figures, 1 table. Accepted for publication in the
"Encyclopedia of Computational Neuroscience," D. Jaeger and R. Jung eds.,
Springer-Verlag New York, 2020 (2nd edition
Late Quaternary sea-level change and early human societies in the central and eastern Mediterranean Basin : an interdisciplinary review
This article reviews key data and debates focused on relative sea-level changes since the Last Interglacial (approximately the last 132,000 years) in the Mediterranean Basin, and their implications for past human populations. Geological and geomorphological landscape studies are critical to archaeology. Coastal regions provide a wide range of resources to the populations that inhabit them. Coastal landscapes are increasingly the focus of scholarly discussions from the earliest exploitation of littoral resources and early hominin cognition, to the inundation of the earliest permanently settled fishing villages and eventually, formative centres of urbanisation. In the Mediterranean, these would become hubs of maritime transportation that gave rise to the roots of modern seaborne trade. As such, this article represents an original review of both the geo-scientific and archaeological data that specifically relate to sea-level changes and resulting impacts on both physical and cultural landscapes from the Palaeolithic until the emergence of the Classical periods. Our review highlights that the interdisciplinary links between coastal archaeology, geomorphology and sea-level changes are important to explain environmental impacts on coastal human societies and human migration. We review geological indicators of sea level and outline how archaeological features are commonly used as proxies for measuring past sea levels, both gradual changes and catastrophic events. We argue that coastal archaeologists should, as a part of their analyses, incorporate important sea-level concepts, such as indicative meaning. The interpretation of the indicative meaning of Roman fishtanks, for example, plays a critical role in reconstructions of late Holocene Mediterranean sea levels. We identify avenues for future work, which include the consideration of glacial isostatic adjustment (GIA) in addition to coastal tectonics to explain vertical movements of coastlines, more research on Palaeolithic island colonisation, broadening of Palaeolithic studies to include materials from the entire coastal landscape and not just coastal resources, a focus on rescue of archaeological sites under threat by coastal change, and expansion of underwater archaeological explorations in combination with submarine geomorphology. This article presents a collaborative synthesis of data, some of which have been collected and analysed by the authors, as the MEDFLOOD (MEDiterranean sea-level change and projection for future FLOODing) community, and highlights key sites, data, concepts and ongoing debates
Prediction of successful voiding immediately after outpatient mid-urethral sling
We set out to identify predictors of successful voiding immediately after outpatient mid-urethral sling. The charts of 126 patients who underwent an outpatient mid-urethral sling procedure were identified. Using discharge without a urinary catheter as the dependent variable, logistic regression analysis modeled the relationship of independent variables including demographic, preoperative urodynamic, and perioperative variables. Sixty-one percent of the patients passed their immediate postoperative voiding trial. Logistic regression analysis revealed that parity \u3e or = 3, Valsalva leak point pressure \u3e 60 cm H(2)O, and high preoperative anxiety remained independently associated with successful voiding. Identifying preoperative variables that are associated with successful voiding after mid-urethral sling may be useful in helping to accurately shape patient expectations and identify those most likely to benefit from preoperative teaching of self-catheterization
Sea-level fluctuations during the last glacial cycle
The last glacial cycle was characterized by substantial millennial-scale climate fluctuations1, 2, 3, 4, 5, but the extent of any associated changes in global sea level (or, equivalently, ice volume) remains elusive. Highstands of sea level can be reconstructed from dated fossil coral reef terraces6, 7, and these data are complemented by a compilation of global sea-level estimates based on deep-sea oxygen isotope ratios at millennial-scale resolution8 or higher1. Records based on oxygen isotopes, however, contain uncertainties in the range of 30 m, or 1 °C in deep sea temperature9, 10. Here we analyse oxygen isotope records from Red Sea sediment cores to reconstruct the history of water residence times in the Red Sea. We then use a hydraulic model of the water exchange between the Red Sea and the world ocean to derive the sill depthâand hence global sea levelâover the past 470,000 years (470 kyr). Our reconstruction is accurate to within 12 m, and gives a centennial-scale resolution from 70 to 25 kyr before present. We find that sea-level changes of up to 35 m, at rates of up to 2 cm yr-1, occurred, coincident with abrupt changes in climate
Late Holocene pteropod distribution across the base of the south-eastern Mediterranean margin: the importance of the <i>></i> 63 ”m fraction
Euthecosomata pteropods were analysed in core sediments
collected
in the framework of the 2016 EUROFLEETS2 SEMSEEP cruise, offshore of Israel,
in the eastern Mediterranean Sea. The investigated cores were retrieved in a
deep-sea coral area at 690âm depth, an actively methane-seeping pockmark
area at 1038âm depth, and a deep-sea channel area at 1310âm water depth.
We
identified and documented the pteropod species belonging to the families
Heliconoididae, Limacinidae, Creseidae, Cavoliniidae, Cliidae, and Hyalocylidae
and to some heteropods. Our study highlights the importance of investigating
pteropods in the size fractions >â63â”m instead of
the
>â125â”m only. In particular, neglecting the small
size
fraction may result in a remarkable (up to 50â%â60â%) underestimation of the
relative abundance of the epipelagic species Creseis acicula and
Creseis conica and the mesopelagic
species Heliconoides inflatus. This may significantly affect
palaeoenvironmental reconstructions.
The observed presence of tropical species supports the suggestion that the
eastern Mediterranean is a refugium for these species. This study provides
a
basic benchmark for the late Holocene evolution of pteropod and heteropod distribution over 5800â5300âcalâBP across the base of the south-eastern Levantine margin.</p
MĂŒller glial cells contribute to dim light vision in the spectacled caiman ( Caiman crocodilus fuscus ): Analysis of retinal light transmission
Geochemical evidence for the link between sulfate reduction, sulfide oxidation and phosphate accumulation in a Late Cretaceous upwelling system
Background: On Late Cretaceous Tethyan upwelling sediments from the Mishash/Ghareb Formation (Negev, Israel),bulk geochemical and biomarker analyses were performed to explain the high proportion of phosphates in thelower part and of organic matter (OM) preserved in upper parts of the studied section. The profile is composed ofthree facies types; the underlying Phosphate Member (PM), the Oil Shale Member (OSM) and the overlying MarlMember (MM).
Results: Total organic carbon (TOC) contents are highly variable over the whole profile reaching from 0.6% in theMM, to 24.5% in the OSM. Total iron (TFe) varies from 0.1% in the PM to 3.3% in the OSM. Total sulfur (TS) rangesbetween 0.1% in the MM and 3.4% in the OSM, resulting in a high C/S ratio of 6.5 in the OSM section. A meanproportion of 11.5% total phosphorus (TP) in the PM changed abruptly with the facies to a mean value of only 0.9% in the OSM and the MM. The TOC/TOC ratios argue for a high bacterial sulfate reduction activity and in addition, results from fatty acidanalyses indicate that the activity of sulfide-oxidizing activity of bacteria was high during deposition of the PM,while decreasing during the deposition of the OSM.
Conclusions: The upwelling conditions effected a high primary productivity and consequently the presence of abundant OM. This, in combination with high sulfate availability in the sediments of the PM resulted in a higher sulfide production due to the activity of sulfate-reducing bacteria. Iron availability was a limiting factor during the deposition of the whole section, affecting the incorporation of S into OM. This resulted in the preservation of a substantial part of OM against microbial degradation due to naturally-occurring sulfurization processes expressed by the high C/S ratio of 6.5 in the OSM. Further, the abundant sulfide in the pore water supported the growth of sulfide-oxidizing bacteria promoting the deposition of P, which amounted to as much as 15% in the PM. These conditions changed drastically from the PM to the OSM, resulting in a significant reduction of the apatite precipitation and a high concentration of reactive S species reacting with the OM
Palaeoecology of enigmatic tube microfossils forming âcryptalgalâ fabrics (Late Quaternary, Red Sea)
Variability in the mountain environment at Melka Kunture archaeological site, Ethiopia, during the Early Pleistocene (~1.7 Ma) and the Mid-Pleistocene Transition (0.9â0.6 Ma)
In this paper, we present and discuss pollen data from the Early Pleistocene (1.8 to 1.6 Ma) â we use the revised timescale approved by IUGS, in which the base of the Pleistocene is defined by the GSSP of the Gelasian Stage at 2.588 (2.6) Ma (Gibbard et al. 2010) â and from the Mid-Pleistocene Transition (0.9 to 0.6 Ma) at Melka Kunture (Upper Awash, Ethiopia). At 2000 m asl in the Ethiopian highlands, these deposits yield many rich and successive archaeological sites, notably documenting the late Oldowan, the emergence of the Acheulean and the middle Acheulean. The stratigraphic position of the fifteen pollen samples is checked by 40Ar/39Ar dating and by geological investigation. Furthermore, they are now correlated to archaeological layers whose excavated lithic industries have been reinterpreted. Our study shows that mountain forest trees belonging to the present-day Afromontane complex were already established in Ethiopia at ~1.8 Ma and that the knappers of the Oldowan and early Acheulean could cope with mountain climatic conditions that had a large diurnal temperature range. Moreover, the new interpretation of pollen results emphasizes changes that occurred in the vegetation cover at 200- or 300-thousand-year snapshot intervals, one during the Early Pleistocene and another one later on, during the Mid-Pleistocene Transition. These changes concerned plant species and their respective abundance and appear to have been related to rainfall and temperature variability. The proportion of forest trees increased during wet episodes, whereas the influence of Afroalpine grassland indicators increased during cool and dry episodes. Variations in Early Pleistocene pollen data from Melka Kunture at ~1.8â1.6 Ma are consistent with isotopic evidence of precession variability as recorded at Olduvai and Turkana archaeological sites at ~2â1.8 Ma. For the Mid-Pleistocene Transition, variations in pollen data seem to match the climatic variability of isotopic and long pollen records from the Mediterranean region, notably upon the onset of dominant 100 ka-long glacial/interglacial cycles