455 research outputs found
Modeling Long- and Short-Term Temporal Patterns with Deep Neural Networks
Multivariate time series forecasting is an important machine learning problem
across many domains, including predictions of solar plant energy output,
electricity consumption, and traffic jam situation. Temporal data arise in
these real-world applications often involves a mixture of long-term and
short-term patterns, for which traditional approaches such as Autoregressive
models and Gaussian Process may fail. In this paper, we proposed a novel deep
learning framework, namely Long- and Short-term Time-series network (LSTNet),
to address this open challenge. LSTNet uses the Convolution Neural Network
(CNN) and the Recurrent Neural Network (RNN) to extract short-term local
dependency patterns among variables and to discover long-term patterns for time
series trends. Furthermore, we leverage traditional autoregressive model to
tackle the scale insensitive problem of the neural network model. In our
evaluation on real-world data with complex mixtures of repetitive patterns,
LSTNet achieved significant performance improvements over that of several
state-of-the-art baseline methods. All the data and experiment codes are
available online.Comment: Accepted by SIGIR 201
Bioerosion and palaeoecological association of osteophagous insects in the Maastrichtian dinosaur Arenysaurus ardevoli
Bioerosions produced by the osteophagous diet of animals that fed on dinosaur bones are very scarce in the European fossil record. Herein we present bioerosion on hadrosaurid remains from the Maastrichtian Tremp Formation of the Pyrenean Basin, which is only the second such case recorded from the Iberian-Occitan Plate besides a sauropod from the Jurassic-Cretaceous of Valencia. The hadrosaurid fossil record is particularly rich in the Blasi sites of the Tremp Formation located in the municipality of Arén (Huesca, Spain). In this article, bones referred to the hadrosaurid Arenysaurus ardevoli from the Blasi-3 site are analysed to shed light on the palaeoenvironment and on the presence of a palaeoecological interaction between the hadrosaurid carcase and osteophagous tracemakers. Bioerosions recorded on the bones comprise tunnels, roundish holes, and straight notches, similar to the traces attributed to necrophagous insects (cf. Cuniculichnus seilacheri). Here, we record the first instance of the activity of these animals on dinosaur bones in the Upper Cretaceous of the Ibero-Occitan Plate. The results presented lead us to infer that the Arenysaurus bones were possibly transported by a storm or similar event to the Blasi-3 site, where they were exposed to post-mortem biotic interactions (eaten and partially decomposed by dermestid beetles) for a prolonged time period before they were completely buried. © 2021 The Authors. Lethaia published by John Wiley & Sons Ltd on behalf of Lethaia Foundatio
Slope Instability along the northeastern Iberian and Balearic continental margins
This paper gathers the available information on submarine landslides identified in the northeastern Iberian continental margin and presents new data on both already known landslides and new, previously unknown ones. The 2,000 km2, 26 km3 resulting deposit of the BIGâ95 debris flow in the Ebro margin; the 4 up to 16 km2, 0.4 km3 Eivissa slides in the Eivissa Channel; the 2 up to 65.6 km2, 1.46 km3 Barcelona slides in the shallow southern Catalan margin; and the western Gulf of Lions debris flow in the deep north Catalan margin are presented. This compilation is completed with several other previously undescribed small-scale mass-wasting deposits together with those observed in the Balearic Promontory. The amount and widespreading of submarine landslide deposits in the northern Iberian margins demonstrate that these margins are not an exception to the common occurence of these kind of structures worldwide, and gives an idea on this phenomena recurrence even in margins considered moderately quiet, in terms of seismicit
Neuregulin 3 Mediates Cortical Plate Invasion and Laminar Allocation of GABAergic Interneurons
Neural circuits in the cerebral cortex consist of excitatory pyramidal cells and inhibitory interneurons. These two main classes of cortical neurons follow largely different genetic programs, yet they assemble into highly specialized circuits during development following a very precise choreography. Previous studies have shown that signals produced by pyramidal cells influence the migration of cortical interneurons, but the molecular nature of these factors has remained elusive. Here, we identified Neuregulin 3 (Nrg3) as a chemoattractive factor expressed by developing pyramidal cells that guides the allocation of cortical interneurons in the developing cortical plate. Gain- and loss-of-function approaches reveal that Nrg3 modulates the migration of interneurons into the cortical plate in a process that is dependent on the tyrosine kinase receptor ErbB4. Perturbation of Nrg3 signaling in conditional mutants leads to abnormal lamination of cortical interneurons. Nrg3 is therefore a critical mediator in the assembly of cortical inhibitory circuits
A dynamic explanation for the origin of the western Mediterranean organic-rich layers
The eastern Mediterranean sapropels are among the most intensively investigated phenomena in the paleoceanographic record, but relatively little has been written regarding the origin of the equivalent of the sapropels in the western Mediterranean, the organic-rich layers (ORLs). ORLs are recognized as sediment layers containing enhanced total organic carbon that extend throughout the deep basins of the western Mediterranean and are associated with enhanced total barium concentration and a reduced diversity (dysoxic but not anoxic) benthic foraminiferal assemblage. Consequently, it has been suggested that ORLs represent periods of enhanced productivity coupled with reduced deep ventilation, presumably related to increased continental runoff, in close analogy to the sapropels. We demonstrate that despite their superficial similarity, the timing of the deposition of the most recent ORL in the Alboran Sea is different than that of the approximately coincident sapropel, indicating that there are important differences between their modes of formation. We go on to demonstrate, through physical arguments, that a likely explanation for the origin of the Alboran ORLs lies in the response of the western Mediterranean basin to a strong reduction in surface water density and a shoaling of the interface between intermediate and deep water during the deglacial period. Furthermore, we provide evidence that deep convection had already slowed by the time of Heinrich Event 1 and explore this event as a potential agent for preconditioning deep convection collapse. Important differences between Heinrich-like and deglacial-like influences are highlighted, giving new insights into the response of the western Mediterranean system to external forcing
Author correction : A small Cretaceous crocodyliform in a dinosaur nesting ground and the origin of sebecids
Correction to: Scientific Reports https://doi.org/10.1038/s41598-020-71975-y, published online 17 September 202
Isolation of Human Colon Stem Cells Using Surface Expression of PTK7
SummaryInsertion of reporter cassettes into the Lgr5 locus has enabled the characterization of mouse intestinal stem cells (ISCs). However, low cell surface abundance of LGR5 protein and lack of high-affinity anti-LGR5 antibodies represent a roadblock to efficiently isolate human colonic stem cells (hCoSCs). We set out to identify stem cell markers that would allow for purification of hCoSCs. In an unbiased approach, membrane-enriched protein fractions derived from in vitro human colonic organoids were analyzed by quantitative mass spectrometry. Protein tyrosine pseudokinase PTK7 specified a cell population within human colonic organoids characterized by highest self-renewal and re-seeding capacity. Antibodies recognizing the extracellular domain of PTK7 allowed us to isolate and expand hCoSCs directly from patient-derived mucosa samples. Human PTK7+ cells display features of canonical Lgr5+ ISCs and include a fraction of cells that undergo differentiation toward enteroendocrine lineage that resemble crypt label retaining cells (LRCs)
Holocene hydrography evolution in the Alboran Sea: a multi-record and multi-proxy comparison
A new high-resolution deglacial and Holocene sea surface temperature (SST)
reconstruction is presented for the Alboran Sea (western Mediterranean),
based on MgâCa ratios measured in the planktonic foraminifera Globigerina bulloides. This new
record is evaluated by comparison with other MgâCa SST records and
previously published alkenone SST reconstructions from the same region for
both the Holocene and glacial periods. In all cases there is a high degree
of coherence between the different MgâCa SST records but strong
discrepancies when compared to the alkenone SST records. We argue that
these discrepancies are due to differences in the proxy response during
deglaciation which we hypothesize to reflect a resilience strategy of G. bulloides,
changing its main growth season, and consequently MgâCa records a shorter
deglacial warming than alkenones. In contrast, short-term Holocene SST
variability is larger in the MgâCa SST than in the alkenone SST records.
We propose that the larger MgâCa SST variability is a result of spring
temperatures variability, while the smoothed alkenone SST variability
represents averaged annual temperatures. The MgâCa SST record
differentiates the Holocene into three periods: (1)Â the warmest SST values
occurred during the Early Holocene (11.7â9 cal. kyr BP), (2)Â a continuous
cooling trend occurred during the Middle Holocene that culminated in the
coldest Holocene SST having a double cold peak structure centred at around
4.2 cal. kyr BP, and (3)Â the Late Holocene (4.2 cal. kyr BP to present) did not follow any
clear cooling/warming trend although millennial-scale oscillations were
enhanced. This SST evolution is discussed in the context of the changing
properties in the Atlantic inflow water associated with North Atlantic
circulation conditions and also with local hydrographical and atmospheric
changes. We propose that a tight link between North Atlantic circulation
patterns and the inflow of surface waters into the Mediterranean played a
major role in controlling Holocene climatic variability of this region.</p
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