Importance of ocean mesoscale variability for air-sea interactions in the Gulf of Mexico

Mesoscale variability of currents in the Gulf of Mexico (GoM) can affect oceanic heat advection and air-sea heat exchanges, which can influence climate extremes over North America. This study is aimed at understanding the influence of the oceanic mesoscale variability on the lower atmosphere and air-sea heat exchanges. The study contrasts global climate model (GCM) with 0.1° ocean resolution (high resolution; HR) with its low-resolution counterpart (1° ocean resolution with the same 0.5° atmosphere resolution; LR). The LR simulation is relevant to current generation of GCMs that are still unable to resolve the oceanic mesoscale. Similar to observations, HR exhibits positive correlation between sea surface temperature (SST) and surface turbulent heat flux anomalies, while LR has negative correlation. For HR, we decompose lateral advective heat fluxes in the upper ocean into mean (slowly varying) and mesoscale-eddy (fast fluctuations) components. We find that the eddy flux divergence/convergence dominates the lateral advection and correlates well with the SST anomalies and air-sea latent heat exchanges. This result suggests that oceanic mesoscale advection supports warm SST anomalies that in turn feed surface heat flux. We identify anticyclonic warm-core circulation patterns (associated Loop Current and rings) which have an average diameter of ~350 km. These warm anomalies are sustained by eddy heat flux convergence at submonthly time scales and have an identifiable imprint on surface turbulent heat flux, atmospheric circulation, and convective precipitation in the northwest portion of an averaged anticyclone. ©2017. American Geophysical Union

Calcium Signaling T-type Calcium Channels Involved In Collagen Fragment-Induced Smooth Muscle Cell Death

International audienceApoptosis of smooth muscle cells (SMC) due to changes in extracellular matrix has emerged as an important factor underlying vascular and visceral disease progression. The calcium signal induced by extracellular matrix fragmentation also plays a pivotal role in cell death and disease evolution. Here, we found that KDGEA, a particular motif of type I collagen, induced rat duodenal SMC death in cultures through specific interaction with α 2 β 1 integrin signaling as suggested by (1) the absence of KDGAA effect, an inactive analog of KDGEA, or LDV, a fibronectin fragment that recognizes α 4 β 1 integrin, and (2) the inhibition of SMC death induced by KDGEA when α 2 β 1 expression was knocked down by antisense oligonucleotide. DNA fragmentation was also detected in KDGEA-treated cells, thus suggesting activation of an apoptotic process. These KDGEA-activated processes were totally blunted by pharmacological modulation of Ca 2+ entry through T-type Ca 2+ channels and antisense oligonucleotides directed against these channels. KDGEA also increased caffeine-induced calcium release and this effect was abolished when cultures were treated with either antisense oligonucleotide or T-type channel blockers. These results suggested that type I collagen peptide KDGEA can induce the death of SMC through T-type Ca 2+ channel activation and alteration of calcium release from sarcoplasmic reticulum

Self-supervised video pretraining yields human-aligned visual representations

Humans learn powerful representations of objects and scenes by observing how they evolve over time. Yet, outside of specific tasks that require explicit temporal understanding, static image pretraining remains the dominant paradigm for learning visual foundation models. We question this mismatch, and ask whether video pretraining can yield visual representations that bear the hallmarks of human perception: generalisation across tasks, robustness to perturbations, and consistency with human judgements. To that end we propose a novel procedure for curating videos, and develop a contrastive framework which learns from the complex transformations therein. This simple paradigm for distilling knowledge from videos, called VITO, yields general representations that far outperform prior video pretraining methods on image understanding tasks, and image pretraining methods on video understanding tasks. Moreover, VITO representations are significantly more robust to natural and synthetic deformations than image-, video-, and adversarially-trained ones. Finally, VITO's predictions are strongly aligned with human judgements, surpassing models that were specifically trained for that purpose. Together, these results suggest that video pretraining could be a simple way of learning unified, robust, and human-aligned representations of the visual world.Comment: Technical repor

Sequencing of 6.7 Mb of the melon genome using a BAC pooling strategy

<p>Abstract</p> <p>Background</p> <p><it>Cucumis melo </it>(melon) belongs to the Cucurbitaceae family, whose economic importance among horticulture crops is second only to Solanaceae. Melon has a high intra-specific genetic variation, morphologic diversity and a small genome size (454 Mb), which make it suitable for a great variety of molecular and genetic studies. A number of genetic and genomic resources have already been developed, such as several genetic maps, BAC genomic libraries, a BAC-based physical map and EST collections. Sequence information would be invaluable to complete the picture of the melon genomic landscape, furthering our understanding of this species' evolution from its relatives and providing an important genetic tool. However, to this day there is little sequence data available, only a few melon genes and genomic regions are deposited in public databases. The development of massively parallel sequencing methods allows envisaging new strategies to obtain long fragments of genomic sequence at higher speed and lower cost than previous Sanger-based methods.</p> <p>Results</p> <p>In order to gain insight into the structure of a significant portion of the melon genome we set out to perform massive sequencing of pools of BAC clones. For this, a set of 57 BAC clones from a double haploid line was sequenced in two pools with the 454 system using both shotgun and paired-end approaches. The final assembly consists of an estimated 95% of the actual size of the melon BAC clones, with most likely complete sequences for 50 of the BACs, and a total sequence coverage of 39x. The accuracy of the assembly was assessed by comparing the previously available Sanger sequence of one of the BACs against its 454 sequence, and the polymorphisms found involved only 1.7 differences every 10,000 bp that were localized in 15 homopolymeric regions and two dinucleotide tandem repeats. Overall, the study provides approximately 6.7 Mb or 1.5% of the melon genome. The analysis of this new data has allowed us to gain further insight into characteristics of the melon genome such as gene density, average protein length, or microsatellite and transposon content. The annotation of the BAC sequences revealed a high degree of collinearity and protein sequence identity between melon and its close relative <it>Cucumis sativus </it>(cucumber). Transposon content analysis of the syntenic regions suggests that transposition activity after the split of both cucurbit species has been low in cucumber but very high in melon.</p> <p>Conclusions</p> <p>The results presented here show that the strategy followed, which combines shotgun and BAC-end sequencing together with anchored marker information, is an excellent method for sequencing specific genomic regions, especially from relatively compact genomes such as that of melon. However, in agreement with other results, this map-based, BAC approach is confirmed to be an expensive way of sequencing a whole plant genome. Our results also provide a partial description of the melon genome's structure. Namely, our analysis shows that the melon genome is highly collinear with the smaller one of cucumber, the size difference being mainly due to the expansion of intergenic regions and proliferation of transposable elements.</p

Influence of frontal cyclone evolution on the 2009 (Ekman) and 2010 (Franklin) Loop Current eddy detachment events

The anticyclonic Loop Current Eddy (LCE) shedding events are strongly associated with the evolution of Loop Current Frontal Eddies (LCFEs) over the eastern Gulf of Mexico (GoM). A numerical simulation, in tandem with in situ measurements and satellite data, was used to investigate the Loop Current (LC) evolution and the surrounding LCFE formation, structure, growth and migration during the Eddy Ekman and Eddy Franklin shedding events in the summers of 2009 and 2010, respectively. During both events, northern GoM LCFEs appeared vertically coherent to at least 1500 m in temperature observations. They propagated towards the base of the LC, where, together with the migration of Campeche Bank (southwest GoM shelf) eddies from south of the LC, contributed to its "necking-down". Growth of Campeche Bank LCFEs involved in Eddy Franklin was partially attributed to Campeche Bank waters following upwelling events. Slope processes associated with such upwelling included offshore exports of high positive potential vorticity that may trigger cyclone formation and growth. The advection and growth of LCFEs, originating from the northern and southern GoM, and their interaction with the LC over the LCE detachment area favor shedding conditions and may contribute to the final separation of the LCE

Retrotransposons are specified as DNA replication origins in the gene-poor regions of Arabidopsis heterochromatin

Genomic stability depends on faithful genome replication. This is achieved by the concerted activity of thousands of DNA replication origins (ORIs) scattered throughout the genome. The DNA and chromatin features determining ORI specification are not presently known. We have generated a high-resolution genome-wide map of 3230 ORIs in cultured Arabidopsis thaliana cells. Here, we focused on defining the features associated with ORIs in heterochromatin. In pericentromeric gene-poor domains ORIs associate almost exclusively with the retrotransposon class of transposable elements (TEs), in particular of the Gypsy family. ORI activity in retrotransposons occurs independently of TE expression and while maintaining high levels of H3K9me2 and H3K27me1, typical marks of repressed heterochromatin. ORI-TEs largely colocalize with chromatin signatures defining GC-rich heterochromatin. Importantly, TEs with active ORIs contain a local GC content higher than the TEs lacking them. Our results lead us to conclude that ORI colocalization with retrotransposons is determined by their transposition mechanism based on transcription, and a specific chromatin landscape. Our detailed analysis of ORIs responsible for heterochromatin replication has implications on the mechanisms of ORI specification in other multicellular organisms in which retrotransposons are major components of heterochromatin and of the entire genome

Highly variable upper and abyssal overturning cells in the South Atlantic

The Meridional Overturning Circulation (MOC) is a primary mechanism driving oceanic heat redistribution on Earth, thereby affecting Earth’s climate and weather. However, the full-depth structure and variability of the MOC are still poorly understood, particularly in the South Atlantic. This study presents unique multiyear records of the oceanic volume transport of both the upper (~3100 meters) overturning cells based on daily moored measurements in the South Atlantic at 34.5°S. The vertical structure of the time-mean flows is consistent with the limited historical observations. Both the upper and abyssal cells exhibit a high degree of variability relative to the temporal means at time scales, ranging from a few days to a few weeks. Observed variations in the abyssal flow appear to be largely independent of the flow in the overlying upper cell. No meaningful trends are detected in either cell.Fil: Kersalé, Marion. National Ocean And Atmospheric Administration; Estados Unidos. University of Miami; Estados UnidosFil: Meinen, Christopher S.. National Ocean And Atmospheric Administration; Estados UnidosFil: Perez, Renellys C.. National Ocean And Atmospheric Administration; Estados UnidosFil: Le Hénaff, Matthieu. National Ocean And Atmospheric Administration; Estados Unidos. University of Miami; Estados UnidosFil: Valla, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval. Departamento Oceanografía; ArgentinaFil: Lamont, Tarron. University of Cape Town; SudáfricaFil: Sato, Olga T.. Universidade de Sao Paulo; BrasilFil: Dong, Shenfu. National Ocean And Atmospheric Administration; Estados UnidosFil: Terre, T.. University of Brest; Francia. Centre National de la Recherche Scientifique; FranciaFil: van Caspel, M.. Universidade de Sao Paulo; BrasilFil: Chidichimo, María Paz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval. Departamento Oceanografía; ArgentinaFil: van den Berg, Marcel Alexander. Department of Environmental Affairs; SudáfricaFil: Speich, Sabrina. University Of Cape Town; SudáfricaFil: Piola, Alberto Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ecole Normale Superieure. Laboratoire de Meteorologie Dynamique; Francia. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval. Departamento Oceanografía; Argentina. Instituto Franco-Argentino sobre Estudios del Clima y sus Impactos; Argentina. Universidad de Buenos Aires; ArgentinaFil: Campos, Edmo. Universidade de Sao Paulo; Brasil. American University Of Sharjah.; Emiratos Árabes UnidosFil: Ansorge, Isabelle. University of Cape Town; SudáfricaFil: Volkov, Denis L.. University of Miami; Estados Unidos. National Ocean And Atmospheric Administration; Estados UnidosFil: Lumpkin, Rick. National Ocean And Atmospheric Administration; Estados UnidosFil: Garzoli, S. L.. University of Miami; Estados Unidos. National Ocean And Atmospheric Administration; Estados Unido

The meta-crisis of secular capitalism

The current global economic crisis concerns the way in which contemporary capitalism has turned to financialisation as a double cure for both a falling rate of profit and a deficiency of demand. Although this turning is by no means unprecedented, policies of financialisation have depressed demand (in part as a result of the long-term stagnation of average wages) while at the same time not proving adequate to restore profits and growth. This paper argues that the current crisis is less the ‘normal’ one that has to do with a constitutive need to balance growth of abstract wealth with demand for concrete commodities. Rather, it marks a meta-crisis of capitalism that is to do with the difficulties of sustaining abstract growth as such. This meta-crisis is the tendency at once to abstract from the real economy of productive activities and to reduce everything to its bare materiality. By contrast with a market economy that binds material value to symbolic meaning, a capitalist economy tends to separate matter from symbol and reduce materiality to calculable numbers representing ‘wealth’. Such a conception of wealth rests on the aggregation of abstract numbers that cuts out all the relational goods and the ‘commons’ on which shared prosperity depends

Ocean observations in support of studies and forecasts of tropical and extratropical cyclones

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Domingues, R., Kuwano-Yoshida, A., Chardon-Maldonado, P., Todd, R. E., Halliwell, G., Kim, H., Lin, I., Sato, K., Narazaki, T., Shay, L. K., Miles, T., Glenn, S., Zhang, J. A., Jayne, S. R., Centurioni, L., Le Henaff, M., Foltz, G. R., Bringas, F., Ali, M. M., DiMarco, S. F., Hosoda, S., Fukuoka, T., LaCour, B., Mehra, A., Sanabia, E. R., Gyakum, J. R., Dong, J., Knaff, J. A., & Goni, G. Ocean observations in support of studies and forecasts of tropical and extratropical cyclones. Frontiers in Marine Science, 6, (2019): 446, doi:10.3389/fmars.2019.00446.Over the past decade, measurements from the climate-oriented ocean observing system have been key to advancing the understanding of extreme weather events that originate and intensify over the ocean, such as tropical cyclones (TCs) and extratropical bomb cyclones (ECs). In order to foster further advancements to predict and better understand these extreme weather events, a need for a dedicated observing system component specifically to support studies and forecasts of TCs and ECs has been identified, but such a system has not yet been implemented. New technologies, pilot networks, targeted deployments of instruments, and state-of-the art coupled numerical models have enabled advances in research and forecast capabilities and illustrate a potential framework for future development. Here, applications and key results made possible by the different ocean observing efforts in support of studies and forecasts of TCs and ECs, as well as recent advances in observing technologies and strategies are reviewed. Then a vision and specific recommendations for the next decade are discussed.This study was supported by the National Oceanic and Atmospheric Administration and JSPS KAKENHI (Grant Numbers: JP17K19093, JP16K12591, and JP16H01846)