9 research outputs found
Learning Transferable Spatiotemporal Representations from Natural Script Knowledge
Pre-training on large-scale video data has become a common recipe for
learning transferable spatiotemporal representations in recent years. Despite
some progress, existing methods are mostly limited to highly curated datasets
(e.g., K400) and exhibit unsatisfactory out-of-the-box representations. We
argue that it is due to the fact that they only capture pixel-level knowledge
rather than spatiotemporal commonsense, which is far away from cognition-level
video understanding. Inspired by the great success of image-text pre-training
(e.g., CLIP), we take the first step to exploit language semantics to boost
transferable spatiotemporal representation learning. We introduce a new pretext
task, Turning to Video for Transcript Sorting (TVTS), which sorts shuffled ASR
scripts by attending to learned video representations. We do not rely on
descriptive captions and learn purely from video, i.e., leveraging the natural
transcribed speech knowledge to provide noisy but useful semantics over time.
Furthermore, rather than the simple concept learning in vision-caption
contrast, we encourage cognition-level temporal commonsense reasoning via
narrative reorganization. The advantages enable our model to contextualize what
is happening like human beings and seamlessly apply to large-scale uncurated
video data in the real world. Note that our method differs from ones designed
for video-text alignment (e.g., Frozen) and multimodal representation learning
(e.g., Merlot). Our method demonstrates strong out-of-the-box spatiotemporal
representations on diverse video benchmarks, e.g., +13.6% gains over VideoMAE
on SSV2 via linear probing
Season-dependent heatwave mechanisms: A study of southern China
Heatwaves are among the deadliest weather-related disasters. They are not only seen in summer but also may appear in spring and autumn, especially under climate warming. Although the mechanisms of summertime heatwaves have been extensively studied, how they differ from spring and autumn seasons and possibly season-dependent mechanisms of heatwaves are poorly understood. Here we examine the specific processes associated with spring, summer, and autumn heatwaves in southern China during 1961–2020. We show that heatwaves in all three seasons are intensifying in frequency, duration, and intensity, and they exhibit distinctly season-dependent circulation changes. Summer heatwaves are characterized by a warm-core high-pressure structure, while spring and autumn heatwaves exhibit a warm low pattern. Summer heatwaves are mainly triggered by the westward (eastward) extension of the western North Pacific subtropical high (South Asian high), and are accompanied by anomalous lower-level anticyclone and positive pressure anomalies. In contrast, spring and autumn heatwaves coincide with lower-than-normal pressure and anomalous southwesterly over East Asia, indicative of a weakening of the East Asian winter monsoon circulation and the Siberian high. Their developments are linked to the eastward movement of an upper-tropospheric wave-like pattern over the mid-latitudes. It is also found that autumn heatwaves are largely contributed by local preceding soil moisture deficit, in comparison to spring and summer heatwaves. Our findings contribute to a better understanding of the heatwave characteristics in different seasons and provide insights into their mitigation strategies
Ether-Functionalized Ionic Liquids with Low Viscosity for Efficient SO<sub>2</sub> Capture
Three kinds of ionic liquids (ILs)
with ether-functionalized cations
and bisÂ(trifluoromethanesulfonyl)Âimide anions were synthesized in
our laboratory, and the SO<sub>2</sub> absorption capacities of those
three kinds of ILs were measured at temperature from 20 to 50 °C
and 1 bar. High capacity of SO<sub>2</sub>, excellent reversibility,
and high selectivity were achieved by the interaction between the
ILs and SO<sub>2</sub>. The absorption and desorption processes are
very fast, and SO<sub>2</sub> can be removed completely from the ILs.
Thermal stability was tested, and the decomposition temperatures of
the three kinds of ILs were all higher than 420 °C. NMR investigations
and computer simulation studies also show that SO<sub>2</sub> absorption
by these ILs is a physical process by forming weak hydrogen bonds
between the oxygen atoms in the SO<sub>2</sub> and the hydrogen atoms
in the ILs. This work further investigated how the water content affects
the solubility of SO<sub>2</sub> in the ILs. These ILs exhibit significant
improvements over traditional absorbents and indicate green, efficient,
and energy-saving methods for industry applications in SO<sub>2</sub> separation
Identification of key genes related to intramuscular fat deposition in Beijing-You chicken by mRNA and miRNA transcriptome analysis
ABSTRACT: Intramuscular fat (IMF) is an important factor affecting chicken quality. However, the age-related mechanism of IMF deposition has not yet been elucidated. In this study, the IMF, phospholipids (PL), triglycerides (TG), and fatty acid (FA) content in the breast muscle of Beijing-You chicken (BJY) at 1, 56, 98, and 120 d of age was measured, and mRNA and miRNA sequencing was integrated to explore the regulatory genes of IMF deposition. The results showed that the IMF content of BJY at 1 d of age was significantly higher than that at later stage of birth (P < 0.05). The transcriptome sequencing results showed that 7, 225 differentially expressed genes (DEGs) and 243 differentially expressed miRNAs (DE-miRNAs) were identified. The cluster analysis showed that the expression of DEGs and DE-miRNAs at 1 d of age was significantly different from that at later stages of birth. Furthermore, a potential mRNA-miRNA regulatory network related to IMF deposition was established by weighted gene co-expression network analysis (WGCNA); gga-miR-29c-3p-PIK3R1, gga-miR-6701-3p-PTEN, gga-miR-363-3p-PTEN, gga-miR-1563-WWP1, gga-miR-449c/d-5p-TRAF6, and gga-miR-6701-3p-BMPR1B were identified as key mRNA-miRNA pairs for the regulation of IMF deposition. These results will help elucidate the mechanism of IMF formation mediated by miRNAs in chickens, and provide a theoretical foundation for the genetic improvement of broiler meat quality
Appui aux travaux conduits sur les systèmes avec semis direct et couvert végétal en Haute Guinée et en Guinée forestière : mission réalisée du 30 juin au 13 juillet 2002
Prostate tumours are highly variable in their response to therapies, but clinically available prognostic factors can explain only a fraction of this heterogeneity. Here we analysed 200 whole-genome sequences and 277 additional whole-exome sequences from localized, non-indolent prostate tumours with similar clinical risk profiles, and carried out RNA and methylation analyses in a subset. These tumours had a paucity of clinically actionable single nucleotide variants, unlike those seen in metastatic disease. Rather, a significant proportion of tumours harboured recurrent non-coding aberrations, large-scale genomic rearrangements, and alterations in which an inversion repressed transcription within its boundaries. Local hypermutation events were frequent, and correlated with specific genomic profiles. Numerous molecular aberrations were prognostic for disease recurrence, including several DNA methylation events, and a signature comprised of these aberrations outperformed well-described prognostic biomarkers. We suggest that intensified treatment of genomically aggressive localized prostate cancer may improve cure rates