1,544 research outputs found
Fracture Energy of High-Strength Concrete
The effects of water-cementitious materials ratio, age, and aggregate type on the compressive strength, flexural strength, and fracture energy of concretes with compressive strengths ranging from 20 to 99 MPa (2900 to 14,400 psi) are studied. Concrete mixtures contain either basalt or crushed limestone aggregate with maximum sizes of 12 or 19 mm (1/2 or 3/4 in.). Mixtures are tested at ages ranging from 5 to 180 days and have water-cementitious (w/cm) ratios ranging from 0.24 to 0.50. High-strength concrete containing the higher-strength, basalt coarse aggregate attains higher compressive and flexural strengths than high-strength concrete containing limestone. The compressive and flexural strengths of medium and normal strength
concretes (fc¢ up to approximately 60 MPa [9000 psi]) are affected little by aggregate type. Concrete containing basalt yields significantly higher fracture energy than concrete containing limestone, with fracture energy governed principally by aggregate properties, independent of compressive strength, w/cm ratio, and age. Overall, as compressive strength increases, the energy stored in the material at the peak tensile load increases while the ability of the material to dissipate energy remains approximately constant. The result is increasingly brittle behavior as compressive strength increases
Towards Generic Image Manipulation Detection with Weakly-Supervised Self-Consistency Learning
As advanced image manipulation techniques emerge, detecting the manipulation
becomes increasingly important. Despite the success of recent learning-based
approaches for image manipulation detection, they typically require expensive
pixel-level annotations to train, while exhibiting degraded performance when
testing on images that are differently manipulated compared with training
images. To address these limitations, we propose weakly-supervised image
manipulation detection, such that only binary image-level labels (authentic or
tampered with) are required for training purpose. Such a weakly-supervised
setting can leverage more training images and has the potential to adapt
quickly to new manipulation techniques. To improve the generalization ability,
we propose weakly-supervised self-consistency learning (WSCL) to leverage the
weakly annotated images. Specifically, two consistency properties are learned:
multi-source consistency (MSC) and inter-patch consistency (IPC). MSC exploits
different content-agnostic information and enables cross-source learning via an
online pseudo label generation and refinement process. IPC performs global
pair-wise patch-patch relationship reasoning to discover a complete region of
manipulation. Extensive experiments validate that our WSCL, even though is
weakly supervised, exhibits competitive performance compared with
fully-supervised counterpart under both in-distribution and out-of-distribution
evaluations, as well as reasonable manipulation localization ability.Comment: Accepted to ICCV 2023, code: https://github.com/yhZhai/WSC
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Long non-coding RNA profiling of human lymphoid progenitor cells reveals transcriptional divergence of B cell and T cell lineages.
To elucidate the transcriptional 'landscape' that regulates human lymphoid commitment during postnatal life, we used RNA sequencing to assemble the long non-coding transcriptome across human bone marrow and thymic progenitor cells spanning the earliest stages of B lymphoid and T lymphoid specification. Over 3,000 genes encoding previously unknown long non-coding RNAs (lncRNAs) were revealed through the analysis of these rare populations. Lymphoid commitment was characterized by lncRNA expression patterns that were highly stage specific and were more lineage specific than those of protein-coding genes. Protein-coding genes co-expressed with neighboring lncRNA genes showed enrichment for ontologies related to lymphoid differentiation. The exquisite cell-type specificity of global lncRNA expression patterns independently revealed new developmental relationships among the earliest progenitor cells in the human bone marrow and thymus
Desmosomal cadherins in zebrafish epiboly and gastrulation
<p>Abstract</p> <p>Background</p> <p>The desmosomal cadherins (DCs), desmocollin (Dsc) and desmoglein (Dsg), are the adhesion molecules of desmosomes, intercellular adhesive junctions of epithelia and cardiac muscle. Both the DCs and desmosomes have demonstrably essential roles in mammalian development. In order to initiate their study in a more tractable developmental system we have characterised zebrafish DCs and examined their roles in early zebrafish development.</p> <p>Results</p> <p>We find that zebrafish possess one Dsc, the orthologue of mammalian Dsc1, which we designate zfDsc. Unlike mammalian Dscs, zfDsc exists only as the "a" form since it lacks the alternatively-spliced mini-exon that shortens the cytoplasmic domain to produce the "b" form. Zebrafish possess two Dsgs, designated zfDsgα and zfDsgβ, orthologues of mammalian Dsg2. They show 43.8% amino acid identity and the α form has a 43 amino acid glycine-rich sequence of unknown function in its extracellular domain. Both zfDsc and zfDsgα were present as maternal and zygotic transcripts whereas zfDsgβ was first expressed from 8 hours post-fertilisation (hpf). All three transcripts were present throughout subsequent stages of development. Morpholino knockdown of both zfDsc and zfDsgα expression produced similar defects in epiboly, axis elongation and somite formation, associated with abnormal desmosomes or reduced desmosome numbers.</p> <p>Conclusions</p> <p>These results demonstrate an important role for DCs and desmosomes in the early morphogenesis of the zebrafish embryo, provide a basis for more detailed analysis of their role and raise interesting questions relating to the evolution and functional significance of DC isoforms.</p
Desmosomal cadherins in zebrafish epiboly and gastrulation
<p>Abstract</p> <p>Background</p> <p>The desmosomal cadherins (DCs), desmocollin (Dsc) and desmoglein (Dsg), are the adhesion molecules of desmosomes, intercellular adhesive junctions of epithelia and cardiac muscle. Both the DCs and desmosomes have demonstrably essential roles in mammalian development. In order to initiate their study in a more tractable developmental system we have characterised zebrafish DCs and examined their roles in early zebrafish development.</p> <p>Results</p> <p>We find that zebrafish possess one Dsc, the orthologue of mammalian Dsc1, which we designate zfDsc. Unlike mammalian Dscs, zfDsc exists only as the "a" form since it lacks the alternatively-spliced mini-exon that shortens the cytoplasmic domain to produce the "b" form. Zebrafish possess two Dsgs, designated zfDsgα and zfDsgβ, orthologues of mammalian Dsg2. They show 43.8% amino acid identity and the α form has a 43 amino acid glycine-rich sequence of unknown function in its extracellular domain. Both zfDsc and zfDsgα were present as maternal and zygotic transcripts whereas zfDsgβ was first expressed from 8 hours post-fertilisation (hpf). All three transcripts were present throughout subsequent stages of development. Morpholino knockdown of both zfDsc and zfDsgα expression produced similar defects in epiboly, axis elongation and somite formation, associated with abnormal desmosomes or reduced desmosome numbers.</p> <p>Conclusions</p> <p>These results demonstrate an important role for DCs and desmosomes in the early morphogenesis of the zebrafish embryo, provide a basis for more detailed analysis of their role and raise interesting questions relating to the evolution and functional significance of DC isoforms.</p
Summed Parallel Infinite Impulse Response (SPIIR) Filters For Low-Latency Gravitational Wave Detection
With the upgrade of current gravitational wave detectors, the first detection
of gravitational wave signals is expected to occur in the next decade.
Low-latency gravitational wave triggers will be necessary to make fast
follow-up electromagnetic observations of events related to their source, e.g.,
prompt optical emission associated with short gamma-ray bursts. In this paper
we present a new time-domain low-latency algorithm for identifying the presence
of gravitational waves produced by compact binary coalescence events in noisy
detector data. Our method calculates the signal to noise ratio from the
summation of a bank of parallel infinite impulse response (IIR) filters. We
show that our summed parallel infinite impulse response (SPIIR) method can
retrieve the signal to noise ratio to greater than 99% of that produced from
the optimal matched filter. We emphasise the benefits of the SPIIR method for
advanced detectors, which will require larger template banks.Comment: 9 pages, 6 figures, for PR
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