931 research outputs found
Mirasol3B: A Multimodal Autoregressive model for time-aligned and contextual modalities
One of the main challenges of multimodal learning is the need to combine
heterogeneous modalities (e.g., video, audio, text). For example, video and
audio are obtained at much higher rates than text and are roughly aligned in
time. They are often not synchronized with text, which comes as a global
context, e.g., a title, or a description. Furthermore, video and audio inputs
are of much larger volumes, and grow as the video length increases, which
naturally requires more compute dedicated to these modalities and makes
modeling of long-range dependencies harder.
We here decouple the multimodal modeling, dividing it into separate, focused
autoregressive models, processing the inputs according to the characteristics
of the modalities. We propose a multimodal model, called Mirasol3B, consisting
of an autoregressive component for the time-synchronized modalities (audio and
video), and an autoregressive component for the context modalities which are
not necessarily aligned in time but are still sequential. To address the
long-sequences of the video-audio inputs, we propose to further partition the
video and audio sequences in consecutive snippets and autoregressively process
their representations. To that end, we propose a Combiner mechanism, which
models the audio-video information jointly within a timeframe. The Combiner
learns to extract audio and video features from raw spatio-temporal signals,
and then learns to fuse these features producing compact but expressive
representations per snippet.
Our approach achieves the state-of-the-art on well established multimodal
benchmarks, outperforming much larger models. It effectively addresses the high
computational demand of media inputs by both learning compact representations,
controlling the sequence length of the audio-video feature representations, and
modeling their dependencies in time
Copper(II) Complexes of Coumarin-Derived Schiff Bases and their anti-Candida Activity
The condensation of 7-amino-4-methyl-coumarin (1) with a number of substituted salicylaldehydes yielded a series of Schiff bases (2a–2k) in good yields. Subsequent reaction of these ligands with copper( II) acetate yielded Cu(II) complexes (3a–3k) and some were characterised using X-ray crystallography. All of the free ligands and their metal complexes were tested for their anti-Candida activity
Copper(II) complexes of coumarin-derived Schiff bases and their anti-Candida activity.
The condensation of 7-amino-4-methyl-coumarin (1) with a number of substituted salicylaldehydes
yielded a series of Schiff bases (2a–2k) in good yields. Subsequent reaction of these ligands with copper(
II) acetate yielded Cu(II) complexes (3a–3k) and some were characterised using X-ray crystallography.
All of the free ligands and their metal complexes were tested for their anti-Candida activity. A
number of the ligands and complexes exhibited anti-Candida activity comparable to that of the commercially
available antifungal drugs, ketoconazole and Amphotericin B
Bifurcations of discrete breathers in a diatomic Fermi-Pasta-Ulam chain
Discrete breathers are time-periodic, spatially localized solutions of the
equations of motion for a system of classical degrees of freedom interacting on
a lattice. Such solutions are investigated for a diatomic Fermi-Pasta-Ulam
chain, i. e., a chain of alternate heavy and light masses coupled by anharmonic
forces. For hard interaction potentials, discrete breathers in this model are
known to exist either as ``optic breathers'' with frequencies above the optic
band, or as ``acoustic breathers'' with frequencies in the gap between the
acoustic and the optic band. In this paper, bifurcations between different
types of discrete breathers are found numerically, with the mass ratio m and
the breather frequency omega as bifurcation parameters. We identify a period
tripling bifurcation around optic breathers, which leads to new breather
solutions with frequencies in the gap, and a second local bifurcation around
acoustic breathers. These results provide new breather solutions of the FPU
system which interpolate between the classical acoustic and optic modes. The
two bifurcation lines originate from a particular ``corner'' in parameter space
(omega,m). As parameters lie near this corner, we prove by means of a center
manifold reduction that small amplitude solutions can be described by a
four-dimensional reversible map. This allows us to derive formally a continuum
limit differential equation which characterizes at leading order the
numerically observed bifurcations.Comment: 30 pages, 10 figure
Role of cell cycle events and apoptosis in mediating the anti-cancer activity of a silver(I) complex of 4-hydroxy-3-nitro-coumarin-bis(phenanthroline) in human malignant cancer cells.
The central objective of the current study was to investigate the potential in vitro anti-proliferative effect of
4-hydroxy-3-nitro-coumarin (hncH), and the mixed-ligand silver (I) complex of 4-oxy-3-nitro-coumarin-bis
(phenanthroline), [Ag(hnc)(phen)2] using four human-derived model cell lines. In addition, selected
mechanistic studies were carried out using the most sensitive of the four cell lines. Results obtained show
that the complex could decrease the proliferation of all four cell lines including neoplastic renal and hepatic,
namely A-498 and HepG2 cells, respectively, along with two non-neoplastic renal and hepatic cell lines, HK-2
and Chang, respectively. Furthermore, non-neoplastic hepatic cells (Chang) appeared to be less sensitive to
the effect of the complex, but this effect was not replicated in the non-neoplastic renal (HK-2) cells. Based on
IC50 values [Ag(hnc)(phen)2] was shown to be almost four times more potent than cisplatin, using HepG2
cells. In addition, the observed anti-proliferative effect was shown to be both dose- and time-dependent.
Furthermore, the complex was shown to decrease DNA synthesis, but did not intercalate with it. Moreover,
there was no evidence that P-glycoprotein-mediated multi-drug resistance was likely to decrease antiproliferative
activity. Cytological stains, analysis of genomic DNA, and biochemical assays [caspase-3 and -9
and cleaved poly(ADP-ribose)-polymerase protein] showed that cell death appeared to result from apoptosis,
with the possibility of secondary necrosis. Additionally, flow cytometric analysis showed that the complex
functioned through an alteration in cell cycle progression. Taken together, [Ag(hnc)(phen)2] has been shown
to be a more potent anti-proliferative agent than cisplatin, capable of altering key biochemical events leading
to cell death. Additional mechanistic studies are underway to probe more fully its mechanism of action
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