4,452 research outputs found
An Empirical Study of Small and Medium Enterprises Website Continuance Intention Determinants in Malaysia
Penyelidikan faktor yang menyebabkan penggunaan teknologi Internet telah menjadi topik tinjauan
yang popular sejak kebelakangan, terutamanya dari sudut pandangan pengguna.
The study of Internet technology adoption antecedents has been a popular research topic in recent
years, especially from the consumer market research domain
Traveling waves in lattice differential equations with distributed maturation delay
In this paper we derive a lattice model with infinite distributed delay to describe the growth of a single-species population in a 2D patchy environment with infinite number of patches connected locally by diffusion and global interaction. We consider the existence of traveling wave solutions when the birth rate is large enough that each patch can sustain a positive equilibrium. When the birth function is monotone, we prove that there exists a traveling wave solution connecting two equilibria with wave speed by using the monotone iterative method and super and subsolution technique, where is any fixed direction of propagation. When the birth function is non-monotone, we prove the existence of non-trivial traveling wave solutions by constructing two auxiliary systems satisfying quasi-monotonicity
Affinity Uncertainty-based Hard Negative Mining in Graph Contrastive Learning
Hard negative mining has shown effective in enhancing self-supervised
contrastive learning (CL) on diverse data types, including graph CL (GCL). The
existing hardness-aware CL methods typically treat negative instances that are
most similar to the anchor instance as hard negatives, which helps improve the
CL performance, especially on image data. However, this approach often fails to
identify the hard negatives but leads to many false negatives on graph data.
This is mainly due to that the learned graph representations are not
sufficiently discriminative due to oversmooth representations and/or
non-independent and identically distributed (non-i.i.d.) issues in graph data.
To tackle this problem, this article proposes a novel approach that builds a
discriminative model on collective affinity information (i.e., two sets of
pairwise affinities between the negative instances and the anchor instance) to
mine hard negatives in GCL. In particular, the proposed approach evaluates how
confident/uncertain the discriminative model is about the affinity of each
negative instance to an anchor instance to determine its hardness weight
relative to the anchor instance. This uncertainty information is then
incorporated into the existing GCL loss functions via a weighting term to
enhance their performance. The enhanced GCL is theoretically grounded that the
resulting GCL loss is equivalent to a triplet loss with an adaptive margin
being exponentially proportional to the learned uncertainty of each negative
instance. Extensive experiments on ten graph datasets show that our approach
does the following: 1) consistently enhances different state-of-the-art (SOTA)
GCL methods in both graph and node classification tasks and 2) significantly
improves their robustness against adversarial attacks. Code is available at
https://github.com/mala-lab/AUGCL.Comment: Accepted to TNNL
Hydrogen sulfide ameliorates isoflurane-induced cognitive impairment in mice: Implication of caspase-3 activation
Purpose: Isoflurane could induce cognitive impairment and activate caspase-3. However, the mechanism of action is unclear and target interventions are unavailable. The present study examined the potential protective function of hydrogen sulfide (H2S) against isoflurane-induced cognitive impairment.Methods: Effects of NaHS (5 mg/kg) on cognitive impairment induced by isoflurane (1.4% for 2 h) were assessed using a fear-conditioning test in a group of 8-month old mice. H4 human neuroglioma cells, which were transfected with upregulated human amyloid precursor protein were treated for 3 or 6 h with 2% isoflurane, in the presence of 100-μM NaHS in the mice. A group of mice treated with normal saline in place of the NaHS in each case served as control. Western blotting, fluorescence assay, and a mitochondrial swelling assay were employed to observe the results of caspase-3 activation, mitochondrial dysfunction, and ROS and ATP levels.Results: NaHS significantly mitigated isoflurane-induced cognitive impairment in mice. In cultured cells, NaHS reduced caspase-3 activation, ROS, mitochondria membrane reduction, mitochondrial permeability transition pore opening, and cellular ATP level. NaHS could ameliorate cognitiveimpariment induced by isoflurane through inhibiting caspase-3 activation, oxidative stress, and mitochondrial dysfunction.Conclusion: These results indicate that hydrogen sulfide (H2S) has potential protective function against isoflurane-induced cognitive impairment. Further investigation of NaHS as an intervention to attenuate anesthesia-associated neurotoxicity is vital.
Keywords: Hydrogen sulfide, isoflurane-cognition,fear conditioning,neurotoxicit
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