916 research outputs found
The Effect of Temperature on the Susceptibility of Eastern Newts to Two Lethal Pathogens
Undergraduate
Basi
Adverse Aftereffects of Methotrexate as Chemotherapy on Cognitive Deficits in Rat Models
Patients with acute lymphoblastic leukemia have a high five-year survival rate thanks to methotrexate (MTX). However, cognitive side effects are reported, characterized as chemo brain. The study investigated if impulsiveness is part of the aberrant cognitive functions after being exposed to MTX in the early stage of physical development. Adolescent rats were injected with either phosphate-buffered saline (PBS) or MTX. The novel object recognition (NOR) task was conducted a month after the injections to measure the memory deficits. The discounting task was performed after the rats completed training on a fixed-ratio one schedule for both levers. The NOR test showed both the PBS and MTX rats recognized the novel object; however, the PBS group spent more time inspecting the novel object than the MTX group. Initial results from two rats (one from each group) for the discounting task showed that the PBS-treated rat preferred the immediate reward at the beginning and had increased omissions during the later trials. The MTX rat showed a consistent preference for the immediate lever across the entire procedure. These composite findings suggested cognitive deficits are not apparent within one month of MTX treatment, yet the impulsiveness is more apparent after MTX exposure
Queue-Architecture and Stability Analysis in Cooperative Relay Networks
An abstraction of the physical layer coding using bit pipes that are coupled
through data-rates is insufficient to capture notions such as node cooperation
in cooperative relay networks. Consequently, network-stability analyses based
on such abstractions are valid for non-cooperative schemes alone and
meaningless for cooperative schemes. Motivated from this, this paper develops a
framework that brings the information-theoretic coding scheme together with
network-stability analysis. This framework does not constrain the system to any
particular achievable scheme, i.e., the relays can use any cooperative coding
strategy of its choice, be it amplify/compress/quantize or any
alter-and-forward scheme. The paper focuses on the scenario when coherence
duration is of the same order of the packet/codeword duration, the channel
distribution is unknown and the fading state is only known causally. The main
contributions of this paper are two-fold: first, it develops a low-complexity
queue-architecture to enable stable operation of cooperative relay networks,
and, second, it establishes the throughput optimality of a simple network
algorithm that utilizes this queue-architecture.Comment: 16 pages, 1 figur
Backtracking Spatial Pyramid Pooling (SPP)-based Image Classifier for Weakly Supervised Top-down Salient Object Detection
Top-down saliency models produce a probability map that peaks at target
locations specified by a task/goal such as object detection. They are usually
trained in a fully supervised setting involving pixel-level annotations of
objects. We propose a weakly supervised top-down saliency framework using only
binary labels that indicate the presence/absence of an object in an image.
First, the probabilistic contribution of each image region to the confidence of
a CNN-based image classifier is computed through a backtracking strategy to
produce top-down saliency. From a set of saliency maps of an image produced by
fast bottom-up saliency approaches, we select the best saliency map suitable
for the top-down task. The selected bottom-up saliency map is combined with the
top-down saliency map. Features having high combined saliency are used to train
a linear SVM classifier to estimate feature saliency. This is integrated with
combined saliency and further refined through a multi-scale
superpixel-averaging of saliency map. We evaluate the performance of the
proposed weakly supervised topdown saliency and achieve comparable performance
with fully supervised approaches. Experiments are carried out on seven
challenging datasets and quantitative results are compared with 40 closely
related approaches across 4 different applications.Comment: 14 pages, 7 figure
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