Carleton University

About: Carleton University is a education organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 15852 authors who have published 39650 publications receiving 1106610 citations.

Joint Optimization of Caching, Computing, and Radio Resources for Fog-Enabled IoT Using Natural Actor–Critic Deep Reinforcement Learning

Abstract: The cloud-based Internet of Things (IoT) develops rapidly but suffer from large latency and backhaul bandwidth requirement, the technology of fog computing and caching has emerged as a promising paradigm for IoT to provide proximity services, and thus reduce service latency and save backhaul bandwidth. However, the performance of the fog-enabled IoT depends on the intelligent and efficient management of various network resources, and consequently the synergy of caching, computing, and communications becomes the big challenge. This paper simultaneously tackles the issues of content caching strategy, computation offloading policy, and radio resource allocation, and propose a joint optimization solution for the fog-enabled IoT. Since wireless signals and service requests have stochastic properties, we use the actor–critic reinforcement learning framework to solve the joint decision-making problem with the objective of minimizing the average end-to-end delay. The deep neural network (DNN) is employed as the function approximator to estimate the value functions in the critic part due to the extremely large state and action space in our problem. The actor part uses another DNN to represent a parameterized stochastic policy and improves the policy with the help of the critic. Furthermore, the Natural policy gradient method is used to avoid converging to the local maximum. Using the numerical simulations, we demonstrate the learning capacity of the proposed algorithm and analyze the end-to-end service latency.

Genomic Signatures Predict Migration and Spawning Failure in Wild Canadian Salmon

Abstract: Long-term population viability of Fraser River sockeye salmon (Oncorhynchus nerka) is threatened by unusually high levels of mortality as they swim to their spawning areas before they spawn. Functional genomic studies on biopsied gill tissue from tagged wild adults that were tracked through ocean and river environments revealed physiological profiles predictive of successful migration and spawning. We identified a common genomic profile that was correlated with survival in each study. In ocean-tagged fish, a mortality-related genomic signature was associated with a 13.5-fold greater chance of dying en route. In river-tagged fish, the same genomic signature was associated with a 50% increase in mortality before reaching the spawning grounds in one of three stocks tested. At the spawning grounds, the same signature was associated with 3.7-fold greater odds of dying without spawning. Functional analysis raises the possibility that the mortality-related signature reflects a viral infection.

Calpain-regulated p35/cdk5 plays a central role in dopaminergic neuron death through modulation of the transcription factor myocyte enhancer factor 2.

Abstract: The mechanisms underlying dopamine neuron loss in Parkinson's disease (PD) are not clearly defined. Here, we delineate a pathway by which dopaminergic loss induced by 1-methyl-4-phenyl 1,2,3,6 tetrahydropyridine (MPTP) is controlled in vivo. We reported previously that calpains play a central required role in dopamine loss after MPTP treatment. Here, we provide evidence that the downstream effector pathway of calpains is through cyclin-dependent kinase 5 (cdk5)-mediated modulation of the transcription factor myocyte enhancer factor 2 (MEF2). We show that MPTP-induced conversion of the cdk5 activator p35 to a pathogenic p25 form is dependent on calpain activity in vivo. In addition, p35 deficiency attenuates MPTP-induced dopamine neuron loss and behavioral outcome. Moreover, MEF2 is phosphorylated on Ser444, an inactivating site, after MPTP treatment. This phosphorylation is dependent on both calpain and p35 activity, consistent with the model that calpain-mediated activation of cdk5 results in phosphorylation of MEF2 in vivo. Finally, we provide evidence that MEF2 is critical for dopaminergic loss because "cdk5 phosphorylation site mutant" of MEF2D provides neuroprotection in an MPTP mouse model of PD. Together, these data indicate that calpain-p35-p25/cdk5-mediated inactivation of MEF2 plays a critical role in dopaminergic loss in vivo.

RF amplifier, RF mixer and RF receiver

Abstract: A low voltage silicon bipolar RF (radio frequency) receiver front end includes a low noise preamplifier and double-balanced mixer. The receiver incorporates monolithic microstrip transformers for significant improvements in performance compared with silicon broadband designs. Reactive feedback and coupling elements are used in place of resistors to lower the front end noise figure through the reduction of resistor thermal noise, and this also allows both circuits to operate at supply voltages below 2 volts. Circuits fabricated using 0.8 μm Bipolar CMOS technology provide a peak npn transistor transit frequency fT of 11 GHz. At a supply voltage of 1.9 volts, the measured input third order intercept point is +2.3 dBm with a 10.9 dB single-sideband noise figure. Power dissipated is less than 5 mW. The low noise amplifier input intercept is -3 dBm with a 2.8 dB noise figure and 0.5 dB gain. Power dissipation of the preamplifier is less than 4 mW from a 1.9 V supply.

Homology and phylogenetic implications of male genitalia in Diptera - Eremoneura

Abstract: Homologies of male genitalic structures in the Eremoneura (Empidoidea + Cyclorrhapha) are examined and implications for the phylogenetic relationships of the included families are discussed in light of other characters. A revised epandrial hypothesis for the evolution of male genitalia within the Eremoneura is presented, based on comparison of male genitalic features throughout the Brachycera, and a periandrial hypothesis is rejected. Ground plan modifications of the genitalia of Eremoneura include complete sclerotization of the subepandrial membrane along its length to form a subepandrial sclerite, formation of bacilliform sclerites, loss of the lateral ejaculatory processes of the sperm pump, development of a deeply emarginate epandrium, and fusion of the hypandrium with the gonocoxites. Ground plan apomorphies of the Cyclorrhapha, including Opetiidae, consist of a sperm pump separated from the base of the phallus, circumversion of the genitalia, loss of the gonocoxal apodemes, and development of surstyli. The ground plan of the Empidoidea is characterized by the apomorphic loss of gonostyli, and the development of a sperm pump with a lever-like ejaculatory apodeme. Surstyli have developed independently in several lineages of Empidoidea, parallel to their development in Cyclorrhapha, as have losses of the gonocoxal apodemes. The above characters support the monophyly of the Eremoneura and also indicate that the Empidoidea and Cyclorrhapha are sister groups, as opposed to alternative hypotheses that suggest the Empidoidea is paraphyletic with respect to the Cyclorrhapha. The monophyly of Cyclorrhapha, exclusive of Opetiidae, is supported by the presence of a phallapodeme. The Lonchopteridae and Phoroidea are united partially on the basis of a similar reduction of pregenital sclerites in the male. The Phoroidea is characterized by the apomorphic loss of gonostyli and abdominal spiracle 7 in the male. The Syrphoidea and Schizophora are hypothesized to share a synapomorphic lever-like phallapodeme. The Syrphoidea is characterized by a right-side deflexion of the hypopygium, whereas the Schizophora possess gonostyli that are adducted against the hypandrium, and circumversion that is completed entirely within the puparium.