York University

About: York University is a education organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Population & Politics. The organization has 18899 authors who have published 43357 publications receiving 1568560 citations.

Vehicle Routing Problems for Drone Delivery

Abstract: Unmanned aerial vehicles, or drones, have the potential to significantly reduce the cost and time of making last-mile deliveries and responding to emergencies. Despite this potential, little work has gone into developing vehicle routing problems (VRPs) specifically for drone delivery scenarios. Existing VRPs are insufficient for planning drone deliveries: either multiple trips to the depot are not permitted, leading to solutions with excess drones, or the effect of battery and payload weight on energy consumption is not considered, leading to costly or infeasible routes. We propose two multitrip VRPs for drone delivery that address both issues. One minimizes costs subject to a delivery time limit, while the other minimizes the overall delivery time subject to a budget constraint. We mathematically derive and experimentally validate an energy consumption model for multirotor drones, demonstrating that energy consumption varies approximately linearly with payload and battery weight. We use this approximation to derive mixed integer linear programs for our VRPs. We propose a cost function that considers our energy consumption model and drone reuse, and apply it in a simulated annealing (SA) heuristic for finding suboptimal solutions to practical scenarios. To assist drone delivery practitioners with balancing cost and delivery time, the SA heuristic is used to show that the minimum cost has an inverse exponential relationship with the delivery time limit, and the minimum overall delivery time has an inverse exponential relationship with the budget. Numerical results confirm the importance of reusing drones and optimizing battery size in drone delivery VRPs.

The induction of micronuclei as a measure of genotoxicity: A report of the U.S. environmental protection agency Gene-Tox program☆

Abstract: There are many possible micronucleus assays involving different test organisms and tissues. Because micronuclei arise from chromosomal fragments or chromosomes that are not incorporated into daughter nuclei at the time of cell division, the assay detects both clastogens and agents that affect the spindle apparatus. We know of no case in which micronuclei and chromosomal breakage (or loss) have been shown to occur independently of one another in any dividing cell population. This relationship is so close that false-positives and false-negatives (insofar as the detection of tissue-specific chromosome damage is concerned) should be determined primarily by the statistics of sampling. The production of micronuclei in various experimental organisms has been reviewed. Although there are several promising experimental approaches such as the use of meiotic plant cells or human cells in culture, only one form of the assay, the in vivo mammalian bone-marrow polychromatic erythrocyte (PCE) assay, has been sufficiently developed to be considered a standard assay. More than 150 chemicals have been tested in this assay, with varying degrees of rigor. The data from the literature have been summarized and evaluated in light of the work Group's recommendations for an adequate test. The standards for an adequate test are an important part of the recommendations. These standards, although based on the most recent information available to us, are subject to change because this assay is still evolving. The most important recommendations in this report are: (1) at least 500 PCE should be examined from each of 8 animals to detect an increase of about 4‰ (per thousand) PCE when the background is less than 4 per 1000, (2) sampling should be extended to at least 72 h after the initial treatment, with sampling intervals no greater than 24 h, and (3) the highest possible doses should be used. The success rate of the assay to detect chemicals designated by the Environmental Protection Agency (EPA) as carcinogens is difficult to estimate for several reasons. First, few chemicals designated as noncarcinogens were studied, although in routine testing noncarcinogens are expected to be much more common than carcinogens. Hence, the rate of false-positives (insofar as the detection of cancer is concerned), which ought to be one of the strongest features of the assays, could not be estimated. Second, few chemicals have been tested as rigorously as this report recommends. Hence, the rate of false-negatives is almost certainly overestimated. (It is, nevertheless, obvious that false-negatives are to be expected for any tissue-specific in vivo assay like the micronucleus assay. For example diethylnitrosamine, which produces chromosomal aberrations, micronuclei, and cancer in the liver, is not detected in the bone-marrow micronucleus assay.) Third, many carcinogens are species-specific and this fact has not been taken into account. Considering these caveats, the uncorrected detection rate of the chemicals designated as carcinogens by EPA is about 50%. We believe that this would have been significantly higher had all tests been performed according to the test criteria. Further improvements in the assay are to be expected and these may lead to improvements in its success rate. Recent developments are discussed.

The Toronto Empathy Questionnaire: Scale development and initial validation of a factor-analytic solution to multiple empathy measures

Abstract: To formulate a parsimonious tool to assess empathy, we used factor analysis on a combination of self-report measures to examine consensus and developed a brief self-report measure of this common factor. The Toronto Empathy Questionnaire (TEQ) represents empathy as a primarily emotional process. In 3 studies, the TEQ demonstrated strong convergent validity, correlating positively with behavioral measures of social decoding, self-report measures of empathy, and negatively with a measure of Autism symptomatology. Moreover, it exhibited good internal consistency and high test-retest reliability. The TEQ is a brief, reliable, and valid instrument for the assessment of empathy.

International consensus classification of hippocampal sclerosis in temporal lobe epilepsy: A Task Force report from the ILAE Commission on Diagnostic Methods

Abstract: Hippocampal sclerosis (HS) is the most frequent histopathology encountered in patients with drug-resistant temporal lobe epilepsy (TLE). Over the past decades, various attempts have been made to classify specific patterns of hippocampal neuronal cell loss and correlate subtypes with postsurgical outcome. However, no international consensus about definitions and terminology has been achieved. A task force reviewed previous classification schemes and proposes a system based on semiquantitative hippocampal cell loss patterns that can be applied in any histopathology laboratory. Interobserver and intraobserver agreement studies reached consensus to classify three types in anatomically well-preserved hippocampal specimens: HS International League Against Epilepsy (ILAE) type 1 refers always to severe neuronal cell loss and gliosis predominantly in CA1 and CA4 regions, compared to CA1 predominant neuronal cell loss and gliosis (HS ILAE type 2), or CA4 predominant neuronal cell loss and gliosis (HS ILAE type 3). Surgical hippocampus specimens obtained from patients with TLE may also show normal content of neurons with reactive gliosis only (no-HS). HS ILAE type 1 is more often associated with a history of initial precipitating injuries before age 5 years, with early seizure onset, and favorable postsurgical seizure control. CA1 predominant HS ILAE type 2 and CA4 predominant HS ILAE type 3 have been studied less systematically so far, but some reports point to less favorable outcome, and to differences regarding epilepsy history, including age of seizure onset. The proposed international consensus classification will aid in the characterization of specific clinicopathologic syndromes, and explore variability in imaging and electrophysiology findings, and in postsurgical seizure control. © 2013 Wiley Periodicals, Inc.