Traffic flow densities in large transport networks

We consider transport networks with nodes scattered at random in a large domain. At certain local rates, the nodes generate traffic flowing according to some navigation scheme in a given direction. In the thermodynamic limit of a growing domain, we present an asymptotic formula expressing the local traffic flow density at any given location in the domain in terms of three fundamental characteristics of the underlying network: the spatial intensity of the nodes together with their traffic generation rates, and of the links induced by the navigation. This formula holds for a general class of navigations satisfying a link-density and a sub-ballisticity condition. As a specific example, we verify these conditions for navigations arising from a directed spanning tree on a Poisson point process with inhomogeneous intensity function.Comment: 20 pages, 7 figure

Large deviations in relay-augmented wireless networks

We analyze a model of relay-augmented cellular wireless networks. The network users, who move according to a general mobility model based on a Poisson point process of continuous trajectories in a bounded domain, try to communicate with a base station located at the origin. Messages can be sent either directly or indirectly by relaying over a second user. We show that in a scenario of an increasing number of users, the probability that an atypically high number of users experiences bad quality of service over a certain amount of time, decays at an exponential speed. This speed is characterized via a constrained entropy minimization problem. Further, we provide simulation results indicating that solutions of this problem are potentially non-unique due to symmetry breaking. Also two general sources for bad quality of service can be detected, which we refer to as isolation and screening.Comment: 28 pages, 5 figures; corrected several misprint

Large-deviation principles for connectable receivers in wireless networks

We study large-deviation principles for a model of wireless networks consisting of Poisson point processes of transmitters and receivers, respectively. To each transmitter we associate a family of connectable receivers whose signal-to-interference-and-noise ratio is larger than a certain connectivity threshold. First, we show a large-deviation principle for the empirical measure of connectable receivers associated with transmitters in large boxes. Second, making use of the observation that the receivers connectable to the origin form a Cox point process, we derive a large-deviation principle for the rescaled process of these receivers as the connection threshold tends to zero. Finally, we show how these results can be used to develop importance-sampling algorithms that substantially reduce the variance for the estimation of probabilities of certain rare events such as users being unable to connectComment: 29 pages, 2 figure

Ghosts: An Artistic Meditation on the Holocaust and Anti-Semitism

Samuel and Bettie Roberts Lecture in Jewish Art… Robert Hirsch, Artist and photographic historian, in conjunction with his exhibition, at Fairfield University Art Museum\u27s Walsh Gallery.https://digitalcommons.fairfield.edu/bennettcenter-posters/1356/thumbnail.jp

Dissection of Gray Leaf Spot of Maize Through Functional Genomics

Gray leaf spot, caused by Cercospora zeae-maydis, is a devastating disease of maize that reduces yields and increases management costs. C. zeae-maydis penetrates maize leaves through stomata, but the biological and molecular bases of this process are poorly understood. The goal of this research was to elucidate the biological parameters of stomatal infection in C. zeae-maydis, and to identify and characterize novel genetic pathways involved in stomatal sensing and pathogenesis. Histopathological observations of a GFP-expressing strain of C. zeae-maydis during infection of maize indicated that the fungus responded to host-derived stomatal cues during the infection process. C. zeae-maydis was observed exhibiting tropism toward non-host stomata, which ultimately implicated molecular oxygen as a possible stomatal chemoattractant. To explore the role of circadian rhythmicity in gray leaf spot, the putative central circadian oscillator gene FRQ in C. zeae-maydis was functionally disrupted and characterized. Interestingly, FRQ deletion strains were non-pathogenic when inoculated on maize leaves. Histological observations suggested that FRQ deletion strains failed to form appressoria in association with maize stomata. In order to identify other novel genes involved in pathogenesis, a collection of 1228 insertional mutants was created and assayed for infectious development. Ten mutants were identified, including one that was disrupted in RJP1, a putative epigenetic regulator of gene expression. In a related study, thirty-one genes were selected for functional disruption based on sequence similarity to known fungal regulatory genes. Analysis of these mutants indicated that GPA2, which encodes a putative G protein alpha subunit, was required for pathogenesis. Lastly, gene expression analysis during pre-penetration infectious development revealed widespread transcriptional reprogramming. Key findings from this research include the discovery of novel pathogenesis-related genes and potential roles for oxygen sensing and the fungal circadian clock in foliar pathogenesis. Furthermore, this research illuminated a previously unrecognized level of complexity underlying the regulation of stomatal infection during gray leaf spot of maize and established a foundation for future molecular investigations

Walking in the Free World

Two of the nation\u27s most scenic wilderness trails provide the backdrop for a young man\u27s journey of discovery

Orbit Spaces of Gradient Vector Fields

We study orbit spaces of generalized gradient vector fields for Morse functions. Typically, these orbit spaces are non-Hausdorff. Nevertheless, they are quite structured topologically and are amenable to study. We show that these orbit spaces are locally contractible. We also show that the quotient map associated to each such orbit space is a weak homotopy equivalence and has the path lifting property.Comment: 16 pages, 4 figures; strengthened a main result (Corollary 3.5) and updated the introduction and the conclusio

What to Do When the Lab Closes? Managing an Interdisciplinary, Undergraduate Research Capstone Course During a Global Pandemic

Excerpt The Agricultural and Medical Biotechnology (ABT) program at the University of Kentucky’s College of Agriculture, Food and Environment is a genetics-based, research-intensive, interdisciplinary program that consistently produces undergraduate scholars prepared for careers in research, medicine, and other health-related industries. The program enrolls approximately 250 students and is administered around a liberal philosophy of interdisciplinarity, with undergraduates encouraged to build their own individualized curricula centered on foundational courses in biology, chemistry, and genetics. This student-centric approach, combined with an array of faculty research foci, results in a diverse student body engaging in scholarship that ranges from human neurobiology to plant rhizosphere metagenomics

Consommation et approvisionnements en denrées alimentaires

La sociologie économique permet de réinterroger le lien entre production et consommation. Ce lien s’est historiquement construit à partir des pratiques de production et de consommation, mais également des pratiques commerciales. Il est mis aujourd’hui en débat à la fois dans le contexte de la reconstruction de la confiance après les crises sanitaires et dans le cadre de la mise en oeuvre de propositions émanant de collectifs issus de la société civile. Le lien entre production et consommation peut s’appréhender à la fois sous l’angle des compétences, et notamment celles des consommateurs – comment les consommateurs se repèrent-ils dans l’offre alimentaire ? –, mais également à travers les formes de gouvernance qui s’exercent au sein des systèmes alimentaires – qui participe aux décisions quant aux choix qui sont faits pour ces systèmes ? Il convient tout d’abord de revenir sur la construction historique des modes d’approvisionnement des denrées alimentaires, pour comprendre comment les consommateurs ont progressivement appris à choisir et acheter des produits alimentaires dont ils ne connaissent pas les modes de production. On explicitera ensuite les réponses apportées par les systèmes alimentaires aux crises alimentaires et les propositions, visant à réinterroger cette relation entre producteurs et consommateurs, faites par des mouvements sociaux