1,950 research outputs found

    Corrections, clarifications, and additions to the 1996 checklist of the Alticinae of Central America : including Mexico (Coleoptera: Chrysomelidae)

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    In our checklist of the Alticinae of Central America and Mexico (Furth and Savini, 1996), there were some species whose status or generic combination needs clarification. In preparing the 1996 checklist the authors referred to some unpublished notes of Jan Bechyne in order to understand his system of alticine names and to clarify to which genera he considered various species to belong

    Data conditioning and display for Apollo prelaunch checkout - Test matrix technique

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    Test matrix technique for checkout and launching of Apollo-Saturn spacecraf

    Low-Stress Bicycling and Network Connectivity

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    For a bicycling network to attract the widest possible segment of the population, its most fundamental attribute should be low-stress connectivity, that is, providing routes between people’s origins and destinations that do not require cyclists to use links that exceed their tolerance for traffic stress, and that do not involve an undue level of detour. The objective of this study is to develop measures of low-stress connectivity that can be used to evaluate and guide bicycle network planning. We propose a set of criteria by which road segments can be classified into four levels of traffic stress (LTS). LTS 1 is suitable for children; LTS 2, based on Dutch bikeway design criteria, represents the traffic stress that most adults will tolerate; LTS 3 and 4 represent greater levels of stress. As a case study, every street in San Jose, California, was classified by LTS. Maps in which only bicycle-friendly links are displayed reveal a city divided into islands within which low-stress bicycling is possible, but separated from one another by barriers that can be crossed only by using high-stress links. Two points in the network are said to be connected at a given level of traffic stress if the subnetwork of links that do not exceed the specified level of stress connects them with a path whose length does not exceed a detour criterion (25% longer than the most direct path). For the network as a whole, we demonstrate two measures of connectivity that can be applied for a given level of traffic stress. One is “percent trips connected,” defined as the fraction of trips in the regional trip table that can be made without exceeding a specified level of stress and without excessive detour. This study used the home-to-work trip table, though in principle any trip table, including all trips, could be used. The second is “percent nodes connected,” a cruder measure that does not require a regional trip table, but measures the fraction of nodes in the street network (mostly street intersections) that are connected to each other. Because traffic analysis zones (TAZs) are too coarse a geographic unit for evaluating connectivity by bicycle, we also demonstrate a method of disaggregating the trip table from the TAZ level to census blocks. For any given TAZ, origins in the home-to-work trip table are allocated in proportion to population, while destinations are allocated based on land-use data. In the base case, the fraction of work trips up to six miles long that are connected at LTS 2 is 4.7%, providing a plausible explanation for the city’s low bicycling share. We show that this figure would almost triple if a proposed slate of improvements, totaling 32 miles in length but with strategically placed segments that provide low-stress connectivity across barriers, were implemented

    Education For Thinking

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    Rediscovery of a lost semi-aquatic Leaf Beetle in the Hula Valley, Israel (Coleoptera, Chrysomelidae, Donaciinae)

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    : Between 1951-1958, most of the Hula Lake and its surrounding swamps in the Upper Jordan River (Rift) Valley of Israel were drained with the supposed purposes to eliminate malaria and to reclaim land for agriculture; both reasons later proved to be unnecessary decisions. With the paucity of biological knowledge of the Hula region, especially its aquatic invertebrates, accurate assessment of the environmental damage from this drainage is still being realized. Based on natural history museum collection specimen records, the pre-drainage presence of some aquatic insect species has been verified. Among these was Donaciabicolora, a member of a semi-aquatic subfamily (Donaciinae) of Leaf Beetles (Chrysomelidae) and whose Israeli populations were thought to have gone extinct because of the drainage of the Hula and other locations. Recently this species was rediscovered in two populations. However, the molecular identification of two of these recently collected specimens from one population revealed that the identity of this species is actually Donaciasimplex. In this work, the re-discovery of this species is detailed, and its conservation importance discussed

    Discovery and Designation of Type Specimens of Chrysomelidae (Coleoptera) From Argentina Described by E. von Harold in 1875

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    Type specimens of 14 species of Chrysomelidae from Cordova, Argentina. collected by W. M. Davis and described by E. von Harold in 1875, were discovered in the collections of the Museum of Comparative Zoology (Harvard University). A few specimens from some other museums such as the Museum für Naturkunde der Humboldt-Universität (Berlin), The Natural History Museum (London), Institut Royal des Sciences Naturelles de Belgique (Brussels), Museo Nacional de Hungaria (Budapest) are also apparently from the original series. Lectotypes and paralectotypes are designated for all species

    Self-Organizing Signals: A Better Framework for Transit Signal Priority

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    Actuated traffic signal control logic has many advantages because of its responsiveness to traffic demands, short cycles, effective use of capacity leading to and recovering from oversaturation, and amenability to aggressive transit priority. Its main drawback has been its inability to provide good progression along arterials. However, the traditional way of providing progression along arterials, coordinated-actuated control with a common, fixed cycle length, has many drawbacks stemming from its long cycle lengths, inflexibility in recovering from priority interruptions, and ineffective use of capacity during periods of oversaturation. This research explores a new paradigm for traffic signal control, “self-organizing signals,” based on local actuated control but with some additional rules that create coordination mechanisms. The primary new rules proposed are for secondary extensions, in which the green may be held to serve an imminently arriving platoon, and dynamic coordination, in which small groups of closely spaced signals communicate with one another to cycle synchronously with the group’s critical intersection. Simulation tests in VISSIM performed on arterial corridors in Massachusetts and Arizona show overall delay reductions of up to 14% compared to an optimized coordinated-actuated scheme where there is no transit priority, and more than 30% in scenarios with temporary oversaturation. Tests also show that with self-organizing control, transit signal priority can be more effective than with coordinated-actuated control, reducing transit delay by about 60%, or 12 to 14 s per intersection with little impact on traffic delay.https://pdxscholar.library.pdx.edu/trec_seminar/1054/thumbnail.jp

    Checklist of the Alticinae of Central America, including Mexico (Coleoptera: Chrysomelidae)

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    This is a comprehensive list of all recorded species (866), including 11 subspecies, and genera (113) of Alticinae from Mexico to Panama, but also includes complete distributional data (with references) for each species. It includes all generic and specific synonymies published since the 1939-1940 Coleopterorum Catalogus. There are three new combinations and a new synonym. This checklist basically follows and, for the first time comprehensively synthesizes, the taxon arrangement of the late Jan Bechyne
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