A NEW MEMBRACID FROM WEST JAVA.

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The probing behaviour of nymphs of Vanduzeea arquata and Enchenopa binotata (Homoptera: Membracidae) on host and non-host plants

1. Nymphs of Vanduzeea arquata Say have been found to be more host-specific in nature and to show a higher degree of selectivity in host discrimination experiments than nymphs of Enchenopa binotata (Say), It was hypothesized that this differential selectivity would be reflected in the probing behaviour of individuals placed on twigs of host and non-host plants. Probing behaviour was examined by direct observation of nymphs and by sectioning and staining the probed plant tissues. 2. All nymphs probed readily and for extended periods on both host and non-host twigs. E.binotuta nymphs showed no consistent differences in probing behaviour on hosts versus non-hosts, but V.atquuta nymphs were more likely to withdraw their stylets within 60 s when on non-host twigs and produced honeydew only when on their host species. V.urquatu nymphs reached the phloem sieve elements only when on host twigs and broke many cells in peripheral plant tissue layers while probing. E.binotata nymphs broke few cells and often reached the phloem of non-host as well as host plants. 3. Nymphs of V.arquata always reject non-host plants, apparently in the course of probing and prior to encountering the phloem sap. Chemical compounds released from ruptured parenchyma cells may act as probing stimulants or inhibitors. E.binotura nymphs often feed on non-host plants in a non-choice situation; their preferential settling on host twigs in discrimination experiments may reflect a tendency to abandon non-host twigs more readily than host twigs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72791/1/j.1365-2311.1984.tb00840.x.pd

Algorithms to automatically quantify the geometric similarity of anatomical surfaces

We describe new approaches for distances between pairs of 2-dimensional surfaces (embedded in 3-dimensional space) that use local structures and global information contained in inter-structure geometric relationships. We present algorithms to automatically determine these distances as well as geometric correspondences. This is motivated by the aspiration of students of natural science to understand the continuity of form that unites the diversity of life. At present, scientists using physical traits to study evolutionary relationships among living and extinct animals analyze data extracted from carefully defined anatomical correspondence points (landmarks). Identifying and recording these landmarks is time consuming and can be done accurately only by trained morphologists. This renders these studies inaccessible to non-morphologists, and causes phenomics to lag behind genomics in elucidating evolutionary patterns. Unlike other algorithms presented for morphological correspondences our approach does not require any preliminary marking of special features or landmarks by the user. It also differs from other seminal work in computational geometry in that our algorithms are polynomial in nature and thus faster, making pairwise comparisons feasible for significantly larger numbers of digitized surfaces. We illustrate our approach using three datasets representing teeth and different bones of primates and humans, and show that it leads to highly accurate results.Comment: Changes with respect to v1, v2: an Erratum was added, correcting the references for one of the three datasets. Note that the datasets and code for this paper can be obtained from the Data Conservancy (see Download column on v1, v2

Molecular Beams

Contains reports on five research projects.Lincoln Laboratory (Purchase Order DDL B-00306)United States Air Force (Contract AF19(604)-7400)United States NavyUnited States Arm

Temperature-sensitive Tien Shan tree ring chronologies show multi-centennial growth trends

Two millennia-length juniper ring width chronologies, processed to preserve multi-centennial growth trends, are presented for the Alai Range of the western Tien Shan in Kirghizia. The chronologies average the information from seven near-timberline sampling sites, and likely reflect summer temperature variation. For comparison, chronologies are also built using standard dendrochronological techniques. We briefly discuss some qualities of these "inter-decadal” records, and show the low frequency components removed by the standardization process include a long-term negative trend in the first half of the last millennium and a long-term positive trend since about AD 1800. The multi-centennial scale Alai Range chronologies, where these trends are retained, are both systematically biased (but in an opposite sense) in their low frequency domains. Nevertheless, they represent the best constraints and estimates of long-term summer temperature variation, and reflect the Medieval Warm Period, the Little Ice Age, and a period of warming since about the middle of the nineteenth centur

RESOLUTION‐RETRIEVING SOURCE‐EFFECT COMPENSATION IN HOLOGRAPHY WITH EXTENDED SOURCES

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69575/2/APPLAB-7-6-178-1.pd

The thermodynamic evolution of the cosmological event horizon

By manipulating the integral expression for the proper radius $R_e$ of the cosmological event horizon (CEH) in a Friedmann-Robertson-Walker (FRW) universe, we obtain an analytical expression for the change \dd R_e in response to a uniform fluctuation \dd\rho in the average cosmic background density $\rho$. We stipulate that the fluctuation arises within a vanishing interval of proper time, during which the CEH is approximately stationary, and evolves subsequently such that \dd\rho/\rho is constant. The respective variations 2\pi R_e \dd R_e and \dd E_e in the horizon entropy $S_e$ and enclosed energy $E_e$ should be therefore related through the cosmological Clausius relation. In that manner we find that the temperature $T_e$ of the CEH at an arbitrary time in a flat FRW universe is $E_e/S_e$, which recovers asymptotically the usual static de Sitter temperature. Furthermore, it is proven that during radiation-dominance and in late times the CEH conforms to the fully dynamical First Law T_e \drv S_e = P\drv V_e - \drv E_e, where $V_e$ is the enclosed volume and $P$ is the average cosmic pressure.Comment: 6 page

An open framework for risk management

Risk assessment methodologies are ready to enter their third generation. In this next generation, assessment will be based on a whole system understanding of the system to be assessed. To realize this vision of risk management, the authors have begun development of an extensible software tool kit. This tool kit breaks with the traditional approach to assessment by having the analyst spend the majority of the assessment time building an explicit model that documents in a single framework the various facets of the system, such as the system`s behavior, structure, and history. Given this explicit model of the system, a computer is able to automatically produce a standard assessment products, such as fault trees and event trees. This brings with it a number of advantages relative to current risk management tools. Among these are a greater sense of completeness and correctness in assessment results and the ability to preserve and later employ lessons learned