184 research outputs found

    Viscoelastic and Dynamic Properties of Soft Liners and Tissue Conditioners

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    The creep compliance and dynamic modulus of two tissue conditioners and five soft liners were determined after storage in water at 37 C. Under static conditions the tissue conditioners functioned like viscous liquids, whereas the soft liners were more elastic. In general, linear viscoelasticity was not observed. Under dynamic conditions, the materials were stiffer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67015/2/10.1177_00220345790580080601.pd

    IN THIS ISSUE: What Are Characteristics of Significant Research?

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67303/2/10.1177_108056999505800214.pd

    OBDD-Based Representation of Interval Graphs

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    A graph G=(V,E)G = (V,E) can be described by the characteristic function of the edge set χE\chi_E which maps a pair of binary encoded nodes to 1 iff the nodes are adjacent. Using \emph{Ordered Binary Decision Diagrams} (OBDDs) to store χE\chi_E can lead to a (hopefully) compact representation. Given the OBDD as an input, symbolic/implicit OBDD-based graph algorithms can solve optimization problems by mainly using functional operations, e.g. quantification or binary synthesis. While the OBDD representation size can not be small in general, it can be provable small for special graph classes and then also lead to fast algorithms. In this paper, we show that the OBDD size of unit interval graphs is O( V /log V )O(\ | V \ | /\log \ | V \ |) and the OBDD size of interval graphs is $O(\ | V \ | \log \ | V \ |)whichbothimproveaknownresultfromNunkesserandWoelfel(2009).Furthermore,wecanshowthatusingourvariableorderandnodelabelingforintervalgraphstheworstcaseOBDDsizeis which both improve a known result from Nunkesser and Woelfel (2009). Furthermore, we can show that using our variable order and node labeling for interval graphs the worst-case OBDD size is \Omega(\ | V \ | \log \ | V \ |).Weusethestructureoftheadjacencymatricestoprovethesebounds.Thismethodmaybeofindependentinterestandcanbeappliedtoothergraphclasses.Wealsodevelopamaximummatchingalgorithmonunitintervalgraphsusing. We use the structure of the adjacency matrices to prove these bounds. This method may be of independent interest and can be applied to other graph classes. We also develop a maximum matching algorithm on unit interval graphs using O(\log \ | V \ |)operationsandacoloringalgorithmforunitandgeneralintervalsgraphsusing operations and a coloring algorithm for unit and general intervals graphs using O(\log^2 \ | V \ |)$ operations and evaluate the algorithms empirically.Comment: 29 pages, accepted for 39th International Workshop on Graph-Theoretic Concepts 201

    The synaptic vesicle protein CSP alpha prevents presynaptic degeneration

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    Cysteine string protein α (CSPα)—an abundant synaptic vesicle protein that contains a DNA-J domain characteristic of Hsp40 chaperones—is thought to regulate Ca2+ channels and/or synaptic vesicle exocytosis. We now show that, in young mice, deletion of CSPα does not impair survival and causes no significant changes in presynaptic Ca2+ currents or synaptic vesicle exocytosis as measured in the Calyx of Held synapse. At 2–4 weeks of age, however, CSPα-deficient mice develop a progressive, fatal sensorimotor disorder. The neuromuscular junctions and Calyx synapses of CSPα-deficient mice exhibit increasing neurodegenerative changes, synaptic transmission becomes severely impaired, and the mutant mice die at ∼2 months of age. Our data suggest that CSPα is not essential for the normal operation of Ca2+ channels or exocytosis but acts as a presynaptic chaperone that maintains continued synaptic function, raising the possibility that enhanced CSPα function could attenuate neurodegenerative diseases

    Microphytobenthos of Arctic Kongsfjorden (Svalbard, Norway): biomass and potential primary production along the shore line

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    During summer 2007, Arctic microphytobenthic potential primary production was measured at several stations around the coastline of Kongsfjorden (Svalbard, Norway) at ?5 m water depth and at two stations at five different water depths (5, 10, 15, 20, 30 m). Oxygen planar optode sensor spots were used ex situ to determine oxygen exchange in the overlying water of intact sediment cores under controlled light (ca. 100 ?mol photons m?2 s?1) and temperature (2–4°C) conditions. Patches of microalgae (mainly diatoms) covering sandy sediments at water depths down to 30 m showed high biomass of up to 317 mg chl a m?2. In spite of increasing water depth, no significant trend in “photoautotrophic active biomass” (chl a, ratio living/dead cells, cell sizes) and, thus, in primary production was measured at both stations. All sites from ?5 to 30 m water depth exhibited variable rates of net production from ?19 to +40 mg O2 m?2 h?1 (?168 to +360 mg C m?2 day?1) and gross production of about 2–62 mg O2 m?2 h?1 (17–554 mg C m?2 day?1), which is comparable to other polar as well as temperate regions. No relation between photoautotrophic biomass and gross/net production values was found. Microphytobenthos demonstrated significant rates of primary production that is comparable to pelagic production of Kongsfjorden and, hence, emphasised the importance as C source for the zoobenthos

    The Role of Individual Variables, Organizational Variables and Moral Intensity Dimensions in Libyan Management Accountants’ Ethical Decision Making

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    This study investigates the association of a broad set of variables with the ethical decision making of management accountants in Libya. Adopting a cross-sectional methodology, a questionnaire including four different ethical scenarios was used to gather data from 229 participants. For each scenario, ethical decision making was examined in terms of the recognition, judgment and intention stages of Rest’s model. A significant relationship was found between ethical recognition and ethical judgment and also between ethical judgment and ethical intention, but ethical recognition did not significantly predict ethical intention—thus providing support for Rest’s model. Organizational variables, age and educational level yielded few significant results. The lack of significance for codes of ethics might reflect their relative lack of development in Libya, in which case Libyan companies should pay attention to their content and how they are supported, especially in the light of the under-development of the accounting profession in Libya. Few significant results were also found for gender, but where they were found, males showed more ethical characteristics than females. This unusual result reinforces the dangers of gender stereotyping in business. Personal moral philosophy and moral intensity dimensions were generally found to be significant predictors of the three stages of ethical decision making studied. One implication of this is to give more attention to ethics in accounting education, making the connections between accounting practice and (in Libya) Islam. Overall, this study not only adds to the available empirical evidence on factors affecting ethical decision making, notably examining three stages of Rest’s model, but also offers rare insights into the ethical views of practising management accountants and provides a benchmark for future studies of ethical decision making in Muslim majority countries and other parts of the developing world

    Ecological ReGional Ocean Model with vertically resolved sediments (ERGOM SED 1.0): coupling benthic and pelagic biogeochemistry of the south-western Baltic Sea

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    Sediments play an important role in organic matter mineralisation and nutrient recycling, especially in shallow marine systems. Marine ecosystem models, however, often only include a coarse representation of processes beneath the sea floor. While these parameterisations may give a reasonable description of the present ecosystem state, they lack predictive capacity for possible future changes, which can only be obtained from mechanistic modelling. This paper describes an integrated benthic–pelagic ecosystem model developed for the German Exclusive Economic Zone (EEZ) in the western Baltic Sea. The model is a hybrid of two existing models: the pelagic part of the marine ecosystem model ERGOM and an early diagenetic model by Reed et al. (2011). The latter one was extended to include the carbon cycle, a determination of precipitation and dissolution reactions which accounts for salinity differences, an explicit description of the adsorption of clay minerals, and an alternative pyrite formation pathway. We present a one-dimensional application of the model to seven sites with different sediment types. The model was calibrated with observed pore water profiles and validated with results of sediment composition, bioturbation rates and bentho-pelagic fluxes gathered by in situ incubations of sediments (benthic chambers). The model results generally give a reasonable fit to the observations, even if some deviations are observed, e.g. an overestimation of sulfide concentrations in the sandy sediments. We therefore consider it a good first step towards a three-dimensional representation of sedimentary processes in coupled pelagic–benthic ecosystem models of the Baltic Sea.</p

    Impact Factor: outdated artefact or stepping-stone to journal certification?

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    A review of Garfield's journal impact factor and its specific implementation as the Thomson Reuters Impact Factor reveals several weaknesses in this commonly-used indicator of journal standing. Key limitations include the mismatch between citing and cited documents, the deceptive display of three decimals that belies the real precision, and the absence of confidence intervals. These are minor issues that are easily amended and should be corrected, but more substantive improvements are needed. There are indications that the scientific community seeks and needs better certification of journal procedures to improve the quality of published science. Comprehensive certification of editorial and review procedures could help ensure adequate procedures to detect duplicate and fraudulent submissions.Comment: 25 pages, 12 figures, 6 table

    Breaking Traditions:An Isotopic Study on the Changing Funerary Practices in the Dutch Iron Age (800-12 bc)

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    Urnfields in the Dutch river area were replaced by cemeteries with a mixture of cremation and inhumation graves around the sixth century bc. This study provides the first biogeochemical evidence that the Iron Age communities were heterogeneous in terms of geological origins. The high percentage of non-locally born individuals (~48%) supports the hypothesis that the change in burial practice was the result of the influx of foreign people, who were being allowed to keep their own burial customs, whereas some of the local inhabitants adapted the burial rites of foreign cultures, leading to a heterogeneous burial rite for some centuries
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