3,196 research outputs found

    Evaluating Pooled Evidence from the Reemployment Bonus Experiments

    Get PDF
    Social experiments conducted in Pennsylvania and Washington tested the effect of offering Unemployment Insurance (UI) claimants a cash bonus for rapid reemployment. This paper combines data from the two experiments and uses a consistent framework to evaluate the experiments and determine with greater certainty the extent to which a reemployment bonus can affect economic outcomes. Bonus offers in each of the experiments generated statistically significant but relatively modest reductions in UI receipt. Since the estimated impacts on UI receipt were modest, the reemployment bonuses did not generate the UI savings necessary to pay for administering and paying the bonuses. Hence, contrary to earlier findings from a bonus experiment conducted in Illinois, findings from the Pennsylvania and Washington experiments strongly suggest that a reemployment bonus is not a cost-effective method of speeding the reemployment of UI claimants.unemployment, insurance, bonus, experiments, O'Leary, Decker

    Homeostasis, failure of homeostasis and degenerate ion channel regulation

    Get PDF
    Most neurons express a wide variety of ion channels with diverse properties, providing a rich toolbox for tuning neural function. Coexpressed channel types are often degenerate: they share overlapping roles in shaping electrophysiological properties. This can allow one set of channels to compensate the role of others, thus making nervous systems robust to perturbations such as channel deletions and mutations, expression noise or environmental disturbances. In tandem, activity-dependent homeostatic mechanisms can actively regulate channel expression to counteract perturbations by sensing changes in physiological activity. However, recent work shows that in spite of degeneracy and homeostatic regulation, the compensatory outcome of a perturbation can be unpredictable. Sometimes a single mutation in an ion channel gene can be catastrophic, while in other contexts a similar loss of function might be compensated. Compensation sometimes fails even when there may be many potential ways to compensate using available channels. Theoretical models show how homeostatic mechanisms that regulate degenerate conductances can fail and even cause pathologies through aberrant compensation

    Ultrasonic wave propagation in cylindrical vessels and implications for ultrasonic reactor design

    Get PDF
    Reactors in which processes are enhanced by ultrasound are hampered by the lack of a theoretical framework on their design. Simulation results of ultrasonic wave propagation in a cylindrical geometry are presented in this work, which are then used to develop guidelines for the design of ultrasonic reactors. These guidelines are used to design a new type of reactor with a novel geometry, operating at a frequency of 27kHz, 39kHz and 82kHz. This reactor is characterized using Weissler's reaction dosimetr

    Cost-Effectiveness of Targeted Reemployment Bonuses

    Get PDF
    Targeting reemployment bonus offers to unemployment insurance (UI) claimants identified as most likely to exhaust benefits is estimated to reduce benefit payments. While earlier research indicated that non-targeted reemployment bonus offers would not be good public policy, in this paper we show that targeting bonus offers with profiling models similar to those in state Worker Profiling and Reemployment Services (WPRS) systems can improve their cost effectiveness. Since estimated average benefit payments do not steadily decline as the eligibility screen is gradually tightened, we find that narrow targeting is not optimal. The best candidate to emerge for a targeted reemployment bonus is a low bonus amount with a long qualification period, targeted to the half of profiled claimants most likely to exhaust their UI benefit entitlement.reemployment, bonus, UI, personal, accounts, PRA, unemployment, insurance, Upjohn, Institute, O'Leary, Decker, Wandner

    On the local integrability and boundedness of solutions to quasilinear parabolic systems

    Get PDF
    We introduce a structure condition of parabolic type, which allows for the generalization to quasilinear parabolic systems of the known results of integrability, and boundedness of local solutions to singular and degenerate quasilinear parabolic equations

    Analysis of ultrasonic transducers with fractal architecture

    Get PDF
    Ultrasonic transducers composed of a periodic piezoelectric composite are generally accepted as the design of choice in many applications. Their architecture is normally very regular and this is due to manufacturing constraints rather than performance optimisation. Many of these manufacturing restrictions no longer hold due to new production methods such as computer controlled, laser cutting, and so there is now freedom to investigate new types of geometry. In this paper, the plane wave expansion model is utilised to investigate the behaviour of a transducer with a self-similar architecture. The Cantor set is utilised to design a 2-2 conguration, and a 1-3 conguration is investigated with a Sierpinski Carpet geometry

    Cell types, network homeostasis, and pathological compensation from a biologically plausible ion channel expression model.

    Get PDF
    How do neurons develop, control, and maintain their electrical signaling properties in spite of ongoing protein turnover and perturbations to activity? From generic assumptions about the molecular biology underlying channel expression, we derive a simple model and show how it encodes an "activity set point" in single neurons. The model generates diverse self-regulating cell types and relates correlations in conductance expression observed in vivo to underlying channel expression rates. Synaptic as well as intrinsic conductances can be regulated to make a self-assembling central pattern generator network; thus, network-level homeostasis can emerge from cell-autonomous regulation rules. Finally, we demonstrate that the outcome of homeostatic regulation depends on the complement of ion channels expressed in cells: in some cases, loss of specific ion channels can be compensated; in others, the homeostatic mechanism itself causes pathological loss of function.Charles A. King TrustThis is the final version of the article. It first appeared from Cell Press (Elsevier) via http://dx.doi.org/10.1016/j.neuron.2014.04.002

    Correlations in ion channel expression emerge from homeostatic tuning rules.

    Get PDF
    Experimental observations reveal that the expression levels of different ion channels vary across neurons of a defined type, even when these neurons exhibit stereotyped electrical properties. However, there are robust correlations between different ion channel expression levels, although the mechanisms that determine these correlations are unknown. Using generic model neurons, we show that correlated conductance expression can emerge from simple homeostatic control mechanisms that couple expression rates of individual conductances to cellular readouts of activity. The correlations depend on the relative rates of expression of different conductances. Thus, variability is consistent with homeostatic regulation and the structure of this variability reveals quantitative relations between regulation dynamics of different conductances. Furthermore, we show that homeostatic regulation is remarkably insensitive to the details that couple the regulation of a given conductance to overall neuronal activity because of degeneracy in the function of multiple conductances and can be robust to "antihomeostatic" regulation of a subset of conductances expressed in a cell.Swartz FoundationThis is the final version of the article. It first appeared from National Academy of Sciences via http://dx.doi.org/10.1073/pnas.1309966110

    Artificial Reefs Feasibility Study

    Get PDF
    The Marine Institute commissioned this study to review the current status of artificial reefs world-wide with a view to determining the feasibility of the development of a sea angling initiative based on the deployment and exploitation of artificial reefs. The study, conducted by the Coastal Resources Centre, National University of Ireland, Cork, includes a review of the current status of artificial reefs globally with a focus on site selection, reef design, construction material and reef use. The Beara Tourism Development Association has expressed an interest in developing a sustainable sea angling initiative based on the construction of a series of artificial reef sites. In response to this interest, the Beara Peninsula was used as a case study area for the purpose of determining feasible artificial reef site locations. Consultations with relevant regulatory bodies, local tourism development groups and the sea angling sector in the Beara Peninsula were an essential element of this study. The use and benefits of artificial reefs have been widely accepted with both ongoing research and national development programmes in place in over forty countries worldwide. In Japan for example, national programmes have been in operation for over twenty years. The Japanese have been at the forefront of reef design, construction and deployment since their inception. However, little research has ever been undertaken on artificial reefs in Ireland, to date one application for the creation of an artificial reef has been submitted to the Department of the Marine & Natural Resources.Funder: Marine Institut

    Geomorphology and late Holocene accretion history of Adele Reef: a northwest Australian mid-shelf platform reef

    Get PDF
    The mid-shelf reefs of the Kimberley Bioregion are one of Australia’s more remote tropical reef provinces and such have received little attention from reef researchers. This study describes the geomorphology and late Holocene accretion history of Adele Reef, a mid-shelf platform reef, through remote sensing of contemporary reef habitats, shallow seismic profiling, shallow percussion coring and radiocarbon dating. Seismic profiling indicates that the Holocene reef sequence is 25 to 35 m thick and overlies at least three earlier stages of reef build-up, interpreted as deposited during marine isotope stages 5, 7 and 9 respectively. The cored shallow subsurface facies of Adele Reef are predominantly detrital, comprising small coral colonies and fragments in a sandy matrix. Reef cores indicate a ‘catch-up’ growth pattern, with the reef flat being approximately 5–10 m deep when sea level stabilised at its present elevation 6,500 years BP. The reef flat is rimmed by a broad low-relief reef crest only 10–20 cm high, characterised by anastomosing ridges of rhodoliths and coralliths. The depth of the Holocene/last interglacial contact (25–30 m) suggests a subsidence rate of 0.2 mm/year for Adele Reef since the last interglacial. This value, incorporated with subsidence rates from Cockatoo Island (inshore) and Scott Reefs (offshore), provides the first quantitative estimate of hinge subsidence for the Kimberley coast and adjacent shelf, with progressively greater subsidence across the shelf
    corecore