3,520 research outputs found

    Comparing Fixed-amount and Progressive-amount DRO Schedules for Tic Suppression in Youth with Chronic Tic Disorders

    Get PDF
    Chronic tic disorders (CTDs) involve motor and/or vocal tics that often cause substantial distress and impairment. Differential reinforcement of other behavior (DRO) schedules of reinforcement produce robust, but incomplete, reductions in tic frequency in youth with CTDs; however, a more robust reduction may be needed to affect durable clinical change. Standard, fixed‐amount DRO schedules have not commonly yielded such reductions, so we evaluated a novel, progressive‐amount DRO schedule, based on its ability to facilitate sustained abstinence from functionally similar behaviors. Five youth with CTDs were exposed to periods of baseline, fixed‐amount DRO (DRO‐F), and progressive‐amount DRO (DRO‐P). Both DRO schedules produced decreases in tic rate and increases in intertic interval duration, but no systematic differences were seen between the two schedules on any dimension of tic occurrence. The DRO‐F schedule was generally preferred to the DRO‐P schedule. Possible procedural improvements and other future directions are discussed

    Estimating long-term volatility parameters for market-consistent models

    Get PDF
    Contemporary actuarial and accounting practices (APN 110 in the South African context) require the use of market-consistent models for the valuation of embedded investment derivatives. These models have to be calibrated with accurate and up-to-date market data. Arguably, the most important variable in the valuation of embedded equity derivatives is implied volatility. However, accurate long-term volatility estimation is difficult because of a general lack of tradable, liquid medium- and long-term derivative instruments, be they exchange-traded or over the counter. In South Africa, given the relatively short-term nature of the local derivatives market, this is of particular concern. This paper attempts to address this concern by: — providing a comprehensive, critical evaluation of the long-term volatility models most commonly used in practice, encompassing simple historical volatility estimation and econometric, deterministic and stochastic volatility models; and — introducing several fairly recent nonparametric alternative methods for estimating long-term volatility, namely break-even volatility and canonical option valuation. The authors apply these various models and methodologies to South African market data, thus providing practical, long-term volatility estimates under each modelling framework whilst accounting for real-world difficulties and constraints. In so doing, they identify those models and methodologies they consider to be most suited to long-term volatility estimation and propose best estimation practices within each identified area. Thus, while application is restricted to the South African market, the general discussion, as well as the suggestion of best practice, in each of the evaluated modelling areas remains relevant for all long-term volatility estimation

    Remarkably robust and correlated coherence and antiferromagnetism in (Ce1x_{1-x}Lax_x)Cu2_2Ge2_2

    Get PDF
    We present magnetic susceptibility, resistivity, specific heat, and thermoelectric power measurements on (Ce1x_{1-x}Lax_x)Cu2_2Ge2_2 single crystals (0 x\leq x\leq 1). With La substitution, the antiferromagnetic temperature TNT_N is suppressed in an almost linear fashion and moves below 0.36 K, the base temperature of our measurements for x>x> 0.8. Surprisingly, in addition to robust antiferromagnetism, the system also shows low temperature coherent scattering below TcohT_{coh} up to \sim 0.9 of La, indicating a small percolation limit \sim 9%\% of Ce that separates a coherent regime from a single-ion Kondo impurity regime. TcohT_{coh} as a function of magnetic field was found to have different behavior for xx 0.9. Remarkably, (Tcoh)2(T_{coh})^2 at HH = 0 was found to be linearly proportional to TNT_N. The jump in the magnetic specific heat δCm\delta C_{m} at TNT_N as a function of TK/TNT_K/T_N for (Ce1x_{1-x}Lax_x)Cu2_2Ge2_2 follows the theoretical prediction based on the molecular field calculation for the SS = 1/2 resonant level model

    Interaction of temperature and CO2 enrichment on soybean : Photosynthesis and seed yield

    Get PDF
    Seed yield and photosynthetic responses of soybean (Gtycine mnx L. Met. ,Ransom') were studied in growth chambers at day/night temperatures of 18/12,22/16, and 26/20'C and atmospheric CO, concentrations of 350, 6i5 and 1000 pL L-1. No seeds were produced at 18/12°C within any of the CO2 concentrations. Numbers of pods and seeds increased with increasing temperature and CO2 levels. Carbon dioxide enrichment increased seed yield of soybean grown at moderately cool temperatures. This increase was associated with an increase in net photosynthetic rate. Leaf photosynthesis in response to CO2 enrichment increased more at 22/16°C than at 26/20°C. Increases in, temperature and CO2 levels enhanced total growth of plants but hastened senescence of leaves. The extended photosynthetic capacity at cool temperatures did not result in allocating more dry matter to developing pods. CO2 enrichment at 26/20°C resulted in greater seed yield increases than CO2 enrichment at lower temperatures

    The development of British civil affairs and its employment in the British sector of allied military operations during the Battle of Normandy, June to August 1944

    Get PDF
    Civil Affairs and its more robust sibling, Military Government, were military organisations designed to ensure that basic civil order and welfare were maintained in those allied and enemy states encountered on operations during the Second World War. In so doing, they enabled formation commanders to focus on defeating enemy forces without being distracted by possible civilian problems. Using the battle of Normandy as a case study, this research assesses the utility of Civil Affairs in supporting military needs during operations. This contrasts with previous studies that concentrate on aspects of social and diplomatic history. If the need for Civil Affairs was generally axiomatic, there was much debate as to the extent and method of delivery required. Civil Affairs quickly recognised that in dealing with direct problems such as “disorganisation, disease and unrest” it was necessary for seemingly indirect aspects of civilian life to be maintained. Various forms of bureaucratic friction resulted and several Civil Affairs approaches were used, before the model for the North West Europe campaign was agreed. Nevertheless, the organisation employed in Normandy was arguably the most extensive and best prepared of the war. However, it also had to deal with many different civilian problems and in trying military circumstances. Consequently, the battle is fertile ground for the examination of the extent and nature of the organisation’s operational utility. Using primary and secondary sources, this paper argues that Civil Affairs was militarily both useful and necessary. Furthermore, it was able to provide wider diplomatic and political benefits as well as serving core military needs. The research concludes by acknowledging that whilst mistakes were made, the various improvements made to Civil Affairs in preparation for, together with the lessons learnt during, Normandy stood the organisation in good stead for the significantly larger problems encountered later in the war.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Public welfare or sectarianism: A new challenge for planning

    Get PDF
    Introduction Theoretical background Methodology The Haredi in Jerusalem Kiryat-Ha'Yovel “Terrain of interests” between Haredi and secular in Kiryat-Ha'Yovel Organisation in housing Potential for influencing planning decisions Conclusions: failure of liberalism or all-you-can-grab planning? Full Article Figures & data References Citations Metrics Reprints & Permissions PDF Abstract This article examines the weaknesses of liberal planning institutions when dealing with organised group action. The case under review, the Kiryat-Ha'Yovel neighbourhood in Jerusalem, was considered as secular for many years. In 2000 the neighbourhood became attractive to the nearby Haredi (ultra-orthodox Jews) group of the “Kol-Torah’ community. Differences in lifestyle led to a collision between the group of “Kol-Torah”, who began “Haredification” processes to change the character of the area to be suitable to Haredim, and the veteran population, who tried to prevent it. Identifying the main engines of organised neighbourhood change and evaluating the difficulties of liberalism dealing with non-autonomous individuals in the housing market sheds light on similar processes occurring in other city centres with diverse population groups

    Resuscitation and quantification of stressed Escherichia coli K12 NCTC8797 in water samples

    Get PDF
    The aim of this study was to investigate the impact on numbers of using different media for the enumeration of Escherichia coli subjected to stress, and to evaluate the use of different resuscitation methods on bacterial numbers. E. coli was subjected to heat stress by exposure to 55 °C for 1 h or to light-induced oxidative stress by exposure to artificial light for up to 8 h in the presence of methylene blue. In both cases, the bacterial counts on selective media were below the limits of detection whereas on non-selective media colonies were still produced. After resuscitation in non-selective media, using a multi-well MPN resuscitation method or resuscitation on membrane filters, the bacterial counts on selective media matched those on non-selective media. Heat and light stress can affect the ability of E. coli to grow on selective media essential for the enumeration as indicator bacteria. A resuscitation method is essential for the recovery of these stressed bacteria in order to avoid underestimation of indicator bacteria numbers in water. There was no difference in resuscitation efficiency using the membrane filter and multi-well MPN methods. This study emphasises the need to use a resuscitation method if the numbers of indicator bacteria in water samples are not to be underestimated. False-negative results in the analysis of drinking water or natural bathing waters could have profound health effects
    corecore