229 research outputs found
A Test for the Presence of Central Bank Intervention in the Foreign Exchange Market With an Application to the Bank of Canada
We propose a general non-linear simultaneous equations framework for the econometric analysis of models of intervention in foreign exchange markets by central banks in response to deviations of exchange rates from target levels. We consider the instrumental variables estimation of possibly non-linear response functions and tests of intervention when the functional form may be non-linear, asymmetric, and may contain unknown shape parameters. The methodology applies techniques developed for testing in the presence of nuisance parameters unidentified under a null hypothesis to a nonlinear simultaneous equations model. We report the results of an empirical analysis of activity of the Bank of Canada, for the period from 1953-2006, with regard to the Canada-U.S. exchange rate, with changes in foreign reserves proxying for intervention activity. Nous proposons un cadre de rĂ©fĂ©rence gĂ©nĂ©ral pour les Ă©quations non-linĂ©aires simultanĂ©es sâappliquant Ă lâanalyse Ă©conomĂ©trique de modĂšles dâintervention des banques centrales dans les marchĂ©s des devises Ă©trangĂšres, en rĂ©ponse aux Ă©carts des taux de change par rapport aux niveaux cibles. Nous prenons en considĂ©ration lâestimation des variables instrumentales liĂ©es aux fonctions de rĂ©ponses possiblement non-linĂ©aires et aux tests en matiĂšre dâinterventions lorsque la forme fonctionnelle peut ĂȘtre non linĂ©aire, asymĂ©trique et lorsquâelle peut contenir des paramĂštres de forme inconnue. La mĂ©thodologie applique, Ă un modĂšle Ă Ă©quations simultanĂ©es non linĂ©aires, des techniques Ă©laborĂ©es pour effectuer des tests en prĂ©sence de paramĂštres de nuisance non identifiĂ©s sous une hypothĂšse nulle. Nous prĂ©sentons les rĂ©sultats dâune analyse empirique des activitĂ©s de la Banque du Canada, durant la pĂ©riode de 1953-2006, relativement au taux de change Canada-Ă.-U., les variations des rĂ©serves Ă©trangĂšres permettant les activitĂ©s dâintervention.unidentified nuisance parameter, nonlinear simultaneous equations, foreign exchange reserves, policy reaction functions, paramĂštre de nuisance non identifiĂ©, Ă©quations simultanĂ©es non linĂ©aires, rĂ©serves de change, fonctions de rĂ©action de la politique
Dimension Reduction and Model Averaging for Estimation of Artistsâ Age-Valuation Profiles
In hedonic regression models of the valuation of works of art, the age at which an artist produces a particular work, or an indicator variable for periods in his or her artistic career, is often found to have highly significant predictive value. Most existing results are based on regressions that pool large groups of painters. Although it is of interest to estimate such regressions for individual artists, the sample sizes are often inadequate for a model that would also include the large number of other relevant variables. We address this problem of inadequate degrees of freedom in individual artist regressions by using two statistical methods (model averaging and dimension reduction) to incorporate information from a potentially large number of predictor variables, allowing us to work with relatively small samples. We find that individual age-valuation profiles can differ substantially from general pooled profiles, suggesting that methods that are more responsive to the unique features of individual artists may provide better predictions of art valuations at auction. In hedonic regression models of the valuation of works of art, the age at which an artist produces a particular work, or an indicator variable for periods in his or her artistic career, is often found to have highly significant predictive value. Most existing results are based on regressions that pool large groups of painters. Although it is of interest to estimate such regressions for individual artists, the sample sizes are often inadequate for a model that would also include the large number of other relevant variables. We address this problem of inadequate degrees of freedom in individual artist regressions by using two statistical methods (model averaging and dimension reduction) to incorporate information from a potentially large number of predictor variables, allowing us to work with relatively small samples. We find that individual age-valuation profiles can differ substantially from general pooled profiles, suggesting that methods that are more responsive to the unique features of individual artists may provide better predictions of art valuations at auction.Dimension reduction, factor-augmented model, model averaging, réduction de dimension, modÚle de facteur augmenté, moyenne de modÚles
Dynamic Price Dependence of Canadian and International Art Markets: An Empirical Analysis
Although the market for Canadian paintings is now of substantial magnitude, with several works having recently sold for well over a million dollars, it remains true that with very few exceptions, the works of Canadian painters are bought and sold only in Canada and held only by Canadian collectors. This market can thus be viewed as almost exclusively local, and it is therefore not clear that there should be any linkage between price movements for Canadian art and those for the mainstream international market in old master, impressionist, and modern art. This paper investigates the presence and nature of such time series dependence econometrically, both in terms of long term trends as reflected in the co-integrating relationship between Canadian and the international market, and in terms of short-run co-movements as represented in correlations. The possibility that the local market "follows" the international one is also considered through an analysis of Granger-Causality. For Canadian art prices we use a new hedonic index that has been computed using an updated version of the data set of Hodgson and Vorkink (2004), while for the international prices, we use an index provided by Mei and Moses.Alternative investments, Economics of art markets, Market for paintings, Time series analysis, CAPM,
The Impossibility of a Perfectly Competitive Labor Market
Using the institutional theory of transaction cost, I demonstrate that the assumptions of the competitive labor market model are internally contradictory and lead to the conclusion that on purely theoretical grounds a perfectly competitive labor market is a logical impossibility. By extension, the familiar diagram of wage determination by supply and demand is also a logical impossibility and the neoclassical labor demand curve is not a well-defined construct. The reason is that the perfectly competitive market model presumes zero transaction cost and with zero transaction cost all labor is hired as independent contractors, implying multi-person firms, the employment relationship, and labor market disappear. With positive transaction cost, on the other hand, employment contracts are incomplete and the labor supply curve to the firm is upward sloping, again causing the labor demand curve to be ill-defined. As a result, theory suggests that wage rates are always and everywhere an amalgam of an administered and bargained price. Working Paper 06-0
Implementation, mechanisms of impact and key contextual factors involved in outcomes of the Modification of Diet, Exercise and Lifestyle (MODEL) randomised controlled trial in Australian adults: Protocol for a mixed-method process evaluation
Introduction The Modification of Diet, Exercise and Lifestyle (MODEL) study aims to examine the impact of providing visualisation and pictorial representation of advanced structural vascular disease (abdominal aortic calcification), on âhealthfulâ improvements to diet and lifestyle. This paper reports the protocol for the process evaluation for the MODEL study. Methods and analysis The overall aim of the process evaluation is to understand the processes that took place during participation in the MODEL study trial and which elements were effective or ineffective for influencing âhealthfulâ behavioural change, and possible ways of improvement to inform wider implementation strategies. A mixed-method approach will be employed with the use of structured questionnaires and semistructured in-depth interviews. All 200 participants enrolled in the trial will undertake the quantitative component of the study and maximum variation sampling will be used to select a subsample for the qualitative component. The sample size for the qualitative component will be determined based on analytical saturation. Interviews will be digitally recorded and transcribed verbatim. Qualitative data will be analysed thematically and reported according to the Consolidated Criteria for Reporting Qualitative Research (COREQ) guidelines. Ethics and dissemination The MODEL study process evaluation has received approval from Edith Cowan University Human Research Ethics Committee (Project Number: 20513 HODGSON). Written informed consent will be obtained from all participants before they are included in the study. The study results will be shared with the individuals and institutions associated with this study as well as academic audiences through peer-reviewed publication and probable presentation at conferences
Modification of diet, exercise and lifestyle (MODEL) study: a randomised controlled trial protocol
Introduction: Most cardiovascular disease (CVD)-related events could be prevented or substantially delayed with improved diet and lifestyle. Providing information on structural vascular disease may improve CVD risk factor management, but its impact on lifestyle change remains unclear. This study aims to determine whether providing visualisation and pictorial representation of structural vascular disease (abdominal aortic calcification (AAC)) can result in healthful diet and lifestyle change.
Methods and analysis: This study, including men and women aged 60â80 years, is a 12-week, two-arm, multisite randomised controlled trial. At baseline, all participants will have AAC assessed from a lateral spine image captured using a bone densitometer. Participants will then be randomised to receive their AAC results at baseline (intervention group) or a usual care control group that will receive their results at 12 weeks. All participants will receive information about routinely assessed CVD risk factors and standardised (video) diet and lifestyle advice with three simple goals: (1) increase fruit and vegetable (FV) intake by at least one serve per day, (2) improve other aspects of the diet and (3) reduce sitting time and increase physical activity. Clinical assessments will be performed at baseline and 12 weeks.
Outcomes: The primary outcome is a change in serum carotenoid concentrations as an objective measure of FV intake. The study design, procedures and treatment of data will adhere to Standard Protocol Items for Randomized Trials guidelines.
Ethics and dissemination: Ethics approval for this study has been granted by the Edith Cowan University and the Deakin University Human Research Ethics Committees (Project Numbers: 20513 HODGSON and 2019-220, respectively). Results of this study will be published in peer-reviewed academic journals and presented in scientific meetings and conferences. Information regarding consent, confidentiality, access to data, ancillary and post-trial care and dissemination policy has been disclosed in the participant information form
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie
Evaluation of polygenic risk scores for breast and ovarian cancer risk prediction in BRCA1 and BRCA2 mutation carriers
Background: Genome-wide association studies (GWAS) have identified 94 common single-nucleotide polymorphisms (SNPs) associated with breast cancer (BC) risk and 18 associated with ovarian cancer (OC) risk. Several of these are also associated with risk of BC or OC for women who carry a pathogenic mutation in the high-risk BC and OC genes BRCA1 or BRCA2. The combined effects of these variants on BC or OC risk for BRCA1 and BRCA2 mutation carriers have not yet been assessed while their clinical management could benefit from improved personalized risk estimates.
Methods: We constructed polygenic risk scores (PRS) using BC and OC susceptibility SNPs identified through population-based GWAS: for BC (overall, estrogen receptor [ER]-positive, and ER-negative) and for OC. Using data from 15 252 female BRCA1 and 8211 BRCA2 carriers, the association of each PRS with BC or OC risk was evaluated using a weighted cohort approach, with time to diagnosis as the outcome and estimation of the hazard ratios (HRs) per standard deviation increase in the PRS.
Results: The PRS for ER-negative BC displayed the strongest association with BC risk in BRCA1 carriers (HR = 1.27, 95% confidence interval [CI] = 1.23 to 1.31, P = 8.2 x 10(53)). In BRCA2 carriers, the strongest association with BC risk was seen for the overall BC PRS (HR = 1.22, 95% CI = 1.17 to 1.28, P = 7.2 x 10(-20)). The OC PRS was strongly associated with OC risk for both BRCA1 and BRCA2 carriers. These translate to differences in absolute risks (more than 10% in each case) between the top and bottom deciles of the PRS distribution; for example, the OC risk was 6% by age 80 years for BRCA2 carriers at the 10th percentile of the OC PRS compared with 19% risk for those at the 90th percentile of PRS.
Conclusions: BC and OC PRS are predictive of cancer risk in BRCA1 and BRCA2 carriers. Incorporation of the PRS into risk prediction models has promise to better inform decisions on cancer risk management
ACCF/ACR/SCCT/SCMR/ASNC/NASCI/SCAI/SIR 2006 Appropriateness Criteria for Cardiac Computed Tomography and Cardiac Magnetic Resonance ImagingââDeveloped in accordance with the principles and methodology outlined by ACCF: Patel MR, Spertus JA, Brindis RG, Hendel RC, Douglas PS, Peterson ED, Wolk MJ, Allen JM, Raskin IE. ACCF proposed method for evaluating the appropriateness of cardiovascular imaging. J Am Coll Cardiol 2005;46:1606â13. A Report of the American College of Cardiology Foundation Quality Strategic Directions Committee Appropriateness Criteria Working Group, American College of Radiology, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, American Society of Nuclear Cardiology, North American Society for Cardiac Imaging, Society for Cardiovascular Angiography and Interventions, and Society of Interventional Radiology
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