120 research outputs found
The Macroeconomic Determinants of Volatility in Precious Metals Markets
We investigate key macroeconomic factors that impact the price returns of precious metals markets. The markets investigated were gold, silver, platinum and palladium; whereas the macroeconomic factors accommodated business cycle, monetary environment and financial market sentiment factors. The key findings present limited evidence that the same macroeconomic factors jointly influence the volatility processes of the precious metal price series, although there is some evidence of volatility feedback between the precious metals. This finding lends weight to views that individual commodities are too distinct to be considered a single asset class or represented by a single index; a finding of considerable importance for portfolio managers and investors.
Syn-tectonic sedimentary evolution of the Miocene Çatallar Basin, southwestern Turkey
International audienceThe Çatallar Basin is one of the Miocene basins located in the southern part of the Bey Dağları Massif (SW Turkey). This basin has been reinvestigated and new stratigraphic and sedimentological data are now presented. The Çatallar Basin lies in paraconformity on the Bey Dağları carbonate platform of Late Cretaceous to Palaeogene age. It consists of an impersistent, shallow-marine carbonate base (Karabayır formation, Late Oligocene to Early Burdigalian) followed by an onlapping detrital sequence including the Akçay and Bağbeleni formations (Langhian to Serravallian). The Akçay formation mainly contains turbidites in which several debris-flows and olistostromes are intercalated. The lowest debris flows derive from the local carbonate platforms of Cretaceous and Palaeogene age. Higher, the debris flows and olistostromes contain large carbonate blocks deriving from nearby sources (Bey Dağları platform carbonates), whereas the accompanying pebbles originate from the allochthonous ophiolitic units located farther to the north (Lycian Nappes) or to the east (Antalya Nappes). The origin of these ophiolitic detritus is a matter of debate. The new data obtained in this study favour a northern origin
Influence of fogging lenses and cycloplegia on open-field automatic refraction
Purpose: To compare refractive values measured without cycloplegia, cycloplegia and fogging lenses using an open-field auto-refractor.
Methods: One hundred and forty-two young adults were enrolled from a university population; 96 were female (67.6%) and 46 were male (32.4%), the age range was 18 to 26 years (mean 22.3 ± 3.7 years). The refraction measurement was obtained with autorefractor Grand Seiko Auto Ref/Keratometer WAM-5500 (GS) under three conditions, always in this sequence: 1) without cycloplegia (GS), 2) without cycloplegia but using a +2.00D fogging lens (GS_2D) and 3) with cycloplegia (GS_cycl).
Results: When the average values of spherical equivalent were compared both accommodation control strategies were almost equally successful: GS, M= -0.85 ± 2.21 D; GC_2D, M= -0.53 ± 2.10 D and GS_cycl, M= -0.57 ± 2.24 D (Kruskal-Wallis Test, p<0.001). When the results were analyzed separately for different refractive groups, emmetropes and hyperopes show statistically significant differences while myopes did not. When both accommodation strategies were compared there was a trend for more myopic subject to display more negative values under cycloplegia, while low myopes, emmetropes and hyperopes tend to display more negative values with the +2.00 D fogging lenses (less effectiveness of accommodation control).
Conclusions: Over-refraction through +2.00 D fogging lenses is useful to achieve additional relaxation of the accommodative response in a similar way than cycloplegia when open-field autorefraction is performed in young adults.Grand Seiko Auto Ref/Keratometer WAM-5500
Conditional Correlations and Volatility Spillovers between Crude Oil and Stock Index Returns
Can urban coffee consumption help predict US inflation?
Motivated by the importance of coffee to Americans and the significance of the coffee subsector to the US economy, we pursue three notable innovations. First, we augment the traditional Phillips curve model with the coffee price as a predictor, and show that the resulting model outperforms the traditional variant in both in-sample and out-of-sample predictability of US inflation. Second, we demonstrate the need to account for the inherent statistical features of predictors such as persistence, endogeneity, and conditional heteroskedasticity effects when dealing with US inflation. Consequently, we offer robust illustrations to show that the choice of estimator matters for improved US inflation forecasts. Third, the proposed augmented Phillips curve also outperforms time series models such as autoregressive integrated moving average and the fractionally integrated version for both in-sample and out-of-sample forecasts. Our results show that augmenting the traditional Phillips curve with the urban coffee price will produce better forecast results for US inflation only when the statistical effects are captured in the estimation process. Our results are robust to alternative measures of inflation, different data frequencies, higher order moments, multiple data samples and multiple forecast horizons
Financial and monetary policy responses to oil price shocks: evidence from oil-importing and oil-exporting countries
In this study, we investigate the financial and monetary policy responses to oil price shocks using a Structural VAR framework. We distinguish between net oil-importing and net oil-exporting countries. Since the 80s, a significant number of empirical studies have been published investigating the effect of oil prices on macroeconomic and financial variables. Most of these studies though, do not make a distinction between oil-importing and oil-exporting economies. Overall, our results indicate that the level of inflation in both net oil-exporting and net oil-importing countries is significantly affected by oil price innovations. Furthermore, we find that the response of interest rates to an oil price shock depends heavily on the monetary policy regime of each country. Finally, stock markets operating in net oil-importing countries exhibit a negative response to increased oil prices. The reverse is true for the stock market of the net oil-exporting countries. We find evidence that the magnitude of stock market responses to oil price shocks is higher for the newly established and/or less liquid stock market
PAX6 Haplotypes Are Associated with High Myopia in Han Chinese
Author name used in this publication: Maurice K. H. Yap2010-2011 > Academic research: refereed > Publication in refereed journalpublished_fina
Genome-Wide Meta-Analysis of Five Asian Cohorts Identifies PDGFRA as a Susceptibility Locus for Corneal Astigmatism
Corneal astigmatism refers to refractive abnormalities and irregularities in the curvature of the cornea, and this interferes with light being accurately focused at a single point in the eye. This ametropic condition is highly prevalent, influences visual acuity, and is a highly heritable trait. There is currently a paucity of research in the genetic etiology of corneal astigmatism. Here we report the results from five genome-wide association studies of corneal astigmatism across three Asian populations, with an initial discovery set of 4,254 Chinese and Malay individuals consisting of 2,249 cases and 2,005 controls. Replication was obtained from three surveys comprising of 2,139 Indians, an additional 929 Chinese children, and an independent 397 Chinese family trios. Variants in PDGFRA on chromosome 4q12 (lead SNP: rs7677751, allelic odds ratio = 1.26 (95% CI: 1.16–1.36), Pmeta = 7.87×10−9) were identified to be significantly associated with corneal astigmatism, exhibiting consistent effect sizes across all five cohorts. This highlights the potential role of variants in PDGFRA in the genetic etiology of corneal astigmatism across diverse Asian populations
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