540 research outputs found
LM-Type tests for a Unit Root Allowing for a Break in Trend
We consider LM-type tests for a unit root allowing for a break in trend at an unknown date. In addition to the minimum LM test statistic, we propose new LM-type tests based on the least squares estimator of the break date under the null. We examine asymptotic behavior under the null hypothesis with and without a break. For all the endogenous break tests considered, the limiting distribution when there is a break in slope is not the same as when there is no break. Other authors have obtained similar results in the context of DF-type tests. Since this discrepancy is smaller for the LM-type based on the least squares estimator, smaller size distortions are to be expected when using this test statistic. Simulation experiments confirm the superiority in terms of size, power and break date estimation of the proposed methodUnit Root, Structural Change, Lagrange Multiplier Test, Breaking Trend
Determinants of FDI in Latin America
In this paper we study the determinants of inflows of foreign capital in Latin American countries. We consider the usual factors included in other studies in the literature: market size, infrastructure development, and wages. To obtain a improved measure of market size we adjust GDP by a poverty factor. In addition, we consider indicators of openness of the economy, macroeconomic stability, human capital and the importance of natural resources. We also studied the effects of privatizations. The results obtained provide important guidelines on how a country can attract more foreign direct investment.
Exchange market pressure and the credibility of Macau's currency Board
In this study, we assess the credibility of the currency board arrangement (CBA) of the Macau Special Administrative Region by studying the relationship between exchange market pressure (EMP) and the anchors of a rule-based CBA, namely, interest rate arbitrage, exchange rate arbitrage and economic discipline. A pure CBA signals its credibility by allowing the first two anchors to function automatically and by pursuing sound fiscal policies. The analysis’ results suggest that Macau’s CBA has been characterised by a state of low volatility since late 1992, with the brief exception of the East Asian financial crisis period. The paper’s main finding is that fiscal fundamentals seem to have a more pronounced role in reducing EMP’s variability during periods of low volatility whilst interest rate arbitrage is more important in periods of high volatility. We conclude that Macau’s CBA is credible at present as reflected in the low frequency of observed EMP, in the narrowing of Macau’s interest rate differential vis-à-vis U.S. interest rates and in Macau’s substantial fiscal reserves.
Combining CV and RP data: a note on the relationship between consistency and rationality
In this paper, we show that, when combining revealed (RP) and stated (SP) data, for marginal changes in quality of environmental goods, rationality implies consistency, as the consistency conditions coincide with a subset of the conditions for rationality.combined (RP and SP) individual data; rationality; data consistency
Combining Averting Behavior and Contingent Valuation Data: An Application to Drinking Water Treatment
This paper is an empirical application that combines averting behavior with contingent valuation data. Consistency tests are performed incorporating alternative heteroscedastic structures in the bivariate probit models by taking advantage of the different information content that characterizes each data source. We look at three covariates not yet examined in the literature when combining stated and revealed preferred data to explain the variance in the models: income, the bid in the contingent valuation questionnaire, and the distance between the bid and the averting expenditures with drinking water. The models estimated include between and within data sources heteroscedasticity. The results obtained allow the combination of the two data sources under a common preference structure.averting behavior, combination of data sets, consistency tests, contingent valuation, revealed preferred data
Matrix Assisted Formation of Ferrihydrite Nanoparticles in a Siloxane/Poly(Oxyethylene) Nanohybrid
Matrix-assisted formation of ferrihydrite, an iron oxide hydroxide analogue
of the protein ferritin-core, in a sol-gel derived organic-inorganic hybrid is
reported. The hybrid network (named di-ureasil) is composed of
poly(oxyethylene) chains of different average polymer molecular weights grafted
to siloxane domains by means of urea cross-linkages and accommodates
ferrihydrite nanoparticles. Magnetic measurements, Fourier transform infrared
and nuclear magnetic resonance spectroscopy reveal that the controlled
modification of the polymer molecular weight allows the fine-tuning of the
ability of the hybrid matrix to assist and promote iron coordination at the
organic-inorganic interface and subsequent nucleation and growth of the
ferrihydrite nanoparticles whose core size (2-4 nm) is tuned by the amount of
iron incorporated. The polymer chain length, its arrangement and crystallinity,
are key factors on the anchoring and formation of the ferrihydrite particles.Comment: 7 pages, 6 figures. To be published in J. Mater. Che
Undernutrition and associated factors among hospitalized patients
Background & aims: The identification of modifiable risk factors associated with disease-related undernutrition
at hospital admission will contribute to the development of integrated intervention and control strategies for a timely primary prevention. This study aim was to quantify the association between functional autonomy and undernutrition. Methods: A multicentric cross-sectional study was developed in six public hospitals in Portugal.
Undernutrition risk was assessed using Nutritional Risk Screening 2002, undernutrition status was classified from anthropometry and functional autonomy was evaluated using the Katz Index.
Results: In this sample of 1144 patients, 36% were at undernutrition risk and 9.7% undernourished. In
logistic regression analysis, dependent patients were at an increased risk of undernutrition (OR ¼ 1.69,
95% confidence interval (CI) ¼ 1.20e2.39). The following parameters: illiteracy (OR ¼ 2.45, CI ¼ 1.52e3.96), age (one year increment) (OR ¼ 1.03, CI ¼ 1.02e1.04), male (OR ¼ 1.61, CI ¼ 1.19e2.16), single/divorced/widowed (OR ¼ 1.83, CI ¼ 1.34e2.51) and smoker (OR ¼ 1.55, CI ¼ 1.02e2.35) also increased the undernutrition risk. The impaired functional status, being single, divorced or widowed and
be a smoker were also associated with anthropometric undernutrition. Conclusions: Functional impairment is related with undernutrition risk and with anthropometrical undernutrition at hospital admission. We also conclude that little extra information is gained by using anthropometrical indices compared to NRS 2002 when assessing the factors associated with undernutrition.info:eu-repo/semantics/publishedVersio
Blue and green upconversion in Er(3+)-doped fluoroindate glasses
The upconversion properties of Er3+ in fluoroindate bulk glasses (composition: 40InF3-20ZnF2-16BaF2-(20-x)SrF2-2GaF3-2NaF-xErF3 with x=1,2,3 and 4 mole %) are investigated, following F-4(9/2) excitation with a red krypton laser. A strong green and a weaker blue luminescence is observed at room temperature corresponding to emissions from the thermally coupled S-4(3/2) and H-2(11/2) bands and the H-2(9/2) level respectively. Resonant energy transfer processes involving two excited erbium ions and a two-step absorption process are proposed to explain the upconversion phenomena. The emission intensities depend on the excitation power as P(exc)n with 1.5 less-than-or-equal-to n less-than-or-equal-to 1.7 for the green and 1.6 less-than-or-equal-to n less-than-or-equal-to 1.9 for the blue emission. The decay times and the relative intensities of the luminescences are also studied as a function of Er3+ concentration
The state of the dark energy equation of state circa 2023
We critically examine the state of current constraints on the dark energy
(DE) equation of state (EoS) . Our study is partially motivated by the
observation that, while broadly consistent with the cosmological constant value
, several independent probes appear to point towards a slightly phantom
EoS (). We pay attention to the apparent preference for phantom
DE from Planck Cosmic Microwave Background (CMB) data alone, whose origin we
study in detail and attribute to a wide range of (physical and geometrical)
effects. We deem the combination of Planck CMB, Baryon Acoustic Oscillations,
Type Ia Supernovae, and Cosmic Chronometers data to be particularly
trustworthy, inferring from this final consensus dataset
, in excellent agreement with the cosmological
constant value. Overall, despite a few scattered hints, we find no compelling
evidence forcing us away from the cosmological constant (yet).Comment: 21 pages, 10 figures, 3 table
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