Relative Goods' Prices, Pure Inflation, and the Phillips Correlation

This paper uses a dynamic factor model for the quarterly changes in consumption goods’ prices to separate them into three independent components: idiosyncratic relative-price changes, a low-dimensional index of aggregate relative-price changes, and an index of equiproportional changes in all inflation rates, that we label “pure” inflation. The paper estimates the model on U.S. data since 1959, and it presents a simple structural model that relates the three components of price changes to fundamental economic shocks. We use the estimates of the pure inflation and aggregate relative-price components to answer two questions. First, what share of the variability of inflation is associated with each component, and how are they related to conventional measures of monetary policy and relative-price shocks? We find that pure inflation accounts for 15-20% of the variability in inflation while our aggregate relative-price index accounts most of the rest. Conventional measures of relative prices are strongly but far from perfectly correlated with our relative-price index; pure inflation is only weakly correlated with money growth rates, but more strongly correlated with nominal interest rates. Second, what drives the Phillips correlation between inflation and measures of real activity? We find that the Phillips correlation essentially disappears once we control for goods’ relative-price changes. This supports modern theories of inflation dynamics based on price rigidities and many consumption goods.

Slum health: diseases of neglected populations.

BackgroundUrban slums, like refugee communities, comprise a social cluster that engenders a distinct set of health problems. With 1 billion people currently estimated to live in such communities, this neglected population has become a major reservoir for a wide spectrum of health conditions that the formal health sector must deal with.DiscussionUnlike what occurs with refugee populations, the formal health sector becomes aware of the health problems of slum populations relatively late in the course of their illnesses. As such, the formal health sector inevitably deals with the severe and end-stage complications of these diseases at a substantially greater cost than what it costs to manage non-slum community populations. Because of the informal nature of slum settlements, and cultural, social, and behavioral factors unique to the slum populations, little is known about the spectrum, burden, and determinants of illnesses in these communities that give rise to these complications, especially of those diseases that are chronic but preventable. In this article, we discuss observations made in one slum community of 58,000 people in Salvador, the third largest city in Brazil, to highlight the existence of a spectrum and burden of chronic illnesses not likely to be detected by the formal sector health services until they result in complications or death. Lack of health-related data from slums could lead to inappropriate and unrealistic allocation of health care resources by the public and private providers. Similar misassumptions and misallocations are likely to exist in other nations with large urban slum populations.SummaryContinued neglect of ever-expanding urban slum populations in the world could inevitably lead to greater expenditure and diversion of health care resources to the management of end-stage complications of diseases that are preventable. A new approach to health assessment and characterization of social-cluster determinants of health in urban slums is urgently needed

Cluster growth in far-from-equilibrium particle models with diffusion, detachment, reattachment and deposition

Monolayer cluster growth in far-from-equilibrium systems is investigated by applying simulation and analytic techniques to minimal hard core particle (exclusion) models. The first model (I), for post-deposition coarsening dynamics, contains mechanisms of diffusion, attachment, and slow activated detachment (at rate epsilon<<1) of particles on a line. Simulation shows three successive regimes of cluster growth: fast attachment of isolated particles; detachment allowing further (epsilon t)^(1/3) coarsening of average cluster size; and t^(-1/2) approach to a saturation size going like epsilon^(-1/2). Model II generalizes the first one in having an additional mechanism of particle deposition into cluster gaps, suppressed for the smallest gaps. This model exhibits early rapid filling, leading to slowing deposition due to the increasing scarcity of deposition sites, and then continued power law (epsilon t)^(1/2) cluster size coarsening through the redistribution allowed by slow detachment. The basic (epsilon t)^(1/3) domain growth laws and epsilon^(-1/2) saturation in model I are explained by a simple scaling picture. A second, fuller approach is presented which employs a mapping of cluster configurations to a column picture and an approximate factorization of the cluster configuration probability within the resulting master equation. This allows quantitative results for the saturation of model I in excellent agreement with the simulation results. For model II, it provides a one-variable scaling function solution for the coarsening probability distribution, and in particular quantitative agreement with the cluster length scaling and its amplitude.Comment: Accepted in Phys. Rev. E; 9 pages with figure

Mapping the interface between the Local and Loop I bubbles using Stromgren photometry

The Sun is located inside an extremely low density region of quite irregular shape called the Local Bubble. Close to the Local Bubble, there is an even larger cavity known as Loop I. A ring-like feature observed in X-ray and HI has been proposed as the contour of the bubbles interaction zone around 70 pc. Our goal is to identify the interface between the Local and Loop I Bubbles and discuss the ring's existence using Stromgren uvbyH\beta data. We have used the uvbyH\beta data of the General Catalogue of Photometric Data, covering the region defined by the Galactic coordinates: 250\degr <= l <= 50\degr and -60\degr <= b <= 60\degr to obtain E(b-y) colour excess and distances. The final sample is composed of 4346 stars located up to 500 pc from the Sun. The expected transition to E(b-y) ~ 0.070 - 0.100 mag, corresponding to the ring's column density, occurs on the western part of the ring at d = 110 +/- 20 pc, whereas on the eastern side it is not clearly seen before d = 280 +/- 50 pc. Near the Galactic plane the presence of the dark clouds is clearly established by E(b-y) >= 0.100 mag on the western side at about 100 - 150 pc and about 120 - 180 pc on the eastern side. In the southernmost part of the ring the reddening remains very low, typically E(b-y) = 0.020 in all its extension, except towards the Mensa constellation where a possible transition is observed at d = 200 +/- 20 pc. In the northernmost part the colour excess increases with distance in a gradual way, such that 0.020 <= E(b-y) <= 0.040 mag becomes predominant only after d=120 +/-15 pc. If the ring really exists the colour excess distribution indicates that it is very fragmented and distorted. However, the different characteristics of the reddening inside and along the ring do not support the existence of a ring.Comment: 16 pages, 15 figures, accepted for publication in Astronomy and Astrophysic

Atividade externa carregamento de isca granulada e controle de Acromyrmex crassispinus em floresta de Pinus taeda.

bitstream/CNPF-2009-09/32741/1/com_tec78.pd

Caging dynamics in a granular fluid

We report an experimental investigation of the caging motion in a uniformly heated granular fluid, for a wide range of filling fractions, $\phi$. At low $\phi$ the classic diffusive behavior of a fluid is observed. However, as $\phi$ is increased, temporary cages develop and particles become increasingly trapped by their neighbors. We statistically analyze particle trajectories and observe a number of robust features typically associated with dense molecular liquids and colloids. Even though our monodisperse and quasi-2D system is known to not exhibit a glass transition, we still observe many of the precursors usually associated with glassy dynamics. We speculate that this is due to a process of structural arrest provided, in our case, by the presence of crystallization.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let

Final state interaction in D+→K−π+π+D^+\to K^-\pi^+\pi^+ with KπK\pi I=1/2 and 3/2 channels

The final state interaction contribution to $D^+$ decays is computed for the $K^-\pi^+\pi^+$ channel within a light-front relativistic three-body model for the final state interaction. The rescattering process between the kaon and two pions in the decay channel is considered. The off-shell decay amplitude is a solution of a four-dimensional Bethe-Salpeter equation, which is decomposed in a Faddeev form. The projection onto the light-front of the coupled set of integral equations is performed via a quasi-potential approach. The S-wave $K\pi$ interaction is introduced in the resonant isospin $1/2$ and the non-resonant isospin $3/2$ channels. The numerical solution of the light-front tridimensional inhomogeneous integral equations for the Faddeev components of the decay amplitude is performed perturbatively. The loop-expansion converges fast, and the three-loop contribution can be neglected in respect to the two-loop results for the practical application. The dependence on the model parameters in respect to the input amplitude at the partonic level is exploited and the phase found in the experimental analysis, is fitted with an appropriate choice of the real weights of the isospin components of the partonic amplitude. The data suggests a small mixture of total isospin $5/2$ to the dominant $3/2$ one. The modulus of the unsymmetrized decay amplitude, which presents a deep valley and a following increase for $K\pi$ masses above $1.5$ GeV, is fairly reproduced. This suggests the assignment of the quantum numbers $0^+$ to the isospin 1/2 $K^*(1630)$ resonance

Ising-type Magnetic Anisotropy in CePd2_2As2_2

We investigated the anisotropic magnetic properties of CePd$_2$As$_2$ by magnetic, thermal and electrical transport studies. X-ray diffraction confirmed the tetragonal ThCr$_2$Si$_2$-type structure and the high-quality of the single crystals. Magnetisation and magnetic susceptibility data taken along the different crystallographic directions evidence a huge crystalline electric field (CEF) induced Ising-type magneto-crystalline anisotropy with a large $c$-axis moment and a small in-plane moment at low temperature. A detailed CEF analysis based on the magnetic susceptibility data indicates an almost pure $\langle\pm5/2 \rvert$ CEF ground-state doublet with the dominantly $\langle\pm3/2 \rvert$ and the $\langle\pm1/2 \rvert$ doublets at 290 K and 330 K, respectively. At low temperature, we observe a uniaxial antiferromagnetic (AFM) transition at $T_N=14.7$ K with the crystallographic $c$-direction being the magnetic easy-axis. The magnetic entropy gain up to $T_N$ reaches almost $R\ln2$ indicating localised $4f$-electron magnetism without significant Kondo-type interactions. Below $T_N$, the application of a magnetic field along the $c$-axis induces a metamagnetic transition from the AFM to a field-polarised phase at $\mu_0H_{c0}=0.95$ T, exhibiting a text-book example of a spin-flip transition as anticipated for an Ising-type AFM.Comment: 9 Pages, 8 figure

Pragas florestais associadas a problemas silviculturais.

bitstream/item/38120/1/iede.pdfSeção Artigos Técnicos