Critical behavior at edge singularities in one dimensional spin models

In ferromagnetic spin models above the critical temperature ($T > T_{cr}$) the partition function zeros accumulate at complex values of the magnetic field ($H_E$) with a universal behavior for the density of zeros \rho (H) \sim | H - H_E |^{\sg}. The critical exponent \sg is believed to be universal at each space dimension and it is related to the magnetic scaling exponent $y_h$ via \sg = (d-y_h)/y_h. In two dimensions we have y_h=12/5 (\sg = -1/6) while y_h=2 (\sg=-1/2) in $d=1$. For the one dimensional Blume-Capel and Blume-Emery-Griffiths models we show here, for different temperatures, that a new value y_h=3 (\sg =-2/3) can emerge if we have a triple degeneracy of the transfer matrix eigenvalues.Comment: to appear in Phys. Rev. E, 16 pages, 3 figure

Shifts in Portfolio Preferences of International Investors: An Application to Sovereign Wealth Funds

Reversals in capital inflows can have severe economic consequences. This paper develops a dynamic general equilibrium model to analyse the effect on interest rates, asset prices, investment, consumption, output, the exchange rate and the current account of a shift in portfolio preferences of foreign investors. The model has two countries and two asset classes (equities and bonds). It is characterized by imperfect substitutability between assets and allows for endogenous adjustment in interest rates and asset prices. Therefore, it accounts for capital gains arising from equity price movements, in addition to valuation effects caused by changes in the exchange rate. To illustrate the mechanics of the model, we calibrate it to analyse the consequences of an increase in the importance of Sovereign Wealth Funds (SWFs). Specifically, we ask what would happen if 'excess' reserves held by Emerging Markets were transferred from central banks to SWFs. We look separately at two diversification paths: one in which SWFs keep the same allocation across bonds and equities as central banks, but move away from dollar assets (path 1); and another in which they choose the same currency composition as central banks, but shift from US bonds to US equities (path 2). In path 1, the dollar depreciates and US net debt falls on impact and increases in the long run. In path 2, the dollar depreciates and US net debt increases in the long run. In both cases, there is a reduction in the 'exorbitant privilege', i.e., the excess return the US receives on its assets over what it pays on its liabilities. The model is applicable to other episodes in which foreign investors change the composition of their portfolios

Monetary Policy, Capital Inflows, and the Housing Boom

We estimate an open economy VAR model to quantify the effect of monetary policy and capital inflows shocks on the US housing market. The shocks are identified with sign restrictions derived from a standard DSGE model. We find that monetary policy shocks have a limited effect on house prices and residential investment. In contrast, capital inflows shocks driven by an increase in foreign savings have a positive and persistent effect on both housing variables. Other sources of capital inflows shocks, such as foreign monetary expansion or an increase in aggregate demand in the US, have a more limited role

Estudo das combinação de fertilizantes orgânicos e químicos na produção da massa foliar da sacaca (Croton cajucara Benth).

Informações sobre práticas fitotécnicas para eficientizar o cultivo de sacaca e, assim, fornecer indicações agrícolas para a melhoria do nível de qualidade dos produtos fitoterápicos no Amazonas.bitstream/CPAA-2009-09/2732/1/Com_Tec_13.pd

Capacitive Coupling of Two Transmission Line Resonators Mediated by the Phonon Number of a Nanoelectromechanical Oscillator

Detection of quantum features in mechanical systems at the nanoscale constitutes a challenging task, given the weak interaction with other elements and the available technics. Here we describe how the interaction between two monomodal transmission-line resonators (TLRs) mediated by vibrations of a nano-electromechanical oscillator can be described. This scheme is then employed for quantum non-demolition detection of the number of phonons in the nano-electromechanical oscillator through a direct current measurement in the output of one of the TLRs. For that to be possible an undepleted field inside one of the TLR works as a amplifier for the interaction between the mechanical resonator and the remaining TLR. We also show how how the non-classical nature of this system can be used for generation of tripartite entanglement and conditioned mechanical coherent superposition states, which may be further explored for detection processes.Comment: 6 pages, 5 figure

Caracterização Geoquímica de Jazigos Filonianos de Pb-Zn-(Ag) através do Estudo Estatístico dos Teores em Elementos Menores em Sulfuretos

Sulfides from Portuguese Vein-type Pb-Zn-(Ag) deposits were analysed with electronic microprobe. The results obtained for several minor elements present in galena and sphalerite were then statistically studied using principal components analysis (PCA). We intend to contribute to the geochemical characterization of these deposits through their contents in the minor elements. We hope to distinguish different subtypes of vein Pb-Zn-(Ag) deposits through the statistical analysis of minor elements present in sulfide