Impacto do aumento da concentração de CO2 atmosférico sobre a microbiota do solo rizosférico de arroz.

A intensificação da atividade antrópica está causando significativo aumento da concentração de dióxido de carbono (CO2) na atmosfera, resultando em alterações no clima do planeta que devem ser acentuadas nas próximas décadas. Além das mudanças climáticas previstas, impactos também ocorrerão no ambiente biótico. O trabalho teve por objetivo avaliar os efeitos do aumento do CO2 atmosférico na microbiota do solo rizosférico de arroz (cultivar Agulha Precoce), em ensaio conduzido em estufas de topo aberto. Os tratamentos com injeção automatizada do gás apresentaram concentração média de 613 ppm de CO2. Como testemunha, foram utilizadas parcelas sem estufa e sem injeção do gás. Não houve efeito dos tratamentos no carbono da biomassa microbiana, na hidrólise de diacetato de fluoresceína, no desprendimento de CO2 e na condutividade elétrica do solo rizosférico e no número de bactérias diazotróficas endofíticas isoladas das raízes utilizando-se meio de cultura JNFb semi-específico para Herbaspirillum. Os tratamentos com estufa apresentaram aumento do pH do solo, sendo que o maior aumento foi obtido no tratamento com injeção de CO2

Strong low-frequency quantum correlations from a four-wave mixing amplifier

We show that a simple scheme based on nondegenerate four-wave mixing in a hot atomic vapor behaves like a near-perfect phase-insensitive optical amplifier, which can generate bright twin beams with a measured quantum noise reduction in the intensity difference of more than 8 dB, close to the best optical parametric amplifiers and oscillators. The absence of a cavity makes the system immune to external perturbations, and the strong quantum noise reduction is observed over a large frequency range.Comment: 4 pages, 4 figures. Major rewrite of the previous version. New experimental results and further analysi

Duality, Quantum Skyrmions and the Stability of an SO(3) Two-Dimensional Quantum Spin-Glass

Quantum topological excitations (skyrmions) are analyzed from the point of view of their duality to spin excitations in the different phases of a disordered two-dimensional, short-range interacting, SO(3) quantum magnetic system of Heisenberg type. The phase diagram displays all the phases, which are allowed by the duality relation. We study the large distance behavior of the two-point correlation function of quantum skyrmions in each of these phases and, out of this, extract information about the energy spectrum and non-triviality of these excitations. The skyrmion correlators present a power-law decay in the spin-glass(SG)-phase, indicating that these quantum topological excitations are gapless but nontrivial in this phase. The SG phase is dual to the AF phase, in the sense that topological and spin excitations are respectively gapless in each of them. The Berezinskii-Kosterlitz-Thouless mechanism guarantees the survival of the SG phase at $T \neq 0$, whereas the AF phase is washed out to T=0 by the quantum fluctuations. Our results suggest a new, more symmetric way of characterizing a SG-phase: one for which both the order and disorder parameters vanish, namely $= 0$, $=0$, where $\sigma$ is the spin and $\mu$ is the topological excitation operators.Comment: 10 pages, 1 figur

A kg-mass prototype demonstrator for DUAL gravitational wave detector: opto-mechanical excitation and cooling

The next generation of gravitational wave (gw) detectors is expected to fully enter into the quantum regime of force and displacement detection. With this aim, it is important to scale up the experiments on opto-mechanical effects from the microscopic regime to large mass systems and test the schemes that should be applied to reach the quantum regime of detection. In this work we present the experimental characterization of a prototype of massive gw detector, composed of two oscillators with a mass of the order of the kg, whose distance is read by a high finesse optical cavity. The mechanical response function is measured by exciting the oscillators though modulated radiation pressure. We demonstrate two effects crucial for the next generation of massive, cryogenic gw detectors (DUAL detectors): a) the reduction of the contribution of 'local' susceptibility thanks to an average over a large interrogation area. Such effect is measured on the photo-thermal response thanks to the first implementation of a folded-Fabry-Perot cavity; b) the 'back-action reduction' due to negative interference between acoustic modes. Moreover, we obtain the active cooling of an oscillation mode through radiation pressure, on the described mechanical device which is several orders of magnitude heavier than previously demonstrated radiation-pressure cooled systems

Number statistics for β\beta-ensembles of random matrices: applications to trapped fermions at zero temperature

Let $\mathcal{P}_{\beta}^{(V)} (N_{\cal I})$ be the probability that a $N\times N$ $\beta$-ensemble of random matrices with confining potential $V(x)$ has $N_{\cal I}$ eigenvalues inside an interval ${\cal I}=[a,b]$ of the real line. We introduce a general formalism, based on the Coulomb gas technique and the resolvent method, to compute analytically $\mathcal{P}_{\beta}^{(V)} (N_{\cal I})$ for large $N$. We show that this probability scales for large $N$ as $\mathcal{P}_{\beta}^{(V)} (N_{\cal I})\approx \exp\left(-\beta N^2 \psi^{(V)}(N_{\cal I} /N)\right)$, where $\beta$ is the Dyson index of the ensemble. The rate function $\psi^{(V)}(k_{\cal I})$, independent of $\beta$, is computed in terms of single integrals that can be easily evaluated numerically. The general formalism is then applied to the classical $\beta$-Gaussian (${\cal I}=[-L,L]$), $\beta$-Wishart (${\cal I}=[1,L]$) and $\beta$-Cauchy (${\cal I}=[-L,L]$) ensembles. Expanding the rate function around its minimum, we find that generically the number variance ${\rm Var}(N_{\cal I})$ exhibits a non-monotonic behavior as a function of the size of the interval, with a maximum that can be precisely characterized. These analytical results, corroborated by numerical simulations, provide the full counting statistics of many systems where random matrix models apply. In particular, we present results for the full counting statistics of zero temperature one-dimensional spinless fermions in a harmonic trap.Comment: 34 pages, 19 figure

Inflammatory markers as prognostic factors of survival in patients affected by hepatocellular carcinoma undergoing transarterial chemoembolization

Transarterial chemoembolization (TACE) is a good choice for hepatocellular carcinoma (HCC) treatment when surgery and liver transplantation are not feasible. Few studies reported the value of prognostic factors influencing survival after chemoembolization. In this study, we evaluated whether preoperative inflammatory factors such as neutrophil to lymphocyte ratio and platelet to lymphocyte ratio affected our patient survival when affected by hepatocellular carcinoma. Methods. We retrospectively evaluated a total of 72 patients with hepatocellular carcinoma that underwent TACE. We enrolled patients with different etiopathogeneses of hepatitis and histologically proven HCC not suitable for surgery. The overall study population was dichotomized in two groups according to the median NLR value and was analyzed also according to other prognostic factors. Results. The global median overall survival (OS) was 28 months. The OS in patients with high NLR was statistically significantly shorter than that in patients with low NLR. The following pretreatment variables were significantly associated with the OS in univariate analyses: age, Child-Pugh score, BCLC stage, INR, and NLR. Pretreated high NLR was an independently unfavorable factor for OS. Conclusion. NLR could be considered a good prognostic factor of survival useful to stratify patients that could benefit from TACE treatment

Postpubertal effects of the rapid maxillary expansion and facial mask versus the removable mandibular retractor for the early treatment of class iii malocclusion: A study on lateral cephalograms

The aim of this study was to compare the efficacy of early treatment of Class III malocclusions with rapid maxillary expansion (RME) and facial mask (FM) versus the removable mandibular retractor (RMR) re-evaluated at a postpubertal observation on lateral cephalograms. All prepubertal patients with Class III malocclusion treated consecutively from 1986 to 2013 by means of RME/FM or RMR were analyzed. Twenty-nine patients treated with RME/FM therapy and 23 patients treated with RMR were selected. Lateral cephalograms were available at 3 time points, before treatment (T1), at the end of active treatment (T2), and at a postpubertal observation (T3). Statistical comparisons were performed with independent sample t tests or Mann–Whitney tests. During the T1–T3 interval, a significantly greater maxillary protraction (SNA +1.5 mm, p = 0.031) and significantly greater improvements in ANB and Wits appraisal (+1.9 degrees, p = 0.002, and +2.2 mm, p = 0.012, respectively) were recorded in the RME/FM group. No statistically significant changes could be found in vertical skeletal measurements. In the dentoalveolar region, the RME/FM group showed a significantly greater correction of the molar relationship (−1.5 mm, p = 0.021). Early treatment of Class III malocclusion with RME/FM protocol in comparison with RMR protocol showed a greater maxillary advancement and greater improvements in sagittal skeletal Class III relationships

Gravitational Waveguides in Cosmology

We discuss the possibility that, besides the usual gravitational lensing, there may exist a sort of gravitational waveguiding in cosmology which could explain some anomalous phenomena which cannot be understood by the current gravitational lensing models as the existence of "brothers" objects having different brilliancy but similar spectra and redshifts posed on the sky with large angular distance. Furthermore, such a phenomena could explain the huge luminosities coming from quasars using the cosmological structures as selfoc-type or planar waveguide. We describe the gravitational waveguide theory and then we discuss possible realizations in cosmology.Comment: 14 pages, latex, submitted to Int. Jou. Mod. Phys.