Two-Point Entanglement Near a Quantum Phase Transition

In this work, we study the two-point entanglement S(i,j), which measures the entanglement between two separated degrees of freedom (ij) and the rest of system, near a quantum phase transition. Away from the critical point, S(i,j) saturates with a characteristic length scale $\xi_E$, as the distance |i-j| increases. The entanglement length $\xi_E$ agrees with the correlation length. The universality and finite size scaling of entanglement are demonstrated in a class of exactly solvable one dimensional spin model. By connecting the two-point entanglement to correlation functions in the long range limit, we argue that the prediction power of a two-point entanglement is universal as long as the two involved points are separated far enough.Comment: published versio

Segmentation of liver, its vessels and lesions from CT images for surgical planning

<p>Abstract</p> <p>Background</p> <p>Cancer treatments are complex and involve different actions, which include many times a surgical procedure. Medical imaging provides important information for surgical planning, and it usually demands a proper segmentation, i.e., the identification of meaningful objects, such as organs and lesions. This study proposes a methodology to segment the liver, its vessels and nodules from computer tomography images for surgical planning.</p> <p>Methods</p> <p>The proposed methodology consists of four steps executed sequentially: segmentation of liver, segmentation of vessels and nodules, identification of hepatic and portal veins, and segmentation of Couinaud anatomical segments. Firstly, the liver is segmented by a method based on a deformable model implemented through level sets, of which parameters are adjusted by using a supervised optimization procedure. Secondly, a mixture model is used to segment nodules and vessels through a region growing process. Then, the identification of hepatic and portal veins is performed using liver anatomical knowledge and a vein tracking algorithm. Finally, the Couinaud anatomical segments are identified according to the anatomical liver model proposed by Couinaud.</p> <p>Results</p> <p>Experiments were conducted using data and metrics brought from the liver segmentation competition held in the Sliver07 conference. A subset of five exams was used for estimation of segmentation parameter values, while 15 exams were used for evaluation. The method attained a good performance in 17 of the 20 exams, being ranked as the 6^thbest semi-automatic method when comparing to the methods described on the Sliver07 website (2008). It attained visual consistent results for nodules and veins segmentation, and we compiled the results, showing the best, worst, and mean results for all dataset.</p> <p>Conclusions</p> <p>The method for liver segmentation performed well, according to the results of the numerical evaluation implemented, and the segmentation of liver internal structures were consistent with the anatomy of the liver, as confirmed by a specialist. The analysis provided evidences that the method to segment the liver may be applied to segment other organs, especially to those whose distribution of voxel intensities is nearly Gaussian shaped.</p

Recuperação de pomares de cupuaçuzeiro com clones resistentes à vassoura de bruxa.

Com a ampliação das áreas de cultivo de Theobroma grandiflorum, a enfermidade conhecida como vassoura de bruxa, causada pelo fungo Moniliophthora perniciosa (Stahel) Singer, tornou-se cada vez mais importante. Os cultivos pioneiros do Estado do Pará encontram-se seriamente afetados pela doença, alguns dos quais se encontram inviabilizados devido à baixa produção de frutos. Este trabalho teve por objetivo avaliar a capacidade de quatro cultivares de cupuaçuzeiro em promover a recuperação de um pomar comercial severamente atacado por M. perniciosa, no município de Tomé Açu. Os clones eram enxertados de forma alternada na linha de plantio, para evitar que plantas do mesmo clone ficassem próximas uma das outras. O delineamento experimental foi inteiramente ao acaso, com quatro tratamentos (cultivares Coari, Codajás, Manacapuru e Belém) e vinte repetições. A recuperação da copa das plantas aconteceu, em média, um ano após a enxertia e com dois anos as plantas já produziam os primeiros frutos. As quatros cultivares empregadas tiveram um bom desempenho na recuperação das plantas, avançando de 6 frutos/planta na primeira safra, para 21 frutos/planta na última avaliação realizada em 2010/2011. Nessa safra a produção média foi de 31 kg de frutos/planta, que seriam equivalentes a uma produtividade de 12 t de frutos/ha. As quatro cultivares testadas ficaram livres da vassoura de bruxa.PIBIC-2011

Maconellicoccus hirsutus (Green, 1908) (Hemiptera: Pseudococcidae): exotic pest introduced on vine in the São Francisco Valley.

The pink hibiscus mealybug, Maconellicoccus hirsutusis a polyphagous pest that attacks more than 200 generous and about more than 74 botanical families of cultivated or uncultivated plants. Many of these plants are of economic importance to Brazil, including cotton, cocoa, coffee, coconut, citrus, cucumber, corn, beans, papaya, sweet potatoes, figs, grapes, guavas, peanuts, roses, hibiscusand ornamental palms. However, M. hirsutus was recently introduced in Brazil. This study reported the first time occurence this pest in São Francisco Valley, Northeastern Brazil. After the pest presence alert, samplings were taken inside and around of the plantation of vines. The mealybugs were found attacking all structures of grape plants (Vitis vinifera), native plants of caatinga, weeds, "windbreaks" and fruit trees. In grape plants, the mealybugs inside bunches caused the reduction of the fruits quality and the discard of them, and on the sprouts they cause the inhibition of branches development, compromising at least two harvests. Thus, by severity of the damage, M. hirsutus may be considered one of the most important pests of the grape culture in theregion. The control of this new pest is a big challenge that will require a set of actions including chemical insecticides registration, the development of an effective monitoring plan as well as the search and use of natural enemies adapted to the region

Effects of Isometric Handgrip Training in Patients With Peripheral Artery Disease: A Randomized Controlled Trial

BackgroundMeta‐analyses have shown that isometric handgrip training (IHT) can reduce brachial systolic and diastolic blood pressure (BP) by >6/4 mm Hg, respectively. However, whether IHT promotes these effects among patients with peripheral artery disease, who exhibit severe impairment in cardiovascular function, is currently unknown. This study aimed to evaluate the effects of IHT on the cardiovascular function of patients with peripheral artery disease. Methods and ResultsA randomized controlled trial with peripheral artery disease patients assigned to either the IHT or control group was conducted. The IHT group performed 3 sessions per week, for 8 weeks, of unilateral handgrip exercises, consisting of 4 sets of isometric contractions for 2 minutes at 30% of maximum voluntary contraction and a 4‐minute interval between sets. The control group received a compression ball in order to minimize the placebo effects, representing sham training. The primary outcome was brachial BP. The secondary outcomes were central BP, arterial stiffness parameters, cardiac autonomic modulation, and vascular function. The IHT program reduced diastolic BP (75 [10] mm Hg preintervention versus 72 [11] mm Hg postintervention), with no change in the control group (74 [11] mm Hg preintervention versus 74 [11] mm Hg postintervention), with this between‐group difference being significant (P=0.04). Flow‐mediated dilation improved in the IHT group (6.0% [5.7] preintervention versus 9.7% [5.5] postintervention), with no change in the control group (7.6% [5.5] preintervention versus 7.4% [5.1] postintervention), with this between‐group difference being significant (P=0.04). There was no change in other measured variables over the intervention period. ConclusionsIHT reduced brachial diastolic BP and improved local vascular function in patients with peripheral artery disease