An evolutionary approach for the motion planning of redundant and hyper-redundant manipulators

The trajectory planning of redundant robots is an important area of research and efficient optimization algorithms are needed. The pseudoinverse control is not repeatable, causing drift in joint space which is undesirable for physical control. This paper presents a new technique that combines the closed-loop pseudoinverse method with genetic algorithms, leading to an optimization criterion for repeatable control of redundant manipulators, and avoiding the joint angle drift problem. Computer simulations performed based on redundant and hyper-redundant planar manipulators show that, when the end-effector traces a closed path in the workspace, the robot returns to its initial configuration. The solution is repeatable for a workspace with and without obstacles in the sense that, after executing several cycles, the initial and final states of the manipulator are very close

An evolutionary approach to the trajectory planning of redundant robots

Several kinematic techniques for the trajectory optimization of redundant manipulators control the gripper using the pseudoinverse of the Jacobian. Nevertheless, these algorithms lead to a kind of chaotic motion with unpredictable arm configurations. This paper presents a new technique for solving the inverse kinematics problem for redundant manipulators that combines the closed-loop pseudoinverse method with genetic algorithms.N/

Deep Sequencing Analysis of RNAs from Citrus Plants Grown in a Citrus Sudden Death-Affected Area Reveals Diverse Known and Putative Novel Viruses.

Citrus sudden death (CSD) has caused the death of approximately four million orange trees in a very important citrus region in Brazil. Although its etiology is still not completely clear, symptoms and distribution of affected plants indicate a viral disease. In a search for viruses associated with CSD, we have performed a comparative high-throughput sequencing analysis of the transcriptome and small RNAs from CSD-symptomatic and -asymptomatic plants using the Illumina platform. The data revealed mixed infections that included Citrus tristeza virus (CTV) as the most predominant virus, followed by the Citrus sudden death-associated virus (CSDaV), Citrus endogenous pararetrovirus (CitPRV) and two putative novel viruses tentatively named Citrus jingmen-like virus (CJLV), and Citrus virga-like virus (CVLV). The deep sequencing analyses were sensitive enough to differentiate two genotypes of both viruses previously associated with CSD-affected plants: CTV and CSDaV. Our data also showed a putative association of the CSD-symptomatic plants with a specific CSDaV genotype and a likely association with CitPRV as well, whereas the two putative novel viruses showed to be more associated with CSD-asymptomatic plants. This is the first high-throughput sequencing-based study of the viral sequences present in CSD-affected citrus plants, and generated valuable information for further CSD studies

Fractional-order harmonics in the trajectory control of redundant manipulators

Redundant manipulators are superior to classical arms because they allow the trajectory optimization, the obstacle avoidance, and the resolution of singularities. For this type of manipulators, the kinematic control algorithms adopt generalized inverse matrices that may lead to unpredictable responses. Motivated by these problems this paper studies the complexity revealed by the trajectory planning scheme when controlling redundant manipulators. The result reveals a chaotic phenomenon and the existence of fractional order sub-harmonics in the robot signals.N/

Analysis of the biofilm proteome of Xylella fastidiosa

<p>Abstract</p> <p>Background</p> <p><it>Xylella fastidiosa </it>is limited to the xylem of the plant host and the foregut of insect vectors (sharpshooters). The mechanism of pathogenicity of this bacterium differs from other plant pathogens, since it does not present typical genes that confer specific interactions between plant and pathogens (avr and/or hrp). The bacterium is injected directly into the xylem vessels where it adheres and colonizes. The whole process leads to the formation of biofilms, which are considered the main mechanism of pathogenicity. Cells in biofilms are metabolically and phenotypically different from their planktonic condition. The mature biofilm stage (phase of higher cell density) presents high virulence and resistance to toxic substances such as antibiotics and detergents. Here we performed proteomic analysis of proteins expressed exclusively in the mature biofilm of <it>X. fastidiosa </it>strain 9a5c, in comparison to planktonic growth condition.</p> <p>Results</p> <p>We found a total of 456 proteins expressed in the biofilm condition, which correspond to approximately 10% of total protein in the genome. The biofilm showed 37% (or 144 proteins) different protein than we found in the planktonic growth condition. The large difference in protein pattern in the biofilm condition may be responsible for the physiological changes of the cells in the biofilm of <it>X. fastidiosa</it>. Mass spectrometry was used to identify these proteins, while real-time quantitative polymerase chain reaction monitored expression of genes encoding them. Most of proteins expressed in the mature biofilm growth were associated with metabolism, adhesion, pathogenicity and stress conditions. Even though the biofilm cells in this work were not submitted to any stress condition, some stress related proteins were expressed only in the biofilm condition, suggesting that the biofilm cells would constitutively express proteins in different adverse environments.</p> <p>Conclusions</p> <p>We observed overexpression of proteins related to quorum sensing, proving the existence of communication between cells, and thus the development of structuring the biofilm (mature biofilm) leading to obstruction of vessels and development of disease. This paper reports a first proteomic analysis of mature biofilm of <it>X. fastidiosa</it>, opening new perspectives for understanding the biochemistry of mature biofilm growth in a plant pathogen.</p

The Fourier Imaging X-ray Spectrometer (FIXS) for the Argentinian, Scout-launched satelite de Aplicaciones Cienficas-1 (SAC-1)

The Fourier Imaging X-ray Spectrometer (FIXS) is one of four instruments on SAC-1, the Argentinian satellite being proposed for launch by NASA on a Scout rocket in 1992/3. The FIXS is designed to provide solar flare images at X-ray energies between 5 and 35 keV. Observations will be made on arcsecond size scales and subsecond time scales of the processes that modify the electron spectrum and the thermal distribution in flaring magnetic structures

Deficiência de boro no metabolismo de pontas de raízes de tomateiro

Variations in growth, total soluble sugars, mono and polyphenols, proteins and ribonucleic acids were studied in root tips of tomato (Lycopersicon esculentum Mill. cv. Campbell 33) submitted to boron deficiency for 0, 2, 4, and 6 days. From the second day onwards, boron deficiency reduced growth of the plants and also the concentration of total soluble sugars (a fact probably associated with the increased synthesis of structural material) and monophenols (a phenomenon associated to the increased oxidation of these compounds). Polyphenols, proteins and RNA were increased in the boron-deficient root tips. Boron may act more directly on the ribonucleic acid metabolism than on protein metabolism.Estudaram-se as variações de crescimento, açúcares solúveis totais, mono e polifenóis, proteínas e ácidos ribonucléicos em pontas de raízes de tomateiro (Lycopersicon esculentum Mill. cv. Campbell 33), submetido à deficiência de boro por 0, 2, 4 e 6 dias. A partir do segundo dia, a deficiência de boro reduziu o crescimento das plantas, os teores de açúcares solúveis (fato provavelmente associado à maior síntese de material estrutural) e de monofenóis (associado à maior oxidação desses compostos). Polifenóis, proteínas e ARN sofreram aumentos nas raízes deficientes. Possivelmente o boro tem ação mais direta sobre o metabolismo de ácidos ribonucléicos que de proteínas

Laparoendoscopic single-site (LESS) sacrocolpopexy: feasibility and efficacy of knotless procedure performed with conventional instruments

The aim of this paper was to report a case of a patient with stage IV vaginal vault prolapse treated by laparoendoscopic single-site (LESS) sacrocolpopexy using an Alexis retractor and a surgical glove attached to three trocars through a 3.5-cm umbilical incision. Only conventional laparoscopic instruments were used for intrabdominal dissection of vagina and peritoneum. The mesh was fixed to the vaginal fornix and to the sacral periosteum from the promontory using running sutures hold in the extremities by polymer clips. The posterior peritoneum was closed over the mesh. LESS sacrocolpopexy performed with conventional instruments is a difficult but feasible and efficient technique to treat vaginal vault prolapse that respects the principles of conventional laparoscopic or open repairs. Alexis retractor associated with knotless sutures are technical options that simplify LESS reconstructive surgical maneuvers

PESQUISA NA WEB: ANÁLISE DOS CAMINHOS INVESTIGATIVOS COM MÚLTIPLOS TEXTOS

Com o advento da tecnologia, a sociedade que se configura exige do sujeito letrado conhecimentos mais complexos para enfrentar novas situações, em diversos campos da atuação humana. No âmbito escolar, apesar de contarem com diversos aparatos tecnológicos, o que se tem visto é uma educação com base na transferência de informações, suscitando um trabalho ainda nos moldes tradicionais. Por esse motivo, é viável dizer que o ensino com as tecnologias deve ser ressignificado. Nesse sentido, é crucial que o professor se aproprie de saberes que possibilitem a (re)estruturação em sua prática pedagógica. Sendo assim, pretende-se aqui apresentar um trabalho investigativo, decorrente de pesquisas na Web, envolvendo múltiplos textos, com alunos da EJA, além de análises dos caminhos percorridos pelos aprendizes, ao longo do processo. Intenta-se argumentar sobre a importância da mediação do professor e de um trabalho de ensino sistematizado, em contraposição a um trabalho espontâneo e livre