59 research outputs found
Physiological responses and production of 'Syrah' vines as a function of training systems
Plant architecture and its interaction with agricultural practices and environmental constraints is determinant for grapevine canopy structure, which is related to carbon assimilation, bud fertility and fruit quality. In this context, this study evaluated the performance of field-grown 'Syrah' grapevines conducted by two management systems: Vertical Shoot Position (VSP) or a modified Geneva Double Curtain (GDC), in Pirapora, state of Minas Gerais, Brazil, during the winters of 2007 and 2008. The evaluations of leaf area, water relations and net CO2 assimilation were made at the end of the ripening period. Yield per vine and per hectare were estimated and mean berry weight and diameter, total soluble solids, pH and titratable acidity were evaluated during berry ripening. The grapevines trained in VSP had higher water status as compared to GDC, shown by differences in pre-dawn leaf water potential (ψpd) and stem water potential (ψstem). However, the CO2 assimilation was similar in both training systems. Fruit exposure was higher in VSP than in GDC, which contributed to increasing berry temperature. At harvest, the berries in GDC reached values near to 23 ÂșBrix whereas berries in VSP showed values near 21 ÂșBrix
Genetic algorithm in ab initio protein structure prediction using low resolution model : a review
Proteins are sequences of amino acids bound into a linear chain that adopt a specific folded three-dimensional (3D) shape. This specific folded shape enables proteins to perform specific tasks. The protein structure prediction (PSP) by ab initio or de novo approach is promising amongst various available computational methods and can help to unravel the important relationship between sequence and its corresponding structure. This article presents the ab initio protein structure prediction as a conformational search problem in low resolution model using genetic algorithm. As a review, the essence of twin removal, intelligence in coding, the development and application of domain specific heuristics garnered from the properties of the resulting model and the protein core formation concept discussed are all highly relevant in attempting to secure the best solution
Lawson criterion for ignition exceeded in an inertial fusion experiment
For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37Â MJ of fusion for 1.92Â MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion
Fetal Exposure to Placental Corticotropin-Releasing Hormone is Associated with Child Self-Reported Internalizing Symptoms
Objective Fetal exposure to maternal prenatal stress hormones such as cortisol exerts influences on the developing nervous system that persist and include risk for internalizing symptoms later in life. Placental corticotropin-releasing hormone (pCRH) is a feto-placental stress signal that also shapes fetal neurodevelopment and may be a more direct indicator of the fetal experience than maternal stress hormones. The programming effects of pCRH on child development are unknown. The current investigation examined associations between prenatal maternal and placental stress hormone exposures (maternal cortisol and pCRH) and child self-reported internalizing symptoms at age 5. Method Maternal plasma cortisol and pCRH levels were measured at 15, 19, 25, 31, and 36 weeksâ gestation in a sample of 83 women and their 91 children (8 sibling pairs from separate pregnancies), who were born full-term. Child self-reported internalizing symptoms at age 5 were obtained using scales of the Berkeley Puppet Interview. Results Placental CRH profiles (including elevations in mid-gestation) were associated with higher levels of internalizing symptoms at age 5. This effect was not explained by critical prenatal or postnatal influences, including obstetric risk, concurrent maternal psychological state, and family socio-economic status. Prenatal maternal cortisol was not significantly associated with child self-reported internalizing symptoms. Conclusions Findings suggest that elevated exposures to the feto-placental stress signal pCRH exert programming effects on the developing fetal central nervous system, with lasting consequences for child mental health
A novel technique to prevent bacterial fouling, using imposed surface potential
The effect of modest imposed surface potentials on the adhesion of marine bacteria to an electrically conducting layer deposited on silica glass is recorded. A positive shift increased bacterial settlement. However, a negative shift in potential was extremely beneficial in reducing numbers of adhered bacteria. An applied surface potential of â 66 mV SCE resulted in the bacterial population decreasing to approximately 12% of that on the uncharged reference sample. There was no further significant decrease in the adhered bacterial population when the magnitude of the negative potential was increased. The potential was maintained with very little current flow (less than 0·25 nA mmâ2). The results were not due to any effect of the material used and therefore the technique could be useful for reducing bacterial fouling in many situations, including medical applications
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