31,665 research outputs found

    Molecular Control of Fruit Ripening and Sensory Quality of Charentais Melon

    Get PDF
    Traditional Charentais melons have a typical climacteric behavior with ethylene playing a major role in the regulation of the ripening process. Genetic studies using climacteric and non-climacteric types of Cucumis melo demonstrated that the climacteric character is dominant and conferred by 2 duplicated loci only which are of great importance for the regulation of storability and sensory quality. Commercial varieties of Charentais melon with long shelf-life have been generated, some of them by crossing with a non-ripening Charentais genotype (Vauclusien). The introduction of the long shelf-life character resulted in undesirable loss of aroma volatiles production. The inhibition of ethylene synthesis by knocking-down ACC oxidase gene expression has been achieved in Charentais melon. It results is a strong inhibition of the synthesis of aroma volatiles while the accumulation of sugars is not affected or is even improved and the softening of the flesh is strongly affected but not abolished. It was also demonstrated that ethylene-inhibited fruit exhibited better resistance to chilling injury. Due to the importance of aroma volatiles in sensory quality and to the strong negative correlation between aroma production and ethylene synthesis, we have developed a research program aimed at isolating genes involved in the synthesis of volatile esters, compounds that are essential for the flavor of Cantaloupe melons. We report here on the recent advances in the field with special emphasis on the characterization of two families of genes encoding aldehyde reductases and alcohol acyl transferases

    Slid Pairs of the Fruit-80 Stream Cipher

    Get PDF
    Fruit is a small-state stream cipher designed for securing communications among resource-constrained devices. The design of Fruit was first known to the public in 2016. It was later improved as Fruit-80 in 2018 and becomes the latest and final version among all versions of the Fruit stream ciphers. In this paper, we analyze the Fruit-80 stream cipher. We found that Fruit-80 generates identical keystreams from certain two distinct pairs of key and IV. Such pair of key and IV pairs is known as a slid pair. Moreover, we discover that when two pairs of key and IV fulfill specific characteristics, they will generate identical keystreams. This shows that slid pairs do not always exist arbitrarily in Fruit-80. We define specific rules which are equivalent to the characteristics. Using the defined rules, we are able to automate the searching process using an MILP solver, which makes searching of the slid pairs trivial

    The wake dynamics and flight forces of the fruit fly Drosophila melanogaster

    Get PDF
    We have used flow visualizations and instantaneous force measurements of tethered fruit flies (Drosophila melanogaster) to study the dynamics of force generation during flight. During each complete stroke cycle, the flies generate one single vortex loop consisting of vorticity shed during the downstroke and ventral flip. This gross pattern of wake structure in Drosophila is similar to those described for hovering birds and some other insects. The wake structure differed from those previously described, however, in that the vortex filaments shed during ventral stroke reversal did not fuse to complete a circular ring, but rather attached temporarily to the body to complete an inverted heart-shaped vortex loop. The attached ventral filaments of the loop subsequently slide along the length of the body and eventually fuse at the tip of the abdomen. We found no evidence for the shedding of wing-tip vorticity during the upstroke, and argue that this is due to an extreme form of the Wagner effect acting at that time. The flow visualizations predicted that maximum flight forces would be generated during the downstroke and ventral reversal, with little or no force generated during the upstroke. The instantaneous force measurements using laser-interferometry verified the periodic nature of force generation. Within each stroke cycle, there was one plateau of high force generation followed by a period of low force, which roughly correlated with the upstroke and downstroke periods. However, the fluctuations in force lagged behind their expected occurrence within the wing-stroke cycle by approximately 1 ms or one-fifth of the complete stroke cycle. This temporal discrepancy exceeds the range of expected inaccuracies and artifacts in the measurements, and we tentatively discuss the potential retarding effects within the underlying fluid mechanics

    Heartrots in Plantation Hardwoods in Indonesia and Australia

    Get PDF
    Resource /Energy Economics and Policy,

    Immune system function, stress, exercise and nutrition profile can affect pregnancy outcome: Lessons from a Mediterranean cohort

    Get PDF
    This article is made available through the Brunel Open Access Publishing Fund.Pregnancy is associated with major physiological and future psychosocial changes, and maternal adaptation to these changes is crucial for normal foetal development. Psychological stress in pregnancy predicts an earlier birth and lower birth weight. Pregnancy-specific stress contributes directly to preterm delivery. The importance of nutrition and exercise during pregnancy with regard to pregnancy outcome has long been acknowledged. This importance has only been further emphasized by the recent changes in food quality and availability, lifestyle changes and a new understanding of foetal programming's effects on adult outcomes. We hypothesised that for a successful pregnancy certain events at a nutritional, immune, psycho-emotional and genetic level should be tightly linked. Therefore, in this study we followed an ‘integrative’ approach to investigate how maternal stress, nutrition, pregnancy planning and exercise influence pregnancy outcome. A key finding of our study is that there was a significant reduction in the intake of alcohol, caffeine-containing and sugary drinks during pregnancy. However, passive smoking in the household remained unchanged. In terms of immune profile, a significant inverse correlation was noted between difficulty to ‘fight’ an infection and number of colds (r=-0.289, P=0.003) as well as the number of infections (r=-0.446, P<0.0001) during pregnancy. The vast majority of the pregnant women acquired a more sedentary lifestyle in the third trimester. In planned, but not in unplanned, pregnancies stress predicted infant weight, independent of age and body mass index (BMI). Notably, in mothers with negative attitudes towards the pregnancy, those with an unplanned pregnancy gave birth to infants with significantly higher weights than those with planned pregnancies. Collectively these data suggest that there is a higher order of complexity, possibly involving gene-environment interactions that work together to ensure a positive outcome for the mother as well as the foetus

    The killer fly hunger games : target size and speed predict decision to pursuit

    Get PDF
    © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Brain, Behavior and Evolution 86 (2015): 28-27, doi:10.1159/000435944.Predatory animals have evolved to optimally detect their prey using exquisite sensory systems such as vision, olfaction and hearing. It may not be so surprising that vertebrates, with large central nervous systems, excel at predatory behaviors. More striking is the fact that many tiny insects, with their miniscule brains and scaled down nerve cords, are also ferocious, highly successful predators. For predation, it is important to determine whether a prey is suitable before initiating pursuit. This is paramount since pursuing a prey that is too large to capture, subdue or dispatch will generate a substantial metabolic cost (in the form of muscle output) without any chance of metabolic gain (in the form of food). In addition, during all pursuits, the predator breaks its potential camouflage and thus runs the risk of becoming prey itself. Many insects use their eyes to initially detect and subsequently pursue prey. Dragonflies, which are extremely efficient predators, therefore have huge eyes with relatively high spatial resolution that allow efficient prey size estimation before initiating pursuit. However, much smaller insects, such as killer flies, also visualize and successfully pursue prey. This is an impressive behavior since the small size of the killer fly naturally limits the neural capacity and also the spatial resolution provided by the compound eye. Despite this, we here show that killer flies efficiently pursue natural (Drosophila melanogaster) and artificial (beads) prey. The natural pursuits are initiated at a distance of 7.9 ± 2.9 cm, which we show is too far away to allow for distance estimation using binocular disparities. Moreover, we show that rather than estimating absolute prey size prior to launching the attack, as dragonflies do, killer flies attack with high probability when the ratio of the prey's subtended retinal velocity and retinal size is 0.37. We also show that killer flies will respond to a stimulus of an angular size that is smaller than that of the photoreceptor acceptance angle, and that the predatory response is strongly modulated by the metabolic state. Our data thus provide an exciting example of a loosely designed matched filter to Drosophila, but one which will still generate successful pursuits of other suitable prey.This work was funded by the Air Force Office of Scientific Research (FA9550-10-0472 to R.M. Olberg and FA9550-15-1-0188 to P.T. Gonzalez-Bellido and K. Nordström), an Isaac Newton Trust/Wellcome Trust ISSF/University of Cambridge Joint Research Grant to Paloma T. Gonzalez-Bellido, a Biotechnology and Biological Sciences Research Council David Phillips Fellowship (BBSRC, BB/L024667/1) to Trevor J. Wardill, the Swedish Research Council (2012-4740) to Karin Nordström and a Shared Equipment Grant from the School of Biological Sciences (University of Cambridge)

    The Killer Fly Hunger Games: Target Size and Speed Predict Decision to Pursuit.

    Get PDF
    Predatory animals have evolved to optimally detect their prey using exquisite sensory systems such as vision, olfaction and hearing. It may not be so surprising that vertebrates, with large central nervous systems, excel at predatory behaviors. More striking is the fact that many tiny insects, with their miniscule brains and scaled down nerve cords, are also ferocious, highly successful predators. For predation, it is important to determine whether a prey is suitable before initiating pursuit. This is paramount since pursuing a prey that is too large to capture, subdue or dispatch will generate a substantial metabolic cost (in the form of muscle output) without any chance of metabolic gain (in the form of food). In addition, during all pursuits, the predator breaks its potential camouflage and thus runs the risk of becoming prey itself. Many insects use their eyes to initially detect and subsequently pursue prey. Dragonflies, which are extremely efficient predators, therefore have huge eyes with relatively high spatial resolution that allow efficient prey size estimation before initiating pursuit. However, much smaller insects, such as killer flies, also visualize and successfully pursue prey. This is an impressive behavior since the small size of the killer fly naturally limits the neural capacity and also the spatial resolution provided by the compound eye. Despite this, we here show that killer flies efficiently pursue natural (Drosophila melanogaster) and artificial (beads) prey. The natural pursuits are initiated at a distance of 7.9 ± 2.9 cm, which we show is too far away to allow for distance estimation using binocular disparities. Moreover, we show that rather than estimating absolute prey size prior to launching the attack, as dragonflies do, killer flies attack with high probability when the ratio of the prey's subtended retinal velocity and retinal size is 0.37. We also show that killer flies will respond to a stimulus of an angular size that is smaller than that of the photoreceptor acceptance angle, and that the predatory response is strongly modulated by the metabolic state. Our data thus provide an exciting example of a loosely designed matched filter to Drosophila, but one which will still generate successful pursuits of other suitable prey.This work was funded the Air force Office of Scientific Research (FA9550-10-0472 to Prof. Robert Olberg). An Isaac Newton Trust / Wellcome Trust ISSF / University of Cambridge Joint Research Grant to Gonzalez-Bellido. BBSRC TO TREVOR WARDILL The Swedish Research Council (2012-4740) to Nordström and a Shared Equipment Grant from the School of Biological Sciences (U. of Cambridge).This is the final version of the article. It first appeared from Karger via http://dx.doi.org/10.1159/00043594

    Can scalable design of wings for flapping wing micro air vehicle be inspired by natural flyers?

    Get PDF
    Lift production is constantly a great challenge for flapping wing micro air vehicles (MAVs). Designing a workable wing, therefore, plays an essential role. Dimensional analysis is an effective and valuable tool in studying the biomechanics of flyers. In this paper, geometric similarity study is firstly presented. Then, the pw−AR ratio is defined and employed in wing performance estimation before the lumped parameter is induced and utilized in wing design. Comprehensive scaling laws on relation of wing performances for natural flyers are next investigated and developed via statistical analysis before being utilized to examine the wing design. Through geometric similarity study and statistical analysis, the results show that the aspect ratio and lumped parameter are independent on mass, and the lumped parameter is inversely proportional to the aspect ratio. The lumped parameters and aspect ratio of flapping wing MAVs correspond to the range of wing performances of natural flyers. Also, the wing performances of existing flapping wing MAVs are examined and follow the scaling laws. Last, the manufactured wings of the flapping wing MAVs are summarized. Our results will, therefore, provide a simple but powerful guideline for biologists and engineers who study the morphology of natural flyers and design flapping wing MAVs

    Modern and Lightweight Component-based Symmetric Cipher Algorithms: A Review

    Get PDF
    Information security, being one of the corner stones of network and communication technology, has been evolving tremendously to cope with the parallel evolution of network security threats. Hence, cipher algorithms in the core of the information security process have more crucial role to play here, with continuous need for new and unorthodox designs to meet the increasing complexity of the applications environment that keep offering challenges to the current existing cipher algorithms. The aim of this review is to present symmetric cipher main components, the modern and lightweight symmetric cipher algorithms design based on the components that utilized in cipher design, highlighting the effect of each component and the essential component among them, how the modern cipher has modified to lightweight cipher by reducing the number and size of these components, clarify how these components give the strength for symmetric cipher versus asymmetric of cipher. Moreover, a new classification of cryptography algorithms to four categories based on four factors is presented. Finally, some modern and lightweight symmetric cipher algorithms are selected, presented with a comparison between them according to their components by taking into considerations the components impact on security, performance, and resource requirements
    • …
    corecore