light interception efficiency (LIE)

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Does shade improve light interception efficiency? A comparison among seedlings from shade-tolerant and -intolerant temperate deciduous tree species

Does shade improve light interception efficiency? A comparison among seedlings from shade-tolerant and -intolerant temperate deciduous tree species

Irradiance-induced vs ontogenic plasticity of LIE Light interception efficiency was found to vary dramatically in all species with changes in size (leaf area being an estimator of size); that is, there was a large ontogenic plasticity in LIE. A large fraction of the effect of shading on total light inter- ception and LIE was therefore induced by delayed growth in shade vs high light grown saplings (Coleman et al., 1994). Indeed, as leaf area accumulated during growth, leaf overlap severely depressed LIE, as was observed by Farque et al. (2001) in oaks. By contrast, irradiance-induced changes in leaf inclina- tion tended to have a small influence on LIE, owing to the spatial integration over a sky hemisphere where irradiance distribution is essentially homogeneous after light redistribu- tion below the shading nets. This result contradicts some earlier studies that reported a large impact of leaf inclination in the modulation of LIE (Takenaka et al., 2001; Valladares
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Does shade improve light interception efficiency? A comparison among seedling from shade-tolerant and -intolerant temperate deciduous tree species

Does shade improve light interception efficiency? A comparison among seedling from shade-tolerant and -intolerant temperate deciduous tree species

Irradiance-induced vs ontogenic plasticity of LIE Light interception efficiency was found to vary dramatically in all species with changes in size (leaf area being an estimator of size); that is, there was a large ontogenic plasticity in LIE. A large fraction of the effect of shading on total light inter- ception and LIE was therefore induced by delayed growth in shade vs high light grown saplings (Coleman et al., 1994). Indeed, as leaf area accumulated during growth, leaf overlap severely depressed LIE, as was observed by Farque et al. (2001) in oaks. By contrast, irradiance-induced changes in leaf inclina- tion tended to have a small influence on LIE, owing to the spatial integration over a sky hemisphere where irradiance distribution is essentially homogeneous after light redistribu- tion below the shading nets. This result contradicts some earlier studies that reported a large impact of leaf inclination in the modulation of LIE (Takenaka et al., 2001; Valladares
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Influence of the genetic variation of branching during early growth on light interception efficiency of apple trees: a modelling study with MAppleT

Influence of the genetic variation of branching during early growth on light interception efficiency of apple trees: a modelling study with MAppleT

al ., 2011) as well as environmental simulation tools to perform computer-based virtual experiments. Our strategy makes use of MAppleT, i.e. Markov Apple Tree, a FSPM which simulate apple tree topology and geometry for Fuji cultivar (Costes et al., 2008). The light interception of the simulated trees was estimated using MμSLIM, namely Multi-Scale Light Interception Model, included in OpenAlea (Da Silva et al., 2008). This research aims at demonstrating that a sensitivity analysis could be used to investigate the impact of the known genetically variable architectural traits on light interception efficiency. In a previous study, we analysed the impact and interactions of a limited number of geometrical traits on the whole tree light interception (Han et al., 2012). The contribution of the stochastic part of Markov models to the total variance of the output was also examined and was particularly low. Here, we complemented our approach by considering the variation in the trunk first annual shoot branching of the same apple hybrids, and examining the variability induced on light interception, when 5 years old (yo).
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Investigating the Influence of Geometrical Traits on Light Interception Efficiency of Apple Trees: a Modelling Study with MAppleT

Investigating the Influence of Geometrical Traits on Light Interception Efficiency of Apple Trees: a Modelling Study with MAppleT

that has been built for simulating architectural development of apple trees. It has the capability of representing tree growth within a virtual space where the development of individual organs depends on geometrical traits. The purpose of this research is to investigate the influence of apple trees’ architectural variability on their light interception efficiency. The STAR, i.e. the silhouette to total area ratio, of leaves, was chosen to evaluate the level of such efficiency. The strategy is to integrate MAppleT with the light interception model provided by the Fractalysis module of the VPlants software library. Target values of four major traits (internode length, leaf area, branching angle and top shoot diameter), are varied in range previously observed in a segregating population of apple hybrids. A sensitivity analysis based on polynomial and generalized additive models was performed for highlighting the most influential trait on light interception. The contribution of stochastic processes that control tree topology in MAppleT is also investigated in the sensitivity analysis. This study not only provides a time- and resource-saving alternative for data collection, but also sets a methodology for ideotype definition and further genetic improvement of apple trees.
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Influence of the variation of geometrical and topological traits on light interception efficiency of apple trees: sensitivity analysis and metamodelling for ideotype definition

Influence of the variation of geometrical and topological traits on light interception efficiency of apple trees: sensitivity analysis and metamodelling for ideotype definition

year of tree development, generated a large range of tree architec- tures with different TLA and STAR values. The important differ- ence in TLA between the geometry and topology experiments revealed that branching along the first annual shoot of the trunks enhanced tree architecture variability and variance in TLA. The mean values of TLA simulated for 5-year-old trees appeared high in comparison with values obtained on digitized and pruned trees ( Willaume et al., 2004 ). However, this is not surprising if we consider the large range of input values that were used for the simulations. The evolution over the years of the ratio between the mean TLA values for the two experiments seemed reasonable given the fact that the trees in the geometry experiment did not have sylleptic shoots in year 1. However, the outlier individuals in the topology experiment, which again exhibited a TLA 3 – 5 times higher than the mean value, are prob- ably unrealistic model output. Among the reasons that may be involved, the absence of shoot mortality regulation in the MAppleT model is probably a major factor. Indeed, in highly branched young trees, strong competition between shoots may lead to high mortality rates, in particular in the very centre of a very dense canopy. Different factors such as correlation inhib- ition ( Umeki et al., 2006 ), fruiting ( Lampinen et al., 2010 ) and light transmittance ( Takenaka, 2000 ) are likely to be responsible for insufficient shoot growth and a natural mortality. Presently, in the model, mortality rate is constant and is of concern for short shoots only ( Costes et al., 2008 ). As a consequence, all the long and medium shoots are fully grown and therefore participate in both the TLA increase and the STAR reduction.
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Changes in the vertical distribution of leaf area enhanced light interception efficiency in maize over generations of selection

Changes in the vertical distribution of leaf area enhanced light interception efficiency in maize over generations of selection

Summary Breeders select for yield, thereby indirectly selecting for traits that contribute to it. We tested if breeding has affected a range of traits involved in plant architecture and light interception, via the analysis of a panel of 60 maize hybrids released from 1950-2015. This was based on nvel traits calculated from reconstructions derived from a phenotyping platform. The contribution of these traits to light interception was assessed in virtual field canopies composed of 3D plant reconstructions, with a model tested in a real field. Two categories of traits had different contributions to genetic progress. (i) The vertical distribution of leaf area had a high heritability and showed a marked trend over generations of selection. Leaf area tended to be located at lower positions in the canopy, thereby improving light penetration and distribution in the canopy. This potentially increased the carbon availability to ears, via the amount of light absorbed by the intermediate canopy layer, (ii) Neither the horizontal distribution of leaves in the relation to plant rows nor the response of light interception to plant density showed appreciable trends with generations. Hence, among many architectural traits, the vertical distribution of leaf area was the main indirect target of selection.
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Toward a functional-structural model of oil palm : evaluation of genetic differences between progenies for architecture and radiation interception efficiency

Toward a functional-structural model of oil palm : evaluation of genetic differences between progenies for architecture and radiation interception efficiency

R. Perez ¹², J. Dauzat 1 , B. Pallas 2 , H. Rey 1 , G. Le Moguédec ³, 1 4 2 Find more sustainable and productive systems is a major challenge to fulfil increasing vegetable oil demand, including palm oil. Tackling climate changes requires bold and swift ac- tions such as breeding of well suited plant material and implementation of innovative growing practices. But, to this end, we need sound bases of what ideotypes must be for the future and what the proper practices should consist in. For addressing these questions, functional-structural modelling approach (FSPM) enables to explore the relationships between 3D structure of plants with their physiological functioning in relation to weather conditions, with the possibility to simulate virtual management practices such as clearing and pruning. The main assumption underlying this project is the possibility to enhance potential oil palm production optimizing plant architecture in relation to radiation use efficiency. The present study investigates two aspects of a FSPM study applied to oil palm: i) characterize architectural variability and reconstruct three-dimensional (3D) mock-ups of oil palm and ii) esti- mate light interception efficiency of different oil palm progenies from virtual stands.
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Modelling architectural traits of oil palm progenies and their effect on light interception at plant and stand scales

Modelling architectural traits of oil palm progenies and their effect on light interception at plant and stand scales

To this end we developed a model for simulating the 3D architecture of oil palms from morphometric and geometric measurements. Allometric relationships were subsequently designed to simulate the morphogenetic gradients of architectural traits within the crown at leaf and leaflet scales. The methodology allowed reconstructing virtual oil palms at different stages over plant development. Additionally, the allometric-based approach was coupled to mixed model effect in order to integrate inter and intra progeny variability through progeny- specific parameters. The model thus enabled to simulate the specificity of plant architecture for a given progeny while including inter-individual variability. The AMAPstudio software (Griffon & de Coligny, 2014) was used to generate populations of 3D virtual palms for estimating light interception efficiency of 5 progenies, from individual scale to stand scale. A sensitivity analysis was then performed on the architectural parameters to evaluate their impact on light interception efficiency.
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Toward a functional-structural model of oil palm able to assist the evaluation of genetic differences between progenies for architecture and radiation interception efficiency

Toward a functional-structural model of oil palm able to assist the evaluation of genetic differences between progenies for architecture and radiation interception efficiency

R. Perez ¹², J. Dauzat 1 , B. Pallas 2 , H. Rey 1 , G. Le Moguédec ³, 1 4 2 Find more sustainable and productive systems is a major challenge to fulfil increasing vegetable oil demand, including palm oil. Tackling climate changes requires bold and swift ac- tions such as breeding of well suited plant material and implementation of innovative growing practices. But, to this end, we need sound bases of what ideotypes must be for the future and what the proper practices should consist in. For addressing these questions, functional-structural modelling approach (FSPM) enables to explore the relationships between 3D structure of plants with their physiological functioning in relation to weather conditions, with the possibility to simulate virtual management practices such as clearing and pruning. The main assumption underlying this project is the possibility to enhance potential oil palm production optimizing plant architecture in relation to radiation use efficiency. The present study investigates two aspects of a FSPM study applied to oil palm: i) characterize architectural variability and reconstruct three-dimensional (3D) mock-ups of oil palm and ii) esti- mate light interception efficiency of different oil palm progenies from virtual stands.
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The impact of interception losses on the water balance in forested mountains range

The impact of interception losses on the water balance in forested mountains range

Beyond such uncertainty, we felt that it was of interest to give further thought to the hydrologic processes that bring about lower flows under forest cover. Once a higher level of evaporation during the winter period was identified on the forested catchment, and it was ascertained that it could be due only to the involvement of loss by interception, it became easier to understand why the overall increase in runoff that was observed after the cut concerned only minor floods. During the "cévenols" rainfall events, the amount of rain and the depth of runoff can be enormous – and the effects of interception losses become totally unnoticeable. The same cannot be said of a relatively light rainfall event. In that case, the depth of runoff measures only a few millimetres, and can therefore be heavily influenced in terms of relative value by a reduction in the effective rainfall due to interception of part of the rain by the plant cover.
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On the Validation of Web X.509 Certificates by TLS interception products

On the Validation of Web X.509 Certificates by TLS interception products

• W: warn the user about the existence of a problem by showing a warning message and asking him/her to make an accept/refuse decision, • R: refuse the certificate and prohibit access to the web server without any intervention by the user. To easily identify the evolution of TLS interception products’ behaviour compared to 2017, we use the symbol è to show any change in the product’s behavior with regards to a test case scenario. The result on the left side of the arrow represents the result obtained in 2017, and the result on the right side of the arrow represents the result obtained in 2019. In addition, we highlight the results that are not conformant to standards by colouring them in red. The evolution in behaviour of a TLS interpection product is considered as a regression when the table shows a change in the cell from a non-coloured result to a red coloured result (e.g. WèA). The evolution is considered as an improvement when there is change from a red-coloured result to a non-coloured result (e.g A èW).
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On the Mechanics of Flow-Induced Vibration of Soft Corals and Particle Interception

On the Mechanics of Flow-Induced Vibration of Soft Corals and Particle Interception

Therefore, the calculation of the capture efficiency is possible without the knowledge of the initial number of particles, and requires only the length of what we call the capture window. Influence of diameter ratio and Reynolds number The above definitions led to the study of capture from different perspectives. Experimentally, Palmer et al. [101] counted the number of intercepted particles advected by a water flow around a fixed rigid cylinder, and found that the capture efficiency, as defined in (1.17), increases with the diameter ratio and Reynolds number according to the following power law η = 0.224Re 0.718 R 2.08 . (1.19) The majority of the particles were captured at the front side of the cylinder, over an angular extension of ±50°, whereas only 5% of them were found at the rear for high Reynolds numbers. Haugen and Kragset [10] reproduced the numerical version of Palmer et al. experiments. They simulated the flow around a cylinder with The Pencil Code [102] using the immersed boundary method (IBM). They waited until the von Kármán vortex street establishes, then spread the particles from a centred slot of a size of the collector diameter. These particles were spheres undergoing only the hydrodynamic drag
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High-throughput estimation of incident light, light interception and radiation-use efficiency of thousands of plants in a phenotyping platform

High-throughput estimation of incident light, light interception and radiation-use efficiency of thousands of plants in a phenotyping platform

Fig. S1. Pipeline analysis of greenhouse hemispherical images. Fig. S2. Comparison between measured and predicted leaf area and plant biomass. Methods S1. Shiny App for Sun Paths and Light transmission calculation. Table S1. Detailed list of software and packages used in this study.

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Spirophenylacridine‐2,7‐(diphenylphosphineoxide)‐fluorene: A Bipolar Host for High‐Efficiency Single‐Layer Blue Phosphorescent Organic Light‐Emitting Diodes

Spirophenylacridine‐2,7‐(diphenylphosphineoxide)‐fluorene: A Bipolar Host for High‐Efficiency Single‐Layer Blue Phosphorescent Organic Light‐Emitting Diodes

orange, [20-23] green, [17, 19, 21, 23-28] blue [15, 19, 23, 29-32] and white [23, 33] ) are rarely reported in literature. Blue SL-PhOLEDs particularly represent the most difficult challenge to address (due to the high triplet energy level, above 2.6 eV, of blue phosphors) and only very few examples have been reported to date. [15, 19, 23, 29-32] most of them displaying a low EQE below 10%. As far as we are aware, only one example of very high performance is reported to date for blue SL-PhOLEDs (EQE of ca 20%, Von= 3V). [31] It should be precise that the literature also reports other strategies to reach high efficiency SL-PhOLEDs such as a host/co-host combination in the EML. Despite promising, this strategy [34-36] requires several molecules instead of only one in conventional SL-PhOLEDs.
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Light interception characteristics estimated from three-dimensional virtual plants for two apple cultivas and influenced by combinations of rootstocks and tree architecture in loess plateau of China

Light interception characteristics estimated from three-dimensional virtual plants for two apple cultivas and influenced by combinations of rootstocks and tree architecture in loess plateau of China

Light interception characteristics estimated from three-dimensional virtual plants for two apple cultivas and influenced by combinations of rootstocks and tree architecture in loess plat[r]

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Universal Host Materials for Red, Green and Blue High-Efficiency Single-Layer Phosphorescent Organic Light-Emitting Diodes

Universal Host Materials for Red, Green and Blue High-Efficiency Single-Layer Phosphorescent Organic Light-Emitting Diodes

(HOMO= -4.97 eV, LUMO= -2.19 eV, E T = 2.40 eV dispersed in the present hosts, Table 2). Usually, green-emitting SL-PhOLEDs display the highest performances (compare to blue and red) as green phosphors are usually the easiest to host in a PhOLED. The difference in term of performances between the three hosts is less marked than for the red phosphor. Indeed, if the highest performance has been again reached with SPA-2,7-F(POPh 2 ) 2 , the two other host materials also display interesting performances. The lowest efficiency is recorded for SPA-2-FPOPh 2 , which displays a maximal EQE of 10.4%, and corresponding CE of 35.6 cd/A and PE of 32.9 lm/W at 0.02 mA/cm² (Table 3). The performances are increased with SPA-3,6-F(POPh 2 ) 2 as a high maximal EQE of 13.9% and corresponding CE of 52.0 cd/A and PE of 38.9 lm/W (at 0.03 mA/cm²) are recorded. The best performance is finally obtained with SPA-2,7-F(POPh 2 ) 2 as host with a maximal EQE of 16.4%, and corresponding CE of 56.3 cd/A and PE of 53.6 lm/W at 0.04 mA/cm² (Table 3). A maximum luminance of 38970 cd.m -2 at 180 mA/cm 2 is reached, translating a high performance and a good stability at high
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Stochastic multi-object guidance laws for interception and rendezvous problems

Stochastic multi-object guidance laws for interception and rendezvous problems

Stochastic Multi-Object Guidance Laws for Interception and Rendezvous Problems Daniel E. Clark Abstract—This paper considers the problem of guiding an unknown number of controllable interceptors to rendezvous with the same target at the same time. It is assumed that the all of the interceptors and the target are described by linear dynamics with Gaussian noise, though the theory presented does not preclude more general models. This extends the work of Athans to consider a scenario where the number of interceptors is unknown and time-varying. In particular, the focus is on the development of a stochastic multi-object guidance law for simulaneous rendez- vous and interception. The work is presented as an homage to Athans’ original work which was published nearly 50 years ago. Index Terms—linear-quadratic control, guidance, multi-object estimation, point processes, interception.
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Light speed

Light speed

the speed of light, how about leaving the engines on for longer; can we cut the journey time down to something more reasonable? Not really, as we reach speeds close to that of light, roughly 1.1 billion kilometres an hour, we run into the universe’s fundamental speed limit. You cannot travel through space-time faster than light. As Einstein famously showed, the faster you go through space, the slower time goes for you compared with everyone who stays home. If you travel to that nearest star at 99.9% of the speed of light, and you go straight there and then come straight home, your onboard clock will tell you just under ten years have passed. However, you will find when you get home that over 220 years have gone by. Leaving friends and family and returning home eight or nine generations later is not much of an incentive to make the trip. If you go faster it gets worse. Passengers on longer, faster trips could return to find the Earth does not exist any more. Author C.S. Lewis described cosmic distances as “God’s Quarantine Precautions”. Maybe he was not far off the truth.
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A comparison of two common flight interception traps to survey tropical arthropods

A comparison of two common flight interception traps to survey tropical arthropods

Coleoptera Although similar types of WT have been employed before by entomologists, we adapt- ed the design and made it larger than others have used in the past, expanding the width (i.e. interception surface) to at least twice the size of previous models (Hill and Cermak 1997, Bouget et al. 2008). We believe this may have made it even more effective at intercepting the flight path of Coleopterans. Furthermore, one difference between our WT model and other interception traps in general is that with our WT, beetles could be stunned by the window itself (in comparison to the soft cloth or plastic as intercep- tion material, see Springate and Basset 1996, Stork and Grimbacher 2006, Basset et al. 2007), leading to greater captures by WT compared to MT. Heavy beetles (i.e. Scara- baeidae, Cerambycidae, Passalidae etc.) are probably more likely to be stunned by the Plexiglas pane than lighter beetles. While others have noted that the use of heavy and bulky glass could damage some insect wings (Peck and Davis 1980), our model uses flexible and very thin Plexiglas that is less likely to damage insects. Our results strongly suggest that this alternative model of FIT could be an efficient alternative to capture beetles in tropical rainforest.
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Light Cryptography

Light Cryptography

We first define a model of secure computation based on light cryptography. Then we construct several protocols that use this concept for secure computa- tions. We design a protocol to allow participants to determine a common date without revealing any information about their personal agendas. We also pro- pose a maximum protocol that allows users to compute the maximum of their values in a secure way in order to demonstrate that light cryptography can easily solve the famous Yao’s Millionaires’ problem [16], where two millionaires want to know which has more money without revealing how much each has. We propose an extension that also gives the identity of the owner of the maximum. Finally, we propose a protocol to compute the sum of some integers.
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