Alternative soilless media for growing Petunia×hybrida and Impatiens wallerana: Physical behavior, effect of fertilization and nitrate losses

2008 ◽  
Vol 99 (17) ◽  
pp. 8082-8087 ◽  
Author(s):  
Walter Chavez ◽  
Adalberto Di Benedetto ◽  
Gabriela Civeira ◽  
Raúl Lavado
Keyword(s):  
Petunia Hybrida ◽  
Physical Behavior ◽  
Soilless Media ◽  
Nitrate Losses ◽  
Impatiens Wallerana

scholarly journals Dibutylurea Reduces Photosynthesis, Growth, and Flowering of Petunia and Impatiens

1997 ◽  
Vol 122 (4) ◽  
pp. 536-541 ◽  
Author(s):  
Marc W. van Iersel ◽  
Bruce Bugbee
Keyword(s):  
Relative Humidity ◽  
Plant Species ◽  
Petunia Hybrida ◽  
Breakdown Product ◽  
Equivalent Amount ◽  
Flower Number ◽  
Bedding Plant ◽  
Impatiens Wallerana

Dibutylurea (DBU), a breakdown product of benomyl, may be partially responsible for the previously reported phytotoxicity of the fungicide Benlate DF. We quantified the effect of DBU on the growth of two popular bedding plant species, petunia (Petunia × hybrida) and impatiens (Impatiens wallerana Hook. f.). DBU reduced photosynthesis of both species, and its effect strongly depended on the amount of DBU applied. The effects of DBU were most apparent 2 to 4 days after treatment, at which time 1.20 g·m-2 (corresponding to 10% DBU in Benlate DF at maximum labeled drench rate) inhibited photosynthesis completely. DBU also decreased flower number and caused marginal necrosis. DBU effects were more pronounced in low relative humidity. Benlate DF containing 3.1% DBU and an equivalent amount of reagent grade DBU had similar effects on photosynthesis and petunia necrosis. Our results showed that DBU is responsible for at least part of the phytotoxic symptoms that can be caused by Benlate DF. However, other ingredients or breakdown products may also contribute to the phytotoxic symptoms of Benlate DF.

Nanomechanical Characterization in the FIB

2005 ◽  
Author(s):  
Thomas M. Moore
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Materials Characterization ◽  
Depth Of Focus ◽  
Ion Milling ◽  
Nano Technology ◽  
Physical Behavior ◽  
Nanomechanical Testing ◽  
Load Cells ◽  
Scanning Electron

Abstract The availability of the focused ion beam (FIB) microscope with its excellent imaging resolution, depth of focus and ion milling capability has made it an appealing platform for materials characterization at the sub-micron, or "nano" level. This article focuses on nanomechanical characterization in the FIB, which is an extension of the FIB capabilities into the realm of nano-technology. It presents examples that demonstrate the power and flexibility of nanomechanical testing in the FIB or scanning electron microscope with a probe shaft that includes a built-in strain gauge. Loads that range from grams to micrograms are achievable. Calibration is limited only by the availability of calibrated load cells in the smallest load ranges. Deflections in the range of a few nanometers range can be accurately applied. Simultaneous electrical, mechanical, and visual data can be combined to provide a revealing study of physical behavior of complex and dynamic nanostructures.

LEARNING NAIVE PHYSICS BY VISUAL OBSERVATION: USING QUALITATIVE SPATIAL REPRESENTATIONS AND PROBABILISTIC REASONING

2001 ◽  
Vol 01 (03) ◽  
pp. 273-285 ◽  
Author(s):  
PAUL A. BOXER
Keyword(s):  
Bayesian Network ◽  
Probabilistic Reasoning ◽  
Autonomous Robots ◽  
Visual Observation ◽  
Spatial Representations ◽  
Physical Behavior ◽  
Naive Physics ◽  
Action At A Distance ◽  
General Physical ◽  
Test Scenarios

Autonomous robots are unsuccessful at operating in complex, unconstrained environments. They lack the ability to learn about the physical behavior of different objects through the use of vision. We combine Bayesian networks and qualitative spatial representation to learn general physical behavior by visual observation. We input training scenarios that allow the system to observe and learn normal physical behavior. The position and velocity of the visible objects are represented as qualitative states. Transitions between these states over time are entered as evidence into a Bayesian network. The network provides probabilities of future transitions to produce predictions of future physical behavior. We use test scenarios to determine how well the approach discriminates between normal and abnormal physical behavior and actively predicts future behavior. We examine the ability of the system to learn three naive physical concepts, "no action at a distance", "solidity" and "movement on continuous paths". We conclude that the combination of qualitative spatial representations and Bayesian network techniques is capable of learning these three rules of naive physics.

Natural abundances of 15N and 13C indicating physiological responses in Petunia hybrida to infection by longidorid nematodes and nepoviruses

Nematology ◽  
1999 ◽  
Vol 1 (3) ◽  
pp. 315-320 ◽  
Author(s):  
Roy Neilson ◽  
Linda L. Handley ◽  
David Robinson ◽  
Charlie M. Scrimgeour ◽  
Derek J.F. Brown
Keyword(s):  
Nitric Oxide ◽  
Virus Infection ◽  
Petunia Hybrida ◽  
Physiological Responses ◽  
Pr Proteins ◽  
Pathogen Infection ◽  
Infection Virale ◽  
Longidorus Elongatus ◽  
And Control ◽  
Xiphinema Diversicaudatum

Abstract The effects of a) systemic virus infection (arabis mosaic and tomato black ring nepoviruses), b) ectoparasitic nematode feeding (Xiphinema diversicaudatum and Longidorus elongatus) and c) a combination of virus infection and nematode feeding on the natural abundances of 13C(delta13C) and 15N(delta15N) of nitrogen-starved Petunia hybrida were studied. Pathogen-induced effects were not confined to sites of virus infection or nematode feeding. Those treatments with nematodes feeding on Petunia hosts and those with a combination of virus infection and nematode feeding resulted in a depletion of shoot and root 15N compared with controls. Virus-infected plants were more 15N-enriched than those fed upon by nematodes which, in turn, were more 15N-enriched than those with both nematode and virus in combination. Shoot delta13C values from infected treatments were not significantly different from controls. Although root delta13C was significantly different from controls in most treatments, absolute differences were small. Differences in delta15N between infected and control plants were probably caused by physiological responses to pathogen infection/feeding such as production of PR-proteins and/or release of nitric oxide. Le contenu naturel en 15N et 13C comme indicateur de la reaction de Petunia hybrida a l'infestation par les nematodes Longidorides et les nepovirus - La presente etude a porte sur l'influence i) d'une infection virale systemique (nepovirus de la mosaique Arabis et du cercle noir de la tomate), ii) d'une atteinte par des nematodes ectoparasites (Xiphinema diversicaudatum et Longidorus elongatus) et iii) d'une combinaison de deux types de pathogenes sur le contenu naturel en 13C(delta13C) et en 15N(delta15N) de Petunia hybrida deficients en azote. Les effets induits par ces organismes pathogenes ne sont pas limites aux sites de l'infection virale ou a ceux des attaques des nematodes. Compares aux temoins, les traitements comportant les seules attaques de nematodes et ceux comportant des attaques combinees des deux types de parasites provoquent une diminution du 15N des racines et des parties aeriennes. Les plants infectes par les virus avaient un taux en 15N plus eleve que ceux attaques par les nematodes, lesquels, en revanche, contenaient plus de 15N que les plants soumis simultanement aux deux types de parasites. Les taux de delta13C dans les parties aeriennes des plants soumis aux differentes attaques n'etaient pas significativement differents de ceux des temoins. Si, dans la plupart des traitements, les taux de delta13C dans les racines etaient significativement differents de ceux des temoins, ces differences restaient faibles en valeur absolue. Les differences dans les taux en delta15N entre plants infectes et temoins sont probablement la resultante de reactions physiologiques aux pathogenes, telles la production de proteines PR ou l'emission d'oxyde nitrique.

scholarly journals Site‐specific nitrogen balances based on spatially variable soil and plant properties

2021 ◽  
Author(s):  
Martin Mittermayer ◽  
August Gilg ◽  
Franz-Xaver Maidl ◽  
Ludwig Nätscher ◽  
Kurt-Jürgen Hülsbergen
Keyword(s):  
Soil Properties ◽  
N Uptake ◽  
Nitrate Content ◽  
Site Specific ◽  
Nitrate Losses ◽  
Wide Range ◽  
Reduction Strategies ◽  
Combine Harvester ◽  
Digital Methods ◽  
Collection Methods

AbstractIn this study, site-specific N balances were calculated for a 13.1 ha heterogeneous field. Yields and N uptake as input data for N balances were determined with data from a combine harvester, reflectance measurements from satellites and tractor-mounted sensors. The correlations between the measured grain yields and yields determined by digital methods were moderate. The calculated values for the N surpluses had a wide range within the field. Nitrogen surpluses were calculated from − 76.4 to 91.3 kg ha−1, with a mean of 24.0 kg ha−1. The use of different data sources and data collection methods had an impact on the results of N balancing. The results show the need for further optimization and improvement in the accuracy of digital methods. The factors influencing N uptake and N surplus were determined by analysing soil properties of georeferenced soil samples. Soil properties showed considerable spatial variation within the field. Soil organic carbon correlated very strongly with total nitrogen content (r = 0.97), moderately with N uptake (sensor, r = 0.60) and negatively with N surplus (satellite, r = − 0.46; sensor, r = − 0.56; harvester, r = − 0.60). Nitrate content was analysed in soil cores (0 to 9 m) taken in different yield zones, and compared with the calculated N surplus; there was a strong correlation between the measured nitrate content and calculated N surplus (r = 0.82). Site-specific N balancing can contribute to a more precise identification of the risk of nitrate losses and the development of targeted nitrate reduction strategies.

scholarly journals Symmetry Based Material Optimization

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 315
Author(s):  
Zeyun Shi ◽  
Jinkeng Lin ◽  
Jiong Chen ◽  
Yao Jin ◽  
Jin Huang
Keyword(s):  
Force Field ◽  
Vector Fields ◽  
General Situation ◽  
Kernel Space ◽  
Dynamic Simulations ◽  
Physical Behavior ◽  
Material Parameters ◽  
Material Optimization ◽  
The Asymmetry ◽  
Asymmetric Mesh

Many man-made or natural objects are composed of symmetric parts and possess symmetric physical behavior. Although its shape can exactly follow a symmetry in the designing or modeling stage, its discretized mesh in the analysis stage may be asymmetric because generating a mesh exactly following the symmetry is usually costly. As a consequence, the expected symmetric physical behavior may not be faithfully reproduced due to the asymmetry of the mesh. To solve this problem, we propose to optimize the material parameters of the mesh for static and kinematic symmetry behavior. Specifically, under the situation of static equilibrium, Young’s modulus is properly scaled so that a symmetric force field leads to symmetric displacement. For kinematics, the mass is optimized to reproduce symmetric acceleration under a symmetric force field. To efficiently measure the deviation from symmetry, we formulate a linear operator whose kernel contains all the symmetric vector fields, which helps to characterize the asymmetry error via a simple ℓ2 norm. To make the resulting material suitable for the general situation, the symmetric training force fields are derived from modal analysis in the above kernel space. Results show that our optimized material significantly reduces the asymmetric error on an asymmetric mesh in both static and dynamic simulations.

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