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Several Experiments (several + experiment)
Selected AbstractsEstrogenic effect of leachates and soil extracts from lysimeters spiked with sewage sludge and reference endocrine disruptersENVIRONMENTAL TOXICOLOGY, Issue 2 2002Halim Dizer Abstract Several experiments were conducted to evaluate the behavior and performance of some potential endocrine disrupters (ECDs). Two in vitro screening assays, one based on MCF7-cell proliferation (E-screen test) and the other on estrogenic receptor activity [enzyme-linked receptor assay (ELRA)], were used for the tests, which were done in lysimeters 80 cm in diameter with depths of 30 cm (shallow) or 90 cm (deep). A sandy soil was used to fill in all lysimeters, which were spiked on the surface with either: (a) a sewage sludge (SS) at a dose equivalent to 20 tons ha,1; (b) a mixture of reference ECDs, comprising 17,- and 17,-estradiol (E2), nonylphenol, octylphenol, and bisphenol A at doses 100 times higher than the maximum concentrations respectively found in the applied SS; or (c) a mixture of ECDs and SS. After percolation of the lysimeters with rain and/or artificial water, five leachates were sampled from each lysimeter during a period of 210 days. Immediately after the lysimeter percolation experiments, four and six soil fractions were dissected from, respectively, the 30-cm and 90-cm lysimeters and extracted by water. Both the leachate and soil extract samples were analyzed for their estrogenicity using the assays indicated above. The E-screen assay was highly sensitive only for some leachate and extract samples but gave no response for most leachates and soil extracts. The results of the ELRA assay suggests a significantly higher estrogenicity of leachate samples from shallow lysimeters compared with that of leachates from deep lysimeters. In contrast, the estrogenic effect measured for soil extracts of shallow lysimeters was lower than that measured for soil extracts of deep lysimeters. The results of the E-screen assay suggests the occurrence of a fast mobilization of applied ECDs and a moderate retardation effect of native ECDs contained in applied SS in the sandy soil used in the lysimeters. In lysimeters spiked with a mixture of SS and ECDs, the washing-out effect of ECDs in the first leachate fraction decreased, but the distribution of ECDs in the lysimeters increased. The relatively high estrogenic impact measured for soil water extracts suggests that the ECDs were mostly associated with water-soluble fractions of organic matter and/or water-suspended fractions of the mineral soil matrix. The application of SS to agricultural and forest fields may determine the immobilization of ECDs in soil or their movement to surface and/or groundwater. Therefore, an endocrine risk of exposure exists for the water and soil organisms. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 105,112, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10038 [source] Synthesis of Pyrrole Derivatives through Functionalization of 3,4-Bis(lithiomethyl)dihydropyrrolesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2003José Barluenga Abstract Bis(2-lithioallyl)amines 2, substituted at the double bonds, undergo intramolecular carbolithiation of a lithiated double bond in different solvents to afford dilithiated dihydropyrroles 3. Treatment of these dianions with electrophiles allows the preparation of functionalized pyrrole derivatives 5 and 6. Interestingly, treatment of these dianions with carboxylic esters selectively affords either keto or hydroxy compounds (9 or 10), depending on the conditions. Several experiments have been carried out in order to clarify the mechanism of this selective transformation. Finally, dilithiated dihydropyrrole 3a could be transformed in a three-step procedure into the corresponding 3,4-bis(bromomethyl) derivative 31, which can easily be converted into bicyclic pyrrole compounds 32,33 by treatment with different nucleophiles. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Insight into the molecular mechanisms of glucocorticoid receptor action promotes identification of novel ligands with an improved therapeutic indexEXPERIMENTAL DERMATOLOGY, Issue 8 2006Heike Schäcke Abstract:, Glucocorticoids are highly effective in the therapy of inflammatory and autoimmune disorders. Their beneficial action is restricted because of their adverse effects upon prolonged usage. Topical glucocorticoids that act locally have been developed to significantly reduce systemic side effects. Nonetheless, undesirable cutaneous effects such as skin atrophy persist from the use of topical glucocorticoids. There is therefore a high medical need for drugs as effective as glucocorticoids but with a reduced side-effect profile. Glucocorticoids function by binding to and activating the glucocorticoid receptor that positively or negatively regulates the expression of specific genes. Several experiments suggest that the negative regulation of gene expression by the glucocorticoid receptor accounts for its anti-inflammatory action. This occurs through direct or indirect binding of the receptor to transcription factors such as activator protein-1, nuclear factor- ,B or interferon regulatory factor-3 that are already bound to their regulatory sites. The positive action of the receptor occurs through homodimer binding of the receptor to discrete nucleotide sequences and this possibly contributes to some of the adverse effects of the hormone. Glucocorticoid receptor ligands that promote the negative regulatory action of the receptor with reduced positive regulatory function should therefore show improved therapeutic potential. A complete separation of the positive from the negative regulatory activities of the receptor has so far not been possible because of the interdependent nature of the two regulatory processes. Nevertheless, considerable improvement in the therapeutic action of glucocorticoid receptor ligands is being achieved through the use of key molecular targets for screening novel glucocorticoid receptor ligands. [source] Text binarization in color documentsINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 6 2006Efthimios Badekas Abstract This article presents a new method for the binarization of color document images. Initially, the colors of the document image are reduced to a small number using a new color reduction technique. Specifically, this technique estimates the dominant colors and then assigns the original image colors to them in order that the background and text components to become uniform. Each dominant color defines a color plane in which the connected components (CCs) are extracted. Next, in each color plane a CC filtering procedure is applied which is followed by a grouping procedure. At the end of this stage, blocks of CCs are constructed which are next redefined by obtaining the direction of connection (DOC) property for each CC. Using the DOC property, the blocks of CCs are classified as text or nontext. The identified text blocks are binarized properly using suitable binarization techniques, considering the rest of the pixels as background. The final result is a binary image which contains always black characters in white background independently of the original colors of each text block. The proposed document binarization approach can also be used for binarization of noisy color (or gray-scale) document images. Several experiments that confirm the effectiveness of the proposed technique are presented. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 16, 262,274, 2006 [source] Expression of a releasable form of annexin II by human keratinocytesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 4 2002Feridoun Karimi-Busheri Abstract Annexin II is a multifunctional calcium-dependent phospholipid binding protein whose presence in epidermis has previously been reported. However, like other members of annexin family, annexin II has been regarded as either an intracellular protein or associated with the cellular membrane. Here, we report the presence of a releasable annexin II and p11, two monomers of annexin II tetramer, in keratinocyte-conditioned medium (KCM). Proteins present in KCM were fractionated on a gel filtration column and following further evaluation, a releasable protein with apparent MW of 36 kDa was identified. Further characterization identified this protein as the p36 monomer of annexin II tetramer. The phospho-tyrosine antibody did not visualize this protein as the phosphorylated form of p36. Several experiments were conducted to examine whether this protein is soluble or associated with keratinocyte cell membranes in the conditioned medium. A centrifugation of conditioned medium was not able to bring this protein down into the pellet. Surprisingly, the results of Western analysis identified p36 and p11, two monomers of the annexin II tetramer, in conditioned medium derived from either keratinocytes cultured alone or keratinocytes co-cultured with fibroblasts. In contrast to the keratinocyte-conditioned medium in which annexin II was easily detectable, both monomers were barely detectable in conditioned medium collected from dermal fibroblasts. This finding was in contrast to the cell lysates in which p36 was detectable in both keratinocytes and fibroblasts. However, the amount of this protein was markedly higher in keratinocyte lysate relative to that of dermal fibroblasts. Conditioned medium derived from keratinocyte established from adult showed a higher level of annexin II compared to that of keratinocytes established from newborn babies. The expression of p11 seems to increase with differentiation of keratinocytes derived from either adult or newborn skin samples. When the site of annexin synthesis in human skin was examined by immunohistochemical staining, the antibody for p36 localized the annexin to the keratinocyte cell members in the basal and suprabasal keratinocytes. In conclusion, Western blot detection of both p36 and p11 in conditioned medium from skin cells revealed that human keratinocytes, but not fibroblasts, express a releasable monomer form of annexin II which is regulated by differentiation status of keratinocytes. This finding is consistent with the localization of annexin II detected by immunohistochemical staining. J. Cell. Biochem. 86: 737,747, 2002. © 2002 Wiley-Liss, Inc. [source] A cross-coupling controller using an H, scheme and its application to a two-axis direct-drive robotJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 10 2002Ren-Wu Fang A cross-coupling controller (CCC) using an H, control scheme has been proposed to reduce the contouring error for a two-axis, direct-drive robot in tracking linear and circular contours effectively. Under the consideration that contour-tracking performance is a primary target over point-to-point tracking performance in a trajectory-tracking task, a CCC has been associated with joint controllers to reduce the contouring error by coordinating the motion of a two-axis robot arm. Contouring performance can thus be improved significantly. Furthermore, the proposed CCC design, which is a typical Multi-Input Multi-Output (MIMO) system with linear time varying (LTV) characteristics, has been verified as being internally stable. A USM (ultrasonic motor)-driven, two-axis, direct-drive robot is utilized to demonstrate the feasibility of the proposed scheme. Several experiments under various operating conditions are performed to validate its efficacy, and the results showed that the proposed scheme can reduce the contouring error significantly. © 2002 Wiley Periodicals, Inc. [source] Autism: tactile perception and emotionJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 8 2007E. Pernon Abstract Background For many years, and especially since Waynbaum and Wallon, psychology and psychopathology have dealt with cognitive perception, but have had little to do with the affective qualities of perception. Our aim was to study the influence of the sensory environment on people with autism. Method Several experiments were carried out using different forms of tactile stimulation (passive and active subjects). Results Our data showed specific responses in children with autism and intellectual disability. These children displayed a strong (positive) valence to the stimulation provided. Conclusion They were very attracted to the stimulation and were excited by it. [source] Biology of suckers: late-formed shoots in sugarcaneANNALS OF APPLIED BIOLOGY, Issue 1 2001G D BONNETT Summary Suckers in sugarcane are tillers that form late in the growing season after the population of main stalks has been established. Their biology has rarely been studied, though unsubstantiated comments relating to their morphology, development and number are abundant. In this paper, the literature is reviewed and new experiments presented. Comparison of suckers, emerging plant and ratoon cane showed that suckers have a different leaf and stem morphology. Suckers have a greater diameter at their stem base and shorter and wider leaves than primary stalks of a similar age. In 1 -year-old crops, suckers have been demonstrated to decrease the net sucrose concentration of harvested material by diluting sucrose in the main stalks. By comparing main stalks without suckers to those that have initiated suckers, evidence is presented that suckers may also be decreasing the sucrose content of the stalks from which they are growing. Genotypic and environmental factors influence sucker number. Several experiments were designed to identify environmental stimuli for suckering. Increased nitrogen, through application late in the growing season, was found to increase the numbers of suckers present. Manipulation of the light environment of main stalks showed that a change in light quality (but not necessarily quantity) stimulated suckering. Further work is underway to define how these environmental stimuli lead to sucker initiation and growth. Major scientific questions that should be addressed are: the identification of other potential environmental stimuli, how the signals are perceived and translated into sucker initiation, and why suckers have different morphology. The practical challenge is to combine the new information about sucker biology and develop from it strategies to alter agronomy and select new cultivars that results in decreased suckering. [source] Robust face tracking control of a mobile robot using self-tuning Kalman filter and echo state network,ASIAN JOURNAL OF CONTROL, Issue 4 2010Chi-Yi Tsai Abstract This paper presents a novel design of face tracking algorithm and visual state estimation for a mobile robot face tracking interaction control system. The advantage of this design is that it can track a user's face under several external uncertainties and estimate the system state without the knowledge about target's 3D motion-model information. This feature is helpful for the development of a real-time visual tracking control system. In order to overcome the change in skin color due to light variation, a real-time face tracking algorithm is proposed based on an adaptive skin color search method. Moreover, in order to increase the robustness against colored observation noise, a new visual state estimator is designed by combining a Kalman filter with an echo state network-based self-tuning algorithm. The performance of this estimator design has been evaluated using computer simulation. Several experiments on a mobile robot validate the proposed control system. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] A role for genetic accommodation in evolution?BIOESSAYS, Issue 9 2006Christian Braendle Whether evolutionary change can occur by genetic assimilation, or more generally by genetic accommodation, remains controversial. Here we examine some of the experimental evidence for both phenomena. Several experiments in Drosophila suggest that assimilation is possible, and a new paper1 shows that a color polyphenism in the tobacco hornworm, Manduca sexta, can evolve by genetic accommodation. We argue that genetic accommodation, including assimilation, is a plausible mechanism in evolution; however, more work is required to test how this mechanism acts and how often it is involved in evolutionary change. BioEssays 28: 868,873, 2006. © 2006 Wiley periodicals, Inc. [source] Multiple path-based approach to image-based street walkthroughCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 2 2005Dong Hoon Lee Abstract Image-based rendering for walkthrough in the virtual environment has many advantages should over the geometry-based approach, due to the fast construction of the environment and photo-realistic rendered results. In image-based rendering technique, rays from a set of input images are collected and a novel view image is rendered by the resampling of the stored rays. Current such techniques, however, are limited to a closed capture space. In this paper, we propose a multiple path-based capture configuration that can handle a large-scale scene and a disparity-based warping method for novel view generation. To acquire the disparity image, we segment the input image into vertical slit segments using a robust and inexpensive way of detecting vertical depth discontinuity. The depth slit segments, instead of depth pixels, reduce the processing time for novel view generation. We also discuss a dynamic cache strategy that supports real-time walkthroughs in large and complex street environments. The efficiency of the proposed method is demonstrated with several experiments. Copyright © 2005 John Wiley & Sons, Ltd. [source] SCALEA: a performance analysis tool for parallel programsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 11-12 2003Hong-Linh Truong Abstract Many existing performance analysis tools lack the flexibility to control instrumentation and performance measurement for code regions and performance metrics of interest. Performance analysis is commonly restricted to single experiments. In this paper we present SCALEA, which is a performance instrumentation, measurement, analysis, and visualization tool for parallel programs that supports post-mortem performance analysis. SCALEA currently focuses on performance analysis for OpenMP, MPI, HPF, and mixed parallel programs. It computes a variety of performance metrics based on a novel classification of overhead. SCALEA also supports multi-experiment performance analysis that allows one to compare and to evaluate the performance outcome of several experiments. A highly flexible instrumentation and measurement system is provided which can be controlled by command-line options and program directives. SCALEA can be interfaced by external tools through the provision of a full Fortran90 OpenMP/MPI/HPF frontend that allows one to instrument an abstract syntax tree at a very high-level with C-function calls and to generate source code. A graphical user interface is provided to view a large variety of performance metrics at the level of arbitrary code regions, threads, processes, and computational nodes for single- and multi-experiment performance analysis. Copyright © 2003 John Wiley & Sons, Ltd. [source] Functional regeneration of the olfactory bulb requires reconnection to the olfactory nerve in Xenopus larvaeDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 1 2006Jun Yoshino Larvae of the South African clawed frog (Xenopus laevis) can regenerate the telencephalon, which consists of the olfactory bulb and the cerebrum, after it has been partially removed. Some authors have argued that the telencephalon, once removed, must be reconnected to the olfactory nerve in order to regenerate. However, considerable regeneration has been observed before reconnection. Therefore, we have conducted several experiments to learn whether or not reconnection is a prerequisite for regeneration. We found that the olfactory bulb did not regenerate without reconnection, while the cerebrum regenerated by itself. On the other hand, when the brain was reconnected by the olfactory nerve, both the cerebrum and the olfactory bulb regenerated. Morphological and histological investigation showed that the regenerated telencephalon was identical to the intact one in morphology, types and distributions of cells, and connections between neurons. Froglets with a regenerated telencephalon also recovered olfaction, the primary function of the frog telencephalon. These results suggest that the Xenopus larva requires reconnection of the regenerating brain to the olfactory nerve in order to regenerate the olfactory bulb, and thus the regenerated brain functions, in order to process olfactory information. [source] Coupled damage and plasticity modelling in transient dynamic analysis of concreteINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 1 2002Fabrice Gatuingt Abstract In a concrete structure subjected to an explosion, for example a concrete slab, the material is subjected to various states of stress which lead to many modes of rupture. Closer to the explosive, a state of strong hydrostatic compression is observed. This state of stress produces an irreversible compaction of the material. Away from the zone of explosion, confinement decreases and the material undergoes compression with a state of stress, which is slightly triaxial. Finally, the compression wave can be reflected on a free surface and becomes a tensile wave, which by interaction with the compression wave, produces scabbing. We present, in this paper, a model aimed at describing these three failure modes. It is based on visco-plasticity and rate dependent damage in which a homogenization method is used in order to include the variation of the material porosity due to compaction. The model predictions are compared with several experiments performed on the same concrete. Computations of split Hopkinson tests on confined concrete, a tensile test with scabbing, and an explosion on a concrete slab are presented. Copyright © 2001 John Wiley & Sons, Ltd. [source] Hybrid Inorganic-Organic Materials Carrying Tertiary Amine and Thiourea Residues Tethered on Mesoporous Silica Nanoparticles: Synthesis, Characterization, and Co-Operative CatalysisADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009Alessandra Puglisi Abstract Mesoporous silica nanoparticles carrying different loadings of tertiary amine and thiourea residues (residues ratios 53/47, 68/32, and 22/78, respectively) were synthesized by the co-condensation method and fully characterized by CP MAS NMR, powder XRD, SEM, BET, BJH and FT-IR techniques. These materials were tested as bifunctional catalysts in the conjugate addition of acetylacetone to 2-nitrostyrene, a reaction that under solvent-free conditions occurred in quantitative yield. By carrying out several experiments with the bifunctional catalysts featuring different molar ratios of active sites, and with different combinations of monofunctional supported and non-supported catalyst, the co-operativity of the tertiary amine and thiourea residues in catalyzing the reaction was demonstrated. The use of the bifunctional catalyst was extended to the addition of acetylacetone to an activated imine. Catalyst recycling for a total of three reaction cycles was demonstrated without significant erosion of activity. [source] ANTIOXIDANT PROPERTIES OF WATER EXTRACTS FROM PARCHING GREEN TEAJOURNAL OF FOOD BIOCHEMISTRY, Issue 3 2010SHENG-DUN LIN ABSTRACT Cold and hot water extracts (2, 6 and 10%) were prepared from parching green tea and its antioxidant properties studied and potential antioxidant components determined. Yields of hot water extracts (17.53,28.63%) were significantly higher than those of cold water extracts (13.34,16.14%). The half maximal effective concentration (EC50) values in antioxidant activity and reducing power were 2.17,2.75 and 0.22,0.30 mg/mL, respectively. Scavenging abilities on 1,1-diphenyl-2-picrylhydrazyl radicals were comparable. EC50 values in scavenging ability on hydroxyl radicals and chelating ability on ferrous ions were 3.31,4.54 and 1.63,3.09 mg/mL, respectively. Contents of total phenols were 220.52,339.83 mg/g whereas those of total catechins in cold and hot water extracts were 130.22,146.28 mg/g and 136.40,191.33 mg/g, respectively. Based on the results obtained, hot water extracts were more effective in antioxidant activity, reducing power and scavenging ability on hydroxyl radicals but less effective in chelating ability on ferrous ions. PRACTICAL APPLICATIONS Tea is one of popular drinks in the world. The consumption of green tea is especially popular in Asia, mainly for its health benefits. Parched tea is a Chinese style green tea, which is different from the Japanese style steamed tea. Recently, the tea prepared by brewing tea leaves in cold water has become a new choice in Taiwan in addition to traditionally hot water-brewed tea. Results from this research, the cold and hot water extracts of green tea are good antioxidant. Besides, green tea is also reported to reduce serum cholesterol levels and inhibit hypertension, mutagenesis, and tumourigenesis in several experiments in vitro and in vivo. Therefore, the extract of green tea has the potential to be developed into new health foods, and the cold brewing would be a new alternative way to make a tea. [source] A New Simple Neurophysiological Method (Through Conventional Electrical Stimulation) To Assess Function Of Tactile Receptors And Related Nerve FibersJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2001L Padua Sometimes standard sensory nerve conduction studies show normal results in patients with definite symptoms of sensory polyneuropathy. This is usually explained because standard neurophysiological tests evaluate only large myelinated fibers and do not assess the slowest conducting fibers, more distal segments of the nerves and tactile receptors. Tactile stimulation is a test, not routinely available, that assesses the function of tactile receptors and conduction of fibers that are depolarized by these receptors. During conventional sensory nerve conduction studies (in patients and healthy subjects) through surface electrodes, where we slowly increased the intensity of the stimulus, we occasionally observed a sensory response characterized by a particular morphology with two peaks. After several experiments (performed in the neurophysiological laboratories of Catholic University of Rome and of University of Uppsala) we argued that the double component of the response is the expression of the stimulation of tactile receptors (and depolarization of their related fibers). Therefore an electrical stimulation through conventional EMG equipment allows us to assess function of tactile receptors (and related nerve fibers). This observation may have important diagnostic application in clinical practice to evaluate suspected polyneuropathies negative to neurophysiological conduction studies. [source] Production of luteolin extracts from Reseda luteola and assessment of their dyeing propertiesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2002Alfonso Cerrato Abstract In this work, several experiments were performed sequentially in 50,cm3 shaken tubes and a 1,dm3 stirred extractor, thus allowing methanol to be selected as the most appropriate leaching solvent for luteolin from leaves, stems and flowers of weld (Reseda luteola). The extraction capability of methanol at 25,°C was found to be about 7 times greater than that of boiling water at pH 10. A composite design experiment allowed the effects of particle size and liquid/solid ratio to be determined, thus resulting in an optimal luteolin extraction yield of 8.6,±,0.2,g,kg,1 dried weld material when leaching plant particles sieved through 0.5,mm openings with 40,dm3 methanol kg,1. Preliminary dyeing tests on pre-mordanted raw cotton and wool standard specimens gave rise to dyed specimens with the same greenish-yellow hue but greater or smaller values of lightness and chroma respectively. Despite all dyed specimens exhibiting a minimum resistance to a simulated acid perspiration solution, the resistance to fading of dyed wool specimens was generally greater than that of cotton ones. © 2002 Society of Chemical Industry [source] High-stress plasticity and the core structures of dislocations in siliconPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2007J. Rabier Abstract The recent observation of perfect dislocations at high stress and low temperature in silicon [J. Rabier, P. Cordier, J. L. Demenet, and H. Garem, Mater. Sci. Eng. A 309/310, 74 (2001)] in accordance with the calculations of Duesbery and Joos [M. S. Duesbery and B. Joos, Philos. Mag. A 74, 253 (1996)] has solved the apparent paradox regarding the nature of mobile dislocations in silicon under usual deformation conditions. However, although several experiments and calculations are consistent with those perfect dislocations being located in the shuffle set, little is known about the actual core structure of those dislocations which lie along unusual Peierls valleys: ,112,/30°, ,123,/41°. This paper aims to review and discuss recent results related to high-stress plasticity and dislocation core structure in silicon. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effects of supplementary pollination on cropping success and fruit quality in pistachioPLANT BREEDING, Issue 5 2002Y. Vaknin Abstract The effects of pollen supplementation in pistachio orchards using an electrostatic pollination device were investigated in a 3-year study (1996-98) in San Joaquin Valley, California, USA. Both yield and fruit quality (per cent split fruit) were tested in several experiments. Applying smaller amounts of pollen (1.5 g per tree in early application only in 1996 or 0.5 g in two applications in 1997) resulted in higher yields than with open pollination or supplementary pollination using larger amounts of pollen (1.5 g per tree in four applications in 1996 or 1.0 g in two applications in 1997). Applying 1.0 g pollen in two applications in 1998 resulted in decreased yields compared with open pollination or non-electrostatic pollination. Pollen germinability on the stigma was greatest for open pollination suggesting that overloading the stigmas with pollen in supplementary pollination may not only reduce yield but also increase competition between pollen grains. The per cent split fruit significantly increased only once in 1996. When pollination is a limiting factor, electrostatic pollination of pistachio can increase yield and may even increase fruit quality. However, when pollination is not a limiting factor, electrostatic pollination may even reduce yield. [source] Properties and first application of an error-statistics tuning method in variational assimilationTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 601 2004Bernard Chapnik Abstract The method for tuning observational or background error statistics is presented and some of its properties are exposed using theoretical considerations and experiments carried out in a simplified framework. In particular, the method is shown to be equivalent to a maximum-likelihood evaluation and its efficiency is seen to depend on the number of observations. The results of several experiments carried out with the variational assimilation system of the French numerical weather-prediction system ARPEGE, both with simulated and actual datasets involving satellite radiances, are also presented. The temporal stability of the results and their consistency with the known quality of the measurements are shown. Copyright © 2004 Royal Meteorological Society [source] | |||||||||||||||||||||||||