scholarly journals Calculation of Differential Propagation Constant Determined by Plant Morphology Using Polarimetric Measurement

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Chufeng Hu ◽  
Nanjing Li
Keyword(s):  
Electromagnetic Wave ◽  
Measurement System ◽  
Random Distribution ◽  
Propagation Constant ◽  
Morphological Characteristics ◽  
Plant Morphology ◽  
Structural Features ◽  
Low Frequencies ◽  
Mathematical Relation ◽  
Power Profile

The morphology of vegetation greatly impacts propagation of polarized electromagnetic wave. In order to validate this phenomenon, the mathematical relation between the differential propagation constant of forest vegetation and of its polarized echo is quantitatively derived by using backscattering power profile. The fluctuation of differential propagation constant with frequency is analyzed by combining the morphological characteristics of vegetation. The accurate copolarized data of 3–10 GHz frequency-domain of small trees are obtained by indoor wideband polarimetric measurement system. The results show that morphological characteristics of vegetation at different frequencies can be obtained by the differential propagation constant of polarized electromagnetic wave. At low frequencies, the plants with structural features presented oriented distribution. However, the plants show random distribution of the echoes at higher frequencies, which is mainly from the canopy. The research provides important information to choose the coherence models employed in the parameters retrieval of vegetations.

Electromagnetic Wave Propagation Along a Buried Insulated Wire

1972 ◽  
Vol 50 (20) ◽  
pp. 2402-2409 ◽  
Author(s):  
James R. Wait
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Electromagnetic Wave Propagation ◽  
Propagation Constant ◽  
Numerical Data ◽  
Infinite Medium ◽  
Low Frequencies ◽  
The Earth ◽  
Attenuation Rate ◽  
Coated Wire

Propagation along a thin dielectric coated wire parallel to the interface between two homogeneous half-spaces is considered. The solution accounts for the presence of the interface provided the coating radius is small compared with the distance to the interface. The final results are simplified in form when dealing with long insulated antennas buried in the earth and operating at low frequencies. Some numerical data are provided for a representative set of conditions. It is found that the presence of the air/earth interface will modify the propagation constant; in some cases the attenuation rate may be increased over that for an infinite medium.

Encasement in plant morphology: an integrative approach from genes to organisms

2005 ◽  
Vol 83 (10) ◽  
pp. 1207-1221 ◽  
Author(s):  
Christian Lacroix ◽  
Bernard Jeune ◽  
Denis Barabé
Keyword(s):  
Growth Rate ◽  
Morphological Characteristics ◽  
Plant Morphology ◽  
Integrative Approach ◽  
Structural Level ◽  
Classical Approach ◽  
Developmental Genes ◽  
Qualitative And Quantitative ◽  
New Concepts ◽  
Dynamic Morphology

Recent advances in molecular genetics are prompting developmental plant morphologists to refine the theoretical context of their field. For example, at the level of the action of certain developmental genes, the distinction between recognized structural categories (i.e., stem and leaf) are not obvious. This issue has also been analyzed by morphologists from qualitative and quantitative perspectives and has lead to similar conclusions. Consequently, the classical approach to morphology with a typological view of organ categories is no longer sufficient to explain the set of all possible forms. However, within the context of a dynamic morphology, where processes of development such as growth rate, duration, and distribution are considered, a more encompassing view of the generation of form can be achieved. We therefore propose that classical morphology is a subset of dynamic morphology. The main goal of this paper is to show how new concepts and methods of viewing plant morphology allow us to build a conceptual theoretical framework that may have a predictive value with respect to morphological characteristics as well as molecular properties of organs. The main premise of this commentary, within the context of dynamic morphology, is that the plant consists of an encasement of structures or a nesting of partially similar units. Common developmental processes are in operation at each structural level and variations in the modalities of these processes lead to the development of specific structures. Repeating polymorphic sets (RPS) represent an extension of this perspective on plant development and have the potential to predict the existence of new, perhaps unknown forms. The idea of repeating polymorphic sets can also be extended to outline the activity of specific developmental genes to explain how a wide variety of those genes are interrelated during development to specify form.

Electromagnetic wave propagation in a chiroplasma-filled waveguide

1999 ◽  
Vol 62 (1) ◽  
pp. 87-94 ◽  
Author(s):  
J. GONG
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Cross Section ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Propagation Constant ◽  
Circular Cross Section ◽  
Propagation Characteristics ◽  
Waveguide Modes ◽  
The Family

A dispersion equation is derived for a cylindrical waveguide of circular cross-section partially filled with chiroplasma. The propagation characteristics of electromagnetic waves in the family of waveguide modes are studied. The dispersion curves are given. It is found that the propagation constant changes almost linearly with the chirality admittance for the parameters that we choose, and increases with increasing filled area.

scholarly journals Isolation of infectious, non-fibrillar and oligomeric prions from a genetic prion disease

Brain ◽  
2020 ◽  
Vol 143 (5) ◽  
pp. 1512-1524 ◽  
Author(s):  
Ilaria Vanni ◽  
Laura Pirisinu ◽  
Claudia Acevedo-Morantes ◽  
Razieh Kamali-Jamil ◽  
Vineet Rathod ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Amyloid Fibrils ◽  
Morphological Characteristics ◽  
Immunogold Labelling ◽  
Structural Features ◽  
Cellular Prion Protein ◽  
Proteinase K ◽  
Supernatant Fraction ◽  
C Terminus ◽  
Electron Microscopy Analysis

Abstract Prions are transmissible agents causing lethal neurodegenerative diseases that are composed of aggregates of misfolded cellular prion protein (PrPSc). Despite non-fibrillar oligomers having been proposed as the most infectious prion particles, prions purified from diseased brains usually consist of large and fibrillar PrPSc aggregates, whose protease-resistant core (PrPres) encompasses the whole C-terminus of PrP. In contrast, PrPSc from Gerstmann-Sträussler-Scheinker disease associated with alanine to valine substitution at position 117 (GSS-A117V) is characterized by a small protease-resistant core, which is devoid of the C-terminus. We thus aimed to investigate the role of this unusual PrPSc in terms of infectivity, strain characteristics, and structural features. We found, by titration in bank voles, that the infectivity of GSS-A117V is extremely high (109.3 ID50 U/g) and is resistant to treatment with proteinase K (109.0 ID50 U/g). We then purified the proteinase K-resistant GSS-A117V prions and determined the amount of infectivity and PrPres in the different fractions, alongside the morphological characteristics of purified PrPres aggregates by electron microscopy. Purified pellet fractions from GSS-A117V contained the expected N- and C-terminally cleaved 7 kDa PrPres, although the yield of PrPres was low. We found that this low yield depended on the low density/small size of GSS-A117V PrPres, as it was mainly retained in the last supernatant fraction. All fractions were highly infectious, thus confirming the infectious nature of the 7 kDa PrPres, with infectivity levels that directly correlated with the PrPres amount detected. Finally, electron microscopy analysis of these fractions showed no presence of amyloid fibrils, but only very small and indistinct, non-fibrillar PrPresparticles were detected and confirmed to contain PrP via immunogold labelling. Our study demonstrates that purified aggregates of 7 kDa PrPres, spanning residues ∼90–150, are highly infectious oligomers that encode the biochemical and biological strain features of the original sample. Overall, the autocatalytic behaviour of the prion oligomers reveals their role in the propagation of neurodegeneration in patients with Gerstmann-Sträussler-Scheinker disease and implies that the C-terminus of PrPSc is dispensable for infectivity and strain features for this prion strain, uncovering the central PrP domain as the minimal molecular component able to encode infectious prions. These findings are consistent with the hypothesis that non-fibrillar prion particles are highly efficient propagators of disease and provide new molecular and morphological constraints on the structure of infectious prions.

scholarly journals Study on Morphological and Microscopic Characteristics of Abelmoschus sagittifolius (Kurz) Merr. in Vietnam

2021 ◽  
Vol 37 (2) ◽  
Author(s):  
Pham Thanh Huyen ◽  
Nguyen Quynh Nga ◽  
Pham Thi Ngoc ◽  
Lai Viet Hung ◽  
Phan Van Truong ◽  
...  
Keyword(s):  
Medicinal Plants ◽  
Medicinal Plant ◽  
Publishing House ◽  
Morphological Characteristics ◽  
Plant Morphology ◽  
Botanical Garden ◽  
Gastric Ulcers ◽  
Biological Resources ◽  
Natural Product Research ◽  
Medicinal Powder

Sam bo chinh (Abelmoschus sagittifolius (Kurz) Merr.) is a precious medicinal plant that has been exploited and planted in Vietnam for a long time. However, the morphological characteristics of this plant is easy to confuse with other species of the same genus. In addition, the microscopic characteristics and medicinal powder composition of this medicinal plant have not been comprehensively described. The present investigation was aimed to determine the morphological and microscopic characters of Sam bo chinh using comparative morphology, anatomical research and medicinal powder analysis. The complete description of morphological and microscopic characteristics reported in this study will serve as valuable data for the conservation and development of this species in Vietnam. Keywords Morphology, microscopic characteristics, medicinal plant, Abelmoschus sagittifolius. References [1] The International Plant Names Index and World Checklist of Selected Plant Families 2021, http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:558042-1, (accessed on: 7th May 2021).[2] P. H. Ho, Medicinal Plants in Vietnam, Tre Publishing House, Ho Chi Minh, 2006, pp. 112 (in Vietnamese).[3] D. H. Bich et al., Medicinal Plants and Medicinal Animals in Vietnam, Science and Technics Publishing House, Hanoi, 2006, pp. 690-693 (in Vietnamese).[4] Ministry of Health, Vietnamese Pharmacopoeia V, Medical Publishing House, Hanoi, 2018, pp. 1310-1311 (in Vietnamese).[5] G. L. D. Chen, Y. Y. Liu, G. X. Ma, W. Zheng, X. B. Sun, X. D. Xu, A New Cadinane Sesquiterpenoid Glucoside with Cytotoxicity from Abelmoschus sagittifolius, Natural Product Research, Vol. 33, 2019, pp. 1699-1704, https://doi.org/10.1080/14786419.2018.1431635.[6] D. T. Vui, Study Chemical Composition and Pharmacological Effects towards The Treatment Gastric Ulcers of The Roots of Abelmoschus sagittifolius (Kurz) Merr. Malvaceae, Doctoral Thesis, National Institute of Medicinal Materials, Hanoi, 2007 (in Vietnamese).[7] D. T. Xuyen, Some New Information on The Genus Abelmoschus Medic. in Vietnam, Scientific Report on Ecology and Biological Resources, The First National Conference, Institute of Ecology and Biological Resources, Hanoi, 2005 (in Vietnamese).[8] N. N. Thin, Methods of Plant Research, Vietnam National University Press, Hanoi, 2007 (in Vietnamese).[9] N. Ba, Plant Morphology, Vietnam Education Publishing House, Hanoi, 2006 (in Vietnamese).[10] N. V. Than, Testing Medicinal Herbs by Microscopic Method, Science and Technics Publishing House, Hanoi, 2003 (in Vietnamese).[11] P. H. Raven, H. D. W. Zhengyi, Flora of China, Science Press (Beijing) & Missouri Botanical Garden (St. Louis), China and USA, 2007, pp. 283-285.[12] Abelmoschus moschatus (L.) Medik, http://uphcm.edu.vn/caythuoc/index.php?q=book/export/html/298, (accessed on: May 25th, 2020) (in Vietnamese)

scholarly journals Molecular Markers Associated with Morphological Traits in Watermelon

HortScience ◽  
2001 ◽  
Vol 36 (7) ◽  
pp. 1318-1322 ◽  
Author(s):  
Leigh K. Hawkins ◽  
Fenny Dane ◽  
Thomas L. Kubisiak
Keyword(s):  
Morphological Traits ◽  
Coat Color ◽  
Random Amplified Polymorphic Dna ◽  
Low Frequency ◽  
Morphological Characteristics ◽  
Multiple Allele ◽  
Low Frequencies ◽  
Single Factor Analysis ◽  
Seed Characteristics ◽  
Allele Series

Morphological traits were examined in an F3 generation derived from a cross between C. lanatus var. lanatus [(Thunb.) Matsum. & Nakai] and C. lanatus var. citroides. At least three genes, C (yellow) vs. c (red), i (inhibitory to C) vs. I (non-inhibitory to C), and y (yellow) vs. yw (white), with epistatic and inhibitory actions were found to govern the inheritance of fruit flesh color. The high frequency of yellow-fleshed fruit and low frequencies of white and red fruits can be explained by the presence of a new allele (yw recessive to y) in the multiple allele series at the Y locus. The low frequency of tan colored seeds in segregating populations could be explained by at least three genes governing inheritance of seed-coat color. Single factor analysis of variance was conducted for each pairwise combination of random amplified polymorphic DNA (RAPD) locus and fruit or seed characteristics. Several RAPD loci were identified to be loosely linked to morphological characteristics.

scholarly journals Disaggregation of spatial rainfall fields for hydrological modelling

2001 ◽  
Vol 5 (2) ◽  
pp. 165-173 ◽  
Author(s):  
N. G. Mackay ◽  
R. E. Chandler ◽  
C. Onof ◽  
H. S. Wheater
Keyword(s):  
General Circulation ◽  
Large Scale ◽  
Morphological Characteristics ◽  
Circulation Model ◽  
Structural Features ◽  
Surface Boundary ◽  
Radar Rainfall ◽  
Meteorological Model ◽  
Posterior Probability Distribution ◽  
Temporal Properties

Abstract. Meteorological models generate fields of precipitation and other climatological variables as spatial averages at the scale of the grid used for numerical solution. The grid-scale can be large, particularly for GCMs, and disaggregation is required, for example to generate appropriate spatial-temporal properties of rainfall for coupling with surface-boundary conditions or more general hydrological applications. A method is presented here which considers the generation of the wet areas and the simulation of rainfall intensities separately. For the first task, a nearest-neighbour Markov scheme, based upon a Bayesian technique used in image processing, is implemented so as to preserve the structural features of the observed rainfall. Essentially, the large-scale field and the previously disaggregated field are used as evidence in an iterative procedure which aims at selecting a realisation according to the joint posterior probability distribution. In the second task the morphological characteristics of the field of rainfall intensities are reproduced through a random sampling of intensities according to a beta distribution and their allocation to pixels chosen so that the higher intensities are more likely to be further from the dry areas. The components of the scheme are assessed for Arkansas-Red River basin radar rainfall (hourly averages) by disaggregating from 40 km x 40 km to 8 km x 8 km. The wet/dry scheme provides a good reproduction both of the number of correctly classified pixels and the coverage, while the intensitiy scheme generates fields with an adequate variance within the grid-squares, so that this scheme provides the hydrologist with a useful tool for the downscaling of meteorological model outputs. Keywords: Rainfall, disaggregation, General Circulation Model, Bayesian analysis

Smart proppant concept for monitoring hydraulic fractures

2011 ◽  
Vol 51 (1) ◽  
pp. 527 ◽  
Author(s):  
Arcady Dyskin ◽  
Elena Pasternak ◽  
Greg Sevel ◽  
Rachel Cardell-Oliver
Keyword(s):  
Fluid Flow ◽  
Random Distribution ◽  
Energy Content ◽  
Low Frequency ◽  
Hydraulic Fractures ◽  
Low Frequencies ◽  
Flow Channels ◽  
Monitoring Technique ◽  
Smart Actuators ◽  
Subsurface Fluid

Monitoring subsurface fluid flow is important in mapping hydraulic fractures and identifying flow channels in reservoirs. A new monitoring technique is proposed whereby fluid is injected with smart actuators capable of organising their pulses to create a combined output with a higher proportion of energy at low frequencies. Ideally, the best results occur when actuators are sequentialised so each next actuator emits its pulse immediately after the previous actuator. The low frequency energy content achieved using sequentialisation is much higher than that achieved with a random distribution of pulses, but is relatively insensitive to practical errors in scheduling and irregular attenuations of amplitudes. Simulations show that actuators can be self-organised into a sequential state by monitoring other actuators’ pulses using the algorithm presented in this paper.

Electromagnetic Wave Propagation

2020 ◽  
pp. 78-88
Author(s):  
Magdalene Wan Ching Goh
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Electromagnetic Radiation ◽  
Electromagnetic Wave Propagation ◽  
Propagation Constant ◽  
Characteristic Impedance ◽  
Helmholtz Equations ◽  
Basic Principles ◽  
Atmospheric Windows

Electromagnetic wave propagation is an invisible phenomenon that cannot be detected by the human senses. To understand wave propagation, one must first learn what wave propagation is and the basic principles that affect wave propagation. This chapter introduces the atmospheric windows which allow electromagnetic radiation from bands to penetrate Earth. Helmholtz equations, i.e. the equations which govern wave propagation, and the properties of waves (such as propagation constant and characteristic impedance) are then briefly explained. When waves encounter different media during its propagation, they may be reflected, refracted, or diffracted. These phenomena are also covered. The last part of this chapter concisely explains the terminologies commonly used to describe electromagnetic radiation.

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