Research on the relationship between the fractional coverage of the submerged plant Vallisneria spiralis and observed spectral parameters

2012 ◽  
Vol 185 (7) ◽  
pp. 5401-5409
Author(s):  
Qian Cheng ◽  
Kunqi Wu ◽  
Yan Bai ◽  
Yueming Hu
Keyword(s):  
Submerged Plant ◽  
Spectral Parameters ◽  
Vallisneria Spiralis ◽  
Fractional Coverage ◽  
The Relationship

scholarly journals Snail communities improve submerged macrophytes growth by graze epiphytic algae and phytoplankton in a mesocosm experiment

2021 ◽  
Author(s):  
Tian Lv ◽  
Xin Guan ◽  
Shufeng Fan ◽  
Chunhua Liu
Keyword(s):  
Native Plants ◽  
Submerged Macrophytes ◽  
Mesocosm Experiment ◽  
Snail Species ◽  
Complex Relationship ◽  
Elodea Nuttallii ◽  
Submerged Plant ◽  
Epiphytic Algae ◽  
Complex Architecture ◽  
The Relationship

The relationship between producers (e.g., macrophyte, phytoplankton and epiphytic algae) and snails plays an important role in maintaining the function and stability of the shallow ecosystems. A complex relationship exists among macrophytes, epiphytic algae, phytoplankton and snails. An outdoor mesocosm experiment with two-way factorials was carried out, three species submerged macrophytes (Hydrilla verticillate, Vallisneria natans or one exotic submerged plant Elodea nuttallii) and two grazing treatments (4 snail species present or absent) to elucidate those relationships. The results showed that the snail communities reducing the biomass of phytoplankton and epiphytic algae indirect then enhanced the growth of the submerged macrophytes. The macrophyte with complex architecture supported more snail and epiphytic algae, and snails preferred to feed on native plants. Competition drove snails change the grazing preferences to achieve coexistence, so that led to the assembling of snail communities towards the direction of highest resource utilization.

Empirical σ Molecular Orbital Parameters and their Correlation with Rates of Substitution Reactions in Quadrate Cr(III) and Co(III) Complexes

1971 ◽  
Vol 49 (9) ◽  
pp. 1497-1501 ◽  
Author(s):  
C. H. Langford
Keyword(s):  
Field Theories ◽  
Complete Analysis ◽  
Substitution Reactions ◽  
Spectral Parameters ◽  
Empirical Measures ◽  
Orbital Parameters ◽  
Spectral Bands ◽  
Leaving Group ◽  
The Relationship

Empirical measures of σ bonding involving metal 3d orbitals are derived from Perumareddi's (4) complete analysis of the quartet spectral bands of quadrate complexes in the families Cr(NH3)5Xn+ and Cr(OH2)5Xn+. These are shown to correlate with lability of X in the Cr(III) complexes and in Co(NH3)5Xn+ complexes in a sense indicating that relative reactivity is controlled by variation of ligand metal 3d σ interaction. The relationship between the two Cr(III) series implies that the non-labile ligands can labilize the leaving group in proportion to their σ donor capacities. This observation bears on some well-known difficulties in crystal field theories of reactivity. In evaluating the correlation of spectral parameters with reactivity, the role of solvation in reactivity of Cr(III) and Co(III) complexes is discussed with emphasis on the surprisingly small solvent effects that have been observed.

scholarly journals The Relationship Between the Emission-Line Spectra and X-Ray/UV Continuum

1997 ◽  
Vol 159 ◽  
pp. 252-253
Author(s):  
Youjun Lu ◽  
Tinggui Wang
Keyword(s):  
Emission Line ◽  
Inverse Correlation ◽  
Baldwin Effect ◽  
Spectral Parameters ◽  
X Ray ◽  
Physical Conditions ◽  
Broad Emission ◽  
The Baldwin Effect ◽  
The Relationship ◽  
The Continuum

According to photoionization calculations, the broad emission-line (BEL) spectrum depends not only on the physical conditions of line-emitting gas, but also on the spectral shape of incident ionizing continuum, especially from the UV to X-ray. Analysis of emission-line spectra and their correlations with the continuum, therefore, provide a way of probing the anisotropy of ionizing continuum on the BLR scale, which is predicted by current models. Previous works have concentrated on explaining the Baldwin effect, an inverse correlation between equivalent width and continuum luminosity. In this contribution, we present the results of an analysis of 75 AGNs which have well-determined soft X-ray spectral parameters from ROSAT and UV line and continuum measurements.

scholarly journals The determination of the GX 339-4's mass based on its 2010 outburst

2010 ◽  
Vol 6 (S275) ◽  
pp. 327-328
Author(s):  
Tao Chen
Keyword(s):  
Black Hole ◽  
Timing Analysis ◽  
Periodic Oscillation ◽  
Spectral Parameters ◽  
Quasi Periodic Oscillation ◽  
Black Hole Candidate ◽  
Centroid Frequency ◽  
Timing Properties ◽  
The Relationship

AbstractIn this paper we investigate the quasi periodic oscillation (QPO) behavior of the black hole candidate GX 339-4 during its 2010 outburst using RXTE/PCA data. We perform spectral and timing analysis of the observations, where the QPOs are observed. We analyze the relationship between the centroid frequency of QPO and the spectral parameters. The correlation of spectral and timing properties can be used to estimate the mass of black hole with the scaling method. Using this method we estimate a mass of 7.5 ± 0.8 M⊙ of GX 339-4.

Mineralogy of the far-side lunar surface explored by Chang’E-4 with visible and near-infrared reflectance spectra

2021 ◽  
Author(s):  
Gen Ito ◽  
Jessica Flahaut ◽  
Jun Huang
Keyword(s):  
Near Infrared ◽  
Spectral Band ◽  
Reflectance Spectra ◽  
Composition Analysis ◽  
Near Infrared Reflectance ◽  
Spectral Parameters ◽  
Moon Mineralogy Mapper ◽  
Band Depth ◽  
The Relationship ◽  
Initial Classification

<p>The far side of the Moon, which has generally been less frequently targeted by robotic and human missions in the past, has become more available for compositional analyses with measurements made by the Chang’E-4 mission that landed in South Pole-Aitken Basin in 2019. The rover of the mission, Yutu-2, has traversed over 500 m now and acquired more than 100 measurements of visible and near-infrared (VNIR) reflectance spectra. In this study, we analyze the full set of VNIR reflectance spectra collected so far in order to better understand the geology of the Von Karman mare. We compute spectral parameters to quantize major features of spectra and infer mineralogy, e.g., pyroxene composition analysis using the relationship between spectral band depths at 1 µm and 2 µm. Many of Chang’E-4 spectra do not have a detectable spectral band at 2 µm in which case we use spectral parameters for the band at 1 µm to make classifications and infer the presence of other minerals. Pyroxene composition inferred from Chang’E-4 spectra are midway between orthopyroxene and clinopyroxene, showing noticeably unique grouping when compared with 1 µm and 2 µm band depth data available from past studies. For spectra without detectable band at 2 µm, initial classification efforts based solely on spectral parameters of the 1 µm band seem to indicate that at least two distinct groups exist. We are further investigating these preliminary findings, such as through comparisons to data from Moon Mineralogy Mapper, to better understand the mineralogy of the measured materials and the geology of the region explored by Yutu-2 rover. </p>

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