Inclusion of Side Signals on GNSS Water Vapor Tomography with a New Height Factor Model

2020 ◽  
pp. 76-88
Author(s):  
Wenyuan Zhang ◽  
Nan Ding ◽  
Shubi Zhang
Keyword(s):  
Water Vapor ◽  
Factor Model ◽  
Height Factor

scholarly journals A Tropospheric Tomography Method with a Novel Height Factor Model Including Two Parts: Isotropic and Anisotropic Height Factors

2020 ◽  
Vol 12 (11) ◽  
pp. 1848 ◽  
Author(s):  
Wenyuan Zhang ◽  
Shubi Zhang ◽  
Nan Ding ◽  
Qingzhi Zhao
Keyword(s):  
Water Vapor ◽  
Factor Model ◽  
Traditional Approach ◽  
Satellite System ◽  
Spatiotemporal Variability ◽  
Radiosonde Data ◽  
Key Factor ◽  
Improved Model ◽  
Global Navigation Satellite ◽  
Height Factor

Global Navigation Satellite System (GNSS) tomography has developed into an efficient tool for sensing the high spatiotemporal variability of atmospheric water vapor. The integration of GNSS top signals and side rays for tropospheric tomography systems using a novel height factor model (HFM) is proposed and discussed in this paper. Within the HFM, the sectional slant wet delay (SWD) of inside signals (the part of the side signal inside the tomography area), which is considered a key factor for modeling side rays, is separated into isotropic and anisotropic components. Correspondingly, two height factors are defined to calculate the isotropic and anisotropic part of tropospheric delays in the HFM. In addition, the dynamic tomography top boundary is first analyzed and determined based on 30-year radiosonde data to reasonably divide signals into top and side rays. Four special experimental schemes based on different tomography regions of Hong Kong are performed to assess the proposed HFM method, the results of which show increases of 33.42% in the mean utilization of rays, as well as decreases of 0.46 g/m3 in the average root mean square error (RMSE), compared to the traditional approach, revealing the improvement of tomography solutions when the side signals are included in the modeling. Furthermore, compared with the existing correction model for modeling side rays, the water vapor profiles retrieved from the proposed improved model are closer to the radiosonde data, which highlights the advantages of the proposed HFM for optimizing the GNSS tomography model.

New Design for a Differentially Pumped Hydration Chamber for a Siemens IA

1971 ◽  
Vol 29 ◽  
pp. 44-45
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscopy ◽  
Water Vapor ◽  
Electron Diffraction ◽  
Water Vapor Pressure ◽  
Biological Materials ◽  
Thin Membrane ◽  
Reliable System ◽  
System A ◽  
Water Films ◽  
Aperture Opening

Electron microscopy and diffraction of biological materials in the hydrated state requires the construction of a chamber in which the water vapor pressure can be maintained at saturation for a given specimen temperature, while minimally affecting the normal vacuum of the remainder of the microscope column. Initial studies with chambers closed by thin membrane windows showed that at the film thicknesses required for electron diffraction at 100 KV the window failure rate was too high to give a reliable system. A single stage, differentially pumped specimen hydration chamber was constructed, consisting of two apertures (70-100μ), which eliminated the necessity of thin membrane windows. This system was used to obtain electron diffraction and electron microscopy of water droplets and thin water films. However, a period of dehydration occurred during initial pumping of the microscope column. Although rehydration occurred within five minutes, biological materials were irreversibly damaged. Another limitation of this system was that the specimen grid was clamped between the apertures, thus limiting the yield of view to the aperture opening.

Hydration Chamber for Jeolco 200 Kv Microscope

1970 ◽  
Vol 28 ◽  
pp. 542-543
Author(s):  
V. R. Matricardi ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscope ◽  
Water Vapor ◽  
Vapor Pressure ◽  
Pressure Gradient ◽  
Room Temperature ◽  
List Type ◽  
Type Number ◽  
Equilibrium Vapor Pressure

In order to observe room temperature hydrated specimens in an electron microscope, the following conditions should be satisfied: The specimen should be surrounded by water vapor as close as possible to the equilibrium vapor pressure corresponding to the temperature of the specimen.The specimen grid should be inserted, focused and photo graphed in the shortest possible time in order to minimize dehydration.The full area of the specimen grid should be visible in order to minimize the number of changes of specimen required.There should be no pressure gradient across the grid so that specimens can be straddled across holes.Leakage of water vapor to the column should be minimized.

Warm and freeze-fracture of cotton seed radicles

1987 ◽  
Vol 45 ◽  
pp. 984-985
Author(s):  
E. L. Vigil ◽  
E. F. Erbe
Keyword(s):  
Thin Film ◽  
Water Vapor ◽  
Fracture Surface ◽  
Membrane Structure ◽  
Room Temperature ◽  
Freeze Fracture ◽  
Longitudinal Axis ◽  
Fracture Plane ◽  
Cotton Seeds ◽  
Condensed Water

In cotton seeds the radicle has 12% moisture content which makes it possible to prepare freeze-fracture replicas without fixation or cryoprotection. For this study we have examined replicas of unfixed radicle tissue fractured at room temperature to obtain data on organelle and membrane structure.Excised radicles from seeds of cotton (Gossyplum hirsutum L. M-8) were fractured at room temperature along the longitudinal axis. The fracture was initiated by spliting the basal end of the excised radicle with a razor. This procedure produced a fracture through the tissue along an unknown fracture plane. The warm fractured radicle halves were placed on a thin film of 100% glycerol on a flat brass cap with fracture surface up. The cap was rapidly plunged into liquid nitrogen and transferred to a freeze- etch unit. The sample was etched for 3 min at -95°C to remove any condensed water vapor and then cooled to -150°C for platinum/carbon evaporation.

Psychometrical Properties of a French Version of the General Self-Efficacy Short Scale (ASKU)

2020 ◽  
Vol 79 (1) ◽  
pp. 15-25
Author(s):  
Jean Philippe Décieux ◽  
Philipp Emanuel Sischka ◽  
Anette Schumacher ◽  
Helmut Willems
Keyword(s):  
Self Efficacy ◽  
Factor Model ◽  
German Version ◽  
French Version ◽  
Context Variable ◽  
Confirmatory Factor ◽  
French Speaking ◽  
German Speaking ◽  
Valid Instrument ◽  
General Self Efficacy

Abstract. General self-efficacy is a central personality trait often evaluated in surveys as context variable. It can be interpreted as a personal coping resource reflecting individual belief in one’s overall competence to perform across a variety of situations. The German-language Allgemeine-Selbstwirksamkeit-Kurzskala (ASKU) is a reliable and valid instrument to assess this disposition in the German-speaking countries based on a three-item equation. This study develops a French version of the ASKU and tests this French version for measurement invariance compared to the original ASKU. A reliable and valid French instrument would make it easy to collect data in the French-speaking countries and allow comparisons between the French and German results. Data were collected on a sample of 1,716 adolescents. Confirmatory factor analysis resulted in a good fit for a single-factor model of the data (in total, French, and German version). Additionally, construct validity was assessed by elucidating intercorrelations between the ASKU and different factors that should theoretically be related to ASKU. Furthermore, we confirmed configural and metric as well as scalar invariance between the different language versions, meaning that all forms of statistical comparison between the developed French version and the original German version are allowed.

Exploring the Multidimensional Facets of Authoritarianism: Authoritarian Aggression and Social Dominance Orientation

2008 ◽  
Vol 67 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Stefano Passini
Keyword(s):  
Social Dominance ◽  
Factor Model ◽  
Three Dimensional ◽  
Social Dominance Orientation ◽  
Model Fit ◽  
Regression Analyses ◽  
One Dimensional ◽  
Confirmatory Factor ◽  
The One ◽  
Better Than

The relation between authoritarianism and social dominance orientation was analyzed, with authoritarianism measured using a three-dimensional scale. The implicit multidimensional structure (authoritarian submission, conventionalism, authoritarian aggression) of Altemeyer’s (1981, 1988) conceptualization of authoritarianism is inconsistent with its one-dimensional methodological operationalization. The dimensionality of authoritarianism was investigated using confirmatory factor analysis in a sample of 713 university students. As hypothesized, the three-factor model fit the data significantly better than the one-factor model. Regression analyses revealed that only authoritarian aggression was related to social dominance orientation. That is, only intolerance of deviance was related to high social dominance, whereas submissiveness was not.

A Psychometric Study of the Quality Perception Questionnaire

2012 ◽  
Vol 71 (2) ◽  
pp. 101-106 ◽  
Author(s):  
Raffaele Cioffi† ◽  
Anna Coluccia ◽  
Fabio Ferretti ◽  
Francesca Lorini ◽  
Aristide Saggino ◽  
...  
Keyword(s):  
Structural Equation ◽  
Factor Model ◽  
Equation Modeling ◽  
Fit Indices ◽  
Quality Perception ◽  
Italian Survey ◽  
Confirmatory Factor ◽  
Instrument Measuring ◽  
Hospital Structures

The present paper reexamines the psychometric properties of the Quality Perception Questionnaire (QPQ), an Italian survey instrument measuring patients’ perceptions of the quality of a recent hospital admission experience, in a sample of 4400 patients (Mage = 56.42 years; SD = 19.71 years, 48.8% females). The 14-item survey measures four factors: satisfaction with medical doctors, nursing staff, auxiliary staff, and hospital structures. First, we tested two models using a confirmatory factor analysis (structural equation modeling): a four orthogonal factor and a four oblique factor model. The SEM fit indices and the χ² difference suggested the acceptance of the second model. We then did a simulation using a bootstrap with 1000 replications. Results confirmed the four oblique factor solution. Third, we tested whether there were significant differences with respect to age or sex. The multivariate general linear model showed no significant differences in the factors with respect to sex or age.

Question Wording Effects in the Assessment of Global Self-Esteem

2000 ◽  
Vol 16 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Martin Dunbar ◽  
Graeme Ford ◽  
Kate Hunt ◽  
Geoff Der
Keyword(s):  
Reading Ability ◽  
Factor Model ◽  
Self Esteem ◽  
Reading Scores ◽  
Poor Reading ◽  
Method Effect ◽  
Two Samples ◽  
Positive Item ◽  
Method Effects ◽  
Best Fit

Summary: Marsh (1996) produced evidence that method effects associated with negatively worded items might be responsible for the results of earlier factor analytic studies that reported finding positive and negative self-esteem factors in the Rosenberg Global self-esteem scale ( Rosenberg, 1965 ). He analyzed data collected from children using a 7-item self-esteem measure. This report details attempts to replicate Marsh 's analysis in data collected from two samples of adults who completed the full 10-item Global Self-Esteem (GSE) scale. The results reported here are similar to those given by Marsh in so much as a correlated uniquenesses model produced a superior fit to the data than the simple one factor model (without correlated uniquenesses) or the often reported two factor (positive and negative self-esteem) model. However, whilst Marsh reported that the best fit was produced by allowing negative item uniquenesses to correlate with each other, the model that produced the best fit to these data was one that contained correlated positive item uniquenesses. Supporting his claim that differential responding to negative and positive self-esteem items reflects a method effect associated with reading ability, Marsh also showed that factors associated with negative and positive items were most distinct among children who had poor reading scores. We report a similar effect among a sample of older adults where the correlation between these factors was compared across two groups who were selected according to their scores on a test of verbal reasoning.

Social Desirability in Personality Inventories

2014 ◽  
Vol 35 (3) ◽  
pp. 144-157 ◽  
Author(s):  
Martin Bäckström ◽  
Fredrik Björklund
Keyword(s):  
Social Desirability ◽  
Big Five ◽  
Work Performance ◽  
Factor Model ◽  
Five Factor Model ◽  
Peer Ratings ◽  
Personality Inventories ◽  
Model Study ◽  
The Difference ◽  
New Variables

The difference between evaluatively loaded and evaluatively neutralized five-factor inventory items was used to create new variables, one for each factor in the five-factor model. Study 1 showed that these variables can be represented in terms of a general evaluative factor which is related to social desirability measures and indicated that the factor may equally well be represented as separate from the Big Five as superordinate to them. Study 2 revealed an evaluative factor in self-ratings and peer ratings of the Big Five, but the evaluative factor in self-reports did not correlate with such a factor in ratings by peers. In Study 3 the evaluative factor contributed above the Big Five in predicting work performance, indicating a substance component. The results are discussed in relation to measurement issues and self-serving biases.

Validation of the Short Dark Triad in a German Sample

2020 ◽  
pp. 1-12
Author(s):  
Caroline Wehner ◽  
Ulrike Maaß ◽  
Marius Leckelt ◽  
Mitja D. Back ◽  
Matthias Ziegler
Keyword(s):  
Sensation Seeking ◽  
Factor Model ◽  
Structural Models ◽  
Self Esteem ◽  
Dark Triad ◽  
Fit Indices ◽  
Nomological Network ◽  
Competitive Test ◽  
Three Factor ◽  
Behavioral Criteria

Abstract. The structure, correlates, and assessment of the Dark Triad are widely discussed in several fields of psychology. Based on the German version of the Short Dark Triad (SDT), we add to this by (a) providing a competitive test of existing structural models, (b) testing the nomological network, and (c) proposing an ultrashort 9-item version of the SDT (uSDT). A sample of N = 969 participants provided data on the SDT and a range of further measures. Our competitive test of five structural models revealed that fit indices and nomological network assumptions were best met in a three-factor model, with separate factors for psychopathy, Machiavellianism, and narcissism. The results provided an extensive overview of the raw, unique, and shared associations of Dark Triad dimensions with narcissism facets, sadism, impulsivity, self-esteem, sensation seeking, the Big Five, maladaptive personality traits, sociosexual orientation, and behavioral criteria. Finally, the uSDT exhibited satisfactory psychometric properties. The highest overlap in expected relations between SDT and uSDT, and convergent and discriminant measures was also found for the three-factor model. Our study underlines the utility of a three-factor model of the Dark Triad, extends findings on its nomological network, and provides an ultrashort instrument.

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