scholarly journals Stability of typologies produced on the basis of repeated measurement with the role relationship and the name generator approach

2009 ◽  
Vol 6 (2) ◽  
Author(s):  
Tina Kogovšek ◽  
Valentina Hlebec
Keyword(s):  
Sampling Procedure ◽  
Second Step ◽  
Considerable Effort ◽  
Survey Question ◽  
Role Relationship ◽  
Overall Stability ◽  
Network Composition ◽  
The Stability ◽  
Complex Coordination ◽  
Experimental Group

In measuring ego-centered social networks, two general approaches can be distinguished. A very simple way to evaluate membership in a social network is to ask an ordinary survey question where response categories are types of relationships (e.g., partner, parents, children, friends, etc.). This approach (usually called the role relation(ship) approach) is very appealing as it saves time and money. However, information obtained by this approach is very limited. Most often, when evaluating ego-centered networks, the name generator approach is used. The list of egos (respondents) is obtained in the first step. In the second step, existing ties are identified - all alters with whom the focal ego has some sort of relationship. When all ties have been identified, the contents and the characteristics of ties are assessed. In most cases the characteristics of the alters are also measured. The name generator approach yields more data and is also of higher quality. However, it is time and money consuming, and it requires either considerable effort from respondents, when it is applied in self-administered mode, or complex coordination between interviewer and respondent, when it is applied in personal interviews (e.g., Kogovšek et al., 2002). In a series of studies (e.g., Hlebec and Kogovšek, 2005; Kogovšek and Hlebec, 2005; Kogovšek and Hlebec, 2008), network composition was estimated using both approaches. Test-retest and split-ballot experiments on convenience samples of respondents were used to assess the stability of network composition. Findings show that, with some caution, the two approaches are comparable. In the present paper this line of research is taken a step further. Typologies of social support networks are produced by hierarchical clustering on the basis of network composition, estimated by both approaches. Overall stability of typologies as well as stability of clustering of individual respondents is studied by means of simple descriptive analyses and by discriminant analysis. The results show that the overall stability of typologies is relatively high – two to three cluster groups are obtained in each analysis. However, the typologies seem to be more stable in one experimental group. Also the stability of clustering for individual respondents seems quite high as 73% to 85% of respondents were correctly classified. Incorrectly classified respondents were also studied, but their characteristics may well reflect the specific characteristics of the sampling procedure rather than some other systematic factor.

scholarly journals Measuring ego-centered social networks

2008 ◽  
Vol 5 (2) ◽  
Author(s):  
Tina Kogovšek ◽  
Valentina Hlebec
Keyword(s):  
Social Networks ◽  
Social Network ◽  
Second Step ◽  
Considerable Effort ◽  
Survey Question ◽  
Respondent Burden ◽  
Network Composition ◽  
The Stability ◽  
Complex Coordination

In measuring ego-centered social networks, two general approaches can be distinguished. A very simple way to evaluate membership in a social network is to ask an ordinary survey question where response categories are types of relationships (e.g., partner, parents, children, friends, etc.). This approach is very appealing as it saves time and money. However, information obtained by this approach is very limited. Most often, when evaluating ego-centered networks, the name generator approach is used. The list of egos (respondents) is obtained in the first step. In the second step, existing ties are identified - all alters with whom the focal ego has some sort of relationship. When all ties have been identified, the contents and the characteristics of ties are assessed. In most cases the characteristics of the alters are also measured. The name generator approach yields more data and is also of higher quality. However, it is very time and money consuming, and it requires either considerable effort from respondents, when it is applied in self-administered mode, or complex coordination between interviewer and respondent, when it is applied in personal interviews (e.g., Kogovšek et al., 2002). In a series of studies, network composition was estimated using both approaches. Test-retest and split-ballot experiments on convenience samples of respondents were used to assess the stability of network composition. Findings are discussed with regard to survey complexity, respondent burden, costs and quality of network composition estimates.

scholarly journals Stability charts based on the finite element method for underground cavities in soft carbonate rocks: validation through case-study applications

2019 ◽  
Vol 19 (10) ◽  
pp. 2079-2095 ◽  
Author(s):  
Michele Perrotti ◽  
Piernicola Lollino ◽  
Nunzio Luciano Fazio ◽  
Mario Parise
Keyword(s):  
Finite Element ◽  
Safety Margin ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Geometrical Features ◽  
Overall Stability ◽  
Underground Cavities ◽  
The Stability ◽  
Rock Mechanical Properties

Abstract. The stability of man-made underground cavities in soft rocks interacting with overlying structures and infrastructures represents a challenging problem to be faced. Based upon the results of a large number of parametric two-dimensional (2-D) finite-element analyses of ideal cases of underground cavities, accounting for the variability both cave geometrical features and rock mechanical properties, specific charts have been recently proposed in the literature to assess at a preliminary stage the stability of the cavities. The purpose of the present paper is to validate the efficacy of the stability charts through the application to several case studies of underground cavities, considering both quarries collapsed in the past and quarries still stable. The stability graphs proposed by Perrotti et al. (2018) can be useful to evaluate, in a preliminary way, a safety margin for cavities that have not reached failure and to detect indications of predisposition to local or general instability phenomena. Alternatively, for sinkholes that already occurred, the graphs may be useful in identifying the conditions that led to the collapse, highlighting the importance of some structural elements (as pillars and internal walls) on the overall stability of the quarry system.

scholarly journals SEA-BED CONFIGURATION IN RELATION TO BREAKWATER STABILITY

1972 ◽  
Vol 1 (13) ◽  
pp. 81 ◽  
Author(s):  
J.H. Van Oarschat ◽  
A. Wevers
Keyword(s):  
The Netherlands ◽  
Present Article ◽  
Water Depth ◽  
Systematic Study ◽  
Public Works ◽  
Irregular Waves ◽  
Sea Bed ◽  
Hydraulic Conditions ◽  
Overall Stability ◽  
The Stability

Stability tests on the Europoort breakwaters, situated on a shallow foreshore, clearly demonstrated the effect of the foreshore configuration on the overall stability. The present article gives a descriptionof the stability experiments and the interpretation leading to general conclusions regarding foreshore effects in combination with hydraulic conditions such as wave period, water depth and wave height. Both regular and irregular waves have been used. The experiments, carried out in commission of the Netherlands Government Department of Public Works (Rijkswaterstaat) were of an applied nature and were not directed primarily to the systematic study of foreshore effects.

scholarly journals The stability of major and trace element concentrations from musts to Champagne during the production process

OENO One ◽  
2022 ◽  
Vol 56 (1) ◽  
pp. 29-40
Author(s):  
Robin Cellier ◽  
Sylvain Berail ◽  
Ekaterina Epova ◽  
Julien Barre ◽  
Fanny Claverie ◽  
...  
Keyword(s):  
Trace Elements ◽  
Production Process ◽  
Trace Element ◽  
Narrow Range ◽  
Grape Juice ◽  
Elemental Concentrations ◽  
Element Concentrations ◽  
Production Processes ◽  
Overall Stability ◽  
The Stability

Thirty-nine Champagnes from six different brands originating from the AOC Champagne area were analyzed for major and trace element concentrations in the context of their production processes and in relation to their geographical origins. Inorganic analyses were performed on the must (i.e., grape juice) originating from different AOC areas and the final Champagne. The observed elemental concentrations displayed a very narrow range of variability. Typical concentrations observed in Champagne are expressed in mg/L for elements such as K, Ca, Mg, Na, B, Fe, A, and Mn. They are expressed in µg/L for trace elements such as Sr, Rb, Ba, Cu, Ni, Pb Cr and Li in decreasing order of concentrations. This overall homogeneity was observed for Sr and Rb in particular, which showed a very narrow range of concentrations (150 < Rb < 300 µg/L and 150 < Sr < 350 µg/L) in Champagne. The musts contained similar levels of concentration but showed slightly higher variability since they are directly influenced by the bedrock, which is quite homogenous in the AOC area being studied. Besides the homogeneity of the bedrock, the overall stability of the concentrations recorded in the samples can also be directly linked to the successive blending steps, both at the must level and prior to the final bottling. A detailed analysis of the main additives, sugar, yeast and bentonite, during the Champagne production process, did not show a major impact on the elemental signature of Champagne.

scholarly journals Evolution and stability of chromosomal DNA coamplified with the CAD gene.

1989 ◽  
Vol 9 (6) ◽  
pp. 2445-2452 ◽  
Author(s):  
I Saito ◽  
R Groves ◽  
E Giulotto ◽  
M Rolfe ◽  
G R Stark
Keyword(s):  
Syrian Hamster ◽  
Copy Number ◽  
High Copy Number ◽  
Second Step ◽  
Chromosomal Dna ◽  
Average Amount ◽  
Large Domain ◽  
Cad Gene ◽  
The Stability ◽  
Striking Contrast

We have compared clones of Syrian hamster cells selected for the first amplification of the CAD gene with clones selected for further amplification. The large domain amplified initially was not reamplified as an intact unit. Instead, subregions were reamplified preferentially, and parts of the initial array were often lost. These events reduced the average amount of coamplified DNA accompanying each copy of the selected gene. The degree of amplification was small in the first step (about three extra copies of CAD per cell), but second-step amplifications to a high copy number (up to 60 extra copies per cell) occurred frequently. After several separate steps of amplification, highly condensed arrays that brought many CAD genes close together were formed. In striking contrast to the stability of these highly amplified arrays, the low-copy chromosomal arrays formed early were quite unstable and were often lost completely within 1 or 2 months of growth without selection. The results suggest that different mechanisms may be involved in the first step of amplification and in the later evolution of an already amplified array.

scholarly journals Evaluation of the effect of force direction on stationary anchorage success of mini-implant with a lever-arm–shaped upper structure

2011 ◽  
Vol 81 (5) ◽  
pp. 776-782 ◽  
Author(s):  
Ki-Ho Park ◽  
Eun-Man Lee ◽  
Seung-il Shin ◽  
Seong-Hun Kim ◽  
Young-Guk Park ◽  
...  
Keyword(s):  
Primary Stability ◽  
The Other ◽  
Control Group ◽  
Removal Torque ◽  
Lever Arm ◽  
Mini Implants ◽  
Force Direction ◽  
The Mean ◽  
The Stability ◽  
Experimental Group

Abstract Objective: To compare the effect of clockwise and counterclockwise torque on the primary stability of a mini-implant with a lever-arm–shaped upper structure. Materials and Methods: Twenty-four white rabbits were used for this study. Two screw-type mini-implants were placed in each tibia. In all, 96 screws were inserted. Two weeks later, a 2-N force was applied to the mini-implants without an upper structure in eight rabbits (control group). The mini-implants of the other 16 rabbits were loaded with an upper structure (experimental group). In the experimental group, the two left mini-implants were loaded in a clockwise direction (CW group) and the two right implants were loaded in a counterclockwise direction (CCW group). The rabbits were sacrificed at 1 week or 8 weeks after loading in both control and experimental groups. The removal torque value (RTV) was measured in 15 of 16 mini-implants in each group and the remaining implant was processed for histologic examination. Results: At 1 week there were no significant differences in the mean RTV between the control, CW, and CCW groups. At 8 weeks, the RTV was higher in the control and experimental groups than in the respective 1-week groups. At 8 weeks, there were no significant differences in the RTV between the control and CW groups, but the CCW group showed a lower RTV. Conclusions: CCW torque can decrease the stability of a mini-implant, whereas a CW torque has no effect.

Conceptual Flutter Analysis of Stepped Labyrinth Seals

2019 ◽  
Author(s):  
Roque Corral ◽  
Almudena Vega ◽  
Michele Greco
Keyword(s):  
Natural Frequency ◽  
Fundamental Mode ◽  
Second Step ◽  
Pressure Side ◽  
Dimensional Model ◽  
Labyrinth Seals ◽  
Acoustic Frequency ◽  
Flutter Analysis ◽  
Dimensional Parameters ◽  
The Stability

Abstract A simple non-dimensional model to describe the flutter onset of two-fin straight labyrinth seals [1] is extended to stepped seals. The effect of the axial displacement of the seal is analyzed first in isolation. It is shown that this fundamental mode is always stable. In a second step, the combination of axial and torsion displacements is used to determine the damping of modes with arbitrary torsion centers. It is concluded that the classical Abbot’s criterion stating that seals supported in the low-pressure side of the seal are stable provided that natural frequency of the mode is greater than the acoustic frequency breaks down under certain conditions. An analytical expression for the non-dimensional work-per-cycle is derived and new non-dimensional parameters controlling the seal stability identified. It is finally concluded the stability of stepped seals can be assimilated to that of a straight through seal if the appropriate distance of the torsion center to the seal is chosen.

scholarly journals Thermodynamic and Spectroscopic Studies of the Complexes Formed in Tartaric Acid and Lanthanide(III) Ions Binary Systems

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1121 ◽  
Author(s):  
Michal Zabiszak ◽  
Martyna Nowak ◽  
Zbigniew Hnatejko ◽  
Jakub Grajewski ◽  
Kazuma Ogawa ◽  
...  
Keyword(s):  
Tartaric Acid ◽  
Stability Constants ◽  
Binary Systems ◽  
Equilibrium Constants ◽  
Spectroscopic Studies ◽  
Luminescence Spectroscopy ◽  
Binary Complexes ◽  
Overall Stability ◽  
The Stability

Binary complexes of tartaric acid with lanthanide(III) ions were investigated. The studies have been performed in aqueous solution using the potentiometric method with computer analysis of the data for detection of the complexes set, determination of the stability constants of these compounds. The mode of the coordination of complexes found was determined using spectroscopy, which shows: Infrared, circular dichroism, ultraviolet, visible as well as luminescence spectroscopy. The overall stability constants of the complexes as well as the equilibrium constants of the reaction were determined. Analysis of the equilibrium constants of the reactions and spectroscopic data allowed the effectiveness of the carboxyl groups in the process of complex formation.

scholarly journals Study on the Stability of the Geogrids-Reinforced Earth Slope under the Coupling Effect of Rainfall and Earthquake

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Xijun Zhang ◽  
Liang Huang ◽  
Yujie Hou ◽  
Bo Wang ◽  
Binghan Xue ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Coupling Effect ◽  
Calculation Model ◽  
Influential Factor ◽  
Construction Design ◽  
Reinforced Earth ◽  
Overall Stability ◽  
Earth Slope ◽  
Earth Slopes ◽  
The Stability

This paper focuses on understanding the dynamic response problem of flexible wrapped reinforced Earth slope under the coupling effect of earthquake and rainfall; a numerical calculation model of reinforced Earth slope considering the coupling effect of earthquake and rainfall was established. The dynamic response, pore pressure, and tensile stress distribution of the reinforcement under the rainfall before earthquake, the rainfall after the earthquake, and earthquake-rainfall are studied. The results show that the coupling effect of earthquake and rainfall is an influential factor in the dynamic analysis of reinforced Earth slopes, the analysis of which should be paid attention to and researched in the future. The combination of geogrid and soil effectively improves the deformation of the slope and the overall stability, reduces the secondary disaster of the slope, and provides a reference for the seismic construction design of the reinforced Earth slope.

Research on Overall Stability of Concrete-Filled Steel Tubular Bowstring Arch Bridge

2011 ◽  
Vol 243-249 ◽  
pp. 1988-1994 ◽  
Author(s):  
Zi Lin Li ◽  
Pei Yuan Zhou
Keyword(s):  
Finite Element ◽  
Steel Tube ◽  
Construction Process ◽  
Ansys Software ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Overall Stability ◽  
The Stability ◽  
Tied Arch Bridge ◽  
Element Theory

Based on the finite element theory, the computational model, one through concrete filled steel tube tied-arch bridge was established under the considerations of both geometrical non-linearity and material non-linearity. And using the ANSYS software to study the bridge's arch rib construction process and the overall stability after the complete construction, the results show that the full-bridge’s stability coefficient are larger than other concrete-filled steel tube arch bridge; the in-plane stiffness is larger than the out-plane stiffness, and the influence of material non-linearity on the stability is notable. The results provide a good reference for the similar bridge's design and construction.

Sign in / Sign up

Export Citation Format

Share Document