scholarly journals High dimensionality of the stability of a marine benthic ecosystem

2020 ◽  
Author(s):  
Nelson Valdivia ◽  
Moisés A. Aguilera ◽  
Bernardo R. Broitman
Keyword(s):  
Functional Responses ◽  
Four Dimensions ◽  
Environmental Regimes ◽  
Compositional Stability ◽  
Multiple Dimensions ◽  
Local Space ◽  
Southern Central ◽  
The Stability ◽  
Press Disturbance ◽  
Levels Of Functioning

AbstractStability is a central property of complex systems and encompasses multiple dimensions such as resistance, resilience, recovery, and invariability. How these dimensions correlate among them is focus of recent ecological research, but empirical evidence at regional scales, at which conservation decisions are usually made, remains absent. Using a field-based manipulative experiment conducted in two marine intertidal regions, we analyse the correlations among different aspects of stability in functioning (community cover) and composition of local communities facing a press disturbance. The experiment involved the removal of the local space-dominant species for 35 months in eight sites under different environmental regimes in northern- and southern-central Chile (ca. 30°S and 40°S, respectively). After the disturbance, the magnitude of the initial responses and the recovery patterns were similar among communities dominated by different species, but varied between the functional and compositional response variables, and among four dimensions of stability. The recovery trajectories in function and composition remained mostly uncorrelated across the system. Yet, larger initial functional responses were associated with faster recovery trajectories—high functional resilience, in turn, was associated with both, high and low variability in the pattern of recovery. Finally, the compositional stability dimensions were independent from each other. The results suggest that varying community compositions can perform similar levels of functioning, which might be the result of strong compensatory dynamics among species competing for space in these communities. Knowledge of several, and sometimes independent, aspects of stability is mandatory to fully describe the stability of complex ecological systems.

scholarly journals High Dimensionality of the Stability of a Marine Benthic Ecosystem

2021 ◽  
Vol 7 ◽  
Author(s):  
Nelson Valdivia ◽  
Moisés A. Aguilera ◽  
Bernardo R. Broitman
Keyword(s):  
Functional Responses ◽  
Four Dimensions ◽  
Environmental Regimes ◽  
Compositional Stability ◽  
Multiple Dimensions ◽  
Local Space ◽  
Southern Central ◽  
The Stability ◽  
Press Disturbance ◽  
Levels Of Functioning

Stability is a central property of complex systems and encompasses multiple dimensions such as resistance, resilience, recovery, and invariability. How these dimensions correlate among them is focus of recent ecological research, but empirical evidence at regional scales, at which conservation decisions are usually made, remains absent. Using a field-based manipulative experiment conducted in two marine intertidal regions, we analyze the correlations among different aspects of stability in functioning (community cover) and composition of local communities facing a press disturbance. The experiment involved the removal of the local space-dominant species for 35 months in eight sites under different environmental regimes in northern- and southern-central Chile (ca. 30 and 40°S, respectively). After the disturbance, the magnitude of the initial responses and the recovery patterns were similar among communities dominated by different species, but varied between the functional and compositional response variables, and among four dimensions of stability. The recovery trajectories in function and composition remained mostly uncorrelated across the system. Yet, larger initial functional responses were associated with faster recovery trajectories—high functional resilience, in turn, was associated with both, high and low variability in the pattern of recovery. Finally, the compositional stability dimensions were independent from each other. The results suggest that varying community compositions can perform similar levels of functioning, which might be the result of strong compensatory dynamics among species competing for space in these communities. Knowledge of several, and sometimes independent, aspects of stability is mandatory to fully describe the stability of complex ecological systems.

scholarly journals Hybrid Passivity Based and Fuzzy Type-2 Controller for Chaotic and Hyper-Chaotic Systems

2017 ◽  
Vol 11 (2) ◽  
pp. 96-103 ◽  
Author(s):  
Fernando Serrano ◽  
Josep M. Rossell
Keyword(s):  
Lyapunov Exponents ◽  
Chaotic System ◽  
Control Strategy ◽  
Chaotic Systems ◽  
Control Law ◽  
Four Dimensions ◽  
Design Requirements ◽  
The Stability ◽  
Theoretical Results

AbstractIn this paper a hybrid passivity based and fuzzy type-2 controller for chaotic and hyper-chaotic systems is presented. The proposed control strategy is an appropriate choice to be implemented for the stabilization of chaotic and hyper-chaotic systems due to the energy considerations of the passivity based controller and the flexibility and capability of the fuzzy type-2 controller to deal with uncertainties. As it is known, chaotic systems are those kinds of systems in which one of their Lyapunov exponents is real positive, and hyper-chaotic systems are those kinds of systems in which more than one Lyapunov exponents are real positive. In this article one chaotic Lorentz attractor and one four dimensions hyper-chaotic system are considered to be stabilized with the proposed control strategy. It is proved that both systems are stabilized by the passivity based and fuzzy type-2 controller, in which a control law is designed according to the energy considerations selecting an appropriate storage function to meet the passivity conditions. The fuzzy type-2 controller part is designed in order to behave as a state feedback controller, exploiting the flexibility and the capability to deal with uncertainties. This work begins with the stability analysis of the chaotic Lorentz attractor and a four dimensions hyper-chaotic system. The rest of the paper deals with the design of the proposed control strategy for both systems in order to design an appropriate controller that meets the design requirements. Finally, numerical simulations are done to corroborate the obtained theoretical results.

scholarly journals Distinct phosphorylation sites in a prototypical GPCR differently orchestrate β-arrestin interaction, trafficking, and signaling

2020 ◽  
Vol 6 (37) ◽  
pp. eabb8368 ◽  
Author(s):  
Hemlata Dwivedi-Agnihotri ◽  
Madhu Chaturvedi ◽  
Mithu Baidya ◽  
Tomasz Maciej Stepniewski ◽  
Shubhi Pandey ◽  
...  
Keyword(s):  
G Protein ◽  
Phosphorylation Site ◽  
Dynamics Simulation ◽  
Phosphorylation Sites ◽  
Functional Responses ◽  
Biased Signaling ◽  
The Stability ◽  
G Protein Coupled ◽  
Structural Aspects

Agonist-induced phosphorylation of G protein–coupled receptors (GPCRs) is a key determinant for their interaction with β-arrestins (βarrs) and subsequent functional responses. Therefore, it is important to decipher the contribution and interplay of different receptor phosphorylation sites in governing βarr interaction and functional outcomes. Here, we find that several phosphorylation sites in the human vasopressin receptor (V2R), positioned either individually or in clusters, differentially contribute to βarr recruitment, trafficking, and ERK1/2 activation. Even a single phosphorylation site in V2R, suitably positioned to cross-talk with a key residue in βarrs, has a decisive contribution in βarr recruitment, and its mutation results in strong G-protein bias. Molecular dynamics simulation provides mechanistic insights into the pivotal role of this key phosphorylation site in governing the stability of βarr interaction and regulating the interdomain rotation in βarrs. Our findings uncover important structural aspects to better understand the framework of GPCR-βarr interaction and biased signaling.

Immediacy as news experience: exploring its multiple dimensions in print and online contexts

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bahiyah Omar ◽  
Hosam Al-Samarraie ◽  
Bianca Wright
Keyword(s):  
Design Methodology ◽  
Design Experiment ◽  
Content Type ◽  
Four Dimensions ◽  
Print News ◽  
Multiple Dimensions ◽  
News Events

PurposeNews research scholars define immediacy as constant news updating, whereas scholars in other fields conceptualize it more broadly as meaning closeness. The present study explicates the concept of immediacy and proposes a multidimensional notion of news immediacy that reflects physical and psychological closeness to the news.Design/methodology/approachA scale for measuring multifaceted immediacy was developed and tested in a between-subjects design experiment. Four dimensions were extracted from the analysis: transportation, involvement, vividness and timeliness.FindingsThe results reveal greater immediacy in online than print news contexts. Involvement is key to the experience of immediacy in both contexts; yet the feeling of being transported to the places of the news events was stronger among online than print news users. The latter relied more on vividness of the news presentation to attain closeness to the news.Originality/valueImplications of the study were discussed.

scholarly journals Las cuatro dimensiones del fenómeno religioso: propuesta para un abordaje integral / The four dimensions of the religious phenomenon: proposal for an integral approach

Numen ◽  
2014 ◽  
Vol 17 (1) ◽  
Author(s):  
Catón Eduardo Carini
Keyword(s):  
Conceptual Framework ◽  
Human Life ◽  
Integral Approach ◽  
Scientific Theories ◽  
Ken Wilber ◽  
Research Traditions ◽  
Four Dimensions ◽  
The Third ◽  
Multiple Dimensions ◽  
The Way

RESUMEMEl artículo propone un modelo para pensar los fenómenos religiosos y las teorías científicas que sobre ellos se han construido. La primera parte expone dicho marco conceptual, basado en la obra de Ken Wilber, el cual diferencia entre cuatro dimensiones fundamentales de la vida humana. La segunda parte rastrea la forma en que estas dimensiones se revelan en la esfera religiosa y analiza cómo han dado origen a cuatro tradiciones de investigación en las ciencias de la religión. Finalmente, la tercera parte explora la forma de superar reduccionismos y propone una serie de ideas con respecto a los roles que juegan las representaciones sagradas en múltiples dimensiones de la vida.Palabras: clave: antropología- religión - teoría.ABSTRACTThe paper offers a model for thinking the religious phenomena and the scientific theories that have been built on them. The first part exposes such conceptual framework, based on the work of Ken Wilber, which differentiates four main dimensions of human life. The second, traces the way in which these dimensions are revealed in the religious sphere and analyzes how they have given birth to four research traditions in religion science. Finally, the third part explores how to overcome reductionism and suggests a series of ideas regarding the roles that sacred representations play in multiple dimensions of life.Keywords: anthropology – religion – theory.

scholarly journals Επιστημολογικές πεποιθήσεις: Διερεύνηση της δομής και της σχέσης τους με τη σχολική επίδοση σε μαθητές Λυκείου

2020 ◽  
Vol 16 (4) ◽  
pp. 321
Author(s):  
Φωτεινή Πολυχρόνη
Keyword(s):  
Academic Performance ◽  
Theoretical Model ◽  
Epistemological Beliefs ◽  
Theoretical Study ◽  
Self Regulation ◽  
Demographic Variables ◽  
Older Students ◽  
Four Dimensions ◽  
The Stability ◽  
Structure Of Knowledge

The term epistemological beliefs (EBs) refers to the nature of students’ beliefsof knowledge and learning, these are related to the learning process through their effect on academic performance, motivation and self-regulation. Schommer has argued that the concept is multidimensional and consists of four distinct dimensions, the structure of knowledge, the stability of knowledge, the ability of learning and the speed of learning. The aim of the present study is to explore the structure of epistemic beliefs in a Greek sample, according to the theoretical model of Schommer, and how these beliefs are related to academic performance and other demographic and non demographic variables. The sample was composed by 470 students attending the three gradesof upper high school. The students responded to the Epistemological Belief Questionnaire (Schommer, 2000). The results showed that the structure of the epistemological beliefs is in accordance to Schommer’s theoretical model as regards the four dimensions and that the dimension structure of knowledge was the strongest factor. Low reliability rates lead to doubts regarding Schommer’s conceptual model. Moreover, it was found that ability of learning and stability of knowledge significantly contribute to the prediction ofacademic performance and that higher grades are related to sophisticated EBs. It was also found that girlshave more sophisticated EBs than boys in the speed of learning, and that older students have more sophisticated EBs in the stability of knowledge. Similar findings were found for the students of the theoretical study direction in terms of the stability and the structure of knowledge.

scholarly journals Reliabitily study (test-retest) of the Scale for Conception of Disability (SCD)

Psico ◽  
2019 ◽  
Vol 50 (2) ◽  
pp. 29394
Author(s):  
Lucia Pereira Leite ◽  
Hugo Ferrari Cardoso
Keyword(s):  
Pearson Correlation ◽  
Social Groups ◽  
Temporal Stability ◽  
Total Sample ◽  
Public University ◽  
Sao Paulo ◽  
São Paulo ◽  
Four Dimensions ◽  
Study Test ◽  
The Stability

This article describes the reliability of the test-retest of the Scale for Conception of Disability (SCD), which comprehends four dimensions – biological, social, metaphysical and historical cultural – through the analysis of its temporal stability. In this study, a sample of 52 students from a public university of the State of São Paulo completed the same instrument with 30-day-interval between one another. For rating the stability, the Pearson correlation coefficient was used. In terms of total sample, the results of the SCD, as a whole, presented a correlation of strong magnitude (r=0,77) between test and retest. According to the results, the reliability of the scale was considered appropriate, recommending its use in studies that aim to find out how social groups conceive the disability, understanding that such conception guides the attitudes of society towards people in this condition. *** Estudo de confiabilidade (teste-reteste) da Escala Concepções de Deficiência (ECD) ***Este artigo traça uma síntese sobre concepções de deficiência circulantes nos discursos sociais e descreve a confiabilidade testereteste da Escala Concepções de Deficiência (EDC), que abrange quatro dimensões – biológica, social, metafísica e histórico cultural –, pela análise de sua estabilidade temporal. No estudo, uma amostra de 52 estudantes de uma universidade pública do Estado de São Paulo preencheu o mesmo instrumento, em duas oportunidades, com intervalo de trinta dias. Como medida de estabilidade, foi usado o teste de correlação de Pearson. Em termos da amostra total, os resultados da ECD, em sua totalidade, apresentaram correlação de magnitude forte (r=0,77) entre o teste e o reteste. De acordo com os resultados, a confiabilidade da escala foi considerada adequada, indicando sua utilização em estudos que procurem conhecer como grupos sociais concebem a deficiência, entendendo que tal concepção norteia as atitudes da sociedade diante das pessoas que se encontram nessa condição.Palavras-chave: confiabilidade; escala; concepção; pessoa com deficiência; teste-reteste.

scholarly journals Effects of Multiple Dimensions of Intangible Distance on Agro-food Exports: Evidence from China

2019 ◽  
Vol 11 (12) ◽  
pp. 75
Author(s):  
Xinran Liu
Keyword(s):  
Industrial Development ◽  
Eating Habits ◽  
Cultural Distance ◽  
Food Products ◽  
Distance Functions ◽  
Negative Effects ◽  
Four Dimensions ◽  
Multiple Dimensions ◽  
Trading Partners ◽  
The Individual

Intangible distance may play a role as both trade barriers and competitive advantages in cross-border trade. Moreover, for agro-food products, intangible distance reflects the discrepancy between eating habits of the importing and exporting countries, and thus affects agro-food trade also as “eating-habit distance”. This paper investigates the effects of four dimensions of intangible distance on China’s agro-food exports, namely, cultural distance, institutional distance, distance in education, and distance in industrial development. A panel data of 78 countries covering the period 2002-2016 is used, and an extended gravity model is employed. We control for the effects of quality or level of institution, education, and industrial development of China and its trading partners to distinguish the “quality effects” from “distance effects” and to test the robustness of the results. To explore the (possible) different effects of intangible distance on different categories of agro-food products, we consider not only the total agro-food exports, but also the individual samples of the four agro-food categories classified according to the Harmonized System codes. We find that all these dimensions of intangible distance influence China’s agro-food exports significantly, at least for certain categories of agro-food products. Distance in institution, education, and industrial development function as measures of trade costs, whereas cultural distance functions more like a reflection of competitive advantage. Furthermore, when the distance in institution, education or industrial development increases in favor of the importing countries, the negative effects of intangible distance are partly neutralized by the importers’ improved level of institution, education or industrialization.

Dynamics of a Discrete Prey–Predator Model with Mixed Functional Response

2019 ◽  
Vol 29 (14) ◽  
pp. 1950199
Author(s):  
Mohammed Fathy Elettreby ◽  
Aisha Khawagi ◽  
Tamer Nabil
Keyword(s):  
Type I ◽  
Time Behavior ◽  
Stable Fixed Point ◽  
Functional Responses ◽  
Predator Prey ◽  
Predator Prey Model ◽  
Dynamical Behaviors ◽  
Long Time ◽  
Predator Model ◽  
The Stability

In this paper, we propose a discrete Lotka–Volterra predator–prey model with Holling type-I and -II functional responses. We investigate the stability of the fixed points of this model. Also, we study the effects of changing each control parameter on the long-time behavior of the model. This model contains a lot of complex dynamical behaviors ranging from a stable fixed point to chaotic attractors. Finally, we illustrate the analytical results by some numerical simulations.

Outcome of Suicidal Ideation and Behavior in a Young, Help-Seeking Population over a 2-Year Period

Crisis ◽  
2007 ◽  
Vol 28 (1) ◽  
pp. 4-10 ◽  
Author(s):  
E.M. Cosgrave ◽  
J. Robinson ◽  
K.A. Godfrey ◽  
H.P. Yuen ◽  
E.J. Killackey ◽  
...  
Keyword(s):  
Suicidal Ideation ◽  
Suicidal Behavior ◽  
Help Seeking ◽  
Psychiatric Service ◽  
Completed Suicide ◽  
Axis I ◽  
The Stability ◽  
And Behavior ◽  
Levels Of Functioning

Abstract. Suicidal behavior is associated with negative outcomes, including completed suicide. This study examined the prevalence of suicidal behavior in a sample of referrals to a youth psychiatric service and investigated the stability of suicidality over 2 years. Of the 140 people (mean age 17.8) who were referred to a youth psychiatric service, 82 who were accepted for treatment (RA group) and 58 who were not accepted (RNA group) were assessed; 57% reported considering suicide and 39% reported attempting suicide in the 12 months prior to referral. Participants who reported suicidal ideation were significantly more likely than nonsuicidal participants to have multiple Axis I diagnoses and lower levels of functioning. At the 2-year follow-up there was a significant reduction in suicidality in the RA group, but not in the RNA group. In conclusion, suicidality is prevalent among young people referred to psychiatric services. Even brief contact with services results in a reduction in suicidality over 2 years.

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