1,285 research outputs found
Boundary object or bridging concept? A citation network analysis of resilience.
ArticleMany recent studies observe the increasing importance, influence, and analysis of resilience as a concept to understand the capacity of a system or individual to respond to change. The term has achieved prominence in diverse scientific fields, as well as public discourse and policy arenas. As a result, resilience has been referred to as a boundary object or a bridging concept that is able to facilitate communication and understanding across disciplines, coordinate groups of actors or stakeholders, and build consensus around particular policy issues. We present a network analysis of bibliometric data to understand the extent to which resilience can be considered as a boundary object or a bridging concept in terms of its links across disciplines and scientific fields. We analyzed 994 papers and 35,952 citations between them to reveal the connectedness and links between and within fields. We analyzed the network according to different fields, modules, and sub-fields, showing a highly clustered citation network. Analyzing betweenness allowed us to identify how particular papers bridge across fields and how different fields are linked. With the exception of a few specific papers, most papers cite exclusively within their own field. We conclude that resilience is to an extent a boundary object because there are shared understandings across diverse disciplines and fields. However, it is more limited as a bridging concept because the citations across fields are concentrated among particular disciplines and papers, so the distinct fields do not widely or routinely refer to each other. There are some signs of resilience being used as an interdisciplinary concept to bridge scientific fields, particularly in social-ecological systems, which may itself constitute an emerging sub-field.Center for Behavior, Institutions and the Environment at Arizona State UniversityNSFESR
Estudo comparativo de dois métodos de arraste principal do desbaste de Pinus taeda L.
Desempenho e custos na operação de arraste principal de dois tratores agrícolas com implementos diferentes foram submetidos a uma análise crítica, em uma plantação de Pinus taeda, com nove anos de idade e desbastada de forma sistemática e seletiva. A pesquisa foi instalada na Fazenda Monte Alegre, município de Telêmaco Borba, PR. Foram testados tratores do tipo MF 265 e os seguintes implementos de arraste: a) barra com fendas para engatar correntes, de segurar feixes de fustes, e b) pinça hidráulica traseira e lâmina hidráulica na frente. Sob as mesmas condições de distância e volume arrastado, os rendimentos foram similares, porém apresentaram grandes diferenças, quando baseados em volumes médios da carga. O trator com barra e correntes apresentou um volume médio de 0,8 m3 por ciclo e, numa distância média de 200 m, um rendimento de 6,85 m3/h, a um custo de Cr 82,10/m3. Sob as condições testadas, convém utilizar o trator com barra quando houver disponibilidade de mão-de-obra, pois arrasta maior volume de madeira por unidade de tempo a um custo mais baixo e com um grau de mecanização menor, portanto menos susceptível a falhas mecânicas. A exigência de maior tempo de oficina, com consertos e manutenção, em função da necessidade do equipamento, reduz a produção média anual em 35%, aproximadamente, no caso do trator com pinça. Detectaram-se, em ambos os métodos, grandes possibilidades de racionalização e, por conseguinte, de redução dos custos de arraste entre 24 e 27%
Anomalous Breaking of Anisotropic Scaling Symmetry in the Quantum Lifshitz Model
In this note we investigate the anomalous breaking of anisotropic scaling
symmetry in a non-relativistic field theory with dynamical exponent z=2. On
general grounds, one can show that there exist two possible "central charges"
which characterize the breaking of scale invariance. Using heat kernel methods,
we compute these two central charges in the quantum Lifshitz model, a free
field theory which is second order in time and fourth order in spatial
derivatives. We find that one of the two central charges vanishes.
Interestingly, this is also true for strongly coupled non-relativistic field
theories with a geometric dual described by a metric and a massive vector
field.Comment: 26 pages; major revision (results were unaffected), published versio
Propriedades físicas e químicas e rendimentos da destilação seca da madeira de Grevillea robusta.
bitstream/CNPF-2009-09/15736/1/circ-tec40.pd
Irrigation experiments in the lab: trust, environmental variability, and collective action
Research on collective action and common-pool resources is extensive. However, little work has concentrated on the effect of variability in resource availability and collective action, especially in the context of asymmetric access to resources. Earlier works have demonstrated that environmental variability often leads to a reduction of collective action in the governance of shared resources. Here we assess how environmental variability may impact collective action. We performed a behavioral experiment involving an irrigation dilemma. In this dilemma participants invested first into a public fund that generated water resources for the group, which were subsequently appropriated by one participant at a time from head end to tail end. The amount of resource generated for the given investment level was determined by a payoff table and a stochastic event representing environmental variability, i.e., rainfall. Results show that that (1) upstream users’ behavior is by far the most important variable in determining the outcome of collective action; (2) environmental variability (i.e. risk level in investing in the resource) has little effect on individual investment and extraction levels; and (3) the action-reaction feedback is fundamental in determining the success or failure of communities
Compensation temperatures and exchange bias in La1.5Ca0.5CoIrO6
We report on the study of magnetic properties of the La1.5Ca0.5CoIrO6 double
perovskite. Via ac magnetic susceptibility we have observed evidence of weak
ferromagnetism and reentrant spin glass behavior on an antiferromagnetic
matrix. Regarding the magnetic behavior as a function of temperature, we have
found that the material displays up to three inversions of its magnetization,
depending on the appropriate choice of the applied magnetic field. At low
temperature the material exhibit exchange bias effect when it is cooled in the
presence of a magnetic field. Also, our results indicate that this effect may
be observed even when the system is cooled at zero field. Supported by other
measurements and also by electronic structure calculations, we discuss the
magnetic reversals and spontaneous exchange bias effect in terms of magnetic
phase separation and magnetic frustration of Ir4+ ions located between the
antiferromagnetically coupled Co ions.Comment: 10 pages, 8 figures and supplemental materia
Testing the spectrum hypothesis of problematic online behaviors: A network analysis approach.
The validity of the constructs of problematic Internet or smartphone use and Internet or smartphone addiction has been extensively debated. The spectrum hypothesis posits that problematic online behaviors (POBs) may be conceptualized within a spectrum of related yet distinct entities. To date, the hypothesis has received preliminary support, and further robust empirical studies are still needed. The present study tested the spectrum hypothesis of POBs in an Australian community sample (n = 1,617) using a network analysis approach. Psychometrically validated self-report instruments were used to assess six types of POBs: problematic online gaming, cyberchondria, problematic cybersex, problematic online shopping, problematic use of social networking sites, and problematic online gambling. A tetrachoric correlation matrix was computed to explore relationships between online activities and a network analysis was used to analyze relationships between POBs. Correlations between online activities were positive and significant, but of small magnitude (0.051 ≤ r ≤ 0.236). The community detection analysis identified six distinct communities, corresponding to each POB, with strong relationships between items within each POB and weaker relationships between POBs. These findings provide further empirical support for the spectrum hypothesis, suggesting that POBs occur as distinct entities and with little overlap
Stochastic frontiers of efficiency for Brazilian investment funds: A panel data analysis
Foundations, methodological and empirical possibilities of measurement and analysis in the performance of financial investments within investment funds have been developed since they were once introduced in the 1970s, thus establishing a path of growing acceptance in financial markets and universities'' academies. The first approaches over the efficiency of these funds, considering their stochastic implications, occurred in the late 1990s and have evolved with the help of SFA - Stochastic Frontier Analysis, although it still needs more careful verification. This article measured and analyzed the stochastic frontier of efficiency over 33 different Brazilian investment funds from 2012 to 2015. For doing so, Battese and Coelli's (1995) specifications was used. It shows the effects of inefficiencies, which are defined as explicit functions of specific factors in the context of panel data funds. They are estimated by the maximum likelihood method. Sharpe ratios (SR) were also calculated for comparative purposes. Based on these two indicators (SFA and SR), the most recommendable funds to invest and the ones in which the application should not be performed were identified. Such procedures have stimulated the necessary and promising studies, as well as future researches, which, in turn, may establish new methodological formulation as an efficient and effective instrument to choose the best and the safest funds to invest
Identifying the psychological processes delineating non-harmful from problematic binge-watching: A machine learning analytical approach
As on-demand streaming technology rapidly expanded, binge-watching (i.e., watching multiple episodes of TV series back-to-back) has become a widespread activity, and substantial research has been conducted to explore its potential harmfulness. There is, however, a need for differentiating non-harmful and problematic binge-watching. This is the first study using a machine learning analytical strategy to further investigate the distinct psychological predictors of these two binge-watching patterns. A total of 4275 TV series viewers completed an online survey assessing sociodemographic variables, binge-watching engagement, and relevant predictor variables (i.e., viewing motivations, impulsivity facets, and affect). In one set of analyses, we modeled intensity of non-harmful involvement in binge-watching as the dependent variable, while in a following set of analyses, we modeled intensity of problematic involvement in binge-watching as the dependent variable. Emotional enhancement motivation, followed by enrichment and social motivations, were the most important variables in modeling non-harmful involvement. Coping/escapism motivation, followed by urgency and lack of perseverance (two impulsivity traits), were found as the most important predictors of problematic involvement. These findings indicate that non-harmful involvement is characterized by positive reinforcement triggered by TV series watching, while problematic involvement is linked to negative reinforcement motives and impulsivity traits
Static magnetic order of SrAOFeAs (A = Sc and V) revealed by local probes
Static magnetic order of quasi two-dimensional FeAs compounds
Sr4A2O6-xFe2As2, with A = Sc and V, has been detected by 57Fe Moessbauer and
muon spin relaxation ({\mu}SR) spectroscopies. The non-superconducting
stoichiometric (x = 0) A = Sc system exhibits a static internal/hyperfine
magnetic field both at the 57Fe and {\mu}+ sites, indicating antiferromagnetic
order of Fe moments below TN = 35 K with ~ 0.1 Bohr magneton per Fe at T = 2 K.
The superconducting and oxygen deficient (x = 0.4) A = V system exhibits a
static internal field only at the {\mu}+ site below TN ~ 40 K, indicating
static magnetic order of V moments co-existing with superconductivity without
freezing of Fe moments. These results suggest that the 42622 FeAs systems
belong to the same paradigm with the 1111 and 122 FeAs systems with respect to
magnetic behavior of Fe moments.Comment: 4 pages 4 figures: for information, contact
[email protected]
- …