766 research outputs found
The response of taxonomic and functional diversity of the seed bank to agricultural intensification and soil properties in two Mediterranean cereal areas
Weed seed bank diversity has been severely impacted by agriculture intensifi cation.
However, the functional consequences have been poorly studied in highly intensifi ed
agro-ecosystems.Postprint (published version
The identity of the nursing academic : between education and research
This study aimed to analyze how nurses represent their role as nursing academics and their conceptions, strategies and feelings involved in teaching-learning and research in nursing. A qualitative study was conducted. To achieve this goal, a semi-structured interview was carried out with seven nurses who worked as teachers and researchers at a university in Barcelona, Spain. The data were analyzed through categories validated in a previous study with the support of The Atlas Ti program. The results evidenced that nurses are less equipped to develop the researcher role, and that the profession is not justified without a close relationship between nursing theory and practice. The nursing academics look for a balance between teaching and research and they also wish to promote the development of models and theories in their own discipline.O estudo teve como objetivo analisar como as enfermeiras representam seu papel como acadêmicas de enfermagem, suas concepções, suas estratégias e seus sentimentos envolvidos nos processos de ensino-aprendizagem e pesquisa na enfermagem. Realizou-se uma pesquisa qualitativa. A coleta de dados foi através da entrevista semiestruturada aplicada a sete enfermeiras que trabalham como docentes e pesquisadoras em uma universidade de Barcelona, Espanha. Os dados foram analisados através de categorias validadas em um estudo anterior com o apoio do programa de ATLAS ti. Os resultados evidenciarem que as enfermeiras sentem-se menos preparadas para desenvolver o papel de investigadoras e que a profissão não se justifica sem uma estreita relação entre a teoria e a prática de enfermagem. As acadêmicas de enfermagem buscam equilíbrio entre a docência e a pesquisa e sentem-se desafiadas a desenvolver teorias e modelos em sua disciplina.El estudio tuvo como objetivo analizar cómo las enfermeras representan su rol como académicos de enfermería, sus concepciones, sus estrategias y los sentimientos involucrados en los procesos de enseñanza y aprendizaje e investigación en la enfermería. Se realizó un estudio cualitativo, y la recolección de datos fue a través de una entrevista semi-estructurada a siete enfermeras que trabajan como docentes e investigadoras en una universidad de Barcelona, España. Los datos se analizaron a través de categorías validadas en un estudio anterior con el apoyo del programa Atlas Ti. Los resultados evidenciaron que las enfermeras se sienten menos preparadas para desarrollar el rol de investigador, y que la profesión no se justifica sin una estrecha relación entre la teoría y la práctica de la enfermería. Los académicos de enfermería buscan un equilibrio entre la docencia y la investigación y se sienten desafiadas a desarrollar teorías y modelos en su propia disciplina
The Kibble-Zurek mechanism in a subcritical bifurcation
We present the study of the freezing dynamics of topological defects in a subcritical system by testing the Kibble-Zurek (KZ) mechanism while crossing a tri-stable region in a one-dimensional quintic complex Ginzburg-Landau equation. The critical exponents of the KZ mechanism and the horizon (KZ-scaling regime) are predicted from the quasistatic study, and are in full accordance with the quenched study. The correlation length, in the KZ freezing regime, is corroborated from the number of topological defects and from the spatial correlation function of the order parameter. Furthermore, we characterize the dynamics to differentiate three out-of-equilibrium regimes: the adiabatic, the impulse and the free-relaxation. We show that the impulse regime shares a common temporal domain with a fast exponential increase of the order parameter
Activitats formadores programades i competències adquirides
projecte: 2014PID-UB/073El present projecte se centra en analitzar amb profunditat el funcionament, organització i resultats, en termes de rendiment i de adquisició de competències transversals, de les activitats formadores programades en 5 grups de l’assignatura de Política Econòmica d’Espanya i la Unió Europea.
Les activitats són quatre: a) l’elaboració de mapes conceptuals (individual i/o en equip en funció de la grandària del grup) de documents i articles bàsics de la bibliografia recomanada; b) la redacció individual d’un document de reflexió curt; c) la confecció d’un treball en equip i d) la prova final de síntesi.
En la primera i segona fases del procés cadascuna de les activitats ha estat configurada en el campus com una tasca, i s’han modificat i re-definit els instruments plantejats per realitzar-la i avaluar-la amb el corresponent feedback, amb la participació dels estudiants en el disseny de les rubriques per l’avaluació i la identificació i puntuació de les competències transversals adquirides.
En la tercera i quarta fases la intervenció s’ha centrat en la remodelació de la activitat “elaboració del mapa conceptual” utilizant la metodologia de l’aprenentatge per indagació (IBL), tot introduint les innovacions més complexes en dos grups concrets, als quals, per les seves dimensions, ha estat possible implicar més als estudiants en el procediment de co-disseny.
Els resultats previstos són molt semblants als assolits, excepte el d’aconseguir el co-disseny de la rubrica final per l’avaluació, ja que degut a manca material de temps no ha estat viable la participació dels estudiants en aquest darrer instrument.Codi del projecte: 2014PID-UB/07
Exploring the Kibble-Zurek mechanism in a secondary bifurcation
We present new experimental results on the quenching dynamics of an extended thermo-convective system (a network array of approximately 100 convective oscillators) going through a secondary subcritical bifurcation. We characterize a dynamical phase transition through the nature of the domain walls (1D-fronts) that connect the basic multicellular pattern with the new oscillating one. Two different mechanisms of the relaxing dynamics at the threshold are characterized depending on the crossing rate of the quenched transition. From the analysis of fronts, we show that these mechanisms follow different correlation length scales . Below a critical value , a slow response dynamics yields a spatiotemporal coherent front with weak coupling between oscillators. Above , for rapid quenches, defects are trapped at the front with a strong coupling between oscillators, similarly to the Kibble-Zurek mechanism in quenched phase transitions. These defects, pinned to the fronts, yield a strong decay of the correlation length
Frozen dynamics and synchronization through a secondary symmetry-breaking bifurcation
We show evidence of the frozen dynamics (Kibble-Zurek mechanism) at the transition one-dimensional (1D) front of an extended 1D array of convective oscillators that undergo a secondary subcritical bifurcation. Results correspond to a global synchronization process from nonlocal coupling between the oscillating units. The quenched dynamics exhibits defect trapping at the synchronization front according to the Kibble-Zurek mechanism, predicted for condensed matter systems. A stronger subcriticality prevents the fronts from freezing defects during the quenched transitions. A synchronization model of supercritical oscillating units is proposed to explain differentiation mechanisms in morphogenesis above a critical crossing rate when the frequency of the individual oscillators becomes coherent. The phases of such oscillators are spatially coupled through a Kuramoto-Battogtokh term that leads to the experimentally observed subcriticality. As a consequence, we show that the Kibble-Zurek mechanism overcomes non-locality of a geometrical network above a critical crossing rate
Weed seed bank diversity in dryland cereal fields: does it differ along the field and between fields with different landscape structure?
n this work, we aimed to test whether taxonomic diversity and functional diversity andthe values of functional traits of the weed seed bank varied across the field, from margins to thecore, and between fields embedded in distinct landscape structures. We sampled the seed bank of 47 conventionally managed cereal fields from two Mediterranean regions in SpainThis work was funded by FEDER (European Regional Development Funds) and the Spanish Ministry
of Economy and Competitiveness grants (projects AGL2012-33736 and AGL2015-64130-R). Y.P. was supported by
an FPI scholarship (Spanish Ministry of Economy and CompetitivenessPostprint (published version
Large Language Models as General Pattern Machines
We observe that pre-trained large language models (LLMs) are capable of
autoregressively completing complex token sequences -- from arbitrary ones
procedurally generated by probabilistic context-free grammars (PCFG), to more
rich spatial patterns found in the Abstraction and Reasoning Corpus (ARC), a
general AI benchmark, prompted in the style of ASCII art. Surprisingly, pattern
completion proficiency can be partially retained even when the sequences are
expressed using tokens randomly sampled from the vocabulary. These results
suggest that without any additional training, LLMs can serve as general
sequence modelers, driven by in-context learning. In this work, we investigate
how these zero-shot capabilities may be applied to problems in robotics -- from
extrapolating sequences of numbers that represent states over time to complete
simple motions, to least-to-most prompting of reward-conditioned trajectories
that can discover and represent closed-loop policies (e.g., a stabilizing
controller for CartPole). While difficult to deploy today for real systems due
to latency, context size limitations, and compute costs, the approach of using
LLMs to drive low-level control may provide an exciting glimpse into how the
patterns among words could be transferred to actions.Comment: 21 pages, 25 figures. To appear at Conference on Robot Learning
(CoRL) 202
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