1,249 research outputs found

    Coupled complex Ginzburg-Landau systems with saturable nonlinearity and asymmetric cross-phase modulation

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    We formulate and study dynamics from a complex Ginzburg-Landau system with saturable nonlinearity, including asymmetric cross-phase modulation (XPM) parameters. Such equations can model phenomena described by complex Ginzburg-Landau systems under the added assumption of saturable media. When the saturation parameter is set to zero, we recover a general complex cubic Ginzburg-Landau system with XPM. We first derive conditions for the existence of bounded dynamics, approximating the absorbing set for solutions. We use this to then determine conditions for amplitude death of a single wavefunction. We also construct exact plane wave solutions, and determine conditions for their modulational instability. In a degenerate limit where dispersion and nonlinearity balance, we reduce our system to a saturable nonlinear Schr\"odinger system with XPM parameters, and we demonstrate the existence and behavior of spatially heterogeneous stationary solutions in this limit. Using numerical simulations we verify the aforementioned analytical results, while also demonstrating other interesting emergent features of the dynamics, such as spatiotemporal chaos in the presence of modulational instability. In other regimes, coherent patterns including uniform states or banded structures arise, corresponding to certain stable stationary states. For sufficiently large yet equal XPM parameters, we observe a segregation of wavefunctions into different regions of the spatial domain, while when XPM parameters are large and take different values, one wavefunction may decay to zero in finite time over the spatial domain (in agreement with the amplitude death predicted analytically). While saturation will often regularize the dynamics, such transient dynamics can still be observed - and in some cases even prolonged - as the saturability of the media is increased, as the saturation may act to slow the timescale.Comment: 36 page

    Características estratigráficas y sedimentológicas del "Garumniense" en el sector de Ager (Pre-Pirineo, Lleida)

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    The depositional sequences of the Paleogene non-marine deposits in the Ager basin show the vertical succession of lacustrine sediments (Massana Formation), fluvial and floodplain deposits (Figuerola Fm), basin-wide lacustrine sediments (Milla Fm) and different successions of lacustrine-palustrine, floodplain, fluvial, sabkha and tidal deposits (Perauba Complex). These different sedimentary environments where developed during Upper Maastrichtian-Lower Paleogene time span. The fossil assemblages suggest that the K/T event occurred during the sedimentation of one of these sedimentary environments. Formerly it was assumed that the KJí boundary event was strictly related to a particular carbonate leve1 (Milla Fm), but now this event is related to the deposition of floodplain and fluvial sediments at the Upper portion of the Figuerola Fm. Accordingly with the new paleomagnetic and paleontologic data, the disappearance of the cretaceous charophytes and dinosaurs seems to have occurred in the studied area about two million years before K/T boundary event

    El rol de la clase social, la educación y el desempleo parentales en el desarrollo cognitivo infantil

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    Objective: Assessing the association between socioeconomic gradient and cognitive development among children of a Spanish birth cohort aged 5-6 years from a gender perspective. Method: Cognitive development was assessed on 525 children aged 5-6 years in the INMA-Valencia cohort, with the Global Cognitive Score (GCS) from McCarthy Scales of Children’s Abilities. Information on social class, education level and employment was collected for both parents in addition to other sociodemographic factors, parental, family and child characteristics. The relationship between maternal and paternal socioeconomic gradient and cognitive development was assessed by linear regressions and comparing the variance explained by each indicator measured in the mother and father. Results: Maternal socioeconomic gradient indicators explained more variance on GCS than paternal. Maternal education and paternal social class had an important individual effect that stayed after adjusting by other parental, child and family determinants. In the multivariable analysis, maternal education, age and intelligence, paternal social class and the child’s age and sex were significantly associated with cognitive development. Conclusions: Diverse socioeconomic gradient factors have an important influence on cognitive development, maternal education being the strongest determinant. Policies should be implemented to mitigate the negative effects of this gradient on child development.Objetivo: Evaluar la asociación del gradiente socioeconómico y el desarrollo cognitivo en ni˜nos y ni˜nas de una cohorte espa˜nola a los 5-6 a˜nos de edad desde una perspectiva de género. Método: Se evaluó el desarrollo cognitivo en 525 ni˜nos/as de 5-6 a˜nos de la cohorte INMA-Valencia, mediante la Puntuación Global Cognitiva (PGC) de las Escalas McCarthy para ni˜nos y ni˜nas. Se recogió información de ambos progenitores sobre clase social, nivel de estudios y empleo, además de otros factores sociodemográficos, características parentales, de la familia y del ni˜no o la ni˜na. La relación entre el gradiente socioeconómico materno y paterno y el desarrollo cognitivo se evaluó mediante modelos de regresión lineal y comparando la varianza explicada por cada uno de los indicadores medidos en la madre y en el padre. Resultados: Los indicadores de gradiente socioeconómico de la madre explicaron más varianza del índice de PGC que los del padre. La educación materna y la clase social paterna tuvieron un importante efecto individual, que se mantuvo tras ajustar por otros determinantes de los progenitores, del ni˜no o de la ni˜na, y del entorno familiar. En el análisis multivariante, la educación, la edad y la inteligencia maternas, la clase social paterna, y la edad y el sexo del infante se asociaron significativamente con el desarrollo cognitivo. Conclusiones: Distintos factores del gradiente socioeconómico tienen influencia en el desarrollo cognitivo, siendo la educación materna el determinante más fuerte. Deberían implementarse políticas para paliar los efectos negativos de este gradiente en el desarrollo infantil

    Molecular codes defining rostrocaudal domains in the embryonic mouse hypothalamus

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    The prosomeric model proposes that the hypothalamus is a rostral forebrain entity, placed ventral to the telencephalon and rostral to the diencephalon. Gene expression markers differentially label molecularly distinct dorsoventral progenitor domains, which represent continuous longitudinal bands across the hypothalamic alar and basal regions. There is also circumstantial support for a rostrocaudal subdivision of the hypothalamus into transverse peduncular (caudal) and terminal (rostral) territories (PHy, THy). In addition, there is evidence for a specialized acroterminal domain at the rostral midline of the terminal hypothalamus (ATD). The PHy and THy transverse structural units are presently held to form part of two hypothalamo-telencephalic prosomeres (hp1 and hp2, respectively), which end dorsally at the telencephalic septocommissural roof. PHy and THy have distinct adult nuclei, at all dorsoventral levels. Here we report the results of data mining from the Allen Developing Mouse Brain Atlas database, looking for genes expressed differentially in the PHy, THy and ATD regions of the hypothalamus at several developmental stages. This search allowed us to identify additional molecular evidence supporting the postulated fundamental rostrocaudal bipartition of the mouse hypothalamus into the PHy and THy, and also corroborated molecularly the singularity of the ATD. A number of markers were expressed in Thy (Fgf15, Gsc, Nkx6.2, Otx1, Zic1/5), but were absent in PHy, while other genes showed the converse pattern (Erbb4, Irx1/3/5, Lmo4, Mfap4, Plagl1, Pmch). We also identified markers that selectively label the ATD (Fgf8/10/18, Otx2, Pomc, Rax, Six6). On the whole, these data help to explain why, irrespective of the observed continuity of all dorsoventral molecular hypothalamic subdivisions across PHy and THy, different nuclear structures originate within each of these two domains, and also why singular structures arise at the ATD, e.g., the suprachiasmatic nuclei, the

    Bringing “Behavioral” Fully Into Behavioral Public Administration

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    Behavioral economics is an increasingly influential field across the social sciences, including public administration. But while some behavioral economics ideas have spread rapidly in public administration research, we argue that a broader range of behavioral economics concepts can and should be applied. We begin by outlining some central models and concepts from behavioral economics to fix ideas, including the rational model and the “behavioral” response. We then discuss how a variety of heretofore underutilized behavioral economics concepts can be applied to a specific area of work in public administration – bureaucratic decision making. Our aim in doing so is two-fold. First, we hope to provide fresh food for thought for researchers and practitioners working in the broader behavioral public administration space. Second, we hope to demonstrate that there is substantial scope for expanding behavioral economics’ influence on public administration research

    A characterization of finite multipermutation solutions of the Yang–Baxter equation

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    We prove that a finite non-degenerate involutive set-theoretic solution (X, r) of the Yang–Baxter equation is a multipermutation solution if and only if its structure group G(X, r) admits a left ordering or equivalently it is poly-Z.We prove that a finite non-degenerate involutive set-theoretic solution (X, r) of the Yang–Baxter equation is a multipermutation solution if and only if its structure group G(X, r) admits a left ordering or equivalently it is poly-Z

    Internal anatomy of an erg sequence from the aeolian-fluvial system of the De La Cuesta Formation (Paganzo Basin, northwestern Argentina)

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    Permian red beds of the De La Cuesta Formation in the Sierra de Narváez (Paganzo Basin, northwestern Argentina) are essentially composed of sandstones associated with mudstones and subordinate conglomerates. Facies distributions and stacking patterns indicate that these sediments resulted from the interaction between aeolian and ephemeral fluvial systems, and are represented by aeolian dune, dry aeolian interdune and Aeolian sand sheet, mudflat, wet aeolian interdune, and fluvial deposits. The De La Cuesta Formation is characterized by aeolian (erg) sequences alternating with non-aeolian (terminal alluvial fan - mudflat) sequences. Each erg sequence is bounded at its base by a regionally extensive sand-drift surface and at the top by an extinction surface. A number of architectural elements, including aeolian dunes limited by interdunes, grouped crescentic Aeolian dunes, longitudinal dunes, and draa with superimposed crescentic dunes are recognised in the erg sequences. The sand sea developed during phases of increasing aridity, whereas non-aeolian deposition might have occurred during more humid phases. Thus, the styles of aeolian-fluvial interaction are considered to result from cyclical climatic changes. Within the drier hemicycles, the rhythmic alternation between draa deposits and aeolian dune and interdune deposits indicates higher frequency cycles that could be attributed to subtle climatic oscillations and/ or changes in sand supply and availability. The development of the Permian sand sea in the inland Paganzo Basin seems to be related to the growth of a volcanic chain to the west. This topographic barrier separated the Paganzo Basin from the Chilean Basin, located along the western margin of Gondwana and characterised by shallow marine carbonate sedimentation. The correlation between the Permian erg and the shallow marine carbonates suggests a regional warming period during the Middle Permian in western Gondwana

    Deep model simulation of polar vortices in gas giant atmospheres

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    The Cassini and Juno probes have revealed large coherent cyclonic vortices in the polar regions of Saturn and Jupiter, a dramatic contrast from the east-west banded jet structure seen at lower latitudes. Debate has centered on whether the jets are shallow, or extend to greater depths in the planetary envelope. Recent experiments and observations have demonstrated the relevance of deep convection models to a successful explanation of jet structure and cyclonic coherent vortices away from the polar regions have been simulated recently including an additional stratified shallow layer. Here we present new convective models able to produce long-lived polar vortices. Using simulation parameters relevant for giant planet atmospheres we find flow regimes that are in agreement with geostrophic turbulence (GT) theory in rotating convection for the formation of large scale coherent structures via an upscale energy transfer fully three-dimensional. Our simulations generate polar characteristics qualitatively similar to those seen by Juno and Cassini: they match the structure of cyclonic vortices seen on Jupiter; or can account for the existence of a strong polar vortex extending downwards to lower latitudes with a marked spiral morphology and the hexagonal pattern seen on Saturn. Our findings indicate that these vortices can be generated deep in the planetary interior. A transition differentiating these two polar flows regimes is described, interpreted in terms of different force balances and compared with previous shallow atmospheric models which characterised polar vortex dynamics in giant planets. In addition, the heat transport properties are investigated confirming recent scaling laws obtained in the context of reduced models of GT.Comment: 18 pages, 13 figures and 3 table
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