1,249 research outputs found
Coupled complex Ginzburg-Landau systems with saturable nonlinearity and asymmetric cross-phase modulation
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)
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
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
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
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
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)
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
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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