600 research outputs found
Environmental and genetic influences on neurocognitive development: the importance of multiple methodologies and time-dependent intervention
Genetic mutations and environmental factors dynamically influence gene expression and developmental trajectories at the neural, cognitive, and behavioral levels. The examples in this article cover different periods of neurocognitive developmentâearly childhood, adolescence, and adulthoodâand focus on studies in which researchers have used a variety of methodologies to illustrate the early effects of socioeconomic status and stress on brain function, as well as how allelic differences explain why some individuals respond to intervention and others do not. These studies highlight how similar behaviors can be driven by different underlying neural processes and show how a neurocomputational model of early development can account for neurodevelopmental syndromes, such as autism spectrum disorders, with novel implications for intervention. Finally, these studies illustrate the importance of the timing of environmental and genetic factors on development, consistent with our view that phenotypes are emergent, not predetermined
Regulatory Taking: A Contract Approach
This Article begins by defining the parameters of the fifth amendment\u27s taking clause. The Article then reviews the various tests used in determining whether governmental action constitutes a taking, and discusses the recent Supreme Court decisions within the framework of case law as it has evolved since the Court\u27s 1922 landmark decision, Pennsylvania Coal Co. v. Mahon. Finally, the Article suggests a formula based on well-established contract principles for analyzing the impact of land use regulation on private property interests
Modelo de cabalgamiento profundo para el Alto Atlas (Marruecos). Implicaciones sĂsmicas en la zona de colisiĂłn entre Eurasia y Africa
Previous crustal models of the High Atlas suppose the existence of a mid-crustal detachment where all the surface thrusts merged and below which the lower crust was continuous. However, both seismic refraction data and gravity modeling detected a jump in crustal thickness between the High Atlas and the northern plains. Here we show that this rapid and vertical jump in the depth of Moho discontinuity suggests that a thrust fault may penetrate the lower crust and offset the Moho (deep-rooted âthick skinnedâ model). The distribution of Neogene and Quaternary volcanisms along and at the northern part of the High Atlas lineament can be related to the beginning of a partial continental subduction of the West African plate to the north underneath Moroccan microplate. Allowing from the complex problem of the plate boundary in the western zone of the Mediterranean, we propose to interpret the South-Atlasic fault zone as the actual northwestern boundary of the stable part of the African plate rather than the Azores-Gibraltar fault currently used.Los modelos geodinĂĄmicos existentes sobre la estructura profunda del alto Atlas suponen la existencia de un despegue medio-cortical donde convergen los cabalgamientos superficiales y bajo el cual la corteza inferior es continua. Los datos de sĂsmica de refracciĂłn y gravimetrĂa, sin embargo, indican la existencia de una discontinuidad en el grosor de la corteza (profundidad del Moho) bajo el Alto Atlas. En este artĂculo ponemos de manifiesto que este salto rĂĄpido en la profundidad del Moho puede ser causado por un cabalgamiento que penetra la corteza inferior, desplazando la base de la misma (âdeeprooted thick skinned modelâ). La distribuciĂłn del volcanismo NeĂłgeno y Cuaternario a lo largo de y al norte de la alineaciĂłn del Alto Atlas pueden estar relacionados con el comienzo de una subducciĂłn continental parcial de la placa Africana occidental hacia el norte, bajo la microplaca marroquĂ. La expresiĂłn en superficie de este cabalgamiento, la zona de falla sud-atlĂĄsica, refleja la influencia de una sutura continental heredada de orogenias anteriores (panafricana, hercĂnica y rifting JurĂĄsico). Por tanto, proponemos que este frente heredado representa el lĂmite meridional de la zona de colisiĂłn mediterrĂĄnea y el margen noroccidental de la porciĂłn estable de la placa africana
Effets de scenarios de changements climatiques sur la cacaoculture en Cote dâIvoire
Lâinfluence des scenarios de changements climatiques a Ă©tĂ© analysĂ©e pour les rĂ©gions Centre et Sud de production cacaoyĂšre en CĂŽte dâIvoire. A partir des modĂšles RCP 4.5 et 8.5 de concentration des Gaz Ă Effets de Serre (GES), les paramĂštres tempĂ©rature et pluviomĂ©trie ont Ă©tĂ© projetĂ©s sur les horizons 2021-2050 et 2041-2070 en comparaison Ă la pĂ©riode de rĂ©fĂ©rence 1980-2010. Les rĂ©sultats ont montrĂ© quâen dehors du nombre Ă©levĂ© de jours chauds qui pourrait provoquer la disparition de la cacaoculture dans les zones marginales de la rĂ©gion Centre, les indices climatiques se situent dans des conditions normales de production du cacaoyer dans les deux rĂ©gions. Les risques liĂ©s aux maladies et ravageurs pourraient ĂȘtre similaires ou potentiellement rĂ©duits. En rĂ©gion Sud, les variations climatiques nâauraient aucun impact sur la cacaoculture. Comme stratĂ©gies de rĂ©silience, les programmes de sĂ©lection variĂ©tale devront mettre Ă la disposition des producteurs un matĂ©riel vĂ©gĂ©tal tolĂ©rant Ă la sĂ©cheresse et aux maladies accompagnĂ©e de formations sur les bonnes pratiques agricoles dont lâagroforesterie. Toutefois, lâaccĂšs des producteurs Ă lâinformation mĂ©tĂ©orologique devra ĂȘtre renforcĂ©.
English title: Climate change effects in cocoa cultivation
Abstract
The influence of climate change scenarios was analyzed for the Center and South regions of cocoa farming in CĂŽte dâIvoire. From greenhouse gas (GHG) concentration models RCP 4.5 and 8.5, the parameters of temperature and rainfall were projected over the time in years 2021-2050 and 2041- 2070 compared to year 1980-2010 as reference period. The results showed that apart from the high number of hot days which could cause the disappearance of cocoa farming in marginal areas of the Center region, the climatic indices are normal within cocoa production conditions in both regions. Risks on cocoa pests and disease could be similar or potentially reduced. In the South region, climatic variations would have no impact on cocoa farming. As resilience adaptation strategies, tolerant germplasm to drought and pest and disease should be provided to farmers by cocoa research program with training package on good agricultural practices (GAP) including agroforestry. Therefore, theaccess to meteorological information has to be strengthened for smallholders cocoa farmers.
Key words: Climate change scenarios, impact, cocoa farming, CĂŽte dâIvoire
Integrate and Fire Neural Networks, Piecewise Contractive Maps and Limit Cycles
We study the global dynamics of integrate and fire neural networks composed
of an arbitrary number of identical neurons interacting by inhibition and
excitation. We prove that if the interactions are strong enough, then the
support of the stable asymptotic dynamics consists of limit cycles. We also
find sufficient conditions for the synchronization of networks containing
excitatory neurons. The proofs are based on the analysis of the equivalent
dynamics of a piecewise continuous Poincar\'e map associated to the system. We
show that for strong interactions the Poincar\'e map is piecewise contractive.
Using this contraction property, we prove that there exist a countable number
of limit cycles attracting all the orbits dropping into the stable subset of
the phase space. This result applies not only to the Poincar\'e map under
study, but also to a wide class of general n-dimensional piecewise contractive
maps.Comment: 46 pages. In this version we added many comments suggested by the
referees all along the paper, we changed the introduction and the section
containing the conclusions. The final version will appear in Journal of
Mathematical Biology of SPRINGER and will be available at
http://www.springerlink.com/content/0303-681
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Operationalising and measuring language dominance
The paper offers a new way to measure language ability in bilinguals, based on measures of lexical richness. The validity of proposed approach is tested in a variety of ways
Differential habituation to repeated sounds in infants at high risk for autism
It has been suggested that poor habituation to stimuli might explain atypical sensory behaviours in autism, i.e. over-responsiveness to some stimuli and under-sensitivity to other. We investigated habituation to repeated sounds using an oddball paradigm in 9 month-old infants with an older sibling with autism and hence at high risk for developing autism. Auditory evoked responses to repeated sounds in control infants (at low risk of developing autism) decreased over time, demonstrating habituation, and their responses to deviant sounds were larger than responses to standard sounds, indicating discrimination. In contrast, neural responses in infants at high risk showed no habituation, and reduced sensitivity to changes in frequency. Reduced sensory habituation may be present at a younger age than the emergence of autistic behaviour in some individuals, and we propose that this could play a role in the sensory atypicalities observed in autism
Atypical audiovisual speech integration in infants at risk for autism
The language difficulties often seen in individuals with autism might stem from an inability to integrate audiovisual information, a skill important for language development. We investigated whether 9-month-old siblings of older children with autism, who are at an increased risk of developing autism, are able to integrate audiovisual speech cues. We used an eye-tracker to record where infants looked when shown a screen displaying two faces of the same model, where one face is articulating/ba/and the other/ga/, with one face congruent with the syllable sound being presented simultaneously, the other face incongruent. This method was successful in showing that infants at low risk can integrate audiovisual speech: they looked for the same amount of time at the mouths in both the fusible visual/ga/â audio/ba/and the congruent visual/ba/â audio/ba/displays, indicating that the auditory and visual streams fuse into a McGurk-type of syllabic percept in the incongruent condition. It also showed that low-risk infants could perceive a mismatch between auditory and visual cues: they looked longer at the mouth in the mismatched, non-fusible visual/ba/â audio/ga/display compared with the congruent visual/ga/â audio/ga/display, demonstrating that they perceive an uncommon, and therefore interesting, speech-like percept when looking at the incongruent mouth (repeated ANOVA: displays x fusion/mismatch conditions interaction: F(1,16) = 17.153, p = 0.001). The looking behaviour of high-risk infants did not differ according to the type of display, suggesting difficulties in matching auditory and visual information (repeated ANOVA, displays x conditions interaction: F(1,25) = 0.09, p = 0.767), in contrast to low-risk infants (repeated ANOVA: displays x conditions x low/high-risk groups interaction: F(1,41) = 4.466, p = 0.041). In some cases this reduced ability might lead to the poor communication skills characteristic of autism
On Hilberg's Law and Its Links with Guiraud's Law
Hilberg (1990) supposed that finite-order excess entropy of a random human
text is proportional to the square root of the text length. Assuming that
Hilberg's hypothesis is true, we derive Guiraud's law, which states that the
number of word types in a text is greater than proportional to the square root
of the text length. Our derivation is based on some mathematical conjecture in
coding theory and on several experiments suggesting that words can be defined
approximately as the nonterminals of the shortest context-free grammar for the
text. Such operational definition of words can be applied even to texts
deprived of spaces, which do not allow for Mandelbrot's ``intermittent
silence'' explanation of Zipf's and Guiraud's laws. In contrast to
Mandelbrot's, our model assumes some probabilistic long-memory effects in human
narration and might be capable of explaining Menzerath's law.Comment: To appear in Journal of Quantitative Linguistic
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