R E S U M OA variabilidade dos atributos químicos do solo é influenciada por complexas interações entre os fatores e os processos de formação do solo. Este trabalho partiu da hipótese de que os atributos químicos do solo variam com o microrrelevo a ponto de alterar as recomendações de manejo para uso agrícola. Com isto, o relevo foi separado em compartimentos e as superfícies estudadas com o objetivo de se determinar os atributos químicos do solo, avaliar a distribuição e a dependência espacial desses atributos. A grade amostral compreendeu uma área de 102 ha da Fazenda Agrícola Famosa, localizada na Chapada do Apodi, CE. O solo da área apresenta origem calcária e as amostras foram coletadas em 92 pontos distanciados 200 m na linha e 100 m entre linhas, nas profundidades de 0-20 e 20-40 cm. Com os dados, gerou-se um modelo de elevação do terreno e, com base nas formas de relevo identificadas, dividiu-se o local de estudo em superfícies. Os dados foram avaliados por estatística descritiva e análise de variabilidade espacial, com base no ajuste de semivariogramas e mapas de krigagem. Os atributos químicos do solo apresentaram variabilidade espacial nos microrrelevos convexo, retilíneo e côncavo, intensificada pelo fluxo de água nas profundidades. Spatial variability of soil chemical attributes associated with microrelief A B S T R A C TThe variability of soil chemical attributes is influenced by complex interactions between factors and processes of soil formation. This study hypothesized that soil chemical attribute varies with microrelief to change management recommendations for agricultural use. The relief was separated in compartments and surfaces were studied with the objective to determine the soil chemical properties and to evaluate the spatial dependence of these attributes. Sampling grid was established in an area of 102 ha at Agricultural Farm Famosa localized in Plateau of Apodi, CE. The soil was derived from limestone and was collected at 92 points spaced at 200 by 100 m and in 0-20 and 20-40 cm depths. With the topographic data a terrain modeling was generated and based on the identified microrelief, the study site was divided into surfaces. Data were analysed using descriptive statistics and spatial variability analysis, with the semivariograms adjustments and kriging maps. Soil chemical attributes showed spatial variability at the convex, concave and rectilinear microrelief, being intensified by water flow at the depths.

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Extensive literature has demonstrated that arousal and fear modify memory acquisition and consolidation. Predator hair and odors increase arousal in rats and, therefore, may influence information encoding and synaptic plasticity in the rodent nervous system. In behavioral experiments, we confirm that laboratory-bred Long Evans rats avoid cat hair. Electrophysiological work in vivo showed that long-term potentiation (LTP) in the dentate gyrus induced by perforant path stimulation was enhanced for 5-7 days when LTP induction occurred in the presence of cat hair relative to fake hair. The muscarinic receptor antagonist scopolamine (i.p.) reversed the cat hair-elicited LTP enhancement without affecting weaker LTP elicited in the presence of fake hair. Thus, exposure to a predator stimulus elicits a cholinergically-dependent state of heightened plasticity that may serve to facilitate information storage in hippocampal circuits.Memory formation is a dynamic and selective process, and the attentional selection and subsequent encoding of stimuli in memory systems are influenced by emotional arousal and stress (e.g., McGaugh 2000McGaugh , 2004Vuilleumier 2005;LeBar and Cabeza 2006). In several species, including humans, acute increases in arousal and related adrenal hormones can enhance the consolidation of stimuli experienced in close temporal proximity to the hormonal activation, leading to stronger encoding of emotionally arousing material relative to more neutral stimuli (Cahill et al. , 2000McGaugh 2000;McGaugh and Roozendaal 2002).Extensive evidence suggests that the effect of arousal to facilitate memory consolidation is mediated by the basolateral amygdala. Local, intra-amygdala application of arousal-related pharmacological agents (e.g., adrenergic, noradrenergic, or glucocorticoid agonists) can enhance memory consolidation, while lesions of the basolateral amygdala block arousal-induced memory modulation (Packard et al. 1994;Cahill and McGaugh 1998;McGaugh 2004). Further, the amygdala also influences synaptic plasticity in several forebrain systems, with electrical activation of amygdala neurons enhancing long-term potentiation (LTP) at hippocampal, thalamocortical, and corticostriatal synapses (Akirav and Richter-Levin 1999;Frey et al. 2001;Dringenberg et al. 2004;Popescu et al. 2007). Thus, the basolateral amygdala serves as a critical interface linking arousal states, plasticity mechanisms, and memory consolidation (Cahill and McGaugh 1998;Paré 2003;McGaugh 2004;LeBar and Cabeza 2006).Here, we tested whether an innately arousing and aversive stimulus, cat hair (Dielenberg and McGregor 2001;Apfelbach et al. 2005), is effective in modulating hippocampal LTP in rats under in vivo conditions. Further, given the role of acetylcholine (ACh) in mediating arousal-and amygdala-induced memory consolidation and plasticity (Frey et al. 2001;Dringenberg et al. 2004;McGaugh 2004) All experimental procedures were conducted in accordance with the guidelines of the Canadian Council on Animal Care and approved by the Queen's...

RESUMO -A Chapada do Apodi caracteriza-se como importante pólo agrícola no estado do Ceará. Apesar da homogeneidade de clima, relevo e material de origem, seus solos apresentam grande variabilidade de atributos, muitas vezes em pequenas escalas espaciais, indicando a necessidade de manejos distintos. O presente trabalho teve como objetivo estudar a influência do microrrelevo na variabilidade espacial das diferentes frações granulométricas dos solos da Chapada do Apodi. Para isso, foi realizado levantamento planialtimétrico em uma área de 102 ha, seguido de tradagens para coleta das amostras de solo e determinação da profundidade efetiva. As amostras foram submetidas à análise granulométrica e os dados foram tratados por meio da estatística descritiva e da geoestatística, utilizando-se semivariogramas e mapas de krigagem. Com base nas formas de microrelevo, o local de estudo foi compartimentado em 03 superfícies distintas (côncava, convexa e retilínea). Por meio dos resultados foi identificada clara influência do microrrelevo na distribuição das frações granulométricas. Maiores teores de argila e maiores profundidades de solos foram encontrados na superfície côncava. Estes resultados são indicativos de maior ação da pedogênese nos solos desta porção do terreno em resposta à existência de fluxos hídricos convergentes. A ocorrência de maiores teores de areia e solos mais rasos na superfície convexa e mais elevada indica menor ação da pedogênese e maior intensidade do processo de erosão seletiva. O uso da geoestatística contribuiu para a identificação de áreas com necessidades diferenciadas de manejo, servindo como importante ferramenta para a tomada de decisões, especialmente relacionadas à irrigação. Palavras-chave:Chapada do Apodi. Variabilidade Espacial. Microtopografia. Solos-análise. ABSTRACT -The Apodi Plateau is characterized as an important agricultural centre for the state of Ceará, Brazil. Despite the homogeneity of climate, topography and parent material, soils in the area exhibit a great variability in attributes, often on small spatial scales, indicating the need for separate managements systems. The aimed of the present work was to investigate the influence of microrelief on the spatial variability of different particle-size fractions of the soils in the Apodi Plateau. A plano-altimetric survey was conducted in an area of 102 ha, followed by boreholes for collecting soil samples and determining the effective depth. The samples were subjected to particle-size analysis and the data processed with descriptive statistics and geostatistics, using semivariograms and kriging charts. Based on the microrelief, the study area was divided into 3 different surfaces (concave, convex and flat). From the results a clear influence of the microrelief on the distribution of the particle-size fractions was identified. Higher clay-content and greater soil depth were found on the concave surface. These results indicate greater soil-genesis activity in the soils of this area in response to the existing convergent water flo...

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