Evolução morfotectônica do maciço estrutural pereiro, província Borborema

The Northeast relief was described by the Pediplanation Model. This action discards the theoretical basis of post-Cretaceous tectonic evolution of the landscape. Through this model the Massif Pereiro - MP, Borborema Province, was established as part of the Tablelands Area Residual Sertanejos. The present work aims to establish the post- Cretaceous morphotectonic evolution of the MP by geomorphological and geological mapping using Geographic Information System, Remote Sensing and dating of sediments by Single Aliquot Regenerative-dose (SAR). The MP is contained in the core semi-arid, annual precipitation of 600-800 mm / year. The MP is NE-SW, is limited by Shear Zone Jaguaribe (ZCJ) and Portalegre Shear Zone (ZCPa), the same attitude, and crossed by several other shear zones. These shear zones show evidence of brittle Cenozoic reactivation, mostly as normal faults and shallow crustal level. The Quaternary sedimentation around the MP focuses on fault escarpments in a general pattern cascade, where ages decrease from the summits of the steep foothills. The ages of 51 sediment samples indicate a correlation with global climate following pulses: Last Interestadial-UI, the Last Glacial Maximum - LGM and the transition Pleistocene / Holocene, while the latter focus on 18 of 51 samples dated. This study also finds evidence of a new quaternary basin, here called Merejo Basin. Through these results it is concluded that no evidence of post-Cretaceous tectonic evolution of morphological MP, as their retreat along the fault scarps, invariably following the trend of the shear zones. The erosion of cliffs in large time scale is controlled by weakness zones generated by faults on the other hand the erosion of cliffs in short time, with the formation of deposits and colluvial horizons pedogenizados, has climate control. It was also found that in the study area there is a preponderance of past and current tectonic erosion processes on the morphological evolution

Análise de uso e cobertura do solo no município de Parelhas/RN

The human interference in the semiarid region of Seridó Potiguar has promoted the increase of degraded areas. The economic dynamic that was established in the Seridó territory, especially after the fall of the trinomial cattle-cotton-mining in the 70s and 80s of the 20th century as pillars of the regional economy, resulted in an accelerated process of erosion of natural resources. The municipalities of the Seridó region have been spatially reordered by this new economic dynamic, marked by the growth of existing enterprises, and the development of new agricultural practices. One of the municipalities in the region that restructured its territorial space with the emergence of new agro-industrial activities was the town of Parelhas. With the demise of the trinomial cattle-cotton-mining in the 1980s, other productive activities were intensified from the 1990s, amongst them, pottery, responsible for the vegetal extraction for use as energy source. This recent economic and spatial restructuring in the region, reflected in the Parelhense municipal territory, required new productive ingredients responsible for the modification of past production relations that were based on cattle, cotton and mining. By that a process of exploring the environment was unleashed, especially the native vegetation, in an uncontrolled manner. In this context, the objective of this study was to survey and detect deforestation in the areas of Caatinga vegetation, used indiscriminately as energy supply for new agricultural practices, using remote sensing techniques based on the quantification of the Normalized Difference Vegetation Index / NDVI, Soil-Adjusted Vegetation Index / SAVI, surface temperature and rainfall data in the years 1990 and 2010. The results indicated that SAVI values above 0.2 in 1990 and 2010 represent the areas with the highest density of vegetation that occur exclusively along the major drainages in the town and areas of higher elevations. The areas between the ranges of values from 0.5 to 0.15 SAVI are areas with poor vegetation. On the other hand the highest values of temperature are distributed in the western and southeastern parts of the township, usually in places where the soil is exposed or there is sparse vegetation. The areas of bare soil decreased in extension in 2010 at 11, 6% when related to 1990, this was caused by a higher rainfall intensity in the first half of 2010, but no regeneration of vegetation occurred in some places in the western and southeastern areas of the municipality today, due to the extraction of firewood to fuel the furnaces of industries in town

Análise hidrodinâmica e morfodinâmica do complexo estuarino do Rio Piranhas-Açu/RN, Nordeste do Brasil

The aim of this study was the seasonal characterization of the morphology, sedimentology and hydrodynamic of the Açu, Cavalos and Conchas estuaries. These estuaries are inserted in a semi-arid climate area and form the mouth of the hydrographic basin of the Piranhas-Açu river, that represent the discharge of the largest watershed in the state. They are embedded in an environment consisting of a fluvial-marine floodplain, mangrove ecosystem, sandbanks, fields of dunes, spits and sandy beaches. Adjacent to the natural units are the main local socioeconomic activities (oil industry, salt industry, shrimp farming, fishing and tourism) are dependent on this river and its conservation. The environmental monitoring is necessary because it is an area under constant action of coastal processes and at high risk of oil spill. The acquisition and interpretation of hydrodynamic, sonographic and sediment data was conducted in two campaigns, dry season (2010) and rainy season (2011), using respectively the current profiler ADCP Doppler effect, the side-scan sonar and Van Veen sampler. In these estuaries: Açu, Cavalos and Conchas were identified the following types of bedforms: flatbed and Dunes 2-D and 3-D (small to medium size), generated at lower flow regime (Froude number <1). Structures such as ripples were observed in the Açu estuary mouth. The higher values of flow discharge and velocity were recorded in the Açu estuary (434,992 m³.s-¹ and 0,554 m.s-¹). In rainy season, despite the record of highest values of discharge and flow velocities at the mouth, the energy rates upstream did not differ much from the data of the dry season. However, in all estuaries were recorded an increase in speed and flow, with reservation to the flow in the Açu estuary and flow at the mouth of the Conchas estuary. Sediment grain sizes tend to increase towards the mouth of the estuary and these ranged from very fine sand to very coarse sand, medium sand fraction being the most recurrent. Based on the data acquired and analyzed, the estuaries Açu, Cavalos and Conchas are classified as mixed , dominated by waves and tides. According to their morphology, they are classified as estuaries constructed by bar and according to the classification by salinity, estuaries Conchas and Cavalos were ranked as hypersaline estuaries, and Açu as hypersaline and vertically well mixed type C

Detecção de áreas degradadas na sub-bacia hidrográfica do rio taperoá/pb, utilizando parâmetros físicos dos sensores modis/terra e tm/landsat

This study includes the results of the analysis of areas susceptible to degradation by remote sensing in semi-arid region, which is a matter of concern and affects the whole population and the catalyst of this process occurs by the deforestation of the savanna and improper practices by the use of soil. The objective of this research is to use biophysical parameters of the MODIS / Terra and images TM/Landsat-5 to determine areas susceptible to degradation in semi-arid Paraiba. The study area is located in the central interior of Paraíba, in the sub-basin of the River Taperoá, with average annual rainfall below 400 mm and average annual temperature of 28 ° C. To draw up the map of vegetation were used TM/Landsat-5 images, specifically, the composition 5R4G3B colored, commonly used for mapping land use. This map was produced by unsupervised classification by maximum likelihood. The legend corresponds to the following targets: savanna vegetation sparse and dense, riparian vegetation and exposed soil. The biophysical parameters used in the MODIS were emissivity, albedo and vegetation index for NDVI (NDVI). The GIS computer programs used were Modis Reprojections Tools and System Information Processing Georeferenced (SPRING), which was set up and worked the bank of information from sensors MODIS and TM and ArcGIS software for making maps more customizable. Initially, we evaluated the behavior of the vegetation emissivity by adapting equation Bastiaanssen on NDVI for spatialize emissivity and observe changes during the year 2006. The albedo was used to view your percentage of increase in the periods December 2003 and 2004. The image sensor of Landsat TM were used for the month of December 2005, according to the availability of images and in periods of low emissivity. For these applications were made in language programs for GIS Algebraic Space (LEGAL), which is a routine programming SPRING, which allows you to perform various types of algebras of spatial data and maps. For the detection of areas susceptible to environmental degradation took into account the behavior of the emissivity of the savanna that showed seasonal coinciding with the rainy season, reaching a maximum emissivity in the months April to July and in the remaining months of a low emissivity . With the images of the albedo of December 2003 and 2004, it was verified the percentage increase, which allowed the generation of two distinct classes: areas with increased variation percentage of 1 to 11.6% and the percentage change in areas with less than 1 % albedo. It was then possible to generate the map of susceptibility to environmental degradation, with the intersection of the class of exposed soil with varying percentage of the albedo, resulting in classes susceptibility to environmental degradation

Fragilidade ambiental da bacia hidrográfica do Rio Seridó (RN/PB Brasil)

There are many applications coming from geomorphological studies and their different constitutive and inter related elements, to the implementation of public politics of planning and environmental management. This search presents an analysis of the environmental fragility of the watershed of Seridó River, situated between the states of Paraíba and Rio Grande do Norte (Brazil), including the identification of possible unstable areas. It is based on the methodological approach of Ecodynamics of the French researcher J. Tricart (1977) and on the operalisation proposal advocated by the Brazilian J. Ross (1994), related to the Potential and Emerging Ecodynamic Units, grounded in the Relief s Dissection Index or the topographic roughness, soil, rainfall and land use/vegetal cover. Under a quantitative perspective, the results obtained from the analysis of the watershed can be divided into classes of potential fragility: around 2.613,0 km² of low intensity, 5.188,4 km² of medium intensity and 2.585,5 km² of high intensity. Concerning the emerging fragility, the results are close to 2.212,0 km² of low intensity, 6.191,23 km² of medium intensity and 2.062,34 km² of high intensity. In the case of the watershed in question, the environmental degradation is particularly effective in the areas more dissected, where the ecological conditions, in synergy the environmental degradation, prevent the regeneration of vegetation when arises an opportunity for the (re)establishment of its equilibrium tenuous. The collected data is relevant for the territorial and environmental planning of the watershed, once we can still verify a close association of the cities on the central area of desertification with the areas of high environmental instability/fragility. This is an important tool to the understanding of the potential susceptibility of the natural and anthropic environments related to the advance and/or intensification of the erosion process, rock falls, mass movements, among other phenomena inside the potential unstable areas. From this perspective, the continuity of this research becomes extremely important to the understanding and arrangement of the process, together with the engendering and sustainability of the system in its totality; in narrow correlation because their potentialities, constraints and alternatives on Seridó River watershed, and in all the semi-arid region with similar characteristics

Morfologia de nectários em Leguminosae senso lato em áreas de caatinga no Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Physiological diversity in tolerance to water deprivation among species of South American desert rodents

Rodents from and and semi-arid deserts are faced with the problem of water conservation. The physiological responses of small rodents to such conditions have been intensively investigated over broad geographically disjunct areas. Despite the presence of xeric habitats in South America since the late Tertiary, some studies suggest that sigmodontine South-American desert rodents do not display the same diversity of physiological responses at the species level as those observed in other desert-dwelling species of rodents. In this paper, we analyzed the physiological responses to water deprivation, at the interespecific and interindividual level, among eight species of sigmodontine desert-dwelling rodents from different geographical areas within South-American deserts. Using randomization tests, we found no significant phylogenetic signal for resistance to water deprivation or for individual variability in this response. Contrary to our initial predictions, we observed that sigmodontine rodents from arid/semi-arid habitats (Monte Desert) had significantly lower rates of body mass loss per day (higher tolerances to water deprivation) than species from the hyperarid deserts. We showed that sigmodontine rodents from South America showed a remarkable diversity of physiological mechanisms for coping with water shortage resulting from different evolutionary adaptive strategies. This diversity, however, displays a rather unexpected pattern in terms of its geographical distribution. (c) 2007 Elsevier Ltd. All rights reserved.

Morfometria e acúmulo de biomassa em palma forrageira sob doses de nitrogênio

Objetivou-se avaliar parâmetros morfológicos e de produção em Palma forrageira cv. Miúda, sob doses de adubo nitrogenado. Além disso, apontar características morfológicas que possam ser utilizadas como variáveis preditoras da massa fresca dos cladódios. O experimento foi conduzido num delineamento inteiramente casualizado, com quatro tratamentos (ausência de adubação nitrogenada, 100; 200 e 300kg/ha de nitrogênio) e quatro repetições. Não houve diferenças significativas (P>0,10) para as características morfogênicas e comprimento dos cladódios. A adubação nitrogenada exerceu efeito linear negativo para as características largura, espessura, volume e peso médio de cladódios e efeito linear positivo para número de cladódios. Houve correlação linear positiva entre a massa fresca e as características morfológicas dos cladódios. O uso da adubação nitrogenada não interfere nas características morfogênicas e na produção de biomassa da palma forrageira. O volume dos cladódios pode ser usado como variável preditora para a massa fresca dos cladódios.

Divergência genética entre acessos de Passiflora cincinnata mast com base em descritores morfoagronômicos

Este trabalho teve como finalidade estimar a divergência genética entre acessos de maracujazeiro (Passiflora cincinnata Mast.) conservados na coleção de trabalho da Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Semi-Árido, em Petrolina-PE. O experimento foi conduzido em delineamento de blocos ao acaso, com quatro repetições. A avaliação foi realizada em 32 acessos, com base em 23 caracteres: dois relativos à planta, três às folhas, seis às flores, quatro aos frutos, quatro às sementes, dois às características químicas dos frutos e dois à produção. O comportamento dos acessos foi pesquisado pelas análises univariada e multivariada, com estimativas das dissimilaridades obtidas pela distância generalizada de Mahalanobis (D²) e formação do agrupamento pelo método de Tocher. Os acessos apresentaram variabilidade genética para todos os descritores utilizados na avaliação. As distâncias genéticas entre pares de acessos variaram de 17 a 598, com média 152. O acesso 18-D0542 foi indicado como o mais divergente e o mais produtivo, devendo compor programas de intercruzamentos e ser recomendado para cultivos experimentais por produtores. As características de maior importância para a divergência genética foram: a massa total dos frutos (42,29%), a viabilidade de pólen (8,62%) e a área foliar (7,16%). O agrupamento dos acessos não se correlaciona às Unidades Geoambientais originais de coleta.

Ocorrência de Zaprionus indianus gupta (Diptera: Drosophilidae) em frutos de juazeiro Ziziphus joazeiro mart. (rhamnaceae) no estado do Rio Grande do Norte

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Inibidores de síntese de giberelinas e crescimento de mudas de mangueira 'Tommy Atkins'

A mangicultura no semiárido brasileiro destaca-se pelos altos rendimentos, pela qualidade do fruto produzido e pela possibilidade de produção durante todo o ano, devido a condições climáticas e tecnologias para o manejo do crescimento vegetativo e da floração, com uso da irrigação, podas e retardantes vegetais. O paclobutrazol aplicado ao solo é utilizado no manejo da produção da mangueira na maioria dos pomares. Entretanto, há a necessidade de identificar retardantes vegetais que possam ser aplicados via foliar, de forma a minimizar os resíduos no solo e evitar o uso de quantidades inadequadas ao longo dos anos. Assim, este trabalho teve como objetivo avaliar retardantes vegetais aplicados via foliar na inibição do crescimento vegetativo de mudas de mangueira 'Tommy Atkins'. Prohexadione-Ca, etil-trinexapac e cloreto de chlormequat, aplicados via foliar, na dose de 1g i.a. planta-1, regulam o crescimento de ramos vegetativos, mas apresentam tempo diferenciado de atividade nas mudas, sendo 20 dias para prohexadione-Ca, 30 dias para cloreto de chlormequat e 45 dias para etil-trinexapac, nas condições em que o experimento foi conduzido.

Substratos para produção de mudas de mamoneira compostos por misturas de cinco fontes de matéria orgânica

O plantio de mamona (Ricinus communis L.) através de mudas pode ser uma alternativa para um melhor aproveitamento da curta estação chuvosa do semi-árido brasileiro, porém ainda não se dispõe de informações básicas para o emprego desta técnica. Na formulação de substratos para produção de mudas de mamona, as características físicas, principalmente a aeração, são fatores de grande importância. O presente estudo objetivou avaliar a composição de substratos utilizando misturas de solo, esterco bovino, casca de amendoim, mucilagem de sisal, bagaço de cana e cama de frango. Utilizou-se delineamento em blocos casualizados com 12 tratamentos e quatro repetições. Sementes da cultivar BRS Nordestina foram semeadas em sacos plásticos de 17 x 28cm, contendo misturas dos materiais a serem testados. Valores de altura, área foliar, número de folhas e diâmetro caulinar foram registrados semanalmente entre 15 e 43 dias após a emergência. Na última coleta também se registraram a massa seca da parte aérea e das raízes. O substrato composto por solo + casca de amendoim + cama de frango + mucilagem de sisal propiciou o melhor crescimento das mudas. A cama de frango contribuiu para o enriquecimento químico do substrato, enquanto a casca de amendoim e a mucilagem de sisal contribuíram para adequar as características físicas de aeração e retenção de água.

Volume de recipientes e composição de substratos para produção de mudas de mamoneira

A mamoneira (Ricinus communis L.)é uma oleaginosa bem adaptada ao cultivo na região semi-árida por sua rusticidade e resistência ao estresse hídrico. Seu plantio é tradicionalmente feito por sementes, mas o uso de mudas pode se tornar atraente como estratégia para melhor aproveitamento da curta estação chuvosa. Para adoção desta tecnologia, a definição de aspectos técnicos como volume de recipientes, composição do substrato e período de permanência da muda no viveiro são fundamentais para o êxito da técnica. Conduziu-se experimento em casa-de-vegetação da Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Algodão em Campina Grande, com sementes da cultivar de mamona de porte médio BRS Nordestina, em delineamento de blocos casualizados com 4 repetições e 25 tratamentos em distribuição fatorial 5², sendo os fatores cinco volumes de recipientes e cinco composições de substratos. Entre 15 e 43 dias após a emergência (DAE) foram feitas cinco coletas destrutivas semanais para obtenção de dados de altura, diâmetro caulinar, área foliar, número de folhas e matéria seca da parte aérea e radicular. Com os dados obtidos calculou-se o tamanho da folha. Detectaram-se efeitos significativos dos tratamentos em todas as variáveis estudadas. O crescimento das mudas estabilizou-se aproximadamente aos 36 DAE, independente do volume do recipiente. Os substratos compostos por mistura de areia com esterco bovino ou casca de amendoim propiciaram o melhor crescimento das mudas, enquanto aqueles contendo bagaço de cana ou mucilagem de sisal foram os piores. Recipientes de 2 L de volume foram os mais adequados para a produção de mudas de mamoneira.

Acidez total titulável, pH e tempo de redução do azul de metileno no fluido ruminal de caprinos mantidos em pastagens artificiais, exclusiva de gramíneas, ou em caatinga

O objetivo deste trabalho foi o de determinar a concentração hidrogeniônica (pH), acidez total titulável e tempo de redução do azul de metileno no fluido ruminal de caprinos com ou sem raça definida, mantidos em pastagens artificiais, exclusivas de gramíneas, ou em caatinga, durante as épocas chuvosa e seca do ano. O delineamento experimental foi inteiramente casualizado, sendo analisado em esquema fatorial 2³ (animais com e sem raça definida, pastagens artificiais e em caatinga, épocas chuvosa e seca do ano). O tipo de pastagem influenciou significativamente (p < 0,05) os valores encontrados para acidez total titulável. em relação ao pH, o tipo de pastagem e época do ano foram significativamente (p < 0,05) os fatores mais incisivos. A atividade microbiana, avaliada através dos parâmetros estudados, foi mais intensa na época das águas e na caatinga em relação à da seca e pastagens artificiais, respectivamente. Na avaliação dos resultados desses testes, deve-se sempre levar em consideração principalmente a época do ano e o tipo de pastagem, sem, no entanto, desprezar o fator raça.

Placentation in the rock cavy, Kerodon rupestris (Wied)

Rock cavies are rodents found in the semi-arid caatinga of Brazil. We studied the structure of the rock cavy placenta by light and transmission electron microscopy. The exchange area of the labyrinth was organized in lobes separated by interlobular areas. The interhaemal barrier was syncytial haemomonochorial. The syncytiotrophoblast had recesses in the basal membrane and some invaginations of the apical membrane, but transtrophoblastic channels could not be found. The interlobular regions comprised syncytiotrophoblast, enclosing maternal venous blood channels, and cytotrophoblast. There was a prominent subplacenta composed of cytotrophoblast and syncytiotrophoblast. Microvilli projected into spaces between the cytotrophoblasts and into lacunae within the syncytiotrophoblast. The yolk sac epithelium exhibited coated pits, endocytotic vesicles and larger vacuoles, consistent with a role in protein uptake from the uterine lumen. Tight junctions between these cells provided a barrier to diffusion by the intercellular route. The reproductive biology of the rock cavy differs from other members of the family, including the guinea pig, but the architecture of the placenta remains remarkably constant. (c) 2004 Elsevier Ltd. All rights reserved.