Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 260 )

2018 ( 520 )

2017 ( 517 )

2016 ( 717 )

Custom range...

Search Results: 1 - 10 of 418437 matches for " Pablo J. F. Pena Rodrigues "
All listed articles are free for downloading (OA Articles)
Page 1 /418437
Display every page Item
Does Linear Canopy Openings in a Lowland Atlantic Tropical Forest Cause Edge Effects on Seedling Communities?  [PDF]
Pablo J. F. Pena Rodrigues, Mariana A. Iguatemy, Marcelo T. Nascimento
Open Journal of Ecology (OJE) , 2014, DOI: 10.4236/oje.2014.415078
Abstract: Edge effects and linear canopy openings may change ecological patterns and processes on forests. Here we investigate if these openings in a lowland Brazilian Atlantic forest cause edge effects on seedlings. We sampled seedling communities at forest edges near to two linear canopy openings (gas pipeline and power line) and in interiors far from edges. Comparisons between the seedling communities were performed to access edge effects. Density and basal area patterns were compared using, hierarchical two-way ANOVAs and the number of newly germinated seedlings, mortality and resprouts were compared by one-way ANOVAs. The results showed that edge effects of linear canopy openings affect seedling communities leading to low densities on edges that showed less favorable conditions for arrival, establishment and initial survival. The basal area patterns were not affected by edge effects apparently by the resistance of the seedlings that have more than 4 mm diameter. Therefore, linear canopy openings caused edge effects, which determine low seedling densities on edges. However this pattern is not due to increase mortality on these edges, but probably caused by the reduction on germination and establishment.
Edge Effects of Oil Pipeline Canopy Openings on Tree Community Structure and Dynamics in a Montane Atlantic Forest  [PDF]
Pablo J. F. Pena Rodrigues, Leticia R. Melo, Rodolfo C. R. de Abreu, Mariana A. Iguatemy
Journal of Geoscience and Environment Protection (GEP) , 2016, DOI: 10.4236/gep.2016.47014
Abstract: The Atlantic forest has historically been severely deforested, and only fragments currently remain that are subject to a wide variety of anthropogenic impacts, including edge effects that can cause structural and functional degradation. The Tinguá Biological Reserve-RJ comprises approximately 26,000 hectares of well-preserved Atlantic Forest, but it is subject to impacts caused by two canopy openings along oil pipelines. Comparisons were made between pipeline edges and forest interiors to evaluate edge effects on the structure and dynamics of those tree communities. Tree densities were higher along forest edges, apparently increasing over time. Tree basal areas, on the other hand, have decreased along edges due to higher mortality rates. Linear canopy opening edges showed higher densities of small trees, while the interior had more very large trees, indicating changes in successional processes and community structural patterns due to edge effects.
The effect of water-level fluctuations on swamp forest colonization by seedlings of Tabebuia cassinoides DC. (Bignoniaceae)  [PDF]
Pablo José Francisco Pena Rodrigues, Mariana de Andrade Iguatemy
Open Journal of Ecology (OJE) , 2011, DOI: 10.4236/oje.2011.13008
Abstract: Establishment of Tabebuia cassinoides seedlings is related to water-level fluctuations in southeastern Brazil swamp forests. Nine years of annual monitoring of 48 individuals established during a drought in November 1997, when the swamp was unflooded, suggested that their establishment depends on this unpredictable event. This conclusion is further sustained by the wide variability of the seedling cohort size structure, and the fascicular root conformation that holds the shoots erect.
Urban Cholera Transmission Hotspots and Their Implications for Reactive Vaccination: Evidence from Bissau City, Guinea Bissau
Andrew S. Azman,Francisco J. Luquero,Amabelia Rodrigues,Pedro Pablo Palma,Rebecca F. Grais,Cunhate Na Banga,Bryan T. Grenfell,Justin Lessler
PLOS Neglected Tropical Diseases , 2012, DOI: 10.1371/journal.pntd.0001901
Abstract: Background Use of cholera vaccines in response to epidemics (reactive vaccination) may provide an effective supplement to traditional control measures. In Haiti, reactive vaccination was considered but, until recently, rejected in part due to limited global supply of vaccine. Using Bissau City, Guinea-Bissau as a case study, we explore neighborhood-level transmission dynamics to understand if, with limited vaccine and likely delays, reactive vaccination can significantly change the course of a cholera epidemic. Methods and Findings We fit a spatially explicit meta-population model of cholera transmission within Bissau City to data from 7,551 suspected cholera cases from a 2008 epidemic. We estimated the effect reactive vaccination campaigns would have had on the epidemic under different levels of vaccine coverage and campaign start dates. We compared highly focused and diffuse strategies for distributing vaccine throughout the city. We found wide variation in the efficiency of cholera transmission both within and between areas of the city. “Hotspots”, where transmission was most efficient, appear to drive the epidemic. In particular one area, Bandim, was a necessary driver of the 2008 epidemic in Bissau City. If vaccine supply were limited but could have been distributed within the first 80 days of the epidemic, targeting vaccination at Bandim would have averted the most cases both within this area and throughout the city. Regardless of the distribution strategy used, timely distribution of vaccine in response to an ongoing cholera epidemic can prevent cases and save lives. Conclusions Reactive vaccination can be a useful tool for controlling cholera epidemics, especially in urban areas like Bissau City. Particular neighborhoods may be responsible for driving a city's cholera epidemic; timely and targeted reactive vaccination at such neighborhoods may be the most effective way to prevent cholera cases both within that neighborhood and throughout the city.
Ancestral Genomes, Sex, and the Population Structure of Trypanosoma cruzi
Jorge M. de Freitas equal contributor,Luiz Augusto-Pinto equal contributor,Juliana R Pimenta equal contributor,Luciana Bastos-Rodrigues,Vanessa F Gon?alves,Santuza M. R Teixeira,Egler Chiari,?ngela C. V Junqueira,Octavio Fernandes,Andréa M Macedo,Carlos Renato Machado,Sérgio D. J Pena
PLOS Pathogens , 2006, DOI: 10.1371/journal.ppat.0020024
Abstract: Acquisition of detailed knowledge of the structure and evolution of Trypanosoma cruzi populations is essential for control of Chagas disease. We profiled 75 strains of the parasite with five nuclear microsatellite loci, 24Sα RNA genes, and sequence polymorphisms in the mitochondrial cytochrome oxidase subunit II gene. We also used sequences available in GenBank for the mitochondrial genes cytochrome B and NADH dehydrogenase subunit 1. A multidimensional scaling plot (MDS) based in microsatellite data divided the parasites into four clusters corresponding to T. cruzi I (MDS-cluster A), T. cruzi II (MDS-cluster C), a third group of T. cruzi strains (MDS-cluster B), and hybrid strains (MDS-cluster BH). The first two clusters matched respectively mitochondrial clades A and C, while the other two belonged to mitochondrial clade B. The 24Sα rDNA and microsatellite profiling data were combined into multilocus genotypes that were analyzed by the haplotype reconstruction program PHASE. We identified 141 haplotypes that were clearly distributed into three haplogroups (X, Y, and Z). All strains belonging to T. cruzi I (MDS-cluster A) were Z/Z, the T. cruzi II strains (MDS-cluster C) were Y/Y, and those belonging to MDS-cluster B (unclassified T. cruzi) had X/X haplogroup genotypes. The strains grouped in the MDS-cluster BH were X/Y, confirming their hybrid character. Based on these results we propose the following minimal scenario for T. cruzi evolution. In a distant past there were at a minimum three ancestral lineages that we may call, respectively, T. cruzi I, T. cruzi II, and T. cruzi III. At least two hybridization events involving T. cruzi II and T. cruzi III produced evolutionarily viable progeny. In both events, the mitochondrial recipient (as identified by the mitochondrial clade of the hybrid strains) was T. cruzi II and the mitochondrial donor was T. cruzi III.
Nueva especie de lagarto del género Liolaemus (Reptilia: Liolaemidae) del norte de Chile, previamente confundido con Liolaemus (=Phrynosaura) reichei
Valladares F., J. Pablo
Cuadernos de Herpetología , 2004,
Abstract: Se describe una nueva especie de lagarto para el norte de Chile, la que es asignada al grupo montanus del género Liolaemus. La nueva especie difiere de las especies del subgrupo boulengeri en que carece de un parche de escamas alargadas en la parte femoral de la extremidad posterior. Difiere de las demás especies del grupo montanus en su tama o mediano, algunas escamas dorsales muy suavemente carenadas, casi lisas, redondeadas, suavemente imbricadas. Presenta dimorfismo sexual, se encuentra sobre los 1000 m de altura y su hábitat corresponde a hiperdesierto o desierto interior. We describe a new species of lizards from the north of Chile and are belonging to the montanus group of the Liolaemus genus. The new species differs from the boulengeri group in lacking a patch of enlarged scales on the posterior thigh. It differs from the remaining species of the montanus group by its moderate size, some dorsal scales with slight keels, smooth, and rounded dorsal body scale and mildly imbricate. It has a sexual dimorphims, it occurs over 1000 m of elevation and their habitat corresponds to the hiperdesert or interior desert.
Diagramas de equilibrio cuaternarios ZrO2-Al2O 3-SiO 2- (CaO, MgO, TiO2). Una poderosa herramienta para el desarrollo de nuevos materiales por sinterización reactiva
Moya, J. S.,Batolomé, J. F.,Pena, P.
Boletín de la Sociedad Espa?ola de Cerámica y Vidrio , 2011, DOI: 10.3989/cyv.382011
Abstract: In this paper we set out, discuss and evaluate the work on Mullite-zirconia composites obtained by reaction sintering led and inspired by Salvador de Aza on the basis of ZrO2-Al2O3-SiO2(CaO, MgO, TiO2) multicomponent phase equilibrium diagrams. We analyze their impact on different areas of ceramic science and technology such as refractory grogs, aluminum industry, etc. The possible fields of future applications such as dental prosthesis replacing partially stabilized zirconia materials with rare earths are also reported. En este articulo se exponen, discuten y evalúan los trabajos que sobre materiales de Mullita-Circona obtenidos por sinterización reactiva dirigió e inspiro Salvador de Aza sobre la base de los diagramas de equilibrio de fase multicomponentes ZrO2-Al2O3-SiO2-(CaO, MgO, TiO2). Se analiza su impacto en distintas áreas de la ciencia y tecnología cerámicas tales como chamotas refractarias, industria del aluminio, etc. También se proponen posibles campos de aplicación futura como es el caso de prótesis dentales sustituyendo a los materiales de circona parcialmente estabilizada con tierras raras.
The continuum limit of the quark mass step scaling function in quenched lattice QCD
M. Guagnelli,J. Heitger,F. Palombi,C. Pena,A. Vladikas
Physics , 2004, DOI: 10.1088/1126-6708/2004/05/001
Abstract: The renormalisation group running of the quark mass is determined non-perturbatively for a large range of scales, by computing the step scaling function in the Schroedinger Functional formalism of quenched lattice QCD both with and without O(a) improvement. A one-loop perturbative calculation of the discretisation effects has been carried out for both the Wilson and the Clover-improved actions and for a large number of lattice resolutions. The non-perturbative computation yields continuum results which are regularisation independent, thus providing convincing evidence for the uniqueness of the continuum limit. As a byproduct, the ratio of the renormalisation group invariant quark mass to the quark mass, renormalised at a hadronic scale, is obtained with very high accuracy.
Differential vulnerability of substantia nigra and corpus striatum to oxidative insult induced by reduced dietary levels of essential fatty acids
Henriqueta D. Cardoso,Priscila P. Passos,Claudia J. Lagranha,Anete C. Ferraz,Eraldo F. Santos Júnior,Rafael S. Oliveira,Pablo E. L. Oliveira,Rita de C. F. Santos,David F. Santana,Juliana M. C. Borba,Ana P. Rocha-de-Melo,Rubem C. A. Guedes,Daniela M. A. F. Navarro,Geanne K. N. Santos,Roseane Borner,Cristovam W. Pican?o-Diniz,Eduardo I. Beltr?o,Janilson F. Silva,Marcelo C. A. Rodrigues,Belmira L. S. Andrade da Costa
Frontiers in Human Neuroscience , 2012, DOI: 10.3389/fnhum.2012.00249
Abstract: Oxidative stress (OS) has been implicated in the etiology of certain neurodegenerative disorders. Some of these disorders have been associated with unbalanced levels of essential fatty acids (EFA). The response of certain brain regions to OS, however, is not uniform and a selective vulnerability or resilience can occur. In our previous study on rat brains, we observed that a two-generation EFA dietary restriction reduced the number and size of dopaminergic neurons in the substantia nigra (SN) rostro-dorso-medial. To understand whether OS contributes to this effect, we assessed the status of lipid peroxidation (LP) and anti-oxidant markers in both SN and corpus striatum (CS) of rats submitted to this dietary treatment for one (F1) or two (F2) generations. Wistar rats were raised from conception on control or experimental diets containing adequate or reduced levels of linoleic and α-linolenic fatty acids, respectively. LP was measured using the thiobarbituric acid reaction method (TBARS) and the total superoxide dismutase (t-SOD) and catalase (CAT) enzymatic activities were assessed. The experimental diet significantly reduced the docosahexaenoic acid (DHA) levels of SN phospholipids in the F1 (~28%) and F2 (~50%) groups. In F1 adult animals of the experimental group there was no LP in both SN and CS. Consistently, there was a significant increase in the t-SOD activity (p < 0.01) in both regions. In EF2 young animals, degeneration in dopaminergic and non-dopaminergic neurons and a significant increase in LP (p < 0.01) and decrease in the CAT activity (p < 0.001) were detected in the SN, while no inter-group difference was found for these parameters in the CS. Conversely, a significant increase in t-SOD activity (p < 0.05) was detected in the CS of the experimental group compared to the control. The results show that unbalanced EFA dietary levels reduce the redox balance in the SN and reveal mechanisms of resilience in the CS under this stressful condition.
DNA tests probe the genomic ancestry of Brazilians
Pena, S.D.J.;Bastos-Rodrigues, L.;Pimenta, J.R.;Bydlowski, S.P.;
Brazilian Journal of Medical and Biological Research , 2009, DOI: 10.1590/S0100-879X2009005000026
Abstract: we review studies from our laboratories using different molecular tools to characterize the ancestry of brazilians in reference to their amerindian, european and african roots. initially we used uniparental dna markers to investigate the contribution of distinct y chromosome and mitochondrial dna lineages to present-day populations. high levels of genetic admixture and strong directional mating between european males and amerindian and african females were unraveled. we next analyzed different types of biparental autosomal polymorphisms. especially useful was a set of 40 insertion-deletion polymorphisms (indels) that when studied worldwide proved exquisitely sensitive in discriminating between amerindians, europeans and sub-saharan africans. when applied to the study of brazilians these markers confirmed extensive genomic admixture, but also demonstrated a strong imprint of the massive european immigration wave in the 19th and 20th centuries. the high individual ancestral variability observed suggests that each brazilian has a singular proportion of amerindian, european and african ancestries in his mosaic genome. in brazil, one cannot predict the color of persons from their genomic ancestry nor the opposite. brazilians should be assessed on a personal basis, as 190 million human beings, and not as members of color groups.
Page 1 /418437
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.