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We describe and compare the histology of liver and spleen ofGeophagus brasiliensis (Perciformes), Hypostomus francisci (Siluriformes) and Hoplias aff. malabaricus (Characiformes), tropical freshwater fishes. InG. brasiliensisandH. aff. malabaricusthe hepatocytes were arranged in tubular form whereas in H. franciscithey cord-like. In all species, hepatocytes presented glycogen, but in G. brasiliensis and H. aff. malabaricus they showed strong stained for hemossiderin in the cytoplasm. InG. brasiliensis and H. aff. malabaricus, melanomacrophage centres (MMCs) were associated to hepatic structures and only in G. brasiliensis was observed intrahepatic exocrine pancreas. The spleen, in all species, was characterized by red and white pulp without boundary between the two regions, but only in H. francisci was recorded nodular organization in splenic parenchyma. The G. brasiliensisandH. aff. malabaricuspresented in the white pulp MMCs linked mainly to ellipsoids. Besides, we observed large MMCs in the spleen in relation to liver of G. brasiliensis and H. aff. malabaricus. In liver, highest values of reticular fibers and collagen were observed inG. brasiliensis. In spleen, highest values of reticular fibers and collagen were recorded inH. aff. malabaricusandH. francisci, respectively. Histological differences confirm the hypothesis that the phylogenetic distance is reflected in liver and spleen. RESUMO Nós descrevemos e comparamos a histologia do fígado e do baço de Geophagus brasiliensis (Perciformes), Hypostomus francisci (Siluriformes) e Hoplias aff. malabaricus (Characiformes), peixes neotropicais de água doce. Em G. brasiliensis e H. aff. malabaricus os hepatócitos organizaram-se na forma tubular enquanto que em H. francisci eles apresentaram-se como cordões celulares. Em todas as espécies, os hepatócitos apresentaram glicogênio, mas em G. brasiliensis e H. aff. malabaricus, eles mostraram forte marcação para hemossiderina no citoplasma. Em G. brasiliensis e H. aff. malabaricus, centros melanomacrofágicos (CMMs) foram associados a estruturas hepáticas e somente em G. brasiliensis foi observado pâncreas exócrino intrahepático. O baço, em todas as espécies, foi caracterizado pela polpa vermelha e branca sem limites entre as duas regiões, mas somente em H. francisci foi registrado uma organização nodular no parênquima esplênico. G. brasiliensiseH. aff. malabaricusapresentaram na polpa branca CMMs associados principalmente a elipsoides. Além disso, nós observamos CMMs grandes no baço em relação ao fígado de G. brasiliensis e de H. aff. malabaricus. No fígado, valores altos de fibras reticulares e colágeno foram observado em G. brasiliensis. No baço, valores altos de fibras reticulares e colágeno foram registrados em H. aff. malabaricuseH. francisci, respectivamente. Diferenças histológicas confirmam a hipótese que a distância filogenética está refletida no fígado e no baço.

Located at the transition between the Saharian and Sahelian zones, at the center of one of the largest endoreic basins, the Lake Chad is ideally located to record regional environmental changes that occurred in the past. However, until now, no continuous archive from Lake Chad covering the Holocene has been studied. In this paper, we present pollen data from the first Holocene sedimentary sequence collected in Lake Chad (13° N; 14° E; Sahel region). Dated between ca. 6700 and ca. 5000 cal yr BP, this record encompasses the termination of the African Humid Period (AHP). Vegetational reconstructions are based on standard analyses of the pollen diagrams and are strengthened by quantitative approaches. Potential biomes that occurred at that time around Mega-Lake Chad are reconstructed using the biomization method and mean annual precipitation is estimated using the modern analogues technique. Results show that between ca. 6700 and ca. 6050 cal yr BP, a vegetation close to humid woodland or humid savanna, including elements currently found much further southward, thrived in the vicinity and/or the extra-local environment of the Mega-Lake Chad in place of the modern steppe, dry woodland and desert vegetation observed today. At the same time, montane forest populations extended further southward on the Adamawa plateau. This vegetation distribution is supported by biome reconstructions as well as by mean annual precipitation estimates of ca. 800 (−400/+700) mm for the period. The high abundance of lowland humid pollen taxa is interpreted as the result of a northward migration of the corresponding plants during the AHP driven by more favorable climatic conditions. Our interpretation in favor of a regional vegetation response to climatic changes is supported by other pollen data from several Northwestern African records. However, we cannot rule out that an increase of Chari-Logone inputs into the Mega-Lake Chad due to variations in hydrological regime might have contributed to the higher abundance of lowland humid pollen taxa observed in the mid-Holocene sedimentary sequence. Changes in the structure and floristic composition of the vegetation towards more open and drier formations occurred after ca. 6050 cal yr BP. This is also evidenced by a decrease in mean annual precipitation estimates to approximately 600 (−230/+600) mm. This change corresponds to the onset of the AHP termination. The constant presence of lowland humid taxa until ca. 5000 cal yr BP, even if displaying a slight decrease, contemporaneous with an increase in steppic taxa, demonstrates that at ca. 5000 cal yr BP the modern vegetation was not yet established in the vicinity of Lake Chad. Our data indicate that vegetational change during this period must have occurred progressively, at least over 1000 yr, and are inconsistent with an abrupt aridification and a collapse of the vegetation cover in the East-Central Saharan and Sahelian regions at the AHP termination.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:51:49Z No. of bitstreams: 1 S0100-83582008000200023.pdf: 1206343 bytes, checksum: 0187dc9c6f068033d4bcfed913d8a6ce (MD5) Made available in DSpace on 2013-08-22T18:51:49Z (GMT). No. of bitstreams: 1 S0100-83582008000200023.pdf: 1206343 bytes, checksum: 0187dc9c6f068033d4bcfed913d8a6ce (MD5) Previous issue date: 2008-06-01 Made available in DSpace on 2013-09-30T19:42:51Z (GMT). No. of bitstreams: 2 S0100-83582008000200023.pdf: 1206343 bytes, checksum: 0187dc9c6f068033d4bcfed913d8a6ce (MD5) S0100-83582008000200023.pdf.txt: 26107 bytes, checksum: c64cc227ffccb0f0edb4a81cc12bea89 (MD5) Previous issue date: 2008-06-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:19:52Z No. of bitstreams: 2 S0100-83582008000200023.pdf: 1206343 bytes, checksum: 0187dc9c6f068033d4bcfed913d8a6ce (MD5) S0100-83582008000200023.pdf.txt: 26107 bytes, checksum: c64cc227ffccb0f0edb4a81cc12bea89 (MD5) Made available in DSpace on 2014-05-20T13:19:52Z (GMT). No. of bitstreams: 2 S0100-83582008000200023.pdf: 1206343 bytes, checksum: 0187dc9c6f068033d4bcfed913d8a6ce (MD5) S0100-83582008000200023.pdf.txt: 26107 bytes, checksum: c64cc227ffccb0f0edb4a81cc12bea89 (MD5) Previous issue date: 2008-06-01 Com o objetivo de avaliar os efeitos da aplicação em jato dirigido com e sem proteção do bico de pulverização através de chapéu-de-napoleão para misturas de herbicidas de ação total na cultura da mamoneira de porte anão, na safra 2004/2005, um experimento foi conduzido no município de Garça-SP, utilizando-se o híbrido Lyra e espaçamento de 1,0 x 0,5 m. O delineamento experimental utilizado foi o de blocos casualizados, com tratamentos em esquema fatorial 2 x 10, com quatro repetições, em que o primeiro fator representou a forma de aplicação de jato dirigido com e sem uso de chapéu-de-napoleão e o segundo os herbicidas: glyphosate (0,72 kg ha-1); glyphosate + 2,4-D (0,72 + 0,35 kg ha-1); glyphosate + flumioxazin (0,72 + 0,025 kg ha-1); glyphosate + carfentrazone-ethyl (0,72 + 0,016 kg ha-1); glyphosate + diuron (0,72 + 0,75 kg ha-1); MSMA + diuron (1,44+ 0,75 kg ha-1); paraquat + diuron (0,9 kg ha-1); paraquat + diquat (0,20 + 0,20 kg ha-1); paraquat + bentazon (0,40 + 0,48 kg ha-1); e testemunha capinada. A aplicação dos herbicidas foi feita em pós-emergência das plantas daninhas, nas entrelinhas da cultura, utilizando-se pulverizador costal pressurizado com CO2, com uma ponta XR 8002-VS para o uso de chapéu-de-napoleão e duas pontas XR 11002-VS, espaçadas de 50 cm, para condição sem proteção, ambas com consumo de calda equivalente a 200 L ha-1. O herbicida glyphosate e as misturas de paraquat + bentazon, glyphosate + 2,4-D e paraquat + diquat proporcionaram os maiores níveis de produtividade da mamoneira Lyra quando aplicados em jato dirigido e com auxílio de chapéu-de-napoleão. As misturas paraquat + bentazon (0,40 + 0,48 kg ha-1) e paraquat + diquat (0,20 + 0,20 kg ha-1) demonstraram ser as mais indicadas para aplicação em jato dirigido com proteção do bico de pulverização. An experiment was carried out in Garca-SP to evaluate the effects of application using a direct sprayer with and without Napoleons's hat protection for total action herbicide tank mixtures on dwarf internode castor bean crop during the 2004/2005 agricultural year, with Lyra hybrid in a 1.0 x 0.5 m spacing. The experimental design was randomized complete blocks, with treatments in a factorial scheme 2 x 10, with four replications, the first factor being direct sprayer application with and without Napoleon's hat protection and the second application of the herbicides glyphosate (0.72 kg ha-1); glyphosate + 2,4-D (0.72 + 0.35 kg ha¹); glyphosate + flumioxazin (0.72 + 0.025 kg ha-1); glyphosate + carfentrazone-ethyl (0.72 + 0.016 kg ha-1); glyphosate + diuron (0.72 + 0.75 kg ha-1); MSMA + diuron (1.44+ 0.75 kg ha-1); paraquat + diuron (0.9 kg ha-1); paraquat + diquat (0.20 + 0.20 kg ha-1); paraquat + bentazon (0.40 + 0.48 kg ha-1) and hand weeded check. Herbicide application was accomplished in weed post-emergence, between crop lines,using a carbon dioxide-pressurized backpack sprayer, with one XR 8002-VS nozzle for Napoleon's hat protection and two XR 11002-VS nozzles,50 cm spaced , without protection, both using 200 L ha-1 of water. Glyphosate and paraquat + bentazon, glyphosate + 2,4-D and paraquat + diquat tank mixtures provided the highest yield levels for Lyra castor bean hybrid, when applied using a direct sprayer with Napoleon's hat protection. Paraquat + bentazon (0..4 + 0.48 kg ha-1) and paraquat + diquat (0.20 + 0.20 kg ha-1) tank mixtures were the most indicated for direct sprayer with nozzle protection. Escola Superior de Agronomia de Paraguaçu Paulista Universidade Estadual Paulista Faculdade de Ciências Agronômicas SAA Coordenadoria de Assistência Técnica Integral Centro de Testes, Avaliação e Divulgação Faculdade de Agronomia e Engenharia Florestal de Garça ESAPP Universidade Estadual Paulista Faculdade de Ciências Agronômicas