Chert intervals in DSDP and ODP sites (Table 1)

Radiolarian cherts in the Tethyan realm of Jurassic age were recently interpreted as resulting from high biosiliceous productivity along upwelling zones in subequatorial paleolatitudes the locations of which were confirmed by revised paleomagnetic estimates. However, the widespread occurrence of cherts in the Eocene suggests that cherts may not always be reliable proxies of latitude and upwelling zones. In a new survey of the global spatio-temporal distribution of Cenozoic cherts in Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) sediment cores, we found that cherts occur most frequently in the Paleocene and early Eocene, with a peak in occurrences at ~50 Ma that is coincident with the time of highest bottom water temperatures of the early Eocene climatic optimum (EECO) when the global ocean was presumably characterized by reduced upwelling efficiency and biosiliceous productivity. Cherts occur less commonly during the subsequent Eocene global cooling trend. Primary paleoclimatic factors rather than secondary diagenetic processes seem therefore to control chert formation. This timing of peak Eocene chert occurrence, which is supported by detailed stratigraphic correlations, contradicts currently accepted models that involve an initial loading of large amounts of dissolved silica from enhanced weathering and/or volcanism in a supposedly sluggish ocean of the EECO, followed during the subsequent middle Eocene global cooling by more vigorous oceanic circulation and consequent upwelling that made this silica reservoir available for enhanced biosilicification, with the formation of chert as a result of biosilica transformation during diagenesis. Instead, we suggest that basin-basin fractionation by deep-sea circulation could have raised the concentration of EECO dissolved silica especially in the North Atlantic, where an alternative mode of silica burial involving widespread direct precipitation and/or absorption of silica by clay minerals could have been operative in order to maintain balance between silica input and output during the upwelling-deficient conditions of the EECO. Cherts may therefore not always be proxies of biosiliceous productivity associated with latitudinally focused upwelling zones.

Palynofacies analysis of sediments in the eastern Equatorial Atlantic

Analyses of the palynofacies and sporomorph thermal alteration indices (TAI) of sediments from Ocean Drilling Program (ODP) Sites 959 to 962 in the Cote d'Ivoire-Ghana Transform Margin, West Africa were undertaken to (1) determine the source and depositional conditions of the organic matter in the sediments, (2) refine a paleobathymetric curve derived from other data for Site 959, which drilled the most continuous sedimentary sequence from Pleistocene to Albian and (3) interpret the paleothermal history of the area. Twelve types of dispersed organic matter were identified: amorphous organic matter (AOM), marine palynomorphs, algae, resins, black debris, yellow-brown fragments, black-brown fragments, cuticles, plant tissue, wood, sporomorphs and fungi, The relative abundances of these organic matter components at each site were analyzed using cluster analysis, resulting in the identification of seven palynofacies assemblages at Site 959, five each at sites 960 and 961, and four at Site 962. Amorphous organic matter (which is chiefly marine derived), black debris and wood have played the most significant role in defining palynofacies assemblages. The palynofacies assemblages show some correlation with lithologic units, sediment sources and depositional environments. Previous palynofacies studies in passive margins have demonstrated that changes in the ratio of AOM to terrestrial organic matter are related primarily to proximal-distal positions of depositional environments relative to the shoreline. However, this assumption does not always hold true for a transform margin where tectonic factors play an important role in the organic matter distribution, at least in the early stages of evolution. Lithofacies, CCD paleodepths for the North Atlantic, trace fossil association, benthic foraminifera and palynofacies data were the criteria used for reconstructing a paleobathymetric curve for Site 959. A cyclicity in the organic matter distribution of the Upper Miocene to Lower Pliocene pelagic sediments could be related to fluctuations in productivity of biosiliceous and calcareous organisms, and sedimentation rates. A drastic increase in the amount of AOM and a decrease in black debris and wood in the carbonate and clastic rocks (Lithologic Unit IV) overlying the tectonized Albian sediments (Lithologic Unit V) at Sites 959 and 960 coincide with the presence of an unconformity. Qualitative color analysis of palynomorphs was undertaken for all sites, although the main focus was on Site 959 where detailed organic geochemical data were available. At Site 959, TAI values indicate an immature stage of organic maturation (<2) down to the black claystones of Lithologic Unit III at about 918.47 mbsf. Below this, samples show an increase with depth to a moderately mature stage (>2 except for the claystone samples between 1012.52 and 1036.5 mbsf, and one limestone sample at 1043.4 mbsf), reaching peak levels of 2.58 to 3.0 in the tectonized Albian sediments below the unconformity. These TAI values show a positive correlation with the Tma x values derived from Rock-Eval pyrolysis data. The highest values recorded in the basal tectonized units at all the sites (Sites 960-962 have mean values between 2.25 and 3.13) may be related to high heat flow during the intracontinental to syntransform basin stage in the region.

Diário da Constituinte [gravação de vídeo] : [programa n. 159]

Está pronto o calendário das sessões extraordinárias para o debate dos temas polêmicos da Assembleia Nacional Constituinte. O Deputado Bocayuva Cunha (PDT-RJ) espera a participação popular e que a sociedade possa acompanhar a posição dos partidos e dos constituintes em relação aos temas a serem debatidos. O PT quer discutir mais os temas sociais. O Deputado Vladimir Palmeiras (PT-RJ) declara que a bancada terá uma intervenção mais sistemática no Plenário, no sentido de afirmar que a redução da jornada de trabalho e a estabilidade no emprego são pontos essenciais para discussão do texto constitucional. Reunião do Grupo Interpartidário, com representantes do PMDB, PT, PDT, PCB e PFL, buscam o consenso. O Deputado Antonio Brito (PMDB-RS) afirma que a sabedoria de uma Constituinte é tentar estabelecer o que o país tem em comum, para criar uma Constituição duradoura. Na reunião interpartidária, os constituintes debateram os artigos do anteprojeto que tratam da censura, da criação de um conselho de comunicação social e da reforma agrária e definiram dezenove pontos em torno dos quais buscarão uma posição de consenso nas votações em Plenário. O Deputado Roberto Freire (PCB-PE) destaca a importância do diálogo entre os partidos. O Deputado Mário Covas (PMDB-SP) declara que há uma preocupação comum que é a de ter uma Constituição que reflita os anseios da sociedade brasileira. O Deputado Plínio Arruda Sampaio (PT-SP) afirma que há uma intenção dos grupos progressistas de comporem uma grande aliança para que esta Constituição represente um avanço. O Deputado Alceni Guerra (PFL-PR) defende que a Constituição deve representar o que pensa a sociedade brasileira e deve também ser flexível, para que tanto um governo de esquerda como um de direita possa governar o país. O Deputado Antonio Brito (PMDB-RS) ressalta que, pela primeira vez, os partidos estão negociando e que é isto o que deve ser uma Constituinte. Dom Luciano Mendes, Presidente da Confederação Nacional dos Bispos do Brasil (CNBB), entrega três emendas populares ao Presidente da Assembleia Nacional Constituinte (ANC) Ulysses Guimarães . Dom Luciano ressalta a importância das emendas populares.

The transport of aquatic animals by birds. [Translation from: Binnengewaesser 18, 156-159, 1950.]

A great deal has been written on the part which birds play in the dispersal of freshwater fauna. This article summarises literature on the dispersal of aquatic animals by birds and aquatic insects.

大蹼铃蟾皮肤白蛋白的胰蛋白酶抑制活性研究

通过离子交换层析和凝胶过滤层析,在大蹼铃蟾(Bombina maxima)皮肤中得到其白蛋白.该蛋白有强烈抑制胰蛋白酶水解小肽底物的活性,但对其它丝氨酸蛋白酶如凝血酶、糜蛋白酶、弹性蛋白酶及枯草杆菌蛋白酶无抑制.它以1∶1摩尔比同胰蛋白酶形成稳定结合的复合物.经测定发现,该蛋白对温度、pH值及还原剂二硫苏糖醇的耐受性较强,三种因素对其胰蛋白酶抑制活性影响不大.说明大蹼铃蟾皮肤白蛋白具有稳定的胰蛋白酶抑制活性,可能在大蹼铃蟾防御天敌捕食的过程中发挥重要作用.

中能区~(40)Ar + ~(197)Au/~(159)Tb/~(nat)Ag反应中高激发热核性质研究

通过对中能区Ar+Au/Tb/Ag反应中高激发核的发射时标、发射次序、发射机制、核温度、集体运动等衰变特性的研究，提取了轻粒子和中等质量碎片（IMF）的发射时间，IMF发射时间随束流能的升高而变短，发射机制逐渐由相继衰变过渡至多重碎裂。研究了轻粒子和碎片间的发射次序，对高能粒子和碎片，轻粒子先于碎片发射，而低能时，则为碎片先于轻粒子发射。IMF发射成分与角度和碰撞参数有关，前角区来自于弹核碎裂，后角区来自于类靶热核的蒸发。在平面和出平面研究表明，中速粒子和碎片为在平面发射占主导，即存在类转动效应；对轻粒子，转动效应随粒子质量增加而增加；对中速产物均观测到该效应随碰撞参数饿增大而增大。采用几种不同的方法提取了热核的核温度，研究了不同方法之间的区别。

辽细辛提取物对灰葡萄孢菌的抑制效果

采用生长速率法和孢子萌发法测定了辽细辛根的不同溶剂(石油醚、氯仿、乙酸乙酯、乙醇)粗提取物和精油对引起黄瓜灰霉病的灰葡萄孢菌菌丝生长和孢子萌发的作用。结果表明,细辛不同溶剂提取物和精油对灰葡萄孢菌的菌丝生长和孢子萌发均有一定的抑制作用,且对孢子萌发的抑制效果好于对其菌丝生长的抑制效果;石油醚提取物和精油的抑菌效果较好,对菌丝生长的EC50分别为177.44 mg/L和159.98 mg/L,对孢子萌发的EC50分别为173.23 mg/L和125.29 mg/L;试验还显示细辛所含的主要抑菌活性成分易被极性小的有机溶剂所提取。

The effect of Rh particle size on the catalytic performance of porous silica supported rhodium catalysts for CO hydrogenation

Silica-supported Rh catalysts with different Rh particle dimensions were investigated for CO hydrogenation. The catalysts were characterized by various techniques such as TEM, H-2-TPR and N-2 adsorption to study the catalyst morphology, the size distributions of Rh particles and the silica pores. It was found that the distribution and the size of Rh particles were affected by the silica pores, and the metal grains were enclosed in the pores of the support, and thereby their growth was limited. The catalytic activity and selectivity to C-2-oxygenates for CO hydrogenation were found to be significantly controlled by the Rh particle sizes, and the higher activity and selectivity to C2-oxygenates were obtained over bigger Rh particles, within the range of the reported particle sizes.

Ecological tools for the management of cyanobacteria blooms in the Guadiana River watershed, Southwest Iberia

Strong water demand for irrigation, energy and drinking water production is responsible for an increasingly regulation of freshwater flow patterns and watersheds. In this context, the construction of dams allows water storage but seriously restricts freshwater flow downstream. Due to scarcity of freshwater resources, reservoir water management often promotes high hydraulic residence. This may cause strong impacts on biological components of aquatic ecosystems, influencing the development of cyanobacteria blooms and aggravating their harmful impacts.