银鲫不同雌核发育系的生物学特性比较研究

银鲫不同雌核发育系间,以D系银鲫体型最高,其相对体高平均为47％,A系为44.4％,C系为43.7％,B系为41.7％。在生长速度方面以D系生长最快,其次为A系,这两个系的银鲫在含肉量与肌肉蛋白质含量上均无明显差异,但D系银鲫对饵料的利用效率明显高于A系,因此生产上养殖以D系银鲫为母本,红鲤为父本人工繁殖而成的高体型异育银鲫,可提高经济效益10—20％。银鲫4个雌核发育系的卵巢发育进程不同,D系卵母细胞在2月份有个迅速发育期,因而最早进入成熟产卵期。A系成熟产卵期略晚,C系成熟产卵期较迟。银鲫染色体数目存

Effect of water temperature on the growth performance and digestive enzyme activities of Chinese longsnout catfish (Leiocassis longirostris Gunther)

The present study was carried out to investigate the influence of water temperature on the growth performance and digestive enzyme (pepsin, trypsin and lipase) activities of Chinese longsnout catfish. Triplicate groups of Chinese longsnout catfish (35.6 +/- 0.48 g, mean +/- SE) were reared at different water temperatures (20, 24, 28 and 32 degrees C). The feeding rate (FR), specific growth rate (SGR) and feed efficiency ratio (FER) were significantly affected by water temperatures and regression relationships between water temperature and FI, SGR as well as FER were expressed as FR=-0.016T2+0.91T-10.88 (n=12, R2=0.8752), SGR=-0.026T2+1.39T-17.29 (n=12, R2=0.7599) and FER=-0.013T2+0.70T-8.43 (n=12, R2=0.7272). Based on these, the optimum temperatures for FR, SGR and FER were 27.66, 26.69 and 26.44 degrees C respectively. The specific activities of digestive enzymes at 24 or 28 degrees C were significantly higher than that at 20 or 32 degrees C. In addition, there was a significant linear regression between FR or SGR and specific activities of pepsin and lipase, which indicated that pepsin and lipase played important roles in regulating growth through nutrient digestion in Chinese longsnout catfish.

溶胶-凝胶法制备ZnO纳米薄膜的工艺和应用

ZnO是一种重要的功能材料和新型的n一Ⅵ族宽禁带半导体材料。采用溶胶一凝胶(sol-gel)工艺在si(100)、si(111)和c面蓝宝石衬底上成功制备出高质量的ZnO纳米薄膜，并用XRD、SEM、AFM等方法研究了薄膜的特性。首次以制备的ZnO纳米薄膜为缓冲层，在n型si(1()o)衬底上采用低压化学气相沉积(LPCVD)工艺外延生长了SiC薄膜，得到了低载流子浓度、高电子迁移率和高空穴迁移率的两种SiC薄膜样品，分析了该薄膜的性能。

杉木与阔叶树叶凋落物混合分解对土壤活性有机质的影响

通过室内培养,研究了杉木叶凋落物及与桤木、刺楸和火力楠混合叶凋落物对土壤活性有机质的影响.结果表明:添加叶凋落物显著地增加了土壤微生物碳、氮及土壤呼吸强度和可溶性有机碳含量.其中,添加杉-阔混合叶凋落物对土壤活性有机质的增加效应大于纯杉木叶凋落物.在培养后期(第135天),添加纯杉木叶凋落物和杉-阔混合叶凋落物处理土壤微生物碳含量分别比对照土壤高49%和63%,微生物氮高35%和75%,土壤呼吸强度高65%和100%,可溶性有机碳含量高66%和108%.添加叶凋落物对土壤微生物熵和微生物C/N的影响不显著(P>0·05).

Crystal form transition during heating of solvent-induced crystalline syndiotactic polystyrene

The phase transition of two kinds of solvent-induced crystalline syndiotactic polystyrene (sPS). gamma-sPS and delta(c)-sPS, has been studied via WAXD and DSC. gamma-sPS transform to a-sPS at 195-225 degrees C before melt during heating, whereas delta(e)-sPS transform to first gamma-sPS and then a-sPS at 100-200 degrees C and 200-215 degrees C, respectively. The transition of delta(e)-gamma and gamma-a occurs for below melting point of sPS indicates they are all solid-solid transition.

Influence of interface on radiation effects of crystalline polymer - radiation effects on polyamide-1010 containing BMI

Aimed at saving the radiation dose required to crosslinking the polyamid-1010, BMI/PA1010 systems containing different amounts of difunctional crosslinking agent N,N'-bis-maleimide-4,4'-biphenyl methane (BMI) were prepared and the structure changes at the crystallographic and supermolecular levels before and after irradiation were studied by using WAXD, SAXS, and DSC techniques. It was found that by incorporation of BMI the microcrystal size L-100 is lowered due to the formation of hydrogen bond between the carbonyl oxygen of BMI and the amide hydrogen of PA1010 in the hydrogen bonded plane, and the overall crystallinity W-c is also decreased. The presence of BMI causes the crystal lamella thickness d(c) to decrease and greatly thickens the transition zone d(tr) between the crystalline and amorphous regions. As for the irradiated specimen, the maximum increments in the L-100 and W-c against dose curves decrease with BMI content, and the interception point D-i, at which the L-100 and W-c curves intercept their respective horizontal line of L-100/L-100(0) and W-c/W-c(0)=1, shift to lower dose with an increase in BMI concentration. In addition. the mechanism of the radiation chemical reactions in the three different phases under the action of BMI are discussed with special focus on the interface region. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.

Geotecnologias como ferramentas de apoio à certificação da qualidade no campo: noções gerais

Apresentamos de forma breve os marcos conceituais do desenvolvimento sustentável e da avaliação integrada da sustentabilidade. Consideramos, que estes são, por um lado, um importante pilar filosófico, duramente construído nas ultimas décadas e, por outro, um importante instrumento de apoio à gestão ambiental em distintos âmbitos geográficos. Principalmente quando a sustentabilidade é medida através de indicadores de desempenho, que devem obrigatoriamente representar a realidade das complexas interações ambientais no espaço e no tempo. Partimos da lógica de que para o desenvolvimento sustentável de uma região, localidade ou propriedade, devemos necessariamente considerar as interações de seus três componentes fundamentais e indissociáveis, quais sejam: seu perfil social, seu perfil econômico e seu perfil ecológico. Tal consideração, associada à percepção e análise em múltipla escala, reafirmam, cada vez mais, sua importância como instrumento de gestão dos recursos naturais e das atividades humanas desenvolvidas em uma determinada região, sempre considerando sua inserção espacial e temporal, permitindo entre outras coisas, apontar os conflitos a serem analisados e as soluções locais a serem implementadas. Dentro de um contexto mais localizado, a meta final é auxiliar a gestão ambiental de propriedades rurais através de critérios científicos, com resultados quantificáveis, atendendo as normas atuais e se preparando para as futuras exigências da certificação da produção e da qualidade de produtos agrícolas, impostas pelo mercado. Abordamos também importantes temas e aplicações do vasto campo de conhecimento relacionado ao geoprocessamento, ou, como vem sendo denominado mais recentemente, às geotecnologias. O principal enfoque é reforçar sua importância como instrumento de avaliação e prognóstico em distintas escalas ou âmbitos geográficos, bem como a integração de suas principais ferramentas metodológicas, possibilitando a organização dos dados e informações em aplicações dirigidas à gestão ambiental da propriedade rural e de seu entorno. Finalmente, são feitas considerações das aplicações mais relevantes da geotecnologia como ferramenta de apoio à conformidade das exigências do Protocolo Europeu de Boas Práticas Agrícolas.

Folha índice para avaliação do estado nutricional do pinhão-manso

2014

Novel DNA sensor for guanine content.

The bifunctional complex [Ru(TAP)(2)POQ-Nmet](2+), 1, formed with a [Ru(TAP)(2)Phen](2+) metallic unit linked to a quinoline moiety, and [Ru(TAP)(2)Phen](2+), 2, as reference, have been tested as photoprobes of DNA. Interestingly, 1 exhibits an emission enhancement of a factor of 16-17 upon binding to calf thymus DNA. Moreover, this emission is modulated by the nucleic base content of the polynucleotide. It varies by almost an order of magnitude from a polynucleotide containing 100% of G-C to a guanine-free nucleic acid where the excited-state lifetime reaches about 2 micros. The origins of these interesting properties are analyzed by comparing 1 with reference 2 in the presence of different polynucleotides.

Validación de un modelo de balance hidrológico versátil para maíz en condiciones de semiáridez

p.125-132

Plankton Of The Fladen Ground During Flex-76 .3. Vertical-Distribution Population-Dynamics And Production Of Calanus-Finmarchicus (Crustacea Copepoda)

Samples taken in the northern North Sea with the Continuous Plankton Recorder (CPR), the Undulating Oceanographic Recorder (UOR), the Longhurst Hardy Plankton Recorder (LHPR) and by our colleagues from other participating Institutes during the Fladen Ground Experiment (FLEX 76) were used to describe the vertical distribution and population dynamics of Calanus finmarchicus (Gunnerus) and to provide estimates of the production and carbon budget of the population from 19 March to 3 June, 1976. Total production of the 19 March to 3 June, 1976. Total production of the nauplii and copepodite stages (including adults), during the exponential growth phase in May, was estimated to be in the range of 0.49 to 0.91 g C m-2 d-1 or 29.0 to 55 g dry wt m-2 (14.5 to 27.8 g C m-2) for the three successive 10 d periods in May. Two gross growth efficiencies (K 1) (20 and 34%), together with the lower value of C. finmarchicus production, were used to calculate the gross ingestion levels of algae as 2.45 and 1.44 g C m-2 d-1 (73.5 and 43.2 g C m-2 over the May period). These ingestion levels, together with the algae ingested by other zooplankton species, are greater than the estimated total phytoplankton production of 45.9 g C m-2 over the FLEX period. A number of factors are discussed which could explain the discrepancies between the production estimates. One suggestion is that the vertical distribution of the development stages of this herbivorous copepod and their diel and ontogenetic migration patterns enable it to efficiently exploit its food source. Data from the FLEX experiment indicated that the depletion of nutrients limited the size of the spring bloom, but that it was the grazing pressure exerted by C. finmarchicus which was responsible for the control and depletion of the phytoplankton in the spring of 1976 in the northern North Sea.

Space-based lidar measurements of global ocean carbon stocks

Global ocean phytoplankton biomass (C-phyto) and total particulate organic carbon (POC) stocks have largely been characterized from space using passive ocean color measurements. A space-based light detection and ranging (lidar) system can provide valuable complementary observations for C-phyto and POC assessments, with benefits including day-night sampling, observations through absorbing aerosols and thin cloud layers, and capabilities for vertical profiling through the water column. Here we use measurements from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) to quantify global C-phyto and POC from retrievals of subsurface particulate backscatter coefficients (b(bp)). CALIOP b(bp) data compare favorably with airborne, ship-based, and passive ocean data and yield global average mixed-layer standing stocks of 0.44 Pg C for C-phyto and 1.9 Pg for POC. CALIOP-based C-phyto and POC data exhibit global distributions and seasonal variations consistent with ocean plankton ecology. Our findings support the use of spaceborne lidar measurements for advancing understanding of global plankton systems.

Scanning electron microscopy study of microstructural evolution of electroless nickel-phosphorus deposits with heat treatment

This paper follows previous X-ray diffraction work on crystallisation and phase transformation of electroless nickel–phosphorus deposits, concentrating on microstructural changes. Amorphous or nanocrystalline coatings, depending on their phosphorus content, were heat treated at temperatures between 100 and 500 °C for 1 h. Changes in microstructure after the heat treatment were examined using high-resolution field emission scanning electron microscope. Crystallisation and grain growth effects are observed, as well as some inherent defect structures in the coatings and their changes. These are compared with the previous X-ray diffraction work and in general, good agreement is observed. The complementary strength and weakness of the different characterisation techniques are discussed.

Molecular testing of respiratory swabs aids early recognition of meningococcal disease in children

Early meningococcal disease (MD) diagnosis is difficult. We assessed rapid molecular testing of respiratory specimens. We performed genotyping of respiratory swabs, blood, and cerebrospinal fluid from children with suspected disease and nasal swabs (NSs) from matched controls. Thirty-nine of 104 suspected cases had confirmed disease. Four controls were carriers. Throat swab ctrA and porA testing for detection of disease gave a sensitivity of 81% (17/21), specificity of 100% (44/44), positive predictive value (PPV) of 100% (17/17), negative predictive value (NPV) of 92% (44/48), and relative risk of 12. NS ctrA and porA testing gave a sensitivity of 51% (20/39), specificity of 95% (62/65), PPV of 87% (20/23), NPV of 77% (62/81), and relative risk of 4. Including only the 86 NSs taken within 48 h of presentation, the results were sensitivity of 60% (18/30), specificity of 96% (54/56), PPV of 90% (18/20), NPV of 82% (54/66), and relative risk of 5. Swab type agreement was excellent (kappa 0.80, P

Burkholderia cenocepacia requires RpoE for growth under stress conditions and delay of phagolysosomal fusion in macrophages

Burkholderia cenocepacia is an opportunistic pathogen causing serious infections in patients with cystic fibrosis. The widespread distribution of this bacterium in the environment suggests that it must adapt to stress to be able to survive. We identified in B. cenocepacia K56-2 a gene predicted to encode RpoE, the extra-cytoplasmic stress response regulator. The rpoE gene is the first gene of a predicted operon encoding proteins homologous to RseA, RseB, MucD and a protein of unknown function. The genomic organization and the co-transcription of these genes were confirmed by PCR and RT-PCR. The mucD and rpoE genes were mutated, giving rise to B. cenocepacia RSF24 and RSF25, respectively. While mutant RSF24 did not demonstrate any growth defects under the conditions tested, RSF25 was compromised for growth under temperature (44 degrees C) and osmotic stress (426 mM NaCl). Expression of RpoE in trans could complement the osmotic growth defect but exacerbated temperature sensitivity in both RSF25 and wild-type K56-2. Inactivation of rpoE altered the bacterial cell surface, as indicated by increased binding of the fluorescent dye calcofluor white and by an altered outer-membrane protein profile. These cell surface changes were restored by complementation with a plasmid encoding rpoE. Macrophage infections in which bacterial colocalization with fluorescent dextran was examined demonstrated that the rpoE mutant could not delay the fusion of B. cenocepacia-containing vacuoles with lysosomes, in contrast to the parental strain K56-2. These data show that B. cenocepacia rpoE is required for bacterial growth under certain stress conditions and for the ability of intracellular bacteria to delay phagolysosomal fusion in macrophages.