Relationship between immunoglobulin levels and extremes of solar activity

The possible relationship between epidemics and extremes of solar activity has been discussed previously. The purpose of the present study was to verify whether differences in the levels of immunoglobulins (IgA, IgG, IgM) could be noted at the highest (July 1989) and lowest (September 1986) points of the last (21st) and present (22nd) 11-year solar cycle. The work was divided into a 1-month study (covering the month of minimal or maximal solar activity), a 3-month study (1 month before and after the month of minimal or maximal solar activity) and a 5-month study (2 months before and after the month of minimal or maximal solar activity). A trend of a drop-off for all three immunoglobulins was seen on the far side of the maximal point of the solar cycle. Statistical significance was achieved in the 5-month study for IgM (P=0.04), and a strong trend was shown for IgG (P=0.07). Differences between the sexes were also noted.     

Solar radiation incident on the Martian surface

Summary Calculations indicate that the maximum daily solar radiation reaching the Martian surface is about 325 cal/cm² during southern hemisphere summer at latitude of about 40°S. In the ultraviolet region of the spectrum, the radiation reaching the surface at wavelengths greater than 2800 Å is within 10% of the radiation incident on the atmosphere. There is significant extinction of radiation in the spectral region near 2500 Å in mid and high latitudes due to absorption of radiation by ozone; radiation reaching the surface may be reduced to one one-thousandth of that incident on the atmosphere during winter. Virtually no radiation of wavelengths less than 1900 Å reaches the surface because of absorption by the large column abundance of carbon dioxide. Daily and latitudinal distributions of radiation are presented for wavelengths of 3000, 2500 and 2000 Å.     

Interdiffusion of PCBM and P3HT Reveals Miscibility in a Photovoltaically Active Blend

Developing a better understanding of the evolution of morphology in plastic solar cells is the key to designing new materials and structures that achieve photoconversion efficiencies greater than 10%. In the most extensively characterized system, the poly(3‐hexyl thiophene) (P3HT):[6,6]‐phenyl‐C₆₁‐butyric‐acid‐methyl‐ester (PCBM) bulk heterojunction, the origins and evolution of the blend morphology during processes such as thermal annealing are not well understood. In this work, we use a model system, a bilayer of P3HT and PCBM, to develop a more complete understanding of the miscibility and diffusion of PCBM within P3HT during thermal annealing. We find that PCBM aggregates and/or molecular species are miscible and mobile in disordered P3HT, without disrupting the ordered lamellar stacking of P3HT chains. The fast diffusion of PCBM into the amorphous regions of P3HT suggests the favorability of mixing in this system, opposing the belief that phase‐pure domains form in BHJs due to immiscibility of these two components.     

设施菜田不同碳氮管理对反硝化菌结构和功能的影响

【目的】通过6年长期定位试验,比较设施菜田不同碳氮管理下反硝化菌结构和功能的差异。【方法】采用末端限制性片段多态性(T-RFLP)和变性梯度凝胶电泳(DGGE)方法分别分析nir K/nir S和nos Z型反硝化菌群结构特征,利用自动连续在线培养监测体系(Robot系统)测定分析NO/(NO3-+NO2-)和N2O/(N2O+N2)产物比,并通过乙炔抑制法测定反硝化酶活性。【结果】传统施肥处理(CN)显著改变了nir K和nos Z型反硝化菌的结构,增加了NO/(NO3-+NO2-)和N2O/(N2O+N2)产物比。nir S型菌受碳氮管理影响较小。减氮(RN)和添加秸秆处理(RN+S)的nir K和nos Z型反硝化菌结构与CN处理的差异性显著,且会显著降低NO/(NO3-+NO2-)和N2O/(N2O+N2)产物比;与CN和RN相比,RN+S显著增加反硝化酶活性。【结论】设施菜田长期传统施肥措施改变了反硝化菌的结构和功能,增加土壤自身的NO产生能力并减弱了N2O还原N2的能力。减氮和添加秸秆管理能形成自身的反硝化菌群结构,并降低NO和N2O排放风险;秸秆的添加会促进反硝化潜在速率,降低菜田NO3-淋洗风险。     

Development of species diversity in some mediterranean plant communities

Summary Plant communities in the Mediterranean region have been analyzed with the emphasis on community processes regulating diversity trends. We want to know how several mechanisms that contribute to the maintenance or to the modification of species diversity, act: (i) in different communities, during an ecological succession (from old fields to forests), and (ii) in forest communities throughout the year. Some of these mechanisms were investigated through difference in stratification, life-form, phenology, dispersal agent, and microenvironmental gradient.The paper censists of two parts. The first one deals with the relationship between structural and biological diversity in conjunction with succession stages leading to a Quereus pubescens forest. It is concluded that diversity, however it is measured, fluctuates during the succession: it increases initially (15 years after abandonment) and also in later stages when trees appear in the fields; it decreases after 20 years when Brachypodium phoenicoides dominates and in the latest stages of the succession studied. These trends may be interpreted in relation to the evolution of life form and dispersal agents spectra during the succession.The second part concerns community-structure and biological diversity in relation to the organization of two Quercus pubescens forests. It appears that the species richness in the understory of the forests, may be explained by: (i) the tendency of the modal height of species foliage distribution to oceupy different positions, (ii) the quasicomplete asynchronism in the major phenophases of the dominant species, (iii) different horizontal patterns of species distribution along a light gradient.These schemes are discussed in relation to ecological hypotheses on diversity in relation to succession, and to community organization.Nomenelature follows: P. Fournier (1961). Les quatre flores de France for the Gramineae and Liliaceae, Flora Europea for the other taxa.The support of the Délégation de la Recherche Scientifique et Technique through the grants N567, N633, N674 (Structure et dynamique des formations à Chène pubescent en zone bioclimatique méditerranéenne) is acknowledged. We thank J. Biondel, R. Bonhomme and M. Dueray for technical and scientific assistance. We are greatly indebted to Dr. E. van der Maarel for his helpful improvements of this text.     

The heterotrophic eubacterial and archaeal co-inhabitants of the halophilic Dunaliella salina in solar salterns fed by Bay of Bengal along south eastern coast of India

Halophilic microbes are studied to understand the metabolic pathways adopted by organisms in such extreme environment and for their biotechnological exploitation. In thallosohaline environments worldwide, the autotrophic alga Dunaliella salina Teodoresco is omnipresent, but it is being recently realised that the heterotrophic components vary in different regions. The unexplored eastern coastline of India abutted by Bay of Bengal was investigated for the heterotrophic halophilic microbes in this region. The waters in the salterns – replicas of natural hyper-saline water bodies of that region, were collected at four sites along 650 km of the coastal belt. In cultures set up from these waters, green and pink colonies were observed. The green colonies were found to be those of D. salina while the pink colonies were of heterotrophs. To identify the heterotrophic microbes, light microscopy, 16S rRNA typing and pigment profiling through spectrophotometry and HPLC were done. The cells in pink colonies were rod shaped. 16S rRNA typing of cells in these colonies detected the presence of Halomonas sp. – a eubacterium. The pigment profile of cells in pink cultures matched that of the archaea – Halobacterium; bacterioruberin derivatives were found. Thus, it was concluded that Halomonas and Halobacterium spp. are among the co-inhabitant heterotrophs of D. salina. Cultures of D. salina established from these salterns showed the typical three colours seen in the ponds of different sub-plots of salterns. They were green until 30 days, turning dark orange by 60 days and pink when 90 day old. In the 90 day old cultures, innumerable rod shaped cells were found. These cells were similar to the cells of the waters from the ponds of pink sub-plots of salterns and the pink colonies established from saltern waters in the laboratory. In the old (90 days) laboratory cultures of D. salina, the glycerol and proteins released from degenerating cells and the increase in salt concentration to super saturation levels due to evaporation of water in the medium led to the gregarious appearance of the heterotrophs – the co-inhabitants in natural environment.     

Characterization of halophiles isolated from solar salterns in Baja California, Mexico

Solar salterns are extreme hypersaline environments that are five to ten times saltier than seawater (150–300 g L⁻¹ salt concentration) and typically contain high numbers of halophiles adapted to tolerate such extreme hypersalinity. Thirty-five halophile cultures of both Bacteria and Archaea were isolated from the Exportadora de Sal saltworks in Guerrero Negro, Baja California, Mexico. 16S rRNA sequence analysis showed that these cultured isolates included members belonging to the Halorubrum, Haloarcula, Halomonas, Halovibrio, Salicola, and Salinibacter genera and what may represent a new archaeal genus. For the first time, metabolic substrate usage of halophile isolates was evaluated using the non-colorimetric BIOLOG Phenotype MicroArray™ plates. Unique carbon substrate usage profiles were observed, even for closely related Halorubrum species, with bacterial isolates using more substrates than archaeal cultures. Characterization of these isolates also included morphology and pigmentation analyses, as well as salinity tolerance over a range of 50–300 g L⁻¹ salt concentration. Salinity optima varied between 50 and 250 g L⁻¹ and doubling times varied between 1 and 12 h. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

地理信息系统与模型集成技术在林地林木产量和光能利用率估测中的应用

利用福建省气象要素观测及山地土壤调查资料,探讨地理信息系统和数学模型集成技术在区域林地栅格空间林木产量和光能利用率估测中的应用.结果表明,区域年均温、降水量和太阳总辐射能与经度、纬度及海拔的2次趋势面分析模型相关性均达极显著水平,复相关系数为0.692～0.981.采用地理信息系统与2次趋势面分析及1、2和4次反距离权重插值模型集成技术可分别较准确推算区域太阳总辐射能、年均温和降水量的空间数据,验证气象站点相应气象要素观测值与模型推算值之间的差异均未达显著水平,t值仅分别为1.29、0.12和0.06.借助地理信息系统与相关模型集成技术可实现区域林地栅格空间林木产量和光能利用率的估测,研究区林地林木产量和光能利用率分别为2.32～18.61 m³·hm^-2·yr^-1和0.11%～0.91%.     

Modelling the Persistence of Quiescent Conidia of the Entomopathogenic Hyphomycete Paecilomyces fumosoroseus Exposed to Solar Radiation

Persistence of conidia of the entomopathogenic fungus Paecilomyces fumosoroseus exposed to artificial and solar radiation at a constant temperature was studied by monitoring the ability to germinate and to form colonies (colony - forming units , CFUs) . The photic effect of radiation on each of these variables was modelled by a decreasing function of UVB irradiation ( in J m 2) . Germination ability was represented by a logistic function and viability (log CFU) by an infinitely decreasing function . Experiments carried out under artificial conditions , at three different UVB irradiances ( from 0 . 3 to 1 . 6 W m 2) , similar to those observed in nature , confirmed the adequacy of the predictor variable and of the functions chosen for describing these data . The proposed models appeared to be irradiance independent . Under solar radiation , the models were able to describe data collected on three different summer days in France (48 o 51 N , 2 o 06 E) . However , it took a greater amount of solar UVB radiation to produce the same effect as that achieved indoors . This could be explained by differences in radiation spectra . For each model , one set of parameters was sufficient for representing all three sets of data: this constitutes an initial validation of the models proposed .