METASTABLE DEFECT IN AMORPHOUS-SILICON SOLAR-CELLS INVESTIGATED BY JUNCTION RECOVERY TECHNIQUE

The effect of metastable defects caused by light soaking and carrier injection on the transport of carriers in undoped a-Si:H has been investigated by a junction recovery technique. The experiments show that after light soaking or carrier injection the product of mu-p-tau-p decreases, but no detectable change in the distribution of shallow valence band tail states was found.

沈阳市苔藓植物及其对大气质量的指示作用

沈阳是东北地区重要的老工业基地，也是该地区的交通枢纽。本文在对沈阳市进行广泛调查并采集苔藓植物标本的基础上，系统地研究了沈阳市苔藓植物的种类构成、区系、分布格局及其与环境因子的关系，同时利用苔藓植物对沈阳市的大气质量进行了指示。得出的主要结论有： （1）对882份苔藓植物标本进行鉴定，共记录苔藓植物30科67属143种及变种，其中包括苔类（含角苔）9科11属14种，藓类21科56属128种1变种。在记录中发现辽宁省新记录属1个，新纪录种36种，东北新纪录种18种，主要以丛藓科（Pottiaceae）和真藓科（Bryaceae）等地面生藓类为主。 （2）将研究区苔藓植物划分为10个区系成分，其中以北温带分布占据绝对优势，其次为东亚分布和中国特有分布，具强烈的温带性质。通过相似性系数的计算，表明沈阳市苔藓植物区系与鞍山市和抚顺市的亲缘性较大；与上海市和杭州市亲缘性较远。 （3）应用TWINSPAN和DCA，以样点为对象，苔藓植物的重要值为指标，对研究区苔藓植物分布格局进行了分析。结果将样点划分为三个组，从组一到组三，物种丰富度和苔藓盖度逐渐增加。分类与排序的结果与样点的实际物种分布特点基本一致。 （4）采用CCA对沈阳市35种主要地面苔藓植物与环境因子间的关系进行了分析。根据环境因子的影响，将沈阳市主要地面苔藓植物分为两类。同时发现土壤含水量、乔木层郁闭度和人为干扰是影响沈阳市苔藓植物分布的主要因素。 （5）采用大气净度指数法（IAP）和重金属元素（Mn, Fe, Cu, Cr和Pb）化学分析法对沈阳市的大气质量进行了监测。结果表明市区污染远重于郊区，市区西部污染重于东部，南部重于北部；各区以Pb污染最为严重，值得重视。同空气污染指数（API）进行比较，发现IAP与Cu、Pb和API之间具显著负相关性，说明随着重金属含量和API值的升高，IAP值降低，即苔藓植物的种类和盖度下降。以IAP值为自变量，API值为因变量，建立了回归方程y=-0.914x+101.849，进一步说明了IAP值与API值之间的关系。

Efficient red organic light-emitting diode sensitized by phosphorescent Ir compound

The efficiencies of red organic light-emitting diode (OLED) using tris-(8-hydroxy-quinoline)aluminum (Alq(3)) as host and 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) as dopant were greatly increased by adding a small amount (0.3 wt%) of Ir compound, iridium(III) bis(3-(2-benzothiazolyl)-7-(diethylamino)-2H-1-benzopyran-2-onato-N-',C-4) (acetyl acetonate) (Ir(C6)(2)(acac)), as a sensitizer

Bond-charge calculation of electro-optic coefficients of diatomic crystals

A theoretical method has been set up to calculate the electrooptic tensor coefficients r(ijk), based on the Phillips-Van Vechten (PV) dielectric theory and the Levine bond charge model, Starting from the crystal structure data and only introducing the experimentally determined optical permittivity and dielectric constant, the electro-optic tensor coefficients r(ijk) can be quantitatively predicted, The theoretical calculations are in good agreement with experiment in the case of zinc blende and wurtzite crystals, For zinc blende crystals, the effects of covalent radii on the linear electro-optic coefficients are discussed. (C) 1997 Academic Press.

Process control in agile supply chain network.

The work comprises a new theoretical development applied to aid decision making in an increasingly important commercial sector. Agile supply, where small volumes of high margin, short life cycle innovative products are offered, is increasingly carried out through a complex global supply chain network. We outline an equilibrium solution in such a supply chain network, which works through limited cooperation and coordination along edges (links) in the network. The links constitute the stochastic modelling entities rather than the nodes of the network. We utilise newly developed phase plane analysis to identify, model and predict characteristic behaviour in supply chain networks. The phase plane charts profile the flow of inventory and identify out of control conditions. They maintain quality within the network, as well as intelligently track the way the network evolves in conditions of changing variability. The methodology is essentially distribution free, relying as it does on the study of forecasting errors, and can be used to examine contractual details as well as strategic and game theoretical concepts between decision-making components (agents) of a network. We illustrate with typical data drawn from supply chain agile fashion products.

Two-stage open shop scheduling with a bottleneck machine

It is known that for the open shop scheduling problem to minimize the makespan there exists no polynomial-time heuristic algorithm that guarantees a worst-case performance ratio better than 5/4, unless P6≠NP. However, this result holds only if the instance of the problem contains jobs consisting of at least three operations. This paper considers the open shop scheduling problem, provided that each job consists of at most two operations, one of which is to be processed on one of the m⩾2 machines, while the other operation must be performed on the bottleneck machine, the same for all jobs. For this NP-hard problem we present a heuristic algorithm and show that its worst-case performance ratio is 5/4.

Ecological effects of the North Atlantic oscillation

Climatic oscillations as reflected in atmospheric modes such as the North Atlantic Oscillation (NAO) may be seen as a proxy for regulating forces in aquatic and terrestrial ecosystems. Our review highlights the variety of climate processes related to the NAO and the diversity in the type of ecological responses that different biological groups can display. Available evidence suggests that the NAO influences ecological dynamics in both marine and terrestrial systems, and its effects may be seen in variation at the individual, population and community levels. The ecological responses to the NAO encompass changes in timing of reproduction, population dynamics, abundance, spatial distribution and interspecific relationships such as competition and predator-prey relationships. This indicates that local responses to large-scale changes may be more subtle than previously suggested. We propose that the NAO effects may be classified as three types: direct, indirect and integrated. Such a classification will help the design and interpretation of analyses attempting to relate ecological changes to the NAO and, possibly, to climate in general.

Long-term variability of the siphonophores Muggiaea atlantica and M. kochi in the Western English Channel

We investigated long-term variability of the calycophoran siphonophores Muggiaea atlantica and Muggiaea kochi in the Western English Channel (WEC) between 1930 and 2011. Our aims were to describe long-term changes in abundance and temporal distribution in relation to local environmental dynamics. In order to better understand mechanisms that regulate the species’ populations, we identified periods that were characteristic of in situ population growth and the environmental optima associated with these events. Our results show that between 1930 and the 1960s both M. atlantica and M. kochi were transient components of the WEC ecosystem. In the late 1960s M. atlantica, successfully established a resident population in the WEC, while the occurrence of M. kochi became increasingly sporadic. Once established as a resident species, the seasonal abundance and distribution of M. atlantica increased. Analysis of environmental conditions associated with in situ population growth revealed that temperature and prey were key determinants of the seasonal distribution and abundance of M. atlantica. Salinity was shown to have an indirect effect, likely representing a proxy for water circulation in the WEC. Anomalies in the seasonal cycle of salinity, indicating deviation from the usual circulation pattern in the WEC, were negatively associated with in situ growth, suggesting dispersal of the locally developing M. atlantica population. However, our findings identified complexity in the relationship between characteristics of the environment and M. atlantica variability. The transition from a period of transiency (1930–1968) to residency (1969–2011) was tentatively attributed to structural changes in the WEC ecosystem that occurred under the forcing of wider-scale hydroclimatic changes.

The occurrence and significance of triploidy in the liver fluke, Fasciola hepatica.

Karyotyping of Fasciola hepatica samples from Britain and Ireland has identified a triploid isolate which is effectively aspermic, rendering it necessarily asexually reproducing. Considering the extensive presence of asexually reproducing diploid and triploid Fasciola in Asia it is suggested that facultative gynogenesis is widespread in this parasite. This has important implications for the population genetics and evolution of Fasciola, especially in relation to the development and spread of drug resistance, and must be considered in the mathematical modelling of this process.

The structural organization of aurein precursor cDNAs from the skin secretion of the Australian green and golden bell frog, Litoria aurea.

Aureins are a family of peptides (13-25 residues), some of which possess potent antimicrobial and anti-cancer properties, which have been classified into 5 subgroups based upon primary structural similarities. They were originally isolated from the defensive skin secretions of the closely related Australian bell frogs, Litoria aurea and Litoria raniformis, and of the 23 aurein peptides identified, 10 are common to both species. Using a recently developed technique, we have constructed a cDNA library from the defensive secretion of the green and golden bell frog, L. aurea, and successfully cloned a range of aurein precursor transcripts containing entire open-reading frames. All open-reading frames consisted of a putative signal peptide and an acidic pro-region followed by a single copy of aurein. The deduced precursor structures for the most active aureins (2.2 and 3.1) confirmed the presence of a C-terminal amidation motif whereas that of aurein 5.3 did not. Processed peptides corresponding in molecular mass to aureins 2.2, 2.3, 2.5, 3.1 and 5.3 were identified in the same secretion sample using LC/MS. The application of this technique thus permits parallel peptidomic and transcriptomic analyses on the same lyophilized skin secretion sample circumventing sacrifice of specimens of endangered herpetofauna.

Activities of an aqueous plant extract against Herpes simplex virus type 2 (HSV 2): role in virus replication and progeny yield

Tese de mestrado, Biologia Molecular e Genética, Universidade de Lisboa, Faculdade de Ciências, 2015

Breve historia del alma, o el alma en la historia

Si afirmamos una “Historia del Alma”, partimos de una mínima intuición, y es que ésta no sólo existe, sino que podemos pretender hacerle un seguimiento, o por lo menos ubicarla como entidad presente en un espacio y tiempo determinados