12 resultados para Silver question.

em Helda - Digital Repository of University of Helsinki


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The aim of this thesis was to increase our knowledge about the effects of seed origin on the timing of height growth cessation and field performance of silver birch from different latitudes, with special attention paid to the browsing damage by moose in young birch plantations. The effect of seed origin latitude and sowing time on timing of height growth cessation of first-year seedlings was studied in a greenhouse experiment with seven seed origins (lat. 58º - 67ºN). Variation in critical night length (CNL) for 50 % bud set within two latitudinally distant stands (60º and 67ºN) was studied in three phytotron experiments. Browsing by moose on 5-11 -year-old silver birch saplings from latitudinally different seed origins (53º - 67ºN) was studied in a field experiment in southern Finland. Yield and stem quality of 22-year-old silver birch trees of Baltic, Finnish and Russian origin (54º - 63ºN) and the effect of latitudinal seed transfers were studied in two provenance trials at Tuusula, southern and Viitasaari, central Finland. The timing of height growth cessation depended systematically on latitude of seed origin and sowing date. The more northern the seed origin, the earlier the growth cessation and the shorter the growth period. Later sowing dates delayed growth cessation but also shortened the growth period. The mean CNL of the southern ecotype was longer, 6.3 ± 0.2 h (95 % confidence interval), than that of the northern ecotype, 3.1 ± 0.3 h. Within-ecotype variance of the CNL was higher in the northern ecotype (0.484 h2) than in the southern ecotype (0.150 h2). Browsing by moose decreased with increasing latitude of seed origin and sapling height. Origins transferred from more southern latitudes were more heavily browsed than the more northern native ones. Southern Finnish seed origins produced the highest volume per unit area in central Finland (lat. 63º11'N). Estonian and north Latvian stand seed origins, and the southern Finnish plus tree origins, were the most productive ones in southern Finland (lat. 60º21'N). Latitudinal seed transfer distance had a significant effect on survival, stem volume/ha and proportion of trees with a stem defect. The relationship of both survival and stem volume/ha to the latitudinal seed transfer distance was curvilinear. Volume was increased by transferring seed from ca. 2 degrees of latitude from the south. A longer transfer from the south, and transfer from the north, decreased the yield. The proportion of trees with a stem defect increased linearly in relation to the latitudinal seed transfer distance from the south.

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In this thesis we present and evaluate two pattern matching based methods for answer extraction in textual question answering systems. A textual question answering system is a system that seeks answers to natural language questions from unstructured text. Textual question answering systems are an important research problem because as the amount of natural language text in digital format grows all the time, the need for novel methods for pinpointing important knowledge from the vast textual databases becomes more and more urgent. We concentrate on developing methods for the automatic creation of answer extraction patterns. A new type of extraction pattern is developed also. The pattern matching based approach chosen is interesting because of its language and application independence. The answer extraction methods are developed in the framework of our own question answering system. Publicly available datasets in English are used as training and evaluation data for the methods. The techniques developed are based on the well known methods of sequence alignment and hierarchical clustering. The similarity metric used is based on edit distance. The main conclusions of the research are that answer extraction patterns consisting of the most important words of the question and of the following information extracted from the answer context: plain words, part-of-speech tags, punctuation marks and capitalization patterns, can be used in the answer extraction module of a question answering system. This type of patterns and the two new methods for generating answer extraction patterns provide average results when compared to those produced by other systems using the same dataset. However, most answer extraction methods in the question answering systems tested with the same dataset are both hand crafted and based on a system-specific and fine-grained question classification. The the new methods developed in this thesis require no manual creation of answer extraction patterns. As a source of knowledge, they require a dataset of sample questions and answers, as well as a set of text documents that contain answers to most of the questions. The question classification used in the training data is a standard one and provided already in the publicly available data.

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This study is a systematic analysis of mediated immediacy in the production of the Brazilian professor of theology João Batista Libanio. He stresses both ethical mediation and the immediate character of the faith. Libanio has sought an answer to the problem of science and faith. He makes use of the neo-scholastic distinction between matter and form. According to St. Thomas Aquinas, God cannot be known as a scientific object, but it is possible to predicate a formal theological content of other subject matter with the help of revelation. This viewpoint was emphasized in neo-Thomism and supported by the liberation theologians. For them, the material starting point was social science. It becomes a theologizable or revealable (revelabile) reality. This social science has its roots in Latin American Marxism which was influenced by the school of Louis Althusser and considered Marxism a science of history . The synthesis of Thomism and Marxism is a challenge Libanio faced, especially in his Teologia da libertação from 1987. He emphasized the need for a genuinely spiritual and ethical discernment, and was particularly critical of the ethical implications of class struggle. Libanio s thinking has a strong hermeneutic flavor. It is more important to understand than to explain. He does not deny the need for social scientific data, but that they cannot be the exclusive starting point of theology. There are different readings of the world, both scientific and theological. A holistic understanding of the nature of religious experience is needed. Libanio follows the interpretation given by H. C. de Lima Vaz, according to whom the Hegelian dialectic is a rational circulation between the totality and its parts. He also recalls Oscar Cullmann s idea of God s Kingdom that is already and not yet . In other words, there is a continuous mediation of grace into the natural world. This dialectic is reflected in ethics. Faith must be verified in good works. Libanio uses the Thomist fides caritate formata principle and the modern orthopraxis thinking represented by Edward Schillebeeckx. One needs both the ortho of good faith and the praxis of the right action. The mediation of praxis is the mediation of human and divine love. Libanio s theology has strong roots in the Jesuit spirituality that places the emphasis on contemplation in action.

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Lignin is a complex plant polymer synthesized through co-operation of multiple intracellular and extracellular enzymes. It is deposited to plant cell walls in cells where additional strength or stiffness are needed, such as in tracheary elements (TEs) in xylem, supporting sclerenchymal tissues and at the sites of wounding. Class III peroxidases (POXs) are secreted plant oxidoreductases with implications in many physiological processes such as the polymerization of lignin and suberin and auxin catabolism. POXs are able to oxidize various substrates in the presence of hydrogen peroxide, including lignin monomers, monolignols, thus enabling the monolignol polymerization to lignin by radical coupling. Trees produce large amounts of lignin in secondary xylem of stems, branches and roots. In this study, POXs of gymnosperm and angiosperm trees were studied in order to find POXs which are able to participate in lignin polymerization in developing secondary xylem i.e. are located at the site of lignin synthesis in tree stems and have the ability to oxidize monolignol substrates. Both in the gymnosperm species, Norway spruce and Scots pine, and in the angiosperm species silver birch the monolignol oxidizing POX activities originating from multiple POX isoforms were present in lignifying secondary xylem in stems during the period of annual growth. Most of the partially purified POXs from Norway spruce and silver birch xylem had highest oxidation rate with coniferyl alcohol, the main monomer in guaiacyl-lignin in conifers. The only exception was the most anionic POX fraction from silver birch, which clearly preferred sinapyl alcohol, the lignin monomer needed in the synthesis of syringyl-guaiacyl lignin in angiosperm trees. Three full-length pox cDNAs px1, px2 and px3 were cloned from the developing xylem of Norway spruce. It was shown that px1 and px2 are expressed in developing tracheids in spruce seedlings, whereas px3 transcripts were not detected suggesting low transcription level in young trees. The amino acid sequences of PX1, PX2 and PX3 were less than 60% identical to each other but showed up to 84% identity to other known POXs. They all begin with predicted N-terminal secretion signal (SS) peptides. PX2 and PX3 contained additional putative vacuolar localization determinants (VSDs) at C-terminus. Transient expression of EGFP-fusions of the SS- and VSD-peptides in tobacco protoplasts showed SS-peptides directed EGFP to secretion in tobacco cells, whereas only the PX2 C-terminal peptide seems to be a functional VSD. According to heterologous expression of px1 in Catharanthus roseus hairy roots, PX1 is a guaicol-oxidizing POX with isoelectric point (pI) approximately 10, similar to monolignol oxidizing POXs in protein extracts from Norway spruce lignifying xylem. Hence, PX1 has characteristics for participation to monolignol dehydrogenation in lignin synthesis, whereas the other two spruce POXs seem to have some other functions. Interesting topics in future include functional characterization of syringyl compound oxidizing POXs and components of POX activity regulation in trees.

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The aim of this study has been to analyze measures adopted to counteract workplace bullying from the perspective of human resource management. First, the kind of measures that are adopted to prevent bullying were examined. Second, factors affecting the extent of such measures were explored. The introduction of written anti-bullying policies and the provision of information were found to be the most common measures adopted. The policies strongly emphasized the role of supervisors and the immediate superior. Measures to counteract bullying were positively related to the adoption of ‘sophisticated’ human resource practices, previous negative publicity concerning bullying and the presence of a young human resource manager. The results, however, also indicated that imitation seemed to provide an important impetus behind anti-bullying efforts.

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This dissertation is a narrative account of the negotiations concerning the question of the Far East and the Shandong issue at the Washington Conference, leading to treaties, agreements and resolutions. In this dissertation, a certain stress is laid on the interaction between the Conference and the internal situation in China, particularly concerning the question of the implications of the Conference for Cabinet politics in Peking. Through the narrative account of the Conference, the general aim is an attempt to reassess the achievements of the Washington Conference. Too often the Washington Conference has been viewed negatively. The political aim behind the legal framework was to open the door to China as a sovereign State member of the international community whose territorial integrity was internationally recognized, despite its chaotic internal situation. It is undeniable that the Washington Conference opened a new chapter in modern Chinese history. The violations of the agreements concerning China that occurred in the 1930s should not lead to the belief that these agreements were of no value. Peace may not be lasting and evolves according to circumstances; agreements are transitory, and new situations need new arrangements. This dissertation tries to demonstrate that the agreements in themselves were not the cause of their failure, but the failure was due to the lack of determination on the part of the Signatories Powers to defend them.

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What happens when sexuality is banned from IAT public discourse? This book shows how everyday sexual behaviour and morality were — or were not — affected by the Soviet censorship on sexuality. Based on autobiographies written by ordinary people from St. Petersburg, it presents the loves and lives of three generations. It describes perceptions of love, the life course of the Russian family, transmissions of sexual knowledge, informal and illegal practices and contrasting subcultures. By posing the 'man question', Anna Rotkirch argues that the postsocialist transformation has centred on the Russian man. By contrast, one of the strongest continuities in the Russian gender system concerns the ways of mothering.

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The aim of this thesis was to unravel the functional-structural characteristics of root systems of Betula pendula Roth., Picea abies (L.) Karst., and Pinus sylvestris L. in mixed boreal forest stands differing in their developmental stage and site fertility. The root systems of these species had similar structural regularities: horizontally-oriented shallow roots defined the horizontal area of influence, and within this area, each species placed fine roots in the uppermost soil layers, while sinker roots defined the maximum rooting depth. Large radial spread and high ramification of coarse roots, and the high specific root length (SRL) and root length density (RLD) of fine roots indicated the high belowground competitiveness and root plasticity of B. pendula. Smaller radial root spread and sparser branching of coarse roots, and low SRL and RLD of fine roots of the conifers could indicate their more conservative resource use and high association with and dependence on ectomycorrhiza-forming fungi. The vertical fine root distributions of the species were mostly overlapping, implying the possibility for intense belowground competition for nutrients. In each species, conduits tapered and their frequency increased from distal roots to the stem, from the stem to the branches, and to leaf petioles in B. pendula. Conduit tapering was organ-specific in each species violating the assumptions of the general vascular scaling model (WBE). This reflects the hierarchical organization of a tree and differences between organs in the relative importance of transport, safety, and mechanical demands. The applied root model was capable of depicting the mass, length and spread of coarse roots of B. pendula and P. abies, and to the lesser extent in P. sylvestris. The roots did not follow self-similar fractal branching, because the parameter values varied within the root systems. Model parameters indicate differences in rooting behavior, and therefore different ecophysiological adaptations between species.

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Male flowering was studied at the canopy level in 10 silver birch (Betula pendula Roth) stands from 8 localities and in 14 downy birch (B. pubescens Ehrh.) stands from 10 localities in Finland from 1963 to 1973. Distributions of cumulative pollen catches were compared to the normal Gaussian distribution. The basis for the timing of flowering was the 50 per cent point of the anthesis-fitted normal distribution. To eliminate effects of background pollen, only the central, normally distributed part of the cumulative distribution was used. Development up to the median point of the distribution was measured and tested in calendar days, in degree days (> 5 °C) and in period units. The count of each parameter began on and included March 19. Male flowering in silver birch occurred from late April to late June depending on latitude, and flowering in downy birch took place from early May to early July. The heat sums needed for male flowering varied in downy birch stands latitudinally but there was practically no latitudinal variation in heat sums needed for silver birch flowering. The amount of male flowering in stands of both birch species were found to have a large annual variation but without any clear periodicity. The between years pollen catch variation in stands of either birch species did not show any significant latitudinal correlation in contrast to Norway spruce stands. The period unit heat sum gave the most accurate forecast of the timing of flowering for 60 per cent of the silver birch stands and for 78.6 per cent of the for downy birch stands. Calendar days, however, gave the best forecast for silver birch in 25 per cent of the cases, while degree days gave the best forecast for downy birch in 21.4 per cent of the cases. Silver birch seems to have a local inclination for a more fixed flowering date compared to downy birch, which could mean a considerable photoperiodic influence on flowering time of silver birch. Silver birch and downy birch had different geographical correlations. Frequent hybridization of birch species occurs more often in northern Finland in than in more southern latitudes. The different timing in flowering caused increasing scatter in flowering times in the north, especially in the case of downy birch. The chance of simultaneous flowering of silver birch and downy birch so increased northwards due to a more variable climate and also higher altitudinal variations. Compared with conifers, the reproduction cycles of both birch species were found to be well protected from damage by frost.