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Santa Luzia (18º52´, 18º60´N; 24º41´, 24º48´W) is the smallest island (35 km2) in the Cape Verde archipelago1. Although uninhabited today, two families of goatherds lived on Santa Luzia until the mid-1960s. In 1990, together with the nearby islets of Branco and Raso, Santa Luzia was designated a Nature Reserve by law. The island is extremely arid and barren, with hills, stony plains and sand-dunes being the main features. The highest elevation reaches 395 m a.s.l. The vegetation is characterized by a single floristic zone (Duarte et al. 2008), dominated by drought resistant species such as Cistance phelipaea, Polycarpaea nivea, Zygophyllum simplex, Heliotropium ramisissimum, Frankenia ericifolia and Euphorbia tuckeyana (Schleich & Wuttke 1983, Dinis & Matos 1994, Sánchez Pinto et al. 2005). The northern shoreline of the island is characterized by steep cliffs, 10-30 m in height. The remaining shore consists of sandy beaches in the southern part and rocky beaches along the western, north-eastern and eastern coast of the island (Dinis & Matos 1994).
The onion thrips, Thrips tabaci LINDEMAN (Thys., Thripidae) is an important pest of field and greenhouse crops around the world. It causes damage directly through feeding and indirectly through the transmission of lethal plant viruses. It is difficult to control this pest with insecticides because of its small size and cryptic habits (LEWIS 1997). Entomopathogenic fungi are currently being investigated for the control of many important insect pests on various crops around the world, and some are commercially available. There are many studies on the efficacy of several entomopathogenic fungi on thrips. CARL (1975) reported that Neozygites parvispora (MACLEOD, TYRRELL & CARL) REMAUDIERE and KELLER has been found frequently on T. tabaci but under field conditions the fungus was less successful than in the greenhouse. In addition, Entomophthora thripidum SAMSON, RAMAKERS & OSWALD was found infecting T. tabaci in Netherlands, but in field trials the fungus failed to suppress thrips populations below the economic acceptable level (SAMSON et al. 1979). In laboratory studies, T. tabaci was susceptible to Verticillium lecanii (ZIMMERMANN) VIÉGAS, Beauveria bassiana (BALSAMO) VUILLEMIN, Metarhizium anisopliae (METSCH.) SOROKIN and Paecilomyces fumosoroseus (WIZE) BROWN & SMITH (GILLESPIE 1986, FRANSEN 1990). VESTERGAARD et al. (1995) and BROWNBRIDGE (1995) showed that B. bassiana, M. anisopliae and V. lecanii were more active against the western flower thrips, Frankliniella occidentalis (PERGANDE) than P. fumosoroseus or Paecilomyces farinosus (HOLM ex S.F. GRAY) BROWN & SMITH. HALL et al. (1994) and SAITO (1991) suggested that Hirsutella sp., P. fumosoroseus and B. bassiana may be useful in the management of the melon thrips, Thrips palmi KARNY. EKESI et al. (1998) stated that B. bassiana and M. anisopliae are highly pathogenic to the legume flower thrips, Megalurothrips sjostedti (TRYBORN). In the glasshouse, V. lecanii has been used successfully to control T. tabaci on cucumber (GILLESPIE 1986).VACANTE et al. (1994) noted that N. parvispora caused up to 60 per cent mortality in motile developmental stages of F. occidentalis and reduced the insect populationdensity. Under greenhouse conditions, M. anisopliae was found to be effective in reducing the population growth of F. occidentalis on cucumber (AZAIZEH et al. 2002). Whereas, MANIANIA et al. (2001) observed that M. anisopliae had the potential to control F. occidentalis on chrysanthemum. The studies of MANIANIA et al. (2003) indicated that M. anisopliae had a potential to control T. tabaci in the field. Akanthomyces, Aschersonia, Cordyceps, Hypocrella, Hynennostilbe and Torrubiella were never observed to control thrips. Therefore, this study was conducted to investigate the pathogenicity of different entomopathogenic fungi from Thailand against T. tabaci larvae under controlled climatic conditions in the laboratory.
The basic question is whether POSSESSOR and POSSESSUM are on the same level as the roles of VALENCE, two additional roles as it were. My research on POSSESSION has shown (Seiler 1981:7 ff.) that this is not the case, that there is a difference in principle between POSSESSION and VALENCE. However, there are multiple interactions between the two domains, and these interactions shall constitute the object of the following inquiry. It is hoped that this will contribute to a better understanding both of POSSESSION and of VALENCE.
Possessive constructions are grammatical constructions which contain two nominals and express that the referent of one of these nominals belongs to the other. The kind of relationship denoted by possessive constructions is not only that of ownership (1), as the term "possessive" might suggest, but also that of kinship (2), bodypart relationship (3), part/whole relationship (4) and similar relationships [...]. The following investigation will start with possessive constructions on phrase level, i.e. possessive phrases, and then deal with possessive constructions on clause level.
Positron creation in crossed-beam collisions of high-energy, fully stripped heavy ions is investigated within the coupled-channel formalism. In comparison with fixed-target collisions of highly stripped heavy-ion projectiles positron production probabilities are enhanced by more than one order of magnitude. The increase results from the possibility to excite electrons from the negative energy continuum into all bound states. The positron spectrum is shifted towards higher energies because of the absence of electron screening. Rutherford scattering as well as nuclear collisions with time delay are investigated. We also discuss the filling of empty bound states by electrons from pair-production processes.
Containment problems belong to the classical problems of (convex) geometry. In the proper sense, a containment problem is the task to decide the set-theoretic inclusion of two given sets, which is hard from both the theoretical and the practical perspective. In a broader sense, this includes, e.g., radii or packing problems, which are even harder. For some classes of convex sets there has been strong interest in containment problems. This includes containment problems of polyhedra and balls, and containment of polyhedra, which have been studied in the late 20th century because of their inherent relevance in linear programming and combinatorics.
Since then, there has only been limited progress in understanding containment problems of that type. In recent years, containment problems for spectrahedra, which naturally generalize the class of polyhedra, have seen great interest. This interest is particularly driven by the intrinsic relevance of spectrahedra and their projections in polynomial optimization and convex algebraic geometry. Except for the treatment of special classes or situations, there has been no overall treatment of that kind of problems, though.
In this thesis, we provide a comprehensive treatment of containment problems concerning polyhedra, spectrahedra, and their projections from the viewpoint of low-degree semialgebraic problems and study algebraic certificates for containment. This leads to a new and systematic access to studying containment problems of (projections of) polyhedra and spectrahedra, and provides several new and partially unexpected results.
The main idea - which is meanwhile common in polynomial optimization, but whose understanding of the particular potential on low-degree geometric problems is still a major challenge - can be explained as follows. One point of view towards linear programming is as an application of Farkas' Lemma which characterizes the (non-)solvability of a system of linear inequalities. The affine form of Farkas' Lemma characterizes linear polynomials which are nonnegative on a given polyhedron. By omitting the linearity condition, one gets a polynomial nonnegativity question on a semialgebraic set, leading to so-called Positivstellensaetze (or, more precisely Nichtnegativstellensaetze). A Positivstellensatz provides a certificate for the positivity of a polynomial function in terms of a polynomial identity. As in the linear case, these Positivstellensaetze are the foundation of polynomial optimization and relaxation methods. The transition from positivity to nonnegativity is still a major challenge in real algebraic geometry and polynomial optimization.
With this in mind, several principal questions arise in the context of containment problems: Can the particular containment problem be formulated as a polynomial nonnegativity (or, feasibility) problem in a sophisticated way? If so, how are positivity and nonnegativity related to the containment question in the sense of their geometric meaning? Is there a sophisticated Positivstellensatz for the particular situation, yielding certificates for containment? Concerning the degree of the semialgebraic certificates, which degree is necessary, which degree is sufficient to decide containment?
Indeed, (almost) all containment problems studied in this thesis can be formulated as polynomial nonnegativity problems allowing the application of semialgebraic relaxations. Other than this general result, the answer to all the other questions (highly) depends on the specific containment problem, particularly with regard to its underlying geometry. An important point is whether the hierarchies coming from increasing the degree in the polynomial relaxations always decide containment in finitely many steps.
We focus on the containment problem of an H-polytope in a V-polytope and of a spectrahedron in a spectrahedron. Moreover, we address containment problems concerning projections of H-polyhedra and spectrahedra. This selection is justified by the fact that the mentioned containment problems are computationally hard and their geometry is not well understood.
Various contemporary phenomena of social regression and authoritarianism are related to religious actors, movements, and beliefs. This text, however, seeks to follow this up with the political–theoretical argumentation that New Atheism has to be understood as a way of thinking which carries illiberal and authoritarian tendencies with it as well. In defence of this position, this article will first reconstruct, with reference to Habermas’s and Rawls’s theory of democracy, elements that must include personal beliefs in order to be considered congruent with democratic values. Subsequently, New Atheism’s conception of rational politics will be presented in order to show in which aspects it contradicts the demands of reasonable convictions. This concerns, in particular, the rejection of reasonable pluralism on the one hand and a non-positivistic view of human beings on the other. As a conclusion, this text supports the proposition that, when speaking of the connection between certain worldviews and today’s illiberalism, New Atheism must also be considered as an unreasonable comprehensive doctrine.
Understanding plant-plant interactions is essential in planning and implementing effective grassland management strategies. Positive and negative interactions generally co-occur in plant communities and the net effect of these interactions may depend on the disturbance regime, including grazing. Shrubs can act as biotic refuges by physically protecting neighbouring plants from herbivores. As a result, we would expect that in pastures the diversity and flowering success of plants is higher in the close vicinity of shrubs compared to the open vegetation. Nevertheless, we can also assume a competitive trade-off cost for plants that grow together with shrubs. In this study, we assessed the small-scale effects of dwarf shrubs (30–40 cm in diameter) on species density and flowering success. Specifically, we considered three types of microsites: (i) shrub interior, (ii) edge of shrub, and (iii) open pasture (more than 2 meters away from the shrub). We surveyed these three types of microsites using 10 × 10 cm sized plots both in grazed and ungrazed meadow steppe, in central Hungary. The highest species density was found at the edge of shrubs, both in grazed and ungrazed vegetation. Meanwhile, species density did not differ significantly between shrub interiors and the open pasture. However, in grazed vegetation, species flowering success was significantly higher in shrub interiors and edges than in the open pasture; no significant trend was observed for this measure in ungrazed vegetation. In contrast to previous studies, we did not detect a competitive effect of small-sized shrubs on plants in ungrazed vegetation. Our results indicate that small-sized shrubs protect other plants from herbivores and that the edge effect plays an important role for the maintenance of small-scale species diversity in pastures. Overall, our results underline the beneficial effect of biotic refuges in pastures and we suggest that retaining a sparse population of small-sized native shrubs is advantageous from a conservation point of view.