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A new species of the synthemistid genus Palaeosynthemis is described from the Trauna River valley in Western Highlands Province, Papua New Guinea. The new species is most similar to P. cyrene from which it can be distinguished, among other characters, by the coloration of the pterostigma (jet-black in the new species vs brownish yellow in P. cyrene) and of the wing bases (not darkened vs strongly darkened). The new species also differs from P. cyrene in having a narrow, almost parallel-sided yellow lateral synthoracic stripe and a well-defined yellow marking along most of the ventral margin of the metepimeron. In P. cyrene the lateral synthoracic stripe is markedly wider and tapered, and the yellow element along the ventral margin of the metepimeron is absent. Characters of the adult male are illustrated and the affinities of the species are discussed.
A selection of duplicates from the collection of Michel Edmond de Selys Longchamps was found at the Übersee-Museum Bremen/Germany (UMB). Selys determined a lot of Odonata in the UMB collection and sent 80 European and 76 exotic species to Bremen on 23 April, 1875. According to the labels 121 specimens could be assigned to this shipment and eleven specimens must have been sent to UMB in later years. This collection includes two paralectotypes (Progomphus gracilis Hagen inSelys, 1853;Palaemnema nathalia Selys, 1886) and seven syntypes (Rhinocypha trifasciata Selys, 1853; Dysphaea dimidiata limbata Selys, 1859; Argia sordida Hagen inSelys, 1865; Oxyagrion dissidens Selys, 1876; Oxyagrion haematinum Selys, 1876; Oxyagrion pavi-dum Hagen in Selys, 1876; Telagrion longum Selys, 1876). In addition, a male specimen of Euphaea tricolor subcostalis Selys, 1873 might also belong to the original syntype series. Altogether three specimens with labeled nomina nuda(Diplax catharina Selys, Diplax fausta Selys, Dythemis bilineata Hagen) and two labeled with manuscript names (Diplax marcellina Selys, Perithemis ovate Bates) are in this collection.
In spring and summer 2008, the Odonata fauna of the Khabr National Park (Iran) was studied for the first time. Here, we present records of the representatives of family Libellulidae only. A total of twelve libellulid Odonata were found. Most of them are common species in Iran and other parts of Kerman province. Scarce Iranian species are Trithemis arteriosa and Zygonyx torridus.
Specimens of Burmagomphus asahinai Kosterin, Makbun and Dawwrueng, 2012 and Burmagomphus divaricatus Lieftinck, 1964 from SW and NE Cambodia show differences in the development of the light pattern. One male of the latter species has unusual posterior spinules on posterior hamuli. Two males of Orientogomphus minor(Laidlaw, 1931) from the same locality in NE Cambodia have substantial differences in the thoracic and abdominal pattern. NE Cambodian specimens of Gomphidia abbotti Williamson, 1907 and Lamelligomphus castor (Lieftinck, 1941) have minor differences from data on these species from literature. Caution is necessary when composing and using keys for identification of the mentioned genera of gomphids.
Balut and Sarangani islands are two small landmasses situated off the coast of Davao Occidental, Mindanao Island. Despite recent increase on odonatological data from various islands in the Philippines, these two remote islands have never been explored. Hence, a short survey was conducted on first week of April and November 7 – November 14, 2010 on all freshwater systems in these two islands. Twenty-five species under seven families and 21 genera were found representing the first Odonata record for the two islands.
We propose a novel approach on how to estimate systemic risk and identify its key determinants. For US financial companies with publicly traded equity options, we extract option-implied value-at-risks and measure the spillover effects between individual company value-at-risks and the option-implied value-at-risk of a financial index. First, we study the spillover effect of increasing company risks on the financial sector. Second, we analyze which companies are mostly affected if the tail risk of the financial sector increases. Key metrics such as size, leverage, market-to-book ratio and earnings have a significant influence on the systemic risk profiles of financial institutions.
This thesis serves two main purposes:
1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids
2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions
1) The new method is established by the synergy of a liquid microjet of ~ 5 µm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments.
2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ~ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald’s rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation.
The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related.
In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are investigated. It is found that the crystallization process starts earlier and lasts significantly longer compared to the pure substances with the maximum values between 20-50% ortho-deuterium content. A solely temperature based explanation for this effect can be excluded. The difference in the quantum character and hence effective size of the isotopes suggests a strong influence of the progressing liquid-solid-interface. Small dilutions of each para-hydrogen and ortho-deuterium with neon show an even more extended crystallization process compared to above isotopic mixtures. Additionally, the crystal is strongly altered in favor of the equilibrium lattice structure of neon.
Low interest rates are becoming a threat to the stability of the life insurance industry, especially in countries such as Germany, where products with relatively high guaranteed returns sold in the past still represent a prominent share of the total portfolio. This contribution aims to assess and quantify the effects of the current low interest rate phase on the balance sheet of a representative German life insurer, given the current asset allocation and the outstanding liabilities. To do so, we generate a stochastic term structure of interest rates as well as stock market returns to simulate investment returns of a stylized life insurance business portfolio in a multi-period setting. Based on empirically calibrated parameters, we can observe the evolution of the life insurers' balance sheet over time with a special focus on their solvency situation. To account for different scenarios and in order to check the robustness of our findings, we calibrate different capital market settings and different initial situations of capital endowment. Our results suggest that a prolonged period of low interest rates would markedly affect the solvency situation of life insurers, leading to relatively high cumulative probability of default for less capitalized companies.
This paper analyzes how on-the-job search (OJS) by an agent impacts the moral hazard problem in a repeated principal-agent relationship. OJS is found to constitute a source of agency costs because efficient search incentives require that the agent receives all gains from trade. Further, the optimal incentive contract with OJS matches the design of empirically observed compensation contracts more accurately than models that ignore OJS. In particular, the optimal contract entails excessive performance pay plus efficiency wages. Efficiency wages reduce the opportunity costs of work effort and hence serve as a complement to bonuses. Thus, the model offers a novel explanation for the use of efficiency wages. When allowing for renegotiation, the model generates wage and turnover dynamics that are consistent with empirical evidence. I argue that the model contributes to explaining the concomitant rise in the use of performance pay and in competition for high-skill workers during the last three decades.
We study consumption-portfolio and asset pricing frameworks with recursive preferences and unspanned risk. We show that in both cases, portfolio choice and asset pricing, the value function of the investor/ representative agent can be characterized by a specific semilinear partial differential equation. To date, the solution to this equation has mostly been approximated by Campbell-Shiller techniques, without addressing general issues of existence and uniqueness. We develop a novel approach that rigorously constructs the solution by a fixed point argument. We prove that under regularity conditions a solution exists and establish a fast and accurate numerical method to solve consumption-portfolio and asset pricing problems with recursive preferences and unspanned risk. Our setting is not restricted to affine asset price dynamics. Numerical examples illustrate our approach.