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Tulasnella species (Tulasnellaceae, Cantharellales, Basidiomycota) form inconspicuous basidiomata on rotten branches or trunks of trees, difficult to find and recognize in nature. However, according to ultrastrucural and molecular data, species of Tulasnellaceae are the most frequent mycorrhriza forming fungi (mycobionts) of green, photosynthetic orchids worldwide. Species of Tulasnellaceae were also found as prominent mycobionts of the extraordinary diverse orchids in tropical montane rainforest of Southern Ecuador. Orchids obligately depend on mycobionts during the juvenile stage when the fungi have to deliver carbon to the non-photosynthetic protocorm and thus the fungi substantially influence the establishment of orchids in the wild. Species of Tulasnellaceae can acquire carbon from decaying bark or wood by specific saprotrophic capabilities as was recently proven through comparative genomics that included data on decay enzymes from Tulasnella cf. calospora isolated from orchid mycorrhizae (Anacamptis laxiflora, Italy). Thus, species of Tulasnellaceae can be saprotrophs and symbionts simultaneously.
It is currently under discussion, whether specific species of Tulasnella are required for seed germination and establishment of distinct terrestrial and epiphytic orchids in nature or if species of Tulasnella are generalists concerning their association with orchids. The inconsistences in species concepts and taxonomy of Tulasnella spp., however, strongly impede progress in this field of research. The aim of the present study was, therefore, to revise the species concepts by combining, for the first time, morphological and molecular data from basidiomata.
Specimens were collected in tropical Andean forest in Southern Ecuador and in temperate forests in Germany. Additional specimens were loaned from fungaria. In total, 205 specimens, corresponding to 16 own samples and 189 specimens from fungaria were analyzed. The mycobiont relationships of Tulasnella spp. with orchids from the sampling area in Ecuador were studied in populations of Epidendrum rhopalostele. The basis for molecular-phylogenetic analysis was completed by data obtained from own previous investigations on mycobionts from the investigation area and Tulasnella isolates from Australia.
30 morphospecies are illustrated and delimited by a morphological key based on traditional species concepts. Tulasnella andina from Ecuador and Tulasnella kirschneri from China are presented as species new to science. Tulasnella cruciata is described from herbarium material for the first time. Tulasnella aff. eichleriana and T. violea are reported for the first time from Ecuador. Molecular sequences of two Tulasnella spp. isolated from mycobionts of Epidendrum rhopalostele cannot be related to any morphological species concept. Statistical analyses suggest that conventional diagnostic using morphological characteristics is ambiguous for delimiting morphologically similar species.
For the first time sequences of the ITS-5.8S rDNA region were obtained after cloning from fresh basidiomata. Extraction of DNA from herbarium specimens was, however, unsuccessful. Sequences from 16 fresh basidiomata, six pure cultures, and sequences of orchids mycorrhizae (e.g. from Epidendrum rhopalostele) available in the database GenBank were analyzed. Proportional
variability of ITS-5.8S rDNA sequences within and among cultures and within and among specimens were used to designate morphospecies. Results suggest an intragenomic variation of less than 2 %, an intraspecific variation of up to 4 % and an interspecific divergence of more than 9 % for Tulasnella spp.
Four percent of intraspecific divergence was defined as a minimum threshold for delimiting phylogenetic species. This threshold corroborates the so far used 3 % to 5 % divergence in delimitation of operational taxonomic units of Tulasnella mycobionts.
Quite a number of sequences of Tulasnella are available in GenBank, mostly obtained from direct PCR amplification from orchid mycorrhizae. By including closely related sequences in the phylogenetic analysis, several morphological cryptic species of Tulasnella, mostly from Ecuador, were found. Arguments are given for molecular support of the new species Tulasnella andina and the established species Tulasnella albida, T. asymmetrica, T. eichleriana, T. tomaculum, and T. violea. Thus, by combining molecular and morphological data species concepts in Tulasnella are improved. The definitions of Tulasnella calospora and T. deliquescens, however, remain phylogenetically inconsistent.
The present investigation is a first step to expand our knowledge on the intraand interspecific morphological and molecular variability of Tulasnella spp. and to delimit species relevant for studies on ecology and communities of orchids and Tulasnellaceae.
The recent financial crisis has demonstrated that a failure of Systemically Important Financial Institutions (SIFIs) could seriously damage the stability of the financial system. A precise and consistent definition of a SIFI is pivotal to ensure efficient and effective regulation of the global financial sector. This paper proposes a threefold test logic that allows to classify Financial Institutions as systemically important across the various industry segments.
We provide a comprehensive analysis of the determinants of trading in the sovereign credit default swaps (CDS) market, using weekly data for single-name sovereign CDS from October 2008 to September 2015. We describe the anatomy of the sovereign CDS market, derive a law of motion for gross positions and their components, and identify the key factors that drive the cross-sectional and time-series properties of trading volume and net notional amounts outstanding. While a single principal component accounts for 54 percent of the variation in sovereign CDS spreads, the largest common factor explains only 7 percent of the variation in sovereign CDS net notional amounts outstanding. Moreover, unlike for CDS spreads, common global factors explain very little of the variation in sovereign CDS trading and net notional amounts outstanding, suggesting that it is driven primarily by idiosyncratic country risk. We analyze several local and regional channels that may explain the trading in sovereign CDS: (a) country-specific credit risk shocks, including changes in a country's credit rating and related outlook changes, (b) the announcement and issuance of domestic and international debt, (c) macroeconomic sentiment derived from conventional and unconventional monetary policy, macro-economic news and shocks, and (d) regulatory channels, such as changes in bank capital adequacy requirements. All our findings suggest that sovereign CDS are more likely used for hedging than for speculative purposes.
Using novel monthly data for 226 euro-area banks from 2007 to 2015, we investigate the determinants of changes in banks’ sovereign exposures and their effects during and after the crisis. First, public, bailed out and poorly capitalized banks responded to sovereign stress by purchasing domestic public debt more than other banks, with public banks’ purchases growing especially in coincidence with the largest ECB liquidity injections. Second, bank exposures significantly amplified the transmission of risk from the sovereign and its impact on lending. This amplification of the impact on lending does not appear to arise from spurious correlation or reverse causality.
The euro crisis was fueled by the diabolic loop between sovereign risk and bank risk, coupled with cross-border flight-to-safety capital flows. European Safe Bonds (ESBies), a union-wide safe asset without joint liability, would help to resolve these problems. We make three contributions. First, numerical simulations show that ESBies would be at least as safe as German bunds and approximately double the supply of euro safe assets when protected by a 30%-thick junior tranche. Second, a model shows how, when and why the two features of ESBies — diversification and seniority — can weaken the diabolic loop and its diffusion across countries. Third, we propose a step-by-step guide on how to create ESBies, starting with limited issuance by public or private-sector entities.
How do insiders trade?
(2016)
We characterize how informed investors trade in the options market ahead of corporate news when they receive private, but noisy, information about (i) the timing of the announcement and (ii) its impact on stock prices. Our theoretical framework generates a rich set of predictions about the insiders’ behavior and their maximum expected returns. Three different analyses offer empirical support for our approach. First, predicted trades resemble illegal insider trades documented in SEC litigation cases with insiders being more likely to trade in options that offer higher expected returns. Second, pre-announcement patterns in unusual activity in the options market ahead of significant corporate news are consistent with the predictions of our framework. We employ our approach to characterize informed trading ahead of twelve different types of news including the announcement of earnings, corporate guidance, M&As, product innovations, management changes, and analyst recommendations. Third, to address concerns that pre-announcement patterns are driven by speculation, we show that measures capturing trading activity in call (put) options with high expected returns predict significant positive (negative) corporate news in the aggregate cross-section.
Based on a unique data set of driving behavior we find direct evidence that private information has significant effects on contract choice and risk in automobile insurance. The number of car rides and the relative distance driven on weekends are significant risk factors. While the number of car rides and average speeding are negatively related to the level of liability coverage, the number of car rides and the relative distance driven at night are positively related to the level of first-party coverage. These results indicate multiple and counteracting effects of private information based on risk preferences and driving behavior.
Prestige and loan pricing
(2016)
We find that prestigious companies pay lower spreads and upfront fees on their loans despite the fact that prestige does not predict default risk over the life of the loan. Using survey data on firm-level prestige, we show that a one standard deviation increase in prestige reduces loan spreads by 6.18% per year and upfront fees by 22.86%. We identify causal effects (i) using fraud by industry peers as an instrument for borrower prestige and (ii) exploiting a regression discontinuity around rank 100 of the prestige survey. Banks that lend to prestigious firms attract more business afterwards compared to otherwise similar institutions. Moreover, the effect of prestige on upfront fees is particularly strong for new bank relationships. Our findings suggest that prestigious firms receive cheaper funding because the associated lending relationship helps banks establish valuable credentials they use to compete for future borrowers.
Data show that sovereign risk reduces liquidity, increases funding cost and risk of banks highly exposed to it. I build a model that rationalizes this fact. Banks act as delegated monitors and invest in risky projects and in risky sovereign bonds. As investors hear rumors of increased sovereign risk, they run the bank (via global games). Banks could rollover liquidity in repo market using government bonds as collateral, but as sovereign risk raises collateral values shrink. Overall banks’ liquidity falls (its cost increases) and so does banks’ credit. In this context noisy news (announcements with signal extraction) of consolidation policies are recessionary in the short run, as they contribute to investors and banks pessimism, and mildly expansionary in the medium run. The banks liquidity channel plays a major role in the fiscal transmission.
This paper uses recent legislation in Austria to establish a link between sovereign reputation and yield spreads. In 2009, Hypo Alpe Adria International, a bank previously co-owned by the regional government of Carinthia, had been nationalized by Austria’s central government in order to avoid a default triggering multi-billion Euro local government guarantees. In 2015, special legislation retroactively introduced collective action clauses allowing a haircut on both the bonds and the guarantees while avoiding formal default. We document that legislative and administrative action designed to partly abrogate the guarantees resulted in a loss of reputation, leading to higher yield spreads for sovereign debt. Our analysis of covered bonds uncovers an increase in yield spreads on the secondary market and a deterioration of primary market conditions.