A consistent econometric test for bid interdependence in repeated second-price auctions with posted prices

In repeated second-price experimental auctions, the winning bid is normally posted after each round. The posting of these winning prices after each round can result in bids submitted in later rounds to be interdependent with posted prices from earlier rounds. Several approaches in the past have tried to scrutinize their experimental data for value interdependence by regressing bids on lagged market prices or lagged bids and ignoring the inherent endogeneity problem. This paper introduces a formal test for bid interdependence in repeated second-price auctions with posted prices using a dynamic panel model. We then apply this test to formally check the presence of bid interdependence in three datasets used in previous studies.experimental auctions; bid interdependence; dynamic panel estimator; second-price auction

Small RNA-guided processes in the hyperthermophilic methanogen Methanopyrus kandleri

In this thesis, a combination of RNAseq, computational and biochemical methods was applied to analyze processes that use small RNAs (sRNAs) as guide molecules at extreme temperatures. Here, the hyperthermophilic archaeon Methanopyrus kandleri, which grows at temperatures of up to 110°C, was used as a model organism. The genome of M. kandleri harbors two CRISPR-Cas systems that use CRISPR RNA (crRNA) as guide molecules to target foreign nucleic acids. RNAseq analysis revealed a high abundance and processing of crRNAs in M. kandleri that indicated that CRISPR-Cas systems are highly active at extreme temperatures. Furthermore, the crystal structure of the CRISPR-associated protein Csm3 was solved in collaboration with Prof. Dr. Elena Conti (MPI Martinsried). Csm3 was found to bind crRNAs and was shown to function as the crRNA-binding backbone protein in type III-A CRISPR-Cas interference complexes. A recently discovered nucleic acid-guided mechanism uses prokaryotic Argonaute (pAgo) proteins. In M. kandleri, a pAgo protein was found to be encoded within a potential operon of CRISPR-associated genes and the analysis of recombinant pAgo protein production revealed a high toxicity in Escherichia coli that might correlate with its potential defense function against plasmid DNA. Methylation of rRNA is regulated by a different sRNA-guided mechanism that utilizes C/D box sRNAs to target a ribonucleoprotein complex to the rRNA methylation site. In M. kandleri, a record number of 126 C/D box sRNAs were detected by RNAseq analysis and indicate an increased potential for rRNA methylation reactions. Furthermore, most of the C/D box sRNAs were detected as circular molecules. Taken together, the circularization of C/D box sRNAs and the high requirement for rRNA methylation are suggested to be adaptations to the hyperthermophilic lifestyle of M. kandleri. Finally, RNAseq analyses were used to identify tRNA precursors in M. kandleri that feature a unique C-to-U editing reaction of base 8. The occurrence of this editing event was used to deduce the order of tRNA processing steps in a non-compartmentalized cell, indicating that termini truncation precedes intron removal and editing

Emergent spin-1 trimerized valence bond crystal in the spin-1/2 Heisenberg model on the star lattice

We explore the frustrated spin-$1/2$ Heisenberg model on the star lattice with antiferromagnetic (AF) couplings inside each triangle and ferromagnetic (FM) inter-triangle couplings ($J_e<0$), and calculate its magnetic and thermodynamic properties. We show that the FM couplings do not sabotage the magnetic disordering of the ground state due to the frustration from the AF interactions inside each triangle, but trigger a fully gapped inversion-symmetry-breaking trimerized valence bond crystal (TVBC) with emergent spin-1 degrees of freedom. We discover that with strengthening $J_e$, the system scales exponentially, either with or without a magnetic field $h$: the order parameter, the five critical fields that separate the $J_e$-$h$ ground-state phase diagram into six phases, and the excitation gap obtained by low-temperature specific heat, all depend exponentially on $J_e$. We calculate the temperature dependence of the specific heat, which can be directly compared with future experiments.Comment: 7 pages, 6 figure

Geoengineered ocean vertical water exchange can accelerate global deoxygenation

Ocean deoxygenation is a threat to marine ecosystems. We evaluated the potential of two ocean intervention technologies, i.e. “artificial downwelling (AD)” and “artificial upwelling (AU)”, for remedying the expansion of Oxygen Deficient Zones (ODZs). The model‐based assessment simulated AD and AU implementations for 80 years along the eastern Pacific ODZ. When AD was simulated by pumping surface seawater to the 178 ~ 457 m depth range of the ODZ, vertically integrated oxygen increased by up to 4.5% in the deployment region. Pumping water from 457 m depth to the surface (i.e. AU), where it can equilibrate with the atmosphere, increased the vertically integrated oxygen by 1.03%. However, both simulated AD and AU increased biological production via enhanced nutrient supply to the sea surface, resulting in enhanced export production and subsequent aerobic remineralization also outside of the actual implementation region, and an ultimate net decline of global oceanic oxygen

What prevents nitrogen depletion in the oxygen minimum zone of the eastern tropical South Pacific?

Local coupling between nitrogen fixation and denitrification in current biogeochemical models could result in runaway feedback in open-ocean oxygen minimum zones (OMZs), eventually stripping OMZ waters of all fixed nitrogen. This feedback does not seem to operate at full strength in the ocean, as nitrate does not generally become depleted in open-ocean OMZs. To explore in detail the possible mechanisms that prevent nitrogen depletion in the OMZ of the eastern tropical South Pacific (ETSP), we develop a box model with fully prognostic cycles of carbon, nutrients and oxygen in the upwelling region and its adjacent open ocean. Ocean circulation is calibrated with Δ14C data of the ETSP. The sensitivity of the simulated nitrogen cycle to nutrient and oxygen exchange and ventilation from outside the model domain and to remineralization scales inside an OMZ is analysed. For the entire range of model configurations explored, we find that the fixed-N inventory can be stabilized at non-zero levels in the ETSP OMZ only if the remineralization rate via denitrification is slower than that via aerobic respiration. In our optimum model configuration, lateral oxygen supply into the model domain is required at rates sufficient to oxidize at least about one fifth of the export production in the model domain to prevent anoxia in the deep ocean. Under these conditions, our model is in line with the view of phosphate as the ultimate limiting nutrient for phytoplankton, and implies that for the current notion of nitrogen fixation being favoured in N-deficit waters, the water column of the ETSP could even be a small net source of nitrate

10151 Abstracts Collection -- Enabling Holistic Approaches to Business Process Lifecycle Management

From 11.04. to 16.04.2010, the Dagstuhl Seminar 10151 ``Enabling Holistic Approaches to Business Process Lifecycle Management \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available