mic Efficiency and Pareto Optimality in a Stochastic OLG Model with Production and Social Security

We analyze the interaction between risk sharing and capital accumulation in a stochastic OLG model with production. We give a complete characterization of interim Pareto optimality. Our characterization also subsumes equilibria with a PAYG social security system. In a competitive equilibrium interim Pareto optimality is equivalent to intergenerational exchange efficiency, which in turn implies dynamic efficiency. Furthermore, dynamic efficiency does not rule out a Pareto-improving role for a social security system. Social security can provide insurance against macroeconomic risk, namely aggregate productivity risk in the second period of life (old age) through dynamic risk sharing. We briefly relate our results to models without uncertainty where the notions of exchange efficiency, dynamic efficiency and interim Pareto optimality are all equivalent in a competitive equilibrium.Stochastic OLG Model, Dynamic Efficiency, Interim Pareto Optimality, Social Security, Risk Sharing

The Zilcha criteria for dynamic inefficiency reconsidered

We reconsider necessary and sufficient conditions for dynamic inefficiency given in Zilcha (J Econ Theory 52:364-379, 1990, J Econ Theory 55:1-16, 1991) and a critique by Rangazas and Russell (2005). First, we show that the characterization given in Zilcha (1990) for nonstationary economies is correct and correct Zilcha's proof. Second, using this insight, we complement Rangazas and Russell's (Econ Theory 26:701-716, 2005) discussion of the counterexamples to Zilcha (J Econ Theory 55:1-16, 1991). Third, we discuss consequences of our results for applied tests of (in-)efficiency based on the Zilcha criteri

Fabrication of wide-IF 200–300 GHz superconductor–insulator–superconductor mixers with suspended metal beam leads formed on silicon-on-insulator

We report on a fabrication process that uses SOI substrates and micromachining techniques to form wide-IF SIS mixer devices that have suspended metal beam leads for rf grounding. The mixers are formed on thin 25 µm membranes of Si, and are designed to operate in the 200–300 GHz band. Potential applications are in tropospheric chemistry, where increased sensitivity detectors and wide-IF bandwidth receivers are desired. They will also be useful in astrophysics to monitor absorption lines for CO at 230 GHz to study distant, highly redshifted galaxies by reducing scan times. Aside from a description of the fabrication process, electrical measurements of these Nb/Al–AlNx/Nb trilayer devices will also be presented. Since device quality is sensitive to thermal excursions, the new beam lead process appears to be compatible with conventional SIS device fabrication technology

Decentralized Identities for Self-sovereign End-users (DISSENS)

This paper describes a comprehensive architecture and reference implementation for privacy-preserving identity management that bucks the trend towards centralization present in contemporary proposals. DISSENS integrates a technology stack which combines privacy-friendly online payments with self-sovereign personal data management using a decentralized directory service. This enables users to be in complete control of their digital identity and personal information while at the same time being able to selectively share information necessary to easily use commercial services. Our pilot demonstrates the viability of a sustainable, user-centric, standards-compliant and accessible use case for public service employees and students in the domain of retail e-commerce. We leverage innovative technologies including self-sovereign identity, privacy credentials, and privacy-friendly digital payments in combination with established standards to provide easy-to-adapt templates for the integration of various scenarios and use cases

Adjuvant radiotherapy improves progression-free survival in intracranial atypical meningioma

BACKGROUND: Meningiomas are the most common primary tumors of the central nervous system. In patients with WHO grade I meningiomas no adjuvant therapy is recommended after resection. In case of anaplastic meningiomas (WHO grade III), adjuvant fractionated radiotherapy is generally recommended, regardless of the extent of surgical resection. For atypical meningiomas (WHO grade II) optimal postoperative management has not been clearly defined yet. METHODS: We conducted a retrospective analysis of patients treated for intracranial atypical meningioma at Charité Universitätsmedizin Berlin from March 1999 to October 2018. Considering the individual circumstances (risk of recurrence, anatomical location, etc.), patients were either advised to follow a wait-and-see approach or to undergo adjuvant radiotherapy. Primary endpoint was progression-free survival (PFS). RESULTS: This analysis included 99 patients with atypical meningioma (WHO grade II). Nineteen patients received adjuvant RT after primary tumor resection (intervention group). The remaining 80 patients did not receive any further adjuvant therapy after surgical resection (control group). Median follow-up was 37 months. Median PFS after primary resection was significantly longer in the intervention group than in the control group (64 m vs. 37 m, p = 0.009, HR = 0.204, 95% CI = 0.062-0.668). The influence of adjuvant RT was confirmed in multivariable analysis (p = 0.041, HR = 0.192, 95% CI = 0.039-0.932). CONCLUSIONS: Our study adds to the evidence that RT can improve PFS in patients with atypical meningioma

Gauge-Invariant Operators for Singular Knots in Chern-Simons Gauge Theory

We construct gauge invariant operators for singular knots in the context of Chern-Simons gauge theory. These new operators provide polynomial invariants and Vassiliev invariants for singular knots. As an application we present the form of the Kontsevich integral for the case of singular knots.Comment: 44 pages, latex, 16 figure

Polynomials for Torus Links from Chern-Simons Gauge Theories

Invariant polynomials for torus links are obtained in the framework of the Chern-Simons topological gauge theory. The polynomials are computed as vacuum expectation values on the three-sphere of Wilson line operators representing the Verlinde algebra of the corresponding rational conformal field theory. In the case of the $SU(2)$ gauge theory our results provide explicit expressions for the Jones polynomial as well as for the polynomials associated to the $N$-state ($N>2$) vertex models (Akutsu-Wadati polynomials). By means of the Chern-Simons coset construction, the minimal unitary models are analyzed, showing that the corresponding link invariants factorize into two $SU(2)$ polynomials. A method to obtain skein rules from the Chern-Simons knot operators is developed. This procedure yields the eigenvalues of the braiding matrix of the corresponding conformal field theory.Comment: 50 page

Extreme Value Statistics and Traveling Fronts: Various Applications

An intriguing connection between extreme value statistics and traveling fronts has been found recently in a number of diverse problems. In this brief review we outline a few such problems and consider their various applications.Comment: A brief review (6 pages, 2 figures) to appear in Physica A as part of the proceedings of Statphys-Kolkata IV (2002

Talking Different Languages: The Role of Plant-Plant Communication When an Invader Beats up a Strange Neighborhood

Communication through airborne volatile organic compounds (VOCs) and root exudates plays a vital role in the multifarious interactions of plants. Common ragweed (Ambrosia artemesiifolia L.) is one of the most troublesome invasive alien species in agriculture. Below- and aboveground chemical interactions of ragweed with crops might be an important factor in the invasive species' success in agriculture. In laboratory experiments, we investigated the contribution of intra- and interspecific airborne VOCs and root exudates of ragweed to its competitiveness. Wheat, soybean, and maize were exposed to VOCs emitted from ragweed and vice versa, and the adaptation response was measured through plant morphological and physiological traits. We observed significant changes in plant traits of crops in response to ragweed VOCs, characterized by lower biomass production, lower specific leaf area, or higher chlorophyll contents. After exposure to ragweed VOCs, soybean and wheat produced significantly less aboveground dry mass, whereas maize did not. Ragweed remained unaffected when exposed to VOCs from the crops or a conspecific. All crops and ragweed significantly avoided root growth toward the root exudates of ragweed. The study shows that the plant response to either above- or belowground chemical cues is highly dependent on the identity of the neighbor, pointing out the complexity of plant-plant communication in plant communities