Dephasing-assisted Gain and Loss in Mesoscopic Quantum Systems

Motivated by recent experiments, we analyse the phonon-assisted steady-state gain of a microwave field driving a double quantum-dot in a resonator. We apply the results of our companion paper, which derives the complete set of fourth-order Lindblad dissipators using Keldysh methods, to show that resonator gain and loss are substantially affected by dephasing-assisted dissipative processes in the quantum-dot system. These additional processes, which go beyond recently proposed polaronic theories, are in good quantitative agreement with experimental observationsComment: 5 pages, 3 Figures, published together with arXiv:1608.0416

Corporate Tax Policy, Foreign Firm Ownership and Thin Capitalization

This paper analyzes the implications of foreign firm ownership and international profit shifting through thin capitalization for corporate tax policy. We consider a model of interjurisdictional tax competition where the corporate tax serves as a backstop to the personal income tax, interest on debt is deductible from the corporate tax base and multinational firms may shift profit across countries through thin capitalization. We show that the problem of thin capitalization induces countries to reduce their corporate tax rates below the personal income tax rate and to broaden their tax bases. Moreover, foreign firm ownership leads to a reduction in corporate tax rates. We also show that there is scope for welfare enhancing tax coordination in our model. In the presence of both foreign firm ownership and thin capitalization, countries gain from a coordinated increase in corporate tax rates or from a coordinated broadening of the tax base.tax competition, income shifting

Changes in the fledging success over time with increasing population size in the Northern Lapwing Vanellus vanellus on Wangerooge Island (Lower Saxony, Germany)

In this study, we report the results of a long-term investigation on changes in population size and fledging success of Northern Lapwing on Wangerooge, a German Wadden Sea island. This population is increasing over a period of 34 years in contrast to numerous populations in North-western Europe. The reproductive success however declines over time and also with population density. Both effects cannot be considered separately due to autocorrelation. However, it is noted that the population on Wangerooge is not sustained by local recruitment only. This outcome is even more alarming as coastal areas and islands are considered as rare high quality meadow bird habitats. According to the present results Wangerooge cannot be considered as a source habitat for Northern Lapwings in North-western Germany.Die vorliegende Langzeitstudie beschreibt die Bestandsentwicklung und den Reproduktionserfolg des Kiebitzes (Vanellus vanellus) auf der Nordseeinsel Wangerooge (Niedersachsen, Deutschland). In den vergangenen 34 Jahren hat der Kiebitzbestand hier kontinuierlich zugenommen. Diese Entwicklung unterscheidet sich damit deutlich von denen anderer Kiebitzpopulationen in Nord- und Westeuropa. Der Bruterfolg des Kiebitzes auf Wangerooge nahm im gleichen Zeitraum mehr und mehr ab. Er zeigte zudem einen negativen Trend mit steigender Populationsgröße. Leider können beide Effekte aufgrund von Autokorrelation statistisch nicht separiert werden. Der mittlere Bruterfolg ist allerdings keineswegs hoch genug, um die Population selbst zu tragen. Dies ist alarmierend, da die Nordseeinseln und angrenzende Küstengebiete als qualitativ hochwertige Wiesenvogellebensräume gelten. Da nach derzeitigem Kenntnisstand der Bruterfolg des Kiebitzes auf Wangerooge nicht bestandserhaltend ist, kann die Insel auch nicht als „source-Habitat“ für diese Limikolenart gelten

Logics with rigidly guarded data tests

The notion of orbit finite data monoid was recently introduced by Bojanczyk as an algebraic object for defining recognizable languages of data words. Following Buchi's approach, we introduce a variant of monadic second-order logic with data equality tests that captures precisely the data languages recognizable by orbit finite data monoids. We also establish, following this time the approach of Schutzenberger, McNaughton and Papert, that the first-order fragment of this logic defines exactly the data languages recognizable by aperiodic orbit finite data monoids. Finally, we consider another variant of the logic that can be interpreted over generic structures with data. The data languages defined in this variant are also recognized by unambiguous finite memory automata

Social accounting matrices and multiplier analysis: An introduction with exercises

This training guide introduces development practitioners, policy analysts, and students to social accounting matrices (SAMs) and their use in policy analysis. There are already a number of books that explain the System of National Accounts and SAM multipliers—some of these are recommended at the end of this training guide. However, most books tend to be quite technical and move quickly from an introduction to more complex applications. By contrast, this guidebook uses a series of hands-on exercises to gradually introduce SAMs and multiplier analysis. It therefore complements more theoretical SAM and multiplier literature and provides a first step for development practitioners and students wishing to understand the strengths and limitations of these economic tools. It is also useful for policy analysts and researchers embarking on more complex SAM-based methodologies. One such methodology is computable general equilibrium (CGE) modeling, for which IFPRI has also developed a series of introductory exercises and a standard modeling framework.Social Accounting Matrices (SAM's), Policy analysis, complex applications, multiplier analysis, Computable General Equilibrium (CGE) model,

Corporate Tax Reform and Foreign Direct Investment in Germany – Evidence from Firm-Level Data

Does the reduction of the effective tax burden on corporations trigger foreign direct investment? We take the German tax reform of 2000 as a natural experiment in order to isolate the impact of corporate taxation on the investment of foreign-held affiliates in Germany. We do so by exploiting the very rich MiDi data base from the Deutsche Bundesbank. Although we deliberately choose an approach which is likely to underestimate the tax effects on investment we find significant evidence that the tax reduction had the intended effect of - ceteris paribus - fostering inward direct investment. We find an elasticity of inward foreign direct investment with respect to the effective marginal tax rate of -0.7. We repeat the analysis for different subgroups and find high degrees of heterogeneity. Our results do not allow to decide whether the model of discrete investment choices or the model of marginal adjustment of the capital stock performs better in explaining the investment data.corporate taxation, foreign direct investment

Active suspension design for a Large Space Structure ground test facility

The expected future high performance requirements for Large Space Structures (LSS) enforce technology innovations such as active vibration damping techniques e.g., by means of structure sensors and actuators. The implementation of new technologies like that requires an interactive and integrated structural and control design with an increased effort in hardware validation by ground testing. During the technology development phase generic system tests will be most important covering verification and validation aspects up to the preparation and definition of relevant space experiments. For many applications using advanced designs it is deemed necessary to improve existing testing technology by further reducing disturbances and gravity coupling effects while maintaining high performance reliability. A key issue in this context is the improvement of suspension techniques. The ideal ground test facility satisfying these requirements completely will never be found. The highest degree of reliability will always be obtained by passive suspension methods taking into account severe performance limitations such as non-zero rigid body modes, restriction of degrees of freedom of motion and frequency response limitations. Passive compensation mechanisms, e.g., zero-spring-rate mechanisms, either require large moving masses or they are limited with respect to low-frequency performance by friction, stiction or other non-linear effects. With active suspensions these limitations can be removed to a large extent thereby increasing the range of applications. Despite an additional complexity which is associated with a potential risk in reliability their development is considered promising due to the amazing improvement of real-time control technology which is still continuing

The descriptive complexity approach to LOGCFL

Building upon the known generalized-quantifier-based first-order characterization of LOGCFL, we lay the groundwork for a deeper investigation. Specifically, we examine subclasses of LOGCFL arising from varying the arity and nesting of groupoidal quantifiers. Our work extends the elaborate theory relating monoidal quantifiers to NC1 and its subclasses. In the absence of the BIT predicate, we resolve the main issues: we show in particular that no single outermost unary groupoidal quantifier with FO can capture all the context-free languages, and we obtain the surprising result that a variant of Greibach's ``hardest context-free language'' is LOGCFL-complete under quantifier-free BIT-free projections. We then prove that FO with unary groupoidal quantifiers is strictly more expressive with the BIT predicate than without. Considering a particular groupoidal quantifier, we prove that first-order logic with majority of pairs is strictly more expressive than first-order with majority of individuals. As a technical tool of independent interest, we define the notion of an aperiodic nondeterministic finite automaton and prove that FO translations are precisely the mappings computed by single-valued aperiodic nondeterministic finite transducers.Comment: 10 pages, 1 figur

Well-Founded Semantics for Extended Datalog and Ontological Reasoning

The Datalog± family of expressive extensions of Datalog has recently been introduced as a new paradigm for query answering over ontologies, which captures and extends several common description logics. It extends plain Datalog by features such as existentially quantified rule heads and, at the same time, restricts the rule syntax so as to achieve decidability and tractability. In this paper, we continue the research on Datalog±. More precisely, we generalize the well-founded semantics (WFS), as the standard semantics for nonmonotonic normal programs in the database context, to Datalog± programs with negation under the unique name assumption (UNA). We prove that for guarded Datalog± with negation under the standard WFS, answering normal Boolean conjunctive queries is decidable, and we provide precise complexity results for this problem, namely, in particular, completeness for PTIME (resp., 2-EXPTIME) in the data (resp., combined) complexity