Size and Orientation of the `Z' in ZRGs

Some X-shaped radio galaxies (XRGs) show a Z-symmetric morphology in the less luminous secondary lobes. Our geometrical arguments strongly support a merger of two galaxies as mechanism for the formation of these sources (ZRG). They also strengthen the conjecture that a jet is aligned with the spin of the BH at its base and that the jet flips into the direction of the orbital angular momentum of the pre-merger binary black hole (BHB). We could also restrict the distance where the pre-merger jet is bent into Z-shape by the inspiralling galaxy to the range of 30-100 kpc. One of three possible orientations of the jet relative to our line of sight is more likely than the others and allows us to deduce the direction of the spin of the merged BH. The existence of XRGs and ZRGs proves that the binary has merged, contrary to previous speculations that after a merger of two galaxies the decay of the BHB stalls due to loss cone depletion. In ZRGs the black holes probably merge on timescales of some 10^8 yr after the bending of the jet in a distance of about 50 kpc. Thus, in a way, the bending starts a stop watch for the rest of the merger.Comment: 2 pages, to appear in the proceedings of ESO Astrophysics Symposia: Groups of Galaxies in the Nearby Universe, Santiago de Chile, Dec. 200

Regional employment impacts of Common Agricultural Policy measures in Eastern Germany: A difference-in-differences approach

Politicians and farm lobbyists frequently use the argument that agricultural policy is necessary to safeguard jobs in agriculture. We explore whether this is true by conducting an econometric ex-post evaluation of the European Union’s Common Agricultural Policy (CAP) in the three East German States Brandenburg, Saxony, and Saxony-Anhalt. Whereas previous studies have employed descriptive statistics or qualitative methods and have looked at single policy instruments in isolation, we apply a difference-in-differences estimator to analyse the employment effects of the entire portfolio of CAP measures simultaneously. Based on panel data at the county level, we find that investment aids and transfers to less favoured areas had a zero marginal employment effect. We present evidence that full decoupling of direct payments in 2005 led to labour shedding, as it made transfer payments independent of factor allocation. Spending on modern technologies in processing and marketing and measures aimed at the development of rural areas led to job losses in agriculture. Agri-environmental measures, on the other hand, kept labour intensive technologies in production or induced them. This analysis calls into question whether an expansion of existing second pillar measures is a reasonable way to use funds modulated away from the first pillar.Impact analysis, Agricultural employment, Common Agricultural Policy, Decoupling, Agribusiness, Agricultural and Food Policy, Agricultural Finance, Community/Rural/Urban Development, Labor and Human Capital, Q18, J43, R58,

CAP REFORM AND THE EFFECTS OF DIRECT PAYMENTS ON HETEROGENEOUS FARM STRUCTURES IN EAST GERMANY

Structural change, Dynamic panel data models, Common Agricultural Policy, East Germany, Agricultural and Food Policy, Farm Management, Research Methods/ Statistical Methods,

Factors Affecting Retention of Transfer Students at Linfield College

Building on the work of Tyler (2011), this paper analyzes the factors that affect the decision by transfer students at Linfield College to return for a second year. Data was obtained for transfer students from the Department of Institutional Research at Linfield College from 2009 to 2013. We estimate the logit probabilities of retention likelihood as a function of academic ability, net price, curricular engagement, extra-curricular engagement, choice of major and demographic characteristics. We find that academic ability, curricular engagement, institutional commitment, and choice of major variables may be significant factors in the retention of transfer students at Linfield College. The estimated effects and the resulting conclusions must be interpreted cautiously due to our small sample size. However, a discussion of the results shows that Linfield may be able to improve retention of transfer students through increased curricular engagement and greater departmental awareness

Direct Payments, Farm Survival, and Strategic Farm Creation: The Case of Large-Scale Agricultural Structures in East Germany

Agricultural and Food Policy, Farm Management,

CAP IMPACTS ON LABOUR USE IN EAST GERMAN AGRICULTURE

Agricultural employment, Dynamic panel data models, Common Agricultural Policy, East Germany, Agricultural and Food Policy, Community/Rural/Urban Development, Research Methods/ Statistical Methods, Q18, J43, C23,

“Champion Man-Hater of All Time”: Feminism, Insanity, and Property Rights in 1940s America

Legions of law students in property or trusts and estates courses have studied the will dispute, In re Strittmater’s Estate. The cases, casebooks, and treatises that cite Strittmater present the 1947 decision from New Jersey’s highest court as a model of the “insane delusion” doctrine. Readers learn that snubbed relatives successfully invalidated Louisa Strittmater’s will, which left her estate to the Equal Rights Amendment campaign, by convincing the court that her radical views on gender equality amounted to insanity and, thus, testamentary incapacity. By failing to provide any commentary or context on this overt sexism, these sources affirm the court’s portrait of Louisa Strittmater as an eccentric landlady and fanatical feminist. This is troubling. Strittmater should be a well-known case, but not for the proposition that feminism is an insane delusion. Despite the decision’s popularity on law school syllabi, no scholar has interrogated the case’s broader historical background. Through original archival research, this Article centers Strittmater as a case study in how social views on gender, psychology, and the law shaped one another in the immediate aftermath of World War II, hampering women’s property rights and efforts to achieve constitutional equality. More than just a problematic precedent, the case exposes a world in which the “Champion Man-Hater of All Time”—newspapers’ epithet for Strittmater—was not only a humorous headline but also a credible threat to the postwar order that courts were helping to erect. The Article thus challenges the textbook understanding of “insane delusion” and shows that postwar culture was conducive to a strengthening of the longstanding suspicion that feminist critiques of gender inequality were, simply put, crazy

Lessons for the Philanthropic Sector on the Use of Matching Contingencies

Many philanthropic institutions require prospective or current grantees to match all or part of the value of a grant in order to secure funding. Foundations use matching contingencies to recruit funding partners, build grantee capacity to raise funds, replicate program models, and exit from the field, among other purposes. In January 2014, Atlantic commissioned Mathematica Policy Research to evaluate its matching practices. The purpose of the evaluation is to document the utility and outcomes of Atlantic's use of matching requirements. The findings in this report provide information on the outcomes and effects of the use of matching contingencies to inform other philanthropic organizations about possible consequences of this funding practice

Taming rotationally supported disks using state of the art numerical methods

Während des gravitativen Kollapses eines Objekts bleibt der Drehimpuls erhalten. Im Fall eines endlichen Drehimpulses im System kann sich eine rotierende Scheibe bilden, die durch die Rotation stabilisiert wird. Aufgrund der Einfachheit dieses Mechanismus sind Scheiben allgegenwärtig in der Astrophysik, beispielsweise als protoplanetare Scheiben, Akkretionsscheiben um Schwarze Löcher oder Spiralgalaxien. Insbesondere kalte Gasscheiben sind allerdings schwierig numerisch zu simulieren, da die Rotationsgeschwindigkeit deutlich über der Schallgeschwindigkeit liegt und bereits geringe Ungenauigkeiten in der verwendeten numerischen Methode zu einem unphysikalischem Wachstum von Fluidinstabilitäten führen können. Dies ist besonders dann problematisch, wenn man echte, physikalische Instabilitäten in diesen Systemen analysieren möchte. Eine Methode, die im Prinzip besonders geeignet für die Analyse von Scheibensystemen sein sollte, ist die Berechnung der magnetohydrodynamischen Gleichungen auf einem mitbewegten Gitter, wie sie in dem kosmologischen Code AREPO realisiert ist. Hierdurch kann die Überschallströmung des Gases aufgrund der Rotationsgeschwindigkeit in die Bewegung des Gitters aufgenommen und dadurch eliminiert werden. Die Bewegung und permanente Verzerrung der Gitterzellen aufgrund differentieller Rotation führt jedoch in der ursprünglichen Version von AREPO zu numerischem Rauschen, was die Nützlichkeit des Codes für kalte Scheiben deutlich reduziert hat. Das Ziel dieser Arbeit war es zunächst, die Ursache des Rauschens zu ermitteln und zu beheben. Anschließend sollte evaluiert werden, wie gut die verbesserte Methode kalte Scheiben beschreiben kann, insbesondere in Situationen, in denen Turbulenz durch Magnetfelder oder durch die Wechselwirkung von Strahlungskühlung und Gravitation erzeugt wird. Im Rahmen dieser Arbeit habe ich zuerst die sogenannte "Shearing-Box" Näherung in AREPO entwickelt, die es ermöglicht, einen kleinen Teil einer rotierenden Scheibe mit sehr hoher Auflösung zu simulieren. Im Gegensatz zu Implementierungen in anderen Codes bietet meine Lösung eine adaptive Gitterauflösung sowie vollständige Translationinvarianz. Daneben konnte ich durch eine präzisere numerische Integration der Flussfunktion über die Grenzflächen aneinanderstoßender Zellen das Rauschen auf Zellebene beheben und damit die Genauigkeit des Codes für Scherströmungen stark erhöhen. Auf Basis dieser Verbesserungen habe ich anschließend die magnetische Rotationsinstabilität (MRI) in der Shearing-Box und die dabei auftretenden magnetischen Dynamo-Effekte analysiert. Sowohl im linearen als auch im nichtlinearen Bereich habe ich gute Übereinstimmung mit früheren Ergebnissen in der Literatur gefunden, die mit statischen Gittercodes erzielt wurden. In einer weiteren Studie habe ich eine Codeerweiterung entwickelt, welche die Gravitationskräfte zwischen Massenelementen innerhalb der Simulationsregion unter Einbeziehung der speziellen Randbedingungen der Shearing-Box und ohne Auflösungsbeschränkungen berechnen kann. Mit Hilfe des sogenannten beta-Kühlens konnte ich zeigen, dass bei schwachem Strahlungskühlen unter Eigengravitation und Scherung ein gravitoturbulenter Zustand entsteht, während sich bei effizienterem Kühlen Fragmente aus kollabierenden Gaswolken herausbilden können. Schließlich habe ich die sogenannte Rossby-Wellen-Instabilität in globalen, zweidimensionalen Scheibensimulationen analysiert. Hierbei konnte ich sowohl im linearen als auch im nichtlinearen Bereich gute Übereinstimmung mit der Literatur erzielen. Die Entwicklung der Shearing-Box-Näherung und die Beseitigung des Rauschens auf Gitterebene in dem Verfahren mit einem bewegten Gitter ermöglicht vielfältige Forschungsanwendungen in der Zukunft. Einerseits kann die Wechselwirkung verschiedener Instabilitäten in Scheiben mit Hilfe der Shearing-Box präzise analysiert werden, andererseits sind nun auch globale Simulationen von ganzen Scheiben mit der Methode des bewegten Gitters möglich. Dieses Verfahren ermöglicht wesentlich größere Zeitschritte und geringere Advektionsfehler als herkömmliche Methoden mit stationären Gittern. Auch können Teile einer galaktischen Scheibe mit meiner Shearing-Box Methode in einem "Zoom" Modus simuliert werden, wobei insbesondere die geometrisch flexible, adaptive Auflösung der Methode von Vorteil ist.During the gravitational collapse of an object, the angular momentum is conserved. In the case of a finite angular momentum in the system, a rotating disk can form, stabilized by the rotation. Due to the simplicity of this mechanism, disks are ubiquitous in astrophysics, with prominent examples being protoplanetary disks, accretion disks around black holes, or spiral galaxies. However, cold gas disks in particular are difficult to be simulated numerically because the rotational velocity is much larger than the speed of sound and even small inaccuracies in the used numerical method can lead to the unphysical growth of fluid instabilities. This is particularly problematic when one tries to analyze real, physical instabilities in these systems. A method that in principle should be particularly suitable for the analysis of disk systems is the solution of the magnetohydrodynamic equations on a moving mesh, as realized in the cosmological code AREPO. This allows the supersonic flow of the gas due to the rotational velocity to be included in the mesh motion and thereby to be eliminated. However, the motion and constant distortion of the grid cells due to differential rotation introduce numerical noise in the original version of AREPO, which has significantly reduced the usefulness of the code for cold disks. The goal of this work was first to identify and remove the origin of this "grid noise'', and second to evaluate how well the improved method can describe cold disks, especially in situations where turbulence is generated by magnetic fields or by the interaction of radiative cooling and gravity. As part of this thesis, I first implemented the so-called "shearing-box'' approximation in AREPO, which allows a small portion of a rotating disk to be simulated at very high resolution. Unlike implementations in other codes, my solution provides an adaptive spatial resolution as well as full translation invariance. Additionally, by integrating the flux function more precisely over the interfaces of neighbouring cells, I was able to remove the grid noise, greatly increasing the accuracy of the code for shear flows. Based on these improvements, I analyzed the magnetorotational instability (MRI) in the shearing box and the magnetic dynamo effects that one can observe. In both the linear and nonlinear regimes, I found good agreement with previous results in the literature obtained with static grid codes. In a further line of work, I have developed a code extension that can compute gravitational forces between mass elements within the simulation box, including the special boundary conditions of the shearing box and without resolution constraints. Using the so-called beta-cooling, I was able to show that weak radiative cooling in combination with self-gravity and shear can produce a gravito-turbulent state, while more efficient cooling can produce fragments in the form of collapsing gas clouds. Finally, I analyzed the so-called Rossby wave instability in global, two-dimensional disk simulations. Here I was able to obtain good agreement with the literature in both the linear and nonlinear regimes. The development of the shearing-box approximation and the elimination of the grid noise in the moving mesh method allows a variety of research applications in the future. On the one hand, the interaction of different fluid instabilities in disks can be precisely analyzed using the shearing box, and on the other hand, global simulations of entire disks are now possible using the moving mesh method. This approach allows much larger time steps and smaller advection errors than conventional methods with stationary grids. Also, parts of a galactic disk can be simulated with my shearing box method in a ``zoom'' mode, where the geometrically flexible, adaptive resolution of the method is a particular advantage