30 research outputs found
Early foreign investment into West Germany after the Second World War
The resumption of foreign investment across Western Europe after the end of the Second World War has so far received little attention in the literature on the post-war European economy. This dissertation studies the important case of foreign investment into West Germany during the early 1950s. Prior to the lifting of the Allied investment embargo in mid-1950, Germany had been isolated from international capital markets for almost two decades, and exchange controls were to remain in place for several more years to come. Under these circumstances, foreign investment was largely restricted to the reinvestment of foreign-owned blocked accounts held at German banks, commonly known as Sperrmark. Chapter One traces the history of Sperrmark and analyses their role as an early post-war, international medium of exchange. On the basis of this historical account, Chapter Two explores the universe of foreign direct investment projects between mid-1950 and early 1955 retrieved from archival sources. The high persistence of investment patterns across the preceding crisis period of the 1930s and the Second World War constitutes the most important finding of this paper: Investors who had already been active in Germany before the War also represented the most prominent group of post-war investors. Moreover, their established presence exerted significant influence on the investment decisions of new post-war entrants. These results are robust to taking into account a range of confounding influences and alternative explanations. Finally, Chapter Three studies the role of the London Debt Agreement of 1953 for contemporaneous foreign investment into West Germany. The settlement of Germanyâs outstanding external debt was a necessary condition for restoring the countryâs creditworthiness on international capital markets. However, outstanding pre-war indebtedness did not influence post-war foreign investment decisions on a micro-economic level, thus warranting a cautious view on the effects of the Debt Agreement for the West German economy of the time
Efficient Branch-and-Bound Algorithms for Finding Triangle-Constrained 2-Clubs
In the Vertex Triangle 2-Club problem, we are given an undirected graph
and aim to find a maximum-vertex subgraph of that has diameter at most 2
and in which every vertex is contained in at least triangles in the
subgraph. So far, the only algorithm for solving Vertex Triangle 2-Club relies
on an ILP formulation [Almeida and Br\'as, Comput. Oper. Res. 2019]. In this
work, we develop a combinatorial branch-and-bound algorithm that, coupled with
a set of data reduction rules, outperforms the existing implementation and is
able to find optimal solutions on sparse real-world graphs with more than
100,000 vertices in a few minutes. We also extend our algorithm to the Edge
Triangle 2-Club problem where the triangle constraint is imposed on all edges
of the subgraph
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Supercritical fluid extraction-supercritical fluid chromatography of saliva: Single-quadrupole mass spectrometry monitoring of caffeine for gastric emptying studiesâ
Saliva is an attractive sampling matrix for measuring various endogenous and exogeneous substances but requires sample treatment prior to chromatographic analysis. Exploiting supercritical CO2 for both extraction and chromatography simplifies sample preparation, reduces organic solvent consumption, and minimizes exposure to potentially infectious samples, but has not yet been applied to oral fluid. Here, we demonstrate the feasibility and benefits of online supercritical fluid extraction coupled to supercritical fluid chromatography and single-quadrupole mass spectrometry for monitoring the model salivary tracer caffeine. A comparison of 13C- and 32S-labeled internal standards with external standard calibration confirmed the superiority of stable isotope-labeled caffeine over nonanalogous internal standards. As proof of concept, the validated method was applied to saliva from a magnetic resonance imaging study of gastric emptying. After administration of 35 mg caffeine via ice capsule, salivary levels correlated with magnetic resonance imaging data, corroborating caffeine's usefulness as tracer of gastric emptying (R2 = 0.945). In contrast to off-line methods, online quantification required only minute amounts of organic solvents and a single manual operation prior to online bioanalysis of saliva, thus demonstrating the usefulness of CO2-based extraction and separation techniques for potentially infective biomatrices
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Supercritical fluid extractionâsupercritical fluid chromatography of saliva: Singleâquadrupole mass spectrometry monitoring of caffeine for gastric emptying studies â
Abstract Saliva is an attractive sampling matrix for measuring various endogenous and exogeneous substances but requires sample treatment prior to chromatographic analysis. Exploiting supercritical CO 2 for both extraction and chromatography simplifies sample preparation, reduces organic solvent consumption, and minimizes exposure to potentially infectious samples, but has not yet been applied to oral fluid. Here, we demonstrate the feasibility and benefits of online supercritical fluid extraction coupled to supercritical fluid chromatography and singleâquadrupole mass spectrometry for monitoring the model salivary tracer caffeine. A comparison of 13 Câ and 32 Sâlabeled internal standards with external standard calibration confirmed the superiority of stable isotopeâlabeled caffeine over nonanalogous internal standards. As proof of concept, the validated method was applied to saliva from a magnetic resonance imaging study of gastric emptying. After administration of 35 mg caffeine via ice capsule, salivary levels correlated with magnetic resonance imaging data, corroborating caffeine's usefulness as tracer of gastric emptying ( R 2 = 0.945). In contrast to offâline methods, online quantification required only minute amounts of organic solvents and a single manual operation prior to online bioanalysis of saliva, thus demonstrating the usefulness of CO 2 âbased extraction and separation techniques for potentially infective biomatrices
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Saturation of the anomalous Hall effect at high magnetic fields in altermagnetic RuO2
Observations of the anomalous Hall effect in RuO2 and MnTe have demonstrated unconventional time-reversal symmetry breaking in the electronic structure of a recently identified new class of compensated collinear magnets, dubbed altermagnets. While in MnTe, the unconventional anomalous Hall signal accompanied by a vanishing magnetization is observable at remanence, the anomalous Hall effect in RuO2 is excluded by symmetry for the NĂ©el vector pointing along the zero-field [001] easy-axis. Guided by a symmetry analysis and ab initio calculations, a field-induced reorientation of the NĂ©el vector from the easy-axis toward the [110] hard-axis was used to demonstrate the anomalous Hall signal in this altermagnet. We confirm the existence of an anomalous Hall effect in our RuO2 thin-film samples, whose set of magnetic and magneto-transport characteristics is consistent with the earlier report. By performing our measurements at extreme magnetic fields up to 68 T, we reach saturation of the anomalous Hall signal at a field Hc â 55 T that was inaccessible in earlier studies but is consistent with the expected NĂ©el-vector reorientation field
Saturation of the anomalous Hall effect at high magnetic fields in altermagnetic RuO2
Observations of the anomalous Hall effect in RuO and MnTe have
demonstrated unconventional time-reversal symmetry breaking in the electronic
structure of a recently identified new class of compensated collinear magnets,
dubbed altermagnets. While in MnTe the unconventional anomalous Hall signal
accompanied by a vanishing magnetization is observable at remanence, the
anomalous Hall effect in RuO is excluded by symmetry for the N\'eel vector
pointing along the zero-field [001] easy-axis. Guided by a symmetry analysis
and ab initio calculations, a field-induced reorientation of the N\'eel vector
from the easy-axis towards the [110] hard-axis was used to demonstrate the
anomalous Hall signal in this altermagnet. We confirm the existence of an
anomalous Hall effect in our RuO thin-film samples whose set of magnetic
and magneto-transport characteristics is consistent with the earlier report. By
performing our measurements at extreme magnetic fields up to 68 T, we reach
saturation of the anomalous Hall signal at a field 55 T that
was inaccessible in earlier studies, but is consistent with the expected
N\'eel-vector reorientation field.Comment: 4 figure
Saturation of the anomalous Hall effect at high magnetic fields in altermagnetic RuO2
Observations of the anomalous Hall effect in RuO2 and MnTe have demonstrated unconventional time-reversal symmetry breaking in the electronic structure of a recently identified new class of compensated collinear magnets, dubbed altermagnets. While in MnTe, the unconventional anomalous Hall signal accompanied by a vanishing magnetization is observable at remanence, the anomalous Hall effect in RuO2 is excluded by symmetry for the NĂ©el vector pointing along the zero-field [001] easy-axis. Guided by a symmetry analysis and ab initio calculations, a field-induced reorientation of the NĂ©el vector from the easy-axis toward the [110] hard-axis was used to demonstrate the anomalous Hall signal in this altermagnet. We confirm the existence of an anomalous Hall effect in our RuO2 thin-film samples, whose set of magnetic and magneto-transport characteristics is consistent with the earlier report. By performing our measurements at extreme magnetic fields up to 68 T, we reach saturation of the anomalous Hall signal at a field Hc â 55 T that was inaccessible in earlier studies but is consistent with the expected NĂ©el-vector reorientation field