Ordered increasing k-trees: Introduction and analysis of a preferential attachment network model

We introduce a random graph model based on k-trees, which can be generated by applying a probabilistic preferential attachment rule, but which also has a simple combinatorial description. We carry out a precise distributional analysis of important parameters for the network model such as the degree, the local clustering coefficient and the number of descendants of the nodes and root-to-node distances. We do not only obtain results for random nodes, but in particular we also get a precise description of the behaviour of parameters for the j-th inserted node in a random k-tree of size n, where j = j(n) might grow with n. The approach presented is not restricted to this specific k-tree model, but can also be applied to other evolving k-tree models.Comment: 12 pages, 2 figure

The impact of the provision of public infrastructures on regional economic development in Germany

The present paper presents an analysis of the impact of public infrastructure capital on regional economic developments in Germany. After presenting some descriptive statistical data on the economies of the 11 regions in (West) Germany a simple theoretical model of a cost-minimizing firm is presented in which the stock of public capital is included as a proxy for public services provided to firms as a fixed unpaid factor of production. Duality theory is used to recover the productivity effects of public infrastructures by calculating the cost-saving effects that are associated with public services. It is shown that these cost-saving effects work their way through adjustments in the demand for private inputs. Using a translog cost 'function we present panel estimates for the 11 federal states of (West) Germany with labour, structures and equipment as private factors of production. The results strongly indicate that public capital formation encourages private investment. In addition, it is demonstrated empirically that with respect to private capital a distinction between structures and equipment is of crucial importance because the effects on the former are of far greater importance than the effects on the latter. --

Regional productivity growth and investments in public infrastructure: the case of Germany

This paper examines whether the productivity growth in the West-German states is influenced by the provision of public infrastructure. Medium-term labour productivity growth and output growth varies a lot between German states. This differences are more pronounced during the eighties. The traditional total factor productivity shows a smaller difference than labour productivity. The regional differences in the productivity growth rates can only partly be attributed to the differences in factor input growth. We estimate a translog-cost-function for the period 1970-1988 for 11 German states using a three-equation fixed-effects panel data model. We show that there are important cost-saving effects that are associated with public services. Likewise, the demand for labour, and the private investment demand for structures and equipment is effected by public capital goods. Our estimates indicate that public capital formation encourages private investment. This effect is especially strong with respect to the private demand for structures. These results confirm that regional or urban economic growth can be forstered by the government by public investment. --

Die neue spanische Umgehungsvorschrift des Art. 15 Ley General Tributaria (LGT) – Ist der deutsche § 42 AO als Vorbild geeignet?

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Umschuldungsklauseln (Collective Action Clauses) in Staatsanleihen des europäischen Währungsraumes

Umschuldungsklauseln in Staatsanleihen führten in Europa bis zur Euro-Krise ein Schattendasein. In Deutschland waren sie weithin unbekannt. Der ESM-Vertrag hat dies geändert und diese Klauseln als zentrales Instrument zur rechtssicheren Umsetzung zukünftiger Restrukturierungen in den Fokus gerückt. Seit Jahresbeginn 2013 sind die „europäischen Umschuldungsklauseln“ in der Emissionspraxis der Euro-Staaten angekommen und fester Bestandteil der Anleihebedingungen. Georg Seitz untersucht Umschuldungsklauseln in der Euro-Zone sowohl auf konzeptioneller Ebene als Lösungsstrategie für die Problematik der Staateninsolvenz als auch kautelarjuristisch hinsichtlich der konkreten Ausgestaltung der Klauseln und berücksichtigt dabei alle berührten Rechtsgebiete. Der Autor arbeitet Genese, Funktionsweise und Zusammenspiel der europäischen Umschuldungsklauseln mit den übrigen Instrumenten des ESM heraus und systematisiert die europäischen Musterklauseln sowie deren Umsetzung in Deutschland. Dabei kritisiert er den auf europäischer Ebene gewählten informellen und dezentralen Ansatz und belegt dessen Schwächen anhand von Umsetzungsdefiziten bei den deutschen Klauseln. Als bisher unterschätzten Problemkreis identifiziert er den Rechtsschutz der überstimmten Gläubiger. Aufbauend auf die Ergebnisse seiner Analyse schlägt der Autor eine Verankerung der Umschuldungsklauseln im Recht der Europäischen Union in Form einer Verordnung vor und stellt dar, auf welche Weise ein solcher Ansatz gelingen kann

Modeling The Microrelief Structure of Ti6Al4V Titanium Alloy Surface After Exposure to Femtosecond Laser Pulses

A method of mathematical modeling of the ordered surface relief of titanium alloy Ti6Al4V after femtosecond laser treatment is proposed, which allowed obtaining the informative signs of the self-organized surface irregularities, taking into account the stochastic and cyclic nature of this process. An algorithm has been developed, and a package of computer programs has been created based on the proposed mathematical model. These methods make it possible to analyze the zone-spatial two-dimensional structure of the cyclic relief of the modified surface. They are also the basis for creating the specialized software for the automated profilometric diagnostic systems

Magnetic-activated cell sorting (MACS) can be used as a large-scale method for establishing zebrafish neuronal cell cultures

Neuronal cell cultures offer a crucial tool to mechanistically analyse regeneration in the nervous system. Despite the increasing importance of zebrafish (Danio rerio) as an in vivo model in neurobiological and biomedical research, in vitro approaches to the nervous system are lagging far behind and no method is currently available for establishing enriched neuronal cell cultures. Here we show that magnetic-activated cell sorting (MACS) can be used for the large-scale generation of neuronal-restricted progenitor (NRP) cultures from embryonic zebrafish. Our findings provide a simple and semi-automated method that is likely to boost the use of neuronal cell cultures as a tool for the mechanistic dissection of key processes in neuronal regeneration and development

Neural networks engaged in tactile object manipulation: patterns of expression among healthy individuals

<p>Abstract</p> <p>Background</p> <p>Somatosensory object discrimination has been shown to involve widespread cortical and subcortical structures in both cerebral hemispheres. In this study we aimed to identify the networks involved in tactile object manipulation by principal component analysis (PCA) of individual subjects. We expected to find more than one network.</p> <p>Methods</p> <p>Seven healthy right-handed male volunteers (aged 22 to 44 yrs) manipulated with their right hand aluminium spheres during 5 s with a repetition frequency of 0.5-0.7 Hz. The correlation coefficients between the principal component temporal expression coefficients and the hemodynamic response modelled by SPM (ecc) determined the task-related components. To establish reproducibility within subjects and similarity of functional connectivity patterns among subjects, regional correlation coefficients (rcc) were computed between task-related component image volumes. By hierarchically categorizing, selecting and averaging the task-related component image volumes across subjects according to the rccs, mean component images (MCIs) were derived describing neural networks associated with tactile object manipulation.</p> <p>Results</p> <p>Two independent mean component images emerged. Each included the primary sensorimotor cortex contralateral to the manipulating hand. The region extended to the premotor cortex in MCI 1, whereas it was restricted to the hand area of the primary sensorimotor cortex in MCI 2. MCI 1 showed bilateral involvement of the paralimbic anterior cingulate cortex (ACC), whereas MCI 2 implicated the midline thalamic nuclei and two areas of the rostral dorsal pons.</p> <p>Conclusions</p> <p>Two distinct networks participate in tactile object manipulation as revealed by the intra- and interindividual comparison of individual scans. Both were employed by most subjects, suggesting that both are involved in normal somatosensory object discrimination.</p

Early evaluation of corneal collagen crosslinking in ex-vivo human corneas using two-photon imaging

The clinical outcome of corneal collagen crosslinking (CXL) is typically evaluated several weeks after treatment. An earlier assessment of its outcome could lead to an optimization of the treatment, including an immediate re-intervention in case of failure, thereby, avoiding additional discomfort and pain to the patient. In this study, we propose two-photon imaging (TPI) as an earlier evaluation method. CXL was performed in human corneas by application of riboflavin followed by UVA irradiation. Autofluorescence (AF) intensity and lifetime images were acquired using a commercial clinically certified multiphoton tomograph prior to CXL and after 2h, 24h, 72h, and 144h storage in culture medium. The first monitoring point was determined as the minimum time required for riboflavin clearance from the cornea. As control, untreated samples and samples treated only with riboflavin (without UVA irradiation) were monitored at the same time points. Significant increases in the stroma AF intensity and lifetime were observed as soon as 2h after treatment. A depth-dependent TPI analysis showed higher AF lifetimes anteriorly corresponding to areas were CXL was most effective. No alterations were observed in the control groups. Using TPI, the outcome of CXL can be assessed non-invasively and label-free much sooner than with conventional clinical devices.European Union Horizon 2020 (LASER-HISTO); European project FLIMVERTIC