The Economic Impact of Social Ties: Evidence from German Reunification

We use the fall of the Berlin Wall in 1989 to show that personal relationships which individuals maintain for non-economic reasons can be an important determinant of regional economic growth. We show that West German households who have social ties to East Germany in 1989 experience a persistent rise in their personal incomes after the fall of the Berlin Wall. Moreover, the presence of these households significantly affects economic performance at the regional level: it increases the returns to entrepreneurial activity, the share of households who become entrepreneurs, and the likelihood that firms based within a given West German region invest in East Germany. As a result, West German regions which (for idiosyncratic reasons) have a high concentration of households with social ties to the East exhibit substantially higher growth in income per capita in the early 1990s. A one standard deviation rise in the share of households with social ties to East Germany in 1989 is associated with a 4.6 percentage point rise in income per capita over six years. We interpret our findings as evidence of a causal link between social ties and regional economic development.economic development, German reuni cation, networks, social ties

Weak Alfvén-wave turbulence revisited

Weak Alfvénic turbulence in a periodic domain is considered as a mixed state of Alfvén waves interacting with the two-dimensional (2D) condensate. Unlike in standard treatments, no spectral continuity between the two is assumed, and, indeed, none is found. If the 2D modes are not directly forced, k−2 and k−1 spectra are found for the Alfvén waves and the 2D modes, respectively, with the latter less energetic than the former. The wave number at which their energies become comparable marks the transition to strong turbulence. For imbalanced energy injection, the spectra are similar, and the Elsasser ratio scales as the ratio of the energy fluxes in the counterpropagating Alfvén waves. If the 2D modes are forced, a 2D inverse cascade dominates the dynamics at the largest scales, but at small enough scales, the same weak and then strong regimes as described above are achieved

The Impact of Stealthy Attacks on Smart Grid Performance: Tradeoffs and Implications

The smart grid is envisioned to significantly enhance the efficiency of energy consumption, by utilizing two-way communication channels between consumers and operators. For example, operators can opportunistically leverage the delay tolerance of energy demands in order to balance the energy load over time, and hence, reduce the total operational cost. This opportunity, however, comes with security threats, as the grid becomes more vulnerable to cyber-attacks. In this paper, we study the impact of such malicious cyber-attacks on the energy efficiency of the grid in a simplified setup. More precisely, we consider a simple model where the energy demands of the smart grid consumers are intercepted and altered by an active attacker before they arrive at the operator, who is equipped with limited intrusion detection capabilities. We formulate the resulting optimization problems faced by the operator and the attacker and propose several scheduling and attack strategies for both parties. Interestingly, our results show that, as opposed to facilitating cost reduction in the smart grid, increasing the delay tolerance of the energy demands potentially allows the attacker to force increased costs on the system. This highlights the need for carefully constructed and robust intrusion detection mechanisms at the operator.Comment: Technical report - this work was accepted to IEEE Transactions on Control of Network Systems, 2016. arXiv admin note: substantial text overlap with arXiv:1209.176

Revisiting the Comfort Parameters of ISO 7730: Measurement and Simulation

With the trends of comfort modelling moving more towards the application of Adaptive Models, the influences of several parameters as used in the traditional ISO7730 standard are therefore non-existent. The proposed work considers the conventional ISO 7730 standard as conservative in its calculation; however extremely useful, in cases where actual measurements of spaces are considered (ISO 7730, 1994). Measurements from a comfort cart built according to ASHRAE-55 standards (ANSI/ASHRAE 55, 2005) together with thermal imaging temperatures are combined. In doing so, an ISO 7730 thermal comfort assessment applying the CBE – ASHRAE 55-2004 Comfort Tool allows for changes in the environment to be examined for improved comfort (Huizenga, 2006; Tyler et al, 2017). Results for two cases in a severe Darwin climate yield an improved PPD by 2.5-2.7 times when implementing extremely low- energy measures

The Economic Impact of Social Ties: Evidence from German Reunification

We use the fall of the Berlin Wall in 1989 to show that personal relationships which individuals maintain for non-economic reasons can be an important determinant of regional economic growth. We show that West German households who have social ties to East Germany in 1989 experience a persistent rise in their personal incomes after the fall of the Berlin Wall. Moreover, the presence of these households significantly affects economic performance at the regional level: it increases the returns to entrepreneurial activity, the share of households who become entrepreneurs, and the likelihood that firms based within a given West German region invest in East Germany. As a result, West German regions which (for idiosyncratic reasons) have a high concentration of households with social ties to the East exhibit substantially higher growth in income per capita in the early 1990s. A one standard deviation rise in the share of households with social ties to East Germany in 1989 is associated with a 4.6 percentage point rise in income per capita over six years. We interpret our findings as evidence of a causal link between social ties and regional economic development.

The role of lipids in drug absorption throught the GIT

Os vectores lipídicos apresentam inúmeras vantagens para a administração oral de substâncias farmacológicas, p.ex. são compostos por moléculas lipídicas semelhantes àquelas que figuram nos tecidos humanos, tornando-se biocompatíveis, biotoleráveis e biodegradáveis. São exemplos as tradicionais emulsões O/A, as suspensões de nanopartículas lipídicas (SLNs e NLC s) e, recentemente, as SolEmuls®, que permitem localizar fármacos fracamente solúveis em ambas as fases das emulsões, na camada interfacial de lecitina. Este artigo aborda o papel dos lípidos no aumento da absorção e da biodisponibilidade de fármacos administrados oralmente. Lipid carriers show several advantages for oral delivery of pharmacologically active drugs, e.g. are composed of lipid molecules similar to those in human tissues, becoming therefore biocompatible, biotolerable and biodegradable. Examples include traditional o/w emulsions, suspensions of lipid nanoparticles (SLNs and NLC s) and, recently, the SolEmuls®, which allows localizing poorly soluble drug molecules both in oil and aqueous phases, in the interfacial layer of lecithin. This paper reports on the role of lipids in enhancing both drug absorption and bioavailability when administered orally

Conceptual Clustering in Database Systems

Classes are an integral part of all semantic data models. Despite this, class formation in these data models is ad hoc due to the varied treatment of classes and because the issue of grouping instances into classes is considered an art rather than a science. It is the view of this paper that class formation be based on category theory through the use of an aJtribute-based purpose-dieected conceptual clustering technique. Several issues concerned with category theory, especially exception handling, are discussed. The emphasis in this approach is on reasoning at the instance level. Schema generation occurs as a result of conceptually clustering the underlying data instances and guiding this process by specifying a context in the form of a clustering seed. The use of this approach in the areas of schema integration, schema evolution and querying will be discussed. These facilities have been implemented on a database system based on the CANDIDE [3] semantic data model. CANDIDE is essentially an extended version of the tenn-subsumption languages known as the KL-ONE family of languages