Driving steady-state visual evoked potentials at arbitrary frequencies using temporal interpolation of stimulus presentation

Date of Acceptance: 29/10/2015 We thank Renate Zahn for help with data collection. This work was supported by Deutsche Forschungsgemeinschaft (AN 841/1-1, MU 972/20-1). We would like to thank A. Trujillo-Ortiz, R. Hernandez-Walls, A. Castro-Perez and K. BarbaRojo (Universidad Autonoma de Baja California) for making Matlab code for non-sphericity corrections freely available.Peer reviewedPublisher PD

The Purpose of Remittances – Evidence from Germany

This paper examines the purpose of remittances using individual data of migrants in Germany. Particular attention is paid to migrants’ savings and transfers to family members in the home country. Our findings indicate that migrants who intend to stay in Germany only temporarily have a higher propensity to save and save larger amounts in their home country than permanent migrants. A similar picture emerges when considering migrants’ payments to family members abroad. The results of a decomposition analysis indicate that temporary and permanent migrants seem to have different preferences towards sending transfers abroad, while economic characteristics and the composition of households in home and host countries are less relevant.International migration, savings, remittances

Probing tails of energy distributions using importance-sampling in the disorder with a guiding function

We propose a simple and general procedure based on a recently introduced approach that uses an importance-sampling Monte Carlo algorithm in the disorder to probe to high precision the tails of ground-state energy distributions of disordered systems. Our approach requires an estimate of the ground-state energy distribution as a guiding function which can be obtained from simple-sampling simulations. In order to illustrate the algorithm, we compute the ground-state energy distribution of the Sherrington-Kirkpatrick mean-field Ising spin glass to eighteen orders of magnitude. We find that the ground-state energy distribution in the thermodynamic limit is well fitted by a modified Gumbel distribution as previously predicted, but with a value of the slope parameter m which is clearly larger than 6 and of the order 11.Comment: 7 pages, 5 figures, 3 table

Labor Market Effects of Immigration: Evidence from Neighborhood Data

This paper combines individual-level data from the German Socio-Economic Panel (SOEP) with economic and demographic postcode-level data from administrative records to analyze the effects of immigration on wages and unemployment probabilities of high- and low-skilled natives. Employing an instrumental variable strategy and utilizing the variation in the population share of foreigners across regions and time, we find no support for the hypothesis of adverse labor market effects of immigration.

Analyzing the Labor Market Activity of Immigrant Families in Germany

This paper analyzes whether immigrant families facing credit constraints adopt a family investment strategy wherein,upon arrival,an immigrant spouse invests in host country-specific human capital while the other partner works to finance the family’s current consumption. Using data for West Germany, we do not find evidence for such a specialization strategy.We further examine the labor supply and wage assimilation of families whose members immigrated together relative to families whose members immigrated sequentially. Our estimates indicate that this differentiation is relevant for the analysis of the labor market activities of migrant households.International migration, assimilation, family investment hypothesis

Overcoming system-size limitations in spin glasses

In order to overcome the limitations of small system sizes in spin-glass simulations, we investigate the one-dimensional Ising spin chain with power-law interactions. The model has the advantage over traditional higher-dimensional Hamiltonians in that a large range of system sizes can be studied. In addition, the universality class of the model can be changed by tuning the power law exponent, thus allowing us to scan from the mean-field to long-range and short-range universality classes. We illustrate the advantages of this model by studying the nature of the spin glass state where our results hint towards a replica symmetry breaking scenario. We also compute ground-state energy distributions and show that mean-field and non-mean-field models are intrinsically different.Comment: 5 pages, 2x2 figures, proceedings of the 2004 SPDSA Conference in Hayama, Japan, July 12 - 15, 200

Scaling graphs of heart rate time series in athletes demonstrate the VLF, LF and HF regions

Scaling analysis of heart rate time series has emerged as an useful tool for assessment of autonomic cardiac control. We investigate the heart rate time series of ten athletes (five males and five females), by applying detrended fluctuation analysis (DFA). High resolution ECGs are recorded under standardized resting conditions over 30 minutes and subsequently heart rate time series are extracted and artefacts filtered. We find three distinct regions of scale-invariance, which correspond to the well-known VLF, LF, and HF bands in the power spectra of heart rate variability. The scaling exponents alpha are alphaHF: 1.15 [0.96-1.22], alphaLF: 0.68 [0.57-0.84], alphaVLF: 0.83[0.82-0.99]; p<10^-5). In conclusion, DFA scaling exponents of heart rate time series should be fitted to the VLF, LF, and HF ranges, respectively

A Comparative Analysis of the Nativity Wealth Gap

This paper investigates the source of the gap in the relative wealth position of immigrant households residing in Australia, Germany and the United States. Our results indicate that in Germany and the United States wealth differentials are largely the result of disparity in the educational attainment and demographic composition of the native and immigrant populations, while income differentials are relatively unimportant in understanding the nativity wealth gap. In contrast, the relatively small wealth gap between Australian- and foreign- born households exists because immigrants to Australia do not translate their relative educational and demographic advantage into a wealth advantage. On balance, our results point to substantial cross-national disparity in the economic well-being of immigrant and native families, which is largely consistent with domestic labor markets and the selection policies used to shape the nature of the immigration flow.International migration, wealth accumulation

Recent advances in minimally invasive colorectal cancer surgery

Laparoscopy has improved surgical treatment of various diseases due to its limited surgical trauma and has developed as an interesting therapeutic alternative for the resection of colorectal cancer. Despite numerous clinical advantages (faster recovery, less pain, fewer wound and systemic complications, faster return to work) the laparoscopic approach to colorectal cancer therapy has also resulted in unusual complications, i.e. ureteral and bladder injury which are rarely observed with open laparotomy. Moreover, pneumothorax, cardiac arrhythmia, impaired venous return, venous thrombosis as well as peripheral nerve injury have been associated with the increased intraabdominal pressure as well as patient's positioning during surgery. Furthermore, undetected small bowel injury caused by the grasping or cauterizing instruments may occur with laparoscopic surgery. In contrast to procedures performed for nonmalignant conditions, the benefits of laparoscopic resection of colorectal cancer must be weighed against the potential for poorer long-term outcomes of cancer patients that still has not been completely ruled out. In laparoscopic colorectal cancer surgery, several important cancer control issues still are being evaluated, i.e. the extent of lymph node dissection, tumor implantation at port sites, adequacy of intraperitoneal staging as well as the distance between tumor site and resection margins. For the time being it can be assumed that there is no significant difference in lymph node harvest between laparoscopic and open colorectal cancer surgery if oncological principles of resection are followed. As far as the issue of port site recurrence is concerned, it appears to be less prevalent than first thought (range 0-2.5%), and the incidence apparently corresponds with wound recurrence rates observed after open procedures. Short-term (3-5 years) survival rates have been published by a number of investigators, and survival rates after laparoscopic surgery appears to compare well with data collected after conventional surgery for colorectal cancer. However, long-term results of prospective randomized trials are not available. The data published so far indicate that the oncological results of laparoscopic surgery compare well with the results of the conventional open approach. Nonetheless, the limited information available from prospective studies leads us to propose that minimally invasive surgery for colorectal cancer surgery should only be performed within prospective trials

Blinder-Oaxaca decomposition for Tobit models

In this paper, a decomposition method for Tobit-models is derived, which allows the differences in a censored outcome variable between two groups to be decomposed into a part that is explained by differences in observed characteristics and a part attributable to differences in the estimated coefficients. The method is applied to a decomposition of the gender wage gap using German data