Star Vars: Finding the optimal Value-at-Risk approach for the banking industry

This paper explores the concept of Value-at-Risk (VaR) through a comparative study of nonparametric and parametric models in order to find the best risk model for banks’ trading portfolios. The non-parametric methods consist of three different approaches: Simple Historical Simulation, Age Weighted Historical Simulation and Volatility Weighted Historical Simulation by means of the EWMA and GARCH models for forecasting volatility. The parametric methods comprise six different approaches: VaR based on the normal distribution, VaR with Student’s t-distribution, RiskMetrics, VaR with implied volatility and VaR with GARCH volatility dynamics (both assuming normality and t-distribution). The models are estimated and tested on the S&P500 and a hypothetical bank trading portfolio. The evaluation of the models follows the Christoffersen framework of testing for correct conditional coverage together with assessment of model performance according to the regulatory requirements of the Basel Accord. The general finding is that models with leptokurtic features and time-varying volatility perform the best, while naïve models assuming normality and/or without volatility dynamics in general display poor performance. The GARCH(1,1)-t model by far outperforms its competitors as it can correctly account for both correct unconditional coverage and volatility clustering. The implications of market risk regulation are explored and it is argued that the current regulatory environment might provide incentives for low-quality risk management practices with significant room for regulatory improvements

Symbolic Behavior in Regular Classrooms: A Specification of Symbolic and Non-Symbolic Behavior

Students’ capabilities to use symbolic information in classroom setting could be expected to influence their possibilities to be active and participating. The development of strategies for teachers to compensate for reduced capability need specific operational definition of symbolic behavior. Fifty-three students, aged 11–13 years old, 29 boys and 24 girls, from three classes in the same Swedish compulsory regular school participated in the current study. After a short training sequence 25 students (47%) were defined as showing symbolic behavior (symbolic), and 28 students (53%) were not (non-symbolic), based on their follow-up test performances. Symbolic and non-symbolic differed significantly on post-test performances (p < 0.05). Surprisingly, non-symbolic behavior deteriorated their performance, while symbolic enhanced their performance (p < 0.05). The results indicate that the operational definition used in the present study may be useful in further studies relating the capability to show symbolic behavior and students’ activity and participation in classroom settings

The Other Side Now: What Blanding Prisoners of War Told the Wehrmacht

Fifty years after the arrival of German prisoners of war in Florida their story is still little known.1 Admittedly their presence was minimal since only about 4,000 out of the 378,000 German prisoners who spent time in America were detained in the state. Florida was one of forty-five states with POWs, and the base camp at Camp Blanding, with its fifteen side camps, was only one of 155 base camps in the continental United States

Cardiopulmonary Response to Exercise Testing in People with Chronic Stroke: A Retrospective Study

Background and Purpose. This study investigated the cardiopulmonary response and safety of exercise testing at peak effort in people during the chronic stage of stroke recovery. Methods. This retrospective study examined data from 62 individuals with chronic stroke (males: 32; mean (SD); age: (12.0) yr) participating in an exercise test. Results. Both males and females had low cardiorespiratory fitness levels. No significant differences were found between gender for peak HR (P = 0.27), or VO2 peak (P = 0.29). Males demonstrated higher values for minute ventilation, tidal volume, and respiratory exchange ratio. No major adverse events were observed in the exercise tests conducted. Discussion and Conclusion. There are differences between gender that may play a role in exercise testing performance and should be considered when developing exercise programs. The low VO2 peak of this cohort of chronic stroke survivors suggests the need for participation in exercise interventions

SCoT: a Python toolbox for EEG source connectivity

Analysis of brain connectivity has become an important research tool in neuroscience. Connectivity can be estimated between cortical sources reconstructed from the electroencephalogram (EEG). Such analysis often relies on trial averaging to obtain reliable results. However, some applications such as brain-computer interfaces (BCIs) require single-trial estimation methods. In this paper, we present SCoT—a source connectivity toolbox for Python. This toolbox implements routines for blind source decomposition and connectivity estimation with the MVARICA approach. Additionally, a novel extension called CSPVARICA is available for labeled data. SCoT estimates connectivity from various spectral measures relying on vector autoregressive (VAR) models. Optionally, these VAR models can be regularized to facilitate ill posed applications such as single-trial fitting. We demonstrate basic usage of SCoT on motor imagery (MI) data. Furthermore, we show simulation results of utilizing SCoT for feature extraction in a BCI application. These results indicate that CSPVARICA and correct regularization can significantly improve MI classification. While SCoT was mainly designed for application in BCIs, it contains useful tools for other areas of neuroscience. SCoT is a software package that (1) brings combined source decomposition and connectivtiy estimation to the open Python platform, and (2) offers tools for single-trial connectivity estimation. The source code is released under the MIT license and is available online at github.com/SCoT-dev/SCoT

Jiný pohled na etnicitu jako na biologický koncept: Posun antropolgie za koncept rasy

Montagu psal o rase jako o „nejnebezpečnějším lidském mýtu“ a Lévi-Strauss ji nazval „prvotním hříchem antropologie“. Přestože po celé 20. století vznikaly nové a nové přesvědčivé argumenty, proč by měl být koncept rasy opuštěn, pro antropology, kteří se zabývají klasifikací lidských populací, zůstává rasa významným problémem. Rasová terminologie se stala trvalým průvodcem antropologických počinů, což lze přičíst zejména tomu, že rasa byla historicky vlastním jádrem antropologického výzkumu. I přes konceptuální neadekvátnost rasy se antropologie dosud neposunula za koncept rasy jakožto explanační nástroje pro chápání biologické variability lidstva, neboť za něj dosud nemá konceptuální a/nebo metodologickou náhradu. Tento článek nově analyzuje historickou antropologickou literaturu o etnicitě a interakcí mezi biologií a kulturou jako náhradou za koncept rasy a přetváří ji v kontextu moderního filozofického a psychologického pohledu na variabilitu lidské populace