Comment on "Scaling feature of magnetic field induced Kondo-peak splittings"

In a recent work Zhang and coworkers (PRB 82, 075111 (2010)) studied the Zeeman splitting of the Kondo resonance for the single impurity Anderson model in a finite magnetic field $B$ with the numerical renormalization group (NRG) method. There, it was found that with increasing magnetic field $B$ the position of the Kondo resonance in the total spectral function \textit{does not} approach its position in the spin resolved spectral function. Additionally, the position of the Kondo maximum exceeded the Zeeman energy for $B/ T_K\gtrsim 5-10$, where $T_K$ is the low energy Kondo scale of the model ($g=2$, $\mu_B=k_B=\hbar=1$). In this comment we argue that both these findings are produced by an improper choice of NRG parameter values. However, we reproduce the crossover in the splitting from Kondo-like behavior to a non-universal splitting larger than the Zeeman energy, but this crossover occurs at much larger fields of the order of the charge scale.Comment: Minor revisions; same version as publishe

New public management reform in European countries: The retreat of the state from telecommunication services

In the post war period, telecommunications - being services of 'general economic interest' - were initially managed by public administrative bodies in many Western European countries. With the rise of New Public Management (NPM) in the 1980s, these bodies were often transformed into public corporations or joint stock companies. Following corporatisation, the provision and the management of these services of general economic interest was gradually transferred to private actors. This paper analyses whether privatisation, as part of NPM reforms, has benefited the consumer. We have, therefore, compiled data on privatisation in the telecommunication sector for 15 European countries from 1980 to 2006. The data set covers the corporatisation process, as well as the transfer of the service provision to the private sector. Three empirical findings stand out: first, the reform processes have differed widely from each other. Second, it's not just the transfer of ownership to the private sector that has ensured efficiency gains and increased consumer benefits; corporatisation has done this as well. Third, efficiency gains have been transferred to the consumer, especially at the beginning of the reform process. -- In der Nachkriegszeit wurden Telekommunikationsdienstleistungen in vielen westeuropäischen Ländern zumeist von Verwaltungseinheiten bereitgestellt. Mit dem Aufkommen des New Public Managements (NPMs) in den 1980er Jahren wurden diese Verwaltungseinheiten in öffentlich-rechtliche Unternehmen oder Aktiengesellschaften umgewandelt (=formelle Privatisierung) und anschließend stückweise an private Akteure übertragen (=materielle Privatisierung). Dieser Beitrag untersucht, ob die Konsumenten von diesen Privatisierungsmaßnahmen profitieren konnten. Zur Beantwortung dieser Frage wurde ein vollständig neuer Paneldatensatz zusammengestellt, mit dem die Privatisierung im Telekommunikationssektor für 15 europäische Länder von 1980 bis 2006 abgebildet werden kann. Der Datensatz umfasst erstmals sowohl formelle als auch materielle Privatisierungsschritte. Drei empirische Ergebnisse sind besonders hervorzuheben. Erstens, der Privatisierungsprozess unterscheidet sich teilweise erheblich zwischen den Ländern. Zweitens, die Konsumenten konnten nicht nur vom Verkauf von Unternehmensanteilen profitieren, sondern auch von formellen Privatisierungsmaßnahmen. Drittens, Effizienzgewinne wurden insbesondere am Anfang des Reformprozesses an die Konsumenten weitergegeben.

An Analytical Model of Packet Collisions in IEEE 802.15.4 Wireless Networks

Numerous studies showed that concurrent transmissions can boost wireless network performance despite collisions. While these works provide empirical evidence that concurrent transmissions may be received reliably, existing signal capture models only partially explain the root causes of this phenomenon. We present a comprehensive mathematical model that reveals the reasons and provides insights on the key parameters affecting the performance of MSK-modulated transmissions. A major contribution is a closed-form derivation of the receiver bit decision variable for arbitrary numbers of colliding signals and constellations of power ratios, timing offsets, and carrier phase offsets. We systematically explore the root causes for successful packet delivery under concurrent transmissions across the whole parameter space of the model. We confirm the capture threshold behavior observed in previous studies but also reveal new insights relevant for the design of optimal protocols: We identify capture zones depending not only on the signal power ratio but also on time and phase offsets.Comment: Accepted for publication in the IEEE Transactions on Wireless Communications under the title "On the Reception of Concurrent Transmissions in Wireless Sensor Networks.

Medical Data Architecture Prototype Development - Summary of Recent Work and Proposed Ideas for Upcoming Work

The Medical Data Architecture (MDA) project supports the Exploration Medical Capability (ExMC) risk to minimize or reduce the risk of adverse health outcomes and decrements in performance due to in-flight medical capabilities on human exploration missions. To mitigate this risk, the ExMC MDA project addresses the technical limitations identified in ExMC Gap Med 07: We do not have the capability to comprehensively process medically-relevant information to support medical operations during exploration missions, and in ExMC Gap Med 10: We do not have the capability to provide computed medical decision support during exploration missions. These gaps recognize the need for a comprehensive medical data management system and the accompanying computational support to provide autonomous medical care during long duration exploration missions. As the MDA maturesincluding the capability to comprehensively process and discover medically-relevant information to support medical operations during exploration missionsproject focus will shift to maturing and extending the MDA platform to enable clinical decision support and real-time guidance. To date, the MDA foundational architecture has recommended exploration medical system Level of Care IV requirements through a series of test bed prototype developments and analog demonstrations. The next stage in the development will focus on more autonomous clinical decision making necessary to address challenges in executing a self-contained medical system that enables health care both with and without assistance from ground support. A thorough understanding of current state of medical decision support systems, advanced machine learning algorithms and vast and varied data sources is required. The development of a clinical decision support for exploration missions (Level of Care V) roadmap is needed: one that assesses of current state of the art of clinical decision support systems (CDSS), interoperability issues, identification of challenges in health and performance monitoring, obtaining and processing information from biosensors, knowledge and data management, data integration and fusion, and advanced algorithm development. This roadmap must also include rapid prototype development in the areas of data processing, advanced analysis and prediction of medical events, and treatment based on medically relevant information processing and evidence-based best practices. In this presentation, an overview of the relevant issues and the beginning framework of a Level of Care V CDSS development roadmap will be provided

Mathematical modelling of the pathogenesis of multiple myeloma-induced bone disease

Multiple myeloma (MM) is the second most common haematological malignancy and results in destructive bone lesions. The interaction between MM cells and the bone microenvironment plays an important role in the development of the tumour cells and MM-induced bone disease and forms a 'vicious cycle' of tumour development and bone destruction, intensified by suppression of osteoblast activity and promotion of osteoclast activity. In this paper, a mathematical model is proposed to simulate how the interaction between MM cells and the bone microenvironment facilitates the development of the tumour cells and the resultant bone destruction. It includes both the roles of inhibited osteoblast activity and stimulated osteoclast activity. The model is able to mimic the temporal variation of bone cell concentrations and resultant bone volume after the invasion and then removal of the tumour cells and explains why MM-induced bone lesions rarely heal even after the complete removal of MM cells. The behaviour of the model compares well with published experimental data. The model serves as a first step to understand the development of MM-induced bone disease and could be applied further to evaluate the current therapies against MM-induced bone disease and even suggests new potential therapeutic targets

Comparison between scattering-states numerical renormalization group and the Kadanoff-Baym-Keldysh approach to quantum transport: Crossover from weak to strong correlations

The quantum transport through nanoscale junctions is governed by the charging energy $U$ of the device. We employ the recently developed scattering-states numerical renormalization group approach to open quantum systems to study nonequilibrium Green functions and current-voltage characteristics of such junctions for small and intermediate values of $U$. The reliability of the approach is established by the excellent agreement with diagrammatic Kadanoff-Baym-Keldysh results at small values of the $U$. We demonstrate the limits of the diagrammatic approaches at intermediate Coulomb repulsion. These approaches predict two different low-energy scale for magnetic and charge fluctuations in zero bias while the numerical renormalization group approach correctly yields only one single, universal scale. At large voltages and intermediate values of the Coulomb repulsion the self-consistent second Born as well as the GW approximation reproduce the SNRG spectral functions quite well for a symmetric junctions, while for the asymmetric model the voltage-dependent redistribution of spectral weight differs significantly. The second-order perturbation theory does not capture the correct single-particle dynamics at large bias and violates current conservation for asymmetric junctions.Comment: To be published in Phys. Rev. B 81, Issue 1

Sentiment Analysis on New York Times Articles Data

Sentiment Analysis on New York Times Coverage Data Departmental Affiliation: Data Science/ Political Science College of Arts and Sciences The extant political science literature examines media coverage of immigration and assesses the effect of that coverage on partisanship in the United States. Immigration is believed to be a unique factor that induces large- scale changes in partisanship based on race and ethnicity. The negative tone of media coverage pushes non-Latino Whites into the Republican Party, while Latinos trend toward the Democratic Party. The aim for this project is to look at New York time data in order to identify how much immigration is covered in newspaper outlets, specifically Latino immigration, and to determine the overall tone of these stories. In this research, we seek to determine individual articles take a positive, neutral or negative stance. We achieve this using a dictionary-based approach, meaning we look at individual words to assess if it has a positive, neutral or negative connotation. We train our data using publicly accessible sentiment dictionaries such as VADER (Valence Aware Dictionary and Sentiment Reasoner). However, this task can be difficult because certain words can be dynamic and may pertain to a positive or negative sentiment in context of the article. In order to resolve this issue, we use reliability measures to ensure that the words of high frequencies are in the correct sphere of negative, neutral, and positive light. Information about the Author(s): Faculty Sponsor(s): Professor Gregg B. Johnson and Professor Karl Schmitt Student Contact: Gabriel Carvajal – [email protected]