Index statistical properties of sparse random graphs

Using the replica method, we develop an analytical approach to compute the characteristic function for the probability $\mathcal{P}_N(K,\lambda)$ that a large $N \times N$ adjacency matrix of sparse random graphs has $K$ eigenvalues below a threshold $\lambda$. The method allows to determine, in principle, all moments of $\mathcal{P}_N(K,\lambda)$, from which the typical sample to sample fluctuations can be fully characterized. For random graph models with localized eigenvectors, we show that the index variance scales linearly with $N \gg 1$ for $|\lambda| > 0$, with a model-dependent prefactor that can be exactly calculated. Explicit results are discussed for Erd\"os-R\'enyi and regular random graphs, both exhibiting a prefactor with a non-monotonic behavior as a function of $\lambda$. These results contrast with rotationally invariant random matrices, where the index variance scales only as $\ln N$, with an universal prefactor that is independent of $\lambda$. Numerical diagonalization results confirm the exactness of our approach and, in addition, strongly support the Gaussian nature of the index fluctuations.Comment: 10 pages, 5 figure

Connections between collinear and transverse-momentum-dependent polarized observables within the Collins-Soper-Sterman formalism

We extend the improved Collins-Soper-Sterman (iCSS) $W+Y$ construction recently presented in~\cite{Collins:2016hqq} to the case of polarized observables, where we focus in particular on the Sivers effect in semi-inclusive deep-inelastic scattering. We further show how one recovers the expected leading-order collinear twist-3 result from a (weighted) $q_T$-integral of the differential cross section. We are also able to demonstrate the validity of the well-known relation between the (TMD) Sivers function and the (collinear twist-3) Qiu-Sterman function within the iCSS framework. This relation allows for their interpretation as functions yielding the average transverse momentum of unpolarized quarks in a transversely polarized spin-$\frac{1}{2}$ target. We further outline how this study can be generalized to other polarized quantities.Comment: 14 pages, Version to be published in PL

Small Business Social Media Use, Innovative Work Behavior, and Organizational Performance

This article quantitatively examines the relationships between social media use, innovative work behavior, and organizational performance among small businesses in the United States. A theoretical model containing these latent variables was developed using the assumptions established by the Resource-Based View Theory and the Diffusion of Innovations Theory. Survey data from United States small business employees was collected and subsequently analyzed using partial least squares structural equation modeling (PLS-SEM). Statistically significant positive relationships between each of the examined variables were found. Recommendations involving the use of social media by small businesses to improve employee innovative work behavior and organizational performance were made

Do Editorial policies support ethical research? A thematic text analysis of author instructions in psychiatry journals

Introduction: According to the Declaration of Helsinki and other guidelines, clinical studies should be approved by a research ethics committee and seek valid informed consent from the participants. Editors of medical journals are encouraged by the ICMJE and COPE to include requirements for these principles in the journal's instructions for authors. This study assessed the editorial policies of psychiatry journals regarding ethics review and informed consent. Methods and Findings: The information given on ethics review and informed consent and the mentioning of the ICMJE and COPE recommendations were assessed within author's instructions and online submission procedures of all 123 eligible psychiatry journals. While 54% and 58% of editorial policies required ethics review and informed consent, only 14% and 19% demanded the reporting of these issues in the manuscript. The TOP-10 psychiatry journals (ranked by impact factor) performed similarly in this regard. Conclusions: Only every second psychiatry journal adheres to the ICMJE's recommendation to inform authors about requirements for informed consent and ethics review. Furthermore, we argue that even the ICMJE's recommendations in this regard are insufficient, at least for ethically challenging clinical trials. At the same time, ideal scientific design sometimes even needs to be compromised for ethical reasons. We suggest that features of clinical studies that make them morally controversial, but not necessarily unethical, are analogous to methodological limitations and should thus be reported explicitly. Editorial policies as well as reporting guidelines such as CONSORT should be extended to support a meaningful reporting of ethical research

The Lessons from Libor for Detection and Deterrence of Cartel Wrongdoing

In late June 2012, Barclays entered into a $453 million settlement with UK and U.S. regulators due to its manipulation of Libor between 2005 and 2009. Among the agencies that investigated Barclays is the Department of Justice Antitrust Division (as well as other antitrust authorities and regulatory agencies from around the world). Participation in a price fixing conduct, by its very nature, requires the involvement of more than one firm. We are cautious to draw overly broad conclusions until more facts come out in the public domain. What we note at this time, based on public information, is that the Libor conspiracy and manipulation seems not to be the work of a rogue trader. Rather it seems to have been organized across firms and required the active knowledge of a number of individuals at relatively high levels of seniority among certain Libor setting banks. Collusion across firms is at the core of illegal antitrust behavior. The Supreme Court has deemed the pernicious effects of cartels so central to antitrust’s mission that it has stated that cartels are “the supreme evil of antitrust.” The involvement of more than one bank in such a cartel is a significant corporate governance failure due to the coordination that such a cartel would have required among the various cartel members. That the Libor cartel seems to have occurred in such a highly regulated industry after a wave of corporate governance reforms post-Enron and a push to greater internal compliance in the early 2000s is perhaps even more surprising. Yet, the very nature of what may have occurred regarding Libor manipulation, in hindsight, seems rather obvious. The rate did not move for over a year until the day before the financial crisis of 2009 hit. Also, quotes by the member banks that were submitted under seal moved simultaneously to the same number from one day to the next during that time period. Had any member bank that set Libor or indeed any antitrust authority undertaken an econometric screen, they would have detected these anomalies, undertaken a more in-depth investigation and discovered the wrongdoing. This essay explores the use of econometric screens as a tool to improve detection of potential price fixing cartel behavior as a method to police the firm from illegal behavior either by enforcement authorities or via firms themselves