Information acquisition and financial contagion.

This paper incorporates costly voluntary acquisition of information à la Nikitin and Smith (2007) [Nikitin, M., Smith, R.T., 2007. Information acquisition, coordination, and fundamentals in a financial crisis. Journal of Banking and Finance, in press, doi:10.1016/j.jbankfin.2007.04.031], in a framework similar to Allen and Gale (2000) [Allen, F., Gale, D., 2000. Financial contagion. Journal of Political Economy 108, 1–33], without relying on any unexpected shock to model contagion. In this framework, contagion and financial crises are the result of information gathering by depositors, weak fundamentals and an incomplete market structure of banks. It also shows how financial systems entering a recession can affect others with apparently stronger economic conditions (contagion). Finally, this is the first paper to investigate the effectiveness of the Contingent Credit Line procedures, introduced by the IMF at the end of the nineties, as a mechanism to prevent the propagation of crises.Central Bank; Contingent credit line; Financial contagion; Fundamentals; Verification equilibrium;

PeerHunter: Detecting Peer-to-Peer Botnets through Community Behavior Analysis

Peer-to-peer (P2P) botnets have become one of the major threats in network security for serving as the infrastructure that responsible for various of cyber-crimes. Though a few existing work claimed to detect traditional botnets effectively, the problem of detecting P2P botnets involves more challenges. In this paper, we present PeerHunter, a community behavior analysis based method, which is capable of detecting botnets that communicate via a P2P structure. PeerHunter starts from a P2P hosts detection component. Then, it uses mutual contacts as the main feature to cluster bots into communities. Finally, it uses community behavior analysis to detect potential botnet communities and further identify bot candidates. Through extensive experiments with real and simulated network traces, PeerHunter can achieve very high detection rate and low false positives.Comment: 8 pages, 2 figures, 11 tables, 2017 IEEE Conference on Dependable and Secure Computin

Large N and the renormalization group

In the large N limit, we show that the Local Potential Approximation to the flow equation for the Legendre effective action, is in effect no longer an approximation, but exact - in a sense, and under conditions, that we determine precisely. We explain why the same is not true for the Polchinski or Wilson flow equations and, by deriving an exact relation between the Polchinski and Legendre effective potentials (that holds for all N), we find the correct large N limit of these flow equations. We also show that all forms (and all parts) of the renormalization group are exactly soluble in the large N limit, choosing as an example, D dimensional O(N) invariant N-component scalar field theory.Comment: 13 pages, uses harvmac; Added: one page with further clarification of the main results, discussion of earlier work, and new references. To be published in Phys. Lett.

Properties of derivative expansion approximations to the renormalization group

Approximation only by derivative (or more generally momentum) expansions, combined with reparametrization invariance, turns the continuous renormalization group for quantum field theory into a set of partial differential equations which at fixed points become non-linear eigenvalue equations for the anomalous scaling dimension $\eta$. We review how these equations provide a powerful and robust means of discovering and approximating non-perturbative continuum limits. Gauge fields are briefly discussed. Particular emphasis is placed on the r\^ole of reparametrization invariance, and the convergence of the derivative expansion is addressed.Comment: (Minor touch ups of the lingo.) Invited talk at RG96, Dubna, Russia; 14 pages including 2 eps figures; uses LaTeX, epsf and sprocl.st

Culture-specific programs for children and adults from minority groups who have asthma (Review)

Background People with asthma who come from minority groups have poorer asthma outcomes and more asthma related visits to Emergency Departments (ED). Various programmes are used to educate and empower people with asthma and these have previously been shown to improve certain asthma outcomes. Models of care for chronic diseases in minority groups usually include a focus of the cultural context of the individual and not just the symptoms of the disease. Therefore, questions about whether culturally specific asthma education programmes for people from minority groups are effective at improving asthma outcomes, are feasible and are cost-effective need to be answered. Objectives To determine whether culture-specific asthma programmes, in comparison to generic asthma education programmes or usual care, improve asthma related outcomes in children and adults with asthma who belong to minority groups. Search strategy We searched the Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialised Register, MEDLINE, EMBASE, review articles and reference lists of relevant articles. The latest search was performed in May 2008. Selection criteria All randomised controlled trials (RCTs) comparing the use of culture-specific asthma education programmes with generic asthma education programmes, or usual care, in adults or children from minority groups who suffer from asthma. Data collection and analysis Two review authors independently selected, extracted and assessed the data for inclusion. We contacted authors for further information if required. Main results Four studies were eligible for inclusion in the review. A total of 617 patients, aged from 5 to 59 years were included in the meta-analysis of data. Use of a culture-specific programme was superior to generic programmes or usual care, in improving asthma quality of life scores in adults, pooled WMD 0.25 (95% CI 0.09 to 0.41), asthma knowledge scores in children, WMD 3.30 (95% CI 1.07 to 5.53), and in a single study, reducing asthma exacerbation in children (risk ratio for hospitalisations 0.32, 95% CI 0.15, 0.70). Authors' conclusions Current limited data show that culture-specific programmes for adults and children from minority groups with asthma, are more effective than generic programmes in improving most (quality of life, asthma knowledge, asthma exacerbations, asthma control) but not all asthma outcomes. This evidence is limited by the small number of included studies and the lack of reported outcomes. Further trials are required to answer this question conclusively