Epidemics in partially overlapped multiplex networks

Many real networks exhibit a layered structure in which links in each layer reflect the function of nodes on different environments. These multiple types of links are usually represented by a multiplex network in which each layer has a different topology. In real-world networks, however, not all nodes are present on every layer. To generate a more realistic scenario, we use a generalized multiplex network and assume that only a fraction $q$ of the nodes are shared by the layers. We develop a theoretical framework for a branching process to describe the spread of an epidemic on these partially overlapped multiplex networks. This allows us to obtain the fraction of infected individuals as a function of the effective probability that the disease will be transmitted $T$. We also theoretically determine the dependence of the epidemic threshold on the fraction $q > 0$ of shared nodes in a system composed of two layers. We find that in the limit of $q \to 0$ the threshold is dominated by the layer with the smaller isolated threshold. Although a system of two completely isolated networks is nearly indistinguishable from a system of two networks that share just a few nodes, we find that the presence of these few shared nodes causes the epidemic threshold of the isolated network with the lower propagating capacity to change discontinuously and to acquire the threshold of the other network.Comment: 13 pages, 4 figure

Effects of temporal correlations in social multiplex networks

Multi-layered networks represent a major advance in the description of natural complex systems, and their study has shed light on new physical phenomena. Despite its importance, however, the role of the temporal dimension in their structure and function has not been investigated in much detail so far. Here we study the temporal correlations between layers exhibited by real social multiplex networks. At a basic level, the presence of such correlations implies a certain degree of predictability in the contact pattern, as we quantify by an extension of the entropy and mutual information analyses proposed for the single-layer case. At a different level, we demonstrate that temporal correlations are a signature of a ‘multitasking’ behavior of network agents, characterized by a higher level of switching between different social activities than expected in a uncorrelated pattern. Moreover, temporal correlations significantly affect the dynamics of coupled epidemic processes unfolding on the network. Our work opens the way for the systematic study of temporal multiplex networks and we anticipate it will be of interest to researchers in a broad array of fields

Aprotinin reduces postoperative bleeding and the need for blood products in thoracic surgery: results of a randomized double-blind study

Objective: Bleeding complications have been a major concern in certain thoracic surgery operations, especially decortication and pulmonary resection for inflammatory pulmonary infection. Prevention of plasminogen activation and fibrinolysis by aprotinin administration has been shown to reduce perioperative bleeding during operations associated with high blood consumption. Methods: Use of blood products (packed red cells, whole blood), chest tube drainage, analgesic requirement, chest tube duration for the patients undergoing major thoracic operations were recorded. In a double blind randomized fashion, patients were assigned to two groups receiving aprotinin (n = 51), at a loading dose of 10(6) kallikrein inhibitory units (KIU) followed by an infusion of the same dose during chest closure or receiving placebo (n = 52). On a daily basis, red-cell percentages of total fluid from drainage bottles were recorded and using the blood hematocrit level of the patient of the day before, the corrected value for the patient's blood volume equivalent of daily drainage was calculated. Results: There was a significant reduction in perioperative use of donor blood (0.98 +/- 0.92 vs. 0.45 +/- 0.32 unite P = 0.0026), and total chest tube drainage (corrected value for the corresponding blood volume) (28.2 +/- 36.9 vs. 76.9 +/- 53.3 ml, P = 0.0004) (mean standard deviation) in the aprotinin group. However, aprotinin did not reduce postoperative transfusion or decrease in hematocrit level due to thoracic operations. In high transfusion-risk thoracic surgery patients (patients who underwent decortication, pulmonary resection for inflammatory lung disease and chest wall resection), the perioperative transfusion was only 0.50 +/- 1.08 units in aprotinin group, compared with 1.94 +/- 0.52 units in control group (P = 0.003). Postoperative transfusion was also reduced in aprotinin administrated group (0.53 +/- 0.56 vs. 1.38 +/- 0.97 units, P = 0.02). The mean total blood loss was decreased to nearly one third of the blood loss of the control group (41 +/- 28 ml vs. 121 +/- 68 ml P = 0.001). Conclusion: Aprotinin significantly reduced perioperative transfusion requirement and postoperative bleeding during major thoracic operations. Aprotinin decreased perioperative transfusion needs. Moreover, patients who were at risk of greater blood loss during and after certain thoracic operations had a greater potential to benefit from prophylactic perioperative aprotinin treatment. (C) 2001 Elsevier Science B.V, All rights reserved

Preoperative Vitamin D Levels and Respiratory Complications of General Anesthesia

Aims: This research aims to investigate whether there is a correlation between the respiratory complications occurring in patients under general anesthesia and preoperative Vitamin D levels. Settings and Design: The study was a prospective observational study. Materials and Methods: This study included 95 adult cases. The cases had total 25-hydroxyvitamin D (25OHD) levels identified in blood samples before the operation. Patients given routine general anesthesia and were assessed in terms of respiratory complications during anesthesia induction, extubation, anesthesia recovery, and the first 24-h postoperative. Statistical Analysis Used: The Shapiro-Wilk test, Student's-t-test, one-way ANOVA test, Pearson correlation coefficient, and Chi-square tests were used. Results: The mean 25OHD vitamin level identified in the preoperative period was 13.00 +/- 6.57 ng/mL, with 25OHD vitamin levels found to be significantly low in female cases compared to male cases (P < 0.05). There was a statistically significant negative relationship between age and 25OHD vitamin levels identified (P = 0.045). When assessed in terms of surgery types, there was no significant difference found in Vitamin D levels in terms of surgery type. When examined for complications in the induction, extubation period, and postoperative recovery period, there was a significant difference identified between 25OHD vitamin levels and these complications (P < 0.01). Conclusions: This research observed that patients with low preoperative 25OHD vitamin levels encountered respiratory complications related to general anesthesia more often. Especially, in the early postoperative period, there is a very significant difference between complications and low 25OHD vitamin levels

Managing Complexity: Towards Intelligent Error-Handling Assistance Trough Interactive Alarm Flood Reduction

Part 2: MAKE Smart FactorInternational audienceThe current trend of integrating machines and factories into cyber-physical systems (CPS) creates an enormous complexity for operators of such systems. Especially the search for the root cause of cascading failures becomes highly time-consuming. Within this paper, we address the question on how to help human users to better and faster understand root causes of such situations. We propose a concept of interactive alarm flood reduction and present the implementation of a first vertical prototype for such a system. We consider this prototype as a first artifact to be discussed by the research community and aim towards an incremental further development of the system in order to support humans in complex error situations