Usefulness of gastric intramucosal pH for monitoring hemodynamic complications in critically ill children

OBJECTIVE: To assess the efficacy of gastric intramucosal pH for the evaluation of tissue perfusion and prediction of hemodynamic complications in critically ill children. DESIGN: Open prospective study without controls. SETTING: Pediatric intensive care unit (ICU) of a tertiary care university pediatric hospital. PATIENTS: Thirty critically ill children (16 boys and 14 girls), age range: 3 months-12 years. MEASUREMENTS AND RESULTS: A tonometry catheter was placed in the stomach of all patients on admission to the pediatric ICU. Simultaneous tonometry and arterial gas measurements were made on admittance and every 6-12 h throughout the study; a total of 202 measurements were made. The catheter was removed after extubation and/or when the patient was hemodynamically stable. Intramucosal pH was calculated using the Henderson-Hasselbalch equation based on the pCO2 of the tonometer and arterial bicarbonate. Intramucosal pH values between 7.30 and 7.45 were considered to be normal. The patient's condition was analyzed using the Pediatric Risk Mortality Score (PRISM). The relations between intramucosal pH and the presence of major hemodynamic complications (cardiopulmonary arrest, shock), minor hemodynamic complications (hypotension, hypovolemia or arrhythmia), death, PRISM score and the duration of the stay in the pediatric ICU were analyzed. Intramucosal pH on admission was 7.48 +/- 0.15 on average (range 7.04-7.68). Five patients (16%) had an intramucosal pH lower than 7.30 on admission; these patients did not have a higher incidence of hemodynamic complications. The 16 patients (53%) who had an intramucosal pH of less than 7.30 at some time during the course of their disease had more hemodynamic complications than the patients who did not have pH lower than 7.30 (p < 0.0001). Every case of cardiopulmonary arrest and shock was related to intramucosal pH of less than 7.30. Patients with major complications (cardiopulmonary arrest and shock) had lower intramucosal pHs than those with minor hemodynamic complications (p = 0.03); similarly, they had low intramucosal pH readings more often than those with minor complications (p = 0.0032). Intramucosal pH values less than 7.30 had a sensitivity of 90% and a specificity of 98% as a predictor of hemodynamic complications. There was no relation between intramucosal pH lower than 7.30 and either PRISM or the duration of the stay in the pediatric ICU. Patients with intramucosal pH less than 7.20 had a higher PRISM than the patients who did not have pH lower than 7.20 (p < 0.05). A patient who died during the study due to cardiopulmonary arrest had prior intramucosal pH measurements of 7.23 and 7.10, and three patients died of late complications after the end of the study. Hemodynamic complications were not detected with arterial pH. Gap pH (arterial pH-intramucosal pH) and standard pH measurements yielded the same results as gastric intramucosal pH. CONCLUSION: Intramucosal pH could provide a useful early indication of hemodynamic complications in critically ill children.     

Differences in color naming and color salience in Vietnamese and English

The accepted model of color naming postulates that 11 “basic” color terms representing 11 common perceptual experiences show increased processing salience due to a theorized linkage between perception, visual neurophysiology, and cognition. We tested this theory, originally proposed by Berlin and Kay in 1969. Experiment 1 tested salience by comparing unconstrained color naming across two languages, English and Vietnamese. Results were compared with previous research by Berlin and Kay, Boynton and Olson, and colleagues. Experiment 2 validated our stimuli by comparing OSA, Munsell, and newly rendered “basic” exemplars using colorimetry and behavioral measures. Our results show that the relationship between the visual and verbal domains is more complex than current theory acknowledges. An interpoint distance model of color‐naming behavior is proposed as an alternative perspective on color‐naming universality and color‐category structure. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 113–138, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10131     

Word sense disambiguation for spam filtering

Spam has become a major issue in computer security because it is a channel for threats such as computer viruses, worms, and phishing. More than 86% of received e-mails are spam. Historical approaches to combating these messages, including simple techniques such as sender blacklisting or the use of e-mail signatures, are no longer completely reliable. Many current solutions feature machine-learning algorithms trained using statistical representations of the terms that most commonly appear in such e-mails. However, these methods are merely syntactic and are unable to account for the underlying semantics of terms within messages. In this paper, we explore the use of semantics in spam filtering by introducing a pre-processing step of Word Sense Disambiguation (WSD). Based upon this disambiguated representation, we apply several well-known machine-learning models and show that the proposed method can detect the internal semantics of spam messages.     

Note on the use of the term subject in pre-1886 discussions of thought-transference experiments.

In response to K. Danzinger's (see record 1986-00068-001) suggestion that the first use of the term subject in the English-language psychological literature occurred in 1886 in the context of experiments involving the hypnotic state, the present author points out that there are examples of the use of the term in discussions of experiments on thought transference published by the Society for Psychical Research in the 1880's. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A review on the combination of binary classifiers in multiclass problems

Several real problems involve the classification of data into categories or classes. Given a data set containing data whose classes are known, Machine Learning algorithms can be employed for the induction of a classifier able to predict the class of new data from the same domain, performing the desired discrimination. Some learning techniques are originally conceived for the solution of problems with only two classes, also named binary classification problems. However, many problems require the discrimination of examples into more than two categories or classes. This paper presents a survey on the main strategies for the generalization of binary classifiers to problems with more than two classes, known as multiclass classification problems. The focus is on strategies that decompose the original multiclass problem into multiple binary subtasks, whose outputs are combined to obtain the final prediction.     

Lagrangean relaxation with clusters for point-feature cartographic label placement problems

This paper presents two new mathematical formulations for the point-feature cartographic label placement problem (PFCLP) and a new Lagrangean relaxation with clusters (LagClus) to provide bounds to these formulations. The PFCLP can be represented by a conflict graph and the relaxation divides the graph in small subproblems (clusters) that are easily solved. The edges connecting clusters are relaxed in a Lagrangean way and a subgradient algorithm improves the bounds. The LagClus was successfully applied to a set of instances up to 1000 points providing the best results of those reported in the literature.     

MPC for tracking piecewise constant references for constrained linear systems

In this paper, a novel model predictive control (MPC) for constrained (non-square) linear systems to track piecewise constant references is presented. This controller ensures constraint satisfaction and asymptotic evolution of the system to any target which is an admissible steady-state. Therefore, any sequence of piecewise admissible setpoints can be tracked without error. If the target steady state is not admissible, the controller steers the system to the closest admissible steady state.These objectives are achieved by: (i) adding an artificial steady state and input as decision variables, (ii) using a modified cost function to penalize the distance from the artificial to the target steady state (iii) considering an extended terminal constraint based on the notion of invariant set for tracking. The control law is derived from the solution of a single quadratic programming problem which is feasible for any target. Furthermore, the proposed controller provides a larger domain of attraction (for a given control horizon) than the standard MPC and can be explicitly computed by means of multiparametric programming tools. On the other hand, the extra degrees of freedom added to the MPC may cause a loss of optimality that can be arbitrarily reduced by an appropriate weighting of the offset cost term.     

Malicious uses of blockchains by malware: from the analysis to Smart-Zephyrus

The permanent availability and relative obscurity of blockchains is the perfect ground for using them for malicious purposes. However, the use of blockchains by malwares has not been characterized yet. This paper analyses the current state of the art in this area. One of the lessons learned is that covert communications for malware have received little attention. To foster further defence-oriented research, a novel mechanism (dubbed Smart-Zephyrus) is built leveraging smart contracts written in Solidity. Our results show that it is possible to hide 4 Kb of secret in 41 s. While being expensive (around USD 1.82 per bit), the provided stealthiness might be worth the price for attackers.

     

Effect of warm mix additives on the interfacial bonding characteristics of asphalt binders

The quality of the interfacial bonding between asphalt binder and aggregates plays a significant role in determining the durability of asphalt mixtures. Warm mix asphalt (WMA) modifiers have been used extensively in the last decade primarily to reduce production and compaction temperatures as well as to improve workability of asphalt mixtures. This study aimed to provide better understanding of the effects of these WMA modifiers on the interfacial bonding between asphalt binders and aggregates. The evaluation focused on measuring surface energy of binders in unaged and aged states and aggregates and then calculating energy parameters that describe the potential of a given asphalt-aggregate combination to resist fatigue cracking and moisture damage. Results show that the combination of asphalt-WMA additive, as well as the content applied of WMA additive has a significant impact on the fatigue cracking and moisture damage resistance. The results suggest that it is poor practice to use a given type and percentage of WMA modifier without regard for binder type. Instead, test methods are recommended to evaluate the compatibility of asphalt binder, WMA additive type/content, and aggregates for improved performance at different conditions.     

Adaptive inter-layer message routing in 3D networks-on-chip

Existing routing algorithms for 3D deal with regular mesh/torus 3D topologies. Today 3D NoCs are quite irregular, especially those with heterogeneous layers. In this paper, we present a routing algorithm targeting 3D networks-on-chip (NoCs) with incomplete sets of vertical links between adjacent layers. The routing algorithm tolerates multiple link and node failures, in the case of absence of NoC partitioning. In addition, it deals with congestion. The routing algorithm for 3D NoCs preserves the deadlock-free propriety of the chosen 2D routing algorithms. It is also scalable and supports a local reconfiguration that complements the reconfiguration of the 2D routing algorithms in case of failures of nodes or links. The algorithm incurs a small overhead in terms of exchanged messages for reconfiguration and does not introduce significant additional complexity in the routers. Theoretical analysis of the 3D routing algorithm is provided and validated by simulations for different traffic loads and failure rates.