Aseptic Meningitis Due to Spontaneous Rupture of a Multicystic Craniopharyngioma with an Ommaya Catheter: A Case Report.

Craniopharyngiomas (CPs) are benign tumors that are believed to arise from embryonic remnants of the Rathke pouch epithelium. Herein, we report a case of aseptic meningitis due to spontaneous rupture of multicystic CP, which contained an Ommaya catheter. A 19-year-old boy was admitted to the hospital with a 4-day history of acute severe headache after strenuous physical exercise followed by altered sensorium, fever, and neck stiffness. Cerebrospinal fluid (CSF) analysis revealed marked pleocytosis and elevated protein levels. CSF culture was otherwise negative. Cyst reduction on subsequent imaging confirmed the diagnosis. The patient received intravenous steroid therapy and was discharged asymptomatic. This is a rare evolution of a multicystic CP, which was previously treated with intracystic therapy and had an Ommaya catheter. Clinicians should be aware of spontaneous CP rupture and look actively for the occurrence of cholesterol crystals or elevated CSF levels of cholesterol as well as prompt follow-up imaging.

A new approach of H∞ filtering for combustion systems using optical instrumentation.

This paper proposes a new filtering scheme applied to a linearized model of a nonlinear representation for combustion systems, whose parameters are obtained by means of optical sensors. To ensure a robust representation regarding the chosen operation point and external disturbances variations, a linear parameter-varying (LPV) state-space representation is proposed in terms of noise disturbances and time-varying parameters affecting the plant (like the instrumentation noise and non-laminar air flow). Concerning the proposed filtering scheme, a new observer structure, which includes the incorporation of the control signal as an additional input of the filter, is proposed to assure improved stability margins and performance given in terms of the H∞ norm. The filter design method is based on a convex optimization technique and is capable to deal with unstable dynamics. A numerical experiment, whose data were obtained from an actual combustion plant, illustrates the flexibility and advantages of the method when compared with the maximum correntropy criterion based Kalman filter, the full-order filter and the standard Luenberger observer.

A Novel Theoretical Probabilistic Model for Opportunistic Routing with Applications in Energy Consumption for WSNs.

This paper proposes a new theoretical stochastic model based on an abstraction of the opportunistic model for opportunistic networks. The model is capable of systematically computing the network parameters, such as the number of possible routes, the probability of successful transmission, the expected number of broadcast transmissions, and the expected number of receptions. The usual theoretical stochastic model explored in the methodologies available in the literature is based on Markov chains, and the main novelty of this paper is the employment of a percolation stochastic model, whose main benefit is to obtain the network parameters directly. Additionally, the proposed approach is capable to deal with values of probability specified by bounded intervals or by a density function. The model is validated via Monte Carlo simulations, and a computational toolbox (R-packet) is provided to make the reproduction of the results presented in the paper easier. The technique is illustrated through a numerical example where the proposed model is applied to compute the energy consumption when transmitting a packet via an opportunistic network.

Protocol for Energy-Efficiency in Networked Control Systems Based on WSN.

This paper proposes a new communication protocol for output-feedback control through multi-hop Wireless Sensor Network (WSN). The protocol is based on a Hop-by-Hop transport scheme and is especially devised to simultaneously fulfill two conflicting criteria: the network energy consumption and the stability/performance (in terms of H∞ norm) of the closed-loop system. The proposed protocol can be implemented by means of three heuristics, basically using distinct rules to control the maximum number of retransmissions allowed in terms of the voltage level of the batteries of the network nodes. As another contribution, a Markov jump based representation is proposed to model the packet loss in the communication channel, giving rise to a systematic procedure to determine the transition probability matrix and the Markov chain operation modes of a network with multiple information sources. The synthesis of the output-feedback controller is made in two steps (observer filter plus a state-feedback controller) for the Markov model assuming partial availability of the operation modes. The efficiency and applicability of the communication protocol is illustrated by means of a numerical experiment, based on a physical model of a coupled tanks plant. The features of each heuristic of implementation of the proposed protocol are presented in the numerical comparisons.

Conserved queen pheromones in bumblebees: a reply to Amsalem et al.

In a recent study, Amsalem, Orlova & Grozinger (2015) performed experiments with Bombus impatiens bumblebees to test the hypothesis that saturated cuticular hydrocarbons are evolutionarily conserved signals used to regulate reproductive division of labor in many Hymenopteran social insects. They concluded that the cuticular hydrocarbon pentacosane (C25), previously identified as a queen pheromone in a congeneric bumblebee, does not affect worker reproduction in B. impatiens. Here we discuss some shortcomings of Amsalem et al.'s study that make its conclusions unreliable. In particular, several confounding effects may have affected the results of both experimental manipulations in the study. Additionally, the study's low sample sizes (mean n per treatment = 13.6, range: 4-23) give it low power, not 96-99% power as claimed, such that its conclusions may be false negatives. Inappropriate statistical tests were also used, and our reanalysis found that C25 substantially reduced and delayed worker egg laying in B. impatiens. We review the evidence that cuticular hydrocarbons act as queen pheromones, and offer some recommendations for future queen pheromone experiments.

Diploid Male Production Results in Queen Death in the Stingless Bee Scaptotrigona depilis.

As in most Hymenoptera, the eusocial stingless bees (Meliponini) have a complementary sex determination (CSD) system. When a queen makes a "matched mating" with a male that shares a CSD allele with her, half of their diploid offspring are diploid males rather than females. Matched mating imposes a cost, since diploid male production reduces the colony workforce. Hence, adaptations preventing the occurrence or attenuating its effects are likely to arise. Here we provide clear evidence that in the stingless bee Scaptotrigona depilis, the emergence of diploid males induces queen death, and this usually occurs within 10-20 days of the emergence of diploid male offspring from their pupae. Queens that have not made a matched mating die when introduced into a colony in which diploid males are emerging. This shows that the adult diploid males, and not the queen that has made a matched mating herself, are the proximate cause of queen death. Analysis of the cuticular hydrocarbon profiles of adult haploid and diploid males shows six compounds with significant differences. Moreover, the diploid and haploid males only acquire distinct cuticular hydrocarbon profiles 10 days after emergence. Our data shows that the timing of queen death occurs when the cuticular hydrocarbons of haploid and diploid males differ significantly, suggesting that these chemical differences could be used as cues or signals to trigger queen death.

The origin and evolution of social insect queen pheromones: Novel hypotheses and outstanding problems.

Queen pheromones, which signal the presence of a fertile queen and induce daughter workers to remain sterile, are considered to play a key role in regulating the reproductive division of labor of insect societies. Although queen pheromones were long thought to be highly taxon-specific, recent studies have shown that structurally related long-chain hydrocarbons act as conserved queen signals across several independently evolved lineages of social insects. These results imply that social insect queen pheromones are very ancient and likely derived from an ancestral signalling system that was already present in their common solitary ancestors. Based on these new insights, we here review the literature and speculate on what signal precursors social insect queen pheromones may have evolved from. Furthermore, we provide compelling evidence that these pheromones should best be seen as honest signals of fertility as opposed to suppressive agents that chemically sterilize the workers against their own best interests.