Functional brain organization of preparatory attentional control in visual search

Looking for an object that may be present in a cluttered visual display requires an advanced specification of that object to be created and then matched against the incoming visual input. Here, fast event-related fMRI was used to identify the brain networks that are active when preparing to search for a visual target. By isolating the preparation phase of the task it has been possible to show that for an identical stimulus, different patterns of cortical activation occur depending on whether participants anticipate a 'feature' or a 'conjunction' search task. When anticipating a conjunction search task, there was more robust activation in ventral occipital areas, new activity in the transverse occipital sulci and right posterior intraparietal sulcus. In addition, preparing for either type of search activated ventral striatum and lateral cerebellum. These results suggest that when participants anticipate a demanding search task, they develop a different advanced representation of a visually identical target stimulus compared to when they anticipate a nondemanding search. © 2013 Elsevier B.V. All rights reserved

Spontaneous lucid dreaming frequency and waking insight

Spontaneous lucid dreaming is characterized by the realization that the currently perceived reality is in fact a dream. As this ability differs between individuals, specific cognitive abilities have been sought that might explain this variability. Here, “insight,” a key feature of spontaneous lucid dreaming, is investigated. Frequent, occasional, and nonlucid dreamers were compared on their successful performance of a compound remote associate problem-solving task, designed to measure insight. Results show that frequent lucid dreamers solve significantly more insight problems overall than nonlucid dreamers. This suggests that the insight experienced during the dream state may relate to the same underlying cognition needed for insight in the waking state. (PsycINFO Database Record (c) 2014 APA, all rights reserved

Examining the triggers of lucid insight

Approximately half the population have experienced a lucid dream. Yet, it is not well understood how an individual realises they are dreaming (i.e. lucid insight). A few studies suggest it can be triggered by a nightmare, or by the identification of inconsistencies/dream-like qualities/peculiarities. The present study aimed to produce a detailed typology of lucidity triggers to inform consideration of the nature of associated thought processes. 91 lucid dreamers were identified in an undergraduate sample of 148. Lucid dreamers were asked to describe what it was, if anything, that had made them realise they were dreaming. Thematic analysis of responses extracted evidence of four overarching triggers consistent with previous research: identification of an abnormality, identification of a dream-like quality, an emotionally-arousing dream event, and miscellaneous. It was uniquely identified that ‘abnormalities’ within the dream were those inconsistent with waking knowledge rather than with the accompanying dream content. Novel triggers were identified that were classifiable as subthemes under the previously-identified triggers, and triggers co-occurred in a third of cases. Novel triggers included ‘déjà rêvé’, the feeling that one has dreamt the experience before, as well as ‘self-comfort/denial’ involving an emotionally-driven denial of the reality of a distressing dream. Nightmare-induced lucidity appeared to arise via qualitatively diverse paths: via self-comfort/denial and/or via the identification of abnormalities/dream-like qualities. The nature of the triggers indicates that higher-order cognition can precede, and promote, lucid insight. This sheds light on a key theoretical issue of whether lucid insight is a pre-requisite for the re-emergence of higher-order cognition. Keywords: lucid dreaming, lucidity, nightmares, higher-order cognition, phenomenology

An ERP study of visual search showing early detection of feature conjunctions

An ERP study of visual search showing early detection of feature conjunction

Neural mechanisms of top-down control during visual search: effects of template complexity

Neural mechanisms of top-down control during visual search: effects of template complexit

Hydrogen Peroxide and Beyond - the Potential of High-Voltage Plasma Activated Liquids Against Cancerous Cells

Abstract: The use of plasma-activated liquids such as PBS, medium or simply plasma-activated water (PAW) has been receiving increasing attention for applications in cancer treatments. Amongst the reactive species contained in these solutions, hydrogen peroxide appears to play a pivotal role in causing cytotoxic effects. While H2O2 concentrations can be correlated with reduced cell viability and growth and used as an indicator of the potential efficacy of a plasma-activated water, comparisons to standard H2O2 kill curves demonstrate a potency in PAW which exceeds H2O2 associated toxicity, indicating that other plasma-generated species play an important role. Using a high-voltage dielectric barrier atmospheric cold plasma (DBD-ACP) system, we demonstrate the generation of plasma-activated water with high cytotoxic potential and good storage stability. The potency of the activated solutions can be modulated using system or process characteristics such as voltage level, treatment time and post-treatment storage time and target-related characteristics such as surface to volume ratio. All of these parameters were found to impact cell viability in a hydrogen peroxide concentration; correlated manner. The susceptibility of two cancer cell lines to PAW was similar to that observed for two non-cancer cell lines and the toxicity of plasma-activated water exceeded that of the corresponding hydrogen peroxide concentrations. This study examines the role of H2O2 in PAW-mediated cytotoxic effects on different mammalian cell lines and investigates the effects beyond H2O2 employing a set-up where short-lived reactive species can be discounted and activated liquids with long-term stability are generated. Here we investigate the cytotoxic mediators generated in water specific to high-voltage DBD-ACP

Controlled Cytotoxicity of Plasma Treated Water Formulated By Open-air Hybrid Mode Discharge

Plasma‐activated liquids (PAL) attract increasing interest with demonstrated biological effects. Plasma exposure in air produces stable aqueous reactive species which can serve as chemical diagnostics of PAL systems. Here, we tailor aqueous reactive species inside plasma‐activated water (PAW) through treating water with AC air spark and glow discharges in contact with water. Chemical probing demonstrated species specificity between two types of PAW. Spark discharge PAW contains urn:x-wiley:14381656:media:ppap201600207:ppap201600207-math-0006 and urn:x-wiley:14381656:media:ppap201600207:ppap201600207-math-0007, while urn:x-wiley:14381656:media:ppap201600207:ppap201600207-math-0008and urn:x-wiley:14381656:media:ppap201600207:ppap201600207-math-0009 are generated in glow discharge PAW. Species formation in different PAWs have been discussed in terms of discharge mechanisms and liquid phase chemistry process. Species specificity can provide richer parametric spaces for producing PALs with controlled impact and dosage achievable by combining discharge modes or mixing different PALs

Cold Plasma Inactivation of Internalised Bacteria and Biofilms for Salmonella Enterica Serovar Typhimurium, Listeria Monocytogenes and Escherichia Coli

Microbial biofilms and bacteria internalised in produce tissue may reduce the effectiveness of decontamination methods. In this study, the inactivation efficacy of in-package atmospheric cold plasma (ACP) afterglow was investigated against Salmonella Typhimurium, Listeria monocytogenes and Escherichia coli in the forms of planktonic cultures, biofilms formed on lettuce and associated bacteria internalised in lettuce tissue. Prepared lettuce broth (3%) was inoculated with bacteria resulting in a final concentration of ~ 7.0 log10 CFU/ml. For biofilm formation and internalisation, lettuce pieces (5 × 5 cm) were dip-inoculated in bacterial suspension of ~ 7.0 log10 CFU/ml for 2 h and further incubated for 0, 24 and 48 h at either 4 °C or room temperature (~ 22 °C) in combination with light/dark photoperiod or at 4 °C under dark conditions. Inoculated samples were sealed inside a rigid polypropylene container and indirectly exposed (i.e. placed outside plasma discharge) to a high voltage (80 kVRMS) air ACP with subsequent storage for 24 h at 4 °C. ACP treatment for 30 s reduced planktonic populations of Salmonella, L. monocytogenes and E. coli suspended in lettuce broth to undetectable levels. Depending on storage conditions, bacterial type and age of biofilm, 300 s of treatment resulted in reduction of biofilm populations on lettuce by a maximum of 5 log10 CFU/sample. Scanning electron and confocal laser microscopy pointed to the incidence of bacterial internalisation and biofilm formation, which influenced the inactivation efficacy of ACP. Measured intracellular reactive oxygen species (ROS) revealed that the presence of organic matter in the bacterial suspension might present a protective effect against the action of ROS on bacterial cells. This study demonstrated that high voltage in-package ACP could be a potential technology to overcome bacterial challenges associated with food produce. However, the existence of biofilms and internalised bacteria should be considered for further optimisation of ACP treatment parameters in order to achieve an effective control of the realistic challenges posed by foodborne pathogens

CUSUM design for detection of event-rate increases for a Poisson process

In quantifying the performance of a CUSUM chart for detecting upward shifts in event rate, it has been recommended that steady-state evaluation of performance measures such as ARL be used. In this article, the methodology for making such evaluations using the Markov-chain approach is presented, for the case of an exponential CUSUM. This is much more efficient than the alternative of simulation, which is still in use. It is also shown that if one is using steady-state ARL as a measure of detection performance, one can find better choices for the CUSUM parameter k than that provided by the SPRT-based formula. Two types of shift in event rate are considered, and corresponding tables of recommended choices of CUSUM parameters (k, h) are presented for ten levels of in-control ARL, and for nine sizes of shift. These tables can assist quality engineers in the design of CUSUMs for monitoring inter-event times in steady-state operation. It is also shown that these exponential CUSUM tables may be used to find values for the parameters of a geometric CUSUM or a Bernoulli CUSUM chart for monitoring a proportion, provided the in-control value of the proportion is no more than approximately 0.5

Detecting a downward shift in a proportion using a geometric CUSUM chart

In monitoring an ordered stream of discrete items from a repetitive process, the geometric CUSUM chart may be used to detect sudden shifts from an acceptable level for a process-proportion (p) such as fraction nonconforming. Much of the investigative effort for this CUSUM scheme has been concentrated on the detection of upward shifts, and a recent paper has provided guidance to quality engineers in choosing the parameters (k, h) of such a scheme. In this article, the corresponding task of aiding the choice of parameters for detecting a downward shift is addressed. It is shown, using extensive numerical investigations, that the use of a value for the parameter k based on the Sequential Probability Ratio is not optimal when one is using steady-state evaluation of the detection performance of the CUSUM scheme. Tables are presented listing recommended values of parameters for detection of five sizes of downward shift, for each of 27 in-control levels for p in the range 0.20 to 0.001. Interpolation and extrapolation to find parameter values for other in-control levels of p are also considered, and a range of examples presented. There is an equivalence between a geometric CUSUM scheme and a Bernoulli CUSUM scheme, so that the results of this investigation may also be used in choosing parameter values for a Bernoulli CUSUM chart