Characterization and antimicrobial efficacy against E. coli of a helium/air plasma at atmospheric pressure created in a plastic package

A plasma source, sustained by the application of a floating high voltage (±15 kV) to parallel-plate electrodes at 50 Hz, has been achieved in a helium/air mixture at atmospheric pressure (P = 105 Pa) contained in a zip-locked plastic package placed in the electrode gap. Some of the physical and antimicrobial properties of this apparatus were established with a view to ascertain its performance as a prototype for the disinfection of fresh produce. The current–voltage (I–V) and charge–voltage (Q–V) characteristics of the system were measured as a function of gap distance d, in the range (3 × 103 ≤ Pd ≤ 1.0 × 104 Pa m). The electrical measurements showed this plasma source to exhibit the characteristic behaviour of a dielectric barrier discharge in the filamentary mode and its properties could be accurately interpreted by the two-capacitance in series model. The power consumed by the discharge and the reduced field strength were found to decrease quadratically from 12.0 W to 4.5 W and linearly from 140 Td to 50 Td, respectively, in the range studied. Emission spectra of the discharge were recorded on a relative intensity scale and the dominant spectral features could be assigned to strong vibrational bands in the 2+ and 1− systems of N2 and ${\rm N}_2^+$ , respectively, with other weak signatures from the NO and OH radicals and the N+, He and O atomic species. Absolute spectral intensities were also recorded and interpreted by comparison with the non-equilibrium synthetic spectra generated by the computer code SPECAIR. At an inter-electrode gap of 0.04 m, this comparison yielded typical values for the electron, vibrational and translational (gas) temperatures of (4980 ± 100) K, (2700 ± 200) K and (300 ± 100) K, respectively and an electron density of 1.0 × 1017 m−3. A Boltzmann plot also provided a value of (3200 ± 200 K) for the vibrational temperature. The antimicrobial efficacy was assessed by studying the resistance of both Escherichia coli K12 its isogenic mutants in soxR, soxS, oxyR, rpoS and dnaK selected to identify possible cellular responses and targets related with 5 min exposure to the active gas in proximity of, but not directly in, the path of the discharge filaments. Both the parent strain and mutants populations were significantly reduced by more than 1.5 log cycles in these conditions, showing the potential of the system. Post-treatment storage studies showed that some transcription regulators and specific genes related to oxidative stress play an important role in the E. coli repair mechanism and that plasma exposure affects specific cell regulator systems.

A benchmark-driven modelling approach for evaluating deployment choices on a multi-core architecture

The complexity of current and emerging architectures provides users with options about how best to use the available resources, but makes predicting performance challenging. In this work a benchmark-driven model is developed for a simple shallow water code on a Cray XE6 system, to explore how deployment choices such as domain decomposition and core affinity affect performance. The resource sharing present in modern multi-core architectures adds various levels of heterogeneity to the system. Shared resources often includes cache, memory, network controllers and in some cases floating point units (as in the AMD Bulldozer), which mean that the access time depends on the mapping of application tasks, and the core's location within the system. Heterogeneity further increases with the use of hardware-accelerators such as GPUs and the Intel Xeon Phi, where many specialist cores are attached to general-purpose cores. This trend for shared resources and non-uniform cores is expected to continue into the exascale era. The complexity of these systems means that various runtime scenarios are possible, and it has been found that under-populating nodes, altering the domain decomposition and non-standard task to core mappings can dramatically alter performance. To find this out, however, is often a process of trial and error. To better inform this process, a performance model was developed for a simple regular grid-based kernel code, shallow. The code comprises two distinct types of work, loop-based array updates and nearest-neighbour halo-exchanges. Separate performance models were developed for each part, both based on a similar methodology. Application specific benchmarks were run to measure performance for different problem sizes under different execution scenarios. These results were then fed into a performance model that derives resource usage for a given deployment scenario, with interpolation between results as necessary.

Asynchronous distributed parallelization of mobile network optimization algorithms

It has been years since the introduction of the Dynamic Network Optimization (DNO) concept, yet the DNO development is still at its infant stage, largely due to a lack of breakthrough in minimizing the lengthy optimization runtime. Our previous work, a distributed parallel solution, has achieved a significant speed gain. To cater for the increased optimization complexity pressed by the uptake of smartphones and tablets, however, this paper examines the potential areas for further improvement and presents a novel asynchronous distributed parallel design that minimizes the inter-process communications. The new approach is implemented and applied to real-life projects whose results demonstrate an augmented acceleration of 7.5 times on a 16-core distributed system compared to 6.1 of our previous solution. Moreover, there is no degradation in the optimization outcome. This is a solid sprint towards the realization of DNO.

Orbital and millenial-scale environmental changes between 64 and 25 ka BP recorded in Black Sea sediments

High-resolution pollen and dinoflagellate cyst records from sediment core M72/5-25-GC1 were used to reconstruct vegetation dynamics in northern Anatolia and surface conditions of the Black Sea between 64 and 20 ka BP. During this period, the dominance of Artemisia in the pollen record indicates a steppe landscape and arid climate conditions. However, the concomitant presence of temperate arboreal pollen suggests the existence of glacial refugia in northern Anatolia. Long-term glacial vegetation dynamics reveal two major arid phases ~64–55 and 40–32 ka BP, and two major humid phases ~54–45 and 28–20 ka BP, correlating with higher and lower summer insolation, respectively. Dansgaard–Oeschger (D–O) cycles are clearly indicated by the 25-GC1 pollen record. Greenland interstadials are characterized by a marked increase in temperate tree pollen, indicating a spread of forests due to warm/wet conditions in northern Anatolia, whereas Greenland stadials reveal cold and arid conditions as indicated by spread of xerophytic biomes. There is evidence for a phase lag of ~500 to 1500 yr between initial warming and forest expansion, possibly due to successive changes in atmospheric circulation in the North Atlantic sector. The dominance of Pyxidinopsis psilata and Spiniferites cruciformis in the dinocyst record indicates brackish Black Sea conditions during the entire glacial period. The decrease of marine indicators (marine dinocysts, acritarchs) at ~54 ka BP and increase of freshwater algae (Pediastrum, Botryococcus) from 32 to 25 ka BP reveals freshening of the Black Sea surface water. This freshening is possibly related to humid phases in the region, to connection between Caspian Sea and Black Sea, to seasonal freshening by floating ice, and/or to closer position of river mouths due to low sea level. In the southern Black Sea, Greenland interstadials are clearly indicated by high dinocyst concentrations and calcium carbonate content, as a result of an increase in primary productivity. Heinrich events show a similar impact on the environment in the northern Anatolia/Black Sea region as Greenland stadials.

Using mobile devices to enhance undergraduate field research

Mobile devices can enhance undergraduate research projects and students’ research capabilities. The use of mobile devices such as tablet computers will not automatically make undergraduates better researchers, but their use should make investigations, writing, and publishing more effective and may even save students time. We have explored some of the possibilities of using “tablets” and “smartphones” to aid the research and inquiry process in geography and bioscience fieldwork. We provide two case studies as illustration of how students working in small research groups use mobile devices to gather and analyze primary data in field-based inquiry. Since April 2010, Apple’s iPad has changed the way people behave in the digital world and how they access their music, watch videos, or read their email much as the entrepreneurs Steve Jobs and Jonathan Ive intended. Now with “apps” and “the cloud” and the ubiquitous references to them appearing in the press and on TV, academics’ use of tablets is also having an impact on education and research. In our discussion we will refer to use of smartphones such as the iPhone, iPod, and Android devices under the term “tablet”. Android and Microsoft devices may not offer the same facilities as the iPad/iphone, but many app producers now provide versions for several operating systems. Smartphones are becoming more affordable and ubiquitous (Melhuish and Falloon 2010), but a recent study of undergraduate students (Woodcock et al. 2012, 1) found that many students who own smartphones are “largely unaware of their potential to support learning”. Importantly, however, students were found to be “interested in and open to the potential as they become familiar with the possibilities” (Woodcock et al. 2012). Smartphones and iPads could be better utilized than laptops when conducting research in the field because of their portability (Welsh and France 2012). It is imperative for faculty to provide their students with opportunities to discover and employ the potential uses of mobile devices in their learning. However, it is not only the convenience of the iPad or tablet devices or smartphones we wish to promote, but also a way of thinking and behaving digitally. We essentially suggest that making a tablet the center of research increases the connections between related research activities.

The politics of slowness and the traps of modernity

This chapter re-evaluates the diachronic, evolutionist model that establishes the Second World War as a watershed between classical and modern cinemas, and ‘modernity’ as the political project of ‘slow cinema’. I will start by historicising the connection between cinematic speed and modernity, going on to survey the veritable obsession with the modern that continues to beset film studies despite the vagueness and contradictions inherent in the term. I will then attempt to clarify what is really at stake within the modern-classical debate by analysing two canonical examples of Japanese cinema, drawn from the geidomono genre (films on the lives of theatre actors), Kenji Mizoguchi’s Story of the Late Chrysanthemums (Zangiku monogatari, 1939) and Yasujiro Ozu’s Floating Weeds (Ukigusa, 1954), with a view to investigating the role of the long take or, conversely, classical editing, in the production or otherwise of a supposed ‘slow modernity’. By resorting to Ozu and Mizoguchi, I hope to demonstrate that the best narrative films in the world have always combined a ‘classical’ quest for perfection with the ‘modern’ doubt of its existence, hence the futility of classifying cinema in general according to an evolutionary and Eurocentric model based on the classical-modern binary. Rather than on a confusing politics of the modern, I will draw on Bazin’s prophetic insight of ‘impure cinema’, a concept he forged in defence of literary and theatrical screen adaptations. Anticipating by more than half a century the media convergence on which the near totality of our audiovisual experience is currently based, ‘impure cinema’ will give me the opportunity to focus on the confluence of film and theatre in these Mizoguchi and Ozu films as the site of a productive crisis where established genres dissolve into self-reflexive stasis, ambiguity of expression and the revelation of the reality of the film medium, all of which, I argue, are more reliable indicators of a film’s political programme than historical teleology. At the end of the journey, some answers may emerge to whether the combination of the long take and the long shot are sufficient to account for a film’s ‘slowness’ and whether ‘slow’ is indeed the best concept to signify resistance to the destructive pace of capitalism.

Behavioral economics, wearable devices, and cooperative games: results from a population-based intervention to increase physical activity

Background: Health care literature supports the development of accessible interventions that integrate behavioral economics, wearable devices, principles of evidence-based behavior change, and community support. However, there are limited real-world examples of large scale, population-based, member-driven reward platforms. Subsequently, a paucity of outcome data exists and health economic effects remain largely theoretical. To complicate matters, an emerging area of research is defining the role of Superusers, the small percentage of unusually engaged digital health participants who may influence other members. Objective: The objective of this preliminary study is to analyze descriptive data from GOODcoins, a self-guided, free-to-consumer engagement and rewards platform incentivizing walking, running and cycling. Registered members accessed the GOODcoins platform through PCs, tablets or mobile devices, and had the opportunity to sync wearables to track activity. Following registration, members were encouraged to join gamified group challenges and compare their progress with that of others. As members met challenge targets, they were rewarded with GOODcoins, which could be redeemed for planet- or people-friendly products. Methods: Outcome data were obtained from the GOODcoins custom SQL database. The reporting period was December 1, 2014 to May 1, 2015. Descriptive self-report data were analyzed using MySQL and MS Excel. Results: The study period includes data from 1298 users who were connected to an exercise tracking device. Females consisted of 52.6% (n=683) of the study population, 33.7% (n=438) were between the ages of 20-29, and 24.8% (n=322) were between the ages of 30-39. 77.5% (n=1006) of connected and active members met daily-recommended physical activity guidelines of 30 minutes, with a total daily average activity of 107 minutes (95% CI 90, 124). Of all connected and active users, 96.1% (n=1248) listed walking as their primary activity. For members who exchanged GOODcoins, the mean balance was 4,000 (95% CI 3850, 4150) at time of redemption, and 50.4% (n=61) of exchanges were for fitness or outdoor products, while 4.1% (n=5) were for food-related items. Participants were most likely to complete challenges when rewards were between 201-300 GOODcoins. Conclusions: The purpose of this study is to form a baseline for future research. Overall, results indicate that challenges and incentives may be effective for connected and active members, and may play a role in achieving daily-recommended activity guidelines. Registrants were typically younger, walking was the primary activity, and rewards were mainly exchanged for fitness or outdoor products. Remaining to be determined is whether members were already physically active at time of registration and are representative of healthy adherers, or were previously inactive and were incentivized to change their behavior. As challenges are gamified, there is an opportunity to investigate the role of superusers and healthy adherers, impacts on behavioral norms, and how cooperative games and incentives can be leveraged across stratified populations. Study limitations and future research agendas are discussed.

Effect of Three Methods for Cleaning Dentures on Biofilms Formed In Vitro on Acrylic Resin

Purpose: The aim of this study was to evaluate the effect of three denture hygiene methods against different microbial biofilms formed on acrylic resin specimens. Materials and methods: The set (sterile stainless steel basket and specimens) was contaminated (37 degrees C for 48 hours) by a microbial inoculum with 106 colony-forming units (CFU)/ml (standard strains: Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Candida albicans, Pseudomonas aeruginosa, and Enterococcus faecalis; field strains: S. mutans, C. albicans, C. glabrata, and C. tropicalis). After inoculation, specimens were cleansed by the following methods: (1) chemical: immersion in an alkaline peroxide solution (Bonyplus tablets) for 5 minutes; (2) mechanical: brushing with a dentifrice for removable prostheses (Dentu Creme) for 20 seconds; and (3) a combination of chemical and mechanical methods. Specimens were applied onto a Petri plate with appropriate culture medium for 10 minutes. Afterward, the specimens were removed and the plates incubated at 37 degrees C for 48 hours. Results: Chemical, mechanical, and combination methods showed no significant difference in the reduction of CFU for S. aureus, S. mutans (ATCC and field strain), and P. aeruginosa. Mechanical and combination methods were similar and more effective than the chemical method for E. faecalis, C. albicans (ATCC and field strain), and C. glabrata. The combination method was better than the chemical method for E. coli and C. tropicalis, and the mechanical method showed intermediate results. Conclusion: The three denture hygiene methods showed different effects depending on the type of microbial biofilms formed on acrylic base resin specimens.

Kappaphycus alvarezii (Rhodophyta, Areschougiaceae) cultivated in subtropical waters in Southern Brazil

Four strains of Kappaphycus alvarezii were cultivated in the subtropical waters of Florianopolis, Santa Catarina State, Brazil (27 degrees 29`19 `` S/48 degrees 32` 28 `` W), from February 2009 to February 2010. Seaweeds were cultivated on floating raft near of mussel farms. Salinity ranged from 29 to 36 psu and temperature from 17.1 to 28.5 degrees C. Higher growth rates (5.12-4.29% day(-1)) were measured in summer and autumn, showing a positive correlation between growth rate and water temperature. Lower growth rates (0.54-0.32% day(-1)) occurred in winter, resulted mainly by biomass loss. Significant differences were observed among the strains in spring and the brown tetrasporophytic strain was the only one which failed to recover, being excluded of the experiments. The effect of cultivation periods (36, 42, and 97 days) on carrageenan yield, gel strength, and viscosity were analyzed. Carrageenan yields were higher for plants kept 42 days in the sea (28%), against 25% for 36 and 97 days. There were no significant differences in carrageenan yield among the strains analyzed. Viscosity increased with the increase of cultivation period, while gel strength seemed to vary at random. Tetrasporangia and cystocarps were not observed, and lost fragments did not attach outside the raft. In general, dissolved inorganic nitrogen concentration decreased around the cultivation area as compared to the mussel farm. Results show that cultivation of K. alvarezii is technically feasible in subtropical waters and can be associated with local mussel farms, mitigating the eutrophication and, eventually, increasing the economic return of the farmers.

A new genus of Ectinosomatidae (Copepoda, Harpacticoida) from sublittoral sediments in Ubatuba, Sao Paulo State (Brazil), an updated key to genera and notes on Noodtiella Wells, 1965

Both sexes of a new genus and species of Ectinosomatidae (Copepoda, Harpacticoida) from sublittoral sediments collected on the inner continental shelf in Ubatuba, Sao Paulo State (Brazil) are described in detail. Chaulionyx gen. n. (type species: C. paivacarvalhoi sp. n.) differs from all known genera in the presence of a conspicuous bifid spine on the prehensile P1 endopod. It can be differentiated from other genera with a prehensile endopod (Halophytophilus Brian, 1919; Bradyellopsis Brian, 1925; Klieosoma Hicks & Schriever, 1985) by the presence of distinctive subrectangular middorsal pores on the urosomites and the unarmed male sixth legs. The genus Lineosoma Wells, 1965 is recognized as a paraphyletic taxon and relegated to a junior subjective synonym of Noodtiella Wells, 1965. Arenosetella pectinata Chappuis, 1954a is removed from its floating position in Ectinosomoides Nicholls, 1945, transferred to the genus Noodtiella as N. pectinata comb. n. and considered the senior subjective synonym of N. toukae Mitwally & Montagna, 2001. Dichotomous keys are provided for the identification of the 18 valid species of Noodtiella and the 21 valid genera of the family Ectinosomatidae. Halophytophilus aberrans Wells & Rao, 1987 is placed species incertae sedis in the family.

PIXE analysis of chromium phytoaccumulation by the aquatic macrophytes Eicchornia crassipes

The uptake of hexavalent chromium in free living floating aquatic macrophytes Eicchornia crassipes cultivated in non-toxic chromium-doped hydroponic solutions is presented. A Cr-uptake bioaccumulation experiment was carried out using healthy macrophytes grown in a temperature controlled greenhouse. Six samples of nutrient media and plants were collected during the 23 day experiment. Roots and leaves were acid digested with the addition of an internal Gallium standard, for thin film sample preparation and quantitative Cr analysis by PIXE method. The Cr(6+) mass uptake by the macrophytes reached up to 70% of the initial concentration, comparable to former results and literature data. The Cr-uptake data were described using a non-structural first order kinetic model. Due to low cost and high removal efficiency, living aquatic macrophytes E. crassipes are a viable biosorbent in an artificial wetland of a water effluent treatment plant. (c) 2009 Elsevier B.V. All rights reserved.

On the release of metronidazole from natural rubber latex membranes

The controlled release of drugs can be efficient if a suitable encapsulation procedure is developed, which requires biocompatible materials to hold and release the drug. In this study, a natural rubber latex (NRL) membrane is used to deliver metronidazole (MET), a powerful antiprotozoal agent. MET was found to be adsorbed on the NRL membrane, with little or no incorporation into the membrane bulk, according to energy dispersive X-ray spectroscopy. X-ray diffraction and FTIR spectroscopy data indicated that MET retained its structural and spectroscopic properties upon encapsulation in the NRL membrane, with no molecular-level interaction that could alter the antibacterial activity of MET. More importantly, the release time of MET in a NRL membrane in vitro was increased from the typical 6-8 h for oral tablets or injections to ca. 100 h. The kinetics of the drug release could be fitted with a double exponential function, with two characteristic times of 3.6 and 29.9 h. This is a demonstration that the induced angiogenesis known to be provided by NRL membranes can be combined with a controlled release of drugs, whose kinetics can be tailored by modifying experimental conditions of membrane fabrication for specific applications. (C) 2010 Elsevier B.V. All rights reserved.

Columnar joints in the Patino Formation sandstones, Eastern Paraguay: a dynamic interaction between dyke intrusion, quartz dissolution and cooling-induced fractures

The Patino Formation sandstones, which crop out in Aregua neighborhood in Eastern Paraguay and show columnar joints near the contact zone with a nephelinite dyke, have as their main characteristics the high proportion of syntaxial quartz overgrowth and a porosity originated from different processes, initially by dissolution and later by partial filling and fracturing. Features like the presence of floating grains in the syntaxial cement, the transitional interpenetrative contact between the silica-rich cement and grains as well as the intense fracture porosity are strong indications that the cement has been formed by dissolution and reprecipitation of quartz from the framework under the effect of thermal expansion followed by rapid contraction. The increase of the silica-rich cement towards the dyke in association with the orthogonal disposition of the columns relative to dyke walls are indicative that the igneous body may represent the main heat source for the interstitial aqueous solutions previously existing in the sediments. At macroscopic scale, the increasing of internal tensions in the sandstones is responsible for the nucleation of polygons, leading to the individualization of prisms, which are interconnected by a system of joints, formed firstly on isotherm surfaces of low temperature and later on successive adjacent planes towards the dyke heat source.

U-curve: A branch-and-bound optimization algorithm for U-shaped cost functions on Boolean lattices applied to the feature selection problem

This paper presents the formulation of a combinatorial optimization problem with the following characteristics: (i) the search space is the power set of a finite set structured as a Boolean lattice; (ii) the cost function forms a U-shaped curve when applied to any lattice chain. This formulation applies for feature selection in the context of pattern recognition. The known approaches for this problem are branch-and-bound algorithms and heuristics that explore partially the search space. Branch-and-bound algorithms are equivalent to the full search, while heuristics are not. This paper presents a branch-and-bound algorithm that differs from the others known by exploring the lattice structure and the U-shaped chain curves of the search space. The main contribution of this paper is the architecture of this algorithm that is based on the representation and exploration of the search space by new lattice properties proven here. Several experiments, with well known public data, indicate the superiority of the proposed method to the sequential floating forward selection (SFFS), which is a popular heuristic that gives good results in very short computational time. In all experiments, the proposed method got better or equal results in similar or even smaller computational time. (C) 2009 Elsevier Ltd. All rights reserved.

Generating segmented meshes from textured color images

This paper presents a new framework for generating triangular meshes from textured color images. The proposed framework combines a texture classification technique, called W-operator, with Imesh, a method originally conceived to generate simplicial meshes from gray scale images. An extension of W-operators to handle textured color images is proposed, which employs a combination of RGB and HSV channels and Sequential Floating Forward Search guided by mean conditional entropy criterion to extract features from the training data. The W-operator is built into the local error estimation used by Imesh to choose the mesh vertices. Furthermore, the W-operator also enables to assign a label to the triangles during the mesh construction, thus allowing to obtain a segmented mesh at the end of the process. The presented results show that the combination of W-operators with Imesh gives rise to a texture classification-based triangle mesh generation framework that outperforms pixel based methods. Crown Copyright (C) 2009 Published by Elsevier Inc. All rights reserved.