5,505 results for 2012

  • Cosmic structure, averaging and dark energy

    Wiltshire, D.L. (2012)

    Conference Contributions - Other
    University of Canterbury Library

    5 invited lectures

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  • Methods for identifying plant materials in Māori and Pacific textiles

    Lowe, Bronwyn J; Smith, Catherine A (2012)

    Conference paper
    University of Otago

    Investigating the range of plant species used in Māori and Pacific textiles can help to understand the diversity and relationships among whatu and raranga techniques and art forms. Although the style and construction of Māori and Pacific textile artefacts often give clues as to the plant species used, positive species identification is not always possible from visual inspection. This may be due to the age and condition of the artefact, or effects of leaf processing such as splitting, softening, stripping or dying. A range of laboratory methods and published resources are however available to help with the identification process. Understanding the internal and surface anatomy of raw leaf material (e.g. Carr and Cruthers 2007; Carr et. al. 2009), the effects of leaf preparation for weaving on leaf anatomy (e.g. King 2003) and the expected condition of specimens sampled from artefacts can aid the interpretation of data collected in the laboratory. The most appropriate method of specimen preparation is another important consideration. This paper provides a review of microscopy and tomography techniques and online resources, which have been trialled and implemented in the Clothing and Textile Sciences Department at the University of Otago for the identification of plant species of interest in New Zealand and the Pacific. The advantages and disadvantages of these techniques and resources for identifying plant materials in artefacts will be discussed.

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  • Multiscale rescaled range analysis of EEG recordings in sevoflurane anesthesia

    Liang, Z; Li, D; Ouyang, G; Wang, Y; Voss, Logan; Sleigh, James; Li, X (2012-04)

    Journal article
    The University of Auckland Library

    OBJECTIVE: The Hurst exponent (HE) is a nonlinear method measuring the smoothness of a fractal time series. In this study we applied the HE index, extracted from electroencephalographic (EEG) recordings, as a measure of anesthetic drug effects on brain activity. METHODS: In 19 adult patients undergoing sevoflurane general anesthesia, we calculated the HE of the raw EEG; comparing the maximal overlap discrete wavelet transform (MODWT) with the traditional rescaled range (R/S) analysis techniques, and with a commercial index of depth of anesthesia - the response entropy (RE). We analyzed each wavelet-decomposed sub-band as well as the combined low frequency bands (HEOLFBs). The methods were compared in regard to pharmacokinetic/pharmacodynamic (PK/PD) modeling, and prediction probability. RESULTS: All the low frequency band HE indices decreased when anesthesia deepened. However the HEOLFB was the best index because: it was less sensitive to artifacts, most closely tracked the exact point of loss of consciousness, showed a better prediction probability in separating the awake and unconscious states, and tracked sevoflurane concentration better - as estimated by the PK/PD models. CONCLUSIONS: The HE is a useful measure for estimating the depth of anesthesia. It was noted that HEOLFB showed the best performance for tracking drug effect. SIGNIFICANCE: The HEOLFB could be used as an index for accurately estimating the effect of anesthesia on brain activity.

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  • Gap junctions modulate seizures in a mean-field model of general anesthesia for the cortex

    Steyn-Ross, ML; Steyn-Ross, DA; Sleigh, James (2012-06)

    Journal article
    The University of Auckland Library

    During slow-wave sleep, general anesthesia, and generalized seizures, there is an absence of consciousness. These states are characterized by low-frequency large-amplitude traveling waves in scalp electroencephalogram. Therefore the oscillatory state might be an indication of failure to form coherent neuronal assemblies necessary for consciousness. A generalized seizure event is a pathological brain state that is the clearest manifestation of waves of synchronized neuronal activity. Since gap junctions provide a direct electrical connection between adjoining neurons, thus enhancing synchronous behavior, reducing gap-junction conductance should suppress seizures; however there is no clear experimental evidence for this. Here we report theoretical predictions for a physiologically-based cortical model that describes the general anesthetic phase transition from consciousness to coma, and includes both chemical synaptic and direct electrotonic synapses. The model dynamics exhibits both Hopf (temporal) and Turing (spatial) instabilities; the Hopf instability corresponds to the slow (≲8 Hz) oscillatory states similar to those seen in slow-wave sleep, general anesthesia, and seizures. We argue that a delicately balanced interplay between Hopf and Turing modes provides a canonical mechanism for the default non-cognitive rest state of the brain. We show that the Turing mode, set by gap-junction diffusion, is generally protective against entering oscillatory modes; and that weakening the Turing mode by reducing gap conduction can release an uncontrolled Hopf oscillation and hence an increased propensity for seizure and simultaneously an increased sensitivity to GABAergic anesthesia.

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  • A theoretical and experimental investigation of roof flexibility on internal and net roof pressure dynamics in low-rise buildings with a dominant opening’

    Guha, TK; Sharma, Rajnish; Richards, Peter (2012)

    Journal article
    The University of Auckland Library

    A theoretical and experimental study of the effect of roof flexibility on the dynamics of internal and net roof pressure is reported in thsi paper. A two-degree-of-freedom dynamic model and its simplified counterpart, the single-degree-of-freedom quasi-static model is sued for theoretical analysis. As an illustrative example, admittance and spectra of internal and net roof pressure is presented for a medium-sized industrial building with different roof flexibilities using these models. Complementary wind tunnel investigations using a felixible Styrofoam roof are carried out to validate the model predictions. Additionally, effect of the dominant opening size and wind direction (i.e. angle of attack) on internal pressure for the flexible roof is experimentally investigated in the wind tunnel with a comparison to those for a rigid roof model.

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  • Translating Love

    Dureau, Christine (2012-06)

    Journal article
    The University of Auckland Library

    This article addresses relationships between personal experience and cross-cultural understanding of maternal love. I analyze claims of mutual maternal understanding by women on Simbo, Western Solomon Islands, highlighting the contexts in which they expressed love in compassionate terms and the interplay of fieldwork intersubjectivity. Although assumptions of a priori emotional comprehension grounded in apparently similar experiences are problematic, it is possible to develop degrees of mutual emotional knowledge through the exchanges of participant-observation. The concept of “emotional communities” serves as a fruitful way of conceptualizing both the diverse contexts in which people express aspects of taru (love) and the emotional engagement of cross-cultural fieldwork.

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  • Anti-consumption and society: Proceedings of ICAR 2012 Brisbane

    Lee, Michael; Cherrier, H; Rundle-Thiele, S (2012)

    Book
    The University of Auckland Library

    Griffith Business School is committed to research that develops and promotes social, financial and environmental approaches that lead to sustainable businesses and communities. In Volume 2, Issue 3 of the Journal of Social Marketing, Gerard Hastings asks “When a supermarket chain attains such dominance that it covers every corner of a country the size of the UK, threatens farmers’ livelihoods with its procurement practices, undercuts local shops and bullies planners into submission, it becomes reasonable to ask: does every little bit really help? Once the 100 billionth burger has been flipped and yet another trouser button popped it is sensible to wonder: are we still lovin’ it? As the planet heats up in response to our ever increasing and utterly unsustainable levels of consumption, it is fair to question: are we really worth it?” (Hastings, 2012). Ongoing attention needs to be directed by the research community to understand the impact that our consumption behaviour has on ourselves, our loved ones, our society, and our planet. Research attention that challenges society to question its own practices is central in assisting us to understand how we can build sustainable communities. The International Centre for Anti-consumption Research (ICAR) 2012 symposium encourages us to question whether our aim to live independently is ideal. A child’s desire to leave home may promote economic growth, but does little to keep loved ones and communities closely connected. Sustainable business practice models are needed if we are to step away from the economic growth model that underpins business today. Sharing rather than consuming may be one mechanism that business can use to reengineer business practice. Research presented at ICAR 2012 suggests that to achieve sustainable business and communities we need to understand the opposition and resistance, including boycotts that have emerged against business. This understanding is rapidly evolving in an Internet- dominated era where social media landscapes are mushrooming. To develop a more social approach that leads to sustainable business and consumption, researchers must understand that anti-consumption is not an exact opposite of consumption. A range of behaviours and their underlying motives remain under-researched, and avenues to broaden our focus are showcased at ICAR 2012. Sustainability requires that individuals and communities engage in a diverse range of behaviours including decreasing resource use (water, energy, and materials). A practical stance is introduced at ICAR 2012 with empirical evidence highlighting how community-based social marketing is being used throughout the world to foster sustainable behaviour change.

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  • Recommendations for rescue of a submerged unresponsive compressed-gas diver.

    Mitchell, SJ; Bennett, MH; Bird, N; Doolette, DJ; Hobbs, GW; Kay, E; Moon, RE; Neuman, TS; Vann, RD; Walker, R; Wyatt, HA (2012-11)

    Journal article
    The University of Auckland Library

    The Diving Committee of the Undersea and Hyperbaric Medical Society has reviewed available evidence in relation to the medical aspects of rescuing a submerged unresponsive compressed-gas diver. The rescue process has been subdivided into three phases, and relevant questions have been addressed as follows. Phase 1, preparation for ascent: If the regulator is out of the mouth, should it be replaced? If the diver is in the tonic or clonic phase of a seizure, should the ascent be delayed until the clonic phase has subsided? Are there any special considerations for rescuing rebreather divers? Phase 2, retrieval to the surface: What is a "safe" ascent rate? If the rescuer has a decompression obligation, should they take the victim to the surface? If the regulator is in the mouth and the victim is breathing, does this change the ascent procedures? If the regulator is in the mouth, the victim is breathing, and the victim has a decompression obligation, does this change the ascent procedures? Is it necessary to hold the victim's head in a particular position? Is it necessary to press on the victim's chest to ensure exhalation? Are there any special considerations for rescuing rebreather divers? Phase 3, procedure at the surface: Is it possible to make an assessment of breathing in the water? Can effective rescue breaths be delivered in the water? What is the likelihood of persistent circulation after respiratory arrest? Does the recent advocacy for "compression-only resuscitation" suggest that rescue breaths should not be administered to a non-breathing diver? What rules should guide the relative priority of in-water rescue breaths over accessing surface support where definitive CPR can be started? A "best practice" decision tree for submerged diver rescue has been proposed.

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  • Dispersion of windborne debris

    Richards, Peter (2012-05)

    Journal article
    The University of Auckland Library

    The dispersion of windborne debris that is caused by the object's aerodynamics and shape is investigated. It is shown that the flight may be divided into two phases. The initial phase, where the relative velocity is high and the rate of rotation low, is characterised by high transverse accelerations. The second phase, which has much lower accelerations, can be modelled as that of a compact object, where only the drag force is significant. The initial conditions for the second phase are determined by the initial phase. Approximate solutions to the equations of motion are proposed for rectangular plate and rod type debris. The results are is good agreement with wind tunnel observations.

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  • Pressures on a cubic building-Part 2: Quasi-steady and other processes

    Richards, Peter; Hoxey, RP (2012-03)

    Journal article
    The University of Auckland Library

    This paper explores the relationship between the turbulent flow within the atmospheric boundary layer and the surface pressure on a building, the Silsoe 6. m cube, immersed deep within that boundary layer. In the past, the main approach has been to examine the statistical properties of both surface pressure and boundary layer flow independently as correlations are poor. However, accepting that the statistical properties of the flow at a point within the boundary layer at a given height are invariant with location, it is then shown that the quasi-steady analytical technique can account for much of the measured surface pressure fluctuations. The simplified quasi-steady-vector model, which relates surface pressure to variations in dynamic pressure and wind direction, is shown to give close comparison with measured values for the standard deviation, the maximum and the minimum surface pressure. The remaining differences are discussed and explained. © 2011 Elsevier Ltd.

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  • Pressures on a cubic building-Part 1: Full-scale results

    Richards, Peter; Hoxey, RP (2012-03)

    Journal article
    The University of Auckland Library

    Pressures on the vertical and horizontal centrelines of the Silsoe 6m cube are presented. The full-scale data has been processed in 12. min non-overlapping record blocks of cube surface tap pressure together with the reference upstream approach flow measured at cube height. Since in full-scale one has to accept the wind conditions provided by nature, each block of data is unique in regards to even the mean conditions and there is no opportunity to exactly replicate a test multiple times, as might be done in a wind tunnel. As a result the data are processed in a manner that makes use of the large number of blocks recorded. Pressure coefficients are determined by normalising with the wind dynamic pressure at the reference position. The mean, standard deviation, maximum and minimum pressure coefficients are determined by normalising the measured pressures by the mean, standard deviation and maximum wind dynamic pressure, respectively. It is concluded that using this normalising process helps to minimise the uncertainty of the results. A least squares optimisation method is used to fit a truncated Fourier series to the pressure coefficient data over the 360° of flow direction. The differences between the data points and the fitted curves are used to assess the uncertainty associated with each type of coefficient. It is shown that typically 90% of the normalised data lies within a band of ±0.1 for the mean pressure coefficient and ±18% for the standard deviation coefficient. However with the maximum and minimum pressure coefficients the uncertainty is higher and asymmetric, and is best modelled as a combination of a fixed amount plus a percentage of the coefficient. The highest uncertainty noted was for the minimum coefficient where 90% of the data lies between about +0.1-16% of the coefficient and -0.1+25% of the coefficient. It is shown that all of the pressure coefficients determined form a consistent set, which exhibit sensible variations with both position and wind direction. It is believed that this set of data offers opportunities for the assessment of wind tunnel and CFD models, which has not been previously possible.

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  • Pressure field of a rotating square plate with application to windborne debris

    Martinez-Vazquez, P; Kakimpa, B; Sterling, M; Baker, CJ; Quinn, AD; Richards, Peter; Owen, JS (2012-11)

    Journal article
    The University of Auckland Library

    Traditionally, a quasi steady response concerning the aerodynamic force and moment coefficients acting on a flat plate while \'flying\' through the air has been assumed. Such an assumption has enabled the flight paths of windborne debris to be predicted and an indication of its potential damage to be inferred. In order to investigate this assumption in detail, a series of physical and numerical simulations relating to flat plates subject to autorotation has been undertaken. The physical experiments have been carried out using a novel pressure acquisition technique which provides a description of the pressure distribution on a square plate which was allowed to auto-rotate at different speeds by modifying the velocity of the incoming flow. The current work has for the first time, enabled characteristic pressure signals on the surface of an auto-rotating flat plate to be attributed to vortex shedding.

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  • Internal pressure in a building with multiple dominant openings in a single wall: Comparison with the single opening situation

    Guha, TK; Sharma, Rajnish; Richards, Peter (2012-08)

    Journal article
    The University of Auckland Library

    A generalized theoretical model of internal pressure dynamics in a building with multiple openings on a single wall with highly correlated external pressure is developed. Analytical and wind tunnel studies on a model building for the case of two closely spaced dominant openings in a single wall showed that internal pressure in such configurations increase with increase in the ratio of opening sizes, and become almost equal, but slightly less than that for the most critical single opening configuration under normal onset flow, when the combined area of the two openings become double the critical single opening size. For wind angles within ±45-70°, the Root Mean Square (RMS) and the peak ratio internal pressure coefficients for the two-opening configuration of area ratio unity are found to be much higher than the most critical single opening configuration due to the "tangential flow" excitation through the openings provided by the two near-simultaneous oblique jet flows. For the sidewall two-opening configurations corresponding to wind angles 100-140°, the RMS internal pressure fluctuations are found to be somewhat suppressed due to flow short-circuiting through the two openings resulting from flow separation and external pressure gradient. The internal pressure provisions of AS/NZS 1170.2.2011 for internal pressure design in buildings with potential multiple openings on a single wall are found to be adequate for most wind angles.

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  • Capital Gains Tax: Lessons from Across the Ditch

    Cassidy, Julie; Alley, C (2012-06)

    Journal article
    The University of Auckland Library

    Unlike most OECD countries, New Zealand has never implemented a realisation-based capital gains tax (CGT). During the recent 2011 election the Labour Party announced its plans to change this position, broadening the New Zealand tax base by introducing a CGT. The Labour Party’s tax policies drew heavily from the Australian taxation system. However, the Labour Party only set out the broad framework for the proposed new tax. As the Australian experience shows, the devil is often in the detail. To date the primary reason offered against introducing a CGT in New Zealand has been its complexity. The Australian experience shows that there are a number of design features that can make a CGT complex and undermine the potential benefits of the tax. Ultimately it is suggested that while a CGT should be introduced into the New Zealand tax regime, it should be designed to avoid the problems encountered in Australia. Lessons can certainly be learned from across the ditch.

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  • Sustainability and coincidence of riparian vegetation and in-stream macroinvertebrate communities in Auckland's water sensitive developments

    van Roon, Marjorie; Rigold, TPM (2012)

    Conference item
    The University of Auckland Library

    Water Sensitive Urban Design has much in common with the New Zealand (NZ) practice, Low Impact Urban Design and Development (LIUDD). In New Zealand, both terrestrial and aquatic ecosystem protection and re-creation are essential elements of greenfield developments that conform to LIUDD. This paper reports on investigations into stream and terrestrial riparian plant communities within gulley environments in headwater LIUDD sub-catchments in Manukau, Auckland. The monitoring of stream macro-invertebrates and riparian plant communities reveals the degree of coincidence of the health of these complimentary habitats. Additionally, the sustainability of planted riparian communities in adjacent countryside living sub-catchments was investigated. Vegetation was sampled using the NZ Vegetation Survey Recce method. Characteristics recorded included ground cover, top height, canopy-cover and species composition. Statistical methods showed how forest structure and composition changed in relation to three factors: age, by individual site, and by management. Management was assessed from landowner interviews. Results showed expected and adequate growth of planted trees, the need for further control of weeds, and very low rates of natural seedling establishment. This information is used to predict the sustainability of these plant communities and to provide advice to landowners on appropriate interventions including supplementary planting of future forest canopy species.

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  • The Death of a Key Symbol

    Dureau, Christine (2012-03)

    Journal article
    The University of Auckland Library

    Sherry Ortner's concept of key symbols has been a mainstay in symbolic studies since its publication in 1973, but it has been little developed since then. This paper proffers temporality as a significant, but largely overlooked element of some key symbols. A case study of an old-woman's death on Simbo, Western Solomon Islands, demonstrates how key symbols may emerge and decline rapidly in contexts of uncertainty and political negotiation.

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  • The use of alignment in ancient near Eastern mathematics

    Ford, Rebecca (2012)

    Reports
    University of Canterbury Library

    Cuneiform texts from the ancient near east include the oldest written mathematics in the world. These texts did not use symbolism to communicate mathematical operations, unlike modern mathematics. The hypothesis of this study was that alignment was used to perform a similar function. To investigate this, the study examined the formatting of different cur1eiform tables, which inherently used alignment to imply an operation. A range of tabular development was included, from the simple, informal tables to sophisticated headed, complex tables. The study also looked at the use of alignment on 'rough working' arithmetical exercise texts, and identified two formats in which multiplication exercises were arranged. The study concluded that although alignment was used to show operations, this was a weak convention compared with the more prolific practices of left-justification, explicit statements through words and the concrete progression of logic from left to right along a line.

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  • Unresponsiveness ≠ unconsciousness

    Sanders, RD; Tononi, G; Laureys, S; Sleigh, James (2012-04)

    Journal article
    The University of Auckland Library

    Consciousness is subjective experience. During both sleep and anesthesia, consciousness is common, evidenced by dreaming. A defining feature of dreaming is that, while conscious, we do not experience our environment; we are disconnected. Besides inducing behavioral unresponsiveness, a key goal of anesthesia is to prevent the experience of surgery (connected consciousness), by inducing either unconsciousness or disconnection of consciousness from the environment. Review of the isolated forearm technique demonstrates that consciousness, connectedness, and responsiveness uncouple during anesthesia; in clinical conditions, a median 37% of patients demonstrate connected consciousness. We describe potential neurobiological constructs that can explain this phenomenon: during light anesthesia the subcortical mechanisms subserving spontaneous behavioral responsiveness are disabled but information integration within the corticothalamic network continues to produce consciousness, and unperturbed norepinephrinergic signaling maintains connectedness. These concepts emphasize the need for developing anesthetic regimens and depth of anesthesia monitors that specifically target mechanisms of consciousness, connectedness, and responsiveness.

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  • Investigating paradoxical hysteresis effects in the mouse neocortical slice model

    Voss, LJ; Brock, M; Carlsson, C; Steyn-Ross, A; Steyn-Ross, M; Sleigh, JW (2012-01-30)

    Journal article
    The University of Auckland Library

    Clinically, anesthetic drugs show hysteresis in the plasma drug concentrations at induction versus emergence from anesthesia induced unconsciousness. This is assumed to be the result of pharmacokinetic lag between the plasma and brain effect-site and vice versa. However, recent mathematical and experimental studies demonstrate that anesthetic hysteresis might be due in part to lag in the brain physiology, independent of drug transport delay - so-called "neural inertia". The aim of this study was to investigate neural inertia in the reduced neocortical mouse slice model. Seizure-like event (SLE) activity was generated by exposing cortical slices to no-magnesium artificial cerebrospinal fluid (aCSF). Concentration-effect loops were generated by manipulating SLE frequency, using the general anesthetic drug etomidate and by altering the aCSF magnesium concentration. The etomidate (24 μM) concentration-effect relationship showed a clear hysteresis, consistent with the slow diffusion of etomidate into slice tissue. Manipulation of tissue excitability, using either carbachol (50 μM) or elevated potassium (5mM vs 2.5mM) did not significantly alter the size of etomidate hysteresis loops. Hysteresis in the magnesium concentration-effect relationship was evident, but only when the starting condition was magnesium-containing "normal" aCSF. The in vitro cortical slice manifests pathway-dependent "neural inertia" and may be a valuable model for future investigations into the mechanisms of neural inertia in the cerebral cortex.

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  • Testing neocortical slice viability in non-perfused no-magnesium artificial cerebrospinal fluid solutions

    Voss, LJ; George, SA; Sleigh, JW (2012-03-15)

    Journal article
    The University of Auckland Library

    The acute in vitro brain slice model is a widely used neurophysiological research tool. When applying this method, most researchers continuously perfuse slices with carbogenated artificial cerebrospinal fluid (ACSF) to maintain pH balance and tissue oxygen delivery. Common wisdom suggests that static recordings are incompatible with submerged bath methodology because of deficiency in tissue oxygen supply. However, to our knowledge this has not been tested. In this study, we wanted to determine whether neocortical mouse slice viability could be maintained in the medium term (up to 2h) in a shallow, submerged recording bath under non-perfused, static conditions. Seizure-like events (SLEs) were generated in the slices utilizing no-magnesium ACSF and recorded for 2h under three conditions: (1) perfused ACSF condition (n=8), where slices were perfused continuously with carbogenated no-magnesium ACSF; (2) static ACSF condition (n=12), where slices were recorded in pre-carbogenated, but non-perfused (static) no-magnesium ACSF; and (3) static HEPES ACSF condition (n=12), where slices were recorded in non-perfused (static) no-magnesium ACSF with no pre-carbogenation but buffered with HEPES. SLE activity was stable for 2h across all three conditions. There was no statistically significant difference in SLE frequency, amplitude or length between static and perfused conditions. SLE frequency and amplitude were generally lower in the static HEPES buffer condition. The data indicate that robust and stable neocortical SLE activity can be generated for at least 2h in a submersion bath without ACSF perfusion if pH is adequately controlled.

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