Interacting Turing-Hopf Instabilities Drive Symmetry-Breaking Transitions in a Mean-Field Model of the Cortex: A Mechanism for the Slow Oscillation

Electrical recordings of brain activity during the transition from wake to anesthetic coma show temporal and spectral alterations that are correlated with gross changes in the underlying brain state. Entry into anesthetic unconsciousness is signposted by the emergence of large, slow oscillations of electrical activity (≲1  Hz) similar to the slow waves observed in natural sleep. Here we present a two-dimensional mean-field model of the cortex in which slow spatiotemporal oscillations arise spontaneously through a Turing (spatial) symmetry-breaking bifurcation that is modulated by a Hopf (temporal) instability. In our model, populations of neurons are densely interlinked by chemical synapses, and by interneuronal gap junctions represented as an inhibitory diffusive coupling. To demonstrate cortical behavior over a wide range of distinct brain states, we explore model dynamics in the vicinity of a general-anesthetic-induced transition from “wake” to “coma.” In this region, the system is poised at a codimension-2 point where competing Turing and Hopf instabilities coexist. We model anesthesia as a moderate reduction in inhibitory diffusion, paired with an increase in inhibitory postsynaptic response, producing a coma state that is characterized by emergent low-frequency oscillations whose dynamics is chaotic in time and space. The effect of long-range axonal white-matter connectivity is probed with the inclusion of a single idealized point-to-point connection. We find that the additional excitation from the long-range connection can provoke seizurelike bursts of cortical activity when inhibitory diffusion is weak, but has little impact on an active cortex. Our proposed dynamic mechanism for the origin of anesthetic slow waves complements—and contrasts with—conventional explanations that require cyclic modulation of ion-channel conductances. We postulate that a similar bifurcation mechanism might underpin the slow waves of natural sleep and comment on the possible consequences of chaotic dynamics for memory processing and learning

Forensic Investigation of Google Assistant

Google Nest devices have seen a rise in demand especially with Google’s huge advantage in search engine results and a complex ecosystem that consists of a range of companion devices and compatible mobile applications integrated and interacting with its virtual assistant, Google Assistant. This study undertakes the forensics extraction and analysis of client-centric and cloud-native data remnants left behind on Android smartphones by the Google Home and Google Assistant apps used to control a Google Nest device. We identified the main database and file system storage location central to the Google Assistant ecosystem. From our analysis, we show forensic artifacts of interest associated with user account information, the chronology and copies of past voice conversations exchanged, and record of deleted data. The findings from this study describe forensic artifacts that could assist forensic investigators and can facilitate a criminal investigation

VIC ... High Yielding, Strong Gluten Durum

'Vic' (CI 17789) is a durum wheat cultivar (variety) developed by the North Dakota Agricultural Experiment Station, North Dakota State University, in cooperation with Agricultural Research, Science and Education Administration, the U. S. Department of Agriculture. Vic combines high grain yield and strong gluten characteristics. Gluten strength gives superior cooked firmness to various pasta products made from durum semolina. The improved yielding ability and strong gluten of Vic should make it a potential replacement for all presently grown normal height cultivars. Vic was developed in only six years from the final cross by utilizing early generation (F 3) yield and quality testing and three years of winter nurseries

Perfect design or practical study? A workshop on navigating the challenges of community based prevention research

Subject: There is a shared interest among public health researchers in tackling methodological issues surrounding community based research, and on moving beyond a focus on individual level change. As part of a project on community empowerment funded by the People’s Health Trust, we have conducted a feasibility study on quantitative and economic evaluation of complex community-based interventions. To understand different quantitative methods that can be used to evaluate community empowerment interventions, we have undertaken a methodological literature review that identified the following sets of challenges: Defining population of interest – interventions taking place at a community level are not specifically targeted at a well-defined group of individuals. Therefore it is challenging to even find those who are affected by an intervention. Diverse and un-prescribed effects – the effect of community empowerment interventions are likely broad, suggesting we need to measure multiple outcomes in order to detect change. This increases the likelihood of detecting spurious change and can require a lot of resource. Furthermore, in many cases these outcomes are not pre-defined by a programme (i.e. communities choose their own foci)

Annotated bibliography 1986-1990

The following compilation represents the third installment of Oral Tradition's ongoing annotated bibliography of scholarship relevant to the field. This addition, covering the years 1986-1990, maintains the goals of the first two installments: 1) to update John Miles Foley's original bibliography, Oral-Formulaic Theory and Research (Garland 1985), which provided an annotated listing of scholarship on the Parry-Lord theory of oral composition up until 1982, and 2) to expand the scope of the bibliography into other fields related to the study of oral traditions. The initial year of this installment also marks the beginning of Oral Tradition itself, and all articles published in the journal from 1986-1990 are herein annotated.Not

Rheology of Lava Flows on Europa and the Emergence of Cryovolcanic Domes

There is ample evidence that Europa is currently geologically active. Crater counts suggest that the surface is no more than 90 Myr old, and cryovolcanism may have played a role in resurfacing the satellite in recent geological times. Europa's surface exhibits many putative cryovolcanic features, and previous investigations have suggested that a number of domes imaged by the Galileo spacecraft may be volcanic in origin. Consequently, several Europa domes have been modeled as viscous effusions of cryolava. However, previous models for the formation of silicic domes on the terrestrial planets contain fundamental shortcomings. Many of these shortcomings have been alleviated in our new modeling approach, which warrants a re-assessment of the possibility of cryovolcanic domes on Europa

Emplacement of Volcanic Domes on Venus and Europa

Placing firmer constraints on the emplacement timescales of visible volcanic features is essential to obtaining a better understanding of the resurfacing history of Venus. Fig. 1 shows a Magellan radar image and topography for a putative venusian lava dome. 175 such domes have been identified, having diameters that range from 19 - 94 km, and estimated thicknesses as great as 4 km [1-2]. These domes are thought to be volcanic in origin [3], having formed by the flow of a viscous fluid (i.e., lava) onto the surface. Among the unanswered questions surrounding the formation of Venus steep-sided domes are their emplacement duration, composition, and the rheology of the lava. Rheologically speaking, maintenance of extremely thick, 1-4 km flows necessitates higher viscosity lavas, while the domes' smooth upper surfaces imply the presence of lower viscosity lavas [2-3]. Further, numerous quantitative issues, such as the nature and duration of lava supply, how long the conduit remained open and capable of supplying lava, the volumetric flow rate, and the role of rigid crust in influencing flow and final morphology all have implications for subsurface magma ascent and local surface stress conditions. The surface of Jupiter's icy moon Europa exhibits many putative cryovolcanic constructs [5-7], and previous workers have suggested that domical positive relief features imaged by the Galileo spacecraft may be volcanic in origin [5,7-8] (Fig. 2). Though often smaller than Venus domes, if emplaced as a viscous fluid, formation mechanisms for europan domes may be similar to those of venusian domes [7]. Models for the emplacement of venusian lava domes (e.g. [9-10]) have been previously applied to the formation of putative cryolava domes on Europa [7]

Production of hybrid granitic magma at the advancing front of basaltic underplating: Inferences from the Sesia Magmatic System (south-western Alps, Italy)

The Permian Sesia Magmatic System of the southwestern Alps displays the plumbing system beneath a Permian caldera, including a deep crustal gabbroic complex, upper crustal granite plutons and a bimodal volcanic field dominated by rhyolitic tuff filling the caldera. Isotopic compositions of the deep crustal gabbro overlap those of coeval andesitic basalts, whereas granites define a distinct, more radiogenic cluster (Sri 480.708 and 0.710, respectively). AFC computations starting from the best mafic candidate for a starting melt show that Nd and Sr isotopic compositions and trace elements of andesitic basalts may be modeled by reactive bulk assimilation of 4830% of partially depleted crust and 4815%\u201330% gabbro fractionation. Trace elements of the deep crustal gabbro cumulates require a further 4860% fractionation of the andesitic basalt and loss of 4840% of silica-rich residual melt. The composition of the granite plutons is consistent with a mixture of relatively constant proportions of residual melt delivered from the gabbro and anatectic melt. Chemical and field evidence leads to a conceptual modelwhich links the production of the two granitic components to the evolution of theMafic Complex. During the growth of the Mafic Complex, progressive incorporation of packages of crustal rocks resulted in a roughly steady state rate of assimilation. Anatectic granite originates in the hot zone of melting crust located above the advancing mafic intrusion. Upward segregation of anatectic melts facilitates the assimilation of the partially depleted restite by stoping. At each cycle of mafic intrusion and incorporation, residual and anatectic melts are produced in roughly constant proportions, because the amount of anatectic melt produced at the roof is a function of volume and latent heat of crystallization of the underplated mafic melt which in turn produces proportional amounts of hybrid gabbro cumulates and residualmelt. Such a process can explain the restricted range in isotopic compositions of most rhyolitic and granitic rocks of the Permo-Carboniferous province of Europe and elsewhere