Hemodynamic and electrophysiological evidence of resting-state network activity in the primate

An expanding body of literature describes the existence of concerted brain activations in the absence of any external stimuli. Resting-state networks have been identified and demonstrated to be modulated during the performance of specific cognitive operations. However, despite mounting evidence the possibility still remains that those correlated signal fluctuations reflect non-neural phenomena. In order to isolate functionally relevant spontaneous coactivations, we utilized a multi-level sampling approach to obtain co-registered brain signals across a range of sampling resolution and sensitivity. Surface and local field potentials, hemodynamic signals (near-infrared spectroscopy, NIRS), and cell spiking were recorded from dorsolateral prefrontal and posterior parietal cortices in four monkeys trained to remain motionless in a primate chair. The use of an optical recording technique (NIRS) allows measurement of a signal that is physiologically equivalent to that obtained using BOLD fMRI, though with millisecond temporal resolution and minimal technical or environmental constraints. The different signal types exhibited correlations between the two regions of interest in both the frequency and time domains. This evidence suggests that the resting-state network activations detected by fMRI do in fact reflect functional coactivations of areas across multiple levels of network communication

Finite Sample Properties of the QMLE for the Log-ACD Model: Application to Australian Stocks

This paper is concerned with the finite sample properties of the Quasi Maximum Likelihood Estimator (QMLE) of the Logarithmic Autoregressive Conditional Duration (Log-ACD) model. Although the distribution of the QMLE for the log-ACD model is unknown, it is an important issue as it is used widely for testing various market microstructure models and effects. Knowledge of the distribution of the QMLE is crucial for purposes of valid inference and diagnostic checking. This paper investigates the structural and statistical properties of the log-ACD model by establishing the relationship between the log-ACD model and the Autoregressive-Moving Average (ARMA) model. The theoretical results developed in the paper are evaluated using Monte Carlo experiments. The experimental results also provide insights into the finite sample properties of the log-ACD model under different distributional assumptions.Conditional duration, Asymmetry, ACD, Log-ACD, Monte Carlo simulation Acknowledgement: The authors are grateful for the financial support of the Australian Research Council.

Functional differentiation within the monkey cortex as revealed by near-infrared spectroscopy

The role of prefrontal cortex in working memory (WM) is well established. However, questions remain regarding the topography and “domain-specific differentiation” of different types of information processing in the cortex. While it has been theorized that dorsolateral (DPFC) and ventrolateral (VPFC) prefrontal cortex preferentially process spatial and object WM, respectively, both electrophysiological evidence in the monkey and neuroimaging in the human have largely failed to demonstrate such regional differentiation. In this study we use near-infrared spectroscopy (NIRS) to detect functional changes, across relatively large cortical cell populations, simultaneously from prefrontal and posterior parietal cortices. Imaging data were recorded from a Rhesus macaque performing two types of WM tasks: a spatial task in which the animal had to retain the spatial position of a visual stimulus, and a non-spatial task where he had to retain its color (red or green) during a 20s delay. During performance of the spatial WM task, cerebral activation trends were found in which DPFC exhibited stronger activation than did the VPFC, and posterior parietal cortex maintained higher delay activation than did frontal regions. These differences were less pronounced during performance of the non-spatial task. Additionally, incorrect trials generally elicited lower activations during the delay period than did trials ending with a correct response. Furthermore, NIRS data collected during the performance of a haptic WM task also appear to exhibit inter-regional differences in delay activation. The data thus suggest the presence of preferential cognitive processing between and within posterior and frontal cortical regions

Interaction Between Knowledge Management Practices, Innovation and Job Creation in the Niger Delta Development Commission (NDDC), Nigeria

Knowledge and its management are essential tools for job creation, economic growth, and development. Despite its importance, not many organizations are making adequate use of their knowledge assets. The current study examined the influence of knowledge management practices and innovation on job creation in the Niger Delta Development Commission (NDDC), Nigeria. The study adopted the survey research design. 440 out of the population of 879 employees of the commission was used for the study. Data analysis was done using descriptive and inferential statistics such as percentage distribution, mean and standard deviation as well as regression analysis. The findings revealed an overall moderate extent of job creation in the Niger Delta region of Nigeria, it indicates a high extent of knowledge management practices, it shows a high extent of innovation management practices. The study concluded that knowledge management processes were a significant predictor of job creation in the region (Adjusted R2 =.413, F (1, 306) = 217.418, P < .05). It was recommended that authority of the Niger Delta Development Commission (NDDC) should strive to maintain their level of knowledge and innovation management practices with a view to improving employment generation and general development of the area. Keywords: Knowledge management, Practices, Innovation, Job creation DOI: 10.7176/IKM/9-2-0

Towards an Interaction-Centered and Dynamically Constructed Episodic Memory for Social Robots

Hassan T, Kopp S. Towards an Interaction-Centered and Dynamically Constructed Episodic Memory for Social Robots. In: Companion of the 2020 ACM/IEEE International Conference on Human-Robot Interaction (HRI ’20 Companion). New York: ACM; 2020.This paper outlines an interaction-centered and dynamically constructed episodic memory for social robots, in order to enable naturalistic, social human-robot interaction. The proposed model includes a record of multi-timescale events stored in the event history, a record of multi-timescale interval definitions stored as interaction episodes, and a set of links associating specific elements of the two records. The event history is constructed dynamically, depending on the occurrence of internal and external events. The interaction episodes are defined on the basis of robot-initiated and user-initiated interactions. The episodic memory is realised within a social human-robot interaction architecture, whose components generate events pertaining to the context and state of interaction

Fast Variability of Nonthermal X-Ray Emission in Cassiopeia A: Probing Electron Acceleration in Reverse-Shocked Ejecta

Recent discovery of the year-scale variability in the synchrotron X-ray emission of the supernova remnant (SNR) RX J1713.7-3946 has initiated our study of multi-epoch X-ray images and spectra of the young SNR Cassiopeia A based on the Chandra archive data taken in 2000, 2002, and 2004. We have found year-scale time variations in the X-ray intensity for a number of X-ray filaments or knots associated with the reverse-shocked regions. The X-ray spectra of the variable filaments are characterized by a featureless continuum, and described by a power law with a photon index within 1.9-2.3. The upper limits on the iron K-line equivalent width are 110 eV, which favors a synchrotron origin of the X-ray emission. The characteristic variability timescale of 4 yr can be explained by the effects of fast synchrotron cooling and diffusive shock acceleration with a plausible magnetic field of 1 mG. The X-ray variability provides a new effective way of studying particle acceleration at supernova shocks.Comment: 4 pages, 4 figures, accepted for publication in ApJ Lette

Sustainability and life cycle assessment (LCA) of macroalgae-derived single cell oils

Marine macroalgae (seaweed) has many advantages over terrestrial crops as a source of renewable biomass but is severely underutilised at present, especially within Europe. In particular, macroalgae has elevated poly- and monosaccharide content, making it an ideal feedstock as a heterotrophic fermentation sugar source for the production of higher value chemicals. Recent reports have detailed the suitability of seaweeds as a feedstock for the production of single-cell oils (SCOs) which have application in food, oleochemicals and fuels. It is proposed that a biorefinery system based on the production of SCOs alongside other secondary metabolites, has the potential to provide a sustainable replacement to terrestrial oils such as palm oil. This work therefore evaluates, for the first time, the environmental and economic sustainability of a production process for SCOs from seaweed Saccharina latissima using the oleaginous yeast Metschnikowia pulcherrima. Two alternative fermentation systems were considered, and uncertainties associated with the seasonal variation in seaweed carbohydrate yield and fermentation performance were integrated into the analysis. From an environmental perspective, the work indicates that seaweed derived SCO lipids and fats can be comparable to a terrestrial oil mix, with a potential climate change impact ranging between 2.5 and 9.9 kg CO 2 eq. kg −1 refined SCO. Interestingly and of particular significance, environmental impacts are mainly dominated by energy demand within fermentation and upstream processing steps. From an economic perspective, a break-even selling price for the oil was determined as between €5,300-€31,000 tonne −1 refined SCO, which was highly dependent on cost of the seaweed feedstock. Overall, we demonstrate that key uncertainties relating to seaweed cultivation costs and hydrolysate fermentation at scale result in a large range in values for environmental impact and economic return on investment. Yet even within the constraints and limitations of current knowhow, seaweed already offers a viable proposition for the competitive production of exotic oils similar to cocoa or shea butter in price and nature. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 665992 </p

3-(2-Acetamido­phen­yl)sydnone

Sydnones are unusual mesoionic compounds containing a five-membered heterocyclic ring. Generally for stability, substitution at the N-3 position by an aromatic fragment is necessary. In the title compound, C10H9N3O3, the aromatic substitutent is 2-acetamido­phenyl. The two planar ring fragments are twisted relative to one another, with a inter­planar angle of 63.13 (5)°. The mol­ecules are packed into the unit cell via π–π inter­actions between the phenyl rings [inter­planar separation = 3.4182 (4) Å] and between the sydnone rings [inter­planar separation = 3.2095 (4) Å]. N—H⋯O and C—H⋯O hydrogen bonding is also found inter­nally and externally to the mol­ecule