A new adaptive colorization filter for video decompression

HD content is more in demand and requires a lot of bandwidth. In this paper, a new real-time adaptive colorization filter for HD videos is presented. This approach reduces the required bandwidth by reducing non-key frames in the HD video sequence to grayscale and colourizing these frames at the decompression stage. Additionally this technique determines the frame status based on the image information

Analysing and modelling train driver performance

Arguments for the importance of contextual factors in understanding human performance have been made extremely persuasive in the context of the process control industries. This paper puts these arguments into the context of the train driving task, drawing on an extensive analysis of driver performance with the Automatic Warning System (AWS). The paper summarises a number of constructs from applied psychological research which are thought to be important in understanding train driver performance. A “Situational Model” is offered as a framework for investigating driver performance. The model emphasises the importance of understanding the state of driver cognition at a specific time (“Now”) in a specific situation and a specific context

Local lung hypoxia determines epithelial fate decisions during alveolar regeneration.

After influenza infection, lineage-negative epithelial progenitors (LNEPs) exhibit a binary response to reconstitute epithelial barriers: activating a Notch-dependent ΔNp63/cytokeratin 5 (Krt5) remodelling program or differentiating into alveolar type II cells (AEC2s). Here we show that local lung hypoxia, through hypoxia-inducible factor (HIF1α), drives Notch signalling and Krt5pos basal-like cell expansion. Single-cell transcriptional profiling of human AEC2s from fibrotic lungs revealed a hypoxic subpopulation with activated Notch, suppressed surfactant protein C (SPC), and transdifferentiation toward a Krt5pos basal-like state. Activated murine Krt5pos LNEPs and diseased human AEC2s upregulate strikingly similar core pathways underlying migration and squamous metaplasia. While robust, HIF1α-driven metaplasia is ultimately inferior to AEC2 reconstitution in restoring normal lung function. HIF1α deletion or enhanced Wnt/β-catenin activity in Sox2pos LNEPs blocks Notch and Krt5 activation, instead promoting rapid AEC2 differentiation and migration and improving the quality of alveolar repair

Particle-in-cell simulations of rf breakdown

Breakdown voltages of a capacitively coupled radio frequency argon discharge at 27 MHz are studied. We use a one-dimensional electrostatic PIC code to investigate the effect of changing the secondary emission properties of the electrodes on the breakdown voltage, particularly at low pd values. Simulation results are compared with the available experimental results and a satisfactory agreement is found.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

Learning-Facilitated Synaptic Plasticity at CA3 Mossy Fiber and Commissural–Associational Synapses Reveals Different Roles in Information Processing

Subregion-dependent differences in the role of the hippocampus in information processing exist. Recently, it has emerged that a special relationship exists between the expression of persistent forms of synaptic plasticity in hippocampal subregions and the encoding of different types of spatial information. Little is known about this type of information processing at CA3 synapses. We report that in freely behaving rats, long-term potentiation (LTP) is facilitated at both mossy fiber (mf)–CA3 and commissural–associational (AC)–CA3 synapses by exploration of a novel (empty) environment. Exploration of large spatial landmarks facilitates long-term depression (LTD) at mf-CA3 synapses and impairs synaptic depression at AC-CA3 synapses. Novel exploration of small environmental features does not facilitate LTD at mf synapses but facilitates persistent LTD at AC synapses. Thus, depending on the quality of the information synaptic plasticity at AC-CA3 and mf-CA3 synapses is differentially modulated. These data suggest that expression of LTP as a result of environmental change is a common property of hippocampal synapses. However, LTD at mf synapses or AC synapses may subserve distinct and separate functions within the CA3 region

Learning-Facilitated Synaptic Plasticity at CA3 Mossy Fiber and Commissural–Associational Synapses Reveals Different Roles in Information Processing

Subregion-dependent differences in the role of the hippocampus in information processing exist. Recently, it has emerged that a special relationship exists between the expression of persistent forms of synaptic plasticity in hippocampal subregions and the encoding of different types of spatial information. Little is known about this type of information processing at CA3 synapses. We report that in freely behaving rats, long-term potentiation (LTP) is facilitated at both mossy fiber (mf)–CA3 and commissural–associational (AC)–CA3 synapses by exploration of a novel (empty) environment. Exploration of large spatial landmarks facilitates long-term depression (LTD) at mf-CA3 synapses and impairs synaptic depression at AC-CA3 synapses. Novel exploration of small environmental features does not facilitate LTD at mf synapses but facilitates persistent LTD at AC synapses. Thus, depending on the quality of the information synaptic plasticity at AC-CA3 and mf-CA3 synapses is differentially modulated. These data suggest that expression of LTP as a result of environmental change is a common property of hippocampal synapses. However, LTD at mf synapses or AC synapses may subserve distinct and separate functions within the CA3 region

Frequency Facilitation at Mossy Fiber–CA3 Synapses of Freely Behaving Rats Contributes to the Induction of Persistent LTD via an Adenosine-A1 Receptor-Regulated Mechanism

Frequency facilitation (FF), comprising a rapid and multiple-fold increase in the magnitude of evoked field potentials, is elicited by low-frequency stimulation (LFS) at mossy fiber–CA3 synapses. Here, we show that in freely behaving rats, FF reliably occurs in response to 1 and 2Hz but not in response to 0.25-, 0.3-, or 0.5-Hz LFS. Strikingly, prolonged (∼600 s) FF was tightly correlated to the induction of long-term depression (LTD) in freely moving animals. Although LFS at 2 Hz elicited unstable FF and unstable LTD, application of LFS at 1 Hz elicited pronounced FF, as well as robust LTD that persisted for over 24 h. This correlation of prolonged FF with LTD was absent at stimulation frequencies that did not induce FF. The adenosine-A1 receptor appears to participate in these effects: Application of adenosine-A1, but not adenosine-A3, receptor antagonists enhanced mossy fiber synaptic transmission and occluded FF. Furthermore, adenosine-A1 receptor antagonism resulted in more stable FF at 1 or 2 Hz and elicited more potent LTD. These data support the fact that FF contributes to the enablement of long-term information storage at mossy fiber–CA3 synapses and that the adenosine-A1 receptor may regulate the thresholds for this process

The On-Orbit Performance of the Galaxy Evolution Explorer

We report the first year on-orbit performance results for the Galaxy Evolution Explorer (GALEX), a NASA Small Explorer that is performing a survey of the sky in two ultraviolet bands. The instrument comprises a 50 cm diameter modified Ritchey-Chretien telescope with a 1.25 degree field of view, selectable imaging and objective grism spectroscopic modes, and an innovative optical system with a thin-film multilayer dichroic beam splitter that enables simultaneous imaging by a pair of photon counting, microchannel plate, delay line readout detectors. Initial measurements demonstrate that GALEX is performing well, meeting its requirements for resolution, efficiency, astrometry, bandpass definition and survey sensitivity.Comment: This paper will be published as part of the Galaxy Evolution Explorer (GALEX) Astrophysical Journal Letters Special Issu