Respect for Grizzly Bears: An Aboriginal Approach for Co-existence and Resilience

Aboriginal peoples’ respect for grizzly bear (Ursus arctos) is widely acknowledged, but rarely explored, in wildlife management discourse in northern Canada. Practices of respect expressed toward bears were observed and grouped into four categories: terminology, stories, reciprocity, and ritual. In the southwest Yukon, practices in all four categories form a coherent qualitative resource management system that may enhance the resilience of the bear-human system as a whole. This system also demonstrates the possibility of a previously unrecognized human role in maintaining productive riparian ecosystems and salmon runs, potentially providing a range of valued social-ecological outcomes. Practices of respect hold promise for new strategies to manage bear-human interactions, but such successful systems may be irreducibly small scale and place based

Pulse source for 80 Gb/s systems using a gain-wwitched laser diode followed by a nonlinearly chirped grating

This work presents the generation of 3.5 ps pulses at a repetition rate of 10 GHz and the optimization of the pulse spectrum. The output pulses are near transform limited and have pulse pedestals that are virtually eliminated to 35 dB down from the peak of the pulse, thus providing a source suitable for use in 80 Gb/s OTDM systems

Optimized pulse source employing an externally injected gain-switched laser diode in conjunction with a nonlinearly chirped grating

In this paper, we demonstrate the generation of transform-limited short optical pulses, which display excellent spectral and temporal qualities by employing a novel technology, based on an externally injected gain-switched laser in conjunction with a nonlinearly chirped grating. Using this technique, 3.5-ps optical pulses exhibiting a time-bandwidth product (TBP) of 0.45 are generated, which are suitable for use in high-speed 80 Gb/s optical time-division multiplexing (OTDM) communications systems. The numerical integration of a set of rate equations using suitable parameters for the devices used in the experiments were carried out to further confirm the feasibility of the proposed method for developing an optimized pulse source for high-speed photonic systems

Systematic Analysis of Quantitative Logic Model Ensembles Predicts Drug Combination Effects on Cell Signaling Networks

A major challenge in developing anticancer therapies is determining the efficacies of drugs and their combinations in physiologically relevant microenvironments. We describe here our application of “constrained fuzzy logic” (CFL) ensemble modeling of the intracellular signaling network for predicting inhibitor treatments that reduce the phospho-levels of key transcription factors downstream of growth factors and inflammatory cytokines representative of hepatocellular carcinoma (HCC) microenvironments. We observed that the CFL models successfully predicted the effects of several kinase inhibitor combinations. Furthermore, the ensemble predictions revealed ambiguous predictions that could be traced to a specific structural feature of these models, which we resolved with dedicated experiments, finding that IL-1α activates downstream signals through TAK1 and not MEKK1 in HepG2 cells. We conclude that CFL-Q2LM (Querying Quantitative Logic Models) is a promising approach for predicting effective anticancer drug combinations in cancer-relevant microenvironments.United States. Army Research Office (W911NF-09-0001

Analysis of bit rate dependence up to 80 Gbit/s of a simple wavelength converter based on XPM in a SOA and a shifted filtering

This paper provides the analysis of wavelength converted pulses obtained with a simple semiconductor optical amplifier (SOA)-based wavelength conversion scheme, which exploits cross phase modulation (XPM) in an SOA in conjunction with shifted filtering. The analysis includes experimental measurements of the back-to-back system performances as well as frequency-resolved optical gating (FROG) characterisations of the wavelength converted pulses. These measurements are implemented at different bit rates up to 80 Gbit/s and for both red and blue-shifted filtering, particularly showing different patterning effect dependencies of red and blue-shifting techniques. This analysis is developed by the addition of a numerical study which corroborates the experimental results. A further understanding of the different performances of red and blue filtering techniques, presented in the literature, can thus be proposed. The placement of the filter to undertake red-shifted filtering (RSF) allows us to achieve very short pulse widths but high bit rate operation is limited by pattern effects. The blue-shifted filtering (BSF) technique shows optimum performance as regards to patterning effects even if the wavelength converted pulses can be larger

Signatures of Pseudoscalar Photon Mixing in CMB Radiation

We model the effect of photon and ultra-light pseudoscalar mixing on the propagation of electromagnetic radiation through the extragalactic medium. The medium is modelled as a large number of magnetic domains, uncorrelated with one another. We obtain an analytic expression for the different Stokes parameters in the limit of small mixing angle. The different Stokes parameters are found to increase linearly with the number of domains. We also verify this result by direct numerical simulations. We use this formalism to estimate the effect of pseudoscalar-photon mixing on the Cosmic Microwave Background (CMB) polarization. We impose limits on the model parameters by the CMB observations. We find that the currently allowed parameter range admits a CMB circular polarization up to order $10^{-7}$.Comment: 17 pages, 5 figure

Cell Signalling Networks in Inflammation Multi-pathway network analysis of mammalian epithelial cell responses in inflammatory environments

Abstract Inflammation is a key physiological response to infection and injury and while usually beneficial it can also be damaging to the host. The liver is a prototypical example in this regard because inflammation helps resolve liver injury but it also underlies the etiology of pathologies such as fibrosis and hepatocellular carcinoma. Cells sense their environment, including the inflammatory environment, through the activities of receptor-mediated signal transduction pathways. These pathways are organized in a complex interconnected network, and it is becoming increasingly recognized that cellular adaptations result from the quantitative integration of multi-pathway network activities, rather than isolated pathways causing particular phenotypes. Therefore, comprehending liver cell signalling in inflammation requires a scientific approach that is appropriate for studying complex networks. Here we review our application of systems analyses of liver cell signalling in response to inflammatory environments. Our studies feature broad measurements of cell signalling and phenotypes in response to numerous experimental perturbations reflective of inflammatory environments, the data from which are analyzed using Boolean and fuzzy logic models and regression-based methods in order to quantitatively relate the phenotypic responses to cell signalling network states. Our principal biological insight from these studies is that hepatocellular carcinoma cells feature uncoupled inflammatory and growth factor signalling, which may underlie their immune evasion and hyperproliferative properties. Cell Signalling Networks in Inflammatio

Multi-pathway network analysis of mammalian epithelial cell responses in inflammatory environments

Abstract Inflammation is a key physiological response to infection and injury and, although usually beneficial, it can also be damaging to the host. The liver is a prototypical example in this regard because inflammation helps to resolve liver injury, but it also underlies the aetiology of pathologies such as fibrosis and hepatocellular carcinoma. Liver cells sense their environment, including the inflammatory environment, through the activities of receptor-mediated signal transduction pathways. These pathways are organized in a complex interconnected network, and it is becoming increasingly recognized that cellular adaptations result from the quantitative integration of multi-pathway network activities, rather than isolated pathways causing particular phenotypes. Therefore comprehending liver cell signalling in inflammation requires a scientific approach that is appropriate for studying complex networks. In the present paper, we review our application of systems analyses of liver cell signalling in response to inflammatory environments. Our studies feature broad measurements of cell signalling and phenotypes in response to numerous experimental perturbations reflective of inflammatory environments, the data from which are analysed using Boolean and fuzzy logic models and regression-based methods in order to quantitatively relate the phenotypic responses to cell signalling network states. Our principal biological insight from these studies is that hepatocellular carcinoma cells feature uncoupled inflammatory and growth factor signalling, which may underlie their immune evasion and hyperproliferative properties

High Spatial Resolution X-Ray Spectroscopy of the IC443 Pulsar Wind Nebula and Environs

Deep Chandra ACIS observations of the region around the putative pulsar, CXOU J061705.3+222127, in the supernova remnant IC443 reveal an ~5$^{\prime\prime}$-radius ring-like structure surrounding the pulsar and a jet-like feature oriented roughly north-south across the ring and through the pulsar's location at 06$^{\rm h}$17$^{\rm m}$5.200$^{\rm s}$ +22$^{\circ}$21$^{\prime}$27.52$^{\prime\prime}$ (J2000.0 coordinates). The observations further confirm that (1) the spectrum and flux of the central object are consistent with a rotation-powered pulsar, (2) the non-thermal spectrum and morphology of the surrounding nebula are consistent with a pulsar wind and, (3) the spectrum at greater distances is consistent with thermal emission from the supernova remnant. The cometary shape of the nebula, suggesting motion towards the southwest, appears to be subsonic: There is no evidence either spectrally or morphologically for a bow shock or contact discontinuity; the nearly circular ring is not distorted by motion through the ambient medium; and the shape near the apex of the nebula is narrow. Comparing this observation with previous observations of the same target, we set a 99% confidence upper limit to the proper motion of CXOU J061705.3+222127 to be less than 44 mas/yr (310 km/s for a distance of 1.5 kpc), with the best-fit (but not statistically significant) projected direction toward the west.Comment: Accepted for publication in the Astrophysical Journa