Analysis and Calibration of Loran-C Signals in the Lower St. Lawrence Area Using GPS

Loran-C signals along and in the Lower St. Lawrence River, namely between Québec City and the Gaspesia Peninsula on the south shore, between Québec City and Havre-Saint-Pierre on the North Shore, and between Québec City and Anticosti Island in the river, were analyzed using a mobile Loran-C coverage validation and calibration system consisting of analog and digital Loran-C receivers, differential GPS and data logging systems. The road measurements were made successively during February-March and July-August 1991 to analyse seasonal effects. The signals received from the East Coast Canada Chain (5930M, X, Y, Z) and the Northeast U.S. Chain (9960M, W, X) are discussed herein. The Field Strength and Signal to Noise Ratio measurements are compared with predicted values using various models for conductivity and atmospheric noise. The Time Difference (TD) measurements are first compared between forward and reverse runs along the road profiles to ascertain the quality and reliability of the system utilized. The differences between Winter and Summer TD measurements are then analyzed. A relatively small but significant seasonal effect is found. The GPS-derived TD distortions are compared with those derived using various models for the combined effect of the primary, secondary and additional secondary phase lags. The differences between measured and modeled distortions reaches several jis. The effect of these differences on Loran-C positions is found to reach several hundred metres in many cases. Conclusions related to the results presented herein are made, together with recommendations pertaining to the use of these results and future investigations

21st Century Crofting: Strengths and Opportunities for Community Development

Scotland has one of the most uneven land ownership patterns in the world. In a country of 5.2 million people, about 969 people control 60% of the land. Over 20% of privately owned land in Scotland is held in some form of offshore or beneficial ownership (Committee on the Inquiry of Crofting, 2008). This land ownership pattern has a unique expression in the northern and western parts of the Scottish Highlands and Islands with a 300-year-old system of tenant farmers known as crofters. Unlike other tenant farmers across the world, crofters have gained legal rights to stay on the land if they are productive. While crofting has managed to survive, there are competing resources for land in rural Scotland; urbanites from England and Glasgow view rural Scotland as sites for holiday homes, thus raising land prices. Further, as with other places around the world, market forces in Scotland are merging small parcels of land into larger tracts for agriculture. This qualitative case study examines crofting on an island off the western coast of Scotland. Our primary research question is: Is there a sense of solidarity among residents about crofting for the island\u27s economic vitality and its role in sustaining or preserving local culture

Sodium channel expression in the ventral posterolateral nucleus of the thalamus after peripheral nerve injury

Peripheral nerve injury is known to up-regulate the expression of rapidly-repriming Nav1.3 sodium channel within first-order dorsal root ganglion neurons and second-order dorsal horn nociceptive neurons, but it is not known if pain-processing neurons higher along the neuraxis also undergo changes in sodium channel expression. In this study, we hypothesized that after peripheral nerve injury, third-order neurons in the ventral posterolateral (VPL) nucleus of the thalamus undergo changes in expression of sodium channels. To test this hypothesis, adult male Sprague-Dawley rats underwent chronic constriction injury (CCI) of the sciatic nerve. Ten days after CCI, when allodynia and hyperalgesia were evident, in situ hybridization and immunocytochemical analysis revealed up-regulation of Nav1.3 mRNA, but no changes in expression of Nav1.1, Nav1.2, or Nav1.6 in VPL neurons, and unit recordings demonstrated increased background firing, which persisted after spinal cord transection, and evoked hyperresponsiveness to peripheral stimuli. These results demonstrate that injury to the peripheral nervous system induces alterations in sodium channel expression within higher-order VPL neurons, and suggest that misexpression of the Nav1.3 sodium channel increases the excitability of VPL neurons injury, contributing to neuropathic pain

Student Educational Responsibility: ACase Study of Emotional Response to International Education

This study focuses on student emotional reactions toward new events or stimuli within a learner-centered, international education course. Using the primary tenets of appraisal theory, researchers analyzed novel stimuli, as identified by the students, and students’ emotional reactions toward each stimulus. Participants were immersed into two separate Scottish island communities for a 22-day period. The primary course objective included students developing leadership skills associated with community development while working with ruralScottish communities.Results indicated that students experienced a wide range of emotions associated with multiple stimuli. Identified stimuli were dichotomized into two categories, the international immersion process as well as the shift in educational responsibility from instructor to student. Emotional magnitude and coping mechanisms differed from student to student. Post international study reflections indicated that students experienced a deeper learning experience when using a learner-centered approach to international education

Multiple wavelength vertical-cavity surface-emitting laser arrays using surface-controlled MOCVD growth rate enhancement and reduction

Multiple-wavelength VCSEL and photodetector arrays are useful for wavelength-multiplexed fiberoptic networks, and for optical crosstalk isolation in parallel, free-space interconnects. Multiple wavelength VCSEL arrays have been obtained by varying the growth rate using thermal gradients caused by a backside-patterned substrate, by growth enhancement on a patterned substrate, and by varying the cavity length through anodic oxidation and selective etching of the wafer. We show here for the first time both the enhancement and the reduction of the growth rate of the entire VCSEL structure on a topographically patterned substrate, and demonstrate the controlled variation of the lasing wavelengths of a VCSEL array over an extended spectral range

Deconstructing the Big Valley Search Space Hypothesis

The big valley hypothesis suggests that, in combinatorial optimisation, local optima of good quality are clustered and surround the global optimum. We show here that the idea of a single valley does not always hold. Instead the big valley seems to de-construct into several valleys, also called ‘funnels’ in theoretical chemistry. We use the local optima networks model and propose an effective procedure for extracting the network data. We conduct a detailed study on four selected TSP instances of moderate size and observe that the big valley decomposes into a number of sub-valleys of different sizes and fitness distributions. Sometimes the global optimum is located in the largest valley, which suggests an easy to search landscape, but this is not generally the case. The global optimum might be located in a small valley, which offers a clear and visual explanation of the increased search difficulty in these cases. Our study opens up new possibilities for analysing and visualising combinatorial landscapes as complex networks

Are voltage-gated sodium channels on the dorsal root ganglion involved in the development of neuropathic pain?

Neuropathic pain is a common clinical condition. Current treatments are often inadequate, ineffective, or produce potentially severe adverse effects. Understanding the mechanisms that underlie the development and maintenance of neuropathic pain will be helpful in identifying new therapeutic targets and developing effective strategies for the prevention and/or treatment of this disorder. The genesis of neuropathic pain is reliant, at least in part, on abnormal spontaneous activity within sensory neurons. Therefore, voltage-gated sodium channels, which are essential for the generation and conduction of action potentials, are potential targets for treating neuropathic pain. However, preclinical studies have shown unexpected results because most pain-associated voltage-gated channels in the dorsal root ganglion are down-regulated after peripheral nerve injury. The role of dorsal root ganglion voltage-gated channels in neuropathic pain is still unclear. In this report, we describe the expression and distribution of voltage-gated sodium channels in the dorsal root ganglion. We also review evidence regarding changes in their expression under neuropathic pain conditions and their roles in behavioral responses in a variety of neuropathic pain models. We finally discuss their potential involvement in neuropathic pain

Coarse-Grained Barrier Trees of Fitness Landscapes

Recent literature suggests that local optima in fitness landscapes are clustered, which offers an explanation of why perturbation-based metaheuristics often fail to find the global optimum: they become trapped in a sub-optimal cluster. We introduce a method to extract and visualize the global organization of these clusters in form of a barrier tree. Barrier trees have been used to visualize the barriers between local optima basins in fitness landscapes. Our method computes a more coarsely grained tree to reveal the barriers between clusters of local optima. The core element is a new variant of the flooding algorithm, applicable to local optima networks, a compressed representation of fitness landscapes. To identify the clusters, we apply a community detection algorithm. A sample of 200 NK fitness landscapes suggests that the depth of their coarse-grained barrier tree is related to their search difficulty

Techniques for accurate protein identification in shotgun proteomic studies of human, mouse, bovine, and chicken lenses

Analysis of shotgun proteomics datasets requires techniques to distinguish correct peptide identifications from incorrect identifications, such as linear discriminant functions and target/decoy protein databases. We report an efficient, flexible proteomic analysis workflow pipeline that implements these techniques to control both peptide and protein false discovery rates. We demonstrate its performance by analyzing two-dimensional liquid chromatography separations of lens proteins from human, mouse, bovine, and chicken lenses. We compared the use of International Protein Index databases to UniProt databases and no-enzyme SEQUEST searches to tryptic searches. Sequences present in the International Protein Index databases allowed detection of several novel crystallins. An alternate start codon isoform of βA4 was found in human lens. The minor crystallin γN was detected for the first time in bovine and chicken lenses. Chicken γS was identified and is the first member of the γ-crystallin family observed in avian lenses