A New Differential Positioning Method using Modulation Correlation of Signals of Opportunity

Global Navigation Satellite Systems (GNSS) have become the positioning systems of choice for many applications. However, GNSS signals are susceptible to obstruction, interference and jamming. Therefore, to maximize robustness and integrity, it is necessary to employ a dissimilar positioning technology that can operate independently and back-up GNSS. One such technology exploits 'signals of opportunity' - signals that are designed for purposes other than navigation.This paper presents a system that uses amplitude modulation (AM) radio broadcasts in the medium frequency (MF) band. At these frequencies, the predominant ground-wave propagation mode offers better coverage in remote areas and over sea than is achievable with higher frequency signals.The system is differential and operates by correlating modulation information between the reference and user receivers. A system of this form mitigates the deterioration in and around buildings encountered in prior systems and can provide absolute position using fewer signals than a system using only carrier phase.The system presented in this paper uses generalized cross correlation to obtain time difference of arrival measurements that are subsequently used for position determination. Preliminary results indicate the system provides a robust position solution. Moreover, the system offers the potential to be combined with carrier phase measurements to achieve enhanced performance, while the modulation correlation technique is readily extendable to other types of signal

A Differential Positioning System Using Modulation Correlation of Signals of Opportunity

Global Navigation Satellite Systems (GNSS) have become the positioning systems of choice for many applications. However, GNSS signals are susceptible to obstruction, interference and jamming. Therefore, to maximize robustness and integrity, it is necessary to employ a dissimilar positioning technology that can operate independently and back-up GNSS. One such technology exploits ‘signals of opportunity’ – signals that are designed for purposes other than navigation. This paper presents a system that uses amplitude modulation (AM) radio broadcasts in the medium frequency (MF) band. At these frequencies, the predominant ground-wave propagation mode offers better coverage in remote areas and over sea than is achievable with higher frequency signals. The system is differential and operates by correlating modulation information between the reference and user receivers. A system of this form mitigates the deterioration in and around buildings encountered in prior systems and can provide absolute position using fewer signals than a system using only carrier phase. The system presented in this paper uses generalized cross correlation to obtain time difference of arrival measurements that are subsequently used for position determination. Preliminary results indicate the system provides a robust position solution. Moreover, the system offers the potential to be combined with carrier phase measurements to achieve enhanced performance, while the modulation correlation technique is readily extendable to other types of signal

Acute stress selectively impairs learning to act

Stress interferes with instrumental learning. However, choice is also influenced by non-instrumental factors, most strikingly by biases arising from Pavlovian associations that facilitate action in pursuit of rewards and inaction in the face of punishment. Whether stress impacts on instrumental learning via these Pavlovian associations is unknown. Here, in a task where valence (reward or punishment) and action (go or no-go) were orthogonalised, we asked whether the impact of stress on learning was action or valence specific. We exposed 60 human participants either to stress (socially-evaluated cold pressor test) or a control condition (room temperature water). We contrasted two hypotheses: that stress would lead to a non-selective increase in the expression of Pavlovian biases; or that stress, as an aversive state, might specifically impact action production due to the Pavlovian linkage between inaction and aversive states. We found support for the second of these hypotheses. Stress specifically impaired learning to produce an action, irrespective of the valence of the outcome, an effect consistent with a Pavlovian linkage between punishment and inaction. This deficit in action-learning was also reflected in pupillary responses; stressed individuals showed attenuated pupillary responses to action, hinting at a noradrenergic contribution to impaired action-learning under stress

The Pigna Barney Ophiolitic Complex and Associated Basaltic Rocks, Northeastern New South Wales, Australia

The Pigna Barney Ophiolitic Complex (PBOC) is a lithologically and chemically distinctive ultramafic-mafic melange which is largely confined to major fault zones in the Pigna Barney-Curricabark area, southern New England Orogen (NEO), northeastern New South Wales. For the most part, the PBOC lies along the arcuate, southern-most section of the Peel Fault System. This major steeply-dipping fault system marks the line of contact between a complex accretionary terrane (Zone B) lying to the east and north, and a significantly less-deformed volcanic arcrelated basin (Tamworth Belt) lying to the west and south. Fragments of the PBOC also lie within Zone B, especially along the Curricabark Fault Zone and along faulted contacts between the? pre-Devonian, largely hemipelagic Myra beds and Permian epiclastics of the Nambucca Association. The PBOC is everywhere in contact with adjacent stratigraphic associations, and non-tectonic contacts between its various component lithologies are exceedingly rare. The PBOC consists of: (i) a highly disrupted and incompletely preserved ophiolitic assemblage whose members consistently display atypically low abundances of "incompatible" elements (e.g. Ti, Zr, P); and (ii) a diverse range of igneous, sedimentary and metamorphic lithologies which generally occur as tectonic blocks in serpentinite-matrix melange (highly sheared tectonized harzburgite). In its type area the PBOC displays a crude internal ophiolitic stratigraphy which, at least on present orientation, consistently faces the Tamworth Belt to the southwest. Seven distinct lithological groups comprise the ophiolitic members of the PBOC. All groups are altered to varying degrees. In order of general structural position and inferred stratigraphic sequence these groups are: (1) depleted tectonized harzburgite - Fo92-91,Al₂0

Primary liver cancer in the UK: Incidence, incidence-based mortality, and survival by subtype, sex, and nation

Background & Aims: The incidence of primary liver cancer (PLC) is increasing in Western Europe. To understand trends over time and the current burden in the UK, a detailed analysis of the epidemiology of PLC and its subtypes was conducted. Methods: Data on PLCs diagnosed during 1997-2017 were obtained from population-based, nationwide registries in the UK. European age-standardised incidence (ASR) and incidence-based mortality rates (ASMR) per 100,000 person-years were calculated overall and by sex and UK-nation. Annual percentage change in rates was estimated using Joinpoint regression. One-, 2-, and 5-year age-standardised net survival was estimated. Results: A total of 82,024 PLCs were diagnosed. Both hepatocellular carcinoma (HCC) incidence and mortality rates trebled (ASR 1.8-5.5 per 100,000, ASMR 1.3-4.0). The rate of increase appeared to plateau around 2014/2015. Scottish men consistently had the highest HCC incidence rates. PLC survival increased, driven by a substantial increase in the proportion that are HCC (as prognosis is better than other PLCs) and in HCC survival (change in 1-year survival 24-47%). Intrahepatic cholangiocarcinoma was the most common PLC in women and 1-year survival improved from 22.6% to 30.5%. Conclusions: PLC incidence has been increasing rapidly but, as most risk factors are modifiable, it is largely a preventable cancer. This rate of increase has slowed in recent years, possibly attributable to effective treatment for hepatitis C. As other risk factors such as obesity and diabetes remain prevalent in the UK, it is unlikely the considerable burden of this disease will abate. While improvements in survival have been made, over half of patients are not alive after 1 year, therefore further progress in prevention, early detection, and treatment innovation are needed. Lay summary: Many more people are getting liver cancer, particularly the subtype hepatocellular carcinoma, than 20 years ago. Men in Scotland are most likely to get liver cancer and to die from it. Survival after liver cancer diagnosis is getting longer but still less than half are alive after 1 year

Trim17, novel E3 ubiquitin-ligase, initiates neuronal apoptosis

Accumulating data indicate that the ubiquitin-proteasome system controls apoptosis by regulating the level and the function of key regulatory proteins. In this study, we identified Trim17, a member of the TRIM/RBCC protein family, as one of the critical E3 ubiquitin ligases involved in the control of neuronal apoptosis upstream of mitochondria. We show that expression of Trim17 is increased both at the mRNA and protein level in several in vitro models of transcription-dependent neuronal apoptosis. Expression of Trim17 is controlled by the PI3K/Akt/GSK3 pathway in cerebellar granule neurons (CGN). Moreover, the Trim17 protein is expressed in vivo, in apoptotic neurons that naturally die during post-natal cerebellar development. Overexpression of active Trim17 in primary CGN was sufficient to induce the intrinsic pathway of apoptosis in survival conditions. This pro-apoptotic effect was abolished in Bax(-/-) neurons and depended on the E3 activity of Trim17 conferred by its RING domain. Furthermore, knock-down of endogenous Trim17 and overexpression of dominant-negative mutants of Trim17 blocked trophic factor withdrawal-induced apoptosis both in CGN and in sympathetic neurons. Collectively, our data are the first to assign a cellular function to Trim17 by showing that its E3 activity is both necessary and sufficient for the initiation of neuronal apoptosis. Cell Death and Differentiation (2010) 17, 1928-1941; doi: 10.1038/cdd.2010.73; published online 18 June 201

Epileptogenic Tubers Are Associated with Increased Kurtosis of Susceptibility Values: A Combined Quantitative Susceptibility Mapping and Stereoelectroencephalography Pilot Study

BACKGROUND AND PURPOSE: Prior studies have found an association between calcification and the epileptogenicity of tubers in tuberous sclerosis complex. Quantitative susceptibility mapping is a novel tool sensitive to magnetic susceptibility alterations due to tissue calcification. We assessed the utility of quantitative susceptibility mapping in identifying putative epileptogenic tubers in tuberous sclerosis complex using stereoelectroencephalography data as ground truth. MATERIALS AND METHODS: We studied patients with tuberous sclerosis complex undergoing stereoelectroencephalography at a single center who had multiecho gradient-echo sequences available. Quantitative susceptibility mapping and R2* values were extracted for all tubers on the basis of manually drawn 3D ROIs using T1- and T2-FLAIR sequences. Characteristics of quantitative susceptibility mapping and R2* distributions from implanted tubers were compared using binary logistic generalized estimating equation models designed to identify ictal (involved in seizure onset) and interictal (persistent interictal epileptiform activity) tubers. These models were then applied to the unimplanted tubers to identify potential ictal and interictal tubers that were not sampled by stereoelectroencephalography. RESULTS: A total of 146 tubers were identified in 10 patients, 76 of which were sampled using stereoelectroencephalography. Increased kurtosis of the tuber quantitative susceptibility mapping values was associated with epileptogenicity (P = .04 for the ictal group and P = .005 for the interictal group) by the generalized estimating equation model. Both groups had poor sensitivity (35.0% and 44.1%, respectively) but high specificity (94.6% and 78.6%, respectively). CONCLUSIONS: Our finding of increased kurtosis of quantitative susceptibility mapping values (heavy-tailed distribution) was highly specific, suggesting that it may be a useful biomarker to identify putative epileptogenic tubers in tuberous sclerosis complex. This finding motivates the investigation of underlying tuber mineralization and other properties driving kurtosis changes in quantitative susceptibility mapping values

Kinesin expands and stabilizes the GDP-microtubule lattice

Kinesin-1 is a nanoscale molecular motor that walks towards the fast-growing (plus) ends of microtubules, hauling molecular cargo to specific reaction sites in cells. Kinesin-driven transport is central to the self-organization of eukaryotic cells and shows great promise as a tool for nano-engineering1. Recent work hints that kinesin may also play a role in modulating the stability of its microtubule track, both in vitro2,3 and in vivo4, but the results are conflicting5,6,7 and the mechanisms are unclear. Here, we report a new dimension to the kinesin–microtubule interaction, whereby strong-binding state (adenosine triphosphate (ATP)-bound and apo) kinesin-1 motor domains inhibit the shrinkage of guanosine diphosphate (GDP) microtubules by up to two orders of magnitude and expand their lattice spacing by ~1.6%. Our data reveal an unexpected mechanism by which the mechanochemical cycles of kinesin and tubulin interlock, and so allow motile kinesins to influence the structure, stability and mechanics of their microtubule track