What effect does network size have on NRTK positioning?

The Network Real Time Kinematic (NRTK) positioning is nowadays a very common practice not only in academia but also in the professional world. To support the users several networks of Continuous Operating Reference Stations (CORSs) were born. These networks offer real-time services for NRTK positioning, providing a centimetric positioning accuracy with an average distance of 25-35 kms between the reference stations. But what is the effective distance between reference stations that allows to achieve the precision required for real-time positioning, using both geodetic and GIS receivers? How the positional accuracy changes with increasing distances between CORS? Can a service of geostationary satellites, such as the European EGNOS, be an alternative to the network positioning for medium-low cost receivers? These are only some of the questions that the Authors try to answer in this articl

Earthquake forecasting: a possible solution considering the GPS ionospheric delay

Abstract. The recent earthquakes in L'Aquila (Italy) and in Japan have dramatically emphasized the problem of natural disasters and their correct forecasting. One of the aims of the research community is to find a possible and reliable forecasting method, considering all the available technologies and tools. Starting from the recently developed research concerning this topic and considering that the number of GPS reference stations around the world is continuously increasing, this study is an attempt to investigate whether it is possible to use GPS data in order to enhance earthquake forecasting. In some cases, ionospheric activity level increases just before to an earthquake event and shows a different behaviour 5–10 days before the event, when the seismic event has a magnitude greater than 4–4.5 degrees. Considering the GPS data from the reference stations located around the L'Aquila area (Italy), an analysis of the daily variations of the ionospheric signal delay has been carried out in order to evaluate a possible correlation between seismic events and unexpected variations of ionospheric activities. Many different scenarios have been tested, in particular considering the elevation angles, the visibility lengths and the time of day (morning, afternoon or night) of the satellites. In this paper, the contribution of the ionospheric impact has been shown: a realistic correlation between ionospheric delay and earthquake can be seen about one week before the seismic event

Future large-scale water-Cherenkov detector

MEMPHYS (MEgaton Mass PHYSics) is a proposed large-scale water-Cherenkov experiment to be performed deep underground. It is dedicated to nucleon decay searches and the detection of neutrinos from supernovae, solar, and atmospheric neutrinos, as well as neutrinos from a future beam to measure the CP violating phase in the leptonic sector and the mass hierarchy. This paper provides an overview of the latest studies on the expected performance of MEMPHYS in view of detailed estimates of its physics reach, mainly concerning neutrino beams

Study of the performance of a large scale water-Cherenkov detector (MEMPHYS)

MEMPHYS (MEgaton Mass PHYSics) is a proposed large-scale water Cherenkov experiment to be performed deep underground. It is dedicated to nucleon decay searches, neutrinos from supernovae, solar and atmospheric neutrinos, as well as neutrinos from a future Super-Beam or Beta-Beam to measure the CP violating phase in the leptonic sector and the mass hierarchy. A full simulation of the detector has been performed to evaluate its performance for beam physics. The results are given in terms of "Migration Matrices" of reconstructed versus true neutrino energy, taking into account all the experimental effects.Comment: Updated after JCAP's referee's comment

Fat Embolism: What We Have Learned from Animal Models

Pulmonary fat embolism may not be diagnosed before unrelated autopsy and have little clinical impact or lead to acute lung injury with fulminant fat embolism syndrome (FES). The fat may come from various anatomic locations, bone marrow being the most common. There is no specific treatment. This review discusses animal models that can lead to a better understanding of pathophysiological mechanisms underlying this condition and indicates the importance of specific cellular constituents. A hypothesis is postulated that there is a vicious cycle involving oleic acid and angiotensin II (both of which are pulmonary toxicants): oleic acid is derived from lipid embolism by pulmonary lipases that are stimulated by angiotensin; oleic acid also promotes local generation of angiotensin. The potential role of fatty acid receptors and the resolution of this cycle are discussed. Studies show there is potential for long-term effects that might not be revealed in the immediate post-recovery period. Evidence is reviewed that animals are vulnerable to “second hit” effects at a time remote from the initial event. Some beneficial pharmacological treatments are described. These include different drugs acting on the renin-angiotensin system (RAS) that could eventually serve alone or in combination for treatment or prevention. Future therapeutic developments are discussed

Co-existence of Antiphospholipid syndrome and Heparin-induced Thrombocytopenia in a patient with Recurrent Venous Thromboembolism.

Heparin-induced thrombocytopenia (HIT) is a prothrombotic adverse drug reaction in which heparin forms complexes with platelet factor 4 forming neoantigens that are recognized by autoantibodies. Antiphospholipid syndrome (APS) is similar to HIT in that it is mediated by autoantibodies that are also pro-thrombotic. We present a case of rare co-existence of antiphospholipid antibody syndrome and heparin-induced thrombocytopenia. Introduction Heparin-induced thrombocytopenia (HIT) is a prothrombotic adverse drug reaction in which heparin forms complexes with platelet factor 4 forming neoantigens that are recognized by autoantibodies (antiHPF4/HAPA). The Fc portions of the anti-HPF4 bind Fc receptors on platelets causing platelets activation, aggregation, release of α and dense granules and formation of procoagulants [1]. The hallmark of this is thrombocytopenia and thrombosis. HIT occurs in about 2% of all patients who receive heparin of whom about 35% develop thrombosis [2]. Antiphospholipid syndrome (APS) is similar to HIT in that it is mediated by autoantibodies that are also pro-thrombotic. Autoantibodies are generated to phospholipids or to phospholipid-binding proteins which are recognized risk-factors for thrombosis and pregnancy morbidity. Diagnosis of APS requires the elevation of at least one of the phospholipid autoantibodies and a clinical manifestation (Table 1). In this report we present a patient with recurrent venous thromboembolism despite been on full anticoagulation who was found to have concurrent HIT and APS