129 research outputs found

    Climatology of ionospheric slab thickness

    Get PDF
    The ionospheric slab thickness τ defined as a ratio of the total electron content (TEC) to the F-region peak electron density (<i>Nm</i>F2) has been analysed during the solar maximum (1981) and minimum (1985) phases of an intense, the 21st, solar cycle. Hourly values of TEC and <i>Nm</i>F2 collected at Hawaii (low-latitude), Boulder (mid-latitude) and Goosebay (high-latitude) are used in the study. Climatology of the slab thickness is described by the diurnal, seasonal, solar and magnetic activity variations of τ for the different latitude zones. It is found that, for magnetically quiet days of solar maximum, increased ionization of <i>Nm</i>F2 and TEC during the daytime is accompanied by an increased thickness of the ionosphere compared to the night-time for non-auroral latitudes. However, the reverse is found to be true during the solar minimum compensating TEC against a weak night-time ionization of <i>Nm</i>F2. For the high-latitude the night-time slab thickness is higher compared to the daytime for both the solar phases. Ratios of daily peak to minimum values of slab thickness vary from 1.3 to 3.75 with the peaks of τ often observed at pre-sunrise and post-sunset hours. The average night-to-day ratios of τ vary from 0.68 to 2.23. The day-to-day variability of τ, expressed in percentage standard deviation, varies from 10% by day (equinox, high-latitude) to 67% by night (summer, mid-latitude) during solar minimum and from 10% by day (winter and equinox, mid-latitude) to 56% by night (equinox, high-latitude) during solar maximum. A comprehensive review of slab thickness related literature is given in the paper. <br><br><b>Key words.</b> Ionospheric physic

    Derivation of a planetary ionospheric storm index

    Get PDF

    Climatology of ionospheric slab thickness

    Get PDF

    COST 296 scientific results designed for operational use

    Get PDF
    The main objective of the COST 296 Action «Mitigation of Ionospheric Effects on Radio Systems» is the establishment/ improvement of ionospheric services by coordinating the development of specific algorithms, models, and tools capable of operating in a near-real-time mode. Key elements of these activities are contributions related to monitoring, modelling, and imaging of customer-relevant ionospheric quantities. COST stimulates, coordinates, and supports Europe’s goals of development and global cooperation by providing high quality information and knowledge of ionospheric and plasmaspheric conditions enabling high quality and reliable operation of radio systems. It also provides a platform for sharing such tools as algorithms or models, and for the joint development of advanced technologies. It takes advantage of many national and European service initiatives, for example DIAS (http://dias.space.noa.gr), SWACI (http://w3swaci.dlr.de), ESWUA (http://www.eswua.ingv.it/ingv), RWC-Warsaw (http://www.cbk.waw.pl/rwc), the COST Prompt Ionospheric Database http://www.wdc.rl.ac.uk/cgibin/ digisondes/cost_database.pl, http://www.izmiran.ru/services, and others. Existing national capabilities are taken into account to develop synergies and avoid duplication. The enhancement of environment monitoring networks and associated instrumentation yields mutual advantages for European and regional services specialized for local user needs. It structurally increases the integration of limited-area services, and generates a platform employing the same approach to each task differing mostly in input and output data. In doing so it also provides a complementary description of the environmental state within issued information, as well as providing a platform for interaction among local end users, who define what kind of information they need, for system providers, who finalize the tools necessary to obtain required information, and for local service providers, who do the actual processing of data, tailoring it to specific users’ needs. Such an initiative creates a unique opportunity for small national services to consolidate their product design so that is no longer limited to their own activity, but can serve the wider European services. The development and improvement of techniques for mitigating ionospheric effects on radio systems by the COST 296 Action prepared those services that implemented the new design techniques for the newly announced EU and ESA policy-Space Situation Awareness (SSA). COST 296 developments applied to nowcasting and forecasting services are an essential input to the Operational SSA Ionosphere

    Tissue-specific effects of benzo[a]pyrene and DDT on microRNA expression profile in female rats

    Get PDF
    Many xenobiotics in the human environment, such as benzo[a]pyrene (B(a)P) and dichlorodiphenyltrichloroethane (DDT), may act as non-genotoxic carcinogens through epigenetic mechanisms, including changes in microRNA expression profile. In part, such disorders can be mediated by the activation of nuclear receptors, resulting in the activation of protein coding gene expression and microRNAs involved in malignant transformation of cells. Therefore, the aim of this study was to investigate the chain of events “xenobiotic administration – receptor activation – up-regulating microRNA expression – down-regulation target genes expression” as one of the key factors in the chemically-induced carcinogenesis. Using in silico methods, an analysis of the rat genome was carried out to find microRNAs putatively regulated by AhR (aryl hydrocarbon receptor) and CAR (constitutive androstane receptor), activated by BP and DDT, respectively. In particular, miR-3577 and -193b were selected as potentially regulated CAR, miR-207 was selected as a candidate for miR under AhR regulation. The results of the study showed that the treatment of female rats with DDT and B(a)P caused a tissue-specific changes in the expression of microRNAs and host genes in both acute and chronic administration of xenobiotics. To confirm the effects of xenobiotics on the microRNA expression, we also estimated the mRNA level of PTPN6, EIF3F, Cbx7, and Dicer1 genes potentially targeting miR-193b, -207, and -3577. The study has shown a high correlation between the expression of target genes and microRNAs; however these changes depended on the tissue types, the dose and time after xenobiotic treatment

    Near Earth space plasma monitoring under COST 296

    Get PDF
    This review paper presents the main achievements of the near Earth space plasma monitoring under COST 296 Action. The outputs of the COST 296 community making data, historical and real-time, standardized and available to the ionospheric community for their research, applications and modeling purposes are presented. The contribution of COST 296 with the added value of the validated data made possible a trusted ionospheric monitoring for research and modeling purposes, and it served for testing and improving the algorithms producing real-time data and providing data users measurement uncertainties. These value added data also served for calibration and validation of space-borne sensors. New techniques and parameters have been developed for monitoring the near Earth space plasma, as time dependent 2D maps of vertical total electron content (vTEC), other key ionospheric parameters and activity indices for distinguishing disturbed ionospheric conditions, as well as a technique for improving the discrepancies of different mapping services. The dissemination of the above products has been developed by COST 296 participants throughout the websites making them available on-line for real-time applications

    MicroRNA level in patients with stable coronary artery disease with borderline coronary artery stenosis

    Get PDF
    Aim. To assess the level of microRNA (miR) -21, -22, -126, -221 in patients with coronary artery disease (CAD) with borderline coronary artery stenosis depending on comorbidities and sex.Material and methods. We examined 37 patients with class 1-3 stable CAD aged 49-59 years with borderline (40-70%) coronary artery stenosis. The relative level of miRNA was determined using real-time polymerase chain reaction. Statistical analysis was performed using the non-parametric Mann-Whitney U-test. P<0,05 were considered statistically significant. Results. The miR-221 level was higher in the group of patients with stable CAD with borderline coronary artery stenosis with a metabolically unhealthy obesity (MUO) phenotype, but without diabetes (p=0,042). The level of miR-22 and miR-126 was higher in the group of patients with stable CAD phenotype with borderline stenosis and diabetes (p=0,007 and p=0,034, respectively). The analysis of miR levels in stable CAD patients depending on sex, without taking into account the phenotype, found that miR-21 and miR-221 values were higher in men (p=0,021 and p=0,014, respectively). The study of the sex characteristics of miR content in relation to different phenotypes revealed an increase of miR22 levels in men with MUO and diabetes (p=0,048) and an increase of miR-126 levels in women with concomitant diabetes in the comparison both with patients without MUO and diabetes (p=0,018), as well as with MUO and without diabetes (p=0,007). Conclusion. The study of the miRNA level in patients with CAD with borderline coronary artery stenosis is of great interest and reflects a promising direction in diagnosis based on comorbid pathology. Keywords: miRNA, obesity phenotypes, coronary artery disease, borderline coronary artery stenosis. Relationships and Activities: none. 1Novosibirsk State Medical University, Novosibirsk; 2Federal Research Center of Fundamental and Translational Medicine, Novosibirsk; 3E.N. Meshalkin National Medical Research Center, Novosibirsk, Russia.><0,05 were considered statistically significant.Results. The miR-221 level was higher in the group of patients with stable CAD with borderline coronary artery stenosis with a metabolically unhealthy obesity (MUO) phenotype, but without diabetes (p=0,042). The level of miR-22 and miR-126 was higher in the group of patients with stable CAD phenotype with borderline stenosis and diabetes (p=0,007 and p=0,034, respectively). The analysis of miR levels in stable CAD patients depending on sex, without taking into account the phenotype, found that miR-21 and miR-221 values were higher in men (p=0,021 and p=0,014, respectively). The study of the sex characteristics of miR content in relation to different phenotypes revealed an increase of miR22 levels in men with MUO and diabetes (p=0,048) and an increase of miR-126 levels in women with concomitant diabetes in the comparison both with patients without MUO and diabetes (p=0,018), as well as with MUO and without diabetes (p=0,007).Conclusion. The study of the miRNA level in patients with CAD with borderline coronary artery stenosis is of great interest and reflects a promising direction in diagnosis based on comorbid pathology

    SND@LHC: The Scattering and Neutrino Detector at the LHC

    Get PDF
    SND@LHC is a compact and stand-alone experiment designed to perform measurements with neutrinos produced at the LHC in the pseudo-rapidity region of 7.2<η<8.4{7.2 < \eta < 8.4}. The experiment is located 480 m downstream of the ATLAS interaction point, in the TI18 tunnel. The detector is composed of a hybrid system based on an 830 kg target made of tungsten plates, interleaved with emulsion and electronic trackers, also acting as an electromagnetic calorimeter, and followed by a hadronic calorimeter and a muon identification system. The detector is able to distinguish interactions of all three neutrino flavours, which allows probing the physics of heavy flavour production at the LHC in the very forward region. This region is of particular interest for future circular colliders and for very high energy astrophysical neutrino experiments. The detector is also able to search for the scattering of Feebly Interacting Particles. In its first phase, the detector will operate throughout LHC Run 3 and collect a total of 250 fb1\text{fb}^{-1}
    corecore