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• UV-microbursts were measured by a highly sensitive photometer in auroral zone. • UV-microbursts are observed as series of pulses with complex time structure. • The relativistic electron microbursts origin of UV emission is considered. In this paper we present data on the UV-microburst (300–400 nm flashes with a duration less than 1 s) measurements in the auroral zone. Measurements were performed during the period 09.2021–04.2022 by the highly sensitive imaging photometer installed at the Verkhnetulomsky observatory of the Polar Geophysical Institute. It is shown that microbursts are grouped in a series with a duration from 10 s to 10 min. They were observed in relatively quiet geomagnetic conditions (K P < 3) at the southern boundary of the auroral oval in the evening magnetic local time (MLT) sector. UV-microbursts are observed in different observational conditions (clouds, transparent clouds and clear sky) and spatially represent various patterns: uniform diffuse illumination, local spots. Joint analyses of the optical measurements and satellite data on charged particle fluxes demonstrates that an auroral oval, characterized by a plasma, is placed to the north of the observatory. At the same time increased flux of electrons with energy more than 100 keV is observed at the same L-shell and MLT sector. The possible origin of the UV-microbursts is a precipitation of energetic electrons from a poleward boundary of the outer radiation belt in a form of relativistic electron microbursts is discussed. [ABSTRACT FROM AUTHOR]

Cancer cells are often aneuploid and frequently display elevated rates of chromosome mis-segregation, called chromosomal instability (CIN). CIN is caused by hyperstable kinetochore-microtubule (K-MT) attachments that reduce the correction efficiency of erroneous K-MT attachments. UMK57, a chemical agonist of the protein MCAK (mitotic centromere-associated kinesin), improves chromosome segregation fidelity in CIN cancer cells by destabilizing K-MT attachments, but cells rapidly develop resistance. To determine the mechanism, we performed unbiased screens, which revealed increased phosphorylation in cells adapted to UMK57 at Aurora kinase A phosphoacceptor sites on BOD1L1 (protein biorientation defective 1-like-1). BOD1L1 depletion or Aurora kinase A inhibition eliminated resistance to UMK57. BOD1L1 localizes to spindles/kinetochores during mitosis, interacts with the PP2A phosphatase, and regulates phosphorylation levels of kinetochore proteins, chromosome alignment, mitotic progression, and fidelity. Moreover, the BOD1L1 gene is mutated in a subset of human cancers, and BOD1L1 depletion reduces cell growth in combination with clinically relevant doses of Taxol or Aurora kinase A inhibitor. [Display omitted] • BOD1L1 was identified in a screen to discover the mechanism of resistance to an MCAK agonist • Aurora kinase A phosphorylates BOD1L1 to regulate PP2A activity at the kinetochore • BOD1L1 localizes to the mitotic spindle and kinetochores and regulates faithful mitosis • BOD1L1 loss increases sensitivity of cancer cells to relevant doses of Taxol Kucharski et al. identify a new signaling pathway in mitosis whereby Aurora kinase A phosphorylates BOD1L1 to increase protein phosphatase activity toward kinetochore substrates to facilitate high mitotic fidelity. This pathway provides the mechanism for adaptive resistance in cancer cells to an agonist of microtubule depolymerase. [ABSTRACT FROM AUTHOR]

Monte Carlo simulation based on Constructive Solid Geometry (CSG) brings unique challenges for multiphysics simulation, including establishing field transfers with mesh-based physics codes, the combination of stochastic and deterministic solvers, and high computational expense. In this work, an adaptive, on-the-fly mesh-based Monte Carlo geometry algorithm is implemented in Cardinal to reduce the barrier-to-entry for high-fidelity multiphysics by (i) eliminating ambiguity in defining CSG cells for temperature and density feedback, (ii) enabling simple mesh convergence studies, and (iii) more closely integrating Computer Aided Design (CAD) workflows with Monte Carlo methods. During Picard iterations, an OpenMC mesh geometry is adaptively refined or coarsened by contouring temperature and/or density fields from a thermal-fluid solver. This algorithm is applied to a full-core Molten Salt Fast Reactor (MSFR) geometry with NekRS Large Eddy Simulation (LES) coupled to OpenMC neutron transport. A performance study indicates a net speedup of 2.3 × in the OpenMC solver when using an adaptive geometry for cell sizes chosen intermediate to the as-built CAD geometry versus 1:1 element tracking, which points to future algorithmic research in accelerated Monte Carlo mesh tracking. • Adaptive unstructured mesh geometry automatically refines Monte Carlo geometry. • Large Eddy Simulation is coupled with Monte Carlo neutron transport for an MSFR. • A performance study highlights ray tracing and point containment algorithms. [ABSTRACT FROM AUTHOR]

• Ecosystem services cascade model developed for auroral ecosystem services. • Co-production is important for enabling the benefits of auroral ecosystem services. • Bridges the ecosystem service, geosystem service and exosystem service concepts. • Geophysical properties, processes and functions can be impacted by the anthroposphere. • Highlights the importance of value pluralism in future primary valuation studies. This paper serves as an initial exploration of the stages involved in the formation of auroral ecosystem services (ES) and interactions between the geosphere, biosphere and anthroposphere. This is performed through the development of an auroral ES cascade model with the integration of four main co-production stages: (i) value attribution, (ii) mobilization of ES potential, (iii) value appropriation, and (iv) commercialization. The cascade model is expanded upon in detail by using examples from published academic and grey literature, highlighting the demand for capital inputs and strengthening the conceptual understanding of human-nature relationships in the context of auroral ES. The co-production stages illustrate the importance of action on the demand-side in order for the supply of benefits from auroral ES to be delivered. The potential for feedback from the anthroposphere into geophysical properties, processes and functions through anthropogenic space weather and artificial particle precipitation from the Van Allen Radiation Belts via ionospheric heating and low frequency radio wave generation is emphasized. Additionally, feedback via policy and decision making from the anthroposphere into the biosphere and geosphere is highlighted, especially in the context of managing light pollution and artificial space weather. The discussion considers the potential implications of the expanded model, in addition to the valuation of auroral ES across three value domains (monetary, socio-cultural and biophysical) and the potential use of such information in decision-making, followed by reflecting on the potential limitations of the expanded model. [ABSTRACT FROM AUTHOR]

• First systematic review of auroral ecosystem services and disservices in the academic literature. • Search, Appraisal, Synthesis and Analysis (SALSA) method employed for the review. • Initial CICES classification and inventory of auroral ecosystem services (14) and ecosystem disservices (9). • Multiple opportunities for future research as well as auroral ES in management and decision making. • Novel introduction of "exosystem services" (EXS) to account for flows into socio-ecological systems from the space environment. Auroral ecosystem services (ES) is a subject that has not yet been formally addressed in the expansive ecosystem services literature. This study conducts a systematic literature review using the Search, Appraisal, Synthesis and Analysis (SALSA) method to investigate the vast multi-century auroral literature for synthesis with the ES concept and identifies the main ES provisioned by the auroral phenomenon. A total of 2,900 publications concerning the aurora were sourced from three scientific databases (ScienceDirect, Scopus and Google Scholar), 1,054 articles were advanced to the synthesis and analysis stage, and 525 of the most illustrative examples were retained for the purposes of this review. Based on the categorization in accordance with Version 5.1 of the Common International Classification for Ecosystem Services typology, a total of 14 auroral ES are identified: provisioning (4), regulation and maintenance (1) and cultural (9). In addition, 9 ecosystem disservices (EDS) are also identified and classified: provisioning (4), regulation and maintenance (3) and cultural (2). The aurora is found to function in geophysical, biophysical and socio-ecological systems in a variety of ways. A novel extension of the ES concept is introduced as "exosystem services" (EXS), accounting for the aurora as an overlap between flows into ecosystems from the space environment, mirroring the geosystem services (GS) concept and its flows into ecosystems from the subsurface environment. Auroral ES in management and decision-making is discussed, and multiple opportunities for additional research are explored. [ABSTRACT FROM AUTHOR]

SGLT2i reduce cardiac hypertrophy, but underlying mechanisms remain unknown. Here we explore a role for serine/threonine kinases (STK) and sodium hydrogen exchanger 1(NHE1) activities in SGLT2i effects on cardiac hypertrophy. Isolated hearts from db/db mice were perfused with 1 µM EMPA, and STK phosphorylation sites were examined using unbiased multiplex analysis to detect the most affected STKs by EMPA. Subsequently, hypertrophy was induced in H9c2 cells with 50 µM phenylephrine (PE), and the role of the most affected STK (p90 ribosomal S6 kinase (RSK)) and NHE1 activity in hypertrophy and the protection by EMPA was evaluated. In db/db mice hearts, EMPA most markedly reduced STK phosphorylation sites regulated by RSKL1, a member of the RSK family, and by Aurora A and B kinases. GO and KEGG analysis suggested that EMPA inhibits hypertrophy, cell cycle, cell senescence and FOXO pathways, illustrating inhibition of growth pathways. EMPA prevented PE-induced hypertrophy as evaluated by BNP and cell surface area in H9c2 cells. EMPA blocked PE-induced activation of NHE1. The specific NHE1 inhibitor Cariporide also prevented PE-induced hypertrophy without added effect of EMPA. EMPA blocked PE-induced RSK phosphorylation. The RSK inhibitor BIX02565 also suppressed PE-induced hypertrophy without added effect of EMPA. Cariporide mimicked EMPA's effects on PE-treated RSK phosphorylation. BIX02565 decreased PE-induced NHE1 activity, with no further decrease by EMPA. RSK inhibition by EMPA appears as a novel direct cardiac target of SGLT2i. Direct cardiac effects of EMPA exert their anti-hypertrophic effect through NHE-inhibition and subsequent RSK pathway inhibition. [Display omitted] • EMPA directly reduces RSK, Aurora A and B kinases in isolated murine diabetic heart. • EMPA inhibits phenylephrine-induced cardiac hypertrophy in H9c2 cells. • EMPA inhibits cell hypertrophy through inhibition of NHE1 and RSK activity. • Direct cardiac effects of EMPA exert anti-hypertrophy through NHE-RSK inhibition. [ABSTRACT FROM AUTHOR]

• Assessment of overburden interval is necessary in CCS. • Polygonal fault system might influence the secondary sealing integrity. • Gas chimney's are good analog for possible injected fluid migration path evaluation. • Qualitative interdisciplinary study is a quick tool to assess possible fate of injected fluids. This study evaluates potential secondary seals within the overburden in two CO 2 storage sites, Aurora and Smeaheia within the Horda Platform area, of the northern North Sea. Secondary sealing intervals provide for safe and reliable CO 2 storage as they prevent injected fluids from migrating into the atmosphere in the case of primary seal failure. This study analyzes the possible fate of the CO 2 plume in the case of primary seal failure for the Aurora and Smeaheia CO 2 storage sites by evaluating the secondary caprock and sealing potential of polygonal fault systems within the overburden intervals using structural reliability methods. Our findings suggest that a ductile secondary caprock is present in the overburden intervals of the storage sites, which could act as a secondary seal in the case of primary seal failure. The trapped hydrocarbon leaked from the Troll field within this ductile unit indicating a good secondary sealing potential. The study also reveals the presence of polygonal fault systems in the entire study area, but their frequency and orientation vary between layers. However, polygonal fault systems are not structurally stable, posing a risk of fault-parallel flow within the overburden interval. Nonetheless, the ductile clay-rich secondary caprock provides a seal for the polygonal fault systems within the interval. Due to either erosion or non-deposition, the ductile rock interval is not present in the east of the study area. As such, the critical risk for the Alpha structure in the Smeaheia injection site is the Vette fault and the efficiency of the primary Draupne caprock. Moreover, the crucial factor in the western Aurora site is the connectivity between the depleted Troll reservoirs and the CO 2 -injected pressurized reservoirs underneath. Based on our qualitative assessment, it is concluded that the overburden interval in the Horda Platform has adequate secondary sealing potential to hold and accumulate CO 2 in the case of primary seal failure. Still, further numerical simulations are recommended to quantify our findings for both the Aurora and Smeaheia sites. [ABSTRACT FROM AUTHOR]

Abstract The 4-aminoquinazoline core is an interesting pharmacophore and its applications in medicinal chemistry are wide spread. The core has been used for making many kinase inhibitors in past few years. Many researcher demonstrated 4-aminoquinazoline derivatives as specific kinase inhibitors, including tyrosine kinase and serine/theronine kinases. A number of anticancer drugs with 4-aminoquinazoline core are in the market, e.g. gefitinib, erlotinib, afatinib, lapatinib, decomitinib etc. 4-aminoquinazoline derivatives are applied for target specific treatment of lung, breast, colon, prostate cancers. In this review, we discussed the current development of 4-aminoquinazoline derivatives as kinase inhibitors and their uses as anticancer agents in recent years. Graphical abstract Image 1 Highlights • 4-Aminoquinazoline core is an important and versatile scaffold in drug design and discovery. • 4-aminoquinazoline s demonstrated as EGFR, HER2, VEGFR, RET, SRC, PI3K, aurora kinase inhibitors. • 4-Aminoquinazoline derivatives are used for cancers, e.g. lung cancer, breast cancer, and pancreatic cancer. • Newly identified 4-aminoquinazoline derivatives are discussed in the review. [ABSTRACT FROM AUTHOR]

This study summarizes the OASIS (Overburden Analysis and Seal Integrity Study for CO 2 Sequestration in the North Sea) project that focuses on assessing the containment risks associated with the geological carbon sequestration (CCS) of the Northern Lights project. CCS is viewed as one of the most effective solutions for reducing carbon emissions, as it captures carbon dioxide from point sources and permanently stores it in suitable geological formations. However, injecting CO 2 into the subsurface may have mechanical consequences, including fault reactivation, top seal fracturing, surface heave, etc. This study proposes an interdisciplinary workflow to characterize the caprock, faults, and overburden associated with CCS projects in the Horda Platform area, to improve injection-induced containment risk assessment. Our findings show that the proposed workflows and tools effectively characterize stress-related mechanical hazards. However, due to the complex nature of rocks, it is challenging to evaluate the top seal integrity using a single method. Therefore, the proposed interdisciplinary approach is more effective for any fluid injection site's characterization, given the complex nature of the subsurface and its behavior under injection-induced stress changes. This research paper adds knowledge about the top seal integrity assessment and the reliability of injected CO 2 , making CCS projects more reliable and safer. Although this study focuses on the northern North Sea, the proposed methods are equally applicable globally to characterize subsurface CO 2 storage sites. Apart from CCS projects, these research results can benefit other subsurface injection projects, such as water injection for reservoir management, wastewater injection for disposal, hydrogen storage, and hydraulic fracturing for unconventional hydrocarbon resources. • Brittleness indices property can reflect the rock integrity. • Seismic inverted properties resolve the data limitation issues within the overburden intervals. • An analytical structural reliability model can help evaluate the top sealing risks quickly. • Overburden interval rock properties must be realistic in any 3D field-scale geological models. • An interdisciplinary workflow is required for subsurface CCS site characterization. [ABSTRACT FROM AUTHOR]

Abstract This study reports on observations of large-scale atmospheric gravity waves/traveling ionospheric disturbances (AGWs/TIDs) using Global Positioning System (GPS) total electron content (TEC) and Fabry–Perot Interferometer's (FPI's) intensity of oxygen red line emission at 630 nm measurements over Svalbard on the night of 6 January 2014. TEC large-scale TIDs have primary periods ranging between 29 and 65 min and propagate at a mean horizontal velocity of ∼ 749–761 m/s with azimuth of ∼ 345–347 ° (which corresponds to poleward propagation direction). On the other hand, FPI large-scale AGWs have larger periods of ∼ 42–142 min. These large-scale AGWs/TIDs were linked to enhanced auroral activity identified from co-located all-sky camera and IMAGE magnetometers. Similar periods, speed and poleward propagation were found for the all-sky camera (∼ 60–97 min and ∼ 823 m/s) and the IMAGE magnetometers (∼ 32–53 min and ∼ 708 m/s) observations. Joule heating or/and particle precipitation as a result of auroral energy injection were identified as likely generation mechanisms for these disturbances. [ABSTRACT FROM AUTHOR]

Abstract Data of the MAIN cameras (Multiscale Aurora Imaging Network) obtained at Apatity (Kola Peninsula, Russia) during two winter seasons (2014/2015 and 2015/2016) have been used to study the substorms during different solar wind conditions. Solar wind parameters were taken from the 1-min sampled OMNI data base (http://cdaweb.gsfc.nasa.gov/cdaweb/istp_public/). Auroral disturbances were verified by the data of IMAGE magnetometers and by data of the all-sky camera at Apatity. All substorms were divided into different groups depending on the geomagnetic activity. First, the substorms were separated into two groups: substorms observed during storms and substorms under non-storm conditions. The substorms during storms were divided in sub-groups according to observations during different phases of the storm: initial, main and recovery phases, and the recovery phase was divided in near and late recovery phase. We considered also substorms during “structured recovery phase”, when the SYM/H index behavior was highly irregular. The substorms during non-storm conditions were classified as substorms under quiet conditions, when no structures in the solar wind were observed, and as substorms occurred when structures in the solar wind near the Earth were detected, but these structures did not provoke geomagnetic storms. It was shown that the latitude of the substorm onset was controlled by the value of the SYM/H index. Substorms at higher values of SYM/H index occurred to the North from the station zenith, and at smaller SYM/H values – to the South from it. The boundary between both types of substorms in terms of SYM/H index is in the range from ∼ −30 to ∼ −55 nT. It was found out also that the maximal relative intensity of auroras was greater for substorms with onset to the South from Apatity and smaller - for substorms with onset in zenith or to the North from Apatity. Highlights • Substorms during storm and non-storm conditions are studied. • Auroras observations by MAIN cameras in Apatity (Russia) are used. • Substorms division into groups according to the observation conditions is performed. • Onset auroras location dependences on different geomagnetic conditions are obtained. • Relation of SYM/H index and auroras locations over Apatity is observed. [ABSTRACT FROM AUTHOR]

Abstract Previous studies have shown that dynamic pressure impacts (e.g., shocks initiating CME storms) with southward IMF promptly lead to strong auroral nightside activity and concurrent poleward expansion (indicating strong nightside reconnection), and strong enhancements in convection and currents. Here we use a combination of ground-based ASI and radar observations to further describe this response, to address what is driving the strong activity, and to suggest similar driving in other situations. Consistent with some previous studies, we find that shock driven auroral activity and poleward expansion resembles a substorm, but starts from an already broad MLT sector without much subsequent azimuthal expansion and without classical brightening of the equatorward-most arc. We furthermore find a large enhancement of meso-scale ionospheric polar cap flows heading towards the nightside separatrix immediately after shock impact. Recent studies have shown that such enhanced flows often cross the separatrix leading to plasma sheet flow bursts, poleward boundary intensifications (PBIs), streamers, and poleward motion of the polar cap boundary from reconnection. Thus these flow enhancements, which must extend outward along field lines from the ionosphere, are an attractive candidate as the driver for the almost immediate strong auroral, current, and reconnection activity resulting from shock impact. We also discuss and present some evidence that this phenomenon may be more general, leading to similar oval responses without a shock impact, including during and following the expansion phase of some substorms. These suggestions could lead to some possibly fundamental questions, such as when do polar cap convection enhancements lead to a substorm growth phase versus leading directly to strong polar expansion of, and strong activity along, the auroral oval field line region? Highlights • Immediate strong auroral, current, reconnection activity results from shock impact. • Shock driven aurora resembles substorm expansion; broader, from poleward boundary. • Enhanced meso-scale polar cap flows towards nightside separatrix after shock impact. • Above enhanced flows attractive candidate for driver of immediate strong responses. [ABSTRACT FROM AUTHOR]

We report experimentally observed triggering criteria for Buneman instability and boundary conditions for existence of multiple double layers (MADL) in glow discharge plasma. The MADLs are generated by accelerating plasma electrons towards a positively biased electrode submerged in it. The boundary conditions for the formation and existence of MADL are obtained from the experiment in terms of electron drift velocity ( ν d ) and electron thermal velocity ( ν t e ). The MADL is found to exist within the range 3 ν t e ≥ ν d ≥ 1.3 ν t e . For the condition ν d ≥ 1.3 ν t e , rise of an instability and simultaneous formation of MADL is observed in the experiment. The analysis of fluctuations in floating potential showed that the instability has all the characteristics of Buneman instability. [ABSTRACT FROM AUTHOR]

Aurora kinases control multiple events during cell cycle progression and are essential for mitotic and meiotic bipolar spindle assembly and function. There are three Aurora kinases in mammals, some of which have oncogenic properties and all of which are overexpressed in multiple cancers. Pharmaceutical companies quickly made these kinases priority targets for the development of inhibitors to be used as cancer treatments. In this review, we focus on Aurora A, against which several inhibiting compounds have been discovered and made available; however, even though some of these compounds underwent clinical trials, none have yet gone beyond Phase III trials. The varying efficiencies and particularities of these drugs raise several questions that are explored in this review: is Aurora A even a good target? What biomarkers can we use to measure its activity in vivo ? How can we improve the Aurora A-inhibiting drugs? [ABSTRACT FROM AUTHOR]

While most patients with RET-altered cancer responded to the RET protein tyrosine kinase inhibitors (TKIs) pralsetinib (BLU667) and selpercatinib (LOXO292), few achieved a complete response. Heterogeneity in residual tumors makes it difficult to target their diverse genetic alterations individually. The aim of this study is to characterize the cancer cells that persist under continuous RET TKI treatment and identify the shared vulnerability of these cells. We analyzed residual RET-altered cancer cells under prolonged RET TKI treatment by whole exome sequencing (WES), RNA-seq analysis, and drug-sensitivity screening. These were followed by tumor xenograft experiments of mono- and combinational drug treatments. BLU667- and LOXO292-tolerated persisters were cellularly heterogeneous, contained slowly proliferating cells, regained low levels of active ERK1/2, and displayed plasticity in growth rate, which we designated as in the transition state of resistance (TSR). TSR cells were genetically heterogeneous. Aurora A/B kinases were among the most significantly upregulated genes and that the MAPK pathway activity had significantly higher transcript footprints. MEK1/2 and Aurora kinase inhibitors were the most effective drugs when combined with a RET kinase inhibitor. In a TSR tumor model, combination of BLU667 with an Aurora kinase or a MEK1/2 kinase inhibitor caused TSR tumor regression. Our experiments reveal that the heterogeneous TSR cancer cells under continuous RET TKI treatment converge on the targetable ERK1/2-driven Aurora A/B kinases. The discovery of the targetable convergent point in the genetically heterogeneous TSR points to an effective combination therapy approach to eliminate the residual tumors. [ABSTRACT FROM AUTHOR]

The high-latitude magnetic substorms observed at geomagnetic latitudes higher 70° MLAT under the substorm absence at the lower latitudes are known as "substorms on the contracted oval" or "polar" substorms. Such substorms appear during quiet or weakly disturbed space weather conditions. The study of 254 "polar" substorms, recorded at the Scandinavian IMAGE magnetometer chain during the winter seasons of 2010–2020, confirmed a tendency to occur in the late evening (∼19–23 MLT), that is a bit earlier than the "normal" substorms (22–24 MLT). It was found that before the onset of "polar" substorms, like "normal" substorms, there is an increase in the PC-index indicating an energy input into the magnetosphere. We established that "polar" substorms, like "normal" substorms, are accompanied by positive mid-latitude magnetic bays, demonstrating a substorm current wedge (SCW) development. Several "polar" substorms are examined in detail. The ionospheric electrojets and field-aligned currents (FAC) distribution was studied basing on the AMPERE satellites measurements. We found that "polar" substorm onsets are associated with an enhancement of FACs in a localized evening area. Thus, "polar" substorms exhibited the properties, typical for "normal" substorms, so, they could be referred as a specific type of substorms developing under rather quiet space weather conditions. • High-latitudes magnetic substorms known as "polar" substorms were studied. • IMAGE magnetometers, Barentsburg all-sky camera and AMPERE satellites data were used. • "Polar" substorms are accompanied by the positive mid-latitude bays indicating the SCW develop. • "Polar" substorm appearance is associated with an increasing of field-aligned currents in the evening sector. • PC-index enhancement, associated with an energy input into the magnetosphere, was found prior the substorm onsets. [ABSTRACT FROM AUTHOR]

Incursions of high-energy particles from space, specifically solar energetic particles and galactic cosmic rays, have significant effects on the Earth, including disruption of the Earth’s magnetic field, generation of electric fields strong enough to damage electronic devices as well as the production of auroras at low-latitudes, within 45° of the magnetic equator. We examine the relationships among 14 C production, auroral abundance, auroral color and sunspot abundance using existing data supplemented by a new dataset. The new dataset, based on Chinese and Korean records from A.D. 1100–1700, includes 46 new or revised records of sunspots and 279 records of low-latitude auroras. Low-latitude auroras are predominantly red (66%, 835 events) with lesser proportions of white (20%, 253 events) and black auroras (6%, 67 events). All other auroral colors (green, yellow, multicolored, blue and purple) aggregate to a total of 100 events (8%). Overall, white auroras are more frequent during times of higher 14 C production. We use two empirical methods of evaluating the flux of high-energy particles: modeled peaks and lows in 14 C production and peaks and lows in the 14 C calibration curve. We find that comparison to modeled 14 C production gives significant results. White auroras are significantly more abundant (98% probability) at times of high production of 14 C. Red auroras are somewhat more abundant (88% probability) at times of low production of 14 C. The abundances of black, multicolored, green, yellow, and blue auroras between times of low and high 14 C production are not significantly different. Violet/purple auroras are significantly more abundant (98% probability) at times of low 14 C production. The positive correlation of violet/purple auroras with times of low 14 C production rate and the lack of correlation of blue auroras with times of high 14 C production is surprising, for this portion of the visible spectrum contains strong emission lines and some lines with high energies of excitation. Observations of emissions in the blue to violet part of the spectrum may be biased towards time periods when the atmosphere is exceptionally clear, as these colors are more difficult for the human eye to perceive. [ABSTRACT FROM AUTHOR]

A comprehensive study of the ionospheric processes encountered during the superstorm which started on March 17th 2015 has been carried out using magnetometer, ionosonde, riometer, ionospheric tomography and an all-sky camera installed in the observatory of Sodankylä, Finland. The storm manifested a number of interesting features. From 12:00 on March 17 there was a significant decrease of critical frequencies foF2 and intensive sporadic Es layers were observed. During the disturbance, there was a lack of variation of the X-component of the magnetic field at times, but the absorption level measured by the riometer was high. A comparison of the electron density distributions for the quiet and disturbed days as shown in the tomography data were very different. Where results were available at the same times, the tomographic foF2 values coincided with the “real” foF2 values from the ionosonde. Where the ionosonde data was missing due to absorption, the tomographic foF2 values were used instead. The keograms from the all-sky camera showed that during disturbed days the aurorae manifested themselves as bright discrete forms. It was shown that the peaks of absorption due to particle precipitation seen by the riometer coincided in time with the brightenings of aurorae seen on the keograms. [ABSTRACT FROM AUTHOR]

This paper is aimed at physical causes of the small-scale transverse structure in the flows of auroral electrons, generating the corresponding small-scale structure of discrete auroras. The parallel electric field existing in the lower part of the auroral magnetosphere, in the auroral cavity region, in the presence of a strong upward field-aligned current, accelerates magnetospheric electrons to energies of ∼ 1 − 10 keV. The flow of these particles while maintaining the high density of the field-aligned current, produces a current-driven instability, which generates Alfvénic turbulence at short perpendicular wavelengths ≤ 1 km. These short-wavelength inertial Alfvén disturbances possess a nonzero parallell electric field, which modulates the electron flow velocity. The modulation occurring at high altitudes ≥ 10 4 km leads to a nonlinear effect of formation of strong density peaks at low altitudes of electron precipitation. The transverse, horizontal scales of the corresponding electron flow structure coincide with the small scales of the Alfvénic turbulence; and this structuring leads to non-uniformities in the auroral luminosity on the same scales, i.e., to small-scale structure of discrete auroras. [ABSTRACT FROM AUTHOR]

Bipolar Disorder is a severe disease characterized by pathological mood swings from major depressive episodes to manic ones and vice versa. The biological underpinnings of Bipolar Disorder have yet to be defined. As a consequence, pharmacological treatments are suboptimal. In the present paper we test the hypothesis that the molecular pathways involved with the direct targets of lithium, hold significantly more genetic variations associated with BD. A molecular pathway approach finds its rationale in the polygenic nature of the disease. The pathways were tested in a sample of ∼ 7,000 patients and controls. Data are available from the public NIMH database. The definition of the pathways was conducted according to the National Cancer Institute (http://pid.nci.nih.gov/). As a result, 3 out of the 18 tested pathways related to lithium action resisted the permutation analysis and were found to be associated with BD. These pathways were related to Reelin, Integrins and Aurora. A pool of genes selected from the ones linked with the above pathways was further investigated in order to identify the fine molecular mechanics shared by our significant pathways and also their link with lithium mechanism of action. The data obtained point out to a possible involvement of microtubule-related mechanics. [ABSTRACT FROM AUTHOR]

In just over two decades, structure based protein kinase inhibitor discovery has grown from trial and error approaches, using individual target structures, to structure and data driven approaches that may aim to optimize inhibition properties across several targets. This is increasingly enabled by the growing availability of potent compounds and kinome-wide binding data. Assessing the prospects for adapting known compounds to new therapeutic uses is thus a key priority for current drug discovery efforts. Tools that can successfully link the diverse information regarding target sequence, structure, and ligand binding properties now accompany a transformation of protein kinase inhibitor research, away from single, block-buster drug models, and toward “personalized medicine” with niche applications and highly specialized research groups. Major hurdles for the transformation to data driven drug discovery include mismatches in data types, and disparities of methods and molecules used; at the core remains the problem that ligand binding energies cannot be predicted precisely from individual structures. However, there is a growing body of experimental data for increasingly successful focussing of efforts: focussed chemical libraries, drug repurposing, polypharmacological design, to name a few. Protein kinase target similarity is easily quantified by sequence, and its relevance to ligand design includes broad classification by key binding sites, evaluation of resistance mutations, and the use of surrogate proteins. Although structural evaluation offers more information, the flexibility of protein kinases, and differences between the crystal and physiological environments may make the use of crystal structures misleading when structures are considered individually. Cheminformatics may enable the “calibration” of sequence and crystal structure information, with statistical methods able to identify key correlates to activity but also here, “the devil is in the details.” Examples from specific repurposing and polypharmacology applications illustrate these points. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases. [ABSTRACT FROM AUTHOR]

The upper atmosphere of Mars is a laboratory for better understanding the planetary atmosphere evolution, and is an example of the interaction of the solar wind with an unmagnetized planet that has only patches of crustal magnetic field. In that context, several space missions were launched to study the Martian environment and its aurorae, notably ESA's Mars Express discovered the first aurora-like structures, and more recently NASA's MAVEN, which is dedicated to understand the atmospheric escape. However, none of the existing missions have spectrometers in the visible spectral range for the observation of the upper atmosphere and the aurorae, but there are UV spectrometer which can be used to infer visible aurora emission. The UV aurorae on Mars have a counterpart in the visible spectral range which should be detectable under the right conditions. We discuss what are the most favorable conditions to observe these aurorae discernible with the naked eye. In this paper, we simulate the Martian aurora in the visible spectral range both with an experimental setup (the Planeterrella, which we use to measure intensity with respect to the naked eye) and with a numerical ionosphere simulation model (Trans⁎/Aeroplanets). We show that the electron impact on CO 2 produces strong emissions at 412 nm and 434 nm, i.e., in the blue part of the visible spectrum which are due to the CO 2 + (A) Fox–Duffendack–Barker bands. The modeling of the electron transport at Mars shows that these blue emissions as well as the emissions of the 630 nm (red) and 557.7 nm (green) lines of atomic oxygen may be observable several times during a solar cycle during strong solar events. The absence of visible spectrometers dedicated to these observations onboard existing space missions and the location of the different Martian rovers, far from the vertically aligned crustal magnetic field lines of Mars, have prevented so far the observations of such an aurora. In the foreseeable future, two missions may help observing these aurorae: the exo-Mars/Trace Gas Orbiter mission will carry a visible spectrometer which could be used to detect these events in the visible spectral range. NOMAD (Nadir and Occultation for Mars Discovery) will carry a UV-visible spectrometer in the 200–650 nm range. [ABSTRACT FROM AUTHOR]

The large-capacity on-chip cache often causes timing problems or erroneous transmission in the high-speed acquisition of massive data. However, many factors always affect the communication performance of the system. In this paper, a high-speed data acquisition system (DAS) based on DMA double cache mechanism is introduced. Aurora protocol is used for optical fiber transmission, and the line rate dynamic adaptive design of the X1 channel is realized. In the SDRAM controller, the DMA dual channel is targeted optimized, including memory ping-pong operation and channel arbiter. In addition, collecting data from the lower computer or transmitting data to the upper computer are both based on software instructions in our design, which is more flexible and stable than receiving data without instructions. Finally, to optimize the transmission process of cached data, we cascaded FIFOs in different modules. The results show that the system can receive optical fiber data at the rate of 7.57Gbps, and the average DMA communication efficiency reaches 76.9%. [ABSTRACT FROM AUTHOR]

• The Drake caprock shale possesses a relatively low brittleness indices value representing a ductile caprock. • A formation specific geomechanical properties range is proposed, which broadens the brittleness indices range hence higher resolution. • An initial basin-specific brittleness template has been proposed to evaluate NCS top seal shales. • The integrated caprock characterization workflow indicated the usefulness and viability of assessing any site-specific top seal. Evaluating top seal integrity is crucial for successful subsurface CO 2 storage. Caprock shale geomechanical properties are complex and influenced by various parameters and processes. It is challenging to understand the role of various factors affecting the geomechanical properties; therefore, an integrated approach is required to evaluate top seal shales. In this study, we investigated the caprock properties of the Early Jurassic shaly Drake Formation overlying the reservoir sandstones of Early Jurassic Cook and Johansen formations. The study area is the potential CO 2 storage site Aurora (the Longship CCS project), located in the Horda Platform area, offshore Norway. Based on lithological variations, the Drake Formation is subdivided into upper and lower Drake units. Variations of the geomechanical properties are investigated using wireline logs from 50 exploration wells, two 3D seismic cubes, and several 2D seismic lines. Elastic property-based brittleness indices of the Drake Formation caprock shales are evaluated to identify possible top seal quality. Moreover, seismic attributes and gas leakage scenarios are investigated qualitatively to assess the possibility of injected CO 2 escaping from the reservoir. Low brittleness indices value of the Drake Formation shale near the Aurora injection site indicated that the seal rock might diffuse the injection-related stress change and act as an effective top seal. Based on the integrated qualitative assessment, it is likely that the Drake caprock shale will be acted as an effective top seal in and around the Aurora storage site. However, due to the complex nature of caprock shales, we recommend field-scale numerical simulation to evaluate the injection-induced stress-strain effect. [ABSTRACT FROM AUTHOR]

Images of auroral emissions at far ultraviolet (FUV, 122–200 nm) wavelengths are useful tools with which to study magnetospheric–ionospheric coupling, as the scattered sunlight background in this region is low, allowing both dayside and nightside auroras to be imaged simultaneously. The ratio of intensities between certain FUV emission lines or regions can be used to characterise the precipitating particles responsible for auroral emissions, and hence is a useful diagnostic of magnetospheric dynamics. Here, we describe how the addition of simple transmission filters to a compact broadband imager design allows far ultraviolet emission ratios to be deduced while also providing large-scale instantaneous images of the aurora. The low mass and volume of such an instrument would make it well-suited for both small satellite Earth-orbiting missions and larger outer planet missions from which it could be used to characterise the tenuous atmospheres observed at several moons, as well as studying the auroral emissions of the gas giants. We present a study to investigate the accuracy of a technique to allow emission line ratio retrieval, as applied to the OI 130.4 nm and 135.6 nm emissions at Ganymede. The ratio of these emissions provides information about the atmospheric composition, specifically the relative abundances of O and O 2 . Using modelled FUV spectra representative of Ganymede׳s atmosphere, based on observations by the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS), we find that the accuracy of the retrieved ratios is a function of the magnitude of the ratio, with the best measurements corresponding to a ratio of ~ 1.3 . [ABSTRACT FROM AUTHOR]

Abstract: Modelling of N21P (5,3) contamination at the O+ doublet emissions in the region of 732nm is presented. The method is derived from a known relationship between emission from the N21P (5,3) band and emissions from the N21P (5,2), (4,1) and (3,0) bands. A synthetic molecular spectrum is used to quantify a temperature-dependent emission ratio of these band systems as a function of filter characteristics and emission altitude. Five optical observations of high-energy auroral periods on 9 January 2008 are compared with results from the synthetic spectrum. Two cameras from a high sensitivity, high frame rate (20Hz) ground based imager in combination with a co-located high resolution spectrograph are used to identify events which are dominated by molecular nitrogen emissions. There is good agreement between the observed and modelled ratios. The temperatures associated with these ratios agree well with temperature profiles extracted from fitting the synthetic spectra to the spectrograph data. A synthetic spectrum is important for future work when the removal of N21P (5,3) contamination from O+ (2P) doublet emissions is required at high temporal resolution. [Copyright &y& Elsevier]

We present ground-based auroral observations from Resolute Bay, Nunavut, Canada (74.73°N, 94.9°W) during January 2011. Two electron-multiplying CCD (EMCCD) imagers were operated at 31 frames per second. One was equipped with an all-sky field of view (FOV) lens and the other with a narrow (19°) FOV lens, centered on the geographic zenith (0° Az., 90° El.), a few degrees away from magnetic zenith (315° Az., 88° El.). The Resolute Incoherent Scatter Radar (RISR) was operating in a mode that enabled common-volume observations with the imagers. Being well inside the polar cap, the magnetic field at Resolute Bay is considered ‘open’ and connects to the lobes of the magnetotail. However, there is no clear consensus on whether polar cap aurorae occur on open or closed field lines. The electron acceleration is likely driven by direct solar wind processes, distant tail lobe processes or plasma sheet processes. One possible mechanism for accelerating the precipitating electrons is the parallel electric field of inertial Alfvén waves. The dynamic nature of the small-scale auroral features, observed on several nights, and the altitude extent of the ionization observed with RISR provide support for this hypothesis. [ABSTRACT FROM AUTHOR]

Abstract: The Io footprint (IFP) is a set of auroral spots and an extended tail resulting from the strong interaction between Io and the Jovian magnetosphere. For the first time, we present measurements of the brightness and precipitated power for each individual spot, using the image database gathered from 1997 to 2009 with the Hubble Space Telescope in the Far-UV domain. We show that the relative brightness of the spots varies with the System III longitude of Io. Moreover, our novel measurement method based on 3D simulations of the auroral features allows to derive the precipitated energy fluxes from images on which the emission region is observed at a slant angle. Peak values as high as 2W/m2 are observed for the main spot, probably triggering a localized and sudden heating of the atmosphere. Additionally, strong brightness differences are observed from one hemisphere to another. This result indicates that the location of Io in the plasma torus is not the only parameter to control the brightness, but that the magnetic field asymmetries also play a key role. Finally, we present new data confirming that significant variations of the spots' brightness on timescales of 2–4min are ubiquitous, which suggests a relationship with intermittent double layers close to Jovian surface. [Copyright &y& Elsevier]

Abstract: Following magnetic reconnection in a planetary magnetotail, newly closed field lines can be rapidly accelerated back towards the planet, becoming “dipolarized” in the process. At Saturn, dipolarizations are initially identified in magnetometer data by looking for a southward turning of the magnetic field, indicating the transition from a radially stretched configuration to a more dipolar field topology. The highly stretched geometry of the kronian magnetotail lobes gives rise to a tail current which flows eastward (dusk to dawn) in the near equatorial plane across the centre of the tail. During reconnection and associated dipolarization of the field, the inner edge of this tail current can be diverted through the ionosphere, in a situation analogous to the substorm current wedge picture at Earth. We present a picture of the current circuit arising from this tail reconfiguration, and outline the equations which describe the field–current relationship. We show a new in situ example of a dipolarization identified in the Cassini magnetometer data and use this formalism to estimate the ionospheric current density that would arise based on in situ tail measurements of the magnetic field and the implications for corresponding auroral electron acceleration in regions of upward directed field-aligned current. We then present a separate example of data from the Cassini UVIS instrument where we observe small ‘spots’ of auroral emission lying near the main oval; features suggested to be associated with dipolarizations in the tail. In the example shown, such auroral features are the precursor to more intense activity associated with recurrent energisation via particle injections from the tail following reconnection. [Copyright &y& Elsevier]

Abstract: Global Navigation Satellite System (GNSS) based radio occultation (RO) technique has shown powerful ability in ionospheric electron density profiling in the past decade. The most frequently used Abel inversion method in electron density retrieval has some biases because of the used spherical symmetry assumption. Our previous series simulations and evaluations mainly concentrated in the middle and low latitude regions have shown some systematical bias especially in lower altitude of low latitude region. However, the RO derived electron density quality in the high latitude and polar region is rarely investigated and not quantitatively clear yet. In this study, the Abel inversion error over high latitude and polar regions are systematically investigated for the first time based on NCAR-TIEGCM simulations and real data evaluations. The TIMED data driven NCAR-TIEGCM modeled electron density during 2008 are used to simulate the COSMIC RO events. The Abel inversion error can then be estimated by comparing Abel retrievals from TIEGCM simulated occultation with the original TIEGCM simulations. The Abel inversion can reproduce the season, altitude, latitude, and local time variation patterns of electron density and auroral zone electron density nighttime enhancement well in high latitude and polar region. The Abel inversion tends to underestimate the electron density in the auroral zone and overestimate it on both the equatorward and poleward sides of the auroral zone. As simulated by the TIEGCM model, the significant relative error (>25%) mainly occurs in lower altitude (<250km) inside and around auroral zone region. Above 250km, the relative error mostly is less than 25%. Specifically, RMSE (root mean square error) of NmF2 error from simulation is ∼8.5%. The Abel error under real ionosphere situation would be worse because the ionosphere could be more complicated and noisier than the model simulation. The error distribution and its seasonal, local time and latitude variations can be explained by the spherical symmetry assumption used in the Abel inversion associated with the corresponding ionospheric electron density variations. The comparisons between PFISR and COSMIC RO electron density during 2007–2011 and some previous validation studies agree well with our simulation results. We hope these results can stimulate more studies in high latitude ionospheric research using RO data. [Copyright &y& Elsevier]

Abstract: Global air quality datasets with a coarse resolution have to be downscaled to become useful for regional interpretation, for instance by applying dynamical downscaling. Here, the downscaling ability of the regional air quality model AURORA (Air quality modelling in Urban Regions using an Optimal Resolution Approach) for surface ozone concentrations is evaluated over a model domain covering a large part of Belgium. The impact of two different one-way nesting resolution jumps is studied. Additionally, the effect of horizontal grid spacing on the simulation results is investigated. Model evaluation against measurements from a number of urban/suburban and rural background stations and a gridded interpolation map shows that the model is capable of reproducing the observed temporal and spatial patterns. The results indicate that the two applied nesting resolution jumps are comparably successful in simulating the surface ozone concentrations, despite the large resolution jump (25–3 km) in one of the approaches. The impact of horizontal resolution on the modelled time series at different types of locations is relatively small, with the average difference around 1% of the mean concentrations. However, the benefits of the higher resolution express themselves in the spatial correlations and temporal variances of the simulation results. [Copyright &y& Elsevier]

Abstract: This paper presents a new calculation of neutral gas heating by precipitating auroral electrons. It is found that the heating rate of the neutral gas is significantly lower than previous determinations below 200km altitude. The neutral gas heating arises from the many exothermic chemical reactions that take place from the ions and excited species created by the energetic electrons. The calculations show that less than half the energy initially deposited ends up heating the neutral gases. The rest is radiated or lost in the dissociation of O2 because the O atoms do not recombine in the thermosphere. This paper also presents a new way of calculating the heating rate per ionization that can be used for efficient determination of the overall neutral gas heating for global thermosphere models. The heating rates are relatively insensitive to the neutral atmosphere when plotted against pressure rather than altitude coordinates. At high altitudes, the heating rates are sensitive to the thermal electron density and long-lived species. The calculations were performed with the Field Line Interhemispheric Plasma (FLIP) model using a 2-stream auroral electron precipitation model. The heating rate calculations in this paper differ from previous heating rate calculations in the treatment of backscattered electrons to produce better agreement with observed flux spectra. This paper shows that more realistic model auroral electron spectra can be obtained by reflecting the up going flux back to the ionosphere at the upper boundary of the model. In this case, the neutral gas heating rates are 20%–25% higher than when the backscattered flux escapes from the ionosphere. [Copyright &y& Elsevier]

Abstract: Auroral nighttime infrared emission observed by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the Thermosphere–Ionosphere–Mesosphere Energetics and Dynamics (TIMED) satellite is used to develop an empirical model of geomagnetic storm enhancements to E-region electron densities. The empirical model is called STORM-E and will be incorporated into the 2012 release of the International Reference Ionosphere (IRI). The proxy for characterizing the E-region response to geomagnetic forcing is NO+(v) Volume Emission Rates (VER) derived from the TIMED/SABER 4.3μm channel limb radiance measurements. The storm-time response of the NO+(v) 4.3μm VER is most sensitive to auroral particle precipitation. A statistical database of storm-time to climatological quiet-time ratios of SABER-observed NO+(v) 4.3μm VER are fit to widely available geomagnetic indices using the theoretical framework of linear impulse-response theory. The STORM-E model provides a dynamic storm-time correction factor to adjust a known nighttime quiescent E-region electron density peak concentration for geomagnetic enhancements due to auroral particle precipitation. Part I of this series gives a detailed description of the algorithms and methodologies used to derive NO+(v) VER from SABER 4.3μm limb emission measurements. In this paper, Part II of the series, the development of the E-region electron density storm-time correction factor is described. The STORM-E storm-time correction factor is fit to a single geomagnetic index. There are four versions of the STORM-E model, which are currently independent of magnetic local time. Each version is fit to one of the following indices: HP, AE, Ap, or Dst. High-latitude Incoherent Scatter Radar (ISR) E-region electron density measurements are compared to STORM-E predictions for various geomagnetic storm periods during solar cycle 23. These comparisons show that STORM-E significantly improves the prediction of E-region electron density enhancements due to auroral particle precipitation, in comparison to the nominal IRI model or to the quiet-time baseline electron density concentrations measured by ISR. The STORM-E/ISR comparisons indicate that the STORM-E fits to the Ap-, AE-, and HP-indices are comparable in both absolute accuracy and relative dynamical response. Contrarily, the Dst-index does not appear to be a suitable input driver to parameterize the E-region electron density response to geomagnetic activity. [Copyright &y& Elsevier]

Abstract: The different types of asymmetry observed in the energy distributions of electrons and heavy-ions (M/Q=16-44) during signatures of electron precipitation in the Martian ionosphere have been classified. This has been achieved using the space plasma instrumentation of MEX ASPERA-3 from peri-centre altitude to 2200km. ASPERA-3 ELS observes signatures of electron precipitation on 43.0% of MEX orbits. Unaccelerated electrons in the form of sudden electron flux enhancements are the most common type of electron precipitation signature at Mars and account for of the events observed in this study. Electrons that form unaccelerated electron precipitation signatures are either local ionospheric electrons with enhanced density, or electrons transported from another region of ionosphere, solar wind or tail, or a combination of local and transported electrons. The heating of electrons has a strong influence on the shape of most electron energy spectra from accelerated precipitation signatures. On most occasions the general flow of heavy-ions away from Mars is unchanged during the precipitation of electrons, which is thought to be the result of the finite gyroradius effect of the heavy-ions on crustal magnetic field lines. Only of events show some form of heavy-ion acceleration that is either concurrent or at the periphery of an electron precipitation signature. The most common combination of electron and heavy-ion energy distributions for signatures of electron precipitation involves electrons that visually have very little asymmetry or are isotropic and heavy-ions that have a upward net flux, and suggest the upward current associated with aurora. Due to a lack of reliable measurements of electrons travelling towards Mars, it is likely we miss further evidence of upward currents. The second most common combination of electron and heavy-ion energy distributions for signatures of electron precipitation, are those distributions of electrons that are asymmetric and have an net upward flux, with distributions of heavy-ions that also have a net upward flux. Energy distributions of heavy-ions with a net flux towards Mars occur half as often as heavy-ions with an upward net flux. There is also evidence to suggest we observe downward currents during electron precipitation signatures when we find energy distributions of electrons that are asymmetric and have an upward net flux, combined with energy distributions of heavy-ions that have a downward net flux. Wave particle interactions and downward parallel electric fields may be responsible for electrons that display a large amount of asymmetry in the upward direction of the energy distribution and have a upward net flux. [Copyright &y& Elsevier]

Abstract: We analyze the planetary and exoplanetary science that can be carried out with precursor as well as future low frequency radio instruments on the Moon, assessing the limiting noise sources, comparing them to the average and peak spectra of all planetary radio components as they will be seen from the Lunar surface or orbit. We identify which objectives will be accessible with each class of instrument, and discuss the interest of these observations compared to observations by planetary probes and to ground-based observations by large low-frequency radio arrays. The interest of goniopolarimetry is emphasized for pathfinder missions. [Copyright &y& Elsevier]

Abstract: In the present work, a bias-aware optimal interpolation in conjunction with the Hollingsworth–Lönnberg method to estimate error covariance matrices was applied as data assimilation algorithm in the regional scale air quality model AURORA to assimilate ground level O3 and NO2 concentrations. The study was conducted over the domain Belgium including part of its neighbouring areas with grid resolution of 3 × 3 km2. Data assimilation was carried out for the retrospective simulation in post-processing (offline) mode for a summer and a winter month. Observations were provided by the AIRBASE data archive. Since the air quality model AURORA is presumed to represent background conditions, only the background stations within the domain have been taken into account. The validation of the proposed method was carried out by leaving observations of ten monitoring stations out in one run of the data assimilation process and another ten stations out in the next run and so on (a “leave ten out approach”). The proposed method has been evaluated in both spatial as well temporal domain against various statistical indicators such as correlation coefficient (CORR), root mean square error (RMSE), index of agreement (IOA) and mean fractional bias (MFB). For both the O3 and NO2, the extensive validation results have clearly shown substantial improvement in the data assimilation results over AURORA free run in both the seasons. The results over 70 validation stations show that CORR increased from 0.4 to 0.8 for O3, 0.3 to 0.6 for NO2 while average RMSE reduced from 27.9 to 12.6 for O3 and from 17.4 to 11.0 for NO2 for the month of June. Similar improvements have been observed for the month of Dec as well. Spatial CORR, IOA for monthly means of both the O3 and NO2 concentrations were also increased considerably. The results clearly indicate that the applied bias aware optimal interpolation in conjunction with Hollingsworth–Lönnberg method is a very promising candidate for the statistical correction of regional scale air quality modelling results for the retrospective simulation. [Copyright &y& Elsevier]

Abstract: Polar Earth orbit (PEO) is a peculiar orbit where energetic auroral electrons and low-temperature ionospheric plasma coexist. There is a risk of charging and subsequent arcing in PEO. The plasma environment, namely its density and energy, is the crucial parameter for spacecraft charging analysis. We statistically analyzed the environmental condition in PEO using the data of auroral electrons and thermal ions measured by DMSP (Defense Meteorological Satellite Program) satellites. The probability of a given combination of current densities of auroral electrons and thermal ions has been derived. The energy spectrum of the auroral electrons is also classified into several types, and its correlation with the thermal ions is analyzed. Combinations of the plasma parameters used by a spacecraft charging simulation software have been identified and a database containing the probability of occurrence of each combination has been formulated. [Copyright &y& Elsevier]

Abstract: This paper describes a technique for intercalibrating particle and optical measurements from the Reimei microsatellite using an ionospheric model. Reimei has three auroral cameras (“MAC”), together with electron and ion energy spectrum analysers (“ESA/ISA”). The maximum electron energy measured is 12keV, which means that during high-energy events, the particle data are often missing an important part of the energy flux. Although the total electron energy flux can be estimated from the optical measurements, the MAC data must be accurately calibrated, which is complicated by an unknown and variable background from sources such as the moon and snow reflection. Using unsaturated ESA measurements of the complete electron spectrum as input for an ionospheric model, the coincident camera observations can be calibrated, allowing estimates to be made of the total electron energy flux at other times during the same event, when the maximum energy is well above that measured by ESA. [Copyright &y& Elsevier]

Abstract: Using magnetometer data acquired by geosynchronous satellite and all-sky images from a ground optical station in the conjugate area, we show propagation of aurora surge repeating in a thin and narrow aurora arc at the poleward boundary of the aurora zone. The surge repetition correlated with the Pi2s at the geosynchronous altitudes. One-to-one conjunctions of the surge and Pi2 pulse were not always observed. The westward or eastward propagation directions of the surge corresponded to the clockwise or counterclockwise wave polarizations in the equatorial plane. Propagation velocities of the poleward surge were in the range of 0.2–0.5°/s or 12–30km/s at 100km altitudes. We discuss the propagating surge at poleward boundary in conjunction with bi-directional flows in the first 10min intervals of Pi2 onset that were inferred by from the Pi2 epoch analyses of magnetometer data at geosynchronous altitudes. [Copyright &y& Elsevier]

Abstract: The coupling of Jupiter''s magnetosphere and ionosphere plays a vital role in creating its auroral emissions. The strength of these emissions is dependent on the difference in speed of the rotational flows within Jupiter''s high-latitude thermosphere and the planet''s magnetodisc. Using an azimuthally symmetric global circulation model, we have simulated how upstream solar wind conditions affect the energy and direction of atmospheric flows. In order to simulate the effect of a varying dynamic pressure in the upstream solar wind, we calculated three magnetic field profiles representing compressed, averaged and expanded ‘middle’ magnetospheres. These profiles were then used to solve for the angular velocity of plasma in the magnetosphere. This angular velocity determines the strength of currents flowing between the ionosphere and magnetosphere. We examine the influence of variability in this current system upon the global winds and energy inputs within the Jovian thermosphere. We find that the power dissipated by Joule heating and ion drag increases by and from our compressed to expanded model respectively. We investigated the effect of exterior boundary conditions on our models and found that by reducing the radial current at the outer edge of the magnetodisc, we also limit the thermosphere''s ability to transmit angular momentum to this region. [Copyright &y& Elsevier]

Abstract: Information and communication technologies (ICTs) devices operate within the atmosphere around the earth as part of their global network. They are therefore subjected to all the natural activities that take place in this global space. Solar storm activities continue to increase in intensity and NASA has issued a warning that a powerful solar storm may hit the earth sometime in 2012. This has the potential to lead to ICTs devices not functioning at all if this happens. In this paper a worst case scenario of this storm, if it was to happen, is discussed with its pros and cons. [Copyright &y& Elsevier]

Abstract: Cepstral normalisation in automatic speech recognition is investigated in the context of robustness to additive noise. In this paper, it is argued that such normalisation leads naturally to a speech feature based on signal to noise ratio rather than absolute energy (or power). Explicit calculation of this SNR-cepstrum by means of a noise estimate is shown to have theoretical and practical advantages over the usual (energy based) cepstrum. The relationship between the SNR-cepstrum and the articulation index, known in psycho-acoustics, is discussed. Experiments are presented suggesting that the combination of the SNR-cepstrum with the well known perceptual linear prediction method can be beneficial in noisy environments. [Copyright &y& Elsevier]

Abstract: We present observations of the ionospheric response to a hot flow anomaly (HFA) interacting with the magnetosphere. On 4 July 2007, the THEMIS spacecraft observed an HFA, a disruption of the solar wind flow, on both sides of the bow shock. The ionospheric response was measured by global auroral images taken over the southern hemisphere by Polar UVI, by ground based magnetometers and photometers in Antarctica, and by the THEMIS Ground Based Observatory (GBO) magnetometers (GMAGs) in the northern hemisphere. Polar UVI observations show a region of enhanced auroral emission in the morning sector about 10min after the THEMIS spacecraft observed the HFA. This region of enhanced emission was located above South Pole station which observed magnetic perturbations and an increase in the auroral luminosity. The THEMIS GMAGs in the conjugate hemisphere also observed magnetic perturbations consistent with a traveling convection vortex (TCV). Polar UVI tracked the spatial and temporal development of the region of enhanced emission. Slow anti-sunward motion was observed as the emission weakened and then re-brightened over the course of about 10min. Simultaneously, the THEMIS GMAG array observed anti-sunward motion of the magnetic impulse with a velocity much greater than that of the auroral emission. These are the first simultaneous observations of localized enhanced auroral emission and the associated magnetic impulse propagating anti-sunward over a distance of several 1000km. We suggest that the origin of the magnetic perturbation and resulting auroral emission is the deformation of the magnetopause due to the HFA–magnetosphere interaction. The different propagation speeds of the auroral emission in the southern hemisphere and the magnetic perturbation in the northern hemisphere imply either (1) a decoupling of the auroral emission and field-aligned current signature or (2) a decoupling of these processes between the two hemispheres. The large difference in the ionospheric conductivity between the northern (summer) and southern (winter) hemispheres may be an important factor in this decoupling. More observations are needed to adequately address the decoupling mechanism. [Copyright &y& Elsevier]

Abstract: The Galileo spacecraft explored Jupiter’s magnetotail in a low-inclination orbit, where it detected the signatures of tail reconnection. In this paper, we examine and classify the tail reconnection signatures into four types: dipolarizations, strong northward B θ excursions, tailward-moving plasmoids and planetward-moving plasmoids. The distribution of these four types of events is used to infer the most probable location of the Jovian tail reconnection site to be near 0200 LT at a planetocentric distance of 80 Jovian radii. Dipolarizations are mainly observed planetward of this point, and strong northward B θ excursions and plasmoids are found mostly tailward. The observations also suggest that the Jovian tail reconnection starts at a point (neutral point), a localized region in the tail, instead of along an extended azimuthal line (X-line). Using the updated Khurana’s Jupiter’s magnetospheric model, which includes the external field and the effects of the swept-back configuration of tail field lines, we map the signatures of Jovian tail reconnection into the Jupiter’s ionosphere. We confirm that the dawn auroral storms or the polar dawn spots observed by the Hubble Space Telescope (HST) are located close to the extrapolated footpoints of tail dipolarizations and could be the auroral signatures of tail reconnection. [ABSTRACT FROM AUTHOR]

Abstract: The downward field-aligned current region plays an active role in magnetosphere–ionosphere coupling processes associated with aurora. A quasi-static electric field structure with a downward parallel electric field forms at altitudes between 800km and 5000km, accelerating ionospheric electrons upward, away from the auroral ionosphere. Other phenomena including energetic ion conics, electron solitary waves, low-frequency wave activity, and plasma density cavities occur in this region, which also acts as a source region for VLF saucers. Results are presented from high-altitude Cluster observations with particular emphasis on the characteristics and dynamics of quasi-static electric field structures. These, extending up to altitudes of at least 4–5 Earth radii, appear commonly as monopolar or bipolar electric fields. The former occur at sharp boundaries, such as the polar cap boundary whereas the bipolar fields occur at softer boundaries within the plasma sheet. The temporal evolution of quasi-static electric field structures, as captured by the pearls-on-a-string configuration of the Cluster spacecraft, indicates that the formation of electric field structures and of ionospheric plasma density cavities are closely coupled processes. A related feature of the downward current is a broadening of the current sheet with time, possibly related to the depletion process. Preliminary studies of the coupling of electric fields in the downward current region, show that small-scale structures are typically decoupled from the ionosphere, similar to what has been found for the upward current region. However, exceptions are also found where small-scale electric fields couple perfectly between the ionosphere and Cluster altitudes. Recent FAST results indicate that the degree of coupling differs between sheet-like and curved structures, and that it is typically partial. The electric field coupling further depends on the current–voltage relationship, which is highly non-linear in the downward current region, and still unrevealed, as to its specific form. [Copyright &y& Elsevier]

Abstract: We present a record of auroral observations in Barcelona in the late 18th century and the early 19th century by Francisco Salvá. We have consulted the original manuscripts containing the meteorological readings made by Salvá. Dates of 19 aurorae and one brief auroral description have been identified. The annual number of aurorae observed by Salvá is compared with other auroral series at higher latitudes. Moreover, we have calculated the variation of geomagnetic latitude of Barcelona during the period under study. The main characteristic of this data set is an abrupt decrease of the annual number of auroral observations recorded in Barcelona around 1793. [Copyright &y& Elsevier]

Abstract: We developed a new numerical model of the Jovian magnetosphere–ionosphere coupling current system in order to investigate the effects of diurnal variation of ionospheric conductance. The conductance is determined by ion chemical processes that include the generation of hydrogen and hydrocarbon ions by solar EUV radiation and auroral electrons precipitation. The model solves the torque equations for magnetospheric plasma accelerated by the radial currents flowing along the magnetospheric equator. The conductance and magnetospheric plasma then change the field-aligned currents (FACs) and the intensity of the electric field projected onto the ionosphere. Because of the positive feedback of the ionospheric conductance on the FAC, the FAC is the maximum on the dayside and minimum just before sunrise. The power transferred from the planetary rotation is mainly consumed in the upper atmosphere on the dayside, while it is used for magnetospheric plasma acceleration in other local time (LT) sectors. Further, our simulations show that the magnetospheric plasma density and mass flux affect the temporal variation in the peak FAC density. The enhancement of the solar EUV flux by a factor of 2.4 increases the FAC density by 30%. The maximum density of the FAC is determined not only by the relationship between the precipitating electron flux and ionospheric conductance, but also by the system inertia, i.e., the inertia of the magnetospheric plasma. A theoretical analysis and numerical simulations reveal that the FAC density is in proportion to the planetary angular velocity on the dayside and to the square of the planetary angular velocity on the nightside. When the radial current at the outer boundary is fixed at values above 30MA, as assumed in previous model studies, the peak FAC density determined at latitude 73°–74° is larger than the diurnal variable component. This result suggests large effects of this assumed radial current at the outer boundary on the system. [Copyright &y& Elsevier]

Abstract: Current dayside optical studies of Aurora Australis from the Amundsen-Scott Research Station at the South Pole (74 degrees magnetic latitude) show some striking differences from optical results reported from Svalbard. A 6-channel meridian scanning photometer operating during the past three austral winters shows, in particular, the 630nm emission is much lower, on average, than the Arctic dayside aurora and very weak on some days. The 558nm intensity is higher relative to 630nm suggesting the incoming electrons have a higher average energy. There are notable differences in auroral forms, giving further evidence of asymmetries in the two dayside ovals. [Copyright &y& Elsevier]

Abstract: We demonstrate that under some magnetospheric conditions protons and oxygen ions are accelerated once per Saturn magnetosphere rotation, at a preferred local time between midnight and dawn. Although enhancements in energetic neutral atom (ENA) emission may in general occur at any local time and at any time in a Saturn rotation, those enhancements that exhibit a recurrence at a period very close to Saturn''s rotation period usually recur in the same magnetospheric location. We suggest that these events result from current sheet acceleration in the 15–20Rs range, probably associated with reconnection and plasmoid formation in Saturn''s magnetotail. Simultaneous auroral observations by the Hubble Space Telescope (HST) and the Cassini Ultraviolet Imaging Spectrometer (UVIS) suggest a close correlation between these dynamical magnetospheric events and dawn-side transient auroral brightenings. Likewise, many of the recurrent ENA enhancements coincide closely with bursts of Saturn kilometric radiation, again pointing to possible linkage with high latitude auroral processes. We argue that the rotating azimuthal asymmetry of the ring current pressure revealed in the ENA images creates an associated rotating field aligned current system linking to the ionosphere and driving the correlated auroral processes. [Copyright &y& Elsevier]