Minimization of Fungicidal Applications Against Potato Late Blight in the North Caucasian Region: Use of the “Agrodozor” System

Late blight is considered to be the most devastating potato disease, which control requires application of fungicides able to significantly contaminate the environment and accumulate in agricultural products. Pesticide load on potato fields can be reduced via optimization of the scheme of protective treatments. Such optimization can be performed using a mathematical simulator describing the dependence of late blight-caused yield losses on the weather data and an “Agrodozor” decision support system (DSS). The performed analysis of a situation in the regions of the North Caucasus allowed us to determine three zones differing in the disease harmfulness and characterized by potential yield losses at the level of <10, 10-20, and >20 % and the probability of disease appearance in field during 30, 77, and 90 % of seasons, respectively. Using the “Agrodozor” DSS, we calculated the optimum dates of fungicidal treatments for these zones and showed that, comparing to the commonly used routine scheme of treatments, the use of this DSS provides a significant reduction of the number of such treatments and, therefore, the corresponding costs for their arrangement, as well as reduction of the total toxicity index of the required protective measures

Asymmetry of Magnetosheath Flows and Magnetopause Shape During Low Alfvén Mach Number Solar Wind

Previous works have emphasized the significant influence of the solar wind Alfvén Mach number (MA) on magnetospheric dynamics. Here we report statistical, observational results that pertain to changes in the magnetosheath flow distribution and magnetopause shape as a function of solar wind MA and interplanetary magnetic field (IMF) clock angle orientation. We use all Cluster 1 data in the magnetosheath during the period 2001–2010, using an appropriate spatial superposition procedure, to produce magnetosheath flow distributions as a function of location in themagnetosheath relative to the IMF and other parameters. The results demonstrate that enhanced flows in the magnetosheath are expected at locations quasi-perpendicular to the IMF direction in the plane perpendicular to the Sun-Earth line; in other words, for the special case of a northward IMF, enhanced flows are observed on the dawn and dusk flanks of the magnetosphere, while much lower flows are observed above the poles. The largest flows are adjacent to themagnetopause. Using appropriate magnetopause crossing lists (for both high and lowMA), we also investigate the changes inmagnetopause shape as a function of solarwindMA and IMF orientation. Comparing observed magnetopause crossings with predicted positions from an axisymmetric semi-empirical model, we statistically show that the magnetopause is generally circular during high MA, while is it elongated (albeit with moderate statistical significance) along the direction of the IMF during low MA. These findings are consistent with enhanced magnetic forces that prevail in the magnetosheath during lowMA. The component of the magnetic forces parallel to the magnetopause produces the enhanced flows along and adjacent to the magnetopause, while the component normal to the magnetopause exerts an asymmetric pressure on the magnetopause that deforms it into an elongated shape

An improved empirical model of electron and ion fluxes at geosynchronous orbit based on upstream solar wind conditions

A new empirical model of the electron fluxes and ion fluxes at geosynchronous orbit (GEO) is introduced, based on observations by Los Alamos National Laboratory (LANL) satellites. The model provides flux predictions in the energy range ~1 eV to ~40 keV, as a function of local time, energy, and the strength of the solar wind electric field (the negative product of the solar wind speed and the z component of the magnetic field). Given appropriate upstream solar wind measurements, the model provides a forecast of the fluxes at GEO with a ~1 h lead time. Model predictions are tested against in‐sample observations from LANL satellites and also against out‐of‐sample observations from the Compact Environmental Anomaly Sensor II detector on the AMC‐12 satellite. The model does not reproduce all structure seen in the observations. However, for the intervals studied here (quiet and storm times) the normalized root‐mean‐square deviation < ~0.3. It is intended that the model will improve forecasting of the spacecraft environment at GEO and also provide improved boundary/input conditions for physical models of the magnetosphere.Key PointsNew model of electron and ion fluxes at GEO (driven by ‐vBz) provides a ~1 h forecast of fluxes in the energy range ~1 eV to ~40 keVThe main benefit from the new model is the ability to predict the fluxes at GEO in advanceForecasts are a good match to observations during quiet times and storm timesPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134149/1/swe20339_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134149/2/swe20339.pd

Multistep Dst development and ring current composition changes during the 4–6 June 1991 magnetic storm

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95117/1/jgra16069.pd

THE THREE-DIMENSIONAL EVOLUTION OF ION-SCALE CURRENT SHEETS: TEARING AND DRIFT-KINK INSTABILITIES IN THE PRESENCE OF PROTON TEMPERATURE ANISOTROPY

We present the first three-dimensional hybrid simulations of the evolution of ion-scale current sheets, with an investigation of the role of temperature anisotropy and associated kinetic instabilities on the growth of the tearing instability and particle heating. We confirm the ability of the ion cyclotron and firehose instabilities to enhance or suppress reconnection, respectively. The simulations demonstrate the emergence of persistent three-dimensional structures, including patchy reconnection sites and the fast growth of a narrow-band drift-kink instability, which suppresses reconnection for thin current sheets with weak guide fields. Potential observational signatures of the three-dimensional evolution of solar wind current sheets are also discussed. We conclude that kinetic instabilities, arising from non-Maxwellian ion populations, are significant to the evolution of three-dimensional current sheets, and two-dimensional studies of heating rates by reconnection may therefore over-estimate the ability of thin, ion-scale current sheets to heat the solar wind by reconnection

The Induction of APC with a Distinct Tolerogenic Phenotype via Contact-Dependent STAT3 Activation

BACKGROUND: Activation of the signal transducer and activator of transcription 3 (STAT3) within antigen presenting cells (APCs) is linked to abnormal APCs differentiation and function. We have previously shown that STAT3 is activated within APC by a novel contact-dependent mechanism, which plays a key role in mediating the immunomodulatory effects of hMSC. In order to better understand the underlying mechanisms that control APC maturation in a contact dependent manner, we extended our observation to tumor cells. Tumors were shown to secrete a variety of tumor-derived factors that activate STAT3 within infiltrating APCs. We now tested whether tumor cells can activate STAT3 within APC using the contact-dependent mechanism, in addition to soluble factors, and compared these two STAT3 activating pathways. PRINCIPAL FINDINGS: We demonstrate that in addition to tumor-derived secreted factors tumor cells activate STAT3 by a mechanism that is based on cell-cell interaction. We further demonstrate that these two STAT3 activating mechanisms differ in their JAK usage and their susceptibility to JSI-124 inhibition thereby representing two distinct pathways. Significantly, although both pathways activate STAT3, they modulate DCs maturation in a different manner that results in disparate phenotypic outcomes. Whereas the soluble-dependent pathway results in an immature phenotype, the contact-dependent pathway results in an apparently mature phenotype. Albeit their mature-like phenotype these latter cells express the tolerogenic markers ILT3 and ILT4 and possess T cell inhibitory activity. SIGNIFICANCE: This data suggests that, in at least certain cellular microenvironments, cell:cell interactions represent a novel way to activate STAT3 signaling, uncouple APC activation events and consequently regulate immunity and tolerance. Significantly, we have now demonstrated that this contact-dependent signaling pathway differs from that mediated by soluble factors and cytokines, inducing disparate phenotypic outcome, suggesting these two mechanisms have different and possibly complementary biological functions

Solar Wind Turbulence and the Role of Ion Instabilities

International audienc

Origins of the Ambient Solar Wind: Implications for Space Weather

The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure

The Earth: Plasma Sources, Losses, and Transport Processes

This paper reviews the state of knowledge concerning the source of magnetospheric plasma at Earth. Source of plasma, its acceleration and transport throughout the system, its consequences on system dynamics, and its loss are all discussed. Both observational and modeling advances since the last time this subject was covered in detail (Hultqvist et al., Magnetospheric Plasma Sources and Losses, 1999) are addressed