scholarly journals Seasonal dependence of the Earth's radiation belt – new insights

2021 ◽  
Vol 39 (1) ◽  
pp. 181-187
Author(s):  
Rajkumar Hajra
Keyword(s):  
Radiation Belt ◽  
Space Environment ◽  
Flux Variation ◽  
Annual Peak ◽  
Radiation Belt Electrons ◽  
Potential Impact ◽  
Two Peaks ◽  
First Time ◽  
Earth’S Radiation Belt

Abstract. Long-term variations in the relativistic (∼MeV) electrons in the Earth's radiation belt are explored to study seasonal features of the electrons. An L-shell dependence of the seasonal variations in the electrons is reported for the first time. A clear ∼6 month periodicity, representing one/two peaks per year, is identified for 1.5–6.0 MeV electron fluxes in the L shells between ∼3.0 and ∼5.0. The relativistic electron flux variation is strongest during solar cycle descending to minimum phases, with weaker/no variations during solar maximum. If two peaks per year occur, they are largely asymmetric in amplitude. The peaks essentially do not have an equinoctial dependence. Sometimes the peaks are shifted to solstices, and sometimes only one annual peak is observed. No such seasonal features are prominent for L<3.0 and L>5.0. The results imply varying solar/interplanetary drivers of the radiation belt electrons at different L shells. This has a potential impact on the modeling of the space environment. Plausible solar drivers are discussed.

scholarly journals Seasonal dependence of the Earth's radiation belt: new insight

2020 ◽  
Author(s):  
Rajkumar Hajra
Keyword(s):  
Radiation Belt ◽  
Solar Maximum ◽  
Space Environment ◽  
Annual Peak ◽  
Radiation Belt Electrons ◽  
Potential Impact ◽  
Two Peaks ◽  
First Time ◽  
Earth’S Radiation Belt

Abstract. Long-term variations of the relativistic (~ MeV) electrons in the Earth's radiation belt are explored to study seasonal features of the electrons. An L-shell dependence of the seasonal variations of the electrons is revealed for the first time. A clear ~ 6-month periodicity is identified for 1.5–6.0 MeV electron fluxes in the L-shells between ~ 3.0 and ~ 5.0, representing two peaks per year. The two-peak variation is strong during solar cycle descending to minimum phases, with weaker/no variations during solar maximum. The peaks are largely asymmetric in amplitude. These are not essentially equinoctial: sometimes the peaks are shifted to solstices and sometimes one annual peak is only observed. No such seasonal features are prominent for L  5.0. The results imply varying solar/interplanetary drivers of the radiation belt electrons at different L-shells. This has a potential impact on the modeling of space environment. Plausible solar drivers are discussed.

Radiation belt electron acceleration during periods of low plasma density

2021 ◽  
Author(s):  
Hayley Allison ◽  
Yuri Shprits ◽  
Irina Zhelavskaya ◽  
Dedong Wang ◽  
Artem Smirnov
Keyword(s):  
Plasma Density ◽  
Cold Plasma ◽  
Radiation Belt ◽  
Electron Acceleration ◽  
Number Density ◽  
Chorus Waves ◽  
Radiation Belt Electrons ◽  
Plasma Depletion

&lt;p&gt;Electrons in the Van Allen radiation belts can have energies in excess of 7 MeV. We present a unique way of analyzing phase space density data which demonstrates that local acceleration is capable of heating electrons up to 7 MeV. The Van Allen Probes mission not only provided unique measurements of ultra-relativistic radiation belt electrons, but also simultaneous observations of plasma waves that allowed for the routine inference of total plasma number density. Based on long-term observations, we show that the underlying plasma density has a controlling effect over local acceleration to ultra-relativistic energies, which occurs only when the plasma number density drops down to very low values (~10 cm&lt;sup&gt;-3&lt;/sup&gt;). The VERB-2D model is used to simulate ultra-relativistic electron acceleration during an event which exhibits an extreme cold plasma depletion. The results show that a reduced electron plasma density allows chorus waves to efficiently resonate with electrons up to ultra-relativistic energies, producing enhancements from 100s of keV up to &gt;7 MeV via local diffusive acceleration. We analyse statistically the observed chorus wave power during ultra-relativistic enhancement events, considering the contribution from both upper and lower band chorus waves. The PINE density model allows for the investigation of global magnetospheric density changes. We analyze the how the global cold plasma density changes during ultra-relativistic enhancement events and compare to in-situ point measurements of the plasma density.&lt;/p&gt;

Transition to parenthood programmes

2019 ◽  
Author(s):  
Jane Barlow
Keyword(s):  
Transition To Parenthood ◽  
Well Being ◽  
Perinatal Period ◽  
Developmental Period ◽  
Evidence Based ◽  
Life Chances ◽  
Potential Impact ◽  
Related Stress ◽  
First Time

For first-time parents, the ‘transition to parenthood’ is a significant period, not only in terms of changes for the parents and the related stress that such changes may involve, but also in terms of the needs of the unborn/newborn baby. This reflects the fact that the perinatal period is now recognized to be a ‘sensitive’ developmental period in terms of the baby’s neurodevelopment and thereby a significant window of opportunity to equalize the life chances of all children. This chapter examines some of the key changes that can occur during the ‘transition to parenthood’ and the potential impact in terms of long-term well-being of the infant and child. Innovative and evidence-based methods of working to support the couple in the transition to parenthood are described, and the effectiveness of such programmes reviewed in terms of both parental and infant well-being.

scholarly journals Long‐term monitoring of energetic protons at the bottom of Earth's radiation belt

Space Weather ◽  
2020 ◽  
Author(s):  
K. Yoshioka ◽  
Y. Miyoshi ◽  
S. Kurita ◽  
M. Teramoto ◽  
F. Tsuchiya ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Earth’S Radiation Belt

scholarly journals A Comparison of Radial Diffusion Coefficients in 1-D and 3-D Long-Term Radiation Belt Simulations

2020 ◽  
Author(s):  
Alexander Drozdov ◽  
Hayley Allison ◽  
Yuri Shprits ◽  
Nikita Aseev
Keyword(s):  
Radiation Belt ◽  
Low Frequency ◽  
Radial Diffusion ◽  
Ulf Waves ◽  
Electron Radiation ◽  
Particle Interactions ◽  
Physical Mechanisms ◽  
Modeling And Forecasting ◽  
Radiation Belt Electrons

&lt;p&gt;Radial diffusion is one of the dominant physical mechanisms that drives acceleration andloss of the radiation belt electrons due to wave-particle interactions with ultra-low frequency (ULF) waves, which makes it very important for radiation belt modeling and forecasting.&amp;#160; We investigate the sensitivity of several parameterizations of the radial diffusion including Brautigam and Albert (2000), Ozeke et al. (2014), Ali et al. (2016), and Liu et al. (2016) on long-term radiation belt modeling using the Versatile Electron Radiation Belt (VERB) code.&amp;#160; Following previous studies, we first perform 1-D radial diffusion simulations.&amp;#160; To take into account effects of local acceleration and loss, we perform additional 3-D simulations, including pitch-angle, energy and mixed diffusion.&lt;/p&gt;

Somatic Embryogenesis and In vitro Plant Regeneration in Vigna trilobata (L.) Verd. - A Potential Pasture Legume

1970 ◽  
Vol 19 (1) ◽  
pp. 89-99
Author(s):  
K. Choudhary ◽  
M. Singh ◽  
M. S. Rathore ◽  
N. S. Shekhawat
Keyword(s):  
Somatic Embryogenesis ◽  
Growth Regulators ◽  
Somatic Embryos ◽  
Basal Medium ◽  
Long Term Study ◽  
Continuous Application ◽  
First Time ◽  
Pasture Legume

This long term study demonstrates for the first time that it is possible to propagate embryogenic Vigna trilobata and to subsequently initiate the differentiation of embryos into complete plantlets. Initiation of callus was possible on 2,4-D. Somatic embryos differentiated on modified MS basal nutrient medium with 1.0 mg/l  of 2,4-D and 0.5 mg/l  of Kn. Sustained cell division resulted in globular and heart shape stages of somatic embryos. Transfer of embryos on to a fresh modified MS basal medium with 0.5 mg/l of Kn and 0.5 mg/l of GA3 helped them to attain maturation and germination. However, the propagation of cells, as well as the differentiation of embryos, were inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking these growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in Vigna species are discussed. Key words: Pasture  legume, Vigna trilobata, Globular, Heart shape, somatic embryogenesis D.O.I. 10.3329/ptcb.v19i1.4990 Plant Tissue Cult. & Biotech. 19(1): 89-99, 2009 (June)

An Evaluation of Provincial Macroeconomic Performance in Vietnam

2017 ◽  
pp. 34-47
Author(s):  
Hoi Le Quoc ◽  
Nam Pham Xuan ◽  
Tuan Nguyen Anh
Keyword(s):  
Development Strategy ◽  
Institutional Transformation ◽  
Economic Indicators ◽  
Macroeconomic Performance ◽  
Economic Development Strategy ◽  
Socio Economic Development ◽  
The Cost ◽  
Development Objectives ◽  
First Time

The study was targeted at developing a methodology for constructing a macroeconomic performance index at a provincial level for the first time in Vietnam based on 4 groups of measurements: (i) Economic indicators; (ii) oriented economic indicators; (iii) socio-economic indicators; and (iv) economic - social – institutional indicators. Applying the methodology to the 2011 - 2015 empirical data of all provinces in Vietnam, the research shows that the socio-economic development strategy implemented by those provinces did not provide balanced outcomes between growth and social objectives, sustainability and inclusiveness. Many provinces focused on economic growth at the cost of structural change, equality and institutional transformation. In contrast, many provinces were successful in improving equality but not growth. Those facts threaten the long-term development objectives of the provinces.

NEW VARIETIES OF CURRANTS AND GOOSEBERRY BREEDING PLANTS

1970 ◽  
pp. 41-46
Author(s):  
O. D. Golyaeva ◽  
O. V. Kurashev ◽  
S. D. Knyazev ◽  
А. Yu. Bakhotskaya
Keyword(s):  
Powdery Mildew ◽  
Genetic Basis ◽  
Black Currant ◽  
Leaf Spots ◽  
Agricultural Sciences ◽  
Berry Crops ◽  
New Varieties ◽  
First Time ◽  
Red Currant

The main goal of the scientific institution was and remains to improve the assortment of fruit and berry crops for the development of domestic horticulture. Black currant breeding at VNIISPK was started by A.F Tamarova and continued by the doctor of agricultural Sciences T.P.Ogoltsova and doctor of agricultural Sciences S.D. Knyazev. A long-term breeding program has been developed. The main goals of the program are to create black currant cultivars with continuous resistance to diseases, first of all powdery mildew, as wells resistance to pests, i.e. bud mite. As a result of the long-term work, over 40 black currant cultivars have been developed, 14 of them are zoned. Red currant breeding was led by the candidate of agricultural Sciences L.V. Bayanova; since 2001 the work has been continued by the candidate of agricultural Sciences O.D. Golyaeva. ‘Heinemanns Rote Spӓtlese’, the descendant of R. multiflorum Kit., was involved in the red currant breeding for the first time in Russia. On its genetic basis, a series of late maturing cultivars with long and dense racemes was created. At the Institute, in total 21cultivars of red currants have been developed, 13 of them are zoned. At present, red currant cultivars make up 25.5% of the zoned assortment in Russia. The first research on gooseberries was stated by V.P. Semakin and A.F Tamarova; since 1992 the systematic gooseberry breeding has been carried out by the candidate of agricultural Sciences O.V. Kurashev. On the basis of Grossularia robusta, we have created gooseberry forms that are resistant to powdery mildew and leaf spots. These forms are highly productive, weakly thorned, having bush habit suitable for mechanized harvest. The result of breeding activities was the transfer of 6 gooseberry cultivars to State agricultural testing: ‘Solnechny Zaychik’, ‘Nekrasovsky’, ‘Yupiter’, ‘Zemlianichny’, ‘Moryachok’ and ‘Discovery’.

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