Formation of plasma around a small meteoroid: 1. Kinetic theory

This article is a companion to Dimant and Oppenheim [2017] https://doi.org/10.1002/2017JA023963.This paper calculates the spatial distribution of the plasma responsible for radar head echoes by applying the kinetic theory developed in the companion paper. This results in a set of analytic expressions for the plasma density as a function of distance from the meteoroid. It shows that at distances less than a collisional mean free path from the meteoroid surface, the plasma density drops in proportion to 1/R where R is the distance from the meteoroid center; and, at distances much longer than the mean‐free‐path behind the meteoroid, the density diminishes at a rate proportional to 1/R2. The results of this paper should be used for modeling and analysis of radar head echoes.This work was supported by NSF grant AGS-1244842. (AGS-1244842 - NSF

Multiple Quantum NMR Dynamics in Dipolar Ordered Spin Systems

We investigate analytically and numerically the Multiple Quantum (MQ) NMR dynamics in systems of nuclear spins 1/2 coupled by the dipole-dipole interactions in the case of the dipolar ordered initial state. We suggest two different methods of MQ NMR. One of them is based on the measurement of the dipolar temperature in the quasi-equilibrium state which establishes after the time of order T2 after the MQ NMR experiment. The other method uses an additional resonance 45^0 -pulse after the preparation period of the standard MQ NMR experiment in solids. Many-spin clusters and correlations are created faster in such experiments than in the usual MQ NMR experiments and can be used for the investigation of many-spin dynamics of nuclear spins in solids.Comment: 11 pages, 3 figures. accepted for publication in Physical Review

Aerosol Pollution from Small Combustors in a Village

Urban air pollution is widely recognized. Recently, there have been a few projects that examined air quality in rural areas (e.g., AUPHEP project in Austria, WOODUSE project in Denmark). Here we present the results within the International Cooperation Project RER/2/005 targeted at studying the effect of local combustion processes to air quality in the village of Brzezina in the countryside north-west of Wroclaw (south western Poland). We identified the potential emission sources and quantified their contributions. The ambient aerosol monitoring (PM10 and elemental concentrations) was performed during 4 measurement cycles, in summer 2009, 2010 and in winter 2010, 2011. Some receptor modeling techniques, factor analysis-multiple linear regression analysis (FA-MLRA) and potential source localization function (PSLF), have been used. Different types of fuel burning along with domestic refuse resulted in an increased concentration of PM10 particle mass, but also by an increased in various other compounds (As, Pb, Zn). Local combustion sources contributed up to 80% to PM10 mass in winter. The effect of other sources was small, from 6 to 20%, dependently on the season. Both PM10 and elemental concentrations in the rural settlement were comparable to concentrations at urban sites in summer and were much higher in winter, which can pose asignificant health risk to its inhabitants

ОСОБЛИВОСТІ СІЛЬСЬКОГОСПОДАРСЬКОГО ВИКОРИСТАННЯ ДЕРНОВО-КАРБОНАТНИХ ҐРУНТІВ (РЕНДЗИН) ВОЛИНСЬКОГО ПОЛІССЯ

The features of sod-carbonate soils (rendzin) and their contiguity to Upper Cretaceous deposits within the boundaries of the Volyn Polissia are considered. The research was conducted in two areas and similar results were obtained. The term "rendziny" is briefly explained and their genesis, soil profile morphology, humus reserves, processes of humus formation and dehumification are defined. The most lasting effect of humus accumulation is noted when organic fertilizers are applied. This indicates that the use of organic and organo-mineral fertilizer systems leads to the stabilization of humus accumulation in the arable layer of the humus horizon.To maintain a high level of humus formation, it is necessary to apply organic fertilizers, and for a high degree of enrichment of humus with nitrogen, it is necessary to supplement them with mineral fertilizers. Of all the applied fertilization systems, the most optimal is the organo-mineral (combined) system (N60P60K120+8.9 t/ha of manure), which contributes to the formation of a powerful humus horizon characterized by the highest thermodynamic stability of the humus complex.The transformation of colloidal forms of humus was noted. When plowing rendzin on control (without fertilizers), the content of GH in the plowed layer decreases by 2 times, which indicates increased mineralization due to plowing. The use of fertilizer systems makes it possible to restrain PG mineralization by 16–40%, and the organo-mineral system exerts a great influence on its stabilization.     Розглянуто особливості дерново-карбонатних ґрунтів (рендзин), їхню приуроченість до верхньокрейдових відкладень у межах Волинського Полісся. Дослідження проведено на двох площах та отримано аналогічні результати. Коротко пояснено термін «рендзини» і визначено їх генезу, морфологію грунтового профілю, запаси гумусу, процеси утворення гумусу та дегуміфікації. Найбільш тривалим ефект накопичення гумусу відзначається при внесенні органічних добрив. Це свідчить про те, що застосування органічної та органо-мінеральної системи добрива призводить до стабілізації накопичення гумусу в орному шарі гумусового горизонту.Для підтримки високого рівня утворення гумусу необхідно обов'язково вносити органічні добрива, а для високого ступеня збагачення гумусу азотом необхідно доповнювати їх мінеральними добривами. З усіх застосовуваних систем удобрення найбільш оптимальною є органо-мінеральна (комбінована) система (N60P60K120+8,9 т/га гною), яка сприяє утворенню потужного гумусового горизонту, що характеризується найвищою термодинамічною стійкістю гумусового комплексу.Відзначено трансформацію колоїдних форм гумусу. При розорюванні рендзин на контролі (без добрив) вміст ПГ у орному шарі зменшується у 2 рази, що свідчить про підвищену мінералізацію внаслідок розорювання. Застосування систем добрива дозволяє стримувати мінералізацію ПГ на 16–40%, причому великий вплив на його стабілізацію чинить органо-мінеральна система

End states, ladder compounds, and domain wall fermions

A magnetic field applied to a cross linked ladder compound can generate isolated electronic states bound to the ends of the chain. After exploring the interference phenomena responsible, I discuss a connection to the domain wall approach to chiral fermions in lattice gauge theory. The robust nature of the states under small variations of the bond strengths is tied to chiral symmetry and the multiplicative renormalization of fermion masses.Comment: 10 pages, 4 figures; final version for Phys. Rev. Let

Steering effect on the shape of islands for homoepitaxial growth of Cu on Cu(100)

The steering effect on the growth of islands is investigated by combining molecular dynamics (MD) and kinetic Monte Carlo (KMC) simulations. Dynamics of depositing atoms and kinetics of atoms on a substrate are realized by MD and KMC, respectively. The reported experimental results on the asymmetric island growth [van Dijken {\it et al.}, Phys. Rev. Lett. {\bf 82}, 4038 (1999).] is well reproduced. A salient phenomenon, the reversal of the asymmetry, is found as the island size increases, and attributed to the asymmetric flux on the lower terrace of island.Comment: 5 figur

The Effects of Negative Legacies on the Adjustment of Parentally Bereaved Children and Adolescents

This is a report of a qualitative analysis of a sample of bereaved families in which one parent died and in which children scored in the clinical range on the Child Behavior Check List. The purpose of this analysis was to learn more about the lives of these children. They were considered to be at risk of developing emotional and behavioral problems associated with the death. We discovered that many of these “high risk” children had a continuing bond with the deceased that was primarily negative and troubling for them in contrast to a comparison group of children not at risk from the same study. Five types of legacies, not mutually exclusive, were identified: health related, role related, personal qualities, legacy of blame, and an emotional legacy. Coping behavior on the part of the surviving parent seemed to make a difference in whether or not a legacy was experienced as negative