508 Works

Trapped and precipitating protons in the inner magnetosphere as seen by IMAGE

J Perez, X Zhang, P Brandt, D Mitchell, J Jahn, C Pollock & S Mende
[1] Images from the IMAGE satellite of precipitating protons (SU12/FUV) and trapped protons at 8.5 (MENA) and 33 keV (HENA) are compared during three periods: ( 1) 12 August 2000 from 1000 UT to 1145 UT just after the peak of a strong geomagnetic storm, ( 2) 2 June 2001 from 0100 to 0345 UT during the main phase and initial recovery of a weak storm, and ( 3) 18 June 2001 from 1400 to...

Effects of tropospheric ozone pollution on net primary productivity and carbon storage in terrestrial ecosystems of China

Wei Ren, Hanqin Tian, Mingliang Liu, Chi Zhang, Guangsheng Chen, Shufen Pan, Benjamin Felzer & Xiaofeng Xu
We investigated the potential effects of elevated ozone (O-3) along with climate variability, increasing CO2, and land use change on net primary productivity (NPP) and carbon storage in China's terrestrial ecosystems for the period 1961 - 2000 with a process-based Dynamic Land Ecosystem Model (DLEM) forced by the gridded data of historical tropospheric O-3 and other environmental factors. The simulated results showed that elevated O-3 could result in a mean 4.5% reduction in NPP and...

Performance of soybean cultivars in Alabama, 2014

Kathryn M. Glass, , & Jon H. Brasher
"December 2014."

Electron propagator calculations on C-60 and C-70 photoelectron spectra

V. G. Zakrzewski, O. Dolgounitcheva & J.V. Ortiz
Vertical ionization energies of C60 and C70 fullerenes are calculated with semidirect implementations of electron propagator methods and a triple- plus polarization basis set. These predictions are in close agreement with photoelectron spectra for final states in which the Koopmans description is qualitatively valid. Many correlation states, where the latter description fails, are predicted by methods with nondiagonal self-energies.

Second-order, two-electron Dyson propagator theory: Comparisons for vertical double ionization potentials

T. Ida & J.V. Ortiz
The second-order, two-electron Dyson propagator is derived using superoperator theory with a spin-adapted formulation. To include certain ladder diagrams to all orders, the shifted-denominator SD2 approximation is made. Formal and computational comparisons with other approximations illustrate the advantages of the SD2 procedure. Vertical double ionization potentials DIPs for a set of closed-shell molecules are evaluated with the second-order propagator and the SD2 method. The results of the SD2 approximation are in good agreement with experiment....

Partial photoionization cross sections of and Rydberg radicals

A.M. Velasco, C. Lavin, I. Martin, J. Melin & J.V. Ortiz
ammonium and oxonium Rydberg radicals from the outermost, occupied orbitals of their respective ground states are reported. These properties are known to be relevant in photoelectron dynamics studies. For the present calculations, the molecular-adapted quantum defect orbital method has been employed. A Cooper minimum has been found in the 3sa1-kpt2 Rydberg channel of NH4 beyond the ionization threshold, which provides the main contribution to the photoionization of this radical. However, no net minimum is found...

Experimental and numerical investigation of saltwater intrusion dynamics in flux-controlled groundwater systems

Sun Woo Chang & T. Prabhakar Clement
Sea level rise and reduction of groundwater fluxes due to changes in rainfall patterns are the two major climate change–induced hydrological variables that can severely affect saltwater intrusion in coastal aquifers. In this study we use a combination of laboratory experiments and numerical simulations to study the impacts of changes in one of these climate change–induced hydrological variables, groundwater flux, on saltwater intrusion process. We have completed experiments in a laboratory-scale model to study the...

Preliminary performance of soybeans in Alabama, 2020

Henry G. Jordan
Caption title. "January 13, 2021."

Surface Green’s function calculations: A nonrecursive scheme with an infinite number of principal layers

Aleksey Kletsov, Yuri Dahnovsky & J.V. Ortiz
A novel computational method for a surface Green’s function matrix is introduced for the calculation of electrical current in molecular wires. The proposed nonrecursive approach includes an infinite number of principal layers and yields the second-order matrix equation for the transformed Green’s function matrix. The solution is found by the direct diagonalization of the auxiliary matrix without any iteration process. As soon as complex roots of the auxiliary matrix Gˆ S are calculated, the gaps...

Examining Audience Reaction to B2B Content Marketing Delivered via Social Media

James Cole & Emory Serviss
Social media provide multiple platforms and tactics to reach business-to-business (B2B) audiences with content they may rely upon to make purchasing decisions. But while content marketing has drawn some academic interest over the past decade, particularly in the field of media effects where audience reactions are studied with traditional theoretical frameworks, there is very little scholarly research examining how content marketing in social media influences audiences, particularly with regard to purchase decisions. In the highly...

Fishes of the Streams of Acadia National Park, Maine

Justin C. Havird, Jennifer K. Parker & Bruce Connery
Acadia National Park (ANP) is a non-continuous conglomerate of park lands interspersed with private lands, which is located mainly on Mount Desert Island, ME. Surveys of fishes in ANP have largely ignored or under-sampled most of the streams on the island. Reported here are the results of a 2009 survey that sampled freshwater fishes in 43 streams flowing through Park boundaries. Overall, 19 species were collected, and many were recorded from specific streams for the...

Alabama cotton variety tests 1974

Cover title. "February 1975."

1977 Alabama grain sorghum performance tests

& Cliff G. Currier
Cover title. "February 1978."

Multiple Colonizations Lead to Cryptic Biodiversity in an Island Ecosystem: Comparative Phylogeography of Anchialine Shrimp Species in the Ryukyu Archipelago, Japan

David A Weese, Yoshihisa Fujita & Scott R. Santos
Archipelagos of the Indo-West Pacific are considered to be among the richest in the world in biodiversity, and phylogeographic studies generally support either the center of origin or the center of accumulation hypothesis to explain this pattern. To differentiate between these competing hypotheses for organisms from the Indo-West Pacific anchialine ecosystem, defined as coastal bodies of mixohaline water fluctuating with the tides but having no direct oceanic connections, we investigated the genetic variation, population structure,...

Integrating info-gap decision theory with robust population management: a case study using the Mountain Plover

Max Post Van Der Burg & Andrew J. Tyre
Wildlife managers often make decisions under considerable uncertainty. In the most extreme case, a complete lack of data leads to uncertainty that is unquantifiable. Information-gap decision theory deals with assessing management decisions under extreme uncertainty, but it is not widely used in wildlife management. So too, robust population management methods were developed to deal with uncertainties in multiple-model parameters. However, the two methods have not, as yet, been used in tandem to assess population management...

Toward more realistic projections of soil carbon dynamics by Earth system models

Yiqi Luo, Anders Ahlstrom, Steven D. Allison, Niles H. Batjes, Victor Brovkin, Nuno Carvalhais, Adrian Chappell, Philippe Ciais, Eric A. Davidson, Adrien C. Finzi, Katerina Georgiou, Bertrand Guenet, Oleksandra Hararuk, Jennifer W. Harden, Yujie He, Francesca Hopkins, Lifen Jiang, Charlie Koven, Robert B. Jackson, Chris D. Jones, Mark J. Lara, Junyi Liang, A. David McGuire, William Parton, Changhui Peng … & Tao Zhou
Soil carbon (C) is a critical component of Earth system models (ESMs), and its diverse representations are a major source of the large spread across models in the terrestrial C sink from the third to fifth assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Improving soil C projections is of a high priority for Earth system modeling in the future IPCC and other assessments. To achieve this goal, we suggest that (1) model...

Field evaluation of synthetic lure (3-methyl-1-butanol) when compared to non odor-baited control in capturing Anopheles mosquitoes in varying land-use sites in Madagascar

Sarah Zohdy, Kristin Derfus, Mbolatiana Tovo Andrianjafy, Patricia C. Wright & Thomas R. Gillespie
Background: Malaria is the 4th largest cause of mortality in Madagascar. To better understand malaria transmission dynamics, it is crucial to map the distribution of the malaria vectors, mosquitoes belonging to the genus Anopheles. To do so, it is important to have a strong Anopheles-specific lure to ensure the maximum number of captures. Previous studies have isolated volatiles from the human skin microbiota and found the compound 3-methyl-1-butanol to be the most attractive to the...

Discovery and Broad Relevance May Be Insignificant Components of Course-Based Undergraduate Research Experiences [CUREs] for Non-Biology Majors

Cissy J. Ballen, Seth K. Thompson, Jessamina E. Blum, Nicholas P. Newstrom & Cotner Cotner
Course-based undergraduate research experiences (CUREs) are a type of laboratory learning environment associated with a science course, in which undergraduates participate in novel research. According to Auchincloss et al. (CBE Life Sci Educ 2104; 13:29-40), CUREs are distinct from other laboratory learning environments because they possess five core design components, and while national calls to improve STEM education have led to an increase in CURE programs nationally, less work has specifically focused on which core...

Global hybrid simulation of mode conversion at the dayside magnetopause

Feng Shi, Yu Lin & Xueyi Wang
Mode conversion at the magnetopause has been suggested to lead to the generation of kinetic Alfven waves (KAWs) and effective mass transport from the solar wind into the magnetosphere. To investigate the mode conversion process in the dynamic dayside system, a 3D global hybrid simulation associated with a quasiparallel shock under a radial interplanetary magnetic field (IMF) is carried out, in which the foreshock compressional pulses are selfconsistently generated by the interaction between the solar...

Investigation of the Interaction Between Magnetosheath Reconnection and Magnetopause Reconnection Driven by Oblique Interplanetary Tangential Discontinuity Using Three-Dimensional Global Hybrid Simulation

Zhifang Guo, Lin Yu & Wang Xueyi
Magnetosheath reconnection due to the interaction of an interplanetary directional discontinuity with the bow shock and Earth's magnetosphere under an initially northward interplanetary magnetic field (IMF) has been investigated in previous simulations (e.g., Guo et al., 2018, https://doi.org/10.1029/2018ja025679). Under an initially southward IMF, the magnetosheath reconnection could interact with reconnection at the magnetopause. In this study, using three-dimensional (3D) globalscale hybrid simulations, we present cases with incoming tangential discontinuities (TDs) in an initially southward IMF,...

Global-scale simulation of foreshock structures at the quasi-parallel bow shock

Yu Lin
A two-dimensional, global-scale hybrid simulation is carried out to study the kinetic structure of the quasi-parallel bow shock. In the simulation the bow shock forms by the interaction of the supersonic solar wind and the geomagnetic field. Strong temporal electromagnetic waves occur in the shock transition and foreshock regions due to backstreaming and reflected ions at the bow shock. This self-consistent, global-scale simulation shows the formation of diamagnetic cavities in the foreshock regions of the...

Global Hybrid Simulations of Interaction Between Interplanetary Rotational Discontinuity and Bow Shock/Magnetosphere: Can Ion-Scale Magnetic Reconnection be Driven by Rotational Discontinuity Downstream of Quasi-Parallel Shock?

Zhifang Guo, Yu Lin & X Wang
Ion-scale magnetic reconnection has been observed downstream of the terrestrial quasi-parallel (Q-parallel to) shock. Whether it is driven by interplanetary discontinuities or turbulent Q-parallel to shock, however, is unclear. Using three-dimensional global hybrid simulation, we investigate the generation of magnetic reconnection downstream of the Q-parallel to shock, while an interplanetary rotational discontinuity (RD) is launched to the bow shock. Cases with various solar wind Alfven Mach numbers, M-A = 3.0 to 8, and propagation directions...

Proton velocity ring-driven instabilities in the inner magnetosphere: Linear theory and particle-in-cell simulations

Kyungguk Min & Kaijun Liu
Linear dispersion theory and electromagnetic particle-in-cell (PIC) simulations are used to investigate linear growth and nonlinear saturation of the proton velocity ring-driven instabilities, namely, ion Bernstein instability and Alfven-cyclotron instability, which lead to fast magnetosonic waves and electromagnetic ion cyclotron waves in the inner magnetosphere, respectively. The proton velocity distribution is assumed to consist of 10% of a ring distribution and 90% of a low-temperature Maxwellian background. Here two cases with ring speeds v(r)/v(A)=1 and...

Fast magnetosonic waves driven by shell velocity distributions

Kyungguk Min & Kaijun Liu
Using linear dispersion theory and particle-in-cell simulations, we explore the ion Bernstein instability driven by the shell-type ion velocity distribution which is related to the excitation of fast magnetosonic waves in the terrestrial magnetosphere. We first demonstrate a novel idea to construct the shell velocity distribution out of multiple Maxwellian ring-beam velocity distributions. Applying this technique, we find that the convergence of the linear theory instability can be achieved with only a moderate number of...

Reversal of magnetic field rotation in the reconnection layer due to shear flow effects

Xiaoxia Sun, Yu Lin & Xiaogang Wang
We investigate the effects of shear flows on the so-called component reconnection, in which the guide field B-y not equal 0, by solving a one-dimensional Riemann problem for magnetopause reconnection using a resistive MHD simulation. Specifically, we consider the existence of a shear flow perpendicular to the antiparallel magnetic field B-z, while a finite shear flow tangential to B-z may also be present. In the cases without a magnetosheath flow and having thus a sheared...

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