1,447 research outputs found
Analysing the Factors that Influence Social Media Adoption Among SME's in Developing Countries
Social media penetration is on the rise in developing countries and is an important channel of growth for small and medium enterprises (SMEs). Many SMEs in developing countries use social media to connect their customers to their products and services. However, the factors that have led the existing SMEs in Africa to adopt or reject Social Media need to be clarified to understand the key contributing factors and influences at play. This paper adopts the learning-by-doing concept from economic theory to explore the factors that influence the adoption of social media. A primary survey follows this to examine the use of social media among firms in the commercial districts of Kenya and Nigeria. The preliminary surveys in both countries were combined into a single dataset to analyse the relationship between social media use and learning-by-doing.
The results show that while small SMEs are limited in their social media capacity, medium size firms tend to invest in their social media presence, and larger-size firms still rely on traditional marketing channels
AN EVALUATION OF THE PRIA GRAZING FEE FORMULA
The federal grazing fee is currently set using the Public Rangeland Improvement Act (PRIA) fee formula established in 1978 and modified in 1986. The formula is adjusted annually using indices of private land grazing lease rates (Forage Value Index, FVI), prices received for beef cattle (Beef Cattle Price Index, BCPI), and costs of beef production (Prices Paid Index, PPI). The FVI tracks price movement in the private forage market and was the only index originally proposed to be included in the fee formula. Public land ranchers and an Interdepartmental Grazing Fee Technical Committee assigned to study grazing fee alternatives in the 1960s questioned the ability of the FVI to account for short-term demand, supply, and price equilibrium, and, for this reason, the BCPI and PPI were added to the fee formula. Over 30 years of data are now available to evaluate whether adding the BCPI and PPI did, in fact, help explain short-term market fluctuations. This analysis shows, as earlier studies did, that, if tracking the private forage market is the primary objective, then the fee formula should have included only the FVI. Including the BCPI and, especially, the PPI has caused calculated grazing fees to fall further and further behind private land lease rates. Had the 3.84/AUM instead of $1.35/AUM in 2000. It is time to consider the feasibility of a competitive bid system for public lands, or, at the very least, adopt a new fee formula that generates more equitable grazing fees.Land Economics/Use,
Proceedings of the 48th Annual Meeting, Southern Soybean Disease Workers (March 3, 2021, Virtual Content)
2021 Southern Soybean Disease Workers Agenda
Virtual | Wednesday, March 3, 2021
Southern United States Soybean Disease Loss Estimates for 2020. TW Allen, K Bissonnette, CA Bradley, JP Damicone, NS Dufault, TR Faske, T Isakeit, RC Kemerait, A Koehler, D Langston, JD Mueller, GB Padgett, PP Price, EJ Sikora, IM Small, L Thiessen, and H Young
Student papers (Tessie Wilkerson, moderator)
Secondary metabolites produced by Xylaria necrophora are responsible for the foliar symptoms associated with taproot decline of soybean. Teddy Garcia-Aroca, Trey Price, José Solórzano, David Galo, Sophie Sheffield, Jonathan K. Richards, and Vinson P. Doyle
Meta-analysis of fungicide performance for managing frogeye leaf spot on soybean in the United States. Jhonatan P Barro, Emerson M Del Ponte, Tom Allen, Jason P Bond, Travis R Faske, Clayton A Hollier, Yuba R Kandel, Daren S Mueller, Heather M Kelly, Nathan M Kleczewski, Paul Price, Edward J Sikora, and Carl A Bradley
Using metagenomic tools to explore the suppression of soybean cyst nematode populations in fields double-cropped with wheat and soybean. Leonardo F Rocha, Jason P Bond, Ahmad M Fakhoury
Investigating the effects of demethylation inhibitor fungicides and the insecticide malathion on Corynespora cassiicola. Ty Smith, Heather Kelly, and Larry Steckel
DNA-based protocol for rapid detection of QoI (Strobilurin) fungicide resistance in Cercospora sojina and a statewide survey of foliar fungicide use for soybean disease management in Nebraska. Asha Mane, Tamra Jackson-Ziems, Carl Bradley, and Syndney Everhart
Assessing Missouri soybean fields for fungicide-resistant Cercospora sojina. Bruna Just, and Kaitlyn M Bissonnette
Contributed papers (Trey Price, moderator)
Observations from soybean rust monitoring and fungicide field demonstrations in Alabama in 2020. Edward J Sikora and Kassie Conner
Field performance of two new commercially available premix fungicides for management of foliar disease of soybean in Arkansas. Terry N Spurlock, Robert C Hoyle, Sydney F Kling, and Amanda C Tolbert
The impact of different crop rotations on soilborne microbial diversity and disease emergence of soybean-corn cropping system. Qiurong Fan, Travis Faske, Terry Spurlock, Alejandro Rojas and Trent Roberts
SCN Coalition: Updates and Evolution. Sam Markell and Albert Tenuta
Evaluating varieties in the Mississippi State University Official Variety Trial Program for the presence and severity of green stem. Tom Allen, Walter Solomon, and Brad Burgess
Proceedings of the Southern Soybean Disease Workers are published annually by the Southern Soybean Disease Workers. Text, references, figures, and tables are reproduced as they were submitted by authors. The opinions expressed by the participants at this conference are their own and do not necessarily represent those of the Southern Soybean Workers. Mention of a trademark or proprietary products in this publication does not constitute a guarantee, warranty, or endorsement of that product by the Southern Soybean Disease Workers
Proceedings of the 47th Annual Meeting, Southern Soybean Disease Workers (March 4-5, 2020, Pensacola Beach, Florida)
Contents
Southern United States soybean disease loss estimates for 2019. TW Allen, K Bissonnette, CA Bradley, JP Damicone, NS Dufault, TR Faske, T Isakeit, RC Kemerait, A Koehler, HL Mehl, JD Mueller, GB Padgett, PP Price, EJ Sikora, IM Small, L Thiessen, and H Young
Abstracts of presented papers
Fungicide efficacy on target spot in Tennessee soybean. Ty Smith, H Kelly, and Z Hansen
Temporal dynamics of Neohydatothrips variabilis, Frankliniella tritici, and Frankliniella fusca in South Central Wisconsin and the occurrence of Soybean vein necrosis virus. Cristina Zambrana-Echevarria, S Kaplan, RL Groves, and DL Smith
Population distributions and densities of nematodes, and virulence phenotypes of soybean cyst nematode in Tennessee. Rufus Akinrinlola, and H Kelly
Improving soybean white mold control by integrated management. Wade Webster, B Mueller, J Gaska, D Mueller, MI Chilvers, S Conley, and DL Smith
Assessment of QoI sensitivity and frogeye leaf spot race of Cercospora sojina in Georgia soybean. Bennett Harrelson, A Culbreath, R Kemerait, Jr, and J Buck
Reduction of Pythium damping-off in soybean by biocontrol seed treatment. Mirian F Pimentel, E Arnao, A Warner, N Elsharif, M Chilvers, A Robertson, J Bond, and A Fakhoury
Understanding cercosporin self-resistance to identify novel tools to manage Cercospora leaf blight on soybean. Maria Izabel Costa de Novaes, CL Robertson, VP Doyle, and S Thomas-Sharma
Evaluating the efficacy of soybean seed treatment on high and low vigor seed in Arkansas. Samantha Segalin, JC Rupe, JA Rojas, and R Holland
Impact of wheat on soybean cyst nematode (Heterodera glycines I.) populations in a soybean double cropping system. Leonardo F Rocha, MF Pimentel, JP Bond, and AM Fakhoury
Using unmanned aerial systems and multispectral imagery to assess sudden death syndrome of soybean. Lindsey McKinzie, AM Fakhoury, R Li, and JP Bond
Soybean rust: Scourge of Alabama. Ed J Sikora, D Delaney, and K Connor
Management of SCN and SDS with nematode-protectant seed treatments across multiple environments. Kaitlyn M Bissonnette, Y Kandel, M Chilvers, N Kleczewski, D Mueller, D Smith, D Telenko, and A Tenuta
Determining inoculum density of Xylaria sp., the taproot decline pathogen, in soil under various crop rotation systems. Aline Bronzato-Badial, K Phillips, TH Wilkerson, and M Tomas-Peterson
A new pathosystem to study the plant-fungal interactions underlying Cercospora leaf blight of soybean. Kona Swift and B Bluhm
Impact of cultivar on soybean foliar and seed diseases in Arkansas. John C Rupe, RT Holland, and JA Rojas
Thoughts on southern blight: Should we be concerned about southern blight? Tom W Allen, WL Solomon, and BA Burgess
From plots to strips: Six years of fungicide trials. Terry N Spurlock, AC Tolbert, and RC Hoyle
Meta-analysis of soybean yield response to foliar fungicides evaluated from 2005 to 2018 in the United States and Canada. Yuba K Kandel, C Hunt, K Ames, N Arneson, CA Bradley, E Byamukama, A Byrne, MI Chilvers, L Giesler, J Halvorson, DC Hooker, NM Kleczewski, DK Malvick, S Markell, B Potter, W Pederson, DL Smith, AU Tenuta, DEP Telenko, KA Wise, and DS Mueller
On the road in Louisiana: Taking the research station to farms. Trey Price, MA Purvis, DA Ezell, GB Padgett, M Foster, and J Hebert
The next super model: Development of a flexible framework for multiple disease models in soybean. Damon L Smith, J Willbur, M Chilvers, M Kabbage, SP Conley, D Mueller, and R Schmidt
IPM implementation in Tennessee. Heather M Kelly, S Stewart, K Vail, D Hensley, S Steckel, A McClure, and T Raper
Reproduction potential and survival of soybean nematodes in row rice. Travis Faske, K Brown, and N Bateman
Initial research with peracetic acid as a disease management tool in soybeans and other legume crops. Vijay K Choppakatla
FMC fungicide offerings update. Matthew Wiggins
Abstracts for presented posters
Extension efforts in disseminating nematode survey results. Rachel Guyer, R Akinrinlola, and H Young
Assessing the role of weathering on the grain quality of soybean varieties in the Mississippi Delta. Tessie H Wilkerson, TW Allen, and BA Burgess
Proceedings of the Southern Soybean Disease Workers are published annually by the Southern Soybean Disease Workers.
Text, references, figures, and tables are reproduced as they were submitted by authors. The opinions expressed by the participants at this conference are their own and do not necessarily represent those of the Southern Soybean Workers.
Mention of a trademark or proprietary products in this publication does not constitute a guarantee, warranty, or endorsement of that product by the Southern Soybean Disease Workers
SPITZER: Accretion in Low Mass Stars and Brown Dwarfs in the Lambda Orionis Cluster
We present multi-wavelength optical and infrared photometry of 170 previously
known low mass stars and brown dwarfs of the 5 Myr Collinder 69 cluster (Lambda
Orionis). The new photometry supports cluster membership for most of them, with
less than 15% of the previous candidates identified as probable non-members.
The near infrared photometry allows us to identify stars with IR excesses, and
we find that the Class II population is very large, around 25% for stars (in
the spectral range M0 - M6.5) and 40% for brown dwarfs, down to 0.04 Msun,
despite the fact that the H(alpha) equivalent width is low for a significant
fraction of them. In addition, there are a number of substellar objects,
classified as Class III, that have optically thin disks. The Class II members
are distributed in an inhomogeneous way, lying preferentially in a filament
running toward the south-east. The IR excesses for the Collinder 69 members
range from pure Class II (flat or nearly flat spectra longward of 1 micron), to
transition disks with no near-IR excess but excesses beginning within the IRAC
wavelength range, to two stars with excess only detected at 24 micron.
Collinder 69 thus appears to be at an age where it provides a natural
laboratory for the study of primordial disks and their dissipation.Comment: ApJ, in pres
Dissecting the Economic Impact of Soybean Diseases in the United States over Two Decades
Soybean (Glycine max L. Merrill) is an economically important commodity for United States agriculture. Nonetheless, the profitability of soybean production has been negatively impacted by soybean diseases. The economic impacts of 23 common soybean diseases were estimated in 28 soybean-producing states in the U.S., from 1996 to 2016 (the entire data set consisted of 13,524 data points). Estimated losses were investigated using a variety of statistical approaches. The main effects of state, year, pre- and post-discovery of soybean rust, region, and zones based on yield, harvest area, and production, were significant on “total economic loss” as a function of diseases. Across states and years, the soybean cyst nematode, charcoal rot, and seedling diseases were the most economically damaging diseases while soybean rust, bacterial blight, and southern blight were the least economically damaging. A significantly greater mean loss (51%) was observed in states/years after the discovery of soybean rust (2004 to 2016) compared to the pre-discovery (1996 to 2003). From 1996 to 2016, the total estimated economic loss due to soybean diseases in the U.S. was 80.89 billion and 4.55 billion, with approximately 85% of the losses occurring in the northern U.S. Low yield/harvest/production zones had significantly lower mean economic losses due to diseases in comparison to high yield/harvest/production zones. This observation was further bolstered by the observed positive linear correlation of mean soybean yield loss (in each state, due to all diseases considered in this study, across 21 years) with the mean state wide soybean production (MT), mean soybean yield (kg ha-1), and mean soybean harvest area (ha). Results of this investigation provide useful insights into how research, policy, and educational efforts should be prioritized in soybean disease management
Light scattering from three-level systems: The T-matrix of a point-dipole with gain
We present an extension of the T-matrix approach to scattering of light by a
three-level system, using a description based on a Master equation. More
particularly, we apply our formalism to calculate the T-matrix of a pumped
three-level atom, providing an exact and analytical expression describing the
influence of a pump on the light scattering properties of an atomic three-level
system
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Modelling the effects of gravity waves on stratocumulus clouds observed during VOCALS-UK
During the VOCALS campaign spaceborne satellite observations showed that travelling gravity wave packets, generated by geostrophic adjustment, resulted in perturbations to marine boundary layer (MBL) clouds over the south-east Pacific Ocean (SEP). Often, these perturbations were reversible in that passage of the wave resulted in the clouds becoming brighter (in the wave crest), then darker (in the wave trough) and subsequently recovering their properties after the passage of the wave. However, occasionally the wave packets triggered irreversible changes to the clouds, which transformed from closed mesoscale cellular convection to open form. In this paper we use large eddy simulation (LES) to examine the physical mechanisms that cause this transition. Specifically, we examine whether the clearing of the cloud is due to (i) the wave causing additional cloud-top entrainment of warm, dry air or (ii) whether the additional condensation of liquid water onto the existing drops and the subsequent formation of drizzle are the important mechanisms. We find that, although the wave does cause additional drizzle formation, this is not the reason for the persistent clearing of the cloud; rather it is the additional entrainment of warm, dry air into the cloud followed by a reduction in longwave cooling, although this only has a significant effect when the cloud is starting to decouple from the boundary layer. The result in this case is a change from a stratocumulus to a more patchy cloud regime. For the simulations presented here, cloud condensation nuclei (CCN) scavenging did not play an important role in the clearing of the cloud. The results have implications for understanding transitions between the different cellular regimes in marine boundary layer (MBL) clouds
Modeling the Relationship Between Estimated Fungicide Use and Disease-Associated Yield Losses of Soybean in the United States I: Foliar Fungicides vs Foliar Diseases
Fungicide use in the United States to manage soybean diseases has increased in recent years. The ability of fungicides to reduce disease-associated yield losses varies greatly depending on multiple factors. Nonetheless, historical data are useful to understand the broad sense and long-term trends related to fungicide use practices. In the current study, the relationship between estimated soybean yield losses due to selected foliar diseases and foliar fungicide use was investigated using annual data from 28 soybean growing states over the period of 2005 to 2015. For national and regional (southern and northern United States) scale data, mixed effects modeling was performed considering fungicide use as a fixed and state and year as random factors to generate generalized R2 values for marginal (R2GLMM(m); contains only fixed effects) and conditional (R2GLMM(c); contains fixed and random effects) models. Similar analyses were performed considering soybean production data to see how fungicide use affected production. Analyses at both national and regional scales showed that R2GLMM(m) values were significantly smaller compared to R2GLMM(c) values. The large difference between R2 values for conditional and marginal models indicated that the variation of yield loss as well as production were predominantly explained by the state and year rather than the fungicide use, revealing the general lack of fit between fungicide use and yield loss/production at national and regional scales. Therefore, regression models were fitted across states and years to examine their importance in combination with fungicide use on yield loss or yield. In the majority of cases, the relationship was nonsignificant. However, the relationship between soybean yield and fungicide use was significant and positive for majority of the years in the study. Results suggest that foliar fungicides conferred yield benefits in most of the years in the study. Furthermore, the year-dependent usefulness of foliar fungicides in mitigating soybean yield losses suggested the possible influence of temporally fluctuating abiotic factors on the effectiveness of foliar fungicides and/or target disease occurrence and associated loss magnitudes
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