7,876 research outputs found
Letter from W. J. Haynes to B. R. Colson
Letter from W. J. Haynes to B. R. Colson. The one-page handwritten note is on Allen Grocery Company letterhead and is dated 31 May 1907
Family Businesses: Can the Family and the Business Finances Be Separated? Preliminary Results
Small businesses had nearly $1.25 trillion in loans outstanding from commercial lenders, business finance companies, other businesses in the form of trade credit, and friends and relatives in the early 1990s (Ou, 1991). Based on recent information derived from the National Survey on Small Business Finance (NSSBF), loans held by commercial banks and family members or owners of the firm were significant sources of credit, comprising 54 and 18 percent of all loans, respectively (Haynes, 1996). The relative importance of these types of loans suggests that the finances of the business and the family are often intertwined. This study utilizes the recently released Survey of Consumer Finances to examine the impact of small business ownership on the household’s debt structure
Flaws in Orr’s Laws (and the Paradigm that Produced Them): An Abbreviated Response
Conservation of biological diversity is often hampered by ignorance and short-sightedness. Yet knowledge is not enough; biology illuminates ecological relationships, but it alone cannot conserve ecosystems. Therefore, we agree that there is no higher priority for conservation biologists than to improve their understanding of economics (Orr 2004, Law 1). Unfortunately, from many of his comments and the tenor of subsequent responses (Hayes 2004; Vitek 2004; Lovejoy 2004), it is evident that economics and, more important, parallels between ecology and economics are misunderstood, implying the two disciplines are more different than they are and that knowledge of economics is primarily needed to enhance the appeal of ecological insight. We offer comments intended to (1) correct misunderstandings about the parallel sciences of ecology and economics; (2) present a broader perspective on efficiency, selfishness, ecological bubbles, and conditions for growth; and (3) discuss the appropriate role of science in addressing natural resource problems. Efforts to maintain ecological integrity will benefit when we abandon the erroneous assumption that ignorance and selfishness per se cause environmental problems
Modeling of intrinsic electron and hole trapping in crystalline and amorphous ZnO
Recent advances in ultrafast liquid quenching and deposition of thin films on cold substrates make growing amorphous (a)‐ZnO films increasingly feasible. The electronic structure and electron and hole trapping properties of amorphous ZnO are predicted using density functional theory (DFT) simulations with a hybrid density functional (h‐DFT). An ensemble of fifty 324‐atom structures is employed to obtain the distribution of structural and electronic properties of a‐ZnO. The results demonstrate that electrons do not localize in a‐ZnO, but holes form deep localized states with average trapping energy of about 0.9 eV. It is also shown that dispersion at the conduction band minimum (CBM) is not affected upon amorphization, suggesting that high electron mobility should be retained. An average value of a‐ZnO band gap of 3.36 eV is calculated with no states splitting into the band gap, which accounts for no substantial detrimental effect on the optical transparency upon amorphization. These findings may have important implications for future applications of a‐ZnO as a transparent conductor and photocatalyst
Total domination stable graphs upon edge addition
AbstractA set S of vertices in a graph G is a total dominating set if every vertex of G is adjacent to some vertex in S. The minimum cardinality of a total dominating set of G is the total domination number of G. A graph is total domination edge addition stable if the addition of an arbitrary edge has no effect on the total domination number. In this paper, we characterize total domination edge addition stable graphs. We determine a sharp upper bound on the total domination number of total domination edge addition stable graphs, and we determine which combinations of order and total domination number are attainable. We finish this work with an investigation of claw-free total domination edge addition stable graphs
EarthN: A new Earth System Nitrogen Model
The amount of nitrogen in the atmosphere, oceans, crust, and mantle have
important ramifications for Earth's biologic and geologic history. Despite this
importance, the history and cycling of nitrogen in the Earth system is poorly
constrained over time. For example, various models and proxies contrastingly
support atmospheric mass stasis, net outgassing, or net ingassing over time. In
addition, the amount available to and processing of nitrogen by organisms is
intricately linked with and provides feedbacks on oxygen and nutrient cycles.
To investigate the Earth system nitrogen cycle over geologic history, we have
constructed a new nitrogen cycle model: EarthN. This model is driven by mantle
cooling, links biologic nitrogen cycling to phosphate and oxygen, and
incorporates geologic and biologic fluxes. Model output is consistent with
large (2-4x) changes in atmospheric mass over time, typically indicating
atmospheric drawdown and nitrogen sequestration into the mantle and continental
crust. Critical controls on nitrogen distribution include mantle cooling
history, weathering, and the total Bulk Silicate Earth+atmosphere nitrogen
budget. Linking the nitrogen cycle to phosphorous and oxygen levels, instead of
carbon as has been previously done, provides new and more dynamic insight into
the history of nitrogen on the planet.Comment: 36 pages, 12 figure
New synchronization method for <i>Plasmodium falciparum</i>
<b>Background</b>: Plasmodium falciparum is usually asynchronous during in vitro culture. Although various synchronization methods are available, they are not able to narrow the range of ages of parasites. A newly developed method is described that allows synchronization of parasites to produce cultures with an age range as low as 30 minutes.
<b>Methods</b>: Trophozoites and schizonts are enriched using Plasmion. The enriched late stage parasites are immobilized as a monolayer onto plastic Petri dishes using concanavalin A. Uninfected erythrocytes are placed onto the monolayer for a limited time period, during which time schizonts on the monolayer rupture and the released merozoites invade the fresh erythrocytes. The overlay is then taken off into a culture flask, resulting in a highly synchronized population of parasites.
<b>Results</b>: Plasmion treatment results in a 10- to 13-fold enrichment of late stage parasites. The monolayer method results in highly synchronized cultures of parasites where invasion has occurred within a very limited time window, which can be as low as 30 minutes. The method is simple, requiring no specialized equipment and relatively cheap reagents.
<b>Conclusions</b>: The new method for parasite synchronization results in highly synchronized populations of parasites, which will be useful for studies of the parasite asexual cell cycle
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