786 research outputs found
FARM MACHINERY INVESTMENT AND THE TAX REFORM ACT OF 1986
The Tax Reform Act of 1986 significantly changed incentives for investing. This analysis specifically examines how changes in marginal tax rates, depreciation schedules, and the investment tax credit altered the cost of capital and net investment in agriculture. A stochastic coefficients econometric methodology is used to estimate an investment function which is then used to simulate the effects of tax reform. Estimates indicated that relative to prior law, the Tax Reform Act will reduce the capital stock of farm machinery and equipment by nearly $4 billion.Agricultural Finance, Farm Management,
In Memoriam: From cotton farming to the Congressional Gold Medal: the career and legacy of Ernest James Harris (1928-2018)
Aggregation properties of mycolic acid molecules in monolayer films: a comparative study of compounds from various acid-fast bacterial species
AbstractThree kinds of mycolic acids (MAs) (α-, keto and methoxy-MAs) extracted from several species of mycobacteria were used to prepare monolayer films on water, and the surface pressure–area (π–A) isotherms of the monolayers have been compared, so that the monolayer characteristics of the MAs as in cell walls would be revealed, since the monolayer molecular aggregation is related to drug permeability via the molecular packing. It was expected that the limiting molecular areas of the isotherms would be changed only a little, which reflects the minor difference in chemical structure and conformation of the mycobacteria. Nevertheless, the results are largely different from the expectation, and two greatly different patterns of the limiting molecular area have been observed. In a new model for elucidation of the results, two parts in an MA molecule are separately considered, and both contributions to the molecular unfolding by the monolayer compression have been suggested. This model is found to be useful to totally understand the isotherm behaviors of MAs. The relationship between monolayer properties and chemical structures for MAs has been summarized for the first time
A resorcinarene for inhibition of Aβ fibrillation.
Amyloid-β peptides (Aβ) fibrillation is the hallmark of Alzheimer's disease (AD). However, it has been challenging to discover potent agents in order to inhibit Aβ fibrillation. Herein, we demonstrated the effect of resorcinarene on inhibiting Aβ fibrillation in vitro via experimental and computational methods. Aβ were incubated with different concentrations of resorcinarene so as to monitor the kinetics by using thioflavin T binding assay. The results, which were further confirmed by far-UV CD spectroscopy and atomic force microscopy, strongly indicated that the higher concentration of resorcinarene, the more effective the inhibition of Aβ fibrillation. A cytotoxicity study showed that when sea urchin embryos were exposed to the resorcinarene, the majority survived due to the resorcinarene low toxicity. In addition, when the resorcinarene was added, the formation of toxic Aβ 42 species was delayed. Computational studies of Aβ fibrillation, including docking simulations and MD simulations, illustrated that the interaction between inhibitor resorcinarene and Aβ is driven by the non-polar interactions. These studies display a novel strategy for the exploration of promising antiamyloiddogenic agents for AD treatments
The Influence of Topology on Hydraulic Conductivity in a Sand-and-Gravel Aquifer
A field experiment consisting of geophysical logging and tracer testing was conducted in a single well that penetrated a sand-and-gravel aquifer at the U.S. Geological Survey Toxic Substances Hydrology research site on Cape Cod, Massachusetts. Geophysical logs and flowmeter/pumping measurements were obtained to estimate vertical profiles of porosity ϕ, hydraulic conductivity K, temperature, and bulk electrical conductivity under background, freshwater conditions. Saline-tracer fluid was then injected into the well for 2 h and its radial migration into the surrounding deposits was monitored by recording an electromagnetic-induction log every 10 min. The field data are analyzed and interpreted primarily through the use of Archie’s (1942) law to investigate the role of topological factors such as pore geometry and connectivity, and grain size and packing configuration in regulating fluid flow through these coarse-grained materials. The logs reveal no significant correlation between K and ϕ, and imply that groundwater models that link these two properties may not be useful at this site. Rather, it is the distribution and connectivity of the fluid phase as defined by formation factor F, cementation index m, and tortuosity α that primarily control the hydraulic conductivity. Results show that F correlates well with K, thereby indicating that induction logs provide qualitative information on the distribution of hydraulic conductivity. A comparison of α, which incorporates porosity data, with K produces only a slightly better correlation and further emphasizes the weak influence of the bulk value of ϕ on K
The Influence of Topology on Hydraulic Conductivity in a Sand-and-Gravel Aquifer
A field experiment consisting of geophysical logging and tracer testing was conducted in a single well that penetrated a sand-and-gravel aquifer at the U.S. Geological Survey Toxic Substances Hydrology research site on Cape Cod, Massachusetts. Geophysical logs and flowmeter/pumping measurements were obtained to estimate vertical profiles of porosity ϕ, hydraulic conductivity K, temperature, and bulk electrical conductivity under background, freshwater conditions. Saline-tracer fluid was then injected into the well for 2 h and its radial migration into the surrounding deposits was monitored by recording an electromagnetic-induction log every 10 min. The field data are analyzed and interpreted primarily through the use of Archie’s (1942) law to investigate the role of topological factors such as pore geometry and connectivity, and grain size and packing configuration in regulating fluid flow through these coarse-grained materials. The logs reveal no significant correlation between K and ϕ, and imply that groundwater models that link these two properties may not be useful at this site. Rather, it is the distribution and connectivity of the fluid phase as defined by formation factor F, cementation index m, and tortuosity α that primarily control the hydraulic conductivity. Results show that F correlates well with K, thereby indicating that induction logs provide qualitative information on the distribution of hydraulic conductivity. A comparison of α, which incorporates porosity data, with K produces only a slightly better correlation and further emphasizes the weak influence of the bulk value of ϕ on K
Visualization of artificial lignin supramolecular structures
In this paper we are presenting the results of our environmental scanning electron microscopy (ESEM) investigation of the lignin model compound-enzymatically polymerized coniferyl alcohol, also known as dehydrogenate polymer (DHP). The goals of this study were to visualize the supramolecular organization of DHP polymer on various substrates, namely graphite, mica, and glass, and to explore the influence of substrate surface properties and associated collective phenomena on the lignin self-assembled supramolecular structure. Based on results obtained with ESEM, combined with previously published results based on scanning tunneling microscopy (STM) and electron spin resonance (ESR) technique, we looked at Lignin structure ranging from a monomer on a fraction of nanometer scale to a large aggregate on a fraction of millimeter scale. therefore using six orders of magnitude range of size. Herein, we are presenting evidence that there are at least four different levels of the supramolecular structure of lignin, and that its supramolecular organization is well dependent on the substrate surface characteristics, such as hydrophobicity, delocalized orbitals, and surface-free entry
Rearing Fopius arisanus (Sonan) (Hymenoptera: Braconidae) on Mediterranean Fruit Fly and its Introduction into Senegal against Oriental Fruit Fly (Diptera: Tephritidae)
Oriental fruit fly, Bactrocera dorsalis (Hendel) (aka B. invadens Drew, Tsuruta, and White), a serious pest of tropical fruits, particularly mango, was first reported in Africa in 2003 and quickly spread to over 27 countries. In the parasitoid introduction reported herein, Fopius arisanus (Sonan) was reared on and shipped to Senegal inside pupae of Mediterranean fruit fly, Ceratitis capitata (Wiedemann), which is endemic to Africa, rather than its usual B. dorsalis host, because B. invadens was still treated as a separate species from B. dorsalis in 2012, and to avoid the risk of fly escape from unparasitized pupae in the shipment. From 2013 to 2014, 14 shipments, totaling approximately 246,000 F. arisanus, were sent from Hilo, HI, USA to Dakar, Senegal and released in 12 mango and orange orchards in the Casamance region of southern Senegal. Parasitoids were emerged from pupae, processed and small scale rearing done on locally available B. dorsalis for subsequent releases. Limited numbers of F. arisanus had also been released in 2012 from cultures maintained in Cotonou, Benin, by IITA under the PADERCA project, but parasitism was relatively low. During 2013 and 2014 parasitism rate in mango fruits has steadily increased to 20–25%. Based on this technique, a similar approach has been used for introduction of F. arisanus against carambola fruit fly, Bactrocera carambolae Drew & Hancock, into Brazil
Determine both the conformation and orientation of a specific residue in α-synuclein(61–95) even in monolayer by ¹³C isotopic label and p-polarized multiple-angle incidence resolution spectrometry (pMAIRS)
Protein’s magic function stems from its structure and various analytical techniques have been developed for it. Among proteins, membrane proteins are encoded 20–30% of genomes, whereas cause challenges for many analytical techniques. For example, lots of membrane proteins cannot form single crystal structure required by X-ray crystallography. As for NMR, the measurements were hindered by the low tumbling rates of membrane (i.e., phospholipid bilayers) where membrane proteins exist. In addition, membrane proteins usually lay parallel to the surface of phospholipid bilayers or form transmembrane structure. No matter parallel or perpendicular to phospholipid bilayers surface, membrane proteins form monolayer structure which is also difficult for X-ray and NMR to provide high-resolution results. Because NMR and X-ray crystallography are the two major analytical techniques to address protein’s structure, membrane proteins only contribute 2.4% to the solved protein databank. Surface FT-IR techniques can evaluate the conformation and orientation of membrane proteins by amide I band. Specifically for α-helical peptides/proteins, the orientation of the axis is critical to decide whether proteins form transmembrane structure. Notice that the traditional FT-IR can only provide “low-resolution” results. Here, ¹³C isotope was introduced into the nonamyloid component (NAC), which spans residues 61–95 of α-synuclein (α-syn). Then, p-polarized multiple-angle incidence resolution spectrometry (pMAIRS) was used to determine the orientation of a specific residue of α-helical NAC in monolayer. In general, pMAIRS is a novel technique to work complementary with X-ray and NMR to address membrane peptides/proteins structure with high resolution even in monolayer
Myo-Inositol and phytate are toxic to Formosan subterranean termites (Isoptera: Rhinotermitidae)
© 2014 Entomological Society of America. Several rare and common monosaccharides were screened for toxic effects on the Formosan subterranean termite, Coptotermes formosanus Shiraki, with the aim of identifying environmentally friendly termiticides. myo-Inositol and phytic acid, which are nontoxic to mammals, were identified as potential termite control compounds. Feeding bioassays with termite workers, where both compounds were supplied on filter paper in concentrations from 160.2 to 1,281.7μg/mm3, showed concentration-dependent toxicity within 2 wk. Interestingly myo-inositol was nontoxic when administered to termites in agar (40 mg/ml) in the absence of a cellulosic food source, an unexplained phenomenon. In addition, decreased populations of termite hindgut protozoa were observed upon feeding on myo-inositol but not phytate-spiked filter paper. Radiotracer feeding studies using myoinositol-[ 2-3H] with worker termites showed no metabolism after ingestion over a 2-d feeding period, ruling out metabolites responsible for the selective toxicity
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