7,094 research outputs found
Agricultural Carbon and Greenhouse Gases: Moving to Markets
Environmental Economics and Policy,
A terminal molybdenum carbide prepared by methylidyne deprotonation
The carbide anion [CMo{N(R)Ar}_3]– [R = C(CD_3)_2CH_3, Ar = C_6H_3Me_2-3,5], is obtained by deprotonation of the corresponding methylidyne compound, [HCMo{N(R)Ar}_3], and is characterized by X-ray diffraction as its {K(benzo-15-crown-5)_2}+ salt, thereby providing precedent for the carbon atom as a terminal substituent in transition-metal chemistry
Partial Characterization of the Extracellular Polysaccharides Produced by Mutants of Rhizobium leguminosarum and Rhizobium trifolii
Extracellular polysaccharides (EPS) are suspected to be involved in some aspect of the Rhizobium-legume symbiotic process. Extracellular polysaccharides produced by R. leguminosarum and R. trifolii mutants were isolated and partially characterized by gas chromatography, column chromatography, double diffusion, polyacrylamide gel electrophoresis, and immunoelectrophoresis.
The R. leguminosarum mutants, derived from strain 128C53, all are deficient in EPS production (exo-). Strain ANU54 is missing the symbiotic plasmid, while plasmid-containing strains ANU54 pJB5JI and ANU54 pBR1AN nodulate (nod+) peas and clover respectively, but do not fix nitrogen (fix-).
R. leguminosarum mutants produce an EPS that is similar to parental LPS in composition. Double diffusion studies indicate that all mutant LPS and EPS are antigenically identical. Both plasmid-containing mutants show an extra precipitin line in double diffusion analysis and unique antibody-binding bands when subjected to immunoelectrophoresis.
R. trifolii ANU794 produces normal amounts of EPS (exo+) and carries on normal symbiosis with clover. ANU437 (nod+ fix-exo-), is a Tn5 mutant of ANU794, but the insertion is not in the symbiotic plasmid. Strain ANU437RP4 (nod+ fix+,exo+) is strain ANU437 which has been complimented with a 4kb region from a wild-type R. trifolii.
ANU437 produces an EPS that has a sugar composition similar to parental LPS. The 4kb insertion contained in ANU437RP4 restores the production of normal amounts of EPS that is similar in composition to parental EPS.
Other R. trifolii mutants studied are affected in their ability to cause root hair curling. Strains ANU262 and ANU258 have a Tn5 insertion in the symbiotic plasmid, and cause severe root hair curling (hac++), but ANU258 is also affected in that it now has an increased host range.
Purification of LPS by Sepharose 4B column chromatography revealed that the void and included volumes of strains ANU258 and ANU262 contain KDO and heptose, while parental strain ANU843 did not. The pyruvate level is lower in the LPS from ANU258 than in the LPS from ANU262. Double diffusion studies indicate that LPS from ANU258 and ANU262 is antigenically identical to the parental LPS and to LPS from mutants that do not cause root hair curling. The EPS composition of ANU258 and ANU262 is similar to strain ANU843.
This study suggests that same small molecular weight molecules produced by plasmid-containing mutants of R. leguminosarum may have a role in the formation of nodules. Studies of R. trifolii EPS indicate that EPS may be important in the formation of effective nodules, but not in causing extreme root hair curling. Preliminary studies of LPS from mutants affected in root hair curling suggest that some differences exist in pyruvate levels and composition of Sepharose 4B peaks
Partial Characterization of the Extracellular Polysaccharides Produced by Mutants of Rhizobium leguminosarum and Rhizobium trifolii
Extracellular polysaccharides (EPS) are suspected to be involved in some aspect of the Rhizobium-legume symbiotic process. Extracellular polysaccharides produced by R. leguminosarum and R. trifolii mutants were isolated and partially characterized by gas chromatography, column chromatography, double diffusion, polyacrylamide gel electrophoresis, and immunoelectrophoresis.
The R. leguminosarum mutants, derived from strain 128C53, all are deficient in EPS production (exo-). Strain ANU54 is missing the symbiotic plasmid, while plasmid-containing strains ANU54 pJB5JI and ANU54 pBR1AN nodulate (nod+) peas and clover respectively, but do not fix nitrogen (fix-).
R. leguminosarum mutants produce an EPS that is similar to parental LPS in composition. Double diffusion studies indicate that all mutant LPS and EPS are antigenically identical. Both plasmid-containing mutants show an extra precipitin line in double diffusion analysis and unique antibody-binding bands when subjected to immunoelectrophoresis.
R. trifolii ANU794 produces normal amounts of EPS (exo+) and carries on normal symbiosis with clover. ANU437 (nod+ fix-exo-), is a Tn5 mutant of ANU794, but the insertion is not in the symbiotic plasmid. Strain ANU437RP4 (nod+ fix+,exo+) is strain ANU437 which has been complimented with a 4kb region from a wild-type R. trifolii.
ANU437 produces an EPS that has a sugar composition similar to parental LPS. The 4kb insertion contained in ANU437RP4 restores the production of normal amounts of EPS that is similar in composition to parental EPS.
Other R. trifolii mutants studied are affected in their ability to cause root hair curling. Strains ANU262 and ANU258 have a Tn5 insertion in the symbiotic plasmid, and cause severe root hair curling (hac++), but ANU258 is also affected in that it now has an increased host range.
Purification of LPS by Sepharose 4B column chromatography revealed that the void and included volumes of strains ANU258 and ANU262 contain KDO and heptose, while parental strain ANU843 did not. The pyruvate level is lower in the LPS from ANU258 than in the LPS from ANU262. Double diffusion studies indicate that LPS from ANU258 and ANU262 is antigenically identical to the parental LPS and to LPS from mutants that do not cause root hair curling. The EPS composition of ANU258 and ANU262 is similar to strain ANU843.
This study suggests that same small molecular weight molecules produced by plasmid-containing mutants of R. leguminosarum may have a role in the formation of nodules. Studies of R. trifolii EPS indicate that EPS may be important in the formation of effective nodules, but not in causing extreme root hair curling. Preliminary studies of LPS from mutants affected in root hair curling suggest that some differences exist in pyruvate levels and composition of Sepharose 4B peaks
Distribution payout practices and the collapse of A-REITs
In the lead up to the Global Financial Crisis, A-REITS pursued aggressive distribution practices. Payout ratios significantly in excess of 100% of underlying earnings became common place, funded largely from increased borrowings. The GFC painfully exposed the unsustainability of this practice. A-REITs were punished when the global debt markets froze and property values crashed, leading to massive equity destruction for over geared A- REITs.This research explores the pre-GFC distributions practices of A- REITs. Annual report financial data analysis and semi-structured interviews with five industry experts were conducted to examine A-REIT distribution practices. The results reveal a clear systematic decline in the relationship between underlying earnings and distributions. It is further discovered that the since abandoned practice of distributing un-realised profits was designed to boost share prices. Paradoxically, it eventually led to their decline and the A-REIT sector's demise
Generating-function method for fusion rules
This is the second of two articles devoted to an exposition of the
generating-function method for computing fusion rules in affine Lie algebras.
The present paper focuses on fusion rules, using the machinery developed for
tensor products in the companion article. Although the Kac-Walton algorithm
provides a method for constructing a fusion generating function from the
corresponding tensor-product generating function, we describe a more powerful
approach which starts by first defining the set of fusion elementary couplings
from a natural extension of the set of tensor-product elementary couplings. A
set of inequalities involving the level are derived from this set using Farkas'
lemma. These inequalities, taken in conjunction with the inequalities defining
the tensor products, define what we call the fusion basis. Given this basis,
the machinery of our previous paper may be applied to construct the fusion
generating function. New generating functions for sp(4) and su(4), together
with a closed form expression for their threshold levels are presented.Comment: Harvmac (b mode : 47 p) and Pictex; to appear in J. Math. Phy
Employee Motivation
Currently in the state of Nebraska, there is a shortage of agricultural workers. As Nebraska’s population continues to move east, and the size of grain and livestock operations continue to increase, finding and retaining employees will become a necessity for more agricultural producers. Research is being conducted at the University of Nebraska to improve the leadership skills of producers. Even though there are many skills successful leaders need to have, one of the most important is being able to motivate your employees. A recent study looked at the relationship between an employee’s source of motivation and the type of behaviors they demonstrate while at work. This study has helped us to better understand what motivates agricultural workers in the state of Nebraska and allows us to make suggestions to employers on how to effectively motivate their employees. In the following paragraphs the results of this study and the implications for producers will be discussed
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