Magnetic anisotropy and domain structure in gadolinium

The magnetocrystalline anisotropy constants of high quality single crystals of gadolinium have been measured using torque magnetometry. The redetermination of the anisotropy constants was necessary due to the poor agreement between the previous measurements which had been made on uncharacterized material of varying quality. The easy direction of magnetization was determined from the anisotropy constants and it is in good agreement with the direct measurements of Corner and Tanner (1976), made on the same crystal, and the neutron diffraction results of Cable and Wollan (1968). It is suggested that the lack of agreement in the previous determinations of the constants was due to the quality of the crystals used, particularly with respect to their oxygen content. A treatment of the magnetostatic energy of nonmagnetic inclusions in gadolinium and their contribution to the total anisotropy is given which can explain the discrepancies between the results of the various previous investigations of the easy direction and anisotropy. The magnetic domain structure of gadolinium was investigated using the Bitter wet colloid technique and a dry colloid technique suitable for low temperature work (90K to 291K). The formation of domains at the Curie temperature (291K) and also the disappearance of a clear domain structure at about 230K, below which there is an easy cone of magnetization, was observed. No magnetic domains were observed below 230K. Around 230K it was expected that there would not be a clear domain structure due to the low value of the anisotropy but the reasons for the non-appearance of domains below about 150K. where the anisotropy is large again, are not clear as Corner and Saad (19 77a) have observed clear domain patterns on gadolinium at 77K

Kinetic and mechanistic studies involving the nitroso group

Nitrosation is a major area of work in physical organic chemistry, which is of interest as an academic study in its own right but is also of wider interest owing to the carcinogenicity of some N-nitroso compounds. The present work has boon concerned with some of the reactions involving the nitroso group at nitrogen, oxygen and sulphur sites,, The approach has been to determine rate constants for the reactions involved and to use these to establish mechanism and relative reactivities. The work covers four areas; (i) Denitrosation of N-nitrosoamines in solvents other than water It has been found that some solvents do enhance the rate of denitrosation relative to that in water. (ii) Diazotisation of aromatic amines. This reaction proceeds via the formation of an N=nitroso intermediate. The relative reactivities of a number of nitrosating species in this reaction have been established. (iii) Nitrosation of thiols. Few kinetic studies have been made of S-nitrosation (compared to N-nitrosation), here the rates of reaction of some tbiocarboxylie acids toward nitrosating species have been determined and comparisons with other substrates drawn. (iv) Nitrosation of alcohols. The kinetics of nitrosation of alcohols has already been studied in some detail and here the aim has been to use this reaction to throw some light on the nature of the intermediate in aqueous nitrosation

The antecedent roles of personal constructs and culture in the construing of psychological contracts by staff in a Czech financial services company

The modern conceptualisation of the psychological contract recognises a tacit mental representation or schema, spanning all aspects of an employee’s perception of work. Reciprocity is a normative force in contract functioning. For over 500 years, the Czech Republic was subject to the rule of other nations. The failed totalitarianism of the most recent Soviet hegemony precipitated the Velvet Revolution and Czech adoption of the market economy in 1989. Some commentators have argued that unproductive work attitudes remain as a legacy of the command system. Following the phenomenological paradigm and constructivist epistemology, the research uses concepts from Personal Construct Psychology to compare the work constructs of Czech and non-Czech staff within the Czech and UK subsidiaries of the same company, examining antecedent effects of culture and individual experiences on psychological contract formation and development. The findings show that the two nationalities construe work along broadly similar lines, prioritizing its social qualities. Czech constructs seem to be simpler than those of non- Czechs, apparently lacking the value placed on personal ambition and achievement by the comparator group. Czechs do, however, appear to value independence much more than non-Czechs, with young Czechs also seemingly expecting social justice and the right to self-determination. The findings make a strong case for suggesting that these values have their origins in Czech culture and history, implying that both influence the work dispositions of Czechs and may plausibly be psychological contract antecedents. The conclusions call for a wider conceptualisation of the psychological contract, specifically in its anticipatory (pre-work) form, and suggest that existing theory might benefit from giving greater consideration and prominence to the social properties of work. Suggestions for further research and business applications are included

Whole soybeans for dairy cattle (1987)

Whole soybeans (WSB) can be used in dairy cow rations; they are palatable and have excellent feed value. WSB have lower protein content than soybean meal but because of higher fat, have higher net energy contentNew 3/87/6M

Whole soybeans for dairy cattle (1993)

Whole soybeans (WSB) can be used in dairy cow rations; they are palatable and have excellent feed value. WSB have lower protein content than soybean meal, but because of higher fat, have higher net energy content.Reviewed October 1993 -- Extension website

Mucobilia in Association With a Biliary Cystadenocarcinoma of the Caudate Duct: A Rare Cause of Malignant Biliary Obstruction

Mucobilia is a rare condition characterized by the accumulation of abundant mucus within the intra- or extrahepatic biliary tree. A variety of hepatobiliary and pancreatic neoplasms are mucin producing and have been associated with the development of mucobilia including biliary mucinosis, biliary papillomatosis, mucin-producing cholangiocarcinoma (MPCC), or cystic neoplasms of the pancreas or biliary tree (cystadenoma or cystadenocarcinoma). We report the case of 46 year-old male with a biliary cystadenocarcinoma of the caudate lobe which resulted in chronic biliary obstruction and relapsing cholangitis. A review of the literature for both mucobilia and biliary cystadenocarcinoma is provided along with a discussion addressing the clinical presentation, diagnosis, treatment, and prognosis for this rare entity

Using a microwave oven to determine moisture in forages (1993)

Harvesting and storing forage crops at the proper moisture is necessary to minimize forage losses and to maintain maximum nutritional value. But it is difficult to determine the moisture concentration of forage crops prior to ensiling or baling. This publication will discuss the method of using a microwave oven to determine moisture in forages.Barry Steevens, Ron Belyea, Richard Crawford (Department of Animal Sciences)Reviewed October 1993 -- Extension website

Forages for cattle : new methods of determining energy content and evaluating heat damage (1993)

The crude fiber method of feed analysis has been used for more than 100 years. Although this method was an important first attempt at determining the energy content of feeds, it has a number of shortcomings. A new analytical approach for estimating energy content of forages was developed by Van Soest in the 1960s at the USDA Beltsville Nutritional Research Facility. These detergent fiber analyses give more accurate estimates of forage energy values and now are used for forage analysis.Reviewed October 1993 -- Extension website

Modeling the flow of digesta through the ruminant reticulorumen

Abstract only availableRuminants possess a specialized gastrointestinal (GI) tract that enables them to efficiently digest fibrous feeds. The first stomach compartment of the ruminant GI tract, the reticulorumen (RR), is the site of most fiber digestion due to the presence of cellulolytic microorganisms in conjunction with selective retention of feed particles; undigested fibrous feed particles are selectively retained and fermented by cellulolytic microorganisms in the RR until certain digestive processes are completed, enabling the particles to pass. Selective retention and the overall process of digesta flow in the RR affect feed digestibility, feed intake, and microbial efficiency—all important animal performance parameters in ruminant production. It is imperative to model digesta flow in the RR to better predict these animal performance parameters for use in ruminant production systems. Mathematical models have indeed been developed to describe the flow of digesta in the RR, typically with the RR represented as one or more mathematical compartments with flow between compartments defined by kinetic rate variables or constants. Mathematical models developed to the present use either fractional rate constants or rate variables based on the gamma distribution. The Yule distribution has also been suggested for modeling RR digesta flow kinetics, but its development has been cursory. It remains unseen what, if any, benefits may arise from applying the Yule distribution to describe the kinetics of RR digesta. In this study, a model incorporating the Yule distribution is fully developed. Physiological justification for using the Yule distribution is also provided on the basis of selective retention. A comparison between the model developed herein and a previously published model using the gamma distribution reveals that both models give similar mathematical results under certain cases. Still, it is suggested that the physiological relevance of the model treated here may make it superior. Animal feeding trials are currently being conducted to validate the structure of model. Additionally, mathematical models are being developed to describe small and large intestinal flow in ruminant and non-ruminant species, thereby expanding this modeling effort to include most of the GI tract.Life Sciences Undergraduate Research Opportunity Progra