6,201 research outputs found
On surface subgroups of doubles of free groups
We give several sufficient conditions for a double of a free group along a
cyclic subgroup to contain a surface subgroup.Comment: 21 pages, 1 figur
CONTRACT MARKET VIABILITY
Academia and the finance industry generate many proposals for new contract markets. Unfortunately, many proposed markets lack the critical attributes that promote success. We examine these attributes, and evaluate the potential of several announced proposals. We find that proposals emanating from the academy generally fail to consider the full suite of integrated financial services necessary to support a viable market, while proposals put forward by practitioners are much more likely to do so.Marketing,
Stress and Fetal Lung Maturity
It has been the clinical impression for many years that certain 'stressful' pregnancy complications appear to be associated with a generally improved neonatal outcome. The reason for this is unclear but is has been proposed that a hostile intrauterine environment may, perhaps as a result of relative hypoxia, promote the release of hormones such as cortisol and catecholamines. These hormones may facilitate the maturational processes, particularly in the lung, and so help to prepare the fetus for extrauterine life. Certainly, and despite advances in neonatal care, respiratory problems remain the most common cause of death in normally-formed live-born babies (Chamberlain et al 1975), being responsible for about 1500 deaths in England and Wales alone in 1980 (HMSO 1980). Even if the baby survives, however, the need for prolonged ventilatory support may lead to the development of bronchopulmonary dysplasia and other causes of chronic respiratory insufficiency (Levine and Dubowitz 1982, Tarrow-Mordi and Wilkinson 1986). Other problems such as intraventricular haemorrhage, patent ductus arteriosus and pneumothorax are also related to respiratory immaturity (Greenhough and Roberton 1985, Whittle et al 1986). The improvements in neonatal care have resulted in survival rates of over 88% for babies weighing greater than 1000 g in some units (Greenhough and Roberton 1985). In view of the excellent survival rates for the small baby, the obstetrician when faced with a difficult management problem not unnaturally has a low threshold for preterm delivery often, as is increasingly the trend, without prior assessment of fetal lung maturity. With more and more small babies receiving assisted ventilation, knowledge of the natural development of the respiratory system in the human fetus is essential. The aims of this thesis were: 1. To evaluate certain obstetric factors, considered to influence fetal lung maturity. 2. To investigate what controls respiratory maturity in the human fetus. 3. To evaluate human fetal adrenal cortisol and medullary activity from mid-trimester until term. The basis of the study centres on the concept of fetal stress in utero being the interlinking factor between the various obstetric problems and fetal lung maturity. However, many of the current ideas regarding human fetal lung development have been derived from animal experiments, the results of which may not be applicable to the human. A timetable of events can, however, be defined using a combination of animal and human data and a review of the current literature is contained in Chapters 2 and 3. Chapter 2 outlines what is currently known of the normal development of the human fetal lung. The anatomical, physiological and biochemical development are discussed and the evidence presented suggesting an important role for the fetal stress hormones cortisol and the catecholamines. A number of animal studies have suggested that corticosteroids can cause an induction of the enzymes involved in surfactant synthesis and that the catecholamines, especially adrenaline, facilitate the release of surfactant (the surface-active lung phospholipids) and the clearance of lung fluid at birth, all helping to optimise neonatal lung function. These animal expriments are supported by clinical studies suggesting a reduction in the incidence of respiratory problems following treatment of the pregnant mother with corticosteroids and various Beta sympathomimetic drugs. Various factors, both physiological and pathological, considered to influence fetal lung maturity in the human are discussed in Chapter 3, with regard to both clinical and biochemical lung maturity. In addition, the available evidence linking the obstetric factors with the human fetal adrenocortical and sympathoadrenal responses is presented. A total of 381 babies were investigated in this study, of which 189 were born at or prior to 35 weeks' gestation. Lung maturity was assessed clinically by the occurrence of the respiratory distress syndrome and the requirement for neonatal ventilation and biochemically by measurement of amniotic fluid phospholipids. The fetal stress responses were assessed by measuring, in blood sampled from the umbilical artery at birth, the cortisol, noradrenaline and adrenaline levels and pH. These measurements were also made in maternal venous blood at time of delivery. (Abstract shortened by ProQuest.)
Analyzing implementation of the Natural Forest Protection Plan in China\u27s Southwestern Forest Management Region
Structure of the sugar phosphates by x-ray method
The structure of a-Glucose-1-Phosphate, the Cori Ester, in
the form of its dipotassium salt dihydrate has "been determined and
the structure compared with those of analogous compounds.
The methods used were hased mainly on the three-dimensional
vector function, partly using the isomorphous diammonium-Glucose1-Pho8phate dihydrate. The information derived from the short
intramolecular vectors appearing round the origin of the 'sharpened'
vector map was found to he particularly valuable. Direct methods
of sign determination were also examined and found to he potentially
useful.Refinement was carried out initially by Fourier methods and
finally by the method of Least Squares, all such calculations being
done on the D.E.U.C.E. Computer of Glasgow University.
The molecular structure is confirmed as being that found by
purely chemical methods. The Glucose-1-Phosphate molecule possesses
the long (1.59 °A) phosphorous-ester oxygen "bond which is found in
other sugar phosphate structures and which seems to he characteristic
of this class of compound. In addition, the bond from carbon (1)
to the ester oxygen is shorter (1.37 °A) than average. The angle at
this oxygen, 124°, is rather wide.The crystal structure itself is held together by a comprehensive
system of non-covalent bonds linking the cations, the free oxygens of
the phosphate group, the hydroxyl groups of the sugar ring, and the
water molecules. The completeness of this system explains the
comparative hardness of the crystal and its lack of any preferred
cleavage
“STRANGE SIMILES”: THE FAERIE OUEENE AND RENAISSANCE NATURAL HISTORY
Animals appear in every canto of every book of The Faerie Queene. This dissertation seeks to accentuate the strangeness of Spenser’s animals as well as to counter it. By placing Spenser’s epic in dialogue with early modem natural history, with which it shares a constant didacticism, I argue that the strangeness of his animals must first be recognized and then remedied by learning what was “meant” by those animals in the culture Spenser inhabited and helped make. Chapter One proposes ways in which Spenser, inhabiting a particular cultural time, place, and position, could have learned natural history as part of his formal education. Chapter Two argues for the centrality of exemplary symbolism in the presiding attitudes towards animals held during Spenser’s lifetime and how the practices and products of natural history embody these attitudes. Chapters Three and Four engage directly with two representative animals from Spenser’s poem, the lion and the crocodile, showing that animals are not merely imaginative conveniences but instead are complex, culturally encoded signifiers. The thesis also includes an appended compendium of all the animals of The Faerie Queene
Evaluating Productivity of Southern Agroforestry for Fiber, Biofuels, and Wildlife Habitat
Wildlife habitat values associated with agroforestry systems in Mississippi are not fully understood. Landscape matrix changes resulting in close location of various agricultural and tree crops can provide habitat more suitable for use by game wildlife. This study examined the feasibility of improving habitat value by adopting agroforestry alley cropping practices. A completely randomized block design was utilized to ascertain production values for two different even-aged crop trees, shortleaf pine (Pinus echinata Mill.) and loblolly pine (Pinus taeda L.), and four different agricultural crops, corn (Zea mays L.), switchgrass (Panicum virgatum L.), grain sorghum (Sorghum bicolor L.), and soybeans (Glycine max L.). Breeding bird surveys and camera surveys were used to quantify wildlife use and determine habitat improvement produced by this agroforestry management. If agroforestry land management improves wildlife habitat quality so hunters are willing to pay higher premiums, landowners can generate additional economic return from hunting leases
Open and Closed Mindedness, Values, and Other Personality Characteristics of Male College Students Who Served On or Appeared Before Judiciary Boards
Problem: The purpose of this study was to determine the direction of change in selected attitudinal characteristics of male students who were either members of a judiciary board (Group 1, N=51), or appeared before a judiciary board (Group 2, N=ll), or had no contact with a judiciary board (Group 3, N=110) while living in the residence halls at the University of North Dakota.
Procedure: The main sources of data for this study were the Allport- Vernon-Lindzey Study of Values, the Rokeach Dogmatism Scale E, and the Adjective Check List. These instruments were administered to the research population early in the first semester and late in the second semester of the 1968-69 academic year. Specially constructed questionnaires for the student groups and the head residents provided additional data.
The statistical techniques employed in this study included analysis of variance, analysis of covariance, and Dunn\u27s c test. The .05 level was employed as the critical level for determining the significance of the obtained differences.
Findings: 1. There was a significant difference among the three groups between initial testing and retesting for the open and closed mindedness variable, with Group 2 scoring higher (becoming more closed minded) than Group 1 and Group 3.
2. There was a significant difference among the three groups between initial testing and retesting for the number of unfavorable adjectives checked variable. A significant difference was found between Group 1 and Group 3, with the former scoring higher.
3. There was a significant difference found on the variable, self-control, among the retest means for the three groups. A significant difference was found between Group 2 and Group 3, with the latter scoring higher.
4. There was a significant difference found on the variable, heterosexuality, among the retest means for the three groups, with Group 2 scoring higher than Group 1 and Group 3.
5. There was a significant difference among the three groups between initial testing and retesting for the heterosexuality variable. A significant difference was found between Group 2 and Group 3, with the former scoring higher.
6. There was a significant difference found on the variable, exhibition, among the retest means for the three groups. A significant difference was found between Group 2 and Group 3, with the former scoring higher.
7. There was a significant difference found on the variable, change, among the retest means for the three groups. A significant difference was found between Group 2 and Group 3, with the former scoring higher.
8. There was a significant difference found on the variable, deference, among the retest means for the three groups, with Group 1 and Group 3 scoring higher than Group 2.
9-. There was a significant difference found on the variable, counseling readiness, among the retest means for the three groups. A significant difference was found between Group 2 and Group 3, with the latter scoring higher.
Conclusions: 1. There were no significant differences or changes in the values of students who served on a judiciary board, appeared before a judiciary board, or had no contact with a judiciary board.
2. Students who appeared before a judiciary board became more closed minded, more authoritarian, and less receptive to new ideas.
3. Students who appeared before a judiciary board lacked self-control, were outgoing, self-centered and narcissistic. In addition, they were opportunistic and manipulative, placed high priority on change and disorder, and were authoritarian, as well as ambitious.
4. Judiciary board members were increasingly perceived by their peers as being cynical, rebellious, and punitive
An investigation of fuel cell electrode activity influenced by alternating current electric fields
Two methods of applying an alternating current electric field to the grid electrodes of the fuel cell systems were studied. Both methods were used to enhance the power output of the system. The alternating current electric field was applied to the grid electrodes to induce greater ionic motion, reduce the concentration polarization losses due to the ionic film double layer, and to desorb catalyst poisons and strongly adsorbed ions from the fuel cell electrode surfaces. The enhancement of the fuel cell system power was found to be a function of the applied voltage and frequency. A greater, applied alternating field voltage resulted in an increased power enhancement. In the first method, a maximum enhancement of 42,000 percent, at an applied voltage of 0.3 volt, was asymptotically approached as the frequency of the alternating current field was increased from 0.5 to 1000 cycles per second. This maximum enhancement corresponded to an output power of 3,000 microwatts. The input power from the alternating field was determined to be no greater than .3,000 microwatts. Also, a retention of the power enhancement for a short period after the removal of the applied alternating field was noticed and measured. In the second method, a maximum enhancement of 670 percent was obtained at an applied voltage of 0.3 volt and a frequency of three cycles per second. A power input of 9,000 microwatts was needed to obtain the 670 percent enhancement. This" power input was much greater than the enhanced power output obtained from the fuel cell system. Grid electrodes were positioned in the gas phase behind the fuel cell electrodes and initial studies indicated that such a con figuration consumed negligible input power while still producing an enhanced fuel cell power output. When the effects of the semiconductive materials were investi gated, a wafer of n-type silicon was used as the hydrogen electrode and a p-type silicon wafer was used as the oxygen electrode. The open circuit voltage of this configuration was 7.0 millivolts. An open circuit voltage of 4.5 millivolts was measured when the hydrogen electrode was p-type silicon and the oxygen electrode was n-type silicon. The difference between the two configurations indicated that, by assembling the fuel cell system in the same manner as the first configuration considered, an increase in open circuit voltage may be achieved
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