1941 research outputs found
Sort by
The Efects of Dose and Time of Administration of Pentylenetetrazol on a Visual Discrimination Task
Get PDF42 leaves.The problem: The purpose of this study was to determine if a given range of pentylenetetrazol doses differentially affected retention of a visual discrimination task in the rat as a function of time of administration after training was completed.
Procedure: Using food reinforcement, 36 rats were trained to perform a brightness discrimination in a Y-maze until they reached a criterion of nine out of ten correct responses. They were then injected with either 10.0, 12.5 or 15.0 mg/kg pentylenetetrazol at intervals of either 0,5 or 15 minutes after completion of training. Twenty-four hours later a test of retention was given. This consisted of counting the number of errors made by each rat in 15 additional trials run under identical conditions in the Y-maze as on the previous day. Using the number of errors made by each rat as the dependent variable, the data was analyzed by a two-factor completely randomized analysis of variance.
Findings: The results of this study indicated that the number of errors wsde by the rats was dependent upon the dosage of drug and the time intervals after training at which it was administered. Overall, pentylenetetrazol was shown to facilitate retention of the brightness discrimination task. In addition, it was found that the effectiveness of the drug in facilitating retention decreased linearly with increasing delay of injection.
Conclusion: It was concluded that although pentylenetetrazol in the range of doses investigated facilitates retention for a learned task, there exists a critical period after training has been completed after which injections of the drug lose their utility in facilitating retention. Within this critical period, there is a linear decrement in the drug's effectiveness with increasing delay of injection after completion of training.
Recommendations: It is recommended that procedural guidelines and a system for the standardization of variables be formulated and adhered to when conducting experiments of this sort. This would most likely serve to eliminate various discrepancies, both major and minor, now found in the results of these experiments
Benthic Population Distributions in Red Rock Reservoir, Iowa Summer 1972
Get PDF46 leaves.The problem. To determine the distribution of benthic invertebrates in Red Rock Reservoir and to relate this distribution to the physiochemical characteristics of the substrate and bottom meter of water along with water retention time after three years of impoundment.
Procedure. Benthic samples were obtained at weekly intervals with a Ponar dredge from two transects of six stations each from June 9 to August 1, 1972. Bottom sediments were analyzed for organic content, pH and particle size. Bottom waters were analyzed for dissolved oxygen content, alkalinity and free carbon dioxide. Depth and temperature readings were recorded at each station.
Findings. During the study three major groups comprised the benthos. Of the total numbers collected during the study Oligochaeta comprised 52.4%, Chironomidae 44.8% and Chaoborus 2.8%. Total mean numbers collected ranged from 24 to 212 organisms/m2. Thermal and chemical stratification of the bottom waters occurred temporarily.
Conclusions. The benthic standing crop in Red Rock Reservoir has increased since 1970 but the amount of biomass present and the mean density of organisms was below values obtained from other reservoirs. Low numbers of Chaoborus present were due to emergence patterns. Factors which appeared to influence benthic population distributions include substrate organic content and particle size, low water retention time and presence of the old river channel.
Recommendations. Future studies should determine the exact species composition of the benthos and how life cycle patterns are related to benthic biomass production and distribution. The influence of fish predation and sedimentation and the loss of production via reservoir flowthrough should be investigated
Variations of Physical and Chemical Parameters Within a Shallow Wind Influenced Lake
No full text28 leaves.The problem. It was felt that a comprehensive analysis of the seasonal variations of physical and chemical parameters of a small Iowa artificial lake was needed. Such a study would establish a reference point for future developments in terms of water quality and useage of the defined area.
Procedure. Lake Easter, Polk County, Iowa, was studied from April 18 to July 2, 1969. Samples of the water were taken from three sites and from the top and bottom water. Samples were tested for temperature, light penetration, turbidity, specific conductance, oxygen, alkalinity, hardness, nitrate, nitrite, ortho-phosphate, and pH. Chemical tests were performed with a Hach DrEL (Engineers Portable Water Testing Laboratory).
Findings. The lake was found to have no pronounced thermal stratification. Light penetration was good, turbidity was near 0 mg/l, and specific conductance was similar to other hard alkaline lakes in the area. No sustained chemical stratification occurred although during periods of warm, calm air occasional low reading of dissolved oxygen were recorded. High levels of nitrate, nitrite, and ortho-phosphate were recorded.
Conclusions. The lake was found to have only temporary thermal and chemical stratification. Variations of physical and chemical parameters were found to be related to wind and rainfall. The lake is suspected to be receiving pollutants from some source and is in danger of rapid eutrophication due to the high level of plant nutrients, clear water, and large euphotic zone.
Recommendations. A year long study of physical and chemical parameters would be useful as would a study of the productivity in view of the high nutrient levels and large euphotic zone. The source of pollutants should be studied. A survey of aquatic plant and animal species is also recommended
Liability Without Fault : An Analysis of the Scope of Workmen's Compensation With Specific Emphasis on its Development in Iowa
Get PDF172 leaves.Several million persons become the victims of industrial accidents annually. The suffering of an occupational injury by a wage earner is a severe blow. His income may be temporarily or permanently interrupted while at the same time his expenses increase because of the need for medical care. In the event of a permanent disability, his future earning power may be decreased. Workmen's compensation laws are designed to indemnify injured workers and their families. Their objective is the payment of medical costs, the continuance of the worker's income during the entire period of his disability, the compensation of a permanently disabled worker for any future reductions in earning power and the payment of benefits to the dependents of a fatally injured worker.
This study examines the scope and development of workmen's compensation and the extent to which Iowa's law meets the goals of providing sure, prompt and reasonable income and medical benefits to work-accident victims, or income benefits to their dependents, regardless of fault. The current benefit provisions of Iowa's Workmen's Compensation Law in relation to selected states and to wage and income data are examined in order to evaluate their adequacy in terms of the benefits that currently accrue to a worker. Survey data is used to determine an approximation of the weekly disability payment in Iowa due to the general lack of statistics in the area of workmen's compensation paid.
Iowa was among the first states to recognize the plight of the injured worker and to enact a workmen's compensation statute. The benefits provided include periodic cash payments, lump-sum payments, medical care to the worker during the period of disability and death benefits to the worker's survivors. However, the stated intent of Iowa's Workmen's Compensation Law to replace two-thirds of a worker's weekly wage during total disability is defeated by the existence of weekly maximum dollar limits on benefits. Iowa's workmen's compensation benefits also fall short of the poverty income guidelines established by the Social Security Administration. Employees who suffer a disabling injury of long duration and the dependents of fatally injured workers are most affected. Unless persons in this group have some supplementary income, the workmen's compensation benefits they receive are not sufficient to keep them above the level of poverty
Negative Capability in the Characters of Keats' Magor Poetry
Get PDF80 leaves.The intention of this thesis is to prove that "negative capability" exists within the characters of Keats' major poetry. But a problem arises in defining "negative capability." In the introductory chapter the term is redefined as a speculation on a style and ideal of life, as opposed to a style of art, and the contention is made that Keats found a voice for his speculations on "negative capability" in the characters of his major poems.
The following poems are discussed: "Ode to a Nightingale, Hyperion, and Lamia. The discussions focus primarily on these three points: (1) the degree to which each character possesses "negative capability" (i.e., his ability for self-negation, empathic-identification, and disinterestedness); (2) the progression of the protagonist towards "negative capability" and his reactions upon achieving that ideal; and (3) the consequences suffered by those who fail to function with "negative capability." The "Ode to a Nightingale" and Hyperion deal primarily with the ideal aspect of "negative capability"; Lamia and, to some extent, Hyperion deal with the concept as a style of life.
The discussions attempt not only to prove that "negative capability" does exist within the characters of Keats' major poetry, but also to demonstrate the validity of the definition of "negative capability" as a speculation on a style and ideal of life, and thus to discover another dimension of Keats' elusive term
The Effect of Leucogenenol on Classical Chemotherapy and Immunotherapy of Friend Virus Disease
Get PDF50 leaves.The problem. These experiments determined the effects of the immunostiumulants leucogenenol and Bacille Calmette-Guerin (BCG) in combination with Methotrexate chemotherapy on Friend Virus Disease. Procedure. FV infected mice were treated with various combinations of the chemo-and immunotherapeutic agents being investigated. Three parameters of the disease, survival time, ratios of spleen and liver weight to total body weight and periodic differential counts of peripheral blood were studied and analyzed. Findings. Although Methotrexate significantly prolonged survival time in animals thus treated, the other parameters examined were not significantly different from the untreated controls at the time of death. Immunostimulation with leucogenenol, BCG, or both had no appreciable effect on any of the parameters of the disease. Conclusion. It was concluded that the effect of MTX therapy was to suppress the production and sensitization of T-lymphocytes so efficiently that consequent attempts at restimatulation were ineffective. Furthermore, this suppression was sufficiently great so that upon cessation of MTX therapy the proliferation of leukemia cells probably exceeded that of new, immunocompetent T-lymphocytes. Recommendations. More studies on the molecular and cellular action of leucogenenol are necessary. An important question raised by this study is which kind of lymphocytes are stimulated by leucogenenol. If only B-lymphocytes are affected, the overall result may be to enhance tumor growth by a blocking effect on the tumor receptor sites. Further, leucogenenol should be tried as therapy against a solid, localized tumore system which does not directly affect the hemotopoietic process
Relationships Between Poe's Imagery and His View of the Universe
Get PDF55 leaves.Poe's images in both his prose and his poetry are closely related to his concept of the universe and man's position in it. The images suggest many of the ideas Poe presents in Eureka. Much of the preparation for this thesis was involved with a careful reading of Poe's work. His critical writing, especially Eureka, was studied in an attempt to make some basic observations about his philosophy. His prose and poetry were then viewed in light of his basic philosophical assumptions. Conclusions were then drawn regarding the appropriateness of Poe's images for his central themes. Secondary sources were consulted either to expand or substantiate some of the arguments of the thesis. Poe describes the universe in terms of repulsion and attraction, forces that work on both the physical and the spiritual dimensions. Repulsion has caused a moving away from unity; consequently, Poe's images reflect the superiority of the past and the inferiority of man's present condition. However, the attractive force sends all in the direction of unity and, therefore, is associated with positive images. In addition, Poe's images suggest man's quest for spiritual understanding and his attempt to reconcile the demands of his body with the demands of his soul
The Observable Effects of Acetylcholine, Succinylcholine, D-tubocurarine and Quinine and Their Binary Combinations on Tardigrades
Get PDF30, [1] leaves.The problem. This study seeks to determine the observable effects of acetylcholine, succinylcholine, d-tubocurarine, and quinine on tardigrades and to compare these effects to known mammalian reactions. Evidence of synergism or antagonism is sought by combining each drug compound with the other three individually. Procedure. Three species of tardigrades (Milnesium tardigradum, Hypsibius oberhauseri, and Macrobiotus richtersi) were subjected to serial dilutions and 4.0% to 0.0% (weight/volume) of each of the four compounds and their binary combinations. Observations were made through a 25x binocular dissecting microscope at the time periods: 15 minutes, 1 hour, and 5 hours. Controls were kept in distilled water and in spring water. All test animals were kept in a moist-chamber to avoid evaporation and subsequent concentration of the test solutions. Anesthesia was tested by returning affected anmials to spring water and watching for movement, indicating recovery. Findings. Contraction of the tardigrades' bodies and legs was brought about within an hour by a minimum of 0.4% acetylcholine or 1.6% succinylcholine. In that same time period the tardigrades were relaxed, with the bodies and legs fully extended, by 1.2% d-tubocurarine; but no change was seen with up to 2.0% quinine. By 5 hours, 0.8% quinine had caused a relaxation of the animals. Acetylcholine and succinylcholine were highly synergistic. Both quinine and d-tubocurarine sensitized the tardigrades to acetylcholine. D-tubocurarine delayed the action of succinylcholine. Small amounts of d-tubocurarine negated effects of 2.0% or less succinylcholine, causing no observable effects. Quinine casued a delayed sensitization of the tardigrades to succinylcholine. D-tubocurarine and quinine delayed and reduced the effectiveness of each other. The effect of these test solutions was anesthesia, not narcosis. This was demonstrated by the recovery of the affected tardigrades when they were returned to spring water
Maintenance of Swimming Pools in the Secondary Schools of Iowa
Get PDFvi, 81 leaves. Advisor: Neal TrembleThe problem. It was the purpose of this study to
determine whether or not the Secondary Schools of Iowa were maintaining hygienically safe swimming pools.
Procedure. After reviewing current professional
literature, a questionnaire was prepared. The questionnaire was made up of items involved in adequate maintenance of swimming pools. The questionnaire was validated by maintenance
personnel in nine of the colleges and universities
of Iowa. Arter the suggestions and recommendations of the validating institutions were compiled, a revised questionnaire and letter of transmittal were sent to the forty-five secondary schools with swimming pools. Forty of the questionnaires were completed and returned.
Findings. A wide range of swimming pool maintenance procedures, ranging from pools that are very well maintained to those that illustrate careless maintenance, was observed. At the present time the majority of the swimming pools in the forty reporting schools are adequately maintained. However, the following areas deserve attention: (1) Over one half of the maintenance personnel have not had any chemistry background; (2) There is no definite method of training maintenance
personnel; and (3) The majority of the maintenance
personnel do not have a true understanding of the filter system
Species Diversity of Benthic Macroinvertebrates in the Des Moines River, Iowa
Get PDF31 leaves.Problem. Evaluation of the water quality of the Des Moines River. Iowa by sampling and analyzing the benthic macroinvertebrate community.
Procedure. Artificial substrates at four stations were used to collect benthic macroinvertebrates. Community structure was analyzed with species divorsity indices. Species diversity (D) and redundancy (R) values were used to calculate standardlzed distance (SD) values. The indices were analyzed statistically.
Findings. The average D values ranged from 1.62 to 1.94. Mean standardized distance (SD) values were lowest immediately above the metropolitan Des Moines area and highest immediately downstream from the metropolitan Des Moines
area.
Conclusion. According to species diversity (D) values, the entire Des Moines River in the study area exhibited mild pollution. Differences in: community structure do exist in the river. Differences in standardized distance (SD) values are attributed to influences that the metropolitan area had on the river. Red Rook Reservoir showed no statistically significant effects on the station immediately downstream.
Recommendations. Recommendations for further study are: (1) Follow-up species diversity and productivity studies after Saylorville Reservoir is impounded. (2) Follow-up study with more sample sites between stations 2 and 3 incorporating chemical analysis of water to pinpoint the site of most drastic water quality change