Showing papers by "Michigan State University published in 1977"
TL;DR: Nine of the enzyme activities were eliminated with cyanide treatment suggesting that they may be cupro-zinc enzymes, whereas one was cyanide-resistant and may be a manganese enzyme.
Abstract: Shoots, roots, and seeds of corn (Zea mays L., cv. Michigan 500), oats (Avena sativa L., cv. Au Sable), and peas (Pisum sativum L., cv. Wando) were analyzed for their superoxide dismutase content using a photochemical assay system consisting of methionine, riboflavin, and p-nitro blue tetrazolium. The enzyme is present in the shoots, roots, and seeds of the three species. On a dry weight basis, shoots contain more enzyme than roots. In seeds, the enzyme is present in both the embryo and the storage tissue. Electrophoresis indicated a total of 10 distinct forms of the enzyme. Corn contained seven of these forms and oats three. Peas contained one of the corn and two of the oat enzymes. Nine of the enzyme activities were eliminated with cyanide treatment suggesting that they may be cupro-zinc enzymes, whereas one was cyanide-resistant and may be a manganese enzyme. Some of the leaf superoxide dismutases were found primarily in mitochondria or chloroplasts. Peroxidases at high concentrations interfere with the assay. In test tube assays of crude extracts from seedlings, the interference was negligible. On gels, however, peroxidases may account for two of the 10 superoxide dismutase forms.
4,882 citations
827 citations
TL;DR: In this article, an effective local interaction for inelastic scattering is derived by fitting the matrix elements of a sum of Yukawas and, for the tensor force, other closely related forms, to three selected sets of G-matrix elements.
790 citations
TL;DR: It is suggested that endogenous morphinomimetic substances may participate in regulating secretion of anterior pituitary hormones through regulating the response to naloxone and morphine.
580 citations
TL;DR: The superoxide dismutase activity per plant and per milligram water-soluble protein considerably increased during germination of oats and during greening and hook opening of peas.
Abstract: Superoxide dismutase was purified from pea (Pisum sativum L., cv. Wando) seeds and corn (Zea mays L., cv. Michigan 500) seedlings. The purified pea enzyme eluting as a single peak from gel exclusion chromatography columns contained the three electrophoretically distinct bands of superoxide dismutase characterizing the crude extract. The purified corn enzyme eluted as the same peak as the pea enzyme, and contained five of the seven active bands found in the crude extract. The similar molecular weights and the cyanide sensitivities of these bands indicated that they are probably isozymes of a cupro-zinc superoxide dismutase. One of the remaining corn bands was shown to be a peroxidase.Superoxide dismutase accounted for 1.6 to 2.4% of the water-soluble protein in seedlings of corn, peas, and oats (Avena sativa L., cv. Au Sable). The superoxide dismutase activity per plant and per milligram water-soluble protein considerably increased during germination of oats and during greening and hook opening of peas.
527 citations
TL;DR: Standard experimental procedures for continuous polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate were modified to give more effective separation and improved resolution of myofibrillar proteins.
518 citations
TL;DR: This article reviewed the literature on job involvement and identified various definitions of the term and integrated them into three theoretical perspectives: job involvement as an individual characteristic, as a situationally determined variable, and as a product of person.
Abstract: Reviews the literature on job involvement. First, the various definitions of the term are identified and integrated. Next, 3 theoretical perspectives on job involvement are considered: job involvement as an individual characteristic, as a situationally determined variable, and as a product of person
503 citations
TL;DR: During the cleavage of glycosidic linkages by anhydrous hydrogen fluoride there is little or no degradation of the sugars themselves, thus allowing their quantitative recovery, which may also be useful in the analysis of complex polysaccharides.
352 citations
TL;DR: Denitrification appears to be a property of a very diverse group of gram-negative, motile bacteria, as shown by the large number (22.6%) of ungrouped organisms.
Abstract: Nineteen soils, three freshwater lake sediments, and oxidized poultry manure were examined to determine the dominant denitrifier populations. The samples, most shown or expected to support active denitrification, were from eight countries and included rice paddy, temperate agricultural, rain forest, organic, and waste-treated soils. Over 1,500 organisms that could grow anaerobically on nitrate agar were isolated. After purification, 146 denitrifiers were obtained, as verified by production of N2 from NO3-. These isolates were characterized by 52 properties appropriate for the Pseudomonas-Alcaligenes group. Numerical taxonomic procedures were used to group the isolates and compare them with nine known denitrifier species. The major group isolated was representative of Pseudonomas fluorescens biotype II. The second most prevalent group was representative of Alcaligenes. Other Pseudomonas species as well as members of the genus Flavobacterium, the latter previously not known to denitrify, also were identified. One-third of the isolates could not utilize glucose or other carbohydrates as sole carbon sources. Significantly, none of the numerically dominant denitrifiers we isolated resembled the most studied species: Pseudomonas denitrificans, Pseudomonas perfectomarinus, and Paracoccus denitrificans. Denitrification appears to be a property of a very diverse group of gram-negative, motile bacteria, as shown by the large number (22.6%) of ungrouped organisms. The diversity of denitrifiers from a given sample was usually high, with at least two groups present. Denitrifiers, nitrite accumulators, and organisms capable of anaerobic growth were present in the ratio of 0.20±0.23:0.81±0.23:1. There were few correlations between their numbers and the sample characteristics measured. However, the temperatures at which isolates could grow were significantly related to the temperatures of the environments from which they were isolated. Regression analysis revealed few relationships between physical parameters and bacterial types, save for the anaerobe numbers, in which 94% of the variance could be accounted for.
344 citations
TL;DR: Although many of the C-3 substituted indoles such as indole-3-acetic acid and tryptamine had colors in the reddish-violet-blue color region, most exhibited sufficient color differentiation to allow their identification by thin-layer chromatography.
341 citations
TL;DR: In this article, the authors discuss the role of lipids in meat flavor, both the desirable and undesirable, and discuss the mechanisms of lipid oxidation, including autoxidation, catalysts of lipid oxidations, and comparison of heme and nonheme iron as pro-ox didants in muscle tissue.
Abstract: Publisher Summary This chapter discusses “warmed–over” flavor (WOF) in meat, poultry, and fish. In the first section, the classification and significance of lipids is described. It explains the structure of lipids and the composition of animal fats. The role of lipids in meat flavor, both the desirable and undesirable, are presented. Next section discusses the mechanisms of lipid oxidation. It delves into the topics of autoxidation, catalysts of lipid oxidation, comparison of heme and nonheme iron as pro–oxdidants in muscle tissue, and phospholipid oxidations. In the subsequent section, development of WOF, the species differences in WOF, influence of deboned meat, influence of heating, influence of chopping and emulsifying and effects of curing are explained. A discussion on the prevention of WOF in meat, poultry, and fish is also presented in the last section.
TL;DR: Results of the studies indicate that the Myers-Briggs Type Indicator is an adequately reliable self-report inventory, measuring dimensions of personality which seem to be quite similar to those postulated by Carl Jung.
Abstract: A comprehensive assessment of the Myers-Briggs Type indicator is presented, including a description of the four personality scales measured by the instrument, a summary of the scoring process, and an extensive review of intercorrelation studies, reliability studies, and validity studies conducted with the Indicator. Results of the studies indicate that the Myers-Briggs Type Indicator is an adequately reliable self-report inventory. The Extraversion-Introversion Sensation-Intuition, and Thinking-Feeling scales appear to be relatively independent of each other, measuring dimensions of personality which seem to be quite similar to those postulated by Carl Jung.
TL;DR: A method of scaling is proposed to estimate the positions of candidates and voters on a common issue dimension and the resulting ideal point estimates are related to candidate positions in 1968 to test a simple Downsian voting model.
Abstract: A method of scaling is proposed to estimate the positions of candidates and voters on a common issue dimension. The scaling model assumes that candidates occupy true positions in an issue space and that individual level perceptual data arise from this in a two step process. The first step consists of a stochastic component, satisfying the standard Gauss Markov assumptions, which reflects true misperception. The second step consists of a linear distortion which is introduced in the survey situation. Estimates of the parameters of the model are developed by applying the least squares criterion, and distributions of the estimates are investigated by Monte Carlo methods.The scaling technique is applied to the seven-point issue scales asked in the 1968 and 1972 SRC survey. The resulting ideal point estimates are related to candidate positions in 1968 to test a simple Downsian voting model.
TL;DR: The data suggest that a decrease in catecholamine and an increase in serotonin metabolism occur in the hypothalamus of old male rats, which may be related to the decrease in release of gonadotropins and increase inrelease of prolactin observed in these old male Rats.
Abstract: The steady state concentration of dopamine (DA), norepinephrine (NE), and serotonin (5HT) was determined and turnover estimated in several brain regions of young (3–4 months) and old (21 months) male Wistar rats. An estimate of DA and NE turnover was obtained by determining their depletion rates after treatment with α-methylpara- tyrosine, a tyrosine hydroxylase inhibitor. Serotonin turnover was estimated by determining its rate of increase after monoamine oxidase inhibition with pargyline. In old males, medial basal hypothalamic (MBH) DA concentration and depletion rate were significantly lower than in young males. DA concentration of the remaining hypothalamus also was lower in old than in young males, but depletion rates were not different. DA concentration and depletion rate in the olfactory tubercle were the same in both age groups. The steady state concentration of NE in the MBH and remaining hypothalamus, and the hypothalamic NE depletion rate, were significantly lower in old than in young animals....
TL;DR: All plant tissues examined contained most of their IAA as derivatives, either esterified or as a peptide; the cereal grains examined contained mainly ester IAA; and the legume seeds examined contain mainly peptidyl IAA.
Abstract: Seeds of oat, coconut, soybean, sunflower, rice, millet, kidney bean, buckwheat, wheat, and corn and vegetative tissue of oat, pea, and corn were assayed for free indole-3-acetic acid (IAA), esterified IAA, and peptidyl IAA. Three conclusions were drawn: (a) all plant tissues examined contained most of their IAA as derivatives, either esterified or as a peptide; (b) the cereal grains examined contained mainly ester IAA; (c) the legume seeds examined contained mainly peptidyl IAA. Errors in analysis of free and bound IAA are discussed.
TL;DR: In this paper, the authors investigate the possible control strategies a persuader may use and to determine how situational differences affect a persuaders' strategic choices, and conclude that a general typology of control strategies is improbable.
Abstract: The purpose of this study was to investigate the possible control strategies a persuader may use and to determine how situational differences affect a persuader's strategic choices. By modifying an earlier study of Marwell and Schmitt, dimensions of control strategies were sought in four situations: interpersonal, long‐term consequences; interpersonal, short‐term consequences; nonin‐terpersonal, long‐term consequences; and noninterpersonal, short‐term consequences. Respondents were obtained from students at a Midwestern state university and a community college, and from army recruiters enrolled in a college extension course. Results indicated that situational differences affected the cluster structures and led to the conclusion that a general typology of control strategies is improbable.
TL;DR: Application of the binding of Coomassie brilliant blue G-250 to protein in an acid-denaturing solvent shows that the method is a rapid and reproducible method, but that it is of limited analytical value since it shows a wide variability in its sensitivity to various proteins.
TL;DR: A relatively new approach to the study of teaching assumes that what teachers do is affected by what they think as discussed by the authors, and this cognitive information processing approach is concerned with teacher judgment, decision making, and planning.
Abstract: A relatively new approach to the study of teaching assumes that what teachers do is affected by what they think. This cognitive information processing approach is concerned with teacher judgment, decision making, and planning. The study of the thinking processes of teachers-how teachers gather, organize, interpret, and evaluate information-is expected to lead to understandings of the uniquely human processess that guide and determine teacher behavior. This view of teaching developed as a logical outgrowth of approaches to research on teaching that emphasize teacher behavior. The teacherbehavior approach has contributed a great deal to our knowledge of what teachers and students do in classrooms and how this behavior relates to student learning and attitudes (see Rosenshine 1971; Dunkin and Biddle 1974; Medley, in press). But if the results of such research are to be applied by individual teachers in their classrooms, adaptations will have to be made. Each class consists of a unique combination of personalities, constraints, and opportunities. Teacher behavior that is sensible and effective in one setting may be inappropriate in a second setting, and it is the individual teacher who makes decisions about appropriateness and defines the teaching situation. So, if research is to be put into practice-if the general case is to be applied in particular situations-then we must know
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TL;DR: Fungistasis with characteristics similar to that in soil may also occur on leaves of plants, and is annulled by energy‐yielding nutrients.
Abstract: SUMMARY
1. Fungistasis in soil is a widespread phenomenon affecting most fungal propagules, though some are insensitive. In most instances, it is coexistent with the presence of living microorganisms, and is annulled by energy-yielding nutrients. Fungistasis with characteristics similar to that in soil may also occur on leaves of plants.
2. Germination and growth of bacteria and actinomycetes is also restricted in soils. The characteristics of their inhibition appear to be the same as those for fungi. Therefore, the concept of a widespread microbial inhibition in soil can be applied to all three groups of microorganisms.
3. Fungistasis can be detected by various direct methods, or indirectly by methods involving the use of porous or permeable carriers. It may be expressed as a restriction on the final amount of germination (the usual parameter), germination rate (with time), and rate of germ-tube or hyphal growth. Since the expression of fungistasis is often complete in soil, titration with nutrients may be required to distinguish between the sensitivities of different fungi.
4. Fungistasis generally is expressed most strongly at soil moisture contents somewhat less than saturation. Its expression usually is maximal in neutral or slightly alkaline soils. In acidic conditions fungistasis may be lessened because of suppression of bacterial and actinomycete activity. Increased sensitivity of some fungi in soils of pH > 7.0 may be caused by a directly unfavourable effect of pH on the fungus.
5. Fungal species with small spores tend to be highly sensitive to fungistasis. These spores tend to germinate slowly and to require exogenous nutrients for germination. By contrast, species with larger spores and sclerotia often do not require exogenous nutrients for germination. The larger spores tend to germinate rapidly and to exhibit low sensitivity, as compared with small spores. A few nutrient-independent spores are insensitive to fungistasis. At least a part of the difference in sensitivity is related to germination time; spores which germinate slowly compete poorly with the soil micro-flora for their nutrients.
6. Fungistasis is often temporarily annulled by enriching the soil with energy-yielding nutrients. Usually, complex materials such as plant residues are most effective. A few weeks after such treatment, the level of fungistasis may, however, be increased. Annulment of fungistasis by compounds not utilized as energy sources has not yet been demonstrated.
7. Several soils naturally suppressive to Fusarium wilt diseases were more fungistatic to Fusarium than soils conducive to wilt. Potential means by which fungistasis may be manipulated to control root-infecting fungi are (a) through stimulation of germination with nutrients, thus exposing the germ tube to lysis, and (b) by increasing the fungistatic level of soil through appropriate amendments.
8. Volatile substances identified in soils, some of which are potentially inhibitory to fungi include (a) ammonia, which apparently is evolved from ammonium salts in some arid soils of high pH, (b) ethylene, which has been identified in some soils of pH < 7.0 (though high levels of this gas seem to be tolerated by most fungi), (c) allyl alcohol, and (d) other unidentified substances. Non-volatile inhibitors include high molecular weight substances revealed by molecular sieve chromatography of soil extracts. Microbial metabolites such as those present in staled fungal cultures also have been proposed to account for fungistasis. In a few soils fungistasis persists after sterilization because of the presence of inhibitory concentrations of calcium carbonate, iron or aluminium. Inherent in the proposition that inhibitory substances provide the primary mechanism of fungistasis is the concept of a highly complex phenomenon, involving various highly specific inhibitory and counteracting stimulatory substances, with the outcome for the fungus depending on the kinds and relative amounts of each present.
9. By the nutrient-deficiency hypothesis, the level of available nutrients in soil is insufficient to support germination of nutrient-dependent propagules, except in nutrient-rich microsites. Inhibition of nutrient-independent propagules is explained by loss of endogenous nutrients required for germination, through microbial nutrient competition. Evidence for this hypothesis is (a) the imposition of fungistasis on numerous nutrient-independent propagules during incubation on leaching model systems designed to simulate microbial nutrient competition in soil, (b) similar losses of endogenous nutrients occurring on soil and the leaching system, and (c) the fact that soils are chronically deficient in energy in relation to the microbial populations present, with the consequence that enforced inactivity is imposed upon most of the population at any given time for this reason alone, regardless of the presence or absence of fungistatic substances.
Journal series article no. 7747 from the Michigan Agricultural Experiment Station.
TL;DR: One of the simplest topological variations of the phase space of a one-parameter family of differential equations (vector fields, flows) is the creation of periodic orbits from equilibria as the parameter crosses a critical value as mentioned in this paper.
TL;DR: Serum levels in serum LH, FSH, TSH and prolactin in response to LHRH + TRH injection in acutely or chronically starved rats were equal to or greater than in the ad libitum fed controls, indicating that severe reductions in food intake result in decreased release of at least 5 anterior pituitary hormones.
Abstract: Adult male Sprague-Dawley rats averaging 300 g each were subjected to complete food removal for 7 days (acutely starved), 7 days complete food removal followed by 2 weeks of ¼ ad libitum food intake (chronically starved), 7 days complete food removal and 2 weeks of ¼ ad libitum intake followed by ad libitum feeding for 7 days (refed), or fed ad libitum throughout (controls). Serum LH, FSH, TSH, PRL, and GH levels were measured by radioimmunoassays for each group of rats. The in vivo response to the combination of synthetic LHRH and TRH also was tested in each group. Circulating LH, TSH, GH, and PRL were significantly depressed in acutely and chronically starved rats, and FSH was lowered only in acutely starved rats. After 7 days of refeeding, serum levels of LH and FSH were significantly greater than in ad libitum fed controls, PRL returned to control levels, and TSH and GH increased but were still below control levels. After LHRH + TRH injection serum LH and TSH were increased significantly in all groups...
TL;DR: PCB toxicity experiments revealed that mink are very sensitive to these compounds and that the lethal dose varied inversely with the chlorine content of the PCB's although only Aroclor 1254 exerted a detrimental effect on reproduction when fed at a low level (2 ppm) for 8 months.
Abstract: Experiments were conducted from 1968 to 1974 to investigate reproductive complications and mortality in mink fed Great Lakes coho salmon and to ascertain the effects of polychlorinated biphenyls (PCB's) on this fur bearer The results of mink feeding trials indicated that coho salmon, as such, were not responsible for the loss of reproduction in the adult, or the kit mortality Mink diets that contained other species of Great Lakes fish caused similar reproductive complications, but to a lesser degree Rancidity, mercury poisoning and chlorinated hydrocarbon pesticide contamination of the fish were all discounted as being responsible for the problem The clinical signs and lesions noted in mink that died while receiving diets that contained Lake Michigan coho salmon were very similar to those observed in mink fed on rations that contained supplemental PCB's These included anorexia, bloody stools, fatty liver, kidney degeneration, and hemorrhagic gastric ulcers Analyses of tissues from mink that died when fed 30% Lake Michigan coho salmon or 30 ppm supplemental PCB diets showed similar PCB residues PCB toxicity experiments revealed that mink are very sensitive to these compounds and that the lethal dose varied inversely with the chlorine content of the PCB's although only Aroclor 1254 exerted a detrimental effect on reproduction when fed at a low level (2 ppm) for 8 months The reproductive failure encountered in feeding mink Lake Michigan coho salmon and Aroclor 1254 was shown to be of a non-permanent nature
TL;DR: Findings indicate that detectable morphological changes take place in the course of alterations in hydration state that are well within the physiological range.
Abstract: A quantitative ultrastructural study was performed to determine the changes in the neurosecretory neurons of the supraoptic (SON) and circularis (NC) nuclei following 4–24 h of water deprivation (WD) and subsequent rehydration (12 and 24 h). In both nuclei, the amount of direct soma-somatic contact increased throughout WD, apparently by retraction of fine glial processes from between the cells. Rehydration reversed these changes. The number of smaller (<1600 A) neurosecretory granules (NSG's) decreased in both nuclei at 4 h of WD but returned to control levels by 24 h of WD and remained so during rehydration. Larger (<1600 A) NSG's decreased in number at 4 h of WD in SON and then returned to control levels by 24 h of WD and remained the same throughout rehydration. In NC, these NSG's did not change in number with WD, but significantly increased between 12 and 24 h of rehydration. No cells with dilated rough endoplasmic reticulum were seen in NC during this study. In SON, however, the percentage of such cells increased at 4 and 12 h of dehydration only to decrease to control levels at 24 h of dehydration and throughout rehydration. Lysosomes decreased at 4 h of dehydration in SON and returned to control levels thereafter. In NC, lysosomes tended to decrease with dehydration and increase with rehydration. These findings indicate that detectable morphological changes take place in the course of alterations in hydration state that are well within the physiological range.
TL;DR: In this paper, a method for the isolation of metabolically active heterocysts from Anabaena cylindrica was described, which accounted for up to 34% of the acetylene-reducing activity of whole filament and had a specific activity of up to 1,560 nmol of C2H4 formed per mg of heterocyst chlorphyll per min.
Abstract: A method is described for the isolation of metabolically active heterocysts from Anabaena cylindrica. These isolated heterocysts accounted for up to 34% of the acetylene-reducing activity of whole filaments and had a specific activity of up to 1,560 nmol of C2H4 formed per mg of heterocyst chlorphyll per min. Activity of glutamine synthetase was coupled to activity of nitrogenase in isolated heterocysts as shown by acetylene-inhibitable formation of [13N]NH3 and of amidelabeled [13N]glutamine form [13N]N2. A method is also described for the production of 6-mCi amounts of [13N]NH3. Isolated heterocysts formed [13N]glutamine from [13N]NH3 and glutamate, and [14C]glutamine from NH3 and [14C]glutamate, in the presence of magnesium adenosine 5'-triphosphate. Methionine sulfoximine strongly inhibited these syntheses. Glutamate synthase is, after nitrogenase and glutamine synthetase, the third sequential enzyme involved in the assimilation of N2 by intact filaments. However, the kinetics of solubilization of the activity of glutamate synthase during cavitation of suspensions of A. cylindrica indicated that very little, if any, of the activity of that enzyme was located in heterocysts. Concordantly, isolated heterocysts failed to form substantial amounts of radioactive glutamate from either [13N]glutamine or alph-[14C]ketoglutarate in the presence of other substrates and cofactors of the glutamate synthase reaction. However, they formed [14C]glutamate rapidly from alpha-[14C]ketoglutarate by aminotransferase reactions, with various amino acids as the nitrogen donor. The implication of these findings with regard to the identities of the substances moving between heterocysts and vegetative cells are discussed.
TL;DR: A crystalline substance isolated from the active fraction of alfalfa meal increased the dry weight and water uptake of rice seedlings when sprayed on the foliage or applied in nutrient culture.
Abstract: Alfalfa meal and chloroform extracts of the meal have increased the growth and yield of several plant species. A crystalline substance isolated from the active fraction of alfalfa meal increased the dry weight and water uptake of rice seedlings when sprayed on the foliage or applied in nutrient culture. The substance was identified as triacontanol by mass spectrometry. Sprays containing this compound also increased the growth of corn, and barley grown in soil. Authentic triacontanol produced a similar response over a wide range of concentrations on rice grown in nutrient cultures and tomatoes grown in soil.
TL;DR: The authors developed a brief and efficient instrument for assessment, treatment planning, and evaluation of clients by counselors who use Rational Emotive Therapy (RET), which was used to evaluate the performance of participants in a workshop on RET.
Abstract: The purpose of the study was to develop a brief and efficient instrument for assessment, treatment planning, and evaluation of clients by counselors who use Rational Emotive Therapy (RET). Subjects were 235 undergraduate students. Eleven Guttman scales were developed following factor analysis. Each factor is measured by a Guttman scale with a coefficient of reproducibility of 0.90 or greater and with a coefficient of scalability of 0.60. Pre- and posttest scores were obtained for 40 mental health professionals attending an all-day workshop on RET. Over-all test scores were significantly different at the 0.025 level in the predicted direction. There was also a significant difference in the predicted direction between pretest scores of the professionals and the college students. In another study, 87 professionals attending a two day workshop on RET were tested before and after the workshop. There were significant differences in the predicted direction at the 0.025 level or beyond for the overall test scores...
TL;DR: In this paper, the sensitivity analysis presented in this paper is nonlinear and thus permits one to study the effects of large deviations from the nominal parameter values, and since all parameters are varied simultaneously, one can explore regions of parameter space where several parameters deviate simultaneously from their nominal values.
Abstract: Large sets of coupled, nonlinear equations arise in a number of disciplines in connection with computer-based models of physical, social, and economic processes. Solutions for such large systems of equations must be effected by means of digital computers using appropriately designed codes. This paper addresses itself to the critically important problem of how sensitive the solutions are to variations of, or inherent uncertainties in, the parameters of the equation set. We review here, and also present further developments of, our statistical method of sensitivity analysis. The sensitivity analysis presented here is nonlinear and thus permits one to study the effects of large deviations from the nominal parameter values. In addition, since all parameters are varied simultaneously, one can explore regions of parameter space where several parameters deviate simultaneously from their nominal values. We develop here the theory of our method of sensitivity analysis, then detail the method of implementation, and finally present examples of its use.
TL;DR: All species appeared to show less habitat segregation in spring when temperatures rose and food was abundant, and more habitat segregation during the summer when temperatures rise and food is abundant.
Abstract: The seasonal distributions and abundances of 15 littoral zone fish species were determined from May to October 1976 in a small Michigan lake. A team of divers performed seven censuses along a set of transects which encompassed nearly the entire littoral region of the lake; additional dives enabled us to determine vertical distributions and migration patterns to and from overwintering areas. All species appeared to show less habitat segregation in spring when temperatures rose and food was abundant. Species distributions and abundances were quite constant during the summer and considerable habitat segregation was apparent. The bluegill (Lepomis macrochirus) was the dominant species and was studied in greater detail. Small bluegills (<80 mm total length) were confined throughout the year to the vegetation apparently to avoid predation; larger fish moved up in the water column. This species overwintered in two localized regions of tall perennial vegetation in the deep littoral apparently in response...