Showing papers by "Clemson University published in 1978"

The Ecological Significance of Behavioral Dominance

Abstract: In a discussion of the evolution of gene flow, Wilson (1975, p. 103) pointed out that a tendency for different sexes and age groups to migrate differentially can exert a profound influence on social structure. In this paper, I suggest that the reverse is equally true: a basic social structure—namely, the dominance hierarchy—can strongly influence the differential dispersal and migration of different sexes and age groups and thereby serve an important function in population dynamics.

Peroxidase and polyphenol oxidase activities in developing peaches

Abstract: Peroxidase (POD) and polyphenol oxidase (PPO) activities were monitored during the development of peach fruit (Prunus persica Batsch w. Redhaven) from shalk split stage to full maturation. Two extraction methods gave a discrepancy in activity for both enzymes. Two peaks of POD activities were observed and they corresponded to the two weight gain periods of the peaches. Polyphenol oxidase activity was very high at early development stage and declined to a constant level after the pit-hardened stage. Hydrophobic chromatography, using Phenyl-Sepha-rose CL-4B resin, provided a rapid partial purification and characterization of peach PPO. Several apparent forms of PPO and constant changes of these forms during development were observed. Upon cold storage of the acetone powder of peaches, an additional PPO isozyme much more tightly bound to the hydrophobic resin was noted. The technique could be very useful in studies of other food enzymes.

An Empirical Test of a Model of Resistance to Persuasion.

Abstract: This investigation synthesized research from several related areas to produce a model of resistance to persuasion based upon variables not considered by earlier congruity and inoculation models. Support was found for the prediction that the kind of critical response set induced and the target of the criticism are mediators of resistance to persuasion. The more critical acts are focused on arguments presented in a persuasive message, the more likely that the critical act will not be distracting and therefore promote counterarguing which will lead people to be resistant to subsequent persuasive messages arguing on the same side of given attitudinal issue. When criticism is less central to message variables and focuses on speaker and/or delivery characteristics, distraction occurs which decreases the probability of counterarguing and induces people to be vulnerable to forthcoming persuasive messages. This is especially true when negative criticism of speaker characteristics reduces threat to present attitudes and reduces motivation to counterargue to protect privately held beliefs. A completely counterbalanced design employing several manipulation checks was created to rule out competing explanations for differential resistance to persuasion.

Plasma Luteinizing Hormone (LH) and Testosterone Levels during Sexual Maturation in Beef Bull Calves

Abstract: Blood samples were taken by jugularvenipuncture from bullcalvesevery other week from I to 40 weeks of age.Samples were alsodrawn by jugularcannula,every 15 mm for 2 h, from a different group of 4-5 calves at 10 week intervals, from 1 to 40 weeks of age. Following the period of intensive blood collection each group of calves was castrated. Based upon histological examination of the testis, spermatogenesis was initiated after 10 weeks of age, with mature spermatozoa being present in the testis by 40 weeks of age. Body weight and epididymal weight increased linearly with age, while testicular weight increased in a curvilinear pattern, with the most dramatic increase occurring from 30 to 40 weeks of age. Plasma concentrations of LH were low prior to 8 weeks of age, between 10 and 20 weeks of age episodic fluctuations were observed, with a return to low and stable concentrations being seen before a final gradual increase to adult levels at 40 weeks of age. Plasma concentrations of testosterone were variable, but appeared to rise markedly after 28 weeks of age, reaching adult levels by 40 weeks of age. The mode of variation of plasma concentrations of testosterone appeared to resemble that of the adult in 3 of 5 bull calves at 20 weeks of age and all 5 bull calves at 40 weeks of age; more transient peaks were observed at 10 weeks of age.

The rain parameter diagram: Methods and applications

Abstract: A rain parameter diagram is presented which displays the relationships between all rainfall parameters defined in terms of an exponential drop size distribution. Special emphasis is given to remotely measurable quantities such as radar reflectivity, microwave attenuation, and optical extinction. Although an exponential distribution is used to construct the diagram, it is shown to have general application for arbitrary size distributions and for a wide variety of rainfall-related problems. Some of the problems are: analysis of the sources of error which result from the use of empirical rainfall relations; depiction of the physical differences between different types of rainfall and of the similarity between all empirical relations which apply to the same type of rainfall; and determination of the accuracy with which remote measurements must be made to obtain accurate rain parameters. A set of overlays is shown for four common radar wavelengths and four temperatures which display the relationships between microwave attenuation and the other rainfall parameters. These diagrams can be used to determine rainfall parameters remotely in dual-measurement techniques.

Sunset and the orientation of a nocturnal migrant bird

Abstract: THE information required for compass orientation among migratory birds is potentially available in the form of numerous environmental stimuli or cues1. Most passerine migrants complete their annual migrations at night, and their orientation is though to depend on a star compass or one based on geomagnetic stimuli1. The pioneering work of Kramer2 suggested that the setting sun may play a part in the migratory orientation of birds, but this possibility attracted little attention until more recently1. I present here the first experimental evidence that directional information at the time of sunset plays a crucial part in the compass orientation of a nocturnal migrant Passerculus sandwichensis, the savannah sparrow.

Importance of the Daytime Flights of Nocturnal Migrants: Redetermined Migration Following Displacement

Abstract: The daytime flights of nocturnal migrants are examined in relation to the principal axes of migration (P.A.M.) based on calm nights during spring and fall in northwest South Carolina. When nocturnal flights were to the east or west of the calm night directions (30° spring, 232° fall), flights occurred the next morning basically perpendicular to these directions. Because most migrants were displaced east of their P.A.M. in spring and fall, most daytime flights were directed toward the NW, but when nocturnal flights were west of the P.A.M., flights the next morning were to the SE. The daytime redetermined migrations permit the displaced migrants to regain their migratory route by flying the shortest distance.

Interspecific aggression: Toward whom should a mockingbird be aggressive?

Abstract: 1. Interspecific aggression is viewed as a device of behavioral interference employed in resource competition with individuals of other species. Aggression-mediated competition is costly in terms of time and energy invested as well as increased risk of injury or predation. Consequently, natural selection should favor recognition of competitors and differential aggression depending upon the degree of competitive overlap. 2. Mockingbirds (Mimus polyglottos) inhabiting a residential area in the piedmont region of South Carolina (USA) maintain winter feeding territories within which they defend fruit-laden trees and shrubs. Several of the many species occurring with the mockingbird in the study area are frugivorous and represent to varying degrees resource competitors, thus offering an opportunity to study interspecific aggression. 3. Field observations of mockingbird interactions with members of other species reveal that frugivores provoke mockingbird aggression while non-frugivores are essentially ignored. Moreover, the aggressiveness is directly proportional to the extent of frugivory among competitors.

Exact, multiple soliton solutions of the double sine Gordon equation

Abstract: Exact, particular solutions of the double sine Gordon equation in $n$ dimensional space are constructed. Under certain restrictions these solutions are $N$ solitons, where $N\leq 2q-1$ and $q$ is the dimensionality of space-time. The method of solution, known as the base equation technique, relates solutions of nonlinear partial differential equations to solutions of linear partial differential equations. This method is reviewed and its applicability to the double sine Gordon equation shown explicitly. The $N$ soliton solutions have the remarkable property that they collapse to a single soliton when the wave vectors are parallel.

Influence of Resistant Soybeans on the Susceptibility of Lepidopterous Pests to Insecticides

Abstract: In the laboratory, Heliothis zea (Boddie) larvae that were fed foliage of ED73–371, a genotype resistant to the Mexican bean beetle, Epilachna varivestis Mulsant, weighed less and were more susceptible to methomyl and Bacillus thuringiensis Berliner compared to larvae fed foliage of the ‘Bragg’ variety. No difference was detected in the LD50, of methyl parathion when H. zea larvae were reared on Bragg and ED73–371. Larvae of Pseudoplusia includens (Walker) weighed less and were significantly more susceptible to methyl parathion when fed ED73–371 foliage than when fed Bragg foliage, whereas LD60’s of methomyl and B. thuringiensis were similar on the 2 genotypes. Percent control of field populations of H. zea was greater in ED73–371 than in Bragg soybeans when plots of each genotype were treated with similar rates of methyl parathion or B. thuringiensis . Fewer larvae were found in untreated plots of ED73–371 than in Bragg, indicating a lower natural population in the resistant soybeans.

Cytoplasmic estrogen receptors and estrogen concentrations in bovine uterine endometrium.

Abstract: Specific cytoplasmic binding of 17beta-[3H]estradiol ([3H]E2beta) by unoccupied receptors in bovine uterine endometrium was determined by saturation analysis and correlated with endometrium levels of E2beta in 21 cows. The concentrations of these estrogen receptors (ER) during the estrous cycle were significantly greater during proestrus, estrus, and postestrus (days 18-20 and 0-4 of the cycle) than during the midluteal period (days 10-12; P less than 0.05). These increases in ER concentration paralleled increases in endometrial and plasma E2beta concentrations. In a preliminary experiment involving six heifers killed during the estrous cycle, a comparison of the ER concentrations of the horns ipsilateral and contralateral to the corpus luteum showed no significant differences, as did a study of the dissociation constant of the steroid-receptor interaction during the estrous cycle and early pregnancy. The order of inhibition of cytoplasmic binding of [3H]E2beta by estrogens was as follows: E2beta greater than E1 greater than E2alpha greater than E3 at 4 C. The concentration of ER in six pregnant animals was higher on days 2-3 than on days 13-14 after insemination, which was similar to that found in cycling animals; however, the difference between days was not significant. Ovariectomy of two heifers resulted in slightly higher ER concentrations than in intact heifers, whereas immunization of two heifers with an E2beta conjugate resulted in levels 2-fold higher. In these altered animals plasma progesterone (P4) was nearly nondetectable. ER concentration was inversely related to the level of plasma P4 in cycling heifers (r = -0.58, P less than 0.01). Endometrial estrogen and plasma estrogen levels were also inversely correlated with plasma P4 levels (r = -0.65, P less than 0.01 and r = -0.48, P less than 0.05, respectively). Thus, if P4 level influences ER levels, the hormone may make the tissue less responsive to ovarian estrogens at such time as the luteal phase of the cycle and during pregnancy.

Mass transfer characterization of Donnan dialysis

Abstract: Donnan dialysis is a relatively new ion exchange process using ion exchange membranes to permit continuous operation. Potential applications exist in many areas where traditional columnar ion exchange, requiring a regeneration cycle, is currently used. A mathematical model was developed. Mass transfer parameters for the model were determined from laboratory data and correlated with the system operating variables.

Structure changes caused by strain annealing of nylon 6 fibers

Abstract: Experiments are described in which nylon 6 fibers are annealed while subjected to a constant stretch (or slack). Subsequent mechanical and structural measurements are described and analyzed. A paracrystalline structure model is proposed in which folded chains, fully extended chains, partially folded, and partially extended chains coexist in the highly drawn high strength fiber. An explanation of structural changes occurring during the thermal-mechanical treatment is that the folded and partially folded chains are arranged randomly in staggered fashion in small units throughout the structure. During slack annealing, the chains become more folded and shrinkage occurs. Some of the chain refolding will be permanent and may act as new defect sites thereby reducing fracture stress. During annealing in the presence of comparatively high tensile stresses the folded chains are unfolded to some extent, but not completely, and the load-carrying chains in the structure are more uniformly loaded. At the highe...

The influences of weather and topography on water bird migration in the southwestern United States.

Abstract: Radar and visual observations were made on water bird migration throuh the Southwest at six stations from February 1973 through November 1974. The influence of weather on nocturnal non-passerine migration in the Southwest is less significant than reported for passerine migration elsewhere. Both seasonality and weather factors influence water bird migration, but the relative contribution of each is strongly dependent on the specific migration season. Spring migration, which has more extreme weather conditions, shows a stronger correlation to meteorological factors. Autumn migration in the Southwest rarely experiences severe weather, and consequently shows a stronger correlation to seasonality than to weather. The intensity of spring non-passerine migration was highly correlated with height of freezing level, temperature at sunset and midnight, humidity at sunset, cloud height at sunset and midnight, following winds aloft, and inversely related to change in temperature and day of the year. The most important variables listed by the stepwise linear multiple regression analysis were freezing level, following winds aloft, day of the year, and surface wind speed. When the height of the lowest cloud layer was allowed to enter the regression analysis, freezing level and cloud height were the most significant variables, with the intensity of migration higher with higher freezing level and higher cloud base. The most important variables predicting the occurrence or absence of migration were freezing level, barometric pressure and dew point. Autumn water bird migration was most highly correlated with cloud height and day of the year, and inversely correlated with humidity. The most important variables from the stepwise regression analysis and discriminant function analysis were day of the year, 670 m following-wind speed, and temperature. When cloud height was allowed to enter the model, it was the only significant factor influencing migration. As in spring, higher rates of autumn migration occurred with higher freezing levels. More migration occurred on the Great Plains than in the Rocky Mountains; but within the mountains, geography had little influence on the intensity of migration. Indirect evidence indicates that waterfowl and shorebirds move over the mountains (up to 2000 m above the surrounding terrain and 3500 m above sea level), rather than around them.

Phytosterol biosynthesis in ripening tomatoes

Abstract: Phytosterols from mature green tomatoes ripened under red light treatment or in the dark were extracted and quantitated by GLC at 3-day intervals. Tomatoes ripened under light showed 8 phytosterols while those ripened in the dark showed 5 phytosterols. The 4 phytosterols identified and quantitated were cholesterol, campesterol, stigmasterol and β-sitosterol. This is the first time cholesterol was identified in tomato pericarp tissues. Red light treatment advanced and slightly enhanced the biosynthesis of tomato phytosterols in comparison with tomatoes ripened in the dark. Approximately a 10% increase in total phytosterols was noted and the increase was attributed mostly to campesterol and stigmasterol. In mature green tomatoes, the phytosterol content was 37 mg/100g dry wt of which two-thirds was β-sitosterol. As the fruit matured, stigmasterol became the dominant phytosterol with β-sitosterol closely behind. Peak phytosterol content was 106 mg/100g dry tissue at the ripe stage of maturation and the content declined as tomatoes became senescent. The results support the fact that the effect of red light on terpenoids biosynthesis was a general one and was not specific to carotenoids biosynthesis in ripening tomatoes.

A Study of the Accuracy of Some Approximations for t, χ2, and F Tail Probabilities

Abstract: This article summarizes an empirical study on the numerical accuracy of some computational formulas for the tail probabilities of t, χ2, and F distributions, in terms of the maximum absolute error for all p, 0 < p ≤ 1. The results are intended to fill a conspicuous gap in the statistical literature concerning the empirical quality of the approximations, and they are useful for designing efficient and accurate computing algorithms for such probabilities.

d-Ribulose-1,5-biphosphate carboxylase fromThiobacillus neapolitanus

Abstract: d-Ribulose-1,5-bisphosphate carboxylase fromThiobacillus neapolitanus was isolated by differential centrifugation, sucrose density gradient centrifugation, and DEAE-Sephadex column chromatography. The specific activity of the purified enzyme was 2.8 μmol CO2 fixed/min/mg protein. The enzyme's homogeneity was indicated by a single migrating band during polyacrylamide disc gel electrophoresis and as a single symmetrical schlieren peak that sedimented at a constant rate during ultracentrifugation. TheS 20,w was 18.2; the molecular weight, 500,000±20.000. Sodium dodecyl sulfate polyacrylamide disc gel electrophoresis resolved two polypeptide chains of 55,000 and 11,000 daltons. The pH optimum 0f 7.75 with 9 mM MgCl2 shifted to 7.45 with 59 mM MgCl2. Enzyme dialyzed free of Mg++ was inactive and no other divalent cation substituted for Mg++. TheK m (Mg++),K m (CO2), andK m (RuBP) were 0.59 mM, 0.85 mM, and 0.092 mM, respectively. The inhibition by 6-phosphogluconate was competitive and no stimulation of activity could be demonstrated.

A speaker-independent speech-recognition system based on linear prediction

Abstract: This paper describes a speaker-independent speech-recognition system using autoregression (linear prediction) on speech samples. Isolated words from a standard 40-word reading test vocabulary are spoken by 25 different speakers. A reference pattern for each word is stored as coefficients of the Yule-Walker equations for 50 consecutive overlapped time windows. Various distance measures are then proposed and evaluated in terms of accuracy of recognition and speed of computation. The best measure gives 90.3 percent rate of recognition. Both the nearest-neighbor and K-nearest-neighbor algorithms are used in the decision scheme implemented. The computation is minimized by making sequential decisions after a fixed number of iterations. It is observed that computationally this distance measure coupled with a nonlinear time-warped function for matching of windows gives optimal results. The number of speakers was then increased to 105 to show the statistical significance of the results obtained in this project. The recognition rate obtained with the best procedure for 105 speakers was 89.2 percent. The recognition time for this procedure was 9.8 seconds per utterance.

Susceptibility of Certain Soybean Cultivars to Damage by Stink Bugs

Abstract: Five soybean cultivars among 4 maturity groups were tested in 1974 for susceptibility to stink bug damage, primarily by Nezara viridula (L.), Acrosternum hilare (Say), and Euschistus spp. ‘Essex’ matured early and escaped some severe damage before insect populations increased. In 1975, a new method of assessing stink bug damage severity was used to compare damage susceptibility between early (May 22) and late (June 24) plantings of 6 cultivars and one insect resistant breeding line. Damage was more severe among the early plantings, averaging 22.9% seed weight loss compared to 16.0% for the late plantings. Among the late plantings, ‘Cobb’ and ED73-371 incurred significantly less seed weight loss (11.4%) than ‘Bragg’ (23.9%). Differences in damage were not directly related to differences in length of the pod development stages in each case.

Orchard fruit handling system

Abstract: Orchard fruit handling apparatus for conveying and delivering harvested fruit into a plurality of storage bins comprising a first conveyor for adjustable attachment to a conventional farm tractor for receiving and transporting fruit received thereon in a generally linear direction rearwardly of the tractor, and trailer means for attachment to the tractor containing a second conveyor for receiving harvested fruit from the first conveyor and selectively directing the fruit into a plurality of storage bins carried on the trailer A plurality of deflecting blades or bars are selectively positionable across the second conveyor to selectively intercept and deflect the fruit into corresponding bin filler mechanisms located along the side of the second conveyor and above corresponding collection bins Each bin filler mechanism forms a sinuous passageway for gravitationally directing the fruit downwardy into a collection bin and is vertically positionable to maintain its lower fruit discharge outlet at the upper level of the fruit being collected in the storage bin The trailer is provided with means for gravitationally discharging the filled fruit storage bins on to the ground at a central location in the orchard, and the orchard fruit handling apparatus is powered by connection to the hydraulic and electrical systems of the conventional farm tractor