Showing papers by "Mississippi State University published in 1987"

Ecological Genetics of Insecticide and Acaricide Resistance

Abstract: Mode d'acquisition de la resistance, repartition des individus sensibles et des individus resistants

Social Responsibility, Ethics, and Marketing Strategy: Closing the Gap between Concept and Application:

Abstract: The authors review the concepts of social responsibility and business ethics as well as some of the reasons why their adoption by marketing practitioners has been somewhat limited. An approach is d...

Enhancement of ovulation rate in gilts by increasing dietary energy and administering insulin during follicular growth.

Abstract: Two experiments were conducted to examine influences of dietary energy and insulin on ovulation rate and patterns of luteinizing hormone (LH), follicle stimulating hormone (FSH), glucose, insulin and estradiol in gilts during 6 d before estrus. In Exp. 1, 36 gilts were given altrenogest for 14 d to synchronize estrus. In a factorial arrangement, gilts were fed one of two levels of dietary energy (5,771 or 9,960 kcal metabolizable energy (ME)/d), and given one of two levels of porcine insulin (0 or .1 IU/kg body weight iv every 6 h). Dietary treatments began 4 d before and insulin treatments began 1 d after the last day of altrenogest, respectively, and lasted until 24 h after estrus. Main effect means for number of corpora lutea were 14.0 +/- 1.3 and 17.6 +/- .9 for 5,771 and 9,960 kcal ME (P less than .05), and 14.6 +/- 1.0 and 17.0 +/- .9 for 0 and .1 IU insulin (P less than .05). Number of LH peaks on d 3 was greater for gilts that received 9,960 kcal than 5,771 kcal (3.3 +/- .2 vs 2.7 +/- .2; P less than .05), and for .1 than 0 IU insulin (3.2 +/- .2 vs 2.7 +/- .2; P less than .05). During the first 24 h of sampling, concentrations of LH and FSH were greater (P less than .05) in gilts receiving 9,960 kcal ME plus insulin than for other treatment combinations. Concentrations of estradiol were not affected by treatments. In Exp. 2, two formulations of insulin were evaluated for influence on ovulation rate. All gilts received altrenogest and 9,960 kcal ME/d as in Exp. 1. Then on the first day after altrenogest, seven gilts each received short-acting insulin (as in Exp. 1), long-acting insulin (zinc suspension, 1.0 IU/kg body weight every 18 to 24 h), or served as controls. Ovulation rates were increased (P less than .05) by both insulin preparations (15.6, control; 19.1, short-acting; 18.5, long-acting; SE = 1.2). Concentrations of LH tended to be greater after short-acting insulin, but differences were not significant (P = .13). We conclude that increases in ovulation rate produced by dietary energy and insulin are not necessarily accompanied by changes in gonadotropins or estradiol.

Apparent inability of channel catfish to utilize dietary mono- and disaccharides as energy sources.

Abstract: Purified diets containing equivalent amounts of glucose, maltose, fructose, sucrose, corn starch and dextrin were fed to fingerling channel catfish (Icatalurus punctatus) to compare the growth responses to these various carbohydrates. The best growth response was achieved with dextrin and the next best with corn starch. Fish grew at the same rate when glucose, maltose or sucrose was the only dietary carbohydrate source. Dietary fructose resulted in the lowest growth rate. Feed efficiency and percent retained energy values followed the same pattern as growth rates. These data suggest that the catfish is apparently unable to utilize dietary mono- and disaccharides as energy sources. Oral carbohydrate tolerance tests using glucose, maltose, fructose, sucrose and dextrin were conducted with larger channel catfish. Oral glucose and maltose resulted in a persistent hyperglycemia indicative of a diabetic-like status. Fructose appeared to be poorly absorbed from the intestinal tract and did not appear to be converted to glucose. Oral administration of sucrose was followed by a gradual increase in plasma glucose, with no detectable fructose being absorbed until the 6-h period. Oral dextrin resulted in less than a two-fold increase in plasma glucose, which remained constant from 2 to 4 h after administration and then declined. These observations are consistent with the hypothesis that certain fishes, including the channel catfish, resemble diabetic animals by having insufficient insulin for maximum carbohydrate utilization.

A general three-dimensional elliptic grid generation system on a composite block structure

Abstract: A general three-dimensional elliptic grid generation system is discussed. This system includes automatic evaluation of control functions from an algebraic grid or interpolated from boundary point distributions. Also included is iterative adjustment of control functions for boundary orthogonality. The solution is by point SOR iteration using a field of optimum acceleration parameters. This system is incorporated in a code that can treat any physical configuration by using a multiblock structure with complete continuity across interfaces.

Silicon interactions with manganese and aluminum toxicity in sorghum

Abstract: Silicon fertilization has been shown to alleviate Mn and Al toxicities in some plants. Experiments were conducted to assess the role of different Si levels on the alleviation of Mn and Al toxicity symptoms and on dry matter yields of sorghum [Sorghum bicolor (L.) Moench] grown in nutrient solutions with toxic levels of Mn and Al. Silicon concentration as high as 1780 μM had no detrimental effects on dry matter yields. At high Si levels (2670 and 3560 μM), shoot dry matter yields decreased, but root dry matter yields did not. Plants grown with 3600, 5400, and 7200 μM Mn showed marked visual toxicity symptoms in shoots but no effects on roots, even though root dry matter yield decreased more than shoot dry matter yield. The toxicity symptoms and the dry matter yield reductions caused by 3600 and 5400 μM Mn were partially alleviated by 1780 and 3560 μM Si, whereas no Si level overcame the severe effects induced by 7200 μM Mn. Plants grown with high Al (296 μM) had reduced root dry matter yields. Sil...

Sensory cues and receptors for oviposition by Heliothis virescens

Abstract: When given a choice of cotton (host) and ground cherry (non host) in a close range situation, Heliothis virescens (F.), the tobacco budworm, depends primarily on contact chemoreception and mechanoreception, and not olfaction or vision, to discriminate between these two plant species for oviposition. Further, in the presence of a certain level of hairiness (the non-host plant, ground cherry, has short capitate hairs), the females are capable of discriminating between these two plants based on contact chemosensory cues, if at least one pair of tarsi is intact. The contact chemosensilla on the ovipositor do not seem to be important for this purpose. These results are discussed in relation to the sensory cues and receptors for oviposition in other Lepidoptera, especially moths. Resume Signaux et recepteurs sensoriels intervenant dans la ponte d'Heliothis virescens Les differentes recepteurs sensoriels (chimique, mecanique et visuel) des femelles d'H. virescens ont ete rendus inactifs par traitement a l'acide, anten-notectomie ou peinture des yeux avec un enduit noir du type vernis a ongles, pour etudier le determinisme sensoriel de la selection des hǒtes lors de la ponte; les papillons avaient le choix entre le coton (Gossypium hirsutum), sur lequel ils pondent normalement, et Physalis angulata sur lequel on n'observe pas de pontes dans la nature. Au laboratoire, a faible distance, le choix de H. virescens dependait en premier lieu des mecanorecepteurs et des recepteurs chimiques dits de contact (gustatifs), et non de la vision ou de l'olfaction. En presence d'un certain niveau de pilosite (P. angulata possede de courts poils capites), les femelles choisissent les plantes en fonction de la perception chimique dite de contact (gustation) tant qu'une paire de tarses reste intacte. Les sensilles chimiques de l'ovitube ne semblent pas jouer un rǒle important a cet egard. La discussion a examine ces resultats a la lumiere des processus sensoriels utilises par d'autres papillons.

Three-dimensional unsteady Euler solutions for propfans and counter-rotating propfans in transonic flow

Abstract: An Euler code designed for computing the unsteady, three-dimensional, transonic flow about single-rotating and counter-rotating propfans using dynamic blocked-grids is presented. The algorithm is a finite volume, flux-split, upwind, implicit scheme and solves the equations which have been written in a time-dependent curvilinear coordinate system. Relative motion of the blades for counter-rotating configurations is handled by requiring that grid lines be aligned after each discrete rotation of fore and aft rotor grid blocks. The method by which information is passed across block interfaces, as well as how downstream characteristic outflow boundary conditions which enforce simple radial equilibrium are implemented, is discussed. Comparisons of computed flow-field parameters and propfan performance with experimental data indicate good overall agreement between predictions and measurements.

Monoclonal Gammopathy Associated With Naturally Occurring Canine Ehrlichiosis

Abstract: Clinical, hematologic, and immunologic findings for 14 dogs with Ehrlichia canis monoclonal gammopathy were studied retrospectively. Epistaxis, anemia, thrombocytopenia, hypoalbuminemia, hypergammaglobulinemia, and proteinuria were documented in the majority of these dogs. The serum protein electrophoresis pattern was characterized by a distinct narrow-base monoclonal spike, by a broad-base monoclonal spike, or by a monoclonal spike superimposed on a polyclonal gammopathy. The monoclonal spike disappeared following tetracycline treatment for ehrlichiosis. The long-term prognosis following treatment was generally good. The diagnostic features of monoclonal gammopathy due to myeloma were compared with those of E. canis monoclonal gammopathy. Owing to numerous similarities in clinical, hematologic, and immunologic findings, we conclude that an E. canis antibody titer should be determined in all dogs in which a diagnosis of benign monoclonal gammopathy is contemplated or definitive evidence of myeloma, leukemia, or macroglobulinemia is lacking.

Alligator Feeding Habits: New Data and a Review

Abstract: Nutria (Myocastor coypus) and muskrats (Ondatra zibethicus) are the predominant food items of alligators over 1.5 min length in southeastern Louisiana. Our data and a review of the literature on alligator diets indicate that the mammals are apparently major components of the diet of large alligators over much of their range, with fishes and crusta· ceans being more important to smaller alligators. In areas where alligators (Alligator mississippiensis) coexist with furbearing animals, commercial trappers perceive serious competition between themselves and these reptiles (personal communication; McNease and Joanen, 1977). Managers are aware that such problems may exist, but avai I able data provide a limited basis for informed decisions. Management options are also limited by legal protection afforded alligators over much of their range. Alligators are legally harvested in significant numbers only in Louisiana, and on a more limited basis in Florida and Texas. Previous studies have stated that alligators are largely opportunistic feeders (Mcilhenny, 1935). Neill (1971) lists as prey, with little corroborating evidence, virtually every vertebrate animal sharing the range and habitat of

Biological resistance of southern pine and aspen flakeboards made from acetylated flakes

Abstract: Standard soil block tests can be used for southern pine and aspen flskeboards made with phenol-formaldehyde adhesive if the boards are first leached to remove toxic residual chemicals which inhibit fungal attack. Standard fungal cellar and termite tests can be applied directly without leaching. Flakeboards made from flakes acetylated by a new simplified dip acetic anhydride procedure are resistant to attack by brown-, white-, and soft-rot fungi and tunneling bacteria at acetyl weight gains above 15%. Acetylated flakeboards at 18 to 21% acetyl weight gains are not completely resistant to attack by subterranean termites.

Pyrethroid Resistance in Field Populations of Heliothis virescens (Lepidoptera: Noctuidae) in Mississippi in 1986

Abstract: Laboratory bioassays of Heliothis virescens (F.) larvae from strains collected from cotton and soybeans in Mississippi during 1986 showed LD50’s 5- to 15- and 18- to 23- fold higher for fenvalerate and cypermethrin, respectively, than those obtained from a susceptible laboratory colony. Bioassays of third instars on cotton terminal buds treated with recommended field application rates of fenvalerate and cypermethrin indicated that these resistance levels resulted in 40–56% reductions in mortality of third instars compared with those obtained with a susceptible strain. Similar results were obtained in bioassays of a strain from Texas.

Rabbit husbandry and medicine.

Abstract: This article reviews biological characteristics and husbandry practices affecting rabbit health, with emphasis on nutrition, housing, and breeding. Clinical and therapeutic procedures, zoonotic concerns, and important bacterial, protozoal, and parasitic diseases and reproductive problems are discussed.

Variability of cell surface hydrophobicity among Pasteurella multocida somatic serotype and Actinobacillus lignieresii strains.

Abstract: Pasteurella multocida possesses a characteristically gram-negative ultrastructure, yet its inability to grow in the presence of hydrophobic compounds and the general penicillin susceptibility of genera making up the family Pasteurellaceae suggest a cell envelope having atypical permeability properties. The cell surface hydrophobicity properties of strains representing 15 of the 16 somatic serotypes of P. multocida and three strains of Actinobacillus lignieresii were assessed with hydrocarbon adherence and hydrophobic interaction chromatographic assays. These methods revealed surface hydrophobicity to vary dramatically among strains in both species. No direct correlation was observed with species, growth rate, or susceptibility to the antibiotics oxytetracycline (polar), polymyxin B (amphiphilic), or novobiocin (nonpolar) as measured with MIC determinations. All strains were susceptible to the antibiotics, although A. lignieresii was significantly less susceptible than P. multocida to novobiocin. These data suggest that cell surface hydrophobicity in P. multocida may be influenced by the type of lipopolysaccharide present but is not directly related to permeability of the antibiotics examined. The wide diversity of hydrophobic properties exhibited by strains of both P. multocida and A. lignieresii precludes the use of this parameter as a taxonomic acid.

Biochemical Reference Ranges for Commercially Reared Channel Catfish

Abstract: Reference ranges for serum osmolality and 22 serum constituents were determined for channel catfish (Ictalurus punctatus) reared under commercial conditions in Mississippi ponds for 8 months. The constituents analyzed were sodium, potassium, chloride, calcium, magnesium, inorganic phosphate, urea nitrogen, uric acid, creatinine, glucose, cholesterol, triglycerides, total protein, albumin, total bilirubin, lactate dehydrogenase, γ-glutamyltransferase, aspartate aminotransferase, alanine aminotransferase, creatine transferase, alkaline phosphatase, and α-amylase. Constituent concentrations varied markedly among individual fish, but were unaffected by stocking densities ranging from 9,800 to 19,800 fish/hectare. Glucose and potassium concentrations declined significantly during winter months. Creatinine kinase concentrations were affected by the amount of muscle activity and were especially high in fish that had suffered trauma from other individuals.

Soil surface roughness as influenced by selected soil physical properties

Abstract: Soil surface roughness affects infiltration, the storage of water in depressions on the soil surface, runoff and other processess. Roughness of soil after tillage or cultivation is affected by soil factors such as soil type, soil aggregation, water content and others. Specific soil properties that determine a soil's physical reaction to tillage should be identified, so that mechanistic relationships between those properties and the resultant roughness can be developed. The objective of this study was to determine relationships between soil surface roughness, measured using an MIF parameter (the product of a microrelief index and peak frequency), and water content, bulk density, soil texture, wet and dry aggregate size distributions, aggregate stability, organic matter content and other soil properties, measured after each of3 cultivations throughout a growing season. During the summer of 1984, soil physical properties at depths of 10.8 and 30.5 cm were measured prior to primary tillage, and at the surface immediately before 3 cultivations of soya beans, Glycine max (L.) Merr. An automated, non-contact profiler measured surface profiles along transects, 5 cm apart, of 1 × 1 m plots after each cultivation. With water content and dry bulk density at the soil surface ranging from 0.06 to 0.21 kg kg−1 and from 1.05 to 1.26 Mg m−3, respectively, roughness, as the common logarithm of MIF, ranged from −0.758 to −0.788. Dry and wet bulk density were found to account for 64 and 52% of the variation in the MIF parameter, respectively. Water content at cultivation, and at −33 kPa, accounted for 21 and 22%, respectively, of the variation in surface roughness.

Trust, terrorism, and technology

Abstract: The development of civilization implies an evolution of complex trust mechanisms which integrate the social system and form bonds which allow individuals to interact, even if they are strangers. Key elements of trust are predictability of consequences and an evaluation of consequences in terms of self-interest or values. Values, ethics, and norms enhance predictability. The terrorist introduces an unpredictable event which has negative consequences, thus destroying trust. However, terrorist-like situations occur in day-to-day activities. Technology itself makes the world more interdependent and less predictable. Furthermore, technological “accidents” and disasters, which are also unpredictable and negative, may prompt individuals to perceive technology as if it were a “terrorist.”

Bursal secretory cells: An electron microscope study

Abstract: In addition to lymphocytes, macrophages, and epithelial cells, the bursa medulla possesses a cell we have named the secretory cell. The secretory cell, which makes up approximately 0.5% of the bursal cell population, exhibits an eccentric nucleus with a chromatin pattern similar to that of a small lymphocyte and an elongated cytoplasm with one or more cell processes. The electron-dense cytoplasmic granules of the immature secretory cell are localized around the cytocentrum, while in the mature secretory cell these granules are situated beneath the cell membrane of one process. The granular location endows a polarized appearance to the secretory cell. The surface of the membrane is covered with a finely spotted flocculated substance, which may originate from a granular discharge. The round, ovoid, or irregular-shaped granules reveal a homogeneous or distinctive internal pattern. The cortico-medullary border may be the germinal layer of the bursal medulla. The bursal secretory cell is a modified dendritic cell with possible endocrine functions that may be important in B-cell induction.