Showing papers by "Mississippi State University published in 1988"

Water column productivity attributable to displaced benthic diatoms in well-mixed shallow estuaries

Abstract: We attempted to determine the extent to which benthic diatoms contribute to water column primary productivity in shallow-water estuaries and to elucidate the primary mechanisms responsible for suspending the diatoms. A perliminary study conducted in Mugu Lagoon, California indicated that productivity of ocean water entering the lagoon during flood tides was often several orders of magnitude less than that of the same water mass about 3 h later. Benthic pennate diatoms displaced from the sediments into the water column accounted for the increase. A more detailed study was conducted in Barataria Estuary, Louisiana where, for one month, daily measurements were made of benthic and water column productivity and several other environmental variables. During the month, the relationship between water column and benthic primary productivity varied from strongly negative to weakly negative to positive. K-systems analysis indicated that factors comprised of wave height, meteorological tides, astronomical tides, and benthic productivity and standing crop accounted for the full range of variation in water column productivity. Benthic pennate diatoms, represented an average of 74% of the diatom taxa in water column samples. We conclude that the primary productivity of well-mixed shallow estuarine waters is often greatly aumented by displaced benthic algae.

Louisiana wetland loss: A regional water management approach to the problem

Abstract: Loss of Louisiana's coastal wetlands has reached catastrophic proportions. The loss rate is approximately 150 km2/yr (100 acres/day) and is increasing exponentially. Total wetland loss since the turn of the century has been almost 0.5 million ha (1.1 million acres) and represents an area larger than Rhode Island. The physical cause of the problem lies in man's attempts to control the Mississippi River's flooding, while enhancing navigation and extracting minerals. Levee systems and control structures confine sediments that once nourished the wetlands to the river channel. As a consequence, the ultimate sediment deposition is in deep Gulf waters off the Louisiana coast. The lack of sediment input to the interdistributary wetlands results in an accretion deficit. Natural and human-induced subsidence exceeds accretion so that the wetlands sink below sea level and convert to water. The solution is to provide a thin veneer of sediment (approximately 0.6 cm/yr; an average of 1450 g m−2 yr−1) over the coastal marshes and swamps and thus prevent the submergence of vegetation. The sediment source is the Mississippi River system. Calculations show that 9.2% of the river's annual suspended sediment load would be required to sustain the deltaic plain wetlands. It should be distributed during the six high-water months (December–June) through as disaggregated a network as possible. The problem is one of distribution: how can the maximum acres of marsh be nourished with the least cost? At present, the river is managed through federal policy for the benefit of navigation and flood control. A new policy structure, recognizing the new role for the river-sediment distribution, is recommended.

Fourier series direct method for variational problems

Abstract: A direct method for solving variational problems using Fourier series is presented. An operational matrix of integration is first introduced and is utilized to reduce a variational problem to the solution of algebraic equations. Illustrative examples are also given.

Electroantennogram responses of the mediterranean fruit fly,Ceratitis capitata, to a spectrum of plant volatiles

Abstract: Electroantennograms (EAGs) were recorded from unmated, laboratory-reared, male and femaleCeratitis capitata (medfly) in response to a range of C1 and C2 to C12 carbon chain-length aliphatic alcohols, aldehydes, acetates, and acids, and lactones, some of which are known volatiles from leaves and fruits. A large degree of EAG response uniformity between the sexes was observed, with only eight of the 70 compounds tested eliciting significantly larger amplitude EAG responses from female than male antennae. In general, for the five functional-group series tested, aldehydes and alcohols elicited greater responses than acetates, lactones, and acids. The unsaturated alcohols, aldehydes, acetates, and acids elicited equal or larger amplitude EAG responses than their comparable saturated compounds. For four of the functional-group series tested, the EAG response amplitude was significantly greater for a particular carbon chain length, with responsiveness to primary alcohols and aldehydes peaking at C6, acids peaking at C5-6, and acetates peaking at both C5 and C8. The EAG responses to both the 2- and 3-position monoenic alcohols peaked at C6 and C8, while the secondary alcohols peaked at C7. The greatest EAG responses of all compounds tested were elicited by monoenic C6 alcohols and aldehydes that are constituents of the "general green-leaf odor" that emanates from most plants. The potential adaptive benefit of selective sensitivity to green-leaf volatiles is discussed in regard to foraging behavior of medflies.

Metallization of solar cells with ink jet printing and silver metallo-organic inks

Abstract: A computer-controlled ink-jet printing system for photovoltaic metallization is proposed. Ink-jet printable MOD (metalorganic decomposition) inks of Ag, Bi, Nb, and Ti were synthesized for the photovoltaic study. Computer-controlled ink-jet-assisted metallization for photovoltaics in the low processing temperature range was studied. With a titanium/palladium thin-film underlayer and the multilayer printing method, satisfactory cells for 8.08% average without AR coating were obtained. The effects of thermal processes on the solar cells were investigated. It was observed that appropriate thermal processes could improve the contact resistance and the efficiency of the solar cells, but excess thermal processes would destroy the solar cells. >

Multigrid acceleration of the flux split Euler equations

Abstract: Multigrid acceleration is applied to a flux-split algorithm for solving the Euler equations in three dimensions. The basic algorithm is an implicit spatially split approximate factorization method. The stability and performance of the scheme in comparison to other factorizations are examined. Results are presented for three-dimensional flows that demonstrate substantially unproved convergence with the multigrid algorithm.

Non-negative solutions for a class of non-positone problems

Abstract: In the recent past many results have been established on non-negative solutions to boundary value problems of the formwhere λ>0, f(0)>0 (positone problems). In this paper we consider the impact on the non-negative solutions when f(0)<0. We find that we need f(u) to be convex to guarantee uniqueness of positive solutions, and f(u) to be appropriately concave for multiple positive solutions. This is in contrast to the case of positone problems, where the roles of convexity and concavity were interchanged to obtain similar results. We further establish the existence of non-negative solutions with interior zeros, which did not exist in positone problems.

Comparison of Three Solvent Systems for Extraction of Chlorophyll a from Fish Pond Phytoplankton Communities

Abstract: Chloroform-methanol (2:1 v/v), absolute methanol, and 90% acetone were evaluated for their effectiveness as extractants of chlorophyll a from samples of phytoplankton communities collected from catfish ponds. Chloroform-methanol consistently extracted more chlorophyll a than either 90% acetone or methanol. Precision for the methanol extraction was also unacceptably low, with an average coefficient of variation of 17%. Average coefficients of variation for the chloroform-methanol and 90% acetone extraction procedures were 6 and 5%, respectively. Filtered samples should be steeped in chloroform-methanol for at least 4 h to obtain maximum chlorophyll extraction, and the addition of MgCO3 to the extractant as a buffer is not necessary.

Composite grid generation code for general 3-D regions - The EAGLE code

Abstract: A three-dimensional grid generation code based on a composite block structure is discussed. The code can operate either as an algebraic generation system or as an elliptic generation system. Provision is made for orthogonality at boundaries and complete continuity at block interfaces. The code can operate in two or three dimensions or on a curved surface. The input is structured to be user-oriented, and arbitrary block configurations can be treated.

Application of ink jet technology on photovoltaic metallization

Abstract: Computer-controlled ink-jet assisted metallization of the grid pattern of solar cells with metallo-organic decomposition (MOD) silver inks offers a maskless alternative method to conventional photolithographic thin-film technology and screen-printing technology. This method can provide low-cost, fine-resolution reduction in process complexity by direct ink-jet patterning, avoidance of degradation of p-n junctions by firing at low temperature (350 degrees C), and uniform line film on rough-surface solar cells (unpolished solar cells for low-cost purposes). The metallization process involves jet-printed metallo-organic inks, belt furnace firing, and thermal spiking. With titanium thin-film underlayer as an adhesion promoter and multilayer ink jet printing, solar cells of 8.08% average efficiency without AR coating can be obtained. This efficiency value is approximately equal to that of thin-film metallized solar cells of the same lot. >

Diagnosis of Aelurostrongylus abstrusus and Dirofilaria immitis infections in cats from a human shelter.

Abstract: During a 6-month period, 108 sexually mature stray cats were euthanatized at a humane shelter in Alabama. Aelurostrongylus abstrusus was identified in 20 of the cats (18.5%) by Baermann fecal examination, necropsy, or histologic examination. The Baermann fecal examination was a more sensitive test for aelurostrongylosis than was necropsy or histologic examination. Thoracic radiography was useful in identifying infected cats, but was a less sensitive and more nonspecific method of detection than was the fecal examination. Changes in CBC and serum protein concentrations were not helpful identifying cats with aelurostrongylosis. Six of 17 (35%) heartworm-free, lungworm-infected cats had antibodies to Dirofilaria immitis, as determined by an ELISA method, but none had circulating D immitis antigen, as determined by an ELISA method. Three (2.8%) cats had D immitis. Two of the heartworm-infected cats had no detectable antemortem radiographic or clinicopathologic evidence of the infection. Results of ELISA were positive for antibodies to adult heartworms in 2 cats and for circulating heartworm antigen in 2 cats. One cat that had only one heartworm had no detectable circulating heartworm antigen.

A Comparison of Instruments for Assessing Competency to Stand Trial

Abstract: The present study compared two instruments for assessing competency to stand trial, The Competency Screening Test and a revised version of The Georgia Court Competency Test. in a sample of 140 defendants admitted to the forensic unit of a state hospital for court-ordered pretrial evaluation. Scores on the tests were used to predict staff decisions about competency. Correlates of scores on the two tests also were examined. The tests were highly correlated with one another and with the decisions of forensic examiners. Although neither of these instruments should provide the sole basis for competency decisions, both may be useful components of a comprehensive program of competency evaluation.

The relationship of locus of control, age, and sex to life satisfaction and death anxiety in older persons

Abstract: The present study examined Rotter's Internal-External (I-E) locus of control (LOC) concept in relation to life satisfaction and death anxiety in an aged population. Age and sex of the individual were also considered. In the case of life satisfaction, a strong sex and a strong locus of control effect were found. For death anxiety, again a strong sex effect was found, but there was also a significant interaction between locus of control and age. The article suggests the need for a life span developmental perspective in LOC research. Studies which explore the influence of life experiences, situational and environmental variables, and their effect on control orientation are also needed.

Sequence of ontogenetic development and atrophy of the oral apparatus of six anuran tadpoles.

Abstract: The development of the oral structures of six species of anuran tadpoles with four different types of mouth parts and the metamorphic atrophy of these structures in two species with different mouth parts are described. The oral labia of typical tadpoles, oral flaps of microhylids, and lateral oral folds of Rhinophrynus are assumed to be homologous. We also suggest that the barbels of the tadpoles of Rhinophrynus are homologs of the marginal papillae of species with an oral disc. Developmental patterns and sequences of the oral structures of all tadpoles examined follow a common pattern: stomodeal invagination, oral pad development, jaw sheeth delimitation, tooth row ridge development, jaw sheath keratinization, and labial tooth keratinization. Developmental patterns remain constant, while interspecific differences are apparent because of truncations of ontogeny at specific stages. Metamorphic atrophy of oral structures occurs roughly in the reverse order of development, although the procedure is rapid and more haphazard than development.

Patterns of oviducal motility in the cow during the oestrous cycle.

Abstract: Microtransducers sensitive to changes in internal diameter were chronically implanted in the oviducts of 5 dairy cows. Motility patterns were recorded throughout 9 oestrous cycles. Cyclic variations in patterns of motility were observed and compared with circulating concentrations of plasma progesterone. Luteal-phase motility patterns were of low amplitude and frequency. The frequency and amplitude of motility increased 3-5 days before behavioural oestrus. This activity consisted primarily of longitudinal muscle contractions, with an interspacing of circular muscle activity occurring during oestrus. Patterns of activity after oestrus were similar to those before oestrus, with activity decreasing 3-5 days after oestrus. Transducers implanted bilaterally in 2 animals permitted observation of asynchronous patterns between right and left oviducts. Preliminary data suggested a higher level of activity in the oviduct ipsilateral to the active ovary. These variations may be due to a local effect, possibly mediated by the functional ovary or the ovum.

Three-dimensional adaptive grid generation on a composite-block grid

Abstract: The EAGLE three-dimensional composite-block grid code has been extended to an adaptive grid to be coupled with a PDE solver. Both the adaptive control function formulation and the variational formulation were evaluated, and the former was found to be much faster and somewhat more effective. Results for the code coupled with an implicit Euler solver for a three-block configuration on a finite wing are compared with experimental data for transonic flow

The competitive position abroad of products and marketing practices of the united states, japan, and selected european countries

Abstract: Introduction Growing internationalization during the past three decades has become one of the most pervasive influences in business today. This is true for both the export manager responsible for positioning a firm's products in various foreign markets and for the marketing executive responsible for managing the competitive interaction of a firm's products with foreign products in a particular domestic market. As a consequence, the impact of national boundaries on the marketplace has continued to diminish. To compete successfully in this broad arena, marketing managers must have a thorough understanding of, and empathy for, the different needs and preferences of consumers in the various markets within which a firm interacts. Consumer attitudes toward both products and the related marketing practices naturally have a major influence on purchase behavior. In addition, consumer attitudes toward products from different countries can be a major factor in determining successful marketing strategies. We will present here a longitudinal analysis of the general attitudes of consumers in a foreign country, Finland, toward the products imported from the United States, japan, and selected European countries. We will also compare these consumer attitudes toward various dimensions of the related marketing mix strategies. It should be noted that the methodology for analyzing export opportunities is applicable by any company for any foreign country.

Anesthesia in Fish

Abstract: Fish should be anesthetized during any procedure that is stressful or likely to cause pain The author discusses methods of anesthesia, the effects of anesthetic agents on water quality, and the physiologic effects of selected anesthetic agents on fish

Iran and the United States: A Cold War Case Study

Abstract: Richard Cottam served in the U.S. embassy in Tehran from 1956 to 1958 and was consulted by the Department of State during the 1979 hostage crisis. This book draws upon his expert personal knowledge of Iranian politics to describe the spiraling decline of U.S.-Iranian relations since the cold war and the political consequences of those years U.S. policy, he argues, is flawed by ignorance, inertia, the tenacity of a cold war mentality, a quixotic tilt toward Iraq, and the blatant inconsistency of the Reagan administration's arms-for-hostages scheme that produced the Iran-contra scandal.

The use of disparaging humor by group leaders

Abstract: This study examined the effects of humor used by a group leader in terms of the target of the humor. The results indicated that the leader who used self‐disparaging humor was perceived as more effective at relieving tension and encouraging member participation, and appeared more willing to share opinions. The leader who used superior‐targeted humor received lower ratings on helpfulness to group communication and willingness to share opinions. The leader who used subordinate‐targeted humor received lower ratings on social attractiveness and as a tension reliever and summarizer of members’ input. In some instances, the leader who used no humor received higher ratings.

Use of a discontinuous Percoll gradient technique for the separation of channel catfish, Ictalurus punctatus (Rafinesque), peripheral blood leucocytes

Abstract: The use of a discontinuous density Percoll gradient in the separation of channel catfish peripheral blood leucocytes is described. The procedure yielded fractions enriched in monocytes and lymphocytes at the 1·060–1·065 g/ml interface, lymphocytes at the 1·065–1·070 g/ml interface, and neutrophils at the 1·070–1·080 g/ml interface. Cell purities among fractions ranged from 14·4–51·6% for monocytes, 61·4–72·8% for lymphocytes, and 60·4–79·2% for neutrophils. Factors influencing the outcome of the separation procedure include the use of pooled blood samples and calcium- magnesium-free salt solutions.

Vertical transmission of channel catfish virus.

Abstract: Channel catfish broodfish were examined nondestructively for the presence of channel catfish virus (CCV), using a nucleic acid-probing technique. A dot blot assay was tested and shown to be accurate and rapid in the diagnosis of CCV. Two CCV-positive fish were successfully mated, and fertilized eggs were collected. Offspring that hatched were tested and were shown to have CCV. This result indicated vertical transmission of CCV, a herpesvirus.

Wound Healing of Incisions Closed with a Cyanoacrylate Adhesive

Abstract: Young channel catfish Ictalurus punctatus were incised through the peritoneal wall and the wounds were closed with a cyanoacrylate adhesive. Postoperative survival of test fish was 100% compared to 87% for control fish (fish that were handled like test fish but not incised). There was no difference in postoperative bacterial infection rates between test and control groups. Histological evaluation showed that wound healing was essentially complete within 14 d of surgery. Inflammatory responses were minor during this time and absent by day 14. Adhesions between incised tissue and the peritoneal viscera were observed in 60% of test fish; these adhesions slowed but did not alter the course of wound healing.

Influence of an immobile or mobile saturation on non-Darcy compressible flow of real gases in propped fractures

Abstract: The effects of immobile and mobile liquid saturations on the non-Darcy flow coefficient in propped fractures have been investigated. It was observed that an immobile liquid saturation of up to 20% PV can triple the non-Darcy flow coefficient and a small mobile liquid saturation will increase the non-Darcy flow coefficient by nearly an order of magnitude (over that of the dry case). The linear relationship between the logarithm of the non-Darcy flow coefficient and the logarithm of the proppant permeability for propped fractures, as proposed by Cooke, is shown to be invalid in the presence of an immobile or mobile liquid saturation. Constants are presented that can be used to obtain a more accurate approximation than has previously been available on the non-Darcy flow coefficient for single-phase flow in fractures propped with 10/20- and 20/40-mesh Ottawa sand. The experimental data obtained from this research was compared with those of others reported in the literature.