Search Results - (Author, Cooperation:J. Reese)

2018-03-05

Hindawi

1687-7969

1687-7977

Physics

2014-05-17

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Caenorhabditis elegans/genetics/metabolism/*physiology ; Caenorhabditis elegans Proteins/genetics/*metabolism ; Environmental Exposure ; Female ; *Fertilization ; Male ; Neurons, Afferent/*physiology ; Neurosecretory Systems/physiology ; Oocytes/metabolism/physiology ; Ovum/metabolism/physiology ; Perception ; Pheromones/*physiology ; Prostaglandin-Endoperoxide Synthases/metabolism ; Prostaglandins/biosynthesis ; *Sperm Motility ; Spermatozoa/*physiology ; Transforming Growth Factor beta/genetics/*metabolism

1573-5117

benthic macroinvertebrates ; colonization ; succession ; reservoir ; impoundment ; mainstream ; United States ; Southeast

Springer Online Journal Archives 1860-2000

Biology

Abstract The purpose of this study was to examine the colonization and succession of benthic macroinvertebrates in shallow areas (〈7 m) of Lake Anna, a new mainstream impoundment in the southeastern U.S.A. Benthic macroinvertebrates were sampled for the first three years after filling by means of artificial substrates placed on the bottom and retrieved with SCUBA. Lake Anna was well colonized by benthic macroinvertebrates during the summer season immediately after impoundment. The total density of organisms increased in each of the first three years. Major changes in the fauna occurred between the first and second years, but the changes between the second and third years were more subtle. The fauna could be divided into two distinct groups based upon the time when the organisms were most consistently abundant. The first colonizers appeared to be dependent upon the components of the former terrestrial ecosystem for food and habitat. As autochthonous factors began to regulate succession, diversity increased and the dominant species shifted to an assemblage of second colonizers. These factors included: (1) decomposition of terrestrial vegetation and detritus leaving bare substrate, (2) sedimentation, (3) improved food quality of the organic matter in the sediment because of ingestion and egestion by the organisms themselves, (4) increased plankton populations, and (5) appearance of macrophytes. As the second colonizers became firmly established in the third year, distinct patterns of spatial distribution began to appear among species with similar niches.

Electronic Resource

1573-5133

Stomach fullness ; Tailwater ; Ephemeroptera ; Baetidae ; Diet breadth ; Prey selection

Springer Online Journal Archives 1860-2000

Biology

Synopsis We measured macroinvertebrate densities and abundance, size, and diet of juvenile smallmouth bass, Micropterus dolomieu, at five sites located at varying distances from a metalimnetic release dam. We used these data to determine the influence of high prey abundances on stomach fullness and age-0 year-class strength. Summer diets of juvenile smallmouth bass (27.7–107.7 mm total length) were dominated by Ephemeroptera (primarily Baetidae) but diet composition was highly variable among years and sites. A linear index of prey selection showed that Ephemeroptera were preferred and Trichoptera were avoided at all sites in all years; but, selection indices were not consistent for Chironomidae or Amphipoda and Isopoda. In two of three years, stomach fullness (gut content mass relative to predicted maximum) of juvenile smallmouth bass decreased with distance downstream of the dam, which reflected patterns observed in benthic macroinvertebrate densities. However, in 1989 when flooding and increased turbidity reduced abundances of juvenile smallmouth bass, no differences in stomach fullness were found among sites. High stomach fullness of juvenile smallmouth bass was attributed to high prey abundances near the dam in years of low or normal streamflow. However, patterns in juvenile smallmouth bass abundances in mid-summer could not be attributed to longitudinal variation in prey abundance.

Electronic Resource

1573-5117

macrobenthos ; artificial substrates ; sampling technique ; reservoir ; SCUBA

Springer Online Journal Archives 1860-2000

Biology

Abstract Artificial substrates were compared with a Ponar grab for sampling benthic macroinvertebrates in Lake Anna, Louisa Co., Virginia. The objective was t0 find which technique was best for assessment 0f thermal effluent effects using the following criteria: 1) provide reliable data on density and composition 0f the macrobenthos with a reasonable number 0f replicates; 2) collect the most taxa; and, 3) require the least amount 0f time. Leaves, 3M Corporation's #200 conservation web, and limestone rocks were compared. Each material was tested separately in chicken wire baskets placed 0n the bottom at several depths. Three replicates of each type were retrieved monthly from each depth using SCUBA and cloth flour sacks and compared with grab samples taken from the same depths. Lesser amounts of these materials were tested separately in smaller plastic containers. All large artificial substrate samplers collected significantly more individuals (P = 0.05) and taxa than the Ponar grab. Small web and leaf samplers best met all three 0f the established criteria. The SCUBA system developed in the study is a fast and reliable sampling method.

Electronic Resource

2018-01-05

Genetics Society of America (GSA)

2160-1836

Biology

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Studies were carried out to find appropriate techniques for securing a suitable karyotype from a population of Fundulus diaphanus in the Hudson River and to compare it with a published karyotype of a population of the same species from the New Haven, Connecticut area. A modification of the basic method of Denton & Howell proved to be a simple, effective and inexpensive approach for acquiring numerous and distinct chromosomal spreads for detailed karyotype analyses. The two karyotypes were identical in modal number, arm number and number of submetacentrics; however, they differed in numbers of acrocentrics and secondary constrictions. These differences may indicate incipient chromosomal evolution with the two distinct environments acting as selective agents. Preliminary work was carried out with banding techniques; the modified Denton & Howell method with banding appears to be an effective and promising direction for fish cytogenetics.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The influence of concomitant antacid administration on the relative bioavailability of the H2-receptor antagonists cimetidine, famotidine, nizatidine and ranitidine, was investigated in a panel of 21 healthy, adult male volunteers in an eight-way crossover trial. Administration with antacid reduced the bioavailability of all agents tested. The reduction in area under the serum concentration-time curve (AUC) was greatest for cimetidine (23%) and ranitidine (26%) and least for nizatidine (12%) and famotidine (19%). Reductions in peak serum concentration (Cmax) followed a similar pattern. The times of peak serum concentrations were not affected by antacid. Comparison of the relative bioavailability among all drugs tested showed no statistically significant differences in the effect of antacid administration on these agents. However, a high degree of intersubject variability was observed.

Electronic Resource

0014-195X

English, American Studies

ÉTUDES CRITIQUES

1436-6304

Springer Online Journal Archives 1860-2000

Mathematics

Economics

Electronic Resource

1436-6304

Springer Online Journal Archives 1860-2000

Mathematics

Economics

Electronic Resource

1436-6304

Springer Online Journal Archives 1860-2000

Mathematics

Economics

Electronic Resource

1436-6304

Springer Online Journal Archives 1860-2000

Mathematics

Economics

Electronic Resource

1570-7458

Greenbugs ; Schizaphis graminum ; electronic feeding monitor ; corn ; DIMBOA

Springer Online Journal Archives 1860-2000

Biology

Résumé Le comportement alimentaire du biotype E de S. graminum, provenant de souches maintenues soit sur maïs (OH45), soit sur sorgho (NC + 630X) a été examiné sur 4 cultivars de maïs (Antigua, AP670, OH45 et 2570), un sorgho sensible (NC + 630X) et un résistant (PI264453), à l'aide d'un enregistreur électronique à programme d'analyse. La fécondité et la poids ont été analysés séparément. Les résultats des souches on été comparés en fonction des cultivars, et les relations entre comportement alimentaire, fécondité et poids analysées. Le comportement alimentaire des différentes souches sur sorghos résistants et sur 2 cultivars de maïs (2570 OH45) ont divergé, mais pas toujours dans la même direction. Par exemple, les insectes élevés sur maïs ont consommé plus facilement le sorgho résistant que ne l'ont fait les insectes élevés sur sorgho, tandis que le contraire a été observé avec le maïs OH45. Les 2 souches ont montré le même comportement alimentaire sur les différents cultivars. Le maximum de temps à été consacré à s'alimenter sur sorgho résistant et le moins sur le maïs AP6.70. Bien qu'il n'y ait eu aucune différence entre les comportements alimentaires des souches élevées sur maïs et sur sorgho, elles ont présenté des différences de poids et de fécondité. Ces résultats ont montré l'absence de corrélation entre l'ingestion de phloème (PI) et le moment de la première consommation de phloème (CPI) d'une part, et la fécondité d'autre part. Sur tous les cultivars, les insectes élevés sur maïs ont toujours été au moins aussi féconds que ceux élevés sur sorgho. Il en est de même pour le poids de leurs descendants, bien que les insectes élevés sur maïs pèsent moins sur leur hôte propre (OH45) que les insectes élevés sur sorgho sur leur hôte propre (NC + 630X). Les corrélations entre poids et fécondité ont été positives dans les 2 souches et pour tous les cultivars, mais les 2 souches ont été plus fécondes et ont gagné plus de poids sur sorgho et sur le cultivar Antigua de maïs que sur les autres cultivars de maïs. Or, les sorghos et le maïs Antigua sont considérés comme manquant de DIMBOA, qui doit être vraisemblablement présent dans les autres cultivars de maïs. DIMBOA est undacide hydoxamique commun dans le maïs connu pour réduire la fécondité, la survie et la prise de nourriture des hétéroptères. Ces résultats confirment les possibilités de colonisation du maïs par le biotype E de S. graminum, bien qu'il ait été plus fécond sur sorgho. Ces résultats suggèrent aussi que les insectes élevés sur maïs sont différents des insectes élevés sur sorgho, par adaptation génétique ou physiologique, avec modification concomitante du poids des adultes et de la fécondité. Par suite de ces différences, les insectes élevés sur maïs sont plus aptes à utiliser le maïs et le sorgho résistant que les insectes élevés sur sorgho. Tout ceci suggère les possibilités de développement d'un biotype dangereux pour le maïs.

Abstract Feeding behavior of biotype E greenbugs from populations maintained either on corn or sorghum was studied on four corn germplasm entries and two sorghums using a computerized electronic insect feeding monitor. Greenbug fecundity and weight were also measured. Both populations showed differences in time to committed phloem ingestion and time spent ingesting phloem among plant entries, but the two populations did not respond similarly to each entry. Corn-reared greenbugs fed more readily on resistant sorghum than did sorghum-reared greenbugs, whereas sorghum-reared greenbugs fed more readily on some corn. Feeding behavior was not correlated with fecundity. Corn-reared greenbugs were equally or more fecund than sorghum-reared greenbugs on all entries. Time to committed phloem ingestion was negatively correlated with adult weight in the corn-reared population. Offspring of corn-reared greenbugs attained equal or greater weight than those of sorghum-reared ones, even though corn-reared greenbugs weighed less on their colony host (OH45) than did sorghum-reared greenbugs on their colony host (NC + 630X). Weight and fecundity were positively correlated across both populations and all entries, but both greenbug populations were more fecund and weighed more on sorghum and Antigua corn than on the other corn entries. The results confirm that biotype E greenbugs can colonize and use corn as a host, although they are more fecund on sorghum. The results also suggest that corn-reared greenbugs are different from sorghum-reared greenbugs because of either genetic or physiological adaptation, with a corresponding change in fecundity and adult weight. The implications of these results for biotype development are discussed.

Electronic Resource

1436-6304

Springer Online Journal Archives 1860-2000

Mathematics

Economics

Summary The immediate use of exact methods for solving vehicle routing problems often seems not quite obvious from practical point of view, as there are too restrictive assumptions in these models. Looking at the routing problems in a chemical firm it is yet shown, how theoretically developed methods can be most helpful, as it concerns practical needs. In a case study the Sweepalgorithm becomes a valuable part of a multiple-stage heuristic procedure. Within this scope it is of special interest that there is no assumption of well-known transportation demand at the beginning of the planning period. The procedure delivers remarkable gains against the past results.

Zusammenfassung Der unmittelbaren Anwendbarkeit existierender Verfahren zur Tourenplanung auf die reale Problemwelt eines Unternehmens sind fast immer enge Grenzen gesetzt, weil theoretische und praktische Bedürfnisse zu weit auseinander liegen. Wie theoretisch entwickelte Verfahren dennoch auch für praktische Zwecke äußerst hilfreich sein können, wird anhand eines realen Problems zur Fahrzeugeinsatzplanung in einem Chemieunternehmen demonstriert. Die hierzu vorgenommene Fallstudie nutzt das Sweep-Verfahren als elementaren Bestandteil einer mehrstufigen Verfahrensheuristik. Vor allem wird dabei auch der Tatsache Rechnung getragen, daß der insgesamt zu bewältigende Transportbedarf zum Beginn des Planungszeitraums noch nicht vollständig bekannt ist. Gegenüber den bisherigen Ergebnissen sind bemerkenswerte Verbesserungen feststellbar.

Electronic Resource

1436-6304

Springer Online Journal Archives 1860-2000

Mathematics

Economics

Electronic Resource

1436-6304

Springer Online Journal Archives 1860-2000

Mathematics

Economics

Electronic Resource

0038-4941

Sociology

BOOK REVIEWS

1432-1114

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract A three-dimensional particle image velocimetry (3-DPIV) system is developed to measure the three-dimensional local flow properties of gas-liquid and gas-liquid-solid fluidization systems. The 3-DPIV system requires one camera to simultaneous record orthogonal views of the flow field created by a special optical arrangement. The 3-DPIV has been successfully calibrated and is capable of providing qualitative and quantitative flow information including three-dimensional, full-field, instantaneous velocities, accelerations and holdups of each phase. In this study, sample results of the application of the 3-DPIV technique to a three-dimensional gas-liquid-solid fluidization system operating in the dispersed bubble flow regime demonstrate that the 3-DPIV technique is an effective instrument in studying the local, transient flow phenomena in multiphase systems.

Electronic Resource

1432-5217

Springer Online Journal Archives 1860-2000

Mathematics

Economics

Electronic Resource