Search Results - (Author, Cooperation:V. Christensen)

2014-10-04

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

*Biodiversity ; *Conservation of Natural Resources ; *Extinction, Biological

2018-10-19

American Chemical Society (ACS)

1528-7483

1528-7505

Chemistry and Pharmacology

Geosciences

Physics

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Data from two internationally co-ordinated survey programmes are used in an attempt to display the events in the early life that took place during the ‘recovery period’ of the North Sea herring Stock, 1979–1986.During the period, an increasing importance of the spawning grounds off Buchan and off Yorkshire is evident from distributions of newly hatched herring larvae. The dramatic changes in relative importance of spawning grounds are traced in the data on both late larvae (6 months old) and juveniles (18 months old). The onset of extended spawning off Buchan and off Yorkshire was followed by increase in distinct groups of late larvae of large mean length, and by enlargement of a group of medium-sized juveniles. It is hypothesized that the identified groups are interconnected. Thus, larvae spawned off Buchan and off Yorkshire are found to have growth rates superior to those attained by larvae from west of Scotland and around the Orkney/Shetland Isles, whereas the relationship is reversed in the juveniles. In the investigated period, larval drift routes exhibited the same trends from year to year, the drift of the northerly spawned larvae being the most variable.Thus, changes in the relative contributions from spawning grounds apparently influence the overall spatial distribution as well as size composition of larval and juvenile North Sea herring. The findings indicate that groups of larvae retain, to a large extent, separate distributions until metamorphosis, and point to larval drift pattern as a determinant of spawning group distinctness.

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Two mass-balance trophic models are constructed to describe the Gulf of Thailand ecosystem (10–50 m depth): one model pertains to the initial phase of fisheries development, and the other to when the resources were severely depleted. The two phases are compared, and changes brought about by fishing discussed. A dynamic simulation model, Ecosim, is then used successfully to reproduce the 1980 state of the fishery based on the 1963 model and the development in catches. In addition the 1980 model is used to predict how the ecosystem groups may bounce back following marked reduction in fishing pressure. Finally, the 1963 model is used to study alternative scenarios for how the fisheries development could take place, notably the effect of exploiting only the resources of larger species. The study validates that the Ecosim model can be used to predict ecosystem level changes following changes in fishing pressure, therefore fishing induced changes can to a large extent explain the changes in ecosystem pools and fluxes observed over time.

Electronic Resource

0025-7273

History

Medicine

News, Notes and Queries

APRIL

0025-7273

History

Medicine

JULY

0025-7273

History

Medicine

News, Notes and Queries

OCTOBER

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Global primary productivity generates annually about 224 x 109 t dry weight of biomass. Of this, 59% is produced in terrestrial ecosystems, the rest in aquatic systems1. Of the terrestrial primary production, 35-40% is presently used by humans, directly (for example, as food or fibre), indirectly ...

Electronic Resource

0304-3800

Ascendency ; Ecosystem maturity ; Exergy ; Stability ; Trophic models

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Electronic Resource

0304-3800

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Electronic Resource

1432-1238

Key words Adhesion molecules ; CVVHD ; Endotoxin ; Granulocytes ; Oxidative burst

Springer Online Journal Archives 1860-2000

Medicine

Abstract Objective: Extracorporeal circulation, such as cardiopulmonary bypass and haemodialysis, has been associated with an activation of the immune system, especially the granulocytes. Continuous veno-venous haemodiafiltration (CVVHD) is used in critically ill septic patients. During CVVHD cytokines are excreted in the ultrafiltrate. But when the membranes used in CVVHD are cultured with granulocytes, the granulocytes are slightly activated. This effect is potentiated by endotoxin. We therefore, in vivo, compared the effect on granulocyte activation of CVVHD with an endotoxin group and a control group.¶Methods: Thirty-one pigs were anaesthetized and mechanically ventilated. In ten pigs CVVHD was performed. Eleven pigs received an infusion of Escherichia coli endotoxin 30 μ/kg–1 and ten pigs served as a control group. The adhesion molecules CD18 and CD62L were measured using monoclonal antibodies. The oxidative burst activity was assayed as superoxide dismutase-inhibitory reduction of cytochrome c. The number of granulocytes in peripheral blood and in the lungs and liver were counted.¶Results: The infusion of endotoxin was followed by granulocytopenia, reduced oxidative burst activity, increased expression of CD18 and decreased expression of CD62L on granulocytes. Accumulation of granulocytes in liver and lung tissue was also noted in this group. CVVHD was only associated with a non-significant decrease in CD62L expression on granulocytes. It did not affect any of the other measured immunological parameters.¶Conclusion: In contrast to endotoxin-induced sepsis, the granulocytes were not activated during CVVHD.

Electronic Resource

1432-1041

citalopram ; antidepressant drug ; pharmacodynamics ; adverse effects ; healthy volunteers

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Medicine

Summary Citalopram, a selective 5-HT uptake inhibitor with antidepressant properties, was assessed in three studies in 12 healthy subjects using a battery of EEG, psychological, subjective and symptomatic measures. Study A involved the administration of citalopram, 20 mg and 40 mg, amitriptyline 50 mg and placebo in single dose using a balanced cross-over design. The test battery was applied before, and 1 and 3 h after each drug. Citalopram decreased slow-wave EEG activity whereas amitriptyline increased power in most EEG wavebands. Citalopram increased tapping rate and symbol copying whereas amitriptyline impaired these and other psychomotor tasks. Subjectively, amitriptyline was much more sedative than citalopram and produced more complaints of dry mouth. Study B comprised the administration of citalopram in the usual clinical dose of 40 mg, amitriptyline in the low clinical dose of 75 mg and placebo, each given for 9 nights using a balanced cross-over design. The test battery was applied on the first morning (pre-drug) and on the morning after the last nightly dose. None of the physiological tests showed any drug effects. Subjectively, citalopram was associated with feelings of shaking, nausea, loss of appetite and physical tiredness; amitriptyline produced feelings of shaking, nausea, loss of appetite, dryness of mouth, irritability, dizziness and indigestion; in general, amitriptyline effects were more marked than those of citalopram. Plasma samples were taken on the last day and plasma concentrations of both drugs and their metabolites were found to be in the expected range for the regimens used. In the third study (C), 12 healthy subjects took similar courses of citalopram, amitriptyline and placebo. On the morning of the 8th day, a test dose of ethanol was given. The battery of tests was given predrug, on Days 4/5 and on Day 8, before and 1 and 3 h after the ethanol. Amitriptyline increased the 7.5–13.5 Hz waveband. Amitriptyline impaired critical flicker fusion frequency, tapping, DSST and reaction time; citalopram affected DSST and immediate memory recall. The subjective and symptomatic effects of the drugs were similar to those in Study B. Plasma concentrations of citalopram, amitriptyline and their desmethylated metabolites were in the expected range for the regimens used. Ethanol had the expected effects, impairing performance and producing sedation. No evidence for potentiation of ethanol and drug effects were found, most interactions being additive, or even with some symptoms subtractive. It is concluded that in clinical use citalopram should have little or no effect on cognitive and psychomotor performance, produce minimal sedation but some nausea, loss of appetite and insomnia. Interactions with ethanol should be unremarkable.

Electronic Resource

0197-8462

microwave radiation ; fertilizing capacity ; turkey sperm ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology

Wiley InterScience Backfile Collection 1832-2000

Biology

Physics

Turkey sperm were exposed to 2.45-GHz microwave radiation in a temperature-controlled waveguide apparatus. Temperature was maintained at either 25 or 40.5 °C. The sperm were exposed for 30 min at a specific absorption rate (SAR) of 10 or 50 mW/g. Following irradiation, the sperm were used to inseminate virgin turkey hens artificially. During the 9 weeks following the single insemination, the following were assessed: mean number of eggs, percentage of fertile eggs, rate of decrease in egg fertility, percentage of hatched eggs, and percentage of early and late deaths. These data demonstrate that, for the conditions used in these experiments, microwave radiation has no effect on the fertilizing capacity of turkey sperm.

4 Ill.

Electronic Resource