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  • 1
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Maintenance of estuarine zooplankton populations in large river-dominated estuaries with short residence times has been an intriguing subject of investigation. During three different hydrological seasons, autumn 1990, summer 1991, and spring 1992, we intensively sampled zooplankton populations in the estuarine turbidity maxima (ETM) region of the Columbia River estuary of Oregon and Washington, USA. One of the principal objectives was to investigate retention mechanisms of the predominant zooplankton species, the harpacticoid copepod Coullana canadensis and the epibenthic calanoid copepod Eurytemora affinis. In the ETM, C. canadensis densities mirrored those of turbidity gradients and were almost always greater at the river bed, while E. affinis densities were greater higher in the water column during the flood and lower in the water column during the ebb. Cross-correlation and time-series analyses determined that C. canadensis densities were highly positively correlated with turbidity and that most of the variability was explained by the lunisolar diurnal (K1) and principal lunar (M2) tidal components occurring once every 23.93  h and once every 12.42 h, respectively. This indicates that C. canadensis populations are most probably maintained in the estuary through the same near-bottom circulation features that trap and concentrate particles in the ETM. In contrast, densities of the more motile species E. affinis were highly correlated with negative velocities, or ebb tide, and most of the variability in population densities could be explained by the principal lunar tidal component; therefore, we hypothesize that this species is probably vertically migrating on a tidal cycle into different flow layers to avoid population losses out of the estuary.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1238
    Keywords: Critical care ; Ethics ; Resuscitation orders ; Advance directives ; Life support withdrawal ; Prognosis ; Severity of illness index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objectives To examine the frequency of limiting (withdrawing and withholding) therapy in the intensive care unit (ICU), the grounds for limiting therapy, the people involved in the decisions, the way the decisions are implemented and the patient outcome. Design Prospective survey. Ethical approval was obtained. Setting ICUs in tertiary centres in London and Cape Town. Patients All patients who died or had life support limited. Interventions Data collection only. Results There were 65 deaths out of 945 ICU discharges in London and 45 deaths out of 354 ICU discharges in Cape Town. Therapy was limited in 81.5% and 86.7% respectively (p=0.6) of patients who died. The mean ages of patients whose therapy was limited were 60.2 years and 51.9 years (p=0.014) and mean APACHE II scores 18.5 and 22.6 (p=0.19) respectively. The most common reason for limiting therapy in both centres was multiple organ failure. Both medical and nursing staff were involved in most decisions, which were only implemented once wide consensus had been reached and the families had accepted the situation. Inotropes, ventilation, blood products, and antibiotics were most commonly withdrawn. The mean time from admission to the decision to limit therapy was 11.2 days in London and 9.6 days in Cape Twon. The times to outcome (death in all patients) were 13.2 h and 8.1 h respectively. Conclusions Withdrawal of therapy occurred commonly, most often because of multiple organ failure. Wide consensus was reached before a decision was made, and the time to death was generally short.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1238
    Keywords: Key words Critical care ; Ethics ; Resuscitation orders ; Advance directives ; Life support withdrawal ; Prognosis ; Severity of illness index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objectives: To examine the frequency of limiting (withdrawing and withholding) therapy in the intensive care unit (ICU), the grounds for limiting therapy, the people involved in the decisions, the way the decisions are implemented and the patient outcome. Design: Prospective survey. Ethical approval was obtained. Setting: ICUs in tertiary centres in London and Cape Town. Patients: All patients who died or had life support limited. Interventions: Data collection only. Results: There were 65 deaths out of 945 ICU discharges in London and 45 deaths out of 354 ICU discharges in Cape Town. Therapy was limited in 81.5% and 86.7% respectively (p=0.6) of patients who died. The mean ages of patients whose therapy was limited were 60.2 years and 51.9 years (p=0.014) and mean APACHE II scores 18.5 and 22.6 (p=0.19) respectively. The most common reason for limiting therapy in both centres was multiple organ failure. Both medical and nursing staff were involved in most decisions, which were only implemented once wide consensus had been reached and the families had accepted the situation. Inotropes, ventilation, blood products, and antibiotics were most commonly withdrawn. The mean time from admission to the decision to limit therapy was 11.2 days in London and 9.6 days in Cape Town. The times to outcome (death in all patients) were 13.2 h and 8.1 h respectively. Conclusions: Withdrawal of therapy occurred commonly, most often because of multiple organ failure. Wide consensus was reached before a decision was made, and the time to death was generally short.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 7700-7707 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A new scheme for performing high-resolution kinetic energy measurements on single quantum states of NO is described. Laser excitation of the a 4Π(ν=13–15) and b 4Σ−(ν=3)←X 2Π(ν=0) spin-forbidden bands has been used to produce NO a 4Π, either by direct excitation or after excitation to NO b 4Σ− followed by b→a emission. The sensitivity is compared to previous experiments on CO, employing the forbidden Cameron system. In the course of these experiments, three previously unknown vibronic levels of the a 4Π state were observed for which high precision molecular constants have been obtained. The derived molecular constants have been used to construct a chemically accurate RKR potential for the a 4Π state to within 0.2 eV of the dissociation limit. In addition, the electric dipole moments for the a 4Π(ν=13–14) levels have been determined. By comparing the experimental results with two ab initio calculations, the polarity of the dipole moment of the a 4Π state at equilibrium separation could be determined. A set of supplementary molecular beam laser-induced fluorescence studies on the b 4Σ−(ν=3)←X 2Π(ν=0) band were also carried out. These allowed the fluorescence lifetime of b 4Σ−(ν=3) state to be obtained under collision-free conditions and the electronic origin of the quartet manifold to be determined within 0.03 cm−1. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 50 (1995), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Perennial ryegrass/white clover (Lolium perennel Trifolium repens) pastures of three white clover varieties were compared at UK lowland (Plas Gogerddan, PG) and upland (Bronydd Mawr, BM) sites over three harvest years (1989–91) under continuous variable stocking (ewes and lambs until weaning and lambs thereafter). Mean annual lamb output from small-leaved S 184 (1179 kg ha−1) was 29% greater than that from prostrate small-leaved AberEndura at PG with medium-leaved Huia also giving 19% more output than AberEndura. At BM, output from S 184 (863 kg ha−1) was 19 and 14% greater than that from AberEndura and Huia respectively. The differences in lamb output between the small-leaved varieties owed to a combined effect of higher individual lamb growth rates and greater stock-carrying capacity, both of which were more pronounced in the post-weaning period. The higher output from S 184 relative to Huia at BM was attributed to higher stocking rate, particularly after weaning. Clover productivity and persistence were also studied under three cutting-only managements at PG. Performance under a treatment cut at 2–3 cm every 10 d (T1), which is synonymous with assessment of persistence in UK National List testing, was poor with clover growing point number of only 498 m−2 compared with 4906 m−2 on the grazed sward in autumn 1991. Although productivity and clover content under T3 (cut at 3–4 cm every 42 d — similar to National List yield regime) gave the same varietal ranking as lamb production, there was an under-estimation of the small-leaved varieties, particularly AberEndura, relative to Huia. An intermediate treatment (T2), cut at 3–4 cm every 21 d, also over-estimated the performance of the medium-leaved variety. Herbage data from ground level sampling every 21 d using exclosure cages on the grazed swards were also poorly related to lamb performance. These results highlight the effect of clover variety on lamb production, which appeared to be independent of leaf size, and also confirm the existing problems associated with assessment of white clover varieties using a cutting regime.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 2 (1995), S. 2847-2852 
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temporal evolution of the radial profile of lithium-like oxygen (OVI or O5+) 3d-4f, 52.0 nm emission from 80 ns rise time, 6–16 kA peak current, pulsed capillary discharges in 1 mm diam, 1 cm long polyacetal capillaries, has been studied. Evidence was seen for a central "flattening'' in this emission. Extreme-ultraviolet, time-integrated, pinhole transmission grating spectra were taken of discharges at 16 and 23 kA peak currents in 0.5 mm diam, 1 cm long capillaries. Spectra obtained at the higher peak current (23 kA) showed evidence of helium-like (CV or C4+) and/or hydrogen-like carbon (CV or C5+) resonance line emission (4.0 and 3.4 nm wavelength) filling the capillary diameter. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 41-47 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A phase fluorometer based on a low-cost and versatile high-frequency modulated light source and a fast gain-modulated photomultiplier is described. The apparatus is particularly well-suited to high-sensitivity frequency-domain fluorescence measurements requiring ultraviolet excitation. The system is very compact since it features a directly modulated light source, a miniature photomultiplier tube, and an rf synthesizer on a PC board. Equipped with a suitable fiber optic probe sensor, the device has potential as a portable unit for a wide range of remote sensing applications. The lamp can be modulated at frequencies up to 120 MHz and the phase fluorometer has been tested at up to 70 MHz with a range of fluorescent lifetime standards containing quinine sulfate quenched with sodium chloride. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 2528-2533 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The design and operation of a beam line for transporting and charge-to-mass selecting highly charged ions extracted from the National Institute of Standards and Technology electron beam ion trap (EBIT) are described. This beam line greatly extends the range of experiments possible at this facility. Using the transport system, pure beams of low-energy, highly charged ions up to Xe44+ have been produced with substantially higher fluxes than previously reported from an EBIT source. Design choices and computer modeling for the various components of the beam line are explained in detail. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 3744-3749 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The construction and testing of a dual-channel photon correlator is reported for the frequency domain imaging of fluorescence lifetimes using photon-counting detection. A light source modulated at radio frequency excites fluorescence, which is detected using an imaging single-photon detector. After discrimination, single-photon events are processed in parallel by the correlation circuit, the purpose of which is to allow both the mean phase delay and the demodulation of fluorescence to be calculated relative to a reference signal derived from the modulated excitation source. Outputs from the correlator are integrated in a computer, resulting in accumulation of images which have been statistically filtered by sine and cosine transforms, and which can be manipulated within the computer to generate a resultant image where contrast depends on fluorescence lifetime rather than fluorescence intensity. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 48-51 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Phase fluorometry and fluorescence lifetime imaging require a source of exciting light which can be modulated at radiofrequency. This is difficult to achieve with reasonable efficiency using conventional light sources with external modulators such as Pockels cells, while laser sources are limited in wavelength tunability. In this paper a low-cost and versatile high-frequency modulated light source is described which is well suited to frequency-domain fluorescence measurements. The source is a modified deuterium arc lamp which can be driven directly at frequencies up to approximately 130 MHz, and which provides a highly stable source of ultraviolet and visible light. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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