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  • 1
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Lifetime reproductive success (LRS) of male (N=103) and female (N= 66) spotted sandpipers (Actitis macularia) was studied for 13 years of a 17-year study at Little Pelican Island, Leech Lake, Minnesota. There was no sex difference in longevity, but females had significantly more mates, eggs, chicks, fledged young, and young returning in subsequent years than did males. Variance in LRS was partitioned into five life-history components: longevity (L), mates per year (M), eggs per mate (E), proportion eggs hatched (H), and proportion of chicks fledged (F). For both sexes, F accounted for the greatest proportion of variance in LRS (males, 43%; females, 47%), followed by L (males, 26%; females, 43%) and H (males, 21%; females, 28%). Positive covariance between H and F was consistent with predator-caused clutch and brood loss. Contrary to our expectations, males had a higher coefficient of variation in reproductive success than did females. This was because males were relatively more likely than females to produce no young.
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  • 2
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We investigated factors affecting annual mating success (MS) and reproductive success (RS) of spotted sandpipers (Actitis macularia) from 13 years of a 17-year study at Little Pelican Island, Leech Lake, Minnesota. Analyses were restricted to ages 1–3. Mean annual female MS varied from 1.3 to 2.7 mates, and the MS pattern was indistinguishable from random. However, female MS increased with age and was affected by arrival date, territory size, and beach size. Female RS also increased with age, and number of mates and year effects were the most significant explanatory variables in each age. Older female RS was increased by priority on a territory and presence of a previous mate. Territory size and beach size varied with population density and did not predictably affect RS. The strong year affect on RS was associated with annual variation in sex ratio and predation. Males produce only one successful clutch per year, so MS greater than one is a result of nest loss and does not increase RS. Neither male MS nor RS changed with age. Male reproductive failure rate varied by year. Given that a male produced young, the degree of RS was affected by year, arrival date, priority on a territory, territory size, and beach size. In years with early-season predation, late arrivals had higher RS; territory and beach size effects varied by year. Neither the presence, nor degree, of female care was associated with male RS. Male RS was more subject to annual environmental variability than was female RS, probably because of relatively low annual potential RS among males.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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  • 4
    ISSN: 1573-4862
    Keywords: EMAT ; non-contact ultrasound ; adhesive bond
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract This paper describes some results on the ultrasonic analysis of adhesively bonded aluminium plates using normal incidence radially polarised shear wave ElectroMagnetic Acoustic Transducers (EMATs). The EMAT system presented here has undergone significant development work and improvements compared to previously published examples.(9,19) The electronic ‘deadtime’ of the system has been reduced to approximately 1 microsecond and the frequency range over which measurements can be taken has been extended. The capability of the technique to detect gross and subtle defects is demonstrated.
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  • 5
    ISSN: 1573-2703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Technology
    Notes: Summary Previous methods of calculating the internal impedance of rectangular and T-shaped conductors have made arbitrary assumptions about the form of the magnetic field. These have led to inconsistencies. A method is developed which necessitates less restrictive assumptions, thereby removing the inconsistencies. Results are compared for typical conductor sizes.
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  • 6
    ISSN: 1432-136X
    Keywords: Key words Harbour porpoise ; Metabolic rate ; Ventilation ; Aerobic dive limit ; Blood oxygen binding ; AbbreviationsADL aerobic dive limit ; BMR basal metabolic rate ; BTPS body temperature and pressure, saturated ; βNB non-bicarbonate buffering capacity ; CCO2 total CO2 concentration ; fH heart rate ; fR breathing frequency (breaths ; min−1) ; IHR instantaneous heart rate ; Mb body mass (kg) ; P50 the partial pressure of oxygen at which 50% of the haemoglobin is saturated with oxygen ; PO2 partial pressure of oxygen (kPa) ; PCO2 partial pressure of carbon dioxide (kPa) ; PEFR peak expiratory flow rate (l  ;  sec−1) ; PIFR peak inspiratory flow rate (l  ;  sec−1) ; RQ respiratory quotient ; Td breath-hold duration (s) ; Tex time for expiration (s) ; Tin time for inspiration (s) ; Ts surface time (s) ; Ttot total duration for one ventilation cycle (s) ; TLC total lung capacity (l) ; Ve minute volume (l  ;  min−1) ; Vt tidal volume (l) ; V˙O2 rate of oxygen consumption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The respiratory physiology, heart rates and metabolic rates of two captive juvenile male harbour porpoises (both 28 kg) were measured using a rapid-response respiratory gas analysis system in the laboratory. Breath-hold durations in the laboratory (12 ± 0.3 s, mean ± SEM) were shorter than field observations, although a few breath-holds of over 40 s were recorded. The mean percentage time spent submerged was 89 ± 0.4%. Relative to similarly-sized terrestrial mammals, the respiratory frequency was low (4.9 ± 0.19 breaths · min−1) but with high tidal volumes (1.1 ± 0.01 l), enabling a comparatively high minute rate of gas exchange. Oxygen consumption under these experimental conditions (247 ± 13.8 ml O2 · min−1) was 1.9-fold higher than predicted by standard scaling relations. These data together with an estimate of the total oxygen stores predicted an aerobic dive limit of 5.4 min. The peak end-tidal O2 values were related to the length of the previous breath-hold, demonstrating the increased oxygen uptake from the lung for the longer dives. Blood oxygen capacity was 23.5 ± 1.0 ml · 100 ml−1, and the oxygen affinity was high, enabling rapid oxygen loading during ventilation.
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  • 7
    ISSN: 1432-0789
    Keywords: Key words Polyphenols ; Feed quality ; Manure quality ; Decomposition ; Nutrient mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Farmers in developing countries cannot afford inorganic fertilizers. Multipurpose tree leaves or livestock manure are major sources of nutrients for soil fertility replenishment. Nutrient release from these organic inputs depends on their chemical composition and on soil properties. This study determined the chemical composition of leaves of four African browse species and manure from goats fed leaves as protein supplements, and their mineralization of C, N and P. Cumulative evolved CO2 was significantly correlated with the initial N content of the organic inputs (r 0.83, P〈0.05) and the C : N ratio (r 0.80, P〈0.05), and was negatively correlated with the lignin : N ratio (r–0.71, P〈0.05). Cumulative P released was negatively correlated with the C : P ratio (r 0.76, P〈0.05) and positively correlated with initial P content of the organic amendments (r 0.76, P〈0.05). Cumulative N mineralized was not significantly correlated with initial N, lignin or P concentrations of the organic inputs. Leaves from Acacia karro and Acacia nilotica had high concentrations of polyphenols, which may have caused immobilization of N in both leaves and manure. Gliricidia sepium leaves had low amounts of soluble polyphenols, a high N content and a high rate of N mineralization, but the manure from goats fed Gliricidia leaves immobilized N. The leaves of all browse species immobilized P, but the manure released P. The results suggested that some browse leaves cannot meet the N and P requirements of crops due to their low P content and prolonged N and P immobilization. However, the manures had higher P contents and rates of P mineralization, which suggested that manure is a good source of P for crops. The implications of these results for nutrient cycling in mixed farming systems is discussed.
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