Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 9 (1990), S. 283-287 
    ISSN: 1432-0789
    Keywords: Nitrogen transformations ; Flooded soil ; Nitrogen loss ; Nitrification ; Dentitrification ; Urea ; NH3 volatilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Laboratory batch incubation experiments were conducted to determine in fate of urea-15N applied to floodwater of four rice soils with established oxidized and reduced soil layers. Diffusion-dependent urea hydrolysis was rapid in all soils, with rates ranging from 0.0107 to 0.0159 h-1 and a mean rate of 0.0131 h-1. Rapid loss of 53%–65% applied urea-15N occurred during the first 8 days after application, primarily by NH3 volatilization. At the end of 70 days, an additional 20%–30% of applied urea-15N was lost, primarily through nitrification-denitrification processes. The soil types showed significant differences in total applied urea-15 recovery. Conversion of urea-15N to N2-15N provided direct evidence of urea hydrolysis followed by nitrification-denitrification in flooded soils.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 32 (1996), S. 0 
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : The ability to predict how streams and wetlands retain phosphorus (P) is critical to the management of watersheds that contribute nutrients to adjacent aquatic systems such as lakes. Field and laboratory experiments were conducted to determine the P assimilatory capacity of a stream (Otter Creek) in the Taylor Creek/Nubbin Slough Basin located north of Lake Okeechobee, Florida. Dominant soils in this basin are sandy Spodosols; landuse is primarily dairy farms and beef cattle pastures. Estimates of P assimilation show that sediments assimilate approximately 5 percent of the P load. Phosphorus assimilation rates in the stream were estimated using first-order relationships based on the total P concentration of the water column as a function of distance from the primary source. This method assumes minimal lateral inputs. Stream lengths required for one turnover in P assimilation were estimated to be in the range of 3–16 km. Laboratory studies using intact sediment cores indicated a P assimilation rate of 0.025 m day−1, and equilibrium P concentration of 0.16 ± 0.03 mg L−1 in the water column. Dissolved P concentration gradients in the sediments showed upward flux of P at water column P concentration of 〈0.16 mg L−1. Approximately 56–77 percent of the P assimilated in the above-ground vegetation during active growth was released or translocated within six months of senesence, suggesting short-term storage in above-ground vegetation. Bottom sediments and recalcitrant detrital plant tissue provide for long-term P assimilation in the creek. Although stream sediments have the potential to adsorb P, high flow rate and low contact period between water and sediment limits this process.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Better understanding of crop responses to projected changes in climate is an important requirement. An experiment was conducted in sunlit, controlled environment chambers known as soil–plant–atmosphere–research units to determine the interactive effects of atmospheric carbon dioxide concentration [CO2] and ultraviolet-B (UV-B) radiation on cotton (Gossypium hirsutum L.) growth, development and leaf photosynthetic characteristics. Six treatments were used, comprising two levels of [CO2] (360 and 720 µmol mol−1) and three levels of 0 (control), 7.7 and 15.1 kJ m−2 d−1 biologically effective UV-B radiations within each CO2 level. Treatments were imposed for 66 d from emergence until 3 weeks after the first flower stage. Plants grown in elevated [CO2] had greater leaf area and higher leaf photosynthesis, non-structural carbohydrates, and total biomass than plants in ambient [CO2]. Neither dry matter partitioning among plant organs nor pigment concentrations was affected by elevated [CO2]. On the other hand, high UV-B (15.1 kJ m−2 d−1) radiation treatment altered growth resulting in shorter stem and branch lengths and smaller leaf area. Shorter plants at high UV-B radiation were related to internode lengths rather than the number of mainstem nodes. Fruit dry matter accumulation was most sensitive to UV-B radiation due to fruit abscission. Even under 7.7 kJ m−2 d−1 of UV-B radiation, fruit dry weight was significantly lower than the control although total biomass and leaf photosynthesis did not differ from the control. The UV-B radiation of 15.1 kJ m−2 d−1 reduced both total (43%) and fruit (88%) dry weights due to smaller leaf area and lower leaf net photosynthesis. Elevated [CO2] did not ameliorate the adverse effects of UV-B radiation on cotton growth and physiology, particularly the boll retention under UV-B stress.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-1009
    Keywords: Drainage water ; Aquatic plants ; Nutrient removal ; Water quality ; Organic soil ; Nonpoint source pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Potential use of reservoirs and flooded fields stocked with aquatic plants for reduction of the nutrient levels of organic soil drainage water was evaluated. The treatment systems include 1) a large single reservoir (R1) stocked with waterhyacinth (Eichhornia crassipes), elodea (Egeria densa), and cattails (Typha sp.) in series; 2) three small reservoirs in series with waterhyacinth (R2), elodea (R3), and cattails (R4), grown in independent reservoirs; 3) a control reservoir (R5) with no cultivated plants; 4) a large single flooded field planted to cattails; 5) three small flooded fields in a series planted to cattails; and 6) a flooded field with no cultivated plants. Drainage water was pumped daily (6 hours a day, and 6 days a week) into these systems for a period of 27 months at predetermined constant flow rates. Water samples were collected at the inlet and outlet of each treatment system and analyzed for N and P forms. The series of reservoirs stocked with aquatic plants functioned effectively in the removal of N and P from agricultural drainage water, compared to a single large reservoir. Allowing the water to flow through the reservoir stocked with waterhyacinth plants with a residence time of 3.6 days was adequate to remove about 50% of the incoming inorganic N. Allowing the water to flow through a series of two small reservoirs, R2 and R3, with a residence time of 7.3 days was necessary to remove about 60% of the incoming ortho-P. Flooded fields were effective in the removal of inorganic N, but showed poor efficiency in the removal of ortho-P.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 39 (1977), S. 143-145 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary During a survey for genetic disorders, L-Xylulosuria, an autosomal recessive condition, was found to affect three cousins in an inbred family. There were no clinical symptoms.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 39 (1977), S. 139-142 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary During routine screening of amino-acid disorders, we detected hypervalinemia in two sibs (a girl of 4 and a boy of 3 years of age) of a consanguineous marriage. There was no excess accumulation or excretion of leucine or isoleucine, which presumably indicates the absence of valine tranxaminase.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of paleolimnology 7 (1992), S. 157-161 
    ISSN: 1573-0417
    Keywords: coring device ; paleolimnology ; sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Flow, turbulence and combustion 31 (1975), S. 279-308 
    ISSN: 1573-1987
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The phenomenon of coupled breathing and longitudinal oscillations of a wedge-mass system in a free stream is examined. As a first step the unsteady pressure distribution on the surface of the oscillating wedge is calculated. For dynamic equilibrium of the wedge-mass system, the moment about the apex of the wedge must be zero. This condition establishes the amplitude and phase relation between breathing and longitudinal oscillations. As a final step the equation of motion of the store is used to calculate the frequency of the breathing oscillations. This frequency is shown to be dependent on four parameters. These parameters include the Froude number, the rigging line length to wedge breadth ratio and the rigging line stiffness and damping. Current results are compared with Hume and Stevens [1] experimental results.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 85 (1981), S. 201-207 
    ISSN: 1573-5117
    Keywords: floating plants ; submersed plants ; emersed plants ; aquatic systems ; physico-chemical parameters ; euthropic lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A field study was conducted during the months of October, January, May, and July (1979–80) to examine the diel variations in dissolved O2 (DO), pH, dissolved CO2, bicarbonate and carbonate alkalinity, NH4-N, NO3-N, and PO4-P concentration, and conductivity (EC) of the water in six aquatic systems. Water in hyacinth (Eichhornia crassipes) ponds showed very little or no diel or seasonal variations in DO, pH, dissolved CO2, and bicarbonate alkalinity. Dissolved O2 concentration of the water under floating hyacinth cover was in the range of 0.2–3.0 µg/ml, while dissolved CO2 levels were in the range of 10–35 µg/ml. In the aquatic systems with no floating vegetation, i.e., elodea (Egeria densa) pond, cattail (Typha sp.) pond, control pond (filamentous algae and Chara spp.), and eutrophic lake (algae in Lake Apopka), DO and pH of the water increased during mid-day and decreased during the night. Dissolved O2 levels in these ponds were in the range of 5–20 µg/ml during mid-day and 2–8 µg/ml during the night, while pH of the water was in the range of 8–9.5 during mid-day and decreased to 7–8 during the night. An inverse relationship was observed between bicarbonate and carbonate alkalinity of the water in the aquatic systems with no floating vegetation while no carbonates were detected in the water with floating hyacinth plants. Ammonium N, NO3-N and PO4-P concentration of the water in these aquatic systems showed very little or no diel variations.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...