A Survey of Seasonal and Permanent Landowners in Wisconsin's Northwoods: Following Dillman and Then Some     

Greg Clendenning  Donald R. Field  Dana Jensen 《社会与自然资源》2013,26(2):226-237

This article demonstrates the importance of obtaining high response rates for surveys of the general population while illustrating that survey design and procedures that adopt and modify factors known to positively affect survey returns can lead to high response rates, even for a lengthy survey of the general population. Using an expanded version of Dillman's “tailored design method,” we achieved an 82.8% response rate for a general population survey of landowners. When comparing early respondents to late respondents we found significant differences on several sociodemographic variables as well as a number of attitudinal measures central to the research project. In addition, costs are compared between this methodology and a more typical four-wave mailing. Our survey further highlights the importance of improving our understanding of the social changes taking place in rural communities and the implications these changes can have on natural resources management.

This article originally published in Society & Natural Resources, Vol. 17, Issue 5, pages 431–442, 2004. DOI: 10.1080/08941920490430223  相似文献   

Analytical solutions to runoff on hillslopes with curvature: numerical and laboratory verification     

Dana A. Lapides  Cy David  Anneliese Sytsma  David Dralle  Sally Thompson 《水文研究》2020,34(24):4640-4659

Predicting the behavior of overland flow with analytical solutions to the kinematic wave equation is appealing due to its relative ease of implementation. Such simple solutions, however, have largely been constrained to applications on simple planar hillslopes. This study presents analytical solutions to the kinematic wave equation for hillslopes with modest topographic curvature that causes divergence or convergence of runoff flowpaths. The solution averages flow depths along changing hillslope contours whose lengths vary according hillslope width function, and results in a one-dimensional approximation to the two-dimensional flow field. The solutions are tested against both two-dimensional numerical solutions to the kinematic wave equation (in ParFlow) and against experiments that use rainfall simulation on machined hillslopes with defined curvature properties. Excellent agreement between numerical, experimental and analytical solutions is found for hillslopes with mild to moderate curvature. The solutions show that curvature drives large changes in maximum flow rate q_peak and time of concentration t_c , predictions frequently used in engineering hydrologic design and analysis.  相似文献   

Inertial waves in spherical shells at low Ekman numbers     

Ján Šimkanin  Pavel Hejda  Dana Jankovičová 《Studia Geophysica et Geodaetica》2010,54(2):291-298

Inertial waves as oscillatory motions in rotating fluids generate internal shear layers at critical latitudes. We investigated the nonlinear interaction of inertial waves for global flows (3D flows) in dependence on the Ekman number. When the value of the Ekman number decreases, the influence of the Ekman layers to the flow pattern increases. Critical latitudes, the attractor flow pattern and certainly internal shear layers are observable mainly at greater values of the Ekman number. Although, with decreasing the Ekman number smaller flow structures become visible, nonlinear interactions in shear layers drive an axisymmetric flow whose amplitude diverges at the limit of the vanishing Ekman number. We show that this conclusion is valid not only for zonal wind driven by inertial modes but also for similarly driven global flows.  相似文献   

The story of phosphorus: Global food security and food for thought   总被引：12，自引：0，他引：12  

Dana Cordell  Jan-Olof Drangert  Stuart White 《Global Environmental Change》2009,19(2):292-305

Food production requires application of fertilizers containing phosphorus, nitrogen and potassium on agricultural fields in order to sustain crop yields. However modern agriculture is dependent on phosphorus derived from phosphate rock, which is a non-renewable resource and current global reserves may be depleted in 50–100 years. While phosphorus demand is projected to increase, the expected global peak in phosphorus production is predicted to occur around 2030. The exact timing of peak phosphorus production might be disputed, however it is widely acknowledged within the fertilizer industry that the quality of remaining phosphate rock is decreasing and production costs are increasing. Yet future access to phosphorus receives little or no international attention. This paper puts forward the case for including long-term phosphorus scarcity on the priority agenda for global food security. Opportunities for recovering phosphorus and reducing demand are also addressed together with institutional challenges.  相似文献   

Tidal hydrology and habitat utilization by resident nekton in<Emphasis Type="Italic">Pragmites</Emphasis> and Non-<Emphasis Type="Italic">Phragmites</Emphasis> Marshes     

David?T.?OsgoodEmail author  David?J.?Yozzo  Randy?M.?Chambers  Dana?Jacobson  Timothy?Hoffman  Jason?Wnek 《Estuaries and Coasts》2003,26(2):522-533

We compared nekton densities over a range of measured flooding conditions and locations withinPhragmites australis andSpartina alterniflora (salt marsh cordgrass) at the Charles Wheeler Salt Marsh, located on the lower Housatonic River estuary in southwestern Connecticut. Nekton were sampled on nine spring high tide events from May to October 2000 using bottomless lift nets positioned between 0–5 and 10–20 m from the creek edge. Flooding depth, duration, and frequency were measured from each vegetation type during each sampling month. Benthic macroinvertebrate density was also measured within each vegetation type in May, July, and September. Frequency of flooding was 52% lower and flooding depth and duration were also significantly reduced inP. australis relative toS. alterniflora. A total of 4,197 individuals representing 7 species, mostlyPalaemonetes pugio (dagger-blade grass shrimp) andFundulus heteroclitus (common mummichog), were captured.P. pugio densities were significantly greater inS. alterniflora as were benthic macroinvertebrate density and taxa richness during May, but not during June or October. Total fish density was not significantly different betweenP. australis andS. alterniflora and was independent of location on the marsh. Significantly more juvenileF. heteroclitus were collected withinS. alterniflora relative toP. australis in June and July, suggesting that recruitment of this species may be lower inP. australis habitat. Fish density generally did not vary predictably across the range of flooding depth and duration; there was a positive relationship between flooding depth and fish density inS. alterniflora. The measured reduction in flooding frequency (52%) withinP. australis at the Housatonic site would result in an average total monthly fish use, expressed as density, of 447 ind m⁻² forP. australis and 947 ind m⁻² forS. alterniflora. WhenP. australis expansion results in reduction of flooding frequency and duration, nekton community composition can change, access to the marsh surface is reduced twofold, and nursery habitat function may be impaired.  相似文献   

Siderophore adsorption to and dissolution of kaolinite at pH 3 to 7 and 22°C     

Dana R. Rosenberg 《Geochimica et cosmochimica acta》2003,67(2):223-229

Siderophores are Fe(III)-specific ligands produced by many aerobic microorganisms under conditions of iron stress. This study examined adsorption of the commercial trihydroxamate siderophore, desferrioxamine B (DFO-B), to an iron-containing kaolinite (0.1 bulk wt.% Fe) and examined DFO-B effects on initial kaolinite dissolution and iron release rates. Adsorption experiments were conducted at pH 3 to 8 in 0.01-M NaClO₄ in the dark and at 22°C; batch initial dissolution experiments were conducted to 96 h.The adsorption envelope (i.e., adsorption as a function of pH) of DFO-B on kaolinite was consistent with cation-like behavior, with adsorption increasing above kaolinite’s pH_pznpc of 4.9. DFO-B enhanced aluminum release from kaolinite at pH 3 to 7, relative to HNO₃, which is consistent with the ligand’s high binding affinity for Al. Correlation between DFO-B adsorption and aluminum release suggested a surface-controlled, ligand-promoted dissolution mechanism. DFO-B had no effect relative to HNO₃ on silicon release at pH 3 and 5, but moderately enhanced silicon release at pH 7. DFO-B enhanced iron release from kaolinite, with dissolved iron concentrations in the 10-ppb range at 96-h reaction time. These results show that kaolinite may serve as a source of iron to aerobic microorganisms in iron-limited conditions and that siderophores may affect kaolinite dissolution and iron content.  相似文献   

Ocean deserts and ocean oases     

J. Dana Thompson 《Climatic change》1978,1(3):205-230

Desertification can be a particularly visible consequence of climatic change. While considerable research has been devoted to terrestrial desertification in recent years, it is in the sea that biological deserts comprise 90% of the total area. Productive ocean oases or coastal upwelling areas comprise less than .1% of the total ocean area but yield up to half the world's fish catch. Since these high productivity zones occur near coastal margins they are closest to man's pollution and his tools for species decimation.In this paper we examine the notion of biological deserts in the sea and assess the limitation of the ocean as a biological resource. Since climatic conditions favorable for above average ocean productivity are often conducive to the creation of coastal deserts, the connections between ocean and atmosphere in these regions are examined. Finally, the impacts of natural climatic and biological variability, marine pollution, and over-fishing on the process of biological desertification in the sea are explored.Editor's Note: This article was expanded from Chapter 6 in Desertification: Environmental degradation in and around arid lands, edited by M. H. Glantz, Westview Press, Boulder, Colorado, 1977, to whom permission for reprinted material is gratefully acknowledged.Presently at the Naval Ocean Research and Development Activity, Code 322, NSTL Station, Miss. 39529, U.S.A.  相似文献   

Macroseismic effects of the north-Italian earthquake of May 6th, 1976, on the territory of Czechoslovakia     

Dana Procházková  Libuše Ruprechtová  Zdeňka Schenková  Arnošt Dudek  Reviewer J. Janský 《Studia Geophysica et Geodaetica》1977,21(3-4):293-295

Summary The method of treatment of the macroseismic data obtained on the territory of the CSSR after the main 1976 Friuli earthquake is described and the preliminary results are confronted with the geologic structure.  相似文献   

Adsorption of copper and cobalt from fresh and marine systems     

Thomas P. O&#x;Connor  Dana R. Kester 《Geochimica et cosmochimica acta》1975,39(11):1531-1543

The adsorption of copper and cobalt from aqueous solution on to illite and other substrates has been studied as a function of pH, solution composition and solid phase concentration. The results are interpreted in terms of a model whereby the trace metals are adsorbed in exchange for surface bound H⁺ ions. Adsorption varies with solution ionic strength and the concentrations of complex forming ligands; both of these parameters tend to reduce the trace metal adsorption. The Cu²⁺ is two orders of magnitude more reactive toward solid surfaces than Co²⁺ , which is consistent with the general reactivities of these two metal ions. It is also found that Mg₂₊ interferes with adsorption, presumably by competing with the trace metals for the surface sites. A quantitative model was developed which describes adsorption of these metals from natural waters ranging from river water to sea water as a function of pH, complexing ligands and magnesium activity.  相似文献   

Constraints on the origin of Archean trondhjemites based on phase relationships of Nûk gneiss with H2O at 15 kbar     

A. Dana Johnston  Peter J. Wyllie 《Contributions to Mineralogy and Petrology》1988,100(1):35-46

We report the T-X(H₂O) phase relations for the trondhjemitic Nûk gneiss which comprises the principal component of the second phase of Archean (3.0–2.8 by) igneous activity in the Godthåb region of southwestern Greenland. A pressure of 15 kbar was chosen to place constraints on possible protoliths for trondhjemitic melts at lower crustal depths. Under H₂O-saturated conditions, a melting interval of 135° C separates the solidus at 610° C from the liquidus at 745° C. H₂O-saturation at 15 kbar occurs at approximately 15.5 wt % H₂O. The H₂O-undersaturated liquidus extends along a curved path from 745° C at 15.5 wt % H₂O to 1100° C at 2% H₂O. Lower H₂O contents were not investigated. At low H₂O contents (<6%) sodic plagioclase (Pl, An₃₂) is the liquidus phase followed at lower but still near-liquidus temperatures by quartz (Qz) and then garnet (Ga). At 6% H₂O, Ga replaces Pl on the liquidus and is joined at slightly lower temperatures by Pl and hornblende (Hb). The field for liquidus Ga extends to only 7.5% H₂O where it is replaced by Hb which is the liquidus phase up to 13% H₂O. At all higher H₂O contents, epidote (Ep) is the first phase to crystallize, followed by biotite (Bi) at slightly lower temperatures. Following the standard inverse approach, the near-liquidus phase assemblages are interpreted as potential residues from which trondhjemitic melts could be extracted. At high melt H₂O contents (>7%), mafic residues consisting of some combination of Hb, Ga, Ep, and Bi are possible and could correspond to amphibolitic source rocks. At lower melt H₂O contents (< 5%), possible residues consist of Na-Pl+Qz±Ga and could correspond to an earlier generation of tonalitic-trondhjemitic rocks. However, such residues would not impart the highly fractionated REE patterns characteristic of Archean trondhjemites. If a first generation of tonalitic-trondhjemitic melts was generated by higher pressure partial fusion of eclogite and emplaced at 55 km depth, it would crystallize to an assemblage consisting almost entirely of Na-Pl+Qz with highly fractionated REE patterns. These rocks in turn could be partially melted to yield a second generation of trondhjemites which would inherit the highly fractionated REE patterns because neigher Pl nor Qz is capable of significantly fractionating HREE from LREE.  相似文献