Interdisciplinary Experiment Research Articles

Large-scale interdisciplinary experiments inform current and future forestry management options in the U.S. Pacific Northwest

Over the last 20 years, changing public values and increased ecological understanding have led to a paradigm shift in forestry from timber management to sustainable ecosystem management on U.S. federal lands. Forest managers are now seeking alternative management approaches that simultaneously meet socio-cultural, ecological and economic goals. Consequently, many field experiments have become increasingly interdisciplinary and larger in scale or scope. Individually and collectively, these studies in western Washington and Oregon represent major investments by research and land management organizations to enhance the science and understanding for sustainable forest management under increasing public scrutiny and demands for safeguarding healthy environments, conserving biological diversity and providing some level of economic prosperity. They also help to facilitate the transfer of scientific results into practical applications and to realize a more effective interface between science and policy. Questions addressed in this paper include (i) what do we mean by large-scale experiments, (ii) who is investing in these kinds of experiments and why, (iii) where is this information being put to use, and (iv) what does the future hold for these studies?

Unusual transformations in the biosynthesis of the antibiotic phosphinothricin tripeptide

Phosphinothricin tripeptide (PTT, phosphinothricylalanylalanine) is a natural-product antibiotic and potent herbicide that is produced by Streptomyces hygroscopicus ATCC 21705 (ref. 1) and Streptomyces viridochromogenes DSM 40736 (ref. 2). PTT has attracted widespread interest because of its commercial applications and unique phosphinic acid functional group. Despite intensive study since its discovery in 1972 (see ref. 3 for a comprehensive review), a number of steps early in the PTT biosynthetic pathway remain uncharacterized. Here we report a series of interdisciplinary experiments involving the construction of defined S. viridochromogenes mutants, chemical characterization of accumulated intermediates, and in vitro assay of selected enzymes to examine these critical steps in PTT biosynthesis. Our results indicate that early PTT biosynthesis involves a series of catalytic steps that to our knowledge has not been described so far, including a highly unusual reaction for carbon bond cleavage. In sum, we define a pathway for early PTT biosynthesis that is more complex than previously appreciated.

Integrated Ecological and Economic Analysis of Ranch Management Systems: An Example From South Central Florida

Developing sustainable ranch management systems requires integrated research that examines interrelations among ecological and economic factors. In south central Florida, where phosphorus (P) loading is an overriding environmental concern, we established an interdisciplinary experiment to address the effects of cattle stocking density and pasture type on P loading and other ecological and economic factors in subtropical Florida ranchlands through a partnership including ecologists, agricultural faculty, agency personnel, and producers. Here we present an overview of all project components detailed in 3 accompanying papers in this issue of Rangeland Ecology & Management. We describe the experimental design, which included 2 replicates of 4 different cattle stocking density treatments (control, low, middle, and high [0, 15, 20, and 35 cow–calf pairs per pasture]) maintained on 8 improved summer pastures (∼ 20 ha each), and 8 seminative winter pastures (∼ 32 ha each) from 1998 to 2003. Stocking densities did not significantly affect P loads and concentrations in surface runoff, soil chemistry, or soil nematode communities, but did affect cattle production and economic performance. Cattle production was greater at the high than at the middle or low stocking density; economic performance declined significantly with decreasing stocking density (break-even was $1.89·kg-1 for high and $2.66·kg-1 for low density). Pasture type significantly affected environmental factors; average P runoff from improved summer pastures (1.71 kg P·ha-1·y-1) was much greater than from seminative winter pastures (0.25 kg P·ha-1·y-1), most likely because of past P fertilizer use in improved pastures. We integrate results from all the papers within the context of a conceptual model and a P budget, and emphasize that management practices targeted at specific environmental factors on beef cattle ranches, such as nutrient loading, must include consideration of economic impacts and broader ecosystem implications. Desarrollar sistemas sostenibles de manejo de los ranchos requiere de la investigación integrada que examine las interrelaciones entre los factores ecológicos y económicos. En el sur y centro de Florida, donde la carga de fósforo (P) es una preocupación ambiental abrumadora, establecimos un experimento interdisciplinario para estudiar los efectos de la densidad de carga animal y tipo de pradera sobre la carga de P y otros factores ecológicos y económicos en los ranchos subtropicales de Florida el estudio se realizó a través una sociedad que incluyó ecólogos, agrónomos, personal de las agencia y productores. Aquí presentamos detalles del diseño experimental y un punto de vista integrado de los hallazgos del proyecto. El diseño experimental incluyó dos repeticiones de cuatro diferentes tratamientos de densidades de carga animal (0, 15, 20 y 35 pares de vaca-becerro) mantenidos en 8 praderas mejoradas de verano (∼ 20 ha cada una) y 8 praderas de invierno semi-nativas (∼ 32 ha cada una) de 1999 al 2003. Las densidades de carga animal no afectaron significativamente las mediciones ambientales de cargas de nutrientes y las concentraciones del escurrimiento superficial, química del suelo o comunidades de nemátodos, pero afectaron la producción animal y los aspectos económicos. La producción de ganado fue mayor en la densidad alta que en las densidades media o bajas, el comportamiento económico disminuyó significativamente con la disminución de la densidad de carga animal (el punto de equilibrio fue s $1.99·kg-1 para la densidad alta y $2.96·kg-1 para la baja). El tipo de pradera afectó significativamente los factores ambientales, el promedio de P (1.71 kg P·ha-1·año-1) en el escurrimiento de las praderas mejoradas (verano) fue mucho mayor que el de las praderas semi-nativas de invierno (0.25 kg P·ha-1·año-1), muy probablemente debido al uso pasado de la fertilización con P en las praderas mejoradas. Estos resultados enfatizan que las practicas de manejo enfocadas a factores ambientales específicos, como las cargas de P, en los ranchos de producción de ganado para carne necesitan considerar los impactos económicos y las implicaciones a mayor escala en el ecosistema.

Synthesis and Physical Properties of Liquid Crystals: An Interdisciplinary Experiment

This experiment features an investigative approach designed for the introductory science or engineering major and integrates concepts in the fields of chemistry, biology, and physics. Derived from faculty research interests, this novel experiment gives students the opportunity to draw conclusions from tests performed to illustrate the connection between molecular structure and macroscopic properties. The chemical synthesis of the compounds studied further enhances the connection between molecular structure and macroscopic physical properties. The results of two separate physical measurements, refractometry and absorption spectroscopy, are combined to calculate a microscopic, but very practical, property of chiral nematic liquids—the pitch of the helix formed in the liquid crystalline phase. This pitch depends on temperature and composition of the sample exhibiting the liquid crystalline phase, specifically the chiral nematic (or cholesteric) phase. An additional simple measurement using polarized light and a quarter wave-plate can determine the handedness of the helix.

The design and testing of small, low-cost GPS-tracked surface drifters

We have designed and constructed drifters appropriate for use in regions characterized by limited horizontal extent. The drifters follow the upper 30 cm of surface currents, but can be modified to follow water at any depth. The drifters store their latitude and longitude internally, and transmit their current latitude and longitude to a handheld Global Positioning System (GPS)-radio receiver, making their location and subsequent retrieval straight forward A field test of six drifters in Hog Island Bay, Virginia, United States, in August 2003 was successful and led to several design improvements. With simple construction and a total materials cost of under U.S.$200 this design will make drifters an accessible part of interdisciplinary experiments, provide a potentially valuable educational tool, and make experiments that require large numbers of drifters more cost-effective.

Searching for sustainability: interdisciplinary essays in the philosophy of conservation biology

General introduction: an interdisciplinary experiment. Part I. Pragmatism as an Environmental Philosophy: 1. The constancy of Leopold's land ethic 2. Thoreau and Leopold on science and values 3. Integration or reduction: two approaches to environmental values 4. Convergence corroborated: a comment on Arne Naess on wolf policies 5. Pragmatism, adaptive management, and sustainability Part II. Science, Policy, and Policy Science: 6. What is a conservation biologist? 7. Biological resources and endangered species: history, values, and policy 8. Leopold as practical moralist and pragmatic policy analyst 9. Improving ecological communication Part III. Economics and Environmental Sustainability: 10. Sustainability, human welfare, and ecosystem health 11. Economists' preferences and the preferences of economists 12. Evaluating ecosystem states: two competing paradigms 13. The evolution of preferences: Why 'sovereign' preferences may not lead to sustainable policies and what to do about it 14. Sustainability: ecological and economic perspectives Part IV. Scaling Sustainability: Ecology as if Humans Mattered: 15. Context and hierarchy in Aldo Leopold's theory of environmental management 16. Scale and biodiversity: a hierarchical approach 17. Ecological integrity and social values: at what scale 18. Change, constancy, and creativity: the new ecology and some old problems 19. Democracy and sense of place values Part V. Some Elements of a Philosophy of Sustainable Living: 20. Caring for nature: a broader look at animal stewardship 21. Can there be a universal earth ethic? Reflections on the earth charter 22. Intergenerational equity and sustainability Part VI. Valuing Sustainability: Toward a More Comprehensive Approach to Environmental Evaluation: 23. Commodity, amenity, and morality: the limits of quantification in valuing biodiversity 24. The cultural approach to conservation biology 25. Evaluation and ecosystem management: new directions needed? 26. What do we owe the future? An argument for introducing wolves into Adirondack Park 27. Environmental values and adaptive management.

AN EXPERIMENT AT TOR VERGATA UNIVERSITY OF ROME (ITALY)

An interdisciplinary didactic experiment was conducted during 2002 at the Tor Vergata University of Rome (Italy). Four seminars (open to all undergraduates) were held, each involving eight 45-minute sessions and worth four credits (a three-year first degree requires 180 credits overall). The topics of the seminars were ‘Order and Disorder’, ‘Similar and dissimilar’, ‘Time’ and ‘An anatomy of emotions and a language of organs’. The 14 instructors involved belong to the Arts and Sciences faculties. About a hundred students overall enroled in the seminars.

Preparing Social Work Students for Interdisciplinary Practice

Summary This article reports findings of an MSW interdisciplinary practice curriculum experiment. A diverse group of students at ten schools of social work were provided with specialized fieldwork and training. The agencies represented a broad array of services, fields of practice client populations and professional disciplines. Students encountered frequent interdisciplinary disputes and often found social workers coordinating interdisciplinary teams, a role upon which social work curricula rarely focus. This specialized experience seems to have not only enriched students' preparation for interdisciplinary work, but also deepened their understanding of social work as a unique discipline.

Construção de pilhas elétricas simples: Um experimento integrado de química e física

Neste artigo são descritas formas simples e de baixo custo de se montar pilhas, empregando-se placas de zinco, magnésio e cobre mergulhadas diretamente nas soluções eletrolíticas. Como soluções eletrolíticas podem ser empregadas suco de frutas cítricas, ou mesmo apenas água de torneira. A tensão e corrente produzidas pelas pilhas montadas são suficientes para acionar dispositivos com baixa demanda de potência, como relógios analógicos e digitais . Os experimentos podem ser explorados como simples demonstração de transformação de energia química em elétrica para alunos do nível fundamental, ou utilizados como práticas interdisciplinares de Física e Química para alunos mais avançados.

Absorption spectroscopy:: A new approach to estimation of biomass

The results of an interdisciplinary experiment, Modal Lion, which was designed to isolate the effects of absorptivity due to fish with swim bladders from other effects on transmission loss, are described. The experiment was conducted at a 83 m deep site in the Gulf of Lion in September 1995. Absorption losses were measured between 0.6 and 5.0 kHz at a range of 12 km. Trawling operations indicated that the dominant fish in this region were 16.5 cm long sardines. Absorption lines were evident at 1.3 kHz (18 dB) when dispersed sardines were near the surface at night, and at 2.7 kHz (35 dB) when sardines were dispersed near the bottom at dawn just prior to school formation. In addition, an absorption line attributed to 6.5 cm long, dispersed juvenile sardines was evident at a frequency of 3.9 kHz (8 dB) at night. Measured resonance frequencies of 16.5 and 6.5 cm long dispersed sardines at night were in good agreement with theoretical computations based on swim bladder dimensions derived from trawling operations. Results suggest the possibility of spectral separation of juvenile from adult fish, and long term monitoring of the growth and mortality rates of juveniles with absorption spectroscopy measurements.

An Investigation into Processes Influencing the Morphodynamics of an Intertidal Mudflat, the Dollard Estuary, The Netherlands: I. Hydrodynamics and Suspended Sediment

As part of an interdisciplinary experiment, a series of measurements have been obtained on the mudflats of the Dollard Estuary, the Netherlands. The aim was to investigate the sediment transport and accumulation processes occurring during the covering and uncovering of the mudflats, particularly as the area was known to be ebb current dominant. Current velocity measurements confirmed the ebb dominance, and suspended matter concentrations measured over several tidal cycles in calm weather revealed that the highest concentrations occurred at the beginning of the flood and the end of the ebb. The resulting sediment flux, however, was flood dominant. During windy weather the balance of flux changed to ebb dominance. Measurements of floc size and settling velocity show a major organic component produced by entrainment of a thin surface layer during the early flood tide. During a windy period settling velocities in the adjacent channel together with the concentration variations showed a phase lag with water depth and velocity. The highest settling velocities occurred at about slack water, and there were residual ebb fluxes of suspended sediment. It is concluded that the ebb dominance of the currents is not apparent in the sediment fluxes during calm weather, but in periods of high winds the flux is likely to be ebb directed, except when diatom productivity is high. The overall response is similar to that of flood dominated mudflats.

The Leeuwin Current in the Parallel Ocean Climate Model and applications to regional meteorology and fisheries

AbstractUnlike other currents along the subtropical west coasts of continents, the Leeuwin Current off Western Australia transports warm, fresh tropical waters poleward and is strong enough to overwhelm the upwelling tendencies of the coastal wind stress. The representation of this unusual and important current in the global eddy‐permitting ¼° Parallel Ocean Climate Model (POCM) is examined, and implications for coastal fisheries and regional weather and climate discussed. Comparison of POCM fields with those from the Leeuwin Current Interdisciplinary Experiment for austral autumn and winter 1987 suggests that model Leeuwin Current is consistent with these observations in terms of its location and depth distribution, surface gradients and meridional variation in mixed layer depths but is a bit weaker, warmer and fresher. The model Leeuwin Undercurrent is similar in strength to that observed during autumn/winter 1987. Similar to satellite observations, the model Leeuwin Current displays a number of meander, eddy and offshoot features. The frequency distribution and length scales of the model features are generally consistent with estimates of these parameters derived from the satellite images. It is concluded that POCM output can be usefully applied to improve understanding of the Leeuwin Current and associated regional impacts. Copyright © 1999 Royal Meteorological Society

The Canterbury Tales in English and History Class: An Interdisciplinary Experiment

The Canterbury Tales in English and History Class: An Interdisciplinary Experiment

Interdisciplinary experiments with polarized 3He

Optical pumping of metastable 3He atoms is a very efficient method to produce large quantities of nuclear spin-polarized 3He. Recent developments in mechanical compression of the gas, its storage and transport allow for its flexible use in different fields of physics and applied science. Among these are (1) scattering experiments of polarized beams from polarized 3He-targets, (2) 3He as neutron spin filter to polarize neutron beams at research reactors, and (3) polarized 3He gas inhaled into the lungs to perform magnetic resonance imaging. The paper discusses the different topics along with results obtained in a first round of experiments.

A cadmium budget for the German Bight in the North Sea

For the German Bight a cadmium budget has been set up, compiling data from several interdisciplinary experiments during the last years (ZISCH, PRISMA, KUSTOS and TUVAS). The largest pools are contained in the sediments of the German Bight. The advective transports carry large amounts of cadmium through the German Bight. It seems that less cadmium leaves the area than enters, thus increasing the sediment load. During the production season the phytoplankton may absorb cadmium in an amount of the total dissolved cadmium in the water. After settling, e.g. after the spring bloom, the phytoplankton provides the sediment with new contaminated particulate matter. As the estimates involve great uncertainties, it cannot be decided whether the budget is closed.

A Review of Recent Developments in Estuarine Scalar Flux Estimation

The purpose of this contribution is to review recent developments in calculation of estuarine scalar fluxes, to suggest avenues for future improvement, and to place the idea of flux calculation in a broader physical and biogeochemical context. A scalar flux through an estuarine cross section is the product of normal velocity and scalar concentration, sectionally integrated and tidally averaged. These may vary on interannual, reasonal, tidal monthly, and event time scales. Formulation of scalar fluxes in terms of an integral scalar conservation expression shows that they may be determined either through “direct” means (measurement of velocity and concentration) or by “indirect” inference (from changes in scalar, inventory and source/sink terms). Direct determination of net flux at a cross section has a long and generally discouraging history in estuarine oceanography. It has proven difficult to extract statistically significant net (tidally averaged) fluxes from much larger flood and ebb transports, and the best mathematical representation of flux mechanisms is unclear. Observations further suggest that both lateral and vertical variations in scalar transport through estuarine cross sections are large, while estuarine circulation theory has focused on two-dimensional analyses that treatment either vertical or lateral variations but not both. Indirect estimates of net fluxes by determination of the other relevant terms in an integral scalar conservation balance may be the best means of determining scalar import-export in systems with residence times long relative to periods of tidal monthly fluctuations. But this method offers, little insight into the interaction of circulation modes and scalar fluxes, little help in verifying predictive models, and may also be difficult to apply in some circumstances. Thus, the need to understand, measure, and predict anthropogenic influences on transport or carbon, nutrient, suspended matter, trace metals, and other substances across the land-margin brings a renewed urgency to the issue of how to best carry out estuarine scalar flux determination. An interdisciplinary experiment is suggested to test present understanding, available instrument, and numerical models.

De la métaphore à la co-construction. Coopération intelligence artificielle/psychologie pour la conception d'une expérimentation commune

From metaphor to co-construction, the common design of an experiment in artificial intelligence and cognitive psychology. The goal of the Comperobot project is the construction of a machine which is able to maintain an effective dialogue with a child. The second one, more fundamental, is to propose a model of the dialogic activity through several dimensions : interaction, introspection, learning. The analysis, the design and the results of a primary interdisciplinary experiment are described in this paper.

Comparison of the Semtner and Chervin eddy-resolving global ocean model with LUCIE and satellite observations in the Leeuwin Current region

Output from the Semtner and Chervin eddy-resolving global ocean general circulation model is compared with observations from the Leeuwin Current Interdisciplinary Experiment (LUCIE) and satellite data for the coastal waters of Western Australia. The model output is a snapshot over the domain 9-43�S, 90-120�E for a day in mid July 1987, which is during the season that the Leeuwin Current is expected to be well established along the western and southern coasts of Western Australia. Maximum Leeuwin Current velocities in the model are of the order of 60 cm s-1 and are found in the southern part of the current on the western coast and around into the Great Australian Bight. At depths below about 200 m, and centred near 400 m, there is an equatorward-flowing undercurrent with maximum velocity of order 25 cm s-1. Comparison of temperature and salinity cross-sections with LUCIE observations reveals that the model output for this day exhibits many realistic features. In particular, the model fields display a number of prominent meanders and eddies on the Leeuwin Current as well as further offshore. Consistent with observations, mesoscale features associated with the Leeuwin Current are concentrated between 25�S and the Cape Mentelle region; the flow in the northern part of the Leeuwin Current and the North West Shelf may be too weak to induce eddy-generating instabilities. Prominent in the model output are two large meanders on the Leeuwin Current between 25�S and 29�S and two anticyclonic eddies further downstream; features similar to these are evident in satellite data during winter 1987.

Liming induced stimulation of the amino acid metabolism in mycorrhizal roots of Norway spruce (Picea abies [L.] Karst.)

Localization and activity of three enzymes involved in the amino acid metabolism of ectomycorrhizas were investigated within an interdisciplinary experiment performed in a mature Norway spruce stand in Southern Germany (Hoglwald). The enzymes NAD-glutamate dehydrogenase and aspartate aminotransferase were present in root cells, whereas aminopeptidase was found in mycorrhizas of Norway spruce such as “Piceirhiza nigra” and those with the fungi Cenococcum geophilum, Elaphomyces sp., Russula ochroleuca and Tylospora sp. Mycorrhizas growing in the humus layer contained about double the amount of protein found in those taken from the upper mineral soil (0–5 cm).

Topography and the water cycle in a temperate middle mountain environment: the need for interdisciplinary experiments

Two main characteristics of mountainous regions are the large topography-driven lateral redistributions of water and energy, and the considerable topography-related heterogeneities on all scales. These features are difficult to estimate, to incorporate into hydrologic models and to aggregate on the general circulation model grid scale. On the local scale, the topography controls the spatial patterns of water and energy inputs, soil water properties and soil moisture. On the massif scale, the topography induces climatic and ecological gradients that influence the patterns of parameters and fluxes. This is illustrated by results obtained in the Ringelbach and Fecht research catchments of the Vosges massif, France. A better understanding of the water cycle in mountains requires specific interdisciplinary field experiments, as part of international programmes such as WCRP-GEWEX, IGBP-BAHC and UNESCO-IHP, using a combination of altitudinal transects and nested catchments, and including a long-term component, which is necessary for model validation. Some of the specific scientific and methodological problems that remain to be solved for these regions are given. A west-east transect across the southern part of the Vosges massif and the Rhine graben could provide a convenient site for such an experiment in a temperate middle mountain environment.