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31.
In this paper, we present a reflexive examination of how and why we, an academic and a practitioner, arrive at different evaluations of collaborative progress in natural resource management. We situate this examination in our long-standing involvement in designing, adaptively managing, and participating in the Uncompahgre Plateau collaborative forest restoration project in western Colorado, USA. Drawing on the concept of “positionality” in qualitative social science research, we disclose our respective motivations, assumptions, roles, and power relative to the collaborative process. The differences in evaluating collaborative progress stem from our respective professional positionality. For the academic, the guiding interest was to test theory and promote success for his applied research institute; for the practitioner, the motivation was to build trust to allow her field staff the flexibility to implement management actions and demonstrate effectiveness as an agency line officer. These epistemological differences draw attention to the importance of transdisciplinary approaches to producing knowledge from shared practice, starting with efforts to explicitly disclose and honor differing interests, assumptions, and frames of reference stemming from each party’s personal and professional biographies and institutional norms. This reflexivity is essential to advancing knowledge about collaboration in natural resource management. 相似文献
32.
The main removal mechanisms for the degradations of seven pollutants in wastewater treatment wetlands were analysed, and a mathematical model was established to quantify the removal of each pollutant, based on its main removal mechanisms. Subsurface horizontal flow wetlands were treated as a series of continuous stirred - tank reactors (CSTRs). Kinetic models for the removal of biochemical oxygen demand, chemical oxygen demand, ammonia, total nitrogen and faecal coliforms were established by combining Monod or first - order kinetics with CSTR assumptions. These tentative models account for a wide range of factors that affect wetland performance, but the models have not been proven by ex periment data. Depending on the derivation of various coefficients in the models and verification by actual performance data, this study may provide a starting point for an integrated pollutant removal model to be developed, and experimen tally verified, thereby making a step forward from the current greenbox' approach of wetland design. 相似文献
33.
34.
Prakash Mehra Michael N. Tsimplis R. G. Prabhudesai Antony Joseph Andrew G. P. Shaw Y. K. Somayajulu Paolo Cipollini 《Ocean Dynamics》2010,60(4):819-833
The contribution of atmospheric pressure and local wind to sea level variability at Goa (West coast of India) for the period
2007–2008 is investigated. Sea level data from a tide gauge are compared with measured local surface meteorological as well
as oceanographic data. Multilinear regression analysis is used to resolve the dependence of sea level on various forcing parameters.
The multilinear regression analysis performed over approx. 2-year data shows that the local surface meteorological data and
water temperature account for the sea level variability only up to 6%. The accounted sea level variability increases to 25%,
when the local wind and the surface currents obtained from satellite altimetry in the near vicinity of the study area are
incorporated in the regression analysis. The contribution of local wind increases substantially when the regression is performed
over a 2-month duration, and it is variable within the year. During the summer monsoon season (May–September), the sea level
variability attributable to wind is up to 47% and 75%, respectively, for 2007 and 2008; however, it reduces to <20% during
the winter monsoon (November–February) season. A significant part of the variability observed in sea level remains unaccounted
for and is attributed to remote forcing. 相似文献
35.
36.
S.A. Thorpe 《地球物理与天体物理流体动力学》2013,107(1):59-74
The effects of finite amplitude are examined in two-dimensional, standing, internal gravity waves in a rectangular container which rotates about a vertical axis at frequency f/ 2. Expressions are given for the velocity components, density fluctuations and isopycnal displacements to second order in the wave steepness in fluids with buoyancy frequency, N , of general form, and the effect of finite amplitude on wave frequency is given in an expansion to third order. The first order solutions, and the solutions to second order in the absence of rotation, are shown to conserve energy during a wave cycle. Analytical solutions are found to second order for the first two modes in a deep fluid with N proportional to sech( az ), where z is the upward vertical coordinate and a is scaling factor. In the absence of rotation, results for the first mode in the latter stratification are found to be consistent with those for interfacial waves. An analytical solution to fourth order in a fluid with constant N is given and used to examine the effects of rotation on the development of static instability or of conditions in which shear instability may occur. As in progressive internal waves, an effect of rotation is to enhance the possibility of shear instability for waves with frequencies close to f . The analysis points to a significant difference between the dynamics of standing waves in containers of limited size and progressive internal waves in an unlimited fluid; the effect of boundaries on standing waves may inhibit the onset of instability. A possible application of the analysis is to transverse oscillations in long, narrow, steep-sided lakes such as Loch Ness, Scotland. 相似文献
37.
Estimating the undiscovered mineral resources of a terrane is a challenging, yet essential, task in mineral exploration. We
apply Zipf’s law rank statistical analysis to estimate the undiscovered nickel sulphide resources in the Norseman-Wiluna Greenstone
Belt, Western Australia. The analysis suggests that about 3.0 to 10.0 Mt of nickel sulphide resources are yet to be discovered
in this belt, compared to the currently known total nickel sulphide endowment of 10.8 Mt. This undiscovered nickel sulphide
endowment is likely to be hosted by incompletely delineated deposits and undiscovered deposits in less explored komatiites
in the belt. Using the more detailed data subset of the Kambalda domain, this study manipulates Zipf’s law to estimate the
sizes of undiscovered deposits, in addition to the domain’s total nickel sulphide endowment estimate. Importantly, regression
analysis shows that the gradient of the line of best fit through the logarithmic rank-size plot for the detailed Kambalda
data subset is −1. This gradient, which is the key Zipf’s law constant k, has the value of −0.92 for the Norseman-Wiluna Greenstone Belt which is collectively less mature than the Kambalda domain.
This result corroborates the use of k = −1 in Zipf’s law predictive analyses of mineral resources for deposit populations for which the value of k = −1 has not yet been attained due to exploration immaturity. 相似文献
38.
This study investigates the mechanism of formation of convection plumes of mushroom shape in sub-solidus mantle and their prediction.The seismic-tomographic images of columnar structures of several hundreds kilometers in diameter have been reported by several researchers,while the much cherished mushroom-shaped plume heads could only be found in computational geodynamics(CGD) models and simple small-scale laboratory analogue simulations.Our theory of transient instability shows that the formation of conv... 相似文献
39.
The possible future impact of anthropogenic forcing upon the circulation of the Mediterranean, and the exchange through the
Strait of Gibraltar is investigated using a Cox-type model of the Mediterranean at 0.25° × 0.25° resolution, forced by “control”
and “greenhouse” scenarios provided by the HadCM2 coupled climate model. The current structure of the Mediterranean forced
by the “control” climate is compared with observations: certain aspects of the present circulation are reproduced, but others
are absent or incorrectly represented. Deficiencies are most probably due to weaknesses in the forcing climatology generated
by the climate model, so some caution must be exercised in interpreting the enhanced greenhouse simulation. Comparison of
the control and greenhouse scenarios suggests that deep-water production in the Mediterranean may be reduced or cease in the
relatively near future. The results also suggest that the Mediterranean outflow, may become warmer and more saline, but less
dense, and hence shallower. The volume of the exchange at the Strait of Gibraltar seems to be relatively insensitive to future
climate change, however. Our results indicate that a parameterisation of Gibraltar exchange and Mediterranean Outflow Water
(MOW) production may be able to provide adequate representation of the changes we observe for the purposes of the current
generation of climate models.
Received: 10 August 1998 / Accepted: 11 October 1999 相似文献
40.
Robert G. Scaife Antony J. Long Alistair J. Monteath Paul D. M. Hughes Michael J. Bentley Philip Stone 《第四纪科学杂志》2019,34(8):609-620
Oceanic island flora is vulnerable to future climate warming, which is likely to promote changes in vegetation composition, and invasion of non‐native species. Sub‐Antarctic islands are predicted to experience rapid warming during the next century; therefore, establishing trajectories of change in vegetation communities is essential for developing conservation strategies to preserve biological diversity. We present a Late‐glacial‐early Holocene (16 500–6450 cal a bp ) palaeoecological record from Hooker's Point, Falkland Islands (Islas Malvinas), South Atlantic. This period spans the Pleistocene‐Holocene transition, providing insight into biological responses to abrupt climate change. Pollen and plant macrofossil records appear insensitive to climatic cooling during the Late‐glacial, but undergo rapid turnover in response to regional warming. The absence of trees throughout the Late‐glacial‐early Holocene enables the recognition of far‐travelled pollen from southern South America. The first occurrence of Nothofagus (southern beech) may reflect changes in the strength and/or position of the Southern Westerly Wind Belt during the Late‐glacial period. Peat inception and accumulation at Hooker's Point is likely to be promoted by the recalcitrant litter of wind‐adapted flora. This recalcitrant litter helps to explain widespread peatland development in a comparatively dry environment, and suggests that wind‐adapted peatlands can remain carbon sinks even under low precipitation regimes. © 2019 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd. 相似文献