992 research outputs found
Modeling the Ecological Consequences of Visitor Behavior in Off-Trail Areas Dispersed Recreation Use
LAKE SHOREZONE FUNCTIONALITY INDEX (SFI) A tool for the definition of ecological quality as indicated by Directive 2000/60/CE
www.appa.provincia.tn.it/binary/pat_appa/pubblicazioni/IFP_Manual_english_ver2.1310115028.pd
LAKE SHOREZONE FUNCTIONALITY INDEX (SFI) A tool for the definition of ecological quality as indicated by Directive 2000/60/CE
www.appa.provincia.tn.it/binary/pat_appa/pubblicazioni/IFP_Manual_english_ver2.1310115028.pd
Numerical modeling of thermal bar and stratification pattern in Lake Ontario using the EFDC model
Thermal bar is an important phenomenon in large, temperate lakes like Lake
Ontario. Spring thermal bar formation reduces horizontal mixing, which in turn, inhibits the
exchange of nutrients. Evolution of the spring thermal bar through Lake Ontario is
simulated using the 3D hydrodynamic model Environmental Fluid Dynamics Code (EFDC).
The model is forced with the hourly meteorological data from weather stations around the
lake, flow data for Niagara and St. Lawrence rivers, and lake bathymetry. The simulation is
performed from April to July, 2011; on a 2-km grid. The numerical model has been
calibrated by specifying: appropriate initial temperature and solar radiation attenuation
coefficients. The existing evaporation algorithm in EFDC is updated to modified mass
transfer approach to ensure correct simulation of evaporation rate and latent heatflux.
Reasonable values for mixing coefficients are specified based on sensitivity analyses. The
model simulates overall surface temperature profiles well (RMSEs between 1-2°C). The
vertical temperature profiles during the lake mixed phase are captured well (RMSEs <
0.5°C), indicating that the model sufficiently replicates the thermal bar evolution process. An
update of vertical mixing coefficients is under investigation to improve the summer thermal
stratification pattern. Keywords: Hydrodynamics, Thermal BAR, Lake Ontario, GIS
Magnetoresistive biosensors with on-chip pulsed excitation and magnetic correlated double sampling.
Giant magnetoresistive (GMR) sensors have been shown to be among the most sensitive biosensors reported. While high-density and scalable sensor arrays are desirable for achieving multiplex detection, scalability remains challenging because of long data acquisition time using conventional readout methods. In this paper, we present a scalable magnetoresistive biosensor array with an on-chip magnetic field generator and a high-speed data acquisition method. The on-chip field generators enable magnetic correlated double sampling (MCDS) and global chopper stabilization to suppress 1/f noise and offset. A measurement with the proposed system takes only 20 ms, approximately 50× faster than conventional frequency domain analysis. A corresponding time domain temperature correction technique is also presented and shown to be able to remove temperature dependence from the measured signal without extra measurements or reference sensors. Measurements demonstrate detection of magnetic nanoparticles (MNPs) at a signal level as low as 6.92 ppm. The small form factor enables the proposed platform to be portable as well as having high sensitivity and rapid readout, desirable features for next generation diagnostic systems, especially in point-of-care (POC) settings
Local Passive Acoustic Monitoring of Narwhal Presence in the Canadian Arctic: A Pilot Project
Long-term community-based monitoring of narwhals (Monodon monoceros) is needed because narwhals are important to local Inuit and are facing changes in their environment. We examined the suitability of passive acoustic recording for monitoring narwhals, using data gathered in the Canadian Arctic from an autonomous acoustic recorder (Repulse Bay, 2006) and a hand-held digital recorder (Koluktoo Bay, 2006 – 08). We found a relationship between the number of narwhals observed passing a fixed point and the number of calls heard. In addition, we found that an automated call detector could isolate segments of recording containing narwhal vocalizations over long recording periods containing non-target sound, thus decreasing the time spent on the analysis. Collectively, these results suggest that combining passive acoustic sampling with an automated call detector offers a useful approach for local monitoring of the presence and relative abundance of narwhals.La nĂ©cessitĂ© d’avoir un programme communautaire de surveillance Ă long terme des narvals (Monodon monoceros) s’avère Ă©vidente Ă©tant donnĂ© que les narvals revĂŞtent de l’importance aux yeux des Inuits de la rĂ©gion et que leur environÂnement est en pleine Ă©volution. Nous explorons la pertinence d’un programme de surveillance par acoustique passive pour les populations de narvals Ă partir de donnĂ©es rĂ©coltĂ©es dans l’Arctique canadien Ă l’aide d’une enregistreuse autonome (Repulse Bay, 2006) et d’une enregistreuse portable (Koluktoo Bay, 2006 – 2008). Grâce Ă des enregistrements accompagnĂ©s d’obserÂvations sur le terrain, nous avons trouvĂ© une corrĂ©lation entre le nombre de vocalisations entendues et le nombre de narvals observĂ©s. L’utilisation d’un dĂ©tecteur automatique de vocalisations de narvals a permis d’isoler des segments d’enregisÂtrements contenant des vocalisations de narvals sur de longues pĂ©riodes d’enregistrement contenant des sons non-ciblĂ©s, et ainsi diminuer le temps d’analyse. Ces rĂ©sultats suggèrent que la combinaison de surveillance acoustique passive avec l’utiliÂsation d’un dĂ©tecteur automatique offre une approche utile pour la surveillance locale de la prĂ©sence et de l’abondance relative des narvals
Cost-Benefit Analysis in Planning Processes: An Interactive Instrument in an Integrated Approach
Increasing pressure on space demands careful assessment between competing functions in a planning process. Especially, in metropolitan landscapes, space is in short supply and hence expensive. Housing, industrial sites and office parks, and infrastructure are strong drivers of landscape change, often dominating nature and landscape which represent values with a more collective good character. Nevertheless, in The Netherlands, nature is becoming an important force in spatial planning. This assessment between competing functions, requires interactive planning and appropriate instruments. In the usual planning process, the costs and benefits of the development plans to society are only computed in the final stage of the process. We argue in this paper for integration of a social cost-benefit analysis (SCBA) in interactive regional planning processes. Firstly, it avoids time and money being spent on elaborating a plan, which is not beneficial to society. Secondly, it helps to prevent unwarranted enthusiasm for inauspicious plans among participants. From earlier studies, we learned that in the application of SCBA the discussion between researchers, clients and other participants should focus on two or three clearly distinctive models. Too much detail should be avoided. On the other hand, key indicators used in calculating effects have to be available and well documented. The summation of the costs and benefits provides a first impression of the financial and social feasibility of the plan. In a first planning session, therefore, a common understanding of the mechanisms underlying the assessment of the plan will be built up. This improves the support for SCBA of the final project. It also provides the stakeholders and shareholders with information about the feasibility of the plan at an early stage. Another advantage is that SCBA focuses on the benefits to society as a whole. Recently, we have spent much effort in the development of an interactive tool that is both relevant and user friendly. Relevant means that it takes into account the essential values of different types of land use and their interaction. At the moment we focus on spatial interaction and incorporating ecological network values. A prototype of the interactive integrated model is available for demonstration.
Spatial Analysis of Distributions and Habitat Conditions of Fallopia japonica (Japanese Knotweed) Invasive Species Applying Unmanned Helicopter Remote Sensing
Abstract:
Fallopia japonica (Japanese knotweed) is a perennial herbaceous plant that is native to East Asia. It is considered as one of the worst invasive species worldwide because of its serious impact on biological diversity and human activities (Lowe et al., 2001). Once established, Japanese knotweed forms dense stands that shade and crowd out native plant species. The objectives of this research were to verify and confirm the distribution of Japanese knotweed as published online by the New York Department of Environmental Conservation (DEC) – iMap and to identify the geographic areas of spreading and the local habitat conditions. In this research, we apply an unmanned helicopter with multiple sensors including digital camera, thermometer and relative humidity sensor to survey the patches of F.japonica and its three-dimensional (3D) habitat conditions. The areas of each of the patch surveyed were identified and delineated in polygons applying ERDAS Imagine and ArcGIS software. To identify the local habitat conditions, the shade cover and distance to nearest water body were analyzed by using traditional statistical methods. And the distributions of temperature and relative humidity were analyzed in three-dimensional (3D) method in GIS environment
Celebrating 25 Years of World Wetlands Day
The purpose of this Special Issue is to celebrate 25 years of “World Wetlands Day”. There is no other ecosystem that has its very own Ramsar Convention or such a challenge impacting ecosystem sustainability. Papers for this Special Issue provide an overview of wetland status and function within different regions of the world. The papers in this Special Issue of Land consist of three review papers, ten research articles and one perspective paper. Edward Maltby’s review paper provides us with an overview of the paradigm shift of how we value and assess wetlands over time. Ballut-Dajud et al. provide us with a worldwide perspective on factors affecting wetland loss. Finally, Jan Vymazal provides us with a historical overview of the development of water quality treatment wetlands in Europe and North America. The research papers can be grouped into four groups: 1) use of remote sensing to analyze stability and dynamic factors affecting wetlands; 2) factors affecting the wetlands’ ability to store carbon; 3) assessment of wetlands effect on water quality; and 4) understanding historical use and value of wetlands, farmer’s attitudes about wetland management, and how we can value wetland ecosystem services. Finally, Bryzek et al. remind us that, as wetland researchers and managers, we should minimize damage to wetlands even through field monitoring work
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