Rural change and multidimensional analysis of farm’s vulnerability: a case study in a protected area of semi-arid northern Nicaragua

This paper presents an empirical research in a protected area of northern Nicaragua, aimed at: (a) classifying predominant narratives surrounding present and future pathways of the local rural system, drivers of change, features of livelihoods’ vulnerability; (b) understanding current functioning of local metabolic patterns of rural systems by developing a typology of farms and (c) comparing types’ vulnerability to current drivers of change. To achieve these objectives, we integrated qualitative and quantitative analytical approaches. The different visions of rural spaces, which emerge from the analysis of the narratives, and the five types of farms, characterized by specific land-time budget and energy and monetary flows, suggest two emerging dynamics of local restructuration in protected areas: (1) a dominant land re-concentration process which is generating increasing inequality in access to resources and a progressive marginalization of the self-sufficient economy of landless and subsistence households; (2) an emergence of a paradigm of ‘environmentalization’ of rural spaces together with a valorization of small and medium-scale diversified economies. Moreover, the vulnerability assessment focuses on multidimensional features of types’ sensitivity to crisis, i.e. risk unacceptability, production instability, economic inefficiency, food and exosomatic energy dependency, as well as capacity to buffer and adapt to change, i.e. access to assets, including labour for men and women, social safety nets and degrees of economic diversification. The discussion highlights the occurrence of trade-off between the solutions adopted by farms within different development paths, suggesting the relevance of the proposed framework of analysis at the interface between science and policy.     

QSAR trout toxicity models on aromatic pesticides

The pesticides originally designed to kill target organisms are dangerous for many other wild species. Since they are applied directly to the environment, they can easily reach the water basins and the topsoil. A dataset of 125 aromatic pesticides with well-expressed aquatic toxicity towards trout was subjected to quantitative structure activity relationships (QSAR) analysis aimed to establish the relationship between their molecular structure and biological activity. A literature data for LC50 concentration killing 50% of fish was used. In addition to the standard 2D-QSAR analysis, a comparative molecular field analysis (CoMFA) analysis considering the electrostatic and steric properties of the molecules was also performed. The CoMFA analysis helped the recognition of the steric interactions as playing an important role for aquatic toxicity. In addition, the transport properties and the stability of the compounds studied were also identified as important for their biological activity.     

Stormwater treatment: examples of computational fluid dynamics modeling

Control of rainfall-runoff particulate matter (PM) and PM-bound chemical loads is challenging; in part due to the wide gradation of PM complex geometries of many unit operations and variable flow rates. Such challenges and the expense associated with resolving such challenges have led to the relatively common examination of a spectrum of unit operations and processes. This study applies the principles of computational fluid dynamics (CFD) to predict the particle and pollutant clarification behavior of these systems subject to dilute multiphase flows, typical of rainfall-runoff, within computationally reasonable limits, to a scientifically acceptable degree of accuracy. The Navier-Stokes (NS) system of nonlinear partial differential equations for multiphase hydrodynamics and separation of entrained particles are solved numerically over the unit operation control volume with the boundary and initial conditions defined and then solved numerically until the desired convergence criteria are met. Flow rates examined are scaled based on sizing of common unit operations such as hydrodynamic separators (HS), wet basins, or filters, and are examined from 1 to 100 percent of the system maximum hydraulic operating flow rate. A standard turbulence model is used to resolve flow, and a discrete phase model (DPM) is utilized to examine the particle clarification response. CFD results closely follow physical model results across the entire range of flow rates. Post-processing the CFD predictions provides an in-depth insight into the mechanistic behavior of unit operations by means of three dimensional (3-D) hydraulic profiles and particle trajectories. Results demonstrate the role of scour in the rapid degradation of unit operations that are not maintained. Comparisons are provided between measured and CFD modeled results and a mass balance error is identified. CFD is arguably the most powerful tool available for our profession since continuous simulation modeling.     

Effects of Motorized Tourboats on the Behavior of Nonbreeding American Flamingos in Yucatan, Mexico

We assessed the effect of motorized tourboats on the behavior of nonbreeding American flamingos (  Phoenicopterus ruber ruber) in the Celestún Estuary, a Special Biosphere Reserve in Yucatán, Mexico, from November 1994 through February 1995. We measured these effects by comparing activity budgets between flocks of flamingos disturbed and undisturbed by tourboats. Disturbance reduced feeding time from 40% before disturbance to 24% after, a 40% loss. Boat disturbance increased alert behavior by 400%. Tourboats averaged 13 per day and caused a disturbance 75% of the time or 3.3 hours per day. Potential loss of feeding time for individuals was estimated at 13% but is likely much higher on days with excessive numbers of tourboats. Flamingos returned to normal feeding rates (40%) within 20 minutes after disturbance. Most tourists (52%) were from Mexico, followed by Germany (14%), and 88% of Mexican visitors were willing to pay an entrance fee to the Celestún Reserve. Conservation efforts should focus on education of tourboat operators to reduce disturbance to flamingos, education of tourists through a visitor's center and brochures produced in Spanish and English, and expanded involvement of local people.     

Sustainability and New Models of Consumption: The Solidarity Purchasing Groups in Sicily

European society, with its steadily increasing welfare levels, is not only concerned with food (safety, prices), but also with other aspects such as biodiversity loss, landscape degradation, and pollution of water, soil, and atmosphere. To a great extent these concerns can be translated into a larger concept named sustainable development, which can be defined as a normative concept by). Sustainability in the food chain means creating a new sustainable agro-food system while taking the institutional element into account. While different concepts of sustainability abound, in recent years, spontaneous groups of consumers called solidarity purchase groups (SPG) have been developing. In short, they are characterized by an economy that is not necessarily local, but ethical and equitable, where social and economic territorial relations tend to develop districts and networks. One of the main characteristics of a SPG is the direct relationships between small farms and their customers; a relationship that is characterized by consumer participation and farmer specialization. This study aims to address issues related to organizational frameworks, at farm and chain level, and to assess those elements that lead to consumer choice and satisfaction.