scholarly journals Associations between the Ecology of Virulent Rhodococcus equi and the Epidemiology of R. equi Pneumonia on Australian Thoroughbred Farms

2006 ◽  
Vol 72 (9) ◽  
pp. 6152-6160 ◽  
Author(s):  
G. Muscatello ◽  
G. A. Anderson ◽  
J. R. Gilkerson ◽  
G. F. Browning
Keyword(s):  
Model Building ◽  
Management Strategies ◽  
Rhodococcus Equi ◽  
Soil Conditions ◽  
Virulent Strains ◽  
Environmental Management Strategies ◽  
Horse Farms ◽  
Breeding Farms ◽  
Breeding Seasons ◽  
The Impact

ABSTRACT The ecology of virulent strains of Rhodococcus equi on horse farms is likely to influence the prevalence and severity of R. equi pneumonia in foals. This study examined the association between the ecology of virulent R. equi and the epidemiology of R. equi pneumonia by collecting air and soil samples over two breeding seasons (28 farm-year combinations) on Thoroughbred breeding farms with different reported prevalences of R. equi pneumonia. Colony blotting and DNA hybridization were used to detect and measure concentrations of virulent R. equi. The prevalence of R. equi pneumonia was associated with the airborne burden of virulent R. equi (both the concentration and the proportion of R. equi bacteria that were virulent) but was not associated with the burden of virulent R. equi in the soil. Univariable screening and multivariable model building were used to evaluate the effect of environmental and management factors on virulent R. equi burdens. Lower soil moisture concentrations and lower pasture heights were significantly associated with elevated airborne concentrations of virulent R. equi, as were the holding pens and lanes, which typically were sandy, dry, and devoid of pasture cover. Few variables appeared to influence concentrations of virulent R. equi in soil. Acidic soil conditions may have contributed to an elevated proportion of virulent strains within the R. equi population. Environmental management strategies that aim to reduce the level of exposure of susceptible foals to airborne virulent R. equi are most likely to reduce the impact of R. equi pneumonia on endemically affected farms.

scholarly journals Use of a mathematical model to estimate the impact of shrimp pen culture at Patos Lagoon estuary, Brazil

2014 ◽  
Vol 86 (3) ◽  
pp. 1063-1076 ◽  
Author(s):  
LUÍS H. POERSCH ◽  
ÂNGELA M. MILACH ◽  
RONALDO O. CAVALLI ◽  
WILSON JR. WASIELESKY ◽  
OSMAR MÖLLER ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Management Strategies ◽  
Water Current ◽  
Patos Lagoon ◽  
Water Current Velocity ◽  
Environmental Management Strategies ◽  
Farfantepenaeus Paulensis ◽  
Nitrogen Concentrations ◽  
Definition Of ◽  
The Impact

Ecological modeling has been used as a tool to estimate potential impacts caused by aquaculture to the surrounding environment. In this work, a mathematical model was applied to estimate the maximum amount of pink shrimp (Farfantepenaeus paulensis) culture units (3,100m2 pen enclosures) that could be installed at two shallow estuarine bays of Patos Lagoon (known as Coreia and Porto do Rei) with no significant effects on either water quality or viability of the culture system. To calibrate the model, information about the culture of Litopenaeus vannamei and F. paulensis as well as field data (influence of netting material, water current speed and nitrogen concentrations) were used. Under a bad scenario (water current velocity of 0.01m s–1 and a mesh clogging effect of 40%), it would be possible to install up to 29 pens at the Coreia bay, and 39 pens at the Porto do Rei bay. Results indicate that the model was useful in determining the maximum number of culture units that could be installed at these bays, and thus have the potential to become an important tool in the definition of environmental management strategies in relation to aquaculture development.

scholarly journals Back to the Wild: Polluted Site Remediation and Biosphere Resilience

2021 ◽  
Author(s):  
Débora Toledo Ramos ◽  
Henry Xavier Corseuil ◽  
Timothy M. Vogel
Keyword(s):  
Anthropogenic Impacts ◽  
Management Strategies ◽  
Microbial Composition ◽  
Disturbed Condition ◽  
Regulatory Processes ◽  
Environmental Management Strategies ◽  
Pollution Event ◽  
Local Ecosystem ◽  
The Impact ◽  
Pollution Events

ABSTRACTWorldwide efforts to depollute environments altered by human industrial activity have begun to produce an ever-increasing number of “clean” sites. “Clean” is defined by local regulatory processes and often responds to low compound concentrations or risk evaluations. Yet, these sites have been critically derailed from their historical biological activity by both the pollution event and the clean-up technology. This work explored the impact of contaminated (and remediated) sites on local microbial ecosystems. Different parcels of the same field site with the same relatively uniform microbial ecology were polluted and cleaned-up over the last 15 years. The statistical evaluation of the perturbation described changes to the local ecosystem that went back to the original baseline microbial composition although the pollution sources and the clean-up technologies affected the rate of return to the pre-disturbed condition. This rate reflected the intensity of the clean-up treatments. The role played by microbial communities on ecosystem maintenance and mitigation of pollution events lays the groundwork for predicting the microbial community responses to perturbations and the ability to reassert themselves. Predictions of ecosystem response to anthropogenic impacts could support decision-making on environmental management strategies for contaminated sites clean-up, depending on the ecosystem services desired to maintain or the risk posed to sensitive receptors.

The methodological approach for the determination of the pressure of artificial raindrops as a question of the theory of splash soil erosion

2020 ◽  
pp. 24-28
Author(s):  
Mihail Zver'kov
Keyword(s):  
Block Diagram ◽  
Methodological Approach ◽  
Control Measures ◽  
Soil Conditions ◽  
Effective Pressure ◽  
Long Distance ◽  
Splash Erosion ◽  
Rain Drops ◽  
Artificial Rain ◽  
The Impact

To the article the results of the theoretical and experimental researches are given on questions of estimates of the dynamic rate effect of raindrop impact on soil. The aim of this work was to analyze the current methods to determine the rate of artificial rain pressure on the soil for the assessment of splash erosion. There are the developed author’s method for calculation the pressure of artificial rain on the soil and the assessment of splash erosion. The study aims to the justification of evaluation methods and the obtaining of quantitative characteristics, prevention and elimination of accelerated (anthropogenic) erosion, the creation and the realization of the required erosion control measures. The paper considers the question of determining the pressure of artificial rain on the soil. At the moment of raindrops impact, there is the tension in the soil, which is called vertical effective pressure. It is noted that the impact of rain drops in the soil there are stresses called vertical effective pressure. The equation for calculation of vertical effective pressure is proposed in this study using the known spectrum of raindrops. Effective pressure was 1.4 Pa for the artificial rain by sprinkler machine «Fregat» and 5.9 Pa for long distance sprinkler DD-30. The article deals with a block diagram of the sequence for determining the effective pressure of rain drops on the soil. This diagram was created by the author’s method of calculation of the effective pressure of rain drops on the soil. The need for an integrated approach to the description of the artificial rain impact on the soil is noted. Various parameters characterizing drop erosion are considered. There are data about the mass of splashed soil in the irrigation of various irrigation machinery and installations. For example, the rate (mass) of splashed soil was 0.28…0.78 t/ha under irrigation sprinkler apparatus RACO 4260–55/701C in the conditions of the Ryazan region. The method allows examining the environmental impact of sprinkler techniques for analyzes of the pressure, caused by raindrops, on the soil. It can also be useful in determining the irrigation rate before the runoff for different types of sprinkler equipment and soil conditions.

scholarly journals Immunization Strategies for Funding Multiple Inflation-Linked Retirement Income Benefits

Risks ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 60
Author(s):  
Cláudia Simões ◽  
Luís Oliveira ◽  
Jorge M. Bravo
Keyword(s):  
Interest Rate ◽  
Yield Curve ◽  
Risk Measure ◽  
Management Strategies ◽  
Interest Rate Risk ◽  
Insurance Companies ◽  
Retirement Income ◽  
Investment Strategies ◽  
Immunization Strategies ◽  
The Impact

Protecting against unexpected yield curve, inflation, and longevity shifts are some of the most critical issues institutional and private investors must solve when managing post-retirement income benefits. This paper empirically investigates the performance of alternative immunization strategies for funding targeted multiple liabilities that are fixed in timing but random in size (inflation-linked), i.e., that change stochastically according to consumer price or wage level indexes. The immunization procedure is based on a targeted minimax strategy considering the M-Absolute as the interest rate risk measure. We investigate to what extent the inflation-hedging properties of ILBs in asset liability management strategies targeted to immunize multiple liabilities of random size are superior to that of nominal bonds. We use two alternative datasets comprising daily closing prices for U.S. Treasuries and U.S. inflation-linked bonds from 2000 to 2018. The immunization performance is tested over 3-year and 5-year investment horizons, uses real and not simulated bond data and takes into consideration the impact of transaction costs in the performance of immunization strategies and in the selection of optimal investment strategies. The results show that the multiple liability immunization strategy using inflation-linked bonds outperforms the equivalent strategy using nominal bonds and is robust even in a nearly zero interest rate scenario. These results have important implications in the design and structuring of ALM liability-driven investment strategies, particularly for retirement income providers such as pension schemes or life insurance companies.

scholarly journals Understanding the Impact of Different Landscape-Level Fuel Management Strategies on Wildfire Hazard in Central Portugal

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 522
Author(s):  
Akli Benali ◽  
Ana C. L. Sá ◽  
João Pinho ◽  
Paulo M. Fernandes ◽  
José M. C. Pereira
Keyword(s):  
Management Strategies ◽  
Treatment Strategies ◽  
Fire Season ◽  
Burned Area ◽  
Treatment Area ◽  
Fuel Treatment ◽  
The North ◽  
Wildfire Hazard ◽  
Central Portugal ◽  
The Impact

The extreme 2017 fire season in Portugal led to widespread recognition of the need for a paradigm shift in forest and wildfire management. We focused our study on Alvares, a parish in central Portugal located in a fire-prone area, which had 60% of its area burned in 2017. We evaluated how different fuel treatment strategies may reduce wildfire hazard in Alvares through (i) a fuel break network with different extents corresponding to different levels of priority and (ii) random fuel treatments resulting from a potential increase in stand-level management intensity. To assess this, we developed a stochastic wildfire simulation system (FUNC-SIM) that integrates uncertainties in fuel distribution over the landscape. If the landscape remains unchanged, Alvares will have large burn probabilities in the north, northeast and center-east areas of the parish that are very often associated with high fireline intensities. The different fuel treatment scenarios decreased burned area between 12.1–31.2%, resulting from 1–4.6% increases in the annual treatment area and reduced the likelihood of wildfires larger than 5000 ha by 10–40%. On average, simulated burned area decreased 0.22% per each ha treated, and cost-effectiveness decreased with increasing area treated. Overall, both fuel treatment strategies effectively reduced wildfire hazard and should be part of a larger, holistic and integrated plan to reduce the vulnerability of the Alvares parish to wildfires.

scholarly journals Rural Roads Are Paving the Way for Land-Use Intensification in the Uplands of Laos

Land ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 330
Author(s):  
Jean-Christophe Castella ◽  
Sonnasack Phaipasith
Keyword(s):  
Land Use ◽  
Management Practices ◽  
Management Strategies ◽  
Farming Systems ◽  
Long Term Effects ◽  
Group Discussions ◽  
Rural Roads ◽  
External Resources ◽  
Hybrid Maize ◽  
The Impact

Road expansion has played a prominent role in the agrarian transition that marked the integration of swidden-based farming systems into the market economy in Southeast Asia. Rural roads deeply altered the landscape and livelihood structures by allowing the penetration of boom crops such as hybrid maize in remote territories. In this article, we investigate the impact of rural road developments on livelihoods in northern Laos through a longitudinal study conducted over a period of 15 years in a forest frontier. We studied adaptive management strategies of local stakeholders through the combination of individual surveys, focus group discussions, participatory mapping and remote-sensing approaches. The study revealed the short-term benefits of the maize feeder roads on poverty alleviation and rural development, but also the negative long-term effects on agroecosystem health and agricultural productivity related to unsustainable land use. Lessons learnt about the mechanisms of agricultural intensification helped understanding the constraints faced by external interventions promoting sustainable land management practices. When negotiated by local communities for their own interest, roads may provide livelihood-enhancing opportunities through access to external resources, rather than undermining them.

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