593 research outputs found
A Discrete Age Structured Model of Hantavirus in a Rodent Reservoir in Paraguay
Many rodent-borne hantaviruses are zoonotic pathogens that can cause disease in humans through inhalation of aerosolized rodent excreta. To evaluate the prevalence of JaborĂą virus (JABV) over time within its rodent reservoir, Akodon montensis, we formulated a mathematical model with multiple rodent age classes and unique infection class progression features. We then parameterized the model with data collected from a survey of JABV harbored by Akodon montensis in the MbaracayĂș Reserve in Paraguay. Our model incorporates three types of infection over the lifetime of the rodent as well as a recovered class. A new feature of the model allows transition from the latent to the persistently-infected class. With a more complete age and infection structure, we are better able to identify the driving forces of epidemiology of hantaviruses in rodent populations
The Missing Metric: An Evaluation of Fungal Importance in Wetland Assessments
To preserve wetland ecosystem function, federal and state agencies have developed assessment procedures to better manage remaining wetland areas. Currently, wetland assessments do not consider microorganisms when determining wetland quality. This is notable, because fungi are often the primary decomposers of organic material and thus important players in nutrient cycling. The objective of this study is to quantify how wetland quality, as measured using the Ohio Rapid Assessment Method (ORAM), relates to fungal community composition. We sampled soils from six depressional emergent marshes in Ohio belonging to each of the three ORAM quality categories, assessed soil physicochemical properties, and recovered fungal DNA. We then determined if wetland quality as expressed by the ORAM reflects soil health. Our results indicate that ORAM scoring methodology significantly explains differences in fungal community composition between wetlands. We also found that soil physicochemical properties not currently included in the ORAM are strong drivers of fungal community composition, particularly bulk density, pH, soil organic matter, and soil moisture. Overall, our results suggest fungal community composition reflects wetland quality as assessed by the ORAM, and that the ORAM and potentially other wetland assessments could better capture the soil environment by including easily measured soil physicochemical properties
Dredged Sediments Contain Potentially Beneficial Microorganisms for Agriculture and Little Harmful Cyanobacteria
Abstract Introduction Soils worldwide are degrading, raising concerns about our ability to feed the growing global population. Soil amendments that can alleviate degradation are gaining attention. The application of sediments dredged from waterways to agricultural fields has increasing promise as a means for improving degraded soils. However, herbaceous plant species may have difficulty establishing on dredged material because of low nutrient availability, inhibitory levels of toxins, unsuitable moisture conditions and lack of microorganisms capable of ameliorating these characteristics. To counteract these issues, we sought to understand if the use of a cover crop would increase the abundance, diversity and function of beneficial soil microorganisms compared to harmful microorganisms in dredged sediments. Materials and Methods We collected soil samples from two 100% dredged sediment plots, one where winter cereal rye (Secale cereal) was grown as a winter cover crop and one left fallow over the winter, followed by traditional corn (Zea mays) planting. We sampled both plots three times during the growing season: before cover crop application, following cover crop application but before corn planting and following final corn harvest. We then used highâthroughput sequencing to identify the bacterial and fungal communities present in the samples. Results Our data show that cover crop application did not alter the microbial community in these plots. However, sampling time decreased species diversity and altered the composition of both fungal and bacterial communities recovered from these plots. Across both plots, microorganisms associated with carbon cycling were more abundant than those associated with harmful effects, including microcystinâproducing cyanobacteria, which were an extremely small portion of the overall community. Conclusion Our work suggests that dredged sediments have the potential to improve soil function through the addition of microorganisms associated with nutrient cycling, but a cover crop is not necessary to incur these benefits
Frictionless Authentication Systems: Emerging Trends, Research Challenges and Opportunities
Authentication and authorization are critical security layers to protect a
wide range of online systems, services and content. However, the increased
prevalence of wearable and mobile devices, the expectations of a frictionless
experience and the diverse user environments will challenge the way users are
authenticated. Consumers demand secure and privacy-aware access from any
device, whenever and wherever they are, without any obstacles. This paper
reviews emerging trends and challenges with frictionless authentication systems
and identifies opportunities for further research related to the enrollment of
users, the usability of authentication schemes, as well as security and privacy
trade-offs of mobile and wearable continuous authentication systems.Comment: published at the 11th International Conference on Emerging Security
Information, Systems and Technologies (SECURWARE 2017
Closed-Loop Two-Stage Stochastic Optimization of Offshore Wind Farm Collection System
A two-stage stochastic optimization model for the design of the closed-loop
cable layout of an Offshore Wind Farm (OWF) is presented. The model consists on
a Mixed Integer Linear Program (MILP) with scenario numeration incorporation to
account for both wind power and cable failure stochasticity. The objective
function supports simultaneous optimization of: (i) Initial investment (network
topology and cable sizing), (ii) Total electrical power losses costs, and (iii)
Reliability costs due to energy curtailment from cables failures. The
mathematical optimization program is embedded in an iterative framework called
PCI (Progressive Contingency Incorporation), in order to simplify the full
problem while still including its global optimum. The applicability of the
method is demonstrated by tackling a real-world instance. Results show the
functionality of the tool in quantifying the economic profitability when
applying stochastic optimization compared to a deterministic approach, given
certain values of failure parameters
Creating functional nanostructures: Encapsulation of caffeine into α-lactalbumin nanotubes
This work evaluated the stability and functionality of nanotubes obtained from α-lactalbumin (α-LA). α-LA nanotubes' structure was highly stable during a freeze-drying process but not after grinding. The ability of α-LA nanotubes to encapsulate caffeine, used as a model molecule, was evaluated. α-La nanotubes were highly effective for this purpose as encapsulation efficiency (%EE) was near 100% and loading capacity (%LC) near 10% at 1.5/20 and 2/20 ratios (caffeine/α-LA, w/w). α-LA nanotubes' structure was not affected by the presence of caffeine. Also, in general, refrigeration temperatures and neutral or alkaline conditions, under which the adverse effect of chelating agents was prevented, helped to stabilise α-LA nanotubes' structure and maintain caffeine encapsulated. At 8 °C and pH 7.5, in the presence of 75 ÎŒg mLâ 1 of EDTA, > 50% of the caffeine remained encapsulated into α-LA nanotubes.Clara Fuciños gratefully acknowledge her Post-Doctoral grant (I2C 2014) from ConsellerĂa de Cultura, EducaciĂłn e OrdenaciĂłn Universitaria (Xunta de Galicia, Spain). Pablo Fuciños gratefully acknowledges his Marie Curie COFUND Postdoctoral Research Fellowship (Project No: 600375. NanoTRAINforGrowth - INL Fellowship programme in nanotechnologies for biomedical, environment and food applications). This study was supported by the Fundação para a CiĂȘncia e a Tecnologia (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684), and the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462)
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