An Overview of Aridland Ciénagas, With Proposals for Their Classification, Restoration and Preservation

Ciénagas are the American Southwest’s most unusual wetlands, yet they are dwindling. This paper addresses what they are, their uniqueness and importance, how they developed, and the causes for the loss of most ciénaga habitat. We also propose a classification system for ciénagas that will contribute to a more meaningful and better-focused discussion about ciénagas, provide an inventory of known ciénagas, and suggest a system of Ciénaga Coordinators with the goal of identifying, restoring, and preserving the few remaining ciénagas. Finally, the inventory from this paper is made available online in an interactive, open, moderated format that will allow anyone to contribute to the correction, evolution, and general improvement and growth of this database, and to download and use the content. A link to this system can be found in a permanent archive of this paper at http://hdl.handle.net/2152/30285. The data from Appendix B of the paper archived here later prompted formation of the the North American Ciénegas Project (https://www.google.com/fusiontables/DataSource?docid=1n9Z5nJ7BXY0TLBbGjFYzFcRooMWCWK_AQDQVAV24), which hopes to involve a broad community of interested individuals and citizen scientists in further improving and increasing openly shared information about all aridland ciénegas of western North America.Integrative Biolog

Analysis of magnetohydrodynamics effects on convective flow of dusty viscous fluid

This paper presents a finite difference analysis of Magnetohydrodynamics (MHD) effects on convective flow of dusty viscous fluid  incorporating viscous dissipation with respect to fluid and dusty particle. The criterion for the existence and unique solution is established  and the properties of solution are examined. The dimensionless governing coupled non-linear partial differential equations governing the phenomenon were solved numerically using finite difference scheme. The effects of various parameters on the velocities are shown graphically and discussed. It is observed that both the velocity of the fluid φ and dust particles χ increases with an increase in Grashof number. Velocity of the fluid decreases with an increase in Magnetic parameter. Increase in Porosity parameter has little effects on the velocity of the fluid and that of the particle. Slight increase in volume faction of dust particles increases the velocity of the particles rapidly and increases moderately the velocity of the fluid. Increase in Mass concentration of dust particles decreases the velocity of both the fluid and particles. Also, considerable effect was noticed on the temperature ϑ by increasing the Eckert number, temperature also increased. Increase in the Prandtl number decreases the temperature of the fluid

Analytical simulation of two dimensional advection dispersion equation of contaminant transport

The study was designed to investigate the analytical simulation of two dimensional advection dispersion equation of contaminant transport. The steady state flow condition of the contaminant transport where inorganic contaminants in aqueous waste solutions are disposed of at the land surface where it would migrate through the verdoze zone to underground water is considered. We solved the two dimensional advection dispersion equation analytically which is solute transport model without sorption or degradation using change of variable method. We critically reviewed two dimensional equations depicting the transport of contaminant in groundwater and investigate with the help of graphical representation the effect of Peclet number on the concentration of contaminant and established real life interpretation of contaminant transport. Two cases were considered, when Peclet number is less than one and when Peclet number is greater than one. The result obtained revealed that the contaminant concentration increases along x direction and decreases along y direction for both values of peclet number greater than one and less than one. The study has contributed to knowledge through the method utilized to achieve the model analytical solution and the Physical interpretation of Peclet number. From the analysis, we recommend for further studies on the contaminant transport which also depends on the available data, that the extension of advection –dispersion model to three dimensions and comparison of travel time of contaminant transport solution to Kinetic or multi-component mode.Keywords: Contaminant, Seepage Velocity, Aquifer, Advection-dispersion Equation, change of variable method

Formulation of a mathematical model for the analysis of the emission of carbon dioxide from gaseous fuel using least square method

In this paper we formulate a model for the emission of Carbon Dioxide from gaseous fuel in Nigeria. We considered a third degree polynomial model using a least square method using the actual data set of twenty one years on State level Carbon Dioxide emissions in Nigeria from 1994-2014. The residual analysis was used to predict the short and medium term total Carbon Dioxide emissions trend. From the results the state of affairs of Carbon Dioxide Emission for subsequent years was forecast and this will help the Government to take control measures in curtailing the emission of Carbon Dioxide in the country.Keywords: Gaseous fuel, Automobile, Fossil fuels, Pollutants, Carbon Dioxide, Emission

Modeling and analytical simulation of high-temperature gas filtration combustion

High temperature filtration in combustion and gasification processes is a highly interdisciplinary field. Thus, particle technology in general has to be supported by elements of physics, chemistry, thermodynamics and heat and mass transfer processes. Presented in this paper is the analytical method for describing hightemperature gas filtration combustion in an inert porous medium. We assume the porous media is highly permeable and both the contact time between the phases and the rate of oxidizer diffusion through the gas stream to the surface of the solid particles where the reaction occurs are not large. Also, we assume that the initial temperatures increase lengthwise. The coupled nonlinear partial differential equations describing the phenomenon have been decoupled using the parameter-expanding method and solved analytically using eigenfunctions expansion technique. The results obtained revealed that the combustion wave is propagated and oxidizer is consumed. A self-oscillating mode of gas filtration combustion was found with variation in the values of interfacial heat transfer.Keywords: Analytical method, filtration combustion, fuel, oxidizer, porous medium, temperatur

Modeling and analytical simulation of anterior polymerization in the presence of an inert material

The ability to fabricate advanced materials with specific properties efficiently requires a complete understanding of the polymerization kinetics and the effect of several preparative variables such as temperature, monomer and initiator. This paper presents an analytical method for describing anterior polymerization in two adjacent thin layers. Both the initial temperatures and initial monomer and initiator concentrations are assumed to depend on the space variable. We prove the existence and uniqueness of solution of the model by actual solution method. The equations are solved using parameter-expanding method and eigenfunctions expansion technique. The results obtained were discussed. The study shows that the Frank-Kamenetskii number and frequency factors of the two reactions have significant effects on the propagation of the polymerization wave.Keywords: Polymerization, anterior polymerization, polymers, Arrhenius kinetics, parameter-expanding method, eigenfunctions expansion techniqu

Distinctive impact craters are formed by organic rich cometary dust grains

Introduction: Preliminary Examination (PE) of the Stardust cometary collector revealed many tracks in the silica aerogel and impact craters on aluminium (Al) foil, from which Wild 2 dust particle fluence and size distribution were determined. Laboratory light gas gun (LGG) shots provided impactor size calibrations. Analogue impacts of diverse mineral compositions and aggregate particles aided interpretation of dust composition and structure. We now describe our recent impact experiments on foil by organic materials, which reveal distinctive crater surface textures, and even preserved residue

Microcraters in aluminum foils exposed by Stardust

We will present preliminary results on the nature and size frequency distribution of microcraters that formed in aluminum foils during the flyby of comet Wild 2 by the Stardust spacecraft

Auditory network connectivity in tinnitus patients: a resting-state fMRI study

Objective: Resting-state functional magnetic resonance imaging (fMRI) uncovers correlated activity between spatially distinct functionally related brain regions and offers clues about the integrity of functional brain circuits in people with chronic subjective tinnitus. We chose to investigate auditory network connectivity, adopting and extending previously used analyses methods to provide an independent evaluation of replicability. Design: Independent components analysis (ICA) was used to identify coherent patterns arising from spontaneous brain signals within the resting-state data. The auditory network component was extracted and evaluated. Bivariate and partial correlation analyses were performed on pre-defined regions of bilateral auditory cortex to assess functional connectivity. Study sample: Our design carefully matched participant groups for possible confounds, such as hearing status. Twelve patients (seven male, five female; mean age 66 years) all with chronic constant tinnitus and eleven controls (eight male, three female; mean age 68 years) took part. Results: No significant differences were found in auditory network connectivity between groups after correcting for multiple statistical comparisons in the analysis. This contradicts previous findings reporting reduced auditory network connectivity; albeit at a less stringent statistical threshold. Conclusions: Auditory network connectivity does not appear to be reliably altered by the experience of chronic subjective tinnitus

Walking, Gross Motor Development, and Brain Functional Connectivity in Infants and Toddlers

Infant gross motor development is vital to adaptive function and predictive of both cognitive outcomes and neurodevelopmental disorders. However, little is known about neural systems underlying the emergence of walking and general gross motor abilities. Using resting state fcMRI, we identified functional brain networks associated with walking and gross motor scores in a mixed cross-sectional and longitudinal cohort of infants at high and low risk for autism spectrum disorder, who represent a dimensionally distributed range of motor function. At age 12 months, functional connectivity of motor and default mode networks was correlated with walking, whereas dorsal attention and posterior cingulo-opercular networks were implicated at age 24 months. Analyses of general gross motor function also revealed involvement of motor and default mode networks at 12 and 24 months, with dorsal attention, cingulo-opercular, frontoparietal, and subcortical networks additionally implicated at 24 months. These findings suggest that changes in network-level brain-behavior relationships underlie the emergence and consolidation of walking and gross motor abilities in the toddler period. This initial description of network substrates of early gross motor development may inform hypotheses regarding neural systems contributing to typical and atypical motor outcomes, as well as neurodevelopmental disorders associated with motor dysfunction