Juan Pedro Flores-Margez

Mapping of Airborne Particulate Matter Collected Using Two Sensors along US-Mexico Border

Particulate matter (PM) emissions from various sources can have significant effect on human health and environmental quality especially in the Chihuahuan Desert region along US-Mexico border. The objective of the study was to determine the effect of road dust texture and vehicular speed on airborne PM concentrations from different unpaved rural roads using two sampling techniques (DustTrak R , and Sticky-tape). The surface soil textures of unpaved roads varied from silty clay to loam with less than 4% soil moisture content at the time of PM measurement. Sticky tape method in seven experiment sites showed that PM ranged from 0.529 to 3.054 mg m -3 , and DustTrak R measurements showed that PM 2.5 concentration ranged from 1.11 to 37.1 mg m-3 at 1 m height. An exponential relationship was obtained between PM 2.5 by DustTrak R and vehicle speeds with an average slope of -1.619 mg m -3 s -1 . The concentration of PM measured with the Sticky-tape decreased with increasing height of measurement. Both PM measurement techniques provided a good approximation of PM emissions at different vehicles speeds, unpaved roads and position of the instrument above ground level for a variety of unpaved roads. The low cost sticky tape method has the potential to further determine and abiotic (elemental composition) and biotic (fungus) particles in airborne PM.

Different forms of copper and kinetin impacted element accumulation and macromolecule contents in kidney bean (Phaseolus vulgaris) seeds

The relationship between engineered nanomaterials and plant biostimulants is unclear. In this study, kidney bean (Phaseolus vulgaris) plants were grown to maturity (90 days) in soil amended with nano copper (nCu), bulk copper (bCu), or copper chloride (CuCl2) at 0, 50, or 100 mg kg-1, then watered with 0, 10, or 100 μM of kinetin (KN). Seeds were harvested and analyzed via ICP-OES and biochemical assays. While seed production was largely unaffected, nutritional value was significantly impacted. Accumulation of Cu was enhanced by 5-10% from controls by Cu-based treatments. Fe was the only macro/microelement significantly altered by nCu, which was ~29% lower than seeds from untreated plants. All forms of Cu combined with 10 μM KN reduced Mg from 9 to 12%. Application of KN plus bCu or CuCl2 elevated concentrations of Mn (31-41%) and S (19-22%), respectively. Protein content of seeds was stimulated (11-12%) by bCu, on average, and depressed by CuCl2 + KN (up to 22%). Variations in sugar and starch content were insignificant, compared to controls. Our results indicate that the interaction Cu × KN significantly altered the nutritional value of common beans, which has potential implications to agricultural practices incorporating Cu as either a pesticide or fertilizer.

Copper oxide nanoparticles and bulk copper oxide, combined with indole-3-acetic acid, alter aluminum, boron, and iron in Pisum sativum seeds

The interaction of CuO nanoparticles (nCuO), a potential nanopesticide, with the growth hormone indole-3-acetic acid (IAA) is not well understood. This study aimed to evaluate the nutritional components in seeds of green pea (Pisum sativum) cultivated in soil amended with nCuO at 50 or 100mgkg-1, with/without IAA at 10 or 100μM. Similar treatments including bulk CuO (bCuO) and CuCl2 were set as controls. Bulk CuO at 50mgkg-1 reduced seed yield (52%), compared with control. Bulk CuO at 50mgkg-1 and nCuO at 100mgkg-1, plus IAA at 100μM, increased iron in seeds (41 and 42%, respectively), while nCuO at 50mgkg-1, plus IAA at 100μM reduced boron (80%, respect to control and 63%, respect to IAA at 100μM). IAA, at 10μM increased seed protein (33%), compared with control (p≤0.05). At both concentrations IAA increased sugar in seeds (20%). Overall, nCuO, plus IAA at 10μM, does not affect the production or nutritional quality of green pea seeds.

Mule deer forage availability and quality at the Chihuahuan Desert rangelands, Mexico after a severe three-year drought

Abstract Mule deer historic range in Mexico has declined dramatically in the last decade. Forage availability and quality at the Chihuahuan Desert may play an important role sustaining populations at the southern end of their current distribution. We evaluated forage availability and quality at the end of a 3-year drought at two different localities in the Chihuahuan Desert: Old Net and Pulpit, we measured plant availability and quality, diet content and calculated diet preference indices. Vegetation at Old Net consisted primarily of both succulents (47%) and trees-shrubs (42%) while Pulpit had more grasses (60%) and herbs (24%) (P < 0.005). Feces collected at the Pulpit presented a high proportion of herbs (44%), while those collected at Old Net contained more trees and shrubs (53%). Preference index suggests that mule deer prefer herbs and overlook grasses, but there is no strong selection for any particular plant. Our results suggest that forage is appropriate to sustain mule deer populations, however, we found considerable variation in both localities suggesting a patchy landscape. More information regarding forage nutritional status and diet preferences can enhance our understanding on mule deer population dynamics in the Chihuahuan Desert.

Microbial and size characterization of airborne particulate matter collected on sticky tapes along US–Mexico border

Particulate matter (PM) emissions from various sources can affect significantly human health and environmental quality especially in the Chihuahuan Desert region along US-Mexico border. The objective of this study was to use the low-cost sticky tape method to collect airborne PM for size characterization and identification of fungal spores. Sticky tape samplers were placed at 1.0 and 2.0m above the ground surface at experimental sites in Ciudad Juárez, Mexico and at 0.6, 1.2 and 1.8m at New Mexico sites, USA. Soil samples were collected in both countries to determine fungal diversity, texture and moisture content. Dust particles collected from all of the experimental sites had a dominant texture of clay (<0.002mm). The dominant textures identified from soil samples collected from the US and Mexican sites were loam and sandy clay loam, respectively. Alternaria, Penicillium and Fusarium were frequently found funguses in the US sites while Alternaria and Aspergillus were commonly observed in the Mexican sites. The sticky tapes also showed a similar diversity of fungal microorganisms present in the airborne PM at both Mexico and US sites. Alternaria, Penicillium and Aspergillus were the three groups of airborne fungal microorganisms consistently present in the US and Mexican sites. The low-cost sticky tape method has the potential to be used for characterizing different airborne microorganisms and dust particles.

Particulate Matter: Capture and Quantification in Natural and Anthropogenic Sources

Air pollution has a category of pollutants called particulate matter (PM) emitted into the environment as one of the six principal pollutants. High concentrations of PM, of any category, can be found in natural and anthropogenic phenomenon known as dust storms. Such concentrations in this phenomenon can reach 6000 μg/m3, and at the same time large amounts of dust that accumulate in these events, reduce visibility at one kilometer, and also the path followed by this dust can reach distances exceeding thousands of kilometers. Recent epidemiological studies have shown a relationship between particulate matter and the environment in their health effects. For full extent implies the presence of PM in our daily lives, the objective of this review article is to present the information necessary to determine techniques that focus on monitoring air quality during dust storms and other events with similar characteristics, based on experiments conducted by researchers around the world in agriculture, industrial and unpaved zones.

Traditional and Molecular Studies of the Plant Pathogen Phytophthora capsici: A Review

Phytophthora capsici is responsible for large worldwide economic losses and is considered one of the limiting factors in the production of many crops [1]. More than 50 vegetable species have been identified as hosts of this plant pathogen [1,2]. Recently, two leguminous species, Phaseolus vulgaris [3], and Phaseolus lunatus [4], have been identified as hosts of this oomycete. Losses of up to 100% of the crop con occur in fields due to the incidence of this pathogen [5].