Manifold Destiny: Migrant Deaths and Destinations in the Arizona Desert

This research theorizes a model for unauthorized border crosser (UBC) behavior when crossing the Mexico/U.S. border into Arizona. The manifold model developed here is a modified funneling effect of multiple trails converging together at nodes that separate into multiple exit points. Using hydrological metaphors, we quantify deathsheds into trails by using the remains of UBCs as trail markers and then compare the trails produced from three geostatistical research methods. The results may be used in designing search‐and‐rescue locations.     

Heat-induced aggregation of whey proteins: comparison of cheese WPC with acid WPC and relevance of mineral composition

Heat-induced aggregation of whey proteins in solutions made from two commercial whey protein concentrates (WPCs), one derived from mineral acid whey (acid WPC) and the other from cheese whey (cheese WPC), was studied using polyacrylamide gel electrophoresis (PAGE), size exclusion chromatography (SEC), and transmission electron microscopy (TEM). Heat treatment (75 degrees C) of acid WPC solutions (12.0%, w/w, pH 6.9) resulted in formation of relatively small "soluble" aggregates that were predominantly disulfide-linked. By contrast, heat treatment of the cheese WPC solutions (under the same conditions) caused formation of relatively large aggregates, containing high proportions of aggregates linked by noncovalent associations. The rate of aggregation of both beta-lactoglobulin and alpha-lactalbumin at 75 degrees C, measured as the loss of native proteins by PAGE, was higher in the cheese WPC solution than in the acid WPC solution. Cross dialysis of the two WPC solutions resulted in alteration of the mineral composition of each WPC solution and reversing their heat-induced aggregation behavior. The results demonstrated that the mineral composition is very important in controlling the aggregation behavior of WPC products.     

ACCUMULATION OF SILICON IN CYNODON DACTYLON X C. TRANSVAALENSIS AND POA TRIVIALIS USED AS AN OVERSEED GRASS

Calcium silicate has been used to supply silicon (Si) as a plant nutrient for enhancing crop production and the suppression of turf diseases. Research was initiated to determine the effect of calcium silicate on silicon uptake, turf quality, and its residual activity in providing plant available Si in two turfgrass systems. During 2005 and 2006, calcium silicate (CaSi, 12% Si) was applied as a topdressing at eight rates ranging from 0 to 342 kg m^?2 to a ‘Tifdwarf’ (Cynodon dactylon × C. transvaalensis Burtt Davy) green in the spring and to the same plots overseeded with ‘Wintergreen’ rough bluegrass (Poa trivialis L.) in the fall. At initiation of the study, dolomitic limestone and magnesium sulfate (MgSO₄) was applied to equilibrate calcium across all treatments based on the highest rate of CaSi. Every 28 days, treatments were rated for turf quality and then harvested to determine Si accumulation. One month after applying CaSi in 2005, Si concentration in the leaf tissue of Tifdwarf had increased linearly with increasing rates. This response continued through the months of May, June, July, August, and October with a 9%, 21%, 40%, 22% and 21% increase in Si concentration in the leaf tissue between the control and the 342 kg m^?2 rate, respectively. Although the rate response remained, there was an overall drop in average percent Si accumulation in leaf tissue across the treatments beginning three months after the first application. Similar responses were noted with the overseeded rough bluegrass with a 46%, 85%, 69%, 111% and 58% increase in Si concentration in the leaf tissue between the control and the 342 kg m^?2 rate, respectively. In contrast to the bermudagrass, over the five month period following application, the residual activity of Si in rough bluegrass remained high, suggesting that rough bluegrass might be a better Si accumulator in comparison to Tifdwarf bermudagrass. The second run of the experiment (2006–2007) and the residual trial had the same response with Si concentration in the leaf tissue increasing as the amount of CaSi applied increased. Although turfgrass quality was not well correlated to CaSi rate for Tifdwarf bermudagrass, there was an increase in quality ratings for rough bluegrass from December 2005 to April 2006.     

Investigation of ovicell hyperplasia in bryozoans chronically exposed to natural oil seepage

Systemic collection and examination of bryozoans from surface, subsurface and benthic kelp fronds in an area chronically exposed to natural oil seepage revealed no instances of ovicell hyperplasia. Reasons are presented to explain the contrast between these findings and reported ovicell hyperplasia in other species exposed to creosote and petroleum hydrocarbons.     

Logging Impacts in Tropical Lowland Humid Forest on Tree Species Diversity and Environmental Conservation

This study assessed the effects of exploitations in natural forest ecosystems on tree species diversity and environmental conservation. This was achieved by comparing tree species diversity and yield in an unlogged forest (Strict Nature Reserve) and a forest reserve where active logging is in progress in Ondo State, Nigeria. Eight plots (20 m × 20 m) were assessed in each site using systematic sampling techniques. All living trees with dbh >10 cm were identified, categorized into families with their diameter at breast height (dbh) measured in each plot. Shannon-Weiner and species evenness indices were used to assess and compare tree species diversity and abundance. The results show that the tropical humid forest is very rich in tree species, as a total of 54 different tropical hardwood species from 23 families were encountered in both forest types. There were 46 species distributed among 21 families in the unlogged forest and 24 species in 14 families in the logged forest. Shannon-Weiner diversity index of 3.16 and 3.03 and evenness index of .83 and .81 were also obtained for the unlogged and logged forest, respectively. Every variable computed had a higher value in the unlogged forest relative to the logged forest. In the unlogged forest, the species with the highest number of occurrence was Mansonia altissima A. Chev. (80 stems/ha). Caesalpinoidae and Sterculiaceae families had the highest number of species (6). In the logged forest, Triplochiton scleroxylon K. Schum. (18 stems/ha) had the highest frequency and Caesalpinoidae family has the highest number of species (4). The study concludes that exploitation has affected species diversity in the ecosystem and subsequently, the roles of trees in environmental conservation are affected.     

Mapping the territory: agroforestry awareness among Washington State land managers

There is growing interest in research to develop potential agroforestry models for temperate climates. In Washington State, recent studies and anecdotal information suggest that agroforestry is already employed by land managers, and if so, this experience should inform future research efforts. Because this population is not well defined, a mail survey was designed to: 1) Assess Washington land manager awareness of agroforestry, 2) assess perceptions of agroforestry as a land management tool, 3) assess the perceived potential opportunities or obstacles for land managers to practice agroforestry, and 4) identify landowner groups believed to be practicing agroforestry in Washington State.Three groups of land managers were surveyed: employees of the Soil Conservation Service (SCS), Washington State University Cooperative Extension Service (WSUCE) and OTHER, consisting of university faculty, private land managers, State and Federal land managers and owners of small natural resource businesses.Agroforestry was not a new concept for most (94%) respondents, further 55% of those familiar with agroforestry were practicing agroforestry or providing advice to landowners who were practicing agroforestry. Use in (government mandated) soil conservation plans on farmland (100% of all respondents) was the most frequently cited potential application for agroforestry in the state followed by range and pasture land and managing non-commercial forest land (both 84%), use on commercial forest plantation (83%) and fruit and nut orchards (61%).Diversifies land use (25%), enhanced productivity (18%), aesthetics (13%) and income diversity (13%) were the four most frequently cited potential advantages to practicing agroforestry. Lack of information (28%), lack of technical assistance (18%), establishment costs (14%) and not an established practice (14%) were the most frequently identified potential obstacles to practicing agroforestry. Respondents suggested there is great potential for application of agroforestry throughout the state, and non-industrial private forest land owners were selected for future study of this potential.     

One-day rate measurements for estimating net nitrification potential in humid forest soils

Measurements of net nitrification rates in forest soils have usually been performed by extended sample incubation (2–8 weeks), either in the field or in the lab. Because of disturbance effects, these measurements are only estimates of nitrification potential and shorter incubations may suffice. In three separate studies of northeastern USA forest soil surface horizons, we found that laboratory nitrification rates measured over 1 day related well to those measured over 4 weeks. Soil samples of Oa or A horizons were mixed by hand and the initial extraction of subsamples, using 2 mol L⁻¹ KCl, occurred in the field as soon as feasible after sampling. Soils were kept near field temperature and subsampled again the following day in the laboratory. Rates measured by this method were about three times higher than the 4-week rates. Variability in measured rates was similar over either incubation period. Because NO₃⁻ concentrations were usually quite low in the field, average rates from 10 research watersheds could be estimated with only a single, 1-day extraction. Methodological studies showed that the concentration of NH₄⁺ increased slowly during contact time with the KCl extractant and, thus, this contact time should be kept similar during the procedure. This method allows a large number of samples to be rapidly assessed.     

Analysis of airborne particles sampled in the southern Appalachian mountains

Over 3 yr of particulate measurements were made at two high elevation sites in the southern Appalachian Mountains of Tennessee and Virginia. Both dichotomous samplers and filter packs were used to obtain day and night, week-long samples for subsequent elemental and ionic analysis. Total No _inf3 ^sup? (HNO₃ + No _in3 ^sup? ) and SO _inf4 ^sup2? averaged, respectively, 1.1 and 5.0 µg m^?3 at Look Rock, Tennessee and 2.0 and 6.4 µg m^?3 at Whitetop Mountain, Virginia. At Whitetop Mountain, the spring and summer seasons had the highest average SO _inf4 ^sup2? concentrations. Seasonally, total N03 varied little. The diurnal variation of elements and SO _inf4 ^sup2? was small. Only total NO _inf3 ^sup? varied substantially with highest values during the day. The fine fraction (particle diameter < 2.5 µm) accounted for about 67% of the total mass. Fine mass and elemental concentrations were generally higher at Look Rock. The elements comprising the principal mass fraction of the coarse samples (2.5 gm < particle diameter < 10 to 15 µm) were of crustal origin (e.g., Al, Si, Ca, Fe) while the element comprising the principal mass fraction of the fine samples (i.e., S) was of manmade origin. Cluster analysis identified two groups of elements at Whitetop Mountain. These groups, in both the coarse and fine fraction, were associate with a soil and an automobile emission component. At Look Rock, only a soil component was obvious.     

Phospholipid-based microemulsions suitable for use in foods

The preparation of nonaqueous microemulsions using food-acceptable components is reported. The effect of oil on the formation of microemulsions stabilized by lecithin (Epikuron 200) and containing propylene glycol as immiscible solvent was investigated. When the triglycerides were used as oil, three types of phase behavior were noted, namely, a two-phase cloudy region (occurring at low lecithin concentrations), a liquid crystalline (LC) phase (occurring at high surfactant and low oil concentrations), and a clear monophasic microemulsion region. The extent of this clear one-phase region was found to be dependent upon the molecular volume of the oil being solubilized. Large molecular volume oils, such as soybean and sunflower oils, produced a small microemulsion region, whereas the smallest molecular volume triglyceride, tributyrin, produced a large, clear monophasic region. Use of the ethyl ester, ethyl oleate, as oil produced a clear, monophasic region of a size comparable to that seen with tributyrin. Substitution of some of the propylene glycol with water greatly reduced the extent of the clear one-phase region and increased the extent of the liquid crystalline region. In contrast, ethanol enhanced the clear, monophasic region by decreasing the LC phase. Replacement of some of the lecithin with the micelle-forming nonionic surfactant Tween 80 to produce mixed lecithin/Tween 80 mixtures of weight ratios (Km) 1:2 and 1:3 did not significantly alter the phase behavior, although there was a marginal increase in the area of the two-phase, cloudy region of the phase diagram. The use of the lower phosphatidylcholine content lecithin, Epikuron 170, in place of Epikuron 200 resulted in a reduction in the LC region for all of the systems investigated. In conclusion, these studies show that it is possible to prepare one-phase, clear lecithin-based microemulsions over a wide range of compositions using components that are food-acceptable.