Hood Technology (United States)

Abstract As keystone species, apex predators play a role in structuring most ecosystems through competition and facilitation, thereby affecting community structure, prey abundance and behavior, vegetation, and abiotic processes. Apex predators are also highly threatened and have been extirpated from much of North America, leading to mesocarnivores, such as coyotes (Canis latrans), becoming de facto apex predators in many ecosystems. However, it is unknown if these mesocarnivores can fill the same functional keystone role as true apex predators. We compared the spatial and temporal habitat use of mesocarnivores in two similar study systems, one with pumas (Puma concolor) and one without, to determine how the role of coyotes in structuring the carnivore community changes in the absence of pumas. We used multispecies occupancy and relative abundance models to examine the spatial avoidance of pumas and coyotes by the smaller mesocarnivores, and temporal overlap and avoidance‐attraction ratios to examine temporal avoidance. We found that coyotes partially fill the functional role of apex predators, but with weaker effects than pumas. Where pumas were absent, site use intensity and relative abundance increased for coyotes (180% and 1250%) and raccoons (Procyon lotor, 308% and 3273%) and decreased for bobcats (Lynx rufus, 36% and 55%), gray foxes (Urocyon cinereoargenteus, 13% and 32%), and striped skunks (Mephitis mephitis, 3% and 12%). Coyotes and raccoons shifted their temporal activity away from pumas, while gray foxes shifted their activity closer to pumas. Detection likelihood decreased for all species after detection of a puma (67%–93%) or coyote (46%–94%) in both sites, but small mesocarnivores avoided pumas more than coyotes in the study area with both. Interactions between carnivores are complex and best understood with multiple measures and in the context of the full community. While coyotes appear to suppress smaller mesocarnivores by some measures (e.g., temporal avoidance), they do not by others (e.g., spatial avoidance) and have overall weaker effects than pumas. Our results suggest that coyotes are not a substitute for apex predators, and conserving true apex predators is likely important for maintaining ecosystem health.

A complete understanding of European pears in response to 1-MCP would deliver high-quality pears with a crispy-juicy texture to consumers. 1-MCP reduced the incidences of decay, internal browning, and scald, suppressed ethylene production rate and respiration rate, and retained high flesh firmness and peel chlorophyll content in “Concorde,” “Comice,” “Bosc,” and “Gem” pears after 7 months of regular-air storage plus a 5- or 7-day ripening period. Additionally, high levels of total phenolics and flavonoids, DPPH, and ferric reducing antioxidant power were found in the 1-MCP-treated “Comice” and “Gem” pears, but not in “Concorde” or “Bosc”. 1-MCP effectively extended the storage life of “Concorde,” “Bosc,” and “Gem” pears to 5, 7, and 7 months, respectively, with high scores of crispness and juiciness. Conversely, a hard mouthfeel with fair juicy and flavor was found in the 1-MCP-treated “Comice” pears after 7 months of RA storage plus a 5-day ripening at 20°C. Novelty impact statement 1-MCP retained the sensory attributes of flavor, juiciness, and crispness with low rates of disorders in “Concorde,” “Bosc,” and “Gem” pears over the 5, 7, and 7 months of regular-air storage period, respectively. However, the hard mouthfeel with fair sensory attributes of juicy and flavor was obtained in 1-MCP-treated “Comice” pears. For consumers that prefer a ripened pear, pear industries could deliver the regular-air-stored “Concorde,” “Comice,” “Bosc,” and “Gem” pears during 1–3, 1–5, 0.5–3, and 1–5 months of storage, respectively.

Bothriochloa ischaemum (Old World Bluestem) is a problematic invasive grass throughout the southern United States. We measured the long-term effects (12 years) of a single growing-season fire (September 2006) in a grassland dominated by Old World Bluestem. Prescribed fire drastically reduced Old World Bluestem cover (prefire: 76 ± 4% [mean ± standard error], 2007: 8 ± 2%) and cover remained low (21 ± 6%) in 2018 with no additional management. Surprisingly, Old World Bluestem cover in unburned plots decreased 12% during the same time. After the burn, native graminoid cover peaked after 3 years (29 ± 7%) but decreased to 18 ± 5% by 2018, and native annual forb cover, almost absent before the fire, increased dramatically to 39 ± 7% in 2007, then quickly decreased to pre-burn levels. Native perennial forb cover more than doubled in 2007 and continued to increase to 58 ± 5% in 2018. A single growing-season fire greatly reduced the cover of Old World Bluestem, likely due to high fuel loads, low rainfall, and phenological timing; the fire also allowed perennial forbs to establish. Restoring dominance of native grasses after removal of this invasive species will require additional active restoration such as seeding or planting.

To model and forecast a monthly pine sawtimber (PST) stumpage price, $$y_t$$ , data collected across 11 southern states in the U.S., we adopt a new semiparametric approach where the first phase adopts a nonparametric method called “Time Series Central Subspace with Covariates” (TSCS-C) to extract sufficient information about $$y_t$$ through a univariate time series $$\{d_t\}$$ , which is a linear combination of a set of past values of $$y_t$$ and a high dimensional covariate vector $${{\mathbf {x}}}_t$$ of sale characteristics. Then, $$\{d_t\}$$ alone is used as the predictor series to build a parametric nonlinear time series model for $$y_t$$ . This yields a new semiparametric nonlinear time series model for $$y_t$$ . Assessment in terms of out-of-sample forecasts of monthly PST stumpage prices show that our semiparametric model with the covariate $${{\mathbf {x}}}_t$$ has the smallest average forecasting error compared to another semiparametric nonlinear time series model without $${{\mathbf {x}}}_t$$ and two other parametric counterparts based on multiplicative seasonal autoregressive integrated moving average models with and without $${{\mathbf {x}}}_t$$ . This data underscores the ability of our semiparametric approach to first reduce the dimensionality of $${{\mathbf {x}}}_t$$ and a set of past values of $$y_t$$ significantly using the TSCS-C nonparametric methodology and then to produce a superior nonlinear time series model.

Slight acidic electrolyzed water (SAEW) has been widely used in cleaning systems of fruit and vegetables. It strongly reduces microbial contamination. However, no information is available on whether SAEW offers the potential for fresh jujube cleaning. The purposes of this study were, first, to compare the effectiveness of SAEW with commercial sanitizers (i.e. sodium hypochlorite (NaClO) or calcium hypochlorite (Ca(ClO)2 )) on 'Jiancui' jujube; second, to determine the response of fruit decay, tissue calcium (Ca) content, and quality attributes to dip application of calcium nitrate (Ca(NO3 )2 ) by concentration; and third, to investigate the effects of SAEW combined with Ca(NO3 )2 or calcium acetate (Ca(OAc)2 )) on fruit Ca uptake, quality attributes, and bioactive compounds. Fruits washed with NaClO, Ca(ClO)2 , or an SAEW solution showed no difference in reduction of decay incidence. In contrast to NaClO treatment, SAEW or Ca(ClO)2 significantly retarded losses in fruit firmness (FF), green color (hue angle), and skin lightness (L*), and maintained intact pericarp tissue structure during storage at 1°C. Application of Ca(NO3 )2 at 5-10g L-1 effectively promoted Ca2+ uptake and minimized declines in FF and L* value but had no effect on decay development. Adding 10g L-1 Ca(NO3 )2 or Ca(OAc)2 to SAEW provided an additional benefit in increasing decay resistance, increasing Ca2+ into fruit and increasing levels of bioactive compounds in jujube fruit. SAEW in combination with Ca(NO3 )2 or Ca(OAc)2 has commercial potential for fresh jujube disinfection and improving storage quality as a result of the cleaning processes. © 2019 Society of Chemical Industry.

The Richmond Hill Mine heap leach pads (HLP 1&2, and HLP 3) were reclaimed in 1996 using a three-layer evapotranspiration (ET) cover designed to limit percolation of precipitation through the facilities. HLP seepage outflow rates have been measured on an approximately weekly basis. Large seasonal and wet/dry outflow cycles have been observed. Several years after the cover system installation, increased HLP drainage rates were observed, which could be due to increased permeability of the compacted layer in response to pedogenic processes such as wetting/drying, freeze/thaw, and root development. The estimated net infiltration rate during the monitoring period is about 34% of precipitation. To evaluate the cover system efficiency, a monthly time-step, spreadsheet based water balance model was created. The model considers close inter-relation between precipitation, ET, and cover net infiltration on a monthly scale and continuous feedback of water movement in the soil-plant-atmosphere continuum. The model accurately reproduced the recorded seepage rates for the monitoring period after pedogenic processes reach a stable condition.