Applying phytochemical analysis in the pre-selection process of plant-based substrates for biomethanation: the case of avocado oil processing byproducts

Journal of Material Cycles and Waste Management - Phytochemicals in avocado oil processing byproducts were evaluated in this study. This information was used to make inferences use of these...     

Local varieties of cassava: conservation,cultivation and use in Uganda

The study explored the theory that on-farm conservation of cassava germplasm is influenced by farmers’ traditional and cultural preferences of particular varieties. Traditional knowledge practices that are used for on-farm conservation of cassava germplasm as well as cassava attributes for selection were assessed. The findings obtained from the study indicated that farmers use traditional knowledge to select and preserve cassava germplasm for future use. It was also clear that farmers have their preferences such as culinary attributes, storability in the ground, early maturity and cooking quality to mention but a few that influence the decisions taken to retain or abandon cultivation of varieties. Therefore, by planting varieties in multiples plots, replanting immediately after harvesting, sharing with others in the community and planting disease-free materials, farmers ensure that they preserve varieties of interest for decades. The information generated during this study could inform development policies tailored toward ensuring sustainable on-farm conservation of cassava genetic resources.     

Experimental study on electrostatic charging of polymer powders in mixing processes

Powder mixing is often carried out in the chemical and pharmaceutical industries. Electrostatic charges generated on polymer powders during mixing may lead to electrostatic problems due to the poor conductivity of those powders. In this study, we investigated the electrostatic charges, surface potential, and apparent volume resistivity of sample powders using a simple mixing device utilizing the Faraday cup method. To neutralize the charged powders, we also applied an AC-type ionizer in the mixing study. A commercial polyethylene powder with a mean particle size of 585 μm was tested in this experiment. The charge-to-mass ratios at the end of 600 s of mixing were ?0.075 nC/g at 295 rpm agitation speed, ?0.21 nC/g at 495 rpm, and ?0.31 nC/g at 660 rpm, high enough to cause electrostatic agglomeration and adhesion. The electric fields based on the surface potential on the powders were several hundreds of V/cm, too small to give rise to brush discharge. The apparent volume resistivity of powders estimated by a simple measurement system is 1.0 × 10¹⁶ Ωm, in reasonable agreement with that acquired by the conventional test cell method (5.9 × 10¹⁵ Ωm). The charging level on the polymer powders was reduced with an AC-ionizer.     

Can Nutrient Spiralling be Used to Detect Seasonal Nutrient Uptake in a Forested Stream?

Nutrient spiralling measurements were conducted in Lyrebird Creek, a forested stream in the Dandenong Ranges, Victoria, Australia. Spiralling indices from several nutrient (, ) enrichment experiments were correlated with seasonal variation in factors thought to control nutrient uptake, i.e., temperature, light and algal biomass. It was hypothesized that nutrient uptake would be higher in summer as increased temperatures would promote both biotic and abiotic processes and higher light levels in summer would stimulate photosynthesis. However, results did not support this hypothesis. Uptake length for and and uptake velocity were not correlated with chlorophyll-a, light or temperature (r ² < 0.30, P > 0.1) despite the seasonality of these biophysical factors (r ² > 0.42, P < 0.02). Lyrebird Creek might had no seasonal trend in nutrient uptake and/or nutrient spiraling measurements only appears suitable for contrasting streams with large differences in biophysical factors that supports biotic and abiotic nutrient processing. In addition, small errors in measuring a nutrient concentration can result in a large range in the estimated S _w and increased difficulty in determining significant differences in nutrient spiralling indices.     

Forecasting Peak Daily Ozone Levels: Part 2—A Regression with Time Series Errors Model Having a Principal Component Trigger to Forecast 1999 and 2002 Ozone Levels

Abstract

A modified time series approach, a Box-Jenkins regression with time series errors (RTSE) model plus a principal component (PC) trigger, has been developed to forecast peak daily 1-hr ozone (O₃) in real time at the University of Wisconsin-Milwaukee North (UWM-N) during 1999 and 2002. The PC trigger acts as a predictor variable in the RTSE model. It tries to answer the question: will the next day be a possible high O₃ day? To answer this question, three PC trigger rules were developed: (1) Hi-Low Checklist, (2) Discriminant Function Approach I, and (3) Discriminant Function Approach II. Also, a pure RTSE model without including the PC trigger and a persistence approach were tested for comparison. The RTSE model with DFA I successfully forecast the only two 1-hr federal exceedances (124 ppb), one in 1999 and one in 2002. In terms of the O₃ 100-ppb exceedances, 60–80% of the incorrect forecasts occurred with incorrect PC decisions. A few others may have been caused by unexpected O_3- weather relations. When the three approaches used UWM-N data to forecast a 100-ppb exceedance somewhere in the Milwaukee, WI, metropolitan area, their performance was dramatically improved: the false alarm rate was reduced from 0.89 to 0.44, and the probability of detection was increased from 0.71 to 0.88.     

Spatiotemporal variation of macroinvertebrates in relation to canopy cover and other environmental factors in Eriora River, Niger Delta, Nigeria

Canopy cover is well known to influence the distribution of macroinvertebrates in temperate streams. Very little is known about how this factor influences stream communities in Afrotropical streams. The effects and possible interactions of environmental factors and canopy cover on macroinvertebrate community structure (abundance, richness, and diversity) were examined in four stations in Eriora River, southern Nigeria bimonthly from May to November 2010. The river supported diverse macroinvertebrates in which the upstream sampling stations with dense canopy cover were dominated by Decapoda, Ephemeroptera, Odonata, Gastropoda, Trichoptera, and Coleoptera while Diptera and Coleoptera were the benthic organisms found predominant at downstream stations with less canopy cover. Some caddisfly species such as Agapetus agilis, Trichosetodes species and the stonefly Neoperla species were present upstream and were found to be potential bioindicators for a clean ecosystem. The blood worm Chironomus species and Tabanus sp. were abundant at the downstream of the river and are considered potential bioindicators for an organically degrading ecosystem. Some environmental factors varied temporally with significantly higher macroinvertebrate abundance and richness in May. We found out that canopy cover and environmental factors affected macroinvertebrates abundance, diversity, and richness and that the individual taxon had varying responses to these factors. These results help identify the mechanisms underlying the effects of canopy cover and other environmental factors on Afrotropical stream invertebrate communities.     

Monitoring Mammal Populations in Costa Rican Protected Areas under Different Hunting Restrictions

Abstract: It is necessary to assess whether the management of protected areas is achieving the objectives set for them. In particular, changes and trends in wildlife populations should be documented. We compared the 1990 abundance of mammals in two Costa Rican protected areas, Corcovado National Park (CNP) and Golfo Dulce Forest Reserve (GDFR), with similar environmental characteristics but different hunting restrictions and levels of protection. We also monitored the abundance of mammals in CNP over a 4-year period. We also devised an inexpensive method of monitoring tropical rainforest mammal populations in a timely and efficient manner. The method is based on the use of mammal track records and arboreal mammal sightings and requires little effort. With this method 20 mammal species were recorded at CNP and 15 at GDFR. Species were consistently less abundant in GDFR than in CNP, principally those species preferred by hunters. Species were grouped according to whether or not they are used as food and whether they are locally or globally threatened or not threatened. The abundance of all these groups of species in GDFR was 6–28% the abundance in CNP. During 1990–1994, overall mammal abundance in CNP remained relatively stable, but there was considerable variability among species. As a group, both species used for food and globally threatened species declined in abundance during that period in CNP. The abundance of all groups of species declined from 1992 to 1994, coinciding with a reduction in hunting vigilance at CNP. Evidence suggests that the main factor differentiating the abundance of mammals in the two protected areas, and at CNP during the study period, was the level of hunting. Golfo Dulce Forest Reserve seems to be achieving only partial success in protecting wildlife, whereas Corcovado National Park seems to be considerably more effective, although not entirely successful.     

Identifying correlates of success and failure of native freshwater fish reintroductions

Reintroduction of imperiled native freshwater fish is becoming an increasingly important conservation tool amidst persistent anthropogenic pressures and new threats related to climate change. We summarized trends in native fish reintroductions in the current literature, identified predictors of reintroduction outcome, and devised recommendations for managers attempting future native fish reintroductions. We constructed random forest classifications using data from 260 published case studies of native fish reintroductions to estimate the effectiveness of variables in predicting reintroduction outcome. The outcome of each case was assigned as a success or failure on the basis of the author's perception of the outcome and on whether or not survival, spawning, or recruitment were documented during post‐reintroduction monitoring. Inadequately addressing the initial cause of decline was the best predictor of reintroduction failure. Variables associated with habitat (e.g., water quality, prey availability) were also good predictors of reintroduction outcomes, followed by variables associated with stocking (e.g., genetic diversity of stock source, duration of stocking event). Consideration of these variables by managers during the planning process may increase the likelihood for successful outcomes in future reintroduction attempts of native freshwater fish. Identificación de Correlaciones de Éxito y Fracaso de Reintroducciones de Peces de Nativos Agua Dulce