Comparing experimental design schemes in predictive food microbiology: Optimal parameter estimation of secondary models

In predictive food microbiology, full factorial designs are still more the rule than the exception, despite the huge experimental workload and cost related to this method. In this study, two simulation studies for secondary square-root-type models are performed to compare several experimental designs with respect to four criteria: (i) number of experiments, (ii) goodness-of-fit statistics with respect to the original model structure, and (iii) accuracy and (iv) uncertainty of the parameter estimates. In addition, the effect of data quality, quantified as the error related to plate count measurements, is assessed on the relation between model structure and experimental design. Full factorial, reduced full factorial, central composite, Latin-square and Box-Behnken designs are evaluated and compared to randomly selected datasets.     

Invited review: A 2020 perspective on pasture-based dairy systems and products

Grazing pasture is the basis for dairy production systems in regions with temperate climates, such as in Ireland, New Zealand, parts of Australia, the United States, and Europe. Milk and dairy products from cows on pasture-based farms predominantly consuming fresh grazed grass (typically classified as “grass-fed” milk) have been previously shown to possess a different nutrient profile, with potential nutritional benefits, compared with conventional milk derived from total mixed ration. Moreover, pasture-based production systems are considered more environmentally and animal welfare friendly by consumers. As such, there is significant potential for market capitalization on grass-fed dairy products. As competition in this space increases, the regulations of what constitutes as grass-fed vary between different regions of the world. With this in mind, there is a need for clear and independently accredited grass-fed standards, defining the grass-fed criteria for labeling of products as such, subsequently increasing the clarity and confidence for the consumer. This review outlines the numerous effects of pasture production systems on dairy product composition, nutritional profile, and sustainability, and highlights potential future methods for authentication.     

Assessment of the contribution of irrigation to poverty reduction and sustainable livelihoods

Irrigation in developing countries tends to be stereotyped as equity reducing, in competition with other uses for scarce water resources, and often resulting in negative impacts for women and other disadvantaged groups. Agricultural intensification through the practice of irrigation as a strategy for poverty reduction is examined. There are four inter‐related mechanisms through which irrigated agriculture can reduce poverty. These are: improvements in the levels and security of productivity, employment and incomes for irrigating farm households and farm labour; the linkage and multiplier effects of agricultural intensification for the wider economy; provision of opportunities for diversification of rural livelihoods; and multiple uses of irrigation supply. There are also significant risks that badly designed and managed irrigation can negatively impact on poverty. It is concluded that irrigated farming varies widely in its form and impacts, and has diverse local attributes. Water resource management decisions must recognize this and be based on an holistic and livelihood‐centred assessment of irrigation benefits and costs that goes beyond food production objectives.     

Effect of temperature on the morphological and photovoltaic stability of bulk heterojunction polymer:fullerene solar cells

In high performance polymer:fullerene bulk heterojunction solar cells the nanoscale morphology of interpenetrating acceptor:donor materials is optimized through appropriate preparation conditions such as annealing and choice of solvent, but this initial state-of-the-art morphology will not remain stable during long-term operation. We report the effects of prolonged storage at elevated temperatures on both the morphology and the photovoltaic performance for the model systems MDMO-PPV:PCBM and P3HT:PCBM as compared to ‘High T_g PPV’:PCBM based solar cells, where the ‘High T_g PPV’ is characterized by its high glass transition temperature (138 °C). In situ monitoring of the photocurrent–voltage characteristics at elevated temperatures, in combination with a systematic transmission electron microscopy (TEM) study and complementary optical spectroscopy, reveals distinct degradation kinetics and morphological changes that indicate the occurrence of different underlying physico-chemical mechanisms.     

On the use of on-line detection for maintenance of gradually deteriorating systems

This paper deals with condition-based maintenance and non-stationary degradation process due to sudden changes. This is an attempt to propose an adaptive maintenance policy based on the on-line change detection procedure which can help to detect switches from a nominal mode to an accelerated mode in a non-informative context about the change mode time.     

The development of automatic numerosity processing in preschoolers: Evidence for numerosity-perceptual interference.

Three experiments examined developmental changes in the automatic processing of numerosity and perceptual information using a nonsymbolic numerical Stroop paradigm. In Experiments 1 and 2 (E1 and E2), 4-, 5-, and 6-year-olds had to compare the numerosities or the total filled areas of collections of dots (E1) or bars (E2) varying along both dimensions. Experiment 3 replicated E2's results in 3-, 4-, and 5-year-olds. Results demonstrated the existence of reciprocal influences between numerical and perceptual information beginning at age 3. Moreover, the irrelevant perceptual influences remained stable throughout development, whereas the sensitivity to irrelevant numerical cues tended to increase with age despite children's growing inhibition capacities. No significant correlation could be found between these developmental changes and the acquisition of counting knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How to compare small multivariate samples using nonparametric tests

In the life sciences and other research fields, experiments are often conducted to determine responses of subjects to various treatments. Typically, such data are multivariate, where different variables may be measured on different scales that can be quantitative, ordinal, or mixed. To analyze these data, we present different nonparametric (rank-based) tests for multivariate observations in balanced and unbalanced one-way layouts. Previous work has led to the development of tests based on asymptotic theory, either for large numbers of samples or groups; however, most experiments comprise only small or moderate numbers of experimental units in each individual group or sample. Here, we investigate several tests based on small-sample approximations, and compare their performance in terms of α levels and power for different simulated situations, with continuous and discrete observations. For positively correlated responses, an approximation based on [Brunner, E., Dette, H., Munk, A., 1997. Box-type approximations in nonparametric factorial designs. J. Amer. Statist. Assoc. 92, 1494–1502] ANOVA-Type statistic performed best; for responses with negative correlations, in general, an approximation based on the Lawley–Hotelling type test performed best. We demonstrate the use of the tests based on the approximations for a plant pathology experiment.     

Hydrodeoxygenation of Phenol on Beta Zeolite Catalysts

Biomass is considered the largest renewable energy source and an important alternative for biofuel production. The fast pyrolysis of biomass is an economical and advantageous to get bio-oil. However, bio-oil has a large amount of oxygenated compounds and needs upgrade. The catalytic process of HDO （hydrodeoxygenation） is the most efficient way to remove oxygen from the bio-oil. In this paper, it was studied the HDO phenol （300 ℃ and 35 atm） on catalysts based on cobalt or copper oxides supported on HBeta zeolite. The catalysts were characterized by XRD （X-ray diffraction）, FTIR （infrared spectroscopy） and NH3-TPD （desorption of ammonia）. The results showed the presence of CO304 （cobalt oxide） and CuO （copper oxide）. The measurements showed the presence of acid sites weak, moderate and strong and that the impregnation of the metal oxide modifying the acidity of the support. The results showed the following order HDO conversion： CoHBeta 〉 CuHBeta 〉 HBeta. The presence of the cobalt or copper catalysts contributes to the increase in conversion due to hydrogenation. All catalysts were selective to benzene, but only the impregnated catalysts showed selectivity to cyclohexane and cyclohexene.     

The effect of TiO2, pigmentation on the hydrolysis of amino resin crosslinked epoxy can coatings

Pigmented (TiO₂), amino resin crosslinked coatings, designed for applications in can coatings’ internal lacquers, were formulated, characterized, applied, and cured. Three grades of a pigmentary form of TiO₂ were characterized in terms of their particle size, their particle morphology, their zeta potential, and their moisture retention behavior. Epoxy coatings that were crosslinked using one of several, different amino crosslinkers were prepared. The effect of the presence of the TiO₂ pigments on the hydrolysis of the cured coatings was monitored via the controlled retorting of the coatings. The different grades of TiO₂ pigment were selected, to establish whether or not they could be used interchangeably with respect to hydrolysis and to melamine release. Also, the effects of the aging of the fluid coatings on the amount of melamine released from the coatings (after curing and retorting) were monitored. Storage under laboratory conditions for 2, 20, and 40 weeks was used for this purpose. The TiO₂ pigment contributed significantly to the hydrolysis behavior of the epoxy coatings in that their presence substantially reduced the amount of melamine released and the extent of crosslinker hydrolysis. Typical results show that excluding the TiO₂ pigment particles from the formulation results in there being 50% more hydrolysis of the crosslinker to melamine. With respect to the melamine release and crosslinker hydrolysis, the different grades of the pigment gave similar results.     

Selection for intrabody solubility in mammalian cells using GFP fusions

Single-chain antibody fragments (scFv) expressed in the cytoplasm of mammalian cells, also called intrabodies, have many applications in functional proteomics. These applications are, however, limited by the aggregation-prone behaviour of many intrabodies. We show here that two scFv with highly homologous sequences and comparable soluble expression levels in Escherichia coli cytoplasm have different behaviours in mammalian cells. When over-expressed, one of the scFv aggregates in the cytoplasm whereas the second one is soluble and active. When expressed at low levels, using a retroviral vector, as a fusion with the green fluorescent protein (GFP) the former does not form aggregates and is degraded, resulting in weakly fluorescent cells, whereas the latter is expressed as a soluble protein, resulting in strongly fluorescent cells. These data suggest that the GFP signal can be used to evaluate the soluble expression of intrabodies in mammalian cells. When applied to a subset of an E.coli-optimised intrabody library, we showed that the population of GFP+ cells contains indeed soluble mammalian intrabodies. Altogether, our data demonstrate that the requirements for soluble intrabody expression are different in E.coli and mammalian cells, and that intrabody libraries can be directly optimised in human cells using a simple GFP-based assay.