Using zebrafish (Danio rerio) to study the behavioral impacts of early bisphenol F exposure reveals decreased swim speed, increased distance between fish, and increased freezing behaviors

The widespread use of endocrine disrupting chemicals (EDCs) has been a source of concern because of their various effects on the endocrine system. These effects include metabolic disorders, complications in reproductive health, hormone-related cancers, and neurodevelopmental disorders. Of particular concern is bisphenol A (BPA), a synthetic compound commonly found in consumer products such as water bottles, thermal receipt paper, and epoxy resins used in processed food packaging. Previous studies have shown that BPA can mimic estrogen through a variety of mechanisms and thus elicit an endocrine response. Some manufacturers have responded by removing BPA from their products; however, studies using a replacement compound bisphenol S have reported it to be just as, if not more, dangerous. The use of zebrafish (Danio rerio) larvae as a model organism allows for the effects of bisphenol exposure to be rapidly quantified through a simple behavioral assay. In studies involving bisphenol exposure, the use of zebrafish has demonstrated reproductive, developmental, endocrine, and behavioral effects. The study of bisphenol F, yet another endocrine disruptor that has become a replacement for BPA in consumer products, is highly important to public safety

Effects of endocrine-disrupting chemical exposure on zebrafish ovarian follicles

The process of oocyte maturation involves both nuclear and cytoplasmic events that are essential for the production of viable eggs and subsequent fertilization in sexually reproducing animals. In zebrafish, oocyte nuclear maturation (meiotic resumption) is marked by a transition from opaque to translucent ovarian follicles. This transition is called clearing and results from germinal vesicle breakdown (GVBD) and the transformation of vitellogenin into yolk proteins. Oocyte maturation can be perturbed by endocrine-disrupting chemicals (EDCs). These EDCs have been broadly shown to interfere with reproductive development. Many herbicides and pesticides used agriculturally act as EDCs. These chemicals can enter aquatic ecosystems via runoff and erosion. To evaluate the effects of EDCs on zebrafish oocyte maturation, zebrafish ovarian follicles were cultured and exposed to various concentrations of either atrazine, 2,4-D, or diazinon. Follicles were evaluated at 2, 3, and 4 hours for size and viability, but clearing was assessed only at 4 hours post-exposure. Atrazine and diazinon significantly reduced follicle clearing at the tested concentrations. No effect was observed with 2,4-D exposure. At low enough concentrations, none of the chemicals produced endocrine-disrupting effects. The results suggest that at or above environmentally relevant concentrations, some EDCs impair oocyte maturation in exposed zebrafish follicles. The results support the need to monitor EDC exposure to prevent harmful effects not only on aquatic organisms, but also on humans and wildlife that are also exposed to these contaminants

Spontaneous Ignition Characteristics of Hydrocarbon Fuel-air Mixtures

Although the subject of spontaneous ignition of liquid fuels has received considerable attention in the past, the role of fuel evaporation in the overall spontaneous ignition process is still unclear. A main purpose of this research is to carry out measurements of ignition delay times, using fuels of current and anticipated future aeronautical interest, at test conditions that are representative of those encountered in modern gas turbine engines. Attention is focused on the fuel injection process, in particlar the measurement and control of man fuel drop size and fuel-air spatial distribution. The experiments are designed to provide accurate information on the role of fuel evaporation processes in determining the overall ignition delay time. The second objective is to examine in detail the theoretical aspects of spontaneous ignition in order to improve upon current knowledge and understanding of the basic processes involved, so that the results of the investigation can find general and widespead application

Environmental Policy Since Earth Day I: What Do We Know About the Benefits and Costs?

Data on costs and benefits of the major environmental laws passed during the 1970s are reviewed. The winners in terms of benefit-cost analysis include: getting lead out of gasoline, controlling particulate air pollution, reducing the concentration of lead in drinking water, and the cleanup of hazardous waste sites with the lowest cost per cancer case avoided under Superfund. The losers include: mobile source air pollution control, water pollution control, and many of the regulations and cleanup decisions taken under the Federal Insecticide, Fungicide, and Rodenticide Act, the Toxic Substances Control Act, the Safe Drinking Water Act, and Superfund.Environmental Economics and Policy,

Electronic structure Fermi liquid theory of high Tc superconductors: Comparison of predictions with experiments

Predictions of local density functional (LDF) calculations of the electronic structure and transport properties of high T(sub c) superconductors are presented. As evidenced by the excellent agreement with both photoemission and positron annihilation experiments, a Fermi liquid nature of the 'normal' state of the high T(sub c) superconductors become clear for the metallic phase of these oxides. In addition, LDF predictions on the normal state transport properties are qualitatively in agreement with experiments on single crystals. It is emphasized that the signs of the Hall coefficients for the high T(sub c) superconductors are not consistent with the types of dopants (e.g., electron-doped or hole-doped) but are determined by the topology of the Fermi surfaces obtained from the LDF calculations

Mind-reading versus neuromarketing: how does a product make an impact on the consumer?

Purpose – This research study aims to illustrate the mapping of each consumer’s mental processes in a market-relevant context. This paper shows how such maps deliver operational insights that cannot be gained by physical methods such as brain imaging. Design/methodology/approach – A marketed conceptual attribute and a sensed material characteristic of a popular product were varied across presentations in a common use. The relative acceptability of each proposition was rated together with analytical descriptors. The mental interaction that determined each consumer’s preferences was calculated from the individual’s performance at discriminating each viewed sample from a personal norm. These personal cognitive characteristics were aggregated into maps of demand in the market for subpanels who bought these for the senses or for the attribute. Findings – Each of 18 hypothesized mental processes dominated acceptance in at least a few individuals among both sensory and conceptual purchasers. Consumers using their own descriptive vocabulary processed the factors in appeal of the product more centrally. The sensory and conceptual factors tested were most often processed separately, but a minority of consumers treated them as identical. The personal ideal points used in the integration of information showed that consumers wished for extremes of the marketed concept that are technologically challenging or even impossible. None of this evidence could be obtained from brain imaging, casting in question its usefulness in marketing. Research limitations/implications – Panel mapping of multiple discriminations from a personal norm fills three major gaps in consumer marketing research. First, preference scores are related to major influences on choices and their cognitive interactions in the mind. Second, the calculations are completed on the individual’s data and the cognitive parameters of each consumer’s behavior are aggregated – never the raw scores. Third, discrimination scaling puts marketed symbolic attributes and sensed material characteristics on the same footing, hence measuring their causal interactions for the first time. Practical implications – Neuromarketing is an unworkable proposition because brain imaging does not distinguish qualitative differences in behavior. Preference tests are operationally effective when designed and analyzed to relate behavioral scores to major influences from market concepts and sensory qualities in interaction. The particular interactions measured in the reported study relate to the major market for healthy eating. Originality/value – This is the first study to measure mental interactions among determinants of preference, as well as including both a marketed concept and a sensed characteristic. Such an approach could be of great value to consumer marketing, both defensively and creatively

Thrust chamber performance using Navier-Stokes solution

The viscous, axisymmetric flow in the thrust chamber of the space shuttle main engine (SSME) was computed on the CRAY 205 computer using the general interpolants method (GIM) code. Results show that the Navier-Stokes codes can be used for these flows to study trends and viscous effects as well as determine flow patterns; but further research and development is needed before they can be used as production tools for nozzle performance calculations. The GIM formulation, numerical scheme, and computer code are described. The actual SSME nozzle computation showing grid points, flow contours, and flow parameter plots is discussed. The computer system and run times/costs are detailed