666 research outputs found

    Environmental Fate and Effects of Bacillus thuringiensis (Bt) Proteins from Transgenic Crops:  a Review

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    This paper reviews the scientific literature addressing the environmental fate and nontarget effects of the Cry protein toxins from Bacillus thuringiensis (Bt), specifically resulting from their expression in transgenic crops. Published literature on analytical methodologies for the detection and quantification of the Cry proteins in environmental matrices is also reviewed, with discussion of the adequacy of the techniques for determining the persistence and mobility of the Bt proteins. In general, assessment of the nontarget effects of Bt protein toxins indicates that there is a low level of hazard to most groups of nontarget organisms, although some investigations are of limited ecological relevance. Some published reports on the persistence of the proteins in soil show short half-lives, whereas others show low-level residues lasting for many months. Improvements in analytical methods will allow a more complete understanding of the fate and significance of Bt proteins in the environment

    Overview of Instructional Technology Used in the Education of Occupational Therapy Students: A Survey Study

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    The purpose of this study was to explore the type of instructional technology (IT) master’s degree level occupational therapy educational programs routinely use as a part of their lecture- and laboratory-based instruction. Surveying the administrators of 121 graduate occupational therapy programs in the United States, we found that the majority of the respondents identified their program as using IT in some form for lecture-based courses, with less inclusion of IT for laboratory-based courses. Hybrid instruction, with the majority of the content being delivered face-to-face and the remainder via online, were the trends among the respondents. The findings also indicated that the respondents’ programs avoid certain IT, including synchronous online chat rooms or instant messaging, digital image collections, blogs or online journaling, Wikis, and audio/video podcasting. Few of the respondents said their programs had made a significant leap into implementing a larger online presence with instructional technology

    When evolution is the solution to pollution : key principles, and lessons from rapid repeated adaptation of killifish (Fundulus heteroclitus) populations

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    © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Evolutionary Applications 10 (2017): 762–783, doi:10.1111/eva.12470.For most species, evolutionary adaptation is not expected to be sufficiently rapid to buffer the effects of human-mediated environmental changes, including environmental pollution. Here we review how key features of populations, the characteristics of environmental pollution, and the genetic architecture underlying adaptive traits, may interact to shape the likelihood of evolutionary rescue from pollution. Large populations of Atlantic killifish (Fundulus heteroclitus) persist in some of the most contaminated estuaries of the United States, and killifish studies have provided some of the first insights into the types of genomic changes that enable rapid evolutionary rescue from complexly degraded environments. We describe how selection by industrial pollutants and other stressors has acted on multiple populations of killifish and posit that extreme nucleotide diversity uniquely positions this species for successful evolutionary adaptation. Mechanistic studies have identified some of the genetic underpinnings of adaptation to a well-studied class of toxic pollutants; however, multiple genetic regions under selection in wild populations seem to reflect more complex responses to diverse native stressors and/or compensatory responses to primary adaptation. The discovery of these pollution-adapted killifish populations suggests that the evolutionary influence of anthropogenic stressors as selective agents occurs widely. Yet adaptation to chemical pollution in terrestrial and aquatic vertebrate wildlife may rarely be a successful “solution to pollution” because potentially adaptive phenotypes may be complex and incur fitness costs, and therefore be unlikely to evolve quickly enough, especially in species with small population sizes.National Science Foundation Grant Numbers: DEB-1265282, OCE-1314567, DEB-1120263; National Institutes of Environmental Health Sciences Grant Numbers: R01ES021934-01, P42ES007381; Postdoctoral Research Program at the US Environmental Protection (US EPA); Office of Research and Development; Oak Ridge Institute for Science and Education (ORISE) Grant Number: DW92429801; US Department of Energ

    Subacute Effects of Cry1Ab Bt

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    A Perspective on Livestock–Wolf Interactions on Western Rangelands

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    The reintroduction of wolves into their historical ranges in the North American Rocky Mountains and areas of the southwestern United States is possibly one of the most ambitious ecosystem restoration efforts of the recent past. This initiative has been controversial and has stimulated considerable debate among concerned stakeholders about the feasibility of harmonizing multiple land-use demands when preservation of a large predator becomes a central management goal. In many areas, ranching has taken center stage of this debate as ranchers and land managers seek to develop sustainable ways to manage livestock on landscapes with wolves. The challenges associated with wolf restoration programs vary regionally and depend on a myriad of interacting factors. Wolf population size and consequent regulatory and legal frameworks; site-specific, biophysical features; and local traditions, perceptions, and attitudes of urban vs. ranching communities are only a few of the issues driving the diversity of situations. Because of this complexity, “silver-bullet” approaches are unlikely to provide answers that will satisfy all stakeholders in all locations. In this context, our article seeks to 1) provide a science-based perspective to inform the wolf–livestock ongoing debate; and 2) suggest research approaches that could lead to locally relevant solutions. Of paramount importance is better understanding of direct and indirect effects of wolves on livestock, and development of effective methods for minimizing impacts while maintaining ecologically relevant wolf populations on the landscape. We argue that progress (i.e., optimizing coexistence or minimizing conflict) is most likely if multiple tools and techniques are used in a context-dependent fashion and integrated into a science based operation supported by producers

    A Hybrid Lagrangian Variation Method for Bose-Einstein Condensates in Optical Lattices

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    Solving the Gross--Pitaevskii (GP) equation describing a Bose--Einstein condensate (BEC) immersed in an optical lattice potential can be a numerically demanding task. We present a variational technique for providing fast, accurate solutions of the GP equation for systems where the external potential exhibits rapid varation along one spatial direction. Examples of such systems include a BEC subjected to a one--dimensional optical lattice or a Bragg pulse. This variational method is a hybrid form of the Lagrangian Variational Method for the GP equation in which a hybrid trial wavefunction assumes a gaussian form in two coordinates while being totally unspecified in the third coordinate. The resulting equations of motion consist of a quasi--one--dimensional GP equation coupled to ordinary differential equations for the widths of the transverse gaussians. We use this method to investigate how an optical lattice can be used to move a condensate non--adiabatically.Comment: 16 pages and 1 figur

    Development of the morpholino gene knockdown technique in Fundulus heteroclitus : a tool for studying molecular mechanisms in an established environmental model

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    Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Aquatic Toxicology 87 (2008): 289-295, doi:10.1016/j.aquatox.2008.02.010.A significant challenge in environmental toxicology is that many genetic and genomic tools available in laboratory models are not developed for commonly used environmental models. The Atlantic killifish (Fundulus heteroclitus) is one of the most studied teleost environmental models, yet few genetic or genomic tools have been developed for use in this species. The advancement of genetic and evolutionary toxicology will require that many of the tools developed in laboratory models be transferred into species more applicable to environmental toxicology. Antisense morpholino oligonucleotide (MO) gene knockdown technology has been widely utilized to study development in zebrafish and has been proven to be a powerful tool in toxicological investigations through direct manipulation of molecular pathways. To expand the utility of killifish as an environmental model, MO gene knockdown technology was adapted for use in Fundulus. Morpholino microinjection methods were altered to overcome the significant differences between these two species. Morpholino efficacy and functional duration were evaluated with molecular and phenotypic methods. A cytochrome P450-1A (CYP1A) MO was used to confirm effectiveness of the methodology. For CYP1A MO-injected embryos, a 70% reduction in CYP1A activity, a 86% reduction in total CYP1A protein, a significant increase in β-naphthoflavone-induced teratogenicity, and estimates of functional duration (50% reduction in activity 10 dpf, and 86% reduction in total protein 12 dpf) conclusively demonstrated that MO technologies can be used effectively in killifish and will likely be just as informative as they have been in zebrafish.This work was funded in part by the National Institute of Environmental Health Sciences through the Duke Superfund Basic Research Center (P42ES010356), the Boston University Superfund Basic Research Program (P42ES007381), and the Duke Integrated Toxicology and Environmental Health Program (ES-T32-0007031). Additional support was provided by a U.S. Environmental Protection Agency STAR fellowship awarded to C.R.F

    A Hybrid Lagrangian Variational Method for Bose–Einstein Condensates in Optical Lattices

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    Solving the Gross–Pitaevskii (GP) equation describing a Bose–Einstein condensate (BEC) immersed in an optical lattice potential can be a numerically demanding task. We present a variational technique for providing fast, accurate solutions of the GP equation for systems where the external potential exhibits rapid variation along one spatial direction. Examples of such systems include a BEC subjected to a one-dimensional optical lattice or a Bragg pulse. This variational method is a hybrid form of the Lagrangian variational method for the GP equation in which a hybrid trial wavefunction assumes a Gaussian form in two coordinates while being totally unspecified in the third coordinate. The resulting equations of motion consist of a quasi-one-dimensional GP equation coupled to ordinary differential equations for the widths of the transverse Gaussians. We use this method to investigate how an optical lattice can be used to move a condensate non-adiabatically

    Urban Combat: The Ultimate Extreme Environment

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