353 research outputs found

    Influence of high-temperature desiccation on physiology and chemical composition of hybrid maize (Zea mays L.) axis mitochondria

    Get PDF
    Hybrid maize (Zea mays L.) seed from desiccation-sensitive and desiccation-tolerant inbred lines B73 and A632, respectively, was harvested at moisture contents ranging from 500 to 400 g H2O kg-1 fw and preconditioned at 35°C for 0 to 48 h to study the effect of desiccation injury on axis mitochondrial function and chemical composition. Seed quality, as measured by the standard warm germination test and soil-free cold test, was high (\u3e95%) for all drying treatments. Although not as great as previously observed, high-temperature (45°C) desiccation had a deleterious effect on seed vigor of both genotypes. A632 was somewhat more desiccation-tolerant than B73, as evidenced by higher shoot weights, and preconditioning at 35°C increased desiccation tolerance of both hybrids. Differences in seed vigor among genotypes and drying treatments could not be fully explained by changes in mitochondrial composition. The ratio of raffinose: sucrose in axis tissue was lower for B73 than for A632, primarily due to the higher sucrose content of B73. Phosphatidylserine (PS) composition of axis mitochondria decreased and phosphatidylethanolamine (PE) composition increased with seed maturation, with generally higher levels of PS and lower levels of PE in B73 as compared to A632. Phosphatidylcholine (PC) composition increased as seeds became tolerant to high-temperature desiccation during preconditioning. The ratio of PC/PE in axis mitochondria was higher in B73 than A632 and increased with time of preconditioning. In contrast, the ratio of PC/PE decreased as high-temperature desiccation tolerance was induced during seed maturation. Mitochondria from B73 axes had higher levels of oleic (18:1) and lower levels of linoleic (18:2) acid as compared to A632. Isolated mitochondria exhibited similar rates of State 3 respiration regardless of genotype, harvest moisture, or preconditioning time. No State 4 respiration was observed. Electron microscopy revealed similar mitochondrial ultrastructure in dry axis tissue, regardless of genotype, preconditioning time, or harvest moisture. The mitochondria from embryonic tissues appeared to be typical of those found in dry seed not directly damaged by high-temperature desiccation. Thus mitochondria are buffered from damage either by their osmotic location and/or other physiological mechanisms

    Business Ethics and Ethics Education in American Business Programs

    Get PDF
    This essay presents an overview of what American business programs cover in their curricula regarding ethics and the reasons behind teaching ethics-related material to business students. Topics for the paperinclude; requirements for having ethics in the curricula, broad perspectives of what constitutes ethical business practices, and the difference between professional ethics and business ethics. Journal of Economic Literature (JEL) classification: M14, A2

    Professionalism and Ethics in Hospitality

    Get PDF
    In their discussion - Professionalism and Ethics in Hospitality - by James R. Keiser, Associate Professor and John Swinton, Instructor, Hotel, Restaurant and Institutional Management, The Pennsylvania State University, Keiser and Swinton initially offer: “Referring to “the hospitality profession” necessitates thinking of the ethics of that profession and how ethics can be taught. The authors discuss what it means for the hospitality industry to be a profession.” The authors will have you know, a cursory nod to the term or description, profession and/or professional, is awarded to the hospitality industry at large; at least in an academic sense. Keiser and Swinton also want you to know that ethics, and professionalism are distinctly unique concepts, however, they are related. Their intangible nature does make them difficult, at best, to define, but ethics in contemporary hospitality has, to some degree, been charted and quantified. “We have left the caveat emptor era, and the common law, the Uniform Commercial Code, and a variety of local ordinances now dictate that the goods and services hospitality offers carry an implied warranty of merchantability,” the authors inform you. About the symbiotic relationship between ethics and professionalism, the authors say this: The less precise a code of ethics goes, the general rule, the fewer claims the group has to professional status.” The statement above may be considered a cornerstone principle. “However, the mere existence of an ethical code (or of professional status, for that matter) does not ensure ethical behavior in any group,” caution Keiser and Swinton. “Codes of ethics do not really define professionalism except as they adopt a group\u27s special, arcane, exclusionary jargon. Worse, they can define the minimum, agreed-upon standards of conduct and thereby encourage ethical corner-cutting,” they further qualify the thought. And, in bridging academia, Keiser and Swinton say, “Equipped now with a sense of the ironies and ambiguities inherent in labeling any work professional, we can turn to the problem of instilling in students a sense of what is professionally ethical. Students appear to welcome this kind of instruction, and while we would like to think their interest comes welling up from altruism and intellectual curiosity rather than drifting down as Watergate and malpractice fallout, our job is to teach, not to weigh the motives that bring us our students, and to provide a climate conducive to ethical behavior, not supply a separate answer for every contingency.” Keiser and Swinton illustrate their treatise on ethics via the hypothetical tale [stylized case study] of Cosmo Cuisiner, who manages the Phoenix, a large suburban restaurant. Cosmo is “…a typical restaurant manager faced with a series of stylized, over-simplified, but illustrative decisions, each with its own ethical skew for the students to analyze.” A shortened version of that case study is presented. Figure 1 outlines the State Restaurant Association Code of Ethics

    Book Reviews

    Get PDF

    Quantifying biogenic bias in screening libraries.

    Get PDF
    In lead discovery, libraries of 10(6) molecules are screened for biological activity. Given the over 10(60) drug-like molecules thought possible, such screens might never succeed. The fact that they do, even occasionally, implies a biased selection of library molecules. We have developed a method to quantify the bias in screening libraries toward biogenic molecules. With this approach, we consider what is missing from screening libraries and how they can be optimized

    NAFTA/USMCA Dispute Settlement Mechanisms and the Constitution

    Get PDF

    Business Ethics and Ethics Education in American Business Programs

    Get PDF
    This essay presents an overview of what American business programs cover in their curricula regarding ethics and the reasons behind teaching ethics-related material to business students. Topics for the paper include; requirements for having ethics in the curricula, broad perspectives of what constitutes ethical business practices, and the difference between professional ethics and business ethics. Journal of Economic Literature (JEL) classification: M14, A2

    The Chemical Basis of Pharmacology

    Get PDF
    ABSTRACT: Molecular biology now dominates pharmacology so thoroughly that it is difficult to recall that only a generation ago the field was very different. To understand drug action today, we characterize the targets through which they act and new drug leads are discovered on the basis of target structure and function. Until the mid-1980s the information often flowed in reverse: investigators began with organic molecules and sought targets, relating receptors not by sequence or structure but by their ligands. Recently, investigators have returned to this chemical view of biology, bringing to it systematic and quantitative methods of relating targets by their ligands. This has allowed the discovery of new targets for established drugs, suggested the bases for their side effects, and predicted the molecular targets underlying phenotypic screens. The bases for these new methods, some of their successes and liabilities, and new opportunities for their use are described. So dominant has the molecular biology view of pharmacology become that it is difficult to remember that even 25 years ago it was little more than an aspiration. Today we understand the activity of drugs and reagents first through the specific, clonable receptor molecules with which they interact. To understan
    corecore