Multidimensional scaling of D15 caps: Color-vision defects among tobacco smokers?

Tobacco smoke contains a range of toxins including carbon monoxide and cyanide. With specialized cells and high metabolic demands, the optic nerve and retina are vulnerable to toxic exposure. We examined the possible effects of smoking on color vision: specifically, whether smokers perceive a different pattern of suprathreshold color dissimilarities from nonsmokers. It is already known that smokers differ in threshold color discrimination, with elevated scores on the Roth 28-Hue Desaturated panel test. Groups of smokers and nonsmokers, matched for sex and age, followed a triadic procedure to compare dissimilarities among 32 pigmented stimuli (the caps of the saturated and desaturated versions of the D15 panel test). Multidimensional scaling was applied to quantify individual variations in the salience of the axes of color space. Despite the briefness, simplicity, and “low-tech” nature of the procedure, subtle but statistically significant differences did emerge: on average the smoking group were significantly less sensitive to red–green differences. This is consistent with some form of injury to the optic nerve

Reactor power systems for manned earth orbital applications

Design requirements for reactor power system of manned earth orbital space statio

An Engineered Nonsense \u3cem\u3eURA3\u3c/em\u3e Allele Provides a Versatile System to Detect the Presence, Absence and Appearance of the [em\u3ePSI\u3c/em\u3e\u3csup\u3e+\u3c/sup\u3e] Prion in \u3cem\u3eSaccharomyces cerevisiae\u3c/em\u3e

Common methods to identify yeast cells containing the prion form of the Sup35 translation termination factor, [PSI+], involve a nonsense suppressor phenotype. Decreased function of Sup35p in [PSI+] cells leads to readthrough of certain nonsense mutations in a few auxotrophic markers, for example, ade1-14. This readthrough results in growth on adenine deficient media. While this powerful tool has dramatically facilitated the study of [PSI+], it is limited to a narrow range of laboratory strains and cannot easily be used to screen for cells that have lost the [PSI+] prion. Therefore we have engineered a nonsense mutation in the widely used URA3 gene, termed the ura3-14 allele. Introduction of the ura3-14 allele into an array of genetic backgrounds, carrying a loss-of-function URA3 mutation and [PSI+], allows for growth on media lacking uracil, indicative of decreased translational termination efficiency. This ura3-14 allele is able to distinguish various forms of the [PSI+] prion, called variants and is able to detect the de novo appearance of [PSI+] in strains carrying the prion form of Rnq1p, [PIN+]. Furthermore, 5-fluoorotic acid, which kills cells making functional Ura3p, provides a means to select for [psi−] derivatives in a population of [PSI+] cells marked with the ura3-14 allele, making this system much more versatile than previous methods

Feminist Aims and A Trans-Inclusive Definition of Woman

Katharine Jenkins argues that Sally Haslanger’s focal analysis of gender problematically excludes non-passing trans women from the category “woman.” However, Jenkins does not explain why this exclusion contradicts the feminist aims of Haslanger’s account. In this paper, I advance two arguments that suggest that a trans-inclusive account of “woman” is crucial to the aims of feminism. I claim that the aims of feminism are to understand and combat women’s oppression. First, I argue that denial of trans identities reinforces cultural ideas that perpetuate both transphobic violence and sexual violence against women. Consequently, a feminist account of “woman” that fails to respect trans identities indirectly contributes to the oppression of women. Second, I prove that non-passing trans women are oppressed as women through the internalization of sexual objectification. I then conclude that an account of “woman” that excludes non-passing trans women cannot successfully advance a complete understanding of women’s oppression

What\u27s Current in Asbestos Regulations

Asbestos, once valued as a superb insulator, is now recognized as a deadly carcinogen. The United States Environmental Protection Agency ( EPA ) estimates that 733,000 public and commercial buildings in the United States contain friable asbestos or asbestos-containing materials. Thus, it is not surprising that an avalanche of litigation has resulted from concerns over exposure to asbestos

Ecology of \u3cem\u3eAroga websteri\u3c/em\u3e Clarke in Curlew Valley, Utah-Idaho

The ecology, life history, and population dynamics of the sagebrush defoliator, Aroga websteri Clarke, were studied in the field and laboratory. The defoliator has one generation a year at the Curlew Valley site. It overwintered in the egg stage and passed through five larval instars. Ten parasite species attacked the defoliator at the study site . Four species, Orgilus ferus, Phaeogenes sp., Spilochalcis leptis, and Apanteles cacoeciae, contributed over 75 percent of the total incidence of parasitism. Parasitism ranged from 20 to 76 percent in 1971, but only ranged from 6 to 29 percent in 1972. This decrease in total parasitism in 1972 coincided with a five-fold increase in the defoliator population. In 1972, many mature larvae died as a result of food shortage. A microsporidian infection and a predaceous beetle also caused variable mortality during the two years. Methods for determining defoliation to sagebrush plants were also studied in the field. The consumption and utilization of food by the fourth and fifth larval instars were determined. The fecundity, rate of development, and behavior of the insect were also investigated under laboratory conditions. Partial life tables were constructed from the findings of 1971 and 1972 to assess the r ole of various mortality factors in regulating the sagebrush defoliator numbers

Inlet spillage drag tests and numerical flow-field analysis at subsonic and transonic speeds of a 1/8-scale, two-dimensional, external-compression, variable-geometry, supersonic inlet configuration

Accurate spillage drag and pressure data are presented for a realistic supersonic inlet configuration. Results are compared with predictions from a finite-differencing, inviscid analysis computer procedure. The analytical technique shows good promise for the evaluation of inlet drag, but necessary refinements were identified. A detailed description of the analytical procedure is contained in the Appendix

Federal and State Remedies to Clean Up Hazardous Waste Sites

Over fifty-seven million metric tons of hazardous waste are produced as a by-product of manufacturing in the United States each year. Only ten percent of this waste is disposed of in an environmentally sound manner. The improper disposal of hazardous waste has given rise to crisis areas of national notoriety such as Love Canal and Valley of the Drums. Although the danger to public health and the environment cannot be precisely calculated, the disposal of hazardous waste presents a problem that can no longer be ignored. Virginia\u27s own experience with kepone contamination in the James River exemplifies the dangers and costs associated with this disposal problem

Bounds on the subdominant eigenvalue involving group inverses with applications to graphs

summary:Let $A$ be an $n\times n$ symmetric, irreducible, and nonnegative matrix whose eigenvalues are $\lambda _1 > \lambda _2 \ge \ldots \ge \lambda _n$. In this paper we derive several lower and upper bounds, in particular on $\lambda _2$ and $\lambda _n$, but also, indirectly, on $\mu = \max _{2\le i \le n} |\lambda _i|$. The bounds are in terms of the diagonal entries of the group generalized inverse, $Q^{\#}$, of the singular and irreducible M-matrix $Q=\lambda _1 I-A$. Our starting point is a spectral resolution for $Q^{\#}$. We consider the case of equality in some of these inequalities and we apply our results to the algebraic connectivity of undirected graphs, where now $Q$ becomes $L$, the Laplacian of the graph. In case the graph is a tree we find a graph-theoretic interpretation for the entries of $L^{\#}$ and we also sharpen an upper bound on the algebraic connectivity of a tree, which is due to Fiedler and which involves only the diagonal entries of $L$, by exploiting the diagonal entries of $L^{\#}$