Carleton University

About: Carleton University is a education organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 15852 authors who have published 39650 publications receiving 1106610 citations.

Relative Power of the Wilcoxon Test, the Friedman Test, and Repeated-Measures ANOVA on Ranks

Abstract: Many introductory statistics textbooks in education, psychology, and the social sciences consider the Friedman test to be a nonparametric counterpart of repeated-measures ANOVA, just as the Kruskal-Wallis test is a counterpart of oneway ANOVA However, it is known in theoretical statistics that the Friedman test is a generalization of the sign test and possesses the modest statistical power of the sign test for normal as well as many nonnormal distributions Although not familiar to researchers, another significance test that can be regarded as a nonparametric counterpart of repeated-measures ANOVA is a rank-transformation procedure, in which the usual parametric statistical analysis is performed on ranks replacing the original scores In the present computer simulation study we compared the ordinary paired-samples Student t test, the Wilcoxon signed-ranks test, and the sign test for correlated samples from normal, uniform, mixed-normal, exponential, Laplace, and Cauchy distributions, for which t

Effect of inescapable shock on subsequent escape performance: catecholaminergic and cholinergic mediation of response initiation and maintenance.

Abstract: Following exposure to inescapable shock, subsequent escape performance is disrupted if the task is one in which animals receive forced exposure to shock for several seconds before escape is possible. The extent of the deficit is directly related to the severity of the initial stress and the duration of escape delay used during test. Treatment with a tyrosine hydroxylase inhibitor, α-methyl-p-tyrosine (α-MpT), a dopamine-β-hydroxylase inhibitor, FLA-63, or dopamine antagonists, haloperidol, and pimozide, mimicked the effects of inescapable shock in the different escape paradigms. The effects of haloperidol were antagonized by treatment with scopolamine. As observed in the case of inescapable shock, prior escape training abated the disruptive effects of the drug treatments. Finally, decreasing or blocking catecholamine activity or increasing cholinergic activity exacerbated the effect of a moderate amount of inescapable shock on subsequent escape performance. These treatments also induced reductions in shock-elicited activity. Conversely, treatment with a catecholamine stimulant, l-dopa, or a cholinergic blocker, scopolamine, anatagonized the reduction in shock-elicited activity and the escape deficits engendered by prior inescapable shock. It was hypothesized that both DA and NE, as well as ACh, are involved in the escape deficit observed after inescapable shock, and that these transmitters mediate the interference by their influence on response initiation and maintenance, rather than on associative or cognitive processes.

Endocrine and cytokine correlates of major depression and dysthymia with typical or atypical features

Abstract: Depression has been associated with both suppression and enhancement of various aspects of immune functioning. It was of interest to determine whether cytokine alterations associated with depression, including interleukin-1 (IL-1β) and interleukin-2 (IL-2), were related to the neurovegetative symptom profile or to the chronicity of the illness. Circulating ACTH, cortisol, norepinephrine (NE) and epinephrine levels, and production of IL-1β and IL-2 from mitogen-stimulated lymphocytes were assessed in classical major depression, atypical depression (ie, with reversed neurovegetative features), and dysthymia (chronic depression without comorbid major depression) with either typical or atypical profiles, as well as nondepressed control subjects. Among atypical depressives, plasma ACTH levels were elevated while cortisol was reduced relative to controls. Irrespective of neurovegetative profile, IL-1β production was increased in dysthymic patients, and was highly correlated with age-of-onset and duration of illness. In contrast, IL-2 production was reduced in each of the groups, although less so among atypical major depressives. Moreover, IL-2 production in the depressive groups was directly related to plasma NE levels. While neither depressed mood per se nor neurovegetative features accounted for this effect, it seemed likely that chronicity of illness or age-of-onset were associated with cytokine alterations. Given that circulating cytokines influence neuroendocrine functioning, and may affect neurovegetative features, a role for interleukins may exist with respect to the pathophysiology of certain subtypes of depression.

Evolution of the hind wing in coleoptera

Abstract: A survey is made of the major features of the venation, articulation, and folding in the hind wings of Coleoptera. The documentation is based upon examination of 108 Coleoptera families and 200 specimens, and shown in 101 published figures. Wing veins and articular sclerites are homologized with elements of the neopteran wing groundplan, resulting in wing vein terminology that differs substantially from that generally used by coleopterists. We tabulate the differences between currently used venational nomenclature and the all-pterygote homologous symbols. The use of the neopteran groundplan, combined with the knowledge of the way in which veins evolved, provides many strong characters linked to the early evolutionary radiation of Coleoptera. The order originated with the development of the apical folding of the hind wings under the elytra executed by the radial and medial loop. The loops, which are very complex venational structures, further diversified in four distinctly different ways which mark the highest (suborder) taxa. The remaining venation and the wing articulation have changed with the loops, which formed additional synapomorphies and autapomorphies at the suborder, superfamily, and sometimes even family and tribe levels. Relationships among the four currently recognized suborders of Coleoptera are reexamined using hind wing characters. The number of wing-related apomorphies are 16 in Coleoptera, seven in Archostemata + Adephaga–Myxophaga, four in Adephaga–Myxophaga, seven in Myxophaga, nine in Archostemata, and five in Polyphaga. The following phylogenetic scheme is suggested: Polyphaga [Archostemata (Adephaga + Myxophaga)]. Venational evidence is given to define two major lineages (the hydrophiloid and the eucinetoid) within the suborder Polyphaga. The unique apical wing folding mechanism of beetles is described. Derived types of wing folding are discussed, based mainly on a survey of recent literature. A sister group relationship between Coleoptera and Strepsiptera is supported by hind wing evidence.