1,582 research outputs found
Transformations Groups of the Andersson-Perlman Cone
No full text. An Andersson-Perlman cone is a certain subcone\Omega\Gamma K) of the symmetric cone\Omega of a Euclidean Jordan algebra. We exhibit a subgroup of the automorphism group of\Omega which operates transitively on \Omega\Gamma K) and show that \Omega\Gamma K) is a simply-connected submanifold of\Omega . 1. Introduction. Andersson-Perlman cones in the setting of Euclidean Jordan algebras (henceforth abbreviated as AP cones) were introduced by H. Massam and the author in [MN] as a generalization of certain cones defined by the statisticians S. A. Andersson and M. D. Perlman for real symmetric matrices [AP]. All mathematical results in [AP] were generalized in [MN] to the setting of Euclidean Jordan algebras, except the existence of transitive transformation groups which play a predominant role in the development in [AP]. In fact, the paper [MN] stresses a different, perhaps more direct approach to the description of Andersson-Perlman cones by employing Peirce decompositions and Frobeniu..
On the Power of the Noncentral F- and Wilks' U-Tests: Choosing Variates for Increasing the Power of Hotelling's T2-Test
No full text1 online resource (PDF, 29 pages)Gupta, Somesh Das; Perlman, Michael D.. (1972). On the Power of the Noncentral F- and Wilks' U-Tests: Choosing Variates for Increasing the Power of Hotelling's T2-Test. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/199161
Massive Cellular Angiofibroma of the Vulva
No full textCellular angiofibromas of the vulva are uncommon, and usually small and circumscribed. A massive cellular angiofibroma extending into the pelvis is described.Peer reviewe
Report on the International Public Management Network Research Conference in Rio de Janeiro, Brazil
No full textThe paper reports on the 2004 Conference of the International Public Management Network "Third Generation Reform in Brazil and Other Nations: Achieving Governmental, Social and Economic Realignment" . The author, a rapporteur at that Conference, offers his view about the critical elements presented by the different speakers, and recaps some suggestions aimed at ensuring a higher success of reform of whatever generation
The Impact of Tidal Disruption Events on Galactic Habitability
No full textTidal Disruption Events (TDEs) are characterized by the emission of a short
burst of high-energy radiation. We analyze the cumulative impact of TDEs on
galactic habitability using the Milky Way as a proxy. We show that X-rays and
extreme ultraviolet (XUV) radiation emitted during TDEs can cause hydrodynamic
escape and instigate biological damage. By taking the appropriate variables
into consideration, such as the efficiency of atmospheric escape and distance
from the Galactic center, we demonstrate that the impact of TDEs on galactic
habitability is comparable to that of Active Galactic Nuclei. In particular, we
show that planets within distances of - kpc could lose Earth-like
atmospheres over the age of the Earth, and that some of them might be subject
to biological damage once every yrs. We conclude by highlighting
potential ramifications of TDEs and argue that they should be factored into
future analyses of inner galactic habitability.Comment: MNRAS, in pres
Investigating the Role of DIS3L2 in Perlman Syndrome and Wilms Tumor
No full textThe general metadata -- e.g., title, author, abstract, subject headings, etc. -- is publicly available, but access to the submitted files is restricted to UT Southwestern campus access and/or authorized UT Southwestern users.Wilms tumor, while the most common pediatric kidney tumor, has a poorly understood etiology. Several recent studies have uncovered a role for loss of let-7 in its pathogenesis. One crucial mechanism through which let-7 expression is controlled is via the activity of the RNA-binding protein LIN28, which binds the precursor of let-7 and mediates the addition of a series of uridines to the 3′ end. This oligouridylation marks pre-let-7 for degradation by the exoribonuclease DIS3L2. Loss-of-function mutations in DIS3L2 lead to the Perlman congenital overgrowth syndrome, characterized by high neonatal mortality and, interestingly, a strong predisposition to Wilms tumor. Furthermore, DIS3L2 has been found to be deleted or mutated in some cases of sporadic Wilms tumor. The importance of let-7 in Wilms tumorigenesis and a purported role for DIS3L2 in the LIN28-let-7 pathway have led to speculation that aberrant let-7 expression underlies Wilms tumor susceptibility in DIS3L2-deficient contexts.
It is still unclear, though, how loss of DIS3L2 could lead to altered let-7 levels, as the uridylated pre-let-7 species that DIS3L2 degrades is believed to be a dead-end product that cannot be further processed by DICER into mature let-7. Thus far, regulation of mature let-7 levels by DIS3L2 has only been examined in a limited number of cell lines. To determine whether DIS3L2 regulation of let-7 differs in a broader set of cell types, we used genome-editing to knockout DIS3L2 in a wide-ranging panel of cell lines with differing levels of LIN28 expression. Consistent with prior reports, loss of DIS3L2 had no effect on mature let-7 expression in these cell lines.
However, it remained possible that the regulation of let-7 by DIS3L2 differed in cell populations relevant to Wilms tumor pathogenesis in vivo. Thus, to examine DIS3L2 function in these contexts, we used CRISPR-Cas9 to generate mouse lines harboring either Dis3l2-null alleles or mutations commonly observed in Perlman syndrome. Interestingly, Dis3l2 mutants recapitulated some aspects of Perlman syndrome, including neonatal mortality and genitourinary abnormalities, but not overgrowth or Wilms tumor. Moreover, the phenotype that results from the most common Perlman mutation is the same as that seen in the Dis3l2 loss-of-function mouse model, suggesting that the DIS3L2 mutations reported in Perlman syndrome are indeed loss-of-function.
Finally, we examined the molecular function of DIS3L2 in isolated primary nephron progenitor cells (NPCs), a likely cell of origin of Wilms tumors, from Dis3l2-null and wild-type embryos. Consistent with our findings in the cell lines, loss of DIS3L2 in NPCs does not affect let-7 expression or activity, yet leads to upregulation of Igf2, which is reported to be overexpressed in 70-80% of Wilms tumors. Therefore, Igf2 poses an attractive candidate for both overgrowth and oncogenesis associated with DIS3L2 loss
The impact of AGN outflows on the surface habitability of terrestrial planets in the Milky Way
No full textThe Impact of tidal disruption events on galactic habitability
No full textTidal disruption events (TDEs) are characterized by the emission of a short burst of high-energy radiation. We analyse the cumulative impact of TDEs on galactic habitability using the Milky Way as a proxy. We show that X-rays and extreme ultraviolet radiation emitted during TDEs can cause hydrodynamic escape and instigate biological damage. By taking the appropriate variables into consideration, such as the efficiency of atmospheric escape and distance from the Galactic centre, we demonstrate that the impact of TDEs on galactic habitability is comparable to that of active galactic nuclei. In particular, we show that planets within distances of similar to 0.1-1 kpc could lose Earth-like atmospheres over the age of the Earth, and that some of them might be subject to biological damage once every greater than or similar to 10(4) yr. We conclude by highlighting potential ramifications of TDEs and argue that they should be factored into future analyses of inner galactic habitability
La théorie de Selig Perlman : une étude critique
No full textL'auteur analyse du point de vue méthodologique et du point de vue substantif la thèse exposée par Selig Perlman dans« A Theory of the Labor Movement ». Il en examine la consistance intrinsèque, l’utilité et les faiblesses. Il conclut que la théorie de Perlman est fondamentalement une apologie anti-marxiste dirigée principalement contre des propositions de Lénine. Une telle approche apporte une conception incomplète et normative du phénomène syndical. C'est pourquoi la thèse de Perlman demeure au niveau de généralisations dont l’utilité est limitée. En effet, considérant la base de la solidarité, les buts, les méthodes et les comportements syndicaux, elle ne fournit qu'une explication partielle, parfois subjective, des diverses composantes de faction syndicale.In this article, the author provides a systematic and detailed analysis of the theory of Selig Perlman, and submits it to a critical evaluation, both in terms of methodology and substance. The following is a brief outline of Perlman's approach.In his methodology, Perlman relies on three analytical elements: 1) three factors: the Power of subsistence of the capitalist system, the degree of influence of intellectuals upon organized labor, the level of maturity of the working class;2) three characteristics: the strength of the institution of private ownership, the degree of class consciousness among labor, the inadequacy of political tools;3) the psychology of manual labor.The essence of Perlman's theory may be outlined in the following manner. At the basis of labor solidarity is « the consciousness of scarcity of opportunity ». This explains why the role of trade unions is to control job opportunities; « job control » is based on « job interests ». For this purpose economic action, through collective agreements and strikes, appears to be the most effective approach. Political action may play, at best, a supplementary role. This approach is bound to lead to equality in industrial relations and to democratization in the economic structure; this may be attained without going through class warfare and without introducing a socialist or a communist system.A critical analysis of Perlman's theory brings out a number of points of methodological character:a) Essentially, the theory is an anti-Marxist apology of the stability of the capitalist system, mainly directed against the position of Lenin. At the basis of the divergence between Perlman and Lenin is the different evaluation of the role of the « intelligentsia ».b) Despite Perlman's claim to the contrary, he provides only a partial definition of trade unionism. This definition presents a scheme for a specific functional model; only through extension by means of a normative projection it becomes a general model for a true trade unionism.c) The analytical variables are not independent one from another, and because of this their interrelation cannot be significant. The three factors are defined, in part, each one by means of the others. The three characteristics are a descriptive elaboration of the three factors within the American context. Psychological categories are implicit in the definition of the third factor.d) The depreciatory concept of the « intelligentsia » reflects a subjective and biased approach to the problem of leadership in trade unionism. According to Perlman's definition, leaders who rose from the ranks of labor represent the concept of a « stable and responsible » trade unionism; in contrast, intellectuals, that is, « educated non-manualists », who enter the labor world introduce with them radicalism and revolutionary program of action, or advocate political action within trade unionism, in terms of Perlman's definition.With regard to the substance of Perlman's theory, this writer suggests the following points for consideration:a) The psychological approach ( « the consciousness of scarcity of opportunities »), despite some inconsistencies in definition and despite the fact that it may be regarded as typical for a particular group only, provides room for some useful generalizations; yet these generalizations are of limited character and cannot lead to theoretical conclusions. They reflect one element in workers' motivation to join the union and to support its activities. This element, in itself, cannot explain the process of labor organization, nor the occupational and territorial differentiation in the degree of unionization. Moreover, its origin is in the assumption of a state of chronic underemployment — a condition which is least favorable to labor solidarity.b) The concept of « job control » is related exclusively to occupational goals.c) Perlman sees in the joint system of control the most advantageous alternative; in his view, the autonomous system of control has no advantages, and control by external factors has an entirely secondary significance. By emphasizing collective negotiations he grossly underrestimates the importance of various forms of mutual assistance. Also, Perlman was not able, unfortunately, to provide a clear distinction between political activities of non-occupational character (revolutionary and other) and the utilization of political levers as a supplementary tool in realization of occupational and semi-occupational goals.d) The idealistic concept of « parity » in industrial relations cannot be ignored. Its eventual realization will call for a framework different from that provided by Perlman; under modem conditions the solution for existing problems often cannot be found on local level and has to rely on the dynamic intervention of a new interested party — the state
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