Biplots of compositional data

The singular value decomposition and its interpretation as a linear biplot has proved to be a powerful tool for analysing many forms of multivariate data. Here we adapt biplot methodology to the speciffic case of compositional data consisting of positive vectors each of which is constrained to have unit sum. These relative variation biplots have properties relating to special features of compositional data: the study of ratios, subcompositions and models of compositional relationships. The methodology is demonstrated on a data set consisting of six-part colour compositions in 22 abstract paintings, showing how the singular value decomposition can achieve an accurate biplot of the colour ratios and how possible models interrelating the colours can be diagnosed.Logratio transformation, principal component analysis, relative variation biplot, singular value decomposition, subcomposition

La distància de l'eixample

Inspirándonos en el diseño del Ensanche de Barcelona de Ildefonso Cerdá, definimos una nueva distancia estadística, denominada la distancia del ensanche. Se estudian algunas propiedades de esta función de distancia y se proponen algunas posibles aplicaciones

Diffuse intestinal T-cell lymphosarcoma in a yellow-naped Amazon parrot (Amazona ochrocephala auropalliata)

A 10-year-old, intact, female yellow-naped Amazon parrot was examined because of anemia, lymphocytic leukocytosis, regurgitation, and weight loss. A positive fecal occult blood and monoclonal globulinopathy were present. A distended proventriculus and diffusely thickened loops of small intestine with irregular luminal surfaces were identified with contrast radiography and contrast computed tomography. A micro positron emission tomography scan was performed with (18)F-fluorodeoxyglucose. Diffuse intestinal T-cell lymphosarcoma was diagnosed based on histopathology and immunohistochemistry of full thickness small intestinal biopsies. The patient was treated with a multidrug chemotherapy protocol with little to no effect. Euthanasia was elected, and intestinal lymphosarcoma was confirmed on histopathology of necropsy intestinal samples; no other organs demonstrated neoplastic infiltration. To the authors\u27 knowledge, no reports are currently available detailing the clinical presentation or diagnosis of diffuse intestinal T-cell lymphosarcoma in any avian species

A Comparison of U. S. and European University-Industry Relations in the Life Sciences

We draw on diverse data sets to compare the institutional organization of upstream life science research across the United States and Europe. Understanding cross-national differences in the organization of innovative labor in the life sciences requires attention to the structure and evolution of biomedical networks involving public research organizations (universities, government laboratories, nonprofit research institutes, and research hospitals), science-based biotechnology firms, and multinational pharmaceutical corporations. We use network visualization methods and correspondence analyses to demonstrate that innovative research in biomedicine has its origins in regional clusters in the United States and in European nations. But the scientific and organizational composition of these regions varies in consequential ways. In the United States, public research organizations and small firms conduct R&D across multiple therapeutic areas and stages of the development process. Ties within and across these regions link small firms and diverse public institutions, contributing to the development of a robust national network. In contrast, the European story is one of regional specialization with a less diverse group of public research organizations working in a smaller number of therapeutic areas. European institutes develop local connections to small firms working on similar scientific problems, while cross-national linkages of European regional clusters typically involve large pharmaceutical corporations. We show that the roles of large and small firms differ in the United States and Europe, arguing that the greater heterogeneity of the U. S. system is based on much closer integration of basic science and clinical development

eBay users form stable groups of common interest

Market segmentation of an online auction site is studied by analyzing the users' bidding behavior. The distribution of user activity is investigated and a network of bidders connected by common interest in individual articles is constructed. The network's cluster structure corresponds to the main user groups according to common interest, exhibiting hierarchy and overlap. Key feature of the analysis is its independence of any similarity measure between the articles offered on eBay, as such a measure would only introduce bias in the analysis. Results are compared to null models based on random networks and clusters are validated and interpreted using the taxonomic classifications of eBay categories. We find clear-cut and coherent interest profiles for the bidders in each cluster. The interest profiles of bidder groups are compared to the classification of articles actually bought by these users during the time span 6-9 months after the initial grouping. The interest profiles discovered remain stable, indicating typical interest profiles in society. Our results show how network theory can be applied successfully to problems of market segmentation and sociological milieu studies with sparse, high dimensional data.Comment: Major revision of the manuscript. Methodological improvements and inclusion of analysis of temporal development of user interests. 19 pages, 12 figures, 5 table

Hydrochlorination of ruthenaphosphaalkenyls: unexpectedly facile access to alkylchlorohydrophosphane complexes

The novel ruthenaphosphaalkenyls [Ru{P═C(H)SiMe2R}Cl- (CO)(PPh3)2] (R = p-C6H4CF3, nBu) have been prepared for the first time, and studied alongside precedent analogues (R = Me, Ph, p-tol) for their reactions with HCl. In contrast to chemistry defined for the tert-butyl congener [Ru{P═C(H)tBu}Cl(CO)(PPh3)2], which initially adds a single equivalent of HCl across the Ru−P linkage, all five silyl derivatives undergo spontaneous addition of a second equivalent to afford [Ru{η1-PHCl−CH2SiMe2R}Cl(CO)(PPh3)2], extremely rare examples of coordinated “PHXR” type ligands. Where R = SiMe3, a distorted octahedral geometry with a conformationally restricted “PHXR” ligand is observed crystallographically; this structure is appreciably retained in solution, as determined from multinuclear NMR spectroscopic features, which include a Karplus-like PPh3−Ru−P−H spin−spin coupling dependence. Computational data suggest a silyl-induced increase in negative charge density at the phosphaalkenic carbon, rather than an intrinsic thermodynamic driver, as the likely origin of the disparate reactivity

Factors Affecting Synonymous Codon Usage Bias in Chloroplast Genome of Oncidium Gower Ramsey

Oncidium Gower Ramsey is a fascinating and important ornamental flower in floral industry. In this research, the complete nucleotide sequence of the chloroplast genome in Oncidium Gower Ramsey was studied, then analyzed using Codonw software. Correspondence analysis and method of effective number of codon as Nc-plot were conducted to analyze synonymous codon usage. According to the corresponding analysis, codon bias in the chloroplast genome of Oncidium Gower Ramsey is related to their gene length, mutation bias, gene hydropathy level of each protein, gene function and selection or gene expression only subtly affect codon usage. This study will provide insights into the molecular evolution study and high-level transgene expression

Risk of Congenital Anomalies after the Opening of Landfill Sites

Concern that living near a particular landfill site in Wales caused increased risk of births with congenital malformations led us to examine whether residents living close to 24 landfill sites in Wales experienced increased rates of congenital anomalies after the landfills opened compared with before they opened. We carried out a small-area study in which expected rates of congenital anomalies in births to mothers living within 2 km of the sites, before and after opening of the sites, were estimated from a logistic regression model fitted to all births in residents living at least 4 km away from these sites and hence not likely to be subject to contamination from a landfill, adjusting for hospital catchment area, year of birth, sex, maternal age, and socioeconomic deprivation score. We investigated all births from 1983 through 1997 with at least one recorded congenital anomaly [International Classification of Diseases, Ninth Revision (ICD-9), codes 7400–7599; International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10), codes Q000–Q999]. The ratio of the observed to expected rates of congenital anomalies before landfills opened was 0.87 [95% confidence interval (CI), 0.75–1.00], and this increased to 1.21 (95% CI, 1.04–1.40) after opening, giving a standardized risk ratio of 1.39 (95% CI, 1.12–1.72). Enhanced congenital malformation surveillance data collected from 1998 through 2000 showed a standardized risk ratio of 1.04 (95% CI, 0.88–1.21). Causal inferences are difficult because of possible biases from incomplete case ascertainment, lack of data on individual-level exposures, and other socioeconomic and lifestyle factors that may confound a relationship with area of residence. However, the increase in risk after the sites opened requires continued enhanced surveillance of congenital anomalies, and site-specific chemical exposure studies