1,574 research outputs found
Urban and Peri-urban Agriculture in Kyiv (Ukraine): "Crisis Induced Strategy" versus Recreational Resource
No full textFor the study 240 Kyiv households with urban and peri-urban agriculture (UPA) have been surveyed in 2005. Quotas were assigned to four different types of plots. A standardized questionnaire was developed to collect data on crop and animal production, inputs, sales of produce for income, importance of the plot for self-sufficiency, recreation and leisure time. A factor analysis is employed to reduce attitudinal data. Based on factor scores a cluster analysis is conducted to segment the respondents into more homogeneous groups and to show multiple purposes of UPA. Four clusters labeled as “Seekers of leisure activities”, “UPA-dependent growers”, “Recreation-oriented growers” and “Little engaged growers” are created. Multiple purposes of UPA are shown by profiling the clusters due to demographic, socioeconomic and other selected characteristics. The results show that depending on the type of plot the importance of UPA shifts from livelihood necessity to recreational resource or combines both.Urban and peri-urban agriculture, livelihood, Ukraine, Farm Management,
Hyperplane sections of convex bodies
No full textWe prove sharp inequalities for the volumes of hyperplane sections bisecting a convex body in R^n. This leads to a relative isoperimetric inequality for arbitrary hyperplane sections of a convex body
On the geometric structure of lattice U-polygons
No full textAbstractLet U be a finite set of directions in the Euclidean plane. A convex polygon P is a U-polygon if for each vertex v of P and for each u∈U the line with direction u through v meets a vertex of P different from v. We study the geometric structure of lattice U-polygons and introduce the notion of class of a U-polygon. We then characterize the lattice U-polygons of class c⩾4. On the other hand, if P is a lattice U-polygon of class c<4, we describe a few geometric properties of P
Discrete tomography for inscribable lattice sets
No full textIn this paper we deal with uniqueness and reconstruction problems in Discrete Tomography. For a finite set of directions in , we introduce the class of -inscribable lattice sets, and give a detailed description of their geometric structure. This shows that such sets can be considered as the natural discrete counterpart of the same notion known in the continuous case, as well as a kind of generalization of the class of the so called -convex polyominoes (or moon polyominoes). In view of reconstruction from projections along the directions in , two related questions of tomographic interest are investigated, namely uniqueness and additivity. We show that both properties are fulfilled by -inscribable lattice sets. Moreover,
concerning the case , we provide an explicit reconstruction algorithm from the knowledge of directed horizontal and vertical -rays, jointly with a few preliminary results towards a possible sharp stability inequality
Discrete Tomography and plane partitions
No full textA \textit{plane partition} is a matrix , where and , with non-negative integer entries, and whose rows and columns are weakly decreasing. From a geometric point of view plane partitions are equivalent to \textit{pyramids}, subsets of the integer lattice which play an important role in Discrete Tomography. As a consequence, some typical problems concerning the tomography of discrete lattice sets can be rephrased and considered via plane partitions. In this paper we focus on some of them. In particular, we get a necessary and sufficient condition for additivity, a canonical procedure for checking the existence of (weakly) bad configurations, and an algorithm which constructs "minimal" pyramids with assigned projection of a bad configurations
On J-additivity and bounded additivity
No full textIn this paper we consider the uniqueness issues in Discrete Tomography. A special class of geometric objects, widely considered in the literature, is represented by additive sets. These sets are uniquely determined by their X-rays, and they are also reconstructible in polynomial time by use of linear programming. Recently, additivity has been extended to J-additivity to provide a more general treatment of known concepts and results. A further generalization of additivity, called bounded additivity is obtained by restricting to sets contained in a given orthogonal box. In this work, we investigate these two generalizations from a geometrical point of view and analyze the interplay between them
Indicadores de risco para a peri-implantite
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Programa de Pós-Graduação em Odontologia, Florianópolis, 2014.O objetivo deste estudo foi identificar os indicadores de risco sistêmicos e locais associados com a peri-implantite e sua prevalência. Os critérios de inclusão para o estudo compreenderam: pacientes tratados com implantes de titânio Implacil De Bortoli (São Paulo, Brasil) na Fundação para o Desenvolvimento Científico e Tecnológico da Odontologia (FUNDECTO), da Universidade de São Paulo (USP), no período de 1998 a 2012. Foram examinados 183 pacientes, reabilitados com 916 implantes em função por pelo menos 1 ano. As variáveis foram avaliadas segundo condição sistêmica do paciente, características do implante, coroa protética e parâmetros clínicos. A regressão logística não demonstrou associação de características do implante com a PI. Houve correlação estatística positiva para histórico de doença periodontal (DP), próteses cimentadas, presença de facetas de desgaste na coroa protética e próteses totais. A PI apresentou risco aumentado em 2.20 vezes para histórico de DP, 3.62 vezes para próteses cimentadas em relação às parafusadas, 2.43 vezes na presença de facetas de desgaste na coroa protética e 16.11 vezes para próteses totais em relação as parafusadas. Foram relacionados como indicadores de risco para a PI histórico de DP, próteses cimentadas, presença de facetas de desgaste na coroa protética e próteses totais. As características dos implantes não foram relacionadas com a PI.Abstract : The aim of this study was to identify systemic and local risk indicators associated with peri-implantitis (PI) and its prevalence. Inclusion criteria for the study were patients treated with osseointegrated implants (Implacil De Bortoli, Sao Paulo, Brazil) at FUNDECTO (University of Sao Paulo, USP), from 1998 to 2012. There were examined 183 patients, rehabilitated with 916 implants in function for 1 year at least. Variables were evaluated according to patient's systemic condition, implant's characteristics, prosthetic crown and clinical parameters. Logistic regression did not show any association between implant's characteristics with PI. Also, it was identified an increased risk of 2.20 times for historic of periodontal disease (PD), 3.62 times for cemented restorations compared to screw-retained, 2.43 times when displayed wear facets on the prosthetic crown and 16.11 times for total rehabilitations when compared to single rehabilitations. There were related as risk indicators for PI the historic of periodontal disease, cemented prostheses, presence of wear facets on the prosthetic crown and in total rehabilitations. Implants' characteristics were not related with PI
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