<p>This study examines the relationship between land fragmentation and agricultural productivity in Vietnam, as well as the outcomes of land consolidation programs on productivity. Data from the Vietnam Household Living Standard Survey 2004 and data on the land consolidation process was used for the regression analysis. The results show weak correlations between fragmentation and productivity. Land fragmentation seems to be positively correlated to productivity due to more use of fertilizers and labour input. The communes that have consolidated their land are more productive, but this seems to be explained by initial differences in productivity. Our results suggest that there are no immidiate gains in land consolidation.</p>

This study examines the relationship between land fragmentation and agricultural productivity in Vietnam, as well as the outcomes of land consolidation programs on productivity. Data from the Vietnam Household Living Standard Survey 2004 and data on the land consolidation process was used for the regression analysis. The results show weak correlations between fragmentation and productivity. Land fragmentation seems to be positively correlated to productivity due to more use of fertilizers and labour input. The communes that have consolidated their land are more productive, but this seems to be explained by initial differences in productivity. Our results suggest that there are no immidiate gains in land consolidation.

Submitted by (ana.araujo@ufrpe.br) on 2016-08-17T12:42:21Z No. of bitstreams: 1 Vanessa Kelly dos Santos.pdf: 364306 bytes, checksum: 6c79d0925f6821655f91bcd3c8eb64af (MD5) / Made available in DSpace on 2016-08-17T12:42:21Z (GMT). No. of bitstreams: 1 Vanessa Kelly dos Santos.pdf: 364306 bytes, checksum: 6c79d0925f6821655f91bcd3c8eb64af (MD5) Previous issue date: 2009-03-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Diversity as a concept was first introduced by Williams in Fisher et al. (1943). Later, Good (1953, 1982) proposed a generalized index that included as special cases both Shannon’s and Simpson’s indices. Baczkowski et al. (1997, 1998) generalized the proposed generalization deriving the first four moments and then obtaining a distribution prior to the general index for Good (BACZKOWSKI et al., 2000). Therefore, is proposed a new generalization that, in addition to the indices the Shannon and Simpson as special cases, includes more general indices such as the unfamiliar (PATIL & TAILIIE, 1982). The moments of h(a,b,d) presented here extend the results presented in Baczkowski et al. and Bowman et al. for a class of diversity indices of more general and it is concluded then that while the distribution of index Shannon can be approximated by a Gaussian distribution, if any difference between abundance of species, to more general values of (a,b,d), it is suggested a distribution of type I as the most appropriated. The results are also consistent with those presented for real populations, as in Heip & Engels (1974), especially when it examines the index of Shannon. / A diversidade como um conceito foi inicialmente introduzida por Williams em Fisher et al. (1943). Mais tarde, Good (1953, 1982) propôs um índice generalizado que incluía como casos especiais os índices de Shannon e o de Simpson. Baczkowski et al. (1997, 1998) propuseram generalizar essa generalização derivando os quatro primeiros momentos e obtendo assim uma distribuição para o índice antes generalizado por Good (BACZKOWSKI et al., 2000). Sendo assim, apresenta-se uma nova generalização que, além de ter os índices de Shannon e Simpson como casos especiais, engloba índices mais gerais como o não familiar (PATIL & TAILIIE, 1982). Os momentos de h(a,b,d) aqui apresentados estendem os resultados apresentados em Baczkowski et al. e Bowman et al. para uma classe de índices de diversidade mais geral, concluindo-se então que enquanto a distribuição do índice de Shannon pode ser aproximado por uma distribuição Gaussiana, caso haja diferença entre abundância de espécies, para valores mais gerais de (a,b,d), sugere-se uma distribuição do tipo I como sendo a mais apropriada. Os resultados obtidos são tão consistentes quanto os de trabalhos que lidam com populações reais como em Heip & Engels (1974), principalmente quando examina-se o índice de Shannon.

Submitted by Maria Aparecida (cidazen@gmail.com) on 2017-08-18T14:02:37Z No. of bitstreams: 1 cleriston.pdf: 1605933 bytes, checksum: c1faa5f854c1a9debfbaa1affc5ab4ad (MD5) / Made available in DSpace on 2017-08-18T14:02:37Z (GMT). No. of bitstreams: 1 cleriston.pdf: 1605933 bytes, checksum: c1faa5f854c1a9debfbaa1affc5ab4ad (MD5) Previous issue date: 2009-02-12 / The diagnosis of lung nodules has been constantly looked for by researchers as a way to minimize the high global mortality indices related to lung cancer. The usage of medical images, such as Computerized Tomography, has made possible the deepening and the improvement of techniques used to evaluate exams and provide diagnosis. This work presents a methodology for diagnosing single lung nodules that can be an aid for studies performed on similar areas and for specialists. This methodology was applied to two different image databases. The representation of the nodules was done with extraction of geometry and texture features, being the last one described through Simpson’s Index, a statistic used in Spatial Analysis and in Ecology. These features were submitted to the Support Vector Machine classifier (SVM) in two approaches: the traditional approach and the approach by using One Class. With the traditional SVM approach, we have obtained sensibility rates of 90%, specificity of 96.67% and accuracy of 95%. Using One Class SVM, the obtained rates were: sensibility of 89.7%, specificity of 89.7% and accuracy of 89.7%. / O diagnóstico de nódulos pulmonares tem sido buscado constantemente por pesquisadores como forma de amenizar os altos índices de mortalidade mundial relacionado ao câncer de pulmão. O uso de imagens médicas, como a Tomografia Computadorizada, tem possibilitado um aprofundamento e melhoramento de técnicas para avaliar exames e prover diagnósticos. Este trabalho apresenta uma metodologia para diagnóstico de nódulos pulmonares solitários que possa servir como um auxílio para estudos realizados em áreas afins e para especialistas. Esta metodologia foi aplicada a duas diferentes bases de dados de imagens. A representação dos nódulos foi feita com a extração de medidas de geometria e de textura sendo esta última descrita através do Índice de Simpson, uma estatística utilizada na Análise Espacial e na Ecologia. Essas medidas foram submetidas ao classificador Máquina de Vetores de Suporte - MVS em duas abordagens: a abordagem tradicional e abordagem usando uma classe. Com abordagem MVS tradicional, obtiveramse taxas de sensibilidade de 90%, especificidade de 96,67% e acurácia de 95%. Usando MVS de uma classe, as taxas obtidas foram: sensibilidade igual a 89,7%, especificidade igual a 89,7% e acurácia igual a 89,7%.