Use of Lorenz curves and Gini coefficients to assess yield inequality within paddocks

Sadras, Víctor O.; Bongiovanni, Rodolfo

doi:10.1016/j.fcr.2004.04.003

Cited by 86 publications

(39 citation statements)

References 21 publications

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“…The Gini coefficient is commonly used in economics and ecology to determine the degree to which some commodity is distributed among individuals (26) and is, as such, a direct measure of equality of distribution. For our purposes, we can use this approach to measure the equality of distribution for individual TCR clones in naïve and immune epitope-specific CTL populations.…”

Section: Resultsmentioning

confidence: 99%

Ecological analysis of antigen-specific CTL repertoires defines the relationship between naïve and immune T-cell populations

Thomas

Handel

Doherty

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Ecology is typically thought of as the study of interactions organisms have with each other and their environment and is focused on the distribution and abundance of organisms both within and between environments. On a molecular level, the capacity to probe analogous questions in the field of T-cell immunology is imperative as we acquire substantial datasets both on epitope-specific T-cell populations through high-resolution analyses of T-cell receptor (TCR) use and on global T-cell populations analyzed via high-throughput DNA sequencing. Here, we present the innovative application of existing statistical measures (used typically in the field of ecology), together with unique statistical analyses, to comprehensively assess how the naïve epitope-specific CD8 + cytotoxic T lymphocyte (CTL) repertoire translates to that found following an influenza-virus-specific immune response. Such interrogation of our extensive, cumulated TCR CDR3β sequence datasets, derived from both naïve and immune 114 , and influenza nonstructural protein 2 amino acid residues 114-121), demonstrates that epitope-specific TCR use in an antiviral immune response is the consequence of a complex interplay between the intrinsic characteristics of the naïve cytotoxic T lymphocyte precursor pool and extrinsic (likely antigen driven) influences, the contribution of which varies in an epitopespecific fashion.+ cytotoxic T lymphocytes (CTLs), the clonotypic T-cell receptor (TCR) recognizes "nonself" peptides (p) in complex with "self" class I MHC glycoproteins (MHCI). To recognize and respond to the vast array of novel pMHCI determinants encountered by a given individual (or population), the adaptive immune system uses the recombination of variable (V), junctional (J), diversity (D), and constant (C) somatic gene segments to establish an extraordinary spectrum of TCRs. Most of the observed TCR diversity results from imprecise joining of these gene segments and the addition of nontemplate-encoded nucleotides at V(D)J junctions (1). The consequence is that TCR diversity is principally a function of the CDR3 regions, meaning that clonal uniqueness is reliably defined by the TCRαβ CDR3 sequences.The nature of the highly specific TCR-pMHC recognition event likely determines functional outcomes after T-cell activation (2-6). Thus, the complexity and distribution of TCR use within a responding CTL population is likely to have a very real impact on the efficacy of T-cell-mediated pathogen clearance. Certainly, both virus control and the prevention of mutational escape operate more effectively if the host response is characterized by a diverse, rather than a limited, spectrum of pMHCI-specific TCRs (7-12). Further, TCR diversity has also been associated with effective cross-reactive immunity against different virus infections (13).Single cell RT-PCR analysis of CDR3 nucleotide sequences has provided an unprecedented level of resolution for characterizing TCR use, especially in the case of CTL responses to pathogens. Such detailed dissection of epitope-speci...

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Section: Resultsmentioning

confidence: 99%

Ecological analysis of antigen-specific CTL repertoires defines the relationship between naïve and immune T-cell populations

Thomas

Handel

Doherty

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…Taking these considerations into account, we use this approach. This concentration ratio is widely used in many fields of economics as well as in ecology and agronomics, but there are fewer applications in agricultural and environmental economics together Sadras and Bongiovanni, 2004;Seekell et al, 2011). In a general context, it ranges from zero (equal distribution) to one (perfect inequality).…”

Section: Measuring Rural Income Distributionmentioning

confidence: 99%

Climate change and drought effects on rural income distribution in the Mediterranean: a case study for Spain

Quiroga¹,

Suárez²

2016

Nat. Hazards Earth Syst. Sci.

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Abstract. This paper examines the effects of climate change and drought on agricultural incomes in Spanish rural areas. Present research has focused on the effects of these extreme climatological events through response functions, considering effects on crop productivity and average incomes. Among the impacts of droughts, we focused on potential effects on income distribution. The study of the effects on abnormally dry periods is therefore needed in order to perform an analysis of diverse social aspects in the long term. We estimate crop production functions for a range of Mediterranean crops in Spain and we use a measure of the decomposition of inequality to estimate the impact of climate change and drought on yield disparities. Certain adaptation measures may require a better understanding of risks by the public to achieve general acceptance. We provide empirical estimations for the marginal effects of the two impacts considered: farms' average income and income distribution. Our estimates consider crop production response to both biophysical and socioeconomic aspects to analyse long-term implications on competitiveness and disparities. As for the results, we find disparities in the adaptation priorities depending on the crop and the region analysed.

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“…The Gini coefficient is probably the most common inequality measure, because its simplicity and its desirable properties. This concentration ratio is widely used in many fields of economics as well as in ecology and agronomics, but there are fewer applications in agricultural and environmental economics together ( [39][40][41]). In a general context, it ranges from zero (equal distribution) to one (perfect inequality), and fulfills the properties of mean independence, population size independence, symmetry, and Pigou Dalton transfer sensitivity ( [42]).…”

Section: Distributional Efficiency Using the Decomposition Of The Ginmentioning

confidence: 99%

Do Water Rights Affect Technical Efficiency and Social Disparities of Crop Production in the Mediterranean? The Spanish Ebro Basin Evidence

Quiroga

Fernández-Haddad²,

Suárez

2014

Water

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Abstract:The coming agenda for the European Common Agricultural Policy includes more incentives for the environmental compliance of farmer's activities. This will be particularly important in the case of water risk management in Mediterranean countries. Among the new challenges is the need to evaluate some of the instruments necessary to comply with the Water Framework Directive requirements that emphasize the management of water demand to achieve the environmental targets. Here we analyze the implications of changing water rights as a policy response to these challenges. We analyze two important aspects of the decision: (i) the effects on the crop productivity and efficiency and (ii) the effects on the rural income distribution. We provide the empirical estimations for the marginal effects on the two considered aspects. First, we calculate a stochastic frontier production function for five representative crops using historical data to estimate technical efficiency. Second, we use a decomposition of the Gini coefficient to estimate the impact of irrigation rights changes on yield disparity. In our estimates, we consider both bio-physical and socio-economic aspects to conclude that there are long term implications on both efficiency and social disparities. We find disparities in the adaptation strategies depending on the crop and the region analyzed.

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Use of Lorenz curves and Gini coefficients to assess yield inequality within paddocks

Cited by 86 publications

References 21 publications

Ecological analysis of antigen-specific CTL repertoires defines the relationship between naïve and immune T-cell populations

Ecological analysis of antigen-specific CTL repertoires defines the relationship between naïve and immune T-cell populations

Climate change and drought effects on rural income distribution in the Mediterranean: a case study for Spain

Do Water Rights Affect Technical Efficiency and Social Disparities of Crop Production in the Mediterranean? The Spanish Ebro Basin Evidence

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