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	Provedor de dados Horticultura Brasileira (1) Autor Araujo,Charles de (1) Coelho,Maurício Bernardes (1) Fontes,Paulo Cezar Rezende (1) Sediyama,Carlos Sigueyuki (1) Palavra-chave Adubação nitrogenada (1) Eficiência de uso do nitrogênio (1) Fertirrigação (1) Lycopersicon esculentum (1) Nitrato no solo (1) Produção esperada de frutos (1) Mais... Tipo do documento Info:eu-repo/semantics/article (1) Ano 2007 (1) País Brazil (1) Idioma Português (1)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 33 Primeira ... 1 2 ... Última Effect of Policy Interventions on Food Security in Tigray, Northern Ethiopia Ecology and Society van der Veen, Anne; Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente; veen@itc.nl; Gebrehiwot, Tagel; PhD Student, University of Twente, Faculty of Geo-Information Science & Earth Observation ; gidey17146@itc.nl. Following the design of a conservation-based agricultural development strategy and food security strategy, the Tigray government has implemented different pro-poor development programs over the past years to address the problems of food security. This study attempts to investigate the effectiveness of government policy interventions at different scales addressed to improve food security. Food security both at the regional and district level was investigated by deriving food balance sheets for the period 2000-2008. An empirical analysis based on a logit model was also employed to analyze household level food security status. The results of the logit model reveal that government policy interventions such as water harvesting schemes, employment generation... Tipo: Peer-Reviewed Reports Palavras-chave: Effectiveness; Food security; Logit; Policy. Ano: 2011 Simplified Marginal Effects in Discrete Choice Models AgEcon Anderson, Soren T.; Newell, Richard G.. We show that after a simple normalization of explanatory variables so that they equal zero at some desired reference point, marginal effects for continuous variables in probit and logit models simplify dramatically, becoming a function of only the estimated constant term. We present similar simplifications for computation of the asymptotic variance of marginal effects, as well as for the effects of dummy variables on predicted probabilities. We provide a simple table, which in combination with raw probit or logit estimates, is all one needs to compute the desired effects. Tipo: Working or Discussion Paper Palavras-chave: Logit; Probit; Discrete choice; Binary choice; Marginal effect; Data normalization; Research Methods/ Statistical Methods; C25; C51; C81. Ano: 2003 URL: http://purl.umn.edu/10631 Boolean logit and probit in Stata AgEcon Braumoeller, Bear F.. This paper introduces new statistical models, Boolean logit and probit, that allow researchers to model binary outcomes as the results of Boolean interactions among independent causal processes. Each process (or “causal path”) is modeled as the unobserved outcome in a standard logit or probit equation, and the dependent variable is modeled as the observed product of their Boolean interaction. Up to five causal paths can be modeled, in any combination—A and B and C produce Y, A and (B or [C and D]) produce Y, etc. Tipo: Journal Article Palavras-chave: Mlboolean; Dichotomous dependent variable; Boolean; Logit; Probit; Multiple causal paths; Complexity; Random utility; Research Methods/ Statistical Methods. Ano: 2004 URL: http://purl.umn.edu/116271 Food Processors’ Use of Contracts to Purchase Agricultural Inputs: Evidence from a Pennsylvania Survey AgEcon Jaenicke, Edward C.; Shields, Martin; Kelsey, Timothy W.. Using data from a survey of Pennsylvania food processors, we investigate what firm-level characteristics make a processor more or less likely to buy agricultural inputs and ingredients though contracts. We find that over 20 percent of Pennsylvania processors use contracts, and over 44 percent of agricultural inputs (based on value) are purchased under contract. We also analyze the two related questions of what firm attributes, attitudes, or other factors make a firm more likely to use contracts at all, and what factors lead a processor who does contract to use them more intensively. Tipo: Journal Article Palavras-chave: Contracting; Food processors; Logit; Sample selection; Agribusiness; Agricultural Finance. Ano: 2007 URL: http://purl.umn.edu/44698 Odds ratios and logistic regression: further examples of their use and interpretation AgEcon Hailpern, Susan M.; Visintainer, Paul F.. Logistic regression is perhaps the most widely used method for adjustment of confounding in epidemiologic studies. Its popularity is understandable. The method can simultaneously adjust for confounders measured on different scales; it provides estimates that are clinically interpretable; and its estimates are valid in a variety of study designs with few underlying assumptions. To those of us in practice settings, several aspects of applying and interpreting the model, however, can be confusing and counterintuitive. We attempt to clarify some of these points through several examples. We apply the method to a study of risk factors associated with periventricular leucomalacia and intraventricular hemorrhage in neonates. We relate the logit model to... Tipo: Journal Article Palavras-chave: Cc; Cci; Cs; Csi; Logistic; Logit; Relative risk; Case–control study; Odds ratio; Cohort study; Research Methods/ Statistical Methods. Ano: 2003 URL: http://purl.umn.edu/116084 Determinants of Decision to Pay a Price Premium for Modified Food by Consumers of the Republic of Korea AgEcon Kaya, Ozgur; Florkowski, Wojciech J.; Suh, Dong-Kyun. The knowledge of the overall willingness-to-pay and the specific price premiums consumers accept when buying foods with less fat, saturated fat, sodium, sugar and more fiber shapes food manufacturer and distributor marketing strategies and supports the development of public health strategies. This study applies survey data collected in Korea to identify consumer profiles associated with the expressed willingness to pay a premium for foods with nutritionally desired attributes and, next, estimates the influence of consumer and household characteristics on the WTP a particular premium level for such foods. Results indicate the importance of socio-economic variables such as location, income and education, variables representing the risk of health problems... Tipo: Conference Paper or Presentation Palavras-chave: Willingness to pay; Price premium; Modified food; Republic of Korea; Survey data; Logit; Generalized ordered logit; Agricultural and Food Policy; Consumer/Household Economics; Food Consumption/Nutrition/Food Safety; Health Economics and Policy; Q1; C3; D1. Ano: 2010 URL: http://purl.umn.edu/61004 Linking Farmers to Markets: The Case of Grain Marketing Information in Western Kenya AgEcon Odendo, Martins; De Groote, Hugo. Market liberalization created a situation where there are no guaranteed grain prices, no central information source and the need for marketing information increased. Unfortunately, most farmers have little or no access to marketing information. This study evaluates farmers’ perceptions of importance of marketing information; identifies farmers’ sources of grain marketing information; determine farmers’ confidence in and use of marketing information; and assesses determinants farmers’ willingness (WTP) to pay for marketing information. Data used in this study were generated using a structured questionnaire in a survey that covered a random sample of 120 households in traditionally grain surplus-and deficit zones of Kenya. The data were analyzed by... Tipo: Conference Paper or Presentation Palavras-chave: Farmer; Grains; Logit; Markets.; Agricultural and Food Policy; Consumer/Household Economics; Demand and Price Analysis; Environmental Economics and Policy; Farm Management; Food Consumption/Nutrition/Food Safety; Food Security and Poverty; International Relations/Trade; Marketing; Productivity Analysis; Research and Development/Tech Change/Emerging Technologies. Ano: 2008 URL: http://purl.umn.edu/52144 Factors Affecting Maize Producers Adoption of Forward Pricing in Price Risk Management: The Case of Vaalharts AgEcon Jordaan, Henry; Grove, Bennie. Logistic regression is employed to analyse the factors which influence the decision of whether or not the respondent used forward pricing methods during the 2004/05 maize production season. Forward pricing methods include cash forward contracting and hedging with futures contracts and/or options, through the South African Futures Exchange (SAFEX). Based on the results, the use of forward pricing is associated with lower levels of risk aversion and higher levels of human capital. Factor analysis is employed to reduce the dimensionality of the personal reasons which help to interpret the underlying, common factor of the personal reasons why farmers are reluctant to use forward pricing methods. Three factors were extracted and were labelled “Lack of... Tipo: Journal Article Palavras-chave: Forward pricing; Logit; Factor analysis; Agricultural Finance; Risk and Uncertainty. Ano: 2007 URL: http://purl.umn.edu/7049 FARM COMPUTER ADOPTION IN THE GREAT PLAINS AgEcon Hoag, Dana L.; Ascough, James C.; Frasier, W. Marshall. Computers change rapidly, yet the last survey on computer use in agriculture was in 1991. We surveyed Great Plains producers in 1995 and used logit analysis to characterize adopters and non-adopters. About 37% of these producers use computers which is consistent with the general population. We confirmed previous surveys emphasizing the importance of education, age/experience, and other farm characteristics on adoption. However, we also found that education and experience may no longer be a significant influence. Future research and education could focus on when and where computers are most needed, and therefore when adoption is most appropriate. Tipo: Journal Article Palavras-chave: Adoption; Agriculture; Computers; Farmers; Great Plains; Logit; Farm Management. Ano: 1999 URL: http://purl.umn.edu/15144 Intra-class correlation in random-effects models for binary data AgEcon Rodriguez, German; Elo, Irma. We review the concept of intra-class correlation in random-effects models for binary outcomes as estimated by Stata’s xtprobit, xtlogit, and xtclog. We consider the usual measures of correlation based on a latent variable formulation of these models and note corrections to the last two procedures. We also discuss alternative measures of association based on manifest variables or actual outcomes and introduce a new command xtrho for computing these measures for all three types of models. Tipo: Journal Article Palavras-chave: Intra-class correlation; Random-effects; Probit; Logit; Complementary log-log; Pearson's r; Yule's Q; Research Methods/ Statistical Methods. Ano: 2002 URL: http://purl.umn.edu/116030 Export Market Linkage via Gentleman's Agreement: Evidence from French Bean Marketing in Kenya AgEcon Kariuki, Isaac Maina; Gideon, Aiko Obare; Loy, Jens-Peter. "Gentleman's agreements" involving handshakes or promissory market access possibilities through brokers and middlemen have enabled most small farmers in Kenya to export an extensive array of fruits and vegetables. However, despite rapid expansion into these forms of market linkages, there has been a dearth of empirical information regarding the factors that such marketers consider when linking small farmers to the market. This paper uses data from a 2001 French bean farmers survey conducted in Mwea Tebere Central Kenya to evaluate household and infrastructural factors determining informal linkages for French bean marketing. Logit estimates show that irrigation equipment is a prerequisite for linkage, farm localities further from central crop collection... Tipo: Conference Paper or Presentation Palavras-chave: Verbal agreement; Logit; French beans exports; Small farmers; Linkage; Brokers and middlemen; International Relations/Trade. Ano: 2006 URL: http://purl.umn.edu/25698 Purchasing Locally Produced Fresh Vegetables: National Franchise vs. Locally Owned and Operated Restaurants AgEcon Rimal, Arbindra; Benjamin, Onyango. The objective of this study is to examine purchasing practices of locally produced fresh vegetables among restaurants and food service institutions. The sample for the study included managers of 75 restaurants and dining centers out of a total of nearly 600 food service outlets in a mid-size metropolitan city in Midwest with a population of about 400,000. The study findings show differential preferences between national/regional chains and the local independently owned restaurants. Although managers across the board expressed willingness to buy local, actual purchasing decisions were largely driven by freshness, quality and availability. Price was not as critical a factor as others including variety and selection. The results suggest that local vegetable... Tipo: Conference Paper or Presentation Palavras-chave: Local food; Restaurant managers; Logit; Agribusiness. Ano: 2011 URL: http://purl.umn.edu/103464 An Extension of the Blinder-Oaxaca Decomposition Technique to Logit and Probit Models AgEcon Fairlie, Robert W.. The Blinder-Oaxaca decomposition technique is widely used to identify and quantify the separate contributions of group differences in measurable characteristics, such as education, experience, marital status, and geographical differences to racial and gender gaps in outcomes. The technique cannot be used directly, however, if the outcome is binary and the coefficients are from a logit or probit model. I describe a relatively simple method of performing a decomposition that uses estimates from a logit or probit model. Expanding on the original application of the technique in Fairlie (1999), I provide a more thorough discussion of how to apply the technique, an analysis of the sensitivity of the decomposition estimates to different parameters, and the... Tipo: Working or Discussion Paper Palavras-chave: Logit; Probit; Decomposition; Race; Gender; Discrimination; Research Methods/ Statistical Methods; C8; J7. Ano: 2003 URL: http://purl.umn.edu/28425 Iowa Cooperative Fertilizer Retail Outlets: Farmers' Attitudes and Perceptions AgEcon Gensch, Dennis H.. Based on a sample of Iowa farmers, attributes of fertilizer retail dealers are evaluated. Honest management, making deliveries on time, relative size, willingness to negotiate price, and marketing grain are the most important attributes affecting a farmer's decision to patronize an independent or cooperative dealer. Cooperative outlets are generally in a strong competitive position. The study also shows much salient information can be generated by using such statistical methods as segmentation analysis, factor analysis, and the choice model approach. Tipo: Report Palavras-chave: Fertilizer; Supply cooperative; Farmers' perception; Dealer attributes; Segmentation analysis; Factor analysis; Choice model; Logit; Agribusiness. Ano: 1983 URL: http://purl.umn.edu/52018 Determinants of Rural-Urban Migration in Konkan Region of Maharashtra AgEcon Thorat, V.A.; Dhekale, J.S.; Patil, H.K.; Tilekar, S.N.. The study has identified the factors responsible for rural-urban migration based on 120 sample respondents each of migrants and non-migrants spread over two districts, viz. Ratnagiri and Sindhudurg of Konkan region of Maharashtra by employing the logit model. The study has highlighted the importance of rural development programs like MGNREGA that are being implemented by the government with a view to provide employment and income to the rural population in the country. It has also shown that for both migrant and non-migrant households,, agriculture was the major source of income, and their consumption expenditure was more than the production expenditure. It has also been observed that migration has a positive impact on income, expenditure and net savings... Tipo: Article Palavras-chave: Migration; Logit; Variable inflation factor; Odds ratio; Agricultural and Food Policy; J11; J61; C13; R23. Ano: 2011 URL: http://purl.umn.edu/119399 A LOGIT ANALYSIS OF PARTICIPATION IN TENNESSEE'S FOREST STEWARDSHIP PROGRAM AgEcon Bell, Caroline D.; Roberts, Roland K.; English, Burton C.; Park, William M.. This study determines the likely effect of cost-share incentives on participation in the Tennessee Forest Stewardship Program and identifies other factors that may contribute to participation. A random utility model is used to determine the probability that a landowner will choose to participate in the program. A binary choice model is specified to represent the dichotomous decision and a logit procedure is used to fit the model. Data are obtained from mail surveys of 4,000 randomly selected landowners. Results indicate that attitudes and knowledge of forestry programs may be more influential in a landowner's decision to participate than monetary incentives. Tipo: Journal Article Palavras-chave: Cost-share incentive; Stewardship Incentive Program; Logit; Nonindustrial private forest; NIPF; Participation; Forestry; Trees; Resource /Energy Economics and Policy. Ano: 1994 URL: http://purl.umn.edu/15185 Emerging Markets for GM Foods: A Study of Consumer's Willingness to Pay in India AgEcon Deodhar, Satish Y.; Ganesh, Sankar; Chern, Wen S.. A random utility approach is used to estimate logit equations which indicate what factors affect the likelihood of consumption of non-GM and GM foods, and, whether or not consumers are willing to pay a premium for non-GM/GM foods. Ceteris paribus as the price difference between non-GM and GM food rose, people were more likely to consume GM foods. Likelihood of GM food consumption was higher in the middle income brackets. Consumers were willing to pay an expected premium of 19.5% and 16.12% for golden rice and GM edible oil respectively. In case of chicken, consumers seemed to pay a very negligible premium for non-GM fed chicken. Overall, it appears that GM foods may be acceptable in the Indian market. However, basic awareness about the GM foods may... Tipo: Conference Paper or Presentation Palavras-chave: GM Foods; Golden Rice; Bt cottonseed oil; GM fed chicken; Willingness to Pay; Random utility approach; Logit; India.; Demand and Price Analysis; Food Consumption/Nutrition/Food Safety; Q13; D12. Ano: 2008 URL: http://purl.umn.edu/6348 Consumer preferences and labelling: an empirical analysis of the beef sector in Italy AgEcon Banterle, Alessandro; Stanieri, S.. Within the framework of European food safety measures, Reg. 1760/2000 and 1825/2000 have introduced mandatory traceability and relevant labeling into the beef sector. The paper analyses whether information on meat labels can be considered a useful instrument for consumers, facilitating the verification of quality. The purpose of the paper is, first, to evaluate if meat information is used during food purchase. Second, focusing on specific meat information, we assess the interest of consumer for some mandatory and voluntary information cues and identify the determinants affecting the use of them. Data were collected by a survey conducted in the Lombardy, region of the northern Italy, and employed a telephone questionnaire. The sample is composed by 1,025... Tipo: Conference Paper or Presentation Palavras-chave: Traceability; Meat; Consumer preferences; Logit; Demand and Price Analysis. Ano: 2008 URL: http://purl.umn.edu/43547 Media Impact of Nutrition Information on Food Choice AgEcon Shiratori, Sakiko; Kinsey, Jean D.. This study estimated the impact of nutrition information provided by popular media on consumers’ purchases in U.S. grocery stores, taking omega-3 fortified eggs as an example. The media index was constructed from multiple information sources by utilizing computer-coded content analysis. Their probability of purchasing omega-3 eggs between 1998 and 2007 based on household-level scanner data was analyzed by logistic regression models to incorporate elements of information effects. The results showed the significant positive impact of nutritional information from the popular media on consumers’ food choices, thus publishing in popular media can be an effective communication approach to promote consumers’ health. Tipo: Conference Paper or Presentation Palavras-chave: Consumer Economics; Content Analysis; Functional Food; Information economics; Logit; Omega-3 Fatty Acids; Consumer/Household Economics; Food Consumption/Nutrition/Food Safety; D12; D83. Ano: 2011 URL: http://purl.umn.edu/103850 Live Animal Ultrasound Information as a Decision Tool in Replacement Beef Heifer Programs AgEcon Dos Santos, Alecsandro; Anderson, John D.; Vann, Rhonda C.; Willard, Scott T.. Real-time ultrasound information taken on beef heifers prior to backgrounding is used to develop a logit model to aid heifer retention decisions. The value of ultrasound data is calculated as the difference in certainty equivalents between a decision rule incorporating ultrasound information and one using only visual cues. The value of ultrasound data is found to be around $10 per head but is influenced by heifer value and backgrounding costs. Tipo: Journal Article Palavras-chave: Expected utility; Heifer development; Logit; Real-time ultrasound; Agribusiness; Agricultural and Food Policy; Livestock Production/Industries; Q11; Q12; Q13. Ano: 2008 URL: http://purl.umn.edu/45529 Registros recuperados: 33 Primeira ... 1 2 ... Última

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