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A kukorica és a vágósertés felvásárlási árának és mennyiségének ciklikussága AgEcon
Hegedusne Baranyai, Nora.
A vizsgálatok a rendszerváltozást követő időszakra vonatkozó piaci folyamatok – árak, felvásárolt mennyiségek – havi változásainak elemzésére irányultak. Célként fogalmazódott meg annak a hipotézisnek az igazolása, miszerint piacgazdasági körülmények között nem elhanyagolható rövid távú ciklikus ingadozásokkal szükséges számolni. A kukorica felvásárlási áránál öt teljes ciklus figyelhető meg az ár alakulásában 1992 januárja és 2011 januárja között. A ciklikus periódusok hossza 3-4 évre tehető. A vágósertésnél szintén öt ciklus rajzolódott ki a vizsgált időszakban. A hullámok hossza változó volt. A sertésáraknál a leghosszabbnak az utolsó előtti tekinthető, a maga három és fél évével. Vizsgálat tárgyát képezte a vonatkozó tényezők sztochasztikus...
Tipo: Article Palavras-chave: Felvásárlási ár és mennyiség; Kukorica; Vágósertés; Ciklikusság; Regresszió; Korreláció; Purchase price and quantity; Corn; Swine; Cyclic changes; Correlation; Regression analysis; Agricultural and Food Policy; Agricultural Finance.
Ano: 2011 URL: http://purl.umn.edu/119940
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Ability of non-linear mixed models to predict growth in laying hens R. Bras. Zootec.
Galeano-Vasco,Luis Fernando; Cerón-Muñoz,Mario Fernando; Narváez-Solarte,William.
In this study, the Von Bertalanffy, Richards, Gompertz, Brody, and Logistics non-linear mixed regression models were compared for their ability to estimate the growth curve in commercial laying hens. Data were obtained from 100 Lohmann LSL layers. The animals were identified and then weighed weekly from day 20 after hatch until they were 553 days of age. All the nonlinear models used were transformed into mixed models by the inclusion of random parameters. Accuracy of the models was determined by the Akaike and Bayesian information criteria (AIC and BIC, respectively), and the correlation values. According to AIC, BIC, and correlation values, the best fit for modeling the growth curve of the birds was obtained with Gompertz, followed by Richards, and then...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Chickens; Mathematical models; Poultry; Regression analysis; Weight gain.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982014001100573
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Adjusting prices for volume: a test of the Hotelling valuation principle AgEcon
Berck, Peter.
This paper tests the hypothesis that the net of extraction cost price of a natural resource does not change with volume. The hypothesis is shown to he a consequence of Hotelling’s theory. The tests are performed on equations estimated by a nonparametric regression (ACE), and we show that the usual least squares estimation techniques are not general enough to successfully perform the test. The test rejects the pure form of the Hotelling theory and shows that it is necessary to adjust sale prices for volume sold.
Tipo: Working or Discussion Paper Palavras-chave: Natural resources; Prices; Regression analysis.
Ano: 1988 URL: http://purl.umn.edu/43665
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Analysis of factors affecting production costs and profitability of milk and dairy products in Turkey Ciênc. Tecnol. Aliment.
AKIN,Ahmet Cumhur; CEVGER,Yavuz.
Abstract White cheese, kashar cheese, yogurt, and ayran are among the most common products produced by the dairy industry in Turkey. The present study determined the production cost of 1 kg of these packaged products as well as the financial implications on their distribution and the total cost. The study also estimated the cost factors affecting the profitability of the products by identifying the cost differences between production regions and scales, using a mean regression model for each product. The study used the data collected through a survey involving 15 dairy plants of three different sizes located in five different regions and involved in raw milk production. The study found a 2-year average capacity utilization rate of the businesses to be...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Dairy industry; Economic; Cost; Husbandry; Regression analysis.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612019000300781
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Analysis of Factors Influencing Development of Resource-saving and Environment-friendly Agriculture in China AgEcon
Gao, Wen; Luo, Min.
By selecting the data from 1989 to 2009 in China, we conduct regression analysis on the total out value of agriculture, the usage amount of chemical fertilizer, total power of agricultural machinery, effective irrigation area, and the damage area. The results show that the usage amount of chemical fertilizer and the damage area, the great obstacle to the construction of resource-saving and environment-friendly agriculture, have significant impact on the output value of agriculture; total power of agricultural machinery and effective irrigation area have insignificant impact on the output value of agriculture. Based on these, the suggestions for promoting the development of resource-saving and environment-friendly agriculture are put forward as follows:...
Tipo: Article Palavras-chave: Resource-saving and environment-friendly agriculture; Influencing factors; Regression analysis; China; Agribusiness.
Ano: 2011 URL: http://purl.umn.edu/119687
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Assessing the significance of covariates in output oriented data envelopment analysis with two stage regression models. Repositório Alice
SOUZA, G. da S. e; GOMES, E. G..
We propose alternative regression models to assess the effects of covariates in output oriented DEA scores. We use probability choice models combined with specifications related to the gamma and to the truncated normal families of distributions. These specifications imply different two stage regression models and alternative quasi maximum likelihood estimators. We apply these methods to assess the significance of technical effects ? type of unit, processes improvement and technology impact ? affecting DEA efficiency scores computed to agricultural research production in Brazil, measured through Embrapa. We favor models taking into account the whole sample of efficiency scores and not only the inefficient units. In our application we conclude that type of...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Melhoria de processo; Modelo de regressão; Fatoriais fracionários; Método estatístico; Pesquisa agrícola; Data analysis; Regression analysis; Agricultural research.
Ano: 2014 URL: http://www.alice.cnptia.embrapa.br/handle/doc/993719
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Assessment of participatory management of irrigation schemes in Sri Lanka: Partial reforms, partial benefits AgEcon
Samad, Madar; Vermillion, Douglas Lynn.
Describes the application of a standard methodology developed by IWMI to assess the impact of irrigation management transfer on the performance of irrigation schemes. Includes detailed analysis of the effects of participatory management on the performance of irrigation schemes in Sri Lanka.
Tipo: Report Palavras-chave: Privatization; Policy; Performance evaluation; Indicators; Operating costs; Irrigation management; Economic aspects; Returns; Participatory management; Farmer participation; Government managed irrigation systems; Small scale systems; Large-scale systems; Regression analysis; Models; Agribusiness; Agricultural Finance; Community/Rural/Urban Development; Farm Management; Research and Development/Tech Change/Emerging Technologies.
Ano: 1999 URL: http://purl.umn.edu/44577
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Assessment of performance and impact of irrigation and water resources systems in Taiwan and Sri Lanka: Final report AgEcon
Sakthivadivel, Ramasamy; Aloysius, Noel; Matsuno, Yutaka.
Tipo: Working or Discussion Paper Palavras-chave: Irrigation systems; Water scarcity; Water allocation; Water supply; Water quality; Water distribution; Decision making; Water management; Regression analysis; Performance evaluation; Sustainability; Irrigated farming; Agricultural development; Farm size; Irrigation management; Farmers' associations; Rain; Paddy cultivation; Crop yield; Costs; Productivity; Crop Production/Industries; Farm Management; Productivity Analysis; Resource /Energy Economics and Policy.
Ano: 2001 URL: http://purl.umn.edu/92774
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Avaliação da influência do ENOS sobre início da estação chuvosa via modelos semiparamétricos de sobrevivência. Repositório Alice
MAIA, A. de H. N.; PAZIANOTTO, R. A. A.; COELHO, C. A. dos S..
Características da estação chuvosa tais como tempo até o início (T) e sua duração são importantes para o planejamento agrícola, especialmente em regiões com alta variabilidade interanual da estação chuvosa. A variável T é influenciada pelo fenômeno El Niño/Oscilação Sul (ENSO) cuja intensidade pode ser mensurada por anomalias da temperatura da superfície do mar (ATSM). Neste trabalho, quantificamos a influência de ATSM sobre T em Guaramiranga e Juazeiro do Norte (Ceará), utilizando uma abordagem inovadora, a análise de sobrevivência semiparamétrica (ASSP). Para definição do início da estação em cada ano, foi utilizado um critério baseado no total de chuva acumulada em dois dias (20 mm) consecutivos e ausência de veranicos superiores a 10 dias nos trinta...
Tipo: Artigo em anais de congresso (ALICE) Palavras-chave: Modelo de regressão de Cox; Previsão climática sazonal; Avaliação quantitativa de risco.; Pluviometria; Análise estatística; Método estatístico; Rain; Regression analysis.
Ano: 2011 URL: http://www.alice.cnptia.embrapa.br/handle/doc/915343
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Chestnut high forest stands: biometrical study in the north of Portugal IPB - Escola Superior Agrária
Nunes, Luís; Monteiro, Maria do Loreto; Patrício, Maria do Sameiro; Alpuim, Teresa; Martins, Lucílio.
Growing sweet chestnut (Castanea sativa) in high forest stands is a lucrative investment. Wood with medium and large dimensions can attain interesting profitability levels. Furthermore, forest producers are interested of new on this species and decision criteria for the best management are needed for landowners. So, accuracy is very important when evaluating volume in standing trees. Based on regression theory, it is developed predicting equations of wood volume as a function of tree variables easily measured (fast and cheap), such as diameter at breast height (DBH) and tree total height (h). Variable selection in volume equations was based on a stepwise modified procedure (linear models) and using generalized-F tests (nonlinear models). The resulting...
Tipo: Article Palavras-chave: Castanea sativa Mill; High forest; Regression analysis; Volume equations.
Ano: 2005 URL: http://hdl.handle.net/10198/2845
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Comparação de métodos de regressão para avaliar a estabilidade fenotípica em cana-de-açucar. Repositório Alice
ROSSE, L.N.; VENCOVSKY, R.; FERREIRA, D.F..
O objetivo deste trabalho foi comparar dois métodos de regressão empregados para avaliar a estabilidade fenotípica em plantas de cana-de-açúcar, o linear, de Cruz et al., e o não-linear, de Toler & Burrows. Utilizaram-se as informações do ensaio de caracterização de 1994 do programa de melhoramento genético da Copersucar, compreendendo 13 locais e 20 genótipos de cana-de-açúcar no Estado de São Paulo. Os resultados permitiram concluir que ambos os modelos se ajustaram satisfatoriamente aos dados. As estimativas da qualidade ambiental pelos dois modelos mostraram diferenças entre seus valores, porém foram concordantes para inferir sobre os melhores e piores ambientes. Ao classificar os genótipos com base na produtividade e no padrão de resposta, no...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Saccharum; Interação genótipo-ambiente; Modelos; Análise de regressão; Genotype environment interaction; Models; Regression analysis.
Ano: 2002 URL: http://www.alice.cnptia.embrapa.br/handle/doc/106109
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Comparação de modelos lidar para a estimativa de biomassa seca acima do solo de florestas com diferentes históricos de perturbação natural ou antrópica no Estado do Acre. Repositório Alice
OLIVEIRA, M. V. N. d'; OLIVEIRA, L. C. de.
Lidar data has been largely used to produce estimative on biomass and timber stocks in tropical forests. A major problem is the lidar flights costs, and the exhaustive and expensive ground plot data acquisition necessary to calibrate lidar data metrics. The use of ground information from previously established plots and the generalization of existent models to structurally similar forests should be a way to minimize these costs. In this work we study six forest in Acre state with similar structure and different disturbance history covered by lidar flights and forest inventories. We investigate whether the use of plots with different sizes violate the null hypothesis of the variance equality of the lidar metrics and tested the use of a lidar general model...
Tipo: Artigo em anais de congresso (ALICE) Palavras-chave: Geotécnica; Terra Indígena Kaxinawá de Nova Olinda (AC); Feijó (AC); Floresta Estadual do Antimary (AC); Bujari (AC); Sena Madureira (AC); Projeto de Assentamento Dirigido Humaita (AC); Porto Acre (AC); Fazenda Bonal; Senador Guiomard (AC); Embrapa Acre; Rio Branco (AC); Acre; Amazônia Ocidental; Western Amazon; Amazonia Occidental; Biomassa; Parte aérea; Estimativa; Sensoriamento remoto; Raio laser; Análise estatística; Regressão linear; Aboveground biomass; Remote sensing; Lidar; Lasers; Statistical analysis; Regression analysis; Biomasa aérea; Teledetección; Lásers; Análisis estadístico; Análisis de regresión.
Ano: 2017 URL: http://www.alice.cnptia.embrapa.br/handle/doc/1072023
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Computational resources for analysis of demographic parameters of arthropod populations. Repositório Alice
MAIA, A. de H. N.; PAZIANOTTO, R. A. A.; LUIZ, A. J. B.; PERVEZ, A..
2014
Tipo: Resumo em anais de congresso (ALICE) Palavras-chave: Fertility life table; SAS codes; R codes; Jackknife; Arthropod populations; Estatística; Regression analysis; Arthropods.
Ano: 2014 URL: http://www.alice.cnptia.embrapa.br/handle/doc/1004803
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Cranial Capacity in an Adult Sri Lankan Population: Sexual Dimorphism and Ethnic Diversity International Journal of Morphology
Ilayperuma,I.
Cranial capacity exerts a close correlation with the volume of the brain. A large body of evidence shows a clear racial variation in cranial dimensions. Therefore detailed knowledge of the population specific data on biometric features of the cranial cavity is important in the study and comparison of the crania of populations from different racial backgrounds, assessing growth and development of an individual and in the diagnosis of any abnormalities of cranial size and shape. Despite its significance, little is known concerning the cranial capacity in Sri Lankans. Hence, the present study was undertaken to establish the cranial capacity in an adult Sri Lankan population. A total of 210 subjects with an age span of 20-23 years were included in the study....
Tipo: Journal article Palavras-chave: Cranial capacity; Linear dimensions; Regression analysis; Sri Lanka.
Ano: 2011 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-95022011000200029
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Determinants of Trust between Buyers and Suppliers in Agribusiness: Empirical Evidence from the German Pork Sector AgEcon
Schulze, Birgit; Spiller, Achim.
There are several hints that there is lack of trust in the relationships between farmers and processors in the meat industry. To generate instruments of trust management, a survey is conducted in the German pork chain measuring the level of trust perceived by farmers as well as the antecedents of trust. Overall satisfaction, the perceived neutrality of the carcass grading system, fairness and farmer orientation are the most import factors explaining trust.
Tipo: Conference Paper or Presentation Palavras-chave: Satisfaction; Reliability; Regression analysis; Pork chain; Agribusiness; Livestock Production/Industries.
Ano: 2006 URL: http://purl.umn.edu/7719
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Development of a clinical scoring system for the diagnosis of smear-negative pulmonary tuberculosis BJID
Soto,Alonso; Solari,Lely; Agapito,Juan; Acuna-Villaorduna,Carlos; Lambert,Marie-Laurence; Gotuzzo,Eduardo; Stuyft,Patrick Van der.
This study developed a clinical score based on clinical and radiographic data for the diagnosis of smear-negative pulmonary tuberculosis (SNPT). SNPT was defined as a positive culture in Ogawa in a patient with two negative sputum smears. Data from patients admitted to the emergency ward with respiratory symptoms and negative acid-fast bacilli (AFB) smears was analyzed by means of logistic regression to develop the predictive score.Two hundred and sixty two patients were included. Twenty patients had SNPT. The variables included in the final model were hemoptysis, weight loss, age > 45 years old, productive cough, upper-lobe infiltrate, and miliary infiltrate. With those, a score was constructed. The score values ranged from -2 to 6. The area under the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Tuberculosis; Pulmonary; Regression analysis; Scoring methods.
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-86702008000200006
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Digestible tryptophan requirements for broilers from 22 to 42 days old R. Bras. Zootec.
Duarte,Karina Ferreira; Junqueira,Otto Mack; Filardi,Rosemeire da Silva; Siqueira,Jefferson Costa de; Puzotti,Maíra Mangili; Garcia,Edivaldo Antônio; Molino,Andrea de Britto; Laurentiz,Antonio Carlos de.
The objective of this experiment was to establish different criteria to evaluate the requirements of digestible tryptophan for broilers from 22 to 42 d of age, using different regression models (quadratic, exponential and Linear Response Plateau) and in case of statistical significance the comparison of means by Duncan test at 5% probability was also adopted. A total of 1,920 Cobb 500 male broilers were distributed in a completely randomized experimental design, with 6 treatments (6 digestible tryptophan levels: 0.1395, 0.1610, 0.1825, 0.2040, 0.2255 and 0.2470%) and 8 replications containing 40 broilers each. Performance and carcass characteristics were evaluated. The level of 0.2255% of digestible tryptophan numerically improves feed conversion, and the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Digestible amino acids; Ideal protein; Performance; Regression analysis.
Ano: 2013 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982013001000006
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Distribution of goat breeds in brazil and their relationship with environmental controls. Repositório Alice
McMANUS, C.; HERMUCHE, P.; PAIVA, S. R.; DALTRO, D.; Evelyn München ALFONZO, E. M.; FACO, O..
Abstract: The localization of all flocks of purebred goats in Brazil was spatialized in ARCGIS along with climatic (THI, precipitation, topography, relative humidity) and physical environmental controls (altitude, pasture type). Data were analysed using analysis of variance, logisitic regression and cluster analyses. Distance matrices were constructed using longitude/latitude and those from environmental controls and these were correlated using Mantel test. Midpoint for most breeds was in Bahia State, but in Pernambuco for locally adapted breeds. The Anglonubian was the commercial breed with the northernmost midpoint. Toggenburg, Saanen and Apline breeds had the southernmost midpoint. There was little difference between environmental controls for locally...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Correlação de Mantel; Precipitação; Regressão logistica; Caprino; Raça; Pastagem; Temperatura; Recurso genético; Goats; Pastures; Temperature; Breeds (animals); Animal genetic resources; Regression analysis.
Ano: 2014 URL: http://www.alice.cnptia.embrapa.br/handle/doc/1007019
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Driving Factors and Model of Change in Arable Land Area in China AgEcon
Lei, Zhanbo; Du, Haowen.
We analyze the characteristics of the change in arable land area in China according to the change data of arable land area and other relevant data from the year 1996 to 2006, and adopt Factor Analysis Method and Stepwise Regression Method to carry out quantitative analysis on the driving factors of arable land change of China. We also establish the regression model of driving factors and arable land area. Finally, some corresponding suggestions are put forward.
Tipo: Thesis or Dissertation Palavras-chave: Arable land; Driving factor; Factor analysis; Regression analysis; China; Land Economics/Use; Research Methods/ Statistical Methods.
Ano: 2009 URL: http://purl.umn.edu/53592
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Equations to estimate tree gaps in a precision forest management area the Amazon based on crown morphometry. Repositório Alice
FIGUEIREDO, E. O.; OLIVEIRA, M. V. N. d'; FEARNSIDE, P. M.; BRAZ, E. M.; PAPA, D. de A..
The precision forest management technique still has much to be improved with the incorporation of forest biometric techniques and forest profiling with airborne LIDAR. When planning the cutting of a tree in forest management, the volume to be produced for industry is estimated but not the area impacted by removal of the tree. The objective of the present study was to develop equations for the Amazon rainforest that are able to estimate the impact area of gaps from harvesting individual dominant and co-dominant trees based on the canopy morphology obtained through forest profiling. On two separate occasions profiles were made in an annual forest-production unit in the Antimary State Forest (FEA) in the state of Acre, Brazil. The first was done a few days...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Manejo de precisão; Clareira; Morfometria; Copa; Perfilamento florestal; Floresta Estadual do Antimary (AC); Bujari (AC); Sena Madureira (AC); Acre; Amazônia Ocidental; Western Amazon; Amazonia Occidental; Morfometria; Administração florestal; Floresta tropical; Biometria; Raio laser; Análise estatística; Regressão linear; Morphometry; Forest management; Tropical forests; Biometry; Canopy gaps; Tree crown; Lasers; Lidar; Statistical analysis; Regression analysis; Morfometría; Manejo forestal; Bosques tropicales; Biometría; Espacios vacíos en el dosel; Copa de los árboles; Lásers; Análisis estadístico; Análisis de regresión.
Ano: 2017 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1088681
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