Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

Records 1 - 20 / 49

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: q=Trujillo
Check title to add to marked list
Concentration and liquidity costs in emerging commodity exchanges
Costa, Geraldo ; Trujillo-Barrera, Andres ; Pennings, Joost M.E. - \ 2018
Journal of Agricultural and Resource Economics 43 (2018)3. - ISSN 1068-5502 - p. 441 - 456.
Bid-ask spread - Volatility - Volume

We analyze the relationships among liquidity costs, volume, and volatility in the Brazilian agricultural futures market, along with the role of market concentration. We estimate a structural three-equation IV-GMM model using data from Bolsa, Brasil, Balcão corn and live cattle contracts from March 2014 to February 2016. Results show a negative association between liquidity costs and volume and a positive association between liquidity costs and volatility. Market concentration impacts corn and live cattle differently. Concentration contributes to volume reduction for live cattle and to liquidity costs reduction for corn. Our findings shed light on the microstructure of emerging markets.

Functional genetics and genomics of the banana black Sigatoka pathogen Pseudocercospora fijiensis
Díaz Trujillo, Caucasella - \ 2018
University. Promotor(en): Gert Kema; Pierre de Wit, co-promotor(en): R.E. Arango. - Wageningen : Wageningen University - ISBN 9789463323642 - 247
Short-term price density forecasts in the lean HOG futures market
Trujillo-Barrera, Andres ; Garcia, Philip ; Mallory, Mindy L. - \ 2018
European Review of Agricultural Economics 45 (2018)1. - ISSN 0165-1587 - p. 121 - 142.
Commodities - Density forecast - Price analysis
We estimate and evaluate ex-ante density forecasts of lean hog futures prices using two approaches: forward-looking techniques using options market data and time series models. Our findings indicate that risk-neutral and risk-adjusted forward-looking market techniques are better calibrated and have superior predictive accuracy than time series GARCH models based on historical data. Improvements to goodness of fit and accuracy of the forecasts obtained by the calibration from risk-neutral to real-world densities imply that short-term risk premiums may be present in the lean hog futures markets, and they most likely appear in periods of market turmoil.
Targeted and random genetic modification of the black Sigatoka pathogen Pseudocercospora fijiensis by Agrobacterium tumefaciens-mediated transformation
Díaz-Trujillo, Caucasella ; Kobayashi, Adilson K. ; Souza, Manoel ; Chong, Pablo ; Meijer, Harold J.G. ; Arango Isaza, Rafael E. ; Kema, Gert H.J. - \ 2018
Journal of Microbiological Methods 148 (2018). - ISSN 0167-7012 - p. 127 - 137.
Stress and sexual reproduction affect the dynamics of the wheat pathogen effector AvrStb6 and strobilurin resistance
Kema, Gerrit H.J. ; Mirzadi Gohari, Amir ; Aouini, Lamia ; Gibriel, Hesham A.Y. ; Ware, Sarah B. ; Den Bosch, Frank van; Manning-Smith, Robbie ; Alonso-Chavez, Vasthi ; Helps, Joe ; M’Barek, Sarrah Ben; Mehrabi, Rahim ; Diaz-Trujillo, Caucasella ; Zamani, Elham ; Schouten, Henk J. ; Lee, Theo A.J. van der; Waalwijk, Cees ; Waard, Maarten A. de; Wit, Pierre J.G.M. de; Verstappen, Els C.P. ; Thomma, Bart P.H.J. ; Meijer, Harold J.G. ; Seidl, Michael F. - \ 2018
Nature Genetics 50 (2018). - ISSN 1061-4036 - p. 375 - 380.
Host resistance and fungicide treatments are cornerstones of plant-disease control. Here, we show that these treatments allow sex and modulate parenthood in the fungal wheat pathogen Zymoseptoria tritici. We demonstrate that the Z. tritici–wheat interaction complies with the gene-for-gene model by identifying the effector AvrStb6, which is recognized by the wheat resistance protein Stb6. Recognition triggers host resistance, thus implying removal of avirulent strains from pathogen populations. However, Z. tritici crosses on wheat show that sex occurs even with an avirulent parent, and avirulence alleles are thereby retained in subsequent populations. Crossing fungicide-sensitive and fungicide-resistant isolates under fungicide pressure results in a rapid increase in resistance-allele frequency. Isolates under selection always act as male donors, and thus disease control modulates parenthood. Modeling these observations for agricultural and natural environments reveals extended durability of host resistance and rapid emergence of fungicide resistance. Therefore, fungal sex has major implications for disease control.
A new mechanism for reduced sensitivity to demethylation-inhibitor fungicides in the fungal banana black Sigatoka pathogen Pseudocercospora fijiensis
Díaz-Trujillo, C. ; Chong, P. ; Stergiopoulos, I. ; Meijer, H.J.G. ; Wit, P.J.G.M. de; Kema, G.H.J. - \ 2018
Molecular Plant Pathology 19 (2018)6. - ISSN 1464-6722 - p. 1491 - 1503.
The Dothideomycete Pseudocercospora fijiensis, previously Mycosphaerella fijiensis, is the causal agent of black Sigatoka, one of the most destructive diseases of bananas and plantains. Disease management depends on fungicide applications with a major share for sterol demethylation-inhibitors (DMIs). The continued use of DMIs puts a considerable selection pressure on natural P. fijiensis populations enabling the selection of novel genotypes with reduced sensitivity. The hitherto explanatory mechanism for this reduced sensitivity was the presence of non-synonymous point mutations in the target gene Pfcyp51, encoding the sterol 14α-demethylase enzyme. Here, we demonstrate a second mechanism involved in DMI sensitivity of P. fijiensis. We identified a 19bp element in the wild type (wt) Pfcyp51 promoter that concatenates in strains with reduced DMI sensitivity. A PCR assay identified up to six Pfcyp51 promoter repeats in four field populations of P. fijiensis in Costa Rica. We used transformation experiments to swap the wild type promoter of a sensitive field isolate with a promoter from a strain with reduced DMI sensitivity that comprised multiple insertions. Comparative in vivo phenotyping showed a functional and proportional upregulation of Pfcyp51, which consequently decreased DMI sensitivity. Our data demonstrate that point mutations in the Pfcyp51 coding domain as well as promoter inserts contribute to reduced DMI sensitivity of P. fijiensis. These results bring new insights into the importance of the appropriate use of DMIs and the need for the discovery of new molecules for black Sigatoka management.
Volatility spillover and time-varying conditional correlation between DDGS, corn, and soybean meal markets
Etienne, Xiaoli L. ; Trujillo-Barrera, Andrés ; Hoffman, Linwood A. - \ 2017
Agricultural and Resource Economics Review 46 (2017)3. - ISSN 1068-2805 - p. 529 - 554.
Corn - Distiller's dried grains with solubles (DDGS) - Dynamic correlations - Price - Soybean meal - Spillover - Volatility

We find distiller's dried grains with solubles (DDGS) prices to be positively correlated with both corn and soybean meal prices in the long run. However, neither corn nor soybean meal prices respond to deviations from this long-run relationship. We also identify strong time-varying dynamic conditional correlations between the markets, with the correlation between DDGS and corn strengthened after the expansion of ethanol production. There also appear to exist significant volatility spillovers from both the corn and soybean meal markets to the DDGS market, with the impact from corn shocks much larger compared to soybean meal shocks.

Organizers special session “Measurements and Diagnostics of Resilience in the Agri-Food Sector Against Market Risk”
Trujillo Barrera, Andres - \ 2017
Similia Similibus Curantur: Farm Level Risk Balancing Behavior
Tamirat, A. ; Trujillo Barrera, A.A. ; Pennings, J.M.E. - \ 2017
The Role of Income Growth in Emerging Economies on Grain Prices: A Mixed-Frequency Approach
Trujillo Barrera, A.A. ; Pennings, J.M.E. ; Garcia, Philip - \ 2017
Farm Target Capital Structure: Dynamics, Determinants and Speed of Adjustment
Tamirat, A.S. ; Trujillo Barrera, A.A. ; Pennings, J.M.E. - \ 2017
- 37 p.
Farm business - Dynamic partial adjustment model - Target capital structure - Adjustment speed
The corporate finance literature has focused on explaining the determinants of firms target capital structure and speed of adjustment using the well-established theories such as pecking order, signaling and trade-off theories. However, less attention has been paid to understanding the financing behavior of farm businesses using these theories. Unlike corporate firms with professional management, farm businesses are different in a way that family members participate in management, the owner is often the manager, the decision-making unit is small, and farms heavily depend on government subsidies to stabilize income. These distinctive setting in farm business may result in different patterns of capital structure decision-making. Hence, we evaluate the application of corporate finance theories in the context of understanding the relationship between target capital structure and profit in the farm business. We use a dynamic partial adjustment model to examine the determinants of capital structure and speed of adjustment, and detect capital structure theories with which the leverage ratio of farm business would comply. Our sample comprises a panel of 1500 Dutch farms over the years 2001 to 2015. We find strong evidence that farms prefer internal funds to external funds. Profit is negatively related to leverage, supporting the pecking order theory, which has often been rejected for large firms. Consistent with the signaling theory, we find that size is positively related to leverage. Farm asset structure, growth, investment, and earnings volatility significantly determine the target capital structure. An interesting finding is that farm leverage is highly persistent and that lagged leverage is the best predictor of subsequent leverage ratios. Also, farms appear to have target leverage ratio and are reported to adjust their leverage towards the optimal level. The speed of adjustment to the target capital ranges from 8.6% to 63%, and varies by farm size and farm. This evidence further confirms the existence of dynamics in the farm capital structure decision. This article provides insights to understanding the dynamic nature of farm capital structure and the applicability of capital structure theories in the farm business.
Dynamic Capital Structure: Dynamics, Determinants and Speed of Adjustment
Tamirat, A.S. ; Trujillo Barrera, A.A. ; Pennings, J.M.E. - \ 2017
- 36 p.
Farm business, - Dynamic partial adjustment model - Target capital structure - Adjustment speed
The corporate finance literature has focused on explaining the determinants of firms target capital structure and speed of adjustment using the well-established theories such as pecking order, signaling and trade-off theories. However, less attention has been paid to understanding the financing behavior of farm businesses using these theories. Unlike corporate firms with professional management, farm businesses are different in a way that family members participate in management, the owner is often the manager, the decision-making unit is small, and farms heavily depend on government subsidies to stabilize income. These distinctive setting in farm business may result in different patterns of capital structure decision-making. Hence, we evaluate the application of corporate finance theories in the context of understanding the relationship between target capital structure and profit in the farm business.
We use a dynamic partial adjustment model to examine the determinants of capital structure and speed of adjustment, and detect capital structure theories with which the leverage ratio of farm business would comply. Our sample comprises a panel of 1500 Dutch farms over the years 2001 to 2015.
We find strong evidence that farms prefer internal funds to external funds. Profit is negatively related to leverage, supporting the pecking order theory, which has often been rejected for large firms. Consistent with the signaling theory, we find that size is positively related to leverage. Farm asset structure, growth, investment, and earnings volatility significantly determine the target capital structure. An interesting finding is that farm leverage is highly persistent and that lagged leverage is the best predictor of subsequent leverage ratios. Also, farms appear to have target leverage ratio and are reported to adjust their leverage towards the optimal level. The speed of adjustment to the target capital ranges from 8.6% to 63%, and varies by farm size and farm. This evidence further confirms the existence of dynamics in the farm capital structure decision. This article provides insights to understanding the dynamic nature of farm capital structure and the applicability of capital structure theories in the farm business.
Impact of potentially contaminated river water on agricultural irrigated soils in an equatorial climate
Trujillo-González, Juan Manuel ; Mahecha-Pulido, Juan D. ; Torres-Mora, Marco Aurelio ; Brevik, Eric C. ; Keesstra, Saskia D. ; Jiménez-Ballesta, Raimundo - \ 2017
Agriculture 7 (2017)7. - ISSN 2077-0472
Agricultural land use - Equatorial area - Trace elements - Wastewater irrigation

Globally, it is estimated that 20 million hectares of arable land are irrigated with water that contains residual contributions from domestic liquids. This potentially poses risks to public health and ecosystems, especially due to heavy metals, which are considered dangerous because of their potential toxicity and persistence in the environment. The Villavicencio region (Colombia) is an equatorial area where rainfall (near 3000 mm/year) and temperature (average 25.6 °C) are high. Soil processes in tropical conditions are fast and react quickly to changing conditions. Soil properties from agricultural fields irrigated with river water polluted by a variety of sources were analysed and compared to non-irrigated control soils. In this study, no physico-chemical alterations were found that gave evidence of a change due to the constant use of river water that contained wastes. This fact may be associated with the climatic factors (temperature and precipitation), which contribute to fast degradation of organic matter and nutrient and contaminants (such as heavy metals) leaching, or to dilution of wastes by the river.

Business Management Models of Microfinance Institutions (MFIs) in Africa: : A Study into Their Enabling Environments
Pashkova, Nadya ; Trujillo-Barrera, Andres ; Apostolakis, George ; Dijk, Gert Van; Drakos, Periklis D. ; Baourakis, George - \ 2016
International Journal of Food and Beverage Manufacturing and Business Models 1 (2016)2. - ISSN 2379-7509 - p. 63 - 82.
In this study, the authors analyse the socioeconomic, political and geographic conditions that are conducive of cooperative microfinance initiatives in comparison with other organizational forms in Africa. They distinguish three types of institutions (MFIs) and business models: cooperatives/credit unions, non-profit or non-governmental (NGOs and commercial banks). To analyse the enabling environment for the three business models three types of factors are distinguished: macroeconomic policy, institutional, and geographical. Multinomial logistic regression is applied to investigate the impact of these external conditions. The authors use data on 1790 MFIs in selected African countries (MIX Market) and global socioeconomic data of these countries. Their findings reveal that irrespective geographic location, cooperatives feature in countries with civil law systems, low inflation rates and high levels of economic growth. Commercial MFIs (banks) feature particularly in the countries with common law legal systems. NGO type MFIs are associated with high inflation rates and low levels of economic growth.
Price density forecasts in the U.S. HOG Markets : Composite procedures
Trujillo-Barrera, Andres ; Garcia, Philip ; Mallory, Mindy L. - \ 2016
American Journal of Agricultural Economics 98 (2016)5. - ISSN 0002-9092 - p. 1529 - 1544.
Commodity price analysis - density forecast combination

We develop and evaluate quarterly out-of-sample individual and composite density forecasts for U.S. hog prices. Individual density forecasts are generated using time series models and the implied distributions of USDA and Iowa State University outlook forecasts. Composite density forecasts are constructed using linear and logarithmic combinations of the individual forecasts and several weighting schemes. Density forecasts are evaluated on predictive accuracy (sharpness), goodness of fit (calibration), and their economic value in a hedging simulation. Logarithmic combinations using equal and mean square error weights outperform all individual density forecasts and are modestly better than linear composites. Comparison of the outlook forecasts to the best composite demonstrates the usefulness of the composite procedure, and identifies the economic value that more accurate expected price probability distributions can provide to producers.

Does What Go Around Really Come Around? Existence and Determinants of Profit Persistence: Evidence of Dutch Farms
Tamirat, A. ; Trujillo Barrera, A.A. ; Pennings, J.M.E. - \ 2016
Combating a Global Threat to a Clonal Crop : Banana Black Sigatoka Pathogen Pseudocercospora fijiensis (Synonym Mycosphaerella fijiensis) Genomes Reveal Clues for Disease Control
Arango Isaza, Rafael E. ; Diaz-Trujillo, Caucasella ; Dhillon, Braham ; Aerts, Andrea ; Carlier, Jean ; Crane, Charles F. ; V. de Jong, Tristan ; Vries, Ineke de; Dietrich, Robert ; Farmer, Andrew D. ; Fortes Fereira, Claudia ; Garcia, Suzana ; Guzman, Mauricio ; Hamelin, Richard C. ; Lindquist, Erika A. ; Mehrabi, Rahim ; Quiros, Olman ; Schmutz, Jeremy ; Shapiro, Harris ; Reynolds, Elizabeth ; Scalliet, Gabriel ; Souza, Manoel ; Stergiopoulos, Ioannis ; Lee, Theo A.J. van der; Wit, Pierre J.G.M. de; Zapater, Marie Françoise ; Zwiers, Lute Harm ; Grigoriev, Igor V. ; Goodwin, Stephen B. ; Kema, Gert H.J. - \ 2016
Plos Genetics 12 (2016)8. - ISSN 1553-7390

Black Sigatoka or black leaf streak disease, caused by the Dothideomycete fungus Pseudocercospora fijiensis (previously: Mycosphaerella fijiensis), is the most significant foliar disease of banana worldwide. Due to the lack of effective host resistance, management of this disease requires frequent fungicide applications, which greatly increase the economic and environmental costs to produce banana. Weekly applications in most banana plantations lead to rapid evolution of fungicide-resistant strains within populations causing disease-control failures throughout the world. Given its extremely high economic importance, two strains of P. fijiensis were sequenced and assembled with the aid of a new genetic linkage map. The 74-Mb genome of P. fijiensis is massively expanded by LTR retrotransposons, making it the largest genome within the Dothideomycetes. Melting-curve assays suggest that the genomes of two closely related members of the Sigatoka disease complex, P. eumusae and P. musae, also are expanded. Electrophoretic karyotyping and analyses of molecular markers in P. fijiensis field populations showed chromosome-length polymorphisms and high genetic diversity. Genetic differentiation was also detected using neutral markers, suggesting strong selection with limited gene flow at the studied geographic scale. Frequencies of fungicide resistance in fungicide-treated plantations were much higher than those in untreated wild-type P. fijiensis populations. A homologue of the Cladosporium fulvum Avr4 effector, PfAvr4, was identified in the P. fijiensis genome. Infiltration of the purified PfAVR4 protein into leaves of the resistant banana variety Calcutta 4 resulted in a hypersensitive-like response. This result suggests that Calcutta 4 could carry an unknown resistance gene recognizing PfAVR4. Besides adding to our understanding of the overall Dothideomycete genome structures, the P. fijiensis genome will aid in developing fungicide treatment schedules to combat this pathogen and in improving the efficiency of banana breeding programs.

Understanding producers' motives for adopting sustainable practices : The role of expected rewards, risk perception and risk tolerance
Trujillo-Barrera, Andres ; Pennings, Joost M.E. ; Hofenk, Dianne - \ 2016
European Review of Agricultural Economics 43 (2016)3. - ISSN 0165-1587 - p. 359 - 382.
Motivation for adoption of sustainability - Risk perception - Risk tolera

Understanding the motives and risk attitudes of producers to engage in sustainable practices is important for policy-makers who wish to increase the likelihood of adoption and improve the design of incentives. This article examines the underlying motives of producers to adopt sustainable practices. We focus on expected economic, social and personal rewards and analyse the role of producers' financial risk perception and risk tolerance. Results from personal interviews with 164 hog producers show that the adoption of sustainable practices is affected by expected economic rewards but not by social and personal rewards. Further, while perceived risk is a barrier to the adoption of sustainable practices, risk tolerance is a positive moderator of the relationship between economic rewards and adoption. In addition, perceived tax benefits and turnover have a significant positive relationship with adoption, while education and age do not play a role.

Price and volatility transmissions between natural gas, fertilizer, and corn markets
Etienne, Xiaoli Liao ; Trujillo-Barrera, Andrés ; Wiggins, Seth - \ 2016
Agricultural Finance Review 76 (2016)1. - ISSN 0002-1466 - p. 151 - 171.
Conditional volatility - Corn - Fertilizer - Natural gas - Price - Transmission mechanism

Purpose – The purpose of this paper is to investigate the price and volatility transmission between natural gas, fertilizer (ammonia), and corn markets, an issue that has been traditionally ignored in the literature despite its significant importance. Design/methodology/approach – The authors jointly estimate a vector error correction model for the conditional mean equation and a multivariate generalized autoregressive heteroskedasticity model for the conditional volatility equation to investigate the interactions between natural gas, ammonia, and corn prices and their volatility. Findings – The authors find significant interplay between fertilizer and corn markets, while only a mild linkage in prices and volatility exist between those markets and natural gas during the period 1994-2014. There is not only a positive relationship between corn and ammonia prices in the short run, but both prices react to deviations from the long-run parity. Furthermore, the lagged conditional volatility of ammonia prices positively affects conditional volatility in the corn market and vice versa. This result is robust to a specification using crude oil price as an alternative to natural gas price to account for the large transportation cost built into ammonia prices. Results for the period of 2006-2014 indicate virtually no linkage between natural gas prices and those of fertilizer and corn during that period, while linkages in price level and volatility between the latter remain strong. Originality/value – This paper is the first in the literature to comprehensively examine the role of fertilizer on corn prices and volatility, and its relation to natural gas prices.

Heavy metal accumulation related to population density in road dust samples taken from urban sites under different land uses
Trujillo-González, Juan Manuel ; Torres-Mora, Marco Aurelio ; Keesstra, Saskia ; Brevik, Eric C. ; Jiménez-Ballesta, Raimundo - \ 2016
Science of the Total Environment 553 (2016). - ISSN 0048-9697 - p. 636 - 642.
Ecological risk index - Heavy metals - Urban dust - Urban pollution

Soil pollution is a key component of the land degradation process, but little is known about the impact of soil pollution on human health in the urban environment. The heavy metals Pb, Zn, Cu, Cr, Cd and Ni were analyzed by acid digestion (method EPA 3050B) and a total of 15 dust samples were collected from streets of three sectors of the city with different land uses; commercial, residential and a highway. The purpose was to measure the concentrations of heavy metals in road sediment samples taken from urban sites under different land uses, and to assess pollution through pollution indices, namely the ecological risk index and geoaccumulation index. Heavy metals concentrations (mg/kg) followed the following sequences for each sector: commercial sector Pb (1289.4) > Cu (490.2) > Zn (387.6) > Cr (60.2) > Ni (54.3); highway Zn (133.3) > Cu (126.3) > Pb (87.5) > Cr (9.4) > Ni (5.3); residential sector Zn (108.3) > Pb (26.0) > Cu (23.7) > Cr (7.3) > Ni (7.2). The geoaccumulation index indicated that the commercial sector was moderately to strongly polluted while the other sectors fell into the unpolluted category. Similarly, using the ecological risk index the commercial sector fell into the considerable category while the other sectors classified as low risk. Road dust increased along with city growth and its dynamics, additionally, road dust might cause a number of negative environmental impacts, therefore the monitoring this dust is crucial.

Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.