bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of maternal HIV‐1 severity with dental caries: an observational study of uninfected 5‐ to 7‐yr‐old children of HIV‐1‐infected mothers without severe immune suppression
Authors: Birungi Nancy , Fadnes Lars Thore , Engebretsen Ingunn Marie Stadskleiv , Lie Stein Atle , Tumwine James Kashyugyera , Åstrøm Anne Nordrehaug ,   the ANRS 12174 and 12341 study groups
Published: January 2020

Treatment programs to prevent perinatal and postnatal HIV‐1 transmission have become available in sub‐Saharan Africa, leading to an emerging population of HIV‐1 exposed uninfected (HEU) children. Exposure to HIV‐1 in utero and during breastfeeding may increase the risk of morbidity and mortality in HEU children. This study estimated the association of the severity of maternal HIV‐1 infection as assessed by CD4 count and viral load at baseline (7 d postpartum), with  dmft count of their 5‐ to 7‐yr‐old HEU offspring. A follow‐up study was conducted of HIV‐1‐infected mother–HEU children pairs (n = 164) from the Ugandan site of the ANRS 12341‐PROMISE‐ PEP trial (ClinicalTrials.gov, number NCT00640263). HIV‐1‐infected mothers were interviewed and the HEU children were examined for caries using the World Health Organization's survey methods for field conditions and the dmft index. Directed acyclic graphs and negative binomial regression were used for analyses. The prevalence of 1 or more dmft was 48%. Negative binomial regression showed no association between the dmft count and maternal CD4 counts 7 d postpartum but a 10% lower dmft count with longer breastfeeding duration was found. Maternal CD4 count at birth was not associated with the dental caries experience in uninfected children born to women without severe immune suppression, while there appeared to be a protective effect of high viral load and breastfeeding duration.
Associations between the radiographic appearance of vascular channels in proximal sesamoid bones, their microstructural characteristics and past racing performance in Thoroughbreds
Authors: Lloyd Kristen A. , Ayodele Babatunde A. , Hitchens Peta L. , Beck Cathy , Mackie Eleanor J. , Whitton Robert C.
Published: January 2020

Background

Abnormalities in vascular channel appearance within the proximal sesamoid bone (PSB) are the most common findings in Thoroughbred yearling presale radiographs and are often evaluated on radiographs of adult racehorses. Despite this, their pathogenesis and clinical significance are poorly understood, and associations with racing performance are inconsistent.

Objectives

To determine microstructural characteristics of the PSBs associated with the radiographic appearance of vascular channels using microcomputed tomography (µCT) and to determine associations with past racing performance in mature horses.

Study design

Cross‐sectional.

Methods

One pair of PSBs were isolated from a forelimb of 59 Thoroughbred racehorses undergoing post‐mortem examination. Each PSB (n = 118) was radiographed, assigned a vascular channel grade using previously published and novel grading systems, then imaged using µCT. Associations between radiographic, µCT and performance variables were investigated with uni‐ and multivariable generalised linear models.

Results

All PSBs had at least one vascular channel (mean 3.6 ± 0.89) observed on µCT originating from the abaxial border, yet in only 63.6% (75/118) were channels observed radiographically. Proximal sesamoid bones with a higher bone volume fraction (odds ratio [OR] 1.08; 95% confidence interval [CI] 1.01‐1.15;P = .03) and wider channel diameter (mm) on µCT (OR 20.67; 95% CI 3.29‐130.00;P = .001) were more likely to have vascular channels identified on radiographs. Greater radiographic channel number (OR 0.96; 95% CI 0.92‐1.00;P = .04) and channel diameter (mm; OR 0.96; 95% CI 0.92‐1.00;P = .04) were associated with fewer career placings.

Main limitations

Radiographs of isolated bones avoided the normal superimposition of tissue encountered in the live horse.

Conclusions

The ability to identify vascular channels radiographically indicates widening of channels and densification of the PSB. More radiographic channels and greater channel diameter were associated with similar or poorer measures of past performance, suggesting that these changes are not desirable.
Deleterious impact of a generic temozolomide formulation compared with brand‐name product on the kinetic of platelet concentration and survival in newly diagnosed glioblastoma
Authors: Fontanilles Maxime , Fontanilles Adeline , Massy Nathalie , Rouvet Jean , Pereira Tony , Alexandru Cristina , Hanzen Chantal , Basuyau Florence , Langlois Olivier , Clatot Florian , Tennevet Isabelle , Di Fiore Frédéric , Joannidès Robinson , Lamoureux Fabien
Published: January 2020

Chemo‐induced thrombocytopenia is a limiting toxicity among patients receiving temozolomide (TMZ) as first‐line treatment for glioblastoma. We aimed to compare early platelet concentration kinetics, hematological safety profile, and impact on survival following the initiation of either the brand‐name or a generic TMZ formulation. A retrospective trial was conducted in patients suffering from newly diagnosed glioblastoma. Patients were treated with TMZ at 75 mg/m2 per day during six weeks, concomitantly with radiotherapy. Platelet concentration was collected each week. Primary endpoint was to perform a linear mixed‐effect model of platelet concentration kinetic over weeks. A total of 147 patients were included as follows: 96 received the brand‐name TMZ, and 51 received a generic TMZ formulation. Exposition to the generic was a significant variable that negatively influenced the platelet kinetics in the radiotherapy and concomitant TMZ phase, P = 0.02. Grade ≥3 chemo‐induced thrombocytopenia was more frequent in the generic group: 19.6% [95% CI 8.7‐30.5%] vs 3.1% [0‐6.6%], P = 0.001. Exposition to the generic formulation of TMZ led to increase early treatment discontinuation due to TMZ‐induced thrombocytopenia and was a worsening independent prognostic factor on overall survival: adjusted HR 1.83 [1.21‐2.8], P = 0.031. These data suggest that exposition to a generic formulation of TMZ vs the brand‐name product is associated with higher early platelet decrease leading to clinically relevant impacts on treatment schedule in glioblastoma. Further prospective trials are needed to confirm these results.
A socio‐ecological model for predicting impacts of land‐use and climate change on regional plant diversity in the Austrian Alps
Authors: Dullinger Iwona , Gattringer Andreas , Wessely Johannes , Moser Dietmar , Plutzar Christoph , Willner Wolfgang , Egger Claudine , Gaube Veronika , Haberl Helmut , Mayer Andreas , Bohner Andreas , Gilli Christian , Pascher Kathrin , Essl Franz , Dullinger Stefan
Published: January 2020

Climate and land‐use change jointly affect the future of biodiversity. Yet, biodiversity scenarios have so far concentrated on climatic effects because forecasts of land use are rarely available at appropriate spatial and thematic scales. Agent‐based models (ABMs) represent a potentially powerful but little explored tool for establishing thematically and spatially fine‐grained land‐use scenarios. Here, we use an ABM parameterized for 1,329 agents, mostly farmers, in a Central European model region, and simulate the changes to land‐use patterns resulting from their response to three scenarios of changing socio‐economic conditions and three scenarios of climate change until the mid of the century. Subsequently, we use species distribution models to, first, analyse relationships between the realized niches of 832 plant species and climatic gradients or land‐use types, respectively, and, second, to project consequent changes in potential regional ranges of these species as triggered by changes in both the altered land‐use patterns and the changing climate. We find that both drivers determine the realized niches of the studied plants, with land use having a stronger effect than any single climatic variable in the model. Nevertheless, the plants' future distributions appear much more responsive to climate than to land‐use changes because alternative future socio‐economic backgrounds have only modest impact on land‐use decisions in the model region. However, relative effects of climate and land‐use changes on biodiversity may differ drastically in other regions, especially where landscapes are still dominated by natural or semi‐natural habitat. We conclude that agent‐based modelling of land use is able to provide scenarios at scales relevant to individual species distribution and suggest that coupling ABMs with models of species' range change should be intensified to provide more realistic biodiversity forecasts.
Community diversity outweighs effect of warming on plant colonization
Authors: Catford Jane A. , Dwyer John M. , Palma Estibaliz , Cowles Jane M. , Tilman David
Published: January 2020

Abiotic environmental change, local species extinctions and colonization of new species often co‐occur. Whether species colonization is driven by changes in abiotic conditions or reduced biotic resistance will affect community functional composition and ecosystem management. We use a grassland experiment to disentangle effects of climate warming and community diversity on plant species colonization. Community diversity had dramatic impacts on the biomass, richness and traits of plant colonists. Three times as many species colonized the monocultures than the high diversity 17 species communities (~30 vs. 10 species), and colonists collectively produced 10 times as much biomass in the monocultures than the high diversity communities (~30 vs. 3 g/m2). Colonists with resource‐acquisitive strategies (high specific leaf area, light seeds, short heights) accrued more biomass in low diversity communities, whereas species with conservative strategies accrued most biomass in high diversity communities. Communities with higher biomass of resident C4 grasses were more resistant to colonization by legume, nonlegume forb and C3 grass colonists, but not by C4 grass colonists. Compared with effects of diversity, 6 years of 3°C‐above‐ambient temperatures had little impact on plant colonization. Warmed subplots had ~3 fewer colonist species than ambient subplots and selected for heavier seeded colonists. They also showed diversity‐dependent changes in biomass of C3 grass colonists, which decreased under low diversity and increased under high diversity. Our findings suggest that species colonization is more strongly affected by biotic resistance from residents than 3°C of climate warming. If these results were extended to invasive species management, preserving community diversity should help limit plant invasion, even under climate warming.
Sensory lexicon and relationships among brown colour, saltiness perception and sensory liking evaluated by regular users and culinary chefs: a case of soy sauces
Authors: Wongthahan Peerapong , Sae‐Eaw Amporn , Prinyawiwatkul Witoon
Published: January 2020

This study was performed to develop lexicon to describe soy sauces using regular users (consumers) vs. culinary chefs, to perform product grouping using a free‐sorting task and to determine relationship among physicochemical properties (colour, %NaCl) and consumer perception of soy sauces. Both panels identified eighteen terms to describe soy sauces, of which eleven terms (light, medium and dark brown colour, weak, medium and strong saltiness, sweetness, saltiness–sweetness, tasty/umami, and soy sauce and fermented aroma) were similar. For culinary chefs, three distinctive soy sauce groups based on brown colour (light, medium and dark brown) were identified, while two groups (light and medium dark brown) for regular users. From free‐sorting maps, both panels associated brown colour intensity with saltiness expectation/perception. From PCA biplots, both panels shared some similarities for sensory liking (colour, saltiness, flavour, overall liking) for soy sauces. This study suggested that brown colour intensities affected saltiness expectation/perception and were used for product grouping for soy sauces.
Antibacterial activity of Osmunda japonica (Thunb) polysaccharides and its effect on tomato quality maintenance during storage
Authors: Liu Xiaochen , Zhang Xiuling , Zhang Xueting , Li Fengfeng , Tian Yaqin , Du Meiling , Zhao Hengtian , Shao Lingling
Published: January 2020

Tomatoes are rich in nutrients, yet they have a short shelf life and are prone to decay due to bacterial invasion. Polysaccharides extracted from Osmunda japonica (Thunb) were briefly characterised. The inhibitory effect of polysaccharides on nine kinds of common spoilage and pathogenic bacteria in tomatoes stored postharvest was studied, and the polysaccharides had broad‐spectrum antibacterial and antifungal activities against many tested strains. The minimum inhibitory concentrations (MICs) and the minimum bactericidal (fungicidal) concentrations (MBCs) were determined, and the lowest MBC against Bacillus cereus was 0.15 g L−1. Various concentrations of an O. japonica (Thunb) polysaccharide (OP) solution were sprayed onto ordinary preservation paper, which then distinctly maintained tomato freshness. OP delayed vitamin C (VC) and titratable acid decreases and increased respiratory intensity in a dose‐dependent manner, reducing malondialdehyde accumulation. The tomatoes could be stored for 30 day at 25 ± 1 °C. OP has potential as a safe, nontoxic natural plant preservative.
Regulatory SNP rs5743417 impairs constitutive expression of human β‐defensin 1 and has high frequency in Africans and Afro‐Americans
Authors: Cruz Díaz Luis Antonio , Gutiérrez Ortega Abel , Chávez Álvarez Rocío del Carmen , Velarde Félix Jesús Salvador , Prado Montes de Oca Ernesto
Published: January 2020

The prediction of regulatory single nucleotide polymorphisms (rSNPs) in proximal promoters of disease‐related genes could be a useful tool for personalized medicine in both patient stratification and customized therapy. Using our previously reported method of rSNPs prediction (currently a software called SNPClinic v.1.0) as well as with PredictSNP tool, we performed in silico prediction of regulatory SNPs in the antimicrobial peptide human β‐defensin 1 gene in three human cell lines from 1,000 Genomes Project (1kGP), namely A549 (epithelial cell line), HL‐60 (neutrophils) and TH1 (lymphocytes). These predictions were run in a proximal pseudo‐promoter comprising all common alleles on each polymorphic site according to the 1,000 Genomes Project data (1kGP: ALL). Plasmid vectors containing either the major or the minor allele of a putative rSNP rs5743417 (categorized as regulatory by SNPClinic and confirmed by PredictSNP) and a non‐rSNP negative control were transfected to lung A549 human epithelial cell line. We assessed functionality of rSNPs by qPCR using the Pfaffl method. In A549 cells, minor allele of the SNP rs5743417 G→A showed a significant reduction in gene expression, diminishing DEFB1 transcription by 33% when compared with the G major allele (p‐value = .03). SNP rs5743417 minor allele has high frequency in Gambians (8%, 1kGP population: GWD) and Afro‐Americans (3.3%, 1kGP population: ASW). This SNP alters three transcription factors binding sites (TFBSs) comprising SREBP2 (sterols and haematopoietic pathways), CREB1 (cAMP, insulin and TNF pathways) and JUND (apoptosis, senescence and stress pathways) in the proximal promoter of DEFB1. Further in silico analysis reveals that this SNP also overlaps with GS1‐24F4.2, a lincRNA gene complementary to the X Kell blood group related 5 (XKR5) mRNA. The potential clinical impact of the altered constitutive expression of DEFB1 caused by rSNP rs5743417 in DEFB1‐associated diseases as tuberculosis, COPD, asthma, cystic fibrosis and cancer in African and Afro‐American populations deserves further research.
Incidence and risk factors associated with pressure injury in patients with traumatic brain injury
Authors: Osis Sibila Lilian , Diccini Solange
Published: January 2020

Aim

To identify the prevalence of pressure injury in patients diagnosed with traumatic brain injury and analyse the risk factors involved during hospitalization.

Methods

This was a prospective study evaluating patients who were diagnosed with traumatic brain injury between November 2013 and September 2014. Patient characteristics, clinical and metabolic factors and therapeutic interventions, were evaluated within 30 days of hospital admission.

Results

Most of the 240 patients included in the study were male, young, and non‐Caucasian. The incidence of pressure injury was 18.8%. In terms of severity classification, the incidence of pressure injury was 2.7%, 23.2%, and 42.6% in mild, moderate, and severe traumatic brain injury, respectively. Pressure injury development was more likely in the first 10 days of hospitalization. A moderate or severe traumatic brain injury classification, the use of noradrenaline, and older age were pressure injury risk factors. The presence of pressure injury was associated with mortality within 30 days of hospitalization (P < .001).

Conclusion

The incidence of pressure injury was high in patients diagnosed with traumatic brain injury, especially in those whose injury was classified as severe. Older age, noradrenaline use, and a classification of moderate or severe traumatic brain injury were identified as pressure injury risk factors.
Groundwater Management: Efficiency and Equity Considerations
Authors: Feinerman Eli
Published: January 2020

Groundwater has the characteristics of commonly owned property, and its use is likely to be inefficient in the absence of regulation. Several management tools can be used to regulate groundwater withdrawals, with no one tool dominating the others in terms of efficiency of water use. However, the welfare distributional effects of various management schemes on individual users who vary in their derived demands for groundwater might be quite substantial, and different users may find considerably different schemes attractive.

The equity problems associated with the division of management benefits may dominate the decisions about support of or opposition to groundwater management, and hence they must be undertaken with considerable care and resolved by consensus among users. Although the negotiations are expected to be extensive and complicated, there is a substantial basis for agreement because all users stand to gain; the question is, who will gain the most?
Link between Agricultural Assistance and International Trade
Authors: Houck James P.
Published: January 2020

This paper investigates a central part of the argument that agricultural assistance by the United States to developing nations leads to diminished export markets for U.S. farmers. A sizeable cross section of low‐income and lower‐middle‐income nations is used to provide statistical analyses of: (1) the link between agricultural productivity and economic performance, and (2) the link between economic performance and agricultural imports. The results show that a reasonably strong case can be made for the idea that advances in agricultural productivity are associated with long‐run increases in imports of cereals and other agricultural products by less wealthy nations. The connection comes via the positive income effect of general economic development. For these countries, investments in agricultural development through successful assistance are not detrimental to U.S. farm export interests in the long run. They are generally beneficial.

For middle‐income nations, the case is less clear and more controversial. However, nothing in the cross‐section data used suggests that farm productivity improvements in these nations is systematically threatening to U.S. agricultural trade in the long run.
Collateral, Guaranties and Rural Credit in Developing Countries: Evidence from Asia
Authors: Feder Gershon , Onchan Tongroj , Raparla Tejaswi
Published: January 2020

The paper reviews the theory of the impact of loan collateral, and in particular land collateral, in institutional and non‐institutional rural credit markets. Evidence from three Asian developing countries is presented, showing extensive use of land collateral among institutional lenders in countries where such collateral is legal. The use of land collateral is more common than other forms of security, except in places where legal inhibitions on mortgaging agricultural land exist. Non‐institutional lenders are less inclined to use land collateral. However, lenders who do not have links to borrowers in matters other than finance are more likely to use loan securities. Estimates of instutional credit supply and demand in rural Thailand confirm that the pledging of land collateral affects the supply of credit more than group guaranty. It is also shown that larger farmers are more likely to utilize land collateral. The conclusion is that land collateral is preferred by instutional lenders as it reduces creditworthiness assessment costs. Attempts to ban or limit collateral use by decree are motivated by equity considerations, but they will cause loss of efficiency. Simplification of ownership verification and other policies reducing the transaction cost of collateral pledging will mitigate the negative equity implications of collateral.
Technological Change in Illinois Agriculture, 1982‐1984
Authors: Grabowski Richard , Kraft Steven , Mehdian Seyed , Pasurka Carl
Published: January 2020

This paper has two main purposes: (1) to develop a method for measuring the extent and bias of technical change which involves the use of non‐parametric production frontiers and does not require information on prices or factor shares; (2) to apply this method to individual farm data drawn from a sample of Illinois grain farms for the years 1982 and 1984. The results indicate that technical innovation is land using in nature and that the rate of technical change is related to the size of farm.
Market Price Response of World Rice Research
Authors: Hayami Yujiro , Kikuchi Masao , Morooka Kazuko
Published: January 2020

Using the total number of research publications as a proxy, the output of rice research in the world is estimated to be highly responsive in the short run to price fluctuations in the international rice market. The results suggest a danger of the inducement mechanism of public investment in the agricultural production infrastructure being misguided by cyclical price changes, thereby leading to recurrent food shortages and oversupplies in a cobweb‐like manner.
Sense and Sustainability: Sustainability as an Objective in International Agricultural Research
Authors: Lynam John K. , Herdt Robert W.
Published: January 2020

This paper first discusses how to use sustainability as a criterion by which to evaluate agricultural research, then illustrates the difficulties inherent in applying the criterion and finally draws implications for international agricultural research. Seven propositions relating to sustainability are stated. Agricultural researchers are urged to (a) recognize the importance of the sustainability of agricultural systems. (b) devise appropriate ways to measure sustainability, (c) empirically examine the sustainability of some well‐defined cropping or farming systems, (d) define the externalities that exist in such systems, and (e) develop methods to measure those externalities.
Regional Cooperation in the Use of Irrigation Water: Efficiency and Income Distribution
Authors: Yaron D. , Ratner A.
Published: January 2020

The paper presents an analysis of the economic potential of regional cooperation in water use in irrigation under conditions characterized by a general trend of increasing salinity. Income maximizing solutions for the region are derived and the related income distribution schemes are solved for, with the aid of cooperative game theory algorithms and shadow cost pricing. Distinction is made between distribution policies with and without side payments. The reasonableness and the acceptability of these schemes is later critically evaluated. The Nash‐Harsanyi approach seems to be the most appropriate for the conditions studied.
Changes needed in agricultural policy for female‐headed farm families in tropical Africa
Authors: Due Jean M. , Magayane F.
Published: January 2020

The decline in per‐capita agricultural production has been reversed somewhat in tropical Africa by the structural adjustment programs which have increased producer prices, liberalized marketing and devalued currencies. But the 30% of smallholder farm households which are female‐headed will not be assited much due to their special constraints of shortages of labor and credit, lack of extension visits and appropriate labor‐saving technologies. For these households, the authors argue, improved extension services, credit for agricultural inputs, small ruminant animals and poultry, labor‐saving devices and craft inputs will be necessary to increase their incomes and levels of living.
An application of optimal control theory to agricultural policy analysis
Authors: Ennew C.T. , Rayner A.J. , Reed G.V. , White B.
Published: January 2020

Since the early 1970s there has been interest in the application of optimal control theory to the management of economic systems. Specifically, optimal control theory prescribes policy strategies which optimise a quantifiable policy preference function subject to market equilibrium conditions. Problems of this kind have been identified among agricultural markets and this paper aims to illustrate the application of optimal control theory to the British potato market. The paper takes evidence from policy makers to derive target values for the producer price, imports, and the changes in the quota area from year to year. The constraints on optimisation are specified in terms of a partial equilibrium econometric model which specifies, demand, supply and trade relationships. The policy preference function is specified as a quadratic and a ‘revealed preference approach’ is employed to estimate the parameters which penalise market equilibria which over or under‐shoot policy targets. The resulting optimal control problem is minimised by a dynamic programming routine. The results suggest that policy makers may benefit from taking dynamic effects directly into account when formulating policy strategies.
An Analysis of U.S. Aggregate Output Response by Farm Size
Authors: Henneberry Shida Rastegari , Tweeten Luther , Nainggolan Kaman
Published: January 2020

Past empirical evidence on supply response by size of farm in the U.S.A. provides no clear basis to conclude that supply elasticities vary systematically with farm size. In this paper, the central hypothesis that no systematic relationship exists between production response to price and size of farm is rejected. U.S. farms are disaggregated into nine economic size categories and own‐price supply elasticities are measured for per farm and total agricultural output. Empirical results from this study suggest that supply response does vary systematically by farm size, with smaller farms exhibiting greater elasticities than midsized farms.
Production and uses of subject‐matter research in federal service: observations from research on Farmer Mac
Authors: Hiemstra Stephen W.
Published: January 2020

Rapid institutional innovation in the 1980's has led to problems that exceed the scope of research normally assumed by individual researchers. During such periods of rapid change, subject‐matter research may be particularly useful. This paper reviews research on the Federal Agricultural Mortgage Corporation (Farmer Mac) and examines its role in the policy debate.
The zip (postal) code difference: methods to improve identification of rural subgroups
Authors: de la Torre Adela , Fickenscher Kevin , Luft Harold
Published: January 2020

Over the past decade national policymakers have grappled with the increasingly difficult issue of implementing programs which sustain the viability of the rural health care system. The set of problems that are of major concern to these decisionmakers include: (1) the shifts in the utilization patterns away from the rural health care delivery system; (2) the impact of modification in the health care reimbursement system which disproportionately favors urban health systems; and, (3) the continuing difficulty in affecting the disproportionate supply of health providers in urban areas compared to rural settings.

The complex nature of health services research demands a multidisciplinary approach especially on sociocultural problems such as rural health delivery. Effective analysis in health care crosses many disciplinary boundaries such as medicine, nutrition, economics, sociology, and public health among others disciplines. A major concern to many of these rural health research analysts is the ad hoc treatment of the rural populace in federal and state health policy decisionmaking. The key to understanding the variance in treatment of rural health can be appreciated by reviewing the accuracy of rural definitions.

In the present study, a refined rural definition is proposed which will assist research analysts in providing greater information on the distribution of rural health care services. A preliminary analysis of the proposed definitions indicates that a more precise measurement of rural provides greater accuracy in determining the medical needs of rural areas.

Adaptation of the concept will benefit the decisionmaking process through improvements in the methodological approach to rural health research. State legislators, regional and state planning agencies, federal funding agencies, foundations, and other programs involved in support of rural life program will be better able to assess the impact of programs through use of the new definition. Finally, a refined typology for rural will also effect other research endeavors and appears to be generalizable to research on other pertinent rural delivery issues such as transportation, education, and regional planning.
Food subsidies and market interdependence: the case of the Moroccan soft wheat subsidy
Authors: Azzam Azzeddine M.
Published: January 2020

Among the several propositions advanced to explain the rising cost of subsidizing soft wheat production and consumption in Morocco are the indirect effects emanating from related markets, namely the hard wheat and barley markets. A three‐sector supply‐demand model, described in this paper, was used to estimate the direct and indirect (induced) effects on government cost of changes in the soft wheat subsidy. The results show that virtually all the indirect effects come from the soft wheat market itself. The indirect effects emanating from the related markets are negligible.
Pests and pesticides, risk and risk aversion
Authors: Pannell David J.
Published: January 2020

Theoretical and applied literature on risk in decision making for agricultural pest control is reviewed. Risk can affect pesticide decision making either because of risk aversion or because of its influence on expected profit. It is concluded that risk does not necessarily lead to increased pesticide use by individual farmers. Uncertainty about some variables, such as pest density and pest mortality, does lead to higher optimal pesticide use under risk aversion. However, uncertainty about other important variables, such as output price and yield, leads to lower optimal levels of pesticide use. Neglect of these variables in most studies has led to the false assumption that pesticides are always risk‐reducing inputs. Furthermore, there is evidence that, in general, the pesticide dosage which maximises expected profit is lower under risk than under certainty. Depending on the balance of forces to increase and decrease pesticide use under risk, in many circumstances the net effect of risk on optimal decision making for pest control may be minimal. The effect on risk of information about pest density and other variables (as in integrated pest management programmes) is discussed. Evidence on this issue is mixed. A range of analytical techniques for analysing risk in pest control is reviewed. Throughout the paper, gaps in the existing literature are identified.
Size and industry effects in the performance of agricultural cooperatives
Authors: Lerman Zvi , Parliament Claudia
Published: January 2020

The objective of this study is to determine if there are important size and industry effects on financial performance of agricultural cooperatives. The performance of 43 dairy, food, grain, and farm supply cooperatives in the U.S. was analyzed over the period 1970‐1987 using financial ratios derived from accounting data. The analysis revealed significant size and industry effects. Large regional cooperatives are more efficient in utilizing their assets to generate sales, while small regional cooperatives have higher profitability. The findings suggest that the emphasis on growth may not always produce beneficial results among agricultural cooperatives. Among the four industries studied, the dairy regional cooperatives appear to be the strongest performers, while the food marketing cooperatives are characterized by the lowest performance measures. Since both dairy and food cooperatives engage in value‐added processing, this difference in performance makes it difficult to reach clear conclusions about possible advantages of disadvantages or vertical integration relative to traditional cooperative activities. Trend analysis indicates that the profitability of the agricultural cooperatives in all industry and size categories declined in response to the downturn in U.S. agriculture after 1980. While the decline in profitability was at similar rates for both large and small cooperatives, the variation of efficiency and leverage was in opposite directions. Large cooperatives may be expected to continue improving their asset utilization without relative improvement in profitability, and increasing the level of their debt in relation to equity.
An econometric analysis of rice consumption in the People's Republic of China
Authors: Peterson E. Wesley F. , Jin Lan , Ito Shoichi
Published: January 2020

Rice is the most important staple food in the People's Republic of China (PRO. In many Asian countries rice appears to have become an inferior good, with income increases leading to declines in per capita consumption as other food products are substituted for rice. In this study, human rice consumption is analyzed with a model that allows income elasticities to vary with income levels. An additional equation accounting for rice disappearance as seed, livestock feed, industrial uses and exports is also estimated. The results of the analysis indicate that rice has become an inferior good in China and per capita consumption is likely to decline in the future. Population growth and the growing use of rice for other purposes means that total rice disappearance will continue to increase although at a rate that is slower than has historically been the case. The predicted changes in rice consumption will create pressures to adjust production and trade patterns for rice as well as other agricultural products.
A stochastic dynamic programming framework for weed control decision making: an application to Avena fatua L.
Authors: Pandey Sushil , Medd R.W.
Published: January 2020

This paper develops a stochastic multi‐period decision model to analyse a continuous wheat cropping system infested by wild oats (Avena fatua L.), in southern Australia. The multi‐period solutions is obtained by employing a dynamic programming model in conjunction with a bioeconomic simulation model. An empirically estimated dose response function is used to derive the optimal herbicide rate. Uncertainties due to environmental effects on the performance of herbicide and crop yields are modelled and optimal decision rules derived. The results indicate that substantial economic gains can be realised if herbicide dose decisions are taken by considering future profit effects of current decisions, as opposed to the more common approach of only considering the current‐period effect.
Development of township enterprise and alleviation of the employment problem in rural China
Authors: Zhou Zhang Y. , Dillon John L. , Wan Guang H.
Published: January 2020

In contrast to the situation in western countries at the time of their industrialization, it has been and still is impossible for rural labour in China to move to the urban sector for employment. For this and other reasons, including shortage of arable land and population growth, lack of employment opportunities continues to be a serious problem in rural China. This article discusses the development of township enterprise in rural areas and its role in the alleviation of China's rural employment problem. It is suggested that the further development of township enterprise should be an important element of China's development strategy.
Allocable fixed inputs as a cause of joint production: an empirical investigation
Authors: Leathers Howard D.
Published: January 2020

Leathers (1991) shows that while the existence of allocable fixed inputs can cause joint production (as in Shumway, Pope and Nash, 1984), it will not necessarily lead to joint production. The extent to which allocable fixed inputs cause joint production in agriculture is an empirical question. This paper offers an empirical answer. By estimating a short‐run joint cost function, it is possible to identify levels of outputs for which joint production may be optimal in the short run but not in the long run. Only in these output regions will there be jointness caused by allocable fixed inputs. For the data in this paper (160 Wisconsin farms), these output regions are very small; thus allocable fixed inputs do not appear to be an important cause of jointness for these farms. Technical causes of jointness appear to be a significant cause of joint production.
A critical assessment of the political preference function approach in agricultural economics
Authors: von Cramon‐Taubadel Stephan
Published: January 2020

The policy preference function (ppf) approach has become popular with economists seeking to explain the origin of government policies. In this paper, a distinction between positive and normative work with the ppf concept is made. Positive work is shown to suffer from a variety of shortcomings including the misspecification of traditional ppfs and the failure to consider the importance of institutions, constraints and the interaction between different commodity policies. These weaknesses are reflected in the counter‐intuitive results of a simple ppf model designed to reflect the interaction between the EC's wheat and barley policies. Furthermore, it is demonstrated that ppf weights change as a result of both political preferences and market parameters. Hence, changes in ppf weights cannot be attributed to changes in preferences alone. Tests of the axioms of revealed preference theory are used to demonstrate that even though ppf weights derived for the EC's wheat and barley markets have fluctuated considerably since the early 1970s, we are not able to conclude that there has been a shift in political preferences. The paper concludes with some comments about the use of ppfs in a normative framework. The underlying assumption that policy‐makers optimise seems, not surprisingly, often to lead practitioners to the conclusion that observed policies are not so bad after all. Economists should also beware of the tendency to overlook possible differences between the ppf and the social welfare function.
Nearly optimal linear programming as a guide to agricultural planning
Authors: Jeffrey Scott R. , Gibson Ron R. , Faminow Merle D.
Published: January 2020

Linear programming has long been used as a tool in agricultural planning. This paper presents and discusses a technique that can be used in conjunction with linear programming to evaluate ‘nearly optimal’ solutions. This technique is referred to as Nearly Optimal Linear Programming or Modelling to Generate Alternatives (MGA). MGA allows planners to incorporate important objectives that are difficult to include in a mathematical model by identifying and evaluating alternative ‘nearly optimal’ solutions. Some of these alternative solutions may be consistent with the goals or objectives of decision makers.

To date, MGA has received little use in addressing agricultural planning problems. A micro‐level application of MGA, concerning a dairy ration formulation problem, is presented to demonstrate the relevance of MGA to agricultural planning by decision makers. Within this application, the use of MGA to complement and enhance normal linear programming analysis is also discussed.
Demand for cereal grains in Asia: the effect of urbanization
Authors: Huang Jikun , David Cristina C.
Published: January 2020

This paper analyzes the effects of urbanization on demand for cereal grains – rice, wheat, and coarse grains – in nine Asian countries. A complete demand system (Almost Ideal Demand System in linear form) is estimated in two stages based on aggregate time series data from 1960 to 1988.

In the high‐income countries, i.e. Japan and South Korea, urbanization was observed to significantly reduce demand for cereal grains. In the lower‐income countries, demand for cereal grains cither increased or remained the same with urbanization.

Among cereal grains, urbanization has had negative effects on demand for rice and coarse grains, but consistently positive effects on demand for wheat. Only Japan and Thailand among the countries studied have negative income elasticities of demand for total cereal grains and for rice in particular. Hence, rice remains a necessity and a normal good in most Asian countries.

Previous estimates of income elasticities of rice based on time‐series aggregate data tend to be lower than those based on cross‐section household level data. When urbanization is explicitly specified in the demand model, the estimates of income elasticities from time‐series data turn out to be consistent with those from cross‐section data.
Economic returns to cowpea research, extension, and input distribution in Senegal
Authors: Schwartz Lisa A. , Sterns James A. , Oehmke James F.
Published: January 2020

This paper calculates the rate of return to a set of cowpea research, extension and distribution projects in Senegal to be between 31% and 92%. The results show that a modestly funded program on a secondary crop can be successful. They also indicate that programs may increase their effectiveness by addressing specific household needs – in this case, by focusing on short‐cycle varieties that provide food during the hunger season prior to the traditional harvest.
Estimation of stochastic frontier production functions with time‐varying parameters and technical efficiencies using panel data from Indian villages
Authors: Battese G.E. , Tessema G.A.
Published: January 2020

A stochastic frontier production function with time‐varying technical efficiencies is estimated using panel data from ICRISAT's Village Level Studies in three Indian villages. Given the specifications of a linearized version of a Cobb–Douglas stochastic frontier production function with coefficients which are a linear function of time, the hypothesis that the traditional response function is an adequate representation of the data is accepted for only one of the three villages. The hypothesis of time‐invariant technical inefficiencies is not rejected for one of the two villages for which significant technical inefficiencies exist. The hypothesis of time‐invariant elasticities of the input variables is rejected for two of the three villages. Further, the hypothesis that hired and family labour are equally productive is accepted in only one of the three villages.

The technical efficiencies of individual farms exhibited considerable variation in the two villages with either time‐invariant or time‐varying technical efficiencies.
Agricultural policy adjustments in the Korean rice economy
Authors: Kwon Yong Dae , Yamauchi Hiroshi
Published: January 2020

A political preference function is used to endogenize government actions in a simultaneous equation model for South Korean rice policy. The effects of economic changes on rice pricing decisions through estimated political weights are tested to improve our understanding of policy adjustments in that country and open the way for further research in East Asia.
Evaluating alternative price expectation models for multiproduct supply analysis
Authors: McIntosh Christopher S. , Shumway C. Richard
Published: January 2020

Neoclassical economic theory provides an important conceptual framework for the analysis of agricultural production. Theory provides little guidance, however, in the actual specification of empirical models. This paper applies an integrated approach for choosing between price expectation mechanisms in a multiple‐equation model when the alternatives are non‐nested. Nine alternative specifications of market price and policy information are developed. Price forecasting accuracy, non‐nested tests of hypotheses, and out‐of‐sample predictive accuracy are examined for agricultural production in Iowa. The results call into question the reliability of using forecasting accuracy as the sole guide to selecting a price expectation proxy.
Impact of the US–EC price war on major wheat exporters' shares of the Chinese market
Authors: Ahmadi‐Esfahani Fredoun Z. , Jensen Paul H.
Published: January 2020

China is both the world's largest producer and consumer of wheat. In an attempt to gain a larger slice of the important Chinese market, both the European Community and the United States have offered China subsidised wheat. In addition, other exporters have offered attractive credit arrangements to China. The objective of this paper is to measure the overall impact of these policies on each exporter's share of the Chinese market. To that end, an improved version of the constant market shares model is applied to data on Chinese wheat imports in the 1980's. The results indicate that the United States has been outperforming the other exporters since subsidised US wheat sales were authorised for China in 1987. The implications of the analysis for the smaller exporters and international wheat trade are discussed.
Sustaining growth in agriculture: a quantitative review of agricultural research investments
Authors: Anderson Jock R. , Pardey Philip G. , Roseboom Johannes
Published: January 2020

Growth in agriculture depends on many things but one of the most important is investment in agricultural research. Decision making in the agricultural research policy area can only be aided by access to better information. This article overviews a recent endeavor to move policy dialogue beyond merely qualitative impressions towards a process that is underpinned with new and cogent data. The data used have been assembled at ISNAR in a manner designed to make comparisons both over time and between countries more valid than has been the case in the past. The comparisons thus possible reveal considerable diversity both between countries and between broad regional aggregations. Also illuminated here are issues related to the commodity orientation, capital and labor intensity, and size and scope of particular national programs.
Resource supplies and changing world agricultural comparative advantage
Authors: Tobey James A. , Chomo G.V.
Published: January 2020

This paper advances consideration of the Heckscher–Ohlin (H‐O) theory of comparative advantage to agriculture in a dynamic setting. The dynamic relationship among trade flows, resource supplies, and factor contents is studied. The view that special circumstances in the agricultural sector render the H‐O theory inapplicable as a guide to agricultural trade is challenged. Consistent with the H‐O theory, the results suggest that changing world patterns of resource abundance are an important explanation of the evolving structure of world trade in agriculture commodities.
International trade in a differentiated good: Trade elasticities in the world rice market
Authors: Agcaoili‐Sombilla Mercedita C. , Rosegrant Mark W.
Published: January 2020

In many previous rice trade models, the commodity has been regarded as a homogeneous product. However, homogeneity is not an appropriate assumption, given the various types of rice that are traded and consumed. Parameters estimated from these models, therefore, do not reflect the real world market for rice and, hence, may mislead decision makers who use the results for policy evaluation purposes. This study uses an Armington approach to model the world rice trade as a differential good market and to derive trade elasticity parameters.