bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of customization of master gutta‐percha cone on apical control of root filling using different techniques: an ex vivo study
Authors: Van Zyl S. P. , Gulabivala K. , Ng Y.‐L.
Published: August 2005

Aims  (i) To compare the prevalence of extrusion of root filling material when placed using different root filling techniques, with or without customization of the master gutta‐percha (GP) cone; and (ii) to investigate the effects of some factors influencing root filling extrusion and presence of voids.

Methodology  A total of 180 roots were selected, prepared and randomly allocated to three groups. Five general dental practitioners performed the root fillings; each filled one group of roots (n = 60) using each of three techniques; ‘cold lateral compaction’ (n = 20), ‘warm vertical compaction’ (n = 20) and ‘continuous‐wave’ (n = 20) techniques. For each obturation technique, the master GP cone was customized using chloroform in 10 samples. Two groups of the roots were recycled to allow all five operators to fulfill their remit. Two observers, blind to operator and obturation technique, examined the radiographs (master apical file, post‐obturation) to determine the presence of root filling extrusion and voids within the apical 5 mm, independently. Root filling extrusion was also confirmed by direct inspection of the root apex after obturation. The data were analysed using logistic regression models.

Results  A total of 300 root fillings were performed; nine were excluded from the analysis. Most of the root fillings (80%, n = 233) were placed within 0.5 mm of the working length; only 20% (n = 58) were placed >0.5 mm beyond the working length. The odds of prevalence of extrusion (>0.5 mm) were significantly reduced by about 50% when cold lateral compaction or customization of GP were used. One operator produced 2.5 times more extruded root fillings than others. Curvature & length of root canal, apical size of prepared canal, as well as operator's preferred obturation technique had no significant influence on the prevalence of extrusion. Customization of GP was the sole factor to significantly reduce the prevalence of voids within the apical 5 mm of working length.

Conclusions  Root filling extrusion was significantly influenced by ‘operator’ and was reduced by cold lateral compaction and customization of the master cone. Customization of master cone was the only factor that reduced voids apically.
Effect of E. faecalis on the release of serine proteases elastase and cathepsin G, and collagenase‐2 (MMP‐8) by human polymorphonuclear leukocytes (PMNs)
Authors: Reynaud af Geijersstam A. , Sorsa T. , Stackelberg S. , Tervahartiala T. , Haapasalo M.
Published: August 2005

Aim  To measure the release of hydrolytic enzymes [elastase, cathepsin G and collagenase‐2 (MMP‐8)] from human polymorphonuclear leukocytes (PMNs) during interaction with strains of Enterococcus faecalis isolated from endodontic infections.

Methodology  Six E. faecalis strains isolated from treatment resistant cases of apical periodontitis were included in the study. Overnight cultures of the microbes were used for the experiments. PMNs were isolated using the Ficoll Paque technique, and their vitality was assessed throughout the experiments by the Trypan Blue exclusion test. A known amount of microbes and PMNs were mixed in PBS at +37 °C in air, and the release of elastase, cathepsin G and MMP‐8 was measured at 0, 20, 60 and 120 min after initiation of incubation. The activities of elastase and cathepsin G were analysed by spectrophotometer assays using specific synthetic peptide substrates, and MMP‐8 by western immunoblotting quantitated by computer densitometry. PMNs incubated in buffer without any added microbes served as negative controls, cells incubated with 5 ng mL−1 phorbol myristic acetate (PMA) served as a positive control. The 95% confidence interval was used to compare the relative amount of elastase and cathepsin G released from the samples.

Results  One E. faecalis strain induced a similar or higher elastase, cathepsin G and MMP‐8 release than the positive control, whereas the other five strains induced only moderate or no release of the three enzymes examined as compared with the negative and positive controls. Western immunoblot revealed that released MMP‐8 had molecular sizes of 60 and 75 kDa representing active and latent forms of MMP‐8. In addition, >110 kDa high molecular size and a fragmented 20–30 kDa MMP‐8 species could be observed.

Conclusions  The majority of the E. faecalis strains induced little or no release of hydrolytic enzymes from the PMN cells. The finding may partly explain the clinical observation that root canal infections dominated by E. faecalis are usually symptom free.
Response and adaptation of different methanotrophic bacteria to low methane mixing ratios
Authors: Knief Claudia , Dunfield Peter F.
Published: August 2005

Described genera of methanotrophic bacteria are present in most upland soils, but it is not known whether these are sufficiently oligotrophic to oxidize methane at its trace atmospheric mixing ratio of 1.75 ppmv. Members of the genera Methylocystis, Methylosinus, Methylocaldum and Methylobacter were isolated from different upland soils and compared with type strains for growth and activity under low methane mixing ratios. The specific affinity (a0s) varied by about one order of magnitude among different methanotrophs. It was highest in some Methylocystis spp., suggesting that these were the most oligotrophic. In direct tests, the threshold mixing ratio of methane required by most methanotrophs for growth ranged from 100 to greater than 1000 ppmv. However, two Methylocystis strains grew at only 10–100 ppmv of methane and one oxidized atmospheric methane for >  3 months with little or no decline in the absolute rate. The results show that some cultivated methanotrophic bacteria are much more oligotrophic than others, and may contribute to atmospheric methane oxidation in soils. However, it is likely that these need additional energy sources for long‐term survival, and that uncultivated groups of methanotrophic bacteria are primarily responsible for the process in soils possessing high methane oxidation rates.
Evolutionary innovation: a bone‐eating marine symbiosis
Authors: Goffredi Shana K. , Orphan Victoria J. , Rouse Greg W. , Jahnke Linda , Embaye Tsegeria , Turk Kendra , Lee Ray , Vrijenhoek Robert C.
Published: August 2005

Symbiotic associations between microbes and invertebrates have resulted in some of the most unusual physiological and morphological adaptations that have evolved in the animal world. We document a new symbiosis between marine polychaetes of the genus Osedax and members of the bacterial group Oceanospirillales, known for heterotrophic degradation of complex organic compounds. These organisms were discovered living on the carcass of a grey whale at 2891 m depth in Monterey Canyon, off the coast of California. The mouthless and gutless worms are unique in their morphological specializations used to obtain nutrition from decomposing mammalian bones. Adult worms possess elaborate posterior root‐like extensions that invade whale bone and contain bacteriocytes that house intracellular symbionts. Stable isotopes and fatty acid analyses suggest that these unusual endosymbionts are likely responsible for the nutrition of this locally abundant and reproductively prolific deep‐sea worm.
The molecular diversity of freshwater picoeukaryotes from an oligotrophic lake reveals diverse, distinctive and globally dispersed lineages
Authors: Richards Thomas A. , Vepritskiy Alexey A. , Gouliamova Dilnora E. , Nierzwicki‐Bauer Sandra A.
Published: August 2005

The recent discovery of a diverse phylogenetic assemblage of picoeukaryotes from environments such as oceans, salt marshes and acidic habitats, has expanded the debates about the extent and origin of microbial eukaryotes. However, the diversity of these eukaryote microorganisms, that overlap bacteria in size, and their environmental and biogeographical ubiquity remains poorly understood. Here we survey picoeukaryotes (microbial eukaryotes of 0.2–5 µm in size) from an oligotrophic (nutrient deficient) freshwater habitat using ribosomal RNA gene sequences. Three taxonomic groups the Heterokonta, Cryptomonads and the Alveolata dominated the detected diversity. Most sequences represented previously unsampled species, with several being unassignable to known taxonomic groups and plausibly represent new or unsampled phyla. Many freshwater phylogenetic groups identified in this study appeared unrelated to picoeukaryotic sequences identified in marine ecosystems, suggesting that aspects of eukaryote microbial diversity are specific to certain aquatic environments. Conversely, at least five phylogenetic clusters comprised sequences from freshwater and globally dispersed and often contrasting environments, supporting the concept that a number of picoeukaryotic lineages are widely distributed.
Coupling 16S‐ITS rDNA clone libraries and automated ribosomal intergenic spacer analysis to show marine microbial diversity: development and application to a time series
Authors: Brown Mark V. , Schwalbach Michael S. , Hewson Ian , Fuhrman Jed A.
Published: August 2005

We outline an approach to simultaneously assess multilevel microbial diversity patterns utilizing 16S‐ITS rDNA clone libraries coupled with automated ribosomal intergenic spacer analysis (ARISA). Sequence data from 512 clones allowed estimation of ARISA fragment lengths associated with bacteria in a coastal marine environment. We matched 92% of ARISA peaks (each comprising > 1% total amplified product) with corresponding lengths from clone libraries. These peaks with putative identification accounted for an average of 83% of total amplified community DNA. At 16S rDNA similarities < 98%, most taxa displayed differences in ARISA fragment lengths > 10 bp, readily detectable and suggesting ARISA resolution is near the ‘species’ level. Prochlorococcus abundance profiles from ARISA were strongly correlated (r 2 = 0.86) to Prochlorococcus cell counts, indicating ARISA data are roughly proportional to actual cell abundance within a defined taxon. Analysis of ARISA profiles for 42 months elucidated patterns of microbial presence and abundance providing insights into community shifts and ecological niches for specific organisms, including a coupling of ecological patterns for taxa within the Prochlorococcus, the Gamma Proteobacteria and Actinobacteria. Clade‐specific ARISA protocols were developed for the SAR11 and marine cyanobacteria to resolve ambiguous identifications and to perform focused studies. 16S‐ITS data allowed high‐resolution identification of organisms by ITS sequence analysis, and examination of microdiversity.
Hindrance for patient participation in nursing care
Authors: Sahlsten Monika J.M. , Larsson Inga E. , Plos Kaety A.E. , Lindencrona Catharina S.C.
Published: August 2005

The study's rationale: Patients’ influence in health care through participation, freedom of choice and information, is laid down in laws, national and local directives. In nursing care situations, the degree to which a patient participates depends on the nursing staff. Accordingly, hindrances for patient's participation during nursing care is an important question for the nursing profession.

Aims and objectives: The aim was to focus on Swedish Registered Nurses opinion of hindrances for patient participation in nursing care and to uncover the informants’ perspectives in depth.

Methodological design and justification: The study was limited to inpatient somatic care and has a qualitative approach. Data were collected through seven focus group interviews with 31 Registered Nurses from five hospitals. An analysis of the tape‐recorded interview material was made, combining elements of content analysis with aspects of the Grounded Theory approach.

Ethical issues and approval: The ethics of scientific work was followed. The participants gave informed consent. Verbal and written information was given as a guarantee that all information would be treated confidentially outside the focus group. Formal approval by ethical committee was not required according to national and local directives.

Results: Hindrance for patient participation in nursing care comprised three themes: Competence, Influence of significant others and Organization and work environment, and their seven underlying subthemes.

Conclusions: The study clarified factors, which individually or combined may be hindrance for patient participation in nursing practice. Professional nurses must be able to find a balance for their patients’ participation in nursing care activities through identification and coping with the hindrances. The three themes and seven subthemes here identified, can be used in patient care and its’ evaluation, like also quality assurance of care and work organization and in nursing education. For further development replication studies are needed, like additional studies of patients and significant others.
Swedish child health care in a changing society
Authors: Hallberg Ann‐Christine , Lindbladh Eva , Petersson Kerstin , Råstam Lennart , Håkansson Anders
Published: August 2005

Background:  Staff in Swedish child health care today feel a gap between policy and practice. By revealing the main lines in the development of child health care, we hoped to achieve a better understanding of the current trends and problems in today's Swedish child health care.

Methods:  A selection of official documents about the development of child health care during the period 1930–2000 was studied with the aid of discourse analysis.

Results:  Four discourses were identified, which serve as a foundation for a periodization of the development of child health care. In the first period the main task of child health care, alongside checking on the development of the child, was to inform and educate the mothers. During the second period health supervision became the crucial task, to identify risks and discover abnormalities and disabilities. The third period focused on the discussion concerning the identification of health‐related and social ‘risk groups’, and the work of child health care was increasingly geared to supervision of the parents’ care of their children. Parents were to be given support so that they could cope with their difficulties by themselves. During the current period child health care is increasingly expected to direct its work towards the child's surroundings and the family as a whole and is now explicitly defined as an institution that should strengthen parents’ self‐esteem and competence. The level of responsibility for the child's health changed gradually during the different periods, from public responsibility to parental responsibility. The focus of efforts in child health care was changed from being general in the first and second periods to general and selective in period three, and then gradually becoming selective again in period four. While control of the child's physical health was central during the first two periods, psychosocial health came into focus in the last two, along with the importance of supporting the parents to enable them to handle their difficulties by themselves.

Concluding remarks:  We noted that it was difficult to translate policy recommendations into practice. One reason was the shifting focus in child health care from the child's physical health to psychosocial problems which in itself meant a shift from descriptions of concrete and well‐defined duties to more abstract and general descriptions of tasks which are by definition open to interpretation. Another reason for the noted difficulty was the transition from unambiguously described measures in terms of paternalistic regulation to more participatory and at the same time more expansive definitions of roles and responsibilities.
Being in an alien world: Danish parents’ lived experiences when a newborn or small child is critically ill
Authors: Hall Elisabeth O.C.
Published: August 2005

Parents of critically ill small children have received quite a lot of attention in nursing and allied health literature. However, no documented studies were found from Danish paediatric or neonatal contexts. The aim of the study therefore was to identify Danish parents’ lived experiences during a newborn or small child's critical illness. The study was undertaken in a human caring perspective assuming that caring is primary and relational, and that persons are concerned when things matter to them. Thirteen parents were interviewed twice, and data were analysed following Van Manen's phenomenological methodology. The findings revealed that being a parent when a newborn or small child is critically ill resembled being in another world, alien from what they knew and had earlier experienced. The parents wanted to be close to the child, they were seeking for an understanding of what happened, and they felt inexperienced and insecure but at the same time they were attentive and vigilant. The sub‐themes that were more prominent were ‘a need to be there’, ‘What is going on?’, ‘being vigilant’, ‘being a spectator to your own life’, and ‘oscillating between hope and hopelessness’. The study implies that the staff needs to help the parents perceive some kind of meaning of what is going on, to instill hope despite not knowing the outcome, and to accept and respect the parents’ style of coping with stress and concern for their sick child.
Agricultural reforms in Central and Eastern Europe and the former Soviet Union Status and perspectives⋆
Authors: Csaki C.
Published: August 2005

The current status of the agricultural sector in Central and Eastern Europe and the former Soviet Union is described, in the context of reforms undertaken during the transition from a centrally planned economy to a market‐based one. Sectoral performance is analyzed, focussing especially on general trends in production, and emerging trading patterns. Five critical basic elements of reform are described, and a table is presented rating each country in the study on progress in completing each type of reform. Overall conclusions are presented, indicating that in each basic element of reform, the CEE countries have achieved considerably more success than those of the CIS. The paper concludes with a discussion of prospects for development in the region.
The external costs of pasture weed spread: an economic assessment of serrated tussock control
Authors: Jones R. E. , Vere D.T. , Campbell M.H.
Published: August 2005

The external cost associated with the spread of pasture weeds such as serrated tussock (Nassella trichotoma) is an important economic problem. This problem is complicated in many parts of south‐eastern Australia where low rainfall and low soil fertility prevent the economic viability of control of this weed through pasture improvement. A consequence of serrated tussock spread in this region has been calls for increased public intervention in its control. However, because there have been no attempts to measure the external costs of serrated tussock spread, one of the major economic grounds on which this activity might be justified has not been quantified. The purpose of this paper is to provide this information. A stochastic simulation model is developed to determine the size of the external cost associated with the spread of serrated tussock and to evaluate the economic benefits of a range of control scenarios. It is concluded that on low rainfall‐low soil fertility country the socially optimal control option for serrated tussock is to retire land from agriculture and re‐vegetate it with trees.
Allocation of time for meal preparation in a transition economy
Authors: Florkowski Wojciech J. , Moon Wanki , Resurrection Anna V.A. , Jordanov Jordan , Paraskova Pavlina , Beuchat Larry R. , Murgov Kolyo , Chinnan Manjeet S.
Published: August 2005

The decision of how much time to allocate to meal preparation is an endogenous variable to be determined by the opportunity cost of time, preference between market and nonmarket goods and leisure, and household production technology. Using consumer survey data collected in Bulgaria in 1997, this study measured the effect of household income on the amount of time allocated to meal preparation after controlling the effects of demographic, socio‐economic and other characteristics of households. We used the first‐hurdle dominance model to distinguish non‐meal preparers from meal preparers. Since the overall pattern of allocating time between market work, household activity and leisure in a particular country is likely to be conditional on the stage of its economic development, this study presents a unique opportunity to assess the rationality of the time allocation behavior of consumers in an economy in transition from a centrally‐planned to a market‐oriented system. Results showed that household income did not influence the decision of how much time to allocate to meal preparation. While the insignificant linkage between income and time allocation to meal preparation could be due to the differences in preference and household production technology. It can be also attributed to the legacy of four decades of a central‐planning system and underdeveloped food manufacturing and service industries. ©2000 Elsevier Science B.V. All rights reserved.
Impacts of WTO restrictions on subsidized EU sugar exports
Authors: Poonyth Daneswar , Westhoff Patrick , Womack Abner , Adams Gary
Published: August 2005

The study evaluates the impact of World Trade Organization (WTO) restrictions on the European Union (EU) sugar sector and the world sugar market. A small reduction in production quotas would be sufficient to satisfy the export subsidy limitations of the Uruguay Round agreement. Complete elimination of export subsidies by 2005 would require either a 10% reduction in production quotas or the combination of an 8% reduction in quotas and an 11% reduction in intervention prices. Higher world prices resulting from reduced EU exports would result in increased production of unsubsidized C‐sugar, with different impacts across EU member countries explained by differences in institutional pricing arrangements and marginal production costs.
Animal disease incidence and indemnity eradication programs⋆
Authors: Kuchler Fred , Hamm Shannon
Published: August 2005

There are many options for controlling the spread of animal diseases. Some diseases have been treated as public sector problems and many nations have tried to control disease spread by purchasing sick animals from farmers. Government agencies have purchased breeding stock that might transmit diseases. Government agencies have purchased animals that might otherwise have gone to the slaughterhouse, thereby keeping pathogens out of the food supply. Our hypothesis is that when it is not immediately obvious to farmers or private sector buyers which animals carry or transmit diseases, a government indemnity program's success is not assured. Instead, disease control depends on farmers' ability to respond to the relative prices they face. We examine the incentives created by prices (indemnity payment levels) government agencies choose. The scrapie indemnity eradication program in the United States (1952–1992) provides a natural laboratory for measuring the responsiveness to government‐set prices. We show that government‐set prices played a major role in determining the program's outcome: the supply of infected animals was price elastic. We argue that short‐run movements in relative prices and the number of infected animals offer a practical method for assessing program effectiveness.
Estimating labor supply of farm households under nonseparability: empirical evidence from Nepal
Authors: Abdulai Awudu , Regmi Punya Prasad
Published: August 2005

This paper examines the labor supply of farm households in Nepal using a recently developed methodology that accounts for the simultaneity between production and consumption decisions of the households. Estimates of marginal products of male and female labor or shadow wages are obtained from an agricultural production function. An instrumental variable approach is then used to recover the household's structural labor supply from variations in the shadow wages and income, as well as other household characteristics. The findings reveal that both male and female total labor supply are sensitive to changes in shadow wages and income. Human capital embodied in education is found to exert a significant positive effect on output, but has no statistically significant impact on total labor supply of individuals. The results also rejects the existence of efficient labor markets in rural Nepal.
Short and long‐run returns to agricultural R&D in South Africa, or will the real rate of return please stand up?
Authors: Schimmelpfennig David , Thirtle Colin , van Zyl Johan , Arnade Carlos , Khatri Yougesh
Published: August 2005

This paper briefly presents the results of a total factor productivity (TFP) study of South African commercial agriculture, for 1947‐1997, and illustrates some potential pitfalls in rate of return to research (ROR) calculations. The lag between R&D and TFP is analyzed and found to be only 9 years, with a pronounced negative skew, reflecting the adaptive focus of the South African system. The two‐stage approach gives a massive ROR of 170%. The predetermined lag parameters are then used in modeling the knowledge stock, to refine the estimates of the ROR from short‐ and long‐run dual profit functions. In the short run, with the capital inputs treated as fixed, the ROR is a more reasonable 44%. In the long run, with adjustment of the capital stocks, it rises to 113%, which would reflect the fact that new technology is embodied in the capital items. However, the long‐run model raises a new problem since capital stock adjustment takes 11 years, 2 years longer than the lag between R&D and TFP. If this is assumed to be the correct lag, the ROR falls to 58%, a best estimate. The paper draws attention to the possible sensitivity of rate of return calculations to assumed lag structure, particularly when the lag between changes in R&D and TFP is skewed.
The allocative efficiency and conservation potential of water laws encouraging investments in on‐farm irrigation technology
Authors: Huffaker Ray , Whittlesey Norman
Published: August 2005

Agricultural water conservation statutes are emerging in the West encouraging private irrigators to improve on‐farm irrigation efficiency as a basinwide conservation measure. We investigate whether private improvements promote the economic efficiency and conservation of water use basinwide under a wide variety of hydroeconomic circumstances. The standard of efficiency is how an irrigation district manager should optimally invest in improving the irrigation efficiencies of individual farms located along a stream while internalizing intrabasin allocative externalities of these investments. The results indicate that the popular Oregon legislative model may be the least effective in conserving water and promoting economically efficient water allocation.
R&D policies for desalination technologies
Authors: Tsur Yacov , Zemel Amos
Published: August 2005

In many arid and semi‐arid regions whether or not to desalinate seawater has long been a non‐issue and policy debates are focused on the timing and extent of the desalination activities. We analyze how water scarcity and demand structure, on the one hand, and cost reduction via R&D programs, on the other hand, affect the desirable development of desalination technologies and the time profiles of fresh and desalinated water supplies. We show that the optimal R&D policy is of a non‐standard most rapid approach path (NSMRAP) type, under which the state of desalination technology — the accumulated learning from R&D efforts — should approach a pre‐specified target process as rapidly as possible and proceed along it thereafter. The NSMRAP property enables a complete characterization of the optimal water policy. The renewable nature of the fresh water stock permits a non‐monotonic behavior of the optimal stock process: under certain conditions, the stock is depleted, to be fully or partly) refilled at a later date.
Linking technical change to research effort: an examination of aggregation and spillovers effects
Authors: Traxler Greg , Byerlee Derek
Published: August 2005

We used a disaggregate approach to examine investment efficiency of wheat breeding research in India. India's total research effort comprizes 20 research programs spread across 50 experiment stations. A technology spillover matrix was constructed for both potential and actual spillovers. Spillovers and free‐riding were dominant characteristics of technical change during the period studied. Although the aggregate rate of return to wheat improvement research in India was estimated to be 55%, eight programs were found to have earned a negative rate of return when spillins were taken into account. Research output is concentrated on a few strong programs. The two strongest programs generated 75% of all the technical change benefits, even though they claimed just 22% of research resources. These two programs include a significant degree of overlap, while on the other hand many farmers were not reached by any of the programs – 56 and 78% of rainfed and durum area, respectively, in 1990 was still sown with pre‐1976 varieties.
Wine market prices and investment under uncertainty: an econometric model for Bordeaux Crus Classés
Authors: Jones Gregory V. , Storchmann Karl‐Heinz
Published: August 2005

This paper describes an econometric assessment of wine market prices for 21 of the Crus Classés châteaux in the Bordeaux region of France. The model developed in the analysis attempts to define the relationship between factors that influence wine quality and those that influence wine prices. Characteristics of the models are: (1) climate influences on grape composition (acid and sugar levels), (2) grape composition influences on market prices, (3) subjective quality evaluations (Parker‐points) on market prices, and (4) the effects of age of the wine on market prices.

The results indicate that composition levels of Merlot‐dominated wines are more climate sensitive than those from Cabernet Sauvignon‐dominated wines. Overall, warm, dry summers result in high sugar and low acid levels at harvest which in turn lead to higher quality wines.

Wine market price sensitivity to Parker‐point ratings indicates that properties with high Cabernet Sauvignon‐dominated wines are highly dependent on the external ratings while Merlot‐dominated wines have a decreased rating sensitivity. Smaller properties tend to gain over proportionally from high ratings indicating great jumps in price from year to year. Additionally, châteaux that have experienced high ratings for past vintages exhibit great sensitivity to point steps in ratings for current vintages.

Aging has a positive effect on Bordeaux wine pricing. This is due to the increasing maturity as well as the increasing absolute scarcity. Absolute scarcity of product is expressed by the size of the property, with small properties producing less per vintage and therefore having less in the market. Additionally, Merlot‐dominated wines exhibit more maturing potential and profit more from aging than Cabernet Sauvignon‐dominated wines.

Average per château real annual profit ranges from 1 to 10%. High levels of grape ripeness, absolute scarcity, and smaller properties that are dominated by Merlot in their blend lead to the highest profits. Forecasts for a vintage not yet on the market indicates that 1995 is better than 1994 for both Cabernet Sauvignon and Merlot‐dominated wines, but that 1996 and 1997 are not as good as 1995, especially for Merlot‐dominated wines.
An ex ante economic and policy analysis of research on genetic resistance to livestock disease: trypanosomosis in Africa
Authors: Falconi Cesar A. , Omamo Steven Were , ďIeteren Guy , Iraqi Fuad
Published: August 2005

This paper undertakes an ex ante economic analysis of research on how resistance to trypanosomosis‐a dominant livestock disease in Africa‐can be maintained and enhanced while retaining and reinforcing characteristics of economic importance to farmers, and on how‘trypanotolerance’ can be imparted to susceptible animals while retaining their other important traits. The results indicate that potential benefits to research‐historically field‐based but increasingly biotechnology‐driven‐range from two to nine times potential costs and that the internal rate of return on investments can be six times the real interest rate. Field‐based research, while exhibiting lower potential benefits on aggregate than does biotechnology research, is also less costly and, because of its more immediate payback, has higher internal rates of return. Returns to biotechnology research hinge on close links with field‐based research and on strategic but relatively small incremental human and capital investments. The results also suggest that further research is needed to consistently identify and track the impacts of alternative intellectual property rights (IPRs) options on the levels and distributions of biotechnology research benefits.
A prospective evaluation of biotechnology in semi‐subsistence agriculture
Authors: Qaim Matin
Published: August 2005

The paper analyses ex ante the economic implications of transgenic virus‐ and weevil‐resistant sweet potatoes in Kenya. These technologies are being developed within international projects, involving public and private organisations. It is expected that the resistant varieties will significantly reduce the crop losses in farmers’ fields. Model calculations show that both innovations are likely to bring about substantial growth in economic surplus. The projected annual gross benefit is 5.4 mUS$ (million US$) for virus resistance and 9.9 mUS$ for weevil resistance. Due to the semi‐subsistence nature of sweet potato, the producing households will be the main beneficiaries. However, market consumers will also capture about one‐fourth of the aggregate welfare gains. The high profitability of the projects is confirmed by significantly positive returns on research investments. The examples demonstrate the viability of successful research partnerships between the public and private sectors. As most of the basic biotechnology tools available to date are patented by private companies in the North, which often do not have sufficient market incentives to develop end‐technologies for the South, more interactions of this kind are required from a development policy perspective. Working with typical semi‐subsistence crops is particularly appealing because it immediately targets the poor and avoids conflicts with the private sector's commercial interests.
Is livestock research unproductive? Separating health maintenance from improvement research
Authors: Townsend Robert , Thirtle Colin
Published: August 2005

Studies of the rates of return to research have usually been based on the implicit assumption that if there were no research, then there would be neither growth nor decline in output or productivity. In the case of livestock, particularly in southern Africa, which has a sub‐tropical disease ecology and a long history of disastrous losses due to disease, the assumption is especially unreasonable. It ignores the losses that would have occurred in the absence of livestock health research, resulting in underestimation of rates of return. This study draws on data from South Africa to illustrate the magnitude of the error, by separating the maintenance effects of animal health research from output increases due to animal improvement research. This is possible because health and improvements research are conducted at separate research institutes and there are data on cattle deaths due to disease, which allows the effects of health expenditures to be calculated. Explicitly, taking the negative effect of diseases into account considerably increases the returns to the livestock research of the South African Agricultural Research Council (SAARC). Instead of a ROR of 18% for animal research in total, the result is a ROR of at least 35% for animal health research and 27% for improvements research, suggesting a minimum underestimation of about 50%. These results suggest that livestock research is productive, once it is properly decomposed. The implication is that all ROR estimates that implicitly assume that with no research, there would be no change in output, or productivity, must be severely biased downwards.
Impact of institutions and public research on private agricultural research⋆
Authors: Alfranca Oscar , Huffman Wallace E.
Published: August 2005

The objective of this paper is to present econometric evidence of the effects of economic incentives and institutions on national aggregate private agricultural R&D investments. An econometric model of national aggregate annual private R&D investment is specified and fitted to panel data consisting of seven EU countries (Austria, Germany, Italy, The Netherlands, Portugal, Spain and Sweden) over “1984”. We find strong impacts of both incentives and institutions on private agricultural R&D investment. Including institutional factors strengthens the story and in some cases greatly changes the results.
Alternative methods for environmentally adjusted productivity analysis
Authors: Hailu Atakelty , Veeman Terrence S.
Published: August 2005

Advances in the productivity with which food is produced around the world have been made possible through the intensive use of industrial inputs that have important environmental impacts. Like standard measures of macroeconomic performance, however, commonly used measures of agricultural efficiency and productivity account only for marketed commodities and inputs, but ignore the environmental effects of these production processes. A more complete analysis of trends in the sector's productivity requires the use of models that incorporate these environmental effects to provide better measures of the contributions of the sector from the social point of view. This paper compares the conceptual merits and empirical performance of alternative approaches that can be employed for this purpose: input distance functions, output distance functions, nonparametric methods, and index number approaches. Each of the methods has relative strengths and weaknesses. The methods are empirically illustrated using data from the Canadian pulp and paper industry.
An economic evaluation of the environmental benefits from pesticide reduction
Authors: Brethour Cher , Weersink Alfons
Published: August 2005

Previous studies on the environmental impacts of pesticide use have tended to focus either on measuring damages through changes in relative risks to various environmental categories or examining the trade‐off between pesticide use levels and abatement costs. This study uses the physical risk assessment approach combined with contingent valuation survey results on consumers’ willingness to reduce pesticide risk. The reduction in external costs associated with the changes in pesticide use in Ontario agriculture between 1983 and 1998 is U© 188 per household. The environmental benefits are largely due to the reduction in the level of high and moderate‐risk pesticides.
What explains price volatility changes in commodity markets? Answers from the world palm‐oil market⋆
Authors: Voituriez Tancrède
Published: August 2005

What are the sources of commodity price volatility changes? Based on observation of the palm‐oil market (1818–1999). our hypothesis is that the superimposition of short‐distance operators located near the export supply, whose expectation horizon is limited to a few weeks, and long‐distance operators further from the export supply, whose expectation horizon exceeds six months to one year, is responsible for volatility changes and market instability. Because of the superimposition of expectations horizons, volatility grows along with the development of short‐distance trade. We support this hypothesis using a trader‐behavior model derived from Day and Huang [J. Econ. Behavior Org. 14 (1990) 299] and Day [Complex Economic Dynamics, Vol. I. MIT Press, Cambridge, MA]. Our simulation results challenge the argument that trade liberalization and market enlargement necessarily reduce commodity prices volatility.
Towards greater food security for India's poor: balancing government intervention and private competition
Authors: Umali‐Deininger Dina L. , Deininger Klaus W.
Published: August 2005

To achieve its strategic objective of food security, the Government of India (GOI) maintains an elaborate set of food grain policies which include public procurement and price support operations, price stabilisation through buffer stocks, public food grain distribution, and extensive controls on private trade. We use aggregate and household level evidence to show that this system is costly, generates inefficiencies in the food grain marketing system (for both the public and the private sector), and often offers few, if any, benefits to its intended beneficiaries, the poor. On this basis we propose an integrated reform agenda involving improvements in the targeting of the public distribution system, creation of an enabling environment for increased private participation in food grain markets and greater incentives for efficiency by the Food Corporation of India (FCI).
The impact of food scares on price adjustment in the UK beef market
Authors: Lloyd Tim , McCorriston S. , Morgan C.W. , Rayner A.J.
Published: August 2005

This paper considers the impact of‘food scares, predominately concerns relating to BSE, on UK beef prices at retail, wholesale and producer levels over the 1990s. Acknowledging the co‐movement that exists between prices in the meat marketing chain, we use a co‐integrating framework, the results of which show the importance of publicity regarding the safety of food in the transmission of beef prices in the UK. The‘food publicity’ index that we use has a marked negative impact on the prices at all levels, a result that is consistent with the effect of an inward shift in the demand function. Moreover, the extent of price decline varies between the marketing stages entailing that the price spreads rise in response to an increase in the (negative) publicity about food safety. While not a formal test of market power, these observations are consistent with recent theoretical results demonstrating that market power exacerbates price changes in the upstream sectors for a given change in the retail demand function. The implication of these varying price changes is that the food safety concerns also cause the marketing margins between the stages to widen. The UK's Competition Commission has recently investigated the abuse of market power in the food sector, inspired largely by this specific issue.
Measuring soil quality dynamics A role for economists, and implications for economic analysis
Authors: Kim Kwansoo , Barham Bradford L. , Coxhead Ian
Published: August 2005

Measuring soil quality is extremely difficult, yet it has clear economic importance. In particular, there is a great deal of empirical interest in the dynamics of soil quality evolution when land managers respond to policies and other incentives. Yet current methodologies for measuring changes in agricultural land quality are largely static and rely heavily either on incomplete measures such as proxy variables, or ad hoc indexes of selected soil characteristics. Moreover, much empirical work relies on static econometric techniques or simulation models. In this paper, we develop a means to infer soil quality changes from input and output data using a dynamic production function model. Using data from field experiments, we estimate the model in a way that allows the recovery of a dynamic measure of soil quality whose evolution depends on variations in management practices. Our methodology and findings will help provide firmer empirical foundations for analyses of the economic implications of land degradation and the soil quality implications of agricultural policies.
How does gender affect the adoption of agricultural innovations?
Authors: Doss Cheryl R. , Morris Michael L.
Published: August 2005

Why do men and women adopt agricultural technologies at different rates? Evidence from Ghana suggests that gender‐linked differences in the adoption of modern maize varieties and chemical fertilizer result from gender‐linked differences in access to complementary inputs. This finding has important policy implications, because it suggests that ensuring more widespread and equitable adoption of improved technologies may not require changes in the research system, but rather introduction of measures that ensure better access for women to complementary inputs, especially land, labor, and extension services.
The effect of barge and ocean freight price volatility in international grain markets
Authors: Haigh Michael S. , Bryant Henry L.
Published: August 2005

This paper looks at the potential role of time‐varying volatility of Mississippi river barge and ocean freight prices on commodity prices in Illinois, at the US Gulf and in Rotterdam using a Vector Error Correction GARCH‐in‐Mean model. The model is used to infer the extent to which transportation price risk affects price dynamics in international grain markets. Results from a simulation exercise indicate that both barge and ocean price volatility influence grain prices, but barge price volatility tends to have a greater impact on grain prices and marketing margins than that arising from ocean price volatility. Consistent with most studies that evaluate the role of risk in marketing channels, results here suggest that a reduction in barge rate risk would reduce marketing margins between Illinois and the US Gulf, and between the US Gulf and Rotterdam. The existence of an ocean freight futures contract coupled with the lack of a futures contract for barge rates may be partially responsible for the finding that barge rates have a significant influence on grain prices and contribute most to wide marketing margins found throughout the international grain‐marketing system.
Income distribution in rice–growing villages during the post‐Green Revolution periods: the Philippine case, 1985 and 1998
Authors: Estudillo Jonna P. , Quisumbing Agnes R. , Otsuka Keijiro
Published: August 2005

This paper aims to examine changes in household income sources and its impact on household income distribution in the post‐Green Revolution periods in 1985 and 1998 in the rural Philippines. We found that there has been a structural shift of household income away from farm in favor of nonfarm labor income sources. This finding indicates that rural development is being led by nonfarm sectors. Such a shift has resulted in an increase in household income inequality as the distribution of nonfarm income has become less equal over time and was markedly more unequal than that of farm income in 1998.
The potential impact of climate change on Taiwan's agriculture
Authors: Chang Ching‐Cheng
Published: August 2005

This paper intends to estimate the potential impact of climate change on Taiwan's agricultural sector. Yield response regression models are used to investigate the climate change's impact on 60 crops. A price‐endogenous mathematical programming model is then used to simulate the welfare impacts of yield changes under various climate change scenarios. Results suggest that both warming and climate variations have a significant but non‐monotonic impact on crop yields. Society as a whole would not suffer from warming, but a precipitation increase may be devastating to farmers.