bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between plasma concentrations of N‐terminal pro brain natriuretic peptide and the characteristics and outcome of patients with a clinical diagnosis of diastolic heart failure: a report from the PEP‐CHF study
Authors: Cleland John G.F. , Taylor Jacqueline , Freemantle Nick , Goode Kevin M. , Rigby Alan S. , Tendera Michal
Published: April 2012

Aim

The aim of this study was to explore the relationships between plasma concentrations of N‐terminal pro brain natriuretic peptide (NT‐proBNP) and characteristics and prognosis of patients with heart failure and preserved (HFPEF) left ventricular ejection fraction (LVEF). No substantial trial has shown that treatment alters prognosis in patients with HFPEF due, in part, to much lower than anticipated event rates. The lack of a simple, objective test to identify patients with HFPEF at increased risk of cardiovascular events would be valuable.

Methods and results

The Perindopril in Elderly People with Chronic Heart Failure Trial (PEP‐CHF) was a randomized, controlled trial comparing perindopril and placebo in patients with symptoms and signs of heart failure who had an LVEF >40% and evidence of LV diastolic dysfunction. The primary endpoint was all‐cause mortality or heart failure‐related hospitalization. NT‐proBNP was measured in 375 patients. Quartile thresholds were 176, 409, and 1035 pg/mL. Patients in the highest quartile of NT‐proBNP were older, had lower body mass, more often had atrial fibrillation, had greater atrial and ventricular dimensions and a lower LVEF, and were more likely to receive loop diuretic therapy. Compared with the first quartile of NT‐proBNP, the hazard ratios for the primary endpoint in the second {1.38 [95% confidence interval (CI) 0.64–2.99]}, third [2.84 (95% CI 1.42–5.72)], and fourth [4.47 (95% CI 2.30–8.72)] quartiles were increased. In a multivariable model, NT‐proBNP, but not echocardiographic measures, was associated with outcome.

Conclusions

NT‐proBNP is a powerful prognostic marker in patients with HFPEF.
Revised-Path Dependence
Authors: Bednar Jenna , Page Scott E. , Toole Jameson L.
Published: April 2012

In this article, we define a class of revised path—dependent processes and characterize their basic properties. A process exhibits revised-path dependence if the current outcome can revise the value of a past outcome. A revision could be a change to that outcome or a reinterpretation. We first define a revised path—dependent process called the accumulation process: in each period, a randomly chosen past outcome is changed to match the current outcome and show that it converges to identical outcomes. We then construct a general class of models that includes the Bernoulli process, the Polya process, and the accumulation process as special cases. For this general class, we show that, apart from knife-edge cases, all processes converge either to homogeneous equilibria or to an equal probability distribution over types. We also show that if random draws advantage one outcome over the other, then the process has a unique equilibrium.
The Collapse of the Soviet Union and the Productivity of American Mathematicians*
Authors: Borjas George J. , Doran Kirk B.
Published: April 2012

It has been difficult to open up the black box of knowledge production. We use unique international data on the publications, citations, and affiliations of mathematicians to examine the impact of a large, post-1992 influx of Soviet mathematicians on the productivity of their U.S. counterparts. We find a negative productivity effect on those mathematicians whose research overlapped with that of the Soviets. We also document an increased mobility rate (to lower quality institutions and out of active publishing) and a reduced likelihood of producing “home run” papers. Although the total product of the preexisting American mathematicians shrank, the Soviet contribution to American mathematics filled in the gap. However, there is no evidence that the Soviets greatly increased the size of the “mathematics pie.” Finally, we find that there are significant international differences in the productivity effects of the collapse of the Soviet Union, and these international differences can be explained by both differences in the size of the émigré flow into the various countries and in how connected each country is to the global market for mathematical publications.
Tomato infectious chlorosis virus Associated with Tomato Diseases in Baja California, Mexico
Authors: Méndez-Lozano J. , Magallanes-Tapia M. A. , Romero-Romero J. L. , Camacho-Beltrán E. , Vega W. L. Orduño , Leyva-López N. E. , Santos-Cervantes M. E. , Félix-Gastélum R.
Published: April 2012

Tomato (Solanum lycopersicum L.) is an important vegetable crop in Mexico. The national production in 2009 was 2,043,814 metric tons with a value of $163,560,636 US. Since 2007, abnormal yellow and crispy leaves were observed in commercial tomato fields in Ensenada County, Baja California, Mexico. In affected fields from two localities (San Quintín Valley and Ensenada), symptomatic plants were randomly distributed and symptoms resembled previous descriptions of crinivirus infections in tomato (3). The symptoms and the presence of whiteflies (Bemisia tabaci and Trialeurodes vaporariorum) in the affected fields suggested a viral etiology. Leaf samples of 143 symptomatic tomato plants were collected in the 2007 and 2008 growing seasons. Total RNA was extracted and analyzed by reverse transcription (RT)-PCR assay for simultaneous detection of Tomato infectious chlorosis virus (TICV) and Tomato chlorosis virus (ToCV). Degenerate primers (HS-11/HS-12) were used in combination with specific primers (TIC-3/TIC-4 and ToC-5/ToC-6) for detection of these viruses by nested-PCR (2). A PCR fragment of the expected size for TICV (223 bp) was amplified in 26 of 143 samples. None of the samples tested positive for ToCV. In addition, considering that whiteflies are vectors of begomoviruses, samples were also tested for presence of viral DNA. Results showed 30 positive samples and one with mixed infection. It is therefore possible that the viral disease symptoms observed could be caused in part by viruses other than TICV. Three amplicons from RT-PCR of tomato samples were cloned into the pGEM-T easy vector system II (Promega Corporation, Madison, WI) and sequenced. The sequence of one amplicon (GenBank Accession No. FJ609651) was compared with the sequences of other criniviruses reported in the NCBI/GenBank database using the Clustal V alignment method of the sequence analysis software suite Lasergene (MegAling, DNASTAR Inc., Madison, WI). Sequence analysis of the 223-bp PCR fragment corresponding to TICV showed 99.1% identity with a TICV isolate from Japan (GenBank Accession No. AB085602) and 100% identity with TICV isolates from the United States (GenBank Accession No. TIU67449). Although the presence of another crinivirus, ToCV, was reported previously in Mexico associated with tomato crops and two native weeds, S. nigrescens and Datura stramonium (1), this virus was not detected in Baja California during the present work. To our knowledge, this is the first report of TICV associated with tomato diseases in Mexico. The emerging of a previously unreported virus disease in tomato production areas of Mexico complicates disease management efforts.

References: (1) P. Álvarez-Ruíz et al. Plant Pathol. 56:1043, 2007. (2) C. I. Dovas et al. Plant Dis. 86:1345, 2002. (3) G. C. Wisler et al. Plant Dis. 82:270, 1998.
Effect of Sclerotial Water Content on Carpogenic Germination of Sclerotinia sclerotiorum
Authors: Nepal Achala , del Río Mendoza Luis E.
Published: April 2012

The relationship between moisture content and carpogenic germination (CG) of Sclerotinia sclerotiorum sclerotia and the dynamics of sclerotial water imbibition were studied in a controlled environment. The study was conducted using laboratory-produced sclerotia from seven S. sclerotiorum isolates. The quantity and rate of water imbibition by three sizes of sclerotia was determined gravimetrically in silty clay, sandy loam, and sandy soils maintained at 100, 75, 50, and 25% of soil saturation and in distilled water. Smaller sclerotia imbibed water at a significantly faster rate (P = 0.05) than larger sclerotia in water and in soil at all saturation percentages. When buried in soil, small, medium, and large sclerotia were fully saturated within 5, 15, and 25 h, respectively, in all three soil types and moisture percentages. The effect of sclerotia moisture content on CG was evaluated on sclerotia maintained at 95 to 100, 70 to 80, 40 to 50, and 20 to 30% of their water saturation capacity using cool mist humidifiers. Sclerotial moisture content significantly influenced CG (P = 0.05). Maximum CG was observed on fully saturated sclerotia, while no CG was observed below 70 to 80% of saturation. These findings help explain S. sclerotiorum's ability to produce apothecia in soils with relatively low moisture levels.
A new approach to gas sensing with nanotechnology
Authors: Sharma Swati , Madou Marc
Published: April 2012

Nanosized gas sensor elements are potentially faster, require lower power, come with a lower limit of detection, operate at lower temperatures, obviate the need for expensive catalysts, are more heat shock resistant and might even come at a lower cost than their macro-counterparts. In the last two decades, there have been important developments in two key areas that might make this promise a reality. First is the development of a variety of very good performing nanostructured metal oxide semiconductors (MOSs), the most commonly used materials for gas sensing; and second are advances in very low power loss miniaturized heater elements. Advanced nano- or micro–nanogas sensors have attracted much attention owing to a variety of possible applications. In this article, we first discuss the mechanism underlying MOS-based gas sensor devices, then we describe the advances that have been made towards MOS nanostructured materials and the progress towards low-power nano- and microheaters. Finally, we attempt to design an ideal nanogas sensor by combining the best nanomaterial strategy with the best heater implementation. In this regard, we end with a discussion of a suspended carbon nanowire-based gas sensor design and the advantages it might offer compared with other more conventional gas sensor devices.
Phylogenetic analyses of pandemic influenza A (H1N1) virus in university students at Tobetsu, Hokkaido, Japan
Authors: Inoue Emi , Ieko Masahiro , Takahashi Nobuhiko , Osawa Yoshiaki , Okazaki Katsunori
Published: April 2012

Pandemic influenza H1N1 virus (A[H1N1]pdm09) emerged in 2009. To determine the phylogeography of A(H1N1)pdm09 in a single population, 70 strains of the virus were isolated from university students or trainee doctors at Tobetsu, Hokkaido, Japan, between September and December 2009. The nucleotide sequences of the HA1 region of the HA genes and described phylogenetic relationships of the strains circulating among them were analyzed. It was found that the 70 isolates could be phylogenetically separated into three groups and that two epidemics were caused by different groups of the virus. The three groups were also distinguishable from each other by three amino acid changes: A197T, S203T and Q293H. The substitution of S203T, which is located in the antigenic site, suggests antigenic drift of the virus.
Clinical predictors of apnoea‐hypopnoea during propofol sedation in patients undergoing spinal anaesthesia*
Authors: Kim G. H. , Lee J. J. , Choi S. J. , Shin B. S. , Lee A. R. , Lee S. H. , Kim M. H.
Published: April 2012

This study assessed the relationship between the occurrence of apnoea‐hypopnoea during propofol sedation for spinal anaesthesia and two different predictive tests of sleep apnoea: the STOP‐Bang score (snoring while sleeping, daytime tiredness, observed breathing stoppages, high blood pressure–body mass index, age, neck circumference, gender); and the obstructive sleep apnoea (OSA) score. Thirty‐four middle‐aged men not diagnosed with obstructive sleep apnoea received propofol infusions adjusted to produce a bispectral index of 70–75. ApnoeaLinkTM was used to estimate the incidence of apnoea‐hypopnoea. The median (IQR [range]) apnoea‐hypopnoea index was 17 (8–24 [0–70]) events.h−1 and correlated weakly with the STOP‐Bang score (p = 0.022, r = 0.423) and moderately with the OSA score (p < 0.001, r = 0.693). Severe apnoea‐hypopnoea developed more frequently in patients with a higher OSA score (34.5% vs 0%) or higher STOP‐Bang score (27.6% vs 6.9%). Both assessment tools have some predictive value for the occurrence of apnoea‐hypopnoea during propofol sedation in patients undergoing spinal anaesthesia.
Development of a behavioural marker system for scrub practitioners' non‐technical skills (SPLINTS system)
Authors: Mitchell Lucy , Flin Rhona , Yule Steven , Mitchell Janet , Coutts Kathy , Youngson George
Published: April 2012

Rationale, aims and objectives  Adverse events still occur despite ongoing efforts to reduce harm to patients. Contributory factors to adverse events are often due to limitations in clinicians’ non‐technical skills (e.g. communication, situation awareness), rather than deficiencies in technical competence. We developed a behavioural rating system to provide a structured means for teaching and assessing scrub practitioners’ (i.e. nurse, technician, operating department practitioner) non‐technical skills.

Method  Psychologists facilitated focus groups (n = 4) with experienced scrub practitioners (n = 16; 4 in each group) to develop a preliminary taxonomy. Focus groups reviewed lists of non‐technical‐skill‐related behaviours that were extracted from an interview study. The focus groups labelled skill categories and elements and also provided examples of good and poor behaviours for those skills. An expert panel (n = 2 psychologists; n = 1 expert nurse) then used an iterative process to individually and collaboratively review and refine those data to produce a prototype skills taxonomy.

Results  A preliminary taxonomy containing eight non‐technical skill categories with 28 underlying elements was produced. The expert panel reduced this to three categories (situation awareness, communication and teamwork, task management), each with three underlying elements. The system was called the Scrub Practitioners’ List of Intraoperative Non‐Technical Skills system. A scoring system and a user handbook were also developed.

Conclusion  A prototype behavioural rating system for scrub practitioners’ non‐technical skills was developed, to aid in teaching and providing formative assessment. This important aspect of performance is not currently explicitly addressed in any educational route to qualify as a scrub practitioner.
The role of OsCOM1 in homologous chromosome synapsis and recombination in rice meiosis
Authors: Ji Jianhui , Tang Ding , Wang Kejian , Wang Mo , Che Lixiao , Li Ming , Cheng Zhukuan
Published: April 2012

COM1/SAE2 is a highly conserved gene from yeast to higher eukaryotes. Its orthologs, known to cooperate with the MRX complex (Mre11/Rad50/Xrs2), are required for meiotic DNA double‐strand break (DSB) ends resection and specific mitotic DSB repair events. Here, the rice (Oryza sativa, 2n = 2x = 24) COM1/SAE2 homolog was identified through positional cloning, termed OsCOM1. Four independent mutants of OsCOM1 were isolated and characterized. In Oscom1 mutants, synaptonemal complex (SC) formation, homologous pairing and recombination were severely inhibited, whereas aberrant non‐homologous chromosome entanglements occurred constantly. Several key meiotic proteins, including ZEP1 and OsMER3, were not loaded normally onto chromosomes in Oscom1 mutants, whereas the localization of OsREC8, PAIR2 and PAIR3 seemed to be normal. Moreover, OsCOM1 was loaded normally onto meiotic chromosomes in Osrec8, zep1 and Osmer3 mutants, but could not be properly loaded in Osam1, pair2 and OsSPO11‐1RNAi plants. These results provide direct evidence for the functions of OsCOM1 in promoting homologous synapsis and recombination in rice meiosis.
An approach to the determination of winter chill requirements for different Ribes cultivars
Authors: Jones H. G. , Hillis R. M. , Gordon S. L. , Brennan R. M.
Published: April 2012

Winter chilling is critical for flowering and fruiting of many temperate fruits, with evidence that blackcurrant (Ribes nigrum L.) cropping has been adversely affected by warm winters. Accurate models of chill accumulation in blackcurrant are required so that breeding strategies can be formulated for the generation of new cultivars with resilience to future climates. Existing models for chill accumulation have largely been derived from statistical correlation; here we report the derivation of improved models for blackcurrant using controlled environment treatments. Hardwood cuttings from a diverse set of cultivars were exposed to constant or varying chilling temperatures and the effects on bud break after transfer to a warm, permissive environment evaluated. The impact of different combinations of temperature and chilling periods were described in terms of their overall ‘Effectiveness’ (E). Clear genotypic differences were found, with excessive chilling often inhibiting bud break. There was a significant interaction between observed chilling response and the period of low temperature exposure. A number of chilling models to explain observed interactions between chilling temperature and time of exposure on bud break were compared; the most effective involved an optimal response to increasing chill accumulation. The effects of varying temperatures during chilling on bud break were complex, with warm temperature breaks substantially inhibiting bud development and cooler temperature breaks tending to enhance bud burst. The relevance of these models to generic studies of endodormancy is discussed, together with their potential application to the development of phenotyping screens for future breeding using diverse blackcurrant germplasm.
Analysing quantitative parent‐of‐origin effects with examples from ultrasonic measures of body composition In Australian beef cattle
Authors: Tier B. , Meyer K.
Published: April 2012

Parent‐of‐origin effects arise when an individual’s genes are modified during gametogenesis. Commonly known as imprinting, affected genes may be completely, or partially, suppressed. Individual loci in mice, human and sheep are known to be imprinted, and the quantitative effects of imprinted loci have been found for many carcass traits in cattle and pigs. Differentiating between five types of loci – direct additive loci and partially and completely imprinted loci by sires and dams – is not possible as their effects are confounded such that only three of seven parameters can be estimated. An analysis of Australian Hereford and Angus heifers and bulls for four ultrasonic measures of body composition – eye muscle area, rib fat, rump fat and intramuscular fat per cent – found parent‐of‐origin effects for both parents in most trait‐gender data sets and that they were an average of 28% of the total genetic variance. No parent‐of‐origin effects were found for Hereford bull intramuscular fat per cent and the maternal parent‐of‐origin effects were not significant for Angus Heifer eye muscle area.
Calculation of identity‐by‐descent probabilities of short chromosome segments
Authors: Tuchscherer A. , Teuscher F. , Reinsch N.
Published: April 2012

For some purposes, identity‐by‐descent (IBD) probabilities for entire chromosome segments are required. Making use of pedigree information, length of the segment and the assumption of no crossing‐over, a generalization of a previously published graph theory oriented algorithm accounting for nonzero IBD of common ancestors is given, which can be viewed as method of path coefficients for entire chromosome segments. Furthermore, rules for setting up a gametic version of a segmental IBD matrix are presented. Results from the generalized graph theory oriented method, the gametic segmental IBD matrix and the segmental IBD matrix for individuals are identical.
Feeding and oviposition preference of Frankliniella occidentalis for crops and weeds in Kenyan French bean fields
Authors: Nyasani J. O. , Meyhöfer R. , Subramanian S. , Poehling H.‐M.
Published: April 2012

Western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is an important pest of French beans in Kenya. However, information on the feeding activity and oviposition preference of WFT on crop and weed hosts associated with French beans in Kenya and other parts of the world is lacking. To determine the feeding and oviposition preference of WFT for crop and weed plants commonly encountered in French bean fields in Kenya, no‐choice and choice experiments were conducted using four important crop and weed plants. Among the crop plants tested, highest feeding and oviposition activity of WFT was recorded on courgette/zucchini (Cucurbita pepo L.) and French beans (Phaseolus vulgaris L.). Spinach beet (Beta vulgaris L.) and sweet pepper (Capsicum annuum L.) were of relatively minor importance for feeding and oviposition. Among the weeds tested, gallant soldier (Galinsoga parviflora Cav.) was the most preferred host plant for feeding and oviposition compared with Chinese lantern (Nicandra physaloides L.), wild crucifer (Erucastrum arabicum Fisch. & C.A. Mey.) and pigweed (Amaranthus hybridus L.). Phaseolus vulgaris was the most preferred host for feeding and oviposition in the presence of G. parviflora, E. arabicum and A. hybridus. A positive correlation between the number of feeding punctures and the number of eggs oviposited by WFT on crop and weed plants was observed. The results of this study show that P. vulgaris, C. pepo and G. parviflora are both relatively good feeding and oviposition hosts of WFT. Cucurbita pepo and G. parviflora may serve as potential sources of WFT outbreaks within French bean fields.
Curtobacterium flaccumfaciens pv. flaccumfaciens on Soybean in Germany – A Threat for Farming
Authors: Sammer Ulrike F. , Reiher Katharina
Published: April 2012

Plant diseases caused by Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) are distributed in North and South America as well as in South and East Europe and occur mostly on beans (Phaseolus vulgaris). This is the first report of Cff on soybean in Germany. Cff was detected in complex with Pseudomonas syringae pv. glycinea on field‐grown soybeans that were not treated with pesticides. Cff, the causal agent of bacterial tan spot disease, was identified by 16S rDNA sequencing and by artificial infection and re‐isolation from the host plants soybean (Glycine max) and bush bean (Phaseolus vulgaris).
Randomized controlled trial of probiotics to reduce common cold in schoolchildren
Authors: Rerksuppaphol Sanguansak , Rerksuppaphol Lakkana
Published: April 2012

Background:  The common cold is responsible for the largest proportion of school and work absenteeism and causes a huge economic burden. None of the current interventions is greatly effective for prevention. Our aim was to assess the efficacy of a two‐strain combination probiotic for prevention of common cold symptoms in healthy schoolchildren.

Methods:  A double‐blind randomized controlled trial was performed during the winter season in a public school of central Thailand. Children, aged 8–13 years, were randomized to receive either a two‐strain combination probiotic (Lactobacillus acidophilus and Bifidobacterium bifidum) or placebo given twice a day for 3 months. The primary outcome was any symptom of cold during the 3‐month study period while vomiting, diarrhea, use of antibiotics, school absence due to any cause, school absence due to cold and duration of all symptoms were secondary outcomes.

Results:  Of the 40 children in each group, 31 (77%) in the probiotic group, compared to 38 (95%) in the placebo group (P= 0.048), developed at least one symptom of cold. Children in the probiotics group had significantly lower risk of fever, cough, rhinorrhea, school absence and school absence related to common cold compared to children in the placebo group. There was no impact on diarrhea and vomiting.

Conclusion:  A two‐strain probiotic combination given twice a day for 3 months was able to reduce the symptoms of the common cold and school absenteeism in schoolchildren.
The Hanseatic League and the Concept of Functional Overlapping Competing Jurisdictions
Authors: Fink Alexander
Published: April 2012

I explore the medieval phenomenon of theHanseaticLeague. I use the concept offunctional overlapping competing jurisdictions(FOCJ) discussed byFrey andEichenberger (1996,1999,2000) as framework for my analysis of the medieval association of northernEuropean traders and cities. I show that theHanseaticLeague came close to representing an example of aFOCJ. But I find that in contrast to theFOCJoutlined byFrey andEichenberger the polycentricHanseaticLeague as an inter‐regional structure lacked the characteristic of a jurisdiction. It was not a political authority with the power to tax and regulate its members. The arrangements between the members of theHanseaticLeague therefore had to be self‐enforcing. Building on my investigation of theHanseaticLeague, I further provide a general discussion of the costs and benefits of a central political authority in a system of functional overlapping competing units.
Seasteading: Competitive Governments on the Ocean
Authors: Friedman Patri , Taylor Brad
Published: April 2012

We argue that those advocating the reform of current political systems in order to promote jurisdictional competition are in a catch‐22: jurisdictional competition has the potential to improve policy, but reforms to increase competition must be enacted by currently uncompetitive governments. If such governments could be relied upon to enact such reforms, they would likely not be necessary. Since existing governments are resistant to change, we argue that the only way to overcome the deep problem of reform is by focusing on the bare‐metal layer of society – the technological environment in which governments are embedded. Developing the technology to create settlements in international waters, which we refer to as seasteading, changes the technological environment rather than attempting to push against the incentives of existing political systems. As such, it sidesteps the problem of reform and is more likely than more conventional approaches to significantly alter the policy equilibrium.
Who Are the Giants on Whose Shoulders We Stand?
Authors: Laband David N. , Majumdar Suman
Published: April 2012

The scientific community is just that – a community – and the success/influence of any one individual likely reflects, at least in certain measure, the contributions made previously by others. This suggests that rather than merely ranking economists on the basis of raw citation counts, one might gain real insights about the giants laboring in relative obscurity by identifying who the authors of exceptionally influential papers drew their inspiration from. We identify the most‐highly‐cited (409) papers published in economics from 2001–2005, then examine who the authors of these high‐impact papers drew from in terms of developing the ideas/arguments/applications presented in these papers. We find that a very small group of individuals had a comparatively large impact on the economics profession, in terms of influencing the subsequent work of authors of extraordinarily highly‐cited papers. Further, there is relatively little consistency between our list of ‘giants’ and Nobel Prize winners in Economics.
RESOURCE PRODUCTIVITIES IN AN IRRIGATED DAIRYING AREA*
Authors: Hickey G.J. , Lloyd Alan G.
Published: April 2012

In 1962‐63 a survey was conducted of forty‐three dairy farmers in the Nambrok‐Denison area of the Central Gippsland Irrigation District, near Maffra, in Victoria. One of the main purposes of the survey was to obtain estimates of resource productivities, using the Cobb‐Douglas production function approach.

This approach, to be successful, requires (inter alia) a high degree of uniformity between farms as regards soil, climate, stage of development and technical efficiency in management. A detailed soil survey of the area was available, and all eligible farms on a group of closely similar soil types were included in the sample. The restricted area ensured uniformity of climate (23" rainfall) and the fact that the farms were part of a Soldier Settlement Commission development, commenced in 1951, suggested that there would be less variance in stage of development and technical efficiency than is encountered in most farm surveys (assuming the Commission's selection procedures have some efficacy).
COHORT ANALYSIS OF THE DAIRY FARM WORK FORCE
Authors: Bird J.G.
Published: April 2012

This paper traces variations in the dairy farm work force in Victoria, New South Wales, and Queensland. Although the substantial differences between States in income levels are reflected in differing rates of reduction in the work force, these differences are not also reflected by appreciable differences in mean age and age structure. The cohort analysis explains this observation.
THE ESTIMATION OF PRODUCTION FRONTIERS: THE AUSTRALIAN LIVESTOCK/CEREALS COMPLEX1
Authors: Powell Alan A. , Gruen Fred H.G.
Published: April 2012

An attempt is made to combine, empirically, the estimation of product transformation surfaces with the more conventional methods of linear supply analysis. This synthetic approach is used to fit simultaneously a system of six aggregate supply functions. The products covered account for more than 70 per cent of the gross value of Australian rural production.
DROUGHT AND THE MULTIPLIER1
Authors: Duloy J.H. , Woodland A.D.
Published: April 2012

The effects of a 20 per cent across‐the‐board drought‐year reduction in farm output upon G.N.P., imports and the balance of payments are estimated via an econometric mode of the Australian economy. The effects do not appear to be overly large and taper off rapidly in succeeding years.
STATIONARY‐STATE SOLUTIONS IN MULTI‐PERIOD LINEAR PROGRAMMING PROBLEMS
Authors: Throsby C.D.
Published: April 2012

Multi‐period linear programming models are classified initially. The main interest of this paper is in models of cyclical activity. The conditions under which such models lead to stable repetitive optimal solutions are defined. A simple technique is presented by which this stable solution (termed here the "stable core") can be derived without recourse to solving a full extended matrix. Firm‐level applications of this model in agriculture are discussed.
OPTIMIZING THE TRANSFER OF TAX EXEMPTIONS IN NEW ZEALAND FARM DEVELOPMENT*
Authors: Cartwright Wayne
Published: April 2012

Farmers and their advisers frequently face complex problems involving the scheduling of claims for tax exemptions. A case in point is the New Zealand tax law allowing farmers to transfer exemptions associated with development expenditure up to specified time horizons. This paper examines procedures for solving this, and similar, problems. Linear programming could be used, but an alternative algorithm is proposed for farm advisers whose access to computing facilities is limited. The latter procedure is intended for use with forecast budgeting in farm development planning.
TRENDS IN FOOD MARKETING IN THE UNITED STATES
Authors: Gruen Fred H.G.
Published: April 2012

This article discusses some major trends in food marketing in the United States, as revealed in a detailed study of food distribution undertaken by the National Commission on Food Marketing. Attention is focused on the growing industrialisation of farming and the consequent decline in terminal auction markets; the increasing role of new product development in ensuring profitability of food processors. Trends in the food retailing industry are also discussed and compared with conditions prevailing in Australia.
FARM CREDIT POLICY IN THE EARLY STAGES OF AGRICULTURAL DEVELOPMENT*
Authors: Penny D.H.
Published: April 2012

This paper discusses the farm credit policies pursued by governments in low‐income countries. It is argued that, in the early stages of development, peasant attitudes to debt are such that cheap credit is unlikely to be a useful growth stimulus. It is shown that the effectiveness of credit depends on the ability and willingness of the peasants to devote such additional funds to productive uses. The poor performance of many government rural credit programmes in low‐income countries is discussed and criteria for a successful programme are presented.
BOOK REVIEWS
Authors: MORELLI EMERY A.
Published: April 2012

Fundamentals of Modern Agriculture. Edited by C. D. Blake.

Distribution of Groceries. Economic Aspects of the Distribution of Groceries, with Special Reference to Western Australia. By D. H. Briggs and R. L. Smyth.

Marketing and Economic Development. Edited by C. J. Miller.

Agricultural Producers and Their Markets. Edited by T. K. Warley.

Agricultural Development in Tropical Africa. By J. D. DE Wilde et. al.

Wool? Modern Myths and New Horizons, By G. S. LE Couteur.

Agricultural Economics in Tangunyiku. By H. Ruthenberg.

Back of Bourke. By R. L. Heathcote.

Shearing Shed Management. By H. S. Woodbridge.

Tax Burden on Indian Agriculture. By V. P. Gandhi.

A General Theory of Tax Structure Change During Economic Development. By H. H. Hinricks.

The Economics of Agricultural Development. By J. W. Mellor.
A SIMULATED STUDY OF AN AUCTION MARKET
Authors: Whan R.B. , Richardson Robert A.
Published: April 2012

A simulated model of an auction market is developed showing the relationship between the variation in valuations, the price variation and the number of independent bidders in the market. Average prices paid in a market with two or three bidders are less than average valuations. Average prices are progressively greater than average valuations as the number of bidders increases beyond four. Some applications of this model in the Australian wool market are discussed.
A STUDY OF BANANA SUPPLY AND PRICE PATTERNS ON THE SYDNEY WHOLESALE MARKET: AN APPLICATION OF SPECTRAL ANALYSIS*
Authors: Aggrey‐Mensah W. , Tuckwell N.E.
Published: April 2012

Spectral analysis is applied to weekly supply and price series for bananas traded on the Sydney wholesale market. Many interesting features are revealed such as the pronounced seasonal component and the two week lag structure between the supply and price series. These results are discussed in relation to the known behaviour of the market and some implications for marketing decisions are tentatively drawn.
FUTURE AUSTRALIA‐JAPAN TRADE RELATIONS
Authors: Bieda K.
Published: April 2012

The leitmotif of this paper is the strong, rising and alarming trend of deficits in Australia's balance of payments current account, which makes it overwhelmingly important to increase exports. Market promotion, substantially the existing method, will not do the job in a world with politically set up trade barriers. Multilateral political negotiations about the removal of the trade barriers within the G.A.T.T. system are unlikely to help for Australia's range of exports. Therefore Australia must enter into bilateral negotiations with any likely important customer, the most obvious one being Japan, to lower trade barriers on a bilateral basis, and this under the existing international agreements can be done only under the guise of a partial free trade area.
THE ELASTICITY OF DEMAND FOR THE EXPORTS OF A SINGLE COUNTRY — A RECONSIDERATION
Authors: Taplin J.H.E.
Published: April 2012

One country's exports of a particular commodity are usually imperfect substitutes for similar exports from other countries. Consequently, the price elasticity of export demand involves unknown cross elasticities between sub‐groups of the commodity. However, there are constraints on the relative magnitudes of all the sub‐group elasticities. These make it possible to assess the degree to which the whole commodity elasticity divided by the market share is an over‐estimate of the export elasticity.
EVALUATING RETURNS TO RESEARCH IN PASTURE IMPROVEMENT*
Authors: Duncan Ronald C.
Published: April 2012

The objectives of the study reported here were (a) to attempt to identify pasture research findings which have been important for the development of improved pastures in a number of agricultural regions, and (b) to estimate the internal rates of return on the investment in pasture research in these regions. The technique used was the estimation of input‐demand functions for the stock of improved pastures. It is shown that the important research results were mainly the result of research in plant nutrition. Adoption lags were estimated, and these were short by comparison with those usually derived by other methods. Internal rates of return calculated for successful research findings were very high, hut there were important differences between regions.
A SUPPLY FUNCTION FOR DAIRY PRODUCTS
Authors: Mules T.J.
Published: April 2012

Results of an investigation into factors affecting the aggregate supply of dairy products in Australia are presented. Empirical estimates of the parameters of the supply function, using ordinary least squares, indicate that some concept of average prices for dairy products is a more important determinant of supply than ratios of prices of dairy products relative to prices of production substitutes such as beef cattle or sheep and lambs. The empirical results also indicate that the quota‐type effects of the various metropolitan fluid milk schemes are important in determining supply. Effects of new technology on supply could not be quantified due to intercorrelation of explanatory variables.
SOURCES AND USES OF FUNDS IN THE NEW ZEALAND FARM SECTOR
Authors: Stanbridge R.J.
Published: April 2012

The changing pattern of funds sources and uses in the New Zealand farm sector, is summarized, using a flow of funds model. Technical problems of data and definition are discussed. The close relationship between cash farm income and investment is observed, and some indication is given of the extent of aggregate cash withdrawals (drawings) from the sector. The increasing reliance of agriculture on external sources of finance is also apparent.
A NOTE ON THE USE OF A MODIFIED INPUT‐OUTPUT MULTIPLIER FOR LAND USE EVALUATION*
Authors: Douglas J.J.
Published: April 2012

The modified input‐output multiplier is proposed. Some limitations of the multiplier and the results of its application to four major land use industries are discussed.
DISTRIBUTED LAGS AND BARLEY ACREAGE RESPONSE ANALYSIS
Authors: Anderson Kym
Published: April 2012

The need to incorporate production response lags in agricultural supply models is established, and two such lags are considered: the familiar adaptive expectations geometric lag, and a more general polynomial lag. These distributed lag supply response models are applied to Australian barley data for the period 1946‐47 to 1968‐69. A number of statistical problems associated with the adaptive expectations model are discussed, and in particular it is concluded that lags both in the formation of price expectations and in acreage adjustment should be considered when using geometric lag models. While the polynomial lag model does not provide useful results in the present study, its simplicity and flexibility suggest it may be useful in other studies requiring distributed lag models. The short run and long run price elasticity of barley supply estimates are compared with Gruen et al. [14] supply elasticities for the other major rural commodities, from which it appears that barley has a higher short run elasticity but a lower long run elasticity than wheat, wool and meat.
A LINEAR PROGRAMMING SOLUTION TO SOME MARKET ALLOCATION PROBLEMS
Authors: Piggott Roley R.
Published: April 2012

Certain market allocation problems involving linear average net revenue functions can be solved by linear programming. The technique can be applied to an objective function derived from linear marginal net revenue functions, the objective being to force each marginal net revenue as near to zero as possible given the constraint set. If a particular problem is suited to a linear programming solution, researchers may prefer to use this technique rather than more sophisticated optimization methods.
PROBLEMS OF CHANGE IN AUSTRALIAN AGRICULTURAL ECONOMICS
Authors: Musgrave Warren F.
Published: April 2012

There has been a low level of methodological controversy within the Australian agricultural economics profession. Johnson's 1963 paper is the most significant and in it he passed criticisms on agricultural production economists not unlike those currently being made by political economists of economics in general. These past criticisms have in the main been ignored by the Australian profession but it is suggested that they are now being pushed with renewed vigour and they can no longer be ignored. It is argued that our policy work has by and large been successful and effective except for significant areas where our methodology was of restricted usefulness. In farm management the Johnsonian strictures would seem to apply but a more charitable interpretation is provided which should meet the approval of the political economists. Our almost complete neglect of development economics must soon draw to an end and we will find that the methodologies which we have relied on heavily and fairly successfully must be augmented as we become more involved in this field. The political economics challenge should be recognized and accepted with relish because the nature of our work is changing and will continue to change in the future. We have adapted fairly well as adjustment and equity have become major policy concerns. Meeting the political economics challenge will help this process of adaptation.
OPTIMAL FEEDING POLICIES FOR BROILER PRODUCTION: AN APPLICATION OF DYNAMIC PROGRAMMING*
Authors: Kennedy John O.S. , Rofe B.H. , Greig I.D. , Hardaker I.D.
Published: April 2012

The determination of an optimal feeding and selling strategy for broiler production given a space constraint is formulated as a dynamic programming problem. Production equations derived from trial data are used to obtain an optimal sequence of rations in which energy density changes through time. The stability of the plan is explored and the implications of the results for production research and commercial practice are considered.
NO FEELING FOR “UDDERS”?: A CRITICAL NOTE ON THE REPORT OF THE A.C.T. MILK AUTHORITY*
Authors: Albon Robert
Published: April 2012

Fluid milk marketing in Australia is generally associated with an administered system where free market forces are unable to operate due to public intervention. Such interference creates a situation where, as Throsby [6, p. 243] puts it, 'returns to the fluid milk sector are maintained by monopoly pricing and supply control measures which vary from State to State'. The Australian Capital Territory (A.C.T.) is, similarly, not immune to the effects of producer protection. Indeed, it is contended that the implementation of the proposals contained in the A.C.T. Milk Authority Report of March 1974 [3] would have the effect of institutionalizing the power of the dairy industry to act in a manner opposed to the interests of A.C.T. consumers. The basic reason why the interests of consumers are so often put second to those of suppliers is summed up by J.N. Lewis [2, p. 283]: 'A determined close‐knit group with strong interests in a particular policy issue can often impose its desires upon an apathetic majority whose interests are weak and diffused'. It is proposed to develop this theme by looking at the history of milk supply in the A.C.T. as a background to an examination of the Report, an appraisal of its contents, the advocacy of an alternative (competitive) solution and an estimation of costs, to consumers, of producer protection.
ON WHY RATES OF ASSISTANCE DIFFER BETWEEN AUSTRALIA'S RURAL INDUSTRIES*
Authors: Anderson Kym
Published: April 2012

An economic theory of politics is applied to the question of why there are large differences in effective rates of assistance to Australia's rural industries. It is suggested that a major part of the explanation is the different incentives faced by industry lobby groups to demand assistance and by the government to supply assistance. Various determinants of the incentives to demand and supply assistance are hypothesized, and these hypotheses are tested against the existing pattern of rural assistance. The evidence generally supports the hypotheses, and suggests some policy changes to reduce existing government distortions.
THE LABOUR RESPONSE OF QUASI‐SUBSISTENT VILLAGE CRAFTSMEN IN RURAL PAPUA NEW GUINEA*
Authors: Philp Norman E.
Published: April 2012

In this study of labour‐leisure choice, a labour supply equation is derived from a Stone‐Geary utility function and extended to incorporate several 'non‐economic' variables. Such variables are made functions of the 'minimum subsistence' quantities which characterise the standard Stone‐Geary model. The model is then estimated on cross‐sectional data obtained from a field survey of quasi‐subsistent piece rate producer‐consumers living and working in a number of New Guinean villages. Approximately two‐thirds of the observed variation in the weekly work commitment of the sampled workers was explained by the model. The response of cash work commitment to variation in earning rates was found, on average, to be highly inelastic and slightly negative in direction. The econometric approach adopted herein is offered as an alternative to the less formal analyses of Melanesian labour response hitherto undertaken by economic anthropologists.
THE SHORT‐TERM EFFECT OF DOMESTIC OIL PRICE INCREASES ON THE AUSTRALIAN ECONOMY WITH SPECIAL REFERENCE TO THE AGRICULTURAL SECTOR
Authors:   IMPACT Project Staff, Vincent David P. , Dixon Peter B. , Parmenter B.R. , Sams D.C.
Published: April 2012

The rise in the domestic price of oil products implied by the new import parity pricing policy for domestic crude oil is likely to pose some problems for macroeconomic management. In this paper an attempt has been made to quantify the short‐run adjustment problems involved, using the ORANI 78 model of the Australian economy. Results are presented for a range of variables of interest, including macroeconomic variables, industrial and workforce composition and farm incomes. With fixed real wages, farm incomes are projected to decline by between 6 and 8 per cent.
THE DEMAND FOR MEAT — AN EXAMPLE OF AN INCOMPLETE COMMODITY DEMAND SYSTEM*
Authors: Fisher Brian S.
Published: April 2012

Equations describing the demand for beef and veal, mutton, lamb, pork and chicken are estimated using the full information maximum likelihood estimator. Elasticity estimates are presented and the double logarithmic model is compared with a demand system which is derived from the indirect translog utility function. Estimates of the direct price and income elasticities are not particularly sensitive to model specification but the estimated cross‐price elasticities are sensitive to the choice of functional form. The results indicate that the double logarithmic specification may be less satisfactory than the alternative presented in cases where restrictions on the parameters are imposed during estimation.
THE IAC'S APPROACH TO AGRICULTURAL POLICY*
Authors: Edwards G. W.
Published: April 2012

The main recommendations contained in the IAC's reports on rural references are outlined. The Commission's reasoning on four issues that are widely viewed as important to the formulation of rural policy is examined. The four issues are: assistance to industry; terms of trade; uncertainty and instability; and adjustment policy. Criticisms are made of the IAC's argument on these issues, and some inconsistencies between reports are indicated. It is concluded that the IAC has made a valuable contribution to the discussion of rural policy in Australia even though its recommendations are sometimes sounder than the argument offered to support them.