The von Bertalanffy growth model for horticulture : Predicting tomato size at harvest

Traditionally, crop load and fruit yield from previous seasons are used as indicators for prediction of fruit size. Disregarding the inevitable biological variation between fruit, von Bertalanffy (1938) described the growth, expressed as length, of virtually any living organism. The model is here extended to include the variation between individuals in a batch. Using this extended model, fruit size and its variation can be predicted, using measurements of a large number of fruit at a single point during early development. The diameter of 200 tomatoes was measured 15 days after full bloom (DAFB). Using the density function derived from the extended von Bertalanffy model, and applying prior knowledge of some of the model parameters, the variation in size at harvest could be predicted. Validation of the results was obtained by comparing the predicted sizes with the diameters of the same tomatoes at harvest

From fruitlet to harvest : Modelling and predicting size and its distributions for tomato, apple and pepper fruit

Size is an important property of all fruit as it determines, together with crop load, fruit yield. The aim of this study is to model the increase in fruit size during cell expansion based on diameter or length and to predict fruit size and volume, including the variation in size and volume, at harvest. The size of individual fruit during growth of fruit (four apple, two tomato and six pepper cultivars) was measured from early fruit set until harvest at several seasons. Size data were evaluated as diameter and length using the von Bertalanffy growth model, adapted to include the variation in size between individuals and the effect of growing temperature. The adapted von Bertalanffy model describes the increase in diameter and length and their variation. For any fruit type, size increased along the same generic growth model. A single stochastic variable, the biological shift factor, was sufficient to describe the variation in development time, initial size and maximum size. For all batches the percentage variation explained for were well over 93% with growth rate constants similar per species and only a minor effect of growing temperature.Prediction of the maximum size distribution based on measurements half way the cell expansion period is explored and discussed. Size and its distribution can be predicted based on a single measuring point in time but with two or three points in time the prediction system becomes more robust

Variation in paediatric hospital antibiotic guidelines in Europe

Objective: To assess the availability and source of guidelines for common infections in European paediatric hospitals and determine their content and characteristics. Design: Participating hospitals completed an online questionnaire on the availability and characteristics of antibiotic prescribing guidelines and on empirical antibiotic treatment including duration of therapy for 5 common infection syndromes: respiratory tract, urinary tract, skin and soft tissue, osteoarticular and sepsis in neonates and children. Results: 84 hospitals from 19 European countries participated in the survey of which 74 confirmed the existence of guidelines. Complete guidelines (existing guidelines for all requested infection syndromes) were reported by 20% of hospitals and the majority (71%) used a range of different sources. Guidelines most commonly available were those for urinary tract infection (UTI) (74%), neonatal sepsis (71%) and sepsis in children (65%). Penicillin and amoxicillin were the antibiotics most commonly recommended for respiratory tract infections (RTIs) (up to 76%), cephalosporin for UTI (up to 50%) and for skin and soft tissue infection (SSTI) and bone infection (20% and 30%, respectively). Antistaphylococcal penicillins were recommended for SSTIs and bone infections in 43% and 36%, respectively. Recommendations for neonatal sepsis included 20 different antibiotic combinations. Duration of therapy guidelines was mostly available for RTI and UTI (82%). A third of hospitals with guidelines for sepsis provided recommendations for length of therapy. Conclusions: Comprehensive antibiotic guideline recommendations are generally lacking from European paediatric hospitals. We documented multiple antibiotics and combinations for most infections. Considerable improvement in the quality of guidelines and their evidence base is required, linking empirical therapy to resistance rates

Variation in paediatric hospital antibiotic guidelines in Europe

Objective: To assess the availability and source of guidelines for common infections in European paediatric hospitals and determine their content and characteristics. Design: Participating hospitals completed an online questionnaire on the availability and characteristics of antibiotic prescribing guidelines and on empirical antibiotic treatment including duration of therapy for 5 common infection syndromes: respiratory tract, urinary tract, skin and soft tissue, osteoarticular and sepsis in neonates and children. Results: 84 hospitals from 19 European countries participated in the survey of which 74 confirmed the existence of guidelines. Complete guidelines (existing guidelines for all requested infection syndromes) were reported by 20% of hospitals and the majority (71%) used a range of different sources. Guidelines most commonly available were those for urinary tract infection (UTI) (74%), neonatal sepsis (71%) and sepsis in children (65%). Penicillin and amoxicillin were the antibiotics most commonly recommended for respiratory tract infections (RTIs) (up to 76%), cephalosporin for UTI (up to 50%) and for skin and soft tissue infection (SSTI) and bone infection (20% and 30%, respectively). Antistaphylococcal penicillins were recommended for SSTIs and bone infections in 43% and 36%, respectively. Recommendations for neonatal sepsis included 20 different antibiotic combinations. Duration of therapy guidelines was mostly available for RTI and UTI (82%). A third of hospitals with guidelines for sepsis provided recommendations for length of therapy. Conclusions: Comprehensive antibiotic guideline recommendations are generally lacking from European paediatric hospitals. We documented multiple antibiotics and combinations for most infections. Considerable improvement in the quality of guidelines and their evidence base is required, linking empirical therapy to resistance rates

The worldwide antibiotic resistance and prescribing in european children (ARPEC) point prevalence survey : Developing hospital-quality indicators of antibiotic prescribing for children

Objectives: Previously, web-based tools for cross-sectional antimicrobial point prevalence surveys (PPSs) have been used in adults to develop indicators of quality improvement. We aimed to determine the feasibility of developing similar quality indicators of improved antimicrobial prescribing focusing specifically on hospitalized neonates and children worldwide. Methods: A standardized antimicrobial PPS method was employed. Included were all inpatient children and neonates receiving an antimicrobial at 8:00 am on the day of the PPS. Denominators included the total number of inpatients. A web-based application was used for data entry, validation and reporting. We analysed 2012 data from 226 hospitals (H) in 41 countries (C) from Europe (174H; 24C), Africa (6H; 4C), Asia (25H; 8C), Australia (6H), Latin America (11H; 3C) and North America (4H). Results: Of 17 693 admissions, 6499 (36.7%) inpatients received at least one antimicrobial, but this varied considerably between wards and regions. Potential indicators included very high broad-spectrum antibiotic prescribing in children of mainly ceftriaxone (ranked first in Eastern Europe, 31.3%; Asia, 13.0%; Southern Europe, 9.8%), cefepime (ranked third in North America, 7.8%) and meropenem (ranked first in Latin America, 13.1%). The survey identified worryingly high use of critically important antibiotics for hospital-acquired infections in neonates (34.9%; range from 14.2% in Africa to 68.0% in Latin America) compared with children (28.3%; range from 14.5% in Africa to 48.9% in Latin America). Parenteral administration was very common among children in Asia (88%), Latin America (81%) and Europe (67%). Documentation of the reasons for antibiotic prescribing was lowest in Latin America (52%). Prolonged surgical prophylaxis rates ranged from 78% (Europe) to 84% (Latin America). Conclusions: Simple web-based PPS tools provide a feasible method to identify areas for improvement of antibiotic use, to set benchmarks and to monitor future interventions in hospitalized neonates and children. To our knowledge, this study has derived the first global quality indicators for antibiotic use in hospitalized neonates and children