Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2016
Sammendrag
Winching is common in small-scale forest operations, especially on steep slopes, where tractors cannot reach the logs inside the forest. In this case, logs are dragged to the roadside with tractor-mounted winches, for later collection by transportation units. Winching is a heavy task, posing a high physiological stress on winching crew members. The aim of this study was to investigate the relationship between experienced workload, work conditions and operator fitness. The study confirmed the assumption that fit, young operators experience a lower workload than older ones. Workload depends on winching direction, and it is higher when winching downhill than when winching uphill. Results confirmed that gravity is the main factor, and it has a stronger effect than task type and tool weight. Walking uphill with no tools is heavier than walking downhill and carrying a steel cable. As a consequence, tool weight reduction can only palliate the problem, without solving it. Winching crews should be composed of fit, young workers. When the task is assigned to older workers, it is necessary to allow longer rest breaks, accepting a lower productivity. Keywords: steep terrain, winching, workload, heart rate
Forfattere
Knut Arne Smeland Kristian Hovde Liland Jakub Sandak Anna Sandak Lone Ross Thomas Kringlebotn Thiis Ingunn BurudSammendrag
Untreated wooden surfaces degrade when exposed to natural weathering. In this study thin wood samples were studied for weather degradation effects utilising a hyperspectral camera in the near infrared wavelength range in transmission mode. Several sets of samples were exposed outdoors for time intervals from 0 days to 21 days, and one set of samples was exposed to ultraviolet (UV) radiation in a laboratory chamber. Spectra of earlywood and latewood were extracted from the hyperspectral image cubes using a principal component analysis-based masking algorithm. The degradation was modelled as a function of UV solar radiation with four regression techniques, partial least squares, principal component regression, Ridge regression and Tikhonov regression. It was found that all the techniques yielded robust prediction models on this dataset. The result from the study is a first step towards a weather dose model determined by temperature and moisture content on the wooden surface in addition to the solar radiation.
Sammendrag
A total of 967 students (males and females) from four secondary schools in Vysocina region of Czechia were interviewed via 24‐question Likert‐type questionnaire to assess student’s environmental awareness and perceptions. The generalized linear models were used to test if (and to what extent) student perceptions related to environment are/ or not influenced by various factors including gender, age, place of residence, educational level, and specialization. The results showed that students’ age, place of residence, education level and their specialization did not significantly affect (p<0.05) their environmental perceptions. However, gender appeared to be statistically significant (p<0.05) influencing student environmental perceptions and also showed linkages to basic environmental education, attitudes and engagement of students in science-related activities. Our results strongly support the need for more environmental education, awareness campaigns in the schools and engaging students in outdoor environment related activities. Future research should include detail environmental surveys targeting school students across Czechia.
Forfattere
Wenche DramstadSammendrag
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Sammendrag
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Sammendrag
A controlled climatic chamber microcosm experiment was conducted to examine how light affects the hourly sporulation pattern of the beneficial mite pathogenic fungus Neozygites floridana during a 24 h cyclus over a period of eight consecutive days. This was done by inoculating two-spotted spider mites (Tetranychus urticae) with N. floridana and placing them on strawberry plants for death and sporulation. Spore (primary conidia) discharge was observed by using a spore trap. Two light regimes were tested: Plant growth light of 150 μmol m−2 s−1 for 12 h supplied by high pressure sodium lamps (HPS), followed by either; (i) 4 h of 50 μmol m−2 s−1 light with similar HPS lamps followed by 8 h darkness (full HPS light + reduced HPS light + darkness) or (ii) 4 h of 50 μmol m−2 s−1 red light followed by 8 h darkness (full HPS light + red light + darkness). A clear difference in hourly primary conidia discharge pattern between the two different light treatments was seen and a significant interaction effect between light treatment and hour in day during the 24 h cycle was observed. The primary conidia discharge peak for treatment (ii) that included red light was mainly reached within the red light hours (19:00–23:00) and the dark hours (23:00–07:00). The primary conidia discharge peak for treatment (i) with HPS light only was mainly reached within the dark hours (23:00–07:00).
Sammendrag
Ventilation management and the tuber maturity at harvest are essential factors in maintaining potato quality during long-term storage. The aim of this study was to examine the effect of ventilation strategy on storage quality of potato tubers with three different maturity levels at harvest. Two potato cultivars, Saturna and Asterix, were stored in small-scale experimental stores and large-scale commercial stores. Both storage categories were ventilated by both low continuous air rates (natural ventilation) and intermittent high air rates (forced ventilation). The different maturity levels were obtained by a combination of pre-sprouting strategy, planting date and level of nitrogen fertilization of the seed tubers, where pre-sprouting, early planting date and low amount of nitrogen resulted in the most mature tubers. Storage quality parameters investigated during and after long-term storage (6 months in small-scale and 4 months in large-scale stores) included weight loss, respiration, dry matter, sucrose, glucose/fructose content and fry colour. In average over three years natural ventilation resulted in higher weight losses in small- and large-scale stores (1.36 and 3.93%), lower content of reducing sugars (glucose + fructose) in large-scale stores (2.35 mg g 1) and lighter fry colour than did forced ventilation. Immature potatoes had higher weight losses (4.16%), higher respiration rates (1.68 mg CO2 kg 1 h 1) and lower dry matter content (22.3–22.5%) than more mature potatoes. This study show that both maturity and ventilation strategy affects storage quality of potatoes as measured by weight loss, sugar content and fry colour.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
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Forfattere
Dainé Hernández-Ochandia Mayra G. Rodríguez Hernández Ileana Miranda Cabrera Ricardo HolgadoSammendrag
El objetivo de este trabajo fue determinar los métodos más efecientes para la extracción de las comunidades de nematodos presentes en suelos del agrupamiento Ferralíco. Se muestrearon las localidades de Güines y San José de las Lajas, en la provincia Mayabeque, Cuba. El área seleccionada de 1 ha de suelo, se dividió en estratos y de cada uno se tomaron 100 submuestras para conformar cuatro muestras por ha. La toma de muestras se realizó en zig-zag utilizando una barrena; se colocaron en una bolsa de polietileno y se trasladaron al laboratorio de Nematología Agrícola del Centro Nacional de Sanidad Agropecuaria (CENSA).Se utilizaron lastécnicas de Embudos de Baermann, Bandejas Whitehead modificadas (en ambas con filtros de leche y gasa), así como el método de las dos botellas y la técnica de centrifugación flotación. Se procesaron 5, 25, 50, 100, 150, 250 y 350 gramos de suelo, excepto en la técnica de Embudos Barmann, donde se utilizaron 5 y 25g. Los datos del número de especímenes extraídos por muestra se procesaron mediante Análisis de Componentes Principales. Los mayores recobrados se obtuvieron con los métodos de las Bandejas de Whitehead (con ambos filtros)(100g de suelo) y el método de Centrifugación-Flotación