1,721,207 research outputs found
Shoot Growth Parameters of Potato Seedlings are Determined by Light and Temperature Conditions
No full textCorporate social responsibility and hybrid potato breeding: balancing economic, environmental and social challenges
Full text linkHybrid potato breeding is an emerging technology that can have a strong impact on the potato sector by replacing seed potatoes with true seeds. The Netherlands is a world leader in certified seed potatoes and a number of Dutch companies play a pivotal role in the development of this technology. This implies a certain responsibility for the consequences and conditions of its implementation and we therefore explored how Dutch potato breeding companies see their role and responsibility especially in low- and middle-income countries in the context of the United Nations Sustainable Development Goals (SDGs). From interviews, it appears that most potato breeding companies emphasise the promising role of hybrid potato breeding in achieving SDGs. They also stress that their core business is at the heart of corporate social responsibility as it contributes to the SDGs. We also observed that for the introduction of new varieties they often rely on trickle-down mechanisms, where local farmers are rather passive recipients, rather than being actively involved in strategic choices of innovation. It may explain why the concept of responsible research and innovation (RRI), which emphasises the active involvement of society and affected stakeholders, is relatively unknown in the sector. The main approach in the sector may be labelled as a ‘solution strategy’ where dominant actors rely on their expertise to solve problems. However, the attainment of SDGs should rather be considered as a wicked problem, characterised by complexity, uncertainty and multiple actor’s perspectives. A ‘negotiation strategy’, which is more inclusive and stresses the need of negotiation between different perspectives and interests, may fit better. From the perspective of RRI it is argued that insights from participatory breeding and farmer variety selection traditions and the concept of benefit sharing may be considered as promising negotiation strategies that can contribute to potato breeding practices for the attainment of SDGs.Ethics & Philosophy of Technolog
Hemp (Cannabis sativa L.) leaf photosynthesis in relation to nitrogen content and temperature: implications for hemp as a bio-economically sustainable crop
Full text linkHemp (Cannabis sativa L.) may be a suitable crop for the bio-economy as it requires low inputs while producing a high and valuable biomass yield. With the aim of understanding the physiological basis of hemp's high resource-use efficiency and yield potential, photosynthesis was analysed on leaves exposed to a range of nitrogen and temperature levels. Light-saturated net photosynthesis rate (Amax) increased with an increase in leaf nitrogen up to 31.2 ± 1.9 Î1⁄4mol mâ2 sâ1 at 25 °C. The Amax initially increased with an increase in leaf temperature (TL), levelled off at 25â35 °C and decreased when TL became higher than 35 °C. Based on a C3 leaf photosynthesis model, we estimated mesophyll conductance (gm), efficiency of converting incident irradiance into linear electron transport under limiting light (Îo2LL), linear electron transport capacity (Jmax), Rubisco carboxylation capacity (Vcmax), triose phosphate utilization capacity (Tp) and day respiration (Rd), using data obtained from gas exchange and chlorophyll fluorescence measurements at different leaf positions and various levels of incident irradiance, CO2 and O2. The effects of leaf nitrogen and temperature on photosynthesis parameters were consistent at different leaf positions and among different growth environments except for Îo2LL, which was higher for plants grown in the glasshouse than for those grown outdoors. Model analysis showed that compared with cotton and kenaf, hemp has higher photosynthetic capacity when leaf nitrogen is <2.0 g N mâ2. The high photosynthetic capacity measured in this study, especially at low nitrogen level, provides additional evidence that hemp can be grown as a sustainable bioenergy crop over a wide range of climatic and agronomic conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Agroclimatic analysis: a tool for planning sustainable durum wheat (Triticum turgidum var. durum) production in Ethiopia
No full textLong-term weather data for six locations representing different eco-regions of Ethiopia were analyzed to generate information for appropriate management practices and research priorities of durum wheat (Triticum turgidum var. durum) in Ethiopia. Among the weather elements examined, rainfall was variable and seasonal. The annual rainfall showed a random year-to-year variation both in space and time. Rainfall distribution during the growing period was much more variable than the seasonal total, resulting in a limited growing period. Dependable rainfall is much lower than the mean, particularly for the low-rainfall regions (Asmara, Metahara and Melkasa).
A close relationship between the amount of rainfall and the length of the growing season was observed. The beginning of the rainy season (planting time) ranged from early June to mid-July and the end of growing season varied from early September to November. The growing season (moisture-available period) ranged from 60 days (Metahara) to 140 days (Debre Markos). The results suggest that crop improvement strategies and cropping systems for sustainable durum wheat production should be designed for the different climatic-soil zones based on a realistic assessment of prevailing weather conditions
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Simulating nitrogen management impacts on maize production in the U.S. Midwest
No full textNutrient loss reduction strategies have recently been developed in the U.S. Midwest to decrease the environmental footprint associated with nitrogen (N) fertilizer use. Although these strategies generally suggest decreasing N rates and shifting the timing of N application from fall to spring, the spatiotemporal impacts of these practices on maize yield and fertilizer N use efficiency (NUE, kg grain yield increase per kg N applied) have not been assessed at the watershed scale using crop simulation models. We simulated the effects of N fertilizer rate (0, 168, 190, 224 kg N ha-1) and application timing [fall-applied N (FN): 100% N applied on 1 December; spring-applied N (SN): 100% N applied 10 days before planting; split N: 66% N applied on 1 December + 34% N applied 10 days before planting] on maize grain yield (GY) across 3042 points in Illinois during 2011–2015 using the DSSAT-CERES-Maize model. When simulations were scaled up to the watershed level, results suggest that increases in average maize GY for SN compared to FN occurred in years with higher than average winter rainfall (2011, 2013), whereas yields were similar (+/- 4%) in 2012, 2014, and 2015. Accordingly, differences in NUE for SN compared to FN were small (0.0–1.4 kg GY/kg N) when cumulative winter rainfall was 500 mm at both 168 kg N ha-1 and 224 kg N ha-1. The combined practice of reducing N fertilizer amounts from 224 kg N ha-1 to 190 kg N ha-1 and shifting from FN to SN resulted in a wide range of yield responses during 2011–2015, with the probability of increasing yields varying from 70% of simulation points within a watershed. Positive impacts on both GY and NUE occurred in only 60% of simulations for this scenario, highlighting the challenge of simultaneously improving yield and NUE with a 15% N rate reduction in this region.</div
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