394 research outputs found
Changes and Problems of Agricultural Development in Iran
There has been a big debate on the evolution of agricultural development (AD), the challenges and problems hindering AD in Iran since last decade. This study was implemented in the province of Esfahan and a number of 130 out of 212 agricultural experts from 13 different townships were selected as the target group. Totally 70 experts returned the completed questionnaires. The findings of the study revealed that most of the AD changes have been positive but in a very slow rate. Respondents unanimously claimed that the sustainability in agriculture and maintenance of agricultural lands are the most deteriorating issues during last ten years. With regard to AD problems, they stressed the lack of adequate fund allocated to the Ministry of Agriculture (MAJ) and lack of its power to control beneficiary dealers within the sector, unfair political influence, lack of international contacts and also untrustworthiness of agriculture for private investors as the most problematic obstacles for AD in Iran. They perceived that MAJ has not sufficiently addressed the problems so far, although, there are some promising movements. Experts believed that MAJ is not able to solve the majority of problems alone due to their extrinsic nature
Teaching and Learning in Interdisciplinary Higher Education: A Systematic Review
Interdisciplinary higher education aims to develop boundary-crossing skills, such as interdisciplinary thinking. In the present review study, interdisciplinary thinking was defined as the capacity to integrate knowledge of two or more disciplines to produce a cognitive advancement in ways that would have been impossible or unlikely through single disciplinary means. It was considered as a complex cognitive skill that constituted of a number of subskills. The review was accomplished by means of a systematic search within four scientific literature databases followed by a critical analysis. The review showed that, to date, scientific research into teaching and learning in interdisciplinary higher education has remained limited and explorative. The research advanced the understanding of the necessary subskills of interdisciplinary thinking and typical conditions for enabling the development of interdisciplinary thinking. This understanding provides a platform from which the theory and practice of interdisciplinary higher education can move forwar
Interdisciplinary thinking in agricultural and life sciences higher education
Interdisciplinary thinking as a skill appears to be of value to higher education students and those in employment. This idea is explored with reference to the agricultural and life sciences. The need for further understanding of the development of interdisciplinary thinking is acknowledged. This is closely related to the requirement for well-founded curriculum and course design. This publication presents a brief introduction to a systematic review of scientific research into teaching and learning in interdisciplinary higher education. While tentative, the understanding arising from the review findings is considered to be of potential value to educational practice. A selection of the review findings is presented by way of illustration. The selection is believed to be of relevance to the agricultural and life sciences. The review findings presented here take the form of interdisciplinary thinking sub skills and enabling condition
Effects of precipitation uncertainty on discharge calculations for main river basins
This study quantifies the uncertainty in discharge calculations caused by uncertainty in precipitation input for 294 river basins worldwide. Seven global gridded precipitation datasets are compared at river basin scale in terms of mean annual and seasonal precipitation. The representation of seasonality is similar in all datasets, but the uncertainty in mean annual precipitation is large, especially in mountainous, arctic, and small basins. The average precipitation uncertainty in a basin is 30%, but there are strong differences between basins. The effect of this precipitation uncertainty on mean annual and seasonal discharge was assessed using the uncalibrated dynamic global vegetation and hydrology model Lund-Potsdam-Jena managed land (LPJmL), yielding even larger uncertainties in discharge (average 90%). For 95 basins (out of 213 basins for which measurements were available) calibration of model parameters is problematic because the observed discharge falls within the uncertainty of the simulated discharge. A method is presented to account for precipitation uncertainty in discharge simulations
Effects of precipitation uncertainty on discharge calculations for main river basins
This study quantifies the uncertainty in discharge calculations caused by uncertainty in precipitation input for 294 river basins worldwide. Seven global gridded precipitation datasets are compared at river basin scale in terms of mean annual and seasonal precipitation. The representation of seasonality is similar in all datasets, but the uncertainty in mean annual precipitation is large, especially in mountainous, arctic, and small basins. The average precipitation uncertainty in a basin is 30%, but there are strong differences between basins. The effect of this precipitation uncertainty on mean annual and seasonal discharge was assessed using the uncalibrated dynamic global vegetation and hydrology model Lund-Potsdam-Jena managed land (LPJmL), yielding even larger uncertainties in discharge (average 90%). For 95 basins (out of 213 basins for which measurements were available) calibration of model parameters is problematic because the observed discharge falls within the uncertainty of the simulated discharge. A method is presented to account for precipitation uncertainty in discharge simulations
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Accounting for environmental flow requirements in global water assessments
As the water requirement for food production and other human needs grows, quantification of environmental flow requirements (EFRs) is necessary to assess the amount of water needed to sustain freshwater ecosystems. EFRs are the result of the quantification of water necessary to sustain the riverine ecosystem, which is calculated from the mean of an environmental flow (EF) method. In this study, five EF methods for calculating EFRs were compared with 11 case studies of locally assessed EFRs. We used three existing methods (Smakhtin, Tennant, and Tessmann) and two newly developed methods (the variable monthly flow method (VMF) and the Q90-Q50 method). All methods were compared globally and validated at local scales while mimicking the natural flow regime. The VMF and the Tessmann methods use algorithms to classify the flow regime into high, intermediate, and low-flow months and they take into account intra-annual variability by allocating EFRs with a percentage of mean monthly flow (MMF). The Q90-Q50 method allocates annual flow quantiles (Q90 and Q50) depending on the flow season. The results showed that, on average, 37% of annual discharge was required to sustain environmental flow requirement. More water is needed for environmental flows during low-flow periods (46-71% of average low-flows) compared to high-flow periods (17-45% of average high-flows). Environmental flow requirements estimates from the Tennant, Q90-Q50, and Smakhtin methods were higher than the locally calculated EFRs for river systems with relatively stable flows and were lower than the locally calculated EFRs for rivers with variable flows. The VMF and Tessmann methods showed the highest correlation with the locally calculated EFRs (R2 = 0.91). The main difference between the Tessmann and VMF methods is that the Tessmann method allocates all water to EFRs in low-flow periods while the VMF method allocates 60% of the flow in low-flow periods. Thus, other water sectors such as irrigation can withdraw up to 40% of the flow during the low-flow season and freshwater ecosystems can still be kept in reasonable ecological condition. The global applicability of the five methods was tested using the global vegetation and the Lund-Potsdam-Jena managed land (LPJmL) hydrological model. The calculated global annual EFRs for fair ecological conditions represent between 25 and 46% of mean annual flow (MAF). Variable flow regimes, such as the Nile, have lower EFRs (ranging from 12 to 48% of MAF) than stable tropical regimes such as the Amazon (which has EFRs ranging from 30 to 67% of MAF)
Reconciling irrigated food production with environmental flows for Sustainable Development Goals implementation
Safeguarding river ecosystems is a precondition for attaining the UN Sustainable Development Goals (SDGs) related to water and the environment, while rigid implementation of such policies may hamper achievement of food security. River ecosystems provide life-supporting functions that depend on maintaining environmental flow requirements (EFRs). Here we establish gridded process-based estimates of EFRs and their violation through human water withdrawals. Results indicate that 41% of current global irrigation water use (997 km3 per year) occurs at the expense of EFRs. If these volumes were to be reallocated to the ecosystems, half of globally irrigated cropland would face production losses of ≥10%, with losses of ∼20–30% of total country production especially in Central and South Asia. However, we explicitly show that improvement of irrigation practices can widely compensate for such losses on a sustainable basis. Integration with rainwater management can even achieve a 10% global net gain. Such management interventions are highlighted to act as a pivotal target in supporting the implementation of the ambitious and seemingly conflicting SDG agenda
Online discussion compensates for suboptimal timing of supportive information presentation in a digitally supported learning environment
This study used a sequential set-up to investigate the consecutive effects of timing of supportive information presentation (information before vs. information during the learning task clusters) in interactive digital learning materials (IDLMs) and type of collaboration (personal discussion vs. online discussion) in computer-supported collaborative learning (CSCL) on student knowledge construction. Students (N = 87) were first randomly assigned to the two information presentation conditions to work individually on a case-based assignment in IDLM. Students who received information during learning task clusters tended to show better results on knowledge construction than those who received information only before each cluster. The students within the two separate information presentation conditions were then randomly assigned to pairs to discuss the outcomes of their assignments under either the personal discussion or online discussion condition in CSCL. When supportive information had been presented before each learning task cluster, online discussion led to better results than personal discussion. When supportive information had been presented during the learning task clusters, however, the online and personal discussion conditions had no differential effect on knowledge construction. Online discussion in CSCL appeared to compensate for suboptimal timing of presentation of supportive information before the learning task clusters in IDLM
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