Is the photometric method using acetone extracts to determine chlorophyll concentrations applicable to Mg‐deficient plants?

A conventional photometric method to determine chlorophyll concentrations in maize leaves was evaluated. It was tested whether in Mg‐deficient plant tissue the addition of MgCO₃ during pigment extraction converts protoporphyrin IX into chlorophyll, falsifying concentration measurements. The non‐destructive N‐tester was used as a reference for the destructive chlorophyll determination. It is shown that both methods are valid for the determination of chlorophyll concentration in Mg‐deficient leaves.     

A participatory scenario method to explore the future of marine social‐ecological systems

Anticipating future changes in marine social‐ecological systems (MSES) several decades into the future is essential in the context of accelerating global change. This is challenging in situations where actors do not share common understandings, practices, or visions about the future. We introduce a dedicated scenario method for the development of MSES scenarios in a participatory context. The objective is to allow different actors to jointly develop scenarios which contain their multiple visions of the future. The method starts from four perspectives: “fisheries management,” “ecosystem,” “ocean climate,” and “global context and governance” for which current status and recent trends are summarized. Contrasted scenarios about possible futures are elaborated for each of the four single perspectives before being integrated into multiple‐perspective scenarios. Selected scenarios are then developed into storylines. Focusing on individual perspectives until near the end allows actors with diverse cultures, interests and horizons to confront their own notions of the future. We illustrate the method with the exploration of the futures of the Barents Sea MSES by 2050. We emphasize the following lessons learned: first, many actors are not familiar with scenario building and attention must be paid to explaining the purpose, methodology, and benefits of scenarios exercises. Second, although the Barents Sea MSES is relatively well understood, uncertainties about its future are significant. Third, it is important to focus on unlikely events. Fourth, all perspectives should be treated equally. Fifth, as MSES are continuously changing, we can only be prepared for future changes if we collectively keep preparing.     

An online operational alert system for the early detection of shrimp epidemics at the regional level based on real-time production

Diseases are among the greatest threats affecting the sustainability of shrimp aquaculture. In Ecuador, diseases of cultured shrimp have been quickly transmitted from one region to another. Therefore, an early detection system of impending epidemics could serve as an important management tool for the aquaculture sector. We developed a system for the early detection of shrimp epidemics for the largest shrimp zone of Ecuador based on production surveillance. The system, called Epidemiological Alert System and Aquaculture Management (SAEMA), uses a geographical information system (GIS) with an imaginary grid cartography (12,860 ha per grid) dividing the study area. A production and management index is calculated with the harvest data of each pond. A standardized deviation around the historical averages and an alert level is calculated per grid and month. Normal conditions of production and therefore the absence of disease are depicted in green and yellow. While, orange and red colours express a disease warning manifested through suboptimal production levels. As a result, a map of the study area with grid divisions is displayed, with a specific alert colour for each grid where information is available. SAEMA was developed as a Web application (http://www.saema.espol.edu.ec) that enables producers to record data via a worksheet format using any web browser. Instantaneously, the applications perform a calculation of the alert index and provide feedback to the alert levels displayed in an interactive map. A feedback process was initiated in May 2006 with 19 participating shrimp farms. The objective of this research is to develop a platform for an early detection of shrimp epidemics on a regional scale. The detection of an epidemic, expressed as suboptimal production in a specific region, can provide producers from other zones and government authorities to engage in time preventive and control measures in order to reduce the spread of diseases.     

Frequency of soy food consumption and serum isoflavone concentrations among Chinese women in Shanghai

OBJECTIVE: The food-frequency questionnaire (FFQ) can be an efficient tool to evaluate dietary intake in large, population-based studies, especially for specific foods. The objective of this study was to validate the assessment of soy and isoflavone (daidzein and genistein) intakes, measured by an FFQ, by comparing intakes with serum isoflavone concentrations. DESIGN AND SETTING: Soy and isoflavone intakes and serum isoflavone concentrations were determined as part of a case-control study of dietary factors and risks of benign breast disease and breast cancer. The FFQ, administered during an in-person interview, included six soy-specific line items. Blood was drawn within one week of FFQ completion. SUBJECTS: In total, 1823 women living in Shanghai, People's Republic of China. RESULTS: In this population, soybean milk, fresh bean curd and other bean foods were eaten once per week, and fermented bean curd, fried bean curd puff and soybeans were eaten less than once per week. A significant linear trend (P<0.01) in serum isoflavone concentrations across increasing categories of soy and isoflavone intakes was observed, indicating that soy and isoflavone intakes, measured by the FFQ, well distinguished serum isoflavone concentrations. Linear trends were also observed in both case and control groups in stratified analyses, suggesting little differential bias by case-control status. CONCLUSIONS: The results suggest that the FFQ provides a useful marker of soy food consumption and isoflavone exposure in this population.     

Nitrogen pools and cycles in Tibetan <Emphasis Type="Italic">Kobresia</Emphasis> pastures depending on grazing

Kobresia grasslands on the Tibetan Plateau comprise the world’s largest pastoral alpine ecosystem. Overgrazing-driven degradation strongly proceeded on this vulnerable grassland, but the mechanisms behind are still unclear. Plants must balance the costs of releasing C to soil against the benefits of accelerated microbial nutrient mineralization, which increases their availability for root uptake. To achieve the effect of grazing on this C-N exchange mechanism, a ¹⁵NH₄⁺ field labeling experiment was implemented at grazed and ungrazed sites, with additional treatments of clipping and shading to reduce belowground C input by manipulating photosynthesis. Grazing reduced gross N mineralization rates by 18.7%, similar to shading and clipping. This indicates that shoot removal by grazing decreased belowground C input, thereby suppressing microbial N mining and overall soil N availability. Nevertheless, NH₄⁺ uptake rate by plants at the grazed site was 1.4 times higher than at the ungrazed site, because plants increased N acquisition to meet the high N demands of shoot regrowth (compensatory growth: grazed > ungrazed). To enable efficient N uptake and regrowth, Kobresia plants have developed specific traits (i.e., efficient above-belowground interactions). These traits reflect important mechanisms of resilience and ecosystem stability under long-term moderate grazing in an N-limited environment. However, excessive (over)grazing might imbalance such C-N exchange and amplify plant N limitation, hampering productivity and pasture recovery over the long term. In this context, a reduction in grazing pressure provides a sustainable way to maintain soil fertility, C sequestration, efficient nutrient recycling, and overall ecosystem stability.     

Smartphone adoption and use in agriculture: empirical evidence from Germany

Precision Agriculture - Smartphone technology is promising for the future development of agriculture, as it can facilitate and improve many operational procedures and can also be combined with...     

Priority questions for the science,policy and practice of cultural landscapes in Europe

Context

The design of effective responses to safeguard cultural landscape values in Europe needs collaborative action among the stakeholders involved. Despite considerable progress triggered by the European Landscape Convention (ELC) and other initiatives to link landscape science, policy and practice, a joint research–action agenda is still lacking.

Objectives and methods

We respond to this challenge by identifying common priority questions for the sustainable management of cultural landscapes in Europe. To this end, we gathered, in a first phase, the most relevant research questions through a Delphi-like process with the research community in this field. In a second phase, the questions were prioritized by three stakeholder groups: scientists (Ss), policy-makers (PMs) and practitioners (Ps). The importance ranks and the similarity between groups’ priorities were calculated and analyzed.

Results

We found that the research question that addressed the issue of how to secure sustainable cultural landscapes where they are not economically profitable was the most important, with high level of agreement among all stakeholders. Alignment among the three groups was generally high; being higher between Ps–Ss and Ps–PMs than between Ss and PMs.

Conclusions

Our exercise can assist the implementation of the ELC by outlining the potential direction of future applied research and by strengthening the ties between the multiple stakeholders involved in the stewardship of European cultural landscapes.

     

Hemodynamic effects of an intravenous infusion of medetomidine at six different dose regimens in isoflurane-anesthetized dogs

This study investigated the dose dependency of the hemodynamic effects of IV medetomidine (MED) constant-rate infusion (CRI) during isoflurane anesthesia. Twenty-four healthy beagles randomly received one of six MED CRI regimens. A loading dose of MED was administered IV at 0.2, 0.5, 1.0, 1.7, 4.0, or 12.0 ug/kg-1 for 10 minutes, followed by a maintenance CRI providing identical dose amounts over 60 minutes. Heart rate and mean arterial blood pressure were recorded, blood gases were analyzed, and cardiac index (CI) was determined. Statistical analysis involved a repeated measures linear model. Baseline CI demonstrated a dose-dependent decrease as the MED dose increased, with decreases of 14.9% (SD, 12.7%), 21.7% (17.9%), 27.1% (13.2%), 44.2% (9.7%), 47.9% (8.1%), and 61.2% (14.1%) at doses of 0.2, 0.5, 1.0, 1.7, 4.0, and 12.0 ug/kg-1, respectively. The four lowest doses induced limited and transient changes in heart rate, mean arterial pressure, and CI. Further investigation into potential perioperative uses of MED CRI is warranted.