Antennae on transmitters on free-living marine animals: Balancing budgets on the high wire

The effect of externally mounted antennae on the energetics of penguins was studied by mounting various antennae on a transducer fixed to a model Magellanic penguin Spheniscus magellanicus to determine drag, run at speeds of up to 2 m s–1 in a swim canal. For rigid antennae set perpendicular to the water flow, measured drag increased with increasing swim speed. Increasing antenna length (for lengths between 100 and 200 mm) or diameter (for diameters between 1 and 4 mm) resulted in accelerating increased drag as a function of both antenna length and diameter. Where antennae were positioned at acute angles to the water flow, drag was markedly reduced, as was drag at higher speeds in flexible antennae. These results were incorporated in a model on the foraging energetics of free-living Magellanic penguins using data (on swim speeds, intervals between prey encounters, amount ingested per patch and dive durations) derived from previously published work and from a field study conducted on birds from a colony at Punta Norte, Argentina, using data loggers. The field work indicated that free-living birds have a foraging efficiency (net energy gain/net energy loss) of about 2.5. The model predicted that birds equipped with the largest rigid external antennae tested (200 mm × 3 mm diameter), set perpendicular to water flow, increased energy expenditure at normal swim speeds of 1.77 m s–1 by 79% and at prey capture speeds of 2.25 m s–1 by 147%, and ultimately led to a foraging efficiency that was about 5 times less than that of unequipped birds. Highly flexible antennae were shown to reduce this effect considerably. Deleterious antenna-induced effects are predicted to be particularly critical in penguins that have to travel fast to capture prey. Possible measures taken by the birds to increase foraging efficiency could include reduced travelling speed and selection of smaller prey types. Suggestions are made as to how antenna-induced drag might be minimized for future studies on marine diving animal

Approaches to displaying information to assist decisions under uncertainty

The estimation of the costs of a product or project and the decisions based on these forecasts are subject to much uncertainty relating to factors like unknown future developments. This has been addressed repeatedly in research studies focusing on different aspects of uncertainty; unfortunately, this interest has not yet been adopted in practice. One reason can be found in the inadequate representation of uncertainty. This paper introduces an experiment, which engages different approaches to displaying cost forecasting information to gauge the consideration of uncertainty in the subsequent decision-making process. Three different approaches of displaying cost-forecasting information including the uncertainty involved in the data were tested, namely a three point trend forecast, a bar chart, and a FAN-diagram. Furthermore, the effects of using different levels of contextual information about the decision problem were examined. The results show that decision makers tend to simplify the level of uncertainty from a possible range of future outcomes to the limited form of a point estimate. Furthermore, the contextual information made the participants more aware of uncertainty. In addition, the fan-diagram prompted 75.0% of the participants to consider uncertainty even if they had not used this type of diagram before; it was therefore identified as the most suitable method of graphical information display for encouraging decision makers to consider the uncertainty in cost forecasting

Approaches to displaying information to assist decisions under uncertainty

This article was published in the journal, Omega [© Elsevier] and the definitive version is available at: http://dx.doi.org/10.1016/j.omega.2011.05.010The estimation of the costs of a product or project and the decisions based on these forecasts are subject to much uncertainty relating to factors like unknown future developments. This has been addressed repeatedly in research studies focusing on different aspects of uncertainty; unfortunately, this interest has not yet been adopted in practice. One reason can be found in the inadequate representation of uncertainty. This paper introduces an experiment, which engages different approaches to displaying cost forecasting information to gauge the consideration of uncertainty in the subsequent decision-making process. Three different approaches of displaying cost-forecasting information including the uncertainty involved in the data were tested, namely a three point trend forecast, a bar chart, and a FAN-diagram. Furthermore, the effects of using different levels of contextual information about the decision problem were examined. The results show that decision makers tend to simplify the level of uncertainty from a possible range of future outcomes to the limited form of a point estimate. Furthermore, the contextual information made the participants more aware of uncertainty. In addition, the fan-diagram prompted 75.0% of the participants to consider uncertainty even if they had not used this type of diagram before; it was therefore identified as the most suitable method of graphical information display for encouraging decision makers to consider the uncertainty in cost forecasting

Effects of expanding cassava planting and harvesting windows on root yield, starch content and revenue in southwestern Nigeria

Open Access Article; Published online: 28 Jul 2022Cassava (Manihot esculenta Crantz) is an important staple crop in Nigeria. It provides approximately 80 % of the caloric intake in Nigeria. High starch content and fresh root yields are important for the commercialization of cassava. Cassava is a perennial crop, and it can be produced all year round. However, cassava fresh root yield and starch content are strongly influenced by environmental conditions such as rainfall. Therefore, it is important to identify planting and harvest periods to attain maximum yields and starch content and to increase profitability. The present study aimed at (i) comparing changes in fresh root yields and starch contents of cassava planted and harvested at different times around the year (ii) identifying the cassava harvest phase attaining maximum fresh root yields and starch content (iii) assessing how price fluctuations and root yields affect the revenue and income generation across the year. This study was carried from 2017 to 2019 in southwestern Nigeria. Existing cassava fields planted at different months were visited and the planting dates were recorded. Harvesting for each planting month was done at 9, 11 and 13 months after planting (MAP). Fresh root yield and starch content varied across planting months. For all crop ages, the highest fresh root yields were recorded when planted in September and December. The highest root starch content was observed in 9- and 13-months old cassava when planted in March and November, respectively. Cassava fresh root yield and starch content varied across Julian day of harvest with lowest yields obtained between Julian day 60–120 (March and April) which coincides with the beginning of rainfall. Highest fresh root yields and starch content were attained between Julian day 180–330. Revenue showed seasonal variation and was dependent Julian day of harvest. Gross revenue was lowest between Julian day 60 and 120 (March and April) and highest from Julian day 180 (July). Lowest incomes or profits were recorded when cassava was harvested between Julian day 60 and 120 (March and April). About 9.1 % of farmers had negative revenues or lost income when they harvested at 9 MAP hence losing between 150 and 200 USD ha−1 compared with 2.8 % of farmers that lost income when harvesting was done at 11 and 13 MAP losing between 100 and 150 USD ha−1. Thus, farmers’ income generation critically depends on cassava planting and harvest dates. Choosing the right time to plant and harvest cassava is one of the most important decisions farmers can make to maximize profit

Cassava-maize intercropping systems in southern Nigeria: radiation use efficiency, soil moisture dynamics, and yields of component crops

Open Access Article; Published online: 30 Apr 2022Efficient utilization of incident solar radiation and rainwater conservation in rain-fed smallholder cropping systems require the development and adoption of cropping systems with high resource use efficiency. Due to the popularity of cassava-maize intercropping and the food security and economic importance of both crops in Nigeria, we investigated options to improve interception of photosynthetically active radiation (IPAR), radiation use efficiency (RUE), soil moisture retention, and yields of cassava and maize in cassava-maize intercropping systems in 8 on-farm researcher-managed multi-location trials between 2017 and 2019 in different agro-ecologies of southern Nigeria. Treatments were a combination of (1) maize planting density (low density at 20,000 maize plants ha-1 versus high density at 40,000 maize plants ha-1, intercropped with 12,500 cassava plants ha-1); (2) fertilizer application and management targeting either the maize crop (90 kg N, 20 kg P and 37 kg K ha-1) or the cassava crop (75 kg N, 20 kg P and 90 kg K ha-1), compared with control without fertilizer application. Cassava and maize development parameters were highest in the maize fertilizer regime, resulting in the highest IPAR at high maize density. The combined intercrop biomass yield was highest at high maize density in the maize fertilizer regime. Without fertilizer application, RUE was highest at low maize density. However, the application of the maize fertilizer regime at high maize density resulted in the highest RUE, soil moisture content, and maize grain yield. Cassava storage root yield was higher in the cassava fertilizer regime than in the maize fertilizer regime. We conclude that improved IPAR, RUE, soil moisture retention, and grain yield on nutrient-limited soils of southern Nigeria, or in similar environments, can be achieved by intercropping 40,000 maize plants ha-1 with 12,500 cassava plants ha-1 and managing the system with the maize fertilizer regime. However, for higher cassava storage root yield, the system should be managed with the cassava fertilizer regime

Developing recommendations for increased productivity in cassava-maize intercropping systems in southern Nigeria

Open Access Article; Published online: 31 Aug 2021Cassava-maize intercropping is a common practice among smallholder farmers in Southern Nigeria. It provides food security and early access to income from the maize component. However, yields of both crops are commonly low in farmers’ fields. Multi-locational trials were conducted in Southern Nigeria in 2016 and 2017 to investigate options to increase productivity and profitability through increased cassava and maize plant densities and fertilizer application. Trials with 4 and 6 treatments in 2016 and 2017, respectively were established on 126 farmers’ fields over two seasons with a set of different designs, including combinations of two levels of crop density and three levels of fertilizer rates. The maize crop was tested at low density (LM) with 20,000 plants ha−1 versus high density (HM) with 40,000 plants ha−1. For cassava, low density (LC) had had 10,000 plants ha−1 versus the high density (HC) with 12,500 plants ha−1.; The fertilizer application followed a regime favouring either the maize crop (FM: 90 kg N, 20 kg P and 37 kg K ha−1) or the cassava crop (FC: 75 kg N, 20 kg P and 90 kg K ha−1), next to control without fertilizer application (F0). Higher maize density (HM) increased marketable maize cob yield by 14 % (3700 cobs ha−1) in the first cycle and by 8% (2100 cobs ha−1) in the second cycle, relative to the LM treatment. Across both cropping cycles, fertilizer application increased cob yield by 15 % (5000 cobs ha−1) and 19 % (6700 cobs ha−1) in the FC and FM regime, respectively. Cassava storage root yield increased by 16 % (4 Mg ha−1) due to increased cassava plant density, and by 14 % (4 Mg ha−1) due to fertilizer application (i.e., with both fertilizer regimes) but only in the first cropping cycle. In the second cycle, increased maize plant density (HM) reduced cassava storage root yield by 7% (1.5 Mg ha−1) relative to the LM treatment. However, the negative effect of high maize density on storage root yield was counteracted by fertilizer application. Fresh storage root yield increased by 8% (2 Mg ha−1) in both fertilizer regimes compared to the control without fertilizer application. Responses to fertilizer by cassava and maize varied between fields. Positive responses tended to decline with increasing yields in the control treatment. The average value-to-cost ratio (VCR) of fertilizer use for the FM regime was 3.6 and higher than for the FC regime (VCR = 1.6), resulting from higher maize yields when FM than when FC was applied. Revenue generated by maize constituted 84–91% of the total revenue of the cropping system. The highest profits were achieved with the FM regime when both cassava and maize were grown at high density. However, fertilizer application was not always advisable as 34 % of farmers did not realize a profit. For higher yields and profitability, fertilizer recommendations should be targeted to responsive fields based on soil fertility knowledge

Klimafolgenabschätzungen in der Wasserwirtschaft und deren Nutzen für die Praxis

KlimafolgenClimate ImpactsDer globale Klimawandel kann regional unterschiedliche Auswirkungen haben. Während sich die wissenschaftliche Forschung vor allem mit der Analyse der Daten beschäftigt, ist die fachliche Praxis darum bemüht, die Ergebnisse zu interpretieren und Handlungsempfehlungen daraus abzuleiten. Im Zuge des Projektes KliBiW (Globaler Klimawandel – Wasserwirtschaftliche Folgenabschätzung für das Binnenland) wurden die Auswirkungen des Klimawandels auf die Hochwasser- und Niedrigwasserverhältnisse in Niedersachsen untersucht. Hierzu wurden die Daten von zwei regionalen Klimamodellen (WETTREG2006 und REMO), beide angetrieben durch das Globalmodell ECHAM5/MPI-OM, räumlich interpoliert und die Niederschläge zum Teil zeitlich disaggregiert, um hoch aufgelöste Klimainformationen bereitzuhalten. Anschließend erfolgte die Kopplung mit einem hydrologischen Modellsystem (PANTA RHEI), das bereits in der Hochwasservorhersagezentrale des NLWKN im Einsatz ist. Über Langzeitsimulationen wurden zukünftige Veränderungen in den Abflussverhältnissen räumlich und zeitlich differenziert für das Aller-Leine Gebiet identifiziert. Als Betrachtungszeiträume dienten eine nahe Zukunftsphase (2021 – 2050) und eine ferne Zukunftsphase (2071 – 2100). Die Veränderungen verschiedener hydrologischer Hoch- und Niedrigwasser-Kenngrößen wurden gegenüber einem Kontrollzeitraum (1971 – 2000) aufgezeigt. Die Auswertungen an 8 Pegeln in Einzugsgebieten >1.000 km² auf Tageswertbasis und an 6 Pegeln in Einzugsgebieten <1.000 km² auf Stundenwertbasis zeigten, dass sich die Hochwassersituation zukünftig verschärfen kann. Während kleinere Hochwässer häufiger auftreten können, nehmen die Scheitelabflüsse insbesondere in der fernen Zukunft zu. Aussagen zu größeren Ereignissen sind aufgrund der großen Bandbreite der Ergebnisse jedoch mit erheblichen Unsicherheiten behaftet. Die Niedrigwasserverhältnisse zeigten eine Abnahme der Abflüsse, speziell im Sommer, sowie eine Zunahme der Dauer undnder Volumendefizite bei Trockenperioden. Hierbei erschien die Variabilität und Ausprägung der Trockenheit in kleineren Einzugsgebieten etwas größer. Die Nutzung dieser Erkenntnisse stellt die fachliche Praxis vor die Herausforderung, die Ergebnisse zu interpretieren und zu kommunizieren. Unsicherheiten in den Modellketten müssen berücksichtigt und, wenn möglich, quantifiziert werden. Die abgeleiteten hydrologischen Konsequenzen des Klimawandels können z.B. Anwendung finden in der gesetzlich geforderten Berücksichtigung der Auswirkungen des Klimawandels auf die Risikogebiete entsprechend der Hochwasserrisikomanagement-Richtlinie (2007/60/EG). Dieser Beitrag gibt einen Überblick über wasserwirtschaftlich relevante Auswertungen von Klimamodelldaten auf unterschiedlichen räumlichen Skalen und zeigt anhand ausgewählter Beispiele auf, wie primär im wissenschaftlichen Kontext erhobene Ergebnisse effektiv für praxisrelevante Fragestellungen genutzt werden können

Brain blood vessel autoantibodies in patients with NMDA and GABAA receptor encephalitis: identification of unconventional Myosin-X as target antigen

INTRODUCTION: The antibody repertoire from CSF-derived antibody-secreting cells and memory B-cells in patients with encephalitis contains a considerable number of antibodies that do not target the disease-defining autoantigen such as the GABA or NMDA receptors. This study focuses on the functional relevance of autoantibodies to brain blood vessels in patients with GABAA and NMDA receptor encephalitis. METHODS: We tested 149 human monoclonal IgG antibodies from the cerebrospinal fluid of six patients with different forms of autoimmune encephalitis on murine brain sections for reactivity to blood vessels using immunohistochemistry. Positive candidates were tested for reactivity with purified brain blood vessels, effects on transendothelial electrical resistance (TEER), and expression of tight junction proteins as well as gene regulation using human brain microvascular endothelial hCMEC/D3 cells as in vitro blood-brain barrier model. One blood-vessel reactive antibody was infused intrathecally by pump injection in mice to study in vivo binding and effects on tight junction proteins such as Occludin. Target protein identification was addressed using transfected HEK293 cells. RESULTS: Six antibodies reacted with brain blood vessels, three were from the same patient with GABAAR encephalitis, and the other three were from different patients with NMDAR encephalitis. One antibody from an NMDAR encephalitis patient, mAb 011-138, also reacted with cerebellar Purkinje cells. In this case, treatment of hCMEC/D3 cells resulted in decreased TEER, reduced Occludin expression, and mRNA levels. Functional relevance in vivo was confirmed as Occludin downregulation was observed in mAb 011-138-infused animals. Unconventional Myosin-X was identified as a novel autoimmune target for this antibody. DISCUSSION: We conclude that autoantibodies to blood vessels occur in autoimmune encephalitis patients and might contribute to a disruption of the blood-brain barrier thereby suggesting a potential pathophysiological relevance of these antibodies