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result(s) for
"Six, Magdalena"
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The effect of information on the quality of decisions
2014
We study the effect of additional information on the quality of decisions. We define the extreme case of complete information about probabilities as our reference scenario. There, decision makers (DMs) can use expected utility theory to evaluate the best alternative. Starting from the worst case—where DMs have no information at all about probabilities—we find a method of constantly increasing the information by systematically limiting the ranges of the probabilities. In our simulation-based study, we measure the effects of the constant increase in information by using different forms of relative volumes. We define these as the relative volumes of the gradually narrowing areas which lead to the same (or a similar) decision as with the probability in the reference scenario. Thus, the relative volumes account for the quality of information. Combining the quantity and quality of information, we find decreasing returns to scale on information, or in other words, the costs of gathering additional information increase with the level of information. Moreover, we show that more available alternatives influence the decision process negatively. Finally, we analyze the quality of decisions in processes where more states of nature are considered. We find that this degree of complexity in the decision process also has a negative influence on the quality of decisions.
Journal Article
Information as potential key determinant in switching electricity suppliers
by
Wirl, Franz
,
Six, Magdalena
,
Wolf, Jaqueline
in
Accounting/Auditing
,
Business and Management
,
Business Taxation/Tax Law
2017
In this paper, we investigate the drivers and obstacles to switch the electricity supplier for Austrian households. Since the liberalization of the market in 2001, the annual switching rates have remained at surprisingly low levels, leading to a loss of significant savings potential for Austrian households. The results of our exploratory study suggest that the knowledge about tariffs and electricity suppliers is the driving force for the decision to switch. The lack of information might also explain the low incentive effect of savings potentials. Thus, we suggest that for price competitive electricity suppliers, it might be more effective to familiarize customers with tariff structures and savings potentials than to advertise with “green electricity” as it is the common strategy at the moment.
Journal Article
Information as potential key determinant in switching electricity suppliers
by
Wirl, Franz
,
Six, Magdalena
,
Wolf, Jaqueline
in
Electricity distribution
,
Suppliers
,
Switching
2017
In this paper, we investigate the drivers and obstacles to switch the electricity supplier for Austrian households. Since the liberalization of the market in 2001, the annual switching rates have remained at surprisingly low levels, leading to a loss of significant savings potential for Austrian households. The results of our exploratory study suggest that the knowledge about tariffs and electricity suppliers is the driving force for the decision to switch. The lack of information might also explain the low incentive effect of savings potentials. Thus, we suggest that for price competitive electricity suppliers, it might be more effective to familiarize customers with tariff structures and savings potentials than to advertise with “green electricity” as it is the common strategy at the moment.
Journal Article
Simulation of a regional soil nitrogen balance in Swiss croplands
by
Six, Johan
,
Necpálová, Magdalena
,
Calitri, Francesca
in
Agricultural land
,
Agricultural practices
,
Agricultural production
2020
Nitrogen (N) management in cropping systems needs adjustments because constraints to crop production are mostly related to high inputs and low recovery of N fertilizers. We used the
DayCent
model to predict regional N inputs, outputs, and balances of Swiss soils under (1) a range of N fertilizer input levels (0–300% of recommended crop-specific rates) and (2) organic fertilization, reduced tillage or cover cropping at the recommended input of N. The crops included wheat, maize, and root/tuber crops and legumes. Decreasing N inputs reduced the environmental impact by 13.5–51.3 kg N ha
-
1
, but it also reduced the yield by 6.8–44.8 kg N ha
-
1
. Increasing N inputs led to an increase in yield by 5.6–29.5 kg N ha
-
1
, but with additional losses of 14.9–181.8 kg N ha
-
1
into the environment. Harvested crop N and
NO
3
-
leaching accounted for 30–59% and 27–62% of fertilizer-derived changes in total N output, respectively. Converting conventional to organic cropping led to a mean increase in soil N balance by 0.3–62.6 kg N ha
-
1
. The soil N balance increased the most by using partially decomposed organic fertilizer in combination with cover cropping and reduced tillage. However, this positive N balance was mainly due to a reduction in N removal with harvest and
NO
3
-
leaching. The use of highly decomposable organic matter and cover cropping did not lead to any N yield penalty while decreasing
NO
3
-
leaching. These results highlight that organic practices combined with reduced tillage and cover cropping can optimize the use and recovery of N resources.
Journal Article
Modeling integrated soil fertility management for maize production in Kenya using a Bayesian calibration of the DayCent model
by
Necpalova, Magdalena
,
Vanlauwe, Bernard
,
Ndungu, Samuel Mathu
in
Agricultural production
,
Analysis
,
Bayesian analysis
2024
Sustainable intensification schemes such as integrated soil fertility management (ISFM) are a proposed strategy to close yield gaps, increase soil fertility, and achieve food security in sub-Saharan Africa. Biogeochemical models such as DayCent can assess their potential at larger scales, but these models need to be calibrated to new environments and rigorously tested for accuracy. Here, we present a Bayesian calibration of DayCent, using data from four long-term field experiments in Kenya in a leave-one-site-out cross-validation approach. The experimental treatments consisted of the addition of low- to high-quality organic resources, with and without mineral nitrogen fertilizer. We assessed the potential of DayCent to accurately simulate the key elements of sustainable intensification, including (1) yield, (2) the changes in soil organic carbon (SOC), and (3) the greenhouse gas (GHG) balance of CO2 and N2O combined. Compared to the initial parameters, the cross-validation showed improved DayCent simulations of maize grain yield (with the Nash–Sutcliffe model efficiency (EF) increasing from 0.36 to 0.50) and of SOC stock changes (with EF increasing from 0.36 to 0.55). The simulations of maize yield and those of SOC stock changes also improved by site (with site-specific EF ranging between 0.15 and 0.38 for maize yield and between −0.9 and 0.58 for SOC stock changes). The four cross-validation-derived posterior parameter distributions (leaving out one site each) were similar in all but one parameter. Together with the model performance for the different sites in cross-validation, this indicated the robustness of the DayCent model parameterization and its reliability for the conditions in Kenya. While DayCent poorly reproduced daily N2O emissions (with EF ranging between −0.44 and −0.03 by site), cumulative seasonal N2O emissions were simulated more accurately (EF ranging between 0.06 and 0.69 by site). The simulated yield-scaled GHG balance was highest in control treatments without N addition (between 0.8 and 1.8 kg CO2 equivalent per kg grain yield across sites) and was about 30 % to 40 % lower in the treatment that combined the application of mineral N and of manure at a rate of 1.2 t C ha−1 yr−1. In conclusion, our results indicate that DayCent is well suited for estimating the impact of ISFM on maize yield and SOC changes. They also indicate that the trade-off between maize yield and GHG balance is stronger in low-fertility sites and that preventing SOC losses, while difficult to achieve through the addition of external organic resources, is a priority for the sustainable intensification of maize production in Kenya.
Journal Article
Managing soil organic carbon in tropical agroecosystems: evidence from four long-term experiments in Kenya
by
Necpalova, Magdalena
,
Vanlauwe, Bernard
,
Couëdel, Antoine
in
Agricultural ecosystems
,
Agricultural land
,
Agricultural practices
2023
In sub-Saharan Africa, maize is one of the most important staple crops, but long-term maize cropping with low external inputs has been associated with the loss of soil fertility. While adding high-quality organic resources combined with mineral fertilizer has been proposed to counteract this fertility loss, the long-term effectiveness and interactions with site properties still require more understanding. This study used repeated measurements over time to assess the effect of different quantities and qualities of organic resource addition combined with mineral nitrogen (N) on the change of soil organic carbon (SOC) contents over time (and SOC stocks in the year 2021) in four ongoing long-term experiments in Kenya. These experiments were established with identical treatments in moist to dry climates, on coarse to clayey soil textures, and have been conducted for at least 16 years. They received organic resources in quantities equivalent to 1.2 and 4 t C ha−1 yr−1 in the form of Tithonia diversifolia (high quality, fast turnover), Calliandra calothyrsus (high quality, intermediate turnover), Zea mays stover (low quality, fast turnover), sawdust (low quality, slow turnover) and local farmyard manure (variable quality, intermediate turnover). Furthermore, the addition of 240 kg N ha−1 yr−1 as mineral N fertilizer or no fertilizer was the split-plot treatment. At all four sites, a loss of SOC was predominantly observed, likely because the sites had been converted to cropland only a few decades before the start of the experiments. Across sites, the average decline of SOC content over 19 years in the 0 to 15 cm topsoil layer ranged from 42 % to 13 % of the initial SOC content for the control and the farmyard manure treatments at 4 t C ha−1 yr−1, respectively. Adding Calliandra or Tithonia at 4 t C ha−1 yr−1 limited the loss of SOC contents to about 24 % of initial SOC, while the addition of sawdust, maize stover (in three of the four sites) and sole mineral N addition showed no significant reduction of SOC loss over the control. Site-specific analyses, however, did show that at the site with the lowest initial SOC content (about 6 g kg−1), the addition of 4 t C ha−1 yr−1 farmyard manure or Calliandra with mineral N led to a gain in SOC contents. The other sites lost SOC in all treatments, albeit at site-specific rates. While subsoil SOC stocks in 2021 were little affected by organic resource additions (no difference in three of the four sites), the topsoil SOC stocks corroborated the results obtained from the SOC content measurements (0–15 cm) over time. The relative annual change of SOC contents showed a higher site specificity in farmyard manure, Calliandra and Tithonia treatments than in the control treatment, suggesting that the drivers of site specificity in SOC buildup (soil mineralogy, soil texture, climate) need to be better understood for effective targeting management of organic resources. Farmyard manure showed the highest potential for reducing SOC losses, but the necessary quantities to build SOC are often not realistic for smallholder farmers in Africa. Therefore, additional agronomic interventions such as intercropping, crop rotations or the cultivation of crops with extended root systems are necessary to maintain or increase SOC.
Journal Article
Synergistic Effects of Nanomedicine Targeting TNFR2 and DNA Demethylation Inhibitor—An Opportunity for Cancer Treatment
by
Ferji, Khalid
,
Elkord, Eyad
,
Plebanski, Magdalena
in
Antineoplastic Agents - pharmacology
,
Antineoplastic Agents - therapeutic use
,
Cancer therapies
2019
Tumor necrosis factor receptor 2 (TNFR2) is expressed on some tumor cells, such as myeloma, Hodgkin lymphoma, colon cancer and ovarian cancer, as well as immunosuppressive cells. There is increasingly evidence that TNFR2 expression in cancer microenvironment has significant implications in cancer progression, metastasis and immune evasion. Although nanomedicine has been extensively studied as a carrier of cancer immunotherapeutic agents, no study to date has investigated TNFR2-targeting nanomedicine in cancer treatment. From an epigenetic perspective, previous studies indicate that DNA demethylation might be responsible for high expressions of TNFR2 in cancer models. This perspective review discusses a novel therapeutic strategy based on nanomedicine that has the capacity to target TNFR2 along with inhibition of DNA demethylation. This approach may maximize the anti-cancer potential of nanomedicine-based immunotherapy and, consequently, markedly improve the outcomes of the management of patients with malignancy.
Journal Article