Abstract Towards New Measures of Information Retrieval Evaluation

All of the methods cumently used to evaluate information retrieval (Ill) systems have limitations in their ability to measure how well users are able to acquire information. We utilized on approach to assessing information obtained based on the user’s ability to answer qtrcstions from a shortanswer test. Senior medical students took the ten-question test and then searched one of (WO IR systems on the five questions for which they were least ccrtuin of their answer. Our results showed thtit pre-searching scores on the test were low but that searching yielded a high proportion of answers with both systems. These methods are able to measure information obtained, and will be used in subsequent studies to assess differences among IR systems

Agronomic Comparison of Anhydrous Ammonia Applied with a High Speed-Low Draft Opener and Conventional Knife Injection in Corn

Anhydrous ammonia (AA) is an important N fertilizer in the U.S., and with large farming operations rapid application is needed. This study evaluated the impact of AA application timing and N rates when applied with a high speed low draft (HSLD) or a conventional till knife (CTKI) on corn (Zea Mays L.) production in no-tillage fields. The study was conducted at sites located in Illinois, Iowa, and Kansas from 2007 to 2009. The experimental design was a split-plot factorial arrangement of application method, timing (fall; spring preplant, SP; and sidedress, SD), and five N rates. Fall AA application was least efficient (mean 55 kg N ha–1 higher optimum N and 2% lower grain yield, GY), with SP and SD equivalent. The HSLD was comparable to the CTKI with most applications, except when high N rates (180 and 225 kg N ha-1) were applied SP. For these treatments AA injury reduced plant population (PP), early season growth, canopy NDVI, and GY. Seedling injury did not occur with any N rate or timing with the CTKI. Shallow AA placement at high speed with the HSLD can provide a viable alternative to traditional deeper knife injection when conditions are suitable for AA application and positioning avoids corn seedling injury. Anhydrous ammonia application with the HSLD, however, should be avoided where high SP AA rates may be placed directly under future corn rows.This is a manuscript of an article from Agronomy Journal 106 (2014): 881, doi: 10.2134/agronj13.0441. Posted with permission.</p

Agronomic comparison of anhydrous ammonia applied with a high speed-low draft opener and conventional knife injection in corn

Citation: Woli, Krishna P., Fabián G. Fernández, John E. Sawyer, Joshua D. Stamper, David B. Mengel, Daniel W. Barker, and Mark H. Hanna. “Agronomic Comparison of Anhydrous Ammonia Applied with a High Speed-Low Draft Opener and Conventional Knife Injection in Corn.” Agronomy Journal 106, no. 3 (2014): 881–92. https://doi.org/10.2134/agronj13.0441.Anhydrous ammonia (AA) is an important N fertilizer in the U.S., and with large farming operations rapid application is needed. This study evaluated the impact of AA application timing and N rates when applied with a high speed low draft (HSLD) or a conventional till knife (CTKI) on corn (Zea Mays L.) production in no-tillage fields. The study was conducted at sites located in Illinois, Iowa, and Kansas from 2007 to 2009. The experimental design was a split-plot factorial arrangement of application method, timing (fall; spring preplant, SP; and sidedress, SD), and five N rates. Fall AA application was least efficient (mean 55 kg N haˉ¹ higher optimum N and 2% lower grain yield, GY), with SP and SD equivalent. The HSLD was comparable to the CTKI with most applications, except when high N rates (180 and 225 kg N haˉ¹) were applied SP. For these treatments AA injury reduced plant population (PP), early season growth, canopy NDVI, and GY. Seedling injury did not occur with any N rate or timing with the CTKI. Shallow AA placement at high speed with the HSLD can provide a viable alternative to traditional deeper knife injection when conditions are suitable for AA application and positioning avoids corn seedling injury. Anhydrous ammonia application with the HSLD, however, should be avoided where high SP AA rates may be placed directly under future corn rows

A potato model intercomparison across varying climates and productivity levels

A potato crop multimodel assessment was conducted to quantify variation among models and evaluate responses to climate change. Nine modeling groups simulated agronomic and climatic responses at low-input (Chinoli, Bolivia and Gisozi, Burundi)- and high-input (Jyndevad, Denmark and Washington, United States) management sites. Two calibration stages were explored, partial (P1), where experimental dry matter data were not provided, and full (P2). The median model ensemble response outperformed any single model in terms of replicating observed yield across all locations. Uncertainty in simulated yield decreased from 38% to 20% between P1 and P2. Model uncertainty increased with interannual variability, and predictions for all agronomic variables were significantly different from one model to another (P < 0.001). Uncertainty averaged 15% higher for low- vs. high-input sites, with larger differences observed for evapotranspiration (ET), nitrogen uptake, and water use efficiency as compared to dry matter. A minimum of five partial, or three full, calibrated models was required for an ensemble approach to keep variability below that of common field variation. Model variation was not influenced by change in carbon dioxide (C), but increased as much as 41% and 23% for yield and ET, respectively, as temperature (T) or rainfall (W) moved away from historical levels. Increases in T accounted for the highest amount of uncertainty, suggesting that methods and parameters for T sensitivity represent a considerable unknown among models. Using median model ensemble values, yield increased on average 6% per 100-ppm C, declined 4.6% per °C, and declined 2% for every 10% decrease in rainfall (for nonirrigated sites). Differences in predictions due to model representation of light utilization were significant (P < 0.01). These are the first reported results quantifying uncertainty for tuber/root crops and suggest modeling assessments of climate change impact on potato may be improved using an ensemble approach