Toward a script theory of guidance in computer-supported collaborative learning

This article presents an outline of a script theory of guidance for computer-supported collaborative learning (CSCL). With its four types of components of internal and external scripts (play, scene, role, and scriptlet) and seven principles, this theory addresses the question how CSCL practices are shaped by dynamically re-configured internal collaboration scripts of the participating learners. Furthermore, it explains how internal collaboration scripts develop through participation in CSCL practices. It emphasizes the importance of active application of subject matter knowledge in CSCL practices, and it prioritizes transactive over non-transactive forms of knowledge application in order to facilitate learning. Further, the theory explains how external collaboration scripts modify CSCL practices and how they influence the development of internal collaboration scripts. The principles specify an optimal scaffolding level for external collaboration scripts and allow for the formulation of hypotheses about the fading of external collaboration scripts. Finally, the article points towards conceptual challenges and future research questions

Antiferromagnetically coupled CoFeB/Ru/CoFeB trilayers

This work reports on the magnetic interlayer coupling between two amorphous CoFeB layers, separated by a thin Ru spacer. We observe an antiferromagnetic coupling which oscillates as a function of the Ru thickness x, with the second antiferromagnetic maximum found for x=1.0 to 1.1 nm. We have studied the switching of a CoFeB/Ru/CoFeB trilayer for a Ru thickness of 1.1 nm and found that the coercivity depends on the net magnetic moment, i.e. the thickness difference of the two CoFeB layers. The antiferromagnetic coupling is almost independent on the annealing temperatures up to 300 degree C while an annealing at 350 degree C reduces the coupling and increases the coercivity, indicating the onset of crystallization. Used as a soft electrode in a magnetic tunnel junction, a high tunneling magnetoresistance of about 50%, a well defined plateau and a rectangular switching behavior is achieved.Comment: 3 pages, 3 figure

The Effects of Medium Chain Fatty Acids in Mash and Crumbled Pellet Diets on Growth Performance of Broilers

The objective of this experiment was to determine the effects of medium chain fatty acids (MCFA) in mash and crumbled pellet broiler diets. A total of 400 male chicks (Cobb 500; initial BW 0.092 lb) were housed in 4 Petersime batteries and used in an 18-d study. Treatments were randomly assigned to 80 cages within location block resulting in 8 cages per treatment with 5 chicks per cage at placement. Treatments were arranged in a 2 × 5 factorial with main effects of feed type (mash and crumbled pellet) and 0.5% MCFA inclusion (no inclusion, control; hexanoic acid, C6; octanoic acid, C8; decanoic acid, C10; and dodecanoic acid, C12). Fat inclusions in the diets were equalized using 0.5% soybean oil in the control diet. Prior to crumbling, diets were conditioned at 185°F for approximately 20 s and pelleted (CPM, model CL-5, Crawfordsville, IN) with a 5/32 × 7/8 in. ring die. Dietary treatments were fed for the full duration of the study. There was no evidence of feed form × MCFA interactions. From d 0 to 18, chicks fed pelleted diets had improved (P \u3c 0.001) body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), and final BW compared to those fed mash diets. For the overall treatment period, there was no evidence of a MCFA effect (P \u3e 0.10) on broiler performance. Pelleting and crumbling feed improved growth performance regardless of MCFA inclusion. The MCFA inclusion did not positively influence growth performance of broilers

Interface sharpening in CoFeB magnetic tunnel junctions

We report grazing incidence x-ray scattering evidence for sharpening of the interface between amorphous Co60Fe20B20 and AlOx during in situ annealing below the Co60Fe20B20 crystallization temperature. Enhancement of the interference fringe amplitude in the specular scatter and the absence of changes in the diffuse scatter indicate that the sharpening is not a reduction in topological roughness but a reduction in the width of the chemical composition profile across the interface. The temperature at which the sharpening occurs corresponds to that at which a maximum is found in the tunneling magnetoresistance of magnetic tunnel junctions

Effects of Grinding Almond Hulls with a Hammermill on Particle Size and Bulk Density

The objective of this experiment was to evaluate the effects of grinding almond hulls with different screens on subsequent particle size and bulk density. Twenty pounds of almond hulls from the California Central Valley were ground with a laboratory-scale 1.5 HP Bliss Hammermill (Model 6K630B) using a 7/16 in., 3/4 in., 1 in., or no screen. Each screen size treatment was ground at three separate time points to provide three replications per treatment. For each replication, two samples were collected and analyzed for particle size geometric mean and standard deviation and bulk density. Geometric mean particle size was greater (P \u3c 0.01) when no screen was used to grind almond hulls compared with 3/4-in. and 1-in. screens; moreover, particle size was decreased (P \u3c 0.01) when ground with a 7/16 in. screen compared to all other treatments. Particle standard deviation did not differ (P = 0.13) between treatments. Bulk density of almond hulls tended to be greater (P = 0.07) when a 7/16-in. screen was used as compared to no screen, a 3/4-in. screen, and a 1-in. screen. Overall, unground almond hulls had a bulk density of 14.1 lb/ft3. Therefore, grinding almond hulls using a 7/16 in., 3/4 in., 1 in., or no screen led to an increase in their bulk density by 140, 115, 114, and 111%, respectively. Particle size was also evaluated using the Penn State Particle Separator. Grinding almond hulls with no screen tended (P \u3c 0.01) to increase proportions of medium (i.e., 0.31 to 0.75 in.) particles and decrease (P ≤ 0.02) proportions of fine (i.e., \u3c 0.16 in.) particles compared to grinding with a 7/16-in. screen. In conclusion, decreasing hammermill screen size reduced particle size from 2217 µm to 1324 µm but did not impact particle size standard deviation. In addition, grinding almond hulls increased bulk density by 111 to 140%. A live-bottom trailer with a load capacity of 2,835 ft3 could transport approximately 20 tons of unprocessed almond hulls. Conversely, the same trailer could transport 25 to 30 tons of ground almond hulls, thus, reducing transportation costs by 20 to 33% per ton, respectively

Estimating the Net Energy Value of Expelled, Extruded Soybean Meal When Fed to Nursery Pigs

Solvent-extracted soybean meal (SSBM) is typically used as the primary protein source in swine diets in the United States. Mechanically extracted or expelled soybean meal (MSBM) typically has increased concentrations of fat and decreased concentrations of essential AA compared to SSBM, but MSBM has been demonstrated to have improved AA digestibility. This study aimed to estimate the NE value of MSBM relative to SSBM and to determine its effects on growth performance of late nursery pigs. A total of 297 pigs (241 × 600, DNA) were weaned (BW 11.2 lb) and placed into 60 pens (2 rooms of 30 pens) with 5 pigs per pen balanced by gender and weaning weight. Pigs were fed a common diet for 21 days. Then, pens of pigs (BW 20.7 lb) were randomly assigned to one of five treatments to provide 12 replications per treatment. Treatments consisted of increasing amounts of MSBM replacing SSBM in the diet (0, 25, 50, 75, and 100%). All diets were fed for 28 days and were formulated to 1.30% standardized ileal digestible lysine, and met or exceeded NRC2 recommendations for Lys:AA, Ca, and P. The SSBM has an NRC2 NE value of 946 kcal/lb and the 0% MSBM diet was formulated to 1091 kcal/lb and NE was not balanced between diets. Analyzed values for CP, ether extract, crude fiber, and total Lys for the SSBM were 47.28%, 0.47%, 3.80%, and 3.00%, respectively, while the MSBM contained 47.41%, 6.88%, 5.32%, and 2.99% respectively. The MSBM had increased values for KOH solubility and trypsin inhibitor (83.62 and 7026 TIU/g, respectively) compared to the SSBM (73.05 and 3011 TIU/g, respectively) while urease activity was similar between the two (0.03 vs. 0.02 Δ pH, respectively). Data were analyzed using PROC GLIMMIX (SAS v. 9.4) with pen as the experimental unit and room as the blocking factor. There was no evidence of differences in ADG and ADFI in pigs fed diets with increasing concentrations of MSBM. Pigs fed diets with increasing concentrations of MSBM had improved (linear, P \u3c 0.001) F/G and caloric efficiency on an NE basis. In conclusion, using caloric efficiency to estimate NE of the MSBM relative to SSBM, MSBM was estimated to have a value of 123% of SSBM NE or 1,164 kcal/lb. This increase in NE resulted in improved feed efficiency of nursery pigs

Evaluation of Pellet Binders on Pellet Durability Index of a High-Fat Swine Diet

The objective of this study was to evaluate the addition of different pellet binders on pellet quality of a grower swine diet by measuring pellet durability index (PDI). Dietary treatments consisted of a corn-soybean meal-based control diet with 20% dried distillers grains with solubles and 4% choice white grease, the control diet with 0.6% lignosulfonate (AMERI-BOND 2X; LignoTech USA Inc.; Rothschild, WI), or the control diet with increasing levels of a pasta by-product (2.5, 5.0, or 10.0%; International Ingredients, St. Louis, MO). Pellet binders were added to the control diet in the place of corn to create dietary treatments. Each treatment was pelleted in 333 lb batches at 3 separate periods to provide 3 replications per treatment. Pelleting run was considered the experimental unit and time of processing served as the blocking factor. Order of pelleting dietary treatments was randomized within each time period. Corn was ground to approximately 600 μm. Diets were pelleted via steam conditioning (10- × 55-in. Wenger twin staff conditioner, Model 150) and using a 30-horsepower pellet mill (1012-2 HD Master Model, California Pellet Mill) with a 5/32- × 1-in. pellet die. During each processing run, pellet samples were collected throughout the run and immediately placed in an experimental counter-flow cooler for 10 minutes. After cooling, samples were analyzed for pellet durability index using the Holmen NHP 100 (TekPro Ltd, Norfolk, UK) for 30 seconds. There was no evidence (P \u3e 0.172) of difference for the effect of treatment on conditioner temperature, hot pellet temperature, or production rate. The average conditioner temperature, hot pellet temperature, and production rate were 185.9°F, 188.2°F, and 1,364 lb/h, respectively. The diet containing lignosulfate improved (P \u3c 0.001) PDI compared to the control diet. Increasing pasta by-product from 2.5 to 10% increased the PDI (P \u3c 0.01) compared with the control diet. Diets containing 2.5% pasta by-product had lower PDI compared to those with lignosulfonate, diets with 5% pasta by-product and lignosulfonate had similar PDI, and diets containing 10% pasta by-product had increased PDI compared to the lignosulfonate treatment. In conclusion, adding pellet binders to the high fat finisher diets improved PDI by 7.4 to 10.7%. Adding 5% pasta by-product improved PDI similar to that of lignosulfonate and adding 10% pasta by-product further improved PDI compared to lignosulfonate

S-COL: A Copernican turn for the development of flexibly reusable collaboration scripts

Collaboration scripts are usually implemented as parts of a particular collaborative-learning platform. Therefore, scripts of demonstrated effectiveness are hardly used with learning platforms at other sites, and replication studies are rare. The approach of a platform-independent description language for scripts that allows for easy implementation of the same script on different platforms has not succeeded yet in making the transfer of scripts feasible. We present an alternative solution that treats the problem as a special case of providing support on top of diverse Web pages: In this case, the challenge is to trigger support based on the recognition of a Web page as belonging to a specific type of functionally equivalent pages such as the search query form or the results page of a search engine. The solution suggested has been implemented by means of a tool called S-COL (Scripting for Collaborative Online Learning) and allows for the sustainable development of scripts and scaffolds that can be used with a broad variety of content and platforms. The tool’s functions are described. In order to demonstrate the feasibility and ease of script reuse with S-COL, we describe the flexible re-implementation of a collaboration script for argumentation in S-COL and its adaptation to different learning platforms. To demonstrate that a collaboration script implemented in S-COL can actually foster learning, an empirical study about the effects of a specific script for collaborative online search on learning activities is presented. The further potentials and the limitations of the S-COL approach are discussed