High-intensity acute exercise and directed forgetting on memory function

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Background and Objectives: Despite accumulating research demonstrating that acute exercise may enhance memory function, very little research has evaluated whether acute exercise can effectuate intentional directed forgetting (DF), an adaptative strategy to facilitate subsequent memory performance. Materials and Methods: A three-arm parallel-group randomized controlled intervention was employed. Participants were randomized into one of three groups, including: (1) exercise plus DF (Ex + DF), (2) DF (directed forgetting) only (DF) and (3) R (remember) only (R). The acute bout of exercise included 15 min of high-intensity treadmill exercise. The memory assessment involved the presentation of two-word lists. After encoding the first word list, participants were either instructed to forget all of those words (DF) or to remember them. Following this, participants encoded the second word list. Results: We observed a statistically significant main effect for list F(1, 57) = 12.27, p \u3c 0.001, η2 p = 0.18, but no main effect for group F(2, 57) = 1.32, p = 0.27, η2 p = 0.04, or list by group interaction, F(2, 57) = 2.89, p = 0.06, η2 p = 0.09. Conclusion: This study demonstrates a directed forgetting effect in that cueing an individual to forget a previously encoded list of items facilitates memory performance on a subsequent list of items. However, we failed to demonstrate any beneficial effect of acute exercise in facilitating directed forgetting. These findings are discussed in the context of directed forgetting theories, particularly the attention inhibition mechanism, as well as the timing of the acute bout of exercise

SimPhysics

Understanding and interpreting relationships and functional trends with 2-D graphs are foundational skills in STEM fields, in other sciences and in all disciplines that utilize data analysis. Introductory physics courses regularly start with the topic of kinematics which heavily utilizes 2-D graphs that describe motion. This is why difficulties that students face in understanding 2-D graphs surface early on in physics. Yet, for this same reason kinematics can be used as a great opportunity to teach graphing skills in general. The primary goal of this project is to develop an interactive intelligent tutoring system (PhysicsSim) that makes use of kinematics to help students understand the nuances of motion types and their graphical representations. A secondary goal is to evaluate the efficacy of PhysicsSim in teaching the students by evaluating their learning. The proposed system allows for personalized learning experience in an environment that combines video tutorials and interactive animations with guided exercises and problems to practice the skills. Effectiveness of the PhysicsSim will be tested in Introductory Physics classes in Spring 2020. The results will enable us to enhance the system to provide maximum support and optimal learning for students

Using Data Mining to Explore Why Community College Transfer Students Earn Bachelor’s Degrees With Excess Credits

Community college transfer students encounter challenges progressing toward a bachelor’s degree, leading to widespread transfer credit loss. This in turn may lower students’ chances of credential completion and increase the time and costs for students, their families, and taxpayers. This study reviews review three definitions of credit transfer inefficiency—credit transferability, credit applicability, and excess credits among completers—focusing on the last to examine why community college transfer students often end up with excess credits that do not count toward a bachelor’s degree. The authors use student transcript data from two state systems to examine the course-taking behaviors of community college transfer students who earn bachelor’s degrees with numerous excess credits and with few excess credits. Data-mining techniques enable them to examine a large number of variables that could explain the variation in students’ excess credits at graduation, including not only student demographics but also the types and timing of courses taken. Overall, more excess credits are associated with several factors, including taking larger proportions of 100- and 200-level courses and smaller proportions of 300-level courses throughout students’ progression toward completion, and taking 100-level courses in any subject—and specifically in math—immediately after transferring to a four-year institution. Findings suggest that institutions could help reduce credit transfer inefficiency by encouraging students to explore and choose a bachelor’s degree major early on so they can take the required lower division (100- and 200-level) courses at the community college and take mostly upper division 300- and 400-level courses in their desired major field once they transfer to a four-year institution

New Evidence of Success for Community College Remedial English Students: Tracking the Outcomes of Students in the Accelerated Learning Program (ALP)

This paper presents the findings from a follow-up quantitative analysis of the Community College of Baltimore County’s Accelerated Learning Program (ALP). Our results suggest that among students who enroll in the highest level developmental writing course, participation in ALP is associated with substantially better outcomes in terms of English 101 completion and English 102 completion (college-level English courses), which corroborates the results of a similar analysis completed in 2010. These results were consistent, and in some cases, even stronger, when we used propensity score matching. Moreover, using a larger number of cohorts and tracking students over a longer period of time, we also found that ALP students were more likely to persist to the next year than non-ALP students. Specific subgroup analyses for earlier versus later cohorts, as well as for Black and low-income students, revealed relationships between ALP participation and student outcomes that were similar to those found in the larger sample, although ALP appeared to be more effective for White and high-income students on some outcomes. Finally, we compared college-ready students enrolled in ALP sections of English 101 with their counterparts in wholly college-ready sections, and found that those in ALP sections had equivalent performance within English 101 itself, but slightly lower subsequent college-level course enrollment and completion

Pilot Source Study 2015: An Analysis of FAR Part 121 Pilots Hired after Public Law 111-216—Their Backgrounds and Subsequent Successes in US Regional Airline Training and Operating Experience

This report is the second in a series entitled Pilot Source Study 2015. Public Law 111-216 (Airline Safety and Federal Aviation Administration Extension Act of 2010) and the subsequent FAA regulation changed pilot hiring for US air carriers operating under 14 CFR Part 121. The Pilot Source Study 2015 was designed to determine the effect of Public Law 111-216 on US regional airlines after its effective date, August 1, 2013. The study collected records for 6,734 FAR Part 121 regional airline pilots to determine the effect of pilots’ backgrounds on their performance in regional airline training and operations. A previous report (Bjerke et al., 2016) compared the backgrounds of these pilots (post-law pilots) to the backgrounds of pilots hired between 2005 and 2011 (pre-law pilots). This report examines the performance of post-law new-hire pilots in initial training and operations as first officers for Part 121 regional air carriers. Post-law pilot backgrounds were measured against four performance measures: non-completions, extra training, extra initial operating experience (IOE), and extra recurrent training. Pilots who had the fewest non-completions and required less extra training were the recent college graduates (fewer than 4 years since graduation), pilots with fewer total flight hours (1,500 hours or less), and pilots who graduated from flight programs accredited by the Aviation Accreditation Board International (AABI). Pilots who required less extra IOE and less extra recurrent training were pilots whose previous employment was with a Part 121 air carrier, recent college graduates (fewer than 4 years since graduation), and pilots with fewer total flight hours (1,500 hours or less). Other background indicators of successful performance included the Institutional-Authority Restricted ATP (R-ATP); a bachelor’s degree, particularly in aviation; and prior military pilot experience. The third report of this series will compare background and success factors between pre-law pilots and post-law pilots

Pilot Source Study 2015: US Regional Airline Pilot Hiring Background Characteristic Changes Consequent to Public Law 111-216 and the FAA First Officer Qualifications Rule

This report is the first article in a series called Pilot Source Study 2015. Public Law (PL) 111-216, passed by the US Congress in 2010, and the subsequent FAA Regulation, Pilot Certification and Qualification Requirements for Air Carrier Operations Rule, abruptly changed the pilot hiring situation for US air carriers operating under 14 CFR Part 121. PL 111-216 became effective on August 1, 2013; thereafter, pilots were not eligible to be first officers in Part 121 air carriers unless they were certificated as Air Transport Pilots (ATP) with 1,500 hours of flight time, with some flight hour reductions for specified military and academic experiences. Recognizing that the rule had a notable impact on US regional airlines, the researchers visited 19 Part 121 regional airlines to extract data from their documents and records. De-identified background and corresponding performance data were recorded for 6,734 pilots hired after August 1, 2013. These data were analyzed in three articles, exploring the background characteristics of these pilots and determining to what extent there were differences in these background characteristics between post-law pilots (hired after August 1, 2013) and pre-law pilots (hired from 2005 to 2011). Besides the mandated increase in total flight hours and the requirement for an ATP certificate, the post-law pilots had less aviation-related academic experience, a lower proportion of flight instructors with more instructor experience, a larger proportion of military pilots, and a large range of flight experience suggesting career switching or returning to aviation. Among pilots with less experience, there was a significant reduction in multiengine time. This report is a preliminary article on the shift of pilot background characteristics as a result of the pilot certification and qualifications requirements mandated by Congress. Two future articles are being prepared. One article will analyze the success of post-law pilots in initial training for Part 121 operations, and another article will compare background and success factors between pilots hired before PL 111-216 and those hired after the law was passed

Release of dissolved organic carbon from seagrass wrack and its implications for trophic connectivity

ABSTRACT: The export of old leaves and stems (wrack) from seagrass meadows provides a mechanism for trophic connectivity among coastal ecosystems. As little of this wrack is consumed by mesograzers, leached dissolved organic carbon (DOC) may determine the importance of wrack as a trophic subsidy. However, few studies have examined the effect of seagrass type or age on the release of DOC or its bioavailability. We examined the amount and composition of DOC released from different wrack: Posidonia sinuosa, Amphibolis antarctica and the alga Laurencia sp. We then examined the effect of age on DOC leaching from P. sinuosa wrack. The bioavailability of the DOC was also assessed using a bacterial bioassay. The rate of DOC leaching from P. sinuosa leaves decreased exponentially with time. According to that exponential model, ~50% of the total DOC release occurred in the first 14 d and it would require a further 2.94 yr to release the same amount again. Fresh algae Laurencia sp. leached the greatest amount of DOC in the first 16 h (6.7 g kg-1 fresh weight (FW) wrack), followed by fresh P. sinuosa leaves (1.7 g kg-1 FW), A. antarctica leaves (1.1 g kg-1) and stems (0.6 g kg-1), 4 wk old P. sinuosa (67 g kg-1) and fine detritus (74 g kg-1). In all cases, the composition of the DOC was similar and dominated by the hydrophilic component (in P. sinuosa, predominantly sugars and amino acids). Leachates from all fresh wrack supported bacterial growth over 24 h. Leachate from older wrack either failed to support bacterial growth or only supported it for a limited time. Given the exponential decay in DOC release rate, the interacting timescales of transport and leaching will affect the value of wrack as a vector for trophic subsidies

Concentrations of Polychlorinated Biphenyls (PCB’s), Chlorinated Pesticides, and Heavy Metals and Other Elements in Tissues of Belugas, Delphinapterus leucas, from Cook Inlet

Tissues from Cook Inlet beluga whales, Delphinapterus leucas, that were collected as part of the Alaska Marine Mammal Tissue Archival Project were analyzed for polychlorinated biphenyls (PCB’s), chlorinated pesticides, and heavy metals and other elements. Concentrations of total PCB’s (ΣPCB’s), total DDT (ΣDDT), chlordane compounds, hexachlorobenzene (HCB), dieldrin, mirex, toxaphene, and hexachlorocyclohexane (HCH) measured in Cook Inlet beluga blubber were compared with those reported for belugas from two Arctic Alaska locations (Point Hope and Point Lay), Greenland, Arctic Canada, and the highly contaminated stock from the St. Lawrence estuary in eastern Canada. The Arctic and Cook Inlet belugas had much lower concentrations (ΣPCB’s and ΣDDT were an order of magnitude lower) than those found in animals from the St. Lawrence estuary. The Cook Inlet belugas had the lowest concentrations of all (ΣPCB’s aver-aged 1.49 ± 0.70 and 0.79 ± 0.56 mg/kg wet mass, and ΣDDT averaged 1.35 ± 0.73 and 0.59 ± 0.45 mg/kg in males and females, respectively). Concentrations in the blubber of the Cook Inlet males were significantly lower than those found in the males of the Arctic Alaska belugas (ΣPCB’s and ΣDDT were about half). The lower levels in the Cook Inlet animals might be due to differences in contaminant sources, food web differences, or different age distributions among the animals sampled. Cook Inlet males had higher mean and median concentrations than did females, a result attributable to the transfer of these compounds from mother to calf during pregnancy and during lactation. Liver concentrations of cadmium and mercury were lower in the Cook Inlet belugas (most cadmium values were <1 mg/kg and mercury values were 0.704–11.42 mg/kg wet mass), but copper levels were significantly higher in the Cook Inlet animals (3.97–123.8 mg/kg wet mass) than in Arctic Alaska animals and similar to those reported for belugas from Hudson Bay. Although total mercury levels were the lowest in the Cook Inlet population, methylmercury concentrations were similar among all three groups of the Alaska animals examined (0.34–2.11 mg/kg wet mass). As has been reported for the Point Hope and Point Lay belugas, hepatic concentrations of silver were r