The Distribution of X-Ray Induced Crossovers from Curly Inversion Heterozygotes of Drosophila melanogaster Females

That crossing may occur in oogonial cells was suggested by the results of experiments by Whittinghill [1] in which crossing over was induced by x-rays in the X-chromosomes of Drosophila females homozygous for the c3G asynaptic factor. It had previously been demonstrated that induced crossovers recovered from Drosophila males were of spermatogonial origin [2,3]. Cooper's observations [4] of chiasmata in gonial cells of both sexes of Drosophila may provide cytological foundations for the hypothesis of gonial origin of some crossovers, particularly those which are x-ray induced. Somatic crossing over, the basis for the occurranece of twin spots in the hypodermis of Drosophilamales and females [5], closely parallels gonial crossing over in the formation of daughter cells which have become homozygous distally. The possible consequences of oogonial crossing over upon linking data, as recently discussed by Whittinghill [6], illustrate the need for further investigation of this phenomena. This paper reports the results of x-ray induced crossing over in Curly inversion heterozygotes of Drosophila melanogaster females, and these results are interpreted in relation to normal, or random, meiotic events as opposed to oogonial events of recombination

Introductory Graphics Programming: Transition to IMPACT

Computer programming is a difficult field for students to learn, while the most effective teaching strategies are not known conclusively. Educator’s opinions vary as to the optimal approach. It is largely a point of agreement however that programming, as an applied field, is learned more quickly as a function of practice. Traditional lecture approaches impose a passive mindset upon the student and uses valuable time. This study posits that students might be better served by minimizing student time passively listening to lectures and instead keeping students actively engaged at the keyboard work through programming problems individually and in small groups. The IMPACT model helps facilitate this move away from a purely instructor-led model to a more student-centered model. Both affective and performance metrics are gathered and analyzed in the transition to the new teaching model. As the first IMPACT class, run in a true IMPACT room, is currently in session, study results are pending

Yields of relay cropped greens grown in green roof production systems

As interest in urban food production increases, urban farmers are looking for solutions to the challenge of space availability. One solution is to move production to building rooftops, a space that is often underutilized. The use of green roof technology is one method of achieving food production on rooftops; however, there are some additional challenges associated with this practice as a result of the fast-draining, low-nutrient media used. This is particularly challenging for vegetable crops, which typically require more nutrients than the ornamental plants traditionally grown in green roof media. Some rooftop farmers are adding additional organic matter in the form of compost to their beds as an alternative to chemical fertilizers. Currently, there is little research on how rooftop production systems affect crops. Green roof platforms were established at the Harold R. Benson Research and Demonstration Farm in Frankfort, Kentucky, to examine crop yield in green roof systems supplemented with compost. Treatments were a topsoil no compost control, a green roof media no compost control and 3 green roof media treatments: the addition of 0.33, 0.66, or 1 kg m-2 of compost. Organic fertilizers were used to supply additional nutrients to vegetable plants. The crops selected were lettuce, arugula, mizuna, mustard, Swiss chard, kale, and spinach. These were relay cropped in succession during two growing seasons (2018 and 2019). At each harvest, the amount of time harvesting required (in seconds), total yield, and marketable yield (determined by visual examination) were measured for each platform. Yield results were analyzed in R. Analysis of variance was performed on all variables for each crop; compost treatment and year were fixed effects. Significant differences between treatment means were analyzed using Tukey HSD (alpha of 0.05). Results for kale show differences between 2018 and 2019 for harvest time and total yield in the topsoil control, but no differences for marketable yield. These differences are likely due to weather conditions. Kale harvest time, total yield in 2019 but not 2018, and marketable yield were highest in the topsoil control. Harvest time of the topsoil control was not significantly higher than the 1 kg m-2 of compost in green roof media. The marketable yield of the topsoil control was not significantly higher than 0.66 or 1 kg m-2 compost treatments in green roof media. Results for additional crops will also be presented

Work In Progress: Combining Concept Inventories with Rapid Feedback to Enhance Learning

In this project our goal is to adapt the Concept Inventory for frequent classroom use, and to implement it in a system to provide rapid feedback to students of their understanding of key concepts being presented. The feedback system acts as the focal point and catalyst to encourage students, working in pairs, to assist each other in correcting misconceptions or deepening each other’s understanding of the topic at hand. Furthermore, the system allows the professor to assess the students’ level of comprehension (or misconception) in a just-in-time fashion, and thus guides his or her pacing and coverage of the material. The rapid feedback is enabled through wireless-networked handheld computers. In this first year of the study, we have implemented the system in a lower-level, core-engineering course (engineering mechanics: statics). This paper will focus on the motivation for and the design of this project; our presentation will describe results from the first implementation

Don’t Stop the Music: An Exploration of First-Generation College Students’ Use of Music During Pre-Pandemic and Pandemic Times

First-generation college student enrollment has increased significantly in recent years and a sizeable canon exists to help understand their journey to and through higher education, as well as subsequent persistence, retention and graduation rates. This research is the first to investigate how and why first-generation college students use music. Two studies compare usage patterns in pre- and pandemic settings. Study One (N=583) found that students listen to roughly four hours per day and that nearly 75% of students listen to music while studying. Moreover, first-generation students indicated that they listen to music more frequently and for more inward-focused coping reasons. Study Two (N=441) was an Internet survey (conducted during the pandemic) that supported and augmented many of Study One’s findings. While music plays an important role for all students, it is critically important to first-generation students. Key findings illuminate what genres students listen to and eleven reasons why students listen to music, which are highlighted by identifying and expressing emotions, relieving stress, relieving stress, and increasing creativity

The Nature of Linkage Variation with Age in Inversion Heterozygotes of Drosophila melanogaster

Two kinds of variation in linkage values in Drosophila experiments are well known but poorly understood. One is the change in crossover values with increasing age of the female as shown by Bridges [1]; the other is excessive variation from female to female as pointed out by Gowen [2]. Studies reported in the present paper on an age effect in a special situation may contribute to the interpretation of both problems. They also serve as controls for the irradiation paper which follows [3]. The chief result of aging is a rapid decrease in recombination values during the first six days of egg-laying, particularly at or near the spindle attachment of the chromosome. After that period smaller changes consist, with variations, of a slight rise and second fall. In recognition of this Bridges [4] has defined as a condition for chromosome mapping the use of data from young females. From such data inferences are made as to the amount of actual crossing over which has occurred between genes which are assumed to be heterozygous at the time when the germ cells enter meiosis. That this procedure may overestimate the amount of crossing over has been elaborated by the senior author both by reasoning back from observable clustering of the data [5] and by deducing certain consequences of crossing over premeiotically, in gonial cells [6]. The present experiment shows an age effect and clustering attributable to oogonial crossing over in the same body of data, where meiotic crossovers have been greatly reduced or eliminated by inversions

Mars Ascent Vehicle Hybrid Propulsion Development

Hybrid propulsion is being investigated as a propulsion method for a possible Mars Ascent Vehicle (MAV) application. MAV is part of a proposed larger Mars Sample Return (MSR) campaign plan to bring samples from Mars to earth for examination. The Mars Ascent Vehicle would launch Mars surface samples found and packaged by the Mars 2020 mission to orbit around Mars. This version of hybrid propulsion is based on a wax based solid fuel, called SP7A, and a Mixed Oxides of Nitrogen oxidizer, MON-25. SP7 is a new fuel formulation developed by Space Propulsion Group and was modified for this application to be resistant to Mars temperature extremes and modified again to lower the regression rate to become SP7A. MON-25 was chosen for its low freezing temperature. Due to cost constraints, MON-3 was the oxidizer used during testing through 2018. In 2019, full scale hybrid testing with MON-25 commenced in Mojave, CA by Whittinghill Aerospace. One flight motor will be subjected to thermal cycling in a vacuum and later fired in a vacuum to demonstrate the proposed Liquid Injection Thrust Vector Control system performance at White Sands Test Facility (WSTF). In addition, there will be MON-25 characterization work done at Purdue University and WSTF. Additional testing of subscale and full scale motors will be conducted with MON-3 with fuel grain stress, fuel grain support and case design test objectives by Space Propulsion Group Inc. of Butte, MT. This paper documents some of the testing, issues and accomplishments with the MAV hybrid propulsion option that is being considered (along with a two-stage solid propulsion option)

Evaluating the Effects of Bacillus subtilis Treatment and Planting Depth on Saffron (Crocus sativus L.) Production in a Green Roof System

Given the current urbanization context and rising interest in green roof systems, growing a high-value crop such as saffron crocus in green roof medium could be an opportunity to use the benefits of both the crop and the green roof system; the drainage, aeration, and sand-like texture of green roof media make it suited for saffron production, and the saffron market price could make green roof production commercially viable. Various factors, including plant diseases and planting depth, could affect saffron production. Therefore, this research was conducted to evaluate the effects of planting depth and biofungicide treatments using Bacillus subtilis on saffron production in a green roof system. A completely randomized factorial block design was used with planting depth (10 cm and 15 cm) and B. subtilis strain QST 713 biofungicide treatments (an untreated control, 15.6 × 109 cfu/L, and 31.2 × 109 cfu/L) as independent variables. In 2019, fresh flower yield, fresh stigma yield, and dry stigma yield were calculated during harvesting, and additional data on flower number, tepal length and width, stigma length, and harvest time were collected in 2020. All variables were analyzed using analysis of variance (ANOVA) with planting depth and biofungicide treatments as fixed effects using R. Fresh stigma yield and dry stigma yield were higher in the 10-cm planting depth in 2019. Results were opposite in 2020: flower number, fresh flower yield, fresh stigma yield, dry stigma yield, and harvest time were higher in the 15-cm planting depth than the 10-cm planting depth. B. subtilis treatments did not affect any studied variable in 2020, but in 2019, the higher level of fungicide treatment resulted in lower fresh flower yield and dry stigma yield. There was no effect of biofungicide treatment and planting depth on tepal length, tepal width, and stigma length in both years. This study showed that growing saffron crocus on green roofs is feasible and even resulted in higher yield than field production in many saffron-producing regions and countries. In addition, results indicated that shallow planting might be suitable for annual production, whereas deeper planting could be ideal for perennial production based on the objective. Our findings demonstrated the feasibility of saffron production in the green roof system and suggest further research to develop best management practices

Privacy, Anonymity, and Big Data in the Social Sciences

Quality social science research and the privacy of human subjects require trust

The role of endogenous lipids in the emulsifying properties of cocoa

This paper describes a study in which the emulsifying properties of cocoa material with and without its lipid fraction were explored. This study was motivated by the commercial interest in naturally-occurring particulate emulsifiers as opposed to the chemically modified emulsifying particles presently available for commercial use. The hypothesis was that endogenous lipids from cocoa were responsible for driving the formation of stable oil-in-water (o/w) emulsions. The data presented includes relative quantification of phospholipids from different commercially available cocoa material using 31P NMR spectroscopy and analyses of the emulsifying power of delipidified cocoa material. The commercially available cocoa material comprised several phospholipids, with phosphatidylcholine being the most abundant in all samples. Dispersions of delipidified cocoa material were found to drive the formation of o/w emulsions despite the absence of lipids. We therefore concluded that the emulsifying behaviour of cocoa material is not entirely reliant upon the endogenous lipids. This suggests that cocoa material may have a new and potentially widespread use in industrial food preparation and may inform manufacturing strategies for novel food grade emulsifiers