3,295 research outputs found
Three-Body Capture of Irregular Satellites: Application to Jupiter
We investigate a new theory of the origin of the irregular satellites of the
giant planets: capture of one member of a ~100-km binary asteroid after tidal
disruption. The energy loss from disruption is sufficient for capture, but it
cannot deliver the bodies directly to the observed orbits of the irregular
satellites. Instead, the long-lived capture orbits subsequently evolve inward
due to interactions with a tenuous circumplanetary gas disk.
We focus on the capture by Jupiter, which, due to its large mass, provides
the most stringent test of our model. We investigate the possible fates of
disrupted bodies, the differences between prograde and retrograde captures, and
the effects of Callisto on captured objects. We make an impulse approximation
and discuss how it allows us to generalize capture results from equal-mass
binaries to binaries with arbitrary mass ratios.
We find that at Jupiter, binaries offer an increase of a factor of ~10 in the
capture rate of 100-km objects as compared to single bodies, for objects
separated by tens of radii that approach the planet on relatively low-energy
trajectories. These bodies are at risk of collision with Callisto, but may be
preserved by gas drag if their pericenters are raised quickly enough. We
conclude that our mechanism is as capable of producing large irregular
satellites as previous suggestions, and it avoids several problems faced by
alternative models.Comment: 39 pages, 12 figures, 1 table, submitted to Icaru
The Harkive Project: Popular Music, Data & Digital Technologies
This thesis is about research around Harkive, an online project designed by this researcher, which gathers stories, reflections, and other data from people about their everyday engagement with popular music. Since 2013, over 1,000 people have contributed to the project, producing around 8,000 texts and highlighting the music reception activities of contemporary music listeners. The thesis presents an analysis of the texts and other data generated, answering a key research question: What can an analysis of the data generated by The Harkive Project reveal about the music reception practices of respondents? To answer this question, the researcher developed an experimental, innovative approach that conceives of Harkive as a space in which people can reflect upon their engagement with music, whilst simultaneously acting as a place that is able to replicate many of the commercial practices related to data collection and processing that have recently emerged as influential factors in the ways that popular music is produced, distributed and consumed. By focusing on a set of findings about the way people reflect on their engagement with music within the Harkive space, this thesis engages practically and critically with these new conditions. Simultaneously, the research explores how the systems of data collection and analysis that facilitate this are technologically complex, subject to rapid change, and often hidden behind commercial and legal firewalls, making the study of them particularly difficult. This then enables us to explore how the use of digital, data and Internet technologies by many people during the course of their everyday lives is providing scholars with new opportunities and methods for undertaking research in the humanities, and how this in turn is leading to questions about the role of the researcher in popular music studies, and how the discipline may take into account the new technologies and practices that have so changed the field. Ultimately, the thesis makes the argument that a greater practical understanding and critical engagement with digital, data and Internet technologies is essential, both for music consumers and popular music scholars, and demonstrates how this work represents a significant contribution to this task
Language in Las Vegas: ESL training programs in Las Vegas casino hotels
The study was focused on ESL training for employees within the Casino hotel industry in Las Vegas, Nevada. The overall purpose of the study was to explore the degree to which ESL training programs were being implemented within and/or in use by the casino hotel industry in Las Vegas. While the a review of the literature had suggested that ESL efforts were being employed by the industry, little was known as to overall parameters of the efforts being undertaken with respect to the size, content, and modes of delivery. Therefore, the research questions underlying the study were as follows: (1) What is the nature and current use of ESL training programs within casino hotels in Las Vegas? (2) What, if any, is the relationship between ESL training programs and hotel size?;The findings of the study suggest that ESL training is being provided for most industry employees in the larger casinos with the level of educational support dropping as the as the size of the facility decreases to a level of no support in the smallest ones
Run sprint interval training induces fat loss in women
Repeated high intensity, short duration exercise, (sprint interval training, SIT) has been shown to be a time efficient strategy to induce aerobic and anaerobic adaptations in both men and women. Body composition changes have been shown in men but the effects in women are unclear. This study assessed body composition, waist circumference (WC) VC\u3e2max, rating of perceived exertion (RPE), anaerobic peak power, and the blood lipid profile after SIT. Fifteen female participants trained 3x/wk for 6 weeks: 30 sec all-out sprints (manually driven treadmill), 4-6 bouts/session, 4 min recovery/bout vs. control (n=9). The control group did not adhere to the control protocol with several undertaking training and/or weight loss programs during the duration of the study and thus analysis was reserved to the training group. Significant improvements (p\u3c0.05) occurred for body fat %, fat mass, WC, VC^max, and anaerobic power within the training group. Body fat %, fat mass and waist circumference decreased by 6.9 % (24.7 ± 4.9 to 23.0 ± 4.6%), 7.9% (15.1 ± 3.6 to 13.9 ± 3.4 kg) and 3.5% (80.1 ± 4.2 to 77.3 ± 4.4 cm) respectively. VC^max increased 9.6% (46.0 ±4.6 to 50.4 ±5.5 ml-kg\u271min\u271). Anaerobic peak power, increased by 3.8% (0.64kph). Three day food records were analyzed for energy (kJ), CHO (g), PRO (g) and FAT (g) intake with no difference pre/post training (p\u3c0.05). No significant changes in body mass, RPE or the blood lipid profile: TC (p=0.684), HDL (p=0.398), LDL (p=0.494), TG (p=0.087), and TC:HDL (p=0.733). SIT resulted in similar aerobic and anaerobic adaptations as in men and positive but substantially less body fat losses than observed in men in our lab. SIT may be a time efficient strategy to help combat the rising obesity epidemic and ameliorate health of both men and women
Effectiveness of computer/video assisted instruction for adults in a nonformal setting: a preliminary study
The purpose of this study was to determine if nonformal adult students learn at a different level when taught by computer/video assisted instruction when compared to a conventional approach such as lecture with questions and overhead projections;Interactive lessons on agricultural futures hedging and agricultural futures options were written by the investigator and computer/video assisted futures options lessons presented to the treatment groups at Wayne, Enid, and Cherokee, Oklahoma;Three groups of nonformal adult students (N = 60) were selected to participate in the experiment. Pre-tests were developed and administered to a randomized one-half of both the treatment and control groups. The Randomized Solomon Four-Group Design was used to overcome problems of external validity. The four groups included: (1) no pre-test/no treatment, (2) pre-test/no treatment, (3) no pre-test/treatment, and (4) pre-test/treatment;The pre-test mean score for all participants was 18.31 out of a possible 30. The post-test mean score for all participants was observed to be 20.58. Comparisons of pre-test and post-test group means revealed that the post-test mean score for both the control and experimental groups was higher than the pre-test group means. Group pre-test mean scores were observed to be significantly different; however, these differences did not carry over to the post-test mean scores or the differences between pre- and post-test mean scores for each group;Regression analysis of variables using post-test mean as the dependent variable revealed that pre-test score, educational level, sex, high school agricultural instruction, and location accounted for the majority of variance among group means. Analysis of covariance tests selecting the above variables as covariates did not provide significant differences between the treatment and control group mean scores;Significant differences were observed between experimental and control group pre- and post-test mean scores when grouped according to educational background of the participants
Craig Hamilton in a Faculty Recital
This is the program for the faculty recital featuring trumpet player Craig Hamilton. Pianist Rebecca Moore and organist Russell Hodges accompanied the performance. This recital took place on September 10, 2002, in the W. Francis McBeth Recital Hall
Hydrogeological characterization of the Mabou Group in the Picadilly region, New Brunswick
The Mabou Group in the Picadilly region of New Brunswick consists predominantly of red siltstones with interbeds of sandstone and conglomerate. The Mabou is of importance in this region as it overlies evaporite deposits of economic value. Given that the Mabou is several hundred meters thick, yet possesses no significant marker beds, it has remained stratigraphically undifferentiated in the Picadilly region over the course of previous regional mapping efforts in the area. Given the lack of a stratigraphic framework, coupled with insufficient hydrogeological sampling and test data to delineate any laterally extensive flow zones, the hydro-stratigraphy of this sedimentary package has not been established.
Based on experience gained at other operations, Potash Corporation of Saskatchewan Inc. (PCS) recognized the need to take a proactive approach towards understanding the hydrogeology of the Picadilly mine development site. PCS has used a specialized technique in characterizing boreholes to measure depth-profiles of hydrophysical properties by logging the electrical conductivity of the borehole fluids over a period of time. Through the interpretation of these logging results, with the context provided by conventional geophysical logging data and nearby exploration drill core, this research seeks to identify zones of flow and assess whether or not any major units with lateral connectivity can be identified.
The results highlight four zones of interest within the Mabou: the Upper Mabou; vuggy porosity directly above gypsum-infilled fractures; vugs and fractures within the Medium Sandstone subdivision; and the lower Mabou Siltstone at the base of the Mabou Group (within ~15m of base). Three of these zones are of interest as they tend to have relatively high permeabilities, with permeabilities over 10 000 md measured within the Upper Mabou, as high as 1800 md in the vuggy porosity zone directly above gypsum-filled fractures and as high as 1900 md within the Medium Sandstone subdivision . The fourth zone, found at the base of the Mabou Group, is of interest because the modest to low permeability recorded (as high as 38 md) is higher than the surrounding rocks and is in close proximity to the caprock of future mining activity.
The permeabilities of the rocks studied in this research are believed to be dominantly controlled by secondary porosity. In the case of the permeable zone identified above the zone of gypsum-infilled fractures, relatively high porosities (9 to 15%) were interpreted from geophysical logs. These elevated porosities are due to the presence of vuggy porosity in this zone. However, no clear correlation between log-derived porosity and permeability was observed for the other permeable zones. This is believed to be due to the fact that fractures were the dominant control on porosity in these zones, and that the incremental contribution of fracture porosity to total porosity was too small to be readily identified
Quantum walk with a four-dimensional coin
We examine the physical implementation of a discrete time quantum walk with a four-dimensional coin. Our quantum walker is a photon moving repeatedly through a time delay loop, with time being our position space. The quantum coin is implemented using the internal states of the photon: the polarization and two of the orbital angular momentum states. We demonstrate how to implement this physically and what components would be needed. We then illustrate some of the results that could be obtained by performing the experiment
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