Anatomy of an Asteroid Break-Up: The Case of P/2013 R3

We present an analysis of new and published data on P/2013 R3, the first asteroid detected while disintegrating. Thirteen discrete components are measured in the interval between UT 2013 October 01 and 2014 February 13. We determine a mean, pair-wise velocity dispersion amongst these components of $\Delta v = 0.33\pm0.03$ m s$^{-1}$ and find that their separation times are staggered over an interval of $\sim$5 months. Dust enveloping the system has, in the first observations, a cross-section $\sim$30 km$^2$ but fades monotonically at a rate consistent with the action of radiation pressure sweeping. The individual components exhibit comet-like morphologies and also fade except where secondary fragmentation is accompanied by the release of additional dust. We find only upper limits to the radii of any embedded solid nuclei, typically $\sim$100 to 200 m (geometric albedo 0.05 assumed). Combined, the components of P/2013 R3 would form a single spherical body with radius $\lesssim$400 m, which is our best estimate of the size of the precursor object. The observations are consistent with rotational disruption of a weak (cohesive strength $\sim$50 to 100 N m$^{-2}$) parent body, $\sim$400 m in radius. Estimated radiation (YORP) spin-up times of this parent are $\lesssim$1 Myr, shorter than the collisional lifetime. If present, water ice sublimating at as little as 10$^{-3}$ kg s$^{-1}$ could generate a torque on the parent body rivaling the YORP torque. Under conservative assumptions about the frequency of similar disruptions, the inferred asteroid debris production rate is $\gtrsim$10$^3$ kg s$^{-1}$, which is at least 4% of the rate needed to maintain the Zodiacal Cloud.Comment: 44 pages, 13 figures, accepted by Astronomical Journa

Weed Control in Windbreaks.

2 p

A-2000: Close air support aircraft design team

The US Air Force is currently faced with the problem of providing adequate close air support for ground forces. Air response to troops engaged in combat must be rapid and devastating due to the highly fluid battle lines of the future. The A-2000 is the result of a study to design an aircraft to deliver massive fire power accurately. The low cost A-2000 incorporates: large weapons payload; excellent maneuverability; all weather and terrain following capacity; redundant systems; and high survivability

Profitable Grain Sorghum Production in the Rolling Plains.

8 p

THE EFFECT OF CONCUSSION ON REACTION TIME AND DUAL TASKING ABILITY IN A SIMULATED DRIVING ENVIRONMENT

The purpose of this study was to determine the effect of concussion on drivers’ reaction time and dual tasking ability in a simulated driving environment. Testing was performed with a STISIM Model 400 driving simulator. Participants (10 healthy and 10 two weeks to three months post-concussion) were exposed to multiple reaction time scenarios including pedestrian, vehicle, and cyclist incursions. Dual tasking ability was measured using STISIM dual task scenarios. There were longer reaction times in concussed participants (F(1, 18) = 2.072, p = .001, ��2=.600) and a lower number of mean dual task passes in concussed participants (F(1, 18) = 23.145, p = .001, ��2 = .563), both of which were statistically significant. Understanding the effect concussion has on driving ability is the first step to creating a guideline for clinicians to refer to when assessing concussed patients and determining if they are fit to drive

Implementing the Five-A Model of technical refinement: Key roles of the sport psychologist

There is increasing evidence for the significant contribution provided by sport psychologists within applied coaching environments. However, this rarely considers their skills/knowledge being applied when refining athletes’ already learned and well-established motor skills. Therefore, this paper focuses on how a sport psychologist might assist a coach and athlete to implement long-term permanent and pressure proof refinements. It highlights key contributions at each stage of the Five-A Model—designed to deliver these important outcomes—providing both psychomotor and psychosocial input to the support delivery. By employing these recommendations, sport psychologists can make multiple positive contributions to completion of this challenging task

The Ursinus Weekly, March 11, 1971

ProTheatre schedules 9 Spring productions • Student Life Committee suggests twelve semester open houses; President Pettit approves half • Union pilot committee seeks new members • Seniors plan \u2771 Showboat • Gymnasium site excavated • Pi Nu sponsors annual Songfest • Festival of the Arts • Blood drive • Editorial: Where do we go from here? • Focus: Tom Mack • Movie critic: What\u27s at the movies (and worth seeing) • Letters to the editor: Freaks out; Sterling studies; Excellent issue; G.P. knocks U.S.G.A. • Hamlet • Robin and the other hoods • Inside track • Hoopmen complete season • Snellbelles protest lack of floortime • Sports cornerhttps://digitalcommons.ursinus.edu/weekly/1140/thumbnail.jp

Profitable Grain Sorghum Production in the Rolling Plains.

8 p

Take a walk on the wild side: Exploring, identifying, and developing consultancy expertise with elite performance team leaders

Objectives: Stemming from sport psychology’s recent shift to examine the effective management of elite sports team organizations, the extensive, significant, and complex challenges faced by those with responsibility for team performance have been emphasized. Recognizing that most work in this budding area has been theoretical in nature, our contribution to this special issue consequently identifies and critically evaluates some implications for excellence in practitioners who support leaders of elite sport performance teams. Method: Narrative review and commentary. Results and Conclusions: To survive and succeed, leaders of elite teams must: (a) negotiate complex and contested socio-political dynamics both within and outside their performance department; (b) make impactful and consistent real-time decisions; and (c) continually reinforce and protect their programme. To provide an optimally impactful and valued service, sport psychologists must therefore be able to advise on a broad and politically-astute leadership style and, most critically for consultancy excellence: (a) work within a professional judgment and decision making model; (b) facilitate the leader’s adaptive expertise and nested decision making; and (c) operate a proactive, forthright, and straight approach to ethical considerations. Based on these implications, we conclude by providing suggestions for the training and development of applied consultants

The Ursinus Weekly, May 20, 1971

U.C. Century II fund drive commences; Goal for \u2770-\u2775 set at 5.5 million • Samuel L. Gandy speaks June 6th • Pancoast takes sabbatical leave • Ursinus gives merit scholarships • Women\u27s curfews change; Weekend hours abolished • What has become of APEs? • Editorial: Apathy kills • Focus: Selby Nera • U.S.G.A. wrap-up 1970-71: A year in pursuit of progress • Appearance & reality? • Double standard is alive and living in Collegeville • Movie critic: Little big man • Student Union and Bomberger renovation to begin soon • Faculty portrait: Dr. Ray Schultz • U.C. English comprehensive to present times-one view • U.C. President William Pettit reflects on past year, his first as President • Mrs. Watson has perfected the art of winning • After four years • Varsity golf: Linksmen finish 6-8 • D. Larson pitches 3 hitter • Final examination schedulehttps://digitalcommons.ursinus.edu/weekly/1147/thumbnail.jp