A Study on Conical Rocket Stabilization

The objective was to develop a finless model rocket . The idea evolved after seeing the Army\u27s Sprint anti-ballistic missile, which is conical in shape and does not have fins for primary aerodynamic stabilization . In designing the model rocket, a scale drawing was made, and center of gravity (CG) and center of pressure (CP) computations transferred to it. The initial design proved unstable because the CG and CP were too close together. Another drawing was made with the addition of a payload section to carry necessary weight to allow moving the CG forward. This second design was mathematically stable. For stability testing, a string was attached to the rocket\u27s CG and spun in a circular path. Stability was achieved when all counterclockwise torques equaled all clockwise torques (not measured). An engine was selected by weight-carrying ability. The rocket was flown using conventional techniques, and flight characteristics were collected. Movies were made for further reference, and the rocket proved stable

Population Dynamics and Angler Exploitation of the Unique Muskellunge Population in Shoepack Lake, Voyageurs National Park, Minnesota

A unique population of muskellunge Esox masquinongy inhabits Shoepack Lake in Voyageurs National Park, Minnesota. Little is known about its status, dynamics, and angler exploitation, and there is concern for the long-term viability of this population. We used intensive sampling and mark–recapture methods to quantify abundance, survival, growth, condition, age at maturity and fecundity and angler surveys to quantify angler pressure, catch rates, and exploitation. During our study, heavy rain washed out a dam constructed by beavers Castor canadensis which regulates the water level at the lake outlet, resulting in a nearly 50% reduction in surface area. We estimated a population size of 1,120 adult fish at the beginning of the study. No immediate reduction in population size was detected in response to the loss of lake area, although there was a gradual, but significant, decline in population size over the 2-year study. Adults grew less than 50 mm per year, and relative weight (W r) averaged roughly 80. Anglers were successful in catching, on average, two fish during a full day of angling, but harvest was negligible. Shoepack Lake muskellunge exhibit much slower growth rates and lower condition, but much higher densities and angler catch per unit effort (CPUE), than other muskellunge populations. The unique nature, limited distribution, and location of this population in a national park require special consideration for management. The results of this study provide the basis for assessing the long-term viability of the Shoepack Lake muskellunge population through simulations of long-term population dynamics and genetically effective population size

The 2.5 m Telescope of the Sloan Digital Sky Survey

We describe the design, construction, and performance of the Sloan Digital Sky Survey Telescope located at Apache Point Observatory. The telescope is a modified two-corrector Ritchey-Chretien design which has a 2.5-m, f/2.25 primary, a 1.08-m secondary, a Gascoigne astigmatism corrector, and one of a pair of interchangeable highly aspheric correctors near the focal focal plane, one for imaging and the other for spectroscopy. The final focal ratio is f/5. The telescope is instrumented by a wide-area, multiband CCD camera and a pair of fiber-fed double spectrographs. Novel features of the telescope include: (1) A 3 degree diameter (0.65 m) focal plane that has excellent image quality and small geometrical distortions over a wide wavelength range (3000 to 10,600 Angstroms) in the imaging mode, and good image quality combined with very small lateral and longitudinal color errors in the spectroscopic mode. The unusual requirement of very low distortion is set by the demands of time-delay-and-integrate (TDI) imaging; (2) Very high precision motion to support open loop TDI observations; and (3) A unique wind baffle/enclosure construction to maximize image quality and minimize construction costs. The telescope had first light in May 1998 and began regular survey operations in 2000.Comment: 87 pages, 27 figures. AJ (in press, April 2006

The Sloan Digital Sky Survey: Technical Summary

The Sloan Digital Sky Survey (SDSS) will provide the data to support detailed investigations of the distribution of luminous and non- luminous matter in the Universe: a photometrically and astrometrically calibrated digital imaging survey of pi steradians above about Galactic latitude 30 degrees in five broad optical bands to a depth of g' about 23 magnitudes, and a spectroscopic survey of the approximately one million brightest galaxies and 10^5 brightest quasars found in the photometric object catalog produced by the imaging survey. This paper summarizes the observational parameters and data products of the SDSS, and serves as an introduction to extensive technical on-line documentation.Comment: 9 pages, 7 figures, AAS Latex. To appear in AJ, Sept 200

Patient perspectives on considerations, tradeoffs, and experiences with multiple myeloma treatment selection: a qualitative descriptive study

Abstract Background Advances in multiple myeloma treatment and a proliferation of treatment options have resulted in improved survival rates and periods of symptom-free remission for many multiple myeloma patients. As a result, health-related quality of life (HRQoL) concerns related to myeloma treatments have become increasingly salient for this patient population and represent an important consideration guiding patients’ treatment choices. To gain an understanding of patients’ experiences with choosing myeloma therapies and explore the HRQoL concerns that are most important to them, we interviewed a diverse sample of US-based multiple myeloma patients about their treatment considerations. Methods We conducted a qualitative descriptive study using in-depth interviews. Participants reflected on (1) the factors that were most important to them when thinking about multiple myeloma treatment and how these have changed over time, (2) how they might weigh the importance of treatment efficacy vs. side effects, (3) trade-offs they would be willing to make regarding efficacy vs. HRQoL, and (4) treatment changes they had experienced. Interviews were audio-recorded and transcribed, and narratives were analyzed using applied thematic analysis. Results We interviewed 21 patients, heterogeneous in their disease trajectory and treatment experience. Participants were 36 to 78 years, 52% female, and 38% Black. Efficacy was named as the most important treatment consideration by almost two-thirds of participants, and over half also valued HRQoL aspects such as the ability to maintain daily functioning and enjoyment of life. Participants expressed concern about potential treatment side effects and preferred more convenient treatment options. Although participants stated largely trusting their clinicians’ treatment recommendations, many said they would stop a clinician-recommended treatment if it negatively impacted their HRQoL. Participants also said that while they prioritized treatment efficacy, they would be willing to change to a less efficacious treatment if side effects became intolerable. Conclusions Our findings link to other reports reflecting considerations that are important to multiple myeloma patients, including the importance placed on increasing life expectancy and progression-free survival, but also the tension between treatment efficacy and quality of life. Our results extend these findings to a racially diverse US-based patient population at different stages in the disease trajectory