Strange hyperon and antihyperon production from quark and string-rope matter

Hyperon and antihyperon production is investigated using two microscopical models: {\bf (1)} the fast hadronization of quark matter as given by the ALCOR model; {\bf (2)} string formation and fragmentation as in the HIJING/B model. We calculate the particle numbers and momentum distributions for Pb+Pb collisions at CERN SPS energies in order to compare the two models with each other and with the available experimental data. We show that these two theoretical approaches give similar yields for the hyperons, but strongly differ for antihyperons.Comment: 11 pages, Latex, 3 EPS figures, contribution to the Proceedings of the 4th International Conference on Strangeness in Quark Matter (SQM'98), Padova, Italy, 20-24 July 199

Stability ordering of cycle expansions

We propose that cycle expansions be ordered with respect to stability rather than orbit length for many chaotic systems, particularly those exhibiting crises. This is illustrated with the strong field Lorentz gas, where we obtain significant improvements over traditional approaches.Comment: Revtex, 5 incorporated figures, total size 200

Correspondence between geometrical and differential definitions of the sine and cosine functions and connection with kinematics

In classical physics, the familiar sine and cosine functions appear in two forms: (1) geometrical, in the treatment of vectors such as forces and velocities, and (2) differential, as solutions of oscillation and wave equations. These two forms correspond to two different definitions of trigonometric functions, one geometrical using right triangles and unit circles, and the other employing differential equations. Although the two definitions must be equivalent, this equivalence is not demonstrated in textbooks. In this manuscript, the equivalence between the geometrical and the differential definition is presented assuming no a priori knowledge of the properties of sine and cosine functions. We start with the usual length projections on the unit circle and use elementary geometry and elementary calculus to arrive to harmonic differential equations. This more general and abstract treatment not only reveals the equivalence of the two definitions but also provides an instructive perspective on circular and harmonic motion as studied in kinematics. This exercise can help develop an appreciation of abstract thinking in physics.Comment: 6 pages including 1 figur

Free-Range Pre-Programmed RC Car

There is a growing interest in the capabilities and utilization of autonomous vehicles. The objective of this project is to design a small scale illustration of an autonomous vehicle driven by user input. An application will be designed that will allow a user to create a track that an RC car will accurately follow. As the car follows the track, a microcontroller on the vehicle will send movement information back to the application. This information is used by the application to process where the vehicle is currently at and where it needs to go. While in motion, on-board sensors will actively detect obstacles in the path and adjust the vehicle’s direction to avoid collision

Survival in Patients Receiving Prolonged Ventilation: Factors that Influence Outcome

Background Prolonged mechanical ventilation is increasingly common. It is expensive and associated with significant morbidity and mortality. Our objective is to comprehensively characterize patients admitted to a Ventilator Rehabilitation Unit (VRU) for weaning and identify characteristics associated with survival. Methods 182 consecutive patients over 3.5 years admitted to Temple University Hospital (TUH) VRU were characterized. Data were derived from comprehensive chart review and a prospectively collected computerized database. Survival was determined by hospital records and social security death index and mailed questionnaires. Results Upon admission to the VRU, patients were hypoalbuminemic (albumin 2.3 ± 0.6 g/dL), anemic (hemoglobin 9.6 ± 1.4 g/dL), with moderate severity of illness (APACHE II score 10.7 + 4.1), and multiple comorbidities (Charlson index 4.3 + 2.3). In-hospital mortality (19%) was related to a higher Charlson Index score ( P = 0.006; OR 1.08-1.6), and APACHE II score ( P = 0.016; OR 1.03-1.29). In-hospital mortality was inversely related to admission albumin levels ( P = 0.023; OR 0.17-0.9). The presence of COPD as a comorbid illness or primary determinant of respiratory failure and higher VRU admission APACHE II score predicted higher long-term mortality. Conversely, higher VRU admission hemoglobin was associated with better long term survival (OR 0.57-0.90; P = 0.0006). Conclusion Patients receiving prolonged ventilation are hypoalbuminemic, anemic, have moderate severity of illness, and multiple comorbidities. Survival relates to these factors and the underlying illness precipitating respiratory failure, especially COPD