Collapsing regions and black hole formation

Up to a conjecture in Riemannian geometry, we significantly strengthen a recent theorem of Eardley by proving that a compact region in an initial data surface that is collapsing sufficiently fast in comparison to its surface-to-volume ratio must contain a future trapped region. In addition to establishing this stronger result, the geometrical argument used does not require any asymptotic or energy conditions on the initial data. It follows that if such a region can be found in an asymptotically flat Cauchy surface of a spacetime satisfying the null-convergence condition, the spacetime must contain a black hole with the future trapped region therein. Further, up to another conjecture, we prove a strengthened version of our theorem by arguing that if a certain function (defined on the collection of compact subsets of the initial data surface that are themselves three-dimensional manifolds with boundary) is not strictly positive, then the initial data surface must contain a future trapped region. As a byproduct of this work, we offer a slightly generalized notion of a future trapped region as well as a new proof that future trapped regions lie within the black hole region.Comment: 11 pages, REVTeX 3.

Cooperative Interactive Distributed Guidance on Mobile Devices

Mobiles device are quickly becoming an indispensable part of our society. Equipped with numerous communication capabilities, they are increasingly being examined as potential tools for civilian and military usage to aide in distributed remote collaboration for dynamic decision making and physical task completion. With an ever growing mobile workforce, the need for remote assistance in aiding field workers who are confronted with situations outside their expertise certainly increases. Enhanced capabilities in using mobile devices could significantly improve numerous components of a task\u27s completion (i.e. accuracy, timing, etc.). This dissertation considers the design of mobile implementation of technology and communication capabilities to support interactive collaboration between distributed team members. Specifically, this body of research seeks to explore and understand how various multimodal remote assistances affect both the human user\u27s performance and the mobile device\u27s effectiveness when used during cooperative tasks. Additionally, power effects are additionally studied to assess the energy demands on a mobile device supporting multimodal communication. In a series of applied experiments and demonstrations, the effectiveness of a mobile device facilitating multimodal collaboration is analyzed through both empirical data collection and subjective exploration. The utility of the mobile interactive system and its configurations are examined to assess the impact on distributed task performance and collaborative dialogue between pairs. The dissertation formulates and defends an argument that multimodal communication capabilities should be incorporated into mobile communication channels to provide collaborating partners salient perspectives with a goal of reaching a mutual understanding of task procedures. The body of research discusses the findings of this investigation and highlight these findings they may influence future mobile research seeking to enhance interactive distributed guidance

Perceived Stress in the Field of Athletic Training

The purpose of this study was to determine the significance of the relationships between the three personal/situational variables and perceived stress, from R.E. Smith\u27s model, and how it related to the field of athletic training (Hendrix, et al., 140). The hypothesis for this study stated that perceived stress levels were more significantly related to hardiness and social support levels than to relevant work-related issue levels (i.e. athletic training issues) as they relate to the field of athletic training. Conversely, athletic training issues play a less significant role in perceived stress levels. Results from the study indicated that a fairly strong relationship existed between perceived stress and social support and between perceived stress and hardiness, A somewhat less significant relationship was also found to exist between perceived stress and athletic training issues. Therefore, based on the research, the first half of the hypothesis stating that perceived stress levels were more significantly related to hardiness and social support levels than to athletic training issue levels was supported. Secondly, the last half of the hypothesis stating that athletic training issues play a less significant role as related to perceived stress levels was also supported

The Design, Implementation, and Evaluation of a Pointing Device For a Wearable Computer

U.S. Air Force special tactics operators at times use small wearable computers (SWCs) for mission objectives. The primary pointing device of a SWC is either a touchpad or trackpoint, embedded into the chassis of the SWC. In situations where the user cannot directly interact with these pointing devices, the utility of the SWC is decreased. We developed a pointing device called the G3 that can be used for SWCs used by operators. The device utilizes gyroscopic sensors attached to the user’s index finger to move the computer cursor according to the angular velocity of his finger. We showed that, as measured by Fitts’s law, the overall performance and accuracy of the G3 was better than that of the touchpad and trackpoint. These findings suggest that the G3 can adequately be used with SWCs. Additionally, we investigated the G3\u27s utility as a control device for operating micro remotely piloted aircrafts

LabView Interface for School-Network DAQ Card

A low-cost DAQ card has been developed for school-network cosmic ray detector projects, providing digitized data from photomultiplier tubes via a standard serial interface. To facilitate analysis of these data and to provide students with a starting point for custom readout systems, a model interface has been developed using the National Instruments LabVIEW(R) system. This user-friendly interface allows one to initialize the trigger coincidence conditions for data-taking runs and to monitor incoming or pre-recorded data sets with updating singles- and coincidence-rate plots and other user-selectable histograms.Comment: 4 pages, 6 figures. Presented as Paper NS26-119 at IEEE-NSS 2003, Portland, OR, by R. J. Wilke

Hanover Bluffs : connections between the inner and outer landscapes.

Thesis. 1979. M.Arch.--Massachusetts Institute of Technology. Dept. of Architecture.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH.Bibliography: p. 101-102.M.Arch

Observation of direct hadronic pairs in nucleus-nucleus collisions in JACEE emulsion chambers

In a number of high energy ( or = 1 TeV/amu) nucleus-nucleus collisions observed in Japanese-American Cooperative Emulsion Experiment (JACEE) emulsion chambers, nonrandom spatial association of produced charged particles, mostly hadronic pairs, are observed. Similar narrow pairs are observed in about 100 events at much low energy (20 to 60 GeV/amu). Analysis shows that 30 to 50% of Pair abundances are understood by the Hambury-Brown-Twiss effect, and the remainder seems to require other explanations

Coyote, Canis latrans, Predation on a Bison, Bison bison, Calf in Yellowstone National Park

We observed a single adult male Coyote (Canis latrans) kill a Bison (Bison bison) calf in Yellowstone National Park. The predation is, to our knowledge, the only direct and complete observation of a lone Coyote capturing and killing a Bison calf. The bison calf had unsuccessfully attempted to ford a river with a group and subsequently become stranded alone in the territory of a six-year-old alpha male Coyote

Excessive production of electron pairs by soft photons in low multiplicity ion interactions

Three multiply charged primary cosmic ray interactions with carbon nuclei are reported, in which the number of materialized electron pairs within a distance of about 0.3 conversion length is larger than predicted from isospin considerations. These are the most energetic (sigma E gamma 4 TeV) of the low multiplicity ( 15 tracks) events observed in the Japanese-American Cooperative Experiment (JACEE-2) emulsion chamber