A search for evidence of large body Earth impacts associated with biological crisis zones in the fossil record

The natural history of the Earth, how the present plant and animal species developed, how others completely died out, etc., was studied. The rock strata sampled and studied were at the time of deposition at sea bottom. It was found that, exactly at the stratigraphic level corresponding to the extinction, a thin clay layer was greatly enriched in the the rare element iridium. It was hypothesized that the excess irridium at the boundary came from a large steroid like object that hit the earth, and that the impact of this object threw up a dust cloud dense enough and long lasting enough to bring about the extinction of a wide variety of plants and animals, producing the unique break in in the fossil record, the cretaceous-tertiary boundary. The same iridium and platinum metals enrichement are found in a thin clay layer that corresponds with the boundary as difined by sudden radical changes in plant populations. The irridium enrichement is confirmed at other fresh water origin rites in the Raton Basin

Interplanetary propulsion using inertial fusion

Inertial fusion can be used to power spacecraft within the solar system and beyond. Such spacecraft have the potential for short-duration manned-mission performance exceeding other technologies. We are conducting a study to assess the systems aspects of inertial fusion as applied to such missions, based on the conceptual engine design of Hyde (1983) we describe the required systems for an entirely new spacecraft design called VISTA that is based on the use of DT fuel. We give preliminary design details for the power conversion and power conditioning systems for manned missions to Mars of total duration of about 100 days. Specific mission performance results will be published elsewhere, after the study has been completed

"I wouldn't choose that key ring; it's not me": A design study of cherished possessions and the self

Copyright © 2016 ACM. We each possess certain objects that are dear to us for a variety of reasons. They can be sentimental to us, bring us delight through their use or empower us. Throughout our lives, we use these cherished possessions to reaffirm who we are, who we were and who we wish to become. To explore this, we conducted a design study that asked ten participants to consider their emotional attachment towards and the identity-relevance of cherished and newly introduced possessions. Participants were then asked to elaborate on their responses in interviews. Through a thematic analysis of these responses, we found that the emotional significance of possessions was reportedly influenced by both their relevance to selfhood and position within a life story. We use these findings to discuss how the design of new products and systems can promote emotional attachment by holding a multitude of emotionally significant meanings to their owners

Distribution and Abundance of Submerged Aquatic Vegetation in 1984 and 1985

Communities of submerged aquatic vegetation (SA V) are an integral part of the Chesapeake Bay ecosystem. They provide an important habitat for many species, either as a food source or as protection from predators, i.e., as a nursery. By reducing currents and baffling waves, they allow for deposition of suspended material. In addition, they bind sediments with their roots and rhizomes to prevent erosion of the underlying material. They are important in nutrient cycling through both the absorption and release of nitrogen and phosphorus.https://scholarworks.wm.edu/vimsbooks/1165/thumbnail.jp

The VISTA spacecraft: Advantages of ICF (Inertial Confinement Fusion) for interplanetary fusions propulsion applications

Inertial Confinement Fusion (ICF) is an attractive engine power source for interplanetary manned spacecraft, especially for near-term missions requiring minimum flight duration, because ICF has inherent high power-to-mass ratios and high specific impulses. We have developed a new vehicle concept called VISTA that uses ICF and is capable of round-trip manned missions to Mars in 100 days using A.D. 2020 technology. We describe VISTA's engine operation, discuss associated plasma issues, and describe the advantages of DT fuel for near-term applications. Although ICF is potentially superior to non-fusion technologies for near-term interplanetary transport, the performance capabilities of VISTA cannot be meaningfully compared with those of magnetic-fusion systems because of the lack of a comparable study of the magnetic-fusion systems. We urge that such a study be conducted

Vacuum energy in the presence of a magnetic string with delta function profile

We present a calculation of the ground state energy of massive spinor fields and massive scalar fields in the background of an inhomogeneous magnetic string with potential given by a delta function. The zeta functional regularization is used and the lowest heat kernel coefficients are calculated. The rest of the analytical calculation adopts the Jost function formalism. In the numerical part of the work the renormalized vacuum energy as a function of the radius $R$ of the string is calculated and plotted for various values of the strength of the potential. The sign of the energy is found to change with the radius. For both scalar and spinor fields the renormalized energy shows no logarithmic behaviour in the limit $R\to 0$, as was expected from the vanishing of the heat kernel coefficient $A_2$, which is not zero for other types of profiles.Comment: 30 pages, 10 figure

Dissipative Quantum Ising model in a cold atomic spin-boson mixture

Using cold bosonic atoms with two (hyperfine) ground states, we introduce a spin-boson mixture which allows to implement the quantum Ising model in a tunable dissipative environment. The first specie lies in a deep optical lattice with tightly confining wells and forms a spin array; spin-up/down corresponds to occupation by one/no atom at each site. The second specie forms a superfluid reservoir. Different species are coupled coherently via laser transitions and collisions. Whereas the laser coupling mimics a transverse field for the spins, the coupling to the reservoir sound modes induces a ferromagnetic (Ising) coupling as well as dissipation. This gives rise to an order-disorder quantum phase transition where the effect of dissipation can be studied in a controllable manner.Comment: 4 pages, 2 figures, 1 table; Title modified and cosmetic change

Designing memory probes to inform dialogue

© 2017 ACM. To investigate the phenomenon that occurs during interactions between used objects and autobiographical memories, which are both ever-changing and imbedded with personal significance, an adapted probing method capable of managing these complex qualities is needed. This pictorial is our attempt to find a nuanced indication of how probes could go beyond common usage to facilitate complex felt experience, and how probes can be used in less prescriptive ways to instead promote reminiscent dialogues that are rich and open to interpretation for both participants and researchers. It illustrates our exploration into potential Memory Probes and how this might be done that reflects the value we see in creating restrictions or limitations in technologymediated interactions to encourage active participation by users in social acts such as memory creation and remembrance

Designing meaningful products in the digital age: How users value their technological possessions

© 2019 Association for Computing Machinery. Devices such as phones, laptops and tablets have become central to the ways in which many people communicate with others, conduct business and spend their leisure time. This type of product uniquely contains both physical and digital components that affect how they are perceived and valued by users. This article investigates the nature of attachment in the context of technological possessions to better understand ways in which designers can create devices that are meaningful and kept for longer. Findings from our study of the self-reported associations and meaningfulness of technological possessions revealed that the digital contents of these possessions were often the primary source of meaning. Technological possessions were frequently perceived as systems of products rather than as singular devices. We identified several design opportunities for materialising the associations ascribed to the digital information contained within technological products to more meaningfully integrate their physical and digital components