CEV Seat Attenuation System System Design Tasks

The Apollo crew / couch restraint system was designed to support and restrain three crew members during all phases of the mission from launch to landing. The crew couch used supported the crew for launch, landing and in-flight operations, and was foldable and removable for EVA ingress/egress through side hatch access and for in-flight access under the seat and in other areas of the crew compartment. The couch and the seat attenuation system was designed to control the impact loads imposed on the crew during landing and to remain non-functional during all other flight phases

The theory of heating of the quantum ground state of trapped ions

Using a displacement operator formalism, I analyse the depopulation of the vibrational ground state of trapped ions. Two heating times, one characterizing short time behaviour, the other long time behaviour are found. The short time behaviour is analyzed both for single and multiple ions, and a formula for the relative heating rates of different modes is derived. The possibility of correction of heating via the quantum Zeno effect, and the exploitation of the suppression of heating of higher modes to reduce errors in quantum computation is considered.Comment: 9 pages, 2 figure

Theory of Parabolic Arcs in Interstellar Scintillation Spectra

Our theory relates the secondary spectrum, the 2D power spectrum of the radio dynamic spectrum, to the scattered pulsar image in a thin scattering screen geometry. Recently discovered parabolic arcs in secondary spectra are generic features for media that scatter radiation at angles much larger than the rms scattering angle. Each point in the secondary spectrum maps particular values of differential arrival-time delay and fringe rate (or differential Doppler frequency) between pairs of components in the scattered image. Arcs correspond to a parabolic relation between these quantities through their common dependence on the angle of arrival of scattered components. Arcs appear even without consideration of the dispersive nature of the plasma. Arcs are more prominent in media with negligible inner scale and with shallow wavenumber spectra, such as the Kolmogorov spectrum, and when the scattered image is elongated along the velocity direction. The arc phenomenon can be used, therefore, to constrain the inner scale and the anisotropy of scattering irregularities for directions to nearby pulsars. Arcs are truncated by finite source size and thus provide sub micro arc sec resolution for probing emission regions in pulsars and compact active galactic nuclei. Multiple arcs sometimes seen signify two or more discrete scattering screens along the propagation path, and small arclets oriented oppositely to the main arc persisting for long durations indicate the occurrence of long-term multiple images from the scattering screen.Comment: 22 pages, 11 figures, submitted to the Astrophysical Journa

Preliminary Survey of Chemical Contaminants in Water, Sediment, and Aquatic Biota at Selected Sites in Northeastern Florida Bay and Canal C-111

Several actions are under way to alter water management capabilities and practices in south Florida in order to restore a more natural hydroperiod for the Everglades. Because relatively little research has been conducted on contaminants entering Florida Bay, we undertook a preliminary study in June 1995 to determine contaminant concentrations in surface water, sediment, and biota prior to major changes in water management. The areas studied were the C-111 canal (five sites) beginning just above water control structure S-197 and extending to Manatee Bay (part of the Biscayne Bay system), Shell Creek (three sites), the mouth of Taylor River, Trout Creek (two sites), and a site near the Key Largo Ranger Station. Hydrographic observations were made at each site, and samples of water and sediment were collected at each of the five areas except the Key Largo site. Bioresidues were determined for indigenous oysters collected from the C-111 canal and Shell Creek and for transplanted oysters exposed at the Key Largo site, the C-111 canal, Shell Creek, Taylor River, and Trout Creek for 5-29 days. Water samples were analyzed for selected organochlorine pesticides and metals; sediments were analyzed for the same compounds and for polycyclic aromatic hydrocarbons (PAHs). Fish filets and shucked oysters were analyzed for selected organochlorine pesticides, polychlorinated biphenyl (PCB) congeners, and metals. Other than low dissolved oxygen at some C-111 canal sites, water quality was generally good. Most contaminants were below water and sediment quality guidelines designed to protect aquatic life, and contaminant concentrations in oysters were low. Threshold effect levels were exceeded for some organochlorine pesticides and PAHs in some sediment samples, but all values measured were below probable effect levels. Low concentrations of organochlorine pesticides were detected in sediments from the C-111 canal, Shell Creek, Taylor River, and Trout Creek; except for Taylor River, low concentrations of PCB congeners and PAHs were detected from the same areas. The only organochlorine pesticide detected in filets from seven fish was 3.2 v-g DDE/kg (wet weight) in a sea catfish. Total mercury concentrations in filets of four species of fishes ranged from 0.53 to 1.3 μg/g, wet weight, which falls within a limited consumption advisory by the State of Florida

On the Representation Theory of an Algebra of Braids and Ties

We consider the algebra ${\cal E}_n(u)$ introduced by F. Aicardi and J. Juyumaya as an abstraction of the Yokonuma-Hecke algebra. We construct a tensor space representation for ${\cal E}_n(u)$ and show that this is faithful. We use it to give a basis for ${\cal E}_n(u)$ and to classify its irreducible representations.Comment: 24 pages. Final version. To appear in Journal of Algebraic Combinatorics

Adult hypertension referral pathway and therapeutic management:British and Irish Hypertension Society position statement

In the UK, most adults with hypertension are managed in Primary Care. Referrals to Secondary Care Hypertension Specialists are targeted to patients in whom further investigations are likely to change management decisions. In this position statement the British and Irish Hypertension Society provide clinicians with a framework for referring patients to Hypertension Specialists. Additional therapeutic advice is provided to optimise patient management whilst awaiting specialist review. Our aim is to ensure that referral criteria to Hypertension Specialists are consistent across the UK and Ireland to ensure equitable access for all patients