An evaluation of the utilization of remote sensing in resource and environmental management of the Chesapeake Bay region

A nine-month study was conducted to assess the effectiveness of the NASA Wallops Chesapeake Bay Ecological Program in remote sensing. The study consisted of a follow-up investigation and information analysis of actual cases in which remote sensing was utilized by management and research personnel in the Chesapeake Bay region. The study concludes that the NASA Wallops Chesapeake Bay Ecological Program is effective, both in terms of costs and performance

Contending with animal bones (Editorial)

[FIRST PARAGRAPH] This issue has been assembled in order to focus on some of the current directions in animal remains research. Since serious study of ancient animal remains began in the nineteenth century, this field and its specific areas of inquiry have evolved and diversified, and this collection of papers highlights that diversity, by including contributions that address issues from excavation and field recording methods and preservational conditions, to the use of bone for understanding past animal populations, as well as bones as proxy indicators for human activities. This volume is not meant only for the attention of the faunal remains specialist, and only a couple of these papers have actually been contributed by "archaeozoologists". Rather we hope to demonstrate the importance of faunal remains studies, on a par with lithic or pottery research. It should be acknowledged that animal bones do not relate simply to the “economic” aspects of a culture but to all areas of the life world

Provisions for nonintrusive flow-evaluation tools in the National Transonic Facility

The national transonic facility fan driven, closed circuit, continuous flow, pressurized wind tunnel is examined. The test section is 2.500 m x 2.500 m and 7.620 m long with a slotted wall configuration. There are six slots each in the top and bottom walls and two slots per sidewall. To maintain good flow quality and aerodynamic efficiency over the wide range of test capabilities the test section geometry is variable. The position of the test section and bottom walls, the reentry flaps at the rear of the test section slots, and the step height for reentering slot flow are remotely controlled. The test gas may be dry air or nitrogen, which for the elevated temperature (340 K) mode of operation the test medium is normally air, and heat removal is by a water cooled heat exchanger (cooling coil) located at the upstream end of the settling chamber. For the cryogenic mode of operation, heat removal is by evaporation of liquid nitrogen, which is sprayed into the circuit upstream of the fan. By utilizing liquid nitrogen as a coolant, the tunnel test temperature range is variable from 340 to 78 K. When nitrogen is injected into the circuit, venting must occur to maintain a constant pressure. Thermal insulation is installed internal to the pressure shell to minimize energy consumption

The late time evolution of Gamma-Ray Bursts: ending hyperaccretion and producing flares

We consider the properties of a hyperaccretion model for gamma-ray bursts (GRBs) at the late time when the mass supply rate is expected to decrease with time. We point out that the region in the vicinity of the accretor and the accretor itself can play an important role in determining the rate and time behavior of the accretion and ultimately the energy output. Motivated by numerical simulations and theoretical results, we conjecture that the energy release can be repeatedly stopped and then restarted by the magnetic flux accumulated around the accretor. We propose that the episode or episodes when the accretion resumes correspond to X-ray flares discovered recently in a number of GRBs.Comment: to appear in MNRAS Letters, revised versio

Artificial atmosphere control system

Two-gas control system has been developed which uses existing hardware. Three systems are used for control, monitoring, and safety backup. Pure oxygen will be supplied to maintain safe pressure level should something go wrong

A clinical informaticist to support primary care decision making

Objectives—To develop and evaluate an information service in which a "clinical informaticist" (a GP with training in evidence-based medicine) provided evidence-based answers to questions posed by GPs and nurse practitioners. Design—Descriptive pilot study with systematic recording of the process involved in searching for and critically appraising literature. Evaluation by questionnaire and semi-structured interview. Setting—General practice. Participants—34 clinicians from two London primary care groups (Fulham and Hammersmith). Main outcome measures—Number and origin of questions; process and time involved in producing summaries; satisfaction with the service. Results—All 100 clinicians in two primary care groups were approached. Thirty four agreed to participate, of whom 22 asked 60 questions over 10 months. Participants were highly satisfied with the summaries they received. For one third of questions the clinicians stated they would change practice in the index patient, and for 55% the participants stated they would change practice in other patients. Answering questions thoroughly was time consuming (median 130 minutes). The median turnaround time was 9 days; 82% of questions were answered within the timeframe specified by the questioner. Without the informaticist, one third of questions would not have been pursued. Conclusion—The clinical informaticist service increased access to evidence for busy clinicians. Satisfaction was high among users and clinicians stated that changes in practice would occur. However, uptake of the service was lower than expected (22% of those offered the service). Further research is needed into how this method of increasing access to evidence compares with other strategies, and whether it results in improved health outcomes for patients

Supplanting crystallography or supplementing microscopy? A combined approach to the study of an enveloped virus

The recent advances in the resolution obtained by single-particle reconstructions from cryo-electron microscopy (cryo-EM) have led to an increase in studies that combine X-ray crystallographic results with those of electron microscopy (EM). Here, such a combination is described in the determination of the structure of an enveloped animal virus, Semliki Forest virus, at 9 Å resolution. The issues of model bias in determination of the structure, the definition of resolution in a single-particle reconstruction, the effect of the correction of the contrast-transfer function on the structure determined and the use of a high-resolution structure of a subunit in the interpretation of the structure of the complex are addressed

Guide for users of the National Transonic Facility

The National Transonic Facility (NTF) is a fan-driven, closed-circuit, continuous flow, pressurized wind tunnel. The test section is 2.5 m x 2.5 m and 7.62 m long with a slotted-wall configuration. The NTF will have a Mach number range from 0.2 to 1.2, with Reynolds number up to 120 10 to the sixth power at Mach 1 (based on a reference length of 0.25 m). The pressure range for the facility will be from 1 to about 9 bars (1 ban = 100 kPa), and the temperature can be varied from 340 to 78 K. This report provides potential users of the NTF with the information required for preliminary planning to test programs and for preliminary layout of models and model supports which may be used in such programs

An experimental investigation of the interior noise control effects of propeller synchrophasing

A simplified cylindrical model of an aircraft fuselage is used to investigate the mechanisms of interior noise suppression using synchrophasing techniques. This investigation allows isolation of important parameters to define the characteristics of synchrophasing. The optimum synchrophase angle for maximum noise reduction is found for several interior microphone positions with pure tone source excitation. Noise reductions of up to 30 dB are shown for some microphone positions, however, overall reductions are less. A computer algorithm is developed to decompose the cylinder vibration into modal components over a wide range of synchrophase angles. The circumferential modal response of the shell vibration is shown to govern the transmission of sound into the cylinder rather than localized transmission. As well as investigating synchrophasing, the interior sound field due to sources typical of propellers has been measured and discussed

Numerical simulations of the seasonal/latitudinal variations of atomic oxygen and nitric oxide in the lower thermosphere and mesosphere

A 2-Dimensional zonally-averaged thermospheric model and the global University College London (UCL) thermospheric model have been used to investigate the seasonal, solar activity and geomagnetic variation of atomic oxygen and nitric oxide. The 2-dimensional model includes detailed oxygen and nitrogen chemistry, with appropriate completion of the energy equation, by adding the thermal infrared cooling by O and NO. This solution includes solar and auroral production of odd nitrogen compounds and metastable species. This model has been used for three investigations; firstly, to study the interactions between atmospheric dynamics and minor species transport and density; secondly, to examine the seasonal variations of atomic oxygen and nitric oxide within the upper mesosphere and thermosphere and their response to solar and geomagnetic activity variations; thirdly, to study the factor of 7 to 8 peak nitric oxide density increase as solar F sub 10.7 cm flux increases from 70 to 240 reported from the Solar Mesospheric Explorer. Auroral production of NO is shown to be the dominant source at high latitudes, generating peak NO densities a factor of 10 greater than typical number densities at low latitudes. At low latitudes, the predicted variation of the peak NO density, near 110 km, with the solar F sub 10.7 cm flux is rather smaller than is observed. This is most likely due to an overestimate of the soft X-ray flux at low solar activity, for times of extremely low support number, as occurred in June 1986. As observed on pressure levels, the variation of O density is small. The global circulation during solstice and periods of elevated geomagnetic activity causes depletion of O in regions of upwelling, and enhancements in regions of downwelling