Triaxial digital fluxgate magnetometer for NASA applications explorer mission: Results of tests of critical elements

Tests performed to prove the critical elements of the triaxial digital fluxgate magnetometer design were described. A method for improving the linearity of the analog to digital converter portion of the instrument was studied in detail. A sawtooth waveform was added to the signal being measured before the A/D conversion, and averaging the digital readings over one cycle of the sawtooth. It was intended to reduce bit error nonlinearities present in the A/D converter which could be expected to be as much as 16 gamma if not reduced. No such nonlinearities were detected in the output of the instrument which included the feature designed to reduce these nonlinearities. However, a small scale nonlinearity of plus or minus 2 gamma with a 64 gamma repetition rate was observed in the unit tested. A design improvement intended to eliminate this small scale nonlinearity was examined

An exploration into the client at the heart of therapy : a qualitative perspective

Over 50 years ago Eysenck challenged the existing base of research into psychotherapy. Since that time, a large number of investigations have been conducted to verify the efficacy of therapy. Recently however, an increasing number of studies have cast new doubts on this research base. Instead of therapy being a function of the therapist, it is now becoming ever more apparent that the client plays a prime role in the therapeutic process. The qualitative studies presented in this paper provide some examples of research that demonstrates that clients are actively involved in their therapy, even making counselling work despite their counsellor. These studies suggest that clients may not experience therapy as beneficially as traditional outcome studies indicate. This raises a new challenge to researchers to more fully explore the client's experience of therapy, a challenge to which qualitative methods of inquiry would appear well suited

Multiple Sample Cryostat for the Determination of Superconductor Properties

Cryostats which are currently used to characterize the properties of superconductors between 4 K and 100 K are primarily single sample devices. The purpose of this paper is to present an instrument design which can hold up to five (5) one cm. diameter samples at a stable temperature (+ /-0.1K) within the above range specified while measurements of the sample properties are made

PCB Food web dynamics quantify nutrient and energy flow in aquatic ecosystems

Measuring in situ nutrient and energy flows in spatially and temporally complex aquatic ecosystems represents a major ecological challenge. Food web structure, energy and nutrient budgets are difficult to measure, and it is becoming more important to quantify both energy and nutrient flow to determine how food web processes and structure are being modified by multiple stressors. We propose that polychlorinated biphenyl (PCB) congeners represent an ideal tracer to quantify in situ energy and nutrient flow between trophic levels. Here, we demonstrate how an understanding of PCB congener bioaccumulation dynamics provides multiple direct measurements of energy and nutrient flow in aquatic food webs. To demonstrate this novel approach, we quantified nitrogen (N), phosphorus (P) and caloric turnover rates for Lake Huron lake trout, and reveal how these processes are regulated by both growth rate and fish life history. Although minimal nutrient recycling was observed in young growing fish, slow growing, older lake trout (\u3e 5 yr) recycled an average of 482 Tonnes∙yr-1of N, 45 Tonnes∙yr-1of P and assimilated 22 TJ yr-1of energy. Compared to total P loading rates of 590 Tonnes∙yr-1, the recycling of primarily bio available nutrients by fish plays an important role regulating the nutrient states of oligotrophic lakes

Quasars and Ultraluminous Infrared Galaxies: At the Limit?

We have detected the host galaxies of 16 nearby, radio-quiet quasars using images obtained with the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS). We confirm that these luminous quasars tend to live in luminous, early-type host galaxies, and we use the host-galaxy magnitudes to refine the luminosity/host-mass limit inferred from ground-based studies. If quasars obey the relation $M_{black hole}/M_{spheroid}\sim0.006$ found for massive dark objects in nonactive galaxies, then our analysis implies that they radiate at up to $\sim20$ of the Eddington rate. An analogous analysis for ultraluminous infrared galaxies shows them to accrete at up to similar Eddington fractions, consistent with the hypothesis that some of them are powered by embedded quasars.Comment: 9 pages, includes 2 eps figs, accepted to ApJLet

Using resilience assessments to inform the management and conservation of coral reef ecosystems

Climate change is causing the decline of coral reef ecosystems globally. Recent research highlights the importance of reducing CO2 emissions in combination with implementing local management actions to support reef health and recovery, particularly actions that protect sites which are more resilient to extreme events. Resilience assessments quantify the ecological, social, and environmental context of reefs through the lens of resilience, i.e., the capacity of a system to absorb or withstand stressors such that the system maintains its structure and functions and has the capacity to adapt to future disturbances and changes. Resilience assessments are an important tool to help marine managers and decision makers anticipate changes, identify areas with high survival prospects, and prioritize management actions to support resilience. While being widely implemented, however, there has not yet been an evaluation of whether resilience assessments have informed coral reef management. Here, we assess the primary and gray literature and input from coral reef managers to map where resilience assessments have been conducted. We explore if and how they have been used to inform management actions and provide recommendations for improving the likelihood that resilience assessments will result in management actions and positive conservation outcomes. These recommendations are applicable to other ecosystems in which resilience assessments are applied and will become increasingly important as climate impacts intensify and reduce the window of opportunity for protecting natural ecosystems

The gravitational lens MG0414+0534: a link between red galaxies and dust

We present near infrared observations of the red gravitational lens system MG0414+0534. Our images are of sufficient quality to allow photometry of all four QSO images and the lens galaxy. The observations show that the K-band brightnesses of the components are more similar to the radio brightnesses than to the optical and thus support the notion that the system is highly reddened. The differing brightnesses at visible wavelengths are interpreted as variable amounts of extinction in the lens galaxy. The lens galaxy is detected at K-band and is as red as any other known galaxy of comparable apparent magnitude. An estimate of the redshift of the lens galaxy of 0.45 < z < 0.6 is determined from the Faber-Jackson relation and photometric considerations. By extension we argue that other very red field galaxies may contain large amounts of dust. K-band spectra of the individual components show no difference in the H-alpha equivalent widths among the components. This is evidence against significant microlensing.Comment: 18 pages, including 7 figures, to appear in Astronomical Journal, April 198