Productivity of Florida Springs: first semi-annual report to Biology Division, Office of Naval Research, progress from June 1, 1952 to January 31, 1953

Work has begun on studying the factors responsible for productivity in the Florida springs, which are nearly constant temperature, constant chemical, steady state giant laboratories. Progress has been made on five aspects: qualitative description, quantitative description, completion of knowledge of chemical factors, measurement of productivity , development of productivity theory. Measurement of the primary productivity in Silver Springs and Green Cove Springs by two new methods: the raising of organisms in cages, and the measurement of night & day differences in oxygen downstream agree roughly. Production in these springs is greater than previous production figures reported for marine, fresh water, and land areas. Instantaneous measures of production show large variations with season, time of day, cloud cover. Production estimates range from 11,000 lbs per acre per year to 70,000 lbs. glucose per acre per year during daylight hours. Essential stability of the springs environment has been shown with respect to temperature, phosphorus, and plant cover. A correlation of species number with lack of stability has been shown with insects. Quantitative studies have shown very large plant base to pyramids of mass. Correlation of marine invasion with chlorinity has been shown. The essential aspects of pH regulated phosphorus geochemistry in Florida have been outlined. Some theoretical ideas on productivity have been evolved. Mapping of sessile organisms in springs and taxonomic identification of dominants are half completed. Plans for second six months include measurement of herbivore and carnivore production rates and completion of food chain efficiency determinations in Silver Springs as a preparation for subsequent comparisons between springs. (34pp.

Hydraulic Lift and Soil Nutrient Heterogeneity

Water released at night from roots into upper portions of the soil profile in the process of hydraulic lift may contribute to reducing spatial soil nutrient heterogeneity. A manipulative field experiment was conducted in a semiarid shrub stand to determine if circumvention of hydraulic lift, by nighttime illumination of the shrub canopy, would result in greater soil nutrient heterogeneity than if the hydraulic lift process was allowed to operate. Nutrient-enriched patches were superimposed on the existing soil heterogeneity and after 40 days, the patches and interspaces were sampled for ions of different mobility and for root mass. There was no indication under these conditions that hydraulic lift was contributing to smoothing spatial nutrient heterogeneity

The impact of family and budget structure onhealth treatment in Nigeria

Health-treatment decisions, in much of the world, are affected by the family’s ability to meet thecost. In West Africa the situation is more complex because husbands and wives typically haveseparate budgets. This article reports an exploration of the impact on treatment of divided familybudgets in Nigeria where health services now charge for prescribed drugs. It was found that mostchild treatment is paid for by one person only, usually a parent, and that the treatment chosen isdecided by the person meeting the cost. Mothers are most likely to pay for minor illnesses but thefather’s role becomes more important as the cost rises. Because the type, and even fact, oftreatment depends on the ability to pay, and because the family is not a unity in these decisions,the health system may have to devise charging procedures that make both parents responsible,possibly with community involvement in securing paymen

Mars Exploration Rover Flight Operations Technical Consultation

The Mars Exploration Rover (MER) Project at the Jet Propulsion Laboratory developed two golf-cart size robotic vehicles, Spirit and Opportunity, for geological exploration of designated target areas on the surface of Mars. The primary scientific objective of these missions was the search for evidence of the presence of water on or near the surface of the planet during its history. Spirit and Opportunity were launched on June 10 and July 7, 2003, with their respective landings scheduled for January 4 and January 25, 2004 (UTC). NASA views the MER missions as particularly critical because of their scientific importance in the ongoing search for conditions under which life might have existed elsewhere in the solar system, because of their high level of public interest and because more than half of all prior missions launched to Mars internationally have failed. This report summarizes the findings and recommendations of the NASA Engineering and Safety Center review of the project

Comparative plasma catecholamine and hemodynamic responses to handgrip, cold pressor and supine bicycle exercise testing in normal subjects

Serial hemodynamic and plasma catecholamine responses were compared among 10 healthy men (27 ± 3 years) ( ± 1 standard deviation) during symptom-limited handgrip (33% maximal voluntary contraction for 4.4 ± 1.8 minutes), cold pressor testing (6 minutes) and symptom-limited supine bicycle exercise (22 ± 5 minutes). Plasma catecholamine concentrations were measured by radioenzymatic assays; ejection fraction and changes in cardiac volumes were assessed by equilibrium radionuclide angiography. During maximal supine exercise, plasma norepinephrine and epinephrine concentrations increased three to six times more than during either symptom-limited handgrip or cold pressor testing. Additionally, increases in heart rate, systolic blood pressure, rate-pressure product, stroke volume, ejection fraction and cardiac output were significantly greater during bicycle exercise than during the other two tests. A decrease in ejection fraction of 0.05 units or more was common in young normal subjects during the first 2 minutes of cold pressor testing (6 of 10 subjects) or at symptom-limited handgrip (3 of 10), but never occurred during maximal supine bicycle exercise.The magnitude of hemodynamic changes with maximal supine bicycle exercise was greater, more consistent and associated with much higher sympathetic nervous system activation, making this a potentially more useful diagnostic stress than either handgrip exercise or cold pressor testing

Towards an understanding of the rapid decline of the cosmic star formation rate

We present a first analysis of deep 24 micron observations with the Spitzer Space Telescope of a sample of nearly 1500 galaxies in a thin redshift slice, 0.65<z<0.75. We combine the infrared data with redshifts, rest-frame luminosities, and colors from COMBO-17, and with morphologies from Hubble Space Telescope images collected by the GEMS and GOODS projects. To characterize the decline in star-formation rate (SFR) since z~0.7, we estimate the total thermal infrared (IR) luminosities, SFRs, and stellar masses for the galaxies in this sample. At z~0.7, nearly 40% of intermediate and high-mass galaxies (with stellar masses >2x10^10 solar masses) are undergoing a period of intense star formation above their past-averaged SFR. In contrast, less than 1% of equally-massive galaxies in the local universe have similarly intense star formation activity. Morphologically-undisturbed galaxies dominate the total infrared luminosity density and SFR density: at z~0.7, more than half of the intensely star-forming galaxies have spiral morphologies, whereas less than \~30% are strongly interacting. Thus, a decline in major-merger rate is not the underlying cause of the rapid decline in cosmic SFR since z~0.7. Physical properties that do not strongly affect galaxy morphology - for example, gas consumption and weak interactions with small satellite galaxies - appear to be responsible.Comment: To appear in the Astrophysical Journal 1 June 2005. 14 pages with 8 embedded figure

Mass-to-Light Ratios for M31 Globular Clusters: Age-Dating and a Surprising Metallicity Trend

We have obtained velocity dispersions from Keck high-resolution integrated spectroscopy of ten M31 globular clusters (GCs), including three candidate intermediate-age GCs. We show that these candidates have the same V-band mass-to-light (M/L_V) ratios as the other GCs, implying that they are likely to be old. We also find a trend of derived velocity dispersion with wavelength, but cannot distinguish between a systematic error and a physical effect. Our new measurements are combined with photometric and spectroscopic data from the literature in a reanalysis of all M31 GC M/L_V values. In a combined sample of 27 GCs, we show that the metal-rich GCs have *lower* M/L_V than the metal-poor GCs, in conflict with predictions from stellar population models. Fragmentary data for other galaxies support this observation. The M31 GC fundamental plane is extremely tight, and we follow up an earlier suggestion by Djorgovski to show that the fundamental plane can be used to estimate accurate distances (potentially 10% or better).Comment: 34 pages, accepted to A

Linking Life Skills and Norms with adolescent substance use and delinquency in South Africa

We examined factors targeted in two popular prevention approaches with adolescent drug use and delinquency in South Africa. We hypothesized adolescent life skills to be inversely related, and perceived norms to be directly related to later drug use and delinquency. Multiple regression and a relative weights approach were conducted for each outcome using a sample of 714 South African adolescents ages 15 to 19 years (M = 15.8 years, 57% female). Perceived norms predicted gateway drug use. Conflict resolution skills (inversely) and perceived peer acceptability (directly) predicted harder drug use and delinquency. The “culture of violence” within some South African schools may make conflict resolution skills more salient for preventing harder drug use and delinquency.Department of HE and Training approved lis