Modern Observational Techniques for Comets

Techniques are discussed in the following areas: astrometry, photometry, infrared observations, radio observations, spectroscopy, imaging of coma and tail, image processing of observation. The determination of the chemical composition and physical structure of comets is highlighted

The study of comets, part 1

Papers are presented dealing with observations of comets. Topic discussed include: photometry, polarimetry, and astrometry of comets; detection of water and molecular transitions in comets; ion motions in comet tails; determination of comet brightness and luminosity; and evolution of cometary orbits. Emphasis is placed on analysis of observations of comet Kohoutek

Evaluation of extractants for estimation of the phytoavailable trace metals in soils

Despite its environmental (and financial) importance, there is no agreement in the literature as to which extractant most accurately estimates the phytoavailability of trace metals in soils. A large dataset was taken from the literature, and the effectiveness of various extractants to predict the phytoavailability of Cd, Zn, Ni, Cu, and Pb examined across a range of soil types and contamination levels. The data suggest that generally, the total soil trace metal content, and trace metal concentrations determined by complexing agents (such as the widely used DTPA and EDTA extractants) or acid extractants (such as 0.1 M HCl and the Mehlich 1 extractant) are only poorly correlated to plant phytoavailability. Whilst there is no consensus, it would appear that neutral salt extractants (such as 0.01 M CaCl2 and 0.1 M NaNO3) provide the most useful indication of metal phytoavailability across a range of metals of interest, although further research is required

A search for interstellar molecules in the spectra of highly reddened stars

A total of ten stars were observed with cameras of the International Ultraviolet Explorer (IUE) in both high and low dispersion. One star, X Persei (HD 24534, 6.0 BE), was analyzed in detail. Ultraviolet observations of the column densities of CO match those derived from the radio to within a factor of 4, with the difference probably due to the larger beam size of the radio measurement and the assumption of a thermal population in the rotational levels of CO. Upper limits are given to the log column densities for OH, HCl, and CH2 of 14.0, 12.3 and 12.8. The carbon abundance was found to be about solar with a possible depletion of about a factor of 2. With precautions concerning both noise and correct background, the IUE can be used for studies of interstellar molecules

An Assessment of Potential Exposure and Risk from Estrogens in Drinking Water

BACKGROUND. Detection of estrogens in the environment has raised concerns in recent years because of their potential to affect both wildlife and humans. OBJECTIVES. We compared exposures to prescribed and naturally occurring estrogens in drinking water to exposures to naturally occurring background levels of estrogens in the diet of children and adults and to four independently derived acceptable daily intakes (ADIs) to determine whether drinking water intakes are larger or smaller than dietary intake or ADIs. METHODS. We used the Pharmaceutical Assessment and Transport Evaluation (PhATE) model to predict concentrations of estrogens potentially present in drinking water. Predicted drinking water concentrations were combined with default water intake rates to estimate drinking water exposures. Predicted drinking water intakes were compared to dietary intakes and also to ADIs. We present comparisons for individual estrogens as well as combined estrogens. RESULTS. In the analysis we estimated that a child's exposures to individual prescribed estrogens in drinking water are 730-480,000 times lower (depending upon estrogen type) than exposure to background levels of naturally occurring estrogens in milk. A child's exposure to total estrogens in drinking water (prescribed and naturally occurring) is about 150 times lower than exposure from milk. Adult margins of exposure (MOEs) based on total dietary exposure are about 2 times smaller than those for children. Margins of safety (MOSs) for an adult's exposure to total prescribed estrogens in drinking water vary from about 135 to > 17,000, depending on ADI. MOSs for exposure to total estrogens in drinking water are about 2 times lower than MOSs for prescribed estrogens. Depending on the ADI that is used, MOSs for young children range from 28 to 5,120 for total estrogens (including both prescribed and naturally occurring sources) in drinking water. CONCLUSIONS. The consistently large MOEs and MOSs strongly suggest that prescribed and total estrogens that may potentially be present in drinking water in the United States are not causing adverse effects in U.S. residents, including sensitive subpopulations.Johnson & Johnson Pharmaceutical Research and Development, LLC; Pfizer Inc.; Wyeth Inc

Antenatal ultrasound findings in cystic adenomatoid malformation

A case of congenital cystic adenomatoid malformation of the lung is presented with prenatal ultrasound findings. The present case appears to be the third instance reported in which the diagnosis was made antenatally by ultrasound, and the first which resulted in a live birth, although the patient succumbed to pulmonary hypoplasia.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46681/1/247_2004_Article_BF00975197.pd

Climatic controls on diffuse groundwater recharge across Australia

Reviews of field studies of groundwater recharge have attempted to investigate how climate characteristics control recharge, but due to a lack of data have not been able to draw any strong conclusions beyond that rainfall is the major determinant. This study has used numerical modelling for a range of Köppen-Geiger climate types (tropical, arid and temperate) to investigate the effect of climate variables on recharge for different soil and vegetation types. For the majority of climate types, the correlation between the modelled recharge and total annual rainfall is weaker than the correlation between recharge and the annual rainfall parameters reflecting rainfall intensity. Under similar soil and vegetation conditions for the same annual rainfall, annual recharge in regions with winter-dominated rainfall is greater than in regions with summer-dominated rainfall. The importance of climate parameters other than rainfall in recharge estimation is highest in the tropical climate type. Mean annual values of solar radiation and vapour pressure deficit show a greater importance in recharge estimation than mean annual values of the daily mean temperature. Climate parameters have the lowest relative importance in recharge estimation in the arid climate type (with cold winters) and the temperate climate type. For 75% of all soil, vegetation and climate types investigated, recharge elasticity varies between 2 and 4 indicating a 20% to 40% change in recharge for a 10% change in annual rainfall. Understanding how climate controls recharge under the observed historical climate allows more informed choices of analogue sites if they are to be used for climate change impact assessments

Poverty and poor education are key determinants of high household food insecurity among populations adjoining forest concessions in the Congo Basin

Background: The trees and non-timber forest products (NTFPs) of the Congo Basin play a key role in alleviating food insecurity among millions of people around the world. Although many studies have been conducted both nationally and regionally on issues of food insecurity in the Congo Basin, little is known on the effects of timber exploitation on household food insecurity statues of forest dependent communities in this region. This study focused on the determination of the principal indicators of household food security status of populations living around six selected forest concessions in the Congo Basin. Method: We randomly surveyed 724 households in thirty-four communities living in six popular forest concessions around the Congo Basin. Food consumption pattern data was collected using a validated food-frequency questionnaire in 2012. Household Food Insecurity Access Prevalence (HFIAP) was assessed using the HFIAP indicator and households were categorized into four levels of household food insecurity status as follows: Food secure (HFIAS = 0); mildly food insecure (HFIAS 1–8); moderately food insecure (HFIAS 9–13); and severely food insecure (HFIAS 14–27). Results: The majority of the households interviewed were headed by women (73.1 %, 76.6 %, and 58.6 % for Cameroon, DRC and Gabon respectively), most of them married (84.6 %, 100 %, 57.6 % for Cameroon, DRC and Gabon respectively) with an average age range of 30–49 years. Most of the household members were engaged in farming and/or illegal logging as the main revenue generating activities. Results of global household food insecurity categorized 63.8 % of households in Cameroon as fully food secure and 36 % as food insecure. In the DRC (92.9 %) and Gabon (92.7 %), almost all the survey households were categorized as either moderately or severely food insecure; clearly elucidating the existence of severe insufficiency in the quantity and quality of food meant for human nutrition in these areas. The means of household food insecurity scores for the DRC (17.40 ± 4.15) and Gabon (14.9 ± 5.87) were significantly higher when compared to the average score for Cameroon ((7.55 ± 6.62) at p < 0.0001. This literally means that many of the households especially in DRC and Gabon face enormous difficulties in obtaining an adequate dietary energy supply. Gender (female), educational level (illiterate), and age (young) were positively correlated to food insecurity levels. Conclusion: Our results revealed that, despite the potential contribution of the Congo Basin forests, through enhancing access to different forms of quality foods such as bush meat, wild foods, and medicine, not forgetting the provision of agricultural land, local construction material, and income generation resources, the prevalence of food insecurity among the population adjoining forest concessions in the region is severe. This prevalence is alarming around forest concessions of the DRC and Gabon and in one concession of Cameroon. Given that poverty and poor education were positively correlated to household food insecurity, they were considered the paramount determinants of household food insecurity in this region

A comparison of proximal and distal high-frequency jet ventilation in an experimental animal model

High-frequency jet ventilation using either a proximal or a distal endotracheal injection site through a triple-lumen endotracheal tube was studied in 10 adult cats. The comparative effects on pulmonary gas exchange, tracheal pressure, heart rate, and blood pressure were examined for each injection site at both high (8–12 pounds per square inch [PSI] and low (5–8 PSI) jet-driving pressures in normal and lung-injured cats. Lung injury was created by modification of a surfactant washout technique previously demonstrated in rabbits. Alveolar ventilation (Paco 2 ) was found to be significantly better with distal than with proximal jet injection under all experimental conditions. At high jet-driving pressures, peak inspiratory pressure was higher in both normal (p = 0.03) and lung-injured cats (p = 0.002) with distal high-frequency jet ventilation. In addition, lung-injured animals were observed to have higher distal mean airway pressures at high jet-driving pressures (p < 0.01). No differences in oxygenation were found in any circumstances. The results of this animal study suggest that distal high-frequency jet ventilation may be more effective in those situations in which improvement in alveolar ventilation is the major goal and that during proximal high-frequency jet ventilation airway pressures should be monitored as far distally as possible.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38592/1/1950020410_ftp.pd