Linking Theory and Practice for Restoration of Step-Pool Streams

Step-pools sequences are increasingly used to restore stream channels. This increase corresponds to significant advances in theory for step-pools in recent years. The need for step-pools in stream restoration arises as urban development encroaches into steep terrain in response to population pressures, as stream channels in lower-gradient areas require stabilization due to hydrological alterations associated with land-use changes, and as step-pools are recognized for their potential to enhance stream habitats. Despite an increasingly voluminous literature and great demand for restoration using step-pool sequences, however, the link between theory and practice is limited. In this article, we present four unique cases of stream restoration using step-pools, including the evolution of the approaches, the project designs, and adjustments in the system following restoration. Baxter Creek in El Cerrito, California demonstrates an early application of artificial step-pools in which natural adjustments occurred toward geomorphic stability and ecological improvement. Restoration of East Alamo Creek in a large residential development near San Ramon, California illustrates an example of step-pools increasingly used in locations where such a channel form would not naturally occur. Construction of a step-pool channel in Karnowsky Creek within the Siuslaw National Forest, Oregon overcame constraints posed by access and the type and availability of materials; the placement of logs allowed natural scouring below steps. Dry Canyon Creek on the property of the Mountains Restoration Trust in Calabasas, California afforded a somewhat experimental approach to designing step-pools, allowing observation and learning in the future. These cases demonstrate how theories and relationships developed for step-pool sequences over the past two decades have been applied in real-world settings. The lessons from these examples enable us to develop considerations useful for deriving an appropriate course of design, approval, and construction of artificial step-pool systems. They also raise additional fundamental questions concerning appropriate strategies for restoration of step-pool streams. Outstanding challenges are highlighted as opportunities for continuing theoretical work.     

Nitrate levels and the age of groundwater from the Upper Devonian sandstone aquifer in Fife,Scotland

The tritium concentrations in 13 groundwater samples from boreholes throughout the Upper Devonian sandstone aquifer of Fife have been measured. Due to atmospheric variations in tritium concentrations over the last century, this radioactive tracer can be used as a groundwater age indicator. In this study, the groundwater tritium concentrations have allowed for the area to be divided into three zones, and the variable chemistry of the groundwater samples, including the problem of recent elevated nitrate levels in the Fife Aquifer, has been interpreted in terms of their relative ages.     

Organochlorine pesticides in elementary school yards along the Texas-Mexico border

A reconnaissance study was undertaken to determine potential contaminant exposures to children through soil from elementary school playgrounds. Soil samples were collected from areas along the Texas-Mexico border, inland areas (soils from elementary school yards in cities/towns within the state of Texas), and three National Parks (one on the border, one in Tennessee, and one in Washington). The present study focused on organochlorine (OC) pesticides as the potential contaminants of concern because of their historical (and possibly current) use, and their importance as persistent organic pollutants (POPs). DDE and heptachlor were the most frequently detected OCs (69 and 63%, respectively), although heptachlor concentrations in soil never exceeded 5 ppb. Relatively higher concentrations of DDE were observed in agricultural areas along the border (50-60 ppb in soils from McAllen, Palmview, and San Benito) than in other soils. However, a school yard in Lubbock, TX had the highest OC concentration observed (70 ppb dieldrin). These results may be due to historical agriculture activity prior to the banning of OC pesticides such as DDT in the early 1970s, as well as the more recent use of DDT in Central and South America for malaria control.     

Normal and abnormal fetal cardiac anatomy

The heart is often perceived as a difficult organ to understand by ultrasound during fetal life. This is undoubtedly reflected in the low detection rate of cardiac abnormalities as compared to those of most other organ systems in the fetus. In this article we start by updating classical concepts of cardiac embryology, many of which were previously difficult to understand since they were overly simplistic or purely observational. We then lead on to the structure and growth of the fully formed fetal heart where we review the anatomy and ultrasound appearances in detail and provide comparisons with major abnormalities. We emphasise the fact that a solid understanding of cardiac anatomy can enable those involved in fetal medicine to make full use of the views of the heart that are obtained by ultrasound and which are often only transient. Copyright © 2004 John Wiley & Sons, Ltd.     

The effects of ammonium sulphate and urea upon egg hatching and miracidial survival of Schistosoma mansoni

The effects of various concentrations of ammonium sulphate and urea on egg hatching and miracidial survival of S. mansoni were tested in order to determine if the use of these fertilizers in the ricelands of the Republic of Cameroon could affect the transmission of schistosomiasis. Results indicate that hatching of eggs and survival of miracidia varied with concentrations of tested chemicals and times of exposure. Exposure of S. mansoni eggs to 0.20%-1.00% ammonium sulphate or to 0.50%-4.00% urea reduced their ability to hatch and produce miracidia. A chemical concentration of 1.00% ammonium sulphate or 4.00% urea was found to be sufficient to produce complete inhibition of hatching. High concentrations of both chemicals not only inhibited miracidial emergence but also may be ovocidal. Results obtained from miracidial survival tests indicated that LC5, LC50 and LC95 values for ammonium sulphate were 0.07%, 0.80% and 10.61% after 2 hours of exposure; 0.03%, 0.16% and 0.90% after 4 hours of exposure; and 0.30%, 0.20% and 0.40% after 6 hours of exposure respectively. Similar statistical analyses revealed that the LC5, LC50 and LC95 values for urea were 0.22%, 1.90% and 16.25% after 2 hours of exposure; 0.28%, 0.57% and 1.14% after 4 hours of exposure; and 0.13%, 0.27% and 0.57% after 6 hours of exposure respectively. Although the two fertilizers exerted some adverse effects on S. mansoni eggs and miracidia at relatively high concentrations, neither of them was found to be of practical value. Ammonium sulphate and urea concentrations effective in killing S. mansoni eggs and miracidia were about one to two orders of magnitude greater than the actual field application rates.     

Consumer response to integrated pest management and certification

This study investigated consumer awareness of integrated pest management (IPM) and the effects of two marketing strategies. Specific objectives were to find whether eastern Massachusetts farmstand and farmers' market customers purchasing sweet corn care how their food is grown, whether they are aware of IPM, whether they would prefer to buy IPM-certified sweet corn and why, and whether the marketing methods presently available to IPM-certified growers can enhance awareness of IPM. In 1993, the Massachusetts Department of Food and Agriculture in collaboration with the IPM Program at the University of Massachusetts began a pilot IPM certification program for sweet corn and strawberries, designated ‘Partners with Nature’ (PWN). This study compared a ‘passive’ and ‘active’ PWN marketing strategy with a control that did not have any PWN publicity. The passive strategy was simply display of a PWN certificate and poster. The active strategy also included newspaper advertisements, clear labeling of corn as IPM-certified at the point of selection, a PWN sticker placed on bags of corn at payment, personally thanking customers for ‘buying our IPM-certified sweet corn’, and IPM brochures available to customers. Thirty purchasers of IPM-grown corn were interviewed at each of six farmstands and six farmers' markets.The dominant reason why customers patronize farmstands and farmers' markets was convenience. As found by other northeastern surveys, awareness of IPM was low: only 19% had heard of IPM before the survey, and only 38% of these could mention a specific method used in IPM. Although 45% of the respondents initially said that they did not care how their food is grown, 85% said that they would prefer to buy IPM-certified sweet corn after hearing a short definition. The definition gave only environmental benefits, but 74% of the customers preferring IPM-certified corn said they would buy it because it is safer or healthier. Most of the respondents claimed that they would be willing to pay 10% more for IPM-certified corn. Simply displaying an IPM poster had no significant results on consumer preference for IPM-grown produce, but active marketing significantly raised awareness of IPM and the PWN program.This study demonstrated the willingness of customers to support IPM because they believe it will have positive consequences for human health and environmental quality. It is concluded that sweet corn marketing based on IPM certification positively influenced consumer reactions to IPM; and a more extensive, diverse marketing strategy would enhance consumer awareness and support.     

Sonographic demonstration of fetal sacrococcygeal teratoma

Six cases of sonographically diagnosed fetal sacrococcygeal teratoma (SCT) are presented and illustrate the variable features of fetal SCT. The sonographic findings assisted the parents and perinatal team in making decisions, and in two of the cases the children survived after elective Cesarean section and prompt neonatal resection of the tumors. None of the patients showed signs of malignant degeneration of the teratoma or metastases. Fetal SCT no longer should be considered a uniformly fatal condition. The literature on sacrococcygeal teratoma detected after birth indicates that the mortality rate is correlated with the degree of extension of the tumor. Therefore, the classification of sonographically diagnosed fetal SCT according to its size and position is important for decisions regarding pregnancy management.     

Reducing vulnerability to drought and famine: developmental approaches to relief

In this paper we present salient lessons learned through the International Relief/Development Project about the relationships between disasters and development. We discuss approaches to famine response and prevention, including the impact of global food distribution efforts on the capacities of people affected by famine and offer criteria for planning famine relief so that it will promote systemic, long term development of these capacities. We first describe a collaborative research project which showed that it is possible for international famine assistance either to promote the capacities of people who suffer from famine so that they are better able to handle future food crises, or to leave those it purports to help worse off and even more vulnerable to subsequent disasters. We then illustrate alternative strategies for promoting development in the midst of crisis by presenting information about a number of famine response programs and analyzing their impact on capacities and vulnerabilities.     

Indium detoxification in Pseudomonas fluorescens

The interaction between indium, a non-essential toxic element, and a soil bacterium was studied. Although the presence of 0.5 mm indium complexed to citrate, the sole source of carbon, had an inhibitory influence on growth rate and cellular yield, Pseudomonas fluorescens circumvented the toxicity of the trivalent metal via its insolubilization as a phosphorus residue. The inclusion of 20 microm iron (III) arrested the negative impact of indium and no diminution of cellular yield was recorded. In this instance indium homeostasis was also attained by elaboration of an extracellular phosphorus-containing deposit. Electrophoretic analyses of the cytoplasmic extracts revealed several dissimilar patterns. Notably, two polypeptides with apparent molecular masses of 57 kDa and 18 kDa were induced in the metal-stressed bacteria. An increment in extracellular carbohydrates in metal-supplemented media was observed. No citrate was detected in the spent fluid at the cessation of cellular bilization may have potential application in metal pollution management.