Confluence Scour in Coarse Braided Streams

Laboratory models of a braided valley flat in coarse material were used in conjunction with field data to study confluence scour at braid anabranches. Correct prediction of the depth of scour is required for the design of buried pipeline crossings. Braid pattern and anabranches constantly shift and avulse so that scour holes have definable lifetimes. Although the scatter is large, the depth of water in the scour hole depends on confluence and relative anabranch discharge; this depth can be as high as six times the ambient depths in the anabranches

The speckled scallop, Argopecten circularis, in Aqua Hedionda Lagoon, San Diego County, California

Speckled scallops, Argopecten circularis (Sowerby, 1835), were sampled at Agua Hedionda Lagoon, Carlsbad, San Diego County from March 1984 to October 1986, to obtain basic life history data. Monthly samples of scallops were collected, measured, and released to obtain length frequency data for estimates of growth, life span, and spawning period. Subsamples of scallops were collected for determination of gonadal-somatic and adductor muscle-somatic indices. In 1984 large concentrations of speckled scallops were found on the sand-silt bottom of the lagoon, closely associated with eelgrass, Zostra marina. During the course of the study the numbers of scallops declined, until their virtual disappearance at the end of 1986. Monthly length frequency plots from 24,375 scallop measurements indicate that this is a rapidly growing species with a short life span. Gonadal- and adductor muscle-somatic indices from subsamples of 1,714 scallops indicate first spawning at age one and a relationship between temperature and spawning. Based on this study management recommendations are made for the speckled scallop. (39pp.

A variety of environmentally persistent chemicals, including some phthalate plasticizers, are weakly estrogenic

Sewage, a complex mixture of organic and inorganic chemicals, is considered to be a major source of environmental pollution. A random screen of 20 organic man-made chemicals present in liquid effluents revealed that half appeared able to interact with the estradiol receptor. This was demonstrated by their ability to inhibit binding of 17 beta-estradiol to the fish estrogen receptor. Further studies, using mammalian estrogen screens in vitro, revealed that the two phthalate esters butylbenzyl phthalate (BBP) and di-n-butylphthalate (DBP) and a food antioxidant, butylated hydroxyanisole (BHA) were estrogenic; however, they were all less estrogenic than the environmental estrogen octylphenol. Phthalate esters, used in the production of various plastics (including PVC), are among the most common industrial chemicals. Their ubiquity in the environment and tendency to bioconcentrate in animal fat are well known. Neither BBP nor DBP were able to act as antagonists, indicating that, in the presence of endogenous estrogens, their overall effect would be cumulative. Recently, it has been suggested that environmental estrogens may be etiological agents in several human diseases, including disorders of the male reproductive tract and breast and testicular cancers. The current finding that some phthalate compounds and some food additives are weakly estrogenic in vitro, needs to be supported by further studies on their effects in vivo before any conclusions can be made regarding their possible role in the development of these condition

Turbulent shear stresses in hydraulic jumps, bores and decelerating surges

In an open channel, a sudden rise in water level induces a positive surge, or bore, that may develop as a hydraulic jump in translation. When the surge propagates against an adverse slope, it decelerates until it becomes a stationary hydraulic jump. Both hydraulic jumps and decelerating surges induce some intense turbulent mixing and have some major impact on the sediment transport in natural systems. Herein, a physical investigation was conducted in a relatively large rectangular channel. Hydraulic jumps and surges were generated by the rapid closure of a gate at the channel downstream end. The turbulent shear stresses were measured with high temporal and spatial resolution (200 Hz sampling rate) in the jump flow. A comparison between the stationary hydraulic jump, hydraulic jump in translation and decelerating surge measurements showed some marked differences in terms of turbulent mixing. The results highlighted some intense mixing beneath the jump front and roller for all configurations. The levels of turbulent stresses were one to two orders of magnitude larger than a critical threshold for sediment motion. The findings provide some insights into the hydraulic jump migration processes in mobile bed channels, and the complex transformation from a moving jump into a stationary jump. Copyright (C) 2010 John Wiley & Sons, Ltd

Undergraduate Community Psychology Research Practice: The Story of the Community Narrative Research Project at Rhodes College

The Community Narrative Research Project (CNRP) is an undergraduate action research initiative focused on undergraduate students’ experiences of community engagement over time. At the center of the project is the collection and analysis of narratives written by Bonner Scholars at Rhodes College over their four years working in Memphis communities as part of their scholarship. This paper describes the participatory community research model that has evolved in the CNRP, including the voices of undergraduate student leaders in the Bonner Scholars program and undergraduate researchers in developmental and community psychology. We focus on the community of practice that has emerged in our team, and how this community grounds our interpretive and longitudinal analysis of the narratives we examine. Our discussion of the data analysis process, including students’ engagement with coding and reliability, illustrates the methodological repertoire that undergraduates develop in a community of practice and that is scaffolded by more experienced faculty and senior student researchers. Undergraduate students build the community psychology research and practice competencies that are often understood to be part of graduate student development. We are able to ask creative research questions informed by our unique and shared experiences, as well as our deep understanding of the data. We feature individual accounts by each of the six student authors to illustrate our research practice and share the experiences of team members. We offer practices that may be adapted to other undergraduate research contexts, and we discuss challenges and supports needed to sustain participatory action research with undergraduate students.&nbsp

Undergraduate Community Psychology Research Practice: The Story of the Community Narrative Research Project at Rhodes College

The Community Narrative Research Project (CNRP) is an undergraduate action research initiative focused on undergraduate students’ experiences of community engagement over time. At the center of the project is the collection and analysis of narratives written by Bonner Scholars at Rhodes College over their four years working in Memphis communities as part of their scholarship. This paper describes the participatory community research model that has evolved in the CNRP, including the voices of undergraduate student leaders in the Bonner Scholars program and undergraduate researchers in developmental and community psychology. We focus on the community of practice that has emerged in our team, and how this community grounds our interpretive and longitudinal analysis of the narratives we examine. Our discussion of the data analysis process, including students’ engagement with coding and reliability, illustrates the methodological repertoire that undergraduates develop in a community of practice and that is scaffolded by more experienced faculty and senior student researchers. Undergraduate students build the community psychology research and practice competencies that are often understood to be part of graduate student development. We are able to ask creative research questions informed by our unique and shared experiences, as well as our deep understanding of the data. We feature individual accounts by each of the six student authors to illustrate our research practice and share the experiences of team members. We offer practices that may be adapted to other undergraduate research contexts, and we discuss challenges and supports needed to sustain participatory action research with undergraduate students.&nbsp

Social factors associated with the decision to relinquish a baby for adoption

Little is known about the characteristics, social circumstances and mental health of women who give a child up for adoption. This paper reports data from a longitudinal study of 8556 women interviewed initially at their first obstetrical visit. In total, 7668 proceeded to give birth to a live singleton baby, of which 64 then relinquished the baby for adoption. Relinquishing mothers were predominantly 18 years of age or younger, in the lowest family income group, single, having an unplanned and/or unwanted baby and reported that they were not living with a partner. These women were somewhat more likely to manifest symptoms of anxiety and depression both prior, and subsequent to, the adoption, but the majority of relinquishing mothers were of 'normal' mental health. The decision to relinquish a baby appears to be a consequence of an unwanted pregnancy experienced by an economically deprived single mother rather than the result of emotional or psychological/psychiatric considerations. These findings document a particular dimension of the impact of poverty on health

The elusive source of quantum effectiveness

We discuss two qualities of quantum systems: various correlations existing between their subsystems and the distingushability of different quantum states. This is then applied to analysing quantum information processing. While quantum correlations, or entanglement, are clearly of paramount importance for efficient pure state manipulations, mixed states present a much richer arena and reveal a more subtle interplay between correlations and distinguishability. The current work explores a number of issues related with identifying the important ingredients needed for quantum information processing. We discuss the Deutsch-Jozsa algorithm, the Shor algorithm, the Grover algorithm and the power of a single qubit class of algorithms. One section is dedicated to cluster states where entanglement is crucial, but its precise role is highly counter-intuitive. Here we see that distinguishability becomes a more useful concept.Comment: 8 pages, no figure