53,941 research outputs found
A Tribute to the Ladies
The legendary Cokie Roberts dishes on Martha, Dolley and our country’s Founding Mothers
[Review of] Ernest R. Myers, The Community Psychology Concept: Integrating Theory, Education, and Practice in Psychology, Social Work, and Public Administration
Psychologists and other social scientists are critically analyzing the “state of the art” of community psychology. Their question is how this developing discipline can be best organized for pursuit of knowledge needed to bring about positive community change
Developments in plant breeding for improved nutritional quality of soya beans I. Protein and amino acid content
Soya beans, like other legumes, contain low concentrations of the nutritionally essential sulphur amino acid, methionine. Cysteine, although not an essential amino acid because it can be synthesized from methionine, also influences the nutritional quality of soya bean products when it is only present in low levels. A low cysteine content will also aggravate a methionine deficiency. Soya bean lines deficient in 7S protein subunits have been identified. The 7S proteins contain substantially less methionine and cysteine than the 11S proteins. With the myriad of genetic null alleles for these subunits it may be possible to tailor the 7S/11S storage protein ratio and their total composition in seeds to include only those subunits with the richest sulphur amino acid composition. Cotyledon feeding experiments, using isolated soya bean cotyledons, demonstrated that addition of methionine to the culture media caused increased synthesis of both proteins and free amino acids but the mechanism by which this takes place is not clear
Developments in plant breeding for improved nutritional quality of soya beans II. Anti-nutritional factors
Nutritional value of most plant materials is limited by the presence of numerous naturally occurring compounds which interfere with nutrient digestion and absorption. Although processing is employed widely in removal of these factors, selection of cultivars of soya beans with inherently low levels would have a considerable impact on efficiency of non-ruminant livestock production. The review considers the role of plant breeding in achieving this objective. The most abundant trypsin inhibitors are the Kunitz and the Bowman Birk inhibitors, containing 181 and 71 amino acids respectively. The Kunitz inhibitor is present at a concentration of 1.4g/kg of total seed contents and the Bowman Birk inhibitor 1.6g/kg. A large number of isoforms of the Bowman Birk inhibitor have been described in soya bean cultivars and it has been shown that the general properties of the inhibitor are, in fact, attributable to different isoforms. Nulls for both Bowman-Birk and Kunitz trypsin inhibitors have been identified, allowing new low trypsin inhibitor cultivars to be produced. However, research into breeding for low trypsin inhibitor cultivars currently has limited application as trypsin inhibitors contribute a major proportion of the methionine content of soya beans. Trypsin inhibitors are thought to be involved in the regulation of and protection against unwanted proteolysis in plant tissues and also act as a defense mechanism against attack from diseases, insects and animals. Hence, in breeding programes for low trypsin inhibitor cultivars, alternative protection for growing plants must be considered. Use of soya beans in non-ruminant animal feeds is limited by the flatulence associated with their consumption
Vacuum forming of thermoplastic sheet results in low-cost investment casting patterns
Vacuum forming of a sheet of thermoplastic material around a mandrel conforming to the shape of the finished object provides a pattern for an investment mold. The thickness of the metal part is determined by the thickness of the plastic pattern
The Impact of Acoustic Imaging Geometry on the Fidelity of Seabed Bathymetric Models
Attributes derived from digital bathymetric models (DBM) are a powerful means of analyzing seabed characteristics. Those models however are inherently constrained by the method of seabed sampling. Most bathymetric models are derived by collating a number of discrete corridors of multibeam sonar data. Within each corridor the data are collected over a wide range of distances, azimuths and elevation angles and thus the quality varies significantly. That variability therefore becomes imprinted into the DBM. Subsequent users of the DBM, unfamiliar with the original acquisition geometry, may potentially misinterpret such variability as attributes of the seabed. This paper examines the impact on accuracy and resolution of the resultant derived model as a function of the imaging geometry. This can be broken down into the range, angle, azimuth, density and overlap attributes. These attributes in turn are impacted by the sonar configuration including beam widths, beam spacing, bottom detection algorithms, stabilization strategies, platform speed and stability. Superimposed over the imaging geometry are residual effects due to imperfect integration of ancillary sensors. As the platform (normally a surface vessel), is moving with characteristic motions resulting from the ocean wave spectrum, periodic residuals in the seafloor can become imprinted that may again be misinterpreted as geomorphological information
First wide-angle view of channelized turbidity currents links migrating cyclic steps to flow characteristics
Field observations of turbidity currents remain scarce, and thus there is continued debate about their internal structure and how they modify underlying bedforms. Here, I present the results of a new imaging method that examines multiple surge-like turbidity currents within a delta front channel, as they pass over crescent-shaped bedforms. Seven discrete flows over a 2-h period vary in speed from 0.5 to 3.0 ms−1. Only flows that exhibit a distinct acoustically attenuating layer at the base, appear to cause bedform migration. That layer thickens abruptly downstream of the bottom of the lee slope of the bedform, and the upper surface of the layer fluctuates rapidly at that point. The basal layer is inferred to reflect a strong near-bed gradient in density and the thickening is interpreted as a hydraulic jump. These results represent field-scale flow observations in support of a cyclic step origin of crescent-shaped bedforms
Russell Square: a lifelong resource for teaching and learning
A quarter of a century ago, in 1978, Birkbeck College’s Faculty of Continuing Education (FCE, then the Department for Extra-Mural Studies of the federal University) moved to the offices that it now occupies in numbers 26 and 25 Russell Square. Then, as now, FCE was the one of the largest and most active extra-mural departments of any British university, with an enormous range of courses covering virtually every subject taught in ‘internal’ university departments and many more besides 1. Some of these courses have, from time to time, used Russell Square as a learning resource. Many more staff and students alike have (along with thousands of local workers, tourists and residents) used the square’s gardens for relaxation and recovery, without reflecting on its origins or present significance.
This Occasional Paper examines the past and present fabric of Russell Square (‘the Square’) as a resource for teaching and learning. It is a composite narrative assembled by FCE staff whose disciplines range from nature conservation through garden history and architectural history to social policy. It deconstructs the Square as an entity and attempts to decipher some of its ‘meanings’ that provide links between subjects taught within FCE.
We hope that it will stimulate discussion about the way this single ‘place’ – our Square - can be ‘seen’ or interpreted in different ways for diverse purposes, and about the way that it can be used as a resource for teaching and learning across disciplines
- …