Trichinae Certification in the United States Pork Industry

We report here on progress in the Trichinae Certification pilot program. This program uses an on-farm auditing system to document good production practices (GPPs) for swine relative to the risk of exposure to Trichinella spiralis. The pilot phase of this program continues while regulations to establish it as an official USDA program are being developed. Launch of the Trichinae Certification Program in the United States is expected to take place when regulations are finalized within the next year. The Trichinella certification program establishes a process for ensuring the quality and safety of animal-derived food products from the farm through slaughter

Trichinella Certification in the U.S. Pork Industry

We report here on a certification pilot study using an on-farm auditing system to document good production practices for swine relative to the risk of exposure to Trichinella spiralis. Based on the results, improvements in the program have been made and further piloting of the program is being undertaken prior to launching the Trichinae Certification Program in the United States. The Trichinella certification mechanism will establish a process for ensuring the quality and safety of animal-derived food products from the farm through slaughter

A Structural Model for Binding of the Serine-Rich Repeat Adhesin GspB to Host Carbohydrate Receptors

GspB is a serine-rich repeat (SRR) adhesin of Streptococcus gordonii that mediates binding of this organism to human platelets via its interaction with sialyl-T antigen on the receptor GPIbα. This interaction appears to be a major virulence determinant in the pathogenesis of infective endocarditis. To address the mechanism by which GspB recognizes its carbohydrate ligand, we determined the high-resolution x-ray crystal structure of the GspB binding region (GspBBR), both alone and in complex with a disaccharide precursor to sialyl-T antigen. Analysis of the GspBBR structure revealed that it is comprised of three independently folded subdomains or modules: 1) an Ig-fold resembling a CnaA domain from prokaryotic pathogens; 2) a second Ig-fold resembling the binding region of mammalian Siglecs; 3) a subdomain of unique fold. The disaccharide was found to bind in a pocket within the Siglec subdomain, but at a site distinct from that observed in mammalian Siglecs. Confirming the biological relevance of this binding pocket, we produced three isogenic variants of S. gordonii, each containing a single point mutation of a residue lining this binding pocket. These variants have reduced binding to carbohydrates of GPIbα. Further examination of purified GspBBR-R484E showed reduced binding to sialyl-T antigen while S. gordonii harboring this mutation did not efficiently bind platelets and showed a significant reduction in virulence, as measured by an animal model of endocarditis. Analysis of other SRR proteins revealed that the predicted binding regions of these adhesins also had a modular organization, with those known to bind carbohydrate receptors having modules homologous to the Siglec and Unique subdomains of GspBBR. This suggests that the binding specificity of the SRR family of adhesins is determined by the type and organization of discrete modules within the binding domains, which may affect the tropism of organisms for different tissues

Introduction: Toward an Engaged Feminist Heritage Praxis

We advocate a feminist approach to archaeological heritage work in order to transform heritage practice and the production of archaeological knowledge. We use an engaged feminist standpoint and situate intersubjectivity and intersectionality as critical components of this practice. An engaged feminist approach to heritage work allows the discipline to consider women’s, men’s, and gender non-conforming persons’ positions in the field, to reveal their contributions, to develop critical pedagogical approaches, and to rethink forms of representation. Throughout, we emphasize the intellectual labor of women of color, queer and gender non-conforming persons, and early white feminists in archaeology

Assessing the relation between language comprehension and performance in general chemistry

Few studies have focused specifically on the role that language plays in learning chemistry. We report here an investigation into the ability of language comprehension measures to predict performance in university introductory chemistry courses. This work is informed by theories of language comprehension, which posit that high-skilled comprehenders hold a cognitive advantage over the low-skilled because of a heightened ability to inhibit contextually irrelevant details and utilize prior knowledge to effectively bridge conceptual gaps when comprehending new information. Over a two-year period, data on comprehension ability, math ability, prior chemistry knowledge, and course performance were obtained in multiple general chemistry courses. Regression analyses and hierarchical linear models (HLMs) were utilized to establish relationships between predictor variables and course performance and to determine if comprehension ability could potentially compensate for low prior knowledge, a phenomenon predicted by theories of comprehension ability. Results indicate that comprehension ability correlates with general chemistry performance; it also contributes comparable information about course performance when compared to math ability and prior knowledge. In addition, we found that comprehension skill partially compensates for deficits in prior knowledge. Therefore, efforts to prepare students for success in general chemistry should include both content and the development of language comprehension skill

The Testing Effect: An Intervention on Behalf of Low-Skilled Comprehenders in General Chemistry

Past work has demonstrated that language comprehension ability correlates with general chemistry course performance with medium effect sizes. We demonstrate here that language comprehension’s strong cognitive grounding can be used to inform effective and equitable pedagogies, namely, instructional interventions that differentially aid low-skilled language comprehenders. We report the design, implementation, and assessment of such an intervention strategy. Guided by two models of comprehension, we predicted that a multiple pre-testing strategy would differentially aid low-skilled comprehenders in a general chemistry class. We also explored the effect of two question types (multiple choice and elaborative interrogation) on this intervention strategy. A within-subjects, learning-goals driven design was used to build the intervention into two semesters of the course; data generated by this approach were analyzed with hierarchical linear models. We found that the achievement gap between low- and high-skilled comprehenders was partially abated by repeated testing prior to course examinations. We also found that the differential benefits of repeated testing could be accounted for entirely by multiple-choice questions, while elaborative interrogation questions had a statistically significant, but negative, impact. The implication of this work for all levels of chemistry teaching is clear: testing can be used to enhance (not just to assess) student learning, and this act affects different groups of students in different ways