Duquesne University

About: Duquesne University is a education organization based out in Pittsburgh, Pennsylvania, United States. It is known for research contribution in the topics: Population & Health care. The organization has 3615 authors who have published 7169 publications receiving 180066 citations. The organization is also known as: Duquesne University of the Holy Spirit.

Evolution of Nitrate Reductase: Molecular and Structural Variations on a Common Function

Abstract: The biological transformation of nitrogen oxyanions is widespread in nature and gives rise to a robust biogeochemical cycle. The first step in nitrate reduction is carried out by the enzyme nitrate reductase (NR). Although NR always catalyzes the same chemical reaction (conversion of nitrate into nitrite), its location in the cell, structure, and function are organism-dependent. We use protein sequence data to determine phylogenetic relationships and to examine similarities in structure and function. Three distinct clades of NR are apparent: the eukaryotic assimilatory NR (Euk-NR) clade, the membrane-associated prokaryotic NR (Nar) clade, and a clade that includes both the periplasmic NR (Nap) and prokaryotic assimilatory NR (Nas). The high degree of sequence similarity and a phylogenetic distribution that follows taxonomic classification suggest a monophyletic origin for the Euk-NR early on in the evolution of eukaryotic cells. In contrast, sequence conservation, phylogenetic analysis, and physiology suggest that both Nar and Nap were acquired by horizontal gene transfer. Nap and Nas share a lesser degree of similarity, with Nap a subclade of Nas. Nap from strict anaerobic bacteria such as Desulfovibrio desulfuricans is ancestral to facultative species and may provide an evolutionary link between Nap and Nas. We observed conserved binding sites for molybdenum and pterin cofactors in all four proteins. In pathways involving Euk-NR, Nas, and Nar, for which ammonia is the end product, nitrite is reduced to ammonia by a siroheme nitrite reductase. Nap, however, is coupled to a pentaheme nitrite reductase. In denitrification, whether Nar or Nap is involved, nitrite is reduced to nitric oxide by either a cytochrome cd1 or a copper-containing nitrite reductase. This complexity underscores the importance of nitrate reduction as a key biological process.

Comparing the Quality of Students' Experiences During Cooperative Learning and Large-Group Instruction

Abstract: The authors compared the experiences of college students during cooperative learning and large-group instruction. Undergraduate educational psychology students were assigned to small groups to discuss how they could apply important psychological principles to teaching-learning projects. Students were interrupted during cooperative learning and large-group instruction so that the authors could measure perceptions of their experiences with the experience sampling method (M. Csikszentmihalyi, K. Rathunde, & S. Whalen, 1993). Overall quality of experience was greater during cooperative learning; benefits occurred specifically for thinking on task, student engagement, perceptions of task importance, and optimal levels of challenge and skill. Students were more self-conscious and reported more difficulty concentrating during cooperative learning. Quality of experience did not differ across instructional contexts for high- vs. low-achieving students; high-achieving students experienced greater overall quality of...

Primate Communication: A Multimodal Approach

Abstract: Primates communicate with each other using a wide range of signals: olfactory signals to mark territories, screams to recruit help while fighting, gestures to request food and facial expressions to initiate play Primate Communication brings together research on all forms of interchange and discusses what we know about primate communication via vocal, gestural, facial, olfactory and integrated multimodal signals in relation to a number of central topics It explores the morphological, neural and cognitive foundations of primate communication through discussion of cutting-edge research By considering signals from multiple modalities and taking a unified multimodal approach, the authors offer a uniquely holistic overview of primate communication, discussing what we know, what we don't know and what we may currently misunderstand about communication across these different forms It is essential reading for researchers interested in primate behaviour, communication and cognition, as well as students of primatology, psychology, anthropology and cognitive sciences

Understanding the Complexity of Becoming a Teacher Educator: Experience, belonging, and practice within a professional learning community

Abstract: This article reports a literature review of self-studies by beginning teacher educators examining their experiences of the transition from classroom teaching to teacher educator. The authors conclude that becoming a teacher educator involves several complex and challenging tasks: examining beliefs and values grounded in personal biography, including those associated with being a former schoolteacher; navigating the complex social and institutional contexts in which they work; and developing a personal pedagogy of teacher education that enables construction of a new professional identity as a teacher educator. This research provides beginning teacher educators with a reference point for understanding their personal and professional transition to university-based teacher education. It also provides teacher education faculty and administrators with key information about how the transition from teacher to teacher educator can be supported and enhanced within professional learning communities.