65,793 research outputs found
An Agent-Based Spatially Explicit Epidemiological Model in MASON
No full textThis paper outlines the design and implementation of an agent-based epidemiological simulation system. The system was implemented in the MASON toolkit, a set of Java-based agent-simulation libraries. This epidemiological simulation system is robust and extensible for multiple applications, including classroom demonstrations of many types of epidemics and detailed numerical experimentation on a particular disease. The application has been made available as an applet on the MASON web site, and as source code on the author\'s web site.Epidemiology, Social Networks, Agent-Based Simulation, MASON Toolkit
Mason Campus Water Quality Data (Fall 24- Spring 25)
No full textThis dataset contains water quality measurements collected from various stations (FFX 2, FFX 4, FFX 7, FFX 8, FFX 9, FFX 10, FFX 12, FFX 13, FFX 14) across the George Mason University campus in Fairfax, Virginia, between July 2024 and April 2025. Parameters measured include water temperature (°C), turbidity (NTU), conductivity (µS/cm), pH, dissolved oxygen (DO, mg/L), total dissolved solids (TDS, mg/L), and salinity. Sampling occurred approximately monthly, with some gaps or limitations due to low water levels (e.g., FFX 2 on March 11, 2025). Seasonal trends are observable across the dataset, with colder months showing lower temperatures and higher dissolved oxygen concentrations. Some readings are missing in spring 2025 for TDS and salinity due to incomplete sampling. The data capture spatial and temporal variability in water quality conditions across campus ponds and streams
SALICYLALDEHYDE-TAGGED PEPTIDES FOR THE REVERSIBLE-COVALENT ENGAGEMENT OF PROTEIN LYSINE RESIDUES
No full textInserting electrophilic species into small molecule ligands or peptides is a well-established method for enhancing binding affinity to target proteins. The amino acid Lysine (Lys) is highly abundant in the proteome and one of the most frequent residues on the outer structural layers of proteins. For these reasons, the derivatization of synthetic ligands with aldehyde tags capable of imine bond formation with Lys ɛ-amino groups may represent a general strategy for the discovery of potent small-molecule inhibitors.
Ortho-hydroxy aldehydes such as pyridoxal or salicylaldehyde (SA) derivatives have been used to form imines in aqueous media, stabilized by an intramolecular H-bond between the imine N atom and the ortho-phenolic proton. By virtue of this reactivity, SA derivatives are being installed into various classes of protein ligands, aimed at the reversible-covalent engagement of protein Lys residues.1,2
This talk will describe our recent contribution to this field, with focus on the installation of the Lys-engaging SA module into peptide ligands.3,4
Figure 1. Left: Binding mechanism of a reversible-covalent ligand equipped with a salicylaldehyde (SA) tag. Ideally, SA forms a remarkably stable imine bond with a Lys(ε-NH2) residue proximal to the ligand binding site. This covalent ligand-protein connection is stabilized by a H bond between the OH phenolic proton and the imine N atom. As a result, the final ligand-protein complex is stabilized by a combination of non-covalent and covalent interactions. Right: Current options for the SA tag installation at different peptide positions, recently developed by our group.
References
1. A. Dal Corso, M. Catalano, A. Schmid, J. Scheuermann, D. Neri, Angew. Chem. Int. Ed. 2018, 57, 17178.
2. M. Mason, L. Belvisi, L. Pignataro, A. Dal Corso, ChemBioChem 2023, e202300743.
3. G. Sacco, D. Arosio, M. Paolillo, A. Gloger, J. Scheuermann, L. Pignataro, L. Belvisi, A. Dal Corso, C. Gennari, Chem. Eur. J. 2023, e202203768.
4. M. Mason, B. Nava, L. Belvisi, L. Pignataro, A. Dal Corso, Eur. J. Org. Chem. 2024, 27, 202400229
Educational Plan of George Mason College of the University of Virginia, January 1968
No full textReport: 55 pg., typescript 8.5" X 11" (20.3 cm x 27.9 cm)1968 educational report on the future of George Mason College including enrollment, staff, programs, facilities and finances. George Mason University Archives, William H. McFarlane Papers, Box 3, Folder 65
Effects of critical thinking on multiple-document comprehension
No full textThe purpose of this study was to test the relationships between critical thinking, prior topic knowledge and beliefs, and multiple-document comprehension through a path analysis approach. The participants were 281 Italian undergraduate students. Participants first completed a rational-experiential inventory, a critical thinking skills test, a prior topic knowledge test, and a prior topic beliefs test. Then, they were asked to read six documents on the topic of flu vaccination. After reading the texts, students were asked to write an argumentative essay on the topic as a measure of multiple-document comprehension. The hypothesized model fit the data well. Results confirmed that argumentation quality after reading six documents with different perspectives on the topic is associated with different critical thinking skills in stronger- versus weaker-belief readers. In weaker-belief readers, multiple-document comprehension was associated with deduction skills, whereas in stronger-belief readers, multiple-document comprehension was associated with hypothesis-testing skills. Both theoretical and educational implications of the results are discussed
Neutrons in chemistry : contributions of single crystal neutron diffraction to coordination chemistry
No full text1. Introduction
Single crystal neutron diffraction is the technique of choice for unambiguously and accurately locating hydrogen atoms even in the presence of nearby “heavy atoms”. Recent advances in instrumentation and neutron sources are opening up new possibilities: in particular the use of fairly small crystals and short data collection times.
2. Results and Discussion
We will report three examples to illustrate the power of this technique in inorganic chemistry:
1) the first unambiguous structural evidence for non-conventional hydrogen bonding between a water molecule and a metal center in trans-[PtCl2(NH3)(N-glycine)]∙H2O.[1]
2) The coordination geometries of the binary platinum hydrides [Pt2(P-P)2(H)3]+ (P-P = dppb: 1,4–Bis(diphenylphosphino)butane and dpe: 1,2–Bis(diphenylphosphino)ethane).
3) The unambiguous location of deuterium atoms in the deuterated form of RuH2(η2-H2)2(PCyp3)2 (Cyp = cyclopentyl) complex as a proof of the metal-mediated C-H activation.[2]
3. References
[1] Silvia Rizzato, Jacqueline Bergès, Sax A. Mason, Alberto Albinati and Jiří Kozelka, Angew. Chem. Int. Ed., in press.
[2] M. Grellier, L. Vendier, B. Chaudret, A. Albinati, S. Rizzato, S. A. Mason and S. Sabo-Etienne J. Am. Chem. Soc., 2005,127 (50), 17593
Redescription of Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891 (Decapoda, Brachyura, Leucosiidae) from southeast India
No full textPrema, M., Ravichandran, S., Ng, Peter K. L. (2018): Redescription of Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891 (Decapoda, Brachyura, Leucosiidae) from southeast India. Zootaxa 4378 (1): 111-120, DOI: 10.11646/zootaxa.4378.1.
Honey bees and mason bees as biological indicators of landscape pesticide loads: Different results but similar conclusions
No full textAgricultural environments, including crop and non-crop areas, often provide important pollen and nectar resources for managed and wild bees. However, these resources may be contaminated with pesticides detrimental to bees and other non-target organisms, including humans. Differences in life-history traits among bee species influence food resource exploitation and pesticide exposure. This study assesses the potential of honey bees (Apis mellifera) and mason bees (Osmia), two bee species with highly contrasting functional traits, as biological indicators of pesticide exposure in 34 Italian agricultural farms. Pollen loads of both species were used to identify pollen species collected and to analyse multi-residue levels of pesticides. Pesticide risk indexes were calculated for honey bees, mason bees and humans. In mason bees, pesticide risk was not influenced by plant diversity. In agreement with their pollen preferences and short foraging ranges, mason bees collected a high proportion of pollen from flowers of the target crop. Conversely, pesticide risk decreased with increasing pollen diversity in honey bees. In agreement with their generalist foraging habits and long foraging ranges honey bees collected a greater diversity of pollen species and a lower proportion of target crop pollen. Although honey bees and mason bees showed similar toxic loads and pesticide composition, at a field scale pesticide risk of one species is not a good indicator of the risk to the other species. Our study confirms that bees in agricultural environments are pervasively exposed to multi-residue pesticide loads. Exposure is conditioned by specific bee traits but is also highly context-dependent
Exploiting D-Mason on parallel platforms: A novel communication strategy
No full textAgent-based simulation models are a powerful experimental tool for research and management in many scientific and technological fields.D-Mason is a parallel version of Mason, a library for writing and running Agent-based simulations.In this paper, we present a novel development of D-Mason, a decentralized communication strategy which realizes a Publish/Subscribe paradigm through a layer based on the MPI standard. We show that our communication mechanism is much more scalable and efficient than the previous centralized one
Learning from text, video, or subtitles: A comparative analysis
No full textThe present study investigated the influence of media (text, video, or subtitled video) on students' learning outcomes. Past studies have raised concerns about the effectiveness of learning from online videos over content-equivalent texts. Moreover, subtitled videos place additional demands on learning. Two-hundred and forty-seven undergraduate students were randomly assigned to a text, video, or subtitled-video condition, in a pretest, posttest, and delayed posttest design. The topic assigned was stem cells. Literal, inferential, and transfer questions were used to assess comprehension and learning outcomes. Results from the study confirmed the substantial equivalence of all conditions in immediate comprehension. Conversely, results confirmed the disadvantage of subtitled videos for deep learning outcomes
- …
