1,159 research outputs found
On the Golay perfect binary code
AbstractSome combinatorial properties of the Golay binary code are emphasized and used for two main purposes. First, a new nonlinear code having 256 code words of length 16 at mutual distance 6 is exhibited. Second, a majority decoding method, quite similar to Massey's threshold decoding, is devised for the Golay code and various related codes
On Being Better but not Smarter than Others: The Muhammad Ali Effect
Past research suggests that people believe that they perform socially desirable behaviors more frequently and socially undesirable behaviors less frequently than others (Goethals, 1986; Messick, Bloom, Boldizar, & Samuelson, 1985). The present research examined whether this perception also characterizes people\u27s thinking about intelligent and unintelligent behaviors. In Study 1, subjects wrote lists of behaviors that they or others did. Subjects indicated that they performed more good and intelligent behaviors and fewer bad and unintelligent behaviors than others, although the magnitude of these differences was greater for good and bad acts than for intelligent and unintelligent ones. In Study 2, a different group of subjects judged the frequency with which the behaviors generated in the first study occur. While self-ascribed good behaviors were related as occurring more frequently than the good acts of others, self-ascribed intelligent behaviors were not judged as more frequent than the intelligent acts of others. Study 3 replicated this effect using a different methodology, finding that subjects indicated they would be more likely than their peers to perform moral behaviors, but no more likely to perform intellectual behaviors. A theoretical framework is proposed in which people\u27s positive beliefs about themselves are constrained by the publicity, specificity, and objectivity of the dimensions on which these beliefs are held
[Introduction to] Handbook of Heroism and Heroic Leadership
Over the past decade, research and theory on heroism and heroic leadership has greatly expanded, providing new insights on heroic behavior. The Handbook of Heroism and Heroic Leadership brings together new scholarship in this burgeoning field to build an important foundation for further multidisciplinary developments. In its three parts, Origins of Heroism, Types of Heroism, and Processes of Heroism, distinguished social scientists and researchers explore topics such as morality, resilience, courage, empathy, meaning, altruism, spirituality, and transformation. This handbook provides a much-needed consolidation and synthesis for heroism and heroic leadership scholars and graduate students.https://scholarship.richmond.edu/bookshelf/1293/thumbnail.jp
Predictability of marine nematode biodiversity
In this paper, we investigated: (1) the predictability of different aspects of biodiversity, (2) the effect of spatial autocorrelation on the predictability and (3) the environmental variables affecting the biodiversity of free-living marine nematodes on the Belgian Continental Shelf. An extensive historical database of free-living marine nematodes was employed to model different aspects of biodiversity: species richness, evenness, and taxonomic diversity. Artificial neural networks (ANNs), often considered as âblack boxesâ, were applied as a modeling tool. Three methods were used to reveal these âblack boxesâ and to identify the contributions of each environmental variable to the diversity indices. Since spatial autocorrelation is known to introduce bias in spatial analyses, Moran's I was used to test the spatial dependency of the diversity indices and the residuals of the model. The best predictions were made for evenness. Although species richness was quite accurately predicted as well, the residuals indicated a lack of performance of the model. Pure taxonomic diversity shows high spatial variability and is difficult to model. The biodiversity indices show a strong spatial dependency, opposed to the residuals of the models, indicating that the environmental variables explain the spatial variability of the diversity indices adequately. The most important environmental variables structuring evenness are clay and sand fraction, and the minimum annual total suspended matter. Species richness is also affected by the intensity of sand extraction and the amount of gravel of the sea bed
Conceptions of Leadership: Enduring Ideas and Emerging Insights
Conceptions of Leadership gathers together the latest work by distinguished leadership scholars in social psychology and related disciplines to explore classic conceptions of leadership, such as interpersonal influence, charisma, personality, and power, as well as recent perspectives on those enduring concerns. It includes contemporary departures from traditional approaches to leadership in considering gender, trust, narratives, and the complex relationships between leaders and followers. Together the chapters provide a wide-ranging and coherent account of how human beings get along and the ways they engage and work together to accomplish their goals.https://scholarship.richmond.edu/bookshelf/1198/thumbnail.jp
Radiosynthesis, in vitro and preliminary in vivo evaluation of the novel glutamine derived PET tracers [18F]fluorophenylglutamine and [18F]fluorobiphenylglutamine
INTRODUCTION: Glucose has been deemed the driving force of tumor growth for decades. However, research has shown that several tumors metabolically shift towards glutaminolysis. The development of radiolabeled glutamine derivatives could be a useful molecular imaging tool for visualizing these tumors. We elaborated on the glutamine-derived PET tracers by developing two novel probes, namely [(18)F]fluorophenylglutamine and [(18)F]fluorobiphenylglutamine MATERIALS AND METHODS: Both tracers were labelled with fluorine-18 using our recently reported ruthenium-based direct aromatic fluorination method. Their affinity was evaluated with a [(3)H]glutamine inhibition experiment in a human PC-3 and a rat F98 cell line. The imaging potential of [(18)F]fluorophenylglutamine and [(18)F]fluorobiphenylglutamine was tested using a mouse PC-3 and a rat F98 tumor model. RESULTS: The radiosynthesis of both tracers was successful with overall non-decay corrected yields of 18.46 ± 4.18 % (n=10) ([(18)F]fluorophenylglutamine) and 8.05 ± 3.25 % (n=5) ([(18)F]fluorobiphenylglutamine). In vitro inhibition experiments showed a moderate and low affinity of fluorophenylglutamine and fluorobiphenylglutamine, respectively, towards the human ASCT-2 transporter. Both compounds had a low affinity towards the rat ASCT-2 transporter. These results were endorsed by the in vivo experiments with low uptake of both tracers in the F98 rat xenograft, low uptake of [(18)F]FBPG in the mice PC-3 xenograft and a moderate uptake of [(18)F]FPG in the PC-3 tumors. CONCLUSION: We investigated the imaging potential of two novel PET radiotracers [(18)F]FPG and [(18)F]FBPG. [(18)F]FPG is the first example of a glutamine radiotracer derivatized with a phenyl group which enables the exploration of further derivatization of the phenyl group to increase the affinity and imaging qualities. We hypothesize that increasing the affinity of [(18)F]FPG by optimizing the substituents of the arene ring can result in a high-quality glutamine-based PET radiotracer. ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE: We hereby report novel glutamine-based PET-tracers. These tracers are tagged on the arene group with fluorine-18, hereby preventing in vivo defluorination, which can occur with alkyl labelled tracers (e.g. (2S,4R)4-[(18)F]fluoroglutamine). [(18)F]FPG shows clear tumor uptake in vivo, has no in vivo defluorination and has a straightforward production. We believe this tracer is a good starting point for the development of a high-quality tracer which is useful for the clinical visualization of the glutamine transport
Proton-counting radiography for proton therapy: a proof of principle using CMOS APS technology
Despite the early recognition of the potential of proton imaging to assist proton therapy (Cormack 1963 J. Appl. Phys. 34 2722), the modality is still removed from clinical practice, with various approaches in development. For proton-counting radiography applications such as computed tomography (CT), the water-equivalent-path-length that each proton has travelled through an imaged object must be inferred. Typically, scintillator-based technology has been used in various energy/range telescope designs. Here we propose a very different alternative of using radiation-hard CMOS active pixel sensor technology. The ability of such a sensor to resolve the passage of individual protons in a therapy beam has not been previously shown. Here, such capability is demonstrated using a 36 MeV cyclotron beam (University of Birmingham Cyclotron, Birmingham, UK) and a 200 MeV clinical radiotherapy beam (iThemba LABS, Cape Town, SA). The feasibility of tracking individual protons through multiple CMOS layers is also demonstrated using a two-layer stack of sensors. The chief advantages of this solution are the spatial discrimination of events intrinsic to pixelated sensors, combined with the potential provision of information on both the range and residual energy of a proton. The challenges in developing a practical system are discussed
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