Bucknell University
  • Lewisburg, PA, United States
Recent publications
This article develops a small-scale evolutionary agent-based model to investigate the interplay between heterogeneous agents, institutions and technological change. By acknowledging the concept of behavioural dispositions, we differentiate between changers, neutrals, and deniers. The composition of the population is endogenously determined taking into account that reasoning is context-dependent. As we increase the degree of interaction between agents, a bi-modal distribution with two different basins of attraction emerges: one around an equilibrium with the majority of the population supporting innovative change, and another with most agents being suspicious of innovation. Neutral agents play an important role as an element of resilience. Conditional on their share in equilibrium, an increase in the response of the respective probability functions to growth results in a super-critical Hopf-bifurcation, followed by the emergence of persistent fluctuations. Numerical experiments on the basin of attraction also reveal the birth of an additional periodic attractor. A long-run cycle of technological and institutional change may coexist with locally stable fixed points. Our results indicate that economies are more likely to be path-dependent than what conventional approaches usually admit.
A High Rigidity Spectrometer (HRS) has been designed for experiments at the Facility for Rare-Isotope Beams (FRIB) at Michigan State University (MSU). The HRS will allow experiments to be performed with the most exotic neutron-rich isotopes at high beam energies (≳100 MeV/u). The HRS consists of an analysis beamline called the High-Transmission Beamline (HTBL) and the spectrometer proper called the Spectrometer Section. The maximum magnetic rigidity of the HRS is 8 Tm, which corresponds to the rigidities at which rare-isotope beams are optimally produced at FRIB. The resolving power, angular acceptance, and momentum acceptance are set to match the anticipated scientific program. An ion-optical design developed for the HRS is described in detail, along with the specifications of the associated magnet and detector systems.
Engaged students desire to do well, while course instructors endeavor to create a course environment that will achieve long-term mastery of the subject and student success in the classroom and beyond. Despite the effort put forth by both parties, the result is sometimes less favorable than expected. Studies have shown that people tend to overestimate their own abilities (“overconfidence”). When students are overconfident it leads them to believe that they know more than they actually do and consequently study less, while basing their expectations on what grade they would like to achieve, all of which further serves to compound the problem. There is no reason to believe that this does not also apply to real estate students. Indeed, using data from three different universities the authors seek to determine whether real estate students, both undergraduate and graduate, are able to accurately self-evaluate their own ability, both relative to their own performance, and vis-a-vis what they believed that the class average would be. We seek to determine if 1) students can properly self-assess their ability as measured by performance, 2) if any overconfidence exists relative to their expectations compared to their estimation of their peers, and 3) if overconfidence does exist, are there specific factors that influence them such as gender. The results presented in this paper are useful for a real estate instructor to manage expectations and provide a better learning environment.
The double angle chords of open-web steel joists are often designed to efficiently support loading with relatively slender sections, which introduces buckling instabilities that are treated differently by various design standards. This study investigates the buckling behavior of double angles, focusing on the importance of flexural–torsional buckling. A theoretical inelastic buckling investigation considering current design practices and known steel behavior demonstrates how flexural–torsional buckling does not control for all double angle configurations. Subsequent investigation focuses on double angles theoretically susceptible to flexural–torsional buckling, while implementing finite element modeling of full joist structures and isolated chord segments. The resulting elastic eigenbuckling analysis and geometrically and materially nonlinear analysis with imperfections captures significant twisting of individual angles in the built-up section; however, global flexural–torsional buckling was not observed to control. Most double angle configurations are controlled by flexural buckling due to an increased flexural–torsional buckling capacity. This result is attributed to the observed increased torsional stiffness of the chords, which is typically not considered in design. A supplementary investigation indicated this torsional stiffness was primarily a result of torsion being transferred through the stiff chord-to-chord connections, which do not exist in all double angle members. Accounting for the additional torsional stiffness in a theoretical inelastic buckling calculation leads to flexural–torsional buckling not controlling the design of most double angle cross sections considered in this study. Overall, this study indicates that designing double angles in joist structures by only considering flexural buckling with local buckling is reasonable with current industry practices.
Adults are able to use visual prosodic cues in the speaker's face to segment speech. Furthermore, eye-tracking data suggest that learners will shift their gaze to the mouth during visual speech segmentation. Although these findings suggest that the mouth may be viewed more than the eyes or nose during visual speech segmentation, no study has examined the direct functional importance of individual features; thus, it is unclear which visual prosodic cues are important for word segmentation. In this study, we examined the impact of first removing (Experiment 1) and then isolating (Experiment 2) individual facial features on visual speech segmentation. Segmentation performance was above chance in all conditions except for when the visual display was restricted to the eye region (eyes only condition in Experiment 2). This suggests that participants were able to segment speech when they could visually access the mouth but not when the mouth was completely removed from the visual display, providing evidence that visual prosodic cues conveyed by the mouth are sufficient and likely necessary for visual speech segmentation.
The linear form of the nondimensional complementary relationship (CR) follows from an isenthalpic process of evaporation under a constant surface available energy and unchanging wind. Mixing of external moisture into the boundary layer (BL) alters the dry‐end second‐type boundary condition yielding a polynomial that can be further generalized into a three‐parameter (Priestley‐Taylor α, a, b) power function (PF3), capable of responding to the level of such admixing. With the help of FLUXNET data and setting a = 2 for a possible recapture of the linear and/or polynomial versions of the CR, it is demonstrated that the resulting two‐parameter PF (i.e., PF2) excels among the CR‐based two‐parameter models considered in this study. PF2 is then employed with a globally set constant value of α = 1.1 and 0.5° monthly data across Australia, while calibrating b against the multiyear water‐balance evaporation rate on a cell‐by‐cell basis. The resulting bi‐modal histogram peaks first near b = 2 (recapturing the polynomial CR) when moisture admixing is significant, and then at b → 1 (yielding the linear CR) when mixing effects are negligible. Unlike the linear or polynomial CR versions, PF2 can respond to the general efficiency of external moisture admixing through its parameter b, making it applicable even near sudden discontinuities in surface moisture. A new duality emerges with the PF2: while α accounts for the effect of entrainment of free tropospheric drier air into the BL on the resulting wet‐environment evaporation rate, b does so for moisture on the drying‐environment evaporation rates.
Actin plays a vital role in maintaining the stability and rigidity of biological cells while allowing for cell motility and shape change. The semiflexible nature of actin filaments—along with the myriad actin-binding proteins (ABPs) that serve to crosslink, bundle, and stabilize filaments—are central to this multifunctionality. The effect of ABPs on the structural and mechanical properties of actin networks has been the topic of fervent investigation over the past few decades. Yet, the combined impact of filament stabilization, stiffening and crosslinking via ABPs on the mechanical response of actin networks has yet to be explored. Here, we perform optical tweezers microrheology measurements to characterize the nonlinear force response and relaxation dynamics of actin networks in the presence of varying concentrations of α-actinin, which transiently crosslinks actin filaments, and phalloidin, which stabilizes filamentous actin and increases its persistence length. We show that crosslinking and stabilization can act both synergistically and antagonistically to tune the network resistance to nonlinear straining. For example, phalloidin stabilization leads to enhanced elastic response and reduced dissipation at large strains and timescales, while the initial microscale force response is reduced compared to networks without phalloidin. Moreover, we find that stabilization switches this initial response from that of stress stiffening to softening despite the increased filament stiffness that phalloidin confers. Finally, we show that both crosslinking and stabilization are necessary to elicit these emergent features, while the effect of stabilization on networks without crosslinkers is much more subdued. We suggest that these intriguing mechanical properties arise from the competition and cooperation between filament connectivity, bundling, and rigidification, shedding light on how ABPs with distinct roles can act in concert to mediate diverse mechanical properties of the cytoskeleton and bio-inspired polymeric materials.
Theories of structural racism and sexism build from an assumption that members of privileged groups react negatively when non-privileged identities link to an agenda for change. We directly test that assumption with three online experiments administered to national samples of white men in the United States. Respondents evaluate web pages of (fictitious) civic organizations displaying agendas that could undermine race and gender hierarchies. We find that in each experiment, respondents are much more likely to disapprove of the organizational identity of the civic organizations if they are evaluating an organization that indicates it is a "Black Alliance," or a "Women's Alliance," rather than simply an "Alliance." Disapproval of the organizational identity, in turn, differentiates respondents in terms of their levels of support for the organization and its goals. Results across the three experiments are strikingly similar, ref lecting the shared micro-level assumption in different macro-level theories.
(1) Background: Secure employment has been recognized as a social determinant of health for people living with HIV (PLHIV), but limited research has been conducted to understand the employment needs and vocational decision-making process of those who are employed. The purpose of this study is to examine the applicability of the client-focused considering-work model to assess the employment outcomes and employment decision-making phases of a sample of employed PLHIV. (2) Methods: This study analyzed data of 244 employed PLHIV who completed National Working Positive Coalition’s Employment Needs Survey which included a 20-item Considering Work Scale-Employed version (CWS-Employed) and a single-item Classification of Employment Status Scale (CESS). Factor analysis was used to evaluate the CWS-Employed. Chi-square tests of homogeneity of proportions were conducted to assess the domain-specific needs of individuals in each phase of employment decision-making. (3) Results: Our findings revealed high rates of insecure employment and diverse vocational service needs among research participants. Additionally, the CWS-Employed accurately predicted 71% of the self-reported classification of phases of employment decision-making. (4) Conclusions: When investigating the role of employment as a social determinant of health, more research is needed to better understand the vocational needs and outcomes of PLHIV who are working. Improving the measurement of the phases of employment decision-making is needed to better identify appropriate vocational interventions that can lead to improved employment and related health outcomes for this population.
Social justice pedagogy in psychology requires keen attention to diversity, equity and inclusion in the content and process of teaching and learning. The contributions to this special issue address both ‘what we teach' and ‘how we teach’ psychology through recommendations for instructor preparation and practices, an expansion of concepts and methods, practical projects and activities, and curricular modifications. Importantly, the contributions raise our consciousness about the harms of oppression and marginalization in the field of psychology and offer us a path toward liberatory pedagogy.
Rich behavioral and neurobiological evidence suggests cognitive and neural overlap in how quantitatively comparable dimensions such as quantity, time, and space are processed in humans and animals. While magnitude domains such as physical magnitude, time, and space represent information that can be quantitatively compared (4 “is half of” 8), they also represent information that can be organized ordinally (1→2→3→4). Recent evidence suggests that the common representations seen across physical magnitude, time, and space domains in humans may be due to their common ordinal features rather than their common quantitative features, as these common representations appear to extend beyond magnitude domains to include learned orders. In this review, we bring together separate lines of research on multiple ordinal domains including magnitude-based and learned orders in animals to explore the extent to which there is support for a common cognitive process underlying ordinal processing. Animals show similarities in performance patterns across natural quantitatively comparable ordered domains (physical magnitude, time, space, dominance) and learned orders (acquired through transitive inference or simultaneous chaining). Additionally, they show transfer and interference across tasks within and between ordinal domains that support the theory of a common ordinal representation across domains. This review provides some support for the development of a unified theory of ordinality and suggests areas for future research to better characterize the extent to which there are commonalities in cognitive processing of ordinal information generally.
Recent research suggests experiencing community at work (i.e., perceiving a sense of community [SOC] and a sense of community responsibility [SOC-R]) is important for employee and organizational outcomes, however, we know very little about how these constructs operate in human resource management contexts. This study peers into the strategic human resource management "black box," which is an organizational setting where psychological and social variables are believed to influence employee perceptions in ways that impact their individual functioning, and subsequently improve organizational outcomes. Specifically, the study tests hypotheses regarding the relationship between high-involvement work climate (i.e., a human resource context), psychological need satisfaction, SOC, SOC-R, organizational identification, and organizational citizenship behaviors, in an attempt to theoretically ground, and empirically test, if experiences of community matter in the human resource management "black box." Data from 312 employees across multiple organizations were analyzed using partial least squares structural equation modeling, and the findings reveal that experiences of community likely play an important role in the strategic human resource black box. The findings highlight that human resource practitioners, and scholars at the intersection of community psychology and human resource management, should consider further evaluation and action around experiences of community at work. Such a focus may help to create and build more socially sustainable organizational contexts for employees where they can thrive while organizations attempt to achieve collective goals.
Background Initiation of an immune response requires activation of one or more naïve T cells. Each naïve T cell has a unique T cell receptor, and these cells traffic through the blood and lymphatic vasculatures, visiting each of the ~500 lymph nodes in search of matching antigen. If a match is made, then the naïve T cell activates and proliferates. This process is potentially rate-limiting, given the few naive T cells capable of recognizing tumor antigen and the random nature of their entry into each lymph node. We propose that stochastic nature of this process affects the probability of T cell activation and may contribute to the poor response to ICB therapy seen in most patients. Methods Here, we use multiscale computational modeling to identify potential reasons for clinical failure of immune checkpoint therapies and develop strategies for improving naïve T cell activation and tumor killing. The model provides a mechanistic framework for optimizing cancer immunotherapy and developing testable solutions to unleash anti-tumor immune responses for more patients with cancer. Results The results show that tumor antigen production rate is a critical parameter, and that patients with low tumor antigen production rate need additional treatment to enhance antigen level and improve immune checkpoint inhibition therapy. Conclusions The co-localization of antigen with appropriate naive T cells is a critical step in immune activation, and affects the anti-tumor response in the context of immune checkpoint therapy.
Introduction: Instructors assign grades to communicate to students how well they are learning the course content. However, students and instructors are often displeased with the process and outcome of grading. Statement of the Problem: We contend that conventional grading inadvertently detracts from student learning and simultaneously replicates systems of oppression in academia. We discuss Labor-Based Grading Contracts (LBGCs) as an alternative to conventional grading. Literature Review: We review the conceptual and empirical literature on LBGCs as an alternative method of assessing student work and extend its application to psychology and neuroscience courses. Teaching Implications: We present recommendations for implementing LBGCs and address common concerns instructors have about this approach. We also make a call for more research on LBGCs in psychology and neuroscience teaching and learning. Conclusion: LBGCs represent a promising shift in the purpose and approach to assessing student work and learning by centering laboring to learn and developing skills. LBGCs also create a more equitable grading structure for all students.
The claim that ‘Buddha was Born in Nepal’ is pervasive in contemporary discourses about Nepali national identity. This article focuses on the ways in which the claim to Buddha’s birthplace is deployed by some Nepalis living beyond Nepal as both a means of maintaining a connection to Nepal as a diasporic homeland and as a means of building their own online celebrity. In particular, I analyse how the claim is communicated online by three Nepali YouTubers (Lex Limbu, James Shrestha, and Sagar Tamang), whose videos embed the claim to Buddha’s birthplace within recognizable genres, memes, and narratives that are part of the Internet’s shared culture. I argue that the makers of these videos are not only reaffirming their own sense of connection to Nepal as their diasporic homeland, but are also building their own personal brands by linking their own reputations as digital microcelebrities with the Buddha’s global name recognition. Through this case study, I aim to theorize how microcelebrity can be a form of practicing citizenship at a distance within the context of a digital diaspora.
A close examination of the new Netflix series LUPIN reveals that, behind this fast moving, action packed, and entertaining mystery is a larger sociocultural commentary on the current state of race relations in France, and on how the state’s colorblindness and social cohesion are but an illusion. Through a series of encounters with systemic racism, the protagonist demonstrates his ability to navigate within the limits of an inescapable universalist model, wielding the invisibilization of migrant and descendent communities to his advantage. Via almost magical sleight of hand, artful disguise, and cunning elusion of the authorities, he exposes the French Republic’s blind spots and invites a more careful consideration of the deeper social tensions beyond his “Now you see me, now you don’t” maneuvers.
In this article, I examine the phenomenological methodology at work in Fanon's revision of the body schema. I argue that he implicitly utilizes a methodology I call standpoint phenomenology and show how this methodology emphasizes experiences that are not “universal” but specific to certain social groups in order to uncover shared ontological structures of experience. Fanon's work illustrates two key theses of standpoint phenomenology: (1) the thesis of situated phenomenology and (2) the thesis of inverted phenomenological privilege. I also draw a deep connection between classical and standpoint phenomenology by showing that it is the phenomenological analysis of breakdown experiences (e.g., corporeal malediction) that enables a standpoint approach to phenomenology. This breakdown methodology is explicitly developed by Heidegger and utilized implicitly by Merleau‐Ponty. If I am right, standpoint phenomenology is both a natural development of and a considerable advance on the traditional methodology. This article, then, provides a better understanding of Fanon's place in the phenomenological tradition and, more broadly, makes explicit a new methodology for advancing phenomenological research.
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1,436 members
Nicholas Tymvios
  • Department of Civil and Environmental Engineering
Andrea R. Halpern
  • Department of Psychology
David W. Evans
  • Department of Psychology
Regina Paxton Gazes
  • Department of Psychology and Program in Animal Behavior
Jack Gallimore
  • Department of Physics and Astronomy
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John Bravman
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