scholarly journals Dental ontogeny in the most primitive bony fish Lophosteus reveals the developmental relationship between teeth and dermal odontodes

2020 ◽  
Author(s):  
Donglei Chen ◽  
Henning Blom ◽  
Sophie Sanchez ◽  
Paul Tafforeau ◽  
Tiiu Märss ◽  
...  
Keyword(s):  
Bony Fish ◽  
Ossification Center ◽  
Developmental Relationships ◽  
Adult Morphology ◽  
Developmental Relationship ◽  
Bony Plate ◽  
Dental Ontogeny ◽  
Synchrotron Microtomography

AbstractOntogenetic data obtained by synchrotron microtomography of a marginal jawbone of Lophosteus superbus (Late Silurian, 422 Million years old), the phylogenetically basalmost stem osteichthyan, reveal developmental relationships between teeth and ornament that are not obvious from the adult morphology. The earliest odontodes are two longitudinal founder ridges formed at the ossification center. Subsequent odontodes that are added lingually to the ridges turn into conical teeth and undergo cyclic replacement, while those added labially achieve a stellate appearance. The stellate odontodes deposited directly on the bony plate are aligned with the alternate files of the teeth. Successive odontodes overgrowing the labial tooth rows become tooth-like and the replacement teeth near to them are ornament-like. We propose that teeth and ornament are modifications of a single odontode system regulated and differentiated by the oral and dermal signals; signal cross-communication between the two domains can occur around the oral-dermal boundary.

scholarly journals The developmental relationship between teeth and dermal odontodes in the most primitive bony fish Lophosteus

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Donglei Chen ◽  
Henning Blom ◽  
Sophie Sanchez ◽  
Paul Tafforeau ◽  
Tiiu Märss ◽  
...  
Keyword(s):  
Bony Fish ◽  
Ossification Center ◽  
Single System ◽  
Adult Morphology ◽  
Developmental Relationship ◽  
Bony Plate ◽  
Ontogenetic Trajectory ◽  
Sequential Addition ◽  
Synchrotron Microtomography

The ontogenetic trajectory of a marginal jawbone of Lophosteus superbus (Late Silurian, 422 Million years old), the phylogenetically most basal stem osteichthyan, visualized by synchrotron microtomography, reveals a developmental relationship between teeth and dermal odontodes that is not evident from the adult morphology. The earliest odontodes are two longitudinal founder ridges formed at the ossification center. Subsequent odontodes that are added lingually to the ridges turn into conical teeth and undergo cyclic replacement, while those added labially achieve a stellate appearance. Stellate odontodes deposited directly on the bony plate are aligned with the alternate files of teeth, whereas new tooth positions are inserted into the files of sequential addition when a gap appears. Successive teeth and overgrowing odontodes show hybrid morphologies around the oral-dermal boundary, suggesting signal cross-communication. We propose that teeth and dermal odontodes are modifications of a single system, regulated and differentiated by the oral and dermal epithelia.

Unpacking the Microdynamics of Multiplex Peer Developmental Relationships: A Mutuality Perspective

2021 ◽  
pp. 014920632110484
Author(s):  
Jessica R. Methot ◽  
Michael S. Cole
Keyword(s):  
Leadership Development ◽  
Psychosocial Support ◽  
Development Program ◽  
Social Processes ◽  
Developmental Relationships ◽  
Career Support ◽  
Network Characteristics ◽  
Developmental Relationship ◽  
Active Interest ◽  
Over Time

Peer developmental relationships—informal arrangements between pairs of individuals who take an active interest in and concerted action to advance one another's careers—offer a valuable alternative to formal mentorships. Despite recognition that peer developmental relationships have the potential to jointly provide career and psychosocial support (i.e., multiplexity) and that relationships embodying multiple support dimensions are indispensable, a paucity of work investigates what factors contribute to their dynamics and persistence over time. To address this issue, we integrate the microfoundations of network dynamics and mutuality perspectives to identify why and when social processes—specifically, reciprocity, trust, and trust asymmetry—operate to form, strengthen, or maintain multiplex peer developmental relationships. To test our hypotheses, we collected three waves of data over one-and-a-half years from a cohort of individuals participating in a leadership development program. Using variations of the Quadradic Assignment Procedure (QAP) to investigate dyad-level dynamics, our results generally suggest that (over and above demographics and network characteristics) the provision of psychosocial support relatively early in the peer-to-peer relationship is likely to evolve into a more complex, high-quality relationship comprised of both psychosocial support and career support (i.e., a multiplex peer developmental relationship). Perhaps more importantly, the social processes capturing mutuality further increased the likelihood that multiplex developmental relationships would develop and persist over time. Our results demonstrate that mutuality is both generative and resolute in nurturing multiplex developmental relationships.

scholarly journals Author response: The developmental relationship between teeth and dermal odontodes in the most primitive bony fish Lophosteus

2020 ◽  
Author(s):  
Donglei Chen ◽  
Henning Blom ◽  
Sophie Sanchez ◽  
Paul Tafforeau ◽  
Tiiu Märss ◽  
...  
Keyword(s):  
Bony Fish ◽  
Author Response ◽  
Developmental Relationship

Developmental Relationship Programs: An Empirical Study Of The Impact Of Peer-Mentoring Programs

2013 ◽  
Vol 7 (1) ◽  
pp. 31 ◽  
Author(s):  
Siamack Shojai ◽  
William J. Davis ◽  
Patricia S. Root
Keyword(s):  
Ordinary Least Squares ◽  
Public University ◽  
Intervention Programs ◽  
Mentoring Programs ◽  
Medium Size ◽  
Developmental Relationships ◽  
Paired Samples ◽  
Developmental Relationship ◽  
Performance Gains ◽  
The Impact

This paper provides an empirical analysis of the impact and effectiveness of developmental relationships provided through academic intervention programs at a medium-size masters level public university in the Northeastern United States. The programs curriculum follows the Model of Strategic Learnings four pillars of learning and is administered to students with diverse interventional needs. This paper presents a brief review of the literature about effective developmental relationship programs (mentoring and coaching) in higher education. Then, Ordinary Least Squares regressions, as well as paired samples t-tests, are used to test the impact of programs offered through developmental relationships to students with varying academic deficiencies. The immediate, as well as longer-term, impact and sustainability of students enhanced performance is statistically examined. The paper concludes that students who fully take advantage of developmental relationships benefit the most and sustain their higher level of performance beyond the immediate post one-time intervention period. However, in the absence of additional intervention, the academic performance gains seem to subside and flatten out.

Apophysites – Revue de la littérature et ­nouvelles directions

2014 ◽  
Vol 62 (3) ◽  
Keyword(s):  
Scientific Evidence ◽  
Ossification Center ◽  
Health Staff ◽  
Optimal Management ◽  
Long Term Effect ◽  
High Incidence ◽  
Youth Athlete ◽  
Pathology Education ◽  
Main Factor

Apophysitis are part of the growth-related diseases within youth athlete population. Despite their high incidence within this growing cohort, many doubts remain. The physiopathology is still debated. Initially, the fragmentation of the ossification center was seen as the main factor of the disease. For few years, this theory has been questioned due to consistent signs of tendon suffering. Apophysitis may have some negative long-term effect on a sporting career. There is currently poor scientific evidence on the optimal management and no treatment has been widely accepted. Prevention remains the most powerful intervention in this particular pathology. Education of the athlete’s sporting entourage (family, coaches and health staff) and the athlete himself is necessary to act quickly and adapt the training load to decrease mechanical stress on the suffering apophysis.

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