Mathematical models for somite formation

Somitogenesis is the process of division of the anterior–posterior vertebrate embryonic axis into similar morphological units known as somites. These segments generate the prepattern which guides formation of the vertebrae, ribs and other associated features of the body trunk. In this work, we review and discuss a series of mathematical models which account for different stages of somite formation. We begin by presenting current experimental information and mechanisms explaining somite formation, highlighting features which will be included in the models. For each model we outline the mathematical basis, show results of numerical simulations, discuss their successes and shortcomings and avenues for future exploration. We conclude with a brief discussion of the state of modeling in the field and current challenges which need to be overcome in order to further our understanding in this area

Mathematical models for somite formation

Somitogenesis is the process of division of the anterior–posterior vertebrate embryonic axis into similar morphological units known as somites. These segments generate the prepattern which guides formation of the vertebrae, ribs and other associated features of the body trunk. In this work, we review and discuss a series of mathematical models which account for different stages of somite formation. We begin by presenting current experimental information and mechanisms explaining somite formation, highlighting features which will be included in the models. For each model we outline the mathematical basis, show results of numerical simulations, discuss their successes and shortcomings and avenues for future exploration. We conclude with a brief discussion of the state of modeling in the field and current challenges which need to be overcome in order to further our understanding in this area

Proficient brain for optimal performance: the MAP model perspective

Background. The main goal of the present study was to explore theta and alpha event-related desynchronization/synchronization (ERD/ERS) activity during shooting performance. We adopted the idiosyncratic framework of the multi-action plan (MAP) model to investigate different processing modes underpinning four types of performance. In particular, we were interested in examining the neural activity associated with optimal-automated (Type 1) and optimal-controlled (Type 2) performances. Methods. Ten elite shooters (6 male and 4 female) with extensive international experience participated in the study. ERD/ERS analysis was used to investigate cortical dynamics during performance. A 4 × 3 (performance types × time) repeated measures analysis of variance was performed to test the differences among the four types of performance during the three seconds preceding the shots for theta, low alpha, and high alpha frequency bands. The dependent variables were the ERD/ERS percentages in each frequency band (i.e., theta, low alpha, high alpha) for each electrode site across the scalp. This analysis was conducted on 120 shots for each participant in three different frequency bands and the individual data were then averaged. Results. We found ERS to be mainly associated with optimal-automatic performance, in agreement with the “neural efficiency hypothesis.” We also observed more ERD as related to optimal-controlled performance in conditions of “neural adaptability” and proficient use of cortical resources. Discussion. These findings are congruent with the MAP conceptualization of four performance states, in which unique psychophysiological states underlie distinct performance-related experiences. From an applied point of view, our findings suggest that the MAP model can be used as a framework to develop performance enhancement strategies based on cognitive and neurofeedback technique

Storytelling and/as resilience

Storytelling implications have been under-explored in LIS. Storytelling involves a teller, an audience, and a story that emerges in the dynamic exchange--laughter, gasps, suspenseful silence--so that each storytelling moment creates a unique version of the story. This panel expands pedagogical and theoretical understandings of the value of storytelling as tradition, practice, and means of cultivating resilience. This panel brings together experts in storytelling, resilience, and storytelling as resilience to demonstrate that storytelling deserves conceptual prominence in LIS. The panel format will be focused on a question-and-answer response, asking each panelist to introduce their work briefly and then engage the questions including: Why is storytelling important to LIS, and what makes it a worthwhile strategy? How has the LIS tradition of storytelling contributed to community resilience? What stories are missing, underrepresented, devalued, suppressed, oppressed, or written out of LIS storytelling? How might LIS education benefit from taking seriously the relationships between teller, audience, and story in both practice and theory? Dr. Nicole Cooke’s work on storytelling, from autoethnography to fake news, brings together the urgent necessity of developing greater LIS cultural competence in services to diverse populations with the potential power of storytelling for positive social change. Her research engages the importance of telling untold stories, including those that challenge racism as status quo, and bringing everyday lived experiences of racism to light in order to change LIS professionals and support the resilience of those minoritized by the field. Dr. Cooke also engages storytelling as a tool for understanding information behavior and enacting social justice. Her recent book, Fake News and Alternative Facts: Information Literacy in a Post-Truth Era (ALA Editions. 2018), examines how some stories operate as information threat and suggests paths toward resistance and resilience for information professionals. Her teaching engages storytelling as pedagogy in teaching cultural competence and, as Augusta Baker Chair, leads an annual community-focused storytelling festival celebrating Augusta Baker’s legacy as a leading storyteller in the history of LIS. Dr. Janice Del Negro is a nationally acclaimed storyteller and a professor at the School of Information Studies at Dominican University in River Forest, Illinois, where she teaches storytelling and related graduate and doctoral courses. Her research interests coalesce around the examination of storytelling in three arenas: the history of library storytelling, the contemporary storytelling revival, and the library story told through narrative. Dr. Del Negro, as both insider and observer in these communities, has written extensively on these topics; she collaborated with Dr. Ellin Greene on the fourth edition of the classic storytelling textbook, Storytelling: Art &Technique (2010, fully revised fifth edition forthcoming in Fall 2021). Recently Dr. Del Negro’s research interests focus on an examination of storytelling during COVID, in both the contemporary storytelling community for adults and in youth services programming in libraries. How do pandemic considerations alter the delivery of oral narrative programming? What is the relationship between storytelling, storytellers, and resilience? How do story deliverers understand the relationship between storytelling and technology? Does the delivery mechanism alter the presentation and reception of stories? The surprisingly effective move from face-to-face to virtual storytelling created new connections between tellers and listeners as a strong example of the power of story as well as the resilience of storytellers, librarians, and listeners. Dr. Beth Patin’s work on resilience draws on concepts of storytelling during extreme events and crises. “We know ourselves only through stories” (Justice, 2018 p. 34). Narratives tell the stories of a community and after a disaster or crisis, they preserve the experiences of the community for those in the future. Recently, in response to the protests about police brutality and systemic racism in the United States, many information organizations are examining their historical relationship with racism and how this has in turn affected their collections and whose voices we amplify in our libraries and through storytelling. Who gets to be deemed literary? Who does not? And how does that impact students who are told that their stories do not count? Through the exploration of storytelling and narrative after disasters and trauma-related experiences, Dr. Patin examines how we might use digital humanities tools to help preserve, amplify, and foster engagement with the next generation, especially for minoritized communities whose stories largely have been untold. Doctoral Candidate Curtis Tenney teaches digital storytelling, and their research on libraries, LGBTQ+ issues, and community resilience is grounded in a research agenda inspired by the contemporary importance of exploring contentious phenomena by interrogating documents and exploring what might be learned from the experiences of people involved. This goal is focused to inquire: What stories do public storytelling programming tell? Their dissertation work titled, LGBTQ+ Representation in Public Library Programming: Investigating Drag Storytime Events, investigates drag storytime event documentation and the experiences of public librarians and drag performers involved in drag storytime events. This research goal seeks to explore how LGBTQ+ representation is documented and how public librarians and drag performers plan drag storytime events and how information behavior is enacted, engaging storytelling as pedagogy through early experiences teaching digital storytelling and storytelling for information professionals. In this panel, Curtis will draw from preliminary research findings and teaching experiences to share perspectives of LIS work intersections of storytelling and resilience. Panel organizer Dr. Kate McDowell’s work on storytelling engages fundamental LIS concepts to argue that storytelling provides a critical lens for understanding collective information. Her work asserts that story is a fundamental but overlooked form of information, and that rigorous analysis of storytelling processes and practices demonstrate that the default conceptualization of information as an individual experience excludes a wide range of collective information practices. Based on over a decade of teaching storytelling, running the student-focused Storytelling Festival at Illinois, and four years of co-teaching data storytelling, her research spans theoretical definitions and practical applications of storytelling. In this panel, she will argue that igniting LIS research on story as a fundamental information form has implications for understanding collective information experiences, how information and story contribute to belief and belonging, and story as misinformation that threatens societal resilience

A clock and wavefront mechanism for somite formation

Somitogenesis, the sequential formation of a periodic pattern along the antero-posterior axis of vertebrate embryos, is one of the most obvious examples of the segmental patterning processes that take place during embryogenesis and also one of the major unresolved events in developmental biology. In this article, we develop a mathematical formulation of a new version of the Clock and Wavefront model proposed by Pourquié and co-workers (Dubrulle, J., McGrew, M.J., Pourquié, O., 2001. FGF signalling controls somite boundary position and regulates segmentation clock control of spatiotemporal Hox gene activation. Cell 106, 219–232). Dynamic expression of FGF8 in the presomitic mesoderm constitutes the wavefront of determination which sweeps along the body axis interacting as it moves with the segmentation clock to gate cells into somites. We also show that the model can mimic the anomalies formed when progression of the wavefront is disturbed and make some experimental predictions that can be used to test the hypotheses underlying the model

Automated data analysis to rapidly derive and communicate ecological insights from satellite-tag data: A case study of reintroduced red kites

Analysis of satellite-telemetry data mostly occurs long after it has been collected, due to the time and effort needed to collate and interpret such material. Such delayed reporting does reduce the usefulness of such data for nature conservation when timely information about animal movements is required. To counter this problem we present a novel approach which combines automated analysis of satellite-telemetry data with rapid communication of insights derived from such data. A relatively simple algorithm (comprising speed of movement and turning angle calculated from fixes), allowed instantaneous detection of excursions away from settlement areas and automated calculation of home ranges on the remaining data Automating the detection of both excursions and home range calculations enabled us to disseminate ecological insights from satellite-tag data instantaneously through a dedicated web portal to inform conservationists and wider audiences. We recommend automated analysis, interpretation and communication of satellite tag and other ecological data to advance nature conservation research and practice

From segment to somite: segmentation to epithelialization analyzed within quantitative frameworks

One of the most visually striking patterns in the early developing embryo is somite segmentation. Somites form as repeated, periodic structures in pairs along nearly the entire caudal vertebrate axis. The morphological process involves short- and long-range signals that drive cell rearrangements and cell shaping to create discrete, epithelialized segments. Key to developing novel strategies to prevent somite birth defects that involve axial bone and skeletal muscle development is understanding how the molecular choreography is coordinated across multiple spatial scales and in a repeating temporal manner. Mathematical models have emerged as useful tools to integrate spatiotemporal data and simulate model mechanisms to provide unique insights into somite pattern formation. In this short review, we present two quantitative frameworks that address the morphogenesis from segment to somite and discuss recent data of segmentation and epithelialization

Maintaining the Power Output of An Existing Coal Plant with the Addition of CO 2 Capture: Retrofits Options With Gas Turbine Combined Cycle Plants

AbstractIt is likely that a significant number of existing pulverised coal-fired power plants will be retrofitted with post-combustion capture as part of a global rollout of carbon capture and storage. Previous studies have demonstrated that the energy penalty for post-combustion carbon dioxide (CO2) capture can be greatly minimised by effective integration of the capture system with the power cycle. Nevertheless, the power output of the site is, in most cases, reduced and the volume of electricity sales would drop. For other plants, the existing steam cycle may not be able to be integrated effectively for steam extraction, or space and access around/to the steam cycle may be impossible. As an alternative to steam extraction, it is possible to retrofit existing coal plants with a gas turbine combined cycle plant (CCGT) to maintain, or even increase, the site power output. The gas turbine can be integrated to the existing coal plant in various ways to supply all the heat, or a fraction of the heat, and the power required for the capture systems. An important consideration is whether carbon emissions from both, the combined cycle and the retrofitted coal plant are captured, or from the latter only.This paper examines these different options for carbon capture retrofits to existing coal plant and presents a novel configuration with the sequential combustion of gas turbine flue gas in the existing coal boiler while capturing carbon emissions from the combustion of coal and natural gas

X-ray and optical monitoring of the peculiar source 4U 1700+24/V934 Her

(Abridged) We report on ASCA and BeppoSAX observations of the X-ray source 4U 1700+24 and on (quasi-)simultaneous spectroscopy of its optical counterpart, V934 Her, from the Loiano 1.5-meter telescope. Archival ROSAT and RXTE data as well as the RXTE ASM light curve of 4U 1700+24 are also analyzed along with a 1985 EXOSAT pointing. The optical spectra are typical of a M2 III star; a revised distance to the object of ~400 pc is inferred. While these spectra do not show either any change between the two epochs or any peculiar feature, the X-ray spectra reveal a complex and long-term variable shape, with a clear soft excess. The X-ray spectral properties of the source are best described by a thermal Comptonization spectrum plus a soft energy(<1 keV) excess, which can be modeled with a blackbody emission with kT_BB ~ 1 keV; the latter component is not detected at the lowest source flux levels. The ratio between the two components varies substantially with the source flux. The X-ray emission from the object appears to become harder as its luminosity increases, and the RXTE data acquired during an outburst occurred during Fall 1997 display a hard tail detected up to 100 keV. Apart from erratic shot-noise variability on timescales of tens to thousands of seconds, no significant pulsations or QPOs are found from the timing analysis of the X-ray light curves. With the new distance determination, the 2-10 keV X-ray luminosity range spanned in the considered observations lies between ~2x10^32 and ~1x10^34 erg/s. All this allows us to suggest a scenario consisting of a wide binary system in which a neutron star accretes matter from the wind of an M giant.Comment: 14 pages, 5 figures, to be published on Astronomy & Astrophysics, Main Journa

A multimodal analysis of facework strategies in a corpus of charity ads on British television

The aim of this article is to carry out a qualitative multimodal analysis of the codification of verbal and non-verbal politeness strategies in a sub-corpus of five charity commercials aired on British television. Brown and Levinson's (1987) verbal politeness strategies are taken as a starting point together with a detailed analysis of facework that is realized through paralinguistic and extralinguistic modes of communication (Kress and van Leeuwen, 2006 and Machin, 2010). In what we have identified as the problem phase of the commercial, our analysis has revealed that advertisers deliberately attempt to create threats to the viewer's positive and negative face by making him/her feel responsible for the plight of others. In all five ads, through multi-scene montage, positive and off-record politeness strategies are enacted involving vivid case stories, demand images, sad music and serious extradiegetic voices. These strategies also help convey the idea that the suffering of others might also affect viewers at some point in their lives and thus strengthen the bond between the characters depicted in the ads and those watching them. During the solution phase, in which images, melodies and voice-overs become more upbeat, negative politeness strategies are used to soften the actual request to donate while positive politeness strategies are employed to appeal to the presupposed solidarity of the viewers. Our analysis points to the need to carry out further research on the interplay between verbal and non-verbal communication, especially in the field of politeness studies.Pennock-Speck, B.; Saz Rubio, MMD. (2013). A multimodal analysis of facework strategies in a corpus of charity ads on British television. Journal of Pragmatics. 49(1):38-56. doi:10.1016/j.pragma.2012.12.010S385649