Conflict outcome in male green swordtail fish dyads (Xiphophorus helleri): Interaction of body size, prior dominance/subordination experience and prior residency

The relative contribution of asymmetries in prior experience, size, and prior residency to the determination of dyadic dominance between unacquainted individuals was examined using pairs of green swordtail fish, Xiphophorus helleri. Four types of encounters were staged between an intruder and a smaller resident: (1) both had experienced prior victory; (2) both had experienced prior defeat; (3) the intruder had experienced prior victory and the resident prior defeat; and (4) the intruder had experienced prior defeat and the resident prior victory. In a fifth condition in which two intruders met, one was a prior subordinate and the other a prior dominant smaller in size than its opponent. In all these encounters, the superiority in lateral surface of one fish varied between 0 to 30% over that of its opponent. Results showed that (1) when size differences between contestants were within the range of 0-10% and there was an asymmetry in prior social experience, conflicts were essentially resolved according to prior experience with prior winners systematically defeating prior losers; (2) prior residency of 3 hours was an advantage only when both opponents had experienced prior defeat before meeting and when size asymmetries were small (e.g. <20%). It was not an advantage between prior winners or between a prior winner and a prior loser; (3) when large size asymmetries existed (e.g. 20-30%), size uniquely determined dominance outcome and nullified other advantages or disadvantages due to prior social experience and prior residency; and (4) at intermediate levels of size asymmetries (e.g. 10-20%), size partially cancelled any advantage due to a prior victory, and gradually beacme the most important factor in accounting for victories

Outcome of dyadic conflict in male green swordtail fish, Xiphophorus helleri: effects of body size and prior dominance

The relative contribution of prior experience and of size asymmetries to the determination of dyadic dominance between unfamiliar individuals was examined using pairs of green swordtail fish, Xiphophorus helleri. Three experiments were conducted to assess the extent to which superiority in size could override potential handicaps resulting from prior experience. These results indicated that prior experience accounted for dyadic dominance when the size advantage of a previously subordinate over a previously dominant opponent was less than 25 mm2. However, as the lateral surface of the subordinate fish increased, neither previous experience nor size differences clearly accounted for the outcome of dyadic conflict. Even when the size advantage of subordinate opponents was in the 126-150 mm2 range, size differences did not adequately explain the outcome. In conflicts between large previously subordinate and smaller dominant fish, there was evidence for an inverse linear relation between the effects of size and the likelihood of establishing dyadic dominance. In general, males with prior experience as subordinates had to be at least 40% larger than a previously dominant fish to win a significant proportion of conflicts. These results indicate that prior agonistic experience and body size effects can be additive when at the advantage of one opponent. These factors can also cancel each other out when in opposition, at least when size differences are not extreme. The results also confirm the main effect of both factors as well as their interaction in the determination of conflict outcomes for X. helleri

DISCRETE ADAPTIVE RESPONSES TO MEK INHIBITOR IN SUBPOPULATIONS OF TRIPLE NEGATIVE BREAST CANCER

Triple-negative breast cancer (TNBC) is characterized by genomic heterogeneity and high risk of relapse. Recent studies have demonstrated that breast cancers can contain a spectrum of epithelial and mesenchymal phenotypes. We identified epithelial (POS) and mesenchymal (NEG) subpopulations in a triple negative breast cancer cell line that have similar coding sequences, but unique enrichment of the epigenetic activators H3K27ac and BRD4. We show that localization of these epigenetic activators correlates with the expression of epithelial transcription factors TP63 and ELF3 in epithelial cells, and ZEB1 and TWIST1 in mesenchymal cells. Currently, there are no targeted therapies available for the treatment of triple negative breast cancer. However, overexpression of EGFR, KRAS, or BRAF occurs in approximately 30% of TNBC, suggesting that inhibiting the MAPK signaling pathway may be an effective therapy for TNBC. Acute treatment with the MEK inhibitor trametinib induced distinct transcriptional responses in epithelial and mesenchymal subpopulations. ChIP-Seq analysis of H3K27ac and BRD4 binding revealed epigenetic remodeling in response to trametinib treatment, especially at binding sites for AP-1 in NEG cells and epithelial-specific ETS transcription factors in POS cells. Chronic treatment with trametinib induced the emergence of trametinib resistant POS cells, but not NEG cells. In trametinib resistant POS cells, we observe increased expression of the Gi-coupled chemokine receptor CXCR7, and its cognate ligand adrenomedullin, as well as increased expression of KRAS. ChIP-Seq analysis revealed enrichment of H3K27ac and BRD4 at the CXCR promoter and enhancer, indicating epigenetic remodeling induces transcriptional activation. siRNA knockdown of CXCR7 and KRAS demonstrate these genes are essential for the proliferation of trametinib resistant cells, and reveals that epigenetic remodeling at the CXCR7 locus may be a mechanism for drug resistance.Doctor of Philosoph

The Engineering Challenges of Designing and Manufacturing a Tensegrity Cup Stand

Progressing from a simple idea into a fully developed product is one of the main goals of any engineer. Through Haley Barbour Center for Manufacturing Excellence’s capstone program, the team was tasked with realizing a tensegrity cup stand. The tensegrity structure consists of a top and a bottom of some form only supporting itself by tension. The team had to research the concept, create an initial design, create a prototype of the product, improve the design after the prototype’s mistakes, apply lean principles to improve the manufacturing efficiency, and analyze all the economic impacts of the engineering decisions. In the end, a well-polished product and process was achieved while still providing a positive-profit business model. The capstone process taught the whole team an extensive amount of real-world engineering challenges as well as the contributions needed to manufacture a product

SCALES: An Original Model to Diagnose Soil Erosion Hazard and Assess the Impact of Climate Change on Its Evolution

International audienceSoil erosion is a major and growing cause of soil deterioration in many European countries. The main issue is that we must no longer consider soil as a renewable natural resource. Whatever the scale of intervention, the territorial structures need to have spatially spread information in order to overcome or prevent soil erosion. In this regard, maps of erosion hazard constitute essential documents. Our goal was multiple when we developed SCALES model. Firstly, the point was to prove that it was reasonable to foresee a regional scale model and map while we have detailed local scale data. Then, we wanted to limit the model applicability to the European oceanic areas which are marked by a mutual pedoclimatic situation and a territorial dividing into agricultural parcels. Besides, our idea was to consider the soil erosion hazard within these parcels which are area sources: assuming that in this geographic context the erosion is more controlled by agricultural units rather than the environment where they dwell. We eventually had to take into consideration the weight of agricultural practices through their temporality when we assessed this hazard. 250 After we proved SCALES was operational in Calvados, we contemplated editing the model in order to achieve an assessment of the erosion hazard within intra-annual time scales. SCALES progressive nature allows us to consider this model as spatially and temporally dynamic. However, the required investment for produce the data in order to decline the model at the monthly and seasonal scales does not allow us to establish a mapping of the soil erosion hazard on a regional level. Consequently, this fine temporal approach must be held for sectors with strong environmental stake. If SCALES can be used in a predictive approach, its structuring and its modularity also give opportunities within a prospective framework. It is what we did, in Basse-Normandie, concerning the topic of the impact of the climate change on the evolution of the cultivated soils susceptibility to erosion by water. In average year at horizon 2100, the results of this new application show that the levels of soil erosion hazard would be comparable with those currently obtained within the one year framework rainy of which the probability of return is once every 4 years. One would thus witness a reinforcement of the soil erosion hazard in average year. We now wish to look further into the prospective application of SCALES starting from the studies which present, in comparable areas, the scenarios of agricultural practices evolution in a near future and a future distance. Our first results and the aim which we propose are altogether in the spirit of the recommendations of the GIEC (2007b) and the European Environment Agency which reminds us the necessity to develop tools to assess the impact of climate change on soils

Prefatory Note

Each of the articles in Draftings in Management deals with an important contemporary management issue. Although our students may take positions that can be (and are being) debated, we are certain readers will agree that their work is thoughtful and provocative, and that it makes a contribution to the public discussion

Toward a Resilient Global Society: Air, Sea Level, Earthquakes, and Weather

Society’s progress along the four corners of prepare, absorb, respond and adapt resilience square is uneven, in spite of our understanding of the foundational science and a growing sense that urgent action is needed. The resilience vignettes describe the meaning and impact of current and near‐term change in four major domains: human health impacts from air pollution, coastal inundation from sea‐level rise, damaging earthquakes in populated areas, and impacts from extreme precipitation. Given our understanding of the scientific principles, societal action, from preparation to adaption, will be critical in minimizing the negative impacts of change. The unprecedented rates of change in today’s Earth system argue for urgent action in support of a resilient global society.Key PointsUnprecedented rates of change in the Earth system argue for more urgent action in support of a resilient global societyExperts describe the meaning and impact of current and near‐term change in four major domainsWe take an ensemble approach to highlight the similarities for actionable decision‐makingPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151889/1/eft2547_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151889/2/eft2547.pd