ABC Model Research Articles

Comparative investigation into key optoelectronic characteristics of semipolar InGaN blue laser diodes: A strategy to mitigate quantum-confine stark effect

In recent years, semipolar InGaN-based blue laser diodes (LDs) have raised indescribable appeal within solid-state lighting industry as promising alternatives for currently available polar c-plane LDs due to reduction in internal polarization field and related quantum-confined stark effect. However, any comparative study in terms of energy band gap, optical emission profile, power output (P) and forward bias response (I-V) etc. between semipolar-oriented InGaN blue LDs is inherently unattainable. This work aims to demonstrate the impact of internal polarization field on aforementioned key optoelectronic parameters of In0.17Ga0.83N/GaN double quantum well (DQW) blue LD along semipolar (101-2), (112-2), (101-1), (202-1), (303-1-), (202-1-) and (101-1-) crystal orientations by figuring out six-band k.p Hamiltonian at the brillouin zone center aided from Euler’s tensor transformation method. Three-level rate equations based LD analogous circuit model and state-space matrix are employed here to obtain P-I-V and frequency characteristics. Radiative as well as non-radiative recombination mechanisms for LD systems are portrayed by addressing modified ABC model. Our numerical investigation illustrates that best hole effective mass, optical gain, lasing power, threshold current and forward voltage can be attained from (112-2)-oriented InGaN blue LD due to insignificant presence of spontaneous plus piezoelectric (PZ) polarization charge. In addition with these, the inspection of bode plot and relevant optical power gain (dB) confirms the stability and superiority of this semipolar blue LD system for achieving high-speed visible-light communications at relatively low current densities.

Analytical models of electron leakage currents in gallium nitride-based laser diodes and light-emitting diodes.

The electrical-to-optical power conversion efficiencies of the light-emitting devices based on gallium nitride (GaN) are seriously limited by electron leakage currents due to the relatively low mobility and activation ratio of holes. However, there have been few theoretical models on the behavior of the leakage current with an increasing total current. We develop an Ohmic-law-like method to describe the transport behaviors of the systems with electron and hole currents simultaneously. Based on reasonable assumptions, the ratio of the leakage current to the total current is related to the differential resistances of the devices. Through the method, we develop analytical models of the leakage currents in GaN-based laser diodes (LDs) and light-emitting diodes (LEDs). The ratios of the leakage currents with total currents in LDs and LEDs are shown to increase, which explains the sublinear behaviors of the luminescence-current (LI) curves of the devices. The theory agrees well with the numerical simulation and experimental results in larger current ranges in comparison to the traditional ABC model. The above analytical model can be used to fast evaluate the leakage currents in GaN-based LDs and LEDs.

The limiting energy capabilities of high-power AlInGaN LEDs

The object of study in this work was the most advanced AlInGaN LEDs of the "UX : 3" design with a distributed system of reflective contacts located on the back side of the emitting chip. The current dependences of the output optical power and emission spectral characteristics, including their distribution (mapping) over the emitting surface in a wide range of operating currents up to ~ 30 A have been studied. An analysis of the near-field emission by intensity and spectrum revealed a high uniformity of the current density distribution at all levels of excitation (no current crowding). Thus, the saturation of the optical power and the quantum efficiency droop are explained by purely internal factors, which are well described by the ABC model. Keywords: AlInGaN LED, quantum efficiency, emission spectrum, near-field emission.

Gender and green IT practice - implications from the ABC model of attitude

Gender and green IT practice - implications from the ABC model of attitude

Modeling the dynamics of COVID-19 using fractal-fractional operator with a case study

This research study consists of a newly proposed Atangana–Baleanu derivative for transmission dynamics of the coronavirus (COVID-19) epidemic. Taking the advantage of non-local Atangana–Baleanu fractional-derivative approach, the dynamics of the well-known COVID-19 have been examined and analyzed with the induction of various infection phases and multiple routes of transmissions. For this purpose, an attempt is made to present a novel approach that initially formulates the proposed model using classical integer-order differential equations, followed by application of the fractal fractional derivative for obtaining the fractional COVID-19 model having arbitrary order Ψ and the fractal dimension Ξ. With this motive, some basic properties of the model that include equilibria and reproduction number are presented as well. Then, the stability of the equilibrium points is examined. Furthermore, a novel numerical method is introduced based on Adams–Bashforth fractal-fractional approach for the derivation of an iterative scheme of the fractal-fractional ABC model. This in turns, has helped us to obtained detailed graphical representation for several values of fractional and fractal orders Ψ and Ξ, respectively. In the end, graphical results and numerical simulation are presented for comprehending the impacts of the different model parameters and fractional order on the disease dynamics and the control. The outcomes of this research would provide strong theoretical insights for understanding mechanism of the infectious diseases and help the worldwide practitioners in adopting controlling strategies.

Socio-cultural barriers to the adaptation of foreign students to Russian higher education

Interest in the problem of socio-cultural adaptation of foreign students is growing due to intensification of the processes of internationalization of education, global competition of universities, and increase in the export of educational services. The purpose of the study is to analyze the types and causes of the emergence of socio-cultural barriers to adaptation of foreign students in the context of higher education in Russia; to work out recommendations for their reduction. The theoretico-methodological basis of the research is the ABC model of culture shock, phenomenological approach to the analysis of intercultural communications (ICC) in the global world. The socio-cultural barriers to the adaptation are considered through the prism of the lack of ICC resources increasing the manifestations of culture shock, and first of all—social perception. Based on the synthesis of studies by Russian and foreign authors, the article examines the causes of the formation of deficiencies in the linguistic, paralinguistic, cognitive and behavioral competencies necessary for successful socio-cultural adaptation of foreign students. The primary materials are the results of the monitoring ^Assessment of the quality of education at the Financial University» conducted by the focus group method at the Financial University in the 2020-2021 academic year. To improve the socio-cultural adaptation of foreign students to education, the authors propose telecollaboration. The conclusions and recommendations given in the article can be used in the field of education for children and adults, including additional and inclusive education (students with disabilities, migrant students, etc.).

Analytical Intervention of Remote Working Correlates on Risk Culture and Entrepreneurial Adaptability in South-South Geopolitical Zone, Nigeria: Covid-19 Perspective

This study explored the analytical intervention of remote-working correlates on risk culture and entrepreneurial adaptability in South-South geopolitical zone, Nigeria. The study adopted ex-post facto design and exploratory research design. Data were generated from entrepreneurs’ with specialty on self-development training program for hand craft skills by quantitative and qualitative methods. The study used multi-stage cluster sampling and proportionate stratified random sampling techniques. A total population of 200 and a sample size of 133 were determined using Krejcie and Morgan Table. Also, 133 copies of questionnaire were distributed to the respondents and 127 copies were completed and retrieved. The instrument was validated with reliability above 0.7 co-efficient, using Cronbach Alpha technique. The reliability coefficient analysis was attitude (α =0.912), behaviour (α=0.893), competence (α =0.894), adaptability (α=0.911) and remote working (α=0.901). Four research questions and four hypotheses were raised which were tested with KMO for the sampling adequacy and Barllet’s test for data appropriateness sphericity. The Ordinary Least Square Method (OLSM) and Partial Correlation Co-efficient were used to analyze the hypotheses of the explanatory, response and intervening variables via SPSS 25 version. From the findings, remote working correlates risk culture and entrepreneurial adaptability positively. In conclusion, attitude, behavior and competence have significant influence on entrepreneurial adaptability of self-development training program enterprise. Based on the findings and conclusion, this study contributes to the knowledge that to adapt with the storm of the covid-19 variant and working from home, risk culture measures should be streamline with the enterprise vision and mission pursuit. It could be recommended that to encourage remote working, the risk culture ABC model must be adopted and practice that will enable the enterprise to have competitive advantage. Also, risk culture and remote working should be encouraged because of the covid-19 pandemic to prevent the self-development training enterprise from bleeding. Keywords: Attitude, Behaviour, Competence, Entrepreneurial Adaptability, Remote Working, Covid-19 Pandemic DOI: 10.7176/JEP/12-34-05 Publication date: December 31 st 2021

The MADS-box gene FveSEP3 plays essential roles in flower organogenesis and fruit development in woodland strawberry

Flower and fruit development are two key steps for plant reproduction. The ABCE model for flower development has been well established in model plant species; however, the functions of ABCE genes in fruit crops are less understood. In this work, we identified an EMS mutant named R27 in woodland strawberry (Fragaria vesca), showing the conversion of petals, stamens, and carpels to sepaloid organs in a semidominant inheritance fashion. Mapping by sequencing revealed that the class E gene homolog FveSEP3 (FvH4_4g23530) possessed the causative mutation in R27 due to a G to E amino acid change in the conserved MADS domain. Additional fvesep3CR mutants generated by CRISPR/Cas9 displayed similar phenotypes to fvesep3-R27. Overexpressing wild-type or mutated FveSEP3 in Arabidopsis suggested that the mutation in R27 might cause a dominant-negative effect. Further analyses indicated that FveSEP3 physically interacted with each of the ABCE proteins in strawberry. Moreover, both R27 and fvesep3CR mutants exhibited parthenocarpic fruit growth and delayed fruit ripening. Transcriptome analysis revealed that both common and specific differentially expressed genes were identified in young fruit at 6–7 days post anthesis (DPA) of fvesep3 and pollinated wild type when compared to unpollinated wild type, especially those in the auxin pathway, a key hormone regulating fruit set in strawberry. Together, we provided compelling evidence that FveSEP3 plays predominant E functions compared to other E gene homologs in flower development and that FveSEP3 represses fruit growth in the absence of pollination and promotes fruit ripening in strawberry.

Psychosocial effects of the Covid-19 pandemic in Turkey and an investigation of rational emotional behavioral therapy within the framework of the ABC model

Pandemiler kişinin kendisine ve sevdiklerine yönelik sağlık tehditlerini de içeren birçok farklı psikososyal stres faktörü ile ilişkilidir. Pandemi sürecinde, insanların yaşamış oldukları duygusal sorunların ve enfeksiyonun yayılmasını önleyecek psikolojik faktörlerin belirlenmesi, hastalığın yayılmasını engelleyecek olan davranışların yerine getirilmesi, duygusal sıkıntıların uyumsuzlukların ve yıkıcı davranışların yönetilmesi açısından önemlidir. Bu araştırmada Türkiye’de yaşayan yetişkin bireyler üzerinde Covid-19 pandemisinin psikososyal etkilerinin incelenmesi ve akılcı duygusal davranışçı terapinin ABC modeli çerçevesinde analiz edilmesi amacıyla, nitel araştırma yöntemlerine dayalı olarak durum çalışması deseni kullanılmıştır. Araştırmanın çalışma grubunu 18 yaş üzerindeki 245 yetişkin birey oluşturmuştur. Bulgular katılımcıların %7.3’ünün sağlık güvencesi bulunmadığını ve %23.7’si karantina süresince hiç egzersiz yapmadığını, %35.5’inin gelir kaybı yaşadığını, %72.7’sinin sosyal medya kullanma davranışlarının arttığını, %89.8’inin virüsün sıkı önlemler alınmasını gerektirecek kadar tehlikeli olduğuna inandığını göstermektedir. Salgın süreci ile birlikte katılımcıların hayatlarında biyolojik, sosyolojik, psikolojik, ekonomik pek çok farklı değişimler, zorlanmalar, öğrenmeler olmuştur. Katılımcıların Covid 19’a yönelik düşünceleri de birbirinden farklılık göstermektedir. Katılımcılardan çok azı (f=24) salgına dair akılcı düşüncelere sahiptir. Katılımcıların akılcı olmayan düşünceleri, Talepkarlık (f=104), Felaketleştirme (f=84), Rahatsız olmaya katlanamama (f=66) ve Diğerlerini ve kendini derecelendirme (f=36) olmak üzere dört kategoriye ayrılmıştır. Akılcı düşüncelere sahip katılımcıların duyguları daha sağlıklı ve davranışları daha işlevselken, akılcı olmayan düşüncelere sahip katılımcıların duyguları daha sağlıksız ve davranışları da daha işlevsizdir.

Physiotherapy for large airway collapse: an ABC approach.

Large airway collapse (LAC) describes the phenomenon of excessive, abnormal, inward movement of the large airways (i.e. trachea and/or main bronchi and/or bronchus intermedius) occurring during the expiratory phase of the respiratory cycle. It is an increasingly well-recognised problem and a prevalent comorbidity in other chronic respiratory conditions (e.g. COPD and asthma). LAC is associated with pervasive respiratory features such as a barking cough, exertional dyspnoea and an increased propensity to lower respiratory tract infection. These symptoms are unpleasant, and patients are often limited in their daily life and their function. The pathophysiology of this condition impairs airway clearance and can cause breathlessness and exercise intolerance, due to a loss of airway patency during expiratory flow. Dysfunctional adaptations to breathing and coughing may further amplify symptoms.This article provides, for the first time, clinically focused physiotherapeutic intervention advice based on our understanding of the pathophysiology of LAC, to support conservative management. It uses the available evidence from LAC, transferable evidence from other conditions and knowledge based on clinical experience. It proposes a practical “ABC model” to ensure physiotherapy assessment and treatments are centred around optimising three key clinical areas: Airways, including airway clearance and cough; Breathing, including breathlessness and breathing pattern; and Capacity for exercise, including an assessment of functional exercise ability.

Role of Newtonian heating on a Maxwell fluid via special functions: memory impact of local and nonlocal kernels

The impact of Newtonian heating on a time-dependent fractional magnetohydrodynamic (MHD) Maxwell fluid over an unbounded upright plate is investigated. The equations for heat, mass and momentum are established in terms of Caputo (C), Caputo–Fabrizio (CF) and Atangana–Baleanu (ABC) fractional derivatives. The solutions are evaluated by employing Laplace transforms. The change in the momentum profile due to variability in the values of parameters is graphically illustrated for all three C, CF and ABC models. The ABC model has proficiently revealed a memory effect.

Heat and Mass Transfer Impact on Differential Type Nanofluid with Carbon Nanotubes: A Study of Fractional Order System

This paper is an analysis of flow of MHD CNTs of second grade nano-fluid under the influence of first order chemical reaction, suction, thermal generation and magnetic field. The fluid is flowing through a porous medium. For the study of heat and mass transfer, we applied the newly introduced differential operators to model such flow. The equations for heat, mass and momentum are established in the terms of Caputo (C), Caputo–Fabrizio (CF) and Atangana–Baleanu in Caputo sense (ABC) fractional derivatives. This shows the novelty of this work. The equations for heat, mass and momentum are established in the terms of Caputo (C), Caputo–Fabrizio (CF) and Atangana–Baleanu in Caputo sense (ABC) fractional derivatives. The solutions are evaluated by employing Laplace transform and inversion algorithm. The flow in momentum profile due to variability in the values of parameters are graphically illustrated among C, CF and ABC models. It is concluded that fluid velocity showed decreasing behavior for χ, P, ℏ2, Mo, Pr, ℵ and Sc while it showed increasing behavior for Gr, Gm, κ and Ao. Moreover, ABC fractional operator presents larger memory effect than C and CF fractional operators.

Differential Effects of Iberdomide Versus Revlimid on Leukocyte Trafficking, Immune Activation and DLBCL Tumor Cell Killing

Introduction: Revlimid (Rev), binds to CRL4 CRBN E3 ligase leading to recruitment and proteasomal degradation of transcription factors Aiolos and Ikaros. This inhibits proliferation of malignant B cells and stimulates activity of T, NK and macrophage cells, thereby providing clinical activity of Rev as a single agent and in combination with CD19/CD20 antibodies in DLBCL and FL. Iberdomide (Iber), a new CELMoD with enhanced substrate degradation compared to Rev, is currently being studied in clinical trials for B-NHL and MM. Presented here is extensive in vitro and in vivo characterization of immune enhancement and antitumor effects of Iber with direct comparison to Rev.Results: In a panel of DLBCL cell lines, comprising ABC and GCB-DLBCL models, Iber degraded Aiolos/Ikaros with faster kinetics and to a greater depth than Rev, which led to enhanced antiproliferative and cytotoxic effects. Iber acted in a cell of origin independent manner, whereas Rev is preferentially active in ABC-DLBCL. To examine the molecular effects of Iber and Rev in immune cells, we performed RNAseq and proteomic based analyses on Iber and Rev treated T, NK and monocyte cell populations. These experiments revealed a complex series of immunomodulatory activities including promotion of pro-inflammatory cytokine production, activation marker expressions and migratory machinery with a trend of Iber exhibiting greater enhancements. We confirmed these findings by demonstrating that secretion of chemoattractants for T cells, NK cells and monocytes including CXCL9, 10 and 11 (10-90% increase) and CCL8 (30% increase, p<0.01) were higher in PBMCs treated with Iber compared to Rev. Additionally, functional chemotaxis assays demonstrated that Iber and Rev increased the trafficking capacity of T-cells compared to DMSO alone, with Iber demonstrating a greater increase than Rev (46% vs 21%, p<0.01). Furthermore, Iber increased the proliferative capacity of CD8+ T and NK cells compared to Rev (10 and 3.6-fold vs 4 and 2.8-fold, respectively). Functional co-culture assays with DLBCL cells showed that Iber induced NK cell mediated killing of DLBCL cells to a greater extent than Rev and each molecule enhanced ADCC with Rituximab compared to vehicle controls. Translational data from clinical trials of a related CELMoD, Avadomide, revealed significant trafficking of immune cells such a T cells, NK cells and monocytes to the tumor microenvironment (TME). To examine the effects of Rev and Iber in an in vivo DLBCL GEMM model, we developed a humanized CRBN (hCRBN) mouse capable of facilitating proteasomal degradation of target substrates upon treatment with a CELMoD. The hCRBN mouse was then crossed with the Eμ-Myc DLBCL mouse model resulting in Eμ-Myc/hCRBN progeny that then developed disease. Splenocytes were collected and transplanted to recipient hCRBN mice. The tumor cells were allowed to engraft for 5 days upon which 3 daily doses of vehicle, Rev and Iber were given prior to the mice being sacrificed. Non-transplanted hCRBN mice served as controls. Similar to human disease, DLBCL cells remodeled the myofibroblast-immune network within lymph node and the splenic tissues including activated podoplanin (PDPN)-expressing fibroblastic reticular cells (FRCs) and diminished CD8+ T cells and CD11c+ DCs within the lymphoid TMEs. Treatment with Iber resulted in significantly enhanced infiltration of DCs and notably, cytolytic granzyme B positive T cells into the TME compared to Rev or vehicle treated mice (Figure 1). Additional characterization of the immune (T cell, NK and monocyte)-stroma TME is on-going and will be presented.Conclusion: Our data demonstrate that Iber is more potent in substrate degradation and functionality in anti-proliferative activity against DLBCL cell line models and at triggering immunostimulatory activities in multiple lymphoid and myeloid populations. Additionally, we generated a humanized CRBN mouse model that revealed the ability of CELMoDs in inducing immune-rich TMEs supporting rational combination strategies with immune focused agents being explored in lymphoma such as SIRPα blockade, CAR T and CD3xCD20 bispecifics. [Display omitted] DisclosuresNakayama: Bristol Myers Squibb: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Chiu: Bristol Myers Squibb: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Narla: Bristol Myers Squibb: Current Employment. Shakya: Bristol Myers Squibb: Current Employment. Gamez: Bristol Myers Squibb: Current Employment. Hagner: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Gandhi: Bristol Myers Squibb: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company.

Design Optimization of Multi-Layer Permanent Magnet Synchronous Machines for Electric Vehicle Applications

This paper presents a comparison between two design methodologies applied to permanent magnet synchronous machines for hybrid and electric vehicles (HEVs and EVs). Both methodologies are based on 2D finite element models and coupled to a genetic algorithm to optimize complex non-linear geometries such as multi-layer permanent magnet machines. To reduce the computation duration to evaluate Induced Voltage and Iron Losses for a given electrical machine configuration, a new methodology based on geometrical symmetries and magnetic symmetries are used and is detailed. Two electromagnetic models have been developed and used in the design stage. The first model was the stepped rotor position finite element analysis called abc model which considered the spatial harmonics without any approximation of the waveform of flux linkage inside the stator, and the second model was based on a fixed rotor position called dq model, with the approximation that the waveform of flux linkage inside the stator was sinuous. These two methodologies are applied to the design of a synchronous machine for HEVs and EVs applications. Design results and performances are analyzed, and the advantages and drawbacks of each methodology are presented. It was found that the dq model is at least 5 times faster than the abc model with high precision for both the torque and induce voltage evaluation in most cases. However, it is not the case for the iron losses computation. The iron loss model based on dq model is less accurate than the abc model with a relative deviation from the abc model greater than 70% at high control angle. The choice of the electromagnetic model during the optimization process will therefore influence the geometry and the performances of the obtained electrical machine after the optimization.

Design and Verification of a Simple Approach to Brownfields Categorization

Brownfields have been the subject of research, evaluation, categorization and, of course, redevelopment for many years. The ABC(D) model (an assessment tool to identify different types of sites in terms of their potential) by the Concerted Action on Brownfield and Economic Regeneration Network (CABERNET) has been mentioned in many publications. The aim of the assessment method presented in this article is to use the basic essence of the categories in the ABC(D) model and to use our own very simple criteria. Our criteria are the result of many years of experience in the creation and management of the brownfield database. In 2017, the development potential of selected brownfields in the database of the Moravian-Silesian region (Czech Republic) was evaluated using our proposed procedure (three objective and one subjective criterion). In 2020, verification of the categories in regard to how correctly or incorrectly they were proposed was carried out. The results from this verification, including reasons for the accompanying inaccuracies, are a part of this article. We verified that the very simple evaluation procedure we proposed is functional and can be applied by database administrators continuously without the need to create complex datasets and statistical evaluations.

The Regularity of the Decrease in the Quantum Yield of Quantum-Wells LEDs at the Long-Term Current Flow from the ABC Model Position

The works on degradation of light emitting diodes (LEDs) with quantum wells (QW) were analysed. The calculation model of the relation between LED luminous flux and duration of LED current flow and current density was proposed. It allows us to forecast service life of such radiators with the pre-set electric modes and temperature. It is demonstrated that: – Reduction of quantum yield of LED with QW based on high-bandgap semiconductors with longterm flow of forward current occurs due to generation of point defects in the QW areas; – The dot defects occur as a result of interaction between hot electrons and semiconductor atoms caused by subthreshold displacement out of the lattice dots; – The dot defects create non-radiative recombination centres with particular concentration in the energy gap of a semiconductor, as a result of which intensities of recombination flows in QWs and in barriers between QWs redistribute towards the non-radiative component of the ABC model.

The relevance appraisal matrix: Evaluating others' relevance.

People seek to detect who facilitates and who impedes their goal pursuit. The resulting relevance appraisals of opportunity and threat, respectively, can strongly shape subsequent social judgment and behavior. However, important questions about the nature of relevance appraisals remain unanswered: Are relevance appraisals unidimensional or multidimensional? Are people evaluated as generally posing opportunities and/or threats, or as dynamically relevant depending on perceiver goals? We test two hypotheses. First, we propose that opportunity and threat are appraised independently, rather than as endpoints of a single dimension. If so, then others can be evaluated as (a) facilitating a goal, (b) impeding a goal, (c) both facilitating and impeding a goal, or (d) neither facilitating nor impeding a goal. Second, we hypothesize that relevance appraisals shift dynamically with perceiver goals. For example, a single person may be appraised as facilitating one's mate-seeking goal, but as neither facilitating nor impeding one's self-protection goal. In two studies, participants rated the extent to which a variety of targets (e.g., a doctor, a 5-year-old child) pose threats and opportunities to different goals. Confirmatory factor analyses support both hypotheses. We also explore relationships between the Relevance Appraisal Matrix and the stereotype content (Fiske et al., 2002) and ABC (Koch et al., 2016) models of stereotypes, finding evidence that relevance appraisals are distinct from stereotypes of group attributes. In sum, we provide a framework for understanding the structure of relevance appraisals: A central and consequential, yet dynamic and relatively understudied, aspect of social cognition. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The MADS-box gene PpPI is a key regulator of the double-flower trait in peach.

Double flower is an invaluable trait in ornamental peach, but the mechanism underlying its development remains largely unknown. Here, we report the roles of ABCE model genes in double flower development in peach. A total of nine ABCE regulatory genes, including eight MADS-box genes and one AP2/EREBP gene, were identified in the peach genome. Subcellular localization assay showed that all the ABCE proteins were localized in the nucleus. Four genes, PpAP1, PpAP3, PpSEP3, and PpPI, showed a difference in expression levels between single and double flowers. Ectopic overexpression of PpPI increased petal number in Arabidopsis, while transgenic lines overexpressing PpAP3 or PpSEP3 were morphologically similar to wild-type. Ectopic overexpression of PpAP1 resulted in a significant decrease in the number of basal leaves and caused early flowering. These results suggest that PpPI is likely crucial for double flower development in peach. In addition, double flowers have petaloid sepals and stamens, and single flower could occasionally change to be double flower by converting stamens to petals in peach, suggesting that the double-flower trait is likely to have evolved from an ancestral single-flower structure. Our results provide new insights into mechanisms underlying the double-flower trait in peach.

Theories, laws, and models in evo-devo.

Evolutionary developmental biology (evo‐devo) is the study of the evolution of developmental mechanisms. Here, I review some of the theories, models, and laws in evo‐devo, past and present. Nineteenth‐century evo‐devo was dominated by recapitulation theory and archetypes. It also gave us germ layer theory, the vertebral theory of the skull, floral organs as modified leaves, and the “inverted invertebrate” theory, among others. Newer theories and models include the frameshift theory, the genetic toolkit for development, the ABC model of flower development, the developmental hourglass, the zootype, Urbilateria, and the hox code. Some of these new theories show the influence of archetypes and recapitulation. Interestingly, recent studies support the old “primordial leaf,” “inverted invertebrate,” and “segmented head” theories. Furthermore, von Baer's first three laws may now need to be rehabilitated, and the hourglass model modified, in view of what Abzhanov has pointed out about the maternal‐zygotic transition. There are many supposed “laws” of evo‐devo but I argue that these are merely generalizations about trends in particular lineages. I argue that the “body plan” is an archetype, and is often used in such a way that it lacks any scientific meaning. Looking to the future, one challenge for evo‐devo will be to develop new theories and models to accommodate the wealth of new data from high‐throughput sequencing, including single‐cell sequencing. One step in this direction is the use of sophisticated in silico analyses, as in the “transcriptomic hourglass” models.

Expression and Functional Analyses of Nymphaea caerulea MADS-Box Genes Contribute to Clarify the Complex Flower Patterning of Water Lilies.

Nymphaeaceae are early diverging angiosperms with large flowers characterized by showy petals and stamens not clearly whorled but presenting a gradual morphological transition from the outer elements to the inner stamens. Such flower structure makes these plant species relevant for studying flower evolution. MADS-domain transcription factors are crucial components of the molecular network that controls flower development. We therefore isolated and characterized MADS-box genes from the water lily Nymphaea caerulea. RNA-seq experiments on floral buds have been performed to obtain the transcript sequences of floral organ identity MADS-box genes. Maximum Likelihood phylogenetic analyses confirmed their belonging to specific MADS-box gene subfamilies. Their expression was quantified by RT-qPCR in all floral organs at two stages of development. Protein interactions among these transcription factors were investigated by yeast-two-hybrid assays. We found especially interesting the involvement of two different AGAMOUS-like genes (NycAG1 and NycAG2) in the water lily floral components. They were therefore functionally characterized by complementing Arabidopsis ag and shp1 shp2 mutants. The expression analysis of MADS-box genes across flower development in N. caerulea described a complex scenario made of numerous genes in numerous floral components. Their expression profiles in some cases were in line with what was expected from the ABC model of flower development and its extensions, while in other cases presented new and interesting gene expression patterns, as for instance the involvement of NycAGL6 and NycFL. Although sharing a high level of sequence similarity, the two AGAMOUS-like genes NycAG1 and NycAG2 could have undergone subfunctionalization or neofunctionalization, as only one of them could partially restore the euAG function in Arabidopsis ag-3 mutants. The hereby illustrated N. caerulea MADS-box gene expression pattern might mirror the morphological transition from the outer to the inner floral organs, and the presence of transition organs such as the petaloid stamens. This study is intended to broaden knowledge on the role and evolution of floral organ identity genes and the genetic mechanisms causing biodiversity in angiosperm flowers.