Functional analysis of RF2a, a rice transcription factor

RF2a is a bZIP transcription factor that regulates expression of the promoter of rice tungro bacilliform bad-navirus. RF2a is predicted to include three domains that contribute to its function. The results of transient assays with mutants of RF2a from which one or more domains were removed demonstrated that the acidic domain was essential for the activation of gene expression, although the proline-rich and glutamine-rich domains each played a role in this function. Studies using fusion proteins of different functional domains of RF2a with the 2C7 synthetic zinc finger DNA-binding domain showed that the acidic region is a relatively strong activation domain, the function of which is dependent on the context in which the domain is placed. Data from transgenic plants further supported the conclusion that the acidic domain was important for maintaining the biological function of RF2a. RF2a and TBP (TATA-binding protein) synergistically activate transcription in vitro (Zhu, Q., Ordiz, M. I., Dabi, T., Beachy, R. N., and Lamb, C. (2002) Plant Cell 14, 795-803). In vitro and in vivo assays showed that RF2a interacts with TBP through the glutamine-rich domain but not the acidic domain. Functional analysis of such interactions indicates that the acidic domain activates transcription through mechanisms other than via the direct recruitment of TBP.Fil: Dai, Shunhong. Chinese Academy of Sciences; República de China. Donald Danforth Plant Science Center; Estados UnidosFil: Petruccelli, Silvana. Donald Danforth Plant Science Center; Estados Unidos. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Ordiz, Maria Isabel. Donald Danforth Plant Science Center; Estados UnidosFil: Zhang, Zhihong. Donald Danforth Plant Science Center; Estados UnidosFil: Chen, Shouyi. Chinese Academy of Sciences; República de ChinaFil: Beachy, Roger N.. Donald Danforth Plant Science Center; Estados Unido

Determination of astrophysical 12N(p,g)13O reaction rate from the 2H(12N, 13O)n reaction and its astrophysical implications

The evolution of massive stars with very low-metallicities depends critically on the amount of CNO nuclides which they produce. The $^{12}$N($p$,\,$\gamma$)$^{13}$O reaction is an important branching point in the rap-processes, which are believed to be alternative paths to the slow 3$\alpha$ process for producing CNO seed nuclei and thus could change the fate of massive stars. In the present work, the angular distribution of the $^2$H($^{12}$N,\,$^{13}$O)$n$ proton transfer reaction at $E_{\mathrm{c.m.}}$ = 8.4 MeV has been measured for the first time. Based on the Johnson-Soper approach, the square of the asymptotic normalization coefficient (ANC) for the virtual decay of $^{13}$O$_\mathrm{g.s.}$ $\rightarrow$ $^{12}$N + $p$ was extracted to be 3.92 $\pm$ 1.47 fm$^{-1}$ from the measured angular distribution and utilized to compute the direct component in the $^{12}$N($p$,\,$\gamma$)$^{13}$O reaction. The direct astrophysical S-factor at zero energy was then found to be 0.39 $\pm$ 0.15 keV b. By considering the direct capture into the ground state of $^{13}$O, the resonant capture via the first excited state of $^{13}$O and their interference, we determined the total astrophysical S-factors and rates of the $^{12}$N($p$,\,$\gamma$)$^{13}$O reaction. The new rate is two orders of magnitude slower than that from the REACLIB compilation. Our reaction network calculations with the present rate imply that $^{12}$N($p,\,\gamma$)$^{13}$O will only compete successfully with the $\beta^+$ decay of $^{12}$N at higher ($\sim$two orders of magnitude) densities than initially predicted.Comment: 8 figures, 2 tables, Submitted to Physical Review

Formal planning and the reshaping of public sector professional work

This paper deals with the ‘managerialization’ of public sector professional work. Specifically, it will focus on the role of formal planning practices (as expressed in strategic planning, project management and budgeting practices) in changing public sector professional work. Planning and accounting are at the heart of public sector reforms, responding to a logic of having public service professionals transparent on what they do, on how they pursue their goals, and accountable on the use of resources and on results. Thus planning and accounting practices have been transferred from private sector management models to public, professional organizations. Yet public sector professional organizations can be conceived as a pluralistic setting characterized by diffuse power, fragmented objectives and knowledgebased and are deeply embedded in public administration regulatory logics: how can management models deriving from private, hierarchical firms be applied to the specificities and complexities of public, pluralistic settings? What is the specific meaning of formal planning practices in such complex contexts? Based on a qualitative, single case study design, this paper will show how the planning system (in its manifestation of strategic planning, project management and budgeting) applied in a public hospital apparently ‘fails’ when its deliberate role of serving as a tool for decisions is considered. Yet it is widely in use and widely accepted by professionals as well. Conclusions on the value of formal planning when other emergent roles are taken into account will be discussed

Amino Acid Deprivation Promotes Tumor Angiogenesis through the GCN2/ATF4 Pathway

AbstractAs tumors continue to grow and exceed their blood supply, nutrients become limited leading to deficiencies in amino acids (AAD), glucose (GD), and oxygen (hypoxia). These alterations result in significant changes in gene expression. While tumors have been shown to overcome the stress associated with GD or hypoxia by stimulating vascular endothelial growth factor (VEGF)-mediated angiogenesis, the role of AAD in tumor angiogenesis remains to be elucidated. We found that in human tumors, the expression of the general control non-derepressible 2 (GCN2, an AAD sensor) kinase is elevated at both protein and mRNA levels. In vitro studies revealed that VEGF expression is universally induced by AAD treatment in all five cell lines tested (five of five). This is in contrast to two other angiogenesis mediators interleukin-6 (two of five) and fibroblast growth factor 2 (two of five) that have a more restricted expression. Suppressing GCN2 expression significantly decreased AAD-induced VEGF expression. Silencing activating transcription factor 4 (ATF4), a downstream transcription factor of the GCN2 signaling pathway, is also associated with strong inhibition of AAD-induced VEGF expression. PKR-like kinase, the key player in GD-induced unfolded protein response is not involved in this process. In vivo xenograft tumor studies in nonobese diabetic/severe combined immunodeficient mice confirmed that knockdown of GCN2 in tumor cells retards tumor growth and decreases tumor blood vessel density. Our results reveal that the GCN2/ATF4 pathway promotes tumor growth and angiogenesis through AAD-mediated VEGF expression and, thus, is a potential target in cancer therapy

Federated adaptive asynchronous clustering algorithm for Wireless Mesh Networks

It is a challenge to generate an accurate machine learning model in a distributed network due to the increased concern in data privacy and high cost in gathering all raw data. This paper presents an adaptive asynchronous distributed clustering algorithm for agents in wireless network to learn the global models, while the privacy is protected. Moreover, the communication cost and clustering quality can be adaptively balanced. The proposed clustering algorithm does not require the number of clusters to be pre-defined. To improve the accuracy of the global model, we propose a bounding boxes based method to fully utilize the shape information of clusters. In addition, we consider different knowledge levels of agent and different requirements about the global model. In experiments on randomly generated network topologies, we demonstrate that methods which do more extensive clustering in each cycle, and which exchange descriptions of cluster shape and density instead of just centroids and data counts, achieve more consistent clustering, in significantly shorter elapsed time. We also show that the proposed methods can learn the same number of clusters as the ground truth when clusters are well separated from each other

Challenges and opportunities for classroom-based formative assessment and AI: a perspective article

The integration of artificial intelligence (AI) into educational contexts may give rise to both positive and negative ramifications for teachers’ uses of formative assessment within their classrooms. Drawing on our diverse experiences as academics, researchers, psychometricians, teachers, and teacher educators specializing in formative assessment, we examine the pedagogical practices in which teachers provide feedback, facilitate peer- and self-assessments, and support students’ learning, and discuss how existing challenges to each of these may be affected by applications of AI. Firstly, we overview the challenges in the practice of formative assessment independently of the influence of AI. Moreover, based on the authors’ varied experience in formative assessment, we discuss the opportunities that AI brings to address the challenges in formative assessment as well as the new challenges introduced by the application of AI in formative assessment. Finally, we argue for the ongoing importance of self-regulated learning and a renewed emphasis on critical thinking for more effective implementation of formative assessment in this new AI-driven digital age