Analysis of the maize cytokinin receptor Zea mays Histidine Kinase 1 function using Saccharomyces cerevisiae

Cytokinins (CK) regulate a diverse assortment of processes in plants, including cellular division, biosynthesis of chloroplasts, and differentiation within root and apical meristems. Response to CK is regulated through a two-component signal transduction system consisting of a receptor and a response regulator. Two-component signaling systems are highly conserved in bacteria, fungi and plants and allow organisms to sense and respond to external and internal stimuli. Our analysis of the semi-dominant, leaf patterning maize mutant Hairy Sheath Frayed1 (Hsf1) identified the maize CK receptor Zea mays Histidine Kinase1 (ZmHK1) as the underlying gene. The Hsf1 phenotype is marked by the outgrowth of proximal leaf tissue (sheath, auricle and ligule) in the distal leaf blade, reduced leaf size, and increased leaf pubescence. Missense mutations in the CK binding domain of ZmHK1 increase ligand binding affinity, resulting in CK hypersignaling and giving rise to altered leaf patterning in Hsf1. We are using a two-component signaling assay in Saccharomyces cerevisiae to understand the relationship between these amino acid changes and altered ZmHK1 activity. We have assayed the three independent Hsf1 alleles (Hsf1-1595, Hsf1-1603, and Hsf1-AEWL) using the yeast system and found some signal in the absence of added CK. We are making additional targeted amino acid changes near the CK binding domain in ZmHK1 to determine which residues are critical for ligand recognition, binding and signaling. Our current results will be presented

Characterization of targeted missense Zea mays Histidine Kinase1 mutations in Saccharomyces cerevisiae reveal residues important for signaling activity

Cytokinins (CKs) regulate a diverse assortment of processes in plants, including cellular division, vasculature differentiation, and meristem maintenance. CK perception and response is regulated through a two-component signal transduction system, which are highly conserved in bacteria, fungi and plants and allow organisms to sense and respond to diverse stimuli. Our analysis of the maize mutant Hairy Sheath Frayed1 (Hsf1) identified the CK receptor Zea mays Histidine-Kinase1 (ZmHK1) as the underlying gene which linked CK signaling to control of leaf growth and patterning for the first time. Three missense mutations in the CK-binding domain of ZmHK1 define all known Hsf1 alleles. Each causes increased ligand binding affinity and hypersignaling, producing altered leaf morphology in Hsf1 mutants. Using a Saccharomyces cerevisiae reporter strain containing the heterologous ZmHK1 gene, we tested the ability of 18 ZmHK1 missense mutations targeted to the CK-binding domain to promote Hsf1-like CK hypersignaling. Yeast harboring these mutant ZmHK1 genes were grown with and without CKs to analyze their ability to bind and signal. Some mutations led to Hsf1-like hypersignaling, while others produced no change in activity. These targeted amino acid changes are providing insight as to which residues are critical for ligand recognition, binding, and signaling

Mysticism in Science Fiction: Science Fiction As a Vehicle for Mystical Thought and Experience

Literature Review: Much of the current available scholarship on science fiction and its engagement with the spiritual centers about religious tropes in science fiction, such as aliens as deities, gnosticism, the “personhood” of machines, and apocalypse. James F. McGrath in his book Theology and Science Fiction argues that science fiction often intersects the spiritual, and suggests that these religious tropes in science fiction are actually an engagement with common theological questions. The trope of gods as aliens corresponds to the theological question of “what merits our worship, or at least our reverence?”; gnosticism responds to the question of “whether comfortable truths are preferable to a pleasant lie”; and so on (McGrath 27, 36). Scholarship on mysticism, on the other hand, typically engages with the history of mysticism and the common forms of mystical prac- tices, as enumerated in texts such as Mysticism: Its History and Challenge by Bruno Borchert and Mysticism by Evelyn Underhill. This thesis connects these two realms of scholarship by en- gaging with the mystical, rather than the theological aspects of science fiction, and investigating why science fiction is an appropriate vehicle for mystical thought and action. Thesis Statement: The reading of science fiction literatures, especially the work of Stanislaw Lem and Philip K. Dick, may be understood as simulations aimed at inducing metacognition, and through this metacognition, enlightenment. Through common science fiction tropes such as simulation, the divine invasion, and the breakdown of reality, science fiction novels thus present themselves as simulations which induce inquiry into the nature of the self and the nature of reality, and in effect, rearticulate ancient contemplative tropes through the language of a relatively modern literary genre. Theoretical Framework: The framework for this thesis is informed by an understanding of mysticism according to authors and scholars such as Evelyn Underhill, Richard Doyle, and Jeffrey J. Kripal. The framework is also based in an understanding of rhetoric that informs the analysis of how and why science fiction is conducive to mystical thought and experience. Project Description: Science fiction is a genre steeped in mystical tradition. Many themes in science fiction, such as the theme of the unknowable, incomprehensible alien, as well as the theme of alternate realities/dystopia, can be read as literary reworking of mysticism, which is conglomerate of be- liefs and practices that attempts to engage with a higher power or hidden truth. Using a mystical framework informed by scholars such as Evelyn Underhill, Jeffrey J. Kripal, Richard Doyle, and Joshua DiCaglio, science fiction novels can be read and analyzed as not only informed by mystical ideas, but as texts which function as simulations of the mystically experience in of themselves. In particular, the novels of Philip K. Dick and Stanislaw Lem rework ancient contemplative tropes concerning the nature of reality and of the self through the modern language of science fiction using its tropes of simulation, the divine invasion, and the breakdown of reality

The crisis-Image: rites of passage in American independent cinema (Coppola, Jarmusch and Van Sant 1994-2004)

My aim in this thesis is to examine a corpus of six films as loose representations or investigations of various rites of passage: adolescence, death and life-choice. In order to do this, I will draw upon a synthesis of theoretical texts: primarily the film-philosophy of Gilles Deleuze (1925-1995) (in particular his theory of crisis, cinematic time and thought) and the anthropological writings of Arnold van Gennep (1973-1957) and Victor Turner (1920-1983) on rites of passage. More specifically, I will focus on the concept of liminality as a state in which one is ‘betwixt and between’ (Turner 1995: 95) categories. Any rite of passage, as we will see, can be separated out into a tripartite structure: separation, liminality and re-integration. The films discussed in this thesis centre on the stage of liminality as one of inherent ambiguity, metamorphosis and transition. More often than not, the passage is not completed so the liminal stage is never resolved. As I will demonstrate in the following chapters, film is the ultimate medium for presenting crisis and liminality because its very essence as an art form is being as change. Through close analysis of the six films to be discussed, I will demonstrate that contemporary American Independent cinema has produced some of the prime examples of film as the medium of crisis, liminality, evolution, mutation or becoming-other. At this stage, I will outline the corpus of films to be examined in this thesis and then elaborate on the main theoretical framework I will employ in order to draw out the specificity and complexity of this kind of cinema

Long-range multipartite entanglement close to a first order quantum phase transition

We provide insight in the quantum correlations structure present in strongly correlated systems beyond the standard framework of bipartite entanglement. To this aim we first exploit rotationally invariant states as a test bed to detect genuine tripartite entanglement beyond the nearest-neighbor in spin-1/2 models. Then we construct in a closed analytical form a family of entanglement witnesses which provides a sufficient condition to determine if a state of a many-body system formed by an arbitrary number of spin-1/2 particles possesses genuine tripartite entanglement, independently of the details of the model. We illustrate our method by analyzing in detail the anisotropic XXZ spin chain close to its phase transitions, where we demonstrate the presence of long range multipartite entanglement near the critical point and the breaking of the symmetries associated to the quantum phase transition.Comment: 6 pages, 3 figures, RevTeX 4, the abstract was changed and the manuscript was extended including the contents of the previous appendix

The Role of Environment on the Formation of Early-Type Galaxies

(Abridged) We present a detailed study of the stellar populations of a volume-limited sample of early-type galaxies from SDSS, across a range of environments -- defined as the mass of the host dark matter halo. The stellar populations are explored through the SDSS spectra, via projection onto a set of two spectral vectors determined from Principal Component Analysis. We find the velocity dispersion of the galaxy to be the main driver behind the different star formation histories of early-type galaxies. However, environmental effects are seen to play a role (although minor). Galaxies populating the lowest mass halos have stellar populations on average ~1Gyr younger than the rest of the sample. The fraction of galaxies with small amounts of recent star formation is also seen to be truncated when occupying halos more massive than 3E13Msun. The sample is split into satellite and central galaxies for a further analysis of environment. Satellites are younger than central galaxies of the same stellar mass. The younger satellite galaxies in 6E12Msun halos have stellar populations consistent with the central galaxies found in the lowest mass halos of our sample (i.e. 1E12Msun). This result is indicative of galaxies in lower mass halos being accreted into larger halos.Comment: 11 pages, 10 figures. Accepted for publication in MNRA

What Can We Do to Improve Peer Review in NLP?

Peer review is our best tool for judging the quality of conference submissions, but it is becoming increasingly spurious. We argue that a part of the problem is that the reviewers and area chairs face a poorly defined task forcing apples-to-oranges comparisons. There are several potential ways forward, but the key difficulty is creating the incentives and mechanisms for their consistent implementation in the NLP community.Comment: To appear at Findings of EMNL

BAICE Thematic Forum:Challenging deficit discourses in international education and development

Research and policy in international education has o en been framed in terms of a deficit discourse. For instance, policy debates on women’s literacy and education have begun by positioning women as a group who need to ‘catch up’ on certain skills in order to become more active in development. Rather than recognising the skills and knowledge that participants already have and prac se in their everyday lives, researchers who adopt this deficit perspective on learning and education may find that the research agenda and questions will already be shaped to a large extent by the providers’/ policy makers’ standpoint. This BAICE Thematic Forum aimed to deepen understanding around how deficit discourses have shaped the questions and objectives of international educational research. As well as deconstructing and gaining greater knowledge into why and how these dominant deficit discourses have influenced the research agenda, we also set out to investigate and propose alternative conceptual models through two linked seminars. The seminars were intended to explore and challenge dominant deficit discourses that have shaped the way researchers/policy makers look at specific groups in development and thematic policy areas