Ana Mendieta, the Iowa Years: A Critical Study, 1969 through 1977

This dissertation investigates the artistic development of Ana Mendieta (born Cuba, 1948; died United States, 1985) from 1969 to 1977 when she lived in Iowa City, attended the University of Iowa, worked as an art teacher, and established herself as an artist. Mendieta is known for her early performance pieces and earth-body sculptures. From the late 1980s her work has been increasingly included in the contexts of feminist art history, performance, photography, work in nature, body art, self-representation, Cuban art, and transcultural identity. Collected by major museums throughout the United States, her work has begun to be included in surveys of world art. Her approach to earth-body art differed significantly from the new forms of conceptual art of the 1960s and early 1970s. By 1974 the artist had begun to produce ephemeral body-earth pieces in Iowa and Mexico that endowed nature with a human form, personifying it and evoking nature\u27s lifecycle. That work evolved from both painting and performance-oriented work that layered multiple references, with sources as diverse as her autobiography, everyday life, transcultural myths, Catholic subjects, and Western and non-Western art and archaeology. This study begins with Mendieta\u27s exile from Cuba and relocation in Iowa, then examines her evolution as a graduate student in painting (1969–1972), a Multimedia student (1972–1977), and an elementary art school teacher (1973–1975). Mendieta. developed during a period of intense collaboration between the university\u27s Multimedia area and the Center for New Performing Art, two unique programs that encouraged interdisciplinary, experimental performance work. In contextualizing that innovative period, I investigate the artist\u27s learning environment and studio practice. I also examine works that have not yet been written about, elaborate the circumstances of their creation, identify the sites and the assistance the artist had in making or performing them, incorporate her written sketchbook notations for them, and relate the substance of her comments regarding intentions for specific pieces. This study incorporates oral histories from previous instructors, colleagues, friends, and acquaintances and discusses the artist\u27s responses in her work to well-known visiting artists such as Robert Wilson, Vito Acconci, and Scott Burden, who performed and lectured at the university. Mendieta\u27s early and middle production has not been examined in the literature within the larger artistic milieu at the university. This study remedies this omission and presents a contextual reading of the artist\u27s work, thereby locating her practice within contemporary art history wherein performance, body work, and earth art were key expressive modes

Catalina Parra : In Retrospect

Herzberg investigates the cultural contexts of Parra's career, examining the origin of her work in collage and influences from the photomontage and Pop traditions. Christ looks into the relation of word and image elaborated by Parra in relation to her father's poetry. Biographical notes. 51 bibl. ref

Streptococcus gordonii type I lipoteichoic acid contributes to surface protein biogenesis

Lipoteichoic acid (LTA) is an abundant polymer of the Gram-positive bacterial cell envelope and is essential for many species. Whereas the exact function of LTA has not been elucidated, loss of LTA in some species affects hydrophobicity, biofilm formation, and cell division. Using a viable LTA-deficient strain of the human oral commensal Streptococcus gordonii, we demonstrated that LTA plays an important role in surface protein presentation. Cell wall fractions derived from the wild-type and LTA-deficient strains of S. gordonii were analyzed using label-free mass spectroscopy. Comparisons showed that the abundances of many proteins differed, including (i) SspA, SspB, and S. gordonii 0707 (SGO_0707) (biofilm formation); (ii) FtsE (cell division); (iii) Pbp1a and Pbp2a (cell wall biosynthesis and remodeling); and (iv) DegP (envelope stress response). These changes in cell surface protein presentation appear to explain our observations of altered cell envelope homeostasis, biofilm formation, and adhesion to eukaryotic cells, without affecting binding and coaggregation with other bacterial species, and provide insight into the phenotypes revealed by the loss of LTA in other species of Gram-positive bacteria. We also characterized the chemical structure of the LTA expressed by S. gordonii Similarly to Streptococcus suis, S. gordonii produced a complex type I LTA, decorated with multiple d-alanylations and glycosylations. Hence, the S. gordonii LTA appears to orchestrate expression and presentation of cell surface-associated proteins and functions.IMPORTANCE Discovered over a half-century ago, lipoteichoic acid (LTA) is an abundant polymer found on the surface of Gram-positive bacteria. Although LTA is essential for the survival of many Gram-positive species, knowledge of how LTA contributes to bacterial physiology has remained elusive. Recently, LTA-deficient strains have been generated in some Gram-positive species, including the human oral commensal Streptococcus gordonii The significance of our research is that we utilized an LTA-deficient strain of S. gordonii to address why LTA is physiologically important to Gram-positive bacteria. We demonstrate that in S. gordonii, LTA plays an important role in the presentation of many cell surface-associated proteins, contributing to cell envelope homeostasis, cell-to-cell interactions in biofilms, and adhesion to eukaryotic cells. These data may broadly reflect a physiological role of LTA in Gram-positive bacteria

Streptococcus gordonii type I lipoteichoic acid contributes to surface protein biogenesis

Lipoteichoic acid (LTA) is an abundant polymer of the Gram-positive bacterial cell envelope and is essential for many species. Whereas the exact function of LTA has not been elucidated, loss of LTA in some species affects hydrophobicity, biofilm formation, and cell division. Using a viable LTA-deficient strain of the human oral commensal Streptococcus gordonii, we demonstrated that LTA plays an important role in surface protein presentation. Cell wall fractions derived from the wild-type and LTA-deficient strains of S. gordonii were analyzed using label-free mass spectroscopy. Comparisons showed that the abundances of many proteins differed, including (i) SspA, SspB, and S. gordonii 0707 (SGO_0707) (biofilm formation); (ii) FtsE (cell division); (iii) Pbp1a and Pbp2a (cell wall biosynthesis and remodeling); and (iv) DegP (envelope stress response). These changes in cell surface protein presentation appear to explain our observations of altered cell envelope homeostasis, biofilm formation, and adhesion to eukaryotic cells, without affecting binding and coaggregation with other bacterial species, and provide insight into the phenotypes revealed by the loss of LTA in other species of Gram-positive bacteria. We also characterized the chemical structure of the LTA expressed by S. gordonii Similarly to Streptococcus suis, S. gordonii produced a complex type I LTA, decorated with multiple d-alanylations and glycosylations. Hence, the S. gordonii LTA appears to orchestrate expression and presentation of cell surface-associated proteins and functions.IMPORTANCE Discovered over a half-century ago, lipoteichoic acid (LTA) is an abundant polymer found on the surface of Gram-positive bacteria. Although LTA is essential for the survival of many Gram-positive species, knowledge of how LTA contributes to bacterial physiology has remained elusive. Recently, LTA-deficient strains have been generated in some Gram-positive species, including the human oral commensal Streptococcus gordonii The significance of our research is that we utilized an LTA-deficient strain of S. gordonii to address why LTA is physiologically important to Gram-positive bacteria. We demonstrate that in S. gordonii, LTA plays an important role in the presentation of many cell surface-associated proteins, contributing to cell envelope homeostasis, cell-to-cell interactions in biofilms, and adhesion to eukaryotic cells. These data may broadly reflect a physiological role of LTA in Gram-positive bacteria

The Decade Show : Frameworks of Identity in the 1980s

The authors examine American artistic practices in the 1980s, emphasizing the histories and work of Asian, Latin, African and Native Americans, women and gays, whose voices have traditionally been suppressed by white male middleclass domination. Includes references to ethnocentrism, deconstruction, democracy, activism, the environment, homelessness, AIDS, video and performance art. Also includes a chronology of the 1980s, and brief biographical notes. Circa 200 bibl. ref

Atom-at-a-time laser resonance ionization spectroscopy of nobelium

International audienceOptical spectroscopy of a primordial isotope has traditionally formed the basis for understanding the atomic structure of an element. Such studies have been conducted for most elements1 and theoretical modelling can be performed to high precision2, 3, taking into account relativistic effects that scale approximately as the square of the atomic number. However, for the transfermium elements (those with atomic numbers greater than 100), the atomic structure is experimentally unknown. These radioactive elements are produced in nuclear fusion reactions at rates of only a few atoms per second at most and must be studied immediately following their production4, which has so far precluded their optical spectroscopy. Here we report laser resonance ionization spectroscopy of nobelium (No; atomic number 102) in single-atom-at-a-time quantities, in which we identify the ground-state transition 1S0 1P1. By combining this result with data from an observed Rydberg series, we obtain an upper limit for the ionization potential of nobelium. These accurate results from direct laser excitations of outer-shell electrons cannot be achieved using state-of-the-art relativistic many-body calculations5, 6, 7, 8 that include quantum electrodynamic effects, owing to large uncertainties in the modelled transition energies of the complex systems under consideration. Our work opens the door to high-precision measurements of various atomic and nuclear properties of elements heavier than nobelium, and motivates future theoretical work

Superheavy Element Flerovium (Element 114) Is a Volatile Metal

The electron shell structure of superheavy elements, i.e., elements with atomic number Z ≥ 104, is influenced by strong relativistic effects caused by the high Z. Early atomic calculations on element 112 (copernicium, Cn) and element 114 (flerovium, Fl) having closed and quasi-closed electron shell configurations of 6d107s2 and 6d107s27p1/22, respectively, predicted them to be noble-gas-like due to very strong relativistic effects on the 7s and 7p1/2 valence orbitals. Recent fully relativistic calculations studying Cn and Fl in different environments suggest them to be less reactive compared to their lighter homologues in the groups, but still exhibiting a metallic character. Experimental gas–solid chromatography studies on Cn have, indeed, revealed a metal–metal bond formation with Au. In contrast to this, for Fl, the formation of a weak bond upon physisorption on a Au surface was inferred from first experiments. Here, we report on a gas–solid chromatography study of the adsorption of Fl on a Au surface. Fl was produced in the nuclear fusion reaction 244Pu(48Ca, 3–4n)288,289Fl and was isolated in-flight from the primary 48Ca beam in a physical recoil separator. The adsorption behavior of Fl, its nuclear α-decay product Cn, their lighter homologues in groups 14 and 12, i.e., Pb and Hg, and the noble gas Rn were studied simultaneously by isothermal gas chromatography and thermochromatography. Two Fl atoms were detected. They adsorbed on a Au surface at room temperature in the first, isothermal part, but not as readily as Pb and Hg. The observed adsorption behavior of Fl points to a higher inertness compared to its nearest homologue in the group, Pb. However, the measured lower limit for the adsorption enthalpy of Fl on a Au surface points to the formation of a metal–metal bond of Fl with Au. Fl is the least reactive element in the group, but still a metal