Separation of Variables and the Computation of Fourier Transforms on Finite Groups, II

We present a general diagrammatic approach to the construction of efficient algorithms for computing the Fourier transform of a function on a finite group. By extending work which connects Bratteli diagrams to the construction of Fast Fourier Transform algorithms %\cite{sovi}, we make explicit use of the path algebra connection to the construction of Gel'fand-Tsetlin bases and work in the setting of quivers. We relate this framework to the construction of a {\em configuration space} derived from a Bratteli diagram. In this setting the complexity of an algorithm for computing a Fourier transform reduces to the calculation of the dimension of the associated configuration space. Our methods give improved upper bounds for computing the Fourier transform for the general linear groups over finite fields, the classical Weyl groups, and homogeneous spaces of finite groups, while also recovering the best known algorithms for the symmetric group and compact Lie groups.Comment: 53 pages, 5 appendices, 34 figure

Hearing morse, music, mountains and heart beats : a sociology of sensory knowing

We rely on our senses to make judgements and perform roles, whether these are mundane aspects of life such as road crossing, or the more specialised tasks of music-making and paediatric surgery. Taking the example of hearing, this thesis argues that it is useful to consider the senses as a form of knowledge, adopting Fredrik Barth's position that knowledges are avenues through which people actively engage with their worlds. In defining knowledge and the senses in these terms, this research is an exploratory contribution to both sensory studies and sociologies of knowledge. Based on participant observation and interviews with 92 musicians, doctors, adventurers and Morse code operators, the thesis begins by examining each epistemic community's underlying knowledge base, before exploring their learning methods and the conditions that support the development of aural acuity. It then explores the role of the senses in expert practices, illustrating their value in decision-making,particularly in critical contexts. This thesis argues that the senses are a dynamic and active form of knowledge that needs to be examined at the micro- and macro-sociological level, as well as across careers and lifespans. It illustrates how the senses are learnt, interactive, responsive and personal

Five Sided

Sada Kernodle: There are seven billion people existing on this earth. That’s seven billion unique and complex minds viewing our natural world. My work includes images of organic life with the physical world. Through this, I hope to inspire those billions of minds to create, explore, and gradually heal through the process of making art. The combination of the human mind, body, and spirit with nature in its rawest form, has the ability to create powerful art pieces. This is the new global footprint for the world. Elliecia Hall: My art is about balance and imbalance. It’s both light and dark. I take dark themes and present them through a feminine and colorful lens. Feminine things are often perceived as innocent and naive, but I’ve never felt that to be true to my experience. I use art to articulate myself more fully; to bring life to the anger in my heart as much as the joy in my soul. Dreams and nightmares have had such an effect on my life. Most of my earliest memories have been of my sleeping world. And while my world is affected so strongly by the darkness of sleep, I see the world in vibrant color, and look to paint my illustrations in the same way I see everything around me. Josh Kukowski: I am an artist with his mind in the future. I find myself obsessed with the unknown that the future holds. My work should evoke the sense of wonder and motivation that is felt when we sent the first man to space and the first man to the moon. I create scenes with visual and textual reality, so others join me, invited into the world and experience the wonder yet unknown. My work focuses on scale and the scale of humans to their creations that already is and could be in the future. I want people to view my work and find themselves swept from the pres¬ent, where many seem to be stuck, and into my future. Kaitlynn Moslen: Watercolor has been my medium of choice for years because of its ability to slowly build the scene with con¬trolled washes of color. The gossamer layers of watercolor have an enchanting effect translating the narratives I explore. Dreams often reflect my emotional state in subtle, surreal ways. I consider the symbols and incon¬gruities in my dreams and I often arrive at revelations or find solutions to problems. My dreams operate with insight at a level beyond what I have in the waking world. These are translated into my artwork through the expression of a human figure along with symbolic aspects of the natural world. This usually includes serene bodies of water, trees and foliage found in unexpected places, and docile forest animals. Sarah Walden: Ever since I was a little girl my mother inspired me in the gardens with her flowers. It is in the gardens that I found my inspiration for art. Working in the garden is inspiring to me. I want to be a part of the process that points to the path of art. Illustrative images affects the influence of my viewers. I intend to express deep sublim¬inal images to spark creativity within my viewers lives, that will encourage them to work for a better future as well. The subliminal in my work deals with human emotions and experiences. Art can be used to heal and bring people together to make a change. A few people can be a big change. The mission for my art is to inspire others, so that I may inspire the rest of the world to save itself though creativity. Though the elements of art, expression is created, transferring knowledge from the artist to the viewer. Art is more than just materiality; it is the silent language of color and form that speaks to the consciousness of the audience

Sequences in the cytoplasmic tail of SARS-CoV-2 Spike facilitate expression at the cell surface and syncytia formation.

The Spike (S) protein of SARS-CoV-2 binds ACE2 to direct fusion with host cells. S comprises a large external domain, a transmembrane domain, and a short cytoplasmic tail. Understanding the intracellular trafficking of S is relevant to SARS-CoV-2 infection, and to vaccines expressing full-length S from mRNA or adenovirus vectors. Here we report a proteomic screen for cellular factors that interact with the cytoplasmic tail of S. We confirm interactions with the COPI and COPII vesicle coats, ERM family actin regulators, and the WIPI3 autophagy component. The COPII binding site promotes exit from the endoplasmic reticulum, and although binding to COPI should retain S in the early Golgi where viral budding occurs, there is a suboptimal histidine residue in the recognition motif. As a result, S leaks to the surface where it accumulates and can direct the formation of multinucleate syncytia. Thus, the trafficking signals in the tail of S indicate that syncytia play a role in the SARS-CoV-2 lifecycle

DEK influences the trade-off between growth and arrest via H2A.Z-nucleosomes in Arabidopsis

The decision of whether to grow and proliferate or to restrict growth and develop resilience to stress is a key biological trade-off. In plants, constitutive growth results in increased sensitivity to environmental stress1,2. The underlying mechanisms controlling this decision are however not well understood. We used temperature as a cue to discover regulators of this process in plants, as it both enhances growth and development rates within a specific range and is also a stress at extremes. We found that the conserved chromatin-associated protein DEK plays a central role in balancing the response between growth and arrest in Arabidopsis, and it does this via H2A.Z-nucleosomes. DEK target genes show two distinct categories of chromatin architecture based on the distribution of H2A.Z in +1 nucleosome and gene body, and these predict induction or repression by DEK. We show that these chromatin signatures of DEK target genes are conserved in human cells, suggesting that DEK may act through an evolutionarily conserved mechanism to control the balance between growth and arrest in plants and animals

Multidimensional Dynamics of the Proteome in the Neurodegenerative and Aging Mammalian Brain

Neurodegenerative diseases are characterized by the abnormal accumulation of aggregated proteins in the brain. Using in vivo pulse isotope labeling, we screened the proteome for changes in protein turnover and abundance in multiple mouse models of neurodegeneration. These data suggest that the disease state of pathologically affected tissue is characterized by a proteome-wide increase in protein turnover and repair. In contrast, in healthy wild-type mice, aging in the mammalian brain is associated with a global slowdown in protein turnover.Peer reviewe

Structural Organization and Dynamics of Homodimeric Cytohesin Family Arf GTPase Exchange Factors in Solution and on Membranes

Membrane dynamic processes require Arf GTPase activation by guanine nucleotide exchange factors (GEFs) with a Sec7 domain. Cytohesin family Arf GEFs function in signaling and cell migration through Arf GTPase activation on the plasma membrane and endosomes. In this study, the structural organization of two cytohesins (Grp1 and ARNO) was investigated in solution by size exclusion-small angle X-ray scattering and negative stain-electron microscopy and on membranes by dynamic light scattering, hydrogen-deuterium exchange-mass spectrometry and guanosine diphosphate (GDP)/guanosine triphosphate (GTP) exchange assays. The results suggest that cytohesins form elongated dimers with a central coiled coil and membrane-binding pleckstrin-homology (PH) domains at opposite ends. The dimers display significant conformational heterogeneity, with a preference for compact to intermediate conformations. Phosphoinositide-dependent membrane recruitment is mediated by one PH domain at a time and alters the conformational dynamics to prime allosteric activation by Arf-GTP. A structural model for membrane targeting and allosteric activation of full-length cytohesin dimers is discussed

Recruitment of trimeric eIF2 by phosphatase non-catalytic subunit PPP1R15B

Regulated protein phosphorylation controls most cellular processes. The protein phosphatase PP1 is the catalytic subunit of many holoenzymes that dephosphorylate serine/threonine residues. How these enzymes recruit their substrates is largely unknown. Here, we integrated diverse approaches to elucidate how the PP1 non-catalytic subunit PPP1R15B (R15B) captures its full trimeric eIF2 substrate. We found that the substrate-recruitment module of R15B is largely disordered with three short helical elements, H1, H2, and H3. H1 and H2 form a clamp that grasps the substrate in a region remote from the phosphorylated residue. A homozygous N423D variant, adjacent to H1, reducing substrate binding and dephosphorylation was discovered in a rare syndrome with microcephaly, developmental delay, and intellectual disability. These findings explain how R15B captures its 125 kDa substrate by binding the far end of the complex relative to the phosphosite to present it for dephosphorylation by PP1, a paradigm of broad relevance.</p