Chip-firing groups of iterated cones

Let $\Gamma$ be a finite graph and let $\Gamma_n$ be the "$n$th cone over $\Gamma$" (i.e., the join of $\Gamma$ and the complete graph $K_n$). We study the asymptotic structure of the chip-firing group $\text{Pic}^0(\Gamma_n)$.Comment: 8 pages. v4: added Remark 1.

Critical Distance: The Postcolonial Novel and the Dilemma of Exile

In this dissertation, I argue that Edward Said‘s theory of exile offers a stronger version of human agency than do other postcolonial theories of identity which rely on poststructural theory, and therefore, his theory of exile provides a useful model for postcolonial criticism. His theory of exile animates almost all of his work from his earliest literary criticism to his later theoretical texts. By ―exile,‖ Said refers to the experience of peoples displaced from their homes for political reasons and to the experience of intellectual homelessness that a critic must have in order to be free of the constraints of cultural, ideological, and professional entanglements. However, he insists that exile is a traumatic experience that does not lead to transcendence but to a greater awareness of the contingency of human experience. In my first chapter, I establish how Said‘s theory of exile allows him to appropriate some of the lessons of poststructuralism without relinquishing the strong sense of human agency which drives his political commitments. In the following three chapters, I examine Said‘s relationship to three novelists – Joseph Conrad, V.S. Naipaul, and Salman Rushdie – to consider how his theory of exile is developed in relation to their work. In Joseph Conrad, Said found a fellow-traveler whose extreme depictions of the predicament of exile, especially the depiction of language‘s inability to ameliorate the isolation of exile through the production of new affiliations, remind Said that exile is an experience of trauma. Said had a publicly contentious relationship with V.S. Naipaul, but their works bear strikingly similar descriptions of the relationship between exile and writing. They both insist that exilic writing can lead to valuable self-knowledge. v However, Said insists that writing is an act of engagement which leads to new affiliations, but Naipaul‘s writing offers a place of solace which he can reconsider his life with clearer vision. Said very publicly defended Salman Rushdie and wrote admirably of his project. Rushdie‘s theory of migrancy mirrors Said‘s theory of exile by attempting to construct a complex relationship to the metropolitan center without surrendering strategic opposition to various forms of oppression

CppFlow: Generative Inverse Kinematics for Efficient and Robust Cartesian Path Planning

In this work we present CppFlow - a novel and performant planner for the Cartesian Path Planning problem, which finds valid trajectories up to 129x faster than current methods, while also succeeding on more difficult problems where others fail. At the core of the proposed algorithm is the use of a learned, generative Inverse Kinematics solver, which is able to efficiently produce promising entire candidate solution trajectories on the GPU. Precise, valid solutions are then found through classical approaches such as differentiable programming, global search, and optimization. In combining approaches from these two paradigms we get the best of both worlds - efficient approximate solutions from generative AI which are made exact using the guarantees of traditional planning and optimization. We evaluate our system against other state of the art methods on a set of established baselines as well as new ones introduced in this work and find that our method significantly outperforms others in terms of the time to find a valid solution and planning success rate, and performs comparably in terms of trajectory length over time. The work is made open source and available for use upon acceptance

Colocalization of neurons in optical coherence microscopy and Nissl-stained histology in Brodmann’s area 32 and area 21

Published in final edited form as: Brain Struct Funct. 2019 January ; 224(1): 351–362. doi:10.1007/s00429-018-1777-z.Optical coherence tomography is an optical technique that uses backscattered light to highlight intrinsic structure, and when applied to brain tissue, it can resolve cortical layers and fiber bundles. Optical coherence microscopy (OCM) is higher resolution (i.e., 1.25 µm) and is capable of detecting neurons. In a previous report, we compared the correspondence of OCM acquired imaging of neurons with traditional Nissl stained histology in entorhinal cortex layer II. In the current method-oriented study, we aimed to determine the colocalization success rate between OCM and Nissl in other brain cortical areas with different laminar arrangements and cell packing density. We focused on two additional cortical areas: medial prefrontal, pre-genual Brodmann area (BA) 32 and lateral temporal BA 21. We present the data as colocalization matrices and as quantitative percentages. The overall average colocalization in OCM compared to Nissl was 67% for BA 32 (47% for Nissl colocalization) and 60% for BA 21 (52% for Nissl colocalization), but with a large variability across cases and layers. One source of variability and confounds could be ascribed to an obscuring effect from large and dense intracortical fiber bundles. Other technical challenges, including obstacles inherent to human brain tissue, are discussed. Despite limitations, OCM is a promising semi-high throughput tool for demonstrating detail at the neuronal level, and, with further development, has distinct potential for the automatic acquisition of large databases as are required for the human brain.Accepted manuscrip

Paraxial diffusion-field retrieval

Unresolved spatially-random microstructure, in an illuminated sample, can lead to position-dependent blur when an image of that sample is taken using an incoherent imaging system. For a small propagation distance, between the exit surface of the sample and the entrance surface of a position-sensitive detector, the paraxial approximation implies that the blurring influence of the sample may be modeled using an anomalous-diffusion field. This diffusion field may have a scalar or tensor character, depending on whether the random microstructure has an autocorrelation function that is rotationally isotropic or anisotropic, respectively. Partial differential equations are written down and then solved, in a closed-form manner, for several variants of the inverse problem of diffusion-field retrieval given suitable intensity images. Both uniform-illumination and structured-illumination schemes are considered. Links are made, between the recovered diffusion field and certain statistical properties of the unresolved microstructure. The developed theory -- which may be viewed as a crudely parallel form of small-angle scattering under the Guinier approximation -- is applicable to a range of paraxial radiation and matter fields, such as visible light, x rays, neutrons, and electrons

The Skn7 Response Regulator of \u3ci\u3eSaccharomyces cerevisiae\u3c/i\u3e Interacts with Hsf1 In Vivo and Is Required for the Induction of Heat Shock Genes by Oxidative Stress

The Skn7 response regulator has previously been shown to play a role in the induction of stress-responsive genes in yeast, e.g., in the induction of the thioredoxin gene in response to hydrogen peroxide. The yeast Heat Shock Factor, Hsf1, is central to the induction of another set of stress-inducible genes, namely the heat shock genes. These two regulatory trans-activators, Hsf1 and Skn7, share certain structural homologies, particularly in their DNA-binding domains and the presence of adjacent regions of coiled-coil structure, which are known to mediate protein–protein interactions. Here, we provide evidence that Hsf1 and Skn7 interact in vitro and in vivo and we show that Skn7 can bind to the same regulatory sequences as Hsf1, namely heat shock elements. Furthermore, we demonstrate that a strain deleted for the SKN7 gene and containing a temperature-sensitive mutation in Hsf1 is hypersensitive to oxidative stress. Our data suggest that Skn7 and Hsf1 cooperate to achieve maximal induction of heat shock genes in response specifically to oxidative stress. We further show that, like Hsf1, Skn7 can interact with itself and is localized to the nucleus under normal growth conditions as well as during oxidative stress

Maternal and infant morbidity following birth before 27 weeks of gestation: a single centre study

Delivery at extreme preterm gestational ages (GA) [Formula: see text] weeks is challenging with limited evidence often focused only on neonatal outcomes. We reviewed management and short term maternal, fetal and neonatal outcomes of births for 132 women (22 + 0 to 26 + 6 weeks' GA) with a live fetus at admission to hospital and in labour or at planned emergency Caesarean section: 103 singleton and 29 (53 live fetuses) twin gestations. Thirty women (23%) had pre-existing medical problems, 110 (83%) had antenatal complications; only 17 (13%) women experienced neither. Major maternal labour and delivery complications affected 35 women (27%). 151 fetuses (97%) were exposed to antenatal steroids, 24 (15%) to tocolysis and 70 (45%) to magnesium sulphate. Delivery complications affected 11 fetuses, with 12 labour or delivery room deaths; survival to discharge was 75% (117/156), increasing with GA: 25% (1/4), 75% (18/24), 69% (29/42), 73% (33/45) and 88% (36/41) at 22, 23, 24, 25 and 26 weeks GA respectively (p = 0.024). No statistically important impact was seen from twin status, maternal illness or obstetric management. Even in a specialist perinatal unit antenatal and postnatal maternal complications are common in extreme preterm births, emphasising the need to include maternal as well as neonatal outcomes

Strategic Sales Conversations As A Foundation For Effective Partnership Selling

This paper presents a new sales organization tool, strategic sales conversations, that can be used to enhance relationships with customers. Strategic sales conversations are an adaptation of strategic conversations in an inter- and intra- organizational context in which the selling firm is attempting to utilize open and honest communication to better understand the long-term needs of the buying organization.  A process model of strategic sales conversations is developed and its implications are discussed.&nbsp