3,248 research outputs found
On balanced planar graphs, following W. Thurston
Let be an orientation-preserving branched covering map of
degree , and let be an oriented Jordan curve passing through
the critical values of . Then is an oriented graph
on the sphere. In a group email discussion in Fall 2010, W. Thurston introduced
balanced planar graphs and showed that they combinatorially characterize all
such , where has distinct critical values. We give a
detailed account of this discussion, along with some examples and an appendix
about Hurwitz numbers.Comment: 17 page
STAT3 Genotypic Variant rs744166 and Increased Tyrosine Phosphorylation of STAT3 in IL-23 Responsive Innate Lymphoid Cells during Pathogenesis of Crohn\u27s Disease
Crohn\u27s disease (CD) results from dysregulated immune responses to gut microbiota in genetically susceptible individuals, affecting multiple areas of the gastrointestinal tract. Innate lymphoid cells (ILCs) are tissue-resident innate effector lymphocytes which play crucial roles in mucosal immune defense, tissue repair, and maintenance of homeostasis. The accumulation of IFN-γ-producing ILC1s and increased level of proinflammatory cytokines produced by ILCs has been observed in the inflamed terminal ileum of CD patients. To date, the precise mechanisms of ILC plasticity and gene regulatory pathways in ILCs remain unclear. Signal transducer and activator of transcription 3 (STAT3) regulates gene expression in a cell-specific, cytokine-dependent manner, involving multiple immune responses. This study proposes the positive correlation between the prevalence of STAT3 rs744166 risky allele A with the severity of disease in a cohort of 94 CD patients. In addition, the results suggest an increased STAT3 activity in the inflamed ileum of CD patients, compared to unaffected ileum sections. Notably, IL-23 triggers the differentiation of CD117+NKp44- ILC3s and induces the activation of STAT3 in both CD117+NKp44- and CD117-NKp44- ILC subsets, implying the involvement of STAT3 in the initiation of ILC plasticity. Moreover, carriage of STAT3 A risk allele exhibited a higher basal level of STAT3 tyrosine phosphorylation, and an increased IL-23 triggered the pSTAT3 level. We also demonstrated that there was no delayed dephosphorylation of STAT3 in ILCs of both A/A and G/G donors. Overall, the results of this study suggest that IL-23-induced activation of STAT3 in the CD117-NKp44- ILC1s involves in ILC1-to-ILC3 plasticity and a potential regulatory role of ILC1 function. Those genetically susceptible individuals carried STAT3 rs744166 risky allele appear to have higher basal and cytokine-stimulated activation of STAT3 signal, leading to prolonged inflammation and chronic relapse
Operating theatre time, where does it all go? A prospective observational study
Objective To assess the accuracy of surgeons and anaesthetists in predicting the time it will take them to complete an operation or procedure and therefore explain some of the difficulties encountered in operating theatre scheduling.
Design Single centre, prospective observational study.
Setting Plastic, orthopaedic, and general surgical operating theatres at a level 1 trauma centre serving a population of about 370 000.
Participants 92 operating theatre staff including surgical consultants, surgical registrars, anaesthetic consultants, and anaesthetic registrars.
Intervention Participants were asked how long they thought their procedure would take. These data were compared with actual time data recorded at the end of the case.
Primary outcome measure Absolute difference between predicted and actual time.
Results General surgeons underestimated the time required for the procedure by 31 minutes (95% confidence interval 7.6 to 54.4), meaning that procedures took, on average, 28.7% longer than predicted. Plastic surgeons underestimated by 5 minutes (−12.4 to 22.4), with procedures taking an average of 4.5% longer than predicted. Orthopaedic surgeons overestimated by 1 minute (−16.4 to 14.0), with procedures taking an average of 1.1% less time than predicted. Anaesthetists underestimated by 35 minutes (21.7 to 48.7), meaning that, on average, procedures took 167.5% longer than they predicted. The four specialty mean time overestimations or underestimations are significantly different from each other (P=0.01). The observed time differences between anaesthetists and both orthopaedic and plastic surgeons are significantly different (P<0.05), but the time difference between anaesthetists and general surgeons is not significantly different.
Conclusion The inability of clinicians to predict the necessary time for a procedure is a significant cause of delay in the operating theatre. This study suggests that anaesthetists are the most inaccurate and highlights the potential differences between specialties in what is considered part of the “anaesthesia time.
Axiomatic Interpretability for Multiclass Additive Models
Generalized additive models (GAMs) are favored in many regression and binary
classification problems because they are able to fit complex, nonlinear
functions while still remaining interpretable. In the first part of this paper,
we generalize a state-of-the-art GAM learning algorithm based on boosted trees
to the multiclass setting, and show that this multiclass algorithm outperforms
existing GAM learning algorithms and sometimes matches the performance of full
complexity models such as gradient boosted trees.
In the second part, we turn our attention to the interpretability of GAMs in
the multiclass setting. Surprisingly, the natural interpretability of GAMs
breaks down when there are more than two classes. Naive interpretation of
multiclass GAMs can lead to false conclusions. Inspired by binary GAMs, we
identify two axioms that any additive model must satisfy in order to not be
visually misleading. We then develop a technique called Additive
Post-Processing for Interpretability (API), that provably transforms a
pre-trained additive model to satisfy the interpretability axioms without
sacrificing accuracy. The technique works not just on models trained with our
learning algorithm, but on any multiclass additive model, including multiclass
linear and logistic regression. We demonstrate the effectiveness of API on a
12-class infant mortality dataset.Comment: KDD 201
Modeling Intrapersonal and Interpersonal Influences for Automatic Estimation of Therapist Empathy in Counseling Conversation
Counseling is usually conducted through spoken conversation between a
therapist and a client. The empathy level of therapist is a key indicator of
outcomes. Presuming that therapist's empathy expression is shaped by their past
behavior and their perception of the client's behavior, we propose a model to
estimate the therapist empathy by considering both intrapersonal and
interpersonal influences. These dynamic influences are captured by applying an
attention mechanism to the therapist turn and the historical turns of both
therapist and client. Our findings suggest that the integration of dynamic
influences enhances empathy level estimation. The influence-derived embedding
should constitute a minor portion in the target turn representation for optimal
empathy estimation. The client's turns (interpersonal influence) appear to
slightly surpass the therapist's own turns (intrapersonal influence) in empathy
estimation effectiveness. It is noted that concentrating exclusively on recent
historical turns can significantly impact the estimation of therapist empathy
Geodesic Mode Connectivity
Mode connectivity is a phenomenon where trained models are connected by a
path of low loss. We reframe this in the context of Information Geometry, where
neural networks are studied as spaces of parameterized distributions with
curved geometry. We hypothesize that shortest paths in these spaces, known as
geodesics, correspond to mode-connecting paths in the loss landscape. We
propose an algorithm to approximate geodesics and demonstrate that they achieve
mode connectivity.Comment: Published as a TinyPaper at ICLR 202
A Study on Prosodic Entrainment in Relation to Therapist Empathy in Counseling Conversation
Counseling is carried out as spoken conversation between a therapist and a
client. The empathy level expressed by the therapist is considered an important
index of the quality of counseling and often assessed by an observer or the
client. This research investigates the entrainment of speech prosody in
relation to subjectively rated empathy. Experimental results show that the
entrainment of intensity is more influential to empathy observation than that
of pitch or speech rate in client-therapist interaction. The observer and the
client have different perceptions of therapist empathy with the same entrained
phenomena in pitch and intensity. The client's intention to make adjustment on
pitch variation and intensity of speech is considered an indicator of the
client's perception of counseling quality.Comment: Accepted by INTERSPEECH 202
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