Statistics Seminar

Title: BASIN: Bayesian mAtrix variate normal model with Spatial and sparsIty priors in Non-negative deconvolution 

Abstract: Spatial transcriptomics allows researchers to visualize and analyze gene expression within the precise location of tissues or cells. It provides spatially resolved gene expression data but often lacks cellular resolution, necessitating cell type deconvolution to infer cellular composition at each spatial location. In this paper we propose BASIN for cell type deconvolution, which models deconvolution as a nonnegative matrix factorization (NMF) problem incorporating graph Laplacian prior. Rather than find a deterministic optima like other recent methods, we propose a matrix variate Bayesian NMF method with nonnegativity and sparsity priors, in which the variables are maintained in their matrix form to derive a more efficient matrix normal posterior. BASIN employs a Gibbs sampler to approximate the posterior distribution of cell type pro- portions and other parameters, offering a distribution of possible solutions, enhancing robustness and providing inherent uncertainty quantification. The performance of BASIN is evaluated on different spatial transcriptomics datasets and outperforms other deconvolution methods in terms of accuracy and efficiency. The results also show the effect of the incorporated priors and reflect a truncated matrix normal distribution as we expect. This is a joint work with Jiasen Zhang (CWRU Math PhD student) and Liangliang Zhang (CWRU Biostatistics faculty). 

 

Date:
-
Location:
MDS 220

Physics & Astronomy Colloquium

Dr. Elise Novitski, University of Washington

Title: A new approach to measuring neutrino mass

Abstract: Of all the fundamental fermion masses, those of the neutrinos alone remain unmeasured. From their unknown origin to their effects on the evolution of the universe, neutrino masses are of interest across cosmology, nuclear physics, and particle physics. Neutrino oscillation experiments have set a non-zero lower limit on the mass scale, in contradiction to the original Standard Model prediction. To measure neutrino mass precisely and directly one must turn to beta decay and search for a telltale distortion in the spectrum. I will describe a new technique called Cyclotron Radiation Emission Spectroscopy (CRES), in which beta decay of tritium occurs in a magnetic field and each electron's ~1 fW of cyclotron radiation is directly detected. Electron energies are then determined via a relativistic relationship between energy and frequency. I will present the first CRES-based mass limits from the Project 8 experiment, which demonstrate the promise of this technique for surmounting the systematic and statistical barriers that currently limit the precision of direct neutrino mass measurements. I will also describe the next steps on the path to sensitivity to a mass of 40 meV/c^2, covering the entire inverted ordering of neutrino masses

Date:
-
Location:
CP 153
Event Series:

MacAdam Student Observatory Kentucky Sky Talk

Title: Our Expanding Universe: What Lies Ahead?

Abstract: Our Universe is expanding at an increasing rate. What does the future hold? What will be here one billion years from now? A trillion years from now?.

Zoom Link: https://uky.zoom.us/j/88994568052

YouTube Link: You can find information about the impending nova, T Coronae Borealis, here- https://observatory.as.uky.edu/t-crb

You may park adjacent to the observatory in parking structure #2 one hour prior to the SkyTalk. 

After parking, please exit the parking structure come down one of the east exits, closest to the Young Library. 

To learn more about astronomy and our outreach events follow us on:

To watch previous SkyTalks visit our YouTube channel: https://www.youtube.com/channel/UCNg3wv7dVHq2_hBrOmTXMVg 

Date:
-
Location:
CP 153
Event Series:

Physics & Astronomy Colloquium

Dr. Ambrose Seo, University of Kentucky

Title: Shaping Light and Charge in Two-Dimensional Materials with Plasmonic Nanostructures

Abstract: Two-dimensional materials such as MoS2 are just one atom thick, which gives them remarkable optical and electronic properties, but also makes them challenging to use efficiently in devices, since their ultrathin nature limits how strongly they interact with light. During my sabbatical in Seoul, I explored new ways to overcome this challenge by combining MoS2 with carefully designed metallic nanostructures that can trap and guide light at the nanoscale. By embedding gold or silver nanowires and nanogrooves beneath or alongside MoS2, we found that we could significantly boost its light emission, collect photo-generated charges more effectively, and improve the efficiency of heterostructures that pair MoS2 with oxide semiconductors. These studies show how "plasmonic" effects, i.e., collective oscillations of electrons in metals, can be harnessed to control light–matter interactions in atomically thin materials. I will present the key outcomes of these projects and discuss how they point toward future opportunities for next-generation devices.

Date:
-
Location:
CP 153
Event Series:
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