As general circulation models (GCMs) increase in complexity, the number of physical processes representing the climate system increases. A central goal of climate science is to understand how uncertainty in these physical processes, translates into uncertainty in the system response. But the very complexity of the GCMs generates a troublesome question: how do you properly define a stable and unchanging reference system with which to compare constituent elements and characterize their uncertainties? To navigate around this, we introduce a simple energy balance model (EBM) that accounts for the transport of both sensible and latent heat in the atmosphere. We demonstrate that the EBM accounts for approximately 90% of the inter-model spread in the temperature response for an ensemble of GCMs subjected to increasing CO2. We then calculate the unique model patterns of ocean heat uptake, radiative forcing, and radiative feedbacks and demonstrate that 100-years after an abrupt quadrupling of CO2 above preindustrial values, the largest source of uncertainty is the pattern and amplitude of radiative feedbacks. Using this, we identify regions of high feedback uncertainty and show how this can bias temperature responses in other regions.

Conventional diagnostics for tuberculosis use the patient’s sputum, mucus from the lower airways, as the primary sample type. Collecting sputum can be difficult and hazardous and for some patients, especially pediatric cases, sputum must be induced through an invasive procedure. An alternative to sputum samples is oral swabs, which have been used to detect the presence of Mycobacterium tuberculosis DNA in clinical trials. However, the current threshold of oral swabs is not yet sufficient for widespread implementation. In a new phase of assessing the viability of oral swab samples, nine different swab types were compared to improve DNA yield and subsequent qPCR readouts. The comparison was based on qPCR Cq values after spiking the swabs with mTB DNA, and analysis of each swab’s suitability for culturing. Earlier results suggest that oral swabs are a feasible alternative to sputum samples when using swabs that are heavily “flocked”, meaning that they have many small fiber particles deposited across a surface. Moreover, samples performed with dissolvable swabs may be better suited for further molecular and microbiological analysis.

Oral swab analysis (OSA) is a possible alternative sample type for tuberculosis diagnostics. It has been observed that tongue swabs contain greater amounts of Mycobacterium tuberculosis DNA than cheek swabs (p<0.0001). This project investigates whether other oral microbiota follow the same pattern by analyzing oral swabs from healthy controls and TB patients from South Africa. To determine the oral bacterial load, the first step was to optimize a universal bacterial PCR protocol that could be used on real samples. The Com1/769R primer set that amplifies the 16s region of prokaryotic DNA (Dorn-In, 2017) was selected after a literature review and tests with DNA from 5 different bacterial species at known amounts to compare sensitivity. Next, samples were collected from 5 healthy volunteers from Seattle. They provided two swabs each, one from their tongue and one from their cheek, which we then analyzed by PCR. Oral swab samples from South Africa were also analyzed by PCR. We found that the tongue swabs contained greater amounts of total bacterial DNA than the cheek swabs. For the healthy Seattle volunteers, the tongue swabs had an average of 294 times more DNA than the cheek swabs. For the South African samples, the tongue swabs had an average of 13.2 times more DNA than the cheek swabs. Our results suggest that there may be more prokaryotic DNA on the tongue than cheek. Our next steps are to test additional samples from South African subjects. This research could impact the development of future diagnostic tests that detect pathogens within the oral cavity.