TY  - JOUR
A1  - Mikucki, Jill Ann
A1  - Schuler, C. G.
A1  - Digel, Ilya
A1  - Kowalski, Julia
A1  - Tuttle, M. J.
A1  - Chua, Michelle
A1  - Davis, R.
A1  - Purcell, Alicia
A1  - Ghosh, D.
A1  - Francke, G.
A1  - Feldmann, M.
A1  - Espe, C.
A1  - Heinen, Dirk
A1  - Dachwald, Bernd
A1  - Clemens, Joachim
A1  - Lyons, W. B.
A1  - Tulaczyk, S.
T1  - Field-Based planetary protection operations for melt probes: validation of clean access into the blood falls, antarctica, englacial ecosystem
JF  - Astrobiology
N2  - Subglacial environments on Earth offer important analogs to Ocean World targets in our solar system. These unique microbial ecosystems remain understudied due to the challenges of access through thick glacial ice (tens to hundreds of meters). Additionally, sub-ice collections must be conducted in a clean manner to ensure sample integrity for downstream microbiological and geochemical analyses. We describe the field-based cleaning of a melt probe that was used to collect brine samples from within a glacier conduit at Blood Falls, Antarctica, for geomicrobiological studies. We used a thermoelectric melting probe called the IceMole that was designed to be minimally invasive in that the logistical requirements in support of drilling operations were small and the probe could be cleaned, even in a remote field setting, so as to minimize potential contamination. In our study, the exterior bioburden on the IceMole was reduced to levels measured in most clean rooms, and below that of the ice surrounding our sampling target. Potential microbial contaminants were identified during the cleaning process; however, very few were detected in the final englacial sample collected with the IceMole and were present in extremely low abundances (∼0.063% of 16S rRNA gene amplicon sequences). This cleaning protocol can help minimize contamination when working in remote field locations, support microbiological sampling of terrestrial subglacial environments using melting probes, and help inform planetary protection challenges for Ocean World analog mission concepts.
Y1  - 2023
U6  - https://doi.org/10.1089/ast.2021.0102
SN  - 1557-8070 (online)
SN  - 153-1074 (print)
VL  - 23
IS  - 11
SP  - 1165
EP  - 1178
PB  - Liebert
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Grajewski, Matthias
A1  - Kleefeld, Andreas
T1  - Detecting and approximating decision boundaries in low-dimensional spaces
JF  - Numerical Algorithms
N2  - A method for detecting and approximating fault lines or surfaces, respectively, or decision curves in two and three dimensions with guaranteed accuracy is presented. Reformulated as a classification problem, our method starts from a set of scattered points along with the corresponding classification algorithm to construct a representation of a decision curve by points with prescribed maximal distance to the true decision curve. Hereby, our algorithm ensures that the representing point set covers the decision curve in its entire extent and features local refinement based on the geometric properties of the decision curve. We demonstrate applications of our method to problems related to the detection of faults, to multi-criteria decision aid and, in combination with Kirsch’s factorization method, to solving an inverse acoustic scattering problem. In all applications we considered in this work, our method requires significantly less pointwise classifications than previously employed algorithms.
KW  - MCDA
KW  - Inverse scattering problem
KW  - Fault approximation
KW  - Fault detection
Y1  - 2023
SN  - 1572-9265
N1  - Corresponding author: Matthias Grajewski
VL  - 93
IS  - 4
PB  - Springer Science+Business Media
CY  - Dordrecht
ER  -