Multidecadal observations of the Antarctic ice sheet from restored analog radar records.

Airborne radar sounding can measure conditions within and beneath polar ice sheets. In Antarctica, most digital radar-sounding data have been collected in the last 2 decades, limiting our ability to understand processes that govern longer-term ice-sheet behavior. Here, we demonstrate how analog radar data collected over 40 y ago in Antarctica can be combined with modern records to quantify multidecadal changes. Specifically, we digitize over 400,000 line kilometers of exploratory Antarctic radar data originally recorded on 35-mm optical film between 1971 and 1979. We leverage the increased geometric and radiometric resolution of our digitization process to show how these data can be used to identify and investigate hydrologic, geologic, and topographic features beneath and within the ice sheet. To highlight their scientific potential, we compare the digitized data with contemporary radar measurements to reveal that the remnant eastern ice shelf of Thwaites Glacier in West Antarctica had thinned between 10 and 33% between 1978 and 2009. We also release the collection of scanned radargrams in their entirety in a persistent public archive along with updated geolocation data for a subset of the data that reduces the mean positioning error from 5 to 2.5 km. Together, these data represent a unique and renewed extensive, multidecadal historical baseline, critical for observing and modeling ice-sheet change on societally relevant timescales.

INSULIN DOSE REDUCTIONS IN THE INPATIENT SETTING: HOW MUCH IS ENOUGH?

ABBREVIATIONS: ANOVA = analysis of variance; BMI = body mass index; HbA1c = glycated hemoglobin; TDD = total daily dose; VAMC = Veterans Affairs Medical Center.

Optimal seed solver: optimizing seed selection in read mapping.

MOTIVATION: Optimizing seed selection is an important problem in read mapping. The number of non-overlapping seeds a mapper selects determines the sensitivity of the mapper while the total frequency of all selected seeds determines the speed of the mapper. Modern seed-and-extend mappers usually select seeds with either an equal and fixed-length scheme or with an inflexible placement scheme, both of which limit the ability of the mapper in selecting less frequent seeds to speed up the mapping process. Therefore, it is crucial to develop a new algorithm that can adjust both the individual seed length and the seed placement, as well as derive less frequent seeds. RESULTS: We present the Optimal Seed Solver (OSS), a dynamic programming algorithm that discovers the least frequently-occurring set of x seeds in an L-base-pair read in [Formula: see text] operations on average and in [Formula: see text] operations in the worst case, while generating a maximum of [Formula: see text] seed frequency database lookups. We compare OSS against four state-of-the-art seed selection schemes and observe that OSS provides a 3-fold reduction in average seed frequency over the best previous seed selection optimizations. AVAILABILITY AND IMPLEMENTATION: We provide an implementation of the Optimal Seed Solver in C++ at: https://github.com/CMU-SAFARI/Optimal-Seed-Solver CONTACT: hxin@cmu.edu, calkan@cs.bilkent.edu.tr or onur@cmu.edu SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Shifted Hamming distance: a fast and accurate SIMD-friendly filter to accelerate alignment verification in read mapping.

MOTIVATION: Calculating the edit-distance (i.e. minimum number of insertions, deletions and substitutions) between short DNA sequences is the primary task performed by seed-and-extend based mappers, which compare billions of sequences. In practice, only sequence pairs with a small edit-distance provide useful scientific data. However, the majority of sequence pairs analyzed by seed-and-extend based mappers differ by significantly more errors than what is typically allowed. Such error-abundant sequence pairs needlessly waste resources and severely hinder the performance of read mappers. Therefore, it is crucial to develop a fast and accurate filter that can rapidly and efficiently detect error-abundant string pairs and remove them from consideration before more computationally expensive methods are used. RESULTS: We present a simple and efficient algorithm, Shifted Hamming Distance (SHD), which accelerates the alignment verification procedure in read mapping, by quickly filtering out error-abundant sequence pairs using bit-parallel and SIMD-parallel operations. SHD only filters string pairs that contain more errors than a user-defined threshold, making it fully comprehensive. It also maintains high accuracy with moderate error threshold (up to 5% of the string length) while achieving a 3-fold speedup over the best previous algorithm (Gene Myers's bit-vector algorithm). SHD is compatible with all mappers that perform sequence alignment for verification.

Management of U-500 insulin users during inpatient admissions within a Veterans Affairs Medical Center.

AIMS: The purpose of this study was to compare inpatient insulin needs with usual home insulin needs for severely insulin resistant individuals using U-500 insulin. METHODS: This was a retrospective review of patients using U-500 insulin at one institution. Subjects were divided into 3 groups according to their pre-admission HbA1c [<8%, 8-8.99%, ≥9%] as glycemic control could impact inpatient insulin requirements. The primary outcome was the average total daily insulin dose during hospitalization. Secondary outcomes included the degree of blood sugar control during hospitalizations and insulin doses 6 months after discharge. RESULTS: Sixty-three patients with a total of 116 admissions were included. The average inpatient insulin dose was only 22.6% of the usual home insulin dose. There were no differences in the frequency of low blood sugars between glycemic control groups. By 6-months post-discharge the majority of subjects were back on their pre-admission dosing. CONCLUSIONS: Inpatient insulin needs were strikingly reduced (by average 75%) compared to home dosing regardless of pre-admission glycemic control. The results of this study should encourage institutions to assess their inpatient insulin protocols for U-500 using individuals.