Search

We investigate the problem of building a suffix array substring index for inputs significantly larger than main memory. This problem is especially important in the context of biological sequence analysis, where biological polymers can be thought of as very large contiguous strings. The objective is to index every substring of these long strings to facilitate efficient queries. We propose a new simple, scalable, and inherently parallelizable algorithm for building a suffix array for out-of-core strings. Our new algorithm, Suffix Rank , scales to arbitrarily large inputs, using disk as a memory extension. It solves the problem in just O (log n ) scans over the disk-resident data. We evaluate the practical performance of our new algorithm, and show that for inputs significantly larger than the available amount of RAM, it scales better than other state-of-the-art solutions, such as eSAIS, SAscan , and eGSA.

Nonunions about the hip occur as a result of femoral neck, intertrochanteric, and certain subtrochanteric fractures. Treatment of a hip fracture nonunion allows for the choice between hip preservation or arthroplasty. The goal of this study was to examine outcomes of hip-preservation nonunion surgery METHODS: Patients who underwent hip preservation for a fracture nonunion of the femoral neck, intertrochanteric and subtrochanteric region to 1 cm below the lesser trochanter over a 10-year period were identified in our nonunion registry. Patients were followed for a minimum of 1 year. Functional outcomes were recorded at follow-up visits. For comparison regarding surgical and hospital outcomes, a group of 23 patients who underwent conversion total hip arthroplasties (cTHA) at the same academic medical center was reviewed. Quality measures such as length of stay, reoperation, and complications were collected. All statistics analysis utilized IBM SPSS 25 (Armonk, NY) RESULTS: Thirty patients who underwent 30 hip-preserving nonunion surgeries were analyzed and compared with 23 cTHA patients. Twenty-nine nonunions went on to heal (average time to union 6.3 months). There was improvement in functional outcome scores for the hip preservation group between baseline and latest follow-up (p 0.001). Reoperation was required in five patients (17%), including four failed to heal and required a second repair to gain union and one failure that was converted to THA rather than attempt a second nonunion repair. Hip preservation failures were older than those that healed with the index treatment (p = 0.11). There was no significant difference in hospital length of stay, complication rate, or need for reoperation when compared to cTHA group.Hip-preserving surgery is an option that should be considered for patients with nonunion of fractures about the hip. The rates of complications (20.3 vs 17.3%) and reoperation (16.7 vs 17.3%) were equivalent to conversion THA. Excellent outcomes can be achieved in terms of radiographic union and function with hip preservation.