1,659 research outputs found
Replication and discovery of musculoskeletal QTLs in LG/J and SM/J advanced intercross lines
AR056280 awarded to DAB and AL. AIHC supported by IMS and Elphinstone Scholarship from the University of Aberdeen. GRV supported by Medical Research Scotland (Vac-929-2016).Peer reviewedPublisher PD
Streaming Algorithm for Euler Characteristic Curves of Multidimensional Images
We present an efficient algorithm to compute Euler characteristic curves of
gray scale images of arbitrary dimension. In various applications the Euler
characteristic curve is used as a descriptor of an image.
Our algorithm is the first streaming algorithm for Euler characteristic
curves. The usage of streaming removes the necessity to store the entire image
in RAM. Experiments show that our implementation handles terabyte scale images
on commodity hardware. Due to lock-free parallelism, it scales well with the
number of processor cores. Our software---CHUNKYEuler---is available as open
source on Bitbucket.
Additionally, we put the concept of the Euler characteristic curve in the
wider context of computational topology. In particular, we explain the
connection with persistence diagrams
Electromotive instillation of mitomycin immediately before transurethral resection for patients with primary urothelial non-muscle invasive bladder cancer: a randomised controlled trial.
BACKGROUND:
The clinical effect of intravesical instillation of chemotherapy immediately after transurethral resection of bladder tumours (TURBT) has recently been questioned, despite its recommendation in guidelines. Our aim was to compare TURBT alone with immediate post-TURBT intravesical passive diffusion (PD) of mitomycin and immediate pre-TURBT intravesical electromotive drug administration (EMDA) of mitomycin in non-muscle invasive bladder cancer.
METHODS:
We did a multicentre, randomised, parallel-group study in patients with primary non-muscle invasive bladder cancer in three centres in Italy between Jan 1, 1994, and Dec 31, 2003. Patients were randomly assigned to receive treatment by means of stratified blocked randomisation across six strata. Patients and physicians giving the interventions were aware of assignment, but it was masked from outcome assessors and data analysts. Patients were randomly assigned to receive TURBT alone, immediate post-TURBT instillation of 40 mg PD mitomycin dissolved in 50 mL sterile water infused over 60 min, or immediate pre-TURBT instillation of 40 mg EMDA mitomycin dissolved in 100 mL sterile water with intravesical 20 mA pulsed electric current for 30 min. Our primary endpoints were recurrence rate and disease-free interval. Analyses were done by intention to treat. Follow-up for our trial is complete. This study is registered with ClinicalTrials.gov, number NCT01149174.
FINDINGS:
124 patients were randomly assigned to receive TURBT alone, 126 to receive immediate post-TURBT PD mitomycin, and 124 to receive immediate pre-TURBT EMDA mitomycin. 22 patients were excluded from our analyses because they did meet our eligibility criteria after TURBT: 11 had stage pT2 disease and 11 had carcinoma in situ. Median follow-up was 86 months (IQR 57-125). Patients assigned to receive EMDA mitomycin before TURBT had a lower rate of recurrence (44 [38%] of 117) than those assigned to receive PD mitomycin after TURBT (70 [59%] of 119) and TURBT alone (74 [64%] of 116; log-rank p<0·0001). Patients assigned to receive EMDA mitomycin before TURBT also had a higher disease-free interval (52 months, IQR 32-184) than those assigned to receive PD mitomycin after TURBT (16 months, 12-168) and TURBT alone (12 months, 12-37; log-rank p<0·0001). We recorded persistent bladder symptoms after TURBT in 18 (16%) of 116 patients in the TURBT-alone group (duration 3-7 days), 37 (31%) of 119 in the PD mitomycin post-TURBT group (duration 20-30 days), and 24 (21%) of 117 in the EMDA mitomycin pre-TURBT group (duration 7-12 days); haematuria after TURBT in eight (7%) of 116 patients in the TURBT-alone group, 16 (13%) of 119 in the PD mitomycin post-TURBT group, and 11 (9%) of 117 in the EMDA mitomycin pre-TURBT group; and bladder perforation after TURBT in five (4%) of 116 patients in the TURBT-alone group, nine (8%) of 119 in the PD mitomycin post-TURBT group, and seven (6%) of 117 in the EMDA mitomycin pre-TURBT group.
INTERPRETATION:
Intravesical EMDA mitomycin before TURBT is feasible and safe; moreover, it reduces recurrence rates and enhances the disease-free interval compared with intravesical PD mitomycin after TURBT and TURBT alone
The Theory of the Interleaving Distance on Multidimensional Persistence Modules
In 2009, Chazal et al. introduced -interleavings of persistence
modules. -interleavings induce a pseudometric on (isomorphism
classes of) persistence modules, the interleaving distance. The definitions of
-interleavings and generalize readily to multidimensional
persistence modules. In this paper, we develop the theory of multidimensional
interleavings, with a view towards applications to topological data analysis.
We present four main results. First, we show that on 1-D persistence modules,
is equal to the bottleneck distance . This result, which first
appeared in an earlier preprint of this paper, has since appeared in several
other places, and is now known as the isometry theorem. Second, we present a
characterization of the -interleaving relation on multidimensional
persistence modules. This expresses transparently the sense in which two
-interleaved modules are algebraically similar. Third, using this
characterization, we show that when we define our persistence modules over a
prime field, satisfies a universality property. This universality result
is the central result of the paper. It says that satisfies a stability
property generalizing one which is known to satisfy, and that in
addition, if is any other pseudometric on multidimensional persistence
modules satisfying the same stability property, then . We also show
that a variant of this universality result holds for , over arbitrary
fields. Finally, we show that restricts to a metric on isomorphism
classes of finitely presented multidimensional persistence modules.Comment: Major revision; exposition improved throughout. To appear in
Foundations of Computational Mathematics. 36 page
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