281 research outputs found
Wide baseline stereo matching with convex bounded-distortion constraints
Finding correspondences in wide baseline setups is a challenging problem.
Existing approaches have focused largely on developing better feature
descriptors for correspondence and on accurate recovery of epipolar line
constraints. This paper focuses on the challenging problem of finding
correspondences once approximate epipolar constraints are given. We introduce a
novel method that integrates a deformation model. Specifically, we formulate
the problem as finding the largest number of corresponding points related by a
bounded distortion map that obeys the given epipolar constraints. We show that,
while the set of bounded distortion maps is not convex, the subset of maps that
obey the epipolar line constraints is convex, allowing us to introduce an
efficient algorithm for matching. We further utilize a robust cost function for
matching and employ majorization-minimization for its optimization. Our
experiments indicate that our method finds significantly more accurate maps
than existing approaches
Cross-Lingual Alignment of Contextual Word Embeddings, with Applications to Zero-shot Dependency Parsing
We introduce a novel method for multilingual transfer that utilizes deep
contextual embeddings, pretrained in an unsupervised fashion. While contextual
embeddings have been shown to yield richer representations of meaning compared
to their static counterparts, aligning them poses a challenge due to their
dynamic nature. To this end, we construct context-independent variants of the
original monolingual spaces and utilize their mapping to derive an alignment
for the context-dependent spaces. This mapping readily supports processing of a
target language, improving transfer by context-aware embeddings. Our
experimental results demonstrate the effectiveness of this approach for
zero-shot and few-shot learning of dependency parsing. Specifically, our method
consistently outperforms the previous state-of-the-art on 6 tested languages,
yielding an improvement of 6.8 LAS points on average.Comment: NAACL 201
Determinants of inpatient rehabilitation length of stay and discharge modality after hip and knee replacement surgery in Switzerland : a retrospective observational study
QUESTIONS UNDER STUDY / PRINCIPLES: The aims of this study were to identify the determinants influencing the inpatient rehabilitation length of stay (LoS) and discharge modality (DisMod) after hip or knee replacement surgery.
METHODS: Data were retrieved for 306 patients (185 females, 121 males) who were admitted to a Swiss orthopaedic rehabilitation facility between 2007 and 2008 after hip or knee replacement surgery. LoS and DisMod were extracted from the medical files along with an additional seven binary and six continuous variables (including scores of timed-get-up-and-go [TUG], walking distance [WDT] and stair climbing tests [FIM_St]). Nonparametric procedures were used to detect differences between the gender groups. For the analysis of the LoS determinants, a linear regression model was used. The nonmotor performance test determinants of DisMod were analysed using a logistic regression model, whereas the motor performance test determinants were examined using binary classification. For both regression models, a backward procedure was used.
RESULTS: Unlike DisMod, LoS calculations were conducted after stratification for gender. The simplified regression models explained 22% (females) and 31% (males) of the LoS variance and 20% (both genders) of the DisMod variance. TUG, WDT and FIM_St were all important predictors for LoS, whereas DisMod could be best predicted by WDT.
CONCLUSIONS: Patients with good motor ability at admission were discharged earlier and more frequently to home. These findings might be of importance for preoperative physiotherapeutic care and might help to improve care planning as well as more accurately predict the access to inpatients beds and the allocation of resources
Neural Injective Functions for Multisets, Measures and Graphs via a Finite Witness Theorem
Injective multiset functions have a key role in the theoretical study of
machine learning on multisets and graphs. Yet, there remains a gap between the
provably injective multiset functions considered in theory, which typically
rely on polynomial moments, and the multiset functions used in practice, which
rely on \unicode{x2014} whose injectivity on
multisets has not been studied to date.
In this paper, we bridge this gap by showing that moments of neural networks
do define injective multiset functions, provided that an analytic
non-polynomial activation is used. The number of moments required by our theory
is optimal essentially up to a multiplicative factor of two. To prove this
result, we state and prove a , which is of
independent interest.
As a corollary to our main theorem, we derive new approximation results for
functions on multisets and measures, and new separation results for graph
neural networks. We also provide two negative results: (1) moments of
piecewise-linear neural networks cannot be injective multiset functions; and
(2) even when moment-based multiset functions are injective, they can never be
bi-Lipschitz.Comment: NeurIPS 2023 camera-read
Feasibility and effectiveness of thoracic spine mobilization on sympathetic/parasympathetic balance in a healthy population - a randomized controlled double-blinded pilot study
Background
Physiotherapists often use thoracic spine mobilization (TSM) to reduce pain in patients with back disorders via a reduction of sympathetic activity. There is a “trade-off” in the activity of the sympathetic and parasympathetic nervous system activity. A sympathetic/parasympathetic balance (SPB) is needed to guarantee body homeostasis. However, body homeostasis is seldom considered as an aim of the treatment from the perspective of most physiotherapists. Strong empirical evidence for the effects of TSM on the SPB is still lacking.
Some studies showed that spinal manipulation may yield beneficial effects on SPB. Therefore, it could be hypothesized that TSM is feasible and could influence SPB reactions. The primary aim was to describe the participants’ adherence to the intervention and to the measurement protocol, to identify unexpected adverse events (UAE) after TSM, to evaluate the best method to measure SPB parameters (heart rate variability (HRV), blood pressure (BP), heart rate (HR), skin perfusion and erythema) and to estimate the investigation procedure. The secondary aim was to assess the effects of TSM on SPB parameters in a small sample of healthy participants.
Methods
This crossover pilot study investigated TSM using posterior-anterior mobilization (PAM) and anterior-posterior mobilization (APM) on segments T6 to T12 in twelve healthy participants during two consecutive days. To evaluate feasibility, the following outcomes were assessed: adherence, UAE, data collection and data analysis. To evaluate the effect of TSM on SPB, HRV, BP, HR, skin perfusion and erythema were measured.
Results
The adherence was 100%. No UAE were reported. PAM showed larger effect sizes compared to APM in many secondary variables.
Conclusions
Although 100% maximal adherence was reached and no UAE were observed, data recording in future studies should be done during a second time interval while the data transfer from device to the computer software should occur immediately after completion of each participant’s measurement. The results of this pilot study suggest that PAM can reduce HRV HF and HRV ratio LF/HF and increase HR.
Trial registration
ClinicalTrail.gov (NCT02832141)
The Alternative Choice of Constitutive Exons throughout Evolution
Alternative cassette exons are known to originate from two processes
exonization of intronic sequences and exon shuffling. Herein, we suggest an
additional mechanism by which constitutively spliced exons become alternative
cassette exons during evolution. We compiled a dataset of orthologous exons
from human and mouse that are constitutively spliced in one species but
alternatively spliced in the other. Examination of these exons suggests that
the common ancestors were constitutively spliced. We show that relaxation of
the 59 splice site during evolution is one of the molecular mechanisms by which
exons shift from constitutive to alternative splicing. This shift is associated
with the fixation of exonic splicing regulatory sequences (ESRs) that are
essential for exon definition and control the inclusion level only after the
transition to alternative splicing. The effect of each ESR on splicing and the
combinatorial effects between two ESRs are conserved from fish to human. Our
results uncover an evolutionary pathway that increases transcriptome diversity
by shifting exons from constitutive to alternative splicin
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