200 research outputs found
The Influence of the Gait-Related Arm Swing on Elevation Gain Measured by Sport Watches
Abstract The elevation gain is an important contributor to the total workload in endurance sports. The purpose of this study was to evaluate the influence of the arm swing on elevation gain in three sport watches (Garmin® Forerunner 910XT, Polar® RS800CX and Suunto® Ambit2) on a flat 400 m outdoor track. Altogether, a total of 120 repetitions of 1,200 m were performed at self-selected speeds corresponding to strolling, walking, jogging and running. During the assessment two devices of each sport watch, one secured on the hip and one on the wrist, were worn by the participants. A small but significant (effect size = .39; p < .001) influence of the arm swing on elevation was revealed in all sport watches. Elevation indication errors recorded on the wrist were significantly larger than the ones recorded on the hip (4.0-7.4 vs. 1.2-5.7 m per 1,200 m; p < .05). Furthermore, when wearing the devices on the wrist, errors in elevation indication increased when gait speed increased. Users should be aware that wearing the devices on the hip can significantly decrease measurement errors. This might be especially relevant for activities with high dynamics, such as jogging and running
Analyzing and Explaining Image Classifiers via Diffusion Guidance
While deep learning has led to huge progress in complex image classification
tasks like ImageNet, unexpected failure modes, e.g. via spurious features, call
into question how reliably these classifiers work in the wild. Furthermore, for
safety-critical tasks the black-box nature of their decisions is problematic,
and explanations or at least methods which make decisions plausible are needed
urgently. In this paper, we address these problems by generating images that
optimize a classifier-derived objective using a framework for guided image
generation. We analyze the behavior and decisions of image classifiers by
visual counterfactual explanations (VCEs), detection of systematic mistakes by
analyzing images where classifiers maximally disagree, and visualization of
neurons to verify potential spurious features. In this way, we validate
existing observations, e.g. the shape bias of adversarially robust models, as
well as novel failure modes, e.g. systematic errors of zero-shot CLIP
classifiers, or identify harmful spurious features. Moreover, our VCEs
outperform previous work while being more versatile
Detection of collinear high energetic di-photon signatures with Micromegas Detectors
The search for weakly interacting, light particles that couple to photons
received significant attention in recent years. When those particles are
produced at high energies, they lead to two, nearly collinear photons after
their decay and hence can be detected by an electromagnetic calorimeter system.
The typical dominant background in searches for those high energetic weakly
particles are single, high energetic photons, which leave similar signatures in
a standard calorimeter system. One promising approach to separate signal from
background events is to employ a dedicated pre-shower detector in front of the
calorimeter that can distinguish one- and two-photon signatures. In this work
we present a conceptual design of such detector which is able to separate one
from two collinear photon signatures with efficiencies between 20% to 80% for
two photons separated by 0.1mm to 2mm, respectively, with energies above 300
GeV and a background rejection of more than 90%. Our pre-shower detector design
has an active surface area of 10cm x 10cm, a depth of 230mm and is based on
Micromegas detectors, thus offering a cost effective solution.Comment: 8 pages, 6 figure
Management of acute small bowel obstruction from intestinal adhesions: indications for laparoscopic surgery in a community teaching hospital
Purpose: The aim of this study is to compare the results of laparoscopic management of acute small bowel obstruction (SBO) from abdominal adhesions to both exploratory laparotomy and secondary conversion to open surgery. Materials and methods: Ninety-three patients (mean age 61years) with adhesion-induced SBO were divided into successful laparoscopy (66 patients [71%]), secondary conversion (24 [26%]), and primary laparotomy (three patients). Results: Patients with successful laparoscopy had more simple adhesions (57%), fewer prior operations, and lower American Society of Anesthesiologists (ASA) class. Operative time was shortest in the laparoscopy group (74.3 ± 4.4min), as was the duration of both intensive care unit and hospital stay. Mortality was 6%, regardless of operative technique. Conclusions: A trial of laparoscopic adhesiolysis by a surgeon with advanced laparoscopic skills seems advisable in the majority of patients with acute adhesive SBO, whereas patients with more extensive adhesions, higher ASA class, and more than two prior abdominal operations often require laparotomy to achieve equally satisfactory outcom
The influence of the gait-related arm swing on elevation gain measured by sport watches
The elevation gain is an important contributor to the total workload in endurance sports. The purpose of this study was to evaluate the influence of the arm swing on elevation gain in three sport watches (Garmin® Forerunner 910XT, Polar® RS800CX and Suunto® Ambit2) on a flat 400 m outdoor track. Altogether, a total of 120 repetitions of 1,200 m were performed at self-selected speeds corresponding to strolling, walking, jogging and running. During the assessment two devices of each sport watch, one secured on the hip and one on the wrist, were worn by the participants. A small but significant (effect size = .39; p < .001) influence of the arm swing on elevation was revealed in all sport watches. Elevation indication errors recorded on the wrist were significantly larger than the ones recorded on the hip (4.0- 7.4 vs. 1.2-5.7 m per 1,200 m; p < .05). Furthermore, when wearing the devices on the wrist, errors in elevation indication increased when gait speed increased. Users should be aware that wearing the devices on the hip can significantly decrease measurement errors. This might be especially relevant for activities with high dynamics, such as jogging and running
Spurious Features Everywhere -- Large-Scale Detection of Harmful Spurious Features in ImageNet
Benchmark performance of deep learning classifiers alone is not a reliable
predictor for the performance of a deployed model. In particular, if the image
classifier has picked up spurious features in the training data, its
predictions can fail in unexpected ways. In this paper, we develop a framework
that allows us to systematically identify spurious features in large datasets
like ImageNet. It is based on our neural PCA components and their
visualization. Previous work on spurious features of image classifiers often
operates in toy settings or requires costly pixel-wise annotations. In
contrast, we validate our results by checking that presence of the harmful
spurious feature of a class is sufficient to trigger the prediction of that
class. We introduce a novel dataset "Spurious ImageNet" and check how much
existing classifiers rely on spurious features
Laparoscopic cholecystectomy as a teaching operation: comparison of outcome between residents and attending surgeons in 1,747 patients
Purpose: Standardized surgical training is increasingly confronted with the public demand for high quality of surgical care in modern teaching hospitals. The aim of this study was to compare the results of laparoscopic cholecystectomy (LC) performed by resident surgeons (RS) and attending surgeons (AS). Methods: In this retrospective review of prospectively collected data 1,747 LC were performed in a community hospital between 1999 and 2009. Seven hundred seventy operations were performed by RS. Parameters analysed included the duration of operation and length of hospital stay, intraoperative complications, 30-day morbidity and mortality. Results: Duration of operation was 88 (25-245) min for RS vs. 75 (30-190) min by AS (p = 0.001). Elective operations were shorter when performed by AS (70 (30-190) [AS] vs. 85 (25-240) [RS] min, p = 0.001). Length of hospital stay was shorter in patients treated by RS (4 (1-49) days [RS] vs. 5 (1-83) days [AS], p = 0.1). Intraoperative complications showed no differences between the groups (1.0% [RS] vs. 1.3% [AS], p = 0.6), whereas 30-day morbidity was lower in patients treated by RS (3.8% [RS] vs. 6.2% [AS], p = 0.02). Overall mortality was 0.6% and independent of surgical expertise (0.5% [RS] vs. 0.8% [AS], p = 0.5). Conclusions: Provided adequate training, supervision and patient selection, surgical residents are able to perform LC with results comparable to those of experienced surgeon
NaNu: Proposal for a Neutrino Experiment at the SPS Collider located at the North Area of CERN
Several experiments have been proposed in the recent years to study the
nature of tau neutrinos, in particular aiming for a first observation of tau
anti-neutrinos, more stringent upper limit on its anomalous magnetic moment as
well as new constrains on the strange-quark content of the nucleon. We propose
here a new low-cost neutrino experiment at the CERN North area, named NaNu
(North Area NeUtrino), compatible with the realization of the future SHADOWS
and HIKE experiments at the same experimental area.Comment: 7 pages, 6 figure
The Fragile Body in the Functional City: An Editorial
Changing circumstances force planning to re-define its role as a driving function shaping our cities today. One of the significant challenges to the century-old tradition of planning comes from the ageing population. The demand to age in place and its associated conditions particularly require renewed attention. This is, however, not an isolated and partisan topic, but speaks to the changing circumstances and highlights the dramatic shortcoming of a performance-oriented and segregationof-function-driven approach; one that is remnant of the early days of the planning discipline, but is still very much alive today. What has the discussion around ageing and the city brought up, and where are we headed? Two significant aspects are the body and moving away from a performance-oriented interpretation thereof, as well as a rethinking of participation not just as an information exercise, but as a co-design practice
JUNE-Germany: An Agent-Based Epidemiology Simulation including Multiple Virus Strains, Vaccinations and Testing Campaigns
The June software package is an open-source framework for the detailed
simulation of epidemics based on social interactions in a virtual population
reflecting age, gender, ethnicity, and socio-economic indicators in England. In
this paper, we present a new version of the framework specifically adapted for
Germany, which allows the simulation of the entire German population using
publicly available information on households, schools, universities,
workplaces, and mobility data for Germany. Moreover, JuneGermany incorporates
testing and vaccination strategies within the population as well as the
simultaneous handling of several different virus strains. First validation
tests of the framework have been performed for the state of Rhineland
Palatinate based on data collected between October 2020 and December 2020 and
then extrapolated to March 2021, i.e. the end of the second wave.Comment: 10 pages, 11 figure
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