1,627 research outputs found
Comparison between classical annual maxima and peak over threshold approach concerning robustness
Partial duration series (peak over threshold) form a considerable alternative to the classical
annual maximum approach since they enlarge the information spectrum. The classical POT
approach is based on a Poisson distribution for the annual number of exceedances although
this is can be questionable in some cases. Therefore two different distributions (Binomial
and Gumbel-Schelling (Gumbel and Schelling (1950)) ) are considered. The results show
that they do rarely make a difference to the Poisson distribution. In a second step we
investigate the robustness in the sense of stability against the occurrence of extreme events
of the POT compared to annual maxima and show that in the case of extreme events the POT
behaves much more robust and fits very good to the data
Numerical Simulation of Intake Structures Like Street Inlets With Supercritical Flow Conditions
Ordinal pattern dependence between hydrological time series
Ordinal patterns provide a method to measure correlation between time series. In
contrast to classical correlation measures like the Pearson correlation coefficient they
are able to measure not only linear correlation but also non-linear correlation even
in the presence of non-stationarity. Hence, they are a noteworthy alternative to the
classical approaches when considering discharge series. Discharge series naturally
show a high variation as well as single extraordinary extreme events and, caused by
anthropogenic and climatic impacts, non-stationary behaviour. Here, the method
of ordinal patterns is used to compare pairwise discharge series derived from macroand
mesoscale catchments in Germany. Differences of coincident groups were detected
for winter and summer annual maxima. Hydrological series, which are mainly
driven by annual climatic conditions (yearly discharges and low water discharges)
showed other and in some cases surprising interdependencies between macroscale
catchments. Anthropogenic impacts as the construction of a reservoir or different
flood conditions caused by urbanization could be detected
Joint modeling of annual maximum precipitation across different duration levels
Summarizing a series of rainfall events for different duration levels by their annual maxima provides
valuable information. These statistics are e.g. the design base of urban drainage systems. Investigating
an entire set of duration levels, the dependence among them has to be taken into account. We propose
an approach where a set of generalized extreme value distributions and a D-vine copula are
exibly
parameterized by the set of duration levels of interest. A priori, it is not necessary to fix the duration
levels nor the number of duration levels. This joint model produces increasing values for both, longer
duration levels and larger return periods. In a sample application, we show that this model is
exible
enough to capture variations across the duration levels while reproducing the correlation structure of
the data. A joint probabilistic model allows to study a new set of design questions where conditional
probabilities or joint return periods are of interest. This is for instance the case when nested sub-
basins are studied. An urban area within a larger catchment will be sensitive to annual maxima of
shorter durations due to high intensities while the enclosing catchment is prone to annual maxima of
long durations due to huge volumes. A risk analysis of the entire catchment requires a joint study of
both and an approach where the duration levels' dependence is taken into account
Early functional results after Hemiarthroplasty for femoral neck fracture: a randomized comparison between a minimal invasive and a conventional approach
BACKGROUND: A minimal invasive approach for elective hip surgery has been implemented in our institution in the past. It is widely hypothesized that implanting artificial hips in a minimal invasive fashion decreases surgical trauma and is helpful in the rehabilitation process in elective hip surgery. Thereby geriatric patients requiring emergency hip surgery also could theoretically benefit from a procedure that involves less tissue trauma. METHODS: Sixty patients who sustained a fractured neck of femur were randomly assigned into two groups. In the minimal invasive arm, the so called “direct anterior approach” (DAA) was chosen, in the conventional arm the Watson-Jones-Approach was used for implantation of a bipolar hemi-arthroplasty. Primary outcome parameter was the mobility as measured by the four-item-Barthel index. Secondary outcome parameters included pain, haemoglobin-levels, complications, duration of surgery, administration of blood transfusion and external length of incision. Radiographs were evaluated. RESULTS: A statistically significant difference (p = 0,009) regarding the mobility as measured with the four-item Barthel index was found at the 5th postoperative day, favouring the DAA. Evaluation of the intensity of pain with a visual analogue scale (VAS) showed a statistically significant difference (p = 0,035) at day 16. No difference was evident in the comparison of radiographic results. CONCLUSIONS: Comparing two different approaches to the hip joint for the implantation of a bipolar hemi-arthroplasty after fractured neck of femur, it can be stated that mobilization status is improved for the DAA compared to the WJA when measured by the four-item Barthel index, there is less pain as measured using the VAS. There is no radiographic evidence that a minimal invasive technique leads to inferior implant position. Level of Evidence: Level II therapeutic study
Treatment of hip fractures using a minimal invasive approach for bipolar arthroplasty—a randomized trial
Pictures in Your Mind: Using Interactive Gesture-Controlled Reliefs to Explore Art
Tactile reliefs offer many benefits over the more classic raised line drawings or tactile diagrams, as depth, 3D shape, and surface textures are directly perceivable. Although often created for blind and visually impaired (BVI) people, a wider range of people may benefit from such multimodal material. However, some reliefs are still difficult to understand without proper guidance or accompanying verbal descriptions, hindering autonomous exploration.
In this work, we present a gesture-controlled interactive audio guide (IAG) based on recent low-cost depth cameras that can be operated directly with the hands on relief surfaces during tactile exploration. The interactively explorable, location-dependent verbal and captioned descriptions promise rapid tactile accessibility to 2.5D spatial information in a home or education setting, to online resources, or as a kiosk installation at public places.
We present a working prototype, discuss design decisions, and present the results of two evaluation studies: the first with 13 BVI test users and the second follow-up study with 14 test users across a wide range of people with differences and difficulties associated with perception, memory, cognition, and communication. The participant-led research method of this latter study prompted new, significant and innovative developments
Political Participation of Young People and Democracy in Europe: Literature Review and Overview of Quantitative International Databases; Working Paper for the 15 th Nordic Youth Research Symposium, 13-15 June 2022, Session 2, Civic Participation; Interim Report
The promotion of democratic awareness and democratic values among young people in Europe is an important goal of European youth policy. In various documents on democracy and young people, European institutions assume that increased participation among young people results in strengthening a democratic Europe. Measuring democratic values and participation of young people is therefore a core element of European evidence-based policy, resulting in a massive body of studies that address statistical relationships between participation, democracy and young people. This brings up the question of how guiding concepts like participation, democratic attitude, political interest and civic citizenship are measured and are compared at the European level. This working paper is part of an ongoing research project to find answers to these questions and in this sense can give first or preliminary answers. The paper consists of two main parts. First, we present an overview of international databases and surveys on democracy and participation. Second, based on Systematic Literature Review (SLR), we analyse 78 recent studies, which use these data to draw conclusions on the relationship between democracy, participation and young people. With our paper, we want to contribute critically to the discussion on the comparability of data and studies on democracy and participation, as well as to the discussion on the relevance of these concepts and the conclusions drawn from them for European youth policy
Spatio-temporal propagation of Ca2+ signals by cyclic ADP-ribose in 3T3 cells stimulated via purinergic P2Y receptors
The role of cyclic ADP-ribose in the amplification of subcellular and global Ca2+ signaling upon stimulation of P2Y purinergic receptors was studied in 3T3 fibroblasts. Either (1) 3T3 fibroblasts (CD38− cells), (2) 3T3 fibroblasts preloaded by incubation with extracellular cyclic ADP-ribose (cADPR), (3) 3T3 fibroblasts microinjected with ryanodine, or (4) 3T3 fibroblasts transfected to express the ADP-ribosyl cyclase CD38 (CD38+ cells) were used. Both preincubation with cADPR and CD38 expression resulted in comparable intracellular amounts of cyclic ADP-ribose (42.3 ± 5.2 and 50.5 ± 8.0 pmol/mg protein). P2Y receptor stimulation of CD38− cells yielded a small increase of intracellular Ca2+ concentration and a much higher Ca2+ signal in CD38-transfected cells, in cADPR-preloaded cells, or in cells microinjected with ryanodine. Confocal Ca2+ imaging revealed that stimulation of ryanodine receptors by cADPR or ryanodine amplified localized pacemaker Ca2+ signals with properties resembling Ca2+ quarks and triggered the propagation of such localized signals from the plasma membrane toward the internal environment, thereby initiating a global Ca2+ wave
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