Coding tasks, such as encryption of data or the generation of failure-tolerant codes, belong to the most computationaly expensive tasks inside the Linux kernel. Their integration into the kernel ...enables the user to transparently access these functionalities, encrypted hard disks can be used in the same way as unencrypted ones. Nevertheless, Linux as a monolithic kernel is not prepared to support these expensive tasks by accessing modern hardware accelerators, like graphics processing units (GPUs), as the corresponding accelerator libraries, like the CUDA-API for NVIDIA GPUs, only offer user-space APIs. Linux is often used in conjunction with parallel file systems in high performance cluster environments and the tremendous storage growth in these environments leads to the requirement of multi-error correcting codes. Parallel file systems, which often run on a storage cluster, are required to store the calculated results without huge waiting times. Whereas the frontend of such a storage cluster can be build with standard PCs, it is in contrast nearly impossible to build a capable RAID backend with end user hardware up to now.
This work investigated the potential of graphic cards for such coding applications like RAID in the Linux kernel. For this purpose, a special microdriver concept (Barracuda) has been designed that can be integrated into Linux without changing kernel APIs. For the investigation of the performance of this concept, the Linux RAID 6-system and the applied Reed-Solomon code have been exemplary extended and studied. The resulting measurements outline opportunities and limitations of our microdriver concept. On the one hand, the concept achieves a speed-up of 72 for complex, 8-failure correcting codes, while no additional speed-up can be generated for simpler, 2-error correcting codes. An example application for Barracuda could therefore be replacement of expensive RAID systems in cluster storage environments.
Writing efficient software for heterogeneous architectures equipped with modern accelerator devices presents a serious challenge to programmer productivity, creating a need for powerful ...performance-analysis tools to adequately support the software development process. To guide the design of such tools, we describe typical patterns of inefficient runtime behavior that may adversely affect the performance of applications that use general-purpose processors along with GPU devices through a CUDA compute engine. To evaluate the general impact of these patterns on application performance, we further present a micro benchmark suite that allows the performance penalty of each pattern to be quantified with results obtained on NVIDIA Fermi and Tesla architectures, indeed demonstrating significant delays. Furthermore this suite can be used as a default test scenario to add CUDA support to performance-analysis tools used in high-performance computing.
Computers are essential in research and industry, but they are also significant contributors to the worldwide power consumption. The LOEWE-CSC supercomputer addresses this problem by setting new ...standards in environmental compatibility as well as energy and cooling efficiency for high-performance and general-purpose computing. Designing a pervasively energy efficient compute center requires improvements in multiple fields. The hosting low-loss compute-center operates at a cooling overhead below 8% of the computer power. General purpose graphics processing units provide more compute performance per watt than standard processors. A balanced hardware configuration ensures that most of the compute power is available to the user when he employs optimized applications. Clever algorithms enable the user to fully exploit the computational potential and avoids to waste power when the processors idles, which is often a cause of inefficient programming. The LOEWE-CSC operated at 740MFlops/W during a Linpack benchmark run, by using commodity servers and ranked place 8 in the Green500 list of November 2010. These innovations provide a fundamental step towards cost-effective, environment-friendly exascale computing and IT operation.
Purpose
There is a paucity of studies on new vertebral body tethering (VBT) surgical constructs especially regarding their potentially motion-preserving ability. This study analyses their effects on ...the ROM of the spine.
Methods
Human spines (T10-L3) were tested under pure moment in four different conditions: (1) native, (2) instrumented with one tether continuously connected in all vertebrae from T10 to L3, (3) additional instrumented with a second tether continuously connected in all vertebrae from T11 to L3, and (4) instrumented with one tether and one titanium rod (hybrid) attached to T12, L1 and L2. The instrumentation was inserted in the left lateral side. The intersegmental ROM was evaluated using a magnetic tracking system, and the medians were analysed. Please check and confirm the author names and initials are correct. Also, kindly confirm the details in the metadata are correct. The mentioned information is correct
Results
Compared to the native spine, the instrumented spine presented a reduction of less than 13% in global ROM considering flexion–extension and axial rotation. For left lateral bending, the median global ROM of the native spine (100%) significantly reduced to 74.6%, 66.4%, and 68.1% after testing one tether, two tethers and the hybrid construction, respectively. In these cases, the L1-L2 ROM was reduced to 68.3%, 58.5%, and 38.3%, respectively. In right lateral bending, the normalized global ROM of the spine with one tether, two tethers and the hybrid construction was 58.9%, 54.0%, and 56.6%, respectively. Considering the same order, the normalized L1-L2 ROM was 64.3%, 49.9%, and 35.3%, respectively.
Conclusion
The investigated VBT techniques preserved global ROM of the spine in flexion–extension and axial rotation while reduced the ROM in lateral bending.
Background and purpose
A number of non‐motor features are known to precede motor manifestations of Parkinson's disease (PD). They are supposed to already represent the prodromal neurodegenerative ...state in those who later develop PD and are thus called prodromal markers. In this study, three prodromal markers, depression, rapid eye movement behaviour disorder (RBD) and hyposmia, were selected and were related to other prodromal features in elderly individuals without PD.
Methods
From the Tübinger Evaluation of Risk Factors for Early Detection of Neurodegeneration (TREND) study, 698 healthy individuals aged 50–80 years reporting one or more of the selected prodromal markers (SPMs), but without neurodegenerative disorders, were evaluated and classified according to the status of prodromal markers. Other prodromal PD‐related features were assessed with a 23‐item questionnaire and compared between participants with and without the three SPMs.
Results
Individuals with the SPMs for PD endorsed more of the additional possible prodromal features of PD than those without; of 23 possible prodromal features, the median number identified amongst participants with no SPMs was two, compared with four with one marker, five with two and seven with three (P < 0.001). Regarding individual SPMs, participants with depression and RBD endorsed five of 23 markers, compared with three for those with hyposmia (P = 0.001). There was no significant increase in the number of prodromal features amongst those with two SPMs compared with those with only one marker.
Conclusions
Individuals with the SPMs for PD report a higher prevalence of other prodromal PD symptoms. This may indicate that these markers can identify individuals at risk for PD.
The medial patellofemoral ligament (MPFL) is always damaged after patellar dislocation. In selected patients, MPFL reconstruction is necessary to restore a correct patellar tracking. Despite the ...large number of different techniques reported to reconstruct the MPFL, there is no consensus concerning the optimal procedure, and debates is still ongoing. The present study analysed the results after isolated MPFL reconstruction in patients with patellofemoral instability. Furthermore, a subgroup analysis of patients presenting pathoanatomical risk factors was made.
In November 2020, the main electronic databases were accessed. All articles reporting the results of primary isolated MPFL reconstruction for recurrent patellofemoral instability were considered for inclusion. Only articles reporting a minimum 12-month follow-up were eligible.
Data from a total of 1777 knees were collected. The mean age of the patients involved was 22.8 ± 3.4 years. The mean follow-up was 40.7 ± 25.8 months. Overall, the range of motion (+ 27.74; P < 0.0001) and all the other scores of interests improved at last follow-up: Kujala (+ 12.76; P = 0.0003), Lysholm (+ 15.69; P < 0.0001), Tegner score (+ 2.86; P = 0.006). Seventy-three of 1780 patients (4.1%) showed a positive apprehension test. Thirty of 1765 patients (1.7%) experienced re-dislocations, while 56 of 1778 patients (3.2%) showed persisting joint instability. Twenty-five of 1786 patients (1.4%) underwent revision surgeries.
Isolated MPFL reconstruction for recurrent patellofemoral instability provides reliable surgical outcomes. Patients with pathoanatomical predisposing factors reported worse surgical outcomes.
Test beam measurements at the test beam facilities of DESY have been conducted to characterise the performance of the EUDET-type beam telescopes originally developed within the EUDET project. The ...beam telescopes are equipped with six sensor planes using MIMOSA 26 monolithic active pixel devices. A programmable Trigger Logic Unit provides trigger logic and time stamp information on particle passage. Both data acquisition framework and offline reconstruction software packages are available. User devices are easily integrable into the data acquisition framework via predefined interfaces.
The biased residual distribution is studied as a function of the beam energy, plane spacing and sensor threshold. Its standard deviation at the two centre pixel planes using all six planes for tracking in a 6 GeV electron/positron-beam is measured to be (2.88 ± 0.08) µm. Iterative track fits using the formalism of General Broken Lines are performed to estimate the intrinsic resolution of the individual pixel planes. The mean intrinsic resolution over the six sensors used is found to be (3.24 ± 0.09) µm. With a 5 GeV electron/positron beam, the track resolution halfway between the two inner pixel planes using an equidistant plane spacing of 20 mm is estimated to (1.83 ± 0.03) µm assuming the measured intrinsic resolution. Towards lower beam energies the track resolution deteriorates due to increasing multiple scattering. Threshold studies show an optimal working point of the MIMOSA 26 sensors at a sensor threshold of between five and six times their RMS noise. Measurements at different plane spacings are used to calibrate the amount of multiple scattering in the material traversed and allow for corrections to the predicted angular scattering for electron beams.
Physical activity (PA) is a major contributor to healthy aging. However, physical inactivity is prevalent among the elderly in Germany, particularly in institutionalized settings such as nursing ...homes. This paper aims to describe the study objectives, design, methods, assessment types, collection schedules and considerations for analyzing the data within the BaSAlt study on facilitators and barriers for PA promotion in nursing homes.
We designed the BaSAlt study as a participatory intervention study with multiple measurement points in six to eight nursing homes with a total of approx. 200 residents using four main modules: (1) setting-level analysis of physical activity patterns, physical activity-related climate and physical activity-related interaction with ‘significant others,’ and organizational facilitators and barriers to physical activity, (2) physical-activity related individual-level analysis of objective and self-reported physical activity and sedentary behavior, a geriatric assessment with established procedures, assessment of people's activity and health biographies (biographical mapping) as well as their motivational, subjective well-being and distress status, and (3) a counseling module that integrates counseling at the setting level as well as individual physical activity counseling for residents. In module (4) evaluation, the effects of integrated counseling with regard to the implementation of PA promotion strategies are analyzed.
This study will extend our knowledge of physical activity promotion in German nursing homes. Its findings will inform governmental authorities, care professionals, and academics on how to reach a particular group, characterized by inactivity, multimorbidity, and a high prevalence of dementia, residing in nursing homes, a setting that will gain further relevance in the future.
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