807 research outputs found
Scoping assessment of free-field vibrations due to railway traffic
The number of railway lines both operational and under construction is growing rapidly, leading to an increase in the number of buildings adversely affected by ground-borne vibration (e.g. shaking and indoor noise). Post-construction mitigation measures are expensive, thus driving the need for early stage prediction, during project planning/development phases. To achieve this, scoping models (i.e. desktop studies) are used to assess long stretches of track quickly, in absence of detailed design information. This paper presents a new, highly customisable scoping model, which can analyse the effect of detailed changes to train, track and soil on ground vibration levels. The methodology considers soil stiffness and the combination of both the dynamic and static forces generated due to train passage. It has low computational cost and can predict free-field vibration levels in accordance with the most common international standards. The model uses the direct stiffness method to compute the soil Green's function, and a novel two-and-a-half dimensional (2.5D) finite element strategy for train-track interaction. The soil Green's function is modulated using a neural network (NN) procedure to remove the need for the time consuming computation of track-soil coupling. This modulation factor combined with the new train-track approach results in a large reduction in computational time. The proposed model is validated by comparing track receptance, free-field mobility and soil vibration with both field experiments and a more comprehensive 2.5D combined finite element-boundary element (FEM-BEM) model. A sensitivity analysis is undertaken and it is shown that track type, soil properties and train speed have a dominant effect on ground vibration levels. Finally, the possibility of using average shear wave velocity introduced for seismic site response analysis to predict vibration levels is investigated and shown to be reasonable for certain smooth stratigraphy's
Designing nutrition-based interventional trials for the future: addressing the known knowns
Abstract The consistent decline in critical illness mortality has a significant effect on trial design, whereby either an improbable effect sizes or large number of patients are required. The signal-to-noise ratio is of particular interest for the critically ill. When considering the potential signal, interventions need to match outcomes in regard to biological plausibility. Provision of nutrition is a complex decision with many underappreciated aspects of noise. However, a fundamental interaction is often not accounted for time. Working as a community to evolve trial design will be our challenge for nutrition interventions in the critically ill for the future
An fMRI Investigation of Preparatory Set in the Human Cerebral Cortex and Superior Colliculus for Pro- and Anti-Saccades
Previous studies have identified several cortical regions that show larger BOLD responses during preparation and execution of anti-saccades than pro-saccades. We confirmed this finding with a greater BOLD response for anti-saccades than pro-saccades during the preparation phase in the FEF, IPS and DLPFC and in the FEF and IPS in the execution phase. We then applied multi-voxel pattern analysis (MVPA) to establish whether different neural populations are involved in the two types of saccade. Pro-saccades and anti-saccades were reliably decoded during saccade execution in all three cortical regions (FEF, DLPFC and IPS) and in IPS during saccade preparation. This indicates neural specialization, for programming the desired response depending on the task rule, in these regions. In a further study tailored for imaging the superior colliculus in the midbrain a similar magnitude BOLD response was observed for pro-saccades and anti-saccades and the two saccade types could not be decoded with MVPA. This was the case both for activity related to the preparation phase and also for that elicited during the execution phase. We conclude that separate cortical neural populations are involved in the task-specific programming of a saccade while in contrast, the SC has a role in response preparation but may be less involved in high-level, task-specific aspects of the control of saccades
Treatment gaps in the implementation of LDL cholesterol control among high- and very high-risk patients in Europe between 2020ā2021: the multinational observational SANTORINI study
Background European data pre-2019 suggest statin monotherapy is the most common approach to lipid management for preventing cardiovascular (CV) events, resulting in only one-fifth of high- and very high-risk patients achieving the 2019 ESC/EAS recommended low-density lipoprotein cholesterol (LDL-C) goals. Whether the treatment landscape has evolved, or gaps persist remains of interest. Methods Baseline data are presented from SANTORINI, an observational, prospective study that documents the use of lipid-lowering therapies (LLTs) in patients ā„18 years at high or very high CV risk between 2020 and 2021 across primary and secondary care settings in 14 European countries. Findings Of 9602 enrolled patients, 9044 with complete data were included (mean age: 65.3 Ā± 10.9 years; 72.6% male). Physicians reported using 2019 ESC/EAS guidelines as a basis for CV risk classification in 52.0% (4706/9044) of patients (overall: high risk 29.2%; very high risk 70.8%). However, centrally re-assessed CV risk based on 2019 ESC/EAS guidelines suggested 6.5% (308/4706) and 91.0% (4284/4706) were high- and very high-risk patients, respectively. Overall, 21.8% of patients had no documented LLTs, 54.2% were receiving monotherapy and 24.0% combination LLT. Median (interquartile range [IQR]) LDL-C was 2.1 (1.6, 3.0) mmol/L (82 [60, 117] mg/dL), with 20.1% of patients achieving risk-based LDL-C goals as per the 2019 ESC/EAS guidelines. Interpretation At the time of study enrolment, 80% of high- and very high-risk patients failed to achieve 2019 ESC/EAS guidelines LDL-C goals. Contributory factors may include CV risk underestimation and underutilization of combination therapies. Further efforts are needed to achieve current guideline-recommended LDL-C goals. Trial registration ClinicalTrials.gov Identifier: NCT04271280. Funding This study is funded by Daiichi Sankyo Europe GmbH, Munich, Germany
Smartphone and wearable detected atrial arrhythmias in Older Adults: Results of a fully digital European Case finding study
Upper- and mid-mantle interaction between the Samoan plume and the Tonga-Kermadec slabs
Mantle plumes are thought to play a key role in transferring heat from the core\u2013mantle
boundary to the lithosphere, where it can significantly influence plate tectonics. On impinging
on the lithosphere at spreading ridges or in intra-plate settings, mantle plumes may generate
hotspots, large igneous provinces and hence considerable dynamic topography. However, the
active role of mantle plumes on subducting slabs remains poorly understood. Here we show
that the stagnation at 660 km and fastest trench retreat of the Tonga slab in Southwestern
Pacific are consistent with an interaction with the Samoan plume and the Hikurangi plateau.
Our findings are based on comparisons between 3D anisotropic tomography images and 3D
petrological-thermo-mechanical models, which self-consistently explain several unique
features of the Fiji\u2013Tonga region. We identify four possible slip systems of bridgmanite in the
lower mantle that reconcile the observed seismic anisotropy beneath the Tonga slab
(VSH4VSV) with thermo-mechanical calculations
Other-Sex Friendships in Late Adolescence: Risky Associations for Substance Use and Sexual Debut?
Adolescentsā friendships with other-sex peers serve important developmental functions, but they may also facilitate engagement in problem behavior. This study examines the unique contributions of other-sex friendships and friendsā behavior to alcohol use, smoking, and initiation of sexual intercourse among late adolescent girls and boys. A total of 320 adolescents (53% girls; 33% racial/ethnic minorities) provided sociometric nominations of friendships annually in grades 10ā12. Friendship networks were derived using social network analysis in each grade. Adolescents and their friends also reported on their alcohol use, smoking, and sexual debut at each assessment. After controlling for demographics, previous problem behavior, and friendsā behavior, other-sex friendships in 10th grade were associated with initiation of smoking among girls over the following year, and other-sex friendships in 11th grade were linked with lower levels of subsequent alcohol use among boys. Additionally, friendsā smoking and sexual experience in 10th grade predicted the same behaviors for all adolescents over the following year. Other-sex friendships thus appear to serve as a risk context for adolescent girlsā smoking and a protective context for adolescent boysā drinking. Promoting mixed-gender activities and friendships among older high school students may be helpful in reducing malesā alcohol use, but may need to incorporate additional components to prevent increases in femalesā smoking
Serum amyloid A primes microglia for ATP-dependent interleukin-1\u3b2 release
Acute-phase response is a systemic reaction to environmental/inflammatory insults and involves production of acute-phase proteins, including serum amyloid A (SAA). Interleukin-1\u3b2 (IL-1\u3b2), a master regulator of neuroinflammation produced by activated inflammatory cells of the myeloid lineage, in particular microglia, plays a key role in the pathogenesis of acute and chronic diseases of the peripheral nervous system and CNS. IL-1\u3b2 release is promoted by ATP acting at the purinergic P2X7 receptor (P2X7R) in cells primed with toll-like receptor (TLR) ligands
Should mechanical dyssynchrony be assessed in patients with implantable cardioverter-defibrillators?
Cardiac Dysfunction and Arrhythmia
The Role of Important Non-Parental Adults (VIPs) in the Lives of Older Adolescents: A Comparison of Three Ethnic Groups
Previous research has consistently documented the importance of VIPs (mentors or important non-parental adults) in the lives of adolescents. Little is known, however, about whether VIPs play the same important roles across ethnic groups and whether VIPs remain influential when adolescents are older and involved in romantic relationships. The present study compared VIPs of 355 Hispanic, Asian, and European American older adolescents (age rangeĀ =Ā 17ā19Ā years; MĀ =Ā 18.7Ā years; 62% female). Results indicated that, despite ethnic differences in their social capital, VIPsā psychological characteristics (e.g., warmth and acceptance, depressive symptoms, and problem behavior) were similar. VIPs were perceived to have more positive psychological profiles than parents and peers, and in some cases, romantic partners. Moreover, with a few exceptions, the associations between VIP characteristics and adolescent adjustment (e.g., self-esteem, depressive symptoms, and problem behavior) were largely similar across ethnic groups. Finally, VIPs made unique contributions to adolescentsā self-esteem and problem behaviors even after the effects of romantic partners were considered. Implications of the findings are discussed
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