Quantification of Ultrasound Correlation‐Based Flow Velocity Mapping and Edge Velocity Gradient Measurement

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135662/1/jum201332101815.pd

Arterial elasticity imaging: comparison of finite-element analysis models with high-resolution ultrasound speckle tracking

<p>Abstract</p> <p>Background</p> <p>The nonlinear mechanical properties of internal organs and tissues may be measured with unparalleled precision using ultrasound imaging with phase-sensitive speckle tracking. The many potential applications of this important noninvasive diagnostic approach include measurement of arterial stiffness, which is associated with numerous major disease processes. The accuracy of previous ultrasound measurements of arterial stiffness and vascular elasticity has been limited by the relatively low strain of nonlinear structures under normal physiologic pressure and the measurement assumption that the effect of the surrounding tissue modulus might be ignored in both physiologic and pressure equalized conditions.</p> <p>Methods</p> <p>This study performed high-resolution ultrasound imaging of the brachial artery in a healthy adult subject under normal physiologic pressure and the use of external pressure (pressure equalization) to increase strain. These ultrasound results were compared to measurements of arterial strain as determined by finite-element analysis models with and without a surrounding tissue, which was represented by homogenous material with fixed elastic modulus.</p> <p>Results</p> <p>Use of the pressure equalization technique during imaging resulted in average strain values of 26% and 18% at the top and sides, respectively, compared to 5% and 2%, at the top and sides, respectively, under physiologic pressure. In the artery model that included surrounding tissue, strain was 19% and 16% under pressure equalization versus 9% and 13% at the top and sides, respectively, under physiologic pressure. The model without surrounding tissue had slightly higher levels of strain under physiologic pressure compared to the other model, but the resulting strain values under pressure equalization were > 60% and did not correspond to experimental values.</p> <p>Conclusions</p> <p>Since pressure equalization may increase the dynamic range of strain imaging, the effect of the surrounding tissue on strain should be incorporated into models of arterial strain, particularly when the pressure equalization technique is used.</p

Cardiovascular health screening among South African students

Stress is an unavoidable part of everyday life due to the demands and stressors associated with modern lifestyle. Health risks provoked by this increasingly prevalent condition lead to cardiovascular disease, which ultimately results in a poor health status. Studies have confirmed that there is a correlation between a person’s lifestyle and stress levels: sedentary lifestyles increase the risk of developing various cardiovascular conditions. Improved physical fitness is one of the lifestyle modifications proven to benefit heart health by reducing the effects of stress and its associated threats. The purpose of this study was to compare the heart health of subjects from two further education and training institutes. Institution 1 is a traditional tertiary institution that focuses on lectures, while Institution 2 provides an organised, daily physical training programme in addition to its academic programme. Subjects underwent a non-invasive ViportTM test which measures the cardio stress index (CSI), heart rate (HR), and QRS duration. Additional variables measured included: age, gender, perceived stress level, systolic and diastolic blood pressure and body mass index. Results obtained from the study indicate that students from Institution 1 (n=158) had significantly higher readings (p<0.001) than those from Institution 2 (n=128) on CSI and HR, but significantly lower readings on blood pressure (systolic and diastolic). In theory, this finding may be attributed to the fact that individuals from Institution 1 (training population) follow a set daily physical routine which improves their heart health and decreases stress- related risk.http://www.ajol.info/journal_index.php?jid=153&ab=ajpher

Become the best coach you can be: the role of coach training and coaching experience in workplace coaching quality and quality control

This paper explores whether coach training or coaching experience leads to better coaching quality and quality control. In two large studies, both coaches (N1 = 2267) and personnel managers who book coaches for their company (N2 = 754) answered questions about coaching quality and quality control. The results show that more coach training leads to not only a better self-perceived coaching quality (Study 1) but also a better other-perceived coaching-quality (Study 2); moreover, more coach training positively affects quality control. It is remarkable that coaching experience showed no significant relation regarding other-perceived coaching quality and quality control. Study 2 further revealed that references lead to more recommendations but not to a better coaching quality or quality control. Thus, coach training is an essential factor when selecting organizational coaches. Further research is needed to understand the impact of different approaches to coach trainings on coaching outcomes

Electron Antineutrino Search at the Sudbury Neutrino Observatory

Upper limits on the \nuebar flux at the Sudbury Neutrino Observatory have been set based on the \nuebar charged-current reaction on deuterium. The reaction produces a positron and two neutrons in coincidence. This distinctive signature allows a search with very low background for \nuebar's from the Sun and other potential sources. Both differential and integral limits on the \nuebar flux have been placed in the energy range from 4 -- 14.8 MeV. For an energy-independent \nu_e --> \nuebar conversion mechanism, the integral limit on the flux of solar \nuebar's in the energy range from 4 -- 14.8 MeV is found to be \Phi_\nuebar <= 3.4 x 10^4 cm^{-2} s^{-1} (90% C.L.), which corresponds to 0.81% of the standard solar model 8B \nu_e flux of 5.05 x 10^6 cm^{-2} s^{-1}, and is consistent with the more sensitive limit from KamLAND in the 8.3 -- 14.8 MeV range of 3.7 x 10^2 cm^{-2} s^{-1} (90% C.L.). In the energy range from 4 -- 8 MeV, a search for \nuebar's is conducted using coincidences in which only the two neutrons are detected. Assuming a \nuebar spectrum for the neutron induced fission of naturally occurring elements, a flux limit of Phi_\nuebar <= 2.0 x 10^6 cm^{-2} s^{-1}(90% C.L.) is obtained.Comment: submitted to Phys. Rev.

Introgressive Hybridization of Schistosoma haematobium Group Species in Senegal: Species Barrier Break Down between Ruminant and Human Schistosomes

The file attached is the Published/publisher’s pdf version of the article.Copyright: © 2013 Webster et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

A strategic framework for biodiversity monitoring in South African National Parks

Protected areas are under increasing threat from a range of external and internal pressures on biodiversity. With a primary mandate being the conservation of biodiversity, monitoring is an essential component of measuring the performance of protected areas. Here we present a framework for guiding the structure and development of a Biodiversity Monitoring System (BMS) for South African National Parks (SANParks). Monitoring activities in the organisation are currently unevenly distributed across parks, taxa and key concerns: they do not address the full array of biodiversity objectives, and have largely evolved in the absence of a coherent, overarching framework. The requirement for biodiversity monitoring in national parks is clearly specified in national legislation and international policy, as well as by SANParks’ own adaptive management philosophy. Several approaches available for categorising the multitude of monitoring requirements were considered in the development of the BMS, and 10 Biodiversity Monitoring Programmes (BMPs) were selected that provide broad coverage of higher-level biodiversity objectives of parks. A set of principles was adopted to guide the development of BMPs (currently underway), and data management, resource and capacity needs will be considered during their development. It is envisaged that the BMS will provide strategic direction for future investment in this core component of biodiversity conservation and management in SANParks. Conservation implications: Monitoring biodiversity in protected areas is essential to assessing their performance. Here we provide a coordinated framework for biodiversity monitoring in South African National Parks. The proposed biodiversity monitoring system addresses the broad range of park management plan derived biodiversity objectives

Connecting Land–Atmosphere Interactions to Surface Heterogeneity in CHEESEHEAD19

The Chequamegon Heterogeneous Ecosystem Energy-Balance Study Enabled by a High-Density Extensive Array of Detectors 2019 (CHEESEHEAD19) is an ongoing National Science Foundation project based on an intensive field campaign that occurred from June to October 2019. The purpose of the study is to examine how the atmospheric boundary layer (ABL) responds to spatial heterogeneity in surface energy fluxes. One of the main objectives is to test whether lack of energy balance closure measured by eddy covariance (EC) towers is related to mesoscale atmospheric processes. Finally, the project evaluates data-driven methods for scaling surface energy fluxes, with the aim to improve model–data comparison and integration. To address these questions, an extensive suite of ground, tower, profiling, and airborne instrumentation was deployed over a 10 km × 10 km domain of a heterogeneous forest ecosystem in the Chequamegon–Nicolet National Forest in northern Wisconsin, United States, centered on an existing 447-m tower that anchors an AmeriFlux/NOAA supersite (US-PFa/WLEF). The project deployed one of the world’s highest-density networks of above-canopy EC measurements of surface energy fluxes. This tower EC network was coupled with spatial measurements of EC fluxes from aircraft; maps of leaf and canopy properties derived from airborne spectroscopy, ground-based measurements of plant productivity, phenology, and physiology; and atmospheric profiles of wind, water vapor, and temperature using radar, sodar, lidar, microwave radiometers, infrared interferometers, and radiosondes. These observations are being used with large-eddy simulation and scaling experiments to better understand submesoscale processes and improve formulations of subgrid-scale processes in numerical weather and climate models

Present Status of Inclusive Rare B Decays

We give a status report on inclusive rare B decays, highlighting recent developments and open problems. We focus on the decay modes $B \to X_{s,d} \gamma$, $B \to X_s \ell^+\ell^-$ and $B \to X_s \nu \bar \nu$ and on their role in the search for new physics. Most of the inclusive rare B decays are important modes of flavour physics due to the small hadronic uncertainties. They can be regarded as laboratories to search for new physics. We collect the experimental data already available from CLEO and the $B$ factories BABAR and BELLE. We review the NLL and NNLL QCD calculations of the inclusive decay rates that were recently completed, and discuss future prospects, especially the issue of the charm mass scheme ambiguity. Finally, we analyse the phenomenological impact of these decay modes, in particular on the CKM phenomenology and on the indirect search for supersymmetry. We also briefly discuss direct CP violation in inclusive rare B decays, as well as the rare kaon decays $K^+\to \pi^+\nu\bar{\nu}$ and $K_L \to \pi^0 \nu \bar{\nu}$, which offer complementary theoretically clean information.Comment: 80 pages, 37 figures, latex, references added Invited contribution to Reviews of Modern Physic