Magnetohydrodynamic free convection boundary layer Flow of non-Newtonian tangent hyperbolic fluid from a vertical permeable cone with variable temperature

The nonlinear, non-isothermal steady-state boundary layer flow and heat transfer of an incompressible tangent hyperbolic non-Newtonian (viscoelastic) fluid from a vertical permeable cone with magnetic field are studied. The transformed conservation equations are solved numerically subject to physically appropriate boundary conditions using the second-order accurate implicit finite difference Keller-box technique. The numerical code is validated with previous studies. The influence of a number of emerging non-dimensional parameters, namely a Weissenberg number (We), rheological power law index (m), surface temperature exponent (n), Prandtl number (Pr), magnetic parameter (M) suction/injection parameter (fw) and dimensionless tangential coordinate (ξ) on velocity and temperature evolution in the boundary layer regime, is examined in detail. Furthermore, the effects of these parameters on surface heat transfer rate and local skin friction are also investigated. It is observed that velocity, surface heat transfer rate and local skin friction are reduced with increasing Weissenberg number, but temperature is increased. Increasing m enhances velocity and surface heat transfer rate but reduces temperature and local skin friction. An increase in non-isothermal power law index (n) is observed to decrease the velocity and temperature. Increasing magnetic parameter (M) is found to decrease the velocity and increase the temperature. Overall, the primary influence on free convection is sustained through the magnetic body force parameter, M, and also the surface mass flux (injection/suction) parameter, fw. The rheological effects, while still prominent, are not as dramatic. Boundary layers (both hydrodynamic and thermal) are, therefore, most strongly modified by the applied magnetic field and wall mass flux effect. The study is pertinent to smart coatings, e.g., durable paints, aerosol deposition processing and water-based solvent thermal treatment in chemical engineering

Characterization of left and right atrial function in healthy volunteers by cardiovascular magnetic resonance.

BACKGROUND: Left and right atrial function show a different pattern in advanced age in order to maintain adequate ventricular filling. It has been shown that left atrial (LA) function has a prognostic value in a number of heart conditions. Cardiovascular magnetic resonance (CMR) provides high quality images of the left and right atria using high temporal resolution steady state free precession (SSFP) cine sequences. We used SSFP cines to characterize atrial function in healthy, normotensive, volunteers. METHODS: We measured maximum, preatrial contraction and minimum left and right atrial volumes in 120 healthy subjects after careful exclusion of cardiovascular abnormality (60 men, 60 women; 20 subjects per age decile from 20 to 80 years). Data were generated from 3-dimensional modeling, including tracking of the atrioventricular ring motion and time-volume curves analysis. With those measurements, all the usual parameters for left and right atrial function were calculated. RESULTS: Gender had significant influence on some parameters of left and right atrial conduit and booster pump function. Age significantly influenced the majority of parameters of both left and right atrial function, with typically lower reservoir and conduit functions and higher booster pump function, both in males and females belonging to older age groups. CMR normal ranges were modelled for clinical use with normalization, where appropriate, for body surface area and gender, displaying parameters with respect to age. CONCLUSIONS: CMR normal reference ranges for components of left and right atrial function are provided for males and females for a wide age range

Atypical case of post-partum cardiomyopathy: an overlap syndrome with arrhythmogenic right ventricular cardiomyopathy?

A middle-aged female patient presented with increasing dyspnoea following delivery of her second child. Echocardiography showed left ventricular (LV) dilatation and severe global impairment of systolic function (ejection fraction < 10%) but normal right ventricular (RV) dimensions. Plasma B-type natriuretic peptide level was elevated. Post-partum cardiomyopathy (PPCM) was considered and after initiating appropriate heart failure pharmacotherapy, her symptoms improved significantly. Cardiovascular MR showed RV free wall dyskinesia and aneurysms at the LV apex, RV free wall and RV outflow tract. Genetic analysis showed a C11842T substitution in the titin gene (TTN). This is the first case to propose an overlap syndrome of PPCM and arrhythmogenic RV cardiomyopathy.published_or_final_versio

Detection of recent myocardial infarction using native T1 Mapping in a swine model: a validation study

Late gadolinium enhancement (LGE) imaging is the currently the gold standard for in-vivo detection of myocardial infarction. However, gadolinium contrast administration is contraindicated in patients with renal insufficiency. We aim to evaluate the diagnostic sensitivity and specificity of this contrast-free MRI technique, native T1 mapping, in detecting recent myocardial infarction versus a reference histological gold standard. Ten pigs underwent CMR at 2 weeks after induced MI. The infarct size and transmural extent of MI was calculated using native T1 maps and LGE images. Histological validation was performed using triphenyl tetrazolium chloride (TTC) staining in the corresponding ex-vivo slices. The infarct size and transmural extent of myocardial infarction assessed by T1 mapping correlated well with that assessed by LGE and TTC images. Using TTC staining as the reference, T1 mapping demonstrated underestimation of infarct size and transmural extent of infarction. Additionally, there was a slight but not significant difference found in the diagnostic performance between the native T1 maps and LGE images for the location of MI. Our study shows that native T1 mapping is feasible alternative method to the LGE technique for the assessment of the size, transmural extent, and location of MI in patients who cannot receive gadolinium contrast

Review of Journal of Cardiovascular Magnetic Resonance 2014

There were 102 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2014, which is a 6 % decrease on the 109 articles published in 2013. The quality of the submissions continues to increase. The 2013 JCMR Impact Factor (which is published in June 2014) fell to 4.72 from 5.11 for 2012 (as published in June 2013). The 2013 impact factor means that the JCMR papers that were published in 2011 and 2012 were cited on average 4.72 times in 2013. The impact factor undergoes natural variation according to citation rates of papers in the 2 years following publication, and is significantly influenced by highly cited papers such as official reports. However, the progress of the journal’s impact over the last 5 years has been impressive. Our acceptance rate is <25 % and has been falling because the number of articles being submitted has been increasing. In accordance with Open-Access publishing, the JCMR articles go on-line as they are accepted with no collating of the articles into sections or special thematic issues. For this reason, the Editors have felt that it is useful once per calendar year to summarize the papers for the readership into broad areas of interest or theme, so that areas of interest can be reviewed in a single article in relation to each other and other recent JCMR articles. The papers are presented in broad themes and set in context with related literature and previously published JCMR papers to guide continuity of thought in the journal. We hope that you find the open-access system increases wider reading and citation of your papers, and that you will continue to send your quality papers to JCMR for publication

A Study of Concurrency Bugs and Advanced Development Support for Actor-based Programs

The actor model is an attractive foundation for developing concurrent applications because actors are isolated concurrent entities that communicate through asynchronous messages and do not share state. Thereby, they avoid concurrency bugs such as data races, but are not immune to concurrency bugs in general. This study taxonomizes concurrency bugs in actor-based programs reported in literature. Furthermore, it analyzes the bugs to identify the patterns causing them as well as their observable behavior. Based on this taxonomy, we further analyze the literature and find that current approaches to static analysis and testing focus on communication deadlocks and message protocol violations. However, they do not provide solutions to identify livelocks and behavioral deadlocks. The insights obtained in this study can be used to improve debugging support for actor-based programs with new debugging techniques to identify the root cause of complex concurrency bugs.Comment: - Submitted for review - Removed section 6 "Research Roadmap for Debuggers", its content was summarized in the Future Work section - Added references for section 1, section 3, section 4.3 and section 5.1 - Updated citation

Visual ecology of aphids – a critical review on the role of colours in host finding

We review the rich literature on behavioural responses of aphids (Hemiptera: Aphididae) to stimuli of different colours. Only in one species there are adequate physiological data on spectral sensitivity to explain behaviour crisply in mechanistic terms. Because of the great interest in aphid responses to coloured targets from an evolutionary, ecological and applied perspective, there is a substantial need to expand these studies to more species of aphids, and to quantify spectral properties of stimuli rigorously. We show that aphid responses to colours, at least for some species, are likely based on a specific colour opponency mechanism, with positive input from the green domain of the spectrum and negative input from the blue and/or UV region. We further demonstrate that the usual yellow preference of aphids encountered in field experiments is not a true colour preference but involves additional brightness effects. We discuss the implications for agriculture and sensory ecology, with special respect to the recent debate on autumn leaf colouration. We illustrate that recent evolutionary theories concerning aphid–tree interactions imply far-reaching assumptions on aphid responses to colours that are not likely to hold. Finally we also discuss the implications for developing and optimising strategies of aphid control and monitoring

Euphorbia royleana, a botanical pesticide affects ultimobranchial gland of the catfish Heteropneustes fossilis

Heteropneustes fossilis were subjected to high and low doses of the latex of Euphorbia royleana for short-term and long-term exposures, respectively. The blood was analyzed for plasma calcium levels, and the ultimobranchial glands fixed and examined. Serum calcium levels declined after 48 h following short-term exposure, and this decrease continued until the end of the experiment. The ultimobranchial cells exhibited a decrease in the cytoplasmic staining response after 96 h following treatment, and the nuclear volumes slightly decreased. Chronically exposed fish also exhibited a decline in serum calcium levels, but much later, on day 7, again progressively declining until the close of the experiment. Up to day 14 following treatment there was no change in histological structure of the ultimobranchial glands, but then there was a decrease in nuclear volume and the cytoplasm displayed a weak staining response. There was some vacuolization and degeneration.Keywords: Botanicals, calcitonin, calcium, teleos

Effective Rheology of Bubbles Moving in a Capillary Tube

We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur