Waltzing peakons and compacton pairs in a cross-coupled Camassa-Holm equation

We consider singular solutions of a system of two cross-coupled Camassa-Holm (CCCH) equations. This CCCH system admits peakon solutions, but it is not in the two-component CH integrable hierarchy. The system is a pair of coupled Hamiltonian partial differential equations for two types of solutions on the real line, each of which separately possesses exp(-|x|) peakon solutions with a discontinuity in the first derivative at the peak. However, there are no self-interactions, so each of the two types of peakon solutions moves only under the induced velocity of the other type. We analyse the `waltzing' solution behaviour of the cases with a single bound peakon pair (a peakon couple), as well as the over-taking collisions of peakon couples and the antisymmetric case of the head-on collision of a peakon couple and a peakon anti-couple. We then present numerical solutions of these collisions, which are inelastic because the waltzing peakon couples each possess an internal degree of freedom corresponding to their `tempo' -- that is, the period at which the two peakons of opposite type in the couple cycle around each other in phase space. Finally, we discuss compacton couple solutions of the cross-coupled Euler-Poincar\'e (CCEP) equations and illustrate the same types of collisions as for peakon couples, with triangular and parabolic compacton couples. We finish with a number of outstanding questions and challenges remaining for understanding couple dynamics of the CCCH and CCEP equations

Acute effect of cigarette smoking on the coronary circulation: Constriction of epicardial and resistance vessels

AbstractObjectives. This study was performed to determine the acute effect of cigarette smoking on proximal and distal epicardial condult and coronary resistance vessels.Background. Cigarette smoking causes constriction of epicardial arteries and a decrease in coronary blood flow in patients with coronary artery disease, despite an increase in myocardial oxygen demand. The role of changes in resistance vessel tone in the acute coronary hemodynamic effect of smoking has not been examined.Methods. Twenty-four long-term smokers were studied during cardiac catheterization after vasoactive medications had been discontinued. The effect of smoking one cigerette 10 to 15 mm long on proximal and distal conduit vessel segments was assessed before and immediately after smoking and at 5, 15 and 30 min after smoking (n = 8). To determine the effect of smoking on resistance vessels, coronary flow velocity was measured in a nonobstructed artery with a 3F intracoronary Doppler catheter before and for 5 min after smoking (n = 8). Eight patients were studied without smoking to control for spontaneous changes in conduit arterial diameter (n = 5) and vessel tone (n = 3).Results. The average diameter of proximal coronary artery segments decreased from 2.56 ± 0.12 mm (mean ± SEM) before smoking to 2.41 ± 0.09 mm 5 min after amoking (−5 ± 2%, p < 0.05). Distal coronary diameter decreased from 1.51 ± 0.07 to 1.39 ± 0.06 mm (−8 ± 2%, p < 0.01). Marked focal vasoconstriction after smoking was observed in two patients. Coronary diameter returned to baseline by 30 min after smoking. There was no change in vessel diameter in control patients. Despite a significant increase in the heart rate-mean arterial pressure product, coronary flow velocity decreased by 7 ± 4% (p < 0.05) and coronary vascular increased by 21 ± 4% (p < 0.01) 5 min after smoking. There was no change in these variables in the control subjects.Conclusions. Smoking causes immediate constrictioin of proximal and distil epicardial coronary arteries and an increase in coronay resistance vessel tone despite an increase in myocardial oxygen demand. These acute coronary hemodynamic effects may contribute to the adverse cardiovascular consequences of cigarette smoking

Effect of adenosine antagonism on metabolically mediated coronary vasodilation in humans

AbstractObjectives. This study was performed io assess the importance of adenosine in mediating metabolic coronary vasodilation during atrial pacing stress in humans.Background. Numerous animal studies have examined the role of adenosine in the regulation of coronary blood flow, with inconsistent results.Methods. The effect of the adenosine antagonist aminophylline (6 mg/kg body weight intravenously) on coronary functional hyperemia during rapid atrial pacing was determined in 12 patients. The extent of inhibition of adenosine vasodilation was assessed using graded intracoronary adenosine infusions before and after aminophylline administration in seven patients. Coronary blood flow changes were measured with a 3F intracoronary Doppler catheter.Results. After aminophylline administration, the increase in coronary flow velocity during adenosine infusions was reduced from 84 ± 48% (mean ± SD) to 21 ± 31% above control values (p < 0.001) at 10 μg/min and from 130 ± 39% to 59 ± 51% above control values (p < 0.001) at 40 μg/min. During rapid atrial pacing under control conditions, coronary blood flow velocity increased by 26 ± 16%. The flow increment during paced tachycardia after aminophylline (23 ± 10%) was unchanged from the control value, despite substantial antagonism of adenosine coronary dilation by aminophylline.Conclusions. These data suggest that adenosine does not play an important role in the regulation of coronary blood flow in response to rapid atrial pacing in humans

Trichostatin A Enhances Gap Junctional Intercellular Communication in Primary Cultures of Adult Rat Hepatocytes

The effects of histone deacetylase inhibitor Trichostatin A (TSA) on connexin (Cx) expression and gap junctional intercellular communication (GJIC) were investigated in primary cultures of adult rat hepatocytes. GJIC was monitored by using the scrape-loading/dye transfer method. Immunoblotting and immunocytochemistry were used to investigate Cx protein levels and localization. Cx gene expression was studied by means of quantitative reverse transcriptase-polymerase chain reaction. TSA increased Cx32 protein levels and affected negatively the Cx26 protein levels. The latter was preferentially located in the cytosol of cultured cells. TSA also promoted the appearance of Cx43 in the nuclear compartment of primary cultured hepatocytes. Overall, this resulted in enhanced GJIC activity. It is important to note that the time of onset of TSA treatment was crucial for the extent of its outcome and that the effects of TSA on Cx protein levels occurred independently of transcriptional changes. TSA differentially affects Cx proteins in primary rat hepatocyte cultures, suggesting distinct regulation and/or distinct roles of the different Cx species in the control of hepatic homeostasis. TSA enhances GJIC between primary cultured rat hepatocytes, an interesting finding supporting its use to further optimize liver-based in vitro models for pharmacotoxicological purpose

Technology-enhanced learning on campus: insights from EUNIS e-Learning Task Force

In 2010 the EUNIS e-Learning Task Force (ELTF) members collaborated on a review of tools and technologies in use across our member institutions. One of the key features of that paper was the use of technology to give off-campus learners, such as distance learners, those undertaking field studies and learners in the workplace a richly supported learning experience. Building on the success of that collaboration, the ELTF members have turned their attention this year to the use of technology on campus. Whilst technology and distance learning go hand in hand, universities are often slower to take advantage of the possibilities offered by technology to enrich the learning that takes place in our lecture theatres and classrooms. The reasons for this are often cultural as much as financial or technical. Drawing on experience from across the EUNIS member nations we take a look at the types of tools, learning resources and learning activities that are being used to enhance the traditional curriculum, promote deeper learning and bridge the learning that takes place inside and outside the classroom. We look at a range of innovative projects and the benefits they have delivered, ways of overcoming the barriers to technology-enhanced learning on campus and we speculate about the role and function of the campus of the future

GG-Strands

A $G$-strand is a map $g(t,{s}):\,\mathbb{R}\times\mathbb{R}\to G$ for a Lie group $G$ that follows from Hamilton's principle for a certain class of $G$-invariant Lagrangians. The SO(3)-strand is the $G$-strand version of the rigid body equation and it may be regarded physically as a continuous spin chain. Here, $SO(3)_K$-strand dynamics for ellipsoidal rotations is derived as an Euler-Poincar\'e system for a certain class of variations and recast as a Lie-Poisson system for coadjoint flow with the same Hamiltonian structure as for a perfect complex fluid. For a special Hamiltonian, the $SO(3)_K$-strand is mapped into a completely integrable generalization of the classical chiral model for the SO(3)-strand. Analogous results are obtained for the $Sp(2)$-strand. The $Sp(2)$-strand is the $G$-strand version of the $Sp(2)$ Bloch-Iserles ordinary differential equation, whose solutions exhibit dynamical sorting. Numerical solutions show nonlinear interactions of coherent wave-like solutions in both cases. ${\rm Diff}(\mathbb{R})$-strand equations on the diffeomorphism group $G={\rm Diff}(\mathbb{R})$ are also introduced and shown to admit solutions with singular support (e.g., peakons).Comment: 35 pages, 5 figures, 3rd version. To appear in J Nonlin Sc

Initiating the dialogue between infant mental health and family therapy: a qualitative inquiry and recommendations

This qualitative study explores infant-family mental health experts' perspectives and experiences regarding the inclusion of infants in the family therapy setting. Infant socioemotional development is relational in nature and evolves in the context of both dyadic attachment relationships and broader multi-person co-parenting systems. Given this, we sought to understand why family therapy interventions involving families with infants rarely include the infant in a triangular or family systemic approach. Interviews were completed by clinical and/or research experts whose work integrates tenets of both infant mental health (IMH) and family theory and therapy. All interviewees brought at least 5 years of expertise and were actively engaged in the field. Interviewees expressed consistent beliefs that infants have a rightful and helpful place in family therapy approaches. They maintained that infants' innate social drive and communicative capacities position them to make meaningful and clinically significant contributions within family and systemic psychotherapy contexts. Noting that infants have remained on the periphery of these practices, experts advocated expansion and greater integration between IMH and family therapy, while preserving each field's distinctive identity. Experts reported that the interplay between IMH and family therapy fields has been uni-directional as family systems concepts are embedded within IMH approaches, but few IMH premises are incorporated in mainstream family therapy practices. The disconnect was attributed to multiple factors, including graduate and professional training and theoretical, clinical, research, and sociocultural barriers, which were mutually reinforcing. Experts also identified clinical gains for both infants and family members when infants were meaningfully included in family interventions. Common ground was identified between the disciplines, with a belief that relationally distressed young children and parents are best served by clinical engagement with their network of relationships. Results call for greater collaboration between disciplines to challenge existing traditions and to more fully include infants in mainstream family therapy. Recommendations for integration of family therapy and IMH in clinical, theoretical, research, training, and sociocultural domains are offered

Clinical Presentation and Angiographic Characteristics of Saphenous Vein Graft Failure After Stenting Insights From the SOS (Stenting Of Saphenous Vein Grafts) Trial

ObjectivesWe sought to compare the clinical presentation and angiographic patterns of saphenous vein graft (SVG) failure after stenting with a paclitaxel-eluting stent (PES) versus a similar bare-metal stent (BMS).BackgroundThe mode of SVG failure after stenting has been poorly characterized.MethodsThe SOS (Stenting Of Saphenous Vein Grafts) trial enrolled 80 patients with 112 lesions in 88 SVGs who were randomized to a BMS or PES. Angiographic follow-up at 12 months was available in 83% of the patients.ResultsBinary angiographic restenosis occurred in 51% (24 of 47) of BMS-treated lesions versus 9% (4 of 43) of PES-treated lesions (p < 0.0001). Graft occlusion occurred in 9 of the 21 SVGs (43%) that failed in the BMS group and in 2 of 4 SVGs (50%) that failed in the PES group. SVG failure after stenting presented as an acute coronary syndrome in 10 of the 24 patients (42%) (7 of those 10 patients presented with non–ST-segment elevation acute myocardial infarction), stable angina in 9 (37%) patients, and without symptoms in 5 (21%) patients. Of the 19 patients (with 20 grafts) who developed symptomatic graft failure, repeat SVG revascularization was successfully performed in all 13 (100%) subtotally obstructed SVGs but was attempted (and successful) in only 1 of 7 (14%) occluded SVGs. Revascularization of a native coronary artery was performed in an additional 4 of 7 (57%) symptomatic patients with an occluded SVG.ConclusionsSVG failure after stenting often presents as acute myocardial infarction and with SVG occlusion. Compared with BMS, PES reduce SVG failure

Equity Premium Predictions with Adaptive Macro Indexes

Fundamental economic conditions are crucial determinants of equity premia. However, commonly used predictors do not adequately capture the changing nature of economic conditions and hence have limited power in forecasting equity returns. To address the inadequacy, this paper constructs macro indexes from large data sets and adaptively chooses optimal indexes to predict stock returns. I find that adaptive macro indexes explain a substantial fraction of the short-term variation in future stock returns and have more forecasting power than both the historical average of stock returns and commonly used predictors. The forecasting power exhibits a strong cyclical pattern, implying the ability of adaptive macro indexes to capture time-varying economic conditions. This finding highlights the importance of using dynamically measured economic conditions to investigate empirical linkages between the equity premium and macroeconomic fundamentals

Circulating microRNAs in sera correlate with soluble biomarkers of immune activation but do not predict mortality in ART treated individuals with HIV-1 infection: A case control study

Introduction: The use of anti-retroviral therapy (ART) has dramatically reduced HIV-1 associated morbidity and mortality. However, HIV-1 infected individuals have increased rates of morbidity and mortality compared to the non-HIV-1 infected population and this appears to be related to end-organ diseases collectively referred to as Serious Non-AIDS Events (SNAEs). Circulating miRNAs are reported as promising biomarkers for a number of human disease conditions including those that constitute SNAEs. Our study sought to investigate the potential of selected miRNAs in predicting mortality in HIV-1 infected ART treated individuals. Materials and Methods: A set of miRNAs was chosen based on published associations with human disease conditions that constitute SNAEs. This case: control study compared 126 cases (individuals who died whilst on therapy), and 247 matched controls (individuals who remained alive). Cases and controls were ART treated participants of two pivotal HIV-1 trials. The relative abundance of each miRNA in serum was measured, by RTqPCR. Associations with mortality (all-cause, cardiovascular and malignancy) were assessed by logistic regression analysis. Correlations between miRNAs and CD4+ T cell count, hs-CRP, IL-6 and D-dimer were also assessed. Results: None of the selected miRNAs was associated with all-cause, cardiovascular or malignancy mortality. The levels of three miRNAs (miRs -21, -122 and -200a) correlated with IL-6 while miR-21 also correlated with D-dimer. Additionally, the abundance of miRs -31, -150 and -223, correlated with baseline CD4+ T cell count while the same three miRNAs plus miR- 145 correlated with nadir CD4+ T cell count. Discussion: No associations with mortality were found with any circulating miRNA studied. These results cast doubt onto the effectiveness of circulating miRNA as early predictors of mortality or the major underlying diseases that contribute to mortality in participants treated for HIV-1 infection