Contractor-Renormalization approach to frustrated magnets in magnetic field

We propose to use the Contractor Renormalization (CORE) technique in order to derive effective models for quantum magnets in a magnetic field. CORE is a powerful non-perturbative technique that can reduce the complexity of a given microscopic model by focusing on the low-energy part. We provide a detailed analysis of frustrated spin ladders which have been widely studied in the past: in particular, we discuss how to choose the building block and emphasize the use of their reduced density matrix. With a good choice of basis, CORE is able to reproduce the existence or not of magnetization plateaux in the whole phase diagram contrary to usual perturbation theory. We also address the issue of plateau formation in two-dimensional bilayers and point out the analogy between non-frustrated strongly anisotropic models and frustrated SU(2) ones.Comment: 13 pages, 20 figures; published version with minor change

Effective Theory of Magnetization Plateaux in the Shastry-Sutherland Lattice

We use the non-perturbative Contractor-Renormalization method (CORE) in order to derive an effective model for triplet excitations on the Shastry-Sutherland lattice. For strong enough magnetic fields, various magnetization plateaux are observed, e.g. at 1/8, 1/4, 1/3 of the saturation, as found experimentally in a related compound. Moreover, other stable plateaux are found at 1/9, 1/6 or 2/9. We give a critical review of previous works and try to resolve some apparent inconsistencies between various theoretical approaches.Comment: published version with minor change

KJ66 REVAMP

Our team, the jet engineers, set out to find solutions for the obsolete KJ66 model turbine engine used for static testing and RC plane flying. Our goal was to design a more efficient and performance enhanced model that will compete with new models on the market. We found plans for the original model on the John-Tom.com website. The website also has design improvements for certain parts that will improve performance. Using that as our basis, our team modeled the turbine engine using a computer-aided design program called CATIA. Through this model we changed the turbine stator vanes so that they are now removable instead of welded. This improves maintenance and is cost efficient because of how simple it is to remove a selected stator vane when it is damage. The team incorporated hydrodynamic bearings instead of ball bearings for performance under operating speeds of over 100,000 RPM. The cowl was a simple improvement that most model engines had but was not in the plan sheets. Electrical components such as the full authority digital engine control are stored inside the cowl and it improves aerodynamic properties of the engine when mounted outside of RC airplanes. Mounting brackets and exhaust cone struts were also incorporated into our model. Materials were selected based on properties such as heat resistance, strength, and price. Upon completion of modeling and adding materials we completed our model successfully with a price of only $1081.89 and other models on the market going for as little as$2000

Adapting to the new normal: The process of relational change after stroke within romantic dyads

Brain injury can introduce serious life changes for the survivor and those responsible for care. Stroke, a specific form of brain injury, has been shown to impact communication (e.g., Fridriksson, Fillmore, Guo, & Rorden, 2015) and alter behavior (e.g., Fann, Uomoto, & Katon, 2000), both of which have individual and relational consequences (see Anderson & Keating, 2017). The current study extends the literature on life after stroke by highlighting the shared experiences of relational partners post-stroke. For this study, I gathered sensitizing concepts from the uncertainty in illness theory (Mishel, 1988), the uncertainty management theory (Brashers, 2001), and relational turbulence theory (Solomon, Knobloch, Theiss, & McLaren, 2016) to investigate how couples navigated the illness trajectory after a stroke. I focused specifically on the experience of uncertainty and relational changes that individuals associated with the stroke. I utilized the pragmatic iterative approach (Tracy, 2013) to analyze the interviews I collected from 22 stroke survivors and 22 caregiving partners (complete couples N = 20). My results led to a model of relational changes after stroke within romantic dyads that showed couples often experienced a shift in how they saw themselves, their partner, and the relationship after the stroke. Survivors and caregiving partners also reported an ongoing sense of uncertainty that they associated with the stroke. For couples in this study, managing life after stroke involved a process of acceptance and adaptation. These findings challenge existing theory by highlighting the dyadic experience of illness and the similarities between how survivors and their partners navigate life after a stroke. The current study also suggests that more education about stroke in general, and the influence on couples specifically, is needed at the professional and community levels

Natriuretic peptide receptor-C is up-regulated in the intima of advanced carotid artery atherosclerosis

OBJECTIVE: Natriuretic peptide receptor-C (NPR-C/NPR-3) is a cell surface protein involved in vascular remodelling that is up-regulated in atherosclerosis. NPR-C expression has not been well characterized in human carotid artery occlusive lesions. We hypothesized that NPR-C expression correlates with intimal features of vulnerable atherosclerotic carotid artery plaque. METHODS: To test this hypothesis, we evaluated NPR-C expression by immunohistochemistry (IHC) in carotid endarterectomy (CEA) specimens isolated from 18 patients. The grade, location, and co-localization of NPR-C in CEA specimens were evaluated using two tissue analysis techniques. RESULTS: Relative to minimally diseased CEA specimens, we observed avid NPR-C tissue staining in the intima of maximally diseased CEA specimens (65%; p=0.06). Specifically, maximally diseased CEA specimens demonstrated increased NPR-C expression in the superficial intima (61%, p=0.17), and deep intima (138% increase; p=0.05). In the superficial intima, NPR-C expression significantly co-localized with vascular smooth muscle cells (VSMCs) and macrophages. The intensity of NPR-C expression was also higher in the superficial intima plaque shoulder and cap regions, and significantly correlated with atheroma and fibroatheroma vulnerable plaque regions (β=1.04, 95% CI=0.46, 1.64). CONCLUSION: These findings demonstrate significant NPR-C expression in the intima of advanced carotid artery plaques. Furthermore, NPR-C expression was higher in vulnerable carotid plaque intimal regions, and correlate with features of advanced disease. Our findings suggest that NPR-C may serve as a potential biomarker for carotid plaque vulnerability and progression, in patients with advanced carotid artery occlusive disease

Protection of Ischemic Myocardium by Whole-Body Hypothermia After Coronary Artery Occlusion in Dogs

Anesthetized dogs were cooled to a core body temperature of 26°C or maintained at a body temperature of 37°C during periods of 5 and 10 hours of LAD coronary artery occlusion. Subsequent macroscopic dehydrogenase enzyme mapping showed that ischemic injury was 25 per cent less after 5 hours of coronary occlusion and 20 per cent less after 10 hours of occlusion in hypothermic dogs than in normothermic controls. The heart rate and left ventricular minute work in hypothermic dogs decreased to roughly half the levels measured in normothermic animals, while left ventricular contractility was 10 to 40 per cent lower in hypothermic dogs than in normothermic dogs. However, cardiac index and left ventricular end-diastolic pressure were unchanged by whole body cooling. Thus, hypothermia appeared to diminish the oxygen requirements of the ischemic myocardium without reducing the performance of the heart as a pump. Hypothermia may be useful as a therapeutic adjunct to myocardial revascularization or pharmacologrc interventions