489 research outputs found
Lower survival after coronary artery bypass in patients who had atrial fibrillation missed by widely used definitions
OBJECTIVE: To investigate the impact of limiting the definition of post-coronary artery bypass graft (CABG) atrial fibrillation (AF) to AF/flutter requiring treatment-as in the Society of Thoracic Surgeons\u27 (STS) database- on the association with survival.
PATIENTS AND METHODS: We assessed in-hospital incidence of post-CABG AF in 7110 consecutive isolated patients with CABG without preoperative AF at 4 hospitals (January 1, 2004 to December 31, 2010). Patients with ≥1 episode of post-CABG AF detected via continuous in-hospital electrocardiogram (ECG)/telemetry monitoring documented by physicians were assigned to the following: Group 1, identified as having post-CABG AF in STS data and Group 2, not identified as having post-CABG AF in STS data. Patients without documented post-CABG AF constituted Group 3. Survival was compared via a Cox model, adjusted for STS risk of mortality and accounting for site differences.
RESULTS: Over 7 years\u27 follow-up, 16.0% (295 of 1841) of Group 1, 18.7% (79 of 422) of Group 2, and 7.9% (382 of 4847) of Group 3 died. Group 2 had a significantly greater adjusted risk of death than both Group 1 (hazard ratio [HR]: 1.16; 95% confidence interval [CI], 1.02 to 1.33) and Group 3 (HR: 1.94; 95% CI, 1.69 to 2.22).
CONCLUSIONS: The statistically significant 16% higher risk of death for patients with AF post-CABG missed vs captured in STS data suggests treatment and postdischarge management should be investigated for differences. The historical misclassification of missed patients as experiencing no AF in the STS data weakens the ability to observe differences in risk between patients with and without post-CABG AF. Therefore, STS data should not be used for research examining post-CABG AF
Novel nano-composite multi-layered biomaterial for the treatment of multifocal degenerative cartilage lesions
We report on a 46-year-old athletic patient, previously treated with anterior cruciate ligament reconstruction, with large degenerative chondral lesions of the medial femoral condyle, trochlea and patella, which was successfully treated with a closing-wedge high tibial osteotomy and the implant of a newly developed biomimetic nanostructured osteochondral bioactive scaffold. After 1 year of follow-up the patient was pain-free, had full knee range of motion, and had returned to his pre-operation level of athletic activity. MRI evaluation at 6 months showed that the implant gave a hyaline-like signal as well as a good restoration of the articular surface, with minimal subchondral bone oedema. Subchondral oedema was almost non-visible at 12 months
Shift-Volatility Transmission in East Asian Equity Markets
This paper attempts to provide evidence of "shift-volatility" transmission in the East Asian equity markets. By shift-volatility, we mean the volatility shifts from a low level to a high level, corresponding respectively to tranquil and crisis periods. We examine the interdependence of equity volatilities between Hong-Kong, Indonesia, Japan, Malaysia, the Philippines, Singapore, Thailand and the United States. Our main issue is whether shift-volatility needs to be considered as a regional phenomenon, or from a more global perspective. We find that the timing/spans of high volatility regimes correspond adequately to years historically documented as those of crises (the Asian crisis and the years following the 2008 crisis). Moreover, we suggest different indicators that could be useful to guide the investors in their arbitrage behavior in the different regimes: the duration of each state, the sensitivity of the volatility in a market following a change in the volatility in another market. Finally, we are able to identify which market can be considered as leading markets in terms of volatility
Risk-On/Risk-Off, Capital Flows, Leverage, and Safe Assets
This paper describes the international flow of funds associated with calm and volatile global equity markets. During calm periods, portfolio investment by real money and leveraged investors in advanced countries flows into emerging markets. When central banks in the receiving countries resist exchange rate appreciation and buy dollars against domestic currency, they end up investing in medium-term bonds in reserve currencies. In the process they fund themselves (or "sterilize" the expansion of local bank reserves) by issuing safe assets in domestic currency to domestic investors. Thus, calm periods, marked by leveraged investing in emerging markets, lead to an asymmetric asset swap (risky emerging market assets against safe reserve currency assets) and leveraging up by emerging market central banks. In declining and volatile global equity markets, these flows reverse, and, contrary to some claims, emerging market central banks draw down reserves substantially. In effect emerging market central banks then release safe assets from their reserves, supplying safe havens to global investors
Cornucopia: Temporal safety for CHERI heaps
Use-after-free violations of temporal memory safety continue to plague software systems, underpinning many high-impact exploits. The CHERI capability system shows great promise in achieving C and C++ language spatial memory safety, preventing out-of-bounds accesses. Enforcing language-level temporal safety on CHERI requires capability revocation, traditionally achieved either via table lookups (avoided for performance in the CHERI design) or by identifying capabilities in memory to revoke them (similar to a garbage-collector sweep). CHERIvoke, a prior feasibility study, suggested that CHERI’s tagged capabilities could make this latter strategy viable, but modeled only architectural limits and did not consider the full implementation or evaluation of the approach. Cornucopia is a lightweight capability revocation system for CHERI that implements non-probabilistic C/C++ temporal memory safety for standard heap allocations. It extends the CheriBSD virtual-memory subsystem to track capability flow through memory and provides a concurrent kernel-resident revocation service that is amenable to multi-processor and hardware acceleration. We demonstrate an average overhead of less than 2% and a worst-case of 8.9% for concurrent
revocation on compatible SPEC CPU2006 benchmarks on a multi-core CHERI CPU on FPGA, and we validate Cornucopia against the Juliet test suite’s corpus of temporally unsafe programs. We test its compatibility
with a large corpus of C programs by using a revoking allocator as the system allocator while booting multi-user CheriBSD. Cornucopia is a viable strategy for always-on temporal heap memory safety, suitable for production environments.This work was supported by the Defense Advanced Research Projects Agency (DARPA) and the Air Force Research Laboratory (AFRL), under contracts FA8750-10-C-0237 (“CTSRD”) and HR0011-18-C-0016 (“ECATS”). We also acknowledge the EPSRC REMS Programme Grant (EP/K008528/1), the ABP Grant (EP/P020011/1), the ERC ELVER Advanced Grant (789108), the Gates Cambridge Trust, Arm Limited, HP Enterprise, and Google, Inc
Sticky Prices, Competition and the Phillips Curve
This study analyzes how competition affects price stickiness at the micro level. On the theoretical side, I develop what I call a micro Phillips curve, i.e. a product-specific relation between inflation and economic activity conditional on inflation expectations. I find two opposing effects of competition on the slope of the micro Phillips curve. On the one hand, stronger competition leads to a higher frequency of price revaluations, implying a steeper slope. On the other hand, the stronger competition is, the less firms can transmit changes in economic activity into price changes, implying a flatter slope. Using unique product-level manufacturing panel data, I find that the latter effect clearly dominates and plays an important role in explaining price stickiness. The effect of a marginal increase in economic activity on the likelihood of a price increase is between 63% and 85% lower for products, that face very strong competition, compared to products, that face very weak competition. In line with the theory, prices of products, that face very strong competition, are also less likely to decrease in response to marginal decreases in economic activity. Moreover, it heavily depends on the degree of competition that a product faces whether, and to what extent, the micro Phillips curve is non-linear. The stronger the competition the weaker will be the non-linearity of the micro Phillips curve. My findings imply that effective business cycle policy necessitates good competition policy. Reforms which strengthen the competition in an economy will make stimulus or stabilization policy more effective. Furthermore, the results imply that stimulus or stabilization measures, that target specifically high competition firms or sectors, may be more effective than programs, that follow an indiscriminate all-round principle
The role of platelet rich plasma in musculoskeletal science
The idea of using platelet rich plasma (PRP) in medicine has been around since the 1970s. It is only more recently that its use has been employed in the area of musculoskeletal science. Platelet rich plasma in this area has received much media attention being used by many celebrity sports athletes for musculoskeletal injuries. Therefore it is important for the musculoskeletal practitioner to be aware of the concepts surrounding its use and application. In this article we cover what platelet rich plasma is, how it is prepared and administered, its potential clinical application, and what the current literature discusses in the various areas of musculoskeletal science
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