Good and Bad Uncertainty: Macroeconomic and Financial Market Implications

Does macroeconomic uncertainty increase or decrease aggregate growth and asset prices? To address this question, we decompose aggregate uncertainty into ‘good’ and ‘bad’ volatility components, associated with positive and negative innovations to macroeconomic growth. We document that in line with our theoretical framework, these two uncertainties have opposite impact on aggregate growth and asset prices. Good uncertainty predicts an increase in future economic activity, such as consumption, output, and investment, and is positively related to valuation ratios, while bad uncertainty forecasts a decline in economic growth and depresses asset prices. Further, the market price of risk and equity beta of good uncertainty are positive, while negative for bad uncertainty. Hence, both uncertainty risks contribute positively to risk premia, and help explain the cross-section of expected returns beyond cash flow risk

Low contact resistivity of metals on nitrogen-doped cuprous oxide (Cu 2O) thin-films

Forming low-resistivity contacts on cuprous oxide (Cu[subscript 2]O) is an essential step toward demonstrating its suitability as a candidate solar cell material. We measure the contact resistivity of three noble metals (Au, Ag, and Pd) on sputtered Cu[subscript 2]O thin-films with a range of nitrogen doping levels. Using the circular transmission line model, specific contact resistivity as low as 1.1 × 10[superscript −4] Ω · cm[superscript 2] is measured for Pd contacts on heavily doped Cu[subscript 2]O films. Temperature-dependent current-voltage measurements and X-ray photoemission spectroscopy are used to determine the barrier heights formed at metal/Cu[subscript 2] Ointerfaces. Thermionic emission is observed to dominate for undoped films, whilst field emission dominates for heavily doped films, highlighting the importance of carrier concentration on contact resistivity. Finally, we demonstrate that low contact resistivity can be achieved on heavily doped Cu[subscript 2] films using Earth-abundant metals, such as Cu and Ni.National Science Foundation (U.S.) (Award DMR-0819762)National Science Foundation (U.S.) (Award ECS-0335765)National Science Foundation (U.S.). CAREER (Award ECCS-1150878

A modified minimally invasive osteotomy for hallux valgus enables reduction of malpositioned sesamoid bones

Background: Current minimally invasive distal metatarsal osteotomy for hallux valgus (HV) is V-shaped, which prevents correcting the rotational metatarsal head deformity and reduction of sesamoid bones. We aimed to determine the optimal method for sesamoid bone reduction in HV surgery. Methods: We reviewed the records of 53 patients who underwent HV surgery by a single surgeon from 2017 to 2019 according to one of three techniques: open chevron osteotomy (n=19), minimally invasive V-shaped osteotomy (n=18) and a modified, straight minimally invasive osteotomy (n=16). Sesamoid position was graded using the Hardy and Clapham method based on standing radiographs. Results: Postoperative sesamoid position scores were significantly lower (better) following the modified osteotomy than following open chevron osteotomy and V-shaped osteotomy (1.44±0.81, 3.74±1.48 and 4.61±1.09, respectively, P<0.001); and the mean change in score was greater (P<0.001). Conclusion: Modified minimally invasive osteotomy was superior to the two other techniques, in the correction of HV deformity in all planes, including sesamoid reduction

The Effect of Warfarin Use on Postoperative Outcomes after Femoral Neck Surgery

Introduction: Anticoagulation use in the elderly is common for patients undergoing femoral neck hip surgery. However, its use presents a challenge to balance it with associated comorbidities and benefits for the patients. As such, we attempted to compare the risk factors, perioperative outcomes, and postoperative outcomes of patients who used warfarin preoperatively and patients who used therapeutic enoxaparin. Methods: From 2003 through 2014, we queried our database to determine the cohorts of patients who used warfarin preoperatively and the patients who used therapeutic enoxaparin. Risk factors included age, gender, Body Mass Index (BMI) > 30, Atrial Fibrillation (AF), Chronic Heart Failure (CHF), and Chronic Renal Failure (CRF). Postoperative outcomes were also collected at each of the patients’ follow-up visits, including number of hospitalization days, delays to theatre, and mortality rate. Results: The minimum follow-up was 24 months and the average follow-up was 39 months (range: 24–60 months). In the warfarin cohort, there were 140 patients and 2055 patients in the therapeutic enoxaparin cohort. Number of hospitalization days (8.7 vs. 9.8, p = 0.02), mortality rate (58.7% vs. 71.4%, p = 0.003), and delays to theatre (1.70 vs. 2.86, p < 0.0001) were significantly longer for the anticoagulant cohort than the therapeutic enoxaparin cohort. Warfarin use best predicted number of hospitalization days (p = 0.00) and delays to theatre (p = 0.01), while CHF was the best predictor of mortality rate (p = 0.00). Postoperative complications, such as Pulmonary Embolism (PE) (p = 0.90), Deep Vein Thrombosis (DVT) (p = 0.31), and Cerebrovascular Accidents (CVA) (p = 0.72), pain levels (p = 0.95), full weight-bearing status (p = 0.08), and rehabilitation use (p = 0.34) were similar between the cohorts. Conclusion: Warfarin use is associated with increased number of hospitalization days and delays to theatre, but does not affect the postoperative outcome, including DVT, CVA, and pain levels compared to therapeutic enoxaparin use. Warfarin use proved to be the best predictor of hospitalization days and delays to theatre while CHF predicted mortality rate