Art as an Investment and the Underperformance of Masterpieces

This paper constructs a new data set of repeated sales of artworks and estimates an annual index of art prices for the period 1875-2000. Contrary to earlier studies, we find art outperforms fixed income securities as an investment, though it significantly under-performs stocks in the US. Art is also found to have lower volatility and lower correlation with other assets, making it more attractive for portfolio diversification than discovered in earlier research. There is strong evidence of underperformance of masterpieces, meaning expensive paintings tend to under-perform the art market index. A further study reveals that the underperformance could be consistent with overbidding at auctions. The evidence is mixed on whether the "law of one price" holds in the New York auction market

Identifying Majorana Zero Modes in Vortex Lattices Using Fano Factor Tomography

In this work, we investigate the tunneling characteristics of Majorana zero modes (MZMs) in vortex lattices based on scanning tunneling microscopy measurement. We find that zero bias conductance does not reach the quantized value owing to the coupling between the MZMs. On the contrary, the Fano factor measured in the high voltage regime reflects the local particle-hole asymmetry of the bound states and is insensitive to the energy splitting between them. We propose using spatially resolved Fano factor tomography as a tool to identify the existence of MZMs. In both cases of isolated MZM or MZMs forming bands, there is a spatially resolved Fano factor plateau at one in the vicinity of a vortex core, regardless of the tunneling parameter details, which is in stark contrast to other trivial bound states. These results reveal new tunneling properties of MZMs in vortex lattices and provide measurement tools for topological quantum devices.Comment: 12 pages, 13 figure

Kinematic calibration of Delta robot using distance measurements

This paper deals with kinematic calibration of the Delta robot using distance measurements. The work is mainly placed upon: (1) the error modeling with a goal to classify the source errors affecting both the compensatable and uncompensatable pose accuracy; (2) the full/partial source error identification using a set of distance measurements acquired by a laser tracker; and (3) design of a linearized compensator for real-time error compensation. Experimental results on a prototype show that positioning accuracy of the robot can significantly be improved by the proposed approach

Tolerance design and kinematic calibration of a 4-DOF pick-and-place parallel robot

This paper presents a comprehensive methodology for ensuring the geometric pose accuracy of a 4-DOF high-speed pick-and-place parallel robot having an articulated travelling plate. The process is implemented by four steps: (1) formulation of the error model containing all possible geometric source errors; (2) tolerance design of the source errors affecting the uncompensatable pose accuracy via sensitivity analysis; (3) identification of the source errors affecting the compensatable pose accuracy via a simplified model and distance measurements; and (4) development of a linearized error compensator for real-time implementation. Experimental results show that a tilt angular accuracy of 0.1/100, and a volumetric/rotational accuracy of 0.5 mm/±0.8 deg of the end-effector can be achieved over the cylindrical task workspac

Optimal design of a 2-DOF pick-and-place parallel robot using dynamic performance indices and angular constraints

This paper presents an approach for the optimal design of a 2-DOF translational pick-and-place parallel robot. By taking account of the normalized inertial and centrifugal/Coriolis torques of a single actuated joint, two global dynamic performance indices are proposed for minimization. The pressure angles within a limb and between two limbs are considered as the kinematic constraints to prevent direct and indirect singularities. These considerations together form a multi-objective optimization problem that can then be solved by the modified goal attainment method. A numerical example is discussed. A number of robots designed by this approach have been integrated into production lines for carton packing in the pharmaceutical industry

Nomograms for predicting the overall and cancer-specific survival in patients with non-urothelial carcinoma of the bladder: A population-based study

Non-urothelial carcinoma of the bladder (NUCB) is a relatively rare condition, with limited comprehensive studies conducted to date. This research aims to establish nomograms for forecasting overall survival (OS) and cancer-specific survival (CSS) in NUCB patients. It utilizes data of 2,522 patients from the Surveillance, Epidemiology, and End Results (SEER) database spanning from 2004 to 2015. The effectiveness of these nomograms was assessed using receiver operating characteristic (ROC) curves, calibration curves and decision curve analysis (DCA). Key independent predictors for OS included age, race, marital status, histological variants, grade, T stage, N stage, M stage, radical cystectomy and chemotherapy administration. For CSS, the predictors were similar, encompassing age, sex, marital status, histological variants, grade, T stage, N stage, M stage, radical cystectomy and chemotherapy. The nomograms showed strong predictive accuracy. In the training cohort, the area under the curve (AUC) values were 0.796 (OS) and 0.799 (CSS) at 1-year, 0.807 (OS) and 0.824 (CSS) at 3-year, and 0.807 (OS) and 0.827 (CSS) at 5-year intervals. In the validation cohort, AUC values were 0.798 (OS) and 0.798 (CSS) at 1-year, 0.810 (OS) and 0.826 (CSS) at 3-year, and 0.811 (OS) and 0.825 (CSS) at 5-year intervals, consistently around 0.8. Calibration curves indicated high congruence between predicted and actual probabilities of OS and CSS, while DCA demonstrated the models' substantial clinical utility. Overall, this study successfully developed and validated prognostic nomograms for NUCB, capable of accurately predicting OS and CSS at 1-, 3-, and 5-years, thereby offering valuable support in clinical decision-making and the design of clinical trials

Optimal design of a 2-DOF pick-and-place parallel robot using dynamic performance indices and angular constraints

This paper presents an approach for the optimal design of a 2-DOF translational pick-and-place parallel robot. By taking account of the normalized inertial and centrifugal/Coriolis torques of a single actuated joint, two global dynamic performance indices are proposed for minimization. The pressure angles within a limb and between two limbs are considered as the kinematic constraints to prevent direct and indirect singularities. These considerations together form a multi-objective optimization problem that can then be solved by the modified goal attainment method. A numerical example is discussed. A number of robots designed by this approach have been integrated into production lines for carton packing in the pharmaceutical industry