Renal cell carcinoma: a nomogram for the CT imaging-inclusive prediction of indolent, non-clear cell renal cortical tumours

Aim To develop a nomogram from clinical and computed tomography (CT) data for pre-treatment identification of indolent renal cortical tumours. Patients and methods A total of 1201 consecutive patients underwent dedicated contrast-enhanced CT prior to nephrectomy for a renal cortical tumour between January 2000 and July 2011. Two radiologists evaluated all tumours on CT for size, necrosis, calcification, contour, renal vein invasion, collecting system invasion, contact with renal sinus fat, multicystic tumour architecture, nodular enhancement, and the degree of nephrographic phase enhancement. CT and clinical predictors (gender, body mass index [BMI], age) were incorporated into the nomogram. We employed multivariable logistic regression analysis to predict tumour type and internally validated the final model using the data from reader 1. External validation was performed by using all data from reader 2. We applied Wilcoxon rank sum test and Fisher's exact test to investigate for differences in tumour size, BMI, age, and differences in CT imaging features between patients with aggressive and those with indolent tumours. Results 63.6% (764/1201) of patients had clear-cell or other aggressive non-clear-cell RCC (i.e. papillary RCC type 2, unclassified RCC) and 36.4% (437/1201) had indolent renal cortical tumours (i.e. papillary RCC type 1, chromophobe RCC, angiomyolipoma, or oncocytoma). On CT, indolent tumours were significantly smaller (p < 0.001) than aggressive tumours and significantly associated with well-defined tumour contours (p < 0.001). Aggressive RCC were significantly associated with necrosis, calcification, renal vein invasion, collecting system invasion, contact with renal sinus fat, multicystic tumour architecture, and nodular enhancement (all, p < 0.001). The nomogram's concordance index (C-index) was 0.823 after internal and 0.829 after external validation. Concluding statement We present a nomogram based on 1201 patients combining CT features with clinical data for the prediction of indolent renal cortical tumours. When externally validated, this nomogram resulted in a C-index of 0.829

Links between securities settlement systems: An oligopoly theoretic approach

This paper presents a duopoly model of the securities settlement industry. Because pooling a large amount of payments can help in using liquidity efficiently, issuers prefer systems where a large number of securities are issued. If the central securities depositories establish a mutual link that enables investors to make transactions with foreign securities, cost savings can be achieved. However, these links may have unexpected effects on CSDs’ pricing, and the issuers’ share of the fee burden can increase substantially. It is not advisable to ban additional fees for using the link, as the CSDs might simply increase the fee for domestic transactions.oligopoly, securities settlement systems

The feasibility of through-the-cycle ratings

It has been proposed that the potential procyclicality of Basel II could be alleviated by using through-the-cycle (TTC) ratings in IRBA models. A TTC rating would be based on the structural component of the debtor’s credit risk ignoring cyclical fluctuations. This paper tests for the existence of such fluctuations in corporate sector credit risk and finds vietually no evidence for their existence at the company level. It is not possible to assign satisfactory TTC ratings to debtors if there are no cyclical variations to be filtered out.through-the-cycle rating; credit risk; procyclicality

Interlinking securities settlement systems: a strategic commitment?

Central securities depositories (CSDs) have opened mutual links, but most of them are seldom used. Why are idle links established? By allowing a foreign CSD to offer services through the link the domestic CSD invites competition. The domestic CSD can determine the cost efficiency of the rival by charging suitable fees, and prevent it from becoming more competitive than the domestic CSD. By inviting the competitor the domestic CSD can commit itself not to charge monopoly fees for secondary market services. This enables the domestic CSD to charge high fees in the primary market without violating investors’ participation constraints. JEL Classification: G29, L13access pricing, central securities depositories, network industries, securities settlement systems

Links between securities settlement systems: An oligopoly theoretic approach

This paper presents a duopoly model of the securities settlement industry. Because pooling a large amount of payments can help in using liquidity efficiently, issuers prefer systems where a large number of securities are issued. If the central securities depositories establish a mutual link that enables investors to make transactions with foreign securities, cost savings can be achieved. However, these links may have unexpected effects on CSDs’ pricing, and the issuers’ share of the fee burden can increase substantially. It is not advisable to ban additional fees for using the link, as the CSDs might simply increase the fee for domestic transactions.oligopoly; securities settlement systems

The demand for money market mutual funds

This paper presents a model on the demand for money market funds (MMFs). These funds are a very close substitute for M1 deposits, except that MMFs do not satisfy immediate transaction requirements. The demand for MMFs strengthens when the intended volume of transactions is low. A high interest rate level makes it expensive to hold M1 deposits. High interest rate volatility, paradoxically, increases the risk of holding M1 deposits stronger than the risk of holding MMFs. The results are largely corroborated by Finnish data.money market mutual funds; money demand

Interlinking securities settlement systems: A strategic commitment?

Central securities depositories (CSDs) have opened mutual links, but most of them are seldom used. Why are idle links established? By allowing a foreign CSD to offer services through the link the domestic CSD invites competition. The domestic CSD can determine the cost efficiency of the rival by charging suitable fees, and prevent it from becoming more competitive than the domestic CSD. By inviting the competitor the domestic CSD can commit itself not to charge monopoly fees for secondary market services. This enables the domestic CSD to charge high fees in the primary market without violating investors’ participation constraints.securities settlement systems; central securities depositories; network industries; access pricing

Managers and efficiency in banking

This paper presents evidence on the impact of managers on cost efficiency in banking. Stochastic frontier analysis is applied to a unique Finnish data set. The paper finds that manager age and education have strong yet complicated effects. University education enhances efficiency if the manager is running a large bank. Managing director changes are systematically followed by efficiency changes. Manager retirement typically causes an efficiency improvement, whereas other manager changes can either improve or weaken efficiency.efficiency; banking; managers

Tetramerization in a SU(4)-Heisenberg model on the honeycomb lattice

The SU(4) Heisenberg model can serve as a low energy model of the Mott insulating state in materials where the spins and orbitals are highly symmetric, or in systems of alkaline-earth atoms on optical lattice. Recently, it has been argued that on the honeycomb lattice the model exhibits a unique spin-orbital liquid phase with an algebraic decay of correlations [P. Corboz et al., Phys. Rev. X 2, 041013 (2012)]. Here we study the instability of the algebraic spin-orbital liquid toward spontaneous formation of SU(4) singlet plaquettes (tetramerization). Using a variational Monte Carlo approach to evaluate the projected wave-function of fermions with $\pi$-flux state, we find that the algebraic liquid is robust, and that a finite value of the next nearest exchange is needed to induce tetramerization. We also studied the phase diagram of a model which interpolates between the nearest neighbor Heisenberg model and a Hamiltonian for which the singlet-plaquette product state is an exact ground state.Comment: 10 pages, 11 figure