Why Do Hedge Funds Stop Reporting Their Performance?

It is well known that the voluntary reporting of hedge funds may cause biases in estimates of their investment returns. But wide disagreements exist in explaining why hedge funds stop reporting to the datagathering services. Academic studies have suggested that poor or failing funds stop reporting while industry analysts suggest that better performing funds cease reporting because they no longer need to attract new capital. Using the TASS dataset, we find that hedge funds’ returns are significantly worse at the end of their reporting live. We then use survival time analysis techniques to examine the funds’ time to failure and changes in the hazard rate (i.e., the probability of failure) over time. We also estimate the effects of funds’ performance, size, and other characteristics on the hazard rate. Consistent with the finding on funds’ returns at the end of their reporting lives, we find that better performing and larger hedge funds have lower hazard rates.

A new approach to radon temporal correction factor based on active environmental monitoring devices

The present study aims to identify novel means of increasing the accuracy of the estimated annual indoor radon concentration based on the application of temporal correction factors to short-term radon measurements. The necessity of accurate and more reliable temporal correction factors is in high demand, in the present age of speed. In this sense, radon measurements were continuously carried out, using a newly developed smart device accompanied by CR-39 detectors, for one full year, in 71 residential buildings located in 5 Romanian cities. The coefficient of variation for the temporal correction factors calculated for combinations between the start month and the duration of the measurement presented a low value (less than 10%) for measurements longer than 7 months, while a variability close to 20% can be reached by measurements of up to 4 months. Results obtained by generalized estimating equations indicate that average temporal correction factors are positively associated with CO2 ratio, as well as the interaction between this parameter and the month in which the measurement took place. The impact of the indoor-outdoor temperature differences was statistically insignificant. The obtained results could represent a reference point in the elaboration of new strategies for calculating the temporal correction factors and, consequently, the reduction of the uncertainties related to the estimation of the annual indoor radon concentration.Acknowledgements: The research is supported by the project ID P_37_229, Contract No. 22/01.09.2016, with the title, Smart Systems for Public Safety through Control and Mitigation of Residential Radon linked with Energy Efficiency Optimization of Buildings in Romanian Major Urban Agglomerations SMART-RAD-EN” of the POC Programme

Transport properties of copper phthalocyanine based organic electronic devices

Ambipolar charge carrier transport in Copper phthalocyanine (CuPc) is studied experimentally in field-effect transistors and metal-insulator-semiconductor diodes at various temperatures. The electronic structure and the transport properties of CuPc attached to leads are calculated using density functional theory and scattering theory at the non-equilibrium Green's function level. We discuss, in particular, the electronic structure of CuPc molecules attached to gold chains in different geometries to mimic the different experimental setups. The combined experimental and theoretical analysis explains the dependence of the mobilityand the transmission coefficient on the charge carrier type (electrons or holes) and on the contact geometry. We demonstrate the correspondence between our experimental results on thick films and our theoretical studies of single molecule contacts. Preliminary results for fluorinated CuPc are discussed.Comment: 18 pages, 16 figures; to be published in Eur. Phys. J. Special Topic

The incommensurate charge-density-wave instability in the extended three-band Hubbard model

The infinite-U three-band Hubbard model is considered in order to describe the CuO_2 planes of the high temperature superconducting cuprates. The charge instabilities are investigated when the model is extended with a nearest-neighbor repulsion between holes on copper d and oxygen p orbitals and in the presence of a long-range Coulombic repulsion. It is found that a first-order valence instability line ending with a critical point is present like in the previously investigated model without long-range forces. However, the dominant critical instability is the formation of incommensurate charge-density-waves, which always occur before the valence-instability critical point is reached. An effective singular attraction arises in the proximity of the charge-density wave instability, accounting for both a strong pairing mechanism and for the anomalous normal state properties.Comment: 15 pages in RevteX. Figures available from M. Grill

Outcome of ATP-based tumor chemosensitivity assay directed chemotherapy in heavily pre-treated recurrent ovarian carcinoma

BACKGROUND: We wished to evaluate the clinical response following ATP-Tumor Chemosensitivity Assay (ATP-TCA) directed salvage chemotherapy in a series of UK patients with advanced ovarian cancer. The results are compared with that of a similar assay used in a different country in terms of evaluability and clinical endpoints. METHODS: From November 1998 to November 2001, 46 patients with pre-treated, advanced ovarian cancer were given a total of 56 courses of chemotherapy based on in-vitro ATP-TCA responses obtained from fresh tumor samples or ascites. Forty-four patients were evaluable for results. Of these, 18 patients had clinically platinum resistant disease (relapse < 6 months after first course of chemotherapy). There was evidence of cisplatin resistance in 31 patients from their first ATP-TCA. Response to treatment was assessed by radiology, clinical assessment and tumor marker level (CA 125). RESULTS: The overall response rate was 59% (33/56) per course of chemotherapy, including 12 complete responses, 21 partial responses, 6 with stable disease, and 15 with progressive disease. Two patients were not evaluable for response having received just one cycle of chemotherapy: if these were excluded the response rate is 61%. Fifteen patients are still alive. Median progression free survival (PFS) was 6.6 months per course of chemotherapy; median overall survival (OAS) for each patient following the start of TCA-directed therapy was 10.4 months (95% confidence interval 7.9-12.8 months). CONCLUSION: The results show similar response rates to previous studies using ATP-TCA directed therapy in recurrent ovarian cancer. The assay shows high evaluability and this study adds weight to the reproducibility of results from different centre

Pancreatic insulinomas – clinical, diagnostical and therapeutical aspects

Introduction. Insulinomas are neuroendocrine tumors with low incidence (1-4 persons per million of general population), and represents 1-2% of total pancreatic neoplasm. Material and methods. The study presents the results of surgical treatment applied to 9 patients diagnosed with pancreatic endocrine tumor (PET) - between 1993 - 2016 in the Departament of surgery Nr.2 The diagnostic management has included a clinical and laboratory examination, (glycemic profile, the glycemic index during hypoglycemic and convulsive crises, glycemic levels after the administration of glucose solutions of 40%, assessment of the level of serum insulin, echography, CT, MRI. Results. The symptomatology is dominated by neuropsychiatric symptoms – 8 (88,8%) cases, adrenergic symptoms – 6 (66,6%) cases, digestive - 5 (55,56%) cases and Cushingoid syndrome 1 (11,1%) case. After evaluating the glycemic profile, the glycemic level of hypoglycemic and convulsions crisis was within 2-3,0mmol; the glycemic level after the administration of glucose solutions of 40% was 3,8-5,5mmol, the level of serum insulin was increased 32,45U/mL, level of C-peptide - 4,6 ng/ml. The elective surgeries included: tumor enucleation in 5 (55,6%) cases, corporeal-caudal pancreatectomy with spleen preservation in 3 (33,33%) cases, corporeal- caudal pancreatectomy with splenectomy in 1 (11,1%) case. Mortality and morbidity perioperative were 0. Conclusion. Delays in diagnosis are caused by a non-specific symptomatology (cardiac, neurological, psychiatric symptoms), the pancreatic enucleoresection being the treatement of election

An Innovative System for Monitoring Radon and Indoor Air Quality

Nowadays, a global trend towards increasing the performance of a building is the reduction in energy consumption. In this respect, for existing residential buildings the most common techniques are the application of a thermal insulation layer to the exterior wall of the building and / or window replacements. Unfortunately, their application without proper education of those involved may have a negative effect on the indoor air quality. The use of a continuous monitoring device can give the owner the ability to understand the impact of his behaviour on indoor air quality and, as such, to adjust his routine in order to maintain the indoor air quality at the desired level. This paper introduces a prototype, called ICA system, for continuous, real-time indoor air quality monitoring. The ICA system presents sensors for monitoring the concentration of radon, CO2, CO, VOCs, as well as meteorological parameters, such as temperature, pressure, and relative humidity. Experiments were performed both in laboratory and in situ conditions for testing and validating the proposed system.This work was supported by the project ID P_37_229, Contract No. 22/01.09.2016, with the title “Smart Systems for Public Safety through Control and Mitigation of Residential Radon linked with Energy Efficiency Optimization of Buildings in Romanian Major Urban Agglomerations SMART-RAD-EN” of the POC Programme

Search for CP violation in D+→K−K+π+D^{+} \to K^{-}K^{+}\pi^{+} decays

A model-independent search for direct CP violation in the Cabibbo suppressed decay $D^+ \to K^- K^+\pi^+$ in a sample of approximately 370,000 decays is carried out. The data were collected by the LHCb experiment in 2010 and correspond to an integrated luminosity of 35 pb$^{-1}$. The normalized Dalitz plot distributions for $D^+$ and $D^-$ are compared using four different binning schemes that are sensitive to different manifestations of CP violation. No evidence for CP asymmetry is found.Comment: 13 pages, 8 figures, submitted to Phys. Rev.