The size anomaly in the London Stock Exchange: an empirical investigation

This study tests the size effect in the London Stock Exchange, using data for all nonfinancial listed firms from January 1985 to December 1995. The initial tests indicate that average stock returns are negatively related to firm size and that small firm portfolios earn returns in excess of the market risk. Further, the study tests whether the size effect is a proxy for variables such as the Book-to- Market Value and the Borrowing Ratio, as well as the impact of the dividend and the Bid- Ask spread on the return of the extreme size portfolios. The originality of this study is in the application of the Markov Chain Model to testing the Random Walk and Bubbles hypotheses, and the Vector Autoregression (VAR) framework for testing the relationship of macroeconomic variables with size portfolio returns

The development of a position-sensitive CZT detector with orthogonal co-planar anode strips

We report on the simulation, construction, and performance of prototype CdZnTe imaging detectors with orthogonal coplanar anode strips. These detectors employ a novel electrode geometry with non-collecting anode strips in one dimension and collecting anode pixels, interconnected in rows, in the orthogonal direction. These detectors retain the spectroscopic and detection efficiency advantages of single carrier (electron) sensing devices as well as the principal advantage of conventional strip detectors with orthogonal anode and cathode strips, i.e. an N×N array of imaging pixels are with only 2N electronic channels. Charge signals induced on the various electrodes of a prototype detector with 8×8 unit cells (1×1×5 mm3)are compared to the simulations. Results of position and energy resolution measurements are presented and discussed

Analog processing of signals from a CZT strip detector with orthogonal coplanar anodes

We present the requirements, design, and performance of an analog circuit for processing the non-collecting anode strip signals from a cadmium zinc telluride (CZT) strip detector with orthogonal coplanar anodes. Detector signal simulations and measurements with a prototype are used to define the range of signal characteristics as a function of location of the gamma interaction in the detector. The signals from the non- collecting anode strip electrodes are used to define two of the three spatial coordinates including the depth of interaction, the z dimension. Analog signal processing options are discussed. A circuit to process the signals from the non- collecting anode strips and extract from them the depth of interaction is described. The circuit employs a time-over- threshold (TOT) measurement. The performance of the detector prototype with a preliminary version of this circuit is presented, and future development work is outlined

Energy and position resolution of a CdZnTe gamma-ray detector with orthogonal coplanar anodes

We report on the simulation, construction and performance of prototype CZT imaging detectors employing orthogonal coplanar anodes. These detectors employ a novel electrode geometry with non-collecting anode strips in 1D and collecting anode pixels, interconnected in rows, in the orthogonal dimensions. These detectors retain the spectroscopic and detection efficiency advantages of single carried charge sensing devices as well as the principal advantage of conventional strip detectors with orthogonal anode and cathode strips, i.e. an N X N array of imagin pixels are realized with only 2N electronic channels. Charge signals induced on the various electrodes of a prototype detector with 8 X 8 unit cells are in good agreement with the simulations. The position resolution is about 1 mm in the direction perpendicular to the pixel lines while it is of the order of 100 micrometers in the other direction. Energy resolutions of 0.9 percent at 662 keV, 2.6 percent at 122 keV and 5.7 percent at 60 keV have been obtained at room temperature

Three-dimensional imaging and detection efficiency performance of orthogonal coplanar CZT strip detectors

We report on recent three-dimensional imaging performance and detection efficiency measurements obtained with 5 mm thick prototype CdZnTe detectors fabricated with orthogonal coplanar anode strips. In previous work, we have shown that detectors fabricated using this design achieve both very good energy resolution and sub-millimeter spatial resolution with fewer electronic channels than are required for pixel detectors. As electron-only devices, like pixel detectors, coplanar anode strip detectors can be fabricated in the thickness required to be effective imagers for photons with energies in excess of 500 keV. Unlike conventional double-sided strip detectors, the coplanar anode strip detectors require segmented contacts and signal processing electronics on only one surface. The signals can be processed to measure the total energy deposit and the photon interaction location in three dimensions. The measurements reported here provide a quantitative assessment of the detection capabilities of orthogonal coplanar anode strip detectors

Psychotropic Drug Prescription in Adolescents: A Retrospective Study in a Swiss Psychiatric University Hospital.

This retrospective study aims to evaluate off-label prescriptions and administrations of psychotropic medications in adolescents in a university psychiatric hospital in Switzerland. Data were collected during the entire stays from the electronic database for 76 inpatients in 2008 and 76 inpatients in 2014. Data collected included gender, age, psychiatric diagnosis, duration of hospitalization, and psychotropic drug prescriptions and administrations. A total of 224 psychotropic drugs (mean 2.9 drugs/patient) were prescribed in 2008 and 268 (mean 3.5 drugs/patient) in 2014. Due to the prescriptions of some drugs as required, only 76% of the prescriptions were actually administered in 2008 (mean 2.3 drugs/patient) and 55% in 2014 (mean 1.9 drugs/patient). Antipsychotics were the most frequently prescribed drugs in 2008 (74% of patients) and 2014 (86% of patients). Anxiolytics were also highly prescribed in 2008 (54% of patients) and 2014 (66% of patients), as well as antidepressants in 2008 (30% of patients), but less in 2014 (13% of patients). Overall, 69% of prescriptions were found to be off label in 2008 and 68% in 2014, according to age, diagnosis, dose, or formulation as approved by Swissmedic. The medication classes with the highest rate of off-label prescriptions were antidepressants (100% for both years), antipsychotics (94% in 2008 and 92% in 2014), and hypnotics (67% in 2008 and 100% in 2014). For both study periods, at least one off-label psychotropic drug prescription and administration was recorded in 96% and 79% of the patients, respectively. The high rate of off-label psychotropic drug use strengthens the need for clinical trials to better evaluate the efficacy and safety of these treatments in adolescents

Comprehensive Characterization of Multiferroic BiFeO3 Powder Fabricated by the Hydrothermal Procedure

Bismuth ferrite (BiFeO3) has recently drawn attention due to its outstanding multifunctional properties, as well as for being a lead-free ceramic material. In the current study, BiFeO3 nanoparticles were synthesized by strictly controlled hydrothermal process. High geometric molded particles of a small size and with high degree of purity (99.74 %) were obtained. We used nitrates of bismuth and iron as well as 8M potassium hydroxide as a basis for synthesis. The results of the X-ray diffraction study of the obtained polycrystalline material show single-phase bismuth ferrite that crystallizes with a rhombohedral lattice. Using the Rietveld method it has been determined that the particles of the synthesized powder are in a nanometric range with a particle size of about 30 nm. It was found that all reflec-tions of the obtained bismuth ferrite belong to the rhombohedral α-BiFeO3 phase which crystallizes in the space group R3c (No. 161). In addition, electronic and magnetic properties of BiFeO3 were investigated using combination of experimental and theoretical methods. HRTEM analysis confirmed existence of twin stacking faults, which are responsible for enhanced magnetic properties. EPR measurements suggested existence of electrons trapped by vacancies or defects. It has been pro-posed that Fe3+−OV defect complex could be created at elevated temperatures fol-lowed by formation of trivalent Fe ions, which intensely provide local 3d moments. The magnetic behavior of the synthesized material was studied by means of SQUID device and using a vibrating sample magnetometer (VSM). The temperature dependence of the magnetization shows the antiferomagnetic-paramagnetic phase transition at the temperature of TN = 220K, while below this temperature weak ferro-magnetic behavior has been detected. Theoretical studies were performed using a full potential linearized augmented plane-waves plus local orbital (FP(L)APW+lo) method, based on the density functional theory (DFT). In addition, a structure prediction has been performed and 11 additional BiFeO3 modifications have been pro-posed. In the next stage, an ab initio optimization of predicted structures has been performed and the structure of the γ-phase has been elucidated

Pulse-Shape discrimination with the Counting Test Facility

Pulse shape discrimination (PSD) is one of the most distinctive features of liquid scintillators. Since the introduction of the scintillation techniques in the field of particle detection, many studies have been carried out to characterize intrinsic properties of the most common liquid scintillator mixtures in this respect. Several application methods and algorithms able to achieve optimum discrimination performances have been developed. However, the vast majority of these studies have been performed on samples of small dimensions. The Counting Test Facility, prototype of the solar neutrino experiment Borexino, as a 4 ton spherical scintillation detector immersed in 1000 tons of shielding water, represents a unique opportunity to extend the small-sample PSD studies to a large-volume setup. Specifically, in this work we consider two different liquid scintillation mixtures employed in CTF, illustrating for both the PSD characterization results obtained either with the processing of the scintillation waveform through the optimum Gatti's method, or via a more conventional approach based on the charge content of the scintillation tail. The outcomes of this study, while interesting per se, are also of paramount importance in view of the expected Borexino detector performances, where PSD will be an essential tool in the framework of the background rejection strategy needed to achieve the required sensitivity to the solar neutrino signals.Comment: 39 pages, 17 figures, submitted to Nucl. Instr. Meth.

Computer-aided DSM-IV-diagnostics – acceptance, use and perceived usefulness in relation to users' learning styles

BACKGROUND: CDSS (computerized decision support system) for medical diagnostics have been studied for long. This study was undertaken to investigate how different preferences of Learning Styles (LS) of psychiatrists might affect acceptance, use and perceived usefulness of a CDSS for diagnostics in psychiatry. METHODS: 49 psychiatrists (specialists and non-specialists) from 3 different clinics volunteered to participate in this study and to use the CDSS to diagnose a paper-based case (based on a real patient). LS, attitudes to CDSS and complementary data were obtained via questionnaires and interviews. To facilitate the study, a special version of the CDSS was created, which automatically could log interaction details. RESULTS: The LS preferences (according to Kolb) of the 49 physicians turned out as follows: 37% were Assimilating, 31% Converging, 27% Accommodating and 6% Diverging. The CDSS under study seemed to favor psychiatrists with abstract conceptualization information perceiving mode (Assimilating and Converging learning styles). A correlation between learning styles preferences and computer skill was found. Positive attitude to computer-aided diagnostics and learning styles preferences was also found to correlate. Using the CDSS, the specialists produced only 1 correct diagnosis and the non-specialists 2 correct diagnoses (median values) as compared to the three predetermined correct diagnoses of the actual case. Only 10% had all three diagnoses correct, 41 % two correct, 47 % one correct and 2 % had no correct diagnose at all. CONCLUSION: Our results indicate that the use of CDSS does not guarantee correct diagnosis and that LS might influence the results. Future research should focus on the possibility to create systems open to individuals with different LS preferences and possibility to create CDSS adapted to the level of expertise of the user