An Empirical Analysis of Takeover Predictions in the UK: Application of Artificial Neural Networks and Logistic Regression

Merged with duplicate record 10026.1/656 on 27.03.2017 by CS (TIS)This study undertakes an empirical analysis of takeover predictions in the UK. The objectives of this research are twofold. First, whether it is possible to predict or identity takeover targets before they receive any takeover bid. Second, to test whether it is possible to improve prediction outcome by extending firm specific characteristics such as corporate governance variables as well as employing a different technique that has started becoming an established analytical tool by its extensive application in corporate finance field. In order to test the first objective, Logistic Regression (LR) and Artificial Neural Networks (ANNs) have been applied as modelling techniques for predicting target companies in the UK. Hence by applying ANNs in takeover predictions, their prediction ability in target classification is tested and results are compared to the LR results. For the second objective, in addition to the company financial variables, non-financial characteristics, corporate governance characteristics, of companies are employed. For the fist time, ANNs are applied to corporate governance variables in takeover prediction purposes. In the final section, two groups of variables are combined to test whether the previous outcomes of financial and non-financial variables could be improved. However the results suggest that predicting takeovers, by employing publicly available information that is already reflected in the share price of the companies, is not likely at least by employing current techniques of LR and ANNs. These results are consistent with the semi-strong form of the efficient market hypothesis

Target differentiation with simple infrared sensors using statistical pattern recognition techniques

Cataloged from PDF version of article.This study compares the performances of various statistical pattern recognition techniques for the differentiation of commonly encountered features in indoor environments, possibly with different surface properties, using simple infrared (IR) sensors. The intensity measurements obtained from such sensors are highly dependent on the location, geometry, and surface properties of the reflecting feature in a way that cannot be represented by a simple analytical relationship, therefore complicating the differentiation process. We construct feature vectors based on the parameters of angular IR intensity scans from different targets to determine their geometry and/or surface type. Mixture of normals classifier with three components correctly differentiates three types of geometries with different surface properties, resulting in the best performance (100%) in geometry differentiation. Parametric differentiation correctly identifies six different surface types of the same planar geometry, resulting in the best surface differentiation rate (100%). However, this rate is not maintained with the inclusion of more surfaces. The results indicate that the geometrical properties of the targets are more distinctive than their surface properties, and surface recognition is the limiting factor in differentiation. The results demonstrate that simple IR sensors, when coupled with appropriate processing and recognition techniques, can be used to extract substantially more information than such devices are commonly employed for. (C) 2007 Pattern Recognition Society. Published by Elsevier Ltd. All rights reserve

Factors Affecting Recurrent Choledocholithiasis After Endoscopic Biliary Sphincterotomy: A Cross-Sectional Study

Aim:The purpose of this study was to identify and analyze factors associated with the recurrence of common bile duct stones (CBDS) following endoscopic interventions, aiming to provide insights into predictors and characteristics of CBDS recurrence after endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic sphincterotomy (EST) procedures.Methods:The study was designed as a single-center, cross-sectional study. Clinical data were collected from 271 patients with CBDS who underwent ERCP between June 2019 and December 2022. According to the diagnostic criteria for CBDS recurrence, patients were categorized into recurrence and non-recurrence groups. The assessment of predisposing risk factors for recurrent bile duct stones included various variables such as age, sex, gallbladder status, presence of periampullary diverticulum (PAD), number and diameter of bile duct stones, bile duct diameter, pre-cutting, and early complications.Results:A total of 271 patients were included in the study. CBDS recurrence occurred in 25 patients (9.2%), with a median of 18 months after ERCP and EST. Notable findings included that patients with recurrent CBDS had larger common bile duct diameters (7.5±4.5 mm vs 13±1.7 mm, p=0.037). Choledocholithiasis was more common in patients with a choledochal duct diameter ≥1.5 cm (3% vs 48%, p=0.00001). Recurrent choledocholithiasis was frequent in patients with larger stone sizes (7.3±6.5 mm vs 13.5±4.3 mm, p=0.04). The presence of PAD was correlated with a higher recurrence risk (23% vs 44%, p=0.013). The time to stone recurrence after the index ERCP and EST was 18.273±2.021 months. There was no significant difference in recurrence between patients with ≥2 CBDS and those with a single stone (41% vs 44%, p=0.35).Conclusion:Larger bile duct diameter, choledochal stone size, initial stone size, and the presence of PAD emerged as crucial indicators of recurrence risk. These findings contribute to our understanding of the prediction and management of CBDS recurrence after ERCP and EST procedures

Testing robustness of relative complexity measure method constructing robust phylogenetic trees for Galanthus L. Using the relative complexity measure

Background: Most phylogeny analysis methods based on molecular sequences use multiple alignment where the quality of the alignment, which is dependent on the alignment parameters, determines the accuracy of the resulting trees. Different parameter combinations chosen for the multiple alignment may result in different phylogenies. A new non-alignment based approach, Relative Complexity Measure (RCM), has been introduced to tackle this problem and proven to work in fungi and mitochondrial DNA. Result: In this work, we present an application of the RCM method to reconstruct robust phylogenetic trees using sequence data for genus Galanthus obtained from different regions in Turkey. Phylogenies have been analyzed using nuclear and chloroplast DNA sequences. Results showed that, the tree obtained from nuclear ribosomal RNA gene sequences was more robust, while the tree obtained from the chloroplast DNA showed a higher degree of variation. Conclusions: Phylogenies generated by Relative Complexity Measure were found to be robust and results of RCM were more reliable than the compared techniques. Particularly, to overcome MSA-based problems, RCM seems to be a reasonable way and a good alternative to MSA-based phylogenetic analysis. We believe our method will become a mainstream phylogeny construction method especially for the highly variable sequence families where the accuracy of the MSA heavily depends on the alignment parameters

Preoperative detection of insulinomas: two case reports

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

A case of pulmonary aspergillosis in white storks

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗAspergillosis is a fungal infection affecting respiratory system both in mammals and avian species. It is more commonly encountered in birds, in comparison with its mammalian counterpart. Mostly isolated strains are Aspergillus fumigatus (95%) and Aspergillus flavus (5%). Affected lungs and air sacs reveal miliary to gross lesions like gray-yellowish or white-grayish granulomatous foci surrounded by white halos indicative of inflammatory infiltration. Five storks found dead in the rural areas near Istanbul were submitted to our faculty between years 2008 and 2014. Two of them were thought to be younger than 1-year-old and the other three were older than one year of age. Necropsies were performed right after their submissions. Aspergillosis lesions were observed in the lungs and thoracic air sacs of the first four storks. In addition to these changes the lesions were detected at the aortic bifurcation and on the testicular and renal capsule of the fifth stork. Histopathology revealed encapsulated granulomas with foci of caseous necrosis at the center surrounded by numerous macrophages, heterophil leukocytes, lymphocytes and foreign body giant cells in all the storks. Following the gross, histopathological and mycological examinations the agents were detected as Aspergillus fumigatus. Although, the number of reported deaths due to Aspergillosis is not high in storks, we believe that these birds are quite susceptible to the disease and stress factors such as migration increases the risk of pathogenicity. This report was designed as a contribution to literature since there is only one reported case available with respect to aspergillosis associated death in storks and stress factors such as migration may also predispose storks to the disease

Neospora caninum in Aborted Bovine Fetuses in Trakya Region, Turkey - Histopathological, Immunohistochemical and Molecular Detection

Background: Being the major cause of bovine abortion in the world, Neosporosis is considered to be a very important protozoal infection in dairy cattle. Vertical transplacental transmission is the major route of the infection causing either abortion or birth of calves with persistent infection. As the seropositivity in individual cows and in fetal serology only indicate exposure to the protozoa, the diagnosis of the infection has to be based on histopathology of aborted fetuses. Additional techniques such as immunohistochemistry (IHC) and PCR are required for the detection of the etiological agent. The purpose of the current study was to diagnose Neospora caninum infection in aborted bovine fetuses in Trakya Region of Turkey. For this purpose, serological, histopathological, IHC, and PCR methods were used. Materials, Methods & Results: The blood samples and the fetuses of 55 aborted dairy cattle from various farms located in 3 provinces of Trakya, Turkey constituted the material of the present study. The sera obtained from the blood samples were tested using a Neospora caninum Antibody Test Kit cELISA and anti-N. caninum antibodies were detected in the sera of the dams of the 8 aborted fetuses (8/55; 14.54%). Following the necropsy, samples from the brain, heart, liver, lung, kidney, spleen, and placenta of 55 fetuses were routinely processed for histopathological examination and evaluated under a light microscope. Nonsuppurative encephalitis (15/55; 27.27%), necrosis (5/55; 9%) and gliosis (1/55; 1.8%) in the brain, mild to severe nonsuppurative myocarditis and epicarditis (14/55; 25.45%), and portal to mid-zonal nonsuppurative hepatitis (13/55; 23.63%) were the relevant findings. PCR analysis was performed on fresh frozen fetal tissues. Nested PCR detected N. caninum DNA in the brain, heart, liver, lung, and kidney tissues of 6 fetuses (6/55; 10.9%). IHC was performed on the brain, heart, and liver tissues of all the fetuses using avidin-biotin-complex peroxidase method. Immunoreactivity was observed in the brain of 1 fetus (1/55; 1.8%). Discussion: In the present study, histopathological, immunohistochemical and PCR analyses were performed to detect N. caninum in 55 spontenously aborted bovine fetuses in Trakya Region, Turkey. Histopathologic hallmark of the study was nonsuppurative inflammation found mostly in the brain, heart and liver followed by kidneys and lungs. No protozoa was observed in the microscopic examination supporting the fact that definitive diagnosis of N. caninum infection requires ancillary techniques such as IHC and PCR. Nested PCR detected N. caninum DNA in the tissues of 6 fetuses (6/55; 10.9%). Brain was the most reliable organ for detection by PCR (6/6; 100%), compatible with the previous reports. IHC diagnosis revealed only 1.8% positivity in the present study which was remarkably lower than found in the previous studies. Even though histopathology in conjunction with IHC are accepted as the “gold standard” methods to detect N. caninum infection in aborted bovine fetuses, there are studies claiming that IHC is relatively insensitive in the diagnosis of neosporosis as parasite numbers can be low and thus, false negative results can be obtained. Other factors affecting the sensitivity of the technique are thoroughly discussed by many authors. Supportively, the findings of the current study showed that using both IHC and PCR as complementary techniques, increases the success of detection of N. caninum as recommended in previous studies. In conclusion, the present study demonstrated the first molecular diagnosis of Neospora caninum infection in bovine aborted fetuses in Trakya Region of Turkey which has a critical geographical location bordering Europe. Keywords: bovine abortion, protozoal infection, histopathology, immunohistochemistry, PCR, Neospora caninum

Testing robustness of relative complexity measure method constructing robust phylogenetic trees for \u3ci\u3eGalanthus\u3c/i\u3e L. Using the relative complexity measure

Background: Most phylogeny analysis methods based on molecular sequences use multiple alignment where the quality of the alignment, which is dependent on the alignment parameters, determines the accuracy of the resulting trees. Different parameter combinations chosen for the multiple alignment may result in different phylogenies. A new non-alignment based approach, Relative Complexity Measure (RCM), has been introduced to tackle this problem and proven to work in fungi and mitochondrial DNA. Result: In this work, we present an application of the RCM method to reconstruct robust phylogenetic trees using sequence data for genus Galanthus obtained from different regions in Turkey. Phylogenies have been analyzed using nuclear and chloroplast DNA sequences. Results showed that, the tree obtained from nuclear ribosomal RNA gene sequences was more robust, while the tree obtained from the chloroplast DNA showed a higher degree of variation. Conclusions: Phylogenies generated by Relative Complexity Measure were found to be robust and results of RCM were more reliable than the compared techniques. Particularly, to overcome MSA-based problems, RCM seems to be a reasonable way and a good alternative to MSA-based phylogenetic analysis. We believe our method will become a mainstream phylogeny construction method especially for the highly variable sequence families where the accuracy of the MSA heavily depends on the alignment parameters