122 research outputs found

    Hidden Markov Models for Stock Market Prediction

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    The stock market presents a challenging environment for accurately predicting future stock prices due to its intricate and ever-changing nature. However, the utilization of advanced methodologies can significantly enhance the precision of stock price predictions. One such method is Hidden Markov Models (HMMs). HMMs are statistical models that can be used to model the behavior of a partially observable system, making them suitable for modeling stock prices based on historical data. Accurate stock price predictions can help traders make better investment decisions, leading to increased profits. In this article, we trained and tested a Hidden Markov Model for the purpose of predicting a stock closing price based on its opening price and the preceding day's prices. The model's performance has been evaluated using two indicators: Mean Average Prediction Error (MAPE), which specifies the average accuracy of our model, and Directional Prediction Accuracy (DPA), a newly introduced indicator that accounts for the number of fractional change predictions that are correct in sign

    A survey on the occurrence of ochratoxin A in feeds and sera collected in conventional and organic poultry farms in Northern Italy

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    A survey has been conducted on conventional and organic poultry farms located in northern Italy in order to investigate the occurrence of ochratoxin A (OTA) in feeds and sera in 2006. Ten poultry farms were monitored by taking 20 samples of feed and 94 samples of blood. OTA was assessed through immunoaffinity column purification and HPLC analysis. For in-house validation, recovery experiments, carried out on the spiked samples in the range of 1.0-10.0 μg OTA kg-1 and 0.3-3.0 ng OTA ml-1 for the feed and serum samples, respectively, led to overall recovery averages of 80.6% (RDS=7.3%, n=9) and 83.3% (RDS=3.1%, n=9), respectively. All the feed samples were contaminated by OTA with values ranging from 0.04 to 6.50 μg kg-1. Fiftythree percent of the sera samples were positive, with values ranging from 0.003- 0.165 ng ml-1. None of the feed samples was above the limits set by the European Union on OTA contamination in poultry feeds. No statistically significant differences in OTA contamination of feed or sera were observed either between the organic vs conventional group or between the laying hens vs broiler group

    Periprosthetic knee infection: treatment options

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    Infection is one of the most catastrophic complication following total knee arthroplasty (TKA) and represents the second most common cause of TKA failure. Treatment of a patient with periprosthetic joint infection (PJI) could require often costly and prolonged hospital stays, weeks or months of antibiotic therapy, and multiple surgical procedures. The best management is still highly debating, whereas many treatment options are available. These include suppressive antibiotics, arthroscopic irrigation and debridement, open debridement with insert exchange, single-stage reimplantation and two-stage reimplantation. The choice of the treatment depends on many variables, including integrity of implant, timing of the infection, host factors (age, health, immunologic status), virulence of the infecting organism and wishes of the patient. The aim of this review is to provide a comprehensive understaning of the different options for knee PJIs

    Ecotoxicological evaluation of caffeine and its derivatives from a simulated chlorination step

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    Caffeine is ubiquitous in surface and ground waters and it has been proposed as a marker of the anthropogenic pressure on the environment. Sewage treatment plants based on active sludges seem to be not very efficient in its complete removal from effluents while addnl. disinfection treatments by chlorination are able to do it. In a simulation of the chlorination step herein we report that caffeine is transformed in six byproducts: 8-???chlorocaffeine, 1,???3-???dimethyl-???5-???azabarbituric acid, N,???N'-???dimethylparabanic acid, N,???N'-???dimethyloxalamide, N-???methylurea and N,???N'-???dimethylurea. The ecotoxicity of caffeine and identified compds. was evaluated on the rotifer Brachionus calyciflorus and the alga Pseudokirchneriella subcapitata to assess acute and chronic toxicity, while SOS Chromotest and Ames Test were used to detect the genotoxic potential of the investigated compds. Moreover, we assessed the possible antigenotoxic effect of the selected compds. using SOS Chromotest after co-???incubation with the std. genotoxin, 4-???nitroquinoline 1-???oxide. Chronic exposure to these compds. caused inhibition of growth population on the rotifer while the algae seemed to be unaffected. Results indicated that caffeine (1)???, N,???N'-???dimethyloxamide (4) and N,???N'-???dimethylparabanic acid (5) reduced ??-???galactosidase activity in comparison with pos. control, both at 1 and 5 mg???/L of 4-???NQNO with a good dose-???response

    Genetic traceability of two local chicken populations, Bianca di Saluzzo and Bionda Piemontese, versus some current commercial lines.

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    The aims of this investigation were to analyse the genetic variation of two Piemonte chicken local breeds, Bionda Piemontese and Bianca di Saluzzo, and to set them against some commercial lines. A panel of 19 microsatellite markers was used. On the overall, the results of different analyses highlight the genetic uniqueness of the two breeds; therefore they should be considered genetic resources worthy of preservation. The panel of microsatellites used in this investigation turns out to be a consistent and reliable tool for traceability. In fact, these markers are able to distinguish the two local populations from the commercial lines and they are able to confirm the existence of two genetically different clusters within the Bionda Piemontese, namely the ecotypes standard and Cuneo. Mating policies implemented to avoid inbreeding and, if necessary, a marker assisted conservation scheme would be sufficient to solve the problem of inbreeding
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