The application of molecular techniques for the rapid and sensitive detection of gastrointestinal pathogens directly in food

Conventional microbiological methods are slow, labour intensive and are unable to meet the demands for rapid food testing. Molecular methods, such as PCR, offer a rapid, sensitive and specific means of detecting pathogens, however loss of sensitivity and lack of robustness have been reported when PCR is applied to heterogeneous and complex food matrices. The aim of this study was to establish a rapid, reliable and sensitive molecular method to detect pathogens in food samples. Real-time PCR assays for the detection of Campylobacter jejuni and coli, Clostridium perfringens, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica and Staphylococcus aureus in food enrichment samples were developed. A novel organism was constructed using a gfp gene cloned into the chromosome of a non-pathogenic Escherichia coli. Viable cells of the modified strain were encapsulated in Lenticule discs and used as process control in the PCR assays. MagNA Pure™ automated extraction was shown to be robust and reliable for preparing bacterial DNA from food enrichment broths. The PCR assays and MagNA Pure™ was applied to enrichment broths inoculated with 558 naturally-contaminated food and environmental samples in a field trial. Concordance was found between PCR results and those obtained using standard culture methods. Loss of assay sensitivity or PCR inhibition was detected in 6 % (32) of the enrichment samples. To improve the sensitivity the L monocytogenes hlyA gene PCR was nested. The assay was applied for the sensitive non-cultural diagnosis of listeriosis, with L monocytogenes detected in 15 of 17 clinical samples from patients with suspected listeriosis. In conclusion, these assays provided a high throughput, robust, reliable PCR detection methods that could be used in clinical and food testing laboratories. The methods will be essential in outbreak situations and could be further developed to detecting bacterial pathogens, viruses, parasites, new and emerging pathogens

Generalized pulsating strings

In this paper we consider new solutions for pulsating strings. For this purpose we use tha idea of the generalized ansatz for folded and circular strings in hep-th/0311004. We find the solutions to the resulting Neumann-Rosochatius integrable system and the corrections to the energy. To do that we use the approach developed by Minahan in hep-th/0209047 and find that the corrections are quite different from those obtained in that paper and hep-th/0310188. We conclude with comments on our solutions and obtained corrections to the energy, expanded to the leading order in lambda.Comment: v.2 references added, citations corrected, 18 page

A Stochastic Approach for Investigation Ultrafast Phenomena in Semiconductors

2002 Mathematics Subject Classification: 65C05In this paper a stochastic approach is proposed for investigation the ultrafast evolution of electrons interacting with phonons in the presence of an applied electric field. The quantum-kinetic equation describing the above ultrafast phenomena contains polynomial non-linearity which allows to use the link between non-stationary iterative processes and the branching stochastic processes. The considered stochastic approach relies on the numerical Monte Carlo (MC) theory as applied to the integral form of the quantum-kinetic equation and estimates the electron energy distribution using statistical averages over long evolution times. The numerical tests were performed for GaAs material parameters. The numerical results for the electron energy distribution function in the case of a non-linear electron quantum transport is compared with the obtained results in the linear case.Supported by Center of Excellence BIS-21 grant ICA1-2000-70016 and by the NSF of Bulgaria under Grants # I 811/98 and # MM 902/99

Симптоми на ЛОР органите при пациенти с гастроезофагеална рефлуксна болест (ГЕРБ)

Въведение: Гастроезофагеалната рефлуксна болест (ГЕРБ) се дефинира, като хронично възпаление на долната трета на хранопровода в резултат на връщане на част от стомашното съдържание (а понякога и гастродуоденален рефлукс) към хранопровода и/или в съседни органи (фаринкса, ларинкса, бронхите), което води до променлив спектър от езофагеални и/или извън езофагеални признаци и симптоми, свързани или не с тъканни лезии.Цел: Да се определи разпространението на някои симптоми в ЛОР органите при пациенти с гастро-езофагеална рефлуксна болест (ГЕРБ).Материал и методи: Извършено е проучване на 54 пациенти в продължение на 18 месеца. При всички пациенти са осъществени: стандартно изследване на ЛОР органи; изследвания на гастроинтестинален тракт: горна ендоскопия (по Лос Анджелиската класификация, 2003 г.), контрастна рентгенография на хранопровода и стомаха с Бариев сулфат; pH тест. Резултатите се обработиха в програмата SPSS, версия 10.0.Резултати: Пациентите с типични симптоми на гастроезофагеална рефлуксна болест бяха 48 (88%). При двадесет и седем болни се установиха промени в лигавицата на хранопровода – клас А – 27 (50%), клас Б – 17 (31.5%) и 10 (18.5%) – от класове C + D. При по-тежки степени на езофагити бяха диагностицирани по-изявени симптоми и промени в устната кухина.Заключение: Нашите резултати, както и на други автори потвърждават, че промените в ЛОР органите при болни с ГЕРБ зависят от степентта на възпалителните промени в хранопровода

Data mining: a tool for detecting cyclical disturbances in supply networks.

Disturbances in supply chains may be either exogenous or endogenous. The ability automatically to detect, diagnose, and distinguish between the causes of disturbances is of prime importance to decision makers in order to avoid uncertainty. The spectral principal component analysis (SPCA) technique has been utilized to distinguish between real and rogue disturbances in a steel supply network. The data set used was collected from four different business units in the network and consists of 43 variables; each is described by 72 data points. The present paper will utilize the same data set to test an alternative approach to SPCA in detecting the disturbances. The new approach employs statistical data pre-processing, clustering, and classification learning techniques to analyse the supply network data. In particular, the incremental k-means clustering and the RULES-6 classification rule-learning algorithms, developed by the present authors’ team, have been applied to identify important patterns in the data set. Results show that the proposed approach has the capability automatically to detect and characterize network-wide cyclical disturbances and generate hypotheses about their root cause

A note on spin chain/string duality

Recently a significant progress in matching the anomalous dimensions of certain class of operators in N=4 SYM theory and rotating strings was made. The correspondence was established mainly using Bethe ansatz technique applied to the spin s Heisenberg model. In a recent paper Kruczenski (hep-th/0311203) suggested to solve the Heisenberg model by using of sigme model approach. In this paper we generalize the solutions obtained by Kruczenski and comment on the dual string theory. It turns out that our solutions are related to the so called Neumann-Rosochatius integrable system. We comment on the spin chain solutions and on the string/gauge theory correspondence.Comment: v.2 One reference added, typos corrected, 21 page

How to implement HyGene into ACT-R

We investigate if and how the model of hypothesis generation and probability judgment HyGene can be implemented in ACT-R. We ground our endeavour on the formal comparison of the memory theories behind ACT-R and HyGene, whereby we contrast the predictions of the two as a function of prior history and current context. After demonstrating the convergence of the two memory theories, we provide a 3-step guide of how to translate a memory representation from HyGene into ACT-R. We also outline how HyGene’s processing steps can be translated into ACT-R. We finish with a discussion of points of divergence between the two theories