Nature of quantum recurrences in coupled higher dimensional systems

We investigate recurrence phenomena in coupled two degrees of freedom systems. It is shown that an initial well localized wave packet displays recurrences even in the presence of coupling in these systems. We discuss the interdependence of these time scales namely, classical period and quantum revival time, and explain significance of initial conditions

Evaluation of two frequency of collection of apitoxin extracted of hives of Apis mellifera L. time during the summertime in the Region of the Araucania.

El experimento se llevó a cabo desde el 7 de enero al 9 de marzo del 2006, en el Apiario del Centro Experimental Pillanlelbún de la Universidad Católica de Temuco, ubicado a 15 km al norte de Temuco, Región de La Araucanía, Chile. En este lugar se evaluó la producción de apitoxina extraída de colmenas Apis mellifera (Hymenoptera:Apidae). Para la realización del experimento se contó con extractores de apitoxina del tipo canadiense, los que funcionan a través de electroestimulación. Se utilizaron tres colmenas para cada tratamiento y se evaluaron dos frecuencias de extracción diferentes, cada 20 días (T1) y cada 30 días (T2). Las variables analizadas fueron: efecto en el peso de las colonias, mortalidad de abejas y cantidad de apitoxina extraída. No se encontraron diferencias significativas entre las variables estudiadas (peso colonias p = 0,127; mortalidad de abejas p = 0,827; y cantidad de apitoxina p = 0,507), por lo cual se concluye que es recomendable realizar extracciones cada 30 días en comparación a las extracciones cada 20 días, pues es preferible realizar esta operación más distanciada en el tiempo a fin de disminuir costos de operación y molestias a las abejas.The experiment was carried out from 07 January to 09 March 2006 in the Apiary of the Pillanlelbún Experimental Centre of the Catholic University of Temuco, located 15 km north of Temuco, Araucania Region, Chile. Here the production of apitoxin extracted from the hives of Apis mellifera (Hymenoptera:Apidae) was evaluated. The experiment was carried out using apitoxin extractors of a Canadian type which function by electro-stimulation. Three hives were used for each treatment and different extraction frequencies were evaluated: every 20 days (T1) and every 30 days (T2). The variables analysed were: effect on the weight of the colonies, bee mortality and quantity of apitoxin extracted. No significant differences were found between the variables studied (weight colonies p = 0.127, bee mortality p = 0.827, and amount of bee venom p = 0.507)and it was therefore concluded that its is recommended to carry out extractions every 30 days rather than every 20 days, since it is preferable to do this operation at longer time intervals in order to reduce operation costs and disturbance of the bees

Interference spectroscopy with coherent anti-Stokes Raman scattering of noisy broadband pulses

We propose a new technique for comparing two Raman active samples. The method employs optical interference of the signals generated via coherent anti-Stokes Raman scattering (CARS) of broadband laser pulses with noisy spectra. It does not require spectrally resolved detection, and no prior knowledge about either the Raman spectrum of the samples, or the spectrum of the incident light is needed. We study the proposed method theoretically, and demonstrate it in a proof-of-principle experiment on Toluene and ortho-Xylene samples.Comment: 15 pages, 6 figure

Sparse Proteomics Analysis - A compressed sensing-based approach for feature selection and classification of high-dimensional proteomics mass spectrometry data

Background: High-throughput proteomics techniques, such as mass spectrometry (MS)-based approaches, produce very high-dimensional data-sets. In a clinical setting one is often interested in how mass spectra differ between patients of different classes, for example spectra from healthy patients vs. spectra from patients having a particular disease. Machine learning algorithms are needed to (a) identify these discriminating features and (b) classify unknown spectra based on this feature set. Since the acquired data is usually noisy, the algorithms should be robust against noise and outliers, while the identified feature set should be as small as possible. Results: We present a new algorithm, Sparse Proteomics Analysis (SPA), based on the theory of compressed sensing that allows us to identify a minimal discriminating set of features from mass spectrometry data-sets. We show (1) how our method performs on artificial and real-world data-sets, (2) that its performance is competitive with standard (and widely used) algorithms for analyzing proteomics data, and (3) that it is robust against random and systematic noise. We further demonstrate the applicability of our algorithm to two previously published clinical data-sets

Serum amino acid profiles and their alterations in colorectal cancer

Mass spectrometry-based serum metabolic profiling is a promising tool to analyse complex cancer associated metabolic alterations, which may broaden our pathophysiological understanding of the disease and may function as a source of new cancer-associated biomarkers. Highly standardized serum samples of patients suffering from colon cancer (n=59) and controls (n=58) were collected at the University Hospital Leipzig. We based our investigations on amino acid screening profiles using electrospray tandem-mass spectrometry. Metabolic profiles were evaluated using the Analyst 1.4.2 software. General, comparative and equivalence statistics were performed by R 2.12.2. 11 out of 26 serum amino acid concentrations were significantly different between colorectal cancer patients and healthy controls. We found a model including CEA, glycine, and tyrosine as best discriminating and superior to CEA alone with an AUROC of 0.878 (95% CI 0.815-0.941). Our serum metabolic profiling in colon cancer revealed multiple significant disease-associated alterations in the amino acid profile with promising diagnostic power. Further large-scale studies are necessary to elucidate the potential of our model also to discriminate between cancer and potential differential diagnoses. In conclusion, serum glycine and tyrosine in combination with CEA are superior to CEA for the discrimination between colorectal cancer patients and control

Pancreatic carcinoma, pancreatitis, and healthy controls: metabolite models in a three-class diagnostic dilemma

Metabolomics as one of the most rapidly growing technologies in the "-omics” field denotes the comprehensive analysis of low molecular-weight compounds and their pathways. Cancer-specific alterations of the metabolome can be detected by high-throughput mass-spectrometric metabolite profiling and serve as a considerable source of new markers for the early differentiation of malignant diseases as well as their distinction from benign states. However, a comprehensive framework for the statistical evaluation of marker panels in a multi-class setting has not yet been established. We collected serum samples of 40 pancreatic carcinoma patients, 40 controls, and 23 pancreatitis patients according to standard protocols and generated amino acid profiles by routine mass-spectrometry. In an intrinsic three-class bioinformatic approach we compared these profiles, evaluated their selectivity and computed multi-marker panels combined with the conventional tumor marker CA19-9. Additionally, we tested for non-inferiority and superiority to determine the diagnostic surplus value of our multi-metabolite marker panels. Compared to CA19-9 alone, the combined amino acid-based metabolite panel had a superior selectivity for the discrimination of healthy controls, pancreatitis, and pancreatic carcinoma patients $$[ {\text{volume under ROC surface}}\;\left( {\text{VUS}} \right) = 0. 8 9 1 { }\left( { 9 5\,\% {\text{ CI }}0. 7 9 4- 0. 9 6 8} \right)].$$ We combined highly standardized samples, a three-class study design, a high-throughput mass-spectrometric technique, and a comprehensive bioinformatic framework to identify metabolite panels selective for all three groups in a single approach. Our results suggest that metabolomic profiling necessitates appropriate evaluation strategies and—despite all its current limitations—can deliver marker panels with high selectivity even in multi-class setting

Decoherence of molecular wave packets in an anharmonic potential

The time evolution of anharmonic molecular wave packets is investigated under the influence of the environment consisting of harmonic oscillators. These oscillators represent photon or phonon modes and assumed to be in thermal equilibrium. Our model explicitly incorporates the fact that in the case of a nonequidistant spectrum the rates of the environment induced transitions are different for each transition. The nonunitary time evolution is visualized by the aid of the Wigner function related to the vibrational state of the molecule. The time scale of decoherence is much shorter than that of dissipation, and gives rise to states which are mixtures of localized states along the phase space orbit of the corresponding classical particle. This behavior is to a large extent independent of the coupling strength, the temperature of the environment and also of the initial state.Comment: 7 pages, 4 figure

Quantum Revivals in Periodically Driven Systems close to nonlinear resonance

We calculate the quantum revival time for a wave-packet initially well localized in a one-dimensional potential in the presence of an external periodic modulating field. The dependence of the revival time on various parameters of the driven system is shown analytically. As an example of application of our approach, we compare the analytically obtained values of the revival time for various modulation strengths with the numerically computed ones in the case of a driven gravitational cavity. We show that they are in very good agreement.Comment: 14 pages, 1 figur