Uncertainties in constraining low-energy constants from 3^3H β\beta decay

We discuss the uncertainties in constraining low-energy constants of chiral effective field theory from $^3$H $\beta$ decay. The half-life is very precisely known, so that the Gamow-Teller matrix element has been used to fit the coupling $c_D$ of the axial-vector current to a short-range two-nucleon pair. Because the same coupling also describes the leading one-pion-exchange three-nucleon force, this in principle provides a very constraining fit, uncorrelated with the $^3$H binding energy fit used to constrain another low-energy coupling in three-nucleon forces. However, so far such $^3$H half-life fits have only been performed at a fixed cutoff value. We show that the cutoff dependence due to the regulators in the axial-vector two-body current can significantly affect the Gamow-Teller matrix elements and consequently also the extracted values for the $c_D$ coupling constant. The degree of the cutoff dependence is correlated with the softness of the employed NN interaction. As a result, present three-nucleon forces based on a fit to $^3$H $\beta$ decay underestimate the uncertainty in $c_D$. We explore a range of $c_D$ values that is compatible within cutoff variation with the experimental $^3$H half-life and estimate the resulting uncertainties for many-body systems by performing calculations of symmetric nuclear matter.Comment: 9 pages, 11 figures, published version, includes Erratum, which corrects Figs. 2-6 due to the incorrect c_D relation between 3N forces and two-body currents use

Coexistence of spherical states with deformed and superdeformed bands in doubly magic 40-Ca; A shell model challenge

Large scale shell model calculations, with dimensions reaching 10**9, are carried out to describe the recently observed deformed (ND) and superdeformed (SD) bands based on the first and second excited 0+ states of 40-Ca at 3.35-MeV and 5.21-MeV respectively. A valence space comprising two major oscillator shells, sd and pf, can accommodate most of the relevant degrees of freedom of this problem. The ND band is dominated by configurations with four particles promoted to the pf-shell (4p-4h in short). The SD band by 8p-8h configurations. The ground state of 40-Ca is strongly correlated, but the closed shell still amounts to 65%. The energies of the bands are very well reproduced by the calculations. The out-band transitions connecting the SD band with other states are very small and depend on the details of the mixing among the different np-nh configurations, in spite of that, the calculation describes them reasonably. For the in-band transition probabilities along the SD band, we predict a fairly constant transition quadrupole moment Q_0(t)~170 e fm**2 up to J=10, that decreases toward the higher spins. We submit also that the J=8 states of the deformed and superdeformed band are maximally mixed.Comment: 12 pages, 9 figure

Diagnosticand pronostic utility of serum microrna-21 in colorectal cancer

Los microRNAs son estructuras moleculares de 20-22 nucleótidos con actividad post-transcripional que están implicados en la carcinogénesis mediante una regulación genética post-transcripcional. Presentamos un estudio prospectivo donde se determina la expresión sérica de microRNA-21 en pacientes con diagnóstico de adenocarcinoma de colon. MATERIAL Y MÉTODOS. Estudio de cohorte prospectivo de al menos 100 pacientes con diagnóstico de adenocarcinoma de colon, y de al menos 60 pacientes con apendicitis aguda como grupo control. Se realizó el análisis de microRNA-21 sérico mediante PCR de las muestras sanguíneas de los pacientes obtenidas de forma preoperatoria. RESULTADOS. La comparación de la expresión del microRNA-21 sérico fue mayor en los pacientes con cáncer colorrectal que en los pacientes del grupo control, siendo el área bajo la curva de 0,603. En el análisis univariante, la expresión del miR- 21 se relaciona de forma estadísticamente significativa con la recidiva local (p=0,025) y con la mortalidad (p=0,029). En el análisis multivariante también se puso de manifiesto que las expresiones mayores (sobreexpresiones) de miR-21 se relacionaban con una reducción del riesgo derecidiva del 51%, mientras que dicha sobreexpresión se relacionaba con una reducción de mortalidad del 50%. CONCLUSIONES. La expresión del microRNA-21 sérico podría ser considerado como un potencial marcador diagnóstico para el cáncer colorrectal. La expresión sérica del microRNA-21 se correlaciona con la recidiva y mortalidad en el cáncer colorrectal. Nuestros resultados sugieren que el miR-21 sérico es un prometedor marcador diagnóstico y pronóstico, y pone de manifiesto su potencial utilidad clínica en el cáncer colorrectalMicroRNAs (miRNAs) are small, noncoding RNAs that are involved in carcinogenesis through postranscriptional gene regulatory activity. Few studies have focused on the detection of miR-21 in serum rather than in tissue. The current study aimed to measure serum miR-21 expression levels and to evaluate their association with the outcome of colorectal cancer (CRC). METHODS. Blood samples were collected from almost 100 CRC patients undergoing surgery with curative intent, and almost 60 control patients. The expression levels of miR-21 were measured using a quantitative reverse transcription polymerase chain reaction (qRT-PCR). RESULTS. Serum microRNA-21 expression was higher in colorectal cancer patients than in control patients, with a ROC curve of 0.603. A univariate analysis revealed that lower expression levels of serum miR-21 were associated with higher local recurrence (p=0.025) and mortality (p=0.029). A logistic regression analysis demonstrated that the relative overexpression of miR-21 (expression >1) was associated with a 51% reduction in the risk of recurrence. A Cox regression analysis identified that a relative increase in miR-21 expression (>1) was associated with a 50% reduction in the risk of mortality CONCLUSIONS. Serum microRNA-21 expression could be considered as a potential diagnostic marker for colorectal cancer. The expression level of serum miR-21 correlates with the recurrence and mortality of CRC patients. Our results suggest that circulating serum miR-21 is a promising diagnostic and prognostic tumour marker, and they highlight the potential clinical utility of miR-21 in colorectal cancerEl presente estudio ha sido financiado con la ayuda otorgada por la Fundación para la Investigación Sanitaria en Castilla La Mancha (FISCAM) y por la Fundación Mutua Madrileña Investigación Médic

Colorectal cancer carcinogenesis

El cáncer colorrectal representó en el año 2008 el tercer tumor más diagnosticado en España, siendo la segunda neoplasia que causó más fallecimientos. El conocimiento del proceso carcinogenético de este tipo de enfermedad permitirá el descubrimiento de nuevas terapéuticas que conlleven menores tasas de incidencia y mortalidad. El continuo avance en la enfermedad tumoral hace que esta revisión sea una puesta al día en el conocimiento de la carcinogénesis del cáncer colorrectalIn 2008, colorectal cancer represented the third most commonly diagnosed tumor in Spain, and the second tumor that caused more deaths. Knowledge of the carcinogenetic process of this disease will allow the discovery of new therapies involving lower rates of incidence and mortality. The continuous progress in tumor disease makes this review an update on the knowledge of colorectal cancer carcinogenesi

Diversifying focused testing for unit testing

Software changes constantly because developers add new features or modifications. This directly affects the effectiveness of the testsuite associated with that software, especially when these new modifications are in a specific area that no test case covers. This paper tackles the problem of generating a high quality test suite to cover repeatedly a given point in a program, with the ultimate goal of exposing faults possibly affecting the given program point. Both search based software testing and constraint solving offer ready, but low quality, solutions to this: ideally a maximally diverse covering test set is required whereas search and constraint solving tend to generate test sets with biased distributions. Our approach, Diversified Focused Testing (DFT), uses a search strategy inspired by GödelTest. We artificially inject parameters into the code branching conditions and use a bi-objective search algorithm to find diverse inputs by perturbing the injected parameters, while keeping the path conditions still satisfiable. Our results demonstrate that our technique, DFT, is able to cover a desired point in the code at least 90% of the time. Moreover, adding diversity improves the bug detection and the mutation killing abilities of the test suites. We show that DFT achieves better results than focused testing, symbolic execution and random testing by achieving from 3% to 70% improvement in mutation score and up to 100% improvement in fault detection across 105 software subjects

Dark-matter-nucleus scattering in chiral effective field theory

Chiral effective field theory allows one to calculate the response of few-nucleon systems to external currents, both for currents that can be probed in the Standard Model and ones that only exist in Standard-Model extensions. In combination with state-of-the-art many-body methods, the constraints from chiral symmetry can then be implemented in nuclear structure factors that describe the response of atomic nuclei in direct-detection searches for dark matter. We review the present status of this approach, including the role of coherently enhanced two-body currents, the discrimination of dark matter candidates based on the nuclear response functions, and limits on Higgs-portal dark matter