The small xx behavior of the gluon structure function from total cross sections

Within a QCD-based eikonal model with a dynamical infrared gluon mass scale we discuss how the small $x$ behavior of the gluon distribution function at moderate $Q^{2}$ is directly related to the rise of total hadronic cross sections. In this model the rise of total cross sections is driven by gluon-gluon semihard scattering processes, where the behavior of the small $x$ gluon distribution function exhibits the power law $xg(x,Q^2)= h(Q^2)x^{-\epsilon}$. Assuming that the $Q^{2}$ scale is proportional to the dynamical gluon mass one, we show that the values of $h(Q^2)$ obtained in this model are compatible with an earlier result based on a specific nonperturbative Pomeron model. We discuss the implications of this picture for the behavior of input valence-like gluon distributions at low resolution scales.Comment: 19 pages, 3 figures; revised version; to appear in Int. J. Mod. Phys.

Elastic scattering and the proton form factor

We compute the differential and the total cross sections for $pp$ scattering using the QCD pomeron model proposed by Landshoff and Nachtmann. This model is quite dependent on the experimental electromagnetic form factor, and it is not totally clear why this form factor gives good results even at moderate transferred momentum. We exchange the eletromagnetic form factor by the asymptotic QCD proton form factor determined by Brodsky and Lepage (BL) plus a prescription for its low energy behavior dictated by the existence of a dynamically generated gluon mass. We fit the data with this QCD inspired form factor and a value for the dynamical gluon mass consistent with the ones determined in the literature. Our results also provide a new determination of the proton wave function at the origin, which appears in the BL form factor.Comment: 10 pages, 2 figures. Submitted to Physics Letters B. Submitted to Phys. Lett.

Development of boron calibration via hybrid comparator method in prompt gamma activation analysis

The prompt gamma activation analysis (PGAA) facility at the Nuclear Engineering Teaching Laboratory at The University of Texas at Austin was utilized to quantify boron concentrations in boron carbide semiconductor films deposited on silicon substrates. Calibration was complicated by the unique and varying sample geometries analyzed. In addition, there was a dearth of solid materials available with quantified boron concentrations having comparable or readily modifiable dimensions to exploit for calibration purposes. Therefore, a novel hybrid comparator method was developed for the quantification of boron utilizing aluminum as an inexpensive and easily machinable reference material. Aluminum samples were manufactured with high tolerances to match the geometry of each sample of interest. Each boron carbide film sample and its congruent aluminum sample were measured in the PGAA system. The measured aluminum responses and relevant nuclear parameters were used to standardize the measurements. A boron standard was created using a procedure derived from a similar approach used by the National Institute of Standards and Technology. Quality control measurements using this standard show that the method provided accuracy to within 5% for boron quantification

Eradication of Candida albicans persister cell biofilm by the membranotropic peptide gH625

Biofilm formation poses an important clinical trouble due to resistance to antimicrobial agents; therefore, there is an urgent demand for new antibiofilm strategies that focus on the use of alternative compounds also in combination with conventional drugs. Drug-tolerant persisters are present in Candida albicans biofilms and are detected following treatment with high doses of amphotericin B. In this study, persisters were found in biofilms treated with amphotericin B of two clinical isolate strains, and were capable to form a new biofilm in situ. We investigated the possibility of eradicating persister-derived biofilms from these two Candida albicans strains, using the peptide gH625 analogue (gH625-M). Confocal microscopy studies allowed us to characterize the persister-derived biofilm and understand the mechanism of interaction of gH625-M with the biofilm. These findings confirm that persisters may be responsible for Candida biofilm survival, and prove that gH625-M was very effective in eradicating persister-derived biofilms both alone and in combination with conventional antifungals, mainly strengthening the antibiofilm activity of fluconazole and 5-flucytosine. Our strategy advances our insights into the development of effective antibiofilm therapeutic approaches

Adubação N-P-K para o abacaxizeiro BRS Imperial para o Extremo Sul da Bahia.

A Embrapa Mandioca e Fruticultura lançou em 2003 o híbrido de abacaxizeiro BRS Imperial, que tem grande potencial de se estabelecer amplamente nas regiões produtoras, pela sua resistência à fusariose, principal doença da cultura, por possuir folhas sem espinhos e por seus frutos apresentarem excelentes características físico-químicas e boa aparência.bitstream/item/119347/1/comunicado-tecnico-158-Atual.pd

Conditional behavior trees: Definition, executability, and applications

Behavior Trees (BTs) are gaining acceptance in robotics to specify action policies at the deliberative level. Their advantages include modularity, ease of use and increasing tool support. In this paper, we define Conditional Behavior Trees (CBTs) as an extension of BTs wherein actions are decorated considering pre-and post-conditions. CBTs improve on basic BTs in that they enable monitoring the execution of single actions by checking pre-and post-conditions, respectively. Since there might exist action sequences wherein some preconditions are violated, CBT executability may depend on the success/failure of specific actions. We developed an encoding of CBT executability into satisfiability of propositional formulas to be checked off-line in a publicly-available tool that computes the encoding for generic CBTs. For the kind of application scenarios and related behavior specifications that we consider, we show that our approach is effective and yields formal guarantees about the executability of deliberative policies designed as CBTs

A Novel Gaussian Extrapolation Approach for 2D Gel Electrophoresis Saturated Protein Spots

Analysis of images obtained from two-dimensional gel electrophoresis (2D-GE) is a topic of utmost importance in bioinformatics research, since commercial and academic software available currently has proven to be neither completely effective nor fully automatic, often requiring manual revision and refinement of computer generated matches. In this work, we present an effective technique for the detection and the reconstruction of over-saturated protein spots. Firstly, the algorithm reveals overexposed areas, where spots may be truncated, and plateau regions caused by smeared and overlapping spots. Next, it reconstructs the correct distribution of pixel values in these overexposed areas and plateau regions, using a two-dimensional least-squares fitting based on a generalized Gaussian distribution. Pixel correction in saturated and smeared spots allows more accurate quantification, providing more reliable image analysis results. The method is validated for processing highly exposed 2D-GE images, comparing reconstructed spots with the corresponding non-saturated image, demonstrating that the algorithm enables correct spot quantification

A novel Gaussian fitting approach for 2D gel electrophoresis saturated protein spots

Analysis of 2D-GE images is a hot topic in bioinformatics research, since currently available commercial and academic software has proven to be not really effective and not completely automatic, often requiring manual revision of spots detection and refinement of computer generated matches. In this work, we present an effective technique for the detection and the reconstruction of over-saturated protein spots. Firstly, it reveals overexposed areas where spots may be truncated, and plateau regions caused by smeared and overlapped spots. As next, the correct distribution of pixel values in the overexposed areas and plateau regions is recovered by a two-dimensional fitting based on a generalized Gaussian distribution approximating the spots volume. Pixel correction according to the generalized Gaussian curve in saturated and smeared spots allows more accurate quantifications, providing more reliable image analysis results. As validation, we process highly exposed 2D-GE image, containing saturate spots, with respect to the corresponding non-saturated image, confirming that the method can effectively fix the saturated spots and enable correct spots quantification