Dirac sea effects in K+K^+ scattering from nuclei

The ratio $R_T$ of $K^+-^{12}C$ to $K^+-d$ cross sections has been calculated microscopically using a boson-exchange $KN$ amplitude in which the $\sigma$ and $\omega$ mesons are dressed by the modifications of the Dirac sea in nuclear matter. In spite of the fact that this dressing leads to a scaling of the mesons effective mass in nuclear matter, the effect on the $R_T$ ratio is found to be weak.Comment: 8 pages, LaTeX, 2 figures available upon request, LPTB-93-

Improving performance of reflectance diffuse optical imaging using a multicentered mode

We propose a novel multicentered mode for arrangement of optical fibers to improve the imaging performance of reflectance diffuse optical imaging (rDOI). Simulations performed using a semi-infinite model show that the proposed multicentered geometries can achieve a maximum of 42 overlapping measurements. The contrast-to-noise ratio (CNR) analysis indicates that the best spatial resolution is 1 mm in radius and the contrast resolution is less than 1.05 for the multicentered geometries. The results from simulations indicate significant improvement in image quality compared to the single-centered mode and previous geometries. Additional experimental results on a single human subject lead to the conclusion that the proposed multicentered geometries are appropriate for exploring activations in the human brain. From the results of this research, we conclude that the proposed multicentered mode could advance the performance of rDOI both in image quality and practical convenience

Superconformal constraints for QCD conformal anomalies

Anomalous superconformal Ward identities and commutator algebra in N = 1 super-Yang-Mills theory give rise to constraints between the QCD special conformal anomalies of conformal composite operators. We evaluate the superconformal anomalies that appear in the product of renormalized conformal operators and the trace anomaly in the supersymmetric spinor current and check the constraints at one-loop order. In this way we prove the universality of QCD conformal anomalies, which define the non-diagonal part of the anomalous dimension matrix responsible for scaling violations of exclusive QCD amplitudes at the next-to-leading order.Comment: 30 pages, 2 figures, LaTe

Massive Empyema Associated With Transient Hypogammaglobulinemia of Infancy and IgA Deficiency

Transient hypogammaglobulinemia of infancy (THI) is originally defined as a physiological maturation defect of immunoglobulin G (IgG) production that occurs at 3-6 months of age and lasts until 18 to 36 months of age. We report here on a 22-month-old child with THI and IgA deficiency, who had massive pneumococcal empyema. Her depressed IgG level returned to normal within 6 months, but IgA level was still low at 6 yr of age. Although THI is an age-dependent and self-limiting disorder, severe infection that includes an atypical presentation of an infection may occur in some patients and this requires evaluation with immunologic study

Influence of fluid dynamic conditions on 1,3-propanediol production from glycerol by Shimwellia blattae: Carbon flux and cell response

The fluid dynamic conditions play a key role in the development and scaling up of bioprocesses. In aerobic cultures, oxygen is an essential substrate for microbial growth, production and culture maintenance; an effective gas-liquid transfer must be achieved. Changes in fluid dynamics due to stirrer speed can affect negatively to the culture, causing hydrodynamic stress (increasing shear stress) or oxidative stress (by an increase of available oxygen in the liquid phase)

Image informatics strategies for deciphering neuronal network connectivity

Brain function relies on an intricate network of highly dynamic neuronal connections that rewires dramatically under the impulse of various external cues and pathological conditions. Among the neuronal structures that show morphologi- cal plasticity are neurites, synapses, dendritic spines and even nuclei. This structural remodelling is directly connected with functional changes such as intercellular com- munication and the associated calcium-bursting behaviour. In vitro cultured neu- ronal networks are valuable models for studying these morpho-functional changes. Owing to the automation and standardisation of both image acquisition and image analysis, it has become possible to extract statistically relevant readout from such networks. Here, we focus on the current state-of-the-art in image informatics that enables quantitative microscopic interrogation of neuronal networks. We describe the major correlates of neuronal connectivity and present workflows for analysing them. Finally, we provide an outlook on the challenges that remain to be addressed, and discuss how imaging algorithms can be extended beyond in vitro imaging studies

Unexpected Fine-Scale Population Structure in a Broadcast-Spawning Antarctic Marine Mollusc

Several recent empirical studies have challenged the prevailing dogma that broadcast-spawning species exhibit little or no population genetic structure by documenting genetic discontinuities associated with large-scale oceanographic features. However, relatively few studies have explored patterns of genetic differentiation over fine spatial scales. Consequently, we used a hierarchical sampling design to investigate the basis of a weak but significant genetic difference previously reported between Antarctic limpets (Nacella concinna) sampled from Adelaide and Galindez Islands near the base of the Antarctic Peninsula. Three sites within Ryder Bay, Adelaide Island (Rothera Point, Leonie and Anchorage Islands) were each sub-sampled three times, yielding a total of 405 samples that were genotyped at 155 informative Amplified Fragment Length Polymorphisms (AFLPs). Contrary to our initial expectations, limpets from Anchorage Island were found to be subtly, but significantly distinct from those sampled from the other sites. This suggests that local processes may play an important role in generating fine-scale population structure even in species with excellent dispersal capabilities, and highlights the importance of sampling at multiple spatial scales in population genetic surveys