Superconformal Primary Fields on a Graded Riemann Sphere

Primary superfields for a two dimensional Euclidean superconformal field theory are constructed as sections of a sheaf over a graded Riemann sphere. The construction is then applied to the N=3 Neveu-Schwarz case. Various quantities in the N=3 theory are calculated and discussed, such as formal elements of the super-Mobius group, and the two-point function.Comment: LaTeX2e, 23 pages; fixed typos, sorted references, modified definition of primary superfield on page

Antibacterial activity of marine source extracts against multidrug resistant organisms

Antimicrobial resistance is the major problem of global dimensions with a significant impact on morbidity,mortality and healthcare-associated costs. The problem has recently been worsened by the steady increase in multiresistant strains and by the restriction of antibiotic discovery and development programs. Methicillin-resistant Staphylococcus aureus, pseudomonads and Escherichia coli are a major nosocomial and community-acquired pathogens for which few existing antibiotics are efficacious. The current study was conducted to investigate antibacterial activity of natural seaweed sources. Approach: Gracilaria changii Euchema denticulatum and sea cucumbers extracts against Methicillin-resistan-Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes, Vibrio cholerae, Pseudomonas aeruginosa and Klebsiella pneumoniae. Results: The Minimal Inhibitory Concentration (MIC) values and Minimal Bactericidal Concentration(MBC) values of methanol extract were used against all assayed bacteria. Results indicated that G. changii, E. denticulatum and sea cucumbers extracts must possess major anti bacterial components against infectious microorganisms. Conclusion: The results obtained indicate that Gracilaria changii and Euchema denticulatum could be a source of natural products with antibiotic modifying activity to be used against multidrug resistant bacteria

Removing noise from pyrosequenced amplicons

Background In many environmental genomics applications a homologous region of DNA from a diverse sample is first amplified by PCR and then sequenced. The next generation sequencing technology, 454 pyrosequencing, has allowed much larger read numbers from PCR amplicons than ever before. This has revolutionised the study of microbial diversity as it is now possible to sequence a substantial fraction of the 16S rRNA genes in a community. However, there is a growing realisation that because of the large read numbers and the lack of consensus sequences it is vital to distinguish noise from true sequence diversity in this data. Otherwise this leads to inflated estimates of the number of types or operational taxonomic units (OTUs) present. Three sources of error are important: sequencing error, PCR single base substitutions and PCR chimeras. We present AmpliconNoise, a development of the PyroNoise algorithm that is capable of separately removing 454 sequencing errors and PCR single base errors. We also introduce a novel chimera removal program, Perseus, that exploits the sequence abundances associated with pyrosequencing data. We use data sets where samples of known diversity have been amplified and sequenced to quantify the effect of each of the sources of error on OTU inflation and to validate these algorithms

Observation of Ground-State Two-Neutron Decay

Neutron decay spectroscopy has become a successful tool to explore nuclear properties of nuclei with the largest neutron-to-proton ratios. Resonances in nuclei located beyond the neutron dripline are accessible by kinematic reconstruction of the decay products. The development of two-neutron detection capabilities of the Modular Neutron Array (MoNA) at NSCL has opened up the possibility to search for unbound nuclei which decay by the emission of two neutrons. Specifically this exotic decay mode was observed in 16Be and 26O.Comment: To be published in Acta Physica Polonica

Exploring the Low-ZZ Shore of the Island of Inversion at N=19N = 19

The technique of invariant mass spectroscopy has been used to measure, for the first time, the ground state energy of neutron-unbound $^{28}\textrm{F},$ determined to be a resonance in the $^{27}\textrm{F} + n$ continuum at $2\underline{2}0 (\underline{5}0)$ keV. States in $^{28}\textrm{F}$ were populated by the reactions of a 62 MeV/u $^{29}\textrm{Ne}$ beam impinging on a 288 $\textrm{mg/cm}^2$ beryllium target. The measured $^{28}\textrm{F}$ ground state energy is in good agreement with USDA/USDB shell model predictions, indicating that $pf$ shell intruder configurations play only a small role in the ground state structure of $^{28}\textrm{F}$ and establishing a low-$Z$ boundary of the island of inversion for N=19 isotones.Comment: 5 pages, 4 figures, to be published in Phys. Rev. Let

Role of anisotropic impurity scattering in anisotropic superconductors

A theory of nonmagnetic impurities in an anisotropic superconductor including the effect of anisotropic (momentum-dependent) impurity scattering is given. It is shown that for a strongly anisotropic scattering the reduction of the pair-breaking effect of the impurities is large. For a significant overlap between the anisotropy functions of the scattering potential and that of the pair potential and for a large amount of anisotropic scattering rate in impurity potential the superconductivity becomes robust vis a vis impurity concentration. The implications of our result for YBCO high-temperature superconductor are discussed.Comment: 14 pages, RevTeX, 5 PostScript figures, to be published in Phys. Rev. B (December 1, 1996

Natural product activity against Methicillin-Resistant Staphylococcus aureus genes

Methicilin Resistant Staphylococcus aureus (MRSA) implicated in many post-surgical and cancer treatment as well hospital and community fatalities need to be treated with an effective alternative antimicrobial agent. In the search for anti-MRSA agent, 2 types of natural products were investigated for inhibitory activity against MRSA. In addition to the bioassay, the activity of the anti-MRSA agent was elucidated based on the effect of both natural products on nucleotide changes of chromosome-encoded genes. In this study, the methanol extract of the red marine algae and the natural pure honey were studied for its antibacterial property based on disc diffusion test and Minimum Inhibitory Concentration (MIC). The effects of both natural products on selected gene sequences of S. aureus’s were determined by RT-PCR analysis. The genes of interest, which have been chosen in this study, are genes that are involved in the antibacterial mechanism including inhibition of cell wall synthesis, protein synthesis and nucleic acid synthesis. Five genes of interest chosen in this study include mecA gene, mecR1 gene, mecI gene, adaB gene and sav1017 gene. The results for antibacterial property showed the methanol extract of a red seaweed and the pure honey, inhibited growth of S. aureus strain according to the inhibition zones around discs saturated with the seaweed extract and pure honey, respectively. The MIC test showed decrease in growth of MRSA isolates after growing in broth incorporated with the extract and honey, respectively. The effect of the inhibitory activity of the natural products on selected gene sequences showed that several nucleotide changes occurred in the sequences of certain genes of interest based on the gene sequences of the cDNA after RT-PCR was carried out on the mRNA of S. aureus treated with the natural products. This research underlined that the inhibition effect of the natural products may be chromosome mediated evidenced by the changes of chromosome-encoded genes. The significant findings on activities of the seaweed extract and pure honey may become very useful in the process to find a better treatment for S. aureus infection especially, for the multiple drug resistant isolates. In addition, it is also, a new finding for natural product discovery through gene-expression analysis

Application of RT-PCR to detect treated and untreated Staphylococcus aureus genes with marine algae

Methacillin Resistant Staphylococcus aureus (MRSA), Extended Spectrum Beta Lactamase (ESBL) organisms and Multiple Drug Resistant Organism (MDRO). Therefore, this study was designed to explore an alternative antibacterial product derived from seaweed extracts, Gracilaria changii and Euchema denticulatum, through the study of DNA and RNA encoding genes of interest in MRSA and non-MRSA. The target of this study is to amplification of several untreated and treated S. aureus and E. coli genes that are potentially involved in the antibacterial activities through RT-PCR assay. G. changii and E. denticulatum extracts showed inhibitory activity against S. aureus, several genes in this pathogen were chosen to study the effect of both seaweed extracts on the genes through PCR and RT-PCR analysis. However, the predicted inhibitory mechanism of both seaweeds extracts on mecA gene was not fully elucidated in the study. The investigation could scientifically proof the natural products to be potentially potent antibacterial agents

Psychophysical Investigations into the Role of Low-Threshold C Fibres in Non-Painful Affective Processing and Pain Modulation

We recently showed that C low-threshold mechanoreceptors (CLTMRs) contribute to touch-evoked pain (allodynia) during experimental muscle pain. Conversely, in absence of ongoing pain, the activation of CLTMRs has been shown to correlate with a diffuse sensation of pleasant touch. In this study, we evaluated (1) the primary afferent fibre types contributing to positive (pleasant) and negative (unpleasant) affective touch and (2) the effects of tactile stimuli on tonic muscle pain by varying affective attributes and frequency parameters. Psychophysical observations were made in 10 healthy participants. Two types of test stimuli were applied: stroking stimulus using velvet or sandpaper at speeds of 0.1, 1.0 and 10.0 cm/s; focal vibrotactile stimulus at low (20 Hz) or high (200 Hz) frequency. These stimuli were applied in the normal condition (i.e. no experimental pain) and following the induction of muscle pain by infusing hypertonic saline (5%) into the tibialis anterior muscle. These observations were repeated following the conduction block of myelinated fibres by compression of sciatic nerve. In absence of muscle pain, all participants reliably linked velvet-stroking to pleasantness and sandpaper-stroking to unpleasantness (no pain). Likewise, low-frequency vibration was linked to pleasantness and high-frequency vibration to unpleasantness. During muscle pain, the application of previously pleasant stimuli resulted in overall pain relief, whereas the application of previously unpleasant stimuli resulted in overall pain intensification. These effects were significant, reproducible and persisted following the blockade of myelinated fibres. Taken together, these findings suggest the role of low-threshold C fibres in affective and pain processing. Furthermore, these observations suggest that temporal coding need not be limited to discriminative aspects of tactile processing, but may contribute to affective attributes, which in turn predispose individual responses towards excitatory or inhibitory modulation of pain

Note on SLE and logarithmic CFT

It is discussed how stochastic evolutions may be linked to logarithmic conformal field theory. This introduces an extension of the stochastic Loewner evolutions. Based on the existence of a logarithmic null vector in an indecomposable highest-weight module of the Virasoro algebra, the representation theory of the logarithmic conformal field theory is related to entities conserved in mean under the stochastic process.Comment: 10 pages, LaTeX, v2: version to be publishe