Scattering in three-dimensional fuzzy space

We develop scattering theory in a non-commutative space defined by a $su(2)$ coordinate algebra. By introducing a positive operator valued measure as a replacement for strong position measurements, we are able to derive explicit expressions for the probability current, differential and total cross-sections. We show that at low incident energies the kinematics of these expressions is identical to that of commutative scattering theory. The consequences of spacial non-commutativity are found to be more pronounced at the dynamical level where, even at low incident energies, the phase shifts of the partial waves can deviate strongly from commutative results. This is demonstrated for scattering from a spherical well. The impact of non-commutativity on the well's spectrum and on the properties of its bound and scattering states are considered in detail. It is found that for sufficiently large well-depths the potential effectively becomes repulsive and that the cross-section tends towards that of hard sphere scattering. This can occur even at low incident energies when the particle's wave-length inside the well becomes comparable to the non-commutative length-scale.Comment: 12 pages, 6 figure

Spectrum of the three dimensional fuzzy well

We develop the formalism of quantum mechanics on three dimensional fuzzy space and solve the Schr\"odinger equation for a free particle, finite and infinite fuzzy wells. We show that all results reduce to the appropriate commutative limits. A high energy cut-off is found for the free particle spectrum, which also results in the modification of the high energy dispersion relation. An ultra-violet/infra-red duality is manifest in the free particle spectrum. The finite well also has an upper bound on the possible energy eigenvalues. The phase shifts due to scattering around the finite fuzzy potential well have been calculated

Relativistic mean field formulation of clustering in heavy nuclei

Very little is known about clustering in heavy nuclei and in particular the interaction between the correlated cluster nucleons and remaining core nucleons. Currently the phenomenological Saxon-Woods plus cubic Saxon-Woods core-cluster potential successfully predicts the alpha decay half-life and energy band spectra of a number of heavy nuclei. This model, however, lacks a microscopic understanding of clustering phenomenon in these heavy nuclear systems. A fully relativistic microscopic formalism is presented, which generates the core-cluster potential by means of the McNeil, Ray and Wallace based double folding procedure. The core and cluster baryon densities are calculated by using a relativistic mean field approach. The Lorentz covariant IA1 representation of the nucleon-nucleon interaction is folded with the core and cluster densities. Theoretical predictions of the ground-state decay half-life and positive parity energy band of 212Po are obtained with the relativistic mean field formalism and which are compared to the results from the phenomenological Saxon-Woods plus cubic Saxon-Wood core-cluster potential and microscopic M3Y interaction

Micromanipulation at an infertility centre

Aim. Human in vitro fertilisation (IVF) and gamete intrafallopian transfer have been used in the management of various forms of infertility. In cases of severe male-factor infertility, fertilisation can be a factor. In this study micromanipulation was used to increase fertilisation in such cases.Methods. Two micromanipulation techniques, subzonal sperm injection (SUZI) and partial zona dissection (PZD), were used to assist fertilisation in patients with abnorTl)al semen parameters. Ten couples with severe oligo-, teratoand asthenozoospermia participated in the SUZI programme. Seventy-three oocytes were obtained from these 10 patients. PZD was used on day 1 oocytes in cases of male infertility as well as a rescue attempt on day 2 oocytes when fertilisation had failed after routine insemination.Results. The SUZI technique had a fertilisation rate of 37,7%. In this group, a biochemical pregnancy was achieved. Differences between the fertilisation rate of conventionallVF (33,3%) and PZD (56,3%) in cases of male infertility, were not statistically significant although a clinical difference could be detected. PZD was statistically effective in facilitating fertilisation (37,5% v. 8,3%) in couples where this procedure was introduced to reinseminate 24-hour-old unfertilised oocytes. Four patients received PZD reinseminated embryos. An average of 1,45 PZD embryos were replaced and 1 implantation pregnancy was confirmed.Conclusion. The micromanipulation results are encouraging arid seemed to increase the efficiency of IVF in humans. Furthermore, our data support the conclusion that micromanipulation procedures can bring about pregnancies

Phyllosticta citricarpa and sister species of global importance to Citrus.

Several Phyllosticta species are known as pathogens of Citrus spp., and are responsible for various disease symptoms including leaf and fruit spots. One of the most important species is P. citricarpa, which causes a foliar and fruit disease called citrus black spot. The Phyllosticta species occurring on citrus can most effectively be distinguished from P. citricarpa by means of multilocus DNA sequence data. Recent studies also demonstrated P. citricarpa to be heterothallic, and reported successful mating in the laboratory. Since the domestication of citrus, different clones of P. citricarpa have escaped Asia to other continents via trade routes, with obvious disease management consequences. This pathogen profile represents a comprehensive literature review of this pathogen and allied taxa associated with citrus, focusing on identification, distribution, genomics, epidemiology and disease management. This review also considers the knowledge emerging from seven genomes of Phyllosticta spp., demonstrating unknown aspects of these species, including their mating behaviour.TaxonomyPhyllosticta citricarpa (McAlpine) Aa, 1973. Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes, Order Botryosphaeriales, Family Phyllostictaceae, Genus Phyllosticta, Species citricarpa.Host rangeConfirmed on more than 12 Citrus species, Phyllosticta citricarpa has only been found on plant species in the Rutaceae.Disease symptomsP. citricarpa causes diverse symptoms such as hard spot, virulent spot, false melanose and freckle spot on fruit, and necrotic lesions on leaves and twigs.Useful websitesDOE Joint Genome Institute MycoCosm portals for the Phyllosticta capitalensis (https://genome.jgi.doe.gov/Phycap1), P. citriasiana (https://genome.jgi.doe.gov/Phycit1), P. citribraziliensis (https://genome.jgi.doe.gov/Phcit1), P. citrichinaensis (https://genome.jgi.doe.gov/Phcitr1), P. citricarpa (https://genome.jgi.doe.gov/Phycitr1, https://genome.jgi.doe.gov/Phycpc1), P. paracitricarpa (https://genome.jgi.doe.gov/Phy27169) genomes. All available Phyllosticta genomes on MycoCosm can be viewed at https://genome.jgi.doe.gov/Phyllosticta

Finding needles in haystacks: linking scientific names, reference specimens and molecular data for Fungi

DNA phylogenetic comparisons have shown that morphology-based species recognition often underestimates fungal diversity. Therefore, the need for accurate DNA sequence data, tied to both correct taxonomic names and clearly annotated specimen data, has never been greater. Furthermore, the growing number of molecular ecology and microbiome projects using high-throughput sequencing require fast and effective methods for en masse species assignments. In this article, we focus on selecting and re-annotating a set of marker reference sequences that represent each currently accepted order of Fungi. The particular focus is on sequences from the internal transcribed spacer region in the nuclear ribosomal cistron, derived from type specimens and/or ex-type cultures. Re-annotated and verified sequences were deposited in a curated public database at the National Center for Biotechnology Information (NCBI), namely the RefSeq Targeted Loci (RTL) database, and will be visible during routine sequence similarity searches with NR_prefixed accession numbers. A set of standards and protocols is proposed to improve the data quality of new sequences, and we suggest how type and other reference sequences can be used to improve identification of Fungi