31,715 research outputs found
Metastable Vacua in Superconformal SQCD-like Theories
We study dynamical supersymmetry breaking in vector-like superconformal N=1
gauge theories. We find appropriate deformations of the superpotential to
overcome the problem of the instability of the non supersymmetric vacuum. The
request for long lifetime translates into constraints on the physical couplings
which in this regime can be controlled through efficient RG analysis.Comment: 17 pages, 7 figures, JHEP3.cl
Some recent developments in the theory of Lie group symmetries for PDEs
Lie group symmetry methods provide a powerful tool for the analysis of PDEs. Over the last thirty years, considerable progress has been made in the development of this field. In this article, we provide a brief introduction to the method developed by Lie for the systematic computation of symmetries, then move on to a survey of some of the more recent developments. Our focus is on the use of Lie symmetry methods to construct fundamental solutions of partial differential equations of parabolic type. We will show how recent work has uncovered an intriguing connection between Lie symmetry analysis and the theory of integral transforms. Fundamental solutions of families of PDEs which arise in various applications, can be obtained by exploiting this connection. The major applications we give will be in financial mathematics. We will illustrate our results with the problem of pricing a so called zero coupon bond, as well as giving some applications to option pricing. We also discuss some results on group invariant solutions and show how an important PDE in nilpotent harmonic analysis can be studied via its group invariant solutions
Surveillance evaluation of the national cancer registry in Sabah, Malaysia
BACKGROUND:
Cancer is the fourth leading cause of death in Sabah Malaysia with a reported agestandardized incidence rate was 104.9 per 100,000 in 2007. The incidence rate depends on nonmandatory notification in the registry. Underreporting will provide the false picture of cancer control program effectiveness. The present study was to evaluate the performance of the cancer registry system in terms of representativeness, data quality, simplicity, acceptability and timeliness and provision of recommendations for improvement.
MATERIALS AND METHODS:
The evaluation was conducted among key informants in the National Cancer Registry (NCR) and reporting facilities from FebMay 2012 and was based on US CDC guidelines. Representativeness was assessed by matching cancer case in the Health Information System (HIS) and state pathology records with those in NCR. Data quality was measured through case finding and reabstracting of medical records by independent auditors. The reabstracting portion comprised 15 data items. Selfadministered questionnaires were used to assess simplicity and acceptability. Timeliness was measured from date of diagnosis to date of notification received and data dissemination.
RESULTS:
Of 4613 cancer cases reported in HIS, 83.3% were matched with cancer registry. In the state pathology centre, 99.8% was notified to registry. Duplication of notification was 3%. Data completeness calculated for 104 samples was 63.4%. Registrars perceived simplicity in coding diagnosis as moderate. Notification process was moderately acceptable. Median duration of interval 1 was 5.7 months.
CONCLUSIONS:
The performances of registry's attributes are fairly positive in terms of simplicity, case reporting sensitivity, and predictive value positive. It is moderately acceptable, data completeness and inflexible. The usefulness of registry is the area of concern to achieve registry objectives. Timeliness of reporting is within international standard, whereas timeliness to data dissemination was longer up to 4 years. Integration between existing HIS and national registration department will improve data quality
A synthetic player for Ayὸ board game using alpha-beta search and learning vector quantization
Game playing especially, Ayὸ game has been an important topic of research in artificial intelligence and several machine learning approaches have been used, but the need to optimize computing resources is important to encourage the significant interest of users. This study presents a synthetic player (Ayὸ) implemented using Alpha-beta search and Learning Vector Quantization network. The program for the board game was written in Java and MATLAB. Evaluation of the synthetic player was carried out in terms of the win percentage and game length. The synthetic player had a better efficiency compared to the traditional Alpha-beta search algorithm
Assessing the efficacy of dyes extracted from some local plants for colouring cotton fabrics
Natural dyes from plant, animal and mineral sources have been used for centuries across the world. This study however, describes art studio quasi experiments conducted with the leaves, barks, seeds, roots, and fruit pods of 21 local plants to ascertain their potential for yielding dyes that would colour cotton fabrics and withstand frequent laundering. The methodology involved boiling the crushed leaf samples or chopped woody samples for between 15 and 30 minutes, draining the liquor into a plastic bowl, immersing the test cotton fabric and dyeing it hot or cold. With the exception of Adansonia digitata dye which was too weak to stain the fabric and Bixa orellana dye which was not colourfast and faded beyond recognition within six weeks, the other 19 plants yielded highly coloured, light- and wash-fast dyes of varying strengths, suggesting their feasibility for teaching basic skills in tie-dyeing, batik, watercolour painting and printmaking, which constitute integral aspects of the Visual Arts curriculum in Ghana. The study identified sodium carbonate as an effective mordant for improving the colour, strength and fastness of the brown Bridelia ferruginea dye which is the backbone of the indigenous textiles industry.Keywords: Natural dye, local plants, colour work, visual arts curriculum, Ghan
Non-Markovian reduced dynamics and entanglement evolution of two coupled spins in a quantum spin environment
The exact quantum dynamics of the reduced density matrix of two coupled spin
qubits in a quantum Heisenberg XY spin star environment in the thermodynamic
limit at arbitrarily finite temperatures is obtained using a novel operator
technique. In this approach, the transformed Hamiltonian becomes effectively
Jaynes-Cumming like and thus the analysis is also relevant to cavity quantum
electrodynamics. This special operator technique is mathematically simple and
physically clear, and allows us to treat systems and environments that could
all be strongly coupled mutually and internally. To study their entanglement
evolution, the concurrence of the reduced density matrix of the two coupled
central spins is also obtained exactly. It is shown that the dynamics of the
entanglement depends on the initial state of the system and the coupling
strength between the two coupled central spins, the thermal temperature of the
spin environment and the interaction between the constituents of the spin
environment. We also investigate the effect of detuning which in our model can
be controlled by the strength of a locally applied external magnetic field. It
is found that the detuning has a significant effect on the entanglement
generation between the two spin qubits.Comment: 9 pages (two-coulumn), 6 figures. To appear in Phys. Rev.
Supersymmetry Breaking in Chern-Simons-matter Theories
Some of supersymmetric Chern-Simons theories are known to exhibit
supersymmetry breaking when the Chern-Simons level is less than a certain
number. The mechanism of the supersymmetry breaking is, however, not clear from
the field theory viewpoint. In this paper, we discuss vacuum states of pure Chern-Simons theory and Chern-Simons-matter theories of
quiver type using related theories in which Chern-Simons terms are replaced
with (anti-)fundamental chiral multiplets. In the latter theories,
supersymmetry breaking can be shown to occur by examining that the vacuum
energy is non-zero.Comment: 17 pages, 3 figures, v2) references adde
A study of dry matter partitioning and concentration in grain Amaranth (Amaranthus cruentus)
No Abstract
Bacteriocinogenicity and production of pyocins from Pseudomonas species isolated in Lagos, Nigeria
A total of 52 strains of Pseudomonas identified as P. aeruginosa (27), P. putida (9), P. fluorescens (13) and P. stutzeri (3) were isolated from Nigerian patients with burns, wound and skin infections, UTI,diarrhoea and eye infections. 81.5, 55.6, 76.9 and 33.3% of these species produced pyocins at a range of 410 – 670 g/ml. High yields of pyocins at 35 – 37oC, which declined sharply at temperatures above37oC were obtained from all the producing strains. The strains also displayed significant pyocin expression (P 3 mm. These pyocins also displayed growth inhibitory activity against some Nigerian isolates of Gram-positive and Gram-negative bacteria when undiluted and at 1:2 - 1:16 dilutions. The susceptible organisms include Bacillus cereus, Listeria monocytogenes, Klebsiella spp., Staphylococcus aureus, S. epidermidis,Proteus spp. and Vibrio parahaemolyticus. The results of this study have provided evidence for broadspectrum antibacterial activity of pyocins elicited by Pseudomonas species from Nigeri
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