A projective Dirac operator on CP^2 within fuzzy geometry

We propose an ansatz for the commutative canonical spin_c Dirac operator on CP^2 in a global geometric approach using the right invariant (left action-) induced vector fields from SU(3). This ansatz is suitable for noncommutative generalisation within the framework of fuzzy geometry. Along the way we identify the physical spinors and construct the canonical spin_c bundle in this formulation. The chirality operator is also given in two equivalent forms. Finally, using representation theory we obtain the eigenspinors and calculate the full spectrum. We use an argument from the fuzzy complex projective space CP^2_F based on the fuzzy analogue of the unprojected spin_c bundle to show that our commutative projected spin_c bundle has the correct SU(3)-representation content.Comment: reduced to 27 pages, minor corrections, minor improvements, typos correcte

Distributed simulation and industry: Potentials and pitfalls

We present the views of five researchers and practitioners of distributed simulation. Collectively we attempt to address what the implications of distributed simulation are for industry. It is hoped that the views contained herein, and the presentations made by the panelists at the 2002 Winter Simulation Conference will raise awareness and stimulate further discussion on the application of distributed simulation methods and technology in an area that is yet to benefit from the arguable economic benefits that this technique promises

Extracellular Protease Inhibition Alters the Phenotype of Chondrogenically Differentiating Human Mesenchymal Stem Cells (MSCs) in 3D Collagen Microspheres

Matrix remodeling of cells is highly regulated by proteases and their inhibitors. Nevertheless, how would the chondrogenesis of mesenchymal stem cells (MSCs) be affected, when the balance of the matrix remodeling is disturbed by inhibiting matrix proteases, is incompletely known. Using a previously developed collagen microencapsulation platform, we investigated whether exposing chondrogenically differentiating MSCs to intracellular and extracellular protease inhibitors will affect the extracellular matrix remodeling and hence the outcomes of chondrogenesis. Results showed that inhibition of matrix proteases particularly the extracellular ones favors the phenotype of fibrocartilage rather than hyaline cartilage in chondrogenically differentiating hMSCs by upregulating type I collagen protein deposition and type II collagen gene expression without significantly altering the hypertrophic markers at gene level. This study suggests the potential of manipulating extracellular proteases to alter the outcomes of hMSC chondrogenesis, contributing to future development of differentiation protocols for fibrocartilage tissues for intervertebral disc and meniscus tissue engineering.published_or_final_versio

Optimal fibre architecture of soft-matrix ballistic laminates

This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.ijimpeng.2015.10.012Soft-matrix ballistic laminates (such as those composed of fibres of Ultra High Molecular-Weight Polyethylene, e.g. Dyneema® HB26 and Spectra Shield), find extensive use as catching type armour systems. The relationship between the lay-up of these laminates with respect to the observed failure mechanisms has not been empirically investigated in the open literature, and is the subject of this work. Lay-ups are characterised by two parameters: (i) sequencing (or interply lay-up angle) θ̅ and (ii) in-plane anisotropy β, and can be mapped on to θ̅–β space. Four geometries that lie at the extrema of this parameter space are designed, built and tested. Testing is through ball bearing impact on circular clamped plates. The anisotropy (β) is coupled to the macroscopic response of the plates, whilst sequencing (θ̅) is coupled to the microscopic response. Penetration velocity is strongly affected by pull-out at the boundary, and in the present study this is shown to account for two-thirds of the ballistic resistance. The results have implications for validation testing on scaled samples, predictive modelling and simulation, and armour design.The authors wish to thank DSM Dyneema for supplying material for the construction of laminate plates. Dyneema® is a trademark of DSM. Dr B. P. Russell was supported by a Ministry of Defence / Royal Academy of Engineering Research Fellowship. The authors are also appreciative of technical insight provided by Dr. O’Masta

Effect of Difference Tropical Fibrous Feeds on Feed Intake and Digestibility in Swamps Buffaloes Compared to Ongole Cattle

This research was aimed to examine the effect of difference fibrous feeds on feed intake and digestibility in swamps buffaloes compared to ongoles cattles. Twelve ongole and twelve buffaloes were used in in vivo digestibility. Ten feeds were used in this experiment, namely Peanut Haulm (PH), King Grass (KG), Corn stover (CS), Elephan Grass (EG), Rice Straw (RS), Soja Straw (SS), Corn Straw (CST), Glyricidea (Gli), and Caliandra (Cal). The observed variabels were intake of DM, OM, CP, NDF. The results showed that DM and OM intakes were significantly influenced by feed stuffs origin ranged from the lowest (Gli) of 29.55 g DMI/kg0.75 to the highest (CS) of 94.88 g/kg0.75. OM intake of buffaloes was higher than that of ongole cattle supported by organic matter (OM) digestibility data (61.51 vs 59.51). The digestibility of nutrient was significantly influenced by feed stuffs origin. OM digestibility of SS were lowest while the highest were CST of 54.56 and 71.66% respectively. Digestibility of CP was also significantly influenced by feed stuffs origin. The lowest Digestible Crude Protein was CST and the highest was PH of 44.10 and 67.99% respectively. The digestibility of NDF and ADF were significantly influenced by feed stuffs. The lowest NDF and ADF digestibilities were Cal of 40.84 and 33.19% and the highest digestibility of NDF and ADF were CST of 68.53 and 63.57%. It can be concluded that there were an important variation of feed compositions and digestibility of fibrous feeds. Buffalo were better than cattle on capacity of ingestion and utilization of fibrous feed. (Animal Production 12(2): 86-90 (2010

Matrix models on the fuzzy sphere

Field theory on a fuzzy noncommutative sphere can be considered as a particular matrix approximation of field theory on the standard commutative sphere. We investigate from this point of view the scalar $\phi^4$ theory. We demonstrate that the UV/IR mixing problems of this theory are localized to the tadpole diagrams and can be removed by an appropiate (fuzzy) normal ordering of the $\phi^4$ vertex. The perturbative expansion of this theory reduces in the commutative limit to that on the commutative sphere.Comment: 6 pages, LaTeX2e, Talk given at the NATO Advanced Research Workshop on Confiment, Topology, and other Non-Perturbative Aspects of QCD, Stara Lesna, Slovakia, Jan. 21-27, 200

Risk factors for discordant immune response among HIV-infected patients initiating antiretroviral therapy: A retrospective cohort study

Background. The therapeutic goal of antiretroviral therapy (ART) is sustained immune recovery and viral suppression. However, some patients experience poor CD4 cell count responses despite achieving viral  suppression. Such discordant immune responses have been associated with poor clinical outcomes.Objective. We aimed to determine the prevalence of discordant immune response and explore associated factors in a retrospective cohort of patients attending 2 large public sector clinics, during the 6 months following ART initiation.Methods. Data were analysed from 810 HIV-infected adults initiated on first-line HAART at 2 clinics in Johannesburg, between 1 November 2008 and 31 December 2009. Multivariate logistic regression models were used to estimate adjusted odds ratios (AORs) to determine associations between discordant immune response and clinical and demographic factors.Results. At ART initiation, 65% (n=592) of participants were female, with a mean age of 38.5 years. Median baseline CD4 cell count was 155 cells/mm3, 70% (n=645) of patients had a haemoglobin level >11 g/dl and 88% (n=803) were initiated on stavudine-lamivudine-efavirenz/nevirapine (D4T-3TC-EFV/NVP). Six months after ART initiation, 24% (n=220) of patients had a discordant immune response and 7% (n=67) a discordant virological response. On multivariate analysis, baseline CD cell count .200 cells/mm3 (AOR 3.02; 95% confidence interval (CI) 2.08 - 4.38; p<0.001) and moderate anaemia (8.0 - 9.4 g/dl) atbaseline (AOR 2.30; 95% CI 1.25 - 4.59; p=0.007) were independently associated with the development of discordant immune response, after adjustment for education level, World Health Organization (WHO) clinical stage and ART regimen.Conclusions. Discordant immune response following ART initiation was common and associated with baseline anaemia and CD4 cell count in our cohort. Intensive monitoring of at-risk individuals may improve clinical outcomes

Extended phase space thermodynamics for charged and rotating black holes and Born-Infeld vacuum polarization

We investigate the critical behaviour of charged and rotating AdS black holes in d spacetime dimensions, including effects from non-linear electrodynamics via the Born-Infeld action, in an extended phase space in which the cosmological constant is interpreted as thermodynamic pressure. For Reissner-Nordstrom black holes we find that the analogy with the Van der Walls liquid-gas system holds in any dimension greater than three, and that the critical exponents coincide with those of the Van der Waals system. We find that neutral slowly rotating black holes in four space-time dimensions also have the same qualitative behaviour. However charged and rotating black holes in three spacetime dimensions do not exhibit critical phenomena. For Born-Infeld black holes we define a new thermodynamic quantity B conjugate to the Born-Infeld parameter b that we call Born-Infeld vacuum polarization. We demonstrate that this quantity is required for consistency of both the first law of thermodynamics and the corresponding Smarr relation.Comment: 23 pages, 32 figures, v2: minor changes, upgraded reference