External job satisfaction factors improving the overall job satisfaction of selected five-star hotel employees

Published ArticleOne of the 2011 South African National Tourism Sector Strategy objectives is to "provide excellent people development and decent work within the tourism sector". The hospitality industry is, however, not regarded as a provider of decent work and a close link exists between decent work and job satisfaction. External job satisfaction can be defined as satisfaction relating to the work environment of employees. The purpose of this study was to identify the external job satisfaction factors which contribute to overall job satisfaction of employees in selected five-star hotels. The instrument used to gather the quantitative data was a newly developed index based on the literature review conducted. The empirical study was conducted among 124 employees of four five-star hotels in the Western Cape. All three factors identified (supervision, work environment and work itself) were found to be significantly and positively correlated with overall job satisfaction in five-star hotels in the Western Cape

The abundance of moduli, modulini and gravitinos produced by the vacuum fluctuation

Moduli, modulini and the gravitino have gravitational-strength interactions, and thermal collisions after reheating create all of them with roughly the same abundance. With their mass of order 100\GeV, corresponding to gravity-mediated supersymmetry breaking, this leads to the well-known bound \gamma T\sub R\lsim 10^9\GeV on the reheat temperature, where $\gamma\leq 1$ is the entropy dilution factor. The vacuum fluctuation also creates these particles, with abundance determined by the solution of the equation for the mode function. Taking the equation in each case to be the one corresponding to a free field, we consider carefully the behaviour of the effective mass during the crucial era after inflation. It may have a rapid oscillation, which does not however affect the particle abundance. Existing estimates are confirmed; the abundance of modulini and (probably) of moduli created from the vacuum is less than from thermal collisions, but the abundance of gravitinos may be much bigger, leading to a tighter bound on $T\sub R$ if supersymmetry breaking is gravity-mediated. It is noted that in the case of gauge-mediated supersymmetry breaking, the abundance of the gravitino may be sufficient to make it a dark matter candidate.Comment: 14 pages. v3 as it will appear in PL

MEASUREMENTS AND MODELS OF COLLOIDAL PARTICLE DYNAMICS AND ENERGY LANDSCAPES IN MAGNETIC FIELDS AND WITH ADDITIVES IN SOLUTION

Understanding colloidal interactions upon the application of external fields or the addition of secondary components has huge implications for engineering new particle-based materials and products. Electric or magnetic fields can control many particle collective dynamics and structures, leading to novel ordered materials, and can be used for studying nonequilibrium state behavior and for creating innovative active particle systems. Similarly, modulating particle-surface interactions in the presence of additives could enable the design of particles that favorably deposit onto a desired substrate for personal care products and drug delivery. In this dissertation, two different colloidal systems are studied and the dynamics and energies of both are fully characterized. For the first system, the fundamental phenomena influencing magnetic particle behavior in a rotating magnetic field were identified by matching simulations with video microscopy experimental data. In the second system, the mechanisms of core-shell microcapsule binding were characterized as a function of surfactant and polymer concentrations. Magnetic particle interactions and assembly in rotating magnetic fields were systematically quantified by first measuring single particle and doublet rotation and particle-particle separation across a frequency range for two different field amplitudes. Then, multiple particle assembly from a chain to a condensed structure was measured as a function of field amplitude and frequency. Stochastic models were also developed in parallel to match the one, two and multiple particle experimental observations and to unequivocally show how specific variables and physics in the model influence key features in the real system. The simulations were then used to further characterize the kinetics and thermodynamics by solving the one-dimensional Fokker-Planck (FP) equation for effective pair potentials for the two-particle system and an order-parameter FP equation to characterize the assembly process for multiple particle systems. The resulting diffusivity and effective energy landscapes illustrate how particle interactions, assembly pathways, and microstructures can be tuned by applied field conditions. Total Internal Reflection Microscopy (TIRM) was conducted on two different anionic microcapsules, as provided by an industry collaborator, to study how fragrance particle deposition onto human hair can be engineered under shampooing conditions. Experimental videos of the capsules interacting with a glass slide, which is negatively charged to mimic human hair, were analyzed as a function of increasing either amphiphilic surfactant or cationic polymer weight percent. Image analysis algorithms enabled us to capture particle trajectories in x, y and z, from which deposition lifetimes and potential energy profiles were calculated. The results revealed the various interactions that influence capsule deposition and will inform future work on how the capsules deposit in solutions with both surfactants and polymers

Cosmology with a TeV mass GUT Higgs

The most natural way to break the GUT gauge symmetry is with a Higgs field whose vacuum expectation value is of order 10^{16}\,\mbox{GeV} but whose mass is of order $10^2$ to 10^3\,\mbox{GeV}. This can lead to a cosmological history radically different from what is usually assumed to have occurred between the standard inflationary and nucleosynthesis epochs, which may solve the gravitino and Polonyi/moduli problems in a natural way.Comment: 4 pages, revte

A Model of Direct Gauge Mediation

We present a simple model of gauge mediation (GM) which does not have a messenger sector or gauge singlet fields. The standard model gauge groups couple directly to the sector which breaks supersymmetry dynamically. This is the first phenomenologically viable example of this type in the literature. Despite the direct coupling, the model can preserve perturbative gauge unification. This is achieved by the inverted hierarchy mechanism which generates a large scalar expectation value compared to the size of supersymmetry breaking. There is no dangerous negative contribution to the squark, slepton masses due to two-loop renormalization group equation. The potentially non-universal supergravity contribution to the scalar masses can be suppressed enough to maintain the virtue of the gauge mediation. The model is completely chiral, and one does not need to forbid mass terms for the messenger fields by hand. Beyond the simplicity of the model, it possesses cosmologically desirable features compared to the original models of GM: an improved gravitino and string moduli cosmology. The Polonyi problem is back unlike in the original GM models, but is still much less serious than in hidden sector models.Comment: LaTeX, 12 page

Pro-inflammatory flagellin proteins of prevalent motile commensal bacteria are variably abundant in the intestinal microbiome of elderly humans

Peer reviewedPublisher PD

Experimental Composite Guidance Conduits for Peripheral Nerve Repair: An Evaluation of Ion Release

Poly (lactide-co-glycolide) (PLGA) - Pluronic F127 - glass composites have demonstrated excellent potential, from the perspective of controlled mechanical properties and cytocompatibility, for peripheral nerve regeneration. In addition to controlling the mechanical properties and cytotoxicity for such composite devices, the glass component may mediate specific responses upon implantation via degradation in the physiological environment and release of constituent elements. However, research focused on quantifying the release levels of such therapeutic ions from these experimental medical devices has been limited. To redress the balance, this paper explores the ion release profiles for Si4+, Ca2+, Na+, Zn 2+, and Ce4+ from experimental composite nerve guidance conduits (CNGC) comprising PLGA (at 12.5, and 20 wt.%), F127 (at 0, 2.5 and 5 wt.%) and various loadings of Si-Ca-Na-Zn-Ce glass (at 20 and 40 wt.%) for incubation periods of up to 28 days. The concentration of each ion, at various time points, was determined using Inductively Coupled Plasma-Atomic Emission Spectrometry (Perkin Elmer Optima 3000). It was observed that the Si4+, Na+, Ca2+, Zn2+ release from CNGCs in this study ranged from 0.22 to 6.477 ppm, 2.307 to 3.277 ppm, 40 to 119 ppm, and 45 to 51 ppm, respectively. The Ce 4+ concentrations were under the minimum detection limits for the ICP instrument utilized. The results indicate that the ion release levels may be appropriate to mediate therapeutic effects with respect to peripheral nerve regeneration. The data generated in this paper provides requisite evidence to optimize composition for pre-clinical evaluation of the experimental composite. © 2012 Elsevier B.V

Biodistribution and inflammatory profiles of novel penton and hexon double-mutant serotype 5 adenoviruses

The use of adenovirus serotype 5 (Ad5) vectors in the clinical setting is severely hampered by the profound liver tropism observed after intravascular delivery coupled with the pronounced inflammatory and innate immune response elicited by these vectors. Liver transduction by circulating Ad5 virions is mediated by a high-affinity interaction between the capsid hexon protein and blood coagulation factor X (FX), whilst penton-α(v)integrin interactions are thought to contribute to the induction of anti-Ad5 inflammatory and innate immune responses. To overcome these limitations, we sought to develop and characterise for the first time novel Ad5 vectors possessing mutations ablating both hexon:FX and penton:integrin interactions. As expected, intravascular administration of the FX binding-ablated Ad5HVR5*HVR7*E451Q vector (AdT*) resulted in significantly reduced liver transduction in vivo compared to Ad5. In macrophage-depleted mice, increased spleen uptake of AdT* was accompanied by an elevation in the levels of several inflammatory mediators. However ablation of the penton RGD motif in the AdT* vector background (AdT*RGE) resulted in a significant 5-fold reduction in spleen uptake and attenuated the antiviral inflammatory response. A reduction in spleen uptake and inflammatory activation was also observed in animals after intravascular administration of Ad5RGE compared to the parental Ad5 vector, with reduced co-localisation of the viral beta-galactosidase transgene with MAdCAM-1+ sinus-lining endothelial cells. Our detailed assessment of these novel adenoviruses indicates that penton base RGE mutation in combination with FX binding-ablation may be a viable strategy to attenuate the undesired liver uptake and pro-inflammatory responses to Ad5 vectors after intravascular deliver

Spectrum of Background X-rays from Moduli Dark Matter

We examine the $X$-ray spectrum from the decay of the dark-matter moduli with mass $\sim {\cal O}(100)$keV, in particular, paying attention to the line spectrum from the moduli trapped in the halo of our galaxy. It is found that with the energy resolution of the current experiments ($\sim 10$%) the line intensity is about twice stronger than that of the continuum spectrum from the moduli that spread in the whole universe. Therefore, in the future experiments with higher energy resolutions it may be possible to detect such line photons. We also investigate the $\gamma$-ray spectrum emitted from the decay of the multi-GeV moduli. It is shown that the emitted photons may form MeV-bump in the $\gamma$-ray spectrum. We also find that if the modulus mass is of the order of 10 GeV, the emitted photons at the peak of the continuum spectrum loses their energy by the scattering and the shape of the spectrum is significantly changed, which makes the constraint weaker than that obtained in the previous works.Comment: 14 pages (RevTeX file) including four postscript figures, reviced version to be published in Physical Review