Papers by Anthony Williams
Journal of High Energy Physics
Charged Higgs bosons are predicted in variety of theoretically well-motivated new physics models ... more Charged Higgs bosons are predicted in variety of theoretically well-motivated new physics models with extended Higgs sectors. In this study, we focus on a type-II two Higgs doublet model (2HDM-II) and consider a heavy charged Higgs with its mass ranging from 500 GeV to 1 TeV as dictated by the b → sγ constraints which render M H ± > 480 GeV. We study the dominant production mode H ± t associated production with H ± → W ± A being the dominant decay channel when the pseudoscalar A is considerably lighter. For such a heavy charged Higgs, both the decay products W ± and A are relatively boosted. In such a scenario, we apply the jet substructure analysis of tagging the fat pseudoscalar and W jets in order to eliminate the standard model background efficiently. We perform a detailed detector simulation for the signal and background processes at the 14 TeV LHC. We introduce various kinematical cuts to determine the signal significance for a number of benchmark points with charged Higgs boson mass from 500 GeV to 1 TeV in the W ± A decay channel. Finally we perform a multivariate analysis utilizing a boosted decision tree algorithm to optimize these significances.
Clinical immunology (Orlando, Fla.), Oct 18, 2016
PloS one, 2016
The recently described Mucosal Associated Invariant T (MAIT) cells mediate specific recognition o... more The recently described Mucosal Associated Invariant T (MAIT) cells mediate specific recognition of bacterial and fungal vitamin B2 metabolites. As innate T cells, they possess broad effector responses, including IFN- including Iproduction, that are comparable to conventional T cell responses. Immunodeficiencies associated with systemic Th17 deficiency may also be compounded by defects in MAIT immunity. We evaluated Th17 immunity in this innate T cell compartment in primary (AD-HIES) and secondary immunodeficiency (thymoma) patients with conventional Th17 deficiency and susceptibility to fungal and bacterial disease. Our results suggest that MAIT cells are both reduced and functional deficient in STAT3 deficiency and thymoma patients with IL-12/23 autoantibodies. In contrast, thymoma patients without autoantibodies preserved the normal number and functional MAIT cells.
Cancer Immunology Research, 2015
Reproduction, nutrition, development, 1995
Four naturally born lambs were placed in sterile isolators 24 h after birth, before the natural e... more Four naturally born lambs were placed in sterile isolators 24 h after birth, before the natural establishment of the cellulolytic microorganisms. At the age of 4 weeks, a cellulolytic bacterial population of approximately 10(8) cells g-1 of rumen contents was established by inoculation with a 10(-6) dilution of ruminal contents taken from an adult sheep. A pure culture of Neocallimastix frontalis MCH3 and Piromyces communis FL was inoculated into the rumen 5 months after birth and a stable population of 10(3)-10(4) zoospores g-1 developed; the cellulolytic bacteria and fungi established populations in the 4 lambs that were similar to those observed in conventional animals. The presence of fungi led to an increase in the activity of most of the glycoside and polysaccharide hydrolases of the particle-associated microbial populations. However, this effect was not accompanied by an increase in the in sacco degradation of wheat straw or an increase in the volatile fatty acid concentratio...
Radiation protection dosimetry, Jan 11, 2015
A short-term sensitivity loss in LiF:Mg,Cu,P thermoluminescent dosemeters (TLDs) was observed and... more A short-term sensitivity loss in LiF:Mg,Cu,P thermoluminescent dosemeters (TLDs) was observed and is described. Its observation occurred during a pre-irradiation anneal with a slightly elevated maximum temperature (5-15°C), which causes notable under-response (5-10 %) of the subsequent read at the recommended time-temperature profile (TTP), which has a peak temperature of 260°C. A subsequent irradiation and reading using the recommended TTP showed partial or complete recovery of the TLD's sensitivity. To the best of our knowledge, there were no publications on possible implications of a one-time 5-15°C overheat of LiF:Mg,Cu,P TLDs during anneal. This is not unusual when several readers with some variations in their heating cycles are used to calibrate and process the same population of dosemeters. A special test to identify if a small uncontrolled overheating of a dosemeter element has occurred was developed and tested. Two practical implications of the effect of a short-term se...
Facilitating Literature-Based Discovery, 2008
The communication of chemistry-related information occurs both via print and electronic media and... more The communication of chemistry-related information occurs both via print and electronic media and chemical entities can appear as structure depictions or, more commonly, as systematic names (commonly either IUPAC 1 or CAS 2 names), as trade names or of one of a plethora of registry numbers (CAS 3 , EINECS/ EC-number 4 or others). The preferable form of communication for a chemist is via a depiction of the chemical structure with an electronic molecular connection table as its basis. Electronic representations of chemical structures are one of the informatics underpinnings for any organization operating in the domain of chemistry or biology and enable the creation of a structure/substructure searchable database of chemical structures and associated data and knowledge. There is an enormous wealth of information embedded inside both print and electronic documents in the form of chemical names and a means by which to convert those alphanumeric text descriptors into a more rich chemical structure representation has long been the mission of a large group of investigators. The challenges and hurdles to success are quite profound in their nature. We will review the present state of this research and the efforts underway to recover the value of information textually trapped in publications, patents, databases and Internet pages across the multiple domains of chemistry.
Physical Review D, 2011
We study the behavior of the AsqTad quark propagator in Landau gauge on SU(3) Yang-Mills gauge co... more We study the behavior of the AsqTad quark propagator in Landau gauge on SU(3) Yang-Mills gauge configurations under the removal of center vortices. In SU(2) gauge theory, center vortices have been observed to generate chiral symmetry breaking and dominate the infrared behavior of the quark propagator. In contrast, we report a weak dependence on the vortex content of the gauge configurations, including the survival of dynamical mass generation on configurations with vanishing string tension.
We report on the observation of superconducting energy gap suppression by resonant scattering. Tu... more We report on the observation of superconducting energy gap suppression by resonant scattering. Tunneling measurements of dilute Al-Mn alloys demonstrate the absence of density-of-states smearing that accompanies pair breaking and verify the detailed predictions of the Kaiser resonant scattering theory. These materials represent model systems for quasi-particle scattering and interference phenomena in the high- temperature superconductors.
In Australia, as well as internationally, Universities are looking to ensure the quality of their... more In Australia, as well as internationally, Universities are looking to ensure the quality of their graduates through the development of graduate attributes. In the engineering domain there exists Professional Institution defined graduate attributes, which graduates require to effectively participate in the engineering profession. One of the primary attributes is the ability to communicate effectively. This paper explores what this might
Proceedings of SPIE - The International Society for Optical Engineering, 2006
In the past few years, several studies have explored the topology of interactions in different co... more In the past few years, several studies have explored the topology of interactions in different complex systems. Areas of investigation span from biology to engineering, physics and the social sciences. Although having different microscopic dynamics, the results demonstrate that most systems under consideration tend to self-organize into structures that share common features. In particular, the networks of interaction are characterized by a power law distribution, P (k) ∼ k −α , in the number of connections per node, k, over several orders of magnitude. Networks that fulfill this propriety of scale-invariance are referred to as "scale-free". In the present work we explore the implication of scale-free topologies in the antiferromagnetic (AF) Ising model and in a stochastic model of opinion formation. In the first case we show that the implicit disorder and frustration lead to a spinglass phase transition not observed for the AF Ising model on standard lattices. We further illustrate that the opinion formation model produces a coherent, turbulent-like dynamics for a certain range of parameters. The influence, of random or targeted exclusion of nodes is studied.
Physical Review D, 2007
In this work we examine the Fat-Link Irrelevant Clover (FLIC) overlap quark propagator and the gl... more In this work we examine the Fat-Link Irrelevant Clover (FLIC) overlap quark propagator and the gluon propagator on both dynamical and quenched lattices. The tadpole-improved Luscher-Weisz gauge action is used in both cases. The dynamical gauge fields use the FLIC fermion action for the sea quark contribution. We observe that the presence of sea quarks causes a suppression of the mass function, quark renormalization function and gluon dressing function in the infrared. The ultraviolet physics is unaffected.
Nature Precedings, 2010
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Journal of Experimental Biology, 2009
It is axiomatic that whole-animal metabolism, measured for example as daily energy expenditure (D... more It is axiomatic that whole-animal metabolism, measured for example as daily energy expenditure (DEE), plays a central role in determining reproductive success and survival (fitness) in all organisms. Nevertheless, strong evidence for consistent systematic relationships between DEE and either individual traits (age, sex, body size), environmental factors (e.g. food availability, temperature) or 'fitness' traits (e.g. number of offspring, survival) remains far from compelling in birds and mammals. Recently, we suggested that female birds might utilise complex, individually variable energy management strategies to meet the metabolic demands of reproduction, generating a wide spectrum of effects on reproductive DEE, from overcompensation (net decrease in DEE) to additive effects (net increase in DEE). Here we show that this individually variable adjustment or 'plasticity' in energy expenditure associated with egg production is repeatable among individuals between successive breeding attempts in female zebra finches (Taeniopygia guttata). Our study highlights the importance (a) of measuring 'plasticity' or change associated with transitions of physiological state (e.g. non-breeding to breeding) based on multiple measurements of the same individual, and (b) of extending consideration of how selection might drive the evolution of phenotypic plasticity per se to include physiological and metabolic traits.
Journal of Experimental Biology, 2007
Tetrahedron, 2005
A method for elucidation of the relative stereoconfiguration of natural product molecular structu... more A method for elucidation of the relative stereoconfiguration of natural product molecular structures and their 3D models based on NOE data and the application of a genetic algorithm is described. The method is applicable mainly for rigid polycyclic structures commonly encountered in natural products. It is demonstrated that the technique of simulated annealing cannot be easily used when dealing with lowweight fused ring molecules but the application of a genetic algorithm is proven successful. Examples of a typical genetic algorithm workflow and the optimization of the algorithmic parameters are discussed. The efficiency of the approach developed here is demonstrated on the complex natural products of both Taxol w (C 47 H 51 NO 14) and brevetoxin B (C 50 H 70 O 14).
Polar Biology, 2012
It has long been held that Eudyptes penguins will only ever develop a maximum of two mature yolky... more It has long been held that Eudyptes penguins will only ever develop a maximum of two mature yolky follicles to match their invariant two-egg clutch, an idea inferred largely from egg removal studies. Combining our own data with those from a previous but rarely cited study and by applying these to a simple developmental model, we show that macaroni penguins (Eudyptes chrysolophus) develop up to four large, yolky vitellogenic follicles, and they do so despite the fact that they will never lay more than two eggs or rear more than one chick, a tactic that seems maladaptive given their realized reproductive success. We discuss these results within the context of the usual pattern of reproductive investment in Eudyptes penguins and suggest a broader significance to modes of clutch size determination among all penguins (order Sphenisciformes).
Physiology & Behavior, 2003
Several lines of evidence support a role for reduced melanocortin signaling in the regulation of ... more Several lines of evidence support a role for reduced melanocortin signaling in the regulation of metabolic rate and cardiovascular function during negative energy balance. We tested the hypothesis that agouti yellow (B6.Cg-A y) mice would exhibit blunted physiologic responses to fasting and thermoneutrality. Male B6.Cg-A y mice (A y ; n = 11, 34 ± 2 g) and lean B6 littermates (B6; n = 7, 26 ± 2 g) were implanted with telemetry devices and housed in metabolic chambers (T a = 23°C) to determine the effects of a 24-h fasting and exposure to thermoneutrality (T a = 30°C) on mean arterial pressure (MAP), heart rate (HR), AP and HR variability (time and frequency domain), oxygen consumption (VO 2), and locomotor activity. A y mice exhibited elevated baseline light-period MAP (A y : 113 ± 4; B6: 99 ± 3 mm Hg) and VO 2 (A y : 1.82 ± 0.08 vs. B6: 1.45 ± 0.13 ml/min) with no difference in HR (A y : 530 ± 12 vs. B6: 548 ± 19 bpm). At 12-24 h after food removal, A y mice displayed normal fasting-induced bradycardia (A y : À 106 ± 12; B6: À 117 ± 19 bpm) and reduction in VO 2 (A y : À 0.19 ± 0.04 vs. B6: À 0.28 ± 0.05 ml/min), but with augmented hypotension (A y : À 9 ± 2 vs. B6: À 0.5 ± 2 mm Hg) and blunted hyperactivity (A y : 27 ± 23 vs. B6: 122 ± 42 m/11 h). Fasting was associated with increased HR variability in both time and frequency domain in B6 but not A y mice. Exposure to thermoneutrality produced comparable reductions in MAP, HR, and VO 2 in both strains. We conclude that inhibition of melanocortin signaling is not requisite for, but participates in, the metabolic and cardiovascular responses to negative energy balance.
Physiological and Biochemical Zoology, 2007
The relationship between egg size and offspring phenotype is critical to our understanding of the... more The relationship between egg size and offspring phenotype is critical to our understanding of the selective pressures acting on the key reproductive life-history traits of egg size and number. Yet there is surprisingly little empirical evidence to support a strong, positive relationship between egg size and offspring quality (i.e., offspring growth, condition, and survival) in birds, in part because of confounding effects of parental quality and the lack of experimental techniques for directly manipulating avian egg size independently of maternal condition. Previously, we showed that treatment of laying female zebra finches (Taeniopygia guttata) with the antiestrogen tamoxifen can decrease egg size by ca. 8% but that this reduction in egg size had few effects on offspring mass and size at fledging. Here, we extend the use of this technique to induce larger decreases in egg size (up to 50% in individual females) and show that a reduction in egg size of ca. 18% is associated with decreased embryo viability, increased hatchling mortality, and lower posthatching offspring survival. Furthermore, we show that although hatchlings from eggs reduced in size by ca. 9% can survive to fledging, these chicks show slower initial growth during the linear growth phase (5-10 d of age), fledge at lower masses than chicks from control eggs, and show postfledging compensatory growth. Our results provide empirical support for significant effects of egg size on offspring quality and further suggest that among individual females there is a minimum egg size required to maintain embryo viability and offspring quality.
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Papers by Anthony Williams