Exact cosmological solutions for MOG

We find some new exact cosmological solutions for the covariant scalar-tensor-vector gravity theory, the so-called MOdified Gravity (MOG). The exact solution of the vacuum field equations has been derived. Also, for non vacuum cases we have found some exact solutions with the aid of the Noether symmetry approach. More specifically, the symmetry vector and also the Noether conserved quantity associated to the point-like Lagrangian of the theory have been found. Also we find the exact form of the generic vector field potential of this theory by considering the behavior of the relevant point-like Lagrangian under the infinitesimal generator of the Noether symmetry. Finally, we discuss the cosmological implications of the solutions.Comment: 8 pages, to appear in European Physical Journal

Rise of the Renter Nation: Solutions to the Housing Affordability Crisis

Private homeownership cannot serve as our only model for decent, stable housing. While the most recent speculative bubble raised the proportion of homeowners nationwide to 70 percent of all households, this gain was an illusion that vanished as the market collapsed. A longer view reveals that for three decades before the bubble began in the mid-1990s, homeownership rates hovered around 64 percent, despite massive federal and market support. Further, the historic average obscures important and severe racial disparities in homeownership rates, which have never exceeded 50 percent for black and Latino populations. Yet, policy and even much of the progressive analysis of the housing crisis seem incapable of acknowledging -- much less acting on -- these realities. The result is a national dialogue about the housing crisis that all but ignores the growing renter class, where the crisis is concentrated, and retains a myopic focus on private ownership. The following report is a reality check. It attempts to redirect the conversation and provide an agenda for genuine housing security for all

Smile wide with pride: outcomes of an oral health promotion project among Aboriginal opiate treatment program clients

Examines the effectiveness of oral health promotion programs among Indigenous opiate treatment program clients and analyses dental appointment compliance in this population. Introduction Drug abuse is a significant issue for society with drug-related crimes continuing to be a significant social problem. Oral hygiene goes way down the priority list for these people and while drug users are an at-risk group with regards to oral health, their dependants are at a higher risk because of sub-standard diet and oral hygiene practices due to their parents’ dysfunctional state during their period of addiction. Drug abuse in Aboriginal families would be expected to have a more deleterious effect on the oral health of their families than it would in non-Aboriginal families, because the level of baseline risk for dental diseases is higher among Aboriginal communities. Various studies including the second National oral health survey (2004-2006) have shown that Aboriginal Australians have poorer oral health when compared to other Australians. A recent study has established that the oral health related quality of life in Aboriginal Australians was poor with all risk factors (socio-economic, dental service utilisation, financial and dental self-care factors) amenable to change. Methadone users often have very severe dental pathology (including periodontal disease) at younger ages when compared to the general population. High rates of caries exist among people with opiate dependencies due to a complex, dynamic combination of diet and other factors. They exhibit heightened dental fear. Opiate treatment program (OTP) clients in Port Macquarie and Kempsey, especially Aboriginal clients, demonstrated a lack of knowledge of good oral hygiene practices, lack of awareness of their own dental condition and lack of understanding of the criteria for public dental services, placing them and their dependants at a very high risk for oral disease. OTP clients commonly present as dental emergencies. Approximately 10% of OTP clients in Port Macquarie and 25% in Kempsey are Aboriginal. OTP clients often contact dental services for emergency dental treatment, mostly when it is too late and there are no other systematic approaches to their problem. In this study a systematic approach to dental health education was tailored to OTP clients in Port Macquarie and Kempsey. The specific aim of this study was to determine whether an oral health promotion program accompanied by assessment and comprehensive dental treatment would improve oral health awareness and behaviours. The study also examined compliance with dental appointments among OTP clients. &nbsp

Jeans analysis in modified gravity

MOdified Gravity (MOG) is a covariant modification of Einstein's general relativity. This theory is one of the current alternatives to dark matter models. We describe dynamics of collisionless self-gravitating systems in the context of MOG. By studying the weak field approximation of this theory, we derive the equations governing the dynamics of the self-gravitating systems. More specifically, we consider the Jeans instability for self-gravitating fluid and stellar systems, and derive new Jeans mass limit $\tilde{M}_J$ and wave-number $\tilde{k}_J$. Furthermore, considering the gravitational instability in star forming regions, we show that MOG has not a significant difference with general relativity on this astrophysical scale. However, at larger scales such as intergalactic space MOG may lead to different galaxy and structure formation processes

Exact cosmological solutions from Hojman conservation quantities

We present a new approach to find exact solutions for cosmological models. By requiring the existence of a symmetry transformation vector for the equations of motion of the given cosmological model (without using either Lagrangian or Hamiltonian), one can find corresponding Hojman conserved quantities. With the help of these conserved quantities, the analysis of the cosmological model can be simplified. In the case of quintessence scalar-tensor models, we show that the Hojman conserved quantities exist for a wide range of V(\phi)-potentials and allow to find exact solutions for the cosmic scale factor and the scalar field. Finally, we investigate the general cosmological behavior of solutions by adopting a phase-space view.Comment: 11 pages, 13 figures, accepted for publication in Phys. Lett.