In this paper we examine the cosmological consequences of fourth order Galileon gravity. We carry out detailed investigations of the underlying dynamics and demonstrate the stability of one de Sitter phase. The stable de Sitter phase contains a Galileon field which is an increasing function of time ( _ > 0). Using the required suppression of the fifth force, supernovae, Baryon acoustic oscillations, and CMB data, we constrain parameters of the model. We find that the matter coupling parameter is constrained to small numerical values such that < 0:02. We also show that the parameters of the third and fourth order in the action ðc 3 ; c 4 Þ are not independent and with reasonable assumptions, we obtain constraints on them. We investigate the growth history of the model and find that the subhorizon approximation is not allowed for this model. We demonstrate strong scale dependence of linear perturbations in the fourth order Galileon gravity.

In this paper, we examine the cosmological viability of a light mass galileon field consistent with local gravity constraints. The minimal, L3 = φ(∂µφ) 2 , massless galileon field requires an additional term in order to give rise to a viable ghost free late time acceleration of Universe. The desired cosmological dynamics can either be achieved by incorporating an additional terms in the action such as (L4, L5) − the higher order galileon Lagrangians or by considering a light mass fieldà la galileon field potential. We analyse the second possibility and find that: (1) The model produces a viable cosmology in the regime where the non-linear galileon field is subdominant, (2) The Vainshtein mechanism operates at small scales where the non-linear effects become important and contribution of the field potential ceases to be significant. Also the small mass of the field under consideration is protected against strong quantum corrections thereby providing quantum stability to the system.

Objectives Systemic vasculitis is often mistakenly assumed to be a common cause of retinal vasculitis. We sought to determine the relationship between retinal vasculitis and systemic vasculitis. Methods A selected review was performed on 1390 charts of patients attending the uveitis clinic at the Oregon Health & Science University between 1985 and 2010. Included in the review were all patients with diagnoses commonly associated with retinal vasculitis and all patients who were diagnosed with a systemic vasculitis. Retinal vasculitis was identified by perivascular exudates, intraretinal hemorrhage, or cotton wool spots as seen on clinical examination or by vascular occlusion or leakage as identified by fluorescein angiogram. Results 207 or 14.9% of patients with uveitis had retinal vasculitis as a component of the intraocular inflammation. Thirty-five patients had retinal vasculitis which was primary, i.e. not associated with a systemic disease, and the dominant manifestation of the uveitis. Fourteen of the patients with retinal vasculitis had Behcet’s disease. Only 11 of the 1390 patients with uveitis had a systemic vasculitis. Of these 11, four had retinal vasculitis including one secondary to a CMV retinitis. Thus, systemic vasculitis was directly responsible for 1.4% or 3 of 207 cases of retinal vasculitis. No-vasculitic systemic diseases such as sarcoidosis (n=13), syndromes confined to the eye such as pars planitis (n=36), and intraocular infections (n=29) were far more common causes of retinal vasculitis. Conclusion Retinal vasculitis is a relatively common feature of uveitis. Patients with retinal vasculitis, however, rarely suffer from one of the classical systemic vasculitides.

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In this paper, we carry out a study of viable cosmological models in f (R)-gravity at the background level. We use observable parameters like Ω and γ to form autonomous system of equations and show that the models under consideration exhibit two different regimes in their time evolution, namely, a phantom phase followed by a quintessence like behavior. We employ statefinder parameters to emphasize a characteristic discriminative signature of these models.

Aims: To compare the safety and efficacy of 2 anti-vascular-endothelial-growth-factor agents – bevacizumab (Avastin) versus ranibizumab (Lucentis) – in the treatment of patients with neovascular age-related macular degeneration (AMD). Methods: Retrospective analysis of patients who received intravitreal injections of bevacizumab or ranibizumab for neovascular AMD. Primary outcome measures were best-corrected visual acuity (BCVA) and central foveal thickness (CFT) assessed by Spectral Domain scanning laser ophthalmoscope-optical coherence tomography (SD-OCT). A secondary outcome measure was the report of any adverse events in the 2 groups. Results: The number of injections in the bevacizumab group was 184 (average of 4.7 per eye) compared to 187 in the ranibizumab group (average of 5.5 per eye). The mean logMAR equivalent of BCVA at 1 month after the injection improved by 0.18 in the bevacizumab group (p = 0.009) and by 0.13 in the ranibizumab group (p = 0.004). The average SD-OCT CFT decreased from 325 ± 72 to 300 ± 69 μm in the bevacizumab group (p = 0.016) and from 307 ± 57 to 289 ± 56 μm in the ranibizumab group (p = 0.017). In the bevacizumab group, there was 1 event of lower extremity pain (0.54%) and 1 event of increased arterial blood pressure (0.54%). In the ranibizumab group, there were 2 events of transiently increased intraocular pressure (1.1%) and 1 event (0.53%) of intraocular inflammation following injection. Conclusions: Bevacizumab and ranibizumab treatments resulted in similar gains in visual acuity and reduction in macular thickness, documented each month following injection. Intravitreal bevacizumab appears to be as safe and effective as intravitreal ranibizumab in the treatment of exudative AMD.

The string inspired tachyon field can serve as a candidate of dark energy. Its equation of state parameter w varies from 0 to −1. In case of tachyon field potential V (φ) → 0 slower(faster) than 1/φ 2 at infinity, dark energy(dark matter) is a late time attractor. We investigate the tachyon dark energy models under the assumption that w is close to −1. We find that all the models exhibit unique behavior around the present epoch which is exactly same as that of the thawing quintessence.

Uveitis, a leading cause of blindness, is among the most common eye manifestations in patients affected by seronegative spondyloarthropathies. Evidence suggests both genetic and environmental factors in its pathogenesis. Immunomodulator treatments, including the recently popular biologics, may be effective in the control of chronic uveitis in patients with spondyloarthropathy. Ocular surgery is often needed in these patients, and appropriate cautions are required in order to achieve successful vision rehabilitation.