Dark Energy and the mass of galaxy clusters

Up to now, Dark Energy evidences are based on the dynamics of the universe on very large scales, above 1 Gpc. Assuming it continues to behave like a cosmological constant $\Lambda$ on much smaller scales, I discuss its effects on the motion of non-relativistic test-particles in a weak gravitational field and I propose a way to detect evidences of $\Lambda \neq 0$ at the scale of about 1 Mpc: the main ingredient is the measurement of galaxy cluster masses.Comment: 5 pages, no figures, references adde

Observational Constraints on Silent Quartessence

We derive new constraints set by SNIa experiments (`gold' data sample of Riess et al.), X-ray galaxy cluster data (Allen et al. Chandra measurements of the X-ray gas mass fraction in 26 clusters), large scale structure (Sloan Digital Sky Survey spectrum) and cosmic microwave background (WMAP) on the quartessence Chaplygin model. We consider both adiabatic perturbations and intrinsic non-adiabatic perturbations such that the effective sound speed vanishes (Silent Chaplygin). We show that for the adiabatic case, only models with equation of state parameter $|\alpha |\lesssim 10^{-2}$ are allowed: this means that the allowed models are very close to \LambdaCDM. In the Silent case, however, the results are consistent with observations in a much broader range, -0.3<\alpha<0.7.Comment: 7 pages, 12 figures, to be submitted to JCA

Intravitreal triamcinolone, bevacizumab and pegaptanib for occult choroidal neovascularization.

PURPOSE: To evaluate best-corrected visual acuity (BCVA) and foveal thickness (FT) changes in occult subfoveal choroidal neovascularization (CNV) from age-related macular degeneration (AMD) after intravitreal bevacizumab (IVB, 1.25 mg/0.05 ml), pegaptanib (IVP, 0.3 mg/0.09 ml) and triamcinolone acetonide (IVTA, 4 mg/0.1 ml) injected on an as needed basis. METHODS:   Retrospective, interventional, comparative study. BCVA (Early Treatment Diabetic Retinopathy Study LogMAR) and FT by optical coherence tomography (OCT) were evaluated during 12 months from first treatment. Patients were retreated if signs of neovascular activity were still present on angiography or OCT. RESULTS: Forty-eight eyes received IVB, 43 eyes received IVP, 52 eyes received IVTA. BCVA and FT at baseline were 1.22 ± 0.49 LogMAR and 410.2 ± 41.83 μm in the IVB group, 1.25 ± 0.43 LogMAR and 452.3 ± 44.83 μm in the IVP group and 1.31 ± 0.4 LogMAR and 456.6 ± 48.27 μm in the IVTA group. BCVA and FT improved in the three groups during follow-up. A significantly greater improvement of BCVA was present at month-3, month-6 and at month-12 in the IVB and IVP groups (p = 0.01). Improvement of FT was greater in the IVTA group at month-3 (p = 0.02), while it was greater in the anti-Vascular Endothelial Growth Factor (VEGF) groups at month-6 and month-12 (p = 0.01). A postoperative increase of intraocular pressure was detected in 9/52 (17.3%) eyes treated with IVTA, and in two cases it was resistant to topical therapy. CONCLUSION:   Intravitreal injection of anti-VEGF drugs administered on an as needed basis for AMD-related occult CNVs provided functional and anatomic improvement during 12 months of follow-up

Scalar tilt from broken conformal invariance

Within recently proposed scenario which explains flatness of the spectrum of scalar cosmological perturbations by a combination of conformal and global symmetries, we discuss the effect of weak breaking of conformal invariance. We find that the scalar power spectrum obtains a small tilt which depends on both the strength of conformal symmetry breaking and the law of evolution of the scale factor

Enhancing research culture in academia: a spotlight on early career researchers

This editorial highlights common challenges faced by early career researchers (ECRs) who play a crucial role in our research community. We propose that enhancing the experiences of ECRs will yield benefits to the entire scientific community and we give practical suggestions on how such improvements may be achieved

SETD5 Gene Haploinsufficiency in Three Patients With Suspected KBG Syndrome

Mendelian disorders of the epigenetic machinery (MDEMs), also named chromatin modifying disorders, are a broad group of neurodevelopmental disorders, caused by mutations in functionally related chromatin genes. Mental retardation autosomal dominant 23 (MRD23) syndrome, due to SETD5 gene mutations, falls into this group of disorders. KBG syndrome, caused by ANKRD11 gene haploinsufficiency, is a chromatin related syndrome not formally belonging to this category. We performed high resolution array CGH and trio-based WES on three molecularly unsolved patients with an initial KBGS clinical diagnosis. A de novo deletion of 116 kb partially involving SETD5 and two de novo frameshift variants in SETD5 were identified in the patients. The clinical re-evaluation of the patients was consistent with the molecular findings, though still compatible with KBGS due to overlapping phenotypic features of KBGS and MRD23. Careful detailed expert phenotyping ascertained some facial and physical features that were consistent with MRD23 rather than KBGS. Our results provide further examples that loss-of-function pathogenic variants in genes encoding factors shaping the epigenetic landscape, lead to a wide phenotypic range with significant clinical overlap. We recommend that clinicians consider SETD5 gene haploinsufficiency in the differential diagnosis of KBGS. Due to overlap of clinical features, careful and detailed phenotyping is important and a large gene panel approach is recommended in the diagnostic workup of patients with a clinical suspicion of KBGS

Factors Associated With Asthma Control in 121 Preschool Children

Background: Data on risk factors for uncontrolled asthma in preschool children are controversial. Objective: This study aims to explore the association between clinical and functional parameters and the lack of asthma control in preschool children. Methods: Children aged 3-5 years with asthma and healthy controls were recruited. A questionnaire was used to identify potential risk factors for uncontrolled asthma, as defined by the Global INitiative for Asthma criteria. Lung function and bronchial reversibility were evaluated through impulse oscillometry and spirometry. Adjusted odds ratios were estimated based on multivariable generalized additive regression models. The discriminative ability of the models was measured by the area under the receiver operating characteristic curve (AUC). Results: The study population comprised 121 children (107 with asthma and 14 healthy controls). Fifty-three patients (50%) had uncontrolled asthma. After adjustment, the variables associated with an increased risk of lack of control were as follows: “More than 3 flare-ups in the last 12 months”, “Moderate to severe rhinitis”, and “Relative variation in postbronchodilator FVC and FEV1”. The AUC of the final models that included variation in FVC or FEV1 were 0.82 and 0.81, respectively. The R5-20, R5-20%, and AX z-score values of the healthy group were lower than those of children with asthma. Conclusion: In preschool children, clinical and functional parameters are associated with uncontrolled asthma. More studies are needed to confirm the usefulness of impulse oscillometry.info:eu-repo/semantics/publishedVersio

Are Kaluza-Klein modes enhanced by parametric resonance?

We study parametric amplification of Kaluza-Klein (KK) modes in a higher $D$-dimensional generalized Kaluza-Klein theory, which was originally considered by Mukohyama in the narrow resonance case. It was suggested that KK modes can be enhanced by an oscillation of a scale of compactification by the $d$-dimensional sphere $S^d~(d=D-4)$ and by the direct product $S^{d_1}\times S^{d_2}~(d_1+d_2=D-4)$. We extend this past work to the more general case where initial values of the scale of compactification and the quantum number of the angular momentum $l$ of KK modes are not small. We perform analytic approaches based on the Mathieu equation as well as numerical calculations, and find that the expansion of the universe rapidly makes the KK field deviate from instability bands. As a result, KK modes are not enhanced sufficiently in an expanding universe in these two classes of models.Comment: 15 pages, 5 figure

Restoring the sting to metric preheating

The relative growth of field and metric perturbations during preheating is sensitive to initial conditions set in the preceding inflationary phase. Recent work suggests this may protect super-Hubble metric perturbations from resonant amplification during preheating. We show that this possibility is fragile and sensitive to the specific form of the interactions between the inflaton and other fields. The suppression is naturally absent in two classes of preheating in which either (1) the vacua of the non-inflaton fields during inflation are deformed away from the origin, or (2) the effective masses of non-inflaton fields during inflation are small but during preheating are large. Unlike the simple toy model of a $g^2 \phi^2 \chi^2$ coupling, most realistic particle physics models contain these other features. Moreover, they generically lead to both adiabatic and isocurvature modes and non-Gaussian scars on super-Hubble scales. Large-scale coherent magnetic fields may also appear naturally.Comment: 6 pages, 3 ps figures, RevTex, revised discussion of backreaction and new figure. To appear Phys. Rev. D (Rapid Communication