The correlation function of the distribution of matter in the universe shows, at large scales, baryon acoustic oscillations, which were imprinted prior to recombination. This feature was first detected in the correlation function of the luminous red galaxies (LRG) of the Sloan Digital Sky Survey (SDSS). The final release (DR7) of the SDSS has been recently made available, and the useful volume is about two times bigger than in the old sample. We present here, for the first time, the redshift space correlation function of this sample at large scales together with that for one shallower, but denser volume-limited subsample drawn from the 2dF redshift survey. We test the reliability of the detection of the acoustic peak at about 100 h −1 Mpc and the behaviour of the correlation function at larger scales by means of careful estimation of errors. We confirm the presence of the peak in the latest data although broader than in previous detections.

We have developed a method based on wavelets to obtain the true underlying smooth density from a point distribution. The goal has been to reconstruct the density field in an optimal way, ensuring that the morphology of the reconstructed field reflects the true underlying morphology of the point field, which, as the galaxy distribution, has a genuinely multiscale structure, with near-singular behavior on sheets, filaments, and hot spots. If the discrete distributions are smoothed using Gaussian filters, the morphological properties tend to be closer to those expected for a Gaussian field. The use of wavelet denoising provides us with a unique and more accurate morphological description. Subject headingg s: large-scale structure of universe -methods: statistical

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The association of sleep disruption with a higher vulnerability to COVID-19 infection is a subject of major clinical importance. In patients with pneumonia associated with COVID-19 admitted to non-intensive care unit (NICU) several factors, like the disrupting influence of respiratory distress, medication, greater stress due to social isolation, and lack of appropriate exposure to environmental light can be instrumental to disrupt sleep/wake cycle. The therapeutic potential of melatonin to counteract the consequences of COVID-19 infection has been advocated. Because of its wide-ranging effects as an antioxidant, anti-inflammatory, and immunomodulatory compound, melatonin could be unique in impairing the consequences of SARS-CoV-2 infection. Melatonin is also an effective chronobiotic agent to reverse the circadian disruption of social isolation and to control delirium in severely affected patients. Properly administered, melatonin may restore the optimal circadian pattern of the sleep-wake cycle and improve clinical condition in pneumonia associated with COVID-19 patients. The present review article discusses the importance of maintaining normal sleep and circadian rhythmicity in NICU patients and provides preliminary data suggesting the efficacy of melatonin (9 mg/day) to reduce length of stay of pneumonia patients associated with COVID-19 in NICU.

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