Low-latitude boundary layer clouds as seen by CALIPSO

The distribution of low-level cloud in the tropical belt is investigated using 6 months of Level 2 retrievals from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) at 333 m and 1 km horizontal resolutions. Regional patterns of tropical clouds emerge from the data, matching expectations from existing observations. The advantage of the lidar is highlighted by the distribution of cloud-top height, revealing the preponderance of low-level clouds over the tropical oceans. Over land, cloud top is more uniformly distributed under the influence of diurnal variation. The integrated cloud-top distribution suggests tropical, marine low-cloud amount around 25-30%; a merged CALIPSO-CloudSat product has a similar cloud-top distribution and includes a complementary estimate of cloud fraction based on the lidar detections. The low-cloud distribution is similar to that found in fields of shallow cumulus observed during the Rain in Cumulus Over the Ocean (RICO) field study. The similarity is enhanced by sampling near the RICO site or sampling large-scale conditions similar to those during RICO. This finding shows how satellite observations can help to generalize findings from detailed field observations

Carbonização da casca de arroz para utilização em substratos destinados a produção de mudas.

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Produção de sementes pré-básicas de batata em sistema hidropônico de telhas de fibrocimento: densidade de plantas para multiplicação a partir de minitubérculos.

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Bopp-Podolsky black holes and the no-hair theorem

Bopp-Podolsky electrodynamics is generalized to curved space-times. The equations of motion are written for the case of static spherically symmetric black holes and their exterior solutions are analyzed using Bekenstein's method. It is shown the solutions split-up into two parts, namely a non-homogeneous (asymptotically massless) regime and a homogeneous (asymptotically massive) sector which is null outside the event horizon. In addition, in the simplest approach to Bopp-Podolsky black holes, the non-homogeneous solutions are found to be Maxwell's solutions leading to a Reissner-Nordstr\"om black hole. It is also demonstrated that the only exterior solution consistent with the weak and null energy conditions is the Maxwell's one. Thus, in light of energy conditions, it is concluded that only Maxwell modes propagate outside the horizon and, therefore, the no-hair theorem is satisfied in the case of Bopp-Podolsky fields in spherically symmetric space-times.Comment: 9 pages, updated to match published versio