Cloud microphysical effects of turbulent mixing and entrainment

Turbulent mixing and entrainment at the boundary of a cloud is studied by means of direct numerical simulations that couple the Eulerian description of the turbulent velocity and water vapor fields with a Lagrangian ensemble of cloud water droplets that can grow and shrink by condensation and evaporation, respectively. The focus is on detailed analysis of the relaxation process of the droplet ensemble during the entrainment of subsaturated air, in particular the dependence on turbulence time scales, droplet number density, initial droplet radius and particle inertia. We find that the droplet evolution during the entrainment process is captured best by a phase relaxation time that is based on the droplet number density with respect to the entire simulation domain and the initial droplet radius. Even under conditions favoring homogeneous mixing, the probability density function of supersaturation at droplet locations exhibits initially strong negative skewness, consistent with droplets near the cloud boundary being suddenly mixed into clear air, but rapidly approaches a narrower, symmetric shape. The droplet size distribution, which is initialized as perfectly monodisperse, broadens and also becomes somewhat negatively skewed. Particle inertia and gravitational settling lead to a more rapid initial evaporation, but ultimately only to slight depletion of both tails of the droplet size distribution. The Reynolds number dependence of the mixing process remained weak over the parameter range studied, most probably due to the fact that the inhomogeneous mixing regime could not be fully accessed when phase relaxation times based on global number density are considered.Comment: 17 pages, 10 Postscript figures (figures 3,4,6,7,8 and 10 are in reduced quality), to appear in Theoretical Computational Fluid Dynamic

Erros de anotações na elaboração de índices de produção em granjas industriais de suínos no Sul do Brasil The human effect on data collection of birth-related production indices in Brazilian swine industrial farms

Foram realizadas observações em quatro granjas de suinocultura industrial nas 24 horas do dia, registrando-se o número de fetos mumificados, de natimortos, de nascidos vivos e total segundo as observações feitas por funcionários da granja (FUN) e por pesquisadores (AO). Foram também registrados resultados de um número semelhante de anotações das mesmas características no período imediatamente anterior à pesquisa, obtidas dos relatórios das granjas. Verificaram-se diferenças entre as avaliações dos FUN e dos AO quanto aos registros dos mumificados e total de nascidos em todas as granjas (P<0,05). A diferença no número de natimortos ocorreu em três granjas (P<0,05) e de nascidos vivos em apenas uma (P<0,05). Os percentuais máximos de mumificados, de natimortos, de nascidos vivos e total não registrados pelos FUN foram 67,8%, 34,5%, 1,8% e 5,1%, respectivamente. Os percentuais máximos das mesmas características não registrados pelos FUN no período imediatamente anterior à pesquisa foram 70,4%, 82,1%, 10,5% e 16,5%.<br>Observational studies were carried out in four industrial swine farms. The observations were performed on a 24 hours basis and mummified fetuses, stillborn and born alive piglets were recorded by observers (OB) and by employees (EM). In all farms, it was also obtained a retrospective data previous to the observational study period, comprising the same number of farrowings. Differences among mummified fetuses and total born piglets recorded by OB and EM in all farms (P<0.05) were observed. The recorded number of stillborn piglets differed between OB and EM in three farms (P<0.05) and the number of born alive piglets in one unit (P<0.05). In all farms during the analysis period, the maximal percentage of recorded mummified fetuses, stillborn, born alive and total born piglets, were 67.8%, 34.5%, 1.8% and 5.1%, respectively. The comparison of retrospective and EM data showed a maximal percentage of not recorded mummified fetuses, stillborn, born alive and total born piglets by EM of 70.4%, 82.1%, 10.5% e 16.5%, respectively. These errors can induce to a wrong interpretation of the farm data and the efforts to maximize the productivity could be directed to other sectors than the farrowing house

Genome sequences of two diploid wild relatives of cultivated sweetpotato reveal targets for genetic improvement

Sweetpotato [Ipomoea batatas (L.) Lam.] is a globally important staple food crop, especially for sub-Saharan Africa. Agronomic improvement of sweetpotato has lagged behind other major food crops due to a lack of genomic and genetic resources and inherent challenges in breeding a heterozygous, clonally propagated polyploid. Here, we report the genome sequences of its two diploid relatives, I. trifida and I. triloba, and show that these high-quality genome assemblies are robust references for hexaploid sweetpotato. Comparative and phylogenetic analyses reveal insights into the ancient whole-genome triplication history of Ipomoea and evolutionary relationships within the Batatas complex. Using resequencing data from 16 genotypes widely used in African breeding programs, genes and alleles associated with carotenoid biosynthesis in storage roots are identified, which may enable efficient breeding of varieties with high provitamin A content. These resources will facilitate genome-enabled breeding in this important food security crop