Polyculture and growth of the Nile tilapia Oreochromis niloticus (Perciformes:Cichlidae) with shrimp Litopenaeus vannamei (Decapoda:Penaeidae) in sea water

Globally, the tilapia is the second most important group of commercial fish. Polyculture and growth were studied for 181 Nile tilapia, Oreochromis niloticus, in a seawater pond (30-37‰) at a density of 50 fish/m3 for six months (October to April) with 30 shrimp Litopenaeus vannamei at a density of 8 shrimp/m3 in two months (December-February) in an open tank of 3,6 m3. They were fed Camaronina”pellets” at libitum in the morning. The pond bottom was siphoned every other day, was maintained with constant aeration. Water exchange was 80% every two weeks. The temperature varied from 18 to 32oC. The tilapia grew from 72mm to 220mm, and 7g to 232g, survival was 92%. The total biomass was 38,6 kg. The shrimp grew from 6,8 g to 11,5 g and 102mm to 121mm. The survival rate was 100%. Total biomass was 219g. The feed conversion ratio (FCR) was 1,3:1,0 in both species. There was no problem between species; this polyculture is recommended.KEY WORDSPolyculture, growth, Litopenaeus vannamei, Oreochromis niloticus, biomass, densitySe estudió el policultivo y el crecimiento de 181 tilapias del Nilo Oreochromis niloticus en un estanque con agua de mar (30-37‰) a una densidad de 50 peces/m3 en seis meses (octubre a abril) con 30 camarones Litopenaeus vannamei a una densidad de 8 camarones/m3 en dos meses (diciembre-febrero) en un tanque abierto de 3,6 m3. Fueron alimentados “pellets” Camaronina at libitum en la mañana. El fondo del estanque fue sifonado cada tercer día, se mantuvo con aireación constante. El intercambio de agua fue del 80% cada dos semanas. El rango de temperatura varió de 18 a 32oC. La tilapia creció de 72mm a 220mm, y de 7g a 232g, la supervivencia fue del 92%. La biomasa total fue de 38,6 kg. El camarón creció de 6,8g y 102mm a 11,5g y 121mm. La tasa de supervivencia fue del 100%. La biomasa total fue de 219g. La tasa de conversión alimenticia (FCR) fue 1,3:1,0 en ambas especies. No hubo ningún problema entre las especies; se recomienda un policultivo de ambas. PALABRAS CLAVEPolicultivo, crecimiento, Litopenaeus vannamei, Oreochromis nilotica, biomasa, densidad, supervivenci

Leveraging conditional linkage models in gray-box optimization with the real-valued gene-pool optimal mixing evolutionary algorithm

Often, real-world problems are of the gray-box type. It has been shown that the Real-Valued Gene-pool Optimal Mixing Evolutionary Algorithm (RV-GOMEA) is in principle capable of exploiting such a Gray-Box Optimization (GBO) setting using linkage models that capture dependencies between problem variables, resulting in excellent performance and scalability on both benchmark and real-world problems that allow for partial evaluations. However, linkage models proposed for RV-GOMEA so far cannot explicitly capture overlapping dependencies. Consequently, performance degrades if such dependencies exist. In this paper, we therefore introduce various ways of using conditional linkage models in RV-GOMEA. Their use is compared to that of non-conditional models, and to VkD-CMA, whose performance is among the state of the art, on various benchmark problems with overlapping dependencies. We find that RV-GOMEA with conditional linkage models achieves the best scalability on most problems, with conditional models leading to similar or better performance than non-conditional models. We conclude that the introduction of conditional linkage models to RV-GOMEA is an important contribution, as it expands the set of problems for which optimization in a GBO setting results in substantially improved performance and scalability. In future work, conditional linkage models may prove to benefit the optimization of real-world problems.Accepted Author ManuscriptAlgorithmic

Heterozygous nonsense variants in the ferritin heavy-chain gene FTH1 cause a neuroferritinopathy

Summary: Ferritin, the iron-storage protein, is composed of light- and heavy-chain subunits, encoded by FTL and FTH1, respectively. Heterozygous variants in FTL cause hereditary neuroferritinopathy, a type of neurodegeneration with brain iron accumulation (NBIA). Variants in FTH1 have not been previously associated with neurologic disease. We describe the clinical, neuroimaging, and neuropathology findings of five unrelated pediatric patients with de novo heterozygous FTH1 variants. Children presented with developmental delay, epilepsy, and progressive neurologic decline. Nonsense FTH1 variants were identified using whole-exome sequencing, with a recurrent variant (p.Phe171∗) identified in four unrelated individuals. Neuroimaging revealed diffuse volume loss, features of pontocerebellar hypoplasia, and iron accumulation in the basal ganglia. Neuropathology demonstrated widespread ferritin inclusions in the brain. Patient-derived fibroblasts were assayed for ferritin expression, susceptibility to iron accumulation, and oxidative stress. Variant FTH1 mRNA transcripts escape nonsense-mediated decay (NMD), and fibroblasts show elevated ferritin protein levels, markers of oxidative stress, and increased susceptibility to iron accumulation. C-terminal variants in FTH1 truncate ferritin’s E helix, altering the 4-fold symmetric pores of the heteropolymer, and likely diminish iron-storage capacity. FTH1 pathogenic variants appear to act by a dominant, toxic gain-of-function mechanism. The data support the conclusion that truncating variants in the last exon of FTH1 cause a disorder in the spectrum of NBIA. Targeted knockdown of mutant FTH1 transcript with antisense oligonucleotides rescues cellular phenotypes and suggests a potential therapeutic strategy for this pediatric neurodegenerative disorder