The architecture of information processing in biological systems

Biological systems process information at different scales and adapt to their changing environment. Informed both by experimental observations and theoretical constraints, we propose a chemical model for sensing that incorporates energy consumption, information storage, and negative feedback. We show that a biochemical architecture enclosing these minimal mechanisms leads to the emergence of dynamical memory and adaptation. Crucially, adaptation is associated with both an increase in the mutual information between external and internal variables and a reduction of dissipation of the internal chemical processes. By simultaneously minimizing energy consumption and maximizing information, we find that far-from-equilibrium sensing dominates in the low-noise regime. Our results, in principle, can be declined at different biological scales. We employ our model to shed light on large-scale neural adaptation in zebrafish larvae under repeated visual stimulation. We find striking similarities between predicted and observed behaviors, capturing the emergent adaptation of neural response. Our framework draws a path toward the unraveling of the essential ingredients that connect information processing, adaptation, and memory in biological systems

Variação do preço e consumo de peixes no Mercado Público de Porto Alegre

A demanda mundial por pescado é crescente e, embora a obtenção extrativa de organismos aquáticos tenha estabilizado por volta dos anos de 1990, a aquicultura praticamente dobrou na última década, de acordo com dados da FAO (Food and Agriculture Organization). O consumo de pescado traz uma série de benefícios à saúde, ele possui proteína de alto valor biológico e é rico em ácidos graxos poli-insaturados, fundamentais ao equilíbrio das dietas modernas, uma vez que os processos de industrialização utilizam altos teores de óleo refinado. No cenário mundial, a pesca e a aquicultura forneceram cerca de 148 milhões de toneladas de peixes em 2010, sendo 128 milhões destas destinadas ao consumo humano. A produção de pescado brasileira vem contribuindo para o agronegócio, visto que em 2011 a exportação nacional representou US$ 271 milhões. Com base nesse contexto, o presente trabalho tem como principal objetivo verificar se ocorre relação entre a disponibilidade das espécies de peixe no Mercado Público de Porto Alegre, Rio Grande do Sul (RS), e a variação de seus preços ao longo de 13 meses. Tais dados podem possibilitar maior planejamento de compra aos consumidores

Replacement of pork meal by plant protein sources in Hungarian carp diets

O objetivo deste trabalho foi avaliar o crescimento e a qualidade de carcaça de carpa-húngara alimentada com dietas em que houve substituição da farinha de carne suína por farelos de soja e canola, bem como determinar parâmetros bioquímicos do metabolismo dos peixes e a qualidade sensorial do filé. Cada um dos farelos contribuiu com 50% da proteína na mistura. Cinco dietas foram avaliadas, com níveis de substituição (0, 25, 50, 75 e 100%) da proteína da farinha de carne suína pela mistura das fontes vegetais. A inclusão de fontes proteicas vegetais nas dietas reduziu o crescimento, a deposição de gordura corporal e no filé, e o colesterol total dos peixes. A cor e o sabor dos filés não foram afetados pela inclusão das fontes proteicas vegetais. A dieta à base de farinha de carne suína é mais eficiente para o crescimento da carpa-húngara, e proporciona maior deposição de proteína no peixe inteiro e no filé.The objective of this work was to evaluate growth and carcass composition of Hungarian carp fed with diets in which pork meat meal was replaced by a combination of canola and soybean meals, as well as to determine fish metabolism biochemical parameters and the sensorial quality of the fillet. Each plant meal contributed with 50% of the dietary protein of the mixture. Five diets were tested, with replacement levels of 0, 25, 50, 75 and 100% of pork meal by plant protein sources. The inclusion of the plant-protein meal in the diet results in lower overall growth, lower body and fillet lipid deposition and lower total cholesterol of the fish. Color and flavor of the fillets were not affected by inclusion of plant protein sources. A pork meat meal based diet is more efficient for Hungarian carp growth, and provides higher whole fish and fillet protein deposition

Tephrochronology in faulted Middle Pleistocene tephra layer in the Val dAgri area (Southern Italy)

The High Agri River Valley is a Quaternary Basin located along the hinge of the Southern Apennines fold-andthrust belt. The inner margin of the orogen has been affected by intense transtensional and normal faulting, which accompanied vigorous volcanism during the Quaternary. Marker tephra layers are distributed across the whole of Southern Italy and provide a powerful tool to constrain both the size of eruptions and the regional activity of extensional faults controlling basin evolution. Paleoseismological trenching within the Monti della Maddalena range, that borders the Agri River Valley to the south-west, has exposed a faulted stratigraphic sequence and recovered a 10 cm thick tephra layer involved in deformation. This is the first tephra horizon recognized in the high Agri Valley, which, based on the stratigraphic study of the trench, lies in a primary position. 40Ar/39Ar dating constrain its age to 266 ka and provide an important marker for the Middle Pleistocene tephrochronology of the region. Together with dating, geochemical analysis suggests a possible volcanic source in the Campanian region

Virtual Reality, 360⁰ Video, and Journalism Studies: Conceptual Approaches to Immersive Technologies

A growing number of newsrooms are experimenting with Virtual Reality (VR) and other immersive storytelling techniques, typically supported by technology companies that see journalism as a potential vehicle for taking VR mainstream. The resulting pieces have been wide-ranging in topic, style, and scope, but all introduce new complexities to journalistic norms and practices. To date, however, journalism studies scholars have conducted relatively little research into these immersive technologies. This essay proposes three conceptual approaches to examining VR journalism: Actor-Network Theory, normative theory, and a sociological perspective on journalistic work

Viability of zebrafish (Danio rerio) ovarian follicles after vitrification in a metal container.

Cryopreservation of ovarian tissue has been studied for female germline preservation of farm animals and endangered mammalian species. However, there are relatively few reports on cryopreservation of fish ovarian tissue and especially using vitrification approach. Previous studies of our group has shown that the use of a metal container for the cryopreservation of bovine ovarian fragments results in good primordial and primary follicle morphological integrity after vitrification. The aim of this study was to assess the viability and in vitro development of zebrafish follicles after vitrification of fragmented or whole ovaries using the same metal container. In Experiment 1, we tested the follicular viability of five developmental stages following vitrification in four vitrification solutions using fluorescein diacetate and propidium iodide fluorescent probes. These results showed that the highest viability rates were obtained with immature follicles (Stage I) and VS1 (1.5 M methanol + 4.5 M propylene glycol). In Experiment 2, we used VS1 to vitrify different types of ovarian tissue (fragments or whole ovaries) in two different carriers (plastic cryotube or metal container). In this experiment, Stage I follicle survival was assessed following vitrification by vital staining after 24 h in vitro culture. Follicular morphology was analyzed by light microscopy after vitrification. Data showed that the immature follicles morphology was well preserved after cryopreservation. Follicular survival rate was higher (P < 0.05) in vitrified fragments, when compared to whole ovaries. There were no significant differences in follicular survival and growth when the two vitrification devices were compared

Stocking density and feeding rate of South American catfish reared in net cages

O objetivo deste trabalho foi avaliar o efeito de diferentes densidades de estocagem e frequências alimentares sobre a resposta zootécnica e metabólica, e sobre a composição de peixe inteiro e de filé de juvenis de jundiá (Rhamdia quelen) cultivados em tanques‑rede durante 60 dias. Foram utilizados 1.200 juvenis de jundiá (57,48±3,34 g e 17,86±0,36 cm). Os peixes foram distribuídos em delineamento inteiramente casualizado, em arranjo fatorial 2×2, à densidade de 50 e 150 peixes m‑3 e frequência alimentar de uma ou duas vezes ao dia. Tanto as densidades de estocagem quanto o manejo alimentar não influenciaram o desempenho nem os parâmetros metabólicos. No entanto, a interação entre a menor densidade e a maior frequência alimentarresultou em menor teor lipídico nos filés. Como ambos os fatores testados não interferiram no desempenho zootécnico, pode-se sugerir como melhor densidade a de 150 peixes m‑³, com frequência de arraçoamento de uma vez ao dia.The objective of this work was to evaluate the effect of different stocking densities and feeding frequencies on the zootechnical and metabolic response and on the whole fish and fillet composition of juvenile South American catfish (Rhamdia quelen) cultured in net cages for 60 days. One thousand and two hundred juvenile catfish (57,48±3,34 g and 17,86±0,36 cm) were used. Fish were distributed in a completely randomized design, with a 2×2 factorial arrangement, at 50 and 150 fish m‑3 and feeding frequency once or twice a day. Both stocking density and feeding influenced neither the performance, nor the metabolic parameters. However, the interaction between the lowest density and the highest feeding frequency resulted in the lowest lipid content in the fillets. As both tested factors did not affect the growth performance, 150 fish m‑3 can be suggested as the best density together with a once‑a‑day feeding frequency

Hundreds of variants clustered in genomic loci and biological pathways affect human height

Most common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype. Genome-wide association (GWA) studies have identified more than 600 variants associated with human traits, but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait. The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P = 0.016) and that underlie skeletal growth defects (P < 0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Our data explain approximately 10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to approximately 16% of phenotypic variation (approximately 20% of heritable variation). Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways.

Risk of hyperkalemia in patients with moderate chronic kidney disease initiating angiotensin converting enzyme inhibitors or angiotensin receptor blockers : a randomized study

Background: Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers are renoprotective but both may increase serum potassium concentrations in patients with chronic kidney disease (CKD). The proportion of affected patients, the optimum follow-up period and whether there are differences between drugs in the development of this complication remain to be scertained. Methods: In a randomized, double-blind, phase IV, controlled, crossover study we recruited 30 patients with stage 3 CKD under restrictive eligibility criteria and strict dietary control. With the exception of withdrawals, each patient was treated with olmesartan and enalapril separately for 3 months each, with a 1-week wash-out period between treatments. Patients were clinically assessed on 10 occasions via measurements of serum and urine samples. We used the Cochran-Mantel-Haenszel statistics for comparison of categorical data between groups. Comparisons were also made using independent two-sample t-tests and Welch's t-test. Analysis of variance (ANOVA) was performed when necessary. We used either a Mann-Whitney or Kruskal-Wallis test if the distribution was not normal or the variance not homogeneous. Results: Enalapril and olmesartan increased serum potassium levels similarly (0.3 mmol/L and 0.24 mmol/L respectively). The percentage of patients presenting hyperkalemia higher than 5 mmol/L did not differ between treatments: 37% for olmesartan and 40% for enalapril. The mean e-GFR ranged 46.3 to 48.59 ml/mint/1.73 m2 in those treated with olmesartan and 46.8 to 48.3 ml/mint/1.73 m2 in those with enalapril and remained unchanged at the end of the study. The decreases in microalbuminuria were also similar (23% in olmesartan and 29% in enalapril patients) in the 4 weeks time point. The percentage of patients presenting hyperkalemia, even after a two month period, did not differ between treatments. There were no appreciable changes in sodium and potassium urinary excretion. Conclusions: Disturbances in potassium balance upon treatment with either olmesartan or enalapril are frequent and without differences between groups. The follow-up of these patients should include control of potassium levels, at least after the first week and the first and second month after initiating treatment