368 research outputs found
Evolution signatures in genome network properties
Genomes maybe organized as networks where protein-protein association plays the role of network links. The resulting networks are far from being random and their topological properties are a consequence of the underlying mechanisms for genome evolution. Considering data on protein-protein association networks from STRING database, we present experimental evidence that degree distribution is not scale free, presenting an increased probability for high degree nodes. We also show that the degree distribution approaches a scale invariant state as the number of genes in the network increases, although real genomes still present finite size effects. Based on the experimental evidence unveiled by these data analyses, we propose a simulation model for genome evolution, where genes in a network are either acquired de novo using a preferential attachment rule, or duplicated, with a duplication probability that linearly grows with gene degree and decreases with its clustering coefficient. The results show that topological distributions are better described than in previous genome evolution models. This model correctly predicts that, in order to produce protein-protein association networks with number of links and number of nodes in the observed range, it is necessary 90% of gene duplication and 10% of de novo gene acquisition. If this scenario is true, it implies a universal mechanism for genome evolution
Desempenho acad?mico de alunos de 9? ano na Geometria Espacial: impacto de vari?veis pessoal e de contexto
This article presents and discusses results from a study investigating the quality of Spatial Geometry academic performance of 9th grade students when they are about to be exposed to more complex concepts, geometric solids, and related problems in curricular learning experiences. Participants were Portuguese public school students. We also collected information about previous mathematics grades and mother?s schooling. A geometry test, a causal attribution to a school achievement test, and two reasoning tests ? spatial and mechanical ? were applied, and all collected data was statistically analysed and interpreted. To address the different nature of variables, we conducted a hierarchical linear regression. Results suggest that nearly 41% of variance on Spatial Geometry academic performance can be explained by the personal and contextual variables studied. The recommendation to schoolteachers involves designing learning experiences that engage students in spatial reasoning and high-order thinking skills.AF10-A514-BE72 | Luciana Pereira de BritoN/
The importance of cultural aspects in impact assessment and project: developmentreflections from a case study of a hydroelectric dam in Brazil
Failure to consider the cultural and social factors of projects can lead to situations where mitigation does not effectively address the impacts they were intended to alleviate, and can even create other impacts. We critically analyse the processes of designing and implementing a social and environmental compensation program for the Lajeado Hydroelectric Dam in the Amazon region of central-northern Brazil. This mitigation program caused a wide range of social and environmental impacts on the Xerente Indigenous people, such as intra-group conflict, and changes in agricultural practices and food regime. Based on qualitative fieldwork and an extensive document analysis, we present a contextualization of the region, the project, the Xerente people, and their cosmological understandings. We consider the perspectives of a broad range of stakeholders about the compensation program and its outcomes, and demonstrate how traditional cultural practices and values played a role in the unfolding of the program. Better comprehension of sociocultural aspects through the use of ethnography, ongoing consultation, and meaningful community participation in the planning and implementation of mitigation measures are recommended.</p
Effect of tetramethylammonium hydroxide on nucleation, surfacemodification and growth ofmagnetic nanoparticles.
Nanoparticles of magnetite (Fe3O4) were obtained by reacting ferric chloride with sodium sulphite, through the reductionprecipitation
method. The effects of adding tetramethylammonium hydroxide (TMAOH) during or after the precipitation of the
iron oxide were studied in an attempt to obtain well-dispersed magnetite nanoparticles. Accordingly, the following experimental
conditions were tested: (i) precipitation in absence of TMAOH (sample Mt), (ii) the same as (i) after peptizing with TMAOH
(Mt1), (iii) TMAOH added to the reaction mixture during the precipitation of magnetite (Mt2). Analyses with transmission
electron microscopy (TEM), X-ray diffraction, M?ossbauer spectroscopy, attenuated total reflectance Fourier transform infrared
spectroscopy (ATR-FTIR), zeta potential, and magnetization measurements up to 2.5 T revealed that magnetite was normally
formed also in the medium containing TMAOH. The degree of particles agglomeration was monitored with laser diffraction
and technique and inspection of TEM images. The relative contributions of N?eel and Brownian relaxations on the magnetic heat
dissipation were studied by investigating the ability of suspensions of these magnetite nanoparticles to release heat in aqueous
and in hydrogel media. Based on ATR-FTIR and zeta potential data, it is suggested that the surfaces of the synthesized magnetite
particles treated with TMAOH become coated with (CH3)4N+ cations
Bronchial asthma in children: Clinical and epidemiologic approach in different Portuguese speaking countries
Precision technologies to address dairy cattle welfare: focus on lameness, mastitis and body condition
Specific animal-based indicators that can be used to predict animal welfare have been the
core of protocols for assessing the welfare of farm animals, such as those produced by the Welfare
Quality project. At the same time, the contribution of technological tools for the accurate and realtime assessment of farm animal welfare is also evident. The solutions based on technological tools
fit into the precision livestock farming (PLF) concept, which has improved productivity, economic
sustainability, and animal welfare in dairy farms. PLF has been adopted recently; nevertheless, the
need for technological support on farms is getting more and more attention and has translated into
significant scientific contributions in various fields of the dairy industry, but with an emphasis on
the health and welfare of the cows. This review aims to present the recent advances of PLF in dairy
cow welfare, particularly in the assessment of lameness, mastitis, and body condition, which are
among the most relevant animal-based indications for the welfare of cows. Finally, a discussion is
presented on the possibility of integrating the information obtained by PLF into a welfare
assessment framework.FE1B-06B2-126F | Jos? Pedro Pinto de Ara?joN/
Nuclear WRAP53 promotes neuronal survival and functional recovery after stroke
Failure of neurons to efficiently repair DNA double-strand breaks (DSBs) contributes to cerebral damage after stroke. However, the molecular machinery that regulates DNA repair in this neurological disorder is unknown. Here, we found that DSBs in oxygen/glucose-deprived (OGD) neurons spatiotemporally correlated with the up-regulation of WRAP53 (WD40-encoding p53-antisense RNA), which translocated to the nucleus to activate the DSB repair response. Mechanistically, OGD triggered a burst in reactive oxygen species that induced both DSBs and translocation of WRAP53 to the nucleus to promote DNA repair, a pathway that was confirmed in an in vivo mouse model of stroke. Noticeably, nuclear translocation of WRAP53 occurred faster in OGD neurons expressing the Wrap53 human nonsynonymous single-nucleotide polymorphism (SNP) rs2287499 (c.202C>G). Patients carrying this SNP showed less infarct volume and better functional outcome after stroke. These results indicate that WRAP53 fosters DNA repair and neuronal survival to promote functional recovery after stroke
Carbon stock determination in teak ( Tectona grandis l. F. ) at different ages
The objective of this study was to evaluate the quantity of carbon in
teak ( Tectona grandis L.f.), with 0.5; 1.5; 2.5; 3.5 and 5.5 years
of age, during one year. The teak evaluated belonged to the BRASTECA
AGROFLORESTAL LTDA company, located in the municipality of Santo
Ant\uf4nio of Leverger, Mato Grosso, Brazil. The carbon stock for
each age was assessed every 90 days by determining the amount of litter
dry mass, organic carbon proportion in the soil, root density in the
soil and the volume of the staff and crown in the three teak trees
randomly selected for harvest. The assessment of the plant size, as
height, diameter at chest height and crown projection, was carried out
with twenty preserved plants at each age. The dry mass of the roots was
determined from the relation between the soil volume and the density of
roots of the three plants per age, by making four perforations per
plant, with six samples for each, up to 0.90 m of depth. The carbon
proportion in the soil and in the litter was obtained by age at each
collection through laboratory analysis. The average carbon found per
hectare was 122.5 t of C at 0.5 years; 104.3 t of C at 1.5 years; 180.8
t of C at 2.5 years; 303.1 t of C at 3.5 years and 322.3 t of C at 5.5
years, considering the numbers of plants per hectare at the different
ages. Afterward, the average distribution of carbon per system
component was found to be 90.8% in the soil, 5.04% to the aerial part,
3.04% in the roots and 1.21% in the litter.O objetivo deste trabalho foi avaliar a quantidade de carbono em
cultivo de Teca ( Tectona grandis L.f.), com 0,5; 1,5; 2,5; 3,5 e 5,5
anos de idade ao longo de um ano pertencentes \ue0 empresa BrasTeca
Agroflorestal Ltda, localizada no munic\uedpio de Santo Ant\uf4nio
do Leverger, MT. O estoque de carbono em cada idade foi obtido a cada
90 dias, por meio da determina\ue7\ue3o da quantidade de massa seca
da serapilheira acumulada, do teor de carbono org\ue2nico no perfil
do solo, da densidade de ra\uedzes no solo e da mensura\ue7\ue3o
do volume do fuste e da copa em tr\ueas plantas escolhidas ao acaso.
A avalia\ue7\ue3o do tamanho das plantas, em altura total,
di\ue2metro \ue0 altura do peito e proje\ue7\ue3o da copa, foi
realizada em vinte plantas preservadas em cada idade. A
quantifica\ue7\ue3o do carbono da parte a\ue9rea foi realizada
por meio do corte de tr\ueas plantas em cada idade, obtendo a massa
fresca total por componente. Para determinar a massa seca de
ra\uedzes, utilizou-se a rela\ue7\ue3o entre volume de solo e
densidade de raiz de tr\ueas plantas por idade, sendo realizadas
quatro perfura\ue7\uf5es por planta, com seis subamostras cada,
at\ue9 a profundidade de 0,90 m. O teor de carbono no solo e na
serapilheira acumulada, a cada coleta e por idade, foi obtido ap\uf3s
an\ue1lise em laborat\uf3rio. A quantidade m\ue9dia de carbono
encontrada por hectare foi de 122,5 t de C para 0,5 ano, de 104,3 t de
C para 1,5 ano, de 180,8 t de C para 2,5 anos, de 303,1 t de C para 3,5
anos e de 322,3 t de C para 5,5 anos, considerando o n\ufamero de
plantas por hectare nas diferentes idades. Verificou-se que a
distribui\ue7\ue3o m\ue9dia de carbono por componente no sistema
foi de 90,8% no solo, 5,04% para a parte a\ue9rea, 3,04% nas
ra\uedzes e de 1,21% na serapilheira acumulada
Analysis of the Use of Cylindrospermopsin and/or Microcystin-Contaminated Water in the Growth, Mineral Content, and Contamination of Spinacia oleracea and Lactuca sativa
Cyanobacteria and cyanotoxins constitute a serious environmental and human health problem. Moreover, concerns are raised with the use of contaminated water in agriculture and vegetable production as this can lead to food contamination and human exposure to toxins as well as impairment in crop development and productivity. The objective of this work was to assess the susceptibility of two green vegetables, spinach and lettuce, to the cyanotoxins microcystin (MC) and cylindrospermopsin (CYN), individually and in mixture. The study consisted of growing both vegetables in hydroponics, under controlled conditions, for 21 days in nutrient medium doped with MC or CYN at 10 μg/L and 50 μg/L, or CYN/MC mixture at 5 + 5 μg/L and 25 + 25 μg/L. Extracts from M. aeruginosa and C. ovalisporum were used as sources of toxins. The study revealed growth inhibition of the aerial part (Leaves) in both species when treated with 50µg/L of MC, CYN and CYN/MC mixture. MC showed to be more harmful to plant growth than CYN. Moreover spinach leaves growth was inhibited by both 5 + 5 and 25 + 25 µg/L CYN/MC mixtures, whereas lettuce leaves growth was inhibited only by 25 + 25 µg/L CYN/MC mixture. Overall, growth data evidence increased sensitivity of spinach to cyanotoxins in comparison to lettuce. On the other hand, plants exposed to CYN/MC mixture showed differential accumulation of CYN and MC. In addition, CYN, but not MC, was translocated from the roots to the leaves. CYN and MC affected the levels of minerals particularly in plant roots. The elements most affected were Ca, K and Mg. However, in leaves K was the mineral that was affected by exposure to cyanotoxins.info:eu-repo/semantics/publishedVersio
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