Correlações entre caracteres morfológicos, físicos e químicos de híbridos de Brachiaria humidicola.

No melhoramento de plantas forrageiras é de grande importância a seleção de genótipos com alta qualidade e valor nutritivo, para isso faz-se necessário o entendimento das relações genéticas entre os caracteres. O objetivo foi determinar as correlações genéticas e fenotípicas entre os caracteres físicos, morfológicos e químicos avaliados em 50 progênies de B. humidicola no estádio maduro. A força de cisalhamento foi determinada pelo aparelho do tipo ?Warner-Brazler?, a qual foi padronizada pelo peso, largura e comprimento das folhas. Houve diferença significativa (P < 0,01) para todos os caracteres avaliados. A digestibilidade in vitro da matéria orgânica apresentou correlações genéticas nulas com os caracteres físicos, enquanto com os constituintes da parede celular as correlações foram altas e negativas (-0,9 (FDN), -0,72 (FDA), -0,72 (lignina) e -0,7 (celulose)). A força de cisalhamento apresentou moderada correlação genética com a FDA, lignina e celulose (r = 0,52, 0,36 e 0,55, respectivamente), porém quando essa foi padronizada com a largura e a densidade linear houve um aumento das correlações com o FD

Effect of Season and Year of Evaluation in the Selection of \u3cem\u3eBrachiaria humidicola\u3c/em\u3e Hybrids

Brachiaria humidicola is well adapted to infertile and acid soils with poor drainage or temporary flooding (Keller-Grein et al. 1996). It is widely used in Brazil in wetlands and areas of marginal land characterised by waterlogged soils. During the evaluation stages of the breeding program of this species, genotypes are generally tested using consecutive cuts within different seasons for at least 2 years. The ‘Cerrado’ region, where most animal production takes place in Brazil, has 2 well defined seasons: spring-summer with warm weather and rain; and autumn-winter with cooler, dry weather. Thus, owing to environmental variation, especially related to climate, it is important to investigate the main effects of environmental factors (years and seasons), as well as interactions between genotypes and environmental factors in order to have greater confidence in the selection of superior hybrids of B. humidicola on the basis of agronomic and nutritional traits

Homework, self-regulated learning and math achievement

Las tareas para casa es una estrategia instruccional de carácter universal. La literatura se ha centrado en el impacto del tiempo utilizado en las tareas en el rendimiento; no obstante investigaciones recientes sugieren la necesidad de estudiar otras variables de carácter más procesual. Centrados en el área de las matemáticas se analiza en alumnos portugueses de Primaria (10 y 11 años) el poder predictivo de variables motivacionales (ej., autoeficacia y autorregulación del aprendizaje) en el rendimiento escolar en esta asignatura. Posteriormente, se estudia el poder predictivo de variables de las tareas para casa (ej., esfuerzo, instrumentalidad percibida de las tareas) en las variables motivacionales mencionadas. Los datos indican que el rendimiento en matemáticas se explica por las variables motivacionales pero también que éstas son explicadas por variables de las tareas de casa, subrayando su importancia en la promoción del éxito escolar. Finalmente, se exponen y discuten las implicaciones educativas.Homework is a well known teaching strategy in schools all over the world. Although most studies privilege time spent on homework as a measure to evaluate homework effects on achievement new literature approach perspectives suggest the need to study other variables involved in the homework process. Focusing on Math’s domain, the present paper analyses the impact of motivational variables (e.g., self-efficacy and self-regulated learning) on Portuguese elementary school students’ (aged 10 and 11) achievement. The impact of some homework variables (e.g., effort on homework, perceived utility of homework tasks) on the taken motivational variables is also addressed and analyzed. Data confirm that students’ Math achievement is influenced by the motivational variables taken in the study and that these, on their turn, are influenced by the homework variables, thus stressing their important role in the promotion of students’ school success. Teaching implications are also discussed

Evaluating early selection in perennial tropical forages.

Perennial grass hybrids of Urochloa are evaluated for at least two years during the screening stage trials (SS) and advanced trials (AD) in breeding programs, an expensive and time-consuming process. In this study, we aimed to evaluate the potential for early selection of cultivars in this breeding scheme. We used multiple measurements of agronomic and nutritive value traits of Urochloa humidicola and Urochloa decumbens in the SS, and Urochloa ssp. in the AD. Repeatability coefficient, genetic correlation, selection efficiency (SE), and Spearman correlations were estimated. The results indicated that reliable early selection could be applied, decreasing the evaluation period to one year and a half for SS, and to one year for AD. These results were confirmed by high genetic and rank correlations, and overall SE above 50%. This proposed change in the breeding scheme could save considerable time, labor, and resources and accelerate the release of improved cultivars

Irreplaceable socioeconomic value of wild meat extraction to local food security in rural Amazonia

Wild vertebrates play a decisive role in the subsistence economy of human populations worldwide. The food security value of wild-meat extracted from natural ecosystems remains poorly quantified. Here, we provide an economic valuation of the nutritional and monetary benefits of year-round wild-meat hunting across a large trinational region of southwestern Amazonia using data from indigenous and non-indigenous settlements from 30 sites. We then build scenarios to explore whether three ubiquitous sources of regional-scale household income (i.e. wage labour, horticultural revenues from manioc flour production and the harvest of Brazil-nuts) could match the purchase costs of alternative meat demand to meet domestic consumption of animal protein should game stocks collapse for any reason. We also considered a fourth valuation scenario in terms of game meat substitution with bovine beef. We conservatively estimate a total annual consumption of ~1431.8 tons of undressed animal carcasses, equivalent to a mean per-capita meat consumption of 54.75 kg person−1 yr−1, or ~10.9 kg of animal protein person−1 yr−1. This overall consumption of terrestrial wildlife meat provides US$7.875 million yr−1 across the study region. However, household income levels were too low to enable transitions into domestic livestock consumption indicating low adaptation capacity to alternative animal protein; replacement purchases of domestic meat would amount to 90$2.658 million yr−1 and the conversion of 4310 ha of Amazonian forests into pasture. Our results emphasize the extraordinarily valuable and irreplaceable role of wild meat in the food security of tropical forest dwellers. Proposing consumption of alternative sources of animal protein for monetarily deprived forest dwellers is clearly an unrealistic, if not environmentally-damaging, strategy. Conservation scientists, wildlife biologists and policy makers should therefore prioritize adding value to standing forests by managing sustainable wild-meat offtake from natural ecosystems

Wild meat consumption in tropical forests spares a significant carbon footprint from the livestock production sector

Whether sustainable or not, wild meat consumption is a reality for millions of tropical forest dwellers. Yet estimates of spared greenhouse gas (GHG) emissions from consuming wild meat, rather than protein from the livestock sector, have not been quantified. We show that a mean per capita wild meat consumption of 41.7 kg yr −1 for a population of ~ 150,000 residents at 49 Amazonian and Afrotropical forest sites can spare ~ 71 MtCO 2-eq annually under a bovine beef substitution scenario, but only ~ 3 MtCO 2-eq yr −1 if this demand is replaced by poultry. Wild meat offtake by these communities could generate US$3M or US$185K in carbon credit revenues under an optimistic scenario (full compliance with the Paris Agreement by 2030; based on a carbon price of US$50/tCO 2-eq) and US$1M or US$77K under a conservative scenario (conservative carbon price of US$20.81/tCO 2-eq), representing considerable incentives for forest conservation and potential revenues for local communities. However, the wild animal protein consumption of ~ 43% of all consumers in our sample was below the annual minimum per capita rate required to prevent human malnutrition. We argue that managing wild meat consumption can serve the interests of climate change mitigation efforts in REDD + accords through avoided GHG emissions from the livestock sector, but this requires wildlife management that can be defined as verifiably sustainable

Extending the ecological distribution of Desmonostoc genus: proposal of Desmonostoc salinum sp. nov., a novel Cyanobacteria from a saline–alkaline lake

Cyanobacteria is an ancient phylum of oxygenic photosynthetic microorganisms found in almost all environments of Earth. In recent years, the taxonomic placement of some cyanobacterial strains, including those belonging to the genus Nostoc sensu lato, have been reevaluated by means of a polyphasic approach. Thus, 16S rRNA gene phylogeny and 16S–23S internal transcribed spacer (ITS) secondary structures coupled with morphological, ecological and physiological data are considered powerful tools for a better taxonomic and systematics resolution, leading to the description of novel genera and species. Additionally, underexplored and harsh environments, such as saline–alkaline lakes, have received special attention given they can be a source of novel cyanobacterial taxa. Here, a filamentous heterocytous strain, Nostocaceae CCM-UFV059, isolated from Laguna Amarga, Chile, was characterized applying the polyphasic approach; its fatty acid profile and physiological responses to salt (NaCl) were also determined. Morphologically, this strain was related to morphotypes of the Nostoc sensu lato group, being phylogenetically placed into the typical cluster of the genus Desmonostoc. CCM-UFV059 showed identity of the 16S rRNA gene as well as 16S–23S secondary structures that did not match those from known described species of the genus Desmonostoc, as well as distinct ecological and physiological traits. Taken together, these data allowed the description of the first strain of a member of the genus Desmonostoc from a saline–alkaline lake, named Desmonostoc salinum sp. nov., under the provisions of the International Code of Nomenclature for algae, fungi and plants. This finding extends the ecological coverage of the genus Desmonostoc, contributing to a better understanding of cyanobacterial diversity and systematics

An Approach to an Inhibition Electronic Tongue to Detect On-Line Organophosphorus Insecticides Using a Computer Controlled Multi-Commuted Flow System

An approach to an inhibition bioelectronic tongue is presented. The work is focused on development of an automated flow system to carry out experimental assays, a custom potentiostat to measure the response from an enzymatic biosensor, and an inhibition protocol which allows on-line detections. A Multi-commuted Flow Analysis system (MCFA) was selected and developed to carry out assays with an improved inhibition method to detect the insecticides chlorpyrifos oxon (CPO), chlorfenvinfos (CFV) and azinphos methyl-oxon (AZMO). The system manifold comprised a peristaltic pump, a set of seven electronic valves controlled by a personal computer electronic interface and software based on LabView® to control the sample dilutions into the cell. The inhibition method consists in the injection of the insecticide when the enzyme activity has reached the plateau of the current; with this method the incubation time is avoided. A potentiostat was developed to measure the response from the enzymatic biosensor. Low limits of detection of 10 nM for CPO, CFV, and AZMO were achieved

Fortnightly changes in water transport direction across the mouth of a narrow estuary

This research investigates the dynamics of the axial tidal flow and residual circulation at the lower Guadiana Estuary, south Portugal, a narrow mesotidal estuary with low freshwater inputs. Current data were collected near the deepest part of the channel for 21 months and across the channel during two (spring and neap) tidal cycles. Results indicate that at the deep channel, depth-averaged currents are stronger and longer during the ebb at spring and during the flood at neap, resulting in opposite water transport directions at a fortnightly time scale. The net water transport across the entire channel is up-estuary at spring and down-estuary at neap, i.e., opposite to the one at the deep channel. At spring tide, when the estuary is considered to be well mixed, the observed pattern of circulation (outflow in the deep channel, inflow over the shoals) results from the combination of the Stokes transport and compensating return flow, which varies laterally with the bathymetry. At neap tide (in particular for those of lowest amplitude each month), inflows at the deep channel are consistently associated with the development of gravitational circulation. Comparisons with previous studies suggest that the baroclinic pressure gradient (rather than internal tidal asymmetries) is the main driver of the residual water transport. Our observations also indicate that the flushing out of the water accumulated up-estuary (at spring) may also produce strong unidirectional barotropic outflow across the entire channel around neap tide.info:eu-repo/semantics/publishedVersio