84 research outputs found
Systemic release of volatiles by Brassica oleracea var. acephala induced by Pieris brassicae predation.
Pieris brassicae is a specialist on crucifers and its interactions with some of its host plants have
been increasingly studied given their importance in pest management, chemical ecology and
entomology. Plants are known to respond to insect attack by releasing volatiles that can either
warn neighbour plants to the presence of a predator or attract insect parasitoids, thus reducing
the attack efficiency. The influence of P. brassicae feeding on Brassica oleracea L. var. acephala
(kale) was investigated, namely, its effect in the volatiles released by the plant through time.
Substantial differences, mainly quantitative, were found between the volatiles composition of B.
oleracea var. acephala before the attack and after insect feeding. More than 40 compounds were
found, between terpenes (monoterpenes and sesquiterpenes) and lipoxygenase pathway byproducts
(alcohols and aldehydes), ketones, norisoprenoids, among others. After insect attack,
monoterpenes like limonene, eucalyptol, camphor and caryophyllene increased noticeably.
These compounds have been regarded as markers in local tissue responses and in this study an
increase in their concentration was detected at 1 and 4 hours after feeding, with subsequent
reduction after 8 hours. Menthol, menthone, phenol and sabinene were found only in the time
following the attack. A considerable increase in hexenyl acetate, a well known semiochemical,
was also found, with this compound being the major peak in all experiments, rising with time.
These findings provide further knowledge of the ecological interactions between these two
species and, given the chemical diversity of these matrices, they may constitute a good source
of health promoting compounds.Fundação para a Ciência e Tecnologia for financial support (PTDC/AGRAAM/
64150/2006). F. Fernandes (SFRH/BD/37963/2007
Metabolic fate of dietary volatile compounds in Pieris brassicae
In this work, the evolution of the qualitative and quantitative profile of the volatile fraction of Pieris brassicae
after feeding on Brassica oleracea var. acephala (kale) was monitored through time. HS-SPME/GC-MS was
applied to both the host plant and the living insect and its excrements. A total of seventy seven compounds
(lipoxygenase pathway by-products, nitrogen compounds, norisoprenoids, sulphur compounds, terpenes,
among others) were identified. Thirty eight compounds were identified in insect after 2 h of starvation and
forty eight compounds in excrements. Qualitative and quantitative changes were detected along time.
Dimethyldisulfide, dimethyltrisulfide, limonene and eugenol were major compounds for all analysed times in
both matrices, being limonene an important compound in insect after starvation. The accumulation by
P. brassicae of some compounds, such as limonene, was verified, suggesting a mechanism by which the insect
can take benefit from bioactive constituents from the diet. Along with accumulation, complete excretion of
some compounds, including nitrogen bearing compounds, by-products of glucosinolates was detected. These
results reflect one of the strategies used to overcome plant barriers, namely detoxification of toxic
compounds. The findings contribute to the knowledge of the metabolization of the volatile compounds in
insects and contribute to the body of knowledge of this ecologic system.FC
Extensive Sheep and Goat Production: The Role of Novel Technologies towards Sustainability and Animal Welfare
ReviewSheep and goat extensive production systems are very important in the context of global
food security and the use of rangelands that have no alternative agricultural use. In such systems,
there are enormous challenges to address. These include, for instance, classical production issues, such
as nutrition or reproduction, as well as carbon-efficient systems within the climate-change context.
An adequate response to these issues is determinant to economic and environmental sustainability.
The answers to such problems need to combine efficiently not only the classical production aspects,
but also the increasingly important health, welfare, and environmental aspects in an integrated fashion. The purpose of the study was to review the application of technological developments,
in addition to remote-sensing in tandem with other state-of-the-art techniques that could be used
within the framework of extensive production systems of sheep and goats and their impact on
nutrition, production, and ultimately, the welfare of these species. In addition to precision livestock
farming (PLF), these include other relevant technologies, namely omics and other areas of relevance
in small-ruminant extensive production: heat stress, colostrum intake, passive immunity, newborn
survival, biomarkers of metabolic disease diagnosis, and parasite resistance breeding. This work
shows the substantial, dynamic nature of the scientific community to contribute to solutions that
make extensive production systems of sheep and goats more sustainable, efficient, and aligned with
current concerns with the environment and welfareinfo:eu-repo/semantics/publishedVersio
Prototipo funcional de un sistema de clasificación para las cerezas de café castillo, en función de su etapa de maduración
Trabajo de InvestigaciónEn el siguiente proyecto de grado se desarrolla un prototipo funcional para la clasificación automatizada de café castillo en función de su etapa de maduración, el cual consta de un sensor de color RGB, una banda transportadora, un servomotor para el desvió de las cerezas de café y el microcontrolador atmega328p. Inicialmente se realiza una búsqueda de las tecnologías que se emplean para este proceso, posterior a esto se selecciona los dispositivos que se usaran, ya con esto, se hace el modelado 3D del prototipo en el software Autodesk Inventor, se simula el sistema en Proteus y se diseña el circuito impreso (PCB) en EasyEDA, después de esto se realiza la implementación del prototipo para finalmente hacer las pruebas de validación.INTRODUCCIÓN
1. GENERALIDADES
2. METODOLOGÍA
3. DESCRIPCIÓN ECONÓMICA DEL PROYECTO
4. CONCLUSIONES
5. RECOMENDACIONES Y TRABAJOS FUTUROS
BIBLIOGRAFÍA
ANEXOSPregradoIngeniero Electrónic
Re-creation of site-specific multi-directional waves with non-collinear current
Site-specific wave data can be used to improve the realism of tank test conditions and resulting outputs. If this data is recorded in the presence of a current, then the combined conditions must be re-created to ensure wave power, wavelength and steepness are correctly represented in a tank. In this paper we explore the impacts of currents on the wave field and demonstrate a simple, effective methodology for re-creating combined wave-current scenarios. Regular waves, a parametric unidirectional spectrum, and a complex site-specific directional sea state were re-created with current velocities representing 0.25, 0.5, and 1.0 m/s full scale. Waves were generated at a number of angles relative to the current, providing observations of both collinear and non-collinear wave-current interactions. Wave amplitudes transformed by the current were measured and corrected linearly, ensuring desired frequency and wavenumber spectra in the presence of current were obtained. This empirical method proved effective after a single iteration. Frequency spectra were within 3% of desired and wave heights normally within 1%. The generation-measurement-correction procedure presented enables effective re-creation of complex wave-current scenarios. This capability will increase the realism of tank testing, and help de-risk devices prior to deployment at sea
Doença de depósito lisossomal induzida pelo consumo de Ipomoea verbascoidea (Convolvulaceae) em caprinos no semiárido de Pernambuco
O objetivo deste trabalho foi reproduzir a intoxicação por Ipomoea verbascoidea em caprinos e descrever os aspectos epidemiológicos, clínicos e histopatológicos da intoxicação espontânea por essa planta no Estado de Pernambuco. Para isso, realizou-se o acompanhamento da epidemiologia da doença em sete municípios do semiárido pernambucano. Três caprinos espontaneamente intoxicados foram examinados e, em seguida eutanasiados e necropsiados (Grupo I). Para reproduzir experimentalmente a doença, as folhas secas de I. verbascoidea contendo 0,02% de swainsonina, foram fornecidas na dose de 4g/kg (0,8mg de swainsonina/kg) a dois grupos de três animais. Os caprinos do Grupo II receberam a planta diariamente por 40 dias e foram eutanasiados no 41º dia de experimento. Os caprinos do Grupo III receberam a planta diariamente por 55 dias e foram eutanasiados no 120º dia de experimento. Outros três caprinos constituíram o grupo controle (Grupo IV). Nos grupos experimentais, as lesões encefálicas foram avaliadas por histopatologia e adicionalmente avaliaram-se as lesões cerebelares por morfometria, mediante mensuração da espessura da camada molecular, do número de neurônios de Purkinje e da área dos corpos celulares dessas células. Os principais sinais clínicos e lesões microscópicas foram semelhantes aos previamente reportados em animais intoxicados por plantas que contem swainsonina. Nos caprinos do GII e GIII, os primeiros sinais clínicos foram observados entre o 22º e 29º dia de experimento; clinicamente a doença desenvolvida por esses animais foi semelhante aos casos espontâneos. Nenhum dos caprinos do GIII se recuperou dos sinais neurológicos. Esse resultado evidencia que o consumo da planta por 26-28 dias após a observação dos primeiros sinais clínicos é suficiente para provocar lesões irreversíveis. Pela análise morfométrica, a camada molecular do cerebelo dos caprinos do Grupo I e III eram mais delgadas que às dos caprinos do grupo controle, e os neurônios de Purkinje estavam atróficos. Sugere-se que essas alterações sejam responsáveis pelo quadro clínico neurológico observado nos caprinos que deixam de ingerir a planta e apresentam seqüelas da intoxicação
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