3,318 research outputs found
Cuttings of Aloysia citriodora Palau: greenhouse trials under different rooting conditions
A espécie aromática e medicinal Aloysia citrodora Palau, Verbenaceae, conhecida como limonete, erva -luÃsa ou lúcia-
-lima, é uma das mais cultivadas e comercializadas em Portugal. A instalação e manutenção dos campos de cultivo
exigem material de propagação em quantidade e com a qualidade e uniformidade que assegurem a comercialização
da biomassa, de acordo com os padrões dos compradores. A possibilidade dos produtores obterem as próprias plantas
depende da disponibilidade de material vegetativo ao longo de todo o ano e dos processos de rizogénese que nem
sempre são fáceis de induzir.
Realizaram -se ensaios de enraizamento de estacas caulinares lenhosas e semilenhosas, preparadas a partir de plantas-
-mãe cultivadas em campo comercial ao ar livre. O delineamento experimental incluiu estacas caulinares de diferente
espessura, diferentes substratos (perlite e composto orgânico comercial), hormona de enraizamento (com e sem auxina),
condições de humidade (com e sem nebulização) e temperatura (em bancada aquecida e sem aquecimento). Numa
segunda experiência avaliou -se a capacidade de enraizamento de material vegetal colhido ao longo de todos os meses
do ano a partir de plantas cultivadas em estufa.
As estacas colocadas em perlite originaram percentagens de enraizamento mais elevadas do que as estacas em substrato
orgânico, embora os valores tenham sido sempre inferiores a 20%. O substrato orgânico deu melhores resultados, conjugando
estacas grossas e ausência de nebulização, por oposição a estacas mais finas com nebulização. Ao longo do ano,
as percentagens de enraizamento foram máximas em maio, com valores superiores a 70%. As estacas semilenhosas do
perÃodo estival originaram percentagens de enraizamento particularmente baixas.Aloysia citriodora Palau, Verbenaceae, known as lemon verbena, is one of the most cultivated and marketed medicinal
and aromatic plants in Portugal. Biomass quality and uniformity of the plant material according to stakeholders’ standards
are market criteria requiring important amounts of biomass supplied by producers’ organic fields. However, in
order to satisfy such biomass needs, horticulturists should provide vegetative propagated plant material to install new
fields or to regenerate the existing ones. Producing cuttings depends on the availability of plant material throughout
the year and on rooting processes which could not be easy to induce.
Woody and softwood stem cuttings were prepared from plants grown in the field. Different substrates, thickness of
propagated material and exogenous application of auxin were compared in their capability to induce root and shoot
formation. In other experiment, the rhizogenic ability of plant material was monthly assessed for a year from plants
grown in a greenhouse.
Cuttings placed in perlite presented higher percentages of rooting than those in organic substrate, although in both
cases values of root formation were always below 20%. Organic substrate combined with thick cuttings and absence of
nebulization had a better performance than thin cuttings with nebulization. Throughout the year, the rooting percentages
were highest in May, with values greater than 70%. The softwood cuttings from summer period originated particularly
low rooting percentagesinfo:eu-repo/semantics/publishedVersio
Estacaria de Aloysia citrodora Palau: ensaios de enraizamento em estufa sob diferentes condições
A espécie Aloysia citrodora Palau, Verbenaceae, conhecida como limonete, erva-LuÃsa ou lúcia-lima, é uma das espécies de PAM mais cultivadas e comercializadasem Portugal.
Segundo alguns produtores, no momento da instalação e regeneração dos campos de produção ou da mera substituição de falhas, a obtenção de material vegetativo, em quantidade e com as caracterÃsticasde qualidade e uniformidade (e.g. textura, consistência, cor, aroma, composição quÃmica) que garantem a comercialização da biomassa está dependente da disponibilidade dos viveiristas ou da capacidade dos produtores produzirem as próprias plantas.
A propagação vegetativa, nomeadamente a estacaria, pode ser uma respostaajustada à s necessidades. Contudo, nem sempre os resultados são favoráveis porque a produção de estacas durante todo o ano está limitada à disponibilidade de material vegetativo e os processos de rizogénese podem ser difÃceis de induzir, não ocorrendo a formação de raÃzes ou obtendo-se um sistema radicular deficiente, que provoca a secagem e mortalidade das estacas. Com o objectivo de obter informação sobre as taxas de enraizamento de estacaria de limonete realizaram-se ensaios de enraizamento de estacas caulinares, lenhosas e semilenhosas, preparadas a partir de plantas cultivadas e mantidas em estufa. Numa primeira etapa, ensaiaram-se substratos e condições de temperatura e humidade. Na segunda fase, testou-se a capacidade de enraizamento de material vegetal colhido ao longo de todos os meses do ano.info:eu-repo/semantics/publishedVersio
Statistical assessment of feeding corn with higher oil content to piglets in the starter phase
The aim of this study was to assess the digestibility coefficients (DC) of corn [maize] with an oil content above 3.46% and its effects on the performance of piglets when fed as dry grain (DG) and as rehydrated corn grain silage (RCGS). In Experiment I, 15 piglets (22.51 + 2.39 kg) were allocated to a reference diet (RD) and to two test diets in which corn in the RD was replaced with DG or RCGS. There were five replications of each treatment. Experiment II involved 36 piglets (14.76 ± 2.72 kg), which were assigned to a control diet with common corn grain and to diets in which DG or RCGS replaced the common corn. There were six replications of each treatment. Data were analysed with four statistical models. Model 1 included only the effect of treatment. Model 2 was similar to Model 1 but included initial bodyweight as a covariate. Model 3 was similar to model 1 but included the interaction of diet and period. Model 4 was similar to Model 3 but included the covariate. The more complicated models were generally preferred to Model 1 as they controlled more of the nuisance variation. Feeding a diet that contained RCGS reduced feed intake and improved feed conversion ratio (FCR)
Growth And Characterization Of Gaas On Si By Vacuum Chemical Epitaxy
Undoped GaAs epitaxial layers have been grown on Si substrates by vacuum chemical epitaxy. Triethylgallium and arsine were used as gallium and arsenic sources, respectively. The layers have shown KOH etch pit densities in the range 7×106-2×107 cm-2 and residual hole concentration of 1015 cm-3. The layer crystallinity was found to be strongly influenced by the substrate preparation and also by the water partial vapor pressure in the growth chamber.69273273
New findings on the dynamics of HIV and TB coinfection models
In this paper we study a model for HIV and TB coinfection. We consider the integer order and the fractional order versions of the model. Let α∈[0.78,1.0] be the order of the fractional derivative, then the integer order model is obtained for α=1.0. The model includes vertical transmission for HIV and treatment for both diseases. We compute the reproduction number of the integer order model and HIV and TB submodels, and the stability of the disease free equilibrium. We sketch the bifurcation diagrams of the integer order model, for variation of the average number of sexual partners per person and per unit time, and the tuberculosis transmission rate. We analyze numerical results of the fractional order model for different values of α, including α=1. The results show distinct types of transients, for variation of α. Moreover, we speculate, from observation of the numerical results, that the order of the fractional derivative may behave as a bifurcation parameter for the model. We conclude that the dynamics of the integer and the fractional order versions of the model are very rich and that together these versions may provide a better understanding of the dynamics of HIV and TB coinfection
A coinfection model for HIV and HCV
We study a mathematical model for the human immunodeficiency virus (HIV) and hepatites C virus (HCV) coinfection. The model predicts four distinct equilibria: the disease free, the HIV endemic, the HCV endemic, and the full endemic equilibria. The local and global stability of the disease free equilibrium was calculated for the full model and the HIV and HCV submodels. We present numerical simulations of the full model where the distinct equilibria can be observed. We show simulations of the qualitative changes of the dynamical behavior of the full model for variation of relevant parameters. From the results of the model, we infer possible measures that could be implemented in order to reduce the number of infected individuals
Communitarian and urban gardens in Bragança, Portugal
Since 2011, the Polytechnic Institute of Bragança (IPB), through the Cultural and Recreational Association, welcomes and sponsors a project of communitarian urban gardens carried out in the arable land of its campus. The project was designed to promote community gardening at leisure time, while focusing on organic and sustainable agricultural practices, providing healthy produce and fresh plants, as well as satisfying labor, neighborhood improvement, sense of community, connection to the environment and nature, and fostering interaction between users, which come from a broad geographical origin and have different gardening background and knowledge.
In order to report motivation, agricultural performances, inventory all species grown, and to estimate the total production, we surveyed 51 gardens and we did consented interviews to 88 users from a total of 120.The authors are grateful to all the informants who kindly shared their knowledge and expertise.
Strategic project PEst-OE/AGR/UI0690/2011 for CIMO financial support.info:eu-repo/semantics/publishedVersio
Effects of proportional assisted ventilation on exercise performance in idiopathic pulmonary fibrosis patients
SummaryBackgroundPatients with idiopathic pulmonary fibrosis (IPF) present an important ventilatory limitation reducing their exercise capacity. Non-invasive ventilatory support has been shown to improve exercise capacity in patients with obstructive diseases; however, its effect on IPF patients remains unknown.ObjectiveThe present study assessed the effect of ventilatory support using proportional assist ventilation (PAV) on exercise capacity in patients with IPF.MethodsTen patients (61.2±9.2 year-old) were submitted to a cardiopulmonary exercise testing, plethysmography and three submaximal exercise tests (60% of maximum load): without ventilatory support, with continuous positive airway pressure (CPAP) and PAV. Submaximal tests were performed randomly and exercise capacity, cardiovascular and ventilatory response as well as breathlessness subjective perception were evaluated. Lactate plasmatic levels were obtained before and after submaximal exercise.ResultsOur data show that patients presented a limited exercise capacity (9.7±3.8mLO2/kg/min). Submaximal test was increased in patients with PAV compared with CPAP and without ventilatory support (respectively, 11.1±8.8min, 5.6±4.7 and 4.5±3.8min; p<0.05). An improved arterial oxygenation and lower subjective perception to effort was also observed in patients with IPF when exercise was performed with PAV (p<0.05). IPF patients performing submaximal exercise with PAV also presented a lower heart rate during exercise, although systolic and diastolic pressures were not different among submaximal tests. Our results suggest that PAV can increase exercise tolerance and decrease dyspnoea and cardiac effort in patients with idiopathic pulmonary fibrosis
Assessing the Effect of Plant Biostimulants and Nutrient-Rich Foliar Sprays on Walnut Nucleolar Activity and Protein Content (Juglans regia L.)
The cultivation of walnuts (Juglans regia L.) has become increasingly popular worldwide due to the nutritional value of the nuts. Plant biostimulants (PBs) and nutrient-rich products have been increasingly used in agriculture to improve yield, quality, and abiotic stress tolerance. However, farmers need fast laboratory studies to determine the most suitable treatment per crop or ecosystem to take full advantage of these products. Evaluating nucleolar activity and protein content can provide clues about the most appropriate treatment. This study aimed to determine how five commercial products, four PBs based on seaweed extract and/or free amino acids and one boron-enriched fertiliser used as foliar sprays, affect walnut cv's nucleolar activity and protein content. "Franquette" from an orchard located in NE Portugal was compared to untreated (control) plants. All treatments brought a low leaf mitotic index. The control showed the smallest nucleolar area, highest protein content, and highest frequency of nucleolar irregularities. Fitoalgas Green (R), Sprint Plus (R), and Tradebor (R) showed the highest nucleolar area and lowest frequencies of nucleolar irregularities. The recruitment of proteins/enzymes for response against abiotic stresses may explain the high protein content in the control. Hence, the enhanced abiotic stress tolerance of the treated trees explains their lower protein content and frequency of nucleolar anomalies. Globally, the Fitoalgas Green (R), Sprint Plus (R), and Tradebor (R) seem better suited for "Franquette" walnut trees under the edaphoclimatic conditions where trials were conducted.This research was funded by national funds provided by the Fundação para a Ciência
e a Tecnologia (FCT) to CITAB (UIDB/04033/2020) and CIMO (UIDB/00690/2020). This research
was integrated in the Operational Group EGIS: Estratégias para uma gestão integrada do solo e da
água em espécies produtoras de frutos secos activities funded by Portugal 2020 and the European
Agricultural Fund for Rural Development (EAFRD). The author Ana Carvalho thanks the funding attributed by the Fundação para a
Ciência e a Tecnologia (FCT) with the reference DL 57/2016/CP1378/CT0003 (doi10.54499/DL57/
2016/CP1378/CT0003), which allowed her to be hired by UTAD as a doctorate researcher through
the D.L. no. 57/2016 and Law no. 57/2017.info:eu-repo/semantics/publishedVersio
- …