105 research outputs found

    Métodos de amostragem para avaliação quantitativa de pastagens.

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    O objetivo deste trabalho foi levantar as principais técnicas utilizadas para coleta de amostras para determinação de forragem disponível na pastagem, considerando-se as vantagens e desvantagens de cada uma, visando fornecer subsídios para a tomada de decisão na hora de escolher o método mais adequado para cada situação.bitstream/item/24669/1/ct84-pastagem.pd

    Degradation Risk Assessment: Understanding the Impacts of Climate Change on Geoheritage

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    Several factors and processes, both natural and anthropogenic, can threaten the integrity of any geosite, leading to their degradation. For this reason, geoheritage degradation risks should be considered a fundamental step in any geoconservation strategy, all the more when the aim is to tackle the effects of climate change. The present work proposes a quantitative methodology for the degradation risk assessment of geosites by considering the extrinsic factors that can damage the geoheritage. The methodology has been tested on the Maltese Islands, where considerable previous research has been undertaken in order to highlight the international significance of the Maltese landscapes. Three criteria to assess the degradation risk are proposed: natural vulnerability, anthropogenic vulnerability and public use. For each criterion, several parameters have been identified in order to propose a detailed numerical evaluation. The results show that the degradation risk of geosites is mainly related to negligence and lack of knowledge of its inherent geological heritage, and which leads to public misuse and mismanagement of the geosites. The results give an overview of the condition of the geosites and provide information for the design and management of suitable protection measures, especially in the light of future threats related to climate change

    Seasonal Occurrence and Distribution on Grapevine Roots of Eurhizococcus brasiliensis (Wille) (Hemiptera: Margarodidae) in Brazil

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    The ground pearl, Eurhizococcus brasiliensis (Wille) (Hemiptera: Margarodidae), is the most importantgrapevine pest in Brazil. Its seasonal occurrence and distribution on the roots of the different developmentstages were determined to allow better monitoring of this insect and better targeting of its vulnerable lifestages. Yellow cysts (after the first nymphal moult) showed the lowest density in October, followed by agradual increase towards August. White cysts (cysts with enclosed pre-pupal males or females) occurredfrom August to December, with a peak in November. Mobile females (adult females emerging from thewhite cysts) were found from August to December, with a peak in August. Parthenogenetic females thatremain in the ruptured white cysts for egg laying were present from August to April, with a peak inNovember. Mobile nymphs (first instar) were also found from August to April, with a peak in December.Yellow cysts were most abundant at depths of 0 to 25 cm. The horizontal survey showed that cysts occurredmostly on the trunk below the ground (trunk of the rootstock), and that almost all occurred in an area of20 cm width around the trunk. These results provide important information for better monitoring of thispest and to develop better methods for and timing of chemical control

    Effects of supplementation frequency on the ruminal fermentation and enteric methane production of beef cattle grazing in tropical pastures.

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    Abstract: The objective of this study was to evaluate the characteristics of ruminal fermentation and enteric methane production in beef cattle subjected to different supplementation frequencies while grazing on Brachiaria brizantha cv. Marandu pastures. Nine cattle (325±65.7 kg BW) fitted with ruminal and duodenal cannulas were used in the ruminal fermentation study, and 12 cattle (399±32.6 kg BW) were used in the enteric methane production study. The treatments included supplementation once daily, supplementation once daily except Saturdays and Sundays, or supplementation on alternate days. The supplementation was equivalent to 10 g kg ?1 BW day ?1 for all treatments. The design employed was completely randomized with three treatments and three replications. When all supplements were provided (day 1), no effects of supplementation frequency were observed on ruminal pH; concentration of NH 3 -N; concentration of acetic, propionic, or butyric acids; or total volatile fatty acids (VFA), but there were month effects. During the day on which only daily supplements were provided (day 2), significant differences were observed only on the molar concentration of acetic acid and total VFA; and month effects were noted on all variables. No significant differences were observed in ruminal fluid volume, dilution rate, N intake, bacterial N synthesis and enteric methane production among the studied supplementation frequencies. Differences were observed in the enteric methane production in the different months, with 85 g kg ?1 of gross energy intake observed in September and 123 g kg ?1 of gross energy intake observed in November. Lower supplementation frequency is a good option to lower labor costs with little or no consequences on ruminal fermentation characteristics and enteric methane production

    STAT3 inhibition with Galiellalactone effectively targets the prostate cancer stem-like cell population."

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    Cancer stem cells (CSCs) are a small subpopulation of quiescent cells with the potential to differentiate into tumor cells. CSCs are involved in tumor initiation and progression and contribute to treatment failure through their intrinsic resistance to chemo- or radiotherapy, thus representing a substantial concern for cancer treatment. Prostate CSCs’ activity has been shown to be regulated by the transcription factor Signal Transducer and Activator of Transcription 3 (STAT3). Here we investigated the effect of galiellalactone (GL), a direct STAT3 inhibitor, on CSCs derived from prostate cancer patients, on docetaxel-resistant spheres with stem cell characteristics, on CSCs obtained from the DU145 cell line in vitro and on DU145 tumors in vivo. We found that GL significantly reduced the viability of docetaxel-resistant and patient-derived spheres. Moreover, CSCs isolated from DU145 cells were sensitive to low concentrations of GL, and the treatment with GL suppressed their viability and their ability to form colonies and spheres. STAT3 inhibition down regulated transcriptional targets of STAT3 in these cells, indicating STAT3 activity in CSCs. Our results indicate that GL can target the prostate stem cell niche in patient-derived cells, in docetaxel-resistant spheres and in an in vitro model. We conclude that GL represents a promising therapeutic approach for prostate cancer patients, as it reduces the viability of prostate cancer-therapy-resistant cells in both CSCs and non-CSC populations

    Extraction of bioactive compounds from Peruvian purple corn cob by high isostatic pressure

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    The purple corn cob is an agro-industrial by-product that contains high-value bioactive compounds, which makes its use attractive for the development of extraction processes. The aim of this research was to extract the bioactive compounds from the purple corn cob by high isostatic pressure at different processing temperatures. Pressures of 0.01 MPa, 250 MPa, 450 MPa and 650 MPa for 3 minutes and at temperatures of 25 °C, 45 °C and 65 °C were used. High pressure extraction was compared with conventional extraction (2.5 h at 25°C). The purple corn cob extract obtained by isostatic processing at 650 MPa and 65 °C presented high antioxidant activity and content of bioactive compounds, unlike the conventional extraction of 2.5 h and 65 °C (p 0.05). Seven different anthocyanins were identified by liquid chromatography in the extracts obtained by high isostatic pressure (650 MPa at 65 °C) and hydroalcoholic maceration (2.5 h at 65 °C), mainly cyanidin-3-glucoside, pelargonidin-3-glucoside and peonidin-3-glucoside, and their respective malonyl derivatives. The high isostatic pressure increased the extraction of bioactive compounds by more than 50% and obtained them in shorter times, thus appearing as a new alternative, and eco-friendly method for the extraction of bioactive compounds from plant tissues
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