排序方式: 共有112条查询结果,搜索用时 31 毫秒
41.
Cristian R Bulboa Juan E Macchiavello Eurico C Oliveira & Erika Fonck 《Aquaculture Research》2005,36(11):1069-1074
Chondracanthus chamissoi is an important source of carrageenan in Chile. Presently, all the production is harvested from wild populations. This study reports the first attempt to cultivate C. chamissoi. Experiments were conducted with female gametophytic and sporophytic thalli by inserting them among braids of a 7 mm polypropylene rope. Inoculated ropes were placed at 1, 3 and 5 m depths in two sheltered bays in northern Chile. The fronds adapted well to cultivation and grew at all the depths tested, although the greatest increase in biomass was observed at 1 m depth. On a yearly cycle, higher biomass increases were observed in autumn and winter months compared with the spring and summer. We believe that by adapting the cultivation methodology, this species could be cultivated year round. 相似文献
42.
Rossi M Caruso F Opazo C Salciccioli J 《Journal of agricultural and food chemistry》2008,56(22):10557-10566
The mechanism by which the naturally occurring polyphenolic compounds resveratrol (RES), C(14)H(12)O(3), and its metabolite piceatannol (PIC), C(14)H(12)O(4), scavenge free radicals is studied using experimental and density functional theory (DFT) methods. PIC's crystal structure shows a strong intermolecular hydrogen bond network, which, through a concerted motion of the hydroxyl hydrogen atoms, can produce a second hydrogen bond chain. This reorganization offers a low-energy pathway for the transfer of hydrogen atoms and is a contributing factor to PIC's biological activity. Additionally, DFT calculations describing the entire reaction mechanism of RES, PIC, and 3,3',4',5,5'-pentahydroxystilbene with hydroxyl and peroxyl radicals agree with experimental results, showing that increased hydroxylation aids in scavenging activity. PIC is more efficient than RES because (i) by sharing its 3'-OH hydrogen atom with its adjacent neighbor, O-4', the abstraction and transfer of the 4'-H atom to the free radical becomes easier and (ii) the resulting PIC semiquinone radical is more stable. As a result of the reaction with OH(*), both RES and PIC form water; with the peroxyl radical, both RES and PIC form hydrogen peroxide. Also, docking of PIC onto the protein transthyretin suggests better performance than RES and confirms its possible application in neurodegenerative conditions such as Alzheimer's disease. 相似文献
43.
Environmental and anthropogenic risk factors for highly pathogenic avian influenza subtype H5N1 outbreaks in Romania, 2005−2006 总被引:1,自引:0,他引:1
The association between highly pathogenic avian influenza (HPAI) subtype H5N1 outbreak risk in poultry in 161 Romanian villages
(October 2005 to June 2006) and environmental and anthropogenic factors was investigated. Village outbreak risk was associated
with a village being <5 km from a major road (odds ratio [OR] 5.27, 95% confidence interval [CI] 1.21–22.9) or a river/stream
(OR 1.97, 95% CI 1.06–3.72). Outbreak risk in the first part of the epidemic was associated with a village being <5 km from
a major road (OR 3.31, 95% CI 1.10–9.98) or a regularly flooded land area (OR 5.08, 95% CI 1.08–23.9); whereas outbreak risk
in the second part of the epidemic was associated with a village being <5 km from a river/stream (OR 5.5, 95% CI 1.69–18.9).
Results suggest that both environmental and anthropogenic factors influence the risk of HPAI subtype H5N1 outbreaks in village
poultry populations. 相似文献
44.
45.
Stefania Nin William Antonio Petrucci Edgardo Giordani Cristian Marinelli 《The Journal of Horticultural Science and Biotechnology》2018,93(3):323-335
Yield and quality of wild strawberry (Fragaria vesca L.) cultivars ‘Regina delle Valli’ and ‘Alpine’ cultivated in soil, as the traditional production system, and in soilless (both in open air and protected environments), as an innovative and sustainable production system, were investigated in a marginal and inner area of the Pistoiese Apennine Mountains during two production seasons. An earlier marketable production was obtained in soilless culture, but total marketable yield was higher from plants grown in a traditional open-field environment. Fruits obtained from the protected soilless system were larger, but developed some mildew, had some visual defects, and revealed a reduced skin chroma index, flesh firmness, and total soluble solids content compared to fruits harvested from plants grown under direct sunlight, while no significant differences were observed in total titratable acidity and pH between growing systems. ‘Alpine’ was more suited to soilless protected cultivation, with a much higher yield compared to ‘Regina delle Valli’. Physicochemical properties of berries were not affected by the cultivar, but fruit quality changed with plant age and seasonal crop cycle. ‘Alpine’ fruits gained a greater sensorial preference, both in traditional soil and soilless culture. 相似文献
46.
Cristian Paltineanu Mihai Coman Silvia Nicolae Irina Ancu Mirela Calinescu Monica Sturzeanu Emil Chitu Mihaela Ciucu Claudia Nicola 《Erwerbs-Obstbau》2018,60(3):187-193
The paper deals with the spatial distribution of root density in highbush blueberry plantations of various ages for a proper planting distance recommendation and a better irrigation and fertilization management. The environmental conditions consist of sandy-loamy soils and a continental temperate climate. Two highbush blueberry cultivars were studied, ‘Bluecrop’ and ‘Blueray’. Root density (RD) and density of root cross-sectional area (RCSA) were investigated for various root diameters. It was found that the prevalent type of roots in highbush blueberry crops is the hair type, with root diameters less than 0.1?mm. Both RD and RCSA decreased with distance from plant and with soil depth; the 38-year-old crop showed a more developed root system versus the 8?year-old crop. In both cases the roots did not grow more than 0.6?m laterally and more than 0.7?m deep. According to these results, the planting distances in highbush blueberry could be reduced to substantially increase the number of plants/ha and fruit yield. Irrigation application should be carried out to wet a proper soil volume, about 0.6–0.7?m deep for older crops, and about 0.5?m deep for younger crops. 相似文献
47.
James Rodríguez-Echeverry Cristian Echeverría Carlos Oyarzún Luis Morales 《Landscape Ecology》2018,33(3):439-453
Context
Land-use change impacts biodiversity and ecosystem services, which are intrinsically related. There is a serious lack of knowledge concerning on how land-use change affects this relationship at landscape level, where the greatest impacts have been reported. A proper knowledge of that relationship would provide crucial information for planning conservation strategies. The forest landscape of southern Chile, which includes Valdivian Temperate Forest, has been designated as a hotspot for biodiversity conservation. However, this landscape has been transformed by land-use change.Objective
We evaluated the impact of land-use change on the spatial patterns of the diversity of native forest habitat and the influence of these impacts on the provision of the ecosystem services water supply, erosion control, and organic matter accumulation from 1986 to 2011.Methods
The evaluation, at the landscape level, was carried out using satellite images, landscape metrics, spatially explicit models and generalized linear models. Results: We found that the area loss of native forest habitat was 12%, the number patches of native forest habitat increased more than 150% and the Shannon diversity index decreased by 0.20. The largest decrease in the provision of services was recorded for erosion control (346%), and the smallest for water supply (11%).Conclusions
The loss of provision of the ecosystem services can be explained by the interaction between the area loss, increase in the number patches and diversity loss. We recommend that the conservation planning strategies should consider the current landscape configuration, complemented with land-use planning.48.
Ecosystem services in changing landscapes: An introduction 总被引:3,自引:3,他引:0
Louis Iverson Cristian Echeverria Laura Nahuelhual Sandra Luque 《Landscape Ecology》2014,29(2):181-186
The concept of ecosystem services from landscapes is rapidly gaining momentum as a language to communicate values and benefits to scientists and lay alike. Landscape ecology has an enormous contribution to make to this field, and one could argue, uniquely so. Tools developed or adapted for landscape ecology are being increasingly used to assist with the quantification, modelling, mapping, and valuing of ecosystem services. Several of these tools and methods encased therein are described among the eleven papers presented in this special issue, and their application has the potential to facilitate the management and promotion of services within ecosystems. Papers are associated with each of the four key categories of services that ecosystems provide to humans: supporting, provisioning, regulating, and cultural. The papers represent work conducted in eleven different countries, especially from South America. Each carries a unique approach to address a particular question pertaining to a particular set of ecosystem services. These studies are designed to inform and improve the economic, environmental and social values of the ecosystem services. This knowledge should help to develop new management alternatives for sustaining and planning ecosystems and the services they provide at different scales in space and time. We believe that these papers will create interest and inform management of some potential methods to evaluate ecosystem services at the landscape level with an integrative approach, offering new tools for management and conservation. 相似文献
49.
Cristian Valeriu Patriche 《Soil Use and Management》2019,35(2):257-272
Soil erosion is an important geomorphological process with potential negative consequences especially on land agricultural potential. Unsuitable agricultural practices may increase soil erosion, leading to rapid loss of soil fertility and decrease of crop production. It is therefore important to correctly quantify soil erosion rates in order to adapt agricultural practices and implement proper conservation measures. This study attempts to assess the rill and interrill erosion in Romania, using the Romanian soil erosion model and GIS techniques. The database includes the digital terrain model, the soil map of Romania, the land use map of Romania and the rainfall erosivity regions. The results show that the high and very high erosion risk classes include 4.1% of the Romanian territory (9,627 km2). Most of this land is present in the hilly and plateau areas (Subcarpathians, Moldavian Plateau, Getic Plateau, Western Hills, Dobrogea Plateau). The model was validated by comparison of its predictions with long‐term erosion measurements from different locations in the country. Comparison with previous non‐GIS assessments of soil erosion at national level shows that the total estimated rill and interrill erosion in our study was very close to previous estimates. Comparison with the RUSLE 2015 model computed for Europe as a whole reveals that the two models assign almost 54% of their shared area to the same erosion class, while for 39% of the territory there is one class difference between the models. The results can be used for evaluations of erosion risk at national and regional scales. 相似文献
50.
C Del Bo' P Riso A Brambilla C Gardana A Rizzolo P Simonetti G Bertolo D Klimis-Zacas M Porrini 《Journal of agricultural and food chemistry》2012,60(36):9298-9304
Blueberries ( Vaccinium corymbosum L.) are rich sources of phenolics and anthocyanins (ACNs). We investigated the absorption of ACNs after consumption of one portion (300 g) of minimally processed blueberry purée (P) obtained from blanched (BL) or unblanched (NB) berries. A repeated-measures, crossover design study was conducted on healthy human volunteers. Blood was drawn between baseline and 24 h after BL-P or NB-P consumption, while urine were collected from the day before the experiment up to 48 h. Total plasma ACN content was not significantly different, while phenolics content was higher in BL-P with respect to NB-P. The maximum ACN absorption in plasma was observed after 1.5 h from the intake of the purées and was significantly higher (p ≤ 0.05) after the intake of BL-P. Both products increased the excretion of hippuric acid in urine. In conclusion, blanching had no significant effect on total ACN content and enhanced their absorption from minimally processed purées. 相似文献