Site index estimation in Scots pine (Pinus sylvestris L.) stands in the High Ebro Basin (northern Spain) using soil attributes     

Bravo  F.; Montero  G. 《Forestry》2001,74(4):395-406

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SIRIAS: a simulation model for sprinkler irrigation     

P. Carrión  J. Tarjuelo  J. Montero 《Irrigation Science》2001,20(2):73-84

Uniformity of distribution in irrigation systems plays an important role in the optimum use of irrigation water, with direct repercussions on water-use efficiency and production. To evaluate the effects of the wind on sprinkler water uniformity, it is necessary to measure infield water distribution under different wind conditions and then calculate the parameters that define water distribution. This paper perfects the SIRIAS simulation model for sprinkler systems, which can be used to design new irrigation installations or to improve existing ones. Using ballistic theory to simulate the trajectory of drops discharged by the sprinkler, the model obtains wind-distorted water distribution, with a new formulation for the air drag coefficient. It takes into account three options to distribute the evaporation and drift losses in the irrigation process. SIRIAS software has been programmed using Delphi language for Windows 95, 98 and NT.  相似文献   

Analysis of the role of sidewall vents on buoyancy-driven natural ventilation in parral-type greenhouses with and without insect screens using computational fluid dynamics   总被引：2，自引：0，他引：2  

Esteban J. Baeza  Jernimo J. Prez-Parra  Juan I. Montero  Bernard J. Bailey  Juan C. Lpez  Juan C. Gzquez 《Biosystems Engineering》2009,104(1):86-96

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Pseudoallencotyla gen. n., a new genus for Allencotyla pricei (Kritsky,Noble et Moser, 1978) (Monogenea: Heteraxinidae), with a key to genera of Heteraxininae     

Montero FE  Aznar FJ  Fernández M  Raga JA 《Folia parasitologica》2003,50(1):43-47

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Natural abundance N in soil and litter across a nitrate-output gradient in New Hampshire     

L.H. Pardo  H.F. Hemond  J.P. Montoya  J. Pett-Ridge 《Forest Ecology and Management》2007

Stable isotopes of nitrogen are potentially a valuable tool for regional assessments of nitrogen saturation because they provide an integrated measure of the past nitrogen cycling history of a site. We measured δ¹⁵N of soil and litter, as well as net nitrification potential, at three sites across a nitrate-loss gradient in the White Mountains, New Hampshire to test the hypotheses: (1) that δ¹⁵N in soil and litter increase across a spatial gradient of nitrate loss; and (2) that δ¹⁵N in soil and litter is elevated when nitrification is elevated. δ¹⁵N was found not to vary significantly among the three sites. Patterns of leaf litter and forest floor δ¹⁵N, however, were strongly influenced by species composition in individual plots. Beech litter had significantly higher δ¹⁵N than yellow birch, sugar maple, and red maple. The conifer-dominated plots had significantly lower δ¹⁵N in both the organic soil horizons and in litter than did the hardwood-dominated plots. When we adjusted for spatial heterogeneity in mineral soil δ¹⁵N values by using an enrichment factor, δ¹⁵N_foliar − δ¹⁵N_Bs, in place of absolute soil δ¹⁵N values, a positive relationship was found with net nitrification for hardwoods. δ¹⁵N may also be a useful tool for evaluating species differences in nitrogen cycling and nitrogen uptake. The distinct pattern we observed of decreasing δ¹⁵N across the continuum from hardwood-dominated to conifer-dominated sites may suggest that local drivers (for example, nitrification rate) regulate the absolute value of foliar δ¹⁵N, while species-driven factors (e.g., timing and type of uptake) control the foliar δ¹⁵N value of one species relative to another in the same plot.  相似文献   

Depletion of serum alternative complement pathway activity in gilthead seabream caused by α-tocopherol and n-3 HUFA dietary deficiencies     

D. Montero  L. Tort  M.S. Izquierdo  L. Robaina  J.M. Vergara 《Fish physiology and biochemistry》1998,18(4):399-407

Studies on the alternative complement pathway (ACP) activity in fish have suggested the particular relevance of this pathway as a non-specific immune mechanism being its activation directly related with the availability of certain nutrients. In the present study ACP activity in gilthead seabream fed different dietary levels of a-tocopherol and n-3 HUFA deficiencies was studied under different stress conditions (overcrowding and repetitive chasing).A reduction in ACP activity was found when diets with deficiencies in -tocopherol and n-3 HUFA were assayed at any of the experimental conditions assayed. Levels of plasma cortisol were similar to those of fish after crowding stress subjected to dietary deficiencies at low stocking density, suggesting that dietary deficiencies produced a chronic elevation of cortisol. When fish were subjected to repetitive chasing, plasma cortisol from fish fed control diet showed a progressive increase whereas plasma cortisol levels from both dietary deficient groups showed a transitory peak 4 days after the beginning of the repetitive chasing. However, ACP activity levels of fish fed deficient diets remained lower than the control group and constant during chasing period. These results suggest that both a-tocopherol and n-3 HUFA nutritional deficiencies rather than stress are an important determinant of fish complement activity.  相似文献   

Differential distribution and response to experimental sexual maturation of two forms of brain gonadotropin-releasing hormone (GnRH) in the European eel,Anguilla anguilla     

Sylvie Dufour  Maïté Montero  Nadine Le Belle  Marc Bassompierre  Judy A. King  Robert P. Millar  Richard E. Peter  Yves-Alain Fontaine 《Fish physiology and biochemistry》1993,11(1-6):99-106

Using specific radioimmunoassays for the two GnRH molecular forms present in the European eel, Anguilla anguilla, (mGnRH and cGnRH II), we compared their distributions in the pituitary and different parts of the brain of female silver eels, as well as the modifications of their levels in experimentally matured female eels (treated with carp pituitary extract). In control eels, mGnRH levels were higher than cGnRH II levels in the pituitary, olfactory lobes and telencephalon, di- and mesencephalon, while the opposite was found in the posterior part of the brain (met- and myelencephalon). Experimental sexual maturation of the gonads significantly increased mGnRH levels in the pituitary and anterior parts of the brain; such a positive effect was not observed on the low cGnRH II levels, which were, in contrast, reduced. These data indicate that the positive feedback of gonadal hormones on GnRH, that we previously demonstrated, would specifically affect the mGnRH form. The differential distribution and control of mGnRH and cGnRH II suggest that these two forms have different physiological roles in the eel. The large increase in mGnRH during sexual maturation suggests the prime implication of this form in the neuroendocrine control of reproduction.  相似文献   

Alteration of liver and muscle fatty acid composition in gilthead seabream (Sparus aurata) juveniles held at high stocking density and fed an essential fatty acid deficient diet   总被引：2，自引：0，他引：2  

D. Montero  L.E. Robaina  J. Socorro  J.M. Vergara  L. Tort  M.S. Izquierdo 《Fish physiology and biochemistry》2001,24(1):63-72

The aim of the present study was to determine the combined effect of both stress and EFA deficiency on several biological and biochemical parameters. Fish were fed during 15 weeks two isocaloric and isoproteic diets: a control diet based on fish oil and formulated to meet the n-3 HUFA requirements for this species (1.5% of n-3 HUFA) and a deficient diet containing beef tallow and formulated to be deficient in n-3 HUFA. Each experimental diet was evaluated both at high and low stocking densities (10 and 3.2 kg m^–3 of initial density, respectively).High stocking density produced a chronic stress situation with elevation of plasma cortisol levels. It also caused a reduction in hepatosomatic index and liver lipid contents, increasing the oleic acid/n-3 HUFA ratios in the polar lipids. Fish fed the EFA deficient diet at low stocking density showed common deficiency symptoms. High stocking density in fish fed the EFA deficient diet induced a higher degree of EFA deficiency symptoms leading to mortality, liver steatosis, liver lipid deposition, reduced muscle lipid and reduced n-3 HUFA contents, which particularly affected EPA, but not DHA, suggesting a preferential retention of the latter fatty acid, specially in the phosphoglycerides fraction.  相似文献   

Effect of red grapes co-winemaking in polyphenols and color of wines   总被引：1，自引：0，他引：1  

Lorenzo C  Pardo F  Zalacain A  Alonso GL  Salinas MR 《Journal of agricultural and food chemistry》2005,53(19):7609-7616

The red grapes co-winemaking effect on phenolic fraction and wine color has been studied for the first time, where Monastrell was comacerated and cofermentated with Cabernet Sauvignon and Merlot. Changes in the relative abundance of anthocyanins were observed as well as hyperchromic shifts at 530 and 620 nm; these effects remain constant after aging. Co-winemaking also favored copigmentation, giving way to more stable anthocyanins and facilitating their polymerization. With regard to color evolution, the mixture of Monastrell with Merlot grapes was more appropriate than with Cabernet Sauvignon for aging wines in oak barrels. The extent of copigmentation was more important in young wines than in aged wines. This is mainly due to the self-anthocyanin monomer reactions in the case of young wines, whereas in aged wines copigmentation is mainly due to the reaction between the anthocyanins and other polyphenolic cofactors. Discriminant analysis showed the possibility of differentiating wines according to the aging time and the type of wine, with color parameters (color intensity, OD 620 nm, and OD 520 nm) being the most important discrimination variables in the first case and petunidin-3-glucoside and peonidin-3-glucoside contents in the second case.  相似文献   

Equatorial retention of the contractile actin ring by microtubules during cytokinesis     

Pardo M  Nurse P 《Science (New York, N.Y.)》2003,300(5625):1569-1574

In most eukaryotes cytokinesis is brought about by a contractile actin ring located at the division plane. Here, in fission yeast the actin ring was found to be required to generate late-mitotic microtubular structures located at the division plane, and these in turn maintained the medial position of the actin ring. When these microtubular structures were disrupted, the actin ring migrated away from the cell middle in a membrane traffic-dependent manner, resulting in asymmetrical cell divisions that led to genomic instability. We propose that these microtubular structures contribute to a checkpoint control that retains the equatorial position of the ring when progression through cytokinesis is delayed.  相似文献