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81.
THE APPLICATION OF TWO FREE-CHOICE PROFILE METHODS TO INVESTIGATE THE SENSORY CHARACTERISTICS OF CHOCOLATE 总被引:1,自引:0,他引:1
The concept of free-choice profiling allows untrained assessors to participate in sensory profiling. However, it is sometimes the case that such individuals are unable to describe what they perceive when the samples are presented in the isolation of the sensory testing booths. This paper reports an experiment to compare the usual free-choice profile procedure, with a more structured approach based on Kelly's repertory grid method. Generalized Procrustes analysis was used to analyse the data. The sample configurations obtained from both approaches were very similar, as were the interpretations of the main perceptual dimensions. 相似文献
82.
A. G. WHITEHEAD D. J. TITE JANET E. FRASER EILEEN M. FRENCH 《The Annals of applied biology》1973,74(1):105-111
Large amounts of dazomet (329, 439 kg/ha) applied to potato ridge soil in spring, before potatoes were planted, controlled potato cyst-nematode (Heterodera rostochiensis) in sandy loam and silt loam more effectively than large amounts of D-D (359, 448 kg/ha). In heavily infested sandy loam, 329 kg dazomet/ha or 857 kg methyl bromide/ha applied in spring 1969 or 439 kg dazomet/ha applied in autumn 1968, greatly decreased the number of larvae able to invade potato roots, so Majestic potatoes grew and yielded well without increasing the number of nematodes left in the soil after harvest. Large amounts of D-D or Telone applied to the topsoil in autumn or to the ridges in spring were less effective in controlling potato cyst-nematode or increasing potato yields. Applied in spring 1969 to silt loam ridges, 439 kg dazomet/ha had more effect than 448 kg D-D/ha on potato cyst-nematode and on the increase in yield of Majestic potato. The yield of Maris Piper potatoes (resistant to H. rostochiensis pathotype A) in infested silt loam was increased greatly by D-D, as much by 112 as by 224 or 448 kg/ha. 相似文献
83.
ISABEL SOTO-CRUZ JANET M. OLIVER ENRIQUE ORTEGA 《Journal of receptor and signal transduction research》2013,33(1):67-81
Aggregation of the multichain (α β γ2) high-affinity IgE receptor (Fcε RI) initiates a signaling cascade that results in the release of allergic mediators. The cytoplasmic tails of the Fcε RI-β and -γ subunits contain immunoreceptor tyrosine-based activation motifs (ITAMs). Phosphorylation of the γ ITAM mediates activation of Syk kinase and is sufficient for triggering the responses induced by Fcε RI crosslinking. Phosphorylation of the β ITAM is insufficient to mediate cell activation. The rat β ITAM contains three tyrosines (Tyr218, Tyr224, and Tyr228) with an intermediate noncanonical tyrosine. Synthetic peptides based on the ITAM of the Fcε RI-β subunit were used to investigate the role of each phosphotyrosine in the binding of signaling proteins to this motif. Among the proteins that bind to phosphorylated β ITAM are Syk, Grb2, Shc, SHIP, and SHP-1, and binding does not depend on previous cell activation. Nonphosphorylated peptides do not bind these proteins. Syk binding to β -peptides is dependent on the number and position of phosphotyrosines in the ITAM. Phosphorylation of Tyr218 seems to be most important for Syk binding. Recruitment of Syk and other signaling proteins to the β -subunit might be important for its amplifier role. 相似文献
84.
This study (1970–71) of an oligotrophic lake subject to cultural enrichment indicates the presence of complex interrelations between plankton and nitrogen levels in surface waters. Generally inorganic nitrogen was high in the winter (0.4–0.5 ppm) and Iow in summer (less than 0-1 ppm). However, in late July and August a large increase in nitrogen (1.5 ppm) was recorded. This correlated with the Gloeotrichia echinulata J. E. Smith ex P. Richt. bloom (Cyanophyceae) and the increase in nitrogen fixation, or nitrogenase activity (measured as acetylene reduction). It was calculated that the cyanophyte bloom could have contributed a minimum of 2350 kg nitrogen to the lake in August 1970 which is c. 62% of the nitrate-nitrogen occurring at any time. 相似文献
85.
86.
GROWTH AND NITROGEN FIXATION IN LUPINUS ARBOREUS AS AFFECTED BY SHADING AND WATER SUPPLY 总被引:4,自引:4,他引:0
JANET I. SPRENT 《The New phytologist》1973,72(5):1005-1022
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89.
JANET E. BERTRAM TIM J. CLOUGH ROBERT R. SHERLOCK LEO M. CONDRON MAUREEN O'CALLAGHAN† NAOMI S. WELLS JESSICA L. RAY 《Global Change Biology》2009,15(8):2067-2077
Atmospheric concentrations of the greenhouse gas nitrous oxide (N2 O) have continued to rise since the advent of the industrial era, largely because of the increase in agricultural land use. The urine deposited by grazing ruminant animals is a major global source of agricultural N2 O. With the first commitment period for reducing greenhouse gas emissions under the Kyoto Protocol now underway, mitigation options for ruminant urine N2 O emissions are urgently needed. Recent studies showed that increasing the urinary concentration of the minor urine constituent hippuric acid resulted in reduced emissions of N2 O from a sandy soil treated with synthetic bovine urine, due to a reduction in denitrification. A similar effect was seen when benzoic acid, a product of hippuric acid hydrolysis, was used. This current laboratory experiment aimed to investigate these effects using real cow urine for the first time. Increased concentrations of hippuric acid or benzoic acid in the urine led to reduction of N2 O emissions by 65% (from 17% to <6% N applied), with no difference between the two acid treatments. Ammonia volatilization did not increase significantly with increased hippuric acid or benzoic acid concentrations in the urine applied. Therefore, there was a net reduction in gaseous N loss from the soil with higher urinary concentrations of both hippuric acid and benzoic acid. The results show that elevating hippuric acid in the urine had a marked negative effect on both nitrification and denitrification rates and on subsequent N2 O fluxes. This study indicates the potential for developing a novel mitigation strategy based on manipulation of urine composition through ruminant diet. 相似文献
90.
GERALDINE L. TIERNEY TIMOTHY J. FAHEY PETER M. GROFFMAN† JANET P. HARDY‡ ROSS D. FITZHUGH§ CHARLES T. DRISCOLL¶ JOSEPH B. YAVITT 《Global Change Biology》2003,9(5):670-679
Understanding how exogenous and endogenous factors control the distribution, production and mortality of fine roots is fundamental to assessing the implications of global change, yet our knowledge of control over fine root dynamics remains rudimentary. To improve understanding of these processes, the present study developed regression relationships between environmental variables and fine root dynamics within a northern hardwood forest in New Hampshire, USA, which was experimentally manipulated with a snow removal treatment. Fine roots (< 1 mm diameter) were observed using minirhizotrons for 2 years in sugar maple and yellow birch stands and analyzed in relation to temperature, water and nutrient availability. Fine root dynamics at this site fluctuated seasonally, with growth and mortality peaking during warmer months. Monthly fine root production was strongly associated with mean monthly air temperature and neither soil moisture nor nutrient availability added additional predictive power to this relationship. This relationship exhibited a seasonal temperature hysteresis, which was altered by snow removal treatment. These results suggest that both exogenous and endogenous cues may be important in controlling fine root growth in this system. Proportional fine root mortality was directly associated with mean monthly soil temperature, and proportional fine root mortality during the over‐winter interval was strongly related to whether the soil froze. The strong relationship between fine root production and air temperature reported herein contrasts with findings from some hardwood forest sites and indicates that controls on fine root dynamics vary geographically. Future research must more clearly distinguish between endogenous and exogenous control over fine root dynamics in various ecosystems. 相似文献