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71.
72.
A laboratory medium inoculated with 20 different Staphylococcus strains was prepared in accordance with a full factorial experimental design investigating the effect of temperature, pH, NaCl and glucose on growth. The 12 strains most suited to growth in a fermented meat environment were inoculated in sausage minces together with Pediococcus pentosaceus, incubated at 25 degrees C for 1 week and the produced aroma compounds collected. The data were analysed by multiple linear regression and partial least squares regression analysis. The results showed that increasing pH and temperature from 4.6 to 6.0 and 10 to 26 degrees C, respectively, increased growth of all strains with strong synergy between temperature and pH. Increasing salt concentration from 5% to 15% w/v decreased growth of most strains, but the effect of pH and temperature was much stronger than the effect of salt. Strains of S. carnosus were more salt tolerant than strains of S. equorum and S. xylosus, especially at high pH and temperature. Addition of glucose up to 0.5% w/v had no significant influence on growth of any of the strains. With regard to aroma production, species characteristics were detected. S. carnosus and S. xylosus were quite different regarding the overall aroma profiles, whereas the profiles of S. equorum lied somewhere in-between. Contrary to S. carnosus, S. xylosus and S. equorum did not produce 2-methyl-1-butanol. On the other hand, in particular, S. xylosus produced more 3-methyl-1-butanol. Except for one of the strains of S. equorum, S. xylosus and S. equorum formed more diacetyl, 2-butanone and acetoin and also more of the methyl-branched ketones arising from degradation of leucine, isoleucine and valine. S. carnosus produced more methyl-branched aldehydes, acids and corresponding esters from leucine, isoleucine and valine compounds that have been correlated with fermented sausage maturity in former studies. S. equorum produced the least of the methyl-branched aldehydes. 相似文献
73.
Benenson ZM Elizarov AB Yakovleva TV O'Brien WD 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2002,49(12):1665-1685
A new three-dimensional (3-D) acoustic image formation technique is proposed that is based on the transmission of wide bandwidth pulse signals and the application of the 3-D fast Fourier transform. A solution to the Helmholtz wave equation has been obtained using the Born approximation. The solution contains analytical expressions for the spatial spectra of the transmit and receive radiation patterns for transducers of various geometries with lenses of fixed focal distances. It has been shown that the proposed algorithms allow for radiation patterns with constant widths at depths both behind and in front of the focal point, starting practically from the plane of the transducer. The theoretical and experimental investigations and computer simulation for both spherical and rectangular transducer shapes have been performed. The results were used to estimate the beamwidths and the side lobe levels. A variant of the linear array has been studied for a cylindrical lens of a fixed focal distance moving in a lateral direction. It has been shown that, in this case, a high resolution (of the order of a few wavelengths) can be achieved along all three Cartesian coordinates at a very high scanning velocity. The influence of the moving scatterers' velocity in inhomogeneous medium on the spatial radiation pattern characteristics has been estimated. 相似文献
74.
75.
Tatiana Miazhynskaia Sylvia Frühwirth-Schnatter 《Computational statistics & data analysis》2006,51(3):2029-2042
Neural networks provide a tool for describing non-linearity in volatility processes of financial data and help to answer the question “how much” non-linearity is present in the data. Non-linearity is studied under three different specifications of the conditional distribution: Gaussian, Student-t and mixture of Gaussians. To rank the volatility models, a Bayesian framework is adopted to perform a Bayesian model selection within the different classes of models. In the empirical analysis, the return series of the Dow Jones Industrial Average index, FTSE 100 and NIKKEI 225 indices over a period of 16 years are studied. The results show different behavior across the three markets. In general, if a statistical model accounts for non-normality and explains most of the fat tails in the conditional distribution, then there is less need for complex non-linear specifications. 相似文献
76.
Holden Ronald R.; Wasylkiw Louise; Starzyk Katherine B.; Book Angela S.; Edwards Melanie J. 《Canadian Metallurgical Quarterly》2006,38(1):24
Four studies investigated the dimensionality of the NEO Five-Factor Inventory (NEO-FFI; P. T. Costa & R. R. McCrae, 1992). In Study 1, four inferential dimensions and four clusters represented the NEO-FFI when 114 undergraduates freely sorted items into categories. Construct validity for four item-clusters derived from the inferential space was obtained in Study 2 based on self-report with 304 undergraduates. Study 3 validated these inferential clusters using self and peer reports for 420 undergraduates. Study 4 validated the cluster scales for predicting quality of life and significant social and cultural behaviours for 110 undergraduates. Implications for implicit personality theory, the number of dimensions issue in personality, and test construction are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
77.
How can schools and parents work together more effectively? This article describes a participatory action research (PAR) project with a group of parents whose children had been classified as having emotional disabilities. As the parents shared their stories of trying to navigate the special education system, they developed critical consciousness about their experiences of stress, powerlessness, and alienation. They became mobilized and obtained information about testing, diagnostic classification, and educational options for their children. Armed with this information, they developed and implemented an action plan to improve family-school relationships at the local, community, and state levels. The article concludes with an example of how the PAR model can be exported to a variety of mental health settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
78.
Rodrigo Scherer Paula Rossini Augusti Vivian Caetano Bochi Camila Steffens Leadir Lucy Martins Fries Ana Paula Daniel Ernesto Hashime Kubota João Radünz Neto Tatiana Emanuelli 《Food chemistry》2006,99(1):136-142
The effect of two slaughter methods (immersion in ice-water slurry and electrical stunning followed by ice slurry asphyxiation) on chemical and microbiological parameters of grass carp (Ctenopharyngodon idella) stored in ice for 20 days was evaluated. No differences in total volatile basic nitrogen (TVB-N), pH, carbohydrate or protein content of mucus were observed between the slaughter methods. Ice-slaughtered fish had lower bacteria counts at the beginning of storage, but higher counts than fish slaughtered by electricity at the end of storage (p < 0.05). However, no significant differences in the shelf life were observed between the slaughter methods evaluated (limit of acceptability – counts > 3 × 106 CFU g−1 – attained after 13–16 days). Results indicated that the chemical parameters evaluated have a limited applicability to assess the shelf life of grass carp stored in ice, since pH limit (6.8) was exceeded after 4 days, while TVB-N limit (30 mg%) was not attained after 20 days of storage. 相似文献
79.
Xianmin Chang Peter G Alderson Tracey A Hollowood Louise Hewson Charles J Wright 《Journal of the science of food and agriculture》2006,86(14):i-vi
Retraction: The following article from the Journal of the Science of Food and Agriculture , ‘Temperature affects flavour intensity and quality of aroma in fresh basil (Ocimum basilicum L.) leaves’ by Xianmin Chang, Peter G Alderson, Tracey A Hollowood, Louise Hewson, and Charles J Wright, published online on 19 October 2005 in Wiley InterScience (www.interscience.wiley.com), has been retracted by agreement between the authors, the journal Editor in Chief, David S. Reid and John Wiley & Sons, Ltd. The retraction has been agreed due to overlap between this article and the following article published in the The Journal of Horticultural Science & Biotechnology ; ‘Effect of temperature integration on the growth and volatile oil content of Basil (Ocimum basilicum L.)’ by Xianmin Chang, Peter G Alderson and Charles J Wright. Volume 80 Issue 5, 2005, pages 593 – 598 相似文献
80.
Studied the development and validity of an instrument designed to measure stress by evaluating subjective feelings of stress without referring to "stress" or "stressors." Human subjects: 696 male and female Canadian adults, divided into 6 groups. Group I (15 Ss) were asked to provide a list of stress indicators for themselves, their spouses, and others. These indicators were used to establish the content validity of the Mesure de Stress Psychologique (MSP) ("Psychological State of Stress Measure"). Group II (98 university students) Ss were given a 95-item stress questionnaire; the results were analyzed statistically and used to select 74 items for the MSP. Group III (97 university students) Ss were given the 74-item MSP to determine the internal consistency of the instrument. Group IV (188 married couples with a primary school child) Ss were asked to answer the MSP for themselves and for their spouses. These results were analyzed statistically according to sex, family structure, and socioeconomic variables. Group V (66 adults aged 20–60 yrs) and Group VI (44 dental students) Ss were given a 53-item MSP on 2 to 4 occasions to evaluate test–retest and hypothetical-deductive validity. The results were evaluated using a multivariate analysis of variance (MANOVA). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献