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41.
Bacterial Ecology of Fermented Cucumber Rising pH Spoilage as Determined by Nonculture‐Based Methods 下载免费PDF全文
Eduardo Medina Ilenys M. Pérez‐Díaz Fred Breidt Janet Hayes Wendy Franco Natasha Butz María Andrea Azcarate‐Peril 《Journal of food science》2016,81(1):M121-M129
Fermented cucumber spoilage (FCS) characterized by rising pH and the appearance of manure‐ and cheese‐like aromas is a challenge of significant economical impact for the pickling industry. Previous culture‐based studies identified the yeasts Pichia manshurica and Issatchenkia occidentalis, 4 Gram‐positive bacteria, Lactobacillus buchneri, Lactobacillus parrafaraginis, Clostridium sp., and Propionibacterium and 1 Gram‐negative genus, Pectinatus, as relevant in various stages of FCS given their ability to metabolize lactic acid. It was the objective of this study to augment the current knowledge of FCS using culture‐independent methods to microbiologically characterize commercial spoilage samples. Ion Torrent data and 16S rRNA cloning library analyses of samples collected from commercial fermentation tanks confirmed the presence of L. rapi and L. buchneri and revealed the presence of additional species involved in the development of FCS such as Lactobacillus namurensis, Lactobacillus acetotolerans, Lactobacillus panis, Acetobacter peroxydans, Acetobacter aceti, and Acetobacter pasteurianus at pH below 3.4. The culture‐independent analyses also revealed the presence of species of Veillonella and Dialister in spoilage samples with pH above 4.0 and confirmed the presence of Pectinatus spp. during lactic acid degradation at the higher pH. Acetobacter spp. were successfully isolated from commercial samples collected from tanks subjected to air purging by plating on Mannitol Yeast Peptone agar. In contrast, Lactobacillus spp. were primarily identified in samples of FCS collected from tanks not subjected to air purging for more than 4 mo. Thus, it is speculated that oxygen availability may be a determining factor in the initiation of spoilage and the leading microbiota. 相似文献
42.
Three engineering treatments were implemented in a driving simulator study to assess the effect of road-based measures on alleviating the symptoms of fatigue. Using results from previous research on the effect of circadian rhythms on fatigue-related crashes, two groups of male drivers were recruited for this study: young shift workers under the age of 35, who attended immediately after their night shift, and older drivers over the age of 45, who completed the study during the ‘post lunch dip’ period, after consuming lunch. Eye tracking (PERCLOS) and lateral driver performance measures were used to assess whether baseline measures of fatigue changed after drivers experienced each of the three treatments, which included variable message signs, chevrons and rumble strips. Results showed a marked difference in these measures between drivers’ baseline (not fatigued) and experimental (fatigued) visits. There were also some reductions in lateral deviation and eye closure (as measured by PERCLOS) when the treatments were encountered, but no marked difference between the three treatments. These results suggest that in addition to driver- and vehicle-based methods currently employed to mitigate the effects of fatigue, the inclusion of such engineering measures may help alleviate fatigue-related impairments in driving, particularly if such treatments are implemented during long stretches of straight monotonous roads which are known to be associated with fatigue-related crashes. However, positive effects of the treatments were short lived, prompting the need for further investigations on their optimal frequency of presentation and combination to achieve maximum impact from these low-cost, road-based treatments. 相似文献
43.
44.
Whipple Natasha; Bernier Annie; Mageau Geneviève A. 《Canadian Metallurgical Quarterly》2011,47(2):396
The aim of this study was to examine the developmental significance of the newly developed dimensional approach to attachment state of mind by investigating its capacity to predict individual differences in the quality of two caregiving behaviors—maternal sensitivity and maternal autonomy support—that are linked to numerous important child outcomes. Seventy-one upper-middle-class, predominantly French-speaking and Caucasian dyads participated in 3 home visits (34 girls). The Adult Attachment Interview (AAI) was administered when the infants were 8 months old, maternal sensitivity was assessed when they were 12 months old, and maternal autonomy support was assessed at 15 months. The results revealed that, above and beyond SES, maternal sensitivity was negatively related to the dismissing dimension of the AAI, whereas maternal autonomy support was negatively linked to the preoccupied/unresolved dimension. In contrast, the traditional AAI categories were not significantly linked to parenting. These results speak to the relevance of using a continuous approach to attachment state of mind when predicting individual differences in specific caregiving behaviors. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
45.
Lante Carbognani Joussef Espidel Natasha Carbognani Leryn Albujas Marisol Rosquete Liakarla Parra Jennifer Mota Anita Espidel Nancy Querales 《Petroleum Science and Technology》2000,18(5):671-699
n-Heptane insoluble contents were determined for an extraheavy-oil vacuum residue, one petroleum and one coal pitch as a function of particle size. This variable was found to affect the yields of insoluble material, aspect which was also observed during extractions carried out with aromatic and halogenated solvents. The precision of results was observed to be independent on the operators. A study was carried out to determine the effect of sample drying time on fraction yields. It was found that maltene fractions were strongly dependent on this variable, whereas asphaltene fractions were totally independent
Predissolution in aromatic solvents proved worthless from the repeatability point of view. However, predissolution of the oil residue in CH2Cl2 followed by filtration and asphaltene precipitation with simultaneous solvent removal, was deemed to be a suitable technique to remove mineral matter and isolate asphaltenes in a single step
Sample oxidation during asphaltene precipitation and isolation was detected by gravimetric and spectroscopic techniques. This fact is very important since common precipitation techniques do not address this issue
Preliminary accelerated extraction experiments carried out with pitch samples at high temperature and pressure, revealed that this approach can be a very interesting research tool to investigate solubility properties. 相似文献
Predissolution in aromatic solvents proved worthless from the repeatability point of view. However, predissolution of the oil residue in CH2Cl2 followed by filtration and asphaltene precipitation with simultaneous solvent removal, was deemed to be a suitable technique to remove mineral matter and isolate asphaltenes in a single step
Sample oxidation during asphaltene precipitation and isolation was detected by gravimetric and spectroscopic techniques. This fact is very important since common precipitation techniques do not address this issue
Preliminary accelerated extraction experiments carried out with pitch samples at high temperature and pressure, revealed that this approach can be a very interesting research tool to investigate solubility properties. 相似文献
46.
Whipple Natasha; Bernier Annie; Mageau Geneviève A. 《Canadian Metallurgical Quarterly》2009,50(4):219
Understanding the intergenerational transmission of attachment patterns has been a main focus of attachment research for many years. Most of the empirical work conducted on this question has addressed maternal sensitivity to infants’ attachment needs. Given that security of attachment is defined as an attachment/exploration balance, some researchers have stressed the need to explore maternal behaviours in the context of infant exploration. The authors propose that self-determination theory (SDT) could contribute to attachment work in this respect given that it has clearly operationalized parental exploration-related behaviours and has related them to numerous child outcomes. This article highlights conceptual, empirical, and methodological parallels that can be drawn between SDT and attachment theory, thus suggesting that they could be complementary on many levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
47.
We define bisimulations for temporal logic with Since and Until. This new notion is compared to existing notions of bisimulations, and then used to develop the basic model theory of temporal logic with Since and Until. Our results concern both invariance and definability. We conclude with a brief discussion of the wider applicability of our ideas. 相似文献
48.
In this paper, the relationship between the Bezout and the set-theoretic approaches to left coprimeness is studied. It is shown that left coprimeness in the set-theoretic sense implies left coprimeness in the Bezout sense. In addition to these results, we investigate whether some properties for linear left coprime realizations carry over to the nonlinear case, for example we examine the relations between two left coprime realizations of the same system. 相似文献
49.
Social Network Sites (SNSs) rely exclusively on user-generated content to offer engaging and rewarding experience to its members. As a result, stimulating user communication and self-disclosure is vital for the sustainability of SNSs. However, considering that the SNS users are increasingly culturally diverse, motivating this audience to self-disclose requires understanding of their cultural intricacies. Yet existing research offers only limited insights into the role of culture behind the motivation of SNS users to self-disclose. Building on the privacy calculus framework, this study explores the role of two cultural dimensions ?C individualism and uncertainty avoidance ?C in self-disclosure decisions of SNS users. Survey responses of US and German Facebook members are used as the basis for our analysis. Structural equation modeling and multi-group analysis results reveal the distinct role of culture in the cognitive patterns of SNS users. The authors find that trusting beliefs play a key role in the self-disclosure decisions of users from individualistic cultures. At the same time, uncertainty avoidance determines the impact of privacy concerns. This paper contributes to the theory by rejecting the universal nature of privacy calculus processes. The findings provide for an array of managerial implications for SNS providers as they strive to encourage content creation and sharing by their heterogeneous members. 相似文献
50.