Effects of repeated cycles of acid challenge and growth on the phenotype and virulence of Salmonella enterica

Aims: The aim of the study was to investigate how stresses like low pH, which may be encountered in farms or food preparation premises, shape populations of Salmonella enterica by the selection of stress-resistant variants. Methods and Results: Stationary-phase cultures of S. enterica serovar Enteritidis and serovar Typhimurium (one strain of each) were exposed to pH 2Æ5 for up to 4 h, followed by growth at pH 7 for 48 h. This process was repeated 15 times in two separate experiments, which increased the acid resistance of the three out of four populations we obtained, by three- to fourfold. Sustainable variants derived from the populations showed changes in colony morphology, expression of SEF17 fimbriae, growth, increased heat resistance and reduced virulence. Conclusions: The study demonstrates that low pH environments can select for populations of S. enterica with persistent phenotypic changes such as increased acid resistance and occasionally increased SEF17 expression and lower virulence. Significance and Impact of the Study: There is a common belief that increased acid resistance coincides with increased virulence. This study demonstrates for the first time that increased acid resistance often impairs virulence and affects the general phenotype of S. enterica.

The effects of word exposure frequency and elaboration of word processing on incidental L2 vocabulary acquisition through reading

Research on incidental second language (L2) vocabulary acquisition through reading has claimed that repeated encounters with unfamiliar words and the relative elaboration of processing these words facilitate word learning. However, so far both variables have been investigated in isolation. To help close this research gap, the current study investigates the differential effects of the variables ‘word exposure frequency’ and ‘elaboration of word processing’ on the initial word learning and subsequent word retention of advanced learners of L2 English. Whereas results showed equal effects for both variables on initial word learning, subsequent word retention was more contingent on elaborate processing of form–meaning relationships than on word frequency. These results, together with those of the studies reviewed, suggest that processing words again after reading (input–output cycles) is superior to reading-only tasks. The findings have significant implications for adaptation and development of teaching materials that enhance L2 vocabulary learning.

Accounting for risk aversion in repeated prisoners’ dilemma games: an experimental test

We apply experimental methods to study the role of risk aversion on players’ behavior in repeated prisoners’ dilemma games. Faced with quantitatively equal discount factors, the most risk-averse players will choose Nash strategies more often in the presence of uncertainty than when future profits are discounted in a deterministic way. Overall, we find that risk aversion relates negatively with the frequency of collusive outcomes.

Enhancing consumer liking of low salt tomato soup over repeated exposure by herb and spice seasonings

There is strong evidence for the link between high dietary sodium and increased risk of cardiovascular disease which drives the need to reduce salt content in foods. In this study, herb and spice blends were used to enhance consumer acceptability of a low salt tomato soup (0.26% w/w). Subjects (n=148) scored their liking of tomato soup samples over five consecutive days. The first and last days were pre-and post-exposure visits where all participants rated three tomato soup samples; standard, low salt and low salt with added herbs and spices. The middle 3 days were the repeated exposure phase where participants were divided into three balanced groups; consuming the standard soup, the low salt soup, or the low salt soup with added herbs and spices. Reducing salt in the tomato soup led to a significant decline in consumer acceptability, and incorporating herbs and spices did not lead to an immediate enhancement in liking. However, inclusion of herbs and spices enhanced the perception of the salty taste of the low salt soup to the same level as the standard. Repeated exposure to the herbs and spice-modified soup led to a significant increase in the overall liking and liking of flavour, texture and aftertaste of the soup, whereas no changes in liking were observed for the standard and low salt tomato soups over repeated exposure. Moreover, a positive trend in increasing the post-exposure liking of the herbs and spices soup was observed. The findings suggest that the use of herbs and spices is a useful approach to reduce salt content in foods; however, herbs and spices should be chosen carefully to complement the food as large contrasts in flavour can polarise consumer liking.

Subjective evaluation of experimental dyspnoea: effects of isocapnia and repeated exposure

Resistive respiratory loading is an established stimulus for the induction of experimental dyspnoea. In comparison to unloaded breathing, resistive loaded breathing alters end-tidal CO2 (PETCO2), which has independent physiological effects (e.g. upon cerebral blood flow). We investigated the subjective effects of resistive loaded breathing with stabilized PETCO2 (isocapnia) during manual control of inspired gases on varying baseline levels of mild hypercapnia increased PETCO2). Furthermore, to investigate whether perceptual habituation to dyspnoea stimuli occurs, the study was repeated over four experimental sessions. Isocapnic hypercapnia did not affect dyspnoea unpleasantness during resistive loading. A post hoc analysis revealed a small increase of respiratory unpleasantness during unloaded breathing at +0.6 kPa, the level that reliably induced isocapnia. We didnot observe perceptual habituation over the four sessions. We conclude that isocapnic respiratory loading allows stable induction of respiratory unpleasantness, making it a good stimulus for multi-session studies of dyspnoea.

Hydrocarbon biodegradation and soil microbial community response to repeated oil exposure

Bioremediation strategies continue to be developed to mitigate the environmental impact of petroleum hydrocarbon contamination. This study investigated the ability of soil microbiota, adapted by prior exposure, to biodegrade petroleum. Soils from Barrow Is. (W. Australia), a class A nature reserve and home to Australia’s largest onshore oil field, were exposed to Barrow production oil (50 ml/kg soil) and incubated (25 °C) for successive phases of 61 and 100 days. Controls in which oil was not added at Phase I or II were concurrently studied and all treatments were amended with the same levels of additional nutrient and water to promote microbial activity. Prior exposure resulted in accelerated biodegradation of most, but not all, hydrocarbon constituents in the production oil. Molecular biodegradation parameters measured using gas chromatography–mass spectrometry (GC–MS) showed that several aromatic constituents were degraded more slowly with increased oil history. The unique structural response of the soil microbial community was reflected by the response of different phospholipid fatty acid (PLFA) sub-classes (e.g. branched saturated fatty acids of odd or even carbon number) measured using a ratio termed Barrow PLFA ratio (B-PLFAr). The corresponding values of a previously proposed hydrocarbon degrading alteration index showed a negative correlation with hydrocarbon exposure, highlighting the site specificity of PLFA-based ratios and microbial community dynamics. B-PLFAr values increased with each Phase I and II addition of production oil. The different hydrocarbon biodegradation rates and responses of PLFA subclasses to the Barrow production oil probably relate to the relative bioavailability of production oil hydrocarbons. These different effects suggest preferred structural and functional microbial responses to anticipated contaminants may potentially be engineered by controlled pre-exposure to the same or closely related substrates. The bioremediation of soils freshly contaminated with petroleum could benefit from the addition of exhaustively bioremediated soils rich in biota primed for the impacting hydrocarbons.

Does repeated burial of skeletal muscle tissue (Ovis aries) in soil affect subsequent decomposition?

The repeated introduction of an organic resource to soil can result in its enhanced degradation. This phenomenon is of primary importance in agroecosystems, where the dynamics of repeated nutrient, pesticide, and herbicide amendment must be understood to achieve optimal yield. Although not yet investigated, the repeated introduction of cadaveric material is an important area of research in forensic science and cemetery planning. It is not currently understood what effects the repeated burial of cadaveric material has on cadaver decomposition or soil processes such as carbon mineralization. To address this gap in knowledge, we conducted a laboratory experiment using ovine (Ovis aries) skeletal muscle tissue (striated muscle used for locomotion) and three contrasting soils (brown earth, rendzina, podsol) from Great Britain. This experiment comprised two stages. In Stage I skeletal muscle tissue (150 g as 1.5 g cubes) was buried in sieved (4.6 mm) soil (10 kg dry weight) calibrated to 60% water holding capacity and allowed to decompose in the dark for 70 days at 22 °C. Control samples comprised soil without skeletal muscle tissue. In Stage II, soils were weighed (100 g dry weight at 60% WHC) into 1285 ml incubation microcosms. Half of the soils were designated for a second tissue amendment, which comprised the burial (2.5 cm) of 1.5 g cube of skeletal muscle tissue. The remaining half of the samples did not receive tissue. Thus, four treatments were used in each soil, reflecting all possible combinations of tissue burial (+) and control (−). Subsequent measures of tissue mass loss, carbon dioxide-carbon evolution, soil microbial biomass carbon, metabolic quotient and soil pH show that repeated burial of skeletal muscle tissue was associated with a significantly greater rate of decomposition in all soils. However, soil microbial biomass following repeated burial was either not significantly different (brown earth, podsol) or significantly less (rendzina) than new gravesoil. Based on these results, we conclude that enhanced decomposition of skeletal muscle tissue was most likely due to the proliferation of zymogenous soil microbes able to better use cadaveric material re-introduced to the soil.

The law of charitable uses, rev. and much enl.; with many cases in law both antient and modern: whereunto is now added,the learned reading of Sr Francis Moor, Kt. ... upon the statute of 43 Eliz. concerning charitable uses, (who was a member of that Parliament when that statute was made, and the penner thereof.) Abridged by himself, and now printed by his own original manuscript. Together, with the manner of proceedings in Chancery, by information, in the name of the King's attorney-general, for relief, on divers cases, wherein the aid of this statute is not required ... Methodically digested,

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Predicting jurors' decisions: The effects of repeated expression and forewarning in civil voir dire

To help lawyers uncover jurors' attitudes and predict verdict, litigation experts recommend that attorneys encourage jurors to repeatedly express their attitudes during voir dire. While social cognitive literature has established that repeated expression of attitudes increases accessibility and behavior predictability, the persuasive twist on the method exercised in trials deserves empirical investigation. Only one study has examined the use of repeated expression within a legal context with the results finding that the tactic increased accessibility, but did not influence the attitude verdict relationship. This dissertation reexamines the ability of civil attitudes to predict verdict in a civil trial and investigates the use of repeated expression as a persuasive tactic utilized by both parties (Plaintiff and Defense) within a civil voir dire in an attempt to increase attitudinal strength, via accessibility, and change attitudes to better predict verdict. This project also explores potential moderators, repetition by the opposing party and the use of a forewarning, to determine their ability to counter the effects of repeated expression on attitudes and verdict.^ This dissertation project asked subjects to take on the role of jurors in a civil case. During the voir dire questioning session, the number of times the participants were solicited to express their attitudes towards litigation crisis by both parties was manipulated (one vs. five). Also manipulated was the inclusion of a forewarning statement from the plaintiff, within which mock jurors were cautioned about the repeated tactics that the defense may use to influence their attitudes. Subsequently, participants engaged in a response latency task which measured the accessibility of their attitudes towards various case-related issues. After reading a vignette of a fictitious personal injury case, participants rendered verdict decisions and responded to an attitude evaluation scale. Exploratory factor analyses, Probit regressions, and path analyses were used to analyze the data. Results indicated that the act of repeated expression influenced both the accessibility and value of litigation crisis attitudes thus increasing the attitude-verdict relationship, but only when only one party engaged in it. Furthermore, the forewarning manipulation did moderate the effect of repeated expression on attitude change and verdict, supporting our hypothesis.^

Effectiveness of skills- versus metacognitive strategy-based approaches on reading comprehension of college developmental students

This study explored the relative value of behavioral and cognitive psychology as the basis of instruction for underprepared college students enrolled in developmental reading courses. Specifically this study examined the effects of a metacognitive strategy-based instructional approach (MSIA) modeling a metacognitive self-questioning technique (MSQT) versus a traditional skills-based instructional approach (SIA) on the Nelson-Denny reading comprehension scores of college developmental readers and whether there were significant differences in achievement based on instructional method used and on the sex of students. The sample consisted of 100 college developmental reading students who were enrolled in six intact sections of a reading course (REA0002). Participants completed a pretest of the comprehension subtest of the Nelson-Denny Reading Test (Form G). Three of these classes (n = 49) were taught using metacognitive-strategy instruction and three classes (n = 51) were instructed using skills-based instruction. They then received a semester of instruction intended to improve their reading comprehension. At the end of the semester, participants completed a post-test of the Nelson-Denny Reading Comprehension Test (Form H). A two (Between) x one (Within) Repeated Measures Analysis of Variance (ANOVA) was utilized to test each of the hypotheses of this study. Results showed that there were no significant differences in reading comprehension between the groups receiving the different instructional treatments and no differences in reading comprehension between the men and women participants. Based on the findings, implications for research and recommendations for future research were discussed.

The effect of a clinical practicum on elementary education preservice teachers' development of reading expertise

The purpose of the study was to measure gains in the development of elementary education teachers’ reading expertise, to determine if there was a differential gain in reading expertise, and last, to examine their perceptions of acquiring reading expertise. This research is needed in the field of teacher education, specifically in the field of reading. A quasi-experimental design with a comparison group using pretest-posttest mixed-method, repeated measures was utilized. Quantitative data analysis measured the development of reading expertise of elementary preservice teachers compared to early childhood preservice teachers; and, was used to examine the differential gains in reading expertise. A multivariate analysis of variance (MANOVA) was conducted on pre- and posttest responses on a Protocol of Questions. Further analysis was conducted on five variables (miscue analysis, fluency analysis, data analysis, inquiry orientation and intelligent action) using a univariate analysis of variance (ANOVA). A one-way ANOVA was carried out on gain scores of the low and middle groups of elementary education preservice teachers. Qualitative data analysis suggested by Merriam (1989) and Miles and Huberman (1994) was used to determine if the elementary education preservice teachers perceived they had acquired the expertise to teach reading. Elementary education preservice teachers who participated in a supervised clinical practicum made significant gains in their development of reading expertise as compared to early childhood preservice teachers who did not make significant gains. Elementary education preservice teachers who were in the low and middle third levels of expertise at pretest demonstrated significant gains in reading expertise. Last, elementary education preservice teachers perceived they had acquired the expertise to teach reading. The study concluded that reading expertise can be developed in elementary education preservice teachers through participation in a supervised clinical practicum. The findings support the idea that preservice teachers who will be teaching reading to elementary students would benefit from a supervised clinical practicum.

The relationship of culturally responsive instruction and the reading comprehension and attitude of struggling urban adolescent readers

Culturally responsive instruction refers to the identification of relevant cultural aspects of students' lives and infusion of these into the curriculum. This instructional approach assumes that a culturally appropriate curriculum can potentially motivate, engage, and lead students to higher rates of achievement. This quasi-experimental study (N=44) investigated the relationship of culturally responsive instruction and the reading comprehension and attitude of struggling urban adolescent readers. The study incorporated the use of culturally responsive instruction using culturally relevant literature (CRL), the Bluford Series Novels, as authentic texts of instruction. Participants were seventh grade reading students at a Title I middle school in South Florida. After a baseline period, two different classes were taught for 8 weeks using different methods. One class formed the experimental group ( n=22) and the other class formed the comparison group (n =22). The CRI curriculum for the experimental group embraced the socio-cultural perspective through the use of small discussion groups in which students read and constructed meaning with peers through interaction with the Bluford Series Novels; gave written responses to multiple strategies according to SCRAP - Summarize, Connect, Reflect, Ask Questions, Predict; responded to literal and inferential questions, while at the same time validating their responses through evidence from the text. The Read XL (basal reader) curriculum of the comparison group utilized a traditional form of instruction which incorporated the reading of passages followed by responses to comprehension questions, and teacher-led whole group discussion. The main sources of data were collected from the Gates-MacGinitie Reading Tests, the Florida Assessments for Instruction in Reading (FAIR), and the Rhody Secondary Reading Attitude Assessment. Statistical analyses were performed using Repeated Measures ANOVAs. Findings from the study revealed that the experimental participants' reading attitudes and FAIR comprehension scores increased when compared to the comparison group. Overall, the results from the study revealed that culturally responsive instruction can potentially foster reading comprehension and a more positive attitude towards reading. However, a replication of this study in other settings with a larger, more randomized sample size and a greater ethnic variation is needed in order to make full generalizations.

The Relationship of Culturally Responsive Instruction and the Reading Comprehension and Attitude of Struggling Urban Adolescent Readers

Culturally responsive instruction refers to the identification of relevant cultural aspects of students’ lives and infusion of these into the curriculum. This instructional approach assumes that a culturally appropriate curriculum can potentially motivate, engage, and lead students to higher rates of achievement. This quasi-experimental study (N=44) investigated the relationship of culturally responsive instruction and the reading comprehension and attitude of struggling urban adolescent readers. The study incorporated the use of culturally responsive instruction using culturally relevant literature (CRL), the Bluford Series Novels, as authentic texts of instruction. Participants were seventh grade reading students at a Title I middle school in South Florida. After a baseline period, two different classes were taught for 8 weeks using different methods. One class formed the experimental group (n=22) and the other class formed the comparison group (n=22). The CRI curriculum for the experimental group embraced the socio-cultural perspective through the use of small discussion groups in which students read and constructed meaning with peers through interaction with the Bluford Series Novels; gave written responses to multiple strategies according to SCRAP – Summarize, Connect, Reflect, Ask Questions, Predict; responded to literal and inferential questions, while at the same time validating their responses through evidence from the text. The Read XL (basal reader) curriculum of the comparison group utilized a traditional form of instruction which incorporated the reading of passages followed by responses to comprehension questions, and teacher-led whole group discussion. The main sources of data were collected from the Gates-MacGinitie Reading Tests, the Florida Assessments for Instruction in Reading (FAIR), and the Rhody Secondary Reading Attitude Assessment. Statistical analyses were performed using Repeated Measures ANOVAs. Findings from the study revealed that the experimental participants’ reading attitudes and FAIR comprehension scores increased when compared to the comparison group. Overall, the results from the study revealed that culturally responsive instruction can potentially foster reading comprehension and a more positive attitude towards reading. However, a replication of this study in other settings with a larger, more randomized sample size and a greater ethnic variation is needed in order to make full generalizations.

The ILC's Articles on Responsibility of States for Internationally Wrongful Acts: Completion of the Second Reading

In 2001 the International Law Commission finally adopted on second reading the Draft Articles on Responsibility of States for Internationally Wrongful Acts with commentaries, bringing to an end nearly 50 years of ILC work on the subject. This article reviews the final group of changes to the text, focusing on the definitions of ‘injury’ and ‘damage’, assurances of non‐repetition in the light of the LaGrand case, procedural aspects of countermeasures and the controversy over measures taken in response to a breach by states which are not individually injured. The focus of debate now turns to the UNGA Sixth Committee, which will have to decide what to make of the Draft Articles. The ILC itself recommended an initial resolution taking note of the Articles, with subsequent consideration (after a period of years) of a possible diplomatic conference with a view to concluding a convention. This modest proposal allows for further reflection on the text and may help to avoid possibly divisive and inconclusive debate in the Sixth Committee. At the same time it allows time for better understanding of the many changes made as compared with the first reading text (1996).