Towards an understanding of Ethical Dilemmas Faced by School Leaders

The field of ethics has attracted increasing interest in educational contexts in recent times and one reason for this heightened interest is the more complex operational milieu (Grace in Campbell 1997, p.223) in which leaders are now working. In the current climate, it is likely that educational leaders could find themselves confronted with ethical dilemmas which require a choice among competing sets of principles, values, beliefs and perspectives. This paper reports on a model for conceptualising ethical dilemmas. To illustrate the application of the model in practice, we provide a scenario and a commentary based on that scenario using the model for analysis

Description and Evaluation of Institutions Involved in Water Allocation and Distribution in Utah

Water development and allocation have been among the most important problems Utah has had to face throughout the past 117 years of development . When Utah\u27s first white settlers, the Mormon pioneers, entered Salt Lake Valley in July of 1847, little met their eyes to entice their stay. The earth was so parched and dry that they were unable to scratch the surface with their plows. Less than two hours after their arrival members of the party began digging ditches and building dams to irrigate and soften the earth so they could begin plowing

Electronic Cigarettes: Puffing Topography and Self-titration - the Importance of Nicotine Concentration, User Experience and Device Characteristics

Background: Although well documented in tobacco smokers, there is little empirical evidence on self-titration (i.e. adjusting puffing patterns to obtain desired blood nicotine levels) in e-cigarette users. The primary aim was to explore the inter-relationships between e-cigarette puffing topography, nicotine concentrations and e-cigarette characteristics. Other aims were to identify the possible predictors of smoking cessation in smokers attempting to quit using an e-cigarette. Methods: Study 1 (N = 12 experienced e-cigarette users) employed a within-participants design and measured how puffing topography differs between high (24 mg/mL) and low (6 mg/mL) nicotine concentrations in 2 separate ad lib vaping sessions. Study 2 used a mixed-participants design in which e-cigarette naïve smokers (N = 70; 62.9% female) were randomly allocated to a cigalike (18mg/mL) or a tank containing either 18 or 6 mg/mL nicotine concentrations to obtain profiles of puffing topography characteristics associated with each of the aforementioned conditions and how these evolve over a 2-week period (in 3 separate 20-minute ad lib vaping sessions). Puff duration, number and inter-puff intervals (IPI) were recorded along with exhaled carbon monoxide (CO), cigarette dependence, craving and withdrawal, and subjective effects at each session. Participants were given the e-cigarette to take home and asked to record cigarettes smoked per day (CPD) and subjective symptoms. In Study 3, Study 2 participants were followed up at 1, 3 and 6 months. Logistic regression analyses explored whether device type, nicotine concentrations, craving reduction, mean puff duration, cigarette dependence and motivation to quit could predict cessation. Results: Study 1: Liquid consumption and puff number were higher and puff duration longer in the low nicotine concentrations condition (all ps < 0.01). There were no statistically significant differences between conditions in self-reported craving, withdrawal symptoms, satisfaction, hit or adverse effects. Nicotine plasma levels was significantly higher in the high nicotine concentration condition. Study 2: Puff duration significantly increased one week post e-cigarette initiation whilst puff numbers and IPI decreased. Cigalikes were associated with longer puff duration, shorter IPI and greater number of puffs; the use of Tank 18 led to longer IPI and shorter puff duration but this was not statistically significant when compared to Tank 6. The Tank 18 and cigalikes were more efficient in reducing craving compared to the Tank 6 at baseline. Participants rated both Tanks (18 and 6 mg/mL) as more satisfying at baseline and Time 1 compared with the cigalike. CPD, CO and nicotine dependence reduced significantly at week 1 then plateaued between week 1 and 2, but did not differ between conditions. Study 3: Lower cigarette dependence, greater craving reduction with e-cigarette use reported at baseline and reports of tank use at follow up were significant predictors of cessation at 1, 3 and 6 months respectively. Nicotine concentrations, mean puff duration and motivation to quit at baseline were not significant predictors. Conclusion: Consistent with the self-titration theory, e-cigarette users engaged in compensatory puffing with lower (6 mg/mL) nicotine concentration liquids, nearly doubling their consumption. Although self-titration was incomplete with significantly higher plasma nicotine levels in the high condition, compensatory puffing was sufficient to reduce craving and withdrawal discomfort. The rapid adjustment in puffing topography and the more erratic puffing regimen in the cigalike condition both lend support to the self-titration theory. Whilst higher nicotine concentrations are more effective in reducing craving, tank systems are preferable in achieving satisfaction. This suggests an important role for device type in providing satisfaction and equally important role for nicotine concentrations to reduce craving. Delineating the mechanisms by which device types play a role in providing satisfaction and its subtle difference with craving should be one area to concentrate for future research. Those with lower cigarette dependent scores were more likely to quit at 1 month, whilst those who reported greater craving reduction following e-cigarette use in the lab were more likely to have quit at 3 months; the predictive utility of measures of craving reduction at first use can be fostered to inform smoking cessation programmes. The odds of quitting at 6 months were higher for those using a tank device at the time of follow-up compared to those using a cigalike, which is in line with previous studies suggesting that tank systems are associated with greater likelihood of successful cessation. Key findings suggest that e-cigarettes have good potential in helping reduce tobacco smoking

The effect of treatment on pathogen virulence.

The optimal virulence of a pathogen is determined by a trade-off between maximizing the rate of transmission and maximizing the duration of infectivity. Treatment measures such as curative therapy and case isolation exert selective pressure by reducing the duration of infectivity, reducing the value of duration-increasing strategies to the pathogen and favoring pathogen strategies that maximize the rate of transmission. We extend the trade-off models of previous authors, and represents the reproduction number of the pathogen as a function of the transmissibility, host contact rate, disease-induced mortality, recovery rate, and treatment rate, each of which may be influenced by the virulence. We find that when virulence is subject to a transmissibility-mortality trade-off, treatment can lead to an increase in optimal virulence, but that in other scenarios (such as the activity-recovery trade-off) treatment decreases the optimal virulence. Paradoxically, when levels of treatment rise with pathogen virulence, increasing control efforts may raise predicted levels of optimal virulence. Thus we show that conflict can arise between the epidemiological benefits of treatment and the evolutionary risks of heightened virulence

QCD traveling waves at non-asymptotic energies

Using consistent truncations of the BFKL kernel, we derive analytical traveling-wave solutions of the Balitsky-Kovchegov saturation equation for both fixed and running coupling. A universal parametrization of the ``interior'' of the wave front is obtained and compares well with numerical simulations of the original Balitsky-Kovchegov equation, even at non-asymptotic energies. Using this universal parametrization, we find evidence for a traveling-wave pattern of the dipole amplitude determined from the gluon distribution extracted from deep inelastic scattering data.Comment: 10 pages, 5 figures, minor revision, version to appear in PL

Nicotine absorption from e-cigarettes over 12 months

Background Research indicates that, over time, exclusive e-cigarette users (vapers) gradually reduce the nicotine concentration in their e-liquid and transition to more sophisticated devices. Alongside this, consumption of e-liquid increases and constant cotinine levels are maintained. Aims We aimed to confirm these observations in 27 experienced vapers tested at baseline and 12 months later, by measuring nicotine absorption (via salivary levels of the nicotine metabolite cotinine; ng/mL), nicotine concentrations in e-liquid (mg/mL), volume of e-liquid consumed (mL per day), device types and flavours used, both at baseline and 12 months. Results Vapers reduced both their nicotine concentrations in e-liquid over 12 months (from 13.83 mg/mL at baseline to 9.91 at follow up) but significantly increased their e-liquid consumption (from 4.44 to 6.84 mL). No significant changes in salivary cotinine concentrations (370.88 ng/mL at baseline and 415.78 ng/mL at follow up) were observed. There was an increase in sub-ohming (using an atomiser coil with resistance of <1 Ω with increased power) at 12 months, and in the use of fruit flavoured e-liquids. Conclusions Our sample of experienced vapers reduced the concentration of nicotine in their e-liquid over time, but maintained their nicotine intake possibly through self-titration via more intensive puffing. Findings suggest there may be little benefit in reducing nicotine e-liquid concentration since this appears to result in higher e-liquid consumption which may incur both a financial and health cost. Gaining an understanding of underlying reasons for lowering e-liquid concentration would be a useful line of empirical enquiry

Optimal designs for full and partial likelihood information — With application to survival models

Time-to-event data are often modelled through Cox’s proportional hazards model for which inference is based on the partial likelihood function. We derive a general expression for the asymptotic covariance matrix of Cox’s partial likelihood estimator for the covariate coefficients. Our approach is illustrated through an application to the special case of only one covariate, for which we construct minimum variance designs for different censoring mechanisms and both binary and interval design spaces. We compare these designs with the corresponding ones found using the full likelihood approach and demonstrate that the latter designs are highly efficient also for partial likelihood estimation

Induced antiferromagnetism and large magnetoresistances in RuSr2(Nd,Y,Ce)2Cu2O10-d ruthenocuprates

RuSr2(Nd,Y,Ce)2Cu2O10-d ruthenocuprates have been studied by neutron diffraction, magnetotransport and magnetisation measurements and the electronic phase diagram is reported. Separate Ru and Cu spin ordering transitions are observed, with spontaneous Cu antiferromagnetic order for low hole doping levels p, and a distinct, induced-antiferromagnetic Cu spin phase in the 0.02 < p < 0.06 pseudogap region. This ordering gives rise to large negative magnetoresistances which vary systematically with p in the RuSr2Nd1.8-xY0.2CexCu2O10-d series. A collapse of the magnetoresistance (MR) and magnetisation in the pre-superconducting region may signify the onset of superconducting fluctuations.Comment: 22 pages, 11 figure

Self-titration by experienced e-cigarette users: blood nicotine delivery and subjective effects (Study Data)

This is a UK laboratory study of twelve experienced e-cigarette users (11 males; 1 female; note the female participant’s data was removed from all analyses in the published paper) to understand the effects of e-liquid nicotine concentration on puffing patterns, plasma nicotine levels and subjective effects. All participants completed two vaping sessions under low (6 mg/mL) and high (24 mg/mL) nicotine e-liquid concentrations in two separate (counterbalanced) sessions at the University of East London (UEL). The data include puffing patterns (puff number, puff duration, volume of e-liquid consumed), plasma nicotine levels, craving and withdrawal symptoms after 10, 30 and 60 minutes of ad libitum vaping and self-reported positive and negative effects at 60 minutes

Development and Testing of Relative Risk-based Health Messages for Electronic Cigarette Products

Background: Health messages on e-cigarette packs emphasise nicotine addiction or harms using similar wording to warnings on cigarette packs. These may not be appropriate for e-cigarettes which constitute a reduced risk alternative for smokers. This research aimed to i) develop and test a selection of relative risk messages for e-cigarette products; ii) compare these to the two current EU Tobacco Products Directive (TPD) nicotine addiction messages; and iii) explore differences between smokers, non-smokers and dual users. Method: Twenty-six messages focusing on either harm-reduction or cessation were developed and rated by multidisciplinary experts for accuracy, persuasiveness and clarity. The eight highest ranking messages were compared alongside the TPD messages in a sample of 983 European residents (316 smokers, 327 non-smokers, 340 dual users) on understandability, believability and convincingness. Results: On all three constructs combined, the two TPD messages rated the highest, closely followed by four relative risk messages “Completely switching to e-cigarettes lowers your risk of smoking related diseases”, “Use of this product is much less harmful than smoking”, “Completely switching to e-cigarettes is a healthier alternative to smoking”, and “This product presents substantially lower risks to health than cigarettes” which did not differ statistically from the TPD messages. Non-smokers rated TPD1 significantly higher overall than dual users. Dual users rated “This product is a safer alternative to smoking” significantly higher than non-smokers. Messages did not differ on understandability. Conclusions: These alternative messages provide a useful resource for future research and for policy makers considering updating e-cigarette product labelling