1,890 research outputs found
Guest Editors' introduction: philosophical contributions to leadership ethics
This article introduces the first of two special issues on philosophical approaches to leadership ethics. In it, we show some of the ways that philosophy contributes to the study of leadership and leadership ethics. We begin with an overview of how philosophers have treated some of the ethical aspects and challenges of leadership. These include discussions of self interest, the problem of dirty hands, responsibility, moral luck, power, gender and diversity, and spirituality. The articles in this issue draw on philosophy to explore a variety of ethical questions related to leadership and the relationships that leaders have with followers and others
GLUCOCORTICOID-INDUCED ALTERATION OF THE SURFACE MEMBRANE OF CULTURED HEPATOMA CELLS
Glucocorticoids induce an alteration of the surface of hepatoma tissue culture (HTC) cells as expressed by changes in cell electrophoretic, antigenic, and adhesive properties. The alteration is assayed by the increased adhesiveness of induced cells for a glass surface. The induction process has a lag period of about 3 hr and attains a plateau level after 24ā30 hr when 50ā80% of the steroid-treated cells are firmly adhered. Less than 10% of untreated cells adhere under the same conditions. Induction is inhibited by actinomycin D and cycloheximide, demonstrates both pH and temperature dependence, and responds to changes in steroid concentration and structure. By contrast, the attachment per se of preinduced cells is not affected by inhibitors of RNA and protein synthesis, fluctuations of temperature and pH, and the presence or absence of the hormone. When the induction process is reversed by removal of steroid or addition of actinomycin D, preinduced adhesiveness is lost with a half-life of 13ā24 hr, but in the presence of cycloheximide the loss is accelerated (t1/2 3ā5.5 hr). These results suggest that glucocorticoids induce the biosynthesis of a protein which either modifies the cell surface (an enzyme) or is incorporated into surface structures (structural protein)
Climate of origin affects tick (Ixodes ricinus) host-seeking behavior in response to temperature: implications for resilience to climate change?
Climate warming is changing distributions and phenologies of many organisms and may also impact on vectors of diseaseācausing pathogens. In Europe, the tick Ixodes ricinus is the primary vector of medically important pathogens (e.g., Borrelia burgdorferi sensu lato, the causative agent of Lyme borreliosis). How might climate change affect I. ricinus hostāseeking behavior (questing)? We hypothesize that, in order to maximize survival, I. ricinus have adapted their questing in response to temperature in accordance with local climates. We predicted that ticks from cooler climates quest at cooler temperatures than those from warmer climates. This would suggest that I. ricinus can adapt and therefore have the potential to be resilient to climate change. I. ricinus were collected from a cline of climates using a latitudinal gradient (northeast Scotland, North Wales, South England, and central France). Under laboratory conditions, ticks were subjected to temperature increases of 1Ā°C per day, from 6 to 15Ā°C. The proportion of ticks questing was recorded five times per temperature (i.e., per day). The theoretical potential to quest was then estimated for each population over the year for future climate change projections. As predicted, more ticks from cooler climates quested at lower temperatures than did ticks from warmer climates. The proportion of ticks questing was strongly associated with key climate parameters from each location. Our projections, based on temperature alone, suggested that populations could advance their activity season by a month under climate change, which has implications for exposure periods of hosts to tickāborne pathogens. Our findings suggest that I. ricinus have adapted their behavior in response to climate, implying some potential to adapt to climate change. Predictive models of I. ricinus dynamics and disease risk over continental scales would benefit from knowledge of these differences between populations
Maternal micronutrient status and decreased growth of Zambian infants born during and after the maize price increases resulting from the southern African drought of 2001-2002.
OBJECTIVE: To investigate the effects on maternal micronutrient status and infant growth of the increased maize prices that resulted from the southern African drought of 2001-2002. DESIGN: Longitudinal cohort study. SETTING: A maternal and child health clinic in Lusaka, Zambia. SUBJECTS: Maternal and infant health and nutrition data and maternal plasma were being collected for a study of breast-feeding and postpartum health. Samples and data were analysed according to whether they were collected before (June to December 2001), during (January 2002 to April 2003) or after (May 2003 to January 2004) the period of increased maize price. Season and maternal HIV status were controlled for in analyses. RESULTS: Maize price increases were associated with decreased maternal plasma vitamin A during pregnancy (P = 0.028) and vitamin E postpartum (P = 0.042), with the lowest values among samples collected after May 2003 (vitamin A: 0.96 micromol l(-1), 95% confidence interval (CI) 0.84-1.09, n = 38; vitamin E: 30.8 micromol mmol(-1) triglycerides, 95% CI 27.2-34.8, n = 64) compared with before January 2002 (vitamin A: 1.03 micromol l(-1), 95% CI 0.93-1.12, n = 104; vitamin E: 38.9 micromol mmol(-1) triglycerides, 95% CI 34.5-43.8, n = 47). There were no significant effects of sampling date on maternal weight, haemoglobin or acute-phase proteins and only marginal effects on infant weight. Infant length at 6 and 16 weeks of age decreased progressively throughout the study (P-values for time of data collection were 0.51 at birth, 0.051 at 6 weeks and 0.026 at 16 weeks). CONCLUSIONS: The results show modest effects of the maize price increases on maternal micronutrient status. The most serious consequence of the price increases is likely to be the increased stunting among infants whose mothers experienced high maize prices while pregnant. During periods of food shortages it might be advisable to provide micronutrient supplements even to those who are less food-insecure
Experimental Resonance Enhanced Multiphoton Ionization (REMPI) studies of small molecules
Resonance enhanced multiphoton ionization (REMPI) utilizes tunable dye lasers to ionize an atom or molecule by first preparing an excited state by multiphoton absorption and then ionizing that state before it can decay. This process is highly selective with respect to both the initial and resonant intermediate states of the target, and it can be extremely sensitive. In addition, the products of the REMPI process can be detected as needed by analyzing the resulting electrons, ions, fluorescence, or by additional REMPI. This points to a number of exciting opportunities for both basic and applied science. On the applied side, REMPI has great potential as an ultrasensitive, highly selective detector for trace, reactive, or transient species. On the basic side, REMPI affords an unprecedented means of exploring excited state physics and chemistry at the quantum-state-specific level. An overview of current studies of excited molecular states is given to illustrate the principles and prospects of REMPI
Towards an evolutionary understanding of questing behaviour in the tick Ixodes ricinus
The tick Ixodes ricinus finds its hosts by climbing vegetation and adopting a sit-and-wait tactic. This āquestingā behaviour is known to be temperature-dependent, such that questing increases with temperature up to a point where the vapor pressure deficit (drying effect) forces ticks down to rehydrate in the soil or mat layer. Little if any attention has been paid to understanding the questing of ticks from an evolutionary perspective. Here we ask whether populations from colder climatic conditions respond differently in terms of the threshold temperature for questing and the rate of response to a fixed temperature. We find significant variation between populations in the temperature sensitivity of questing, with populations from cooler climates starting questing at lower temperatures than populations from warmer temperatures. Cool climate populations also quest sooner when the temperature is held constant. These patterns are consistent with local adaptation to temperature either through direct selection or acclimation and challenge the use of fixed thresholds for questing in modeling the spread of tick populations. Our results also show how both time and temperature play a role in questing, but we are unable to explain the relationship in terms of degree-time used to model Arthropod development. We find that questing in response to temperature fits well with a quantitative genetic model of the conditional strategy, which reveals how selection on questing may operate and hence may be of value in understanding the evolutionary ecology of questing
Predictors of Long-Term Visual Outcome in Intermediate Uveitis
PURPOSE: To describe factors that predict visual loss and complications in intermediate uveitis.
DESIGN:
Cross-sectional study.
PARTICIPANTS:
Subjects with intermediate uveitis were identified from a database of 1254 uveitis patients seen in the clinic of a single consultant (S.L.L.) between 2011 and 2013.
S
METHODS:
Information was gathered from the clinical notes of all subjects examined in clinic.
MAIN OUTCOME MEASURES:
Best-corrected visual acuity (BCVA), moderate visual loss (MVL; ā¤20/50), severe visual loss (SVL; ā¤20/200).
RESULTS:
Three hundred and five subjects (550 eyes) were included in the study, comprising 24.3% of subjects seen in clinic. Mean (Ā± standard deviation) age at diagnosis was 40.9Ā±16.9 years, and 64.6% of subjects were female. Median follow-up was 8.2 years (mean, 9.7 years, 5452 eye-years). Systemic diagnosis was made in 36.1% of patients, with sarcoidosis (22.6%) and multiple sclerosis (4.6%) the most frequent systemic associations. Median BCVA was 20/30 (mean logarithm of the minimum angle of resolution [logMAR] 0.26Ā±0.38, n = 550 eyes) at presentation, 20/30 (mean logMAR 0.22Ā±0.42, n = 430) at 5 years, and 20/30 (mean logMAR 0.23Ā±0.46, n = 260) at 10 years. Macular edema was observed in 224 eyes (40.7%) and was associated with idiopathic disease (P = 0.001) and diabetes (P = 0.001). Topical therapy was used in 82.7%, and 34.2% received local injections of corticosteroids. A total of 50.5% required oral steroids and 13.8% required second-line immunosuppression. Subjects with a diagnosis of sarcoidosis were less likely to require a second-line agent (4.3% vs. 16.2%, P = 0.011). On multivariate analysis, visual acuity at referral, retinal pigment epithelial atrophy, and macular scarring were associated with increased risk of MVL; and visual acuity at referral, local therapy, macular scarring, retinal detachment, and hypotony and phthisis were associated with increased risk of SVL.
CONCLUSIONS:
Intermediate uveitis has a long disease course with frequent complications and often requires systemic treatment. Despite this, most subjects are still able to achieve good long-term visual outcomes
Rhizobium radiobacter Endophthalmitis following Intravitreal Ranibizumab Injection.
We present the first reported case of acute endophthalmitis due to Rhizobium radiobacter after an intravitreal injection of ranibizumab for neovascular age-related macular degeneration
Perceptions of Well-Being Among Rural Nebraskans
Nebraskaās economy has been relatively stable during the past year. However, some rural areas continue to be economically challenged. How do rural Nebraskans perceive their quality of life? Do their perceptions differ by community size, the region in which they live, or their occupation? This report details 2,482 responses to the 2006 Nebraska Rural Poll, the eleventh annual effort to understand rural Nebraskansā perceptions. Respondents were asked a series of questions regarding their individual well-being. Trends for these questions are examined by comparing data from the ten previous polls to this yearās results. In addition, comparisons are made among different respondent subgroups, that is, comparisons by age, occupation, region, etc. Based on these analyses, some key findings emerged: ā¢ More rural Nebraskans report being satisfied with their job opportunities this year as compared to previous years. After reaching a low of 34 percent in 2004, the proportion satisfied with their job opportunities increased to 42 percent this year (the highest proportion in all 11 years). (page 5) ā¢ Persons with the highest household incomes are more likely than persons with lower incomes to feel they are better off compared to five years ago, are better off compared to their parents when they were their age, and will be better off ten years from now. For example, 52 percent of respondents with household incomes of 20,000 believe they will be better off ten years from now. (page 6) ā¢ More rural Nebraskans believe people are powerless to control their own lives this year as compared to past years. The proportion that either strongly agree or agree with the statement that people are powerless to control their own lives each year has averaged about 34 percent. The proportion agreeing with the statement increased slightly, to 38 percent this year, which matches the highest proportion in the 11 years of the Poll (1997 and 1999 were the other two years). (page 4) ā¢ Persons with lower education levels are more likely than persons with more education to believe that people are powerless to control their own lives. Forty-six percent of persons with a high school diploma or less education agree that people are powerless to control their own lives. However, only 25 percent of persons with a four-year college degree share this opinion. (page 9) ā¢ Rural Nebraskans continue to be generally positive about their current situation. Except in 2003, each year the proportion of rural Nebraskans that say they are better off than they were five years ago has been greater than the proportion saying they are worse off than they were five years ago. Approximately 36 percent each year have reported that they were better off than they were five years ago. This year, 35 percent believe they are better off then they were five years ago and 21 percent think they are worse off. (page 2) ā¢ Similarly, rural Nebraskans continue to be generally positive about their future. The proportion that say they will be better off ten years from now has always been greater than the proportion saying they will be worse off ten years from now (although the two were virtually identical in 1996). The proportion stating they will be better off ten years from now has generally remained about 36 percent. This year, the proportion was 34 percent. Twenty-one percent believe they will be worse off ten years from now. (page 3) ā¢ Following trends in previous years, rural Nebraskans are most satisfied with their marriage, family, friends, religion/spirituality and the outdoors. They continue to be less satisfied with job opportunities, current income level and financial security during retirement. (page 5
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