139 research outputs found
Factors influencing the seasonal changes in primary productivity of the photosynthetic bacteria of Crawford Lake, Ontario
A naturally occurring population of photosynthetic bacteria,
located in the meromictic Crawford Lake, was examined during two
field seasons (1979-1981). Primary production, biomass, light
intensity, lake transparency, pH and bicarbonate concentration were
all monitored during this period at selected time intervals.
Analysis of the data indicated that (l4C) bacterial photosynthesis
was potentially limited by the ambient bicarbonate
concentration. Once a threshold value (of 270 mg/l) was reached a
dramatic (2 to 10 fold) increase in the primary productivity of the
bacteria was observed. Light intensity appeared to have very little
effect on the primary productivity of the bacteria, even at times
when analyses by Parkin and Brock (1980a) suggested that light
intensity could be limiting (i.e., 3.0-5.0 ft. candles). Shifts
in the absorption maxima at 430 nrn of the .bacteriochlorophyll
spectrum suggested that changes in the species or strain
composition of the photosynthetic bacteria had occurred during the
summer months. It was speculated that these changes might reflect
seasonal variation in the wavelength of light reaching the bacteria.
Chemocline erosion did not have the same effect on the population
size (biomass) of the photosynthetic bacteria in Crawford Lake
(this thesis) as it did in Pink Lake (Dickman, 1979). In Crawford
Lake the depth of the chemocline was lowered with no apparent loss
in biomass (according to bacteriochlorophyll data). A reverse
current was. proposed to explain the observation.
The photosynthetic bacteria contributed a significant
proportion (10-60%) of the lake1s primary productivitya Direct
evidence was obtained with (14C) labelling of the photosynthetic
bacteria, indica.ting that the zooplankton were grazing the photosynthetic
bacteria. This indicated that some of the photosynthetic
bacterial productivity was assimilated into the food chain of the
lake. Therefore, it was concluded that the photosynthetic bacteria
made a significant contribution to the total productivity of
Crawford Lake
Comparative Judgement Modeling to Map Forced Marriage at Local Levels
Forcing someone into marriage against their will is a violation of their
human rights. In 2021, the county of Nottinghamshire, UK, launched a strategy
to tackle forced marriage and violence against women and girls. However,
accessing information about where victims are located in the county could
compromise their safety, so it is not possible to develop interventions for
different areas of the county. Comparative judgement studies offer a way to map
the risk of human rights abuses without collecting data that could compromise
victim safety. Current methods require studies to have a large number of
participants, so we develop a comparative judgement model that provides a more
flexible spatial modelling structure and a mechanism to schedule comparisons
more effectively. The methods reduce the data collection burden on participants
and make a comparative judgement study feasible with a small number of
participants. Underpinning these methods is a latent variable representation
that improves on the scalability of previous comparative judgement models. We
use these methods to map the risk of forced marriage across Nottinghamshire
thereby supporting the county's strategy for tackling violence against women
and girls.Comment: Submitted. 31 pages, 8 figure
Interdisciplinary content, contestations of knowledge and informational transparency in engineering curriculum
This article is an Accepted Manuscript of an article published by Taylor & Francis Group in Teaching in Higher Education, available online at: http://www.tandfonline.com/doi/abs/10.1080/13562517.2013.836089With the introduction of key information sets (KIS) for all university programmes in the UK from 2012, the character, content and delivery of university degrees may be increasingly used by potential students to differentiate between degree programmes. Therefore, developments in curricula and the relationship to the profession are of growing importance. In this paper, we explore the role of programme content in prospective studentsâ decision-making and describe the prevalence of interdisciplinary content in civil engineering curricula. Following this, we detail student perceptions of interdisciplinary content. It is found that universities currently operate a varied approach to transparency regarding curriculum; students pay little attention to programme content before embarking on their chosen degree; and engineering students view interdisciplinary content in the curriculum with ambivalence, usually ascribing its necessity in the preparation for post-university employmen
That was a great commercial, but what were they selling?: Effects of violence and sex on memory for products in televisioncommercials
College students (N = 324) watched a television program containing violence, sex, or no violence or sex. Each program contained 3 violent ads, 3 sexual ads, and 3 neutral ads. Participants were less likely to remember the advertised brands when the ads were embedded in a violent or sexual program than when the ads were embedded in a neutral program. Violent ads were the least memorable. This memory impairment occurred for both males and females, regardless of the content of the ads. If advertisers want viewers to remember advertised brands, they should think twice about sponsoring programs containing violence and sex. © 2007 Copyright the Authors; Journal compilation © 2007 Blackwell Publishing, Inc
Secondary electron emissionâcapacitive probes for plasma potential measurements in plasmas with hot electrons
An Analysis of Vascular Access Thrombosis Events From the Proactive IV irOn Therapy in hemodiALysis Patients Trial
INTRODUCTION:
Treatment of anemia in dialysis patients has been associated with increased risk of vascular access thrombosis (VAT). Proactive IV irOn Therapy in hemodiALysis Patients (PIVOTAL) was a clinical trial of proactive compared with reactive i.v. iron therapy in patients requiring hemodialysis. We analyzed the trial data to determine whether randomized treatment arm, alongside other clinical and laboratory variables, independently associated with VAT.
METHODS:
In PIVOTAL, 2141 adult patients were randomized. The type of vascular access (arteriovenous fistula [AVF], arteriovenous graft [AVG], or central venous catheter [CVC]) was recorded at baseline and every month after randomization. The associations between clinical and laboratory data and first VAT were evaluated in a multivariate analysis.
RESULTS:
A total of 480 (22.4%) participants experienced VAT in a median of 2.1 years of follow-up. In multivariable analyses, treatment arm (proactive vs. reactive) was not an independent predictor of VAT (hazard ratio [HR] 1.13, P = 0.18). Diabetic kidney disease (HR 1.45, P < 0.001), AVG use (HR 2.29, P < 0.001), digoxin use (HR 2.48, P < 0.001), diuretic use (HR 1.25, P = 0.02), female sex (HR 1.33, P = 0.002), and previous/current smoker (HR 1.47, P = 0.004) were independently associated with a higher risk of VAT. Angiotensin receptor blocker (ARB) use (HR 0.66, P = 0.01) was independently associated with a lower risk of VAT.
CONCLUSION:
In PIVOTAL, VAT occurred in nearly 1 quarter of participants in a median of just >2 years. In this post hoc analysis, randomization to proactive i.v. iron treatment arms did not increase the risk of VAT
Basic science232.âCertolizumab pegol prevents pro-inflammatory alterations in endothelial cell function
Background: Cardiovascular disease is a major comorbidity of rheumatoid arthritis (RA) and a leading cause of death. Chronic systemic inflammation involving tumour necrosis factor alpha (TNF) could contribute to endothelial activation and atherogenesis. A number of anti-TNF therapies are in current use for the treatment of RA, including certolizumab pegol (CZP), (Cimzia Âź; UCB, Belgium). Anti-TNF therapy has been associated with reduced clinical cardiovascular disease risk and ameliorated vascular function in RA patients. However, the specific effects of TNF inhibitors on endothelial cell function are largely unknown. Our aim was to investigate the mechanisms underpinning CZP effects on TNF-activated human endothelial cells. Methods: Human aortic endothelial cells (HAoECs) were cultured in vitro and exposed to a) TNF alone, b) TNF plus CZP, or c) neither agent. Microarray analysis was used to examine the transcriptional profile of cells treated for 6 hrs and quantitative polymerase chain reaction (qPCR) analysed gene expression at 1, 3, 6 and 24 hrs. NF-ÎșB localization and IÎșB degradation were investigated using immunocytochemistry, high content analysis and western blotting. Flow cytometry was conducted to detect microparticle release from HAoECs. Results: Transcriptional profiling revealed that while TNF alone had strong effects on endothelial gene expression, TNF and CZP in combination produced a global gene expression pattern similar to untreated control. The two most highly up-regulated genes in response to TNF treatment were adhesion molecules E-selectin and VCAM-1 (q 0.2 compared to control; p > 0.05 compared to TNF alone). The NF-ÎșB pathway was confirmed as a downstream target of TNF-induced HAoEC activation, via nuclear translocation of NF-ÎșB and degradation of IÎșB, effects which were abolished by treatment with CZP. In addition, flow cytometry detected an increased production of endothelial microparticles in TNF-activated HAoECs, which was prevented by treatment with CZP. Conclusions: We have found at a cellular level that a clinically available TNF inhibitor, CZP reduces the expression of adhesion molecule expression, and prevents TNF-induced activation of the NF-ÎșB pathway. Furthermore, CZP prevents the production of microparticles by activated endothelial cells. This could be central to the prevention of inflammatory environments underlying these conditions and measurement of microparticles has potential as a novel prognostic marker for future cardiovascular events in this patient group. Disclosure statement: Y.A. received a research grant from UCB. I.B. received a research grant from UCB. S.H. received a research grant from UCB. All other authors have declared no conflicts of interes
Uma revisĂŁo sobre polimerização de olefinas usando catalisadores Ziegler-Natta heterogĂȘneos
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Multinationality and performance literature: a critical review and future research agenda
The literature on the relationship between the degree of multinationality (M) and performance (P) in the context of multinational enterprises (MNEs) has attracted a large volume of research in the past 50 years. Yet, the theoretical foundations and the empirical conclusions concerning the nature of MâP relationship vary greatly, thus call for a critical review and assessment. We examine 135 articles in 39 leading scholarly journals and classic books published during the period 1960â2015. We use an inductive approach and a qualitative content analysis methodology for our comprehensive and critical review of the literature. We incorporate international business, finance, and accounting perspectives in our analysis. We review the conceptualization and measurement of M, P, the findings on MâP relationships, methodologies, and geographic focus. We identify six key inconsistencies in the existing research, which cause ambiguity in the relevant findings. We make eight recommendations for future research to address these inconsistencies. Thus, our study contributes to the central debate in this research field
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