311 research outputs found
Toward time resolved 4D cardiac CT imaging with patient dose reduction: estimating the global heart motion
published_or_final_versio
Assessment of some heavy metals and physicochemical properties in surface soils of municipal open waste dumpsite in Yenagoa, Nigeria
The current study was designed for the assessment of lead, cadmium and chromium and some physicochemical properties of soils collected from an open dumpsite in Yenagoa, Nigeria. Surface soil samples at two depths (0-10 and 10-20 cm) were randomly collected at the dump field and control site, and were analyzed for physicochemical parameters and contamination by lead, chromium and cadmium using standard analytical methods. The results show that the main dumpsite had higher sand (>80.0%) and lower clay and silt contents than the control site. Soil mean pH varied between 4.89±0.05 in the control and 7.60±0.02 in the dump. Total nitrogen (N) content of the dump soils ranged from 0.06±0.07 to 0.24±0.09% and is slightly higher than that of the control soil. This is reflected in the high value of organic matter (4.71±0.85%) in dump soils. Available P was quite high ranging from 35.00±1.01 to 84.20±1.02 mg/kg. Cation exchange capacity (CEC) varied between 12.98±0.31 and 91.07±0.11 cmol kg−1. ECEC levels were moderate to high ranging from 14.10±0.10 to 91.47±0.11 cmol/kg. All the soil samples had very high base saturation (>90.0%) and exchangeable Ca, Mg, K and Na, far above the critical levels set by FAO for agricultural soil. Average levels of Pb ranged from 14.75±0.05 to 16.14±0.04 mg/kg in the dump and 8.35±0.05 to 8.78±0.07 mg/kg in the control. Mean concentration of Cr in the dump soil varied between 0.05±0.01 and 0.06±0.01 mg/kg, and is slightly higher than the control (0.005±0.01 mg/kg), while Cd was found in trace amounts (<0.0001±0.01 mg/kg). These values are all far below the maximum tolerable levels set by FAO and WHO for agricultural soil. It is suggested that the dumpsite and the control area with their adequate soil nutrients and low levels of metals should eventually be converted to agricultural farmland. No remediation is needed at this time.Keywords: Dump waste soil, heavy metal, soil fertility
Comparative pesticidal activity of dichloromethane extracts of Piper nigrum against Sitophilus zeamais and Callosobruchus maculatus
Piperine a clinically established pesticide was investigated in the seeds, fruit and leaves of Piper nigrum. The dichloromethane extracts obtained from the parts of the plant were analysed through ThinLayer Chromatography (TLC) using silica gel-GF 254 impregnated aluminium plate and various solvent system consisting of chloroform : methanol (8:2), (6:4), ethyl acetate : methanol (9:1), and acetone :hexane (6:4) mixtures showing Rf value of 0.95 corresponding to the standard piperine. In all parts of the plants investigated, acetone : hexane solvent system showed distinct Rf value of 0.95corresponding to the standard piperine. 0.289 mg/ml, 0.578, 0.868, 1.16 and 1.45 mg/ml concentration of dichloromethane seed extracts were used to carry out the pesticidal activities on both pests. Theresults showed that mortality rate on both pests are directly proportional to each equivalent concentration of piperine in the extracts. Pesticidal potency on Sitophilus zeamais was significantlyhigher (
Evaluation of polycyclic aromatic hydrocarbons and some heavy metals in roasted food snacks in Amassoma, Niger Delta, Nigeria
Analysis of raw and roasted ready-to-eat foods namely; Atlantic mackerel (Scomber scombrus), suya beef and plantain (Musa paradiasca) sold and consumed in Amassoma town were screened for the presence of 15 polycyclic aromatic hydrocarbons (PAHs). Concentration of chromium, lead and cadmium were also determined after digestion with aqua regia and analysed using atomic absorption spectrophotometer. Column chromatography, packed with anhydrous Na2SO4 and silica gel was used for PAH extraction with dichloromethane as the eluting solvent. The identification and concentration of PAHs were carried out by gas chromatography GC/FID with the aid of 15 PAH standards. Appreciable amount of benzo[a]pyrene (2.41 μg/g) and benzo[b]fluoranthene (4.51 μg/g) were found present in roasted mackerel fish; while a mean of 7.23 μg/g of benzo[a]anthracene was detected in suya beef. Thirteen (13) other PAHs were present at various concentrations in the smoked fish. No PAH was detected in roasted plantain and in the raw food items. Levels of the heavy metals were found in trace amounts and were below World Health Organization limits for human consumption.Key words: Gas chromatography, benzo[a]pyrene, chromium, lead, smoked fish, suya plantain
Betriebspolitik bei BMW: Kritik der "Arbeitersache"
Wir haben in unseren letzten beiden Artikeln zur Intensivierung der Arbeit in der BRD versucht, auf Basis einer Einschätzung der Akkumulationsbewegung des BRD-Kapitals den allgemeinen Zusammenhang von Intensivierung der Arbeit, Einführung neuerer Entlohnungsmethoden, Druck auf die Lohnrate und Atbeitsplatzunsicherheit darzustellen. 1) Daß die verschiedenen Schichten der Arbeiter unterschiedlich von dieser allgemeinen Tendenz betroffen sind, haben wir nur angedeutet. Dabei tauchte schon das Problem auf, daß die in bestimmten Industriezweigen wohl am stärksten von der Arbeitsintensivierung betroffenen Schichten, nämlich Frauen und Gastarbeiter, wesentlich aus der gegenwärtigen gewerkschaftlichen Organisation der Interessenvertretung herausfallen, was auf der anderen Seite das Problem einschließt, daß diesen Schichten auch weitgehend die Organisationsform fehlt, innerhalb und in Auseinandersetzung mit welcher sie ihre dem Kapital entgegenstehenden Interessen und Bedürfnisse formulieren könnten
Development of a computer-generated model for the coronary arterial tree based on multislice CT and morphometric data
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Effect of heart rate on CT angiography using the enhanced cardiac model of the 4D NCAT
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Between tinkering and transformation: A contemporary appraisal of climate change adaptation research on the world's islands
Islands are at the center of discourses on climate change. Yet despite extensive work on diverse island systems in a changing climate, we still lack an understanding of climate change-related responses amongst islands and what shifting from what might be called “tinkering” (perhaps heat warnings) to “transformational” adaptation (perhaps relocation) means for these vastly different landmasses which are often grouped together by default. Through a systematic review of the climate change adaptation scientific literature, this paper critically reflects on how considering islands as a homogenous ensemble and the use of buzzwords such as “transformational adaptation” may be problematic for diverse island realities under climate change. Our findings show that the adaptation evidence base actually provides literature on contrasting island types and cultural and political contexts, including Small Island Developing States as well as other island territories. This study finds research gaps with respect to regions (e.g., South America, Africa, and Mediterranean) and that there is overall both little evidence of and a lack of context-specific definitions of transformational adaptation in island contexts. The adaptation literature does not yet fully reflect the experiences or needs of islands regarding transitions and transformations throughout history
Virtual clinical trials in medical imaging: a review
The accelerating complexity and variety of medical imaging devices and methods have outpaced the ability to evaluate and optimize their design and clinical use. This is a significant and increasing challenge for both scientific investigations and clinical applications. Evaluations would ideally be done using clinical imaging trials. These experiments, however, are often not practical due to ethical limitations, expense, time requirements, or lack of ground truth. Virtual clinical trials (VCTs) (also known as in silico imaging trials or virtual imaging trials) offer an alternative means to efficiently evaluate medical imaging technologies virtually. They do so by simulating the patients, imaging systems, and interpreters. The field of VCTs has been constantly advanced over the past decades in multiple areas. We summarize the major developments and current status of the field of VCTs in medical imaging. We review the core components of a VCT: computational phantoms, simulators of different imaging modalities, and interpretation models. We also highlight some of the applications of VCTs across various imaging modalities
Transformative versus conservative automotive innovation styles: contrasting the electric vehicle manufacturing strategies for the BMW i3 and Fiat 500e
The automotive industry is a critically important stakeholder influencing the sustainability of passenger transport. How traditional car manufacturers respond to carbon reduction and vehicle targets, alongside other selection pressures, can greatly influence the availability and affordability of new innovations such as electric vehicles. In this paper, we explore the automotive innovation styles surrounding two electric vehicles: the BMW i3, and the Fiat 500e. To do so, we tie together ideas from technological innovation systems and corporate product innovation style. Our results illustrate a case of a “compliance car,” the Fiat 500e, vs. the first mass production EV by a major German car manufacturer, the BMW i3. BMW adheres to a transformative change-shaping innovation style that attempts to promote in-house learning that can create value. Fiat adheres to a conservative sustaining innovation style that attempts to outsource innovation, promotes limited learning, and focuses on maintaining value. Both styles interestingly result in converging product development patterns over time
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