267 research outputs found
Energy consumption and capacity utilization of galvanizing furnaces
An explicit equation leading to a method for improving furnace efficiency is presented. This equation is dimensionless and can be applied to furnaces of any size and fuel type for the purposes of comparison. The implications for current furnace design are discussed. Currently the technique most commonly used to reduce energy consumption in galvanizing furnaces is to increase burner turndown. This is shown by the analysis presented here actually to worsen the thermal efficiency of the furnace, particularly at low levels of capacity utilization. Galvanizing furnaces are different to many furnaces used within industry, as a quantity of material (in this case zinc) is kept molten within the furnace at all times, even outside production periods. The dimensionless analysis can, however, be applied to furnaces with the same operational function as a galvanizing furnace, such as some furnaces utilized within the glass industry. Š IMechE 2004
Muscle wasting as an independent predictor of survival in patients with chronic heart failure
Background:
Skeletal muscle wasting is an extremely common feature in patients with heart failure, affecting approximately 20% of ambulatory patients with even higher values during acute decompensation. Its occurrence is associated with reduced exercise capacity, muscle strength, and quality of life. We sought to investigate if the presence of muscle wasting carries prognostic information.
Methods:
Two hundred sixtyâeight ambulatory patients with heart failure (age 67.1 Âą 10.9 years, New York Heart Association class 2.3 Âą 0.6, left ventricular ejection fraction 39 Âą 13.3%, and 21% female) were prospectively enrolled as part of the Studies Investigating Coâmorbidities Aggravating Heart Failure. Muscle wasting as assessed using dualâenergy Xâray absorptiometry was present in 47 patients (17.5%).
Results
During a mean followâup of 67.2 Âą 28.02 months, 95 patients (35.4%) died from any cause. After adjusting for age, New York Heart Association class, left ventricular ejection fraction, creatinine, Nâterminal proâBâtype natriuretic peptide, and iron deficiency, muscle wasting remained an independent predictor of death (hazard ratio 1.80, 95% confidence interval 1.01â3.19, P = 0.04). This effect was more pronounced in patients with heart failure with reduced than in heart failure with preserved ejection fraction.
Conclusions:
Muscle wasting is an independent predictor of death in ambulatory patients with heart failure. Clinical trials are needed to identify treatment approaches to this coâmorbidity
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Visual similarity effects on short-term memory for order: The case of verbally labeled pictorial stimuli
Four experiments examined the effect of visual similarity on immediate memory for order. Experiments 1 and 2 used easily nameable line drawings. Following a sequential presentation in either silent or suppression conditions, participants were presented with the drawings in a new, random order and were required to remember their original serial position. In Experiment 3, participants first learned to associate a verbal label with an abstract matrix pattern. Then they completed an immediate memory task in which they had to name the matrices aloud during presentation. At recall, the task required remembering either the order of the matrices or the order of their names. In Experiment 4, participants learned to associate nonword labels with schematic line drawings of faces; the phonemic similarity of the verbal labels was also manipulated. All four experiments indicate that the representations supporting performance comprise both verbal and visual features. The results are consistent with a multiattribute encoding view
English in product advertisements in non-english speaking countries in western europe: Product image and comprehension of the text
Although English has been shown to be the most frequently used foreign language in product advertisements in countries where it is not the native language, little is known about its effects. This article examines the response to advertisements in English compared to the response to the same ad in the local language in Western Europe on members of the target group for which the ad was intended: 715 young, highly educated female consumers. The use of English in a product ad does not appear to have any impact on image and price of the product, but it does affect text comprehension: the meaning of almost 40% of the English phrases was not understood. These results were the same for all countries involved in the study, irrespective of whether the respondents\u27 (self-) reported proficiency in English is high or low. Š Taylor & Francis Group, LLC
Spike-Timing Theory of Working Memory
Working memory (WM) is the part of the brain's memory system that provides temporary storage and manipulation of information necessary for cognition. Although WM has limited capacity at any given time, it has vast memory content in the sense that it acts on the brain's nearly infinite repertoire of lifetime long-term memories. Using simulations, we show that large memory content and WM functionality emerge spontaneously if we take the spike-timing nature of neuronal processing into account. Here, memories are represented by extensively overlapping groups of neurons that exhibit stereotypical time-locked spatiotemporal spike-timing patterns, called polychronous patterns; and synapses forming such polychronous neuronal groups (PNGs) are subject to associative synaptic plasticity in the form of both long-term and short-term spike-timing dependent plasticity. While long-term potentiation is essential in PNG formation, we show how short-term plasticity can temporarily strengthen the synapses of selected PNGs and lead to an increase in the spontaneous reactivation rate of these PNGs. This increased reactivation rate, consistent with in vivo recordings during WM tasks, results in high interspike interval variability and irregular, yet systematically changing, elevated firing rate profiles within the neurons of the selected PNGs. Additionally, our theory explains the relationship between such slowly changing firing rates and precisely timed spikes, and it reveals a novel relationship between WM and the perception of time on the order of seconds
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Modelling climate and societal resilience in the Eastern Mediterranean in the last Millennium
This article analyses high-quality hydroclimate proxy records and spatial reconstructions from the Central and Eastern Mediterranean and compares them with two Earth System Model simulations (CCSM4, MPI-ESM-P) for the Crusader period in the Levant (1095â1290 CE), the Mamluk regime in Transjordan (1260â1516 CE) and the Ottoman crisis and CelâlĂŽ Rebellion(1580â1610 CE). During the three time intervals, environmental and climatic stress tested the resilience of complex societies.We find that the multidecadal precipitation and drought variations in the Central and Eastern Mediterranean cannot be explained by external forcings (solar variations, tropical volcanism); rather they were driven by internal climate dynamics. Our research emphasises the challenges, opportunities and limitations of linking proxy records, palaeoreconstructions and model simulations to better understand how climate can affect human history
Expanding the Social Security Net in South Africa: Opportunities, Challenges and Constraints
Rapid increases in government expenditure on social security between 2000 and 2006 has further increased poor householdsââŹâ˘ reliance on welfare grants and has been important in the fight against poverty. Already there is evidence of a substitution taking place within the social budget: expenditure on education and health seems to have declined in favour of increased welfare transfer expenditure
High Resolution Spectral Domain Optical Coherence Tomography (SD-OCT) in Multiple Sclerosis: The First Follow Up Study over Two Years
âNon-invasive, faster and less expensive than MRIâ and âthe eye is a window to the brainâ are recent slogans promoting optical coherence tomography (OCT) as a new surrogate marker in multiple sclerosis (MS). Indeed, OCT allows for the first time a non-invasive visualization of axons of the central nervous system (CNS). Reduction of retina nerve fibre layer (RNFL) thickness was suggested to correlate with disease activity and duration. However, several issues are unclear: Do a few million axons, which build up both optic nerves, really resemble billions of CNS neurons? Does global CNS damage really result in global RNFL reduction? And if so, does global RNFL reduction really exist in all MS patients, and follow a slowly but steadily ongoing pattern? How can these (hypothesized) subtle global RNFL changes be reliably measured and separated from the rather gross RNFL changes caused by optic neuritis? Before generally being accepted, this interpretation needs further critical and objective validation.We prospectively studied 37 MS patients with relapsing remitting (nâ=â27) and secondary progressive (nâ=â10) course on two occasions with a median interval of 22.4Âą0.5 months [range 19â27]. We used the high resolution spectral domain (SD-)OCT with the Spectralis 3.5 mm circle scan protocol with locked reference images and eye tracking mode. Patients with an attack of optic neuritis within 12 months prior to the onset of the study were excluded.Although the disease was highly active over the observation period in more than half of the included relapsing remitting MS patients (19 patients/32 relapses) and the initial RNFL pattern showed a broad range, from normal to markedly reduced thickness, no significant changes between baseline and follow-up examinations could be detected.These results show that caution is required when using OCT for monitoring disease activity and global axonal injury in MS
Impaired psychological recovery in the elderly after the Niigata-Chuetsu Earthquake in Japan:a population-based study
BACKGROUND: An earthquake measuring 6.8 on the Richter scale struck the Niigata-Chuetsu region of Japan at 5.56 P.M. on the 23rd of October, 2004. The earthquake was followed by sustained occurrence of numerous aftershocks, which delayed reconstruction of community lifelines. Even one year after the earthquake, 9,160 people were living in temporary housing. Such a devastating earthquake and life after the earthquake in an unfamiliar environment should cause psychological distress, especially among the elderly. METHODS: Psychological distress was measured using the 12-item General Health Questionnaire (GHQ-12) in 2,083 subjects (69% response rate) who were living in transient housing five months after the earthquake. GHQ-12 was scored using the original method, Likert scoring and corrected method. The subjects were asked to assess their psychological status before the earthquake, their psychological status at the most stressful time after the earthquake and their psychological status at five months after the earthquake. Exploratory and confirmatory factor analysis was used to reveal the factor structure of GHQ12. Multiple regression analysis was performed to analyze the relationship between various background factors and GHQ-12 score and its subscale. RESULTS: GHQ-12 scores were significantly elevated at the most stressful time and they were significantly high even at five months after the earthquake. Factor analysis revealed that a model consisting of two factors (social dysfunction and dysphoria) using corrected GHQ scoring showed a high level of goodness-of-fit. Multiple regression analysis revealed that age of subjects affected GHQ-12 scores. GHQ-12 score as well as its factor 'social dysfunction' scale were increased with increasing age of subjects at five months after the earthquake. CONCLUSION: Impaired psychological recovery was observed even at five months after the Niigata-Chuetsu Earthquake in the elderly. The elderly were more affected by matters relating to coping with daily problems
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