318 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. © IMechE 2004
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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
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Plant-symbiotic fungi as chemical engineers: multi-genome analysis of the Clavicipitaceae reveals dynamics of alkaloid Loci
The fungal family Clavicipitaceae includes plant symbionts and parasites that produce several psychoactive and bioprotective alkaloids. The family includes grass symbionts in the epichloae clade (Epichloë and Neotyphodium species), which are extraordinarily diverse both in their host interactions and in their alkaloid profiles. Epichloae produce alkaloids of four distinct classes, all of which deter insects, and some—including the infamous ergot alkaloids—have potent effects on mammals. The exceptional chemotypic diversity of the epichloae may relate to their broad range of host interactions, whereby some are pathogenic and contagious, others are mutualistic and vertically transmitted (seed-borne), and still others vary in pathogenic or mutualistic behavior. We profiled the alkaloids and sequenced the genomes of 10 epichloae, three ergot fungi (Claviceps species), a morning-glory symbiont (Periglandula ipomoeae), and a bamboo pathogen (Aciculosporium take), and compared the gene clusters for four classes of alkaloids. Results indicated a strong tendency for alkaloid loci to have conserved cores that specify the skeleton structures and peripheral genes that determine chemical variations that are known to affect their pharmacological specificities. Generally, gene locations in cluster peripheries positioned them near to transposon-derived, AT-rich repeat blocks, which were probably involved in gene losses, duplications, and neofunctionalizations. The alkaloid loci in the epichloae had unusual structures riddled with large, complex, and dynamic repeat blocks. This feature was not reflective of overall differences in repeat contents in the genomes, nor was it characteristic of most other specialized metabolism loci. The organization and dynamics of alkaloid loci and abundant repeat blocks in the epichloae suggested that these fungi are under selection for alkaloid diversification. We suggest that such selection is related to the variable life histories of the epichloae, their protective roles as symbionts, and their associations with the highly speciose and ecologically diverse cool-season grasses
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 (1095–1290 CE), the Mamluk regime in Transjordan (1260–1516 CE) and the Ottoman crisis and Celâlî Rebellion(1580–1610 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
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 sixty‐eight ambulatory patients with heart failure (age 67.1 ± 10.9 years, New York Heart Association class 2.3 ± 0.6, left ventricular ejection fraction 39 ± 13.3%, and 21% female) were prospectively enrolled as part of the Studies Investigating Co‐morbidities Aggravating Heart Failure. Muscle wasting as assessed using dual‐energy X‐ray absorptiometry was present in 47 patients (17.5%).
Results
During a mean follow‐up of 67.2 ± 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, N‐terminal pro‐B‐type natriuretic peptide, and iron deficiency, muscle wasting remained an independent predictor of death (hazard ratio 1.80, 95% confidence interval 1.01–3.19, 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 co‐morbidity
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. © Taylor & Francis Group, LLC
Relational processing and working memory capacity in comprehension of relative clause sentences
Griffith Health, School of Applied PsychologyFull Tex
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
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 households’ 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
“Non-invasive, faster and less expensive than MRI” and “the eye is a window to the brain” 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 (n = 27) and secondary progressive (n = 10) course on two occasions with a median interval of 22.4±0.5 months [range 19–27]. 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
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