153 research outputs found
The cooling rate of neutron stars after thermonuclear shell flashes
Thermonuclear shell flashes on neutron stars are detected as bright X-ray
bursts. Traditionally, their decay is modeled with an exponential function.
However, this is not what theory predicts. The expected functional form for
luminosities below the Eddington limit, at times when there is no significant
nuclear burning, is a power law. We tested the exponential and power-law
functional forms against the best data available: bursts measured with the
high-throughput Proportional Counter Array (PCA) on board the Rossi X-ray
Timing Explorer. We selected a sample of 35 'clean' and ordinary (i.e., shorter
than a few minutes) bursts from 14 different neutron stars that 1) show a large
dynamic range in luminosity, 2) are the least affected by disturbances by the
accretion disk and 3) lack prolonged nuclear burning through the rp-process. We
find indeed that for every burst a power law is a better description than an
exponential function. We also find that the decay index is steep, 1.8 on
average, and different for every burst. This may be explained by contributions
from degenerate electrons and photons to the specific heat capacity of the
ignited layer and by deviations from the Stefan-Boltzmann law due to changes in
the opacity with density and temperature. Detailed verification of this
explanation yields inconclusive results. While the values for the decay index
are consistent, changes of it with the burst time scale, as a proxy of ignition
depth, and with time are not supported by model calculations.Comment: 10 pages, 7 figures, recommended for publication in A&
Peritoneal function in clinical practice: the importance of follow-up and its measurement in patients. Recommendations for patient information and measurement of peritoneal function
A review is given on peritoneal function, especially ultrafiltration and ultrafiltration failure followed by recommendations on how to translate pathophysiology into clinical practice. The subsequent consequences for management of peritoneal membrane function and for patient information are also included
Epigallocatechin gallate suppresses peritoneal fibrosis in mice.
Long-term peritoneal dialysis (PD) leads to histological changes in the peritoneal membrane. Angiogenesis and inflammation caused by glucose degradation products (GDPs) play crucial roles in peritoneal fibrosis. One such GDP is methylglyoxal (MGO), which enhances the formation of advanced glycation end products (AGEs). AGEs bind to their receptor (RAGE) and activate nuclear factor-κB (NF-κB), which is a key regulator of angiogenesis and inflammation. Recent studies have indicated that (-)-epigallocatechin gallate (EGCG), a tea polyphenol, inhibits angiogenesis and inflammation. Here, we examined whether EGCG suppresses peritoneal fibrosis in mice. Based on preliminary examination, 2mL of 40mM MGO or PD fluid was injected intraperitoneally and EGCG (50mg/kg) or saline was injected subcutaneously for 3weeks. In comparison to PD fluid+saline-treated mice, the peritoneal tissues of MGO+saline-treated mice showed marked thickening of the submesothelial compact zone. In the submesothelial compact zone of the MGO+saline-treated mice, CD31-positive vessels and vascular endothelial growth factor-positive cells were significantly increased, as were inflammation, F4/80-positive macrophages, and monocyte chemotactic protein-1. Moreover, 8-hydroxydeoxyguanosine, a marker of reactive oxygen species, and NF-κB, determined by Southwestern histochemistry, in the submesothelial compact zone were also increased in MGO+saline-treated mice. These changes were attenuated in MGO+EGCG-treated mice. We demonstrated that EGCG treatment suppresses peritoneal fibrosis via inhibition of NF-κB. Furthermore, EGCG inhibits reactive oxygen species production. The results of this study indicate that EGCG is a potentially novel candidate for the treatment of peritoneal fibrosis
Exploring Stance Detection of Opinion Texts: Evaluating the Performance of a Large Language Model: Benchmarking the Performance of Stance Classification by GPT-3-Turbo
In April 2020, a Dutch research team swiftly analyzed public opinions on COVID-19 lockdown relaxations. However, due to time constraints, only a small amount of opinion data could be processed. With the surge of popularity in the field of Natural Language Processing (NLP) and the arrival of tools like ChatGPT, a number of tasks involving Large Language Models (LLMs) have become easier. This study aims to address the effectiveness of these LLMs on stance detection using this COVID-19 opinion corpus. The corpus is chunked and sampled to be used as input for OpenAI's GPT-3.5-Turbo LLM. The machine-generated stances are then evaluated against multiple binary classification metrics. It is shown that these models perform very well in the field of stance detection, with an average F-score of 0.895. However, a significant number of misclassifications are observed in one dataset. Therefore we conclude that while LLMs offer valuable guidelines, it is still crucial to verify their outputs when dealing with complex or important public matters.CSE3000 Research ProjectComputer Science and Engineerin
Definition Menière Groningen : a rational approach to Menière´s disease
Centuries before Prosper Meniere described his classical triadic symptomatology Meniere-like symptoms were already reported. In 1861 Prosper Meniere was actually the first one who described a series of patients with the classical traidic symptomatology of hearing loss, vertigo and tinnitus. The essence of his hypothesis was that the symptoms were caused by a disorder of the labyrinth instead of a vascular cerebral dysfuntion, as had previously been thought. This was published in the 'Gazette Medicinale de Paris' (Meniere 1861). In this paper Prosper Meniere concluded that the auditory apparatus may be suddenly affected causing tinnitus and diminution of hearing. He also stated that the inner ear was the site wich can suddenly be affected causing attacks of vertigo, dizziness, uncertain gait, staggering and falling. The attacks may be accompanied by nausea, vomiting and syncope. He described that the attacks were intermittently followed by hearing loss of incre!
asing severity. In the 20th century the interest to establish an exclusive diagnosis and an adequate therapy was growing. Although different definitions of Meniere's disease for diagnostic, therapeutic and evaluation purposes are proposed, unresolved issues on the definition of the disease are still persistent.
A uniform applicability of the definiton of Meniere's disease is obligatory for clinical and scientific purposes.
Zie: Summary and conclusions
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