2,044 research outputs found

    Radio emission from satellite-Jupiter interactions (especially Ganymede)

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    Analyzing a database of 26 years of observations of Jupiter from the Nan\c{c}ay Decameter Array, we study the occurrence of Io-independent emissions as a function of the orbital phase of the other Galilean satellites and Amalthea. We identify unambiguously the emissions induced by Ganymede and characterize their intervals of occurrence in CML and Ganymede phase and longitude. We also find hints of emissions induced by Europa and, surprisingly, by Amalthea. The signature of Callisto-induced emissions is more tenuous.Comment: 14 pages, 7 figures, in "Planetary Radio Emissions VIII", G. Fischer, G. Mann, M. Panchenko and P. Zarka eds., Austrian Acad. Sci. Press, Vienna, in press, 201

    Differences in salivary α-amylase levels among women with different taste sensitivities

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    Saliva is the main component of taste receptor cells external environment, and consequently it may have a decisive role in taste perception. Taste sensitivity varies among different individuals. Sensitivity to the compound n-6-propylthiouracil (PROP) has been considerably studied and besides the known influence of genetic background, the contribution of perireceptor environment is not completely clear yet. Salivary α-amylase (one of the main proteins of saliva) is involved in carbohydrate digestion and its enzymatic activity may change the levels of sugars present in the mouth, influencing food perception. To evaluate differences in salivary total protein content and α-amylase activity and expression among individuals with different PROP taste sensitivities. Sixty seven female women (18-30 years old) were classified in one of the three groups of taste sensitivity (non-taster, medium-taster or super-taster), according to the perceived intensity for PROP, using Labeled Magnitude Scales. Saliva was collected without stimulation. Flow rate was calculated by dividing total volume for the 5 minutes collection. Bradford method was used for total protein assessment. Dinitrosalicylic acid assay was used for measuring the starch-hydrolyzing activity of salivary α-amylase, while the expression of this enzyme was evaluated by Wester blot. 20,9% of the subjects were classified as non-taters. The three groups presented similar saliva flow rates and total protein content was not significantly different although a tendency for lower protein concentration in medium-tasters individuals was observed. Salivary α-amylase activity (U/min) was higher in supertasters (P<0,05). Salivary α-amylase activity (U/min) was higher in super-tasters (P<0,05) without any significant differences in expression. In women individual differences in saliva composition can contribute to the different taste sensitivity. One of the differences appears to be α-amylase enzymatic activity. The reason for this deserves to be elucidated, as well as the potential involvement of others salivary proteins

    Influence of taste sensitivity in diet choices and obesity among children.

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    Introduction: The prevalence of childhood overweight and obesity in Portugal is about 35% (Rito et al., 2012). Lifestyle and dietary habits are important risk factors for weight gain. Food choice and acceptance greatly relies on food perception. The evaluation of taste sensitivity in children and its relation to dietary choices and Body Mass Index (BMI) will be important in a context of obesity prevention. Nonetheless, methodologies for accessing taste sensitivity in children needs to be optimized and adjusted and in Portugal there is not an established protocol. Objectives: To test and optimize a protocol for sweet and bitter taste sensitivity, in Portuguese children, adapted from a protocol already used in German children (Knof et al., 2011). Methods: 20 children, 12 boys and 8 girls, with ages between 8 and 10 years old, were presented with 5 concentrations of sweet (3 – 16 g/L sucrose) and 5 concentrations of bitter taste solutions (0,05 – 0,25 g/L caffeine) and asked for selected the ones perceived as different from water. Results: Test conditions, both the type of presentation and time of tests, resulted for children with the ages tested. For sweet taste, the number and range of concentrations from test solutions appeared to be adequate in the age group between 8 and 10 years. For bitter taste in 80% of children the answers were not consensual with the range of concentrations. Conclusions: The results from the present work suggest that the concentrations used for access bitter taste sensitivity in children from other countries are not sensed by Portuguese children, showing the importance of adjusting adequate concentrations according to sociocultural habits. This may be possible being due to the complex pathway for bitter taste transduction

    Changes in saliva proteome in response to bread odour

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    It is widely recognized that smelling food results in a mouth-watering feeling and influences appetite. However, besides changes in volume, little is known about the effects that food odours have on the composition of saliva. The aim of the present study was to access the effects that smelling bread has on saliva proteome and to compare such effects with those of chewing and ingesting it. Besides a significant increase in saliva flow rate, together with a decrease in total protein concentration, bread odour induced changes in the proportion of different salivary proteins. The expression levels of two spots of cystatins and two spots of amylase increased due to olfactory stimulation, similar to what happened with bread mastication, suggesting that odour can allow anticipation of the type of food eaten and consequently the physiological oral changes necessary to that ingestion. An interesting finding was that bread odour increased the expression levels of several protein spots of immunoglobulin chains, which were decreased by both bread or rice mastication. This may be of clinical relevance since food olfactory stimulation of salivary immunoglobulins can be used to potentiate the oral immune function of saliva. Moreover, the effects of bread odour in the levels of salivary proteins, previously observed to be involved in oral food processing led to the hypothesis of an influence of this odour in the sensory perception of foods further ingested. Further studies are needed to elucidate this point, as well as whether the changes observed for bread odour are specific, or if different food odours lead to similar salivary proteome responses

    Hypercalcemia upon denosumab withdrawal in primary hyperparathyroidism: a case report and literature review.

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    Denosumab discontinuation is associated with a rapid increase in bone resorption and a decrease in bone mineral density. Spontaneous vertebral fractures may occur as a side effect of the rebound of bone resorption. Cases of rebound-linked hypercalcemia have also been described, moderate in women with osteoporosis and breast cancer and severe in children receiving oncological doses of denosumab. We report the case of an adult woman with primary hyperparathyroidism and moderate hypercalcemia, treated with denosumab for osteoporosis, who developed severe hypercalcemia and spontaneous vertebral fractures (SVFs) after denosumab discontinuation. An 86-year-old woman with densitometric osteoporosis was treated for 3 years with 60 mg of subcutaneous denosumab every 6 months. She was known to have primary hyperparathyroidism, with a serum albumin-corrected calcium of 2.82 mmol/l (NV 2.15-2.5) at the end of denosumab effect. Nine months after the last denosumab injection, she was hospitalized due to worsening overall health. Clinical evaluation revealed severe hypercalcemia (calcium 3.35 mmol/l). Very high values of bone turnover markers (BTMs) suggested a rebound effect due to denosumab discontinuation. An X-ray showed multiple new SVFs. After injection of denosumab 60 mg, serum calcium rapidly decreased and BTMs were dramatically reduced. A surgical approach by minimally invasive parathyroidectomy allowed for definite resolution of hyperparathyroidism and hypercalcemia. This case suggests that hypercalcemia can be a side consequence of denosumab discontinuation, which can become severe when other causes of hypercalcemia, such as primary hyperparathyroidism, are present

    Cheese sensory evaluation

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    Sensory evaluation is a scientific discipline used to evoke, measure, analyse, and interpreted reactions to characteristics of food as they are perceived by senses of sight, smell, taste, touch, and hearing. Without the proper sensory evaluations techniques (sensorial methodology) it is difficult to assess sensory responses and make logical and sound decisions. Many different types of sensorial methods have been proposed and used to select, trained a sensorial panel and to evaluate and control the sensory quality of cheeses. However, not all of them are suitable for all purpose. According the objectives and the cheese sample, it will be proposed a sensory methods that can be used to define sensory specifications or to select a cheese quality standard. It is important to recognise the the glossary of the cheese terms sensory evaluation, to get a lawful cheese sensory evaluation. Based on the main cheese characteristics ( external appearance, texture, and flavour), that are different and specific of each kind a cheese, sensory cheese evaluation is described and validated in 3 cheese samples

    Biomarkers for seasonal heat stress: A holistic approach

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    Environmental heat stress, present during the hot and dry summers in Mediterranean climate, severely impairs animal’s performance, particularly in animals of high genetic merit. Although heat stress has been considerable studied in dairy cattle, the mechanisms of seasonal acclimation are less well understood. Besides, in Mediterranean region, there are also great interests in small ruminant dairy species, which are even less well studied. Biomarkers may have great potential in identifying levels of thermal stress. Although often referred, blood cortisol does not allow a full understanding of heat stress, due to its circadian cycle and because the confounding with other types of stress. Consequently, new and better non-invasive methods, than allow to assess stress, are necessary. The hair, faeces or saliva fulfil these requirements. Salivary proteins have been extensively studied in humans, due to their potential as non-invasive biomarkers of pathology and physiology. Nonetheless, in the last years, some research emerged demonstrating the value of saliva for farm animal studies. Based on previous line of research, on ruminant salivary proteome and heat stress, we propose to search for salivary and faeces biomarkers of seasonal acclimation to heat stress and to compare them with other well-known physiological and endocrine indicators. Unlike what occurs at tropical climates where animals must combine a high heat tolerance with high performance; in Mediterranean climate due to high climate seasonality, the animals must give priority to the higher physiological versatility. We this purpose we intend: i) to identify reliable biomarkers (saliva, faeces) that measure levels of heat stress in dairy animals; ii) to search for short and long term biomarkers of thermal stress, based on seasonal acclimatization. Consequently, some experiments, that combine responses to acute and chronic heat stress, will be designed. The different known physiological parameters associated with heat stress will be evaluated together with potential biomarkers in saliva and faeces. The temporal inference will show the quality of biomarker for the short and long term

    Ensemble Properties of Comets in the Sloan Digital Sky Survey

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    We present the ensemble properties of 31 comets (27 resolved and 4 unresolved) observed by the Sloan Digital Sky Survey (SDSS). This sample of comets represents about 1 comet per 10 million SDSS photometric objects. Five-band (u,g,r,i,z) photometry is used to determine the comets' colors, sizes, surface brightness profiles, and rates of dust production in terms of the Af{\rho} formalism. We find that the cumulative luminosity function for the Jupiter Family Comets in our sample is well fit by a power law of the form N(< H) \propto 10(0.49\pm0.05)H for H < 18, with evidence of a much shallower fit N(< H) \propto 10(0.19\pm0.03)H for the faint (14.5 < H < 18) comets. The resolved comets show an extremely narrow distribution of colors (0.57 \pm 0.05 in g - r for example), which are statistically indistinguishable from that of the Jupiter Trojans. Further, there is no evidence of correlation between color and physical, dynamical, or observational parameters for the observed comets.Comment: 19 pages, 8 tables, 11 figures, to appear in Icaru

    Jupiter radio emission induced by Ganymede and consequences for the radio detection of exoplanets

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    International audienceBy analysing a database of 26 yr of observations of Jupiter with the Nancay Decameter Array, we unambiguously identify the radio emissions caused by the Ganymede-Jupiter interaction. We study the energetics of these emissions via the distributions of their intensities, duration, and power, and compare them to the energetics of the Io-Jupiter radio emissions. This allows us to demonstrate that the average emitted radio power is proportional to the Poynting flux from the rotating Jupiter's magnetosphere intercepted by the obstacle. We then generalize this result to the radio-magnetic scaling law that appears to apply to all plasma interactions between a magnetized flow and an obstacle, magnetized or not. Extrapolating this scaling law to the parameter range corresponding to hot Jupiters, we predict large radio powers emitted by these objects, that should result in detectable radio flux with new-generation radiotelescopes. Comparing the distributions of the durations of Ganymede-Jupiter and Io-Jupiter emission events also suggests that while the latter results from quasi-permanent Alfven wave excitation by Io, the former likely results from sporadic reconnection between magnetic fields Ganymede and Jupiter, controlled by Jupiter's magnetic field geometry and modulated by its rotation
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