1,175 research outputs found

    Water in the Near IR spectrum of Comet 8P/Tuttle

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    High resolution spectra of Comet 8P/Tuttle were obtained in the frequency range 3440.6-3462.6 cm-1 on 3 January 2008 UT using CGS4 with echelle grating on UKIRT. In addition to recording strong solar pumped fluorescent (SPF) lines of H2O, the long integration time (152 miutes on target) enabled eight weaker H2O features to be assigned, most of which had not previously been identified in cometary spectra. These transitions, which are from higher energy upper states, are similar in character to the so-called 'SH' lines recorded in the post Deep Impact spectrum of comet Tempel 1 (Barber et al., 2007). We have identified certain characteristics that these lines have in common, and which in addition to helping to define this new class of cometary line, give some clues to the physical processes involved in their production. Finally, we derive an H2O rotational temperature of 62+/- K and a water production rate of (1.4+/-0.3)E28 molecules/s.Comment: Paper has been accepted for publication by MNRAS (11/06/09

    Rate-Control or Rhythm-Contol: Where do we stand?

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    Atrial fibrillation is the most common sustained rhythm disturbance and its prevalence is increasing worldwide due to the progressive aging of the population. Current guidelines clearly depict the gold standard management of acute symptomatic atrial fibrillation but the best-long term approach for first or recurrent atrial fibrillation is still debated with regard to quality of life, risk of new hospitalizations, and possible disabling complications, such as thromboembolic stroke, major bleeds and death. Some authors propose that regaining sinus rhythm in all cases, thus re-establishing a physiologic cardiac function not requiring a prolonged antithrombotic therapy, avoids the threat of intracranial or extracranial haemorrhages due to Vitamin K antagonists or aspirin. On the contrary, advocates of a rate control approach with an accurate antithrombotic prophylaxis propose that such a strategy may avoid the risk of cardiovascular and non cardiovascular side effects related to antiarrhythmic drugs. This review aims to explore the state of our knowledge in order to summarize evidences and issues that need to be furthermore clarified

    Direct analysis of sterols from dried plasma/blood spots by an atmospheric pressure thermal desorption chemical ionization mass spectrometry (APTDCI-MS) method for a rapid screening of Smith-Lemli-Opitz syndrome.

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    Here is proposed a rapid and sensitive method involving atmospheric pressure thermal desorption chemical ionization mass spectrometry (APTDCI-MS) for specific laboratory screening of the Smith– Lemli–Opitz syndrome (SLOS), an inherited defect of cholesterol biosynthesis. Biochemical findings in the blood of SLOS patients are low cholesterol (Chol), high 7- and 8-dehydrocholesterol (DHCs) levels and high DHCs/Chol ratios. The APTDCI proposed method is able to ionize sterols for qualitative and quantitative analysis directly from dried plasma/blood spots. Critical APTDCI parameters – desolvation gas flow and temperature – were optimized analyzing Chol, 7-DHC and cholesteryl stearate standards spotted onto a glass slide acquiring the full scan spectra in positive ion mode. Chol levels in dried plasma spots of unaffected controls (n ¼ 23) obtained by the proposed method were compared with those of the enzymatic method (y ¼ 0.9166x + 0.3811; r ¼ 0.8831) while Chol and DHCs of SLOS patients (n ¼ 9) were compared with the gas chromatography flame ionization detection (GC-FID) method (y ¼ 0.8214x + 0.7388; r ¼ 0.8288). The APTDCI-MS method is also able to differentiate normal from SLOS samples directly analyzing whole blood and washed red cells spotted on paper. In conclusion, the intrinsic analytical high-throughput of APTDCI-MS method for sterol analysis could be useful to screen SLO syndrome

    The effect of age on daily positive emotions and work behaviors

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    This study draws on socioemotional selectivity and person–job fit theories to investigate the emotional bases for age-related differences in daily task crafting and in-role performance. We tested a mediation model in which age is related to positive emotions that in turn predict task crafting and in-role performance. A total of 256 people working in multiple organizations participated in a 5-day diary study. Multilevel modeling showed that, at the person level of analysis, age is significantly and positively related to positive emotions and task crafting and, via crafting, to in-role performance. No significant mediation of high- and low-arousal positive emotions was found between age and task crafting. However, at the day level of analysis, high-arousal positive emotions are positively related to task crafting, and this in turn is positively related to in-role performance. These findings make important theoretical contributions to understanding within-person processes associated with employee age in addition to more traditional between-person factors. They also have implications for managing an age-diverse workforce by means of job crafting.info:eu-repo/semantics/acceptedVersio

    Nutritional quality of pasta sold on the italian market: The food labelling of italian products (FLIP) study

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    Pasta represents a staple food in many populations and, in recent years, an increasing number of pasta items has been placed on the market to satisfy needs and trends. The aims of this work were: (i) to investigate the nutritional composition of the different types of pasta currently sold in Italy by collecting the nutrition facts on their packaging; (ii) to compare energy, nutrient and salt content per 100 g and serving in fresh and dried pasta; (iii) to compare the nutrition declaration in pairs of products with and without different declarations (i.e., gluten free (GF), organic, and nutrition claims (NC)). A total of 756 items, made available by 13 retailers present on the Italian market, were included in the analysis. Data showed a wide difference between dried and fresh pasta, with high inter-type variability. A negligible amount of salt was observed in all types of pasta, except for stuffed products, which had a median high quantity of salt (>1 g/100 g and ~1.5 g/serving). Organic pasta had higher fibre and lower protein contents compared to conventional pasta. GF products were higher in carbohydrate and fat but lower in fibre and protein than not-GF products, while only a higher fibre content was found in pasta with NC compared to products not boasting claims. Overall, the results show high variability in terms of nutrition composition among the pasta items currently on the market, supporting the importance of reading and understanding food labels for making informed food choices

    Random Graph-Homomorphisms and Logarithmic Degree

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    A graph homomorphism between two graphs is a map from the vertex set of one graph to the vertex set of the other graph, that maps edges to edges. In this note we study the range of a uniformly chosen homomorphism from a graph G to the infinite line Z. It is shown that if the maximal degree of G is `sub-logarithmic', then the range of such a homomorphism is super-constant. Furthermore, some examples are provided, suggesting that perhaps for graphs with super-logarithmic degree, the range of a typical homomorphism is bounded. In particular, a sharp transition is shown for a specific family of graphs C_{n,k} (which is the tensor product of the n-cycle and a complete graph, with self-loops, of size k). That is, given any function psi(n) tending to infinity, the range of a typical homomorphism of C_{n,k} is super-constant for k = 2 log(n) - psi(n), and is 3 for k = 2 log(n) + psi(n)

    CN Morphology Studies of Comet 103P/Hartley 2

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    We report on narrowband CN imaging of Comet 103P/Hartley 2 obtained at Lowell Observatory on 39 nights from 2010 July until 2011 January. We observed two features, one generally to the north and the other generally to the south. The CN morphology varied during the apparition: no morphology was seen in July; in August and September the northern feature dominated and appeared as a mostly face-on spiral; in October, November, and December the northern and southern features were roughly equal in brightness and looked like more side-on corkscrews; in January the southern feature was dominant but the morphology was indistinct due to very low signal. The morphology changed smoothly during each night and similar morphology was seen from night to night. However, the morphology did not exactly repeat each rotation cycle, suggesting that there is a small non-principal axis rotation. Based on the repetition of the morphology, we find evidence that the fundamental rotation period was increasing: 16.7 hr from August 13-17, 17.2 hr from September 10-13, 18.2 hr from October 12-19, and 18.7 hr from October 31-November 7. We conducted Monte Carlo jet modeling to constrain the pole orientation and locations of the active regions based on the observed morphology. Our preliminary, self-consistent pole solution has an obliquity of 10 deg relative to the comet's orbital plane (i.e., it is centered near RA = 257 deg and Dec=+67 deg with an uncertainty around this position of about 15 deg) and has two mid-latitude sources, one in each hemisphere.Comment: Accepted by The Astronomical Journal; 23 pages of text, 2 tables, 8 figure
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