535 research outputs found
X-ray haloes and star formation in early-type galaxies
High resolution 2D hydrodynamical simulations describing the evolution of the
hot ISM in axisymmetric two-component models of early-type galaxies well
reproduced the observed trends of the X-ray luminosity () and
temperature () with galaxy shape and rotation, however they also
revealed the formation of an exceedingly massive cooled gas disc in rotating
systems. In a follow-up of this study, here we investigate the effects of star
formation in the disc, including the consequent injection of mass, momentum and
energy in the pre-existing interstellar medium. It is found that subsequent
generations of stars originate one after the other in the equatorial region;
the mean age of the new stars is Gyr, and the adopted recipe for star
formation can reproduce the empirical Kennicutt-Schmidt relation. The results
of the previous investigation without star formation, concerning
and of the hot gas, and their trends with galactic shape and
rotation, are confirmed. At the same time, the consumption of most of the cold
gas disc into new stars leads to more realistic final systems, whose cold gas
mass and star formation rate agree well with those observed in the local
universe. In particular, our models could explain the observation of
kinematically aligned gas in massive, fast-rotating early-type galaxies.Comment: 20 pages, 10 figures, 5 tables. Accepted for publication in MNRA
The effects of stellar dynamics on the X-ray emission of flat early-type galaxies
Observational and numerical studies gave hints that the hot gaseous haloes of
ETGs may be sensitive to the galaxy internal kinematics. By using high
resolution 2D hydro simulations, and realistic two-component (stars plus dark
matter) axisymmetric galaxy models, we study the evolution of the hot haloes in
a suite of flat ETGs of fixed mass distribution, but with variable amounts of
azimuthal velocity dispersion and rotational support, including the possibility
of a counter-rotating inner stellar disc. The hot halo is fed by stellar mass
losses and heated by SNIa explosions and thermalization of stellar motions. We
measure the value of the thermalization parameter gamma (the ratio between the
heating due to the relative velocity between the stellar streaming and the ISM
bulk flow, and the heating attainable by complete thermalization of the stellar
streaming motions). We find that 1) the X-ray emission and the average
temperature are larger in fully velocity dispersion supported systems; 2)
0.1<gamma<0.2 for isotropic rotators (with a trend for being larger for lower
dark mass models); 3) systems that are isotropic rotators at large radii with
an inner counter-rotating disc, or fully velocity dispersion supported systems
with an inner rotating disc, have gamma=1, again with a trend to increase for
lower dark mass contents. We also find that the lower X-ray luminosities of
isotropic rotators cannot be explained just by their low gamma, but are due to
the complicated flow structure, consequence of the angular momentum stored at
large radii. X-ray emission weighted temperatures and luminosities nicely match
observed values; the X-ray isophotes are boxy in case of significant galaxy
rotation. Overall, it is found that rotation has an important role to explain
the observational result that more rotationally supported ETGs on average show
a lower X-ray emission [abridged].Comment: 22 pages, 13 figures, accepted for publication in MNRAS. Comments
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Disk dynamics and the X-ray emission of S0 and flat early-type galaxies
With 2D hydrodynamical simulations, we study the evolution of the hot gas
flows in early-type galaxies, focussing on the effects of galaxy rotation on
the thermal and dynamical status of the ISM. The galaxy is modelled as a
two-component axisymmetric system (stars and dark matter), with a variable
amount of azimuthal velocity dispersion and rotational support; the presence of
a counter rotating stellar disk is also considered. It is found that the ISM of
the rotationally supported (isotropic) model is more prone to thermal
instabilities than the fully velocity dispersion counterpart, while its ISM
temperature and X-ray luminosity are lower. The model with counter rotation
shows an intermediate behaviour.Comment: 2 pages, 2 figures. Proceedings of the International Conference
"X-ray Astronomy: towards the next 50 years!", Milan, 1-5 Oct 201
Revisiting gendered representations of humility: an examination of sources from late medieval Italy
During the Middle Ages, gender-neutral representations of humility as a quality linked to spiritual love and voluntary service competed with representations according to gendered patterns, such as those related to the naked and dressed body in terms of its biological and social functions and its appearance. Moving from Dante's examples of humility in Purgatory, Canto X, this article focuses on representations of humility in textual and pictorial sources authored by women and men between the thirteenth and early fourteenth centuries in Italy. By showing the complexity of these representations, this article revisits and reconsiders one-sided historiographical narratives according to which humility in the Middle Ages was intrinsically, persistently and negatively related to feminine suppression and servility
In vitro and in vivo pharmacological activities of 14-o-phenylpropyloxymorphone, a potent mixed mu/delta/kappa-opioid receptor agonist with reduced constipation in mice
Pain, particularly chronic pain, is still an unsolved medical condition. Central goals in pain control are to provide analgesia of adequate efficacy and to reduce complications associated with the currently available drugs. Opioids are the mainstay for the treatment of moderate to severe pain. However, opioid pain medications also cause detrimental side effects, thus highlighting the need of innovative and safer analgesics. Opioids mediate their actions via the activation of opioid receptors, with the mu-opioid receptor as the primary target for analgesia, but also for side effects. One long-standing focus of drug discovery is the pursuit for new opioids exhibiting a favorable dissociation between analgesia and adverse effects. In this study, we describe the in vitro and in vivo pharmacological profiles of the 14-O-phenylpropyl substituted analog of the mu-opioid agonist 14-O-methyloxymorphone (14-OMO). The consequence of the substitution of the 14-O-methyl in 14-OMO with a 14-O-phenylpropyl group on in vitro binding and functional activity, and in vivo behavioral properties (nociception and gastrointestinal motility) was investigated. In binding studies, 14-O-phenylpropyloxymorphone (POMO) displayed very high affinity at mu-, delta-, and kappa-opioid receptors (Ki values in nM, mu:delta:kappa = 0.073:0.13:0.30) in rodent brain membranes, with complete loss of mu-receptor selectivity compared to 14-OMO. In guinea-pig ileum and mouse vas deferens bioassays, POMO was a highly efficacious and full agonist, being more potent than 14-OMO. In the [35S]GTPÎłS binding assays with membranes from CHO cells expressing human opioid receptors, POMO was a potent mu/delta-receptor full agonist and a kappa-receptor partial agonist. In vivo, POMO was highly effective in acute thermal nociception (hot-plate test, AD50= 0.7 nmol/kg) in mice after subcutaneous administration, with over 70- and 9000-fold increased potency than 14-OMO and morphine, respectively. POMO-induced antinociception is mediated through the activation of the mu-opioid receptor, and it does not involve delta- and kappa-opioid receptors. In the charcoal test, POMO produced fourfold less inhibition of the gastrointestinal transit than 14-OMO and morphine. In summary, POMO emerges as a new potent mixed mu/delta/kappa-opioid receptor agonist with reduced liability to cause constipation at antinociceptive doses
Integrating cliniciansâ opinion in the Bayesian meta-analysis of observational studies: the case of risk factors for falls in community-dwelling older people
Background: despite the widespread application of Bayesian methods in meta-analysis, the incorporation of clinical informative priors based upon expert opinion is rare.
Methods: a questionnaire to elicit beliefs about five risk factors for falls in older people was administered to a sample of geriatricians and general practitioners (GPs). The experts were asked to provide a point estimate and upper and lower limits of each relative risk. The elicited opinions were translated into different prior distributions and included in a Bayesian meta-analysis of prospective studies. Frequentist, Bayesian non-informative and fully Bayesian approaches were compared.
Results: almost all the clinicians provided the requested information. In most cases, the variability across published studies was greater or similar to that across clinicians. Geriatricians provided more consistent estimates than GPs. When fewer studies were available, the use of the informative prior provided by geriatricians reduced the width of the credibility interval with respect to the frequentist or Bayesian non-informative approaches. Enthusiastic and skeptical priors led to results strongly driven by the prior distribution.
Conclusions: this study presents a feasible method for belief elicitation and Bayesian priorsâ assessment. The inclusion of external information showed to be useful when only few and/or heterogeneous studies were available from the literature
VĂȘtir lâhumilitĂ©: de Bono Giamboni Ă Boccacce
Representations of humility deserve far morescholarly attention and analysis than they have thus farreceived only by way of exception. This paper aims atpartially filling this historiographical gap by consideringtopical accounts of humility in some Italian sources fromthe late 13th - early 14th centuries, especially in BonoGiamboni, Dante Alighieri and Giovanni Boccaccio. Inparticular, the paper focuses on the recurring theme ofâdressing humilityâ in the works of the above mentionedauthors with the aim to study and contextualize semanticshifts and usages of a literal and metaphorical juxtapositionâ that of humility and dress â which already knew along biblical and monastic tradition
Role of the JP45-Calsequestrin Complex on Calcium Entry in Slow Twitch Skeletal Muscles
We exploited a variety of mouse models to assess the roles of JP45-CASQ1 (CASQ, calsequestrin) and JP45-CASQ2 on calcium entry in slow twitch muscles. In flexor digitorum brevis (FDB) fibers isolated from JP45-CASQ1-CASQ2 triple KO mice, calcium transients induced by tetanic stimulation rely on calcium entry via La3+- and nifedipine-sensitive calcium channels. The comparison of excitation-coupled calcium entry (ECCE) between FDB fibers from WT, JP45KO, CASQ1KO, CASQ2KO, JP45-CASQ1 double KO, JP45-CASQ2 double KO, and JP45-CASQ1-CASQ2 triple KO shows that ECCE enhancement requires ablation of both CASQs and JP45. Calcium entry activated by ablation of both JP45-CASQ1 and JP45-CASQ2 complexes supports tetanic force development in slow twitch soleus muscles. In addition, we show that CASQs interact with JP45 at Ca2+ concentrations similar to those present in the lumen of the sarcoplasmic reticulum at rest, whereas Ca2+ concentrations similar to those present in the SR lumen after depolarization-induced calcium release cause the dissociation of JP45 from CASQs. Our results show that the complex JP45-CASQs is a negative regulator of ECCE and that tetanic force development in slow twitch muscles is supported by the dynamic interaction between JP45 and CASQs
The Cu-CHA deNOx Catalyst in Action: Temperature-Dependent NH3-Assisted Selective Catalytic Reduction Monitored by Operando XAS and XES
Dietary Indicators of Oral and Pharyngeal Cancer
The relationship between frequency of consumption of a selected number of indicator foods and oral and oropharyngeal cancer risk was analysed in a case-control study conducted in Northern Italy on 105 cases of oral and pharyngeal cancer and 1169 controls in hospital for acute, non-neoplastic or digestive diseases. Besides significant and strong direct associations with tobacco (relative risk, RR = 11.0 for current versus never smokers) and alcohol (RR = 5.8 for upper versus lower consumption tertile), consumption of six food items (milk, meat, cheese, carrots, green vegetables and fruit) were inversely and significantly related to oral and pharyngeal cancer risk. The strongest protection was apparently related to frequent fruit consumption, with RRs of 0.8 and 0.2 in the two highest tertiles. Allowance for major potential confounding factors, including tobacco, alcohol and social class indicators explained only part of the dietary correlates observed. The two items remaining significant after multivariate analysis were fruit (RR = 0.3 for the upper tertile) and alcohol (RR = 3.8 for the upper tertile). The associations observed may simply reflect a generally poorer nutritional status in the cases, although the observation that fruit consumption appears to be a particularly important protective factor against oropharyngeal cencer is of potential interest, in terms of aetiological clues and preventive implication
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