1,488 research outputs found
A combined IRAM and Herschel/HIFI study of cyano(di)acetylene in Orion KL: tentative detection of DC3N
We present a study of cyanoacetylene (HC3N) and cyanodiacetylene (HC5N) in
Orion KL, through observations from two line surveys performed with the IRAM
30m telescope and the HIFI instrument on board the Herschel telescope. The
frequency ranges covered are 80-280 GHz and 480-1906 GHz. We model the observed
lines of HC3N, HC5N, their isotopologues (including DC3N), and vibrational
modes, using a non-LTE radiative transfer code. To investigate the chemical
origin of HC3N and DC3N in Orion KL, we use a time-dependent chemical model. We
detect 40 lines of the ground state of HC3N and 68 lines of its 13C
isotopologues. We also detect 297 lines of six vibrational modes of this
molecule (nu_7, 2nu_7, 3nu_7, nu_6, nu_5, and nu_6+nu_7) and 35 rotational
lines of the ground state of HC5N. We report the first tentative detection of
DC3N in a giant molecular cloud with a DC3N/HC3N abundance ratio of 0.015. We
provide column densities and isotopic and molecular abundances. We also perform
a 2x2" map around Orion IRc2 and we present maps of HC3N lines and maps of
lines of the HC3N vibrational modes nu_6 and nu_7. In addition, a comparison of
our results for HC3N with those in other clouds allows us to derive
correlations between the column density, the FWHM, the mass, and the luminosity
of the clouds. The high column densities of HC3N obtained in the hot core, make
this molecule an excellent tracer of hot and dense gas. In addition, the large
frequency range covered reveals the need to consider a temperature and density
gradient in the hot core in order to obtain better line fits. The high D/H
ratio (comparable to that obtained in cold clouds) that we derive suggests a
deuterium enrichment. Our chemical models indicate that the possible deuterated
HC3N present in Orion KL is formed during the gas-phase. This fact provides new
hints concerning the processes leading to deuteration.Comment: 50 pages, 33 figures, 13 tables. Accepted for publication in A&
HERSCHEL OBSERVATIONS OF EXTRA-ORDINARY SOURCES: H2S AS A PROBE OF DENSE GAS AND POSSIBLY HIDDEN LUMINOSITY TOWARD THE ORION KL HOT CORE
We present Herschel/HIFI observations of the light hydride H2S obtained from the full spectral scan of the Orion Kleinmann-Low nebula (Orion KL) taken as part of the Herschel Observations of EXtra-Ordinary Sources GT (guaranteed time) key program. In total, we observe 52, 24, and 8 unblended or slightly blended features from H2 32S, H2 34S, and H2 33S, respectively. We only analyze emission from the so-called hot core, but emission from the plateau, extended ridge, and/or compact ridge are also detected. Rotation diagrams for ortho and para H2S follow straight lines given the uncertainties and yield T rot = 141 ± 12 K. This indicates H2S is in local thermodynamic equilibrium and is well characterized by a single kinetic temperature or an intense far-IR radiation field is redistributing the population to produce the observed trend. We argue the latter scenario is more probable and find that the most highly excited states (E up gsim 1000 K) are likely populated primarily by radiation pumping. We derive a column density, N tot(H2 32S) = 9.5 ± 1.9 × 1017 cm–2, gas kinetic temperature, T kin = 120 K, and constrain the H2 volume density, gsim 9 × 10 7 cm–3, for the H2S emitting gas. These results point to an H2S origin in markedly dense, heavily embedded gas, possibly in close proximity to a hidden self-luminous source (or sources), which are conceivably responsible for Orion KL's high luminosity. We also derive an H2S ortho/para ratio of 1.7 ± 0.8 and set an upper limit for HDS/H2S of <4.9 × 10 –3
SN 1999ga: a low-luminosity linear type II supernova?
Type II-linear supernovae are thought to arise from progenitors that have
lost most of their H envelope by the time of the explosion, and they are poorly
understood because they are only occasionally discovered. It is possible that
they are intrinsically rare, but selection effects due to their rapid
luminosity evolution may also play an important role in limiting the number of
detections. In this context, the discovery of a subluminous type II-linear
event is even more interesting. We investigate the physical properties and
characterise the explosion site of the type II SN 1999ga, which exploded in the
nearby spiral galaxy NGC 2442. Spectroscopic and photometric observations of SN
1999ga allow us to constrain the energetics of the explosion and to estimate
the mass of the ejected material, shedding light on the nature of the
progenitor star in the final stages of its life. The study of the environment
in the vicinity of the explosion site provides information on a possible
relation between these unusual supernovae and the properties of the galaxies
hosting them. Despite the lack of early-time observations, we provide
reasonable evidence that SN 1999ga was probably a type II-linear supernova that
ejected a few solar masses of material, with a very small amount of radioactive
elements of the order of 0.01 solar masses.Comment: 11 pages, 9 figures. Accepted for publication in A&A (March 28, 2009
Moral enhancement: do means matter morally?
One of the reasons why moral enhancement may be controversial, is because the advantages of moral enhancement may fall upon society rather than on those who are enhanced. If directed at individuals with certain counter-moral traits it may have direct societal benefits by lowering immoral behavior and increasing public safety, but it is not directly clear if this also benefits the individual in question. In this paper, we will discuss what we consider to be moral enhancement, how different means may be used to achieve it and whether the means we employ to reach moral enhancement matter morally. Are certain means to achieve moral enhancement wrong in themselves? Are certain means to achieve moral enhancement better than others, and if so, why? More specifically, we will investigate whether the difference between direct and indirect moral enhancement matters morally. Is it the case that indirect means are morally preferable to direct means of moral enhancement and can we indeed pinpoint relevant intrinsic, moral differences between both? We argue that the distinction between direct and indirect means is indeed morally relevant, but only insofar as it tracks an underlying distinction between active and passive interventions. Although passive interventions can be ethical provided specific safeguards are put in place, these interventions exhibit a greater potential to compromise autonomy and disrupt identity
Nutritional labelling for healthier food or non-alcoholic drink purchasing and consumption.
BACKGROUND: Nutritional labelling is advocated as a means to promote healthier food purchasing and consumption, including lower energy intake. Internationally, many different nutritional labelling schemes have been introduced. There is no consensus on whether such labelling is effective in promoting healthier behaviour. OBJECTIVES: To assess the impact of nutritional labelling for food and non-alcoholic drinks on purchasing and consumption of healthier items. Our secondary objective was to explore possible effect moderators of nutritional labelling on purchasing and consumption. SEARCH METHODS: We searched 13 electronic databases including CENTRAL, MEDLINE and Embase to 26 April 2017. We also handsearched references and citations and sought unpublished studies through websites and trials registries. SELECTION CRITERIA: Eligible studies: were randomised or quasi-randomised controlled trials (RCTs/Q-RCTs), controlled before-and-after studies, or interrupted time series (ITS) studies; compared a labelled product (with information on nutrients or energy) with the same product without a nutritional label; assessed objectively measured purchasing or consumption of foods or non-alcoholic drinks in real-world or laboratory settings. DATA COLLECTION AND ANALYSIS: Two authors independently selected studies for inclusion and extracted study data. We applied the Cochrane 'Risk of bias' tool and GRADE to assess the quality of evidence. We pooled studies that evaluated similar interventions and outcomes using a random-effects meta-analysis, and we synthesised data from other studies in a narrative summary. MAIN RESULTS: We included 28 studies, comprising 17 RCTs, 5 Q-RCTs and 6 ITS studies. Most (21/28) took place in the USA, and 19 took place in university settings, 14 of which mainly involved university students or staff. Most (20/28) studies assessed the impact of labelling on menus or menu boards, or nutritional labelling placed on, or adjacent to, a range of foods or drinks from which participants could choose. Eight studies provided participants with only one labelled food or drink option (in which labelling was present on a container or packaging, adjacent to the food or on a display board) and measured the amount consumed. The most frequently assessed labelling type was energy (i.e. calorie) information (12/28).Eleven studies assessed the impact of nutritional labelling on purchasing food or drink options in real-world settings, including purchases from vending machines (one cluster-RCT), grocery stores (one ITS), or restaurants, cafeterias or coffee shops (three RCTs, one Q-RCT and five ITS). Findings on vending machines and grocery stores were not interpretable, and were rated as very low quality. A meta-analysis of the three RCTs, all of which assessed energy labelling on menus in restaurants, demonstrated a statistically significant reduction of 47 kcal in energy purchased (MD -46.72 kcal, 95% CI -78.35, -15.10, N = 1877). Assuming an average meal of 600 kcal, energy labelling on menus would reduce energy purchased per meal by 7.8% (95% CI 2.5% to 13.1%). The quality of the evidence for these three studies was rated as low, so our confidence in the effect estimate is limited and may change with further studies. Of the remaining six studies, only two (both ITS studies involving energy labels on menus or menus boards in a coffee shop or cafeteria) were at low risk of bias, and their results support the meta-analysis. The results of the other four studies which were conducted in a restaurant, cafeterias (2 studies) or a coffee shop, were not clearly reported and were at high risk of bias.Seventeen studies assessed the impact of nutritional labels on consumption in artificial settings or scenarios (henceforth referred to as laboratory studies or settings). Of these, eight (all RCTs) assessed the effect of labels on menus or placed on a range of food options. A meta-analysis of these studies did not conclusively demonstrate a reduction in energy consumed during a meal (MD -50 kcal, 95% CI -104.41, 3.88, N = 1705). We rated the quality of the evidence as low, so our confidence in the effect estimate is limited and may change with further studies.Six laboratory studies (four RCTs and two Q-RCTs) assessed the impact of labelling a single food or drink option (such as chocolate, pasta or soft drinks) on energy consumed during a snack or meal. A meta-analysis of these studies did not demonstrate a statistically significant difference in energy (kcal) consumed (SMD 0.05, 95% CI -0.17 to 0.27, N = 732). However, the confidence intervals were wide, suggesting uncertainty in the true effect size. We rated the quality of the evidence as low, so our confidence in the effect estimate is limited and may change with further studies.There was no evidence that nutritional labelling had the unintended harm of increasing energy purchased or consumed. Indirect evidence came from five laboratory studies that involved mislabelling single nutrient content (i.e. placing low energy or low fat labels on high-energy foods) during a snack or meal. A meta-analysis of these studies did not demonstrate a statistically significant increase in energy (kcal) consumed (SMD 0.19, 95% CI -0.14to 0.51, N = 718). The effect was small and the confidence intervals wide, suggesting uncertainty in the true effect size. We rated the quality of the evidence from these studies as very low, providing very little confidence in the effect estimate. AUTHORS' CONCLUSIONS: Findings from a small body of low-quality evidence suggest that nutritional labelling comprising energy information on menus may reduce energy purchased in restaurants. The evidence assessing the impact on consumption of energy information on menus or on a range of food options in laboratory settings suggests a similar effect to that observed for purchasing, although the evidence is less definite and also of low quality.Accordingly, and in the absence of observed harms, we tentatively suggest that nutritional labelling on menus in restaurants could be used as part of a wider set of measures to tackle obesity. Additional high-quality research in real-world settings is needed to enable more certain conclusions.Further high-quality research is also needed to address the dearth of evidence from grocery stores and vending machines and to assess potential moderators of the intervention effect, including socioeconomic status
Particularly Efficient Star Formation in M33
The Star Formation (SF) rate in galaxies is an important parameter at all
redshifts and evolutionary stages of galaxies. In order to understand the
increased SF rates in intermediate redshift galaxies one possibility is to
study star formation in local galaxies with properties frequently found at this
earlier epoch like low metallicity and small size. We present sensitive
observations of the molecular gas in M 33, a small Local Group spiral at a
distance of 840 kpc which shares many of the characteristics of the
intermediate redshift galaxies. The observations were carried out in the
CO(2--1) line with the HERA heterodyne array on the IRAM 30 m telescope. A
11\arcmin22\arcmin region in the northern part of M 33 was observed,
reaching a detection threshold of a few 10 \msol. The correlation in this
field between the CO emission and tracers of SF (8\mum, 24\mum, \Ha, FUV) is
excellent and CO is detected very far North, showing that molecular gas forms
far out in the disk even in a small spiral with a subsolar metallicity. One
major molecular cloud was discovered in an interarm region with no HI peak and
little if any signs of SF -- without a complete survey this cloud would never
have been found. The radial dependence of the CO emission has a scale length
similar to the dust emission, less extended than the \Ha or FUV. If, however,
the \ratioo ratio varies inversely with metallicity, then the scale length of
the H becomes similar to that of the \Ha or FUV. Comparing the SF rate to
the H mass shows that M 33, like the intermediate redshift galaxies it
resembles, has a significantly higher SF efficiency than large local universe
spirals.Comment: 16 pages, 15 figure
Herschel observations of EXtraordinary Sources: Analysis of the full Herschel/HIFI molecular line survey of Sagittarius B2(N)
A sensitive broadband molecular line survey of the Sagittarius B2(N)
star-forming region has been obtained with the HIFI instrument on the Herschel
Space Observatory, offering the first high-spectral resolution look at this
well-studied source in a wavelength region largely inaccessible from the ground
(625-157 um). From the roughly 8,000 spectral features in the survey, a total
of 72 isotopologues arising from 44 different molecules have been identified,
ranging from light hydrides to complex organics, and arising from a variety of
environments from cold and diffuse to hot and dense gas. We present an LTE
model to the spectral signatures of each molecule, constraining the source
sizes for hot core species with complementary SMA interferometric observations,
and assuming that molecules with related functional group composition are
cospatial. For each molecule, a single model is given to fit all of the
emission and absorption features of that species across the entire 480-1910 GHz
spectral range, accounting for multiple temperature and velocity components
when needed to describe the spectrum. As with other HIFI surveys toward massive
star forming regions, methanol is found to contribute more integrated line
intensity to the spectrum than any other species. We discuss the molecular
abundances derived for the hot core, where the local thermodynamic equilibrium
approximation is generally found to describe the spectrum well, in comparison
to abundances derived for the same molecules in the Orion KL region from a
similar HIFI survey.Comment: Accepted to ApJ. 64 pages, 14 figures. Truncated abstrac
Benevolent characteristics promote cooperative behaviour among humans
Cooperation is fundamental to the evolution of human society. We regularly
observe cooperative behaviour in everyday life and in controlled experiments
with anonymous people, even though standard economic models predict that they
should deviate from the collective interest and act so as to maximise their own
individual payoff. However, there is typically heterogeneity across subjects:
some may cooperate, while others may not. Since individual factors promoting
cooperation could be used by institutions to indirectly prime cooperation, this
heterogeneity raises the important question of who these cooperators are. We
have conducted a series of experiments to study whether benevolence, defined as
a unilateral act of paying a cost to increase the welfare of someone else
beyond one's own, is related to cooperation in a subsequent one-shot anonymous
Prisoner's dilemma. Contrary to the predictions of the widely used inequity
aversion models, we find that benevolence does exist and a large majority of
people behave this way. We also find benevolence to be correlated with
cooperative behaviour. Finally, we show a causal link between benevolence and
cooperation: priming people to think positively about benevolent behaviour
makes them significantly more cooperative than priming them to think
malevolently. Thus benevolent people exist and cooperate more
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