Detection of Interstellar Ortho-D2H+ with SOFIA

We report on the detection of the ground-state rotational line of ortho-D2H+ at 1.477 THz (203 mu m) using the German REceiver for Astronomy at Terahertz frequencies (GREAT) on. board the Stratospheric Observatory For Infrared Astronomy (SOFIA). The line is seen in absorption against. far-infrared continuum from the protostellar binary IRAS 16293-2422 in Ophiuchus. The para-D2H+ line at 691.7 GHz was not detected with the APEX telescope toward this position. These D2H+ observations complement our previous detections of para-H2D+ and ortho-H2D+ using SOFIA and APEX. By modeling chemistry and radiative transfer in the dense core surrounding the protostars, we find that the ortho-D2H+ and para-H2D+ absorption features mainly originate in the cool (T <18 K) outer envelope of the core. In contrast, the ortho-H2D+ emission from the core is significantly absorbed by the ambient molecular cloud. Analyses of the combined D2H+ and H2D+ data result in an age estimate of similar to 5. x. 10(5) yr for the core, with an uncertainty of similar to 2. x. 10(5) yr. The core material has probably been pre-processed for another 5. x. 10(5) years in conditions corresponding to those in the ambient molecular cloud. The inferred timescale is more than 10 times the age of the embedded protobinary. The D2H+ and H2D+ ions have large and nearly equal total (ortho+ para) fractional abundances of similar to 10(-9) in the outer envelope. This confirms the central role of H-3 + in the deuterium chemistry in cool, dense gas, and adds support to the prediction of chemistry models that also D-3(+) should be abundant in these conditions.Peer reviewe

ERICA: use of screens and consumption of meals and snacks by Brazilian adolescents

OBJECTIVE To describe the length of exposure to screens and the prevalence of consumption of meals and snacks by Brazilian adolescents in front of screens. METHODS We evaluated 74,589 12 to 17-year old adolescents from 1,247 schools in 124 Brazilian municipalities. A self-administered questionnaire was used. Its segment regarding nutrition contained questions about using TV, computers, and video game systems, having meals while watching TV, and consuming snacks in front of screens. Consumption of meals and snacks in front of screens was analyzed according to the following variables: geographical region, gender, age range, type of school (public or private), and school shift. The prevalences and their respective 95% confidence intervals were estimated under a complex sampling design. RESULTS A great deal of the adolescents (73.5%, 95%CI 72.3-74.7) reported spending two or more hours a day in front of screens. That habit was more frequent among male adolescents, private school students, morning shift students, and students from Brazil’s South region. More than half of the adolescents (56.6%, 95%CI 55.4-57.8) reported almost always or always having meals in front of TV, and 39.6% (95%CI 38.8-40.5) of them said they consumed snacks in front of screens exactly as often. Both situations were the most prevalent ones among the girls, who attended public schools and were from Brazil’s Midwest region. CONCLUSIONS Length of exposure to screens and consumption of meals and snacks almost always or always in front of screens are high among Brazilian adolescents. It is necessary to develop strategies aiming to reduce the length of screen use, considering the media reality that children and adolescents have been experiencing from earlier and earlier ages. That context must therefore be analyzed in an indissociable way.OBJETIVO Descrever o tempo de exposição às telas e a prevalência de consumo de refeições e petiscos em frente a telas em adolescentes brasileiros. MÉTODOS Foram avaliados 74.589 adolescentes de 12 a 17 anos de 1.247 escolas em 124 municípios brasileiros. Foi utilizado questionário autopreenchível, cujo bloco sobre alimentação continha perguntas sobre o uso de TV, computador e videogames, realização de refeições assistindo TV e consumo de petiscos em frente a telas. O consumo de refeições e petiscos em frente a telas foi analisado segundo as variáveis: região geográfica, sexo, faixa etária, tipo de escola (pública ou particular) e turno de estudo. Foram estimadas prevalências e respectivos intervalos de confiança de 95%, considerando-se o desenho de amostra complexa. RESULTADOS Grande parte dos adolescentes (73,5%, IC95% 72,3-74,7) referiu passar duas ou mais horas por dia em frente às telas. Esse hábito foi mais frequente entre os adolescentes do sexo masculino, de escola particular, do turno da manhã e da região Sul do País. Mais da metade dos adolescentes (56,6%, IC95% 55,4-57,8) relatou realizar as refeições quase sempre ou sempre em frente à TV, e 39,6% (IC95% 38,8-40,5) consumiam petiscos em frente às telas com essa mesma frequência. Ambas as situações foram mais prevalentes entre as meninas, que estudavam na rede pública de ensino e da região Centro-Oeste. CONCLUSÕES O tempo de exposição às telas e o consumo de refeições e petiscos quase sempre ou sempre em frente a telas é elevado entre os adolescentes brasileiros. Faz-se necessário desenvolver estratégias que visem à redução do tempo de uso de telas, considerando a realidade midiática que crianças e adolescentes têm vivenciado de forma cada vez mais precoce, devendo-se, portanto, trabalhar esse contexto de forma indissociável

Erratum to: The study of cardiovascular risk in adolescents – ERICA: rationale, design and sample characteristics of a national survey examining cardiovascular risk factor profile in Brazilian adolescents

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PDRs4All III: JWST's NIR spectroscopic view of the Orion Bar

(Abridged) We investigate the impact of radiative feedback from massive stars on their natal cloud and focus on the transition from the HII region to the atomic PDR (crossing the ionisation front (IF)), and the subsequent transition to the molecular PDR (crossing the dissociation front (DF)). We use high-resolution near-IR integral field spectroscopic data from NIRSpec on JWST to observe the Orion Bar PDR as part of the PDRs4All JWST Early Release Science Program. The NIRSpec data reveal a forest of lines including, but not limited to, HeI, HI, and CI recombination lines, ionic lines, OI and NI fluorescence lines, Aromatic Infrared Bands (AIBs including aromatic CH, aliphatic CH, and their CD counterparts), CO2 ice, pure rotational and ro-vibrational lines from H2, and ro-vibrational lines HD, CO, and CH+, most of them detected for the first time towards a PDR. Their spatial distribution resolves the H and He ionisation structure in the Huygens region, gives insight into the geometry of the Bar, and confirms the large-scale stratification of PDRs. We observe numerous smaller scale structures whose typical size decreases with distance from Ori C and IR lines from CI, if solely arising from radiative recombination and cascade, reveal very high gas temperatures consistent with the hot irradiated surface of small-scale dense clumps deep inside the PDR. The H2 lines reveal multiple, prominent filaments which exhibit different characteristics. This leaves the impression of a "terraced" transition from the predominantly atomic surface region to the CO-rich molecular zone deeper in. This study showcases the discovery space created by JWST to further our understanding of the impact radiation from young stars has on their natal molecular cloud and proto-planetary disk, which touches on star- and planet formation as well as galaxy evolution.Comment: 52 pages, 30 figures, submitted to A&

Laboratory spectroscopy techniques to enable observations of interstellar ion chemistry

Molecular ions have long been considered key intermediates in the evolution of molecular complexity in the interstellar medium. However, owing to their reactivity and transient nature, ions have historically proved challenging to study in terrestrial laboratory experiments. In turn, their detection and characterization in space is often contingent upon advances in the laboratory spectroscopic techniques used to measure their spectra. In this Review, we discuss the advances over the past 50 years in laboratory methodologies for producing molecular ions and probing their rotational, vibrational and electronic spectra. We largely focus this discussion around the widespread H(3)(+)cation and the ionic products originating from its reaction with carbon atoms. Finally, we discuss the current frontiers in this research and the technical advances required to address the spectroscopic challenges that they represent. Despite comprising only about 15% of the known molecular inventory of the interstellar medium, molecular ions have an outsized role in driving chemical evolution. This Review examines the advances - and challenges - in laboratory spectroscopy that have enabled the study of ions in space