Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Nature ; 597(7877): 485-488, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34552255

RESUMO

Star formation in half of massive galaxies was quenched by the time the Universe was 3 billion years old1. Very low amounts of molecular gas seem to be responsible for this, at least in some cases2-7, although morphological gas stabilization, shock heating or activity associated with accretion onto a central supermassive black hole are invoked in other cases8-11. Recent studies of quenching by gas depletion have been based on upper limits that are insufficiently sensitive to determine this robustly2-7, or stacked emission with its problems of averaging8,9. Here we report 1.3 mm observations of dust emission from 6 strongly lensed galaxies where star formation has been quenched, with magnifications of up to a factor of 30. Four of the six galaxies are undetected in dust emission, with an estimated upper limit on the dust mass of 0.0001 times the stellar mass, and by proxy (assuming a Milky Way molecular gas-to-dust ratio) 0.01 times the stellar mass in molecular gas. This is two orders of magnitude less molecular gas per unit stellar mass than seen in star forming galaxies at similar redshifts12-14. It remains difficult to extrapolate from these small samples, but these observations establish that gas depletion is responsible for a cessation of star formation in some fraction of high-redshift galaxies.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32832939

RESUMO

We illustrate the extraordinary potential of the (far-IR) Origins Survey Spectrometer (OSS) on board the Origins Space Telescope (OST) to address a variety of open issues on the co-evolution of galaxies and AGNs. We present predictions for blind surveys, each of 1000 h, with different mapped areas (a shallow survey covering an area of 10 deg2 and a deep survey of 1 deg2) and two different concepts of the OST/OSS: with a 5.9m telescope (Concept 2, our reference configuration) and with a 9.1 m telescope (Concept 1, previous configuration). In 1000 h, surveys with the reference concept will detect from ~ 1.9 × 106 to ~ 8.7 × 106 lines from ~ 4.8 × 105-2.7 × 106 star-forming galaxies and from ~ 1.4 × 104 to ~ 3.8 × 104 lines from ~ 1.3 × 104-3.5 × 104 AGNs. The shallow survey will detect substantially more sources than the deep one; the advantage of the latter in pushing detections to lower luminosities/higher redshifts turns out to be quite limited. The OST/OSS will reach, in the same observing time, line fluxes more than one order of magnitude fainter than the SPICA/SMI and will cover a much broader redshift range. In particular it will detect tens of thousands of galaxies at z ≥ 5, beyond the reach of that instrument. The polycyclic aromatic hydrocarbons lines are potentially bright enough to allow the detection of hundreds of thousands of star-forming galaxies up to z ~ 8.5, i.e. all the way through the re-ionization epoch. The proposed surveys will allow us to explore the galaxy-AGN co-evolution up to z ~ 5.5 - 6 with very good statistics. OST Concept 1 does not offer significant advantages for the scientific goals presented here.

3.
Psychol Trauma ; 2023 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-36913296

RESUMO

Trauma-informed care has become a pillar of competent psychological services. A foundation in understanding trauma and its treatment should be viewed as essential for clinical psychologists entering the field, as working with individuals that have experienced trauma is inevitable. OBJECTIVE: The objective of this study was to evaluate the number of accredited doctoral programs in clinical psychology that require a course in trauma-informed theory and intervention in their curriculum. METHOD: Clinical psychology programs accredited by the American Psychological Association were surveyed to determine their requirement for a course related to trauma-informed care. Program information was initially reviewed online and in the absence of clear indication within their program websites, survey questions were sent to the program Chair and/or Directors of Clinical Training. RESULTS: Data were obtained from 193 of the 254 APA-accredited programs included in this survey process. Only nine (5%) require a course related to trauma-informed care. Of these, five were PhD programs and four were PsyD programs. This equates to 202 (8%) of graduating doctoral students having been required to take a course related to trauma-informed care. CONCLUSIONS: Trauma exposure is common and a major factor to be considered in the development of psychological disorders and overall physical and emotional wellbeing. As a result, clinical psychologists should enter the field with a foundation in understanding the impact and treatment of trauma exposure. However, only a minority of graduating doctoral students have been required to take a course related to this topic in their graduate curriculum. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

4.
Dalton Trans ; 39(11): 2772-4, 2010 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-20200702

RESUMO

Investigating the methods commonly used to evaluate in vitro cytotoxicity of novel compounds, specifically non-covalent DNA binders, identifies that these methods may not be appropriate. The level of anticancer activity depends not only on the incubation time but also on the absolute amount (number of moles) of drug compound applied, rather than the concentration.


Assuntos
Antineoplásicos/química , Complexos de Coordenação/química , DNA/química , Antineoplásicos/toxicidade , Linhagem Celular Tumoral , Complexos de Coordenação/toxicidade , DNA/metabolismo , Humanos , Iminas/química , Ferro/química
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa