3,669 research outputs found
Star Formation in Transient Molecular Clouds
We present the results of a numerical simulation in which star formation
proceeds from an initially unbound molecular cloud core. The turbulent motions,
which dominate the dynamics, dissipate in shocks leaving a quiescent region
which becomes gravitationally bound and collapses to form a small multiple
system. Meanwhile, the bulk of the cloud escapes due to its initial supersonic
velocities. In this simulation, the process naturally results in a star
formation efficiency of 50%. The mass involved in star formation depends on the
gas fraction that dissipates sufficient kinetic energy in shocks. Thus, clouds
with larger turbulent motions will result in lower star formation efficiencies.
This implies that globally unbound, and therefore transient giant molecular
clouds (GMCs), can account for the low efficiency of star formation observed in
our Galaxy without recourse to magnetic fields or feedback processes.
Observations of the dynamic stability in molecular regions suggest that GMCs
may not be self-gravitating, supporting the ideas presented in this letter.Comment: 5 pages, 3 figures, accepted for MNRAS as a lette
Australia's service sector: a study in diversity
This paper seeks to dispel some of the myths commonly harboured about service jobs, service trade and the contribution services make to productivity improvements and living standards. Services account for more than three-quarters of national output and for four out of every five jobs.services - employment - international service trade - productivity
Internet freedom for all: public libraries have to get serious about tackling the digital privacy divide
Democratic engagement depends on critique and dialogue. Ian Clark looks at emerging issues related to digital literacy, online privacy and surveillance. Not only is a security divide emerging between those with digital knowledge and skills to protect themselves and those without, but also an intellectual privacy divide. There is scope for public libraries in the UK to teach the skills people need to ensure they can use the internet securely and privately, enabling wider engagement in the democratic process
Queering Relationships
More research exists on LGBTQ+ populations than ever before, and research has been done on people in polyamorous relationships, but very little research exists on LGBTQ+ people and the way their sexuality/ gender identities influence their relationship dynamics (if they do at all). The purpose of this study was to determine if there is a link between sexuality and gender identity and an individual’s likelihood to pursue non-monogamous or polyamorous relationship dynamics. Participants were recruited through word of mouth and from online forums. The participants fully consented either online or in person for the survey or interview process, respectively. The interviews consisted of questions regarding sexual orientation, understanding of non-monogamous relationships, and attitudes/ experiences surrounding monogamy and non-monogamy. The results of the study indicate that LGB+ sexuality, rather than non-cis gender identity, was more closely related to participation in non-monogamous or polyamorous relationship dynamic and that LGBTQ+ people are unlikely to perceive the stigma surrounding polyamory as being the same severity as the stigma surrounding LGBTQ+ folks
Gender Performance in Priscilla
\u27Gender Performance in Priscilla\u27 evaluates the way that the 1994 film The Adventures of Priscilla, Queen of the Desert depicts a wide arrange of gender performances.This paper takes into account not only the gender identities and expressions of the characters in the film, but the way some of these expressions/ identities are racialized and how all of the facets of the characters\u27 genders interact with one another
Formative assessment: A systematic and artistic process of instruction for supporting school and lifelong learning
Formative assessment is a potentially powerful instructional process because the practice of sharing assessment information that supports learning is embedded into the instructional process by design. If the potential of formative assessment is to be realized, it must transform from a collection of abstract theories and research methodologies and become a creative and systematic classroom practice. Policy-makers and school administrators must support this transition from theory into practice, particularly in the early stages of professional adaptation, and design assessment systems that teachers may internalize and enact efficiently. The article explores the hypothesis that many public school teachers are ‘trapped’ within environments which deter them from enacting open and inventive social learning strategies in their own classrooms, which when implemented have great potential to support autonomous learning, realize achievement, and create economically productive lifelong learners. This article therefore reviews the literature on formative assessment in practical settings, and investigates the extent to which teachers perform the basic functions of gathering and using evidence to further learning and development in pursuit of the lifelong learning competencies that are essential in the ‘new economy.’L'évaluation formative est un processus éducatif potentiellement fort car la pratique qui consiste à partager l'information issue de l'évaluation et qui soutient l'apprentissage, est intégrée dans le processus éducatif par définition. Le potentiel de l'évaluation formative peut être atteint si une transformation s'opère à partir d'un ensemble de théories abstraites et de méthodologies de recherche, pour devenir une pratique créative et systématique en classe. Les décideurs politiques et les administrateurs scolaires doivent soutenir cette transition de la théorie à la pratique, en particulier dans les premiers stades de l'adaptation professionnelle, et concevoir des systèmes d'évaluation que les enseignants peuvent internaliser et utiliser de manière efficace. L'article explore l'hypothèse que de nombreux enseignants des écoles publiques sont «piégés» dans des environnements qui les dissuadent d'adopter systématiquement des stratégies d'apprentissage innovantes, constructivistes et sociales dans leur propre salle de classe, qui lorsqu'elles sont mises en pratique, ont un fort potentiel afin de soutenir l'apprentissage autonome, favoriser la réussite scolaire, et créer des apprenants économiquement productifs sur le long terme. Cet article passe donc en revue la documentation existante sur l'évaluation formative dans des situations concrètes, et examine dans quelle mesure les enseignants exercent les fonctions de base telles que la collecte et la mise à profit de données probantes afin d'étendre l'apprentissage et développer sur le long terme des compétences d'apprentissage essentielles dans la «nouvelle économie»
The star formation efficiency and its relation to variations in the initial mass function
We investigate how the dynamical state of a turbulently supported, 1000 solar
mass, molecular cloud affects the properties of the cluster it forms, focusing
our discussion on the star formation efficiency (SFE) and the initial mass
function (IMF). A variety of initial energy states are examined in this paper,
ranging from clouds with PE = 0.1 KE to clouds with PE = 10 KE, and for both
isothermal and piece-wise polytropic equations of state (similar to that
suggested by Larson). It is found that arbitrary star formation efficiencies
are possible, with strongly unbound clouds yielding very low star formation
efficiencies. We suggest that the low star formation efficiency in the
Maddelena cloud may be a consequence of the relatively unbound state of its
internal structure. It is also found that competitive accretion results in the
observed IMF when the clouds have initial energy states of PE >= KE. We show
that under such conditions the shape of the IMF is independent of time in the
calculations. This demonstrates that the global accretion process can be
terminated at any stage in the cluster's evolution, while still yielding a
distribution of stellar masses that is consistent with the observed IMF. As the
clouds become progressively more unbound, competitive accretion is less
important and the protostellar mass function flattens. These results predict
that molecular clouds should be permeated with a distributed population of
stars that follow a flatter than Salpeter IMF.Comment: 8 pages, 6 figures, accepted by MNRAS for publictaion. Now available
through the 'Online Early' schem
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