1,986 research outputs found

    FSR 0190: Another old distant Galactic cluster

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    We are conducting a large programme to classify newly discovered Milky Way star cluster candidates from Froebrich et al. Here we present near-infrared follow-up observations of FSR0190 (α = 20h05m31s.3, δ = 33°34â?²09â?², J2000). The cluster is situated close to the Galactic plane (l = 70°7302, b = +0°9498). It shows a circular shape, and a relatively large number of core helium burning stars - which clearly distinguishes the cluster from the rich field - but no centrally condensed star density profile. We derive an age of more than 7 Gyr, a Galactocentric distance of 10.5 kpc, a distance of 10 kpc from the Sun, and an extinction of AK = 0.8 mag. The estimated mass is at least of the order of 105 Mâ??, and the absolute brightness is MV â?¤ -4.7 mag; both are rather typical properties for Palomar-type globular clusters. © 2007 The Authors. Journal compilation © 2007 RAS

    Recent Introductions for Biological Control in Hawaii–III

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    Searching for jet rotation in Class 0/I sources observed with GEMINI/GNIRS.

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    Original article can be found at: http://www.aanda.org/ Copyright The European Southern ObservatoryContext: In recent years, there has been a number of detections of gradients in the radial velocity profile across jets from young stars. The significance of these results is considerable. They may be interpreted as a signature of jet rotation about its symmetry axis, thereby representing the only existing observational indications supporting the theory that jets extract angular momentum from star-disk systems. However, the possibility that we are indeed observing jet rotation in pre-main sequence systems is undergoing active debate. Aims: To test the validity of a rotation argument, we must extend the survey to a larger sample, including younger sources. Methods: We present the latest results of a radial velocity analysis on jets from Class 0 and I sources, using high resolution data from the infrared spectrograph GNIRS on GEMINI South. We obtained infrared spectra of protostellar jets HH 34, HH 111-H, HH 212 NK1 and SK1. Results: The [Fe II] emission was unresolved in all cases and so Doppler shifts across the jet width could not be accessed. The H2 emission was resolved in all cases except HH 34. Doppler profiles across the molecular emission were obtained, and gradients in radial velocity of typically 3 km s-1 identified. Conclusions: Agreement with previous studies implies they may be interpreted as jet rotation, leading to toroidal velocity and angular momentum flux estimates of 1.5 km s-1 and 1 × 10-5 yr-1 AU km s-1 respectively. However, caution is needed. For example, emission is asymmetric across the jets from HH 212 suggesting a more complex interpretation is warranted. Furthermore, observations for HH 212 and HH 111-H are conducted far from the source implying external influences are more likely to confuse the intrinsic flow kinematics. These observations demonstrate the difficulty of conducting this study from the ground, and highlight the necessity for high angular resolution via adaptive optics or space-based facilities

    Recent Introductions for Biological Control in Hawaii—X

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    Recent Introductions for Biological Control in Hawaii — XI

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    Controlled Natural Language Generation from a Multilingual FrameNet-based Grammar

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    This paper presents a currently bilingual but potentially multilingual FrameNet-based grammar library implemented in Grammatical Framework. The contribution of this paper is two-fold. First, it offers a methodological approach to automatically generate the grammar based on semantico-syntactic valence patterns extracted from FrameNet-annotated corpora. Second, it provides a proof of concept for two use cases illustrating how the acquired multilingual grammar can be exploited in different CNL applications in the domains of arts and tourism

    Can Carbon Nanotubes Deliver on their Promise in Biology? Harnessing Unique Properties for Unparalleled Applications

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    Carbon nanotubes (CNTs) are cylindrical sheets of hexagonally ordered carbon atoms, giving tubes with diameters on the order of a few nanometers and lengths typically in the micrometer range. They may be single- or multiwalled (SWCNTs and MWCNTs respectively). Since the seminal report of their synthesis in 1991, CNTs have fascinated scientists of all stripes. Physicists have been intrigued by their electrical, thermal, and vibrational potential. Materials scientists have worked on integrating them into ultrastrong composites and electronic devices, while chemists have been fascinated by the effects of curvature on reactivity and have developed new synthesis and purification techniques. However, to date no large-scale, real-life biotechnological CNT breakthrough has been industrially adopted and it is proving difficult to justify taking these materials forward into the clinic. We believe that these challenges are not the end of the story, but that a viable carbon nanotube biotechnology is one in which the unique properties of nanotubes bring about an effect that would be otherwise impossible. In this Outlook, we therefore seek to reframe the field by highlighting those biological applications in which the singular properties of CNTs provide some entirely new activity or biological effect as a pointer to "what could be"
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