2,816 research outputs found
WL 17: A Young Embedded Transition Disk
We present the highest spatial resolution ALMA observations to date of the
Class I protostar WL 17 in the Ophiuchus L1688 molecular cloud complex,
which show that it has a 12 AU hole in the center of its disk. We consider
whether WL 17 is actually a Class II disk being extincted by foreground
material, but find that such models do not provide a good fit to the broadband
SED and also require such high extinction that it would presumably arise from
dense material close to the source such as a remnant envelope. Self-consistent
models of a disk embedded in a rotating collapsing envelope can nicely
reproduce both the ALMA 3 mm observations and the broadband SED of WL 17. This
suggests that WL 17 is a disk in the early stages of its formation, and yet
even at this young age the inner disk has been depleted. Although there are
multiple pathways for such a hole to be created in a disk, if this hole were
produced by the formation of planets it could place constraints on the
timescale for the growth of planetesimals in protoplanetary disks.Comment: 7 pages, 3 figures, 2 tables, accepted for publication in ApJ
Protoplanetary Disks in the Orion Nebula Cluster: Gas Disk Morphologies and Kinematics as seen with ALMA
We present Atacama Large Millimeter Array CO(32) and HCO(43)
observations covering the central region of
the Orion Nebula Cluster (ONC). The unprecedented level of sensitivity
(0.1 mJy beam) and angular resolution ( AU) of these line observations enable us to search for gas-disk
detections towards the known positions of submillimeter-detected dust disks in
this region. We detect 23 disks in gas: 17 in CO(32), 17 in HCO(43),
and 11 in both lines. Depending on where the sources are located in the ONC, we
see the line detections in emission, in absorption against the warm background,
or in both emission and absorption. We spectrally resolve the gas with km
s channels, and find that the kinematics of most sources are consistent
with Keplerian rotation. We measure the distribution of gas-disk sizes and find
typical radii of 50-200 AU. As such, gas disks in the ONC are compact in
comparison with the gas disks seen in low-density star-forming regions. Gas
sizes are universally larger than the dust sizes. However, the gas and dust
sizes are not strongly correlated. We find a positive correlation between gas
size and distance from the massive star Ori C, indicating that disks
in the ONC are influenced by photoionization. Finally, we use the observed
kinematics of the detected gas lines to model Keplerian rotation and infer the
masses of the central pre-main-sequence stars. Our dynamically-derived stellar
masses are not consistent with the spectroscopically-derived masses, and we
discuss possible reasons for this discrepancy.Comment: 42 pages, 31 figure
Proposed Treatment Protocols for Sex Offenders Based on Sub-Typology
Based on the findings of Robertiello and Terry (2007) this paper evaluates similarities in sex offender sub-types and proposes grouping similar sub-types together for the purpose of treatment. Those sub-types with similar characteristics or are found to have similar responses to treatment options can be grouped together either in prison, in-patient, or out-patient settings and may prove to be more effective treatment protocols than current “one size fits all” sex offender treatment programs. This paper reviews the past 30 years of research on treatment for specific sub-types and integrates it into a larger framework while offering suggestions for future research on the efficacy of grouping these sub-types together. Finally, this review offers the suggestion of providing sexuality training to sex offenders to promote more healthy sexual interactions post treatment.No embarg
Agrarian way
My thesis is really in three fold. Since my work has its origin in the recollections of my earliest childhood memories, I will explain how the pieces in my show are a result of those early memories. Next I will explore how the pieces I design are influenced by my childhood observations and experiences with farm life and agrarian equipment. Finally, I will consider the direction of my future work, and how it can continue to grow and mature
Using transcranial direct-current stimulation (tDCS) to understand cognitive processing
Noninvasive brain stimulation methods are becoming increasingly common tools in the kit of the cognitive scientist. In particular, transcranial direct-current stimulation (tDCS) is showing great promise as a tool to causally manipulate the brain and understand how information is processed. The popularity of this method of brain stimulation is based on the fact that it is safe, inexpensive, its effects are long lasting, and you can increase the likelihood that neurons will fire near one electrode and decrease the likelihood that neurons will fire near another. However, this method of manipulating the brain to draw causal inferences is not without complication. Because tDCS methods continue to be refined and are not yet standardized, there are reports in the literature that show some striking inconsistencies. Primary among the complications of the technique is that the tDCS method uses two or more electrodes to pass current and all of these electrodes will have effects on the tissue underneath them. In this tutorial, we will share what we have learned about using tDCS to manipulate how the brain perceives, attends, remembers, and responds to information from our environment. Our goal is to provide a starting point for new users of tDCS and spur discussion of the standardization of methods to enhance replicability.The authors declare that they had no conflicts of interest with respect to their authorship or the publication of this article. This work was supported by grants from the National Institutes of Health (R01-EY019882, R01-EY025272, P30-EY08126, F31-MH102042, and T32-EY007135). (R01-EY019882 - National Institutes of Health; R01-EY025272 - National Institutes of Health; P30-EY08126 - National Institutes of Health; F31-MH102042 - National Institutes of Health; T32-EY007135 - National Institutes of Health)Accepted manuscrip
A VLA Survey For Faint Compact Radio Sources in the Orion Nebula Cluster
We present Karl G. Janksy Very Large Array (VLA) 1.3 cm, 3.6 cm, and 6 cm
continuum maps of compact radio sources in the Orion Nebular Cluster. We
mosaicked 34 square arcminutes at 1.3 cm, 70 square arcminutes at 3.6 cm and
109 square arcminutes at 6 cm, containing 778 near-infrared detected YSOs and
190 HST-identified proplyds (with significant overlap between those
characterizations). We detected radio emission from 175 compact radio sources
in the ONC, including 26 sources that were detected for the first time at these
wavelengths. For each detected source we fit a simple free-free and dust
emission model to characterize the radio emission. We extrapolate the free-free
emission spectrum model for each source to ALMA bands to illustrate how these
measurements could be used to correctly measure protoplanetary disk dust masses
from sub-millimeter flux measurements. Finally, we compare the fluxes measured
in this survey with previously measured fluxes for our targets, as well as four
separate epochs of 1.3 cm data, to search for and quantify variability of our
sources.Comment: 13 pages, 6 figures, 4 tables, ApJ, in pres
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