1,072 research outputs found
Community rotorcraft air transportation benefits and opportunities
Information about rotorcraft that will assist community planners in assessing and planning for the use of rotorcraft transportation in their communities is provided. Information useful to helicopter researchers, manufacturers, and operators concerning helicopter opportunities and benefits is also given. Three primary topics are discussed: the current status and future projections of rotorcraft technology, and the comparison of that technology with other transportation vehicles; the community benefits of promising rotorcraft transportation opportunities; and the integration and interfacing considerations between rotorcraft and other transportation vehicles. Helicopter applications in a number of business and public service fields are examined in various geographical settings
An infrared integrated optic astronomical beam combiner for stellar interferometry at 3-4 microns
Integrated-optic, astronomical, two-beam and three-beam, interferometric
combiners have been designed and fabricated for operation in the L band (3 - 4
microns) for the first time. The devices have been realized in
titanium-indiffused, x-cut lithium niobate substrates, and on-chip
electro-optic fringe scanning has been demonstrated. White light fringes were
produced in the laboratory using the two-beam combiner integrated with an
on-chip Y-splitter.Comment: This paper was published in Optics Express and is made available as
an electronic reprint with the permission of OSA. The paper can be found at
the following URL on the OSA website: http://www.opticsinfobase.org/oe.
Systematic or multiple reproduction or distribution to multiple locations via
electronic or other means is prohibited and is subject to penalties under la
Synchrotron radiation from a charge moving along a helical orbit inside a dielectric cylinder
The radiation emitted by a charged particle moving along a helical orbit
inside a dielectric cylinder immersed into a homogeneous medium is
investigated. Expressions are derived for the electromagnetic potentials,
electric and magnetic fields, and for the spectral-angular distribution of
radiation in the exterior medium. It is shown that under the Cherenkov
condition for dielectric permittivity of the cylinder and the velocity of the
particle image on the cylinder surface, strong narrow peaks are present in the
angular distribution for the number of radiated quanta. At these peaks the
radiated energy exceeds the corresponding quantity for a homogeneous medium by
some orders of magnitude. The results of numerical calculations for the angular
distribution of radiated quanta are presented and they are compared with the
corresponding quantities for radiation in a homogeneous medium. The special
case of relativistic charged particle motion along the direction of the
cylinder axis with non-relativistic transverse velocity (helical undulator) is
considered in detail. Various regimes for the undulator parameter are
discussed. It is shown that the presence of the cylinder can increase
essentially the radiation intensity.Comment: 18 pages, 8 EPS figure
Neodymium‐doped glass channel waveguide laser containing an integrated distributed Bragg reflector
An integrated, distributed Bragg reflector laser in a Nd‐doped, glass, channel waveguide is reported for the first time. The waveguide is fabricated using Ag+ thermal ion exchange in a soda‐lime‐silicate‐glass containing 2% Nd2O3 by weight. The distributed Bragg reflector grating is produced holographically in photoresist and then etched into the waveguide using argon ion milling. The device lases in a single longitudinal mode with a pump threshold of 50 mW and a slope efficiency of 1%.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69747/2/APPLAB-61-23-2744-1.pd
Inherited coding variants at the CDKN2A locus influence susceptibility to acute lymphoblastic leukaemia in children
There is increasing evidence from genome-wide association studies for a strong inherited genetic basis of susceptibility to acute lymphoblastic leukaemia (ALL) in children, yet the effects of protein-coding variants on ALL risk have not been systematically evaluated. Here we show a missense variant in CDKN2A associated with the development of ALL at genome-wide significance (rs3731249, P=9.4 × 10(-23), odds ratio=2.23). Functional studies indicate that this hypomorphic variant results in reduced tumour suppressor function of p16(INK4A), increases the susceptibility to leukaemic transformation of haematopoietic progenitor cells, and is preferentially retained in ALL tumour cells. Resequencing the CDKN2A-CDKN2B locus in 2,407 childhood ALL cases reveals 19 additional putative functional germline variants. These results provide direct functional evidence for the influence of inherited genetic variation on ALL risk, highlighting the important and complex roles of CDKN2A-CDKN2B tumour suppressors in leukaemogenesis.Heng Xu, Hui Zhang, Wenjian Yang, Rachita Yadav, Alanna C. Morrison, Maoxiang Qian, Meenakshi Devidas, Yu Liu, Virginia Perez-Andreu, Xujie Zhao, Julie M. Gastier-Foster, Philip J. Lupo, Geoff Neale, Elizabeth Raetz, Eric Larsen, W. Paul Bowman, William L. Carroll, Naomi Winick, Richard Williams, Torben Hansen, Jens-Christian Holm, Elaine Mardis, Robert Fulton, Ching-Hon Pui, Jinghui Zhang, Charles G. Mullighan, William E. Evans, Stephen P. Hunger, Ramneek Gupta, Kjeld Schmiegelow, Mignon L. Loh, Mary V. Relling, Jun J. Yan
Imprisonment and internment: Comparing penal facilities North and South
Recent references to the ‘warehouse prison’ in the United States and the prisión-depósito in Latin America seem to indicate that penal confinement in the western hemisphere
has converged on a similar model. However, this article suggests otherwise. It contrasts penal facilities in North America and Latin America in terms of six interrelated aspects: regimentation; surveillance; isolation; supervision; accountability; and formalization. Quantitatively, control in North American penal facilities is assiduous (unceasing, persistent and intrusive), while in Latin America it is perfunctory (sporadic, indifferent and cursory). Qualitatively, North American penal facilities produce imprisonment (which enacts penal intervention through confinement), while in Latin America they produce internment (which enacts penal intervention through release). Closely entwined with this qualitative difference are distinct practices of judicial involvement in sentencing and penal supervision. Those practices, and the cultural and political factors that underpin them, represent an interesting starting point for the explanation of the contrasting nature of imprisonment and internment
Offender rehabilitation : a normative framework for forensic psychologists
Community protection from offenders is addressed through punishment, deterrence, incapacitation, and/or rehabilitation. The current public policy debate about community protection refers to community rights as opposed to offender rights as if the two are mutually exclusive. However, in this article it will be argued that offender rehabilitation can enhance community protection if it addresses community rights and offender rights. The author proposes a normative framework to guide forensic psychologists in offender rehabilitation. The normative framework considers psychological theory—the risk-need model to address community rights and the good lives model to address offender rights. However, forensic psychologists operate within the context of the criminal justice system and so legal theory will also be considered. Therapeutic jurisprudence can balance community rights and offender rights within a human rights perspective. The proposed normative framework guides forensic psychologists in the assessment of risk, the treatment of need, and the management of readiness in balancing community rights and offender rights. Within a human rights perspective, forensic psychologists have a duty to provide offenders with the opportunity to make autonomous decisions about whether to accept or reject rehabilitation. <br /
Phase response measurement technique for waveguide grating filters
A simple interferometric technique is described which can be used to accurately measure the phase response of waveguide grating filters. A narrowband, tunable Ti:sapphire laser is used in a Michelson interferometer configuration, where light reflected from a waveguide grating filter is combined with a reference beam. The intensity of the combined beams is measured as the wavelength of the Ti:sapphire laser is tuned. The measured intensity exhibits a quasisinusoidal wavelength dependence, from which the phase response of the filter can be deduced. This method is successfully demonstrated using both an integrated optic waveguide grating filter and a bulk grating pair. © 1995 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69947/2/APPLAB-66-17-2168-1.pd
Observations of Infrared Radiative Cooling in the Thermosphere on Daily to Multiyear Timescales from the TIMED/SABER Instrument
We present observations of the infrared radiative cooling by carbon dioxide (CO2) and nitric oxide (NO) in Earth s thermosphere. These data have been taken over a period of 7 years by the SABER instrument on the NASA TIMED satellite and are the dominant radiative cooling mechanisms for the thermosphere. From the SABER observations we derive vertical profiles of radiative cooling rates (W/cu m), radiative fluxes (W/sq m), and radiated power (W). In the period from January 2002 through January 2009 we observe a large decrease in the cooling rates, fluxes, and power consistent with the declining phase of solar cycle. The power radiated by NO during 2008 when the Sun exhibited few sunspots was nearly one order of magnitude smaller than the peak power observed shortly after the mission began. Substantial short-term variability in the infrared emissions is also observed throughout the entire mission duration. Radiative cooling rates and radiative fluxes from NO exhibit fundamentally different latitude dependence than do those from CO2, with the NO fluxes and cooling rates being largest at high latitudes and polar regions. The cooling rates are shown to be derived relatively independent of the collisional and radiative processes that drive the departure from local thermodynamic equilibrium (LTE) in the CO2 15 m and the NO 5.3 m vibration-rotation bands. The observed NO and CO2 cooling rates have been compiled into a separate dataset and represent a climate data record that is available for use in assessments of radiative cooling in upper atmosphere general circulation models
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