8,385 research outputs found
Can Neuroscience Help Predict Future Antisocial Behavior?
Part I of this Article reviews the tools currently available to predict antisocial behavior. Part II discusses legal precedent regarding the use of, and challenges to, various prediction methods. Part III introduces recent neuroscience work in this area and reviews two studies that have successfully used neuroimaging techniques to predict recidivism. Part IV discusses some criticisms that are commonly levied against the various prediction methods and highlights the disparity between the attitudes of the scientific and legal communities toward risk assessment generally and neuroscience specifically. Lastly, Part V explains why neuroscience methods will likely continue to help inform and, ideally, improve the tools we use to help assess, understand, and predict human behavior
Investigation of LANDSAT follow-on thematic mapper spatial, radiometric and spectral resolution
The author has identified the following significant results. Fine resolution M7 multispectral scanner data collected during the Corn Blight Watch Experiment in 1971 served as the basis for this study. Different locations and times of year were studied. Definite improvement using 30-40 meter spatial resolution over present LANDSAT 1 resolution and over 50-60 meter resolution was observed, using crop area mensuration as the measure. Simulation studies carried out to extrapolate the empirical results to a range of field size distributions confirmed this effect, showing the improvement to be most pronounced for field sizes of 1-4 hectares. Radiometric sensitivity study showed significant degradation of crop classification accuracy immediately upon relaxation from the nominally specified values of 0.5% noise equivalent reflectance. This was especially the case for data which were spectrally similar such as that collected early in the growing season and also when attempting to accomplish crop stress detection
Spectro-Morphology of Galaxies
We present a quantitative method to classify galaxies, based on
multi-wavelength data and elaborated from the properties of nearby galaxies.
Our objective is to define an evolutionary method that can be used for low and
high redshift objects. We estimate the concentration of light (C) at the galaxy
center and the 180 degree-rotational asymmetry (A), computed at several
wavelengths, from ultraviolet (UV) to I-band. The variation of the indices of
concentration and asymmetry with the wavelength reflects the proportion and the
distribution of young and old stellar populations in galaxies. In general C is
found to decrease from optical to UV, and A is found to increase from optical
to UV: the patchy appearance of galaxies in UV with no bulge is often very
different from their counterpart at optical wavelengths, with prominent bulges
and more regular disks. The variation of C and A with the wavelength is
quantified. By this way, we are able to distinguish five types of galaxies that
we call spectro-morphological types: compact, ringed, spiral, irregular and
central-starburst galaxies, which can be differentiated by the repartition of
their stellar populations. We discuss in detail the morphology of galaxies of
the sample, and describe the morphological characteristics of each
spectro-morphological type. We apply spectro-morphology to three objects at a
redshift z=1 in the Hubble Deep Field North, that gives encouraging results for
applications to large samples of high-redshift galaxies. This method of
morphological classification could be used to study the evolution of the
morphology with the redshift and is expected to bring observational constraints
on scenarios of galaxy evolution.Comment: Accepted for publication in Astronomy & Astrophysic
Development of a global model for atmospheric backscatter at CO2 wavelengths
The variation of the aerosol backscattering at 10.6 micrometers within the free troposphere was investigated and a model to describe this variation was developed. The analysis combines theoretical modeling with the results contained within three independent data sets. The data sets used were obtained by the SAGE I/SAM II satellite experiments, the GAMETAG flight series, and by direct backscatter measurements. The theoretical work includes use of a bimodal, two component aerosol model, and the study of the microphysical and associated optical changes occurring within an aerosol plume. A consistent picture is obtained that describes the variation of the aerosol backscattering function in the free troposphere with altitude, latitude, and season
Provably Secure Experimental Quantum Bit-String Generation
Coin tossing is a cryptographic task in which two parties who do not trust
each other aim to generate a common random bit. Using classical communication
this is impossible, but non trivial coin tossing is possible using quantum
communication. Here we consider the case when the parties do not want to toss a
single coin, but many. This is called bit string generation. We report the
experimental generation of strings of coins which are provably more random than
achievable using classical communication. The experiment is based on the ``plug
and play'' scheme developed for quantum cryptography, and therefore well suited
for long distance quantum communication.Comment: 4 pages, 3 figures. Submitted to Phys. Rev. Lett. A complete security
analysis for the experiment is given in quant-ph/040812
Secure quantum signatures using insecure quantum channels
Digital signatures are widely used in modern communication to guarantee authenticity and transferability of messages. The security of currently used classical schemes relies on computational assumptions. We present a quantum signature scheme that does not require trusted quantum channels. We prove that it is unconditionally secure against the most general coherent attacks, and show that it requires the transmission of significantly fewer quantum states than previous schemes. We also show that the quantum channel noise threshold for our scheme is less strict than for distilling a secure key using quantum key distribution. This shows that “direct” quantum signature schemes can be preferable to signature schemes relying on secret shared keys generated using quantum key distribution.This work was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) under EP/G009821/1 and EP/K022717/1. P.W. gratefully acknowledges support from the COST Action MP1006. A.K. was partially supported by a grant from FQXi and by Perimeter Institute for Theoretical Physics. Research at Perimeter Institute is supported by the Government of Canada through Industry Canada and by the Province of Ontario through the Ministry of Research and Innovation.This is the author accepted manuscript. The final version is available from the American Physical Society via http://dx.doi.org/10.1103/PhysRevA.93.03232
- …