265 research outputs found
The Political Economy of Female Violent Street Crime
Our research has led us to the conclusion that women in New York City are becoming more and more likely to involve themselves in violent street crimes. This essay analyzes the developing role of women in violent street crime and poses a model, based on both historical analysis and empirical research, to explain the participation of women in violent street crimes in the 1980s
The use of heat pipes to prevent ice formation on highway bridge decks
Sufficient heat can be transported from the surrounding ground to a bridge deck by heat pipes to both reduce the number of freeze-thaw cycles and to reduce the time during which the surface is below freezing. In a computer model of the thermal response of a bridge during a sample month, the use of heat pipes spaced six inches apart reduced the number of freeze-thaw cycles by 58% and the time that the surface was below freezing by 87%. While even higher performance is possible, economic and structural constraints will certianly preclude the elimination of all freezing. A screen covered groove heat pipe using ammonia as a working fluid appears to yield the best performance. Computer models are presented to analyse the performance of such heat pipes and to predict the thermal response of a highway bridge with heat pipes to either idealized or actual meteorological conditions. Recommendations are made for further work.N
Investigating MMM Ponzi scheme on Bitcoin
Cybercriminals exploit cryptocurrencies to carry out illicit activities. In
this paper, we focus on Ponzi schemes that operate on Bitcoin and perform an
in-depth analysis of MMM, one of the oldest and most popular Ponzi schemes.
Based on 423K transactions involving 16K addresses, we show that: (1) Starting
Sep 2014, the scheme goes through three phases over three years. At its peak,
MMM circulated more than 150M dollars a day, after which it collapsed by the
end of Jun 2016. (2) There is a high income inequality between MMM members,
with the daily Gini index reaching more than 0.9. The scheme also exhibits a
zero-sum investment model, in which one member's loss is another member's gain.
The percentage of victims who never made any profit has grown from 0% to 41% in
five months, during which the top-earning scammer has made 765K dollars in
profit. (3) The scheme has a global reach with 80 different member countries
but a highly-asymmetrical flow of money between them. While India and Indonesia
have the largest pairwise flow in MMM, members in Indonesia have received 12x
more money than they have sent to their counterparts in India
Inactivation of c-Cbl Reverses Neonatal Lethality and T Cell Developmental Arrest of SLP-76–deficient Mice
c-Cbl is an adaptor protein that negatively regulates signal transduction events involved in thymic-positive selection. To further characterize the function of c-Cbl in T cell development, we analyzed the effect of c-Cbl inactivation in mice deficient in the scaffolding molecule SLP-76. SLP-76–deficient mice show a high frequency of neonatal lethality; and in surviving mice, T cell development is blocked at the DN3 stage. Inactivation of c-cbl completely reversed the neonatal lethality seen in SLP-76–deficient mice and partially reversed the T cell development arrest in these mice. SLP-76−/− Cbl−/− mice exhibited marked expansion of polarized T helper type (Th)1 and Th2 cell peripheral CD4+ T cells, lymphoid infiltrates of parenchymal organs, and premature death. This rescue of T cell development is T cell receptor dependent because it does not occur in recombination activating gene 2−/− SLP-76−/− Cbl−/− triple knockout mice. Analysis of the signal transduction properties of SLP-76−/− Cbl−/− T cells reveals a novel SLP-76– and linker for activation of T cells–independent pathway of extracellular signal–regulated kinase activation, which is normally down-regulated by c-Cbl
Ribp, a Novel Rlk/Txk- and Itk-Binding Adaptor Protein That Regulates T Cell Activation
A novel T cell–specific adaptor protein, RIBP, was identified based on its ability to bind Rlk/Txk in a yeast two-hybrid screen of a mouse T cell lymphoma library. RIBP was also found to interact with a related member of the Tec family of tyrosine kinases, Itk. Expression of RIBP is restricted to T and natural killer cells and is upregulated substantially after T cell activation. RIBP-disrupted knockout mice displayed apparently normal T cell development. However, proliferation of RIBP-deficient T cells in response to T cell receptor (TCR)-mediated activation was significantly impaired. Furthermore, these activated T cells were defective in the production of interleukin (IL)-2 and interferon γ, but not IL-4. These data suggest that RIBP plays an important role in TCR-mediated signal transduction pathways and that its binding to Itk and Rlk/Txk may regulate T cell differentiation
Overview of the Kepler Science Processing Pipeline
The Kepler Mission Science Operations Center (SOC) performs several critical
functions including managing the ~156,000 target stars, associated target
tables, science data compression tables and parameters, as well as processing
the raw photometric data downlinked from the spacecraft each month. The raw
data are first calibrated at the pixel level to correct for bias, smear induced
by a shutterless readout, and other detector and electronic effects. A
background sky flux is estimated from ~4500 pixels on each of the 84 CCD
readout channels, and simple aperture photometry is performed on an optimal
aperture for each star. Ancillary engineering data and diagnostic information
extracted from the science data are used to remove systematic errors in the
flux time series that are correlated with these data prior to searching for
signatures of transiting planets with a wavelet-based, adaptive matched filter.
Stars with signatures exceeding 7.1 sigma are subjected to a suite of
statistical tests including an examination of each star's centroid motion to
reject false positives caused by background eclipsing binaries. Physical
parameters for each planetary candidate are fitted to the transit signature,
and signatures of additional transiting planets are sought in the residual
light curve. The pipeline is operational, finding planetary signatures and
providing robust eliminations of false positives.Comment: 8 pages, 3 figure
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
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