172 research outputs found
Housing and Homicide
In the 1990s, homicide and violent crime dropped dramatically in New York City but not in Chicago. No single factor can fully explain the reasons for Chicago's persistently high rates of violence. Our data suggest Chicago's homicide rate stayed high while New York City's dropped because of: 1) Continuing disputes over drug markets by Chicago's institutionalized gangs; 2) Police tactics that fractured gang leadership; and 3) Surprisingly, displacement caused by the demolition of public housing Our studies have concluded that a city's housing policy is one crucial component in any effective effort to reduce violence
N=(1,1) super Yang--Mills theory in 1+1 dimensions at finite temperature
We present a formulation of N=(1,1) super Yang-Mills theory in 1+1 dimensions
at finite temperature. The partition function is constructed by finding a
numerical approximation to the entire spectrum. We solve numerically for the
spectrum using Supersymmetric Discrete Light-Cone Quantization (SDLCQ) in the
large-N_c approximation and calculate the density of states. We find that the
density of states grows exponentially and the theory has a Hagedorn
temperature, which we extract. We find that the Hagedorn temperature at
infinite resolution is slightly less than one in units of (g^(2) N_c/pi)^(1/2).
We use the density of states to also calculate a standard set of thermodynamic
functions below the Hagedorn temperature. In this temperature range, we find
that the thermodynamics is dominated by the massless states of the theory.Comment: 16 pages, 8 eps figures, LaTe
Paramaterizations of inclusive cross sections for pion production in proton-proton collisions. II. Comparison to new data
A set of new, precise data have recently been made available by the NA49
collaboration for charged pion production in proton-proton and proton-Carbon
reactions at 158 GeV. The current paper compares this new data to five
currently available arithmetic parameterizations. Although a precise fit is not
expected, two of the parameterizations do not work very well but the other
three are able to provide a moderately good, but not precise fit to the
proton-proton data. The best two of these three parameterizations are scaled to
the proton-Carbon data and again provide a moderately good, but not precise
fit.Comment: 11 pages, 13 figures, Accepted for publication in Physical Review
Deep-Inelastic Final States in a Space-Time Description of Shower Development and Hadronization
We extend a quantum kinetic approach to the description of hadronic showers
in space, time and momentum space to deep-inelastic collisions, with
particular reference to experiments at HERA. We follow the history of hard
scattering events back to the initial hadronic state and forward to the
formation of colour-singlet pre-hadronic clusters and their decays into
hadrons. The time evolution of the space-like initial-state shower and the
time-like secondary partons are treated similarly, and cluster formation is
treated using a spatial criterion motivated by confinement and a
non-perturbative model for hadronization. We calculate the time evolution of
particle distributions in rapidity, transverse and longitudinal space. We also
compare the transverse hadronic energy flow and the distribution of observed
hadronic masses with experimental data from HERA, and find encouraging results.
The techniques developed in this paper may be applied in the future to more
complicated processes such as eA, pp, pA and AA collisions.Comment: 44 pages plus 14 postscript figure
Initial Results from the LIGO Newtonian Calibrator
The precise calibration of the strain readout of the LIGO gravitational wave
observatories is paramount to the accurate interpretation of gravitational wave
events. This calibration is traditionally done by imparting a known force on
the test masses of the observatory via radiation pressure. Here we describe the
implementation of an alternative calibration scheme: the Newtonian Calibrator.
This system uses a rotor consisting of both quadrupole and hexapole mass
distributions to apply a time-varying gravitational force on one of the
observatory's test masses. The force produced by this rotor can be predicted to
relative uncertainty and is well-resolved in the readout of the
observatory. This system currently acts as a cross-check of the existing
absolute calibration system
Space, Time and Color in Hadron Production Via e+e- -> Z0 and e+e- -> W+W-
The time-evolution of jets in hadronic e+e- events at LEP is investigated in
both position- and momentum-space, with emphasis on effects due to color flow
and particle correlations. We address dynamical aspects of the four
simultanously-evolving, cross-talking parton cascades that appear in the
reaction e+e- -> gamma/Z0 -> W+W- -> q1 q~2 q3 q~4, and compare with the
familiar two-parton cascades in e+e- -> Z0 -> q1 q~2. We use a QCD statistical
transport approach, in which the multiparticle final state is treated as an
evolving mixture of partons and hadrons, whose proportions are controlled by
their local space-time geography via standard perturbative QCD parton shower
evolution and a phenomenological model for non-perturbative parton-cluster
formation followed by cluster decays into hadrons. Our numerical simulations
exhibit a characteristic `inside-outside' evolution simultanously in position
and momentum space. We compare three different model treatments of color flow,
and find large effects due to cluster formation by the combination of partons
from different W parents. In particular, we find in our preferred model a shift
of several hundred MeV in the apparent mass of the W, which is considerably
larger than in previous model calculations. This suggests that the
determination of the W mass at LEP2 may turn out to be a sensitive probe of
spatial correlations and hadronization dynamics.Comment: 52 pages, latex, 18 figures as uu-encoded postscript fil
Stress from Nucleotide Depletion Activates the Transcriptional Regulator HEXIM1 to Suppress Melanoma
Studying cancer metabolism gives insight into tumorigenic survival mechanisms and susceptibilities. In melanoma, we identify HEXIM1, a transcription elongation regulator, as a melanoma tumor suppressor that responds to nucleotide stress. HEXIM1 expression is low in melanoma. Its overexpression in a zebrafish melanoma model suppresses cancer formation, while its inactivation accelerates tumor onset in vivo. Knockdown of HEXIM1 rescues zebrafish neural crest defects and human melanoma proliferation defects that arise from nucleotide depletion. Under nucleotide stress, HEXIM1 is induced to form an inhibitory complex with P-TEFb, the kinase that initiates transcription elongation, to inhibit elongation at tumorigenic genes. The resulting alteration in gene expression also causes anti-tumorigenic RNAs to bind to and be stabilized by HEXIM1. HEXIM1 plays an important role in inhibiting cancer cell-specific gene transcription while also facilitating anti-cancer gene expression. Our study reveals an important role for HEXIM1 in coupling nucleotide metabolism with transcriptional regulation in melanoma
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The TIGGE project and its achievements
TIGGE was a major component of the THORPEX (The Observing System Research and Predictability Experiment) research program, whose aim is to accelerate improvements in forecasting high-impact weather. By providing ensemble prediction data from leading operational forecast centers, TIGGE has enhanced collaboration between the research and operational meteorological communities and enabled research studies on a wide range of topics.
The paper covers the objective evaluation of the TIGGE data. For a range of forecast parameters, it is shown to be beneficial to combine ensembles from several data providers in a Multi-model Grand Ensemble. Alternative methods to correct systematic errors, including the use of reforecast data, are also discussed.
TIGGE data have been used for a range of research studies on predictability and dynamical processes. Tropical cyclones are the most destructive weather systems in the world, and are a focus of multi-model ensemble research. Their extra-tropical transition also has a major impact on skill of mid-latitude forecasts. We also review how TIGGE has added to our understanding of the dynamics of extra-tropical cyclones and storm tracks.
Although TIGGE is a research project, it has proved invaluable for the development of products for future operational forecasting. Examples include the forecasting of tropical cyclone tracks, heavy rainfall, strong winds, and flood prediction through coupling hydrological models to ensembles.
Finally the paper considers the legacy of TIGGE. We discuss the priorities and key issues in predictability and ensemble forecasting, including the new opportunities of convective-scale ensembles, links with ensemble data assimilation methods, and extension of the range of useful forecast skill
Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas
This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing
molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin
Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context
Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts
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