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Evaluating safety at Oregonâs isolated, high-speed, signalized intersections
Isolated approaches at signalized intersections with posted speed limits of 45 mph or greater generally experience large numbers of rear-end and angle collisions. A combination of less attentive drivers, high operating speeds, and less than ideal intersection characteristics can result in crash frequencies well above expected rates. A number of treatment options are available to target specific safety concerns at intersections, but it can be difficult or time-consuming to determine when an intersection is experiencing abnormal crash trends. The Oregon Department of Transportation (ODOT) does not currently have a system in place for evaluating safety at isolated, high-speed, signalized intersections (IHSSIs). This thesis describes the development of a method for efficiently evaluating safety and determining potential treatment options for IHSSIs. Specifically, this method identifies data collection requirements, determines expected crash frequencies based on intersection configuration, and provides a list of safety treatment options. This information is packaged into a safety evaluation template to allow for efficient and effective IHSSI evaluations
Continuity of the four-point function of massive -theory above threshold
In this paper we prove that the four-point function of massive
\vp_4^4-theory is continuous as a function of its independent external
momenta when posing the renormalization condition for the (physical) mass
on-shell. The proof is based on integral representations derived inductively
from the perturbative flow equations of the renormalization group. It closes a
longstanding loophole in rigorous renormalization theory in so far as it shows
the feasibility of a physical definition of the renormalized coupling.Comment: 23 pages; to appear in Rev. Math. Physics few corrections, two
explanatory paragraphs adde
Protein intake and outcome of critically ill patients: analysis of a large international database using piece-wise exponential additive mixed models
BACKGROUND Proteins are an essential part of medical nutrition therapy in critically ill patients. Guidelines almost universally recommend a high protein intake without robust evidence supporting its use. METHODS Using a large international database, we modelled associations between the hazard rate of in-hospital death and live hospital discharge (competing risks) and three categories of protein intake (low: 1.2~g/kg per day) during the first 11~days after ICU admission (acute phase). Time-varying cause-specific hazard ratios (HR) were calculated from piece-wise exponential additive mixed models. We used the estimated model to compare five different hypothetical protein diets (an exclusively low protein diet, a standard protein diet administered early (day 1 to 4) or late (day 5 to 11) after ICU admission, and an early or late high protein diet). RESULTS Of 21,100 critically ill patients in the database, 16,489 fulfilled inclusion criteria for the analysis. By day 60, 11,360 (68.9%) patients had been discharged from hospital, 4,192 patients (25.4%) had died in hospital, and 937 patients (5.7%) were still hospitalized. Median daily low protein intake was 0.49~g/kg IQR 0.27-0.66, standard intake 0.99~g/kg IQR 0.89- 1.09, and high intake 1.41~g/kg IQR 1.29-1.60. In comparison with an exclusively low protein diet, a late standard protein diet was associated with a lower hazard of in-hospital death: minimum 0.75 (95{\%} CI 0.64, 0.87), and a higher hazard of live hospital discharge: maximum HR 1.98 (95{\%} CI 1.72, 2.28). Results on hospital discharge, however, were qualitatively changed by a sensitivity analysis. There was no evidence that an early standard or a high protein intake during the acute phase was associated with a further improvement of outcome. CONCLUSIONS Provision of a standard protein intake during the late acute phase may improve outcome compared to an exclusively low protein diet. In unselected critically ill patients, clinical outcome may not be improved by a high protein intake during the acute phase. Study registration ID number ISRCTN17829198
Gap generation in the BCS model with finite range temporal interaction
In the [BCS] paper the theory of superconductivity was developed for the BCS
model, in which the (instantaneous) interaction is only between fermions of
opposite momentum and spin. Such model was analyzed by variational methods,
finding that a superconducting behavior is energetically favorable.
Subsequently it was claimed that in the thermodynamic limit the BCS model is
equivalent to the (exactly solvable) quadratic mean field BCS model; a rigorous
proof of this claim is however still lacking. In this paper we consider the BCS
model with a finite range temporal interaction, and we prove rigorously its
equivalence with the mean field BCS model in the thermodinamic limit if the
range is long enough, by a (uniformly convergent) perturbation expansion about
mean field theory.Comment: 14 page
One-loop Beta Functions for the Orientable Non-commutative Gross-Neveu Model
We compute at the one-loop order the beta-functions for a renormalisable
non-commutative analog of the Gross Neveu model defined on the Moyal plane. The
calculation is performed within the so called x-space formalism. We find that
this non-commutative field theory exhibits asymptotic freedom for any number of
colors. The beta-function for the non-commutative counterpart of the Thirring
model is found to be non vanishing.Comment: 16 pages, 9 figure
Noncommutative Induced Gauge Theory
We consider an external gauge potential minimally coupled to a renormalisable
scalar theory on 4-dimensional Moyal space and compute in position space the
one-loop Yang-Mills-type effective theory generated from the integration over
the scalar field. We find that the gauge invariant effective action involves,
beyond the expected noncommutative version of the pure Yang-Mills action,
additional terms that may be interpreted as the gauge theory counterpart of the
harmonic oscillator term, which for the noncommutative -theory on Moyal
space ensures renormalisability. The expression of a possible candidate for a
renormalisable action for a gauge theory defined on Moyal space is conjectured
and discussed.Comment: 20 pages, 6 figure
Search for non-relativistic Magnetic Monopoles with IceCube
The IceCube Neutrino Observatory is a large Cherenkov detector instrumenting
of Antarctic ice. The detector can be used to search for
signatures of particle physics beyond the Standard Model. Here, we describe the
search for non-relativistic, magnetic monopoles as remnants of the GUT (Grand
Unified Theory) era shortly after the Big Bang. These monopoles may catalyze
the decay of nucleons via the Rubakov-Callan effect with a cross section
suggested to be in the range of to
. In IceCube, the Cherenkov light from nucleon decays
along the monopole trajectory would produce a characteristic hit pattern. This
paper presents the results of an analysis of first data taken from May 2011
until May 2012 with a dedicated slow-particle trigger for DeepCore, a
subdetector of IceCube. A second analysis provides better sensitivity for the
brightest non-relativistic monopoles using data taken from May 2009 until May
2010. In both analyses no monopole signal was observed. For catalysis cross
sections of the flux of non-relativistic
GUT monopoles is constrained up to a level of at a 90% confidence level,
which is three orders of magnitude below the Parker bound. The limits assume a
dominant decay of the proton into a positron and a neutral pion. These results
improve the current best experimental limits by one to two orders of magnitude,
for a wide range of assumed speeds and catalysis cross sections.Comment: 20 pages, 20 figure
Lateral Distribution of Muons in IceCube Cosmic Ray Events
In cosmic ray air showers, the muon lateral separation from the center of the
shower is a measure of the transverse momentum that the muon parent acquired in
the cosmic ray interaction. IceCube has observed cosmic ray interactions that
produce muons laterally separated by up to 400 m from the shower core, a factor
of 6 larger distance than previous measurements. These muons originate in high
pT (> 2 GeV/c) interactions from the incident cosmic ray, or high-energy
secondary interactions. The separation distribution shows a transition to a
power law at large values, indicating the presence of a hard pT component that
can be described by perturbative quantum chromodynamics. However, the rates and
the zenith angle distributions of these events are not well reproduced with the
cosmic ray models tested here, even those that include charm interactions. This
discrepancy may be explained by a larger fraction of kaons and charmed
particles than is currently incorporated in the simulations
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