746 research outputs found
Evaluation of the Michigan TACT Program
This report documents the evaluation of the Michigan Ticketing Aggressive Cars and Trucks (TACT) program. The TACT program was conducted in three 2-week waves in the fall of 2013 near Grand Rapids, Michigan. Comparable sites in southeast Michigan served as a comparison area. The TACT program combined high visibility enforcement with a public information and education (PI&E) campaign focused on unsafe driving behaviors of cars and trucks near each other. An evaluation of the TACT implementation found that that the enforcement and PI&E plans were followed reasonably well. Outcomes in terms of driver behaviors, attitudes, and traffic safety were tested by means of surveys of motorists and truck drivers; an observational study of passing and merging behaviors of passenger cars near large trucks; and analysis of crash data. A before/after with comparison design was used to measure any effect in each outcome. Results indicated that the PI&E messages reached the drivers in the program area. Analysis of the survey data did not identify any statistically significant changes in self-reported behaviors among the drivers in the program area. The proportion of safe passing and merging maneuvers recorded in the observational study were quite high before the program and did not change significantly after the program. A Poisson crash rate model adjusted for over-dispersion and using six-years of monthly crash data from the program and comparison areas was developed. It accounted for traffic volumes, proportion of trucks in the traffic, snowfall and precipitation, and the economy. The crash data analysis did not identify significant effects of the program on crash rates.Michigan Office of Highway Safety Planning, Michigan State Policehttp://deepblue.lib.umich.edu/bitstream/2027.42/109414/1/103138.pd
Prioritizing improvements to truck driver vision
This report presents the results of a three-part study of truck driver exterior vision and its safety consequences. In part one,
crash data are analyzed to document vision-related truck crash issues. About 20% of truck-initiated crashes occur in
configurations in which limitations to truck driver vision may have been an important factor contributing to the crash.
Right-going lane changes and turns account for more than half of these crashes. On average, right-going truck-initiated
crashes are about 4.5 times more likely than left-going crashes. Non-motorists killed in startup and right-turn crashes were
nearly all adults and tend to be older the pedestrians struck in other crash modes, suggesting that near-field truck vision
analyses should focus on adults rather than children. Over half of pedestrians involved in start-up crashes are over age 65.
An experimental study showed that driver performance in detecting lane-change conflicts was directionally consistent with
the findings from the crash data. Drivers took longer to detect conflicts on the right side of the vehicle than on the left. The
longest reaction times were observed when the target vehicle was directly to the right of the cab, suggesting that detecting a
conflict in this area is most difficult for drivers. Drivers also made more errors on the right side of the vehicle, including
several failures to detect a vehicle directly to the right of the cab. Based on these findings, a prioritized set of vision zones
was developed. The highest priority for improvements to driver vision is the area directly to the right of the truck cab. This
area represents the most likely position of a crash partner at the truck driver’s decision point in right lane-change crashes and
is also the pre-crash position of many non-motorists involved in right turn and start up crashes. This report presents a new
approach to evaluating exterior vision from truck cabs. The method differs from previous approaches, e.g., SAE J1750, by
providing an aggregate score that is related to a specific crash-safety issue. The method is based on the visibility of standing
adult pedestrians, and hence addresses the specific problem of pedestrian involvement in start up and right turn crashes. The
experimental paradigm presented in Section 3 also represents a promising approach to evaluating the quality of exterior
vision provided by alternative vision systems. The time drivers require to determine if a conflict exists provides a sensitive
measure of the difficulty of the task. The parallels between the findings of the experimental study and the crash data
analysis support the validity of the experimental approach. This method could be applied to evaluate alternative mirror
systems, camera-based systems, and other technologies that might be developed to address the priorities established in this
report.International Truck and Engine Corporationhttp://deepblue.lib.umich.edu/bitstream/2027.42/83927/1/102737.pd
Probing Unexpected Reactivity in Radiometal Chemistry: Indium-111-Mediated Hydrolysis of Hybrid Cyclen-Hydroxypyridinone Ligands
Chelators based on hydroxypyridinones have utility in
incorporating
radioactive metal ions into diagnostic and therapeutic agents used
in nuclear medicine. Over the course of our hydroxypyridinone studies,
we have prepared two novel chelators, consisting of a cyclen (1,4,7,10-tetraazacyclododecane)
ring bearing two pendant hydroxypyridinone groups, appended via methylene
acetamide motifs at either the 1,4-positions (L1) or 1,7-positions (L2) of the cyclen ring. In radiolabeling reactions of L1 or L2 with the γ-emitting radioisotope, [111In]In3+, we have observed radiometal-mediated hydrolysis of a single
amide group of either L1 or L2. The reaction of either [111In]In3+ or [natIn]In3+ with either L1 or L2, in aqueous alkaline solutions at 80 °C, initially results
in formation of [In(L1)]+ or [In(L2)]+, respectively. Over time, each of these species undergoes In3+-mediated hydrolysis of a single amide group to yield species
in which In3+ remains coordinated to the resultant chelator,
which consists of a cyclen ring bearing a single hydroxypyridinone
group and a single carboxylate group. The reactivity toward hydrolysis
is higher for the L1 complex
compared to that for the L2 complex.
Density functional theory calculations corroborate these experimental
findings and importantly indicate that the activation energy required
for the hydrolysis of L1 is significantly
lower than that required for L2. This is the first reported example of a chelator undergoing radiometal-mediated
hydrolysis to form a radiometalated complex. It is possible that metal-mediated
amide bond cleavage is a source of instability in other radiotracers,
particularly those in which radiometal complexation occurs in aqueous,
basic solutions at high temperatures. This study highlights the importance
of appropriate characterization of radiolabeled products
68Ga-bisphosphonates for the imaging of extraosseous calcification by positron emission tomography
Radiolabelled bisphosphonates (BPs) and [18F]NaF (18F-fluoride) are the two types of radiotracers available to image calcium mineral (e.g. bone), yet only [18F]NaF has been widely explored for the non-invasive molecular imaging of extraosseous calcification (EC) using positron emission tomography (PET) imaging. These two radiotracers bind calcium mineral deposits via different mechanisms, with BPs chelating to calcium ions and thus being non-selective, and [18F]NaF being selective for hydroxyapatite (HAp) which is the main component of bone mineral. Considering that the composition of EC has been reported to include a diverse range of non-HAp calcium minerals, we hypothesised that BPs may be more sensitive for imaging EC due to their ability to bind to both HAp and non-HAp deposits. We report a comparison between the 68Ga-labelled BP tracer [68Ga]Ga-THP-Pam and [18F]NaF for PET imaging in a rat model of EC that develops macro- and microcalcifications in several organs. Macrocalcifications were identified using preclinical computed tomography (CT) and microcalcifications were identified using µCT-based 3D X-ray histology (XRH) on isolated organs ex vivo. The morphological and mineral analysis of individual calcified deposits was performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). PET imaging and ex vivo analysis results demonstrated that while both radiotracers behave similarly for bone imaging, the BP-based radiotracer [68Ga]Ga-THP-Pam was able to detect EC more sensitively in several organs in which the mineral composition departs from that of HAp. Our results strongly suggest that BP-based PET radiotracers such as [68Ga]Ga-THP-Pam may have a particular advantage for the sensitive imaging and early detection of EC by being able to detect a wider array of relevant calcium minerals in vivo than [18F]NaF, and should be evaluated clinically for this purpose
Creating a proof-of-concept climate service to assess future renewable energy mixes in Europe: an overview of the C3S ECEM project
The EU Copernicus Climate Change Service (C3S) European Climatic Energy Mixes (ECEM) has produced, in close collaboration with prospective users, a proof-of-concept climate service, or Demonstrator, designed to enable the energy industry and policy makers assess how well different energy supply mixes in Europe will meet demand, over different time horizons (from seasonal to long-term decadal planning), focusing on the role climate has on the mixes. The concept of C3S ECEM, its methodology and some results are presented here.
The first part focuses on the construction of reference data sets for climate variables based on the ERA-Interim reanalysis. Subsequently, energy variables were created by transforming the bias-adjusted climate variables using a combination of statistical and physically-based models. A comprehensive set of measured energy supply and demand data was also collected, in order to assess the robustness of the conversion to energy variables. Climate and energy data have been produced both for the historical period (1979–2016) and for future projections (from 1981 to 2100, to also include a past reference period, but focusing on the 30 year period 2035–2065). The skill of current seasonal forecast systems for climate and energy variables has also been assessed.
The C3S ECEM project was designed to provide ample opportunities for stakeholders to convey their needs and expectations, and assist in the development of a suitable Demonstrator. This is the tool that collects the output produced by C3S ECEM and presents it in a user-friendly and interactive format, and it therefore constitutes the essence of the C3S ECEM proof-of-concept climate service
Temporal networks of face-to-face human interactions
The ever increasing adoption of mobile technologies and ubiquitous services
allows to sense human behavior at unprecedented levels of details and scale.
Wearable sensors are opening up a new window on human mobility and proximity at
the finest resolution of face-to-face proximity. As a consequence, empirical
data describing social and behavioral networks are acquiring a longitudinal
dimension that brings forth new challenges for analysis and modeling. Here we
review recent work on the representation and analysis of temporal networks of
face-to-face human proximity, based on large-scale datasets collected in the
context of the SocioPatterns collaboration. We show that the raw behavioral
data can be studied at various levels of coarse-graining, which turn out to be
complementary to one another, with each level exposing different features of
the underlying system. We briefly review a generative model of temporal contact
networks that reproduces some statistical observables. Then, we shift our focus
from surface statistical features to dynamical processes on empirical temporal
networks. We discuss how simple dynamical processes can be used as probes to
expose important features of the interaction patterns, such as burstiness and
causal constraints. We show that simulating dynamical processes on empirical
temporal networks can unveil differences between datasets that would otherwise
look statistically similar. Moreover, we argue that, due to the temporal
heterogeneity of human dynamics, in order to investigate the temporal
properties of spreading processes it may be necessary to abandon the notion of
wall-clock time in favour of an intrinsic notion of time for each individual
node, defined in terms of its activity level. We conclude highlighting several
open research questions raised by the nature of the data at hand.Comment: Chapter of the book "Temporal Networks", Springer, 2013. Series:
Understanding Complex Systems. Holme, Petter; Saram\"aki, Jari (Eds.
[89Zr]Oxinate4 for long-term in vivo cell tracking by positron emission tomography
Purpose 111In (typically as [111In]oxinate3) is a gold standard
radiolabel for cell tracking in humans by scintigraphy. A long
half-life positron-emitting radiolabel to serve the same purpose
using positron emission tomography (PET) has long
been sought. We aimed to develop an 89Zr PET tracer for cell
labelling and compare it with [111In]oxinate3 single photon
emission computed tomography (SPECT).
Methods [89Zr]Oxinate4 was synthesised and its uptake and
efflux were measured in vitro in three cell lines and in human
leukocytes. The in vivo biodistribution of eGFP-5T33 murine
myeloma cells labelled using [89Zr]oxinate4 or [111In]oxinate3
was monitored for up to 14 days. 89Zr retention by living
radiolabelled eGFP-positive cells in vivo was monitored by
FACS sorting of liver, spleen and bone marrow cells followed
by gamma counting.
Results Zr labelling was effective in all cell types with yields
comparable with 111In labelling. Retention of 89Zr in cells
in vitro after 24 h was significantly better (range 71 to
>90 %) than 111In (43–52 %). eGFP-5T33 cells in vivo
showed the same early biodistribution whether labelled with
111In or 89Zr (initial pulmonary accumulation followed by
migration to liver, spleen and bone marrow), but later translocation
of radioactivity to kidneys was much greater for 111In.
In liver, spleen and bone marrow at least 92 % of 89Zr
remained associated with eGFP-positive cells after 7 days
in vivo.
Conclusion [89Zr]Oxinate4 offers a potential solution to the
emerging need for a long half-life PET tracer for cell tracking
in vivo and deserves further evaluation of its effects on survival
and behaviour of different cell types
Granisetron vs ondansetron: is it a question of duration of 5-HT3 receptor blockade?
British Journal of Cancer (2002) 86, 1662–1663. DOI: 10.1038/sj/bjc/6600313 www.bjcancer.co
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