4,269 research outputs found
The Infati Data
The ability to perform meaningful empirical studies is of essence in research
in spatio-temporal query processing. Such studies are often necessary to gain
detailed insight into the functional and performance characteristics of
proposals for new query processing techniques.
We present a collection of spatio-temporal data, collected during an
intelligent speed adaptation project, termed INFATI, in which some two dozen
cars equipped with GPS receivers and logging equipment took part. We describe
how the data was collected and how it was "modified" to afford the drivers some
degree of anonymity.
We also present the road network in which the cars were moving during data
collection.
The GPS data is publicly available for non-commercial purposes. It is our
hope that this resource will help the spatio-temporal research community in its
efforts to develop new and better query processing techniques
CARGO PREFERENCE LEGISLATION, AGRICULTURAL EXPORTS, AND THE FUTURE OF THE DULUTH-SUPERIOR ECONOMY: A LEGISLATIVE HISTORY AND ECONOMIC ANALYSIS
Community/Rural/Urban Development, International Relations/Trade,
A deep dive: Chandra observations of the NGC 4839 group falling into the Coma cluster
Cosmological simulations of structure formation predict that galaxy clusters
continue to grow and evolve through ongoing mergers with group-scale systems.
During these merging events, the ram pressure applied by the intracluster
medium acts to strip the gas from the infalling groups, forming large tails of
stripped gas, which eventually become part of the main cluster. In this work,
we present a detailed analysis of our new deep Chandra observations of the NGC
4839 group falling into the nearby Coma cluster, providing a unique opportunity
to explore the way galaxy clusters in the local universe continue to grow. Our
analysis reveals a cold front feature at the leading head of the group,
preceded by a bow shock of hot gas in front with a Mach number of .
The power spectrum of surface brightness fluctuations in the tail shows that
the slope gets less steep as the distance from the leading head increases,
changing from at the inner part of the tail to
at the outermost part of the tail. These values are
shallower than the slope of the Kolmogorov 2D power spectrum, indicating that
thermal conduction is being suppressed throughout the tail, enabling long-lived
small-scale turbulence, which would typically be washed out if thermal
conduction was not inhibited. The characteristic amplitude of surface
brightness fluctuations in the tail suggests a mild level of turbulence with a
Mach number in the range of 0.1-0.5, agreeing with that found for the infalling
group in Abell 2142.Comment: 10 pages, 10 figures, 3 tables. Accepted for publication in MNRA
Coldâpoolâdriven convective initiation: using causal graph analysis to determine what convectionâpermitting models are missing
Coldâpoolâdriven convective initiation is investigated in highâresolution, convectionâpermitting simulations with a focus on the diurnal cycle and organization of convection and the sensitivity to grid size. Simulations of four different days over Germany were performed using the ICONâLEM model with grid sizes from 156 to 625âm. In these simulations, we identify cold pools, coldâpool boundaries and initiated convection. Convection is triggered much more efficiently in the vicinity of cold pools than in other regions and can provide as much as 50% of total convective initiation, in particular in the late afternoon. By comparing different model resolutions, we find that cold pools are more frequent, smaller and less intense in lowerâresolution simulations. Furthermore, their gust fronts are weaker and less likely to trigger new convection. To identify how model resolution affects this triggering probability, we use a linear causal graph analysis. In doing so, we postulate a graph structure with potential causal pathways and then apply multiâlinear regression accordingly. We find a dominant, systematic effect: reducing grid sizes directly reduces upward mass flux at the gust front, which causes weaker triggering probabilities. These findings are expected to be even more relevant for kmâscale, numerical weather prediction models. We thus expect that a better representation of coldâpoolâdriven convective initiation will improve forecasts of convective precipitation
The thermal conductivity reduction in HgTe/CdTe superlattices
The techniques used previously to calculate the three-fold thermal
conductivity reduction due to phonon dispersion in GaAs/AlAs superlattices
(SLs) are applied to HgTe/CdTe SLs. The reduction factor is approximately the
same, indicating that this SL may be applicable both as a photodetector and a
thermoelectric cooler.Comment: 5 pages, 2 figures; to be published in Journal of Applied Physic
Optical Investigations on Plasma Temperature Estimation in a Model Spark Gap for Surge Currents
In this experimental investigation optical emission spectroscopy is used to characterize the radiation of the plasma in a spark gap during surge. DiïŹerent approaches are used, compared and discussed in order to estimate plasma temperatures. The measurements were carried out in a narrow gap arrangement based on spark gap technology. This model is tested using 8/20â”s surge currents according to the IEC 62475 with amplitudes of 5âkA and 11âkA
Oxidative stress, NADPH oxidases, and arteries
Atherosclerosis and its major complications âmyocardial infarction and strokeâ remain major causes of death and disability in the United States and world-wide. Indeed, with dramatic increases in obesity and diabetes mellitus, the prevalence and public health impact of cardiovascular diseases (CVD) will likely remain high. Major advances have been made in development of new therapies to reduce the incidence of atherosclerosis and CVD, in particular for treatment of hypercholesterolemia and hypertension. Oxidative stress is the common mechanistic link for many CVD risk factors. However, only recently have the tools existed to study the interface between oxidative stress and CVD in animal models. The most important source of reactive oxygen species (and hence oxidative stress) in vascular cells are the multiple forms of enzymes nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase). Recently published and emerging studies now clearly establish that: 1) NADPH oxidases are of critical importance in atherosclerosis and hypertension in animal models; 2) given the tissue-specific expression of key components of NADPH oxidase, it may be possible to target vascular oxidative stress for prevention of CVD
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Cervical cancer in Tanzania: A systematic review of current challenges in six domains.
Cervical cancer is the most common cancer in Tanzania. After excluding human immunodeficiency virus, lower respiratory infections, malaria, diarrheal diseases, and tuberculosis, cervical cancer kills more women than any other form of illness in the country. Unfortunately, Tanzania has a low doctor-to-patient ratio (1:50,000) and nearly 7000 women die each year from this disease. The clinical problem is further magnified by the country\u27s lack of resources and prevailing poverty, sporadic cervical cancer screening, prevalence of high-risk oncogenic human papillomavirus subtypes, and relatively high rates of human immunodeficiency virus co-infection. In recent years, addressing the cervical cancer problem has become a priority for the Tanzanian government. In this systematic review of 39 peer-reviewed publications that appeared in the PubMed/MEDLINE (NCBI) database from 2013 to 2018, we synthesize the growing body of literature to capture current trends in Tanzania\u27s evolving cervical cancer landscape. Six domains were identified, including risk factors, primary prevention, barriers to screening, treatment, healthcare worker education, and sustainability. In addition to traditional risk factors associated with sexual behavior, acetowhite changes observed during visual inspection of the cervix with acetic acid, lower education, rural setting, and HIV positivity also have a noteworthy clinical impact
Yellow Fever and the Emotional Consequences of Untreatable Epidemic Disease
Yellow fever terrorized communities in tropical and urban settings during its height in the nineteenth-century American south. Carried by Aedes aegypti mosquitoes, which breed in stagnant water, the virus infects humans fervently and is most known for its symptoms of jaundice and vomito negro, a dark vomit of coagulated blood. During the near-annual outbreaks of yellow fever, caregivers struggled to cope with the emotional consequences of failing medicine, sometimes leaving behind clues to their confusion in treating the disease and offering salient reflections on their inadequacies. The disease ravaged the Gulf region for decades. Records of the health workersâ feelings of futility reflect their questions of what to do for others and what to do for themselves, offering a new perspective on yellow-fever scholarship and insight into contemporary clinical practice and research.
Quantum simulations of the superfluid-insulator transition for two-dimensional, disordered, hard-core bosons
We introduce two novel quantum Monte Carlo methods and employ them to study
the superfluid-insulator transition in a two-dimensional system of hard-core
bosons. One of the methods is appropriate for zero temperature and is based
upon Green's function Monte Carlo; the other is a finite-temperature world-line
cluster algorithm. In each case we find that the dynamical exponent is
consistent with the theoretical prediction of by Fisher and co-workers.Comment: Revtex, 10 pages, 3 figures (postscript files attached at end,
separated by %%%%%% Fig # %%%%%, where # is 1-3). LA-UR-94-270
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