1,686 research outputs found
Methods and standards development for three-dimensional mapping of the Antioch Quadrangle, Lake County, Illinois a pilot study
The Pilot Study for the Central Great Lakes Geologic Mapping Coalition (CGLGMC) focused on the Antioch Quadrangle, Lake County, Illinois developing a series of maps and digital products, several protocols for database development and maintenance and field procedures to acquire and integrate drilling and geophysical data from a quadangle area featuring complex glacial geology over a 25,000 year period.U.S. Geological Survey, Central Great Lakes Geologic Mapping CoalitionOpe
Characterizing CDMA downlink feasibility via effective interference
This paper models and analyses downlink power assignment feasibility in Code Division Multiple Access (CDMA) mobile networks. By discretizing the area into small segments, the power requirements are characterized via a matrix representation that separates user and system characteristics. We obtain a closed-form analytical expression of the so-called Perron-Frobenius eigenvalue of that matrix, which provides a quick assessment of the feasibility of the power assignment for each distribution of calls over the segments. Although the obtained relation is non-linear, it basically provides an effective interference characterisation of downlink feasibility. Our results allow for a fast evaluation of outage and blocking probabilities, and enable a quick evaluation of feasibility that may be used for Call Acceptance Control. \u
Screening for Chlamydia trachomatis in Low-Risk Obstetric Patients
Objective: The purpose of this study was to evaluate the prevalence of
Chlamydia trachomatis in our rural obstetric population and assess the appropriateness
of selective vs. universal prenatal screening
Extremes in dune preservation: controls on the completeness of fluvial deposits
Understanding sedimentary preservation underpins our ability to interpret the ancient sedimentary record and reconstruct palaeoenvironments and palaeoclimates. Dune sets are ubiquitous in preserved river deposits and are typically interpreted based on a model that that describes the recurrence of erosion in a vertical sequence, but without consideringspatial variability. However, spatial variability in flow and sediment transport will change the recurrence of erosion, and therefore dune preservation. In order to better understand the limits of these Interpretations and outline the causes of potential variability in preservation potential, this paper reviews existing work and presents new observations of an extreme end-member of dune preservation: ?form-sets?, formed by dunes in which both stoss- and lee- slopes are preserved Intact. These form-sets do not conform to models that are based on the recurrence of erosion, since erosion does not recur in their case, and can therefore be used to evaluate the assumptions that underpin sedimentary preservation. New Ground Penetrating Radar data from the Río Paraná, Argentina, show dune fields that are buried intact within larger scale barforms. These trains of form-sets are up to 300 m in length, are restricted to unit-bar troughs in the upper 5 m of the channel deposits, occur in >5% of the mid-channel bar deposits, show reactivation surfaces, occur in multiple levels, and match the size of average-flow dunes. A review of published accounts of form-sets highlights a diversity of processes that can be envisaged for their formation: i) abandonment after extreme floods, ii) slow burial of abandoned dune forms by cohesive clay in sheltered bar troughs and meander-neck cut-offs, iii) fast burial by mass-movement processes, and iv)climbing of dune sets due to local dominance of deposition over dune migration.Analysis of these new and published accounts of form-sets and their burial processes highlights that form-sets need not be indicative of extreme floods. Instead, form-sets are closely associated with surrounding geomorphology such as river banks, meander-neck cutoffs,and bars because this larger-scale context controls the local sediment budget and the nature of recurrence of erosion. Locally enhanced preservation by the ?extreme? dominance of deposition is further promoted by finer grain sizes and prolonged changes in flow stage. Such conditions are characteristic, although not exclusive, of large lowland rivers such as the Río Paraná. The spatial control on dune preservation is critical: although at-a-point models adequately describe near-horizontal sets of freely migrating dunes in uniform flows, they are unsuitable for inclined dune co-sets and other cases where multiple scales of bedforms interact. Spatial and temporal variations in flow and sediment transport betweenthe thalweg and different positions on larger bar-forms can change the preservation potential of dunes within river channels. Therefore, dune set thickness distributions are likely grouped in larger-scale units that reflect both formative dune geometries and bar-scale variations inpreservation potential. The multi-scale dynamics of preservation highlighted herein also provides a useful comparison for other sedimentary systemsFil: Reesink, Arnold J.. University Of Binghamton; Estados UnidosFil: Van den Berg, J. H.. University of Utrecht; Países BajosFil: Parsons, Daniel R.. University Of Hull; Reino UnidoFil: Amsler, Mario Luis. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Best, James L.. University of Illinois. Urbana - Champaign; Estados UnidosFil: Hardy, Richard J.. University Of Durham; Reino UnidoFil: Orfeo, Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Szupiany, Ricardo Nicolas. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas; Argentin
Geology of the Kankakee River system in Kankakee County, Illinois
The Kankakee River flows westward from Indiana to Illinois. The headwaters are near South Bend, Indiana, and the mouth is the con- fluence with the Des Plaines River where those two rivers become the Illinois River. In work beginning in the late nineteenth century and essentially completed by 19183 almost all of the main channel of the Kankakee River in Indiana was channelized. Today that channel is a manmade ditch, extending straight for many miles between small bends. In Indiana, all of the natural meanders were removed. In Illinois, a very small dam exists at Momence and a larger dam exists at Kankakee, but most of the river remains a naturally meandering stream. The geologic framework of the Kankakee River as we know it today was established at the time of the melting of the last continental glaciers. That melting occurred during the approximate interval from 16,000 to 13,000 years ago, the latter portion of the Woodfordian Substage of the Wisconsinan Stage. From the time of the glacial melting to the present day, the Kankakee River has carried great quantities of sand westward. Most of the landscape adjacent to the main stem of the Kankakee River in Indiana is sand. The geology of the Illinois portion of the basin is more complex; in Kankakee County, Illinois , it includes silty and clayey glacial tills, silty and clayey lacustrine sediment, exposed bedrock, and sand. From the Illinois-Indiana state line downstream to near the city of Momence, the river channel is underlain by thick deposits of sand overlying bedrock. In the several miles of river channel adjacent to Momence and a 2-mile reach upstream of Aroma Park, the Kankakee River is flowing over bedrock. In the area between the cities of Momence and Aroma Park, the channel contains a series of massive sand bars, up to 1 or 2 meters thick, overlying bedrock. The upper (eastern) end of Six Mile Pool contains thick sand deposits. In the lower end (western) of Six Mile Pool, near the city of Kankakee, the main channel is underlain by bedrock although the insides of the meanders have sand bars. This report was submitted by the Illinois State Geological Survey in fulfillment of Contract 20.121 between the Illinois Institute of Natural Resources and the University of Illinois. It is one of a series of studies of the hydrology and sediment transport (Illinois State Water Survey) , the biology (Illinois Natural History Survey), and the geology (this report) of the Kankakee River system in Illinois
SU(2) Flux Distributions on Finite Lattices
We studied SU(2) flux distributions on four dimensional euclidean lattices
with one dimension very large. By choosing the time direction appropriately we
can study physics in two cases: one is finite volume in the zero temperature
limit, another is finite temperature in the the intermediate to large volume
limit. We found that for cases of beta > beta crit there is no intrinsic string
formation. Our lattices with beta > beta crit belong to intermediate volume
region, and the string tension in this region is due to finite volume effects.
In large volumes we found evidence for intrinsic string formation.Comment: 21 pages text, 12 pages of postscript figure
Comparison of Outcomes Following a Switch from a Brand to an Authorized vs. Independent Generic Drug
Authorized generics are identical in formulation to brand drugs, manufactured by the brand company but marketed as a generic. Generics, marketed by generic manufacturers, are required to demonstrate pharmaceutical and bioequivalence to the brand drug, but repetition of clinical trials is not required. This retrospective cohort study compared outcomes for generics and authorized generics, which serves as a generic vs. brand proxy that minimizes bias against generics. For the seven drugs studied between 1999-2014, 5,234 unique patients were on brand drug prior to generic entry and 4,900 (93.6%) switched to a generic. During the 12-months following the brand-to-generic switch, patients using generics vs. authorized generics were similar in terms of outpatient visits, urgent care visits, hospitalizations, and medication discontinuation. The likelihood of emergency department visits was slightly higher for authorized generics compared with generics. These data suggest that generics were clinically no worse than their proxy brand comparator
Nicotine effects in adolescence and adulthood on cognition and α₄β₂-nicotinic receptors in the neonatal ventral hippocampal lesion rat model of schizophrenia
Rational
Nicotine use in schizophrenia has traditionally been explained as ‘self-medication’ of cognitive and/or nicotinic acetylcholinergic receptor (nAChR) abnormalities.
Objectives
We test this hypothesis in a neurodevelopmental rat model of schizophrenia that shows increased addiction behaviors including enhanced nicotine reinforcement and drug-seeking.
Methods
Nicotine transdermal patch (5 mg/kg/day vs. placebo × 10 days in adolescence or adulthood) effects on subsequent radial-arm maze learning (15 sessions) and frontal-cortical-striatal nAChR densities (α4β2; [3H]-epibatidine binding) were examined in neonatal ventral hippocampal lesion (NVHL) and SHAM-operated rats.
Results
NVHL cognitive deficits were not differentially affected by nicotine history compared to SHAMs. Nicotine history produced minimal cognitive effects while increasing food–reward consumption on the maze, compounding with NVHL-induced overconsumption. Acute nicotine (0.5 mg/kg) delivered before the final maze sessions produced modest improvements in maze performance in rats with nicotine patch histories only, but not differentially so in NVHLs. Consistent with in vivo neuroimaging of β2 nAChR binding in schizophrenia smokers vs. non-smokers and healthy controls, adult NVHLs showed 12% reductions in nAChR binding in MPFC (p.40), whereas nicotine history elevated nAChRs across both regions (>30%, p<0.001) without interacting with NVHLs. Adolescent vs. adult nicotine exposure did not alter nAChRs differentially.
Conclusions
Although replicating nicotine-induced up-regulation of nAChRs in human smokers and demonstrating NVHL validity in terms of schizophrenia-associated nAChR density patterns, these findings do not support hypotheses explaining increased nicotine use in schizophrenia as reflecting illness-specific effects of nicotine to therapeutically alter cognition or nAChR densities
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