5,229 research outputs found
Airborne sulfur trace species intercomparison campaign: Sulfur dioxide, dimethylsulfide, hydrogen sulfide, carbon disulfide, and carbonyl sulfide
Results from an airborne intercomparison of techniques to measure tropospheric levels of sulfur trace gases are presented. The intercomparison was part of the NASA Global Tropospheric Experiment (GTE) and was conducted during the summer of 1989. The intercomparisons were conducted on the Wallops Electra aircraft during flights from Wallops Island, Virginia, and Natal, Brazil. Sulfur measurements intercompared included sulfur dioxide (SO2), dimethylsulfide (DMS), hydrogen sulfide (H2S), carbon disulfide (CS2), and carbonyl sulfide (OCS). Measurement techniques ranged from filter collection systems with post-flight analyses to mass spectrometer and gas chromatograph systems employing various methods for measuring and identifying the sulfur gases during flight. Sampling schedules for the techniques ranged from integrated collections over periods as long as 50 minutes to one- to three-minute samples every ten or fifteen minutes. Several of the techniques provided measurements of more than one sulfur gas. Instruments employing different detection principles were involved in each of the sulfur intercomparisons. Also included in the intercomparison measurement scenario were a host of supporting measurements (i.e., ozone, nitrogen oxides, carbon monoxide, total sulfur, aerosols, etc.) for purposes of: (1) interpreting results (i.e., correlation of any noted instrument disagreement with the chemical composition of the measurement environment); and (2) providing supporting chemical data to meet CITE-3 science objectives of studying ozone/sulfur photochemistry, diurnal cycles, etc. The results of the intercomparison study are briefly discussed
The Dilaton and Modified Gravity
We consider the dilaton in the strong string coupling limit and elaborate on
the original idea of Damour and Polyakov whereby the dilaton coupling to matter
has a minimum with a vanishing value at finite field-value. Combining this type
of coupling with an exponential potential, the effective potential of the
dilaton becomes matter density dependent. We study the background cosmology,
showing that the dilaton can play the role of dark energy. We also analyse the
constraints imposed by the absence of violation of the equivalence principle.
Imposing these constraints and assuming that the dilaton plays the role of dark
energy, we consider the consequences of the dilaton on large scale structures
and in particular the behaviour of the slip functions and the growth index at
low redshift.Comment: 14 pages, 4 figure
The connective Morava K-theory of the second mod p Eilenberg-MacLane space
We develop tools for computing the connective n-th Morava K-theory of spaces.
Starting with a Universal Coefficient Theorem that computes the cohomology
version from the homology version, we show that every step in the process of
computing one is mirrored in the other and that this can be used to make
computations. As our example, we compute the connective n-th Morava K-theory of
the second mod p Eilenberg-MacLane space.Comment: minor change of title and one sentence adde
Twist and Measure: Characterizing the Effective Radius of Strings and Bundles under Twisting Contraction
We test the standard model for the length contraction of a bundle of strings
under twist, and find deviation that is significantly greater than typically
appreciated and that has a different nature at medium and large twist angles.
By including volume conservation, we achieve better fits to data for single-,
double-, and triple-stranded bundles of Nylon monofilament as an ideal test
case. This gives a well-defined procedure for extracting an effective twist
radius that characterizes contraction behavior. While our approach accounts for
the observed faster-than-expected contraction up to medium twist angles, we
also find that the contraction is nevertheless slower than expected at large
twist angles for both Nylon monofilament bundles and several other string
types. The size of this effect varies with the individual-string braid
structure and with the number of strings in the bundle. We speculate that it
may be related to elastic deformation within the material. However, our first
modeling attempt does not fully capture the observed behavior.Comment: 8 pages, 8 figure
One Loop Predictions of the Finely Tuned SSM
We study the finely tuned SSM, recently proposed by Arkani-Hamed and
Dimopoulos, at the one loop level. The runnings of the four gaugino Yukawa
couplings, the mu term, the gaugino masses, and the Higgs quartic coupling are
computed. The Higgs mass is found to be 130 - 170 GeV for M_s > 10^6 GeV. If
the Yukawa coupling constants are measured at the 1% level, this can determine
the SUSY breaking scale to within an order of magnitude. Measuring the
relationships between the couplings to this accuracy provides a striking signal
for this model.Comment: 5 pages, 4 figures; v2: Minor corrections to anomalous dimensions and
beta functions. Numerical results are not significantly affected. v3: Minor
changes to figures and references, as published in PR
The Value of Information Technology-Enabled Diabetes Management
Reviews different technologies used in diabetes disease management, as well as the costs, benefits, and quality implications of technology-enabled diabetes management programs in the United States
Response rates for mailout survey-driven studies in patients with head and neck cancer
Background: Mailout survey studies are becoming more prevalent in the head and neck literature. The objective of this paper is to summarize response rates in patients with head and neck cancer, and to provide recommendations surrounding methodology used to design and implement mailout survey questionnaires. Methods: The results of this paper are from a study assessing the measurement properties of the Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH) in head and neck cancer patients. A modified Dillman tailored design approach was used. Results: The methods used yielded a response rate of 80% with this patient population. Conclusion: This is a considerably higher response rate than other reports in the oncology literature. © 2010 Wiley Periodicals, Inc. Head Neck, 2010Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78489/1/21363_ftp.pd
Bayesian Spatiotemporal Pattern and Eco-climatological Drivers of Striped Skunk Rabies in the North Central Plains
Citation: Raghavan, R. K., Hanlon, C. A., Goodin, D. G., Davis, R., Moore, M., Moore, S., & Anderson, G. A. (2016). Bayesian Spatiotemporal Pattern and Eco-climatological Drivers of Striped Skunk Rabies in the North Central Plains. Plos Neglected Tropical Diseases, 10(4), 16. doi:10.1371/journal.pntd.0004632Striped skunks are one of the most important terrestrial reservoirs of rabies virus in North America, and yet the prevalence of rabies among this host is only passively monitored and the disease among this host remains largely unmanaged. Oral vaccination campaigns have not efficiently targeted striped skunks, while periodic spillovers of striped skunk variant viruses to other animals, including some domestic animals, are routinely recorded. In this study we evaluated the spatial and spatio-temporal patterns of infection status among striped skunk cases submitted for rabies testing in the North Central Plains of US in a Bayesian hierarchical framework, and also evaluated potential eco-climatological drivers of such patterns. Two Bayesian hierarchical models were fitted to point-referenced striped skunk rabies cases [n = 656 (negative), and n = 310 (positive)] received at a leading rabies diagnostic facility between the years 2007-2013. The first model included only spatial and temporal terms and a second covariate model included additional covariates representing eco-climatic conditions within a 4km(2) home-range area for striped skunks. The better performing covariate model indicated the presence of significant spatial and temporal trends in the dataset and identified higher amounts of land covered by low-intensity developed areas [Odds ratio (OR) = 3.41; 95% Bayesian Credible Intervals (CrI) = 2.08, 3.85], higher level of patch fragmentation (OR = 1.70; 95% CrI = 1.25, 2.89), and diurnal temperature range (OR = 0.54; 95% CrI = 0.27, 0.91) to be important drivers of striped skunk rabies incidence in the study area. Model validation statistics indicated satisfactory performance for both models; however, the covariate model fared better. The findings of this study are important in the context of rabies management among striped skunks in North America, and the relevance of physical and climatological factors as risk factors for skunk to human rabies transmission and the space-time patterns of striped skunk rabies are discussed
Epoxy Composites Using Wood Pulp Components as Fillers
The components of wood, especially lignin and cellulose, have great potential for improving the properties of polymer composites. In this chapter, we discuss some of the latest developments from our lab on incorporating wood-based materials into epoxy composites. Lignosulfonate was used as a flame retardant and cellulose nanocrystals were used as reinforcing materials. Lignosulfonate will disperse well in epoxy, but phase separates during curing. An epoxidation reaction was developed to immobilize the lignosulfonate during curing. The lignosulfonate–epoxy composites were characterized using microcombustion and cone calorimetry tests. Cellulose also has poor interfacial adhesion to hydrophobic polymer matrices. Cellulose fibers and nanocrystals aggregate when placed in epoxy resin, resulting in very poor dispersion. The cellulose nanocrystal surface was modified with phenyl containing materials to disrupt cellulose interchain hydrogen bonding and improve dispersion in the epoxy resin. The cellulose nanocrystal – epoxy composites were characterized for mechanical strength using tensile tests, water barrier properties using standardized water absorption, glass transition temperatures using differential calorimetry, and aggregation and dispersion using microscopic techniques
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