1,612 research outputs found
Recent Advancements and Remaining Challenges Associated With Inner Magnetosphere CrossâEnergy/Population Interactions (IMCEPI)
The geospace inner magnetosphere, within about 10 Earth radii, contains various plasma populations with energy from a few electron volts to megaelectron volts and plays important roles in regulating the energy density of the magnetosphere, the magnetic field configuration, and wave dynamics. As an integrated part of the magnetosphere, the inner magnetosphere region also ties to other regions and can change the global geospace circulation. Therefore, understanding both internal and external crossâenergy/population interactions can help further our knowledge of the inner magnetosphere dynamics and nonlinear feedback processes. In view of this, in the past 5Â years (2014â2018), the Geospace Environment Modeling (GEM) Focus Group âinner magnetosphere crossâenergy/population interactions (IMCEPI)â has gathered and boosted communityâwide interactions among observation, simulation, and modeling studies. This commentary reports some major accomplishments of the interactive inner magnetosphere community that were advanced by the IMCEPI Focus Group discussions and layouts remaining challenges that need to be carried on.Key PointsAdvancements on firstâprinciple ring current models, new empirical models on IM fields/waves/plasma and application of innovative techniquesAdvanced knowledge of IM characteristics, e.g., compositions, fields, coupling with ionosphere/tail region, and wave particle interactionsChallenges remain in numerical representation of IM and its linkage with other related areas; validation needed across various IM modelsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148385/1/jgra54772_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148385/2/jgra54772.pd
Adapting School-Based Substance Use Prevention Curriculum Through Cultural Grounding: A Review and Exemplar of Adaptation Processes for Rural Schools
A central challenge facing twenty-first century community-based researchers and prevention scientists is curriculum adaptation processes. While early prevention efforts sought to develop effective programs, taking programs to scale implies that they will be adapted, especially as programs are implemented with populations other than those with whom they were developed or tested. The principle of cultural grounding, which argues that health message adaptation should be informed by knowledge of the target population and by cultural insiders, provides a theoretical rational for cultural regrounding and presents an illustrative case of methods used to reground the keepinâ it REAL substance use prevention curriculum for a rural adolescent population. We argue that adaptation processes like those presented should be incorporated into the design and dissemination of prevention interventions
Therapeutic Monoclonal Antibodies to Prevent Tuberculosis Infection
Mycobacteria tuberculosis (Mtb) is a major cause of human morbidity and mortality. Transmission occurs through inhalation of aerosolized Mtb and the initial infection is believed to occur primarily in the alveolar macrophage, although Mtb can infect other cells residing in the lung including dendritic cells, pneumocytes and M cells. Several molecules derived from Mtb are involved in the attachment of the organism to host receptors (opsonic and non-opsonic), which have been reasonably well elucidated. However, a complete understanding of how Mtb attaches to the host and the relative importance of each mechanism on the outcome of infection remains elusive. We hypothesize that protection from infection is possible by blocking the critical initial surface interactions of the organism with the host cell using specific monoclonal antibodies (mAbs). To develop effective mAbs, the outermost layers of Mtb, the capsule and outer membrane, were isolated and characterized by protein gel and LC/MS/MS. Approximately 1000 different proteins were identified in the isolations, of which ~25% were unique to one of the two fractions. The capsule or outer membrane preparations were used as antigens to immunize CD1 mice for up to 12 weeks to generate antibodies via traditional hybridoma generation. Antibodies were screened, selected and characterized by their ability to bind whole cell Mtb by ELISA, demonstration of unique heavy chain variable region sequence and binding specificity by Western Blot. Of approximately 1500 screened hybridomas, 30 lead mAbs have been isolated with specificity to various targets. Preliminary results suggest several of the lead mAb candidates are able to prevent Mtb-induced macrophage cell death in vitro. Future studies will attempt to confirm efficacy in vivo after aerosolized infection in mice with mAb-coated Mtb or parenteral administration of mAb(s). Targets of functional mAbs will be determined and these antigens could serve as viable candidates for vaccine development
Content analysis, cultural grammars, and computers
This paper describes current theoretical work in a cognitive anthropological approach to the analysis of oral literature. A theory of narrative grammar is presented along with the description of a computer program, SAGE, that is currently under development. SAGE facilitates the labelling of clauses and sentences by different types of semantic features. It maps and counts the occurrences of these in the stories analyzed. © 1991 Human Sciences Press, Inc
Screening of Hydrodynamic Interactions in Semidilute Polymer Solutions: A Computer Simulation Study
We study single-chain motion in semidilute solutions of polymers of length N
= 1000 with excluded-volume and hydrodynamic interactions by a novel algorithm.
The crossover length of the transition from Zimm (short lengths and times) to
Rouse dynamics (larger scales) is proportional to the static screening length.
The crossover time is the corresponding Zimm time. Our data indicate Zimm
behavior at large lengths but short times. There is no hydrodynamic screening
until the chains feel constraints, after which they resist the flow:
"Incomplete screening" occurs in the time domain.Comment: 3 figure
Critical behaviour of the Rouse model for gelling polymers
It is shown that the traditionally accepted "Rouse values" for the critical
exponents at the gelation transition do not arise from the Rouse model for
gelling polymers. The true critical behaviour of the Rouse model for gelling
polymers is obtained from spectral properties of the connectivity matrix of the
fractal clusters that are formed by the molecules. The required spectral
properties are related to the return probability of a "blind ant"-random walk
on the critical percolating cluster. The resulting scaling relations express
the critical exponents of the shear-stress-relaxation function, and hence those
of the shear viscosity and of the first normal stress coefficient, in terms of
the spectral dimension of the critical percolating cluster and the
exponents and of the cluster-size distribution.Comment: 9 pages, slightly extended version, to appear in J. Phys.
Scope and Mechanistic Study of the Coupling Reaction of α,ÎČ-Unsaturated Carbonyl Compounds with Alkenes: Uncovering Electronic Effects on Alkene Insertion vs Oxidative Coupling Pathways
The cationic ruthenium-hydride complex [(C6H6)(PCy3)(CO)RuH]+BF4â (1) was found to be a highly effective catalyst for the intermolecular conjugate addition of simple alkenes to α,ÎČ-unsaturated carbonyl compounds to give (Z)-selective tetrasubstituted olefin products. The analogous coupling reaction of cinnamides with electron-deficient olefins led to the oxidative coupling of two olefinic CâH bonds in forming (E)-selective diene products. The intramolecular version of the coupling reaction efficiently produced indene and bicyclic fulvene derivatives. The empirical rate law for the coupling reaction of ethyl cinnamate with propene was determined as follows: rate = k[1]1[propene]0[cinnamate]â1. A negligible deuterium kinetic isotope effect (kH/kD = 1.1 ± 0.1) was measured from both (E)-C6H5CHâC(CH3)CONHCH3 and (E)-C6H5CDâC(CH3)CONHCH3 with styrene. In contrast, a significant normal isotope effect (kH/kD = 1.7 ± 0.1) was observed from the reaction of (E)-C6H5CHâC(CH3)CONHCH3 with styrene and styrene-d8. A pronounced carbon isotope effect was measured from the coupling reaction of (E)-C6H5CHâCHCO2Et with propene (13C(recovered)/13C(virgin) at CÎČ = 1.019(6)), while a negligible carbon isotope effect (13C(recovered)/13C(virgin) at CÎČ = 0.999(4)) was obtained from the reaction of (E)-C6H5CHâC(CH3)CONHCH3 with styrene. Hammett plots from the correlation of para-substituted p-X-C6H4CHâCHCO2Et (X = OCH3, CH3, H, F, Cl, CO2Me, CF3) with propene and from the treatment of (E)-C6H5CHâCHCO2Et with a series of para-substituted styrenes p-Y-C6H4CHâCH2 (Y = OCH3, CH3, H, F, Cl, CF3) gave the positive slopes for both cases (Ï = +1.1 ± 0.1 and +1.5 ± 0.1, respectively). Eyring analysis of the coupling reaction led to the thermodynamic parameters, ÎH⧧ = 20 ± 2 kcal molâ1 and ÎS⧧ = â42 ± 5 eu. Two separate mechanistic pathways for the coupling reaction have been proposed on the basis of these kinetic and spectroscopic studies
Assessment of the dining environment on and near the campuses of fifteen post-secondary institutions
Objective: The present study evaluated the restaurant and dining venues on and near post-secondary campuses varying in institution size. Design: The Nutrition Environment Measures Survey for Restaurants (NEMS-R) was modified to evaluate restaurants as fast food, sit down and fast casual; and campus dining venues as dining halls, student unions and snack bar/cafe Ìs. ANOVA with post hoc Tukeyâs B and T tests were used to distinguish differences between dining venues and associated institutions by size.
Setting: The study was conducted at fifteen US post-secondary institutions, 2009â2011. Subjects: Data presented are from a sample of 175 restaurants and sixty-eight on-campus dining venues.
Results: There were minimal differences in dining halls by institution size, although medium-sized institutions as compared with small-sized institutions offered significantly more healthful side dish/salad bar items. Dining halls scored significantly higher than student unions or snack bar/cafe Ìs on healthful entre Ìes, side dish/salad bar and beverages offerings, but they also had the most barriers to healthful dietary habits (i.e. all-you-can-eat). No differences were found by restaurant type for NEMS-R scores for total restaurant dining environment or healthful entre Ìes and barriers. Snack bars had more healthful side dishes (P 5 0?002) and fast-food restaurants had the highest level of facilitators (i.e. nutrition information; P 5 0?002).
Conclusions: Based on this evaluation in fifteen institutions, the full campus dining environment provides limited support for healthy eating and obesity prevention. The quality of campus dining environments can be improved via healthful offerings, providing nutrition information and other supports to facilitate healthy eating and prevent unwanted weight gain
Self-diffusion in binary blends of cyclic and linear polymers
A lattice model is used to estimate the self-diffusivity of entangled cyclic
and linear polymers in blends of varying compositions. To interpret simulation
results, we suggest a minimal model based on the physical idea that constraints
imposed on a cyclic polymer by infiltrating linear chains have to be released,
before it can diffuse beyond a radius of gyration. Both, the simulation, and
recently reported experimental data on entangled DNA solutions support the
simple model over a wide range of blend compositions, concentrations, and
molecular weights.Comment: 10 pages, 2 figure
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