942 research outputs found
Cassini atmospheric chemistry mapper. Volume 1. Investigation and technical plan
The Cassini Atmospheric Chemistry Mapper (ACM) enables a broad range of atmospheric science investigations for Saturn and Titan by providing high spectral and spatial resolution mapping and occultation capabilities at 3 and 5 microns. ACM can directly address the major atmospheric science objectives for Saturn and for Titan, as defined by the Announcement of Opportunity, with pivotal diagnostic measurements not accessible to any other proposed Cassini instrument. ACM determines mixing ratios for atmospheric molecules from spectral line profiles for an important and extensive volume of the atmosphere of Saturn (and Jupiter). Spatial and vertical profiles of disequilibrium species abundances define Saturn's deep atmosphere, its chemistry, and its vertical transport phenomena. ACM spectral maps provide a unique means to interpret atmospheric conditions in the deep (approximately 1000 bar) atmosphere of Saturn. Deep chemistry and vertical transport is inferred from the vertical and horizontal distribution of a series of disequilibrium species. Solar occultations provide a method to bridge the altitude range in Saturn's (and Titan's) atmosphere that is not accessible to radio science, thermal infrared, and UV spectroscopy with temperature measurements to plus or minus 2K from the analysis of molecular line ratios and to attain an high sensitivity for low-abundance chemical species in the very large column densities that may be achieved during occultations for Saturn. For Titan, ACM solar occultations yield very well resolved (1/6 scale height) vertical mixing ratios column abundances for atmospheric molecular constituents. Occultations also provide for detecting abundant species very high in the upper atmosphere, while at greater depths, detecting the isotopes of C and O, constraining the production mechanisms, and/or sources for the above species. ACM measures the vertical and horizontal distribution of aerosols via their opacity at 3 microns and, particularly, at 5 microns. ACM recovers spatially-resolved atmospheric temperatures in Titan's troposphere via 3- and 5-microns spectral transitions. Together, the mixing ratio profiles and the aerosol distributions are utilized to investigate the photochemistry of the stratosphere and consequent formation processes for aerosols. Finally, ring opacities, observed during solar occultations and in reflected sunlight, provide a measurement of the particle size and distribution of ring material. ACM will be the first high spectral resolution mapping spectrometer on an outer planet mission for atmospheric studies while retaining a high resolution spatial mapping capability. ACM, thus, opens an entirely new range of orbital scientific studies of the origin, physio-chemical evolution and structure of the Saturn and Titan atmospheres. ACM provides high angular resolution spectral maps, viewing nadir and near-limb thermal radiation and reflected sunlight; sounds planetary limbs, spatially resolving vertical profiles to several atmospheric scale heights; and measures solar occultations, mapping both atmospheres and rings. ACM's high spectral and spatial resolution mapping capability is achieved with a simplified Fourier Transform spectrometer with a no-moving parts, physically compact design. ACM's simplicity guarantees an inherent stability essential for reliable performance throughout the lengthy Cassini Orbiter mission
Multidimensional unfolding: Determining configuration from complete rank order preference data
Within the model of isotonic space, a principle is presented which generalizes the unfolding technique to the multidimensional case. The availability of exhaustive configurational solutions given complete data is pointed out. Finally three criteria are suggested for the choice of a particular solution from among the set of all solutions, which are applicable in the case either of complete or incomplete data.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45710/1/11336_2005_Article_BF02289716.pd
QTL Mapping of a High Protein Digestibility Trait in Sorghum bicolor
Compared with other cereal grains, Sorghum bicolor shows lower protein digestibility. The low digestibility is thought to result from disulfide cross linking in the β- and γ-kafirins. In contrast, the single recessive high digestibility/high lysine content (HD)
mutation which confers greater grain digestibility exists in sorghum that is thought to
result from reduced accumulation of γ-kafirin that allows greater access to the high digestible α-kafarin fraction. In an effort to both clearly define the molecular basis for
the HD trait and develop tools to improve the introgression of this difficult-to-screen trait,
this study focuses on mapping the QTLs linked to this trait. While the HD trait has been
defined as a single recessive gene, our results uncovered that two major QTLs on
chromosome 1 are associated with protein digestibility—one QTL (locus 1 from the HD
parent) unfavorably affects digestibility and one QTL (locus 2 from the HD parent) only
20 cM away favorably affects digestibility. A contrast analysis between genotypic
groups at these two loci shows that a higher level of protein digestibility may be
obtained when this linkage in repulsion is broken and favorable alleles are allowed to
recombine
Future Directions of Evidence-Based Practice in Athletic Training: Perceived Strategies to Enhance the Use of Evidence-Based Practice
Context: The shift to a culture of evidence-based practice (EBP) in athletic training is a necessary step in both the optimization of patient care and the advancement of athletic trainers (ATs) as health care professionals. Whereas individuals have gained knowledge in this area, most ATs still are not practicing in an evidence-based manner. Exploring perceived strategies to enhance the use of EBP will help to determine the best approaches to assist ATs in applying EBP concepts to practice to improve patient care. Objective: To explore beneficial strategies and techniques ATs perceived would promote successful implementation of EBP within athletic training education and clinical practice. Design: Qualitative study. Setting: Individual telephone interviews. Patients or Other Participants:Twenty-five ATs (12 educators, 13 clinicians; athletic training experience = 16.00 ± 9.41 years) were interviewed. Data Collection and Analysis: One phone interview was conducted with each participant. After the interview was transcribed, the data were analyzed and coded into common themes and categories. Triangulation of the data occurred via the use of multiple researchers and member checking to confirm the accuracy of the data. Results: Participants identified several components they perceived as essential for enhancing the use of EBP within the athletic training profession. These components included the need for more EBP resources, more processed information, focused workshops, peer discussion and mentorship, and continual repetition and exposure. Participants also indicated that ATs need to accept their professional responsibilities to foster EBP in their daily practices. Conclusions: The proper shift to a culture of EBP in athletic training will take both time and a persistent commitment by ATs to create strategies that will enhance the implementation of EBP across the profession. Researchers should focus on continuing to identify effective educational interventions for ATs and to determine successful strategies to implement EBP into didactic curricula and clinical practice. Additional focus should be given to which strategies most effectively produce changes in clinical practice
Perceived Outcomes of Web-Based Modules Designed to Enhance Athletic Trainers\u27 Knowledge of Evidence-Based Practice
Context: The release of evidence-based practice (EBP) Web-based learning modules to the membership of the National Athletic Trainers\u27 Association has provided athletic trainers (ATs) the opportunity to enhance their knowledge of the various EBP concepts. Whereas increasing the knowledge of EBP among ATs is important, assessing whether this newfound knowledge is being translated into clinical practice and didactic education is crucial. Objective: To explore the effectiveness of an educational intervention regarding EBP on the didactic instruction patterns of athletic training educators and the clinical practice behaviors of clinicians. Design: Qualitative study. Setting: Individual telephone interviews. Patients or Other Participants: A total of 25 ATs (12 educators, 13 clinicians; experience as an AT = 16.00 ± 9.41 years) were interviewed. Data Collection and Analysis: We conducted 1 individual telephone interview with each participant. After transcription, the data were analyzed and coded into common themes and categories. Triangulation of the data occurred via the use of multiple researchers and member checking to confirm the accuracy of the data. Results: Participants perceived the EBP Web-based modules to produce numerous outcomes regarding education and clinical practice. These outcomes included perceived knowledge gain among participants, an increase in the importance and scope of EBP, a positive effect on educators\u27 didactic instruction patterns and on instilling value and practice of EBP among students, and an enhanced ability among clinicians to implement EBP within clinical practice. However, some clinicians reported the Web-based modules had no current effect on clinical practice. Conclusions: Although the EBP Web-based modules were successful at enhancing knowledge among ATs, translation of knowledge into the classroom and clinical practice remains limited. Researchers should aim to identify effective strategies to help ATs implement EBP concepts into didactic education and clinical practice
Motility Screen Identifies Drosophila IGF-II mRNA-Binding Protein—Zipcode-Binding Protein Acting in Oogenesis and Synaptogenesis
The localization of specific mRNAs can establish local protein gradients that generate and control the development of cellular asymmetries. While all evidence underscores the importance of the cytoskeleton in the transport and localization of RNAs, we have limited knowledge of how these events are regulated. Using a visual screen for motile proteins in a collection of GFP protein trap lines, we identified the Drosophila IGF-II mRNA-binding protein (Imp), an ortholog of Xenopus Vg1 RNA binding protein and chicken zipcode-binding protein. In Drosophila, Imp is part of a large, RNase-sensitive complex that is enriched in two polarized cell types, the developing oocyte and the neuron. Using time-lapse confocal microscopy, we establish that both dynein and kinesin contribute to the transport of GFP-Imp particles, and that regulation of transport in egg chambers appears to differ from that in neurons. In Drosophila, loss-of-function Imp mutations are zygotic lethal, and mutants die late as pharate adults. Imp has a function in Drosophila oogenesis that is not essential, as well as functions that are essential during embryogenesis and later development. Germline clones of Imp mutations do not block maternal mRNA localization or oocyte development, but overexpression of a specific Imp isoform disrupts dorsal/ventral polarity. We report here that loss-of-function Imp mutations, as well as Imp overexpression, can alter synaptic terminal growth. Our data show that Imp is transported to the neuromuscular junction, where it may modulate the translation of mRNA targets. In oocytes, where Imp function is not essential, we implicate a specific Imp domain in the establishment of dorsoventral polarity
Influence of Pregabalin Maintenance on Cannabis Effects and Related Behaviors in Daily Cannabis Users
No medications are approved for cannabis use disorder (CUD), though a small clinical trial demonstrated that the voltage-dependent calcium channel (VDCC) ligand gabapentin reduced cannabis use in treatment seekers. VDCCs are modulated by cannabinoid (CB) ligands, and there are shared effects between CB agonists and VDCC ligands. This overlapping neuropharmacology and the initial clinical results supported the evaluation of pregabalin, a next-generation VDCC ligand, as a CUD medication. Two separate placebo-controlled, double-blind, counterbalanced, within-subjects human laboratory studies tested placebo and 300 (N = 2 females, 11 males; Experiment [EXP] 1) or 450 (N = 3 females, 11 males; EXP 2) mg/day pregabalin in cannabis users who were not seeking treatment or trying to reduce/quit their cannabis use. The protocol consisted of two outpatient maintenance phases (11 days in EXP 1 and 15 days in EXP 2) that concluded with four experimental sessions within each phase. During experimental sessions, maintenance continued, and participants completed two 2-day blocks of sampling and self-administration sessions to determine the reinforcing effects of smoked cannabis (0% and 5.9% delta⁹-tetrahydrocannabinol [THC]), as well as subjective, attentional bias, performance, and physiological responses. In addition, naturalistic cannabis use, side effects, sleep quality, craving, and other self-reported substance use were measured during pregabalin maintenance. Cannabis was self-administered and produced prototypical effects, but pregabalin generally did not impact the effects of cannabis or alter naturalistic use. These human laboratory results in cannabis users not trying to reduce/quit their use do not support the efficacy of pregabalin as a stand-alone pharmacotherapy for CUD
N-Acetylcysteine Reduces Cocaine-Cue Attentional Bias and Differentially Alters Cocaine Self-Administration Based on Dosing Order
Background—Disrupted glutamate homeostasis is thought to contribute to cocaine-use disorder, in particular, by enhancing the incentive salience of cocaine stimuli. n-Acetylcysteine might be useful in cocaine-use disorder by normalizing glutamate function. In prior studies, n-acetylcysteine blocked the reinstatement of cocaine seeking in laboratory animals and reduced the salience of cocaine stimuli and delayed relapse in humans.
Methods—The present study determined the ability of maintenance on n-acetylcysteine (0 or 2400 mg/day, counterbalanced) to reduce the incentive salience of cocaine stimuli, as measured by an attentional bias task, and attenuate intranasal cocaine self-administration (0, 30, and 60 mg). Fourteen individuals (N = 14) who met criteria for cocaine abuse or dependence completed this within-subjects, double-blind, crossover-design study.
Results—Cocaine-cue attentional bias was greatest following administration of 0 mg cocaine during placebo maintenance, and was attenuated by n-acetylcysteine. Cocaine maintained responding during placebo and n-acetylcysteine maintenance, but the reinforcing effects of cocaine were significantly attenuated across both maintenance conditions in participants maintained on n-acetylcysteine first compared to participants maintained on placebo first.
Conclusions—These results collectively suggest that a reduction in the incentive salience of cocaine-related stimuli during n-acetylcysteine maintenance may be accompanied by reductions in cocaine self-administration. These results are in agreement with, and link, prior preclinical and clinical trial results suggesting that n-acetylcysteine might be useful for preventing cocaine relapse by attenuating the incentive salience of cocaine cues
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