6,342 research outputs found

    Early diffusion evidence of retrograde transsynaptic degeneration in the human visual system

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    We investigated whether diffusion tensor imaging (DTI) indices of white matter integrity would offer early markers of retrograde transsynaptic degeneration (RTD) in the visual system after stroke Objective: We investigated whether diffusion tensor imaging (DTI) indices of white matter integrity would offer early markers of retrograde transsynaptic degeneration (RTD) in the visual system after stroke. Methods: We performed a prospective longitudinal analysis of the sensitivity of DTI markers of optic tract health in 12 patients with postsynaptic visual pathway stroke, 12 stroke controls, and 28 healthy controls. We examined group differences in (1) optic tract fractional anisotropy (FA-asymmetry), (2) perimetric measures of visual impairment, and (3) the relationship between FA-asymmetry and perimetric assessment. Results: FA-asymmetry was higher in patients with visual pathway lesions than in control groups. These differences were evident 3 months from the time of injury and did not change significantly at 12 months. Perimetric measures showed evidence of impairment in participants with visual pathway stroke but not in control groups. A significant association was observed between FA-asymmetry and perimetric measures at 3 months, which persisted at 12 months. Conclusions: DTI markers of RTD are apparent 3 months from the time of injury. This represents the earliest noninvasive evidence of RTD in any species. Furthermore, these measures associate with measures of visual impairment. DTI measures offer a reproducible, noninvasive, and sensitive method of investigating RTD and its role in visual impairment

    Combined uncertainty factor for sampling and analysis

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    Measurement uncertainty that arises from primary sampling can be expressed as an uncertainty factor, which recognises its sometimes approximately log-normal probability distribution. By contrast, uncertainty arising from chemical analysis is usually expressed as relative uncertainty, based upon the assumptions of its approximately normal distribution. A new method is proposed that enables uncertainty from these two sources, expressed in these different ways, to be combined to produce an estimate of the total combined uncertainty of the measurement values that result when the measurement process is considered as a whole

    Environmental, developmental, and genetic factors controlling root system architecture

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    A better understanding of the development and architecture of roots is essential to develop strategies to increase crop yield and optimize agricultural land use. Roots control nutrient and water uptake, provide anchoring and mechanical support and can serve as important storage organs. Root growth and development is under tight genetic control and modulated by developmental cues including plant hormones and the environment. This review focuses on root architecture and its diversity and the role of environment, nutrient, and water as well as plant hormones and their interactions in shaping root architecture

    Schiff Theorem and the Electric Dipole Moments of Hydrogen-Like Atoms

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    The Schiff theorem is revisited in this work and the residual PP- and TT-odd electron--nucleus interaction, after the shielding takes effect, is completely specified. An application is made to the electric dipole moments of hydrogen-like atoms, whose qualitative features and systematics have important implication for realistic paramagnetic atoms.Comment: 3 pages. Contribution to PANIC05, Particles and Nuclei International Conference, Santa Fe, New Mexico, Oct. 24-28, 200

    Antibiotic Spacers in Shoulder Arthroplasty: Comparison of Stemmed and Stemless Implants.

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    Background: Antibiotic spacers in shoulder periprosthetic joint infection deliver antibiotics locally and provide temporary stability. The purpose of this study was to evaluate differences between stemmed and stemless spacers. Methods: All spacers placed from 2011 to 2013 were identified. Stemless spacers were made by creating a spherical ball of cement placed in the joint space. Stemmed spacers had some portion in the humeral canal. Operative time, complications, reimplantation, reinfection, and range of motion were analyzed. Results: There were 37 spacers placed: 22 were stemless and 15 were stemmed. The stemless spacer population was older (70.9 ± 7.8 years vs. 62.8 ± 8.4 years, p = 0.006). The groups had a similar percentage of each gender (stemless group, 45% male vs. stemmed group, 40% male; p = 0.742), body mass index (stemless group, 29.1 ± 6.4 kg/m2 vs. stemmed group, 31.5 ± 8.3 kg/m2; p = 0.354) and Charlson Comorbidity Index (stemless group, 4.2 ± 1.2 vs. stemmed group, 4.2 ± 1.7; p = 0.958). Operative time was similar (stemless group, 127.5 ± 37.1 minutes vs. stemmed group, 130.5 ± 39.4 minutes). Two stemless group patients had self-resolving radial nerve palsies. Within the stemless group, 15 of 22 (68.2%) underwent reimplantation with 14 of 15 having forward elevation of 109° ± 23°. Within the stemmed group, 12 of 15 (80.0%, p = 0.427) underwent reimplantation with 8 of 12 having forward elevation of 94° ± 43° (range, 30° to 150°; p = 0.300). Two stemmed group patients had axillary nerve palsies, one of which self-resolved but the other did not. One patient sustained dislocation of reverse shoulder arthroplasty after reimplantation. One stemless group patient required an open reduction and glenosphere exchange of dislocated reverse shoulder arthroplasty at 6 weeks after reimplantation. Conclusions: Stemmed and stemless spacers had similar clinical outcomes. When analyzing all antibiotic spacers, over 70% were converted to revision arthroplasties. The results of this study do not suggest superiority of either stemmed or stemless antibiotic spacers

    Wide-angle elastic scattering and color randomization

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    Baryon-baryon elastic scattering is considered in the independent scattering (Landshoff) mechanism. It is suggested that for scattering at moderate energies, direct and interchange quark channels contribute with equal color coefficients because the quark color is randomized by soft gluon exchange during the hadronization stage. With this assumption, it is shown that the ratio of cross sections Rp‾p/ppR_{\overline{p} p/ p p} at CM angle θ=900\theta = 90^0 decreases from a high energy value of R_{\pbar p / pp} \approx 1/2.7, down to R_{\pbar p / pp} \approx 1/28, compatible with experimental data at moderate energies. This sizable fall in the ratio seems to be characteristic of the Landshoff mechanism, in which changes at the quark level have a strong effect precisely because the hadronic process occurs via multiple quark scatterings. The effect of color randomization on the angular distribution of proton-proton elastic scattering and the cross section ratio Rnp/ppR_{np/pp} is also discussed.Comment: 18 pages, latex2e, 4 uuencoded figures, include

    Outcomes of Shoulder Arthroplasty Performed for Postinfectious Arthritis.

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    Background: The purpose of this study was to evaluate the functional outcomes, infection rate, and complications associated with shoulder arthroplasty for sequelae of prior septic arthritis. Methods: This is a retrospective cohort study of 17 patients who underwent shoulder arthroplasty for sequelae of septic arthritis. Patients were analyzed for patient-reported outcomes, complications, and reoperations. Results: The 17 patients in this cohort were an average age of 65.4 ± 12.2 years old, were 58.8% male, and had an average body mass index of 27.9 ± 4.1 kg/m Conclusions: Shoulder arthroplasty after septic arthritis had inconsistent functional outcomes and high complication rates but no reinfection

    Self- and Partner-objectification in Romantic Relationships: Associations with Media Consumption and Relationship Satisfaction

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    Few studies have examined objectification in the context of romantic relationships, even though strong theoretical arguments have often made this connection. This study addresses this gap in the literature by examining whether exposure to mass media is related to self-objectification and objectification of one’s partner, which in turn is hypothesized to be related to relationship and sexual satisfaction. A sample of undergraduate students (91 women and 68 men) enrolled in a university on the west coast of the United States completed self-report measures of the following variables: self-objectification, objectification of one’s romantic partner, relationship satisfaction, sexual satisfaction, and exposure to objectifying media. Men reported higher levels of partner objectification than did women; there was no gender difference in self-objectification. Self- and partner-objectification were positively correlated; this correlation was especially strong for men. In regression analyses, partner-objectification was predictive of lower levels of relationship satisfaction. Furthermore, a path model revealed that consuming objectifying media is related to lowered relationship satisfaction through the variable of partner-objectification. Finally, self- and partner-objectification were related to lower levels of sexual satisfaction among men. This study provides evidence for the negative effects of objectification in the context of romantic relationships among young adults

    Biodegradable Shooting Targets Acidify Soils, Limit Plant Growth, and Mobilize Lead

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    Environmental waste from recreational shotgun shooting includes lead pellet and target debris. The main risk of lead pellets is that they can be ingested by birds as they swallow pebbles and grit that aid in digestion. Another possible vector of toxicity is when acidic soil conditions mobilize lead ions from the solid pellets into the soil and groundwater. Historically, secondary waste resulted from petroleum pitch based targets that persisted in the environment for years. To reduce the environmental lifetime of targets, biodegradable targets were developed. At a former sporting clay shooting range in Florence, Montana, we found that as biodegradable targets degraded, their sulfuric components oxidized to release acid; as a result, soil pH was as low as 2. Target abundance correlated with decreased soil pH (?=-0.681, P<0.001) and decreased plant cover (p=-0.770, P<0.001). These acidic soils increased the mobility of lead from shot pellets and now lead concentrations exceed background. Our results demonstrate that biodegradable shooting targets exacerbate the environmental hazards that result from lead shotfall. Careful considerations regarding target composition and shooting locations may minimize environmental exposure to toxicants
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