Low Shrinkage Bleaching of Unbleached Neutral Sulphite Semichemical Pulp

The main objective of this research project was the investigation of the most feasible method for the bleaching of a soft-cooked unbleached neutral sulphite semichemical aspen pulp cooked to a 70 percent yield. Furthermore, treatment of unbleached, laboratory bleached and commercially bleached neutral sulphite semichemical pulp with a new chemical, sodium borohydride, was also carried out. The results of our experimental work showed that, the best bleaching procedure was when 15 percent chlorine as hypochlorite was used in the first stage, followed by a hydrochloric acid soaking stage with a final treatment of 2.6 percent hydrogen peroxide. With the above procedure brightness values over 80 percent were obtained with the yields in the 90 percent range based on the weight of the pulp. Sodium borohydride treatment of the three pulps showed that, with regards to ultra-violet light and heat stability the chemical, sodium borohydride, had no effect on the unbleached and the bleached lignin-containing pulps. Treatment of the commercially bleached, lignin-free, pulp however showed that the chemical had a marked effect in improving the heat and light stability of the pulp. It was noted that with all three types of pulp the chemical sodium borohydride did procedure a bleaching effect

Picosecond timing of Microwave Cherenkov Impulses from High-Energy Particle Showers Using Dielectric-loaded Waveguides

We report on the first measurements of coherent microwave impulses from high-energy particle-induced electromagnetic showers generated via the Askaryan effect in a dielectric-loaded waveguide. Bunches of 12.16 GeV electrons with total bunch energy of $\sim 10^3-10^4$ GeV were pre-showered in tungsten, and then measured with WR-51 rectangular (12.6 mm by 6.3 mm) waveguide elements loaded with solid alumina ($Al_2 O_3$) bars. In the 5-8 GHz $TE_{10}$ single-mode band determined by the presence of the dielectric in the waveguide, we observed band-limited microwave impulses with amplitude proportional to bunch energy. Signals in different waveguide elements measuring the same shower were used to estimate relative time differences with 2.3 picosecond precision. These measurements establish a basis for using arrays of alumina-loaded waveguide elements, with exceptional radiation hardness, as very high precision timing planes for high-energy physics detectors.Comment: 16 pages, 15 figure

Knowledge, Attitudes and Beliefs That May Influence Infant Feeding Practices in American Indian Mothers

The promotion of healthy infant feeding is increasingly recognized as an important obesity prevention strategy. This is relevant for American Indian (AI) populations, who exhibit high levels of obesity and low compliance with infant feeding guidelines. The literature examining the knowledge, attitudes and beliefs (KAB) surrounding infant feeding within the AI population is sparse and focuses primarily on breastfeeding, with limited information on the introduction of solid foods and related practices that may be important in an obesity prevention context. This research presents descriptive findings from a baseline KAB questionnaire on infant feeding and related behaviors, administered to mothers (n=438) from five Northwest AI tribes that participated in the Prevention of Toddler Overweight and Teeth Health Study (PTOTS). Enrollment occurred during pregnancy or up to 6 months postpartum. The KAB questionnaire focused on themes of Breastfeeding/Formula Feeding and Introducing Solid Foods, with supplemental questions on Physical Activity. Knowledge questions were multiple-choice or true/false. Attitudes and beliefs were assessed on Likert scales. Descriptive statistics included frequencies and percents, and means and standard deviations. Most women knew basic breastfeeding recommendations and facts, but fewer recognized the broader health benefits of breastfeeding (e.g., reducing diabetes risk), or knew when to introduce solid foods. Women believed breastfeeding to be healthy and perceived their social networks to agree. Attitudes and beliefs about formula feeding and social support were more ambivalent. This work suggests opportunities to increase the perceived value of breastfeeding to include broader health benefits, increase knowledge about solid foods, and strengthen social support

Listening to Girls and Boys Talk About Girls’ Physical Activity Behaviors

As part of the formative assessment for the Trial of Activity for Adolescent Girls (TAAG), a multicenter study to reduce the decline of physical activity in adolescent girls, girls and boys with diverse ethnicity from six states participated in focus groups and semistructured interviews. Data from 13 girls’ focus groups (N = 100), 11 boys’ focus groups (N = 77), and 80 semistructured interviews with girls are examined to identify perceptions of girls’ physical activity behaviors to help develop TAAG interventions. Both girls and boys talk about physically active girls as being “tomboys” or “too aggressive.” Girls are more likely to characterize active girls as “in shape,” whereas boys say they are “too athletic.” Girls report boys to be influential barriers and motivators in shaping their beliefs about physical activity. Given the strong influence of peers, developing successful interventions for girls should include verbal persuasion, modeling, and social support from both girls and boys

Vertebrate Natural History Notes from Arkansas, 2018

Because meaningful observations of natural history are not always part of larger studies, important pieces of information often are unreported. Small details, however, can fill gaps in understanding and lead to interesting questions about ecological relationships or environmental change. We have compiled recent important observations of distribution, deformities, and foods of various vertebrates, observations of winter activity of a woodchuck (Marmota monax) and winter torpor of a hoary bat (Lasiurus cinereus), and also report a very unusual case of bilateral gynandromorphism in a Cardinal (Cardinalis cardinalis). These unique observations continue to add immensely to the growth of knowledge of the biology of vertebrates in Arkansas

Accelerator measurements of magnetically-induced radio emission from particle cascades with applications to cosmic-ray air showers

For fifty years, cosmic-ray air showers have been detected by their radio emission. We present the first laboratory measurements that validate electrodynamics simulations used in air shower modeling. An experiment at SLAC provides a beam test of radio-frequency (RF) radiation from charged particle cascades in the presence of a magnetic field, a model system of a cosmic-ray air shower. This experiment provides a suite of controlled laboratory measurements to compare to particle-level simulations of RF emission, which are relied upon in ultra-high-energy cosmic-ray air shower detection. We compare simulations to data for intensity, linearity with magnetic field, angular distribution, polarization, and spectral content. In particular, we confirm modern predictions that the magnetically induced emission in a dielectric forms a cone that peaks at the Cherenkov angle and show that the simulations reproduce the data within systematic uncertainties.Comment: 5 pages, 7 figure

Temporal changes in rock uplift rates of folds in the foreland of the Tian Shan and the Pamir from geodetic and geologic data

Understanding the evolution of continental deformation zones relies on quantifying spatial and temporal changes in deformation rates of tectonic structures. Along the eastern boundary of the Pamir‐Tian Shan collision zone, we constrain secular variations of rock uplift rates for a series of five Quaternary detachment‐ and fault‐related folds from their initiation to the modern day. When combined with GPS data, decomposition of interferometric synthetic aperture radar time series constrains the spatial pattern of surface and rock uplift on the folds deforming at decadal rates of 1–5 mm/yr. These data confirm the previously proposed basinward propagation of structures during the Quaternary. By fitting our geodetic rates and previously published geologic uplift rates with piecewise linear functions, we find that gradual rate changes over >100 kyr can explain the interferometric synthetic aperture radar observations where changes in average uplift rates are greater than ~1 mm/yr among different time intervals (~10¹, 10⁴‾⁵, and 10⁵‾⁶ years)

Use of resuscitation promoting factors to screen for tuberculosis infection in household-exposed children in The Gambia.

BACKGROUND: Interferon-γ release assays (IGRA) with Resuscitation promoting factor (Rpf) proteins enhanced tuberculosis (TB) screening and diagnosis in adults but have not been evaluated in children. Children often develop paucibacillary TB and their immune response differs from that of adults, which together affect TB disease diagnostics and immunodiagnostics. We assessed the ability of Rpf to identify infection among household TB-exposed children in The Gambia and investigated their ability to discriminate Mycobacterium tuberculosis complex (MTBC) infection from active TB disease in children. METHODS: Detailed clinical investigations were done on 93 household TB-exposed Gambian children and a tuberculin skin test (TST) was administered to asymptomatic children. Venous blood was collected for overnight stimulation with ESAT-6/CFP-10-fusion protein (EC), purified protein derivative and RpfA, B, C, D and E. Interferon gamma (IFN-γ) production was measured by ELISA in supernatants and corrected for the background level. Infection status was defined by IGRA with EC and TB disease by mycobacterial confirmation and/or clinical diagnosis. We compared IFN-γ levels between infected and uninfected children and between infected and TB diseased children using a binomial logistic regression model while correcting for age and sex. A Receiver Operating Characteristics analysis was done to find the best cut-off for IFN-γ level and calculate sensitivity and specificity. RESULTS: Interferon gamma production was significantly higher in infected (IGRA+, n = 45) than in uninfected (IGRA-, n = 20) children after stimulation with RpfA, B, C, and D (P = 0.03; 0.007; 0.03 and 0.003, respectively). Using RpfB and D-specific IFN-γ cut-offs (33.9 pg/mL and 67.0 pg/mL), infection was classified with a sensitivity-specificity combination of 73-92% and 77-72% respectively, which was similar to and better than 65-75% for TST. Moreover, IFN-γ production was higher in infected than in TB diseased children (n = 28, 5 bacteriologically confirmed, 23 clinically diagnosed), following RpfB and D stimulation (P = 0.02 and 0.03, respectively). CONCLUSION: RpfB and RpfD show promising results for childhood MTBC infection screening, and both performed similar to and better than the TST in our study population. Additionally, both antigens appear to discriminate between infection and disease in children and thus warrant further investigation as screening and diagnostic antigens for childhood TB

Correlates of Physical Activity in Black, Hispanic, and White Middle School Girls

Background: A need exists to better understand multilevel influences on physical activity among diverse samples of girls. This study examined correlates of moderate-to-vigorous physical activity (MVPA) among adolescent girls from different racial/ethnic backgrounds. Methods: 1,180 6th grade girls (24.5% black, 15.7% Hispanic, and 59.8% white) completed a supervised self-administered questionnaire that measured hypothesized correlates of PA. MVPA data were collected for 6 days using the ActiGraph accelerometer. Hierarchical regression analysis was used to examine correlates of PA in each racial/ethnic group. Results: Hispanic girls (n=185) engaged in 21.7 minutes of MVPA per day, black girls (n=289) engaged in 19.5 minutes of MVPA per day, and white girls (n=706) engaged in 22.8 minutes of MVPA per day. Perceived transportation barriers (+; P=.010) were significantly and positively related to MVPA for Hispanic girls. For black girls, Body Mass Index (BMI) (-; P\u3c.005) and social support from friends (+; P=.006) were significant correlates of MVPA. For white girls, BMI (-; P\u3c.001), barriers (-; P=.012), social support from friends (+; P=.010), participation in school sports (+; P=.009), and community sports (+; P=.025) were significant correlates of MVPA. Explained variance ranged from 30% to 35%. Conclusions: Correlates of MVPA varied by racial/ethnic groups. Effective interventions in ethnically diverse populations may require culturally tailored strategies