400 research outputs found

    Mixed sand–mud bedforms produced by transient turbulent flows in the fringe of submarine fans: Indicators of flow transformation

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    The fringe of fine‐grained deep‐marine systems often exhibits complex sedimentary facies and facies associations, because the presence of clay promotes the development of transient turbulent flows with complex depositional properties. Relatively little is known about the variation of current‐induced sedimentary structures found within these facies. This study provides the first comprehensive description and interpretation of mixed sandstone–mudstone bedforms observed in the fringe of the mud‐rich submarine fan that makes up the Aberystwyth Grits Group and Borth Mudstone Formation (Wales, United Kingdom). Using textural and structural descriptions, 158 bedforms in sediment gravity flow deposits were characterized into three main types: ‘classic’ sandy current ripples, large current ripples and low‐amplitude bed‐waves. The sandy current ripples comprise clean sandstone, with average heights and lengths of 11 mm and 141 mm, respectively. The large current ripples are composed of mixed sandstone–mudstone and possess greater dimensions than the sandy current ripples, with an average height of 19 mm and an average length of 274 mm. The low‐amplitude bed‐waves are long thin bedforms composed commonly of mixed sandstone–mudstone, with an average height and length of 10 mm and 354 mm, respectively. The large current ripples and low‐amplitude bed‐waves are strikingly similar to experimental bedforms produced under decelerating mixed sand–mud flows and are interpreted to form beneath transitional flows with enhanced and attenuated near‐bed turbulence, respectively. From the fringe to the distal fringe of the fan, the dominant bedform type changed from sandy current ripples, via large current ripples, to low‐amplitude bed‐waves, suggesting that the flows changed from turbulent to increasingly turbulence‐modulated. It is proposed that the flow Reynolds number reduced, reflecting this flow transformation, from a combination of constant or decreasing flow height, flow deceleration from sediment deposition, and increasing flow viscosity due to the shear‐thinning nature of clay‐rich suspensions. Large current ripples and low‐amplitude bed‐waves are likely to be common in the fringe of other submarine fans. The presence and spatial trends in mixed sand–mud bedform types may be an important tool in interpreting fan fringe environments

    An Avatar-Led Digital Smoking Cessation Program for Sexual and Gender Minority Young Adults: Intervention Development and Results of a Single-Arm Pilot Trial

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    BACKGROUND: Sexual and gender minority young adults have a high prevalence of smoking and unique barriers to accessing tobacco treatment. OBJECTIVE: To address these challenges as well as their preferences for sexual and gender minority-targeted interventions and digital programs, we developed and evaluated the acceptability, preliminary efficacy, and impact on theory-based change processes of an acceptance and commitment therapy-based digital program called Empowered, Queer, Quitting, and Living (EQQUAL). METHODS: Participants (n=22) of a single-arm trial conducted to evaluate the program were young adults, age 18 to 30 years, who self-identified as sexual and gender minority individuals and smoked at least one cigarette per day. All participants received access to the EQQUAL program. Participants completed web-based surveys at baseline and at a follow-up 2 months after enrollment. We verified self-reported smoking abstinence with biochemical testing; missing data were counted as smoking or using tobacco. RESULTS: For young adults who logged in at least once (n=18), the mean number of log-ins was 5.5 (SD 3.6), mean number of sessions completed was 3.1 (SD 2.6), and 39% (7/18) completed all 6 sessions. Overall, 93% of participants (14/15) were satisfied with the EQQUAL program, 100% (15/15) found it easy to use, and 100% (15/15) said it helped them be clearer about how to quit. Abstinence from smoking or using tobacco was confirmed with biochemical testing for 23% of participants (5/22). Both quantitative and qualitative results suggested a positive overall response to the avatar guide, with areas for future improvement largely centered on the avatar\u27s appearance and movements. CONCLUSIONS: Treatment acceptability of EQQUAL was very promising. The rate of abstinence, which was biochemically confirmed, was 3 times higher than that of the only other digital program to date that has targeted sexual and gender minority young adults and 6 to 13 times higher than those of nontargeted digital smoking interventions among sexual and gender minority young adults. Planned improvements for the next iteration of the program include making the avatar\u27s movements more natural; offering multiple avatar guides with different on characteristics such as race, ethnicity, and gender identity from which to choose; and providing a support forum for users to connect anonymously with peers

    On the relationship between mathematics and visuospatial processing in Turner syndrome

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    A common neurocognitive phenotype of Turner syndrome (TS) includes coincident deficits in math and visuospatial reasoning while overall IQ remains intact. However, research has highlighted disparities in the relationship between these properties in women with TS, suggesting that not all visuospatial domains are equally related to mathematics in this group. Here, we present findings from a longitudinal investigation of visuospatial processing and its relationship to math performance in adolescent girls with TS and age-matched healthy controls. Participants completed a standardized battery of math and visuospatial tests once a year for 4 years. Linear mixed effects modeling was used to examine the relationship between mathematics and each visuospatial domain over time. Our results indicate that math performance was related to visual tracking, visual-motor coordination, and figure-ground processing. Such visuospatial domains appear to be uniquely affected by TS and could contribute to their deficits in math performance. Furthermore, differences in math and visuospatial test performance between girls with TS and healthy controls remain stable over time. Our results have important implications for the role of visuospatial processing in early math performance and may inform the development of effective interventions aimed at improving math education in children with TS

    No Change in Perceptual or Chronotropic Outcome When Altering Preferred Step Frequency for a Short Duration

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    IIntroduction: Millions of individuals incorporate jogging into their physical activity routines as a leisurely pursuit and as a way to achieve positive health outcomes. People appear to choose jogging speed and the associated step frequency on pure, natural preference. Understandably, kinesthetics are important, but another important underlying factor is metabolic cost. The purpose of this work was to investigate if preferred step frequency (at a preferred jogging pace) also minimizes perceived effort (Borg Rating of Perceived Exertion, 6-20; RPE) and chronotropic stress (heart rate; HR) during a ten-minute activity bout when compared with step frequencies altered by 5%. Methods: Recreationally-trained male subjects underwent two testing visits. The first visit was used to establish RPE and HR responses during a 10-minute jogging activity at preferred speed and step frequency. On a subsequent visit, between two and four days later, with preferred speed maintained, subjects were guided by metronome to strike at either 95% or 105% of their preferred step frequency. The 10-minute runs were randomized, crossed-over, and separated by 20 minutes. RPE and HR were analyzed by repeated measures ANOVA. Results: Fourteen subjects (age: 21.1 ± 0.95; body mass index: 23.2 ± 2.5) enrolled. Preferred jogging speed (speed. 6.4 ± 1.0 miles per hour; 10.2 ± 1.6 kilometers per hour) and step frequency (steps. 161.2 ± 10.3 steps/minute) were determined at the first visit, along with RPE (11.3 ± 1.7) and HR (166.4 ± 12.7). At the second visit, preferred speed was maintained while the frequency of foot-strike was altered. Neither differences in RPE (p = 0.252; 11.3 ± 1.7, 11.6 ± 1.9, 11.8 ± 1.5) nor HR (p = 0.547; 166.4 ± 12.7, 164.7 ± 14.9, 165.2 ± 15.3) were different when comparing the preferred, 95%, and 105% step frequency trials, respectively. Although anecdotal, some subjects verbalized displeasure with the change in pace and most all appeared to markedly alter the initial foot strike phase of the gait to meet the directed foot strike tempo. Discussion: Our data must be interpreted cautiously. While altering step frequency by 5% for a short duration does not appear to alter an individual’s RPE or HR appreciably, the result during longer duration activity may not be the same. In addition, the implications for biomechanical loading and metabolic cost were not presently investigated

    The Atacama Cosmology Telescope: The LABOCA/ACT Survey of Clusters at All Redshifts

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    We present a multi-wavelength analysis of eleven Sunyaev Zel'dovich effect (SZE)-selected galaxy clusters (ten with new data) from the Atacama Cosmology Telescope (ACT) southern survey. We have obtained new imaging from the Large APEX Bolometer Camera (345GHz; LABOCA) on the Atacama Pathfinder EXperiment (APEX) telescope, the Australia Telescope Compact Array (2.1GHz; ATCA), and the Spectral and Photometric Imaging Receiver (250, 350, and 500 Όm500\,\rm\mu m; SPIRE) on the Herschel Space Observatory. Spatially-resolved 345GHz SZE increments with integrated S/N > 5 are found in six clusters. We compute 2.1GHz number counts as a function of cluster-centric radius and find significant enhancements in the counts of bright sources at projected radii Ξ<Ξ2500\theta < \theta_{2500}. By extrapolating in frequency, we predict that the combined signals from 2.1GHz-selected radio sources and 345GHz-selected SMGs contaminate the 148GHz SZE decrement signal by ~5% and the 345GHz SZE increment by ~18%. After removing radio source and SMG emission from the SZE signals, we use ACT, LABOCA, and (in some cases) new Herschel SPIRE imaging to place constraints on the clusters' peculiar velocities. The sample's average peculiar velocity relative to the cosmic microwave background is 153±383 km s−1153\pm 383\,\rm km\,s^{-1}.Comment: 19 pages, 11 figures, Accepted for Publication in The Astrophysical Journa

    First Incursion of Salmonella enterica Serotype Typhimurium DT160 into New Zealand

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    An outbreak of human Salmonella enterica serotype Typhimurium DT160 infection in New Zealand was investigated from May to August 2001. Handling of dead wild birds, contact with persons with diarrheal illness, and consumption of fast food were associated with infection. Contaminated roof-collected rainwater was also detected

    The Atacama Cosmology Telescope: the stellar content of galaxy clusters selected using the Sunyaev-Zel'dovich effect

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    We present a first measurement of the stellar mass component of galaxy clusters selected via the Sunyaev-Zel'dovich (SZ) effect, using 3.6 um and 4.5 um photometry from the Spitzer Space Telescope. Our sample consists of 14 clusters detected by the Atacama Cosmology Telescope (ACT), which span the redshift range 0.27 < z < 1.07 (median z = 0.50), and have dynamical mass measurements, accurate to about 30 per cent, with median M500 = 6.9 x 10^{14} MSun. We measure the 3.6 um and 4.5 um galaxy luminosity functions, finding the characteristic magnitude (m*) and faint-end slope (alpha) to be similar to those for IR-selected cluster samples. We perform the first measurements of the scaling of SZ-observables (Y500 and y0) with both brightest cluster galaxy (BCG) stellar mass and total cluster stellar mass (M500star). We find a significant correlation between BCG stellar mass and Y500 (E(z)^{-2/3} DA^2 Y500 ~ M*^{1.2 +/- 0.6}), although we are not able to obtain a strong constraint on the slope of the relation due to the small sample size. Additionally, we obtain E(z)^{-2/3} DA^2 Y500 ~ M500star^{1.0 +/- 0.6} for the scaling with total stellar mass. The mass fraction in stars spans the range 0.006-0.034, with the second ranked cluster in terms of dynamical mass (ACT-CL J0237-4939) having an unusually low total stellar mass and the lowest stellar mass fraction. For the five clusters with gas mass measurements available in the literature, we see no evidence for a shortfall of baryons relative to the cosmic mean value.Comment: Accepted for publication in MNRAS; 12 pages, 10 figure

    New Generation of Educators Initiative: Transforming teacher preparation.

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    The focus of the New Generation of Educators Initiative (NGEI) was to answer the question "What would it take to transform teacher education?" From 2016 to 2019, with support from the S. D. Bechtel, Jr. Foundation, teacher education programs at 10 California State University (CSU) campuses partnered with local school districts to design and demonstrate innovative practices that could transform teacher preparation. This report documents the learnings from multiple participants in this transformative work, including Foundation program staff and representatives from partnerships between universities and school districts

    Multi-Messenger Gravitational Wave Searches with Pulsar Timing Arrays: Application to 3C66B Using the NANOGrav 11-year Data Set

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    When galaxies merge, the supermassive black holes in their centers may form binaries and, during the process of merger, emit low-frequency gravitational radiation in the process. In this paper we consider the galaxy 3C66B, which was used as the target of the first multi-messenger search for gravitational waves. Due to the observed periodicities present in the photometric and astrometric data of the source of the source, it has been theorized to contain a supermassive black hole binary. Its apparent 1.05-year orbital period would place the gravitational wave emission directly in the pulsar timing band. Since the first pulsar timing array study of 3C66B, revised models of the source have been published, and timing array sensitivities and techniques have improved dramatically. With these advances, we further constrain the chirp mass of the potential supermassive black hole binary in 3C66B to less than (1.65±0.02)×109 M⊙(1.65\pm0.02) \times 10^9~{M_\odot} using data from the NANOGrav 11-year data set. This upper limit provides a factor of 1.6 improvement over previous limits, and a factor of 4.3 over the first search done. Nevertheless, the most recent orbital model for the source is still consistent with our limit from pulsar timing array data. In addition, we are able to quantify the improvement made by the inclusion of source properties gleaned from electromagnetic data to `blind' pulsar timing array searches. With these methods, it is apparent that it is not necessary to obtain exact a priori knowledge of the period of a binary to gain meaningful astrophysical inferences.Comment: 14 pages, 6 figures. Accepted by Ap
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