Trace Element Composition of Stream Sediments an Integrating Factor for Water Quality

Bottom sediments, suspended sediments, and water were sampled along 130 miles of the Buffalo River in northern Arkansas. The water and acid extracts of the suspended sediments and the minus 95 mesh fraction of the bottom sediments were analyzed by atomic absorption spectrometry. All samples were analyzed for Na, K, Mg, Ca, Zn, Cd, Cu, Pb, Fe, Co, Cr, Ni, and Mn. Selected bottom samples also were analyzed by As, Hg, and Zr. Zr was determined by x-ray fluorescence. Li and Sr were determined for selected water and suspended sediment samples. There is a general decrease downstream in Fe, Cu, Cr, Ni, Mn, Pb, K, and Na in the bottom sediments as the drainage area increases in carbonate rock and decreases in shale. The elements Mg, Ca, Zn, and Cd increase in bottom sediments downstream. The values for these elements in the water, especially the major elements, also correspond closely with the geology of the region. Tributaries are sites of abrupt rise and fall of metal values, within a few miles, from background to anomalously high values to background, especially tributaries draining Zn and Pb mineralized areas. The bottom sediments are mainly quartz and chert grains. These grains apparently are coated with hydrous iron oxide which acts as a sorbent for many of the elements and is a dominant transport mechanism for acid extractable Co, Cr, Ni, Cu, Mn, and K. Other acid extractable metals, particularly Mg, Ca, Zn, Cd, and Pb, are mostly in clastic grains. Graphic representation of the Langmuir equation for Mn is consistent with adsorption of Mn by iron in both bottom sediments and suspended sediments. On the basis of the volume of water collected, all the elements except Fe are more concentrated in the water than in the suspended sediments. Fe concentration of the suspended sediments increases with increasing flow because the suspended load is increased. The Mn/Fe ratio of the suspended sediments is approximately equal to or greater than that of the bottom sediments. The Mn/Fe ratio of suspended sediments relative to that of the bottom sediments increases downstream, possibly because of an autocatalytic effect of Mn precipitation. The relationship between sediment and water concentrations is not clear from the data because of the restricted concentration ranges for some elements in the suspended sediment and water. The sediment from the Buffalo River can be used to estimate grossly the concentration of elements in the water

Investigating microstructural variation in the human hippocampus using non-negative matrix factorization

In this work we use non-negative matrix factorization to identify patterns of microstructural variance in the human hippocampus. We utilize high-resolution structural and diffusion magnetic resonance imaging data from the Human Connectome Project to query hippocampus microstructure on a multivariate, voxelwise basis. Application of non-negative matrix factorization identifies spatial components (clusters of voxels sharing similar covariance patterns), as well as subject weightings (individual variance across hippocampus microstructure). By assessing the stability of spatial components as well as the accuracy of factorization, we identified 4 distinct microstructural components. Furthermore, we quantified the benefit of using multiple microstructural metrics by demonstrating that using three microstructural metrics (T1-weighted/T2-weighted signal, mean diffusivity and fractional anisotropy) produced more stable spatial components than when assessing metrics individually. Finally, we related individual subject weightings to demographic and behavioural measures using a partial least squares analysis. Through this approach we identified interpretable relationships between hippocampus microstructure and demographic and behavioural measures. Taken together, our work suggests non-negative matrix factorization as a spatially specific analytical approach for neuroimaging studies and advocates for the use of multiple metrics for data-driven component analyses

“Live Sun Smart!” Testing the effectiveness of a sun safety program for middle schoolers

Background: Skin cancer is a well-recognized public health issue, and primary prevention is the most effective strategy for reducing skin cancer risk. The current recommendations are that behavioral counseling for sun safety measures is most beneficial and effective for children and adolescents and that targeting this population at primary and middle schools is the ideal intervention strategy to increase sun-protective behaviors and reduce UV exposure, sunburn incidence, and formation of new moles. Numerous studies on the effectiveness of school-based sun safety interventions among elementary and middle school students have shown an increase in sun safety knowledge, attitudes, and behaviors following the intervention. Objective: To conduct a pilot feasibility study of “Live Sun Smart!,” (LSS) a school-based, multicomponent, interactive sun safety presentation, at changing sun safety knowledge, attitudes, and behaviors among middle school students. Methods: A non-randomized, single-group pretest-posttest interventional pilot study of the LSS program among children enrolled in grade 6. Results: After exposure to LSS, participants were more likely to give correct answers to knowledge-based sun safety questions and to report negative attitudes toward tanning. Minimal and not significant changes were found in self-reported sun safety behaviors, though students did report an intention to change behaviors following the intervention. Participants were satisfied with the program and believed it increased their sun safety knowledge. Conclusion: Live Sun Smart! appears to be an effective school-based, multicomponent sun safety program for improving sun safety knowledge and attitudes toward tanning among middle school students in this initial test of it. The strengths and weaknesses of this pilot study have implications for future research

Attachment Stability and Longitudinal Prediction of Psychotic-like Symptoms in Community Adolescents over Four Months of COVID-19 Pandemic

Background: The Friends and Family Interview (FFI) is assumed to be a valid method to study attachment stability and attachment-related psychopathological processes in adolescence, but no studies have yet tested the test–retest reliability of this interview or the longitudinal association of attachment patterns in response to the FFI from adolescents with symptoms such as psychotic-like experiences (e.g., hallucinations, bizarre behavior, dissociation, self-harm) that are known to have increased during the COVID-19 pandemic. Methods: This study involved 102 community adolescents (M = 14.64, SD = 1.63, 46% males) assessed twice: during a severe COVID-19-related lockdown (in Italy) (T1) and four months later (T2). Measures were the FFI (assessing attachment patterns: secure-autonomous, insecure-dismissing, insecure-preoccupied, and insecure-disorganized) and the thought problems scale of the Youth Self-Report to assess psychotic-like symptoms. Results: revealed high stability of four-way attachment classifications over four months (93.5%), with a modest yet significant link between higher disorganization at T1 and higher scores of thought problems at T2, p = 0.010. Conclusions: The FFI shows high test–retest reliability and can be a valid, age-adapted option to assess adolescents’ attachment. Attachment disorganization should be further investigated as possibly related to psychotic-like experiences in community adolescents

Is the Tsallis entropy stable?

The question of whether the Tsallis entropy is Lesche-stable is revisited. It is argued that when physical averages are computed with the escort probabilities, the correct application of the concept of Lesche-stability requires use of the escort probabilities. As a consequence, as shown here, the Tsallis entropy is unstable but the thermodynamic averages are stable. We further show that Lesche stability as well as thermodynamic stability can be obtained if the homogeneous entropy is used as the basis of the formulation of non-extensive thermodynamics. In this approach, the escort distribution arises naturally as a secondary structure.Comment: 6 page

The Automatic Real-Time GRB Pipeline of the 2-m Liverpool Telescope

The 2-m Liverpool Telescope (LT), owned by Liverpool John Moores University, is located in La Palma (Canary Islands) and operates in fully robotic mode. In 2005, the LT began conducting an automatic GRB follow-up program. On receiving an automatic GRB alert from a Gamma-Ray Observatory (Swift, INTEGRAL, HETE-II, IPN) the LT initiates a special override mode that conducts follow-up observations within 2-3 min of the GRB onset. This follow-up procedure begins with an initial sequence of short (10-s) exposures acquired through an r' band filter. These images are reduced, analyzed and interpreted automatically using pipeline software developed by our team called "LT-TRAP" (Liverpool Telescope Transient Rapid Analysis Pipeline); the automatic detection and successful identification of an unknown and potentially fading optical transient triggers a subsequent multi-color imaging sequence. In the case of a candidate brighter than r'=15, either a polarimetric (from 2006) or a spectroscopic observation (from 2007) will be triggered on the LT. If no candidate is identified, the telescope continues to obtain z', r' and i' band imaging with increasingly longer exposure times. Here we present a detailed description of the LT-TRAP and briefly discuss the illustrative case of the afterglow of GRB 050502a, whose automatic identification by the LT just 3 min after the GRB, led to the acquisition of the first early-time (< 1 hr) multi-color light curve of a GRB afterglow.Comment: PASP, accepted (8 pages, 3 figures

Vacuum spacetimes with a spacelike, hypersurface-orthogonal Killing vector: reduced equations in a canonical frame

The Newman-Penrose equations for spacetimes having one spacelike Killing vector are reduced -- in a geometrically defined "canonical frame'' -- to a minimal set, and its differential structure is studied. Expressions for the frame vectors in an arbitrary coordinate basis are given, and coordinate-independent choices of the metric functions are suggested which make the components of the Ricci tensor in the direction of the Killing vector vanish.Comment: 13 pages, no figures, LaTeX, to be published in Class. Quantum Gravity; v2: added/rephrased content, corrected typos, changed 1 referenc

Programming and supervision of resistance training leads to positive effects on strength and body composition: results from two randomised trials of community fitness programmes

Background: Many sedentary adults have high body fat along with low fitness, strength, and lean body mass (LBM) which are associated with poor health independently of body mass. Physical activity can aid in prevention, management, and treatment of numerous chronic conditions. The potential efficacy of resistance training (RT) in modifying risk factors for cardiovascular and metabolic disease is clear. However, RT is under researched in public health. We report community-based studies of RT in sedentary (Study 1), and overweight and pre-diabetic (Study 2) populations. Trial Design: Study 1: A semi-randomised trial design. Study 2: A randomised wait-list controlled trial. Methods: Study 1 (48-weeks): Participants choosing either a fitness centre approach, and randomised to structured-exercise (STRUC, n=107), or free/unstructured gym use (FREE, n=110), or not, and randomised to physical-activity-counselling (PAC, n=71) or a measurement only comparator (CONT, n=76). Study 2 (12-weeks): Patients were randomly assigned to; traditional-supervised-exercise (STRUC, n=30), physical-activity-counselling (PAC, n=23), either combined (COMB, n=39), or a wait-list comparator (CONT, n=54). Outcomes for both were BF mass (kg), LBM (kg), BF percentage (%), and strength. Results: Study 1: One-way ANCOVA revealed significant between group effects for BF% and LBM, but not for BF mass or strength. Post hoc paired comparisons revealed significantly greater change in LBM for the STRUC group compared with the CONT group. Within group changes using 95%CIs revealed significant changes only in the STRUC group for both BF% (-4.1 to -0.9%) and LBM (0.1 to 4.5 kg), and in FREE (8.2 to 28.5 kg) and STRUC (5.9 to 26.0 kg) for strength. Study 2: One-way ANCOVA did not reveal significant between group effects for strength, BF%, BF mass, or LBM. For strength, 95%CIs revealed significant within group changes for the STRUC (2.4 to 14.1 kg) and COMB (3.7 to 15.0 kg) groups. Conclusion: Strength increased in both studies across all RT treatments compared to controls, yet significant improvements in both strength and body-composition occurred only in programmed and/or supervised RT. As general increases in physical activity have limited impact upon body-composition, public health practitioners should structure interventions to include progressive RT. Keywords: Resistance Training, Body Composition, Exercise Treatment, Health Status

RISE: a fast-readout imager for exoplanet transit timing

By the precise timing of the low amplitude (0.005 - 0.02 magnitude) transits of exoplanets around their parent star it should be possible to infer the presence of other planetary bodies in the system down to Earth-like masses. We describe the design and construction of RISE, a fast-readout frame transfer camera for the Liverpool Telescope designed to carry out this experiment. The results of our commissioning tests are described as well as the data reduction procedure necessary. We present light curves of two objects, showing that the desired timing and photometric accuracy can be obtained providing that autoguiding is used to keep the target on the same detector pixel for the entire (typically 4 hour) observing run.Comment: Published in PROC SPIE, vol 7014, 70416