10,719 research outputs found
Geochemical characterization of supraglacial debris via in situ and optical remote sensing methods: a case study in Khumbu Himalaya, Nepal
Surface glacier debris samples and field spectra were collected from the ablation zones of Nepal Himalaya Ngozumpa and Khumbu glaciers in November and December 2009. Geochemical and mineral compositions of supraglacial debris were determined by X-ray diffraction and X-ray fluorescence spectroscopy. This composition data was used as ground truth in evaluating field spectra and satellite supraglacial debris composition and mapping methods. Satellite remote sensing methods for characterizing glacial surface debris include visible to thermal infrared hyper- and multispectral reflectance and emission signature identification, semi-quantitative mineral abundance indicies and spectral image composites. Satellite derived supraglacial debris mineral maps displayed the predominance of layered silicates, hydroxyl-bearing and calcite minerals on Khumbu Himalayan glaciers. Supraglacial mineral maps compared with satellite thermal data revealed correlations between glacier surface composition and glacier surface temperature. Glacier velocity displacement fields and shortwave, thermal infrared false color composites indicated the magnitude of mass flux at glacier confluences. The supraglacial debris mapping methods presented in this study can be used on a broader scale to improve, supplement and potentially reduce errors associated with glacier debris radiative property, composition, areal extent and mass flux quantifications
Spin-Echo Measurements for an Anomalous Quantum Phase of 2D Helium-3
Previous heat-capacity measurements of our group had shown the possible
existence of an anomalous quantum phase containing the zero-point vacancies
(ZPVs) in 2D He. The system is monolayer He adsorbed on graphite
preplated with monolayer He at densities () just below the 4/7
commensurate phase (). We carried out
pulsed-NMR measurements in order to examine the microscopic and dynamical
nature of this phase. The measured decay of spin echo signals shows the
non-exponential behaviour. The decay curve can be fitted with the double
exponential function, but the relative intensity of the component with a longer
time constant is small (5%) and does not depend on density and temperature,
which contradicts the macroscopic fluid and 4/7 phase coexistence model. This
slowdown is likely due to the mosaic angle spread of Grafoil substrate and the
anisotropic spin-spin relaxation time in 2D systems with respect to the
magnetic field direction. The inverse value deduced from the major echo
signal with a shorter time constant, which obeys the single exponential
function, decreases linearly with decreasing density from , supporting the
ZPV model.Comment: 4 pages, 6 figure
A massive, distant proto-cluster at z=2.47 caught in a phase of rapid formation?
Numerical simulations of cosmological structure formation show that the
Universe's most massive clusters, and the galaxies living in those clusters,
assemble rapidly at early times (2.5 < z < 4). While more than twenty
proto-clusters have been observed at z > 2 based on associations of 5-40
galaxies around rare sources, the observational evidence for rapid cluster
formation is weak. Here we report observations of an asymmetric, filamentary
structure at z = 2.47 containing seven starbursting, submillimeter-luminous
galaxies and five additional AGN within a comoving volume of 15000 Mpc.
As the expected lifetime of both the luminous AGN and starburst phase of a
galaxy is ~100 Myr, we conclude that these sources were likely triggered in
rapid succession by environmental factors, or, alternatively, the duration of
these cosmologically rare phenomena is much longer than prior direct
measurements suggest. The stellar mass already built up in the structure is
and we estimate that the cluster mass will exceed that
of the Coma supercluster at . The filamentary structure is in line
with hierarchical growth simulations which predict that the peak of cluster
activity occurs rapidly at z > 2.Comment: 7 pages, 3 figures, 2 tables, accepted in ApJL (small revisions from
previous version
Sex Differences in the Hemodynamic Response to Arm Elevation
Please view abstract in the attached PDF file
Data mining of portable EEG brain wave signals for sports performance analysis: An Archery case study
BACKGROUND ♦ Achievement in high performance sport requires an appropriate ‘state of mind’, which is trained alongside the physical skills. ♦ However, quantification of mental state during coaching is often difficult. ♦ With the advent of a new generation of portable compact EEGs and wireless eye tracking devices, one can measure the neurocognitive activity of an athlete’s brain and their visual focus simultaneously in ecologically representative training scenarios. AIM/OBJECTIVES ♦ We present evidence suggesting that the ‘state of mind’ of an athlete can be measured and compared with target-based performance measures. METHOD ♦ Measurements were taken from intermediate, county level, near elite and elite archers investigating: o quantification of EEG brain wave signals comparing archers of different abilities o correlation of EEG data across shots as a function of marksmanship o prototyping real-time EEG data feedback using sound during training o synchronous EEG and eye tracking ♦ Archery was chosen to demonstrate the real-time and in-situ quantification of neural activity compared with target-based measures of performance that archery provides, over a range of timespans and skills. ♦ Mental performance was explored during stages of a shot, across shots within a set, or across different sessions. RESULTS ♦ Results demonstrate that there are significant and measurable changes in EEG patterns during a shot with evidence suggesting that the patterns vary as a function of skill level, but not simply as a function of score. ♦ Significance of each of these outcomes for goal-directed learning and performance enhancement are discussed. DISCUSSION ♦ This may provide coaches and athletes with real-time EEG feedback to identify differing mental skill execution compared to a baseline or aspirational measurement from another athlete. ♦ Future work includes injury recovery/prevention and welfare, rehabilitation, and work with mobility-challenged non-athletes
Transdiagnostic treatment of bipolar disorder and comorbid anxiety using the Unified Protocol for Emotional Disorders: A pilot feasibility and acceptability trial
BACKGROUND
Comorbid anxiety in bipolar disorder (BD) is associated with greater illness severity, reduced treatment response, and greater impairment. Treating anxiety in the context of BD is crucial for improving illness course and outcomes. The current study examined the feasibility, acceptability and preliminary efficacy of the Unified Protocol (UP), a transdiagnostic cognitive behavioral therapy, as an adjunctive treatment to pharmacotherapy for BD and comorbid anxiety disorders.
METHODS
Twenty-nine patients with BD and at least one comorbid anxiety disorder were randomized to pharmacotherapy treatment-as-usual (TAU) or TAU with 18 sessions of the UP (UP+TAU). All patients completed assessments every four weeks to track symptoms, functioning, emotion regulation and temperament. Linear mixed-model regressions were conducted to track symptom changes over time and to examine the relationship between emotion-related variables and treatment response.
RESULTS
Satisfaction ratings were equivalent for both treatment groups. Patients in the UP+TAU group evidenced significantly greater reductions over time in anxiety and depression symptoms (Cohen's d's>0.80). Baseline levels of neuroticism, perceived affective control, and emotion regulation ability predicted magnitude of symptom change for the UP+TAU group only. Greater change in perceived control of emotions and emotion regulation skills predicted greater change in anxiety related symptoms.
LIMITATIONS
This was a pilot feasibility and acceptability trial; results should be interpreted with caution.
CONCLUSIONS
Treatment with the UP+TAU was rated high in patient satisfaction, and resulted in significantly greater improvement on indices of anxiety and depression relative to TAU. This suggests that the UP may be a feasible treatment approach for BD with comorbid anxiety.This work was supported by a Postdoctoral National Research Service Award from the National Institutes of Health [F32 MH098490] to K. Ellard. (F32 MH098490 - Postdoctoral National Research Service Award from the National Institutes of Health)Accepted manuscrip
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