3,950 research outputs found
The causes of full ocean depth interannual variability in Drake Passage
In recent years a number of large scale modes of Southern Hemisphere climate variability have been observed, most notably the Southern Annular Mode (SAM, e.g. Thompson and Solomon, 2002), the Pacific South American modes (PSA, e.g. Mo and Peagle, 2001), the Antarctic Dipole (e.g. Martinson and Ianuzzi, 2003), the Antarctic Circumpolar Wave (e.g. White and Peterson, 1996), and of course the El Niño Southern Oscillation (ENSO). All have pronounced effects over or in the Southern Ocean, and may be expected to account for a significant part of the interannual variability observed there. Most studies analyse these phenomena from a large-scale point of view, often by extracting modes from Southern Hemisphere atmospheric and oceanic fields using various mathematical techniques. In this study we have taken an alternative approach, and tried to understand the causes of the full ocean depth variability in Drake Passage observed in the WOCE SR1b repeat hydrographic sections (Cunningham et al. 2003)
The Freezeout Hypersurface at LHC from particle spectra: Flavor and Centrality Dependence
We extract the freezeout hypersurface in Pb-Pb collisions at 2760 GeV at the CERN Large Hadron Collider by analysing the data on
transverse momentum spectra within a unified model for chemical and kinetic
freezeout. The study has been done within two different schemes of freezeout,
single freezeout where all the hadrons freezeout together versus double
freezeout where those hadrons with non-zero strangeness content have different
freezeout parameters compared to the non-strange ones. We demonstrate that the
data is better described within the latter scenario. We obtain a strange
freezeout hypersurface which is smaller in volume and hotter compared to the
non-strange freezeout hypersurface for all centralities with a reduction in
around . We observe from the extracted parameters that
the ratio of the transverse size to the freezeout proper time is invariant
under expansion from the strange to the non-strange freezeout surfaces across
all centralities. Moreover, except for the most peripheral bins, the ratio of
the non-strange and strange freezeout proper times is close to .Comment: Final version accepted for publicatio
Is preparation for end of life associated with pre-death grief in caregivers of people with dementia?
OBJECTIVES: Family caregivers of people with dementia can experience loss and grief before death. We hypothesized that modifiable factors indicating preparation for end of life are associated with lower pre-death grief in caregivers. DESIGN: Cross-sectional. SETTING: Caregivers of people with dementia living at home or in a care home. PARTICIPANTS: In total, 150 caregivers, 77% female, mean age 63.0 (SD = 12.1). Participants cared for people with mild (25%), moderate (43%), or severe dementia (32%). MEASUREMENTS: Primary outcome: Marwit-Meuser Caregiver Grief Inventory Short Form (MMCGI-SF). We included five factors reflecting preparation for end of life: (1) knowledge of dementia, (2) social support, (3) feeling supported by healthcare providers, (4) formalized end of life documents, and (5) end-of-life discussions with the person with dementia. We used multiple regression to assess associations between pre-death grief and preparation for end of life while controlling for confounders. We repeated this analysis with MMCGI-SF subscales ("personal sacrifice burden"; "heartfelt sadness"; "worry and felt isolation"). RESULTS: Only one hypothesized factor (reduced social support) was strongly associated with higher grief intensity along with the confounders of female gender, spouse, or adult child relationship type and reduced relationship closeness. In exploratory analyses of MMCGI-SF subscales, one additional hypothesized factor was statistically significant; higher dementia knowledge was associated with lower "heartfelt sadness." CONCLUSION: We found limited support for our hypothesis. Future research may benefit from exploring strategies for enhancing caregivers' social support and networks as well as the effectiveness of educational interventions about the progression of dementia (ClinicalTrials.gov ID: NCT03332979)
Cr-Mo-V-W: A new refractory and transition metal high-entropy alloy system
Cr-Mo-V-W high-entropy alloy (HEA) is studied, with 2553 K equilibrium solidus and high Cr content to promote protective oxide scale formation, suggesting potential applications in hot, oxidising environments. Alloy Search and Predict (ASAP) and phase diagram calculations found a single phase, body-centred cubic (BCC) solid solution at elevated temperatures, across the range of compositions present within the system - uncommon for a HEA of refractory and transition metals. Density functional theory identified solubility of 22 at.% Cr at solidus temperature, with composition-dependent drive for segregation during cooling. An as-cast, BCC single-phase with the composition 31.3Cr-23.6Mo-26.4 V-18.7 W exhibiting dendritic microsegregation was verified
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Optimal initial position and technique for the front foot contact phase of cricket fast bowling: commonalities between individual-specific simulations of elite bowlers
Group-based and individual-based studies in cricket fast bowling have identified common technique characteristics associated with ball release speed. The applicability of these findings to individual bowlers is often questioned, however, due to research approach limitations. This study aims to identify whether the optimal initial body position at front foot contact and subsequent technique to maximise ball release speed exhibit common characteristics for elite male cricket fast bowlers using individual-specific computer optimisations. A planar 16-segment whole-body torque-driven simulation model of the front foot contact phase of fast bowling was customised, evaluated, and the initial body position and subsequent movement pattern optimised, for ten elite male fast bowlers. The optimised techniques significantly increased ball release speed by 4.8 ± 1.3 ms−1 (13.5 ± 4.1%) and ranged between 37.8 and 42.9 ms−1, and in lower peak ground reaction forces and loading rates. Common characteristics were observed within the optimal initial body position with more extended front knees, as well as more flexion of the front and bowling arm shoulders than in current performances. Delays to the onset of trunk flexion, front arm and bowling arm shoulder extension, and wrist flexion were also common in the subsequent movement during the front foot contact phase. Lower front hip extensor and front shoulder flexor torques, as well as greater bowling shoulder extensor torques were also evident. This is useful knowledge for coach development, talent identification, and coaching practice
Boundaries of Disk-like Self-affine Tiles
Let be a disk-like self-affine tile generated by an
integral expanding matrix and a consecutive collinear digit set , and let be the characteristic polynomial of . In the
paper, we identify the boundary with a sofic system by
constructing a neighbor graph and derive equivalent conditions for the pair
to be a number system. Moreover, by using the graph-directed
construction and a device of pseudo-norm , we find the generalized
Hausdorff dimension where
is the spectral radius of certain contact matrix . Especially,
when is a similarity, we obtain the standard Hausdorff dimension where is the largest positive zero of
the cubic polynomial , which is simpler than
the known result.Comment: 26 pages, 11 figure
Human hippocampal theta oscillations reflect sequential dependencies during spatial planning
Movement-related theta oscillations in rodent hippocampus coordinate ‘forward sweeps’ of location-specific neural activity that could be used to evaluate spatial trajectories online. This raises the possibility that increases in human hippocampal theta power accompany the evaluation of upcoming spatial choices. To test this hypothesis, we measured neural oscillations during a spatial planning task that closely resembles a perceptual decision-making paradigm. In this task, participants searched visually for the shortest path between a start and goal location in novel mazes that contained multiple choice points, and were subsequently asked to make a spatial decision at one of those choice points. We observed ~4–8 Hz hippocampal/medial temporal lobe theta power increases specific to sequential planning that were negatively correlated with subsequent decision speed, where decision speed was inversely correlated with choice accuracy. These results implicate the hippocampal theta rhythm in decision tree search during planning in novel environments
Problems in the treatment of malabsorption in CF
ABSTRACT. Several factors play a role in the cause of malabsorption in CF. Besides the enzyme deficiency in the secretion of the exocrine pancreas, decreased bile‐salt concentration in the gut may also be an important factor in the fat malabsorption. The contribution to the fat absorption by other lipases, such as lingual lipase and gastric lipase, remains to he proved. The therapeutic measures are only partly effective because of the breakdown of swalled enzymes by gastric acid. Some improvement is reached by using a new acid‐resistant coating for the enzyme supplement. Newly developed and essential for its success is the application of small coated particles to prevent retention in the stomach, and the easy breakdown of the coating in an alkaline solution. The treatment of the bile salt deficiency has not been successful until now. A trial with additional Tween 80, with the option of supplementing the detergent activity which was found to he successful in Crohn disease, was without marked success. Copyrigh
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