2,025 research outputs found
Intersection Information based on Common Randomness
The introduction of the partial information decomposition generated a flurry
of proposals for defining an intersection information that quantifies how much
of "the same information" two or more random variables specify about a target
random variable. As of yet, none is wholly satisfactory. A palatable measure of
intersection information would provide a principled way to quantify slippery
concepts, such as synergy. Here, we introduce an intersection information
measure based on the G\'acs-K\"orner common random variable that is the first
to satisfy the coveted target monotonicity property. Our measure is imperfect,
too, and we suggest directions for improvement.Comment: 19 pages, 5 figure
Constraining Holocene hydrological changes in the CarpathianâBalkan region using speleothem δ18O and pollen-based temperature reconstructions
Here we present a speleothem isotope record (POM2) from AscunsÄ Cave (Romania) that provides new data on past climate changes in the CarpathianâBalkan region from 8.2 ka until the present. This paper describes an approach to constrain the effect of temperature changes on calcite δ18O values in stalagmite POM2 over the course of the middle Holocene (6â4 ka), and across the 8.2 and 3.2 ka rapid climate change events. Independent pollen temperature reconstructions are used to this purpose. The approach combines the temperature-dependent isotope fractionation of rain water during condensation and fractionation resulting from calcite precipitation at the given cave temperature. The only prior assumptions are that pollen-derived average annual temperature reflects average cave temperature, and that pollen-derived coldest and warmest month temperatures reflect the range of condensation temperatures of rain above the cave site. This approach constrains a range of values between which speleothem δ18O changes should be found if controlled only by surface temperature variations at the cave site. Deviations of the change in δ18Ocspel values from the calculated temperature-constrained range of change are interpreted towards large-scale variability of climateâhydrology.
Following this approach, we show that an additional âź0.6â° enrichment of δ18Oc in the POM2 stalagmite was caused by changing hydrological patterns in SW Romania across the middle Holocene, most likely comprising local evaporation from the soil and an increase in Mediterranean moisture δ18O. Further, by extending the calculations to other speleothem records from around the entire Mediterranean basin, it appears that all eastern Mediterranean speleothems recorded a similar isotopic enrichment due to changing hydrology, whereas all changes recorded in speleothems from the western Mediterranean are fully explained by temperature variation alone. This highlights a different hydrological evolution between the two sides of the Mediterranean.
Our results also demonstrate that during the 8.2 ka event, POM2 stable isotope data essentially fit the temperature-constrained isotopic variability. In the case of the 3.2 ka event, an additional climate-related hydrological factor is more evident. This implies a different rainfall pattern in the Southern Carpathian region during this event at the end of the Bronze Age
The Total Synthesis of (â)-Scabrolide A
The first total synthesis of the norcembranoid diterpenoid scabrolide A is disclosed. The route begins with the synthesis of two chiral pool-derived fragments, which undergo a convergent coupling to expediently introduce all 19 carbon atoms of the natural product. An intramolecular DielsâAlder reaction and an enoneâolefin cycloaddition/fragmentation sequence are then employed to construct the fused [5â6â7] linear carbocyclic core of the molecule and complete the total synthesis
A Gathering of Native American Healers: Exploring the Interface of Indigenous Tradition and Professional Practice
This article reports insights from a 4âday Gathering of Native American Healers at the University of Michigan in October of 2010. This event convened 18 traditional healers, clinically trained service providers, and crossâcultural mental health researchers for a structured group dialogue to advance professional knowledge about the integration of Indigenous healing practices and conventional mental health treatments in communityâbased mental health services for Native Americans. Our thematic analysis of transcripts from five Roundtable sessions afforded several key insights and understandings pertaining to the integration of Indigenous healing and conventional mental health services. First, with reference to traditional healing, the importance of a rampant relationality, various personal qualities, Indigenous spirituality, and maintenance of traditional life and culture were accentuated by Roundtable participants. Second, for traditional healers to practice effectively, Roundtable participants posited that these individuals must maintain personal wellness, cultivate profound knowledge of healing practices, recognize the intrinsic healing potential within all human beings, and work for the community rather than themselves. In speaking to the possibilities and challenges of collaboration between Indigenous and conventional biomedical therapeutic approaches, Roundtable participants recommended the implementation of cultural programming, the observance of mutuality and respect, the importance of clear and honest communication, and the need for awareness of cultural differences as unique challenges that must be collaboratively overcome.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116300/1/ajcp9747.pd
Surrogate model solver for impurity-induced superconducting subgap states
A simple impurity solver is shown to capture the impurity-induced
superconducting subgap states in quantitative agreement with the numerical
renormalization group and quantum Monte-Carlo simulations. The solver is based
on the exact diagonalization of a single-impurity Anderson model with
discretized superconducting reservoirs including only a small number of
effective levels. Their energies and couplings to the impurity -level are
chosen so as to best reproduce the Matsubara frequency dependence of the
hybridization function. We provide a number of critical benchmarks and
demonstrate the solvers efficiency in combination with the reduced basis method
[Phys. Rev. B 107, 144503 (2023)] by calculating the phase diagram for an
interacting three-terminal junction.Comment: 15 pages, 15 figure
Binder jet additive manufacturing of functional 4D components from NiMnGa magnetic shape memory alloy powders
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