2,482 research outputs found
An information approach to the dynamics in farm income: implications for farmland markets
The valuation of farmland is a perennial issue for agricultural policy, given its importance in the farm investment portfolio. Despite the significance of farmland values to farmer wealth, prediction remains a difficult task. This study develops a dynamic information measure to examine the informational content of farmland values and farm income in explaining the distribution of farmland values over time
Optimal uncertainty quantification for legacy data observations of Lipschitz functions
We consider the problem of providing optimal uncertainty quantification (UQ)
--- and hence rigorous certification --- for partially-observed functions. We
present a UQ framework within which the observations may be small or large in
number, and need not carry information about the probability distribution of
the system in operation. The UQ objectives are posed as optimization problems,
the solutions of which are optimal bounds on the quantities of interest; we
consider two typical settings, namely parameter sensitivities (McDiarmid
diameters) and output deviation (or failure) probabilities. The solutions of
these optimization problems depend non-trivially (even non-monotonically and
discontinuously) upon the specified legacy data. Furthermore, the extreme
values are often determined by only a few members of the data set; in our
principal physically-motivated example, the bounds are determined by just 2 out
of 32 data points, and the remainder carry no information and could be
neglected without changing the final answer. We propose an analogue of the
simplex algorithm from linear programming that uses these observations to offer
efficient and rigorous UQ for high-dimensional systems with high-cardinality
legacy data. These findings suggest natural methods for selecting optimal
(maximally informative) next experiments.Comment: 38 page
Adjusting for desert-dust-related biases in a climate data record of sea surface temperature
Atmospheric desert-dust aerosol, primarily from north Africa, causes negative biases
in remotely sensed climate data records of sea surface temperature (SST). Here, large-scale bias
adjustments are deduced and applied to the v2 climate data record of SST from the European Space
Agency Climate Change Initiative (CCI). Unlike SST from infrared sensors, SST measured in situ is
not prone to desert-dust bias. An in-situ-based SST analysis is combined with column dust mass
from the Modern-Era Retrospective analysis for Research and Applications, Version 2 to deduce
a monthly, large-scale adjustment to CCI analysis SSTs. Having reduced the dust-related biases,
a further correction for some periods of anomalous satellite calibration is also derived. The corrections
will increase the usability of the v2 CCI SST record for oceanographic and climate applications, such
as understanding the role of Arabian Sea SSTs in the Indian monsoon. The corrections will also pave
the way for a v3 climate data record with improved error characteristics with respect to atmospheric
dust aerosol
Gli3 Controls Corpus Callosum Formation by Positioning Midline Guideposts During Telencephalic Patterning
The corpus callosum (CC) represents the major forebrain commissure connecting the 2 cerebral hemispheres. Midline crossing of callosal axons is controlled by several glial and neuronal guideposts specifically located along the callosal path, but it remains unknown how these cells acquire their position. Here, we show that the Gli3 hypomorphic mouse mutant Polydactyly Nagoya (Pdn) displays agenesis of the CC and mislocation of the glial and neuronal guidepost cells. Using transplantation experiments, we demonstrate that agenesis of the CC is primarily caused by midline defects. These defects originate during telencephalic patterning and involve an up-regulation of Slit2 expression and altered Fgf and Wnt/β-catenin signaling. Mutations in sprouty1/2 which mimic the changes in these signaling pathways cause a disorganization of midline guideposts and CC agenesis. Moreover, a partial recovery of midline abnormalities in Pdn/Pdn;Slit2−/− embryos mutants confirms the functional importance of correct Slit2 expression levels for callosal development. Hence, Gli3 controlled restriction of Fgf and Wnt/β-catenin signaling and of Slit2 expression is crucial for positioning midline guideposts and callosal developmen
Dynamic rotor mode in antiferromagnetic nanoparticles
We present experimental, numerical, and theoretical evidence for a new mode
of antiferromagnetic dynamics in nanoparticles. Elastic neutron scattering
experiments on 8 nm particles of hematite display a loss of diffraction
intensity with temperature, the intensity vanishing around 150 K. However, the
signal from inelastic neutron scattering remains above that temperature,
indicating a magnetic system in constant motion. In addition, the precession
frequency of the inelastic magnetic signal shows an increase above 100 K.
Numerical Langevin simulations of spin dynamics reproduce all measured neutron
data and reveal that thermally activated spin canting gives rise to a new type
of coherent magnetic precession mode. This "rotor" mode can be seen as a
high-temperature version of superparamagnetism and is driven by exchange
interactions between the two magnetic sublattices. The frequency of the rotor
mode behaves in fair agreement with a simple analytical model, based on a high
temperature approximation of the generally accepted Hamiltonian of the system.
The extracted model parameters, as the magnetic interaction and the axial
anisotropy, are in excellent agreement with results from Mossbauer
spectroscopy
Reflecting on the reasons pros and cons coercive measures for patients in psychiatric and somatic care: The role of clinical ethics consultation. A pilot study
Background and aim: Coercive measures in patient care have come under criticism leading to implement guidelines dedicated to the reduction of coercion. This development of bringing to light clinical ethics support is hoped to serve as a means of building up awareness and potentially reducing the use of coercion. This study explores the specific features of ethics consultation (EC) while dealing with coercion. Material and method: Basel EC documentation presents insight to all persons involved with a case. The EC database of two Basel university hospitals was developed on the grounds of systematic screening and categorization by two reviewers. One hundred fully documented EC cases databased from 2013 to 2016 were screened for the discussion of coercive measures (somatic hospital and psychiatry: 50% cases). Results: Twenty-four out of 100 EC cases addressed coercion in relation to a clinically relevant question, such as compulsory treatment (70.8%), involuntary committal (50%), or restricting liberty (16.6%). Only 58.3% of EC requests mentioned coercion as an ethical issue prior to the meeting. In no case was patient decisional capacity given, capacity was impaired (43.5%), not given (33.3%), or unclear (21.7%; one not available). Discussion: As clinical staff appears sensitive to perceiving ethical uncertainty or conflict, but less prepared to articulate ethical concern, EC meetings serve to "diagnose" and "solve" the ethical focus of the problem(s) presented in EC. Patient decisional incapacity proved to be an important part of reasoning, when discussing the principle of harm prevention. While professional judgment of capacity remains unsystematic, rationality or even ethicality of decision making will be hampered. The documented EC cases show a variety of decisions about whether or not coercion was actually applied. Ethical reasoning on the competing options seemed to be instrumental for an unprejudiced decision complying with the normative framework and for building a robust consensus. Conclusions: The recommendation is whether EC should be used as a standard practice whenever coercion is an issue-ideally before coercion is applied, or otherwise. Moreover, more efforts should be made toward early and professional assessment of patient capacity and advance care counseling including the offer of advance directives
Comparison of [18F] NaF PET/CT dynamic analysis methods and a static analysis method including derivation of a semi-population input function for site-specific measurements of bone formation in a population with chronic kidney disease-mineral and bone disorder
The Clearance of Cyclosporine by Hemodialysis
The pharmacokinetics of cyclosporine were studied in five liver transplant patients when they were on and off hemodialysis. There was no significant difference in the blood clearance of cyclosporine between these two periods. Less than 1 per cent of the dose of cyclosporine was recovered in the dialysate. The mean dialysis clearance was less than 1 ml/min. This represents less than 1 per cent of the total blood clearance of cyclosporine. Dosage alterations of cyclosporine during or after hemodialysis do not appear to be necessary
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