384 research outputs found
Monotonic regression based on Bayesian P-splines: an application to estimating price response functions from store-level scanner data
Generalized additive models have become a widely used instrument for flexible regression analysis. In many practical situations, however, it is desirable to restrict the flexibility of nonparametric estimation in order to accommodate a presumed monotonic relationship between a covariate and the response variable. For example, consumers usually will buy less of a brand if its price increases, and therefore one expects a brand's unit sales to be a decreasing function in own price. We follow a Bayesian approach using penalized B-splines and incorporate the assumption of monotonicity in a natural way by an appropriate specification of the respective prior distributions. We illustrate the methodology in an empirical application modeling demand for a brand of orange juice and show that imposing monotonicity constraints for own- and cross-item price effects improves the predictive validity of the estimated sales response function considerably
Synthesis and Structural Investigation of Protonated Haloacetyl Fluorides
Herein, we report the O-monoprotonated species of chloroacetyl fluoride and fluoroacetyl fluoride in the binary superacidic systems HF/MF5 and DF/MF5 (M=As, Sb) as hexafluoridoarsenates and hexafluoridostibates. The colorless salts were characterized by low temperature vibrational spectroscopy, low temperature NMR spectroscopy and single-crystal X-ray diffraction. [CCIH2C(OH)F][SbF6] crystallizes in the monoclinic space group P2(1)/c with four formula units per unit cell and [CIH2FC-(OD)F][SbF6] in the triclinic space group P (1) over bar with two formula units per cell. The experimental data are discussed together with quantum chemical calculations at the omega B97XD/aug-cc-pVTZ-level of theory. Protonation leads to significant shortening of the C F bond due to back-donation of fluorine lone-pair electrons
Report on the First Working Group Meeting of the “AG Marketing”
This contribution reports on the first meeting of the new formed working group “Data Analysis and Classification in Marketing (AG Marketing)” of the data science society (GfKl) held at the KIT, Karlsruhe, November 14th – 15th, 2019. The abstracts of the presentations given reflect the ongoing trend to exploit a large variety of digital data sources for marketing purposes and the need for advanced and innovative analysis methods
Samarium Diiodide Acting on Acetone - Modeling Single Electron Transfer Energetics in Solution
Samarium diiodide is a versatile single electron transfer (SET) agent with various applications in organic chemistry. Lewis structures regularly insinuate the existence of a ketyl radical when samarium diiodide binds a carbonyl group. The study presented here investigates this electron transfer by the means of computational chemistry. All electron CASPT2 calculations with the inclusion of scalar relativistic effects predict an endotherm electron transfer from samarium diiodide to acetone. Energies calculated with the PBE0-D3(BJ) functional and a small core pseudopotential are in good agreement with CASPT2. The calculations confirm the experimentally measured increase of the samarium diiodide reduction potential through the addition of hexamethylphosphoramide also known as HMPA
Migraine-attributed burden, impact and disability, and migraine-impacted quality of life: Expert consensus on definitions from a Delphi process
Delphi; Migraine; DisabilityDelphi; Migraña; DiscapacidadDelphi; Migranya; DiscapacitatBackground
Migraine-attributed burden, impact, disability and migraine-impacted quality of life are important concepts in clinical management, clinical and epidemiological research, and health policy, requiring clear and agreed definitions. We aimed to formulate concise and precise definitions of these concepts by expert consensus.
Methods
We searched the terms migraine-attributed burden, impact, disability and migraine-impacted quality of life in Embase and Medline from 1974 and 1946 respectively. We followed a Delphi process to reach consensus on definitions.
Results
We found widespread conflation of concepts and inconsistent terminology within publications. Following three Delphi rounds, we defined migraine-attributed burden as “the summation of all negative consequences of the disease or its diagnosis”; migraine-attributed impact as “the effect of the disease, or its diagnosis, on a specified aspect of life, health or wellbeing”; migraine-attributed disability as “physical, cognitive and mental incapacities imposed by the disease”; and migraine-impacted quality of life as “the subjective assessment by a person with the disease of their general wellbeing, position and prospects in life”. We complemented each definition with a detailed description.
Conclusion
These definitions and descriptions should foster consistency and encourage more appropriate use of currently available quantifying instruments and aid the future development of others.The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was funded by Eli Lilly and Company
Municipal biowaste treatment plants contribute to the contamination of the environment with residues of biodegradable plastics with putative higher persistence potential
Biodegradable plastics (BDP) are expected to mineralize easily, in particular under conditions of technical composting. However, the complexity of the sample matrix has largely prevented degradation studies under realistic conditions. Here composts and fertilizers from state-of-the-art municipal combined anaerobic/aerobic biowaste treatment plants were investigated for residues of BDP. We found BDP fragments > 1 mm in significant numbers in the final composts intended as fertilizer for agriculture and gardening. Compared to pristine compostable bags, the recovered BDP fragments showed differences in their material properties, which potentially renders them less prone to further biodegradation. BDP fragments < 1 mm were extracted in bulk and came up to 0.43 wt% of compost dry weight. Finally, the liquid fertilizer produced during the anaerobic treatment contained several thousand BDP fragments < 500 µm per liter. Hence, our study questions, if currently available BDP are compatible with applications in areas of environmental relevance, such as fertilizer production
Common and heritable components of white matter microstructure predict cognitive function at 1 and 2 y
The integrity or microstructure of white matter as determined by diffusion tensor imaging (DTI) is related to cognitive function. Most studies focus on individual tracts, even though the microstructure of white matter tracts throughout the brain is highly correlated. In older adults, a common property of white matter predicts cognitive function, though it is not known if common factors are present in early childhood development or how they relate to cognitive function. Here, we found that DTI-based common underlying factors that emerge at this age are significantly related to cognitive abilities from birth to age 2 y. These findings indicate that the functional specialization of cognition and the anatomical differentiation of fibers cooccur in the neonatal and infant brain
Migraine-attributed burden, impact and disability, and migraine-impacted quality of life : Expert consensus on definitions from a Delphi process
Migraine-attributed burden, impact, disability and migraine-impacted quality of life are important concepts in clinical management, clinical and epidemiological research, and health policy, requiring clear and agreed definitions. We aimed to formulate concise and precise definitions of these concepts by expert consensus. We searched the terms migraine-attributed burden, impact, disability and migraine-impacted quality of life in Embase and Medline from 1974 and 1946 respectively. We followed a Delphi process to reach consensus on definitions. We found widespread conflation of concepts and inconsistent terminology within publications. Following three Delphi rounds, we defined migraine-attributed burden as "the summation of all negative consequences of the disease or its diagnosis"; migraine-attributed impact as "the effect of the disease, or its diagnosis, on a specified aspect of life, health or wellbeing"; migraine-attributed disability as "physical, cognitive and mental incapacities imposed by the disease"; and migraine-impacted quality of life as "the subjective assessment by a person with the disease of their general wellbeing, position and prospects in life". We complemented each definition with a detailed description. These definitions and descriptions should foster consistency and encourage more appropriate use of currently available quantifying instruments and aid the future development of other
Migraine-attributed burden, impact and disability, and migraine-impacted quality of life : Expert consensus on definitions from a Delphi process
Migraine-attributed burden, impact, disability and migraine-impacted quality of life are important concepts in clinical management, clinical and epidemiological research, and health policy, requiring clear and agreed definitions. We aimed to formulate concise and precise definitions of these concepts by expert consensus. We searched the terms migraine-attributed burden, impact, disability and migraine-impacted quality of life in Embase and Medline from 1974 and 1946 respectively. We followed a Delphi process to reach consensus on definitions. We found widespread conflation of concepts and inconsistent terminology within publications. Following three Delphi rounds, we defined migraine-attributed burden as "the summation of all negative consequences of the disease or its diagnosis"; migraine-attributed impact as "the effect of the disease, or its diagnosis, on a specified aspect of life, health or wellbeing"; migraine-attributed disability as "physical, cognitive and mental incapacities imposed by the disease"; and migraine-impacted quality of life as "the subjective assessment by a person with the disease of their general wellbeing, position and prospects in life". We complemented each definition with a detailed description. These definitions and descriptions should foster consistency and encourage more appropriate use of currently available quantifying instruments and aid the future development of other
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