8,384 research outputs found
To what extent would the poorest consumers nutritionally and socially benefit from a global food tax and subsidy reform ? A framed field experiment based on daily food intake
In this paper we propose a new method in experimental economics, designed to evaluate the effectiveness of public policy incentives aimed at altering consumer behaviors. We apply this method to wide-ranging policies on food prices, which use subsidies to increase the consumption of healthy products and taxes to reduce that of unhealthy ones. Our protocol allows for observation of an individualâs daily food consumption before and after the policy. We examine two separate policies: the one subsidizes fruit and vegetables, while the other one combines taxes and subsidies. We measure their nutritional and economic impacts on the choices of low-income French consumers, compared to a reference group. Both policies have a positive effect on the nutritional quality of food choices of the two groups but initial gaps widen, especially with the subsidies. In the low-income group this can be explained by an initially unfavorable pattern and by weaker price elasticities. The redistributive effects are therefore doubly regressive. Moreover, the individual price elasticities, that the experimental approach enables us to measure, show widely diverse behaviors. They are counter-effective for close to 40% of our sample of poor women.OBESITY;PUBLIC POLICY;SOCIAL INEQUALITIES;POVERTY;INCOME REDISTRIBUTION;REGRESSIVE TAX;INDIVIDUALIZED PRICE INDEX;NUTRITIONAL TAX SYSTEM;FOOD TAX
A frequency-adjustable electromagnet for hyperthermia measurements on magnetic nanoparticles
We describe a low-cost and simple setup for hyperthermia measurements on
colloidal solutions of magnetic nanoparticles (ferrofluids) with a
frequency-adjustable magnetic field in the range 5-500 kHz produced by an
electromagnet. By optimizing the general conception and each component (nature
of the wires, design of the electromagnet), a highly efficient setup is
obtained. For instance, in a useful gap of 1.1 cm, a magnetic field of 4.8 mT
is generated at 100 kHz and 500 kHz with an output power of 3.4 W and 75 W,
respectively. A maximum magnetic field of 30 mT is obtained at 100 kHz. The
temperature of the colloidal solution is measured using optical fiber sensors.
To remove contributions due to heating of the electromagnet, a differential
measurement is used. In this configuration the sensitivity is better than 1.5
mW at 100 kHz and 19.3 mT. This setup allows one to measure weak heating powers
on highly diluted colloidal solutions. The hyperthermia characteristics of a
solution of Fe nanoparticles are described, where both the magnetic field and
the frequency dependence of heating power have been measured
On Being Bound Thereby
Part of Symposium: The United States Constitution (rev. ed.) How would you rewrite the United States Constitution
Temporal Imperialism
Issues of time and temporality pervade American constitutional adjudication, at both a doctrinal and a broader, structural level. The doctrinal issue concerns the extent to which judicial decisions operate forward, backward, or some combination of both across time. The structural issue concerns the related and overarching question of how the Supreme Court, as a court, operates in time, and the temporal division of authority between courts and legislatures. In both contexts, the Supreme Court is an actor in time. This Article examines the Courtâs treatment of temporal issues through three case studies: (1) a pair of early decisions in which the Court confronted both the transition from the colonial to the republican constitutional regime, and the temporal scope of legislative acts; (2) the Courtâs twentieth-century doctrine on adjudicative retroactivity; and (3) the recent case of Grutter v. Bollinger, in which the Courtâs temporal imperialism led it to claim ever-greater power to define the relevant timeframe for antidiscrimination law. The Courtâs institutional self-presentation suggests that it is immortal and therefore not temporally bound, and that claim of continuity typically extends to its decisions. But the causal flow from institutional to doctrinal continuity sometimes breaks down. Perhaps not surprisingly, these moments of disjunction tend to arise when the Court chooses to allow them to. Even in situations that call into question the continuity of a particular doctrine, therefore, the Court remains master of time in that it as an institution determines when and how the façade of doctrinal continuity is to be breached
High Dimensional Classification with combined Adaptive Sparse PLS and Logistic Regression
Motivation: The high dimensionality of genomic data calls for the development
of specific classification methodologies, especially to prevent over-optimistic
predictions. This challenge can be tackled by compression and variable
selection, which combined constitute a powerful framework for classification,
as well as data visualization and interpretation. However, current proposed
combinations lead to instable and non convergent methods due to inappropriate
computational frameworks. We hereby propose a stable and convergent approach
for classification in high dimensional based on sparse Partial Least Squares
(sparse PLS). Results: We start by proposing a new solution for the sparse PLS
problem that is based on proximal operators for the case of univariate
responses. Then we develop an adaptive version of the sparse PLS for
classification, which combines iterative optimization of logistic regression
and sparse PLS to ensure convergence and stability. Our results are confirmed
on synthetic and experimental data. In particular we show how crucial
convergence and stability can be when cross-validation is involved for
calibration purposes. Using gene expression data we explore the prediction of
breast cancer relapse. We also propose a multicategorial version of our method
on the prediction of cell-types based on single-cell expression data.
Availability: Our approach is implemented in the plsgenomics R-package.Comment: 9 pages, 3 figures, 4 tables + Supplementary Materials 8 pages, 3
figures, 10 table
Quadruplexes In âDictyâ: Crystal Structure Of A Four-Quartet G-Quadruplex Formed By G-Rich Motif Found In The Dictyostelium Discoideum Genome
Guanine-rich DNA has the potential to fold into non-canonical G-quadruplex (G4) structures. Analysis of the genome of the social amoeba Dictyostelium discoideum indicates a low number of sequences with G4-forming potential (249â1055). Therefore, D. discoideum is a perfect model organism to investigate the relationship between the presence of G4s and their biological functions. As a first step in this investigation, we crystallized the dGGGGGAGGGGTACAGGGGTACAGGGG sequence from the putative promoter region of two divergent genes in D. discoideum. According to the crystal structure, this sequence folds into a four-quartet intramolecular antiparallel G4 with two lateral and one diagonal loops. The G-quadruplex core is further stabilized by a G-C WatsonâCrick base pair and a AâTâA triad and displays high thermal stability (Tm \u3e 90°C at 100 mM KCl). Biophysical characterization of the native sequence and loop mutants suggests that the DNA adopts the same structure in solution and in crystalline form, and that loop interactions are important for the G4 stability but not for its folding. Four-tetrad G4 structures are sparse. Thus, our work advances understanding of the structural diversity of G-quadruplexes and yields coordinates for in silico drug screening programs and G4 predictive tools
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