TESTING FOR DISEQUILIBRIUM IN THE DEMAND FOR AGRICULTURAL INPUTS

A dynamic system of cost-share equations for agricultural inputs is used to test for the presence of input disequilibrium. This dynamic system incorporates a disequilibrium adjustment process into input-share equations derived from a translog cost function. The disequilibrium process is represented as a generalized partial adjustment model where disequilibrium in one input may affect other inputs. Results from this analysis suggest applications of translog share systems to agriculture under static equilibrium assumptions are inappropriate.Demand and Price Analysis, Research Methods/ Statistical Methods,

The neurochemical basis of photic entrainment of the circadian pacemaker

Circadian rhythmicity in mammals is controlled by the action of a light-entrainable hypothalamus, in association with two cell clusters known as the supra chiasmatic nuclei (SCN). In the absence of temporal environmental clues, this pacemaker continues to measure time by an endogenous mechanism (clock), driving biochemical, physiological, and behavioral rhythms that reflect the natural period of the pacemaker oscillation. This endogenous period usually differs slightly from 24 hours (i.e., circadian). When mammals are maintained under a 24 hour light-dark (LD) cycle, the pacemaker becomes entrained such that the period of the pacemaker oscillation matches that of the LD cycle. Potentially entraining photic information is conveyed to the SCN via a direct retinal projection, the retinohypothalamic tract (RHT). RHT neurotransmission is thought to be mediated by the release of excitatory amino acids (EAA) in the SCN. In support of this hypothesis, recent experiments using nocturnal rodents have shown that EAA antagonists block the effects of light on pacemaker-driven behavioral rhythms, and attenuate light induced gene expression in SCN cells. An understanding of the neurochemical basis of the photic entrainment process would facilitate the development of pharmacological strategies for maintaining synchrony among shift workers in environments, such as the Space Station, which provide unreliable or conflicting temporal photic clues

Does stimulant therapy help adult ADHD?

Central nervous system stimulants improve symptoms of attention deficit-hyperactivity disorder (ADHD) in adults (strength of recommendation: B, based on an older, inconclusive systematic review, a lesser-quality systematic review, and several newer small randomized controlled trials). Although not the focus of this question, nonstimulant medications (including buproprion, modafinil, and guanfacine) have also been studied in the treatment of ADHD in adults. Recently, atomoxetine became the only nonstimulant medication to receive approval by the US Food and Drug Administration for the treatment of ADHD

Artificial evolution for PET and SPECT reconstruction

International audienceWe propose an evolutionary approach for image reconstruction in nuclear medicine. Our method is based on a cooperative coevolution strategy (also called Parisian evolution): the "fly algorithm". Method and Materials: Each individual, or fly, corresponds to a 3D point that mimics a radioactive emitter, i.e. a stochastic simulation of annihilation events is performed to compute the fly's illumination pattern. For each annihilation, a photon is emitted in a random direction, and a second photon is emitted in the opposite direction. The line between two detected photons is called line of response (LOR). If both photons are detected by the scanner, the fly's illumination pattern is updated. The LORs of every fly are aggregated to form the population total illumination pattern. Using genetic operations to optimize the position of positrons, the population of flies evolves so that the population total pattern matches measured data. The final population of flies approximates the radioactivity concentration. Results: We have developed numerical phantom models to assess the reconstruction algorithm. To date, no scattering and no tissue attenuation have been considered. Whilst this is not physically correct, it allows us to test and validate our approach in the simplest cases. Preliminary results show the validity of this approach in both 2D and fully-3D modes. In particular, the size of objects, and their relative concentrations can be retrieved in the 2D mode. In fully-3D, complex shapes can be reconstructed. Conclusions: An evolutionary approach for PET reconstruction has been proposed and validated using simple test cases. Further work will therefore include the use of more realistic input data (including random events and scattering), which will finally lead to implement the correction of scattering within our algorithm. A comparison study against ML-EM and/or OS-EM methods will also need to be conducted

Rapport final de la Collaboration CERN-CNRS pour la construction du LHC: Accord Technique d'Exécution No 2 Cryostats et assemblage des sections droites courtes (SSS) du LHC

Depuis 1995 et suite à la signature du protocole de Collaboration, le CERN, le CEA et le CNRS ont étroitement collaboré dans le cadre de la contribution exceptionnelle de la France à la construction du LHC. Pour le CNRS, l'Institut de Physique Nucléaire d'Orsay a pris en charge deux Accords Techniques d'Exécution. Le premier concerne la conception et l'assemblage des Sections Droites Courtes de la machine, et le deuxième, l'étalonnage des thermomètres cryogéniques du LHC. Dans le cadre de l'Accord Technique d'Exécution N°2, le Bureau d'Etudes de la Division Accélérateur de l'IPNO et le groupe AT-CRI du CERN ont travaillé de concert pour mener à bien la conception des SSS (Short Straight Section) et de tous les équipements nécessaires à l'assemblage. Ce rapport a donc pour objectif de dresser, en termes d'historique, d'organisation, de résultats quantitatifs et qualitatifs et de moyens mis en ?uvre, un tableau aussi complet que possible du déroulement de cette Collaboration entre le CERN et le CNRS

Generative adversarial networks for augmenting training data of microscopic cell images

Generative adversarial networks (GANs) have recently been successfully used to create realistic synthetic microscopy cell images in 2D and predict intermediate cell stages. In the current paper we highlight that GANs can not only be used for creating synthetic cell images optimized for different fluorescent molecular labels, but that by using GANs for augmentation of training data involving scaling or other transformations the inherent length scale of biological structures is retained. In addition, GANs make it possible to create synthetic cells with specific shape features, which can be used, for example, to validate different methods for feature extraction. Here, we apply GANs to create 2D distributions of fluorescent markers for F-actin in the cell cortex of Dictyostelium cells (ABD), a membrane receptor (cAR1), and a cortex-membrane linker protein (TalA). The recent more widespread use of 3D lightsheet microscopy, where obtaining sufficient training data is considerably more difficult than in 2D, creates significant demand for novel approaches to data augmentation. We show that it is possible to directly generate synthetic 3D cell images using GANs, but limitations are excessive training times, dependence on high-quality segmentations of 3D images, and that the number of z-slices cannot be freely adjusted without retraining the network. We demonstrate that in the case of molecular labels that are highly correlated with cell shape, like F-actin in our example, 2D GANs can be used efficiently to create pseudo-3D synthetic cell data from individually generated 2D slices. Because high quality segmented 2D cell data are more readily available, this is an attractive alternative to using less efficient 3D networks

Elastic properties of highly anisotropic thin poly(propylene) foams

In this letter, elastic properties of highly anisotropic cellular poly(propylene) films are reported. The material shows peculiar elastic properties compared to other foams in the literature. The data is displayed as the relative Young's modulus $E^*/E_s$ versus relative density $\rho^*/\rho_s$. Almost all the data from the literature are located on the region $E^*/E_s=(\rho^*/\rho_s)^n$ with $1\le n\le6$. The introduced material on the other hand have lower relative Young's modulus at high relative densities, $n\ge6$

Tariff optimization in Networks

We consider the problem of determining a set of optimal tariffs for an agent in the network, who owns a subset of all the arcs, and who receives revenue by setting the tariffs on the arc he owns. Multiple rational clients are active in the network, who route their demands on the cheapest paths from source to destination. The cost of a path is determined by fixed costs and tariffs on the arcs of the path.We introduce a remodeling of the network, using shortest paths. We develop three algorithms, a path oriented mixed integer program and a known arc oriented mixed integer program. Combined with reduction methods this remodeling enables us to solve the problem to optimality, for quite large instances. We provide computational results for the methods developped and compare them with the results of the arc oriented mixed integer programming formulation of the problem, applied to the original network.Economics ;

What are effective treatments for oppositional and defiant behaviors in preadolescents?

Parent training is effective for treating oppositional and defiant behaviors (strength of recommendation [SOR]: A, based on systematic reviews). Parent training programs are standardized, short-term interventions that teach parents specialized strategies--including positive attending, ignoring, the effective use of rewards and punishments, token economies, and time out --to address clinically significant behavior problems. In addition to parent training, other psychosocial interventions are efficacious in treating oppositional and defiant behavior. To date, no studies have assessed the efficacy of medication in treating children with pure oppositional defiant disorder (ODD). However, studies have shown amphetamines to be effective for children with ODD and comorbid attention deficit/hyperactivity disorder (ADHD) (SOR: A, based on a meta-analysis)