Electronic Olfactory Sensor Based on A. mellifera Odorant‐Binding Protein 14 on a Reduced Graphene Oxide Field‐Effect Transistor

An olfactory biosensor based on a reduced graphene oxide (rGO) field‐effect transistor (FET), functionalized by the odorant‐binding protein 14 (OBP14) from the honey bee (Apis mellifera) has been designed for the in situ and real‐time monitoring of a broad spectrum of odorants in aqueous solutions known to be attractants for bees. The electrical measurements of the binding of all tested odorants are shown to follow the Langmuir model for ligand–receptor interactions. The results demonstrate that OBP14 is able to bind odorants even after immobilization on rGO and can discriminate between ligands binding within a range of dissociation constants from K_d=4 μM to K_d=3.3 mM . The strongest ligands, such as homovanillic acid, eugenol, and methyl vanillate all contain a hydroxy group which is apparently important for the strong interaction with the protein.     

Cohen–Macaulayness and Limit Behavior of Depth for Powers of Cover Ideals

Let 𝕂 be a field, and let R = 𝕂[x ₁,…, x _n ] be the polynomial ring over 𝕂 in n indeterminates x ₁,…, x _n . Let G be a graph with vertex-set {x ₁,…, x _n }, and let J be the cover ideal of G in R. For a given positive integer k, we denote the kth symbolic power and the kth bracket power of J by J ^(k) and J ^[k], respectively. In this paper, we give necessary and sufficient conditions for R/J ^k , R/J ^(k), and R/J ^[k] to be Cohen–Macaulay. We also study the limit behavior of the depths of these rings.     

Neutron-neutron correlation approach for 11Li halo structure investigation

The preemission of neutrons from ¹¹Li halo nuclei is considered. The present problems of investigation of ¹¹Li halo nucleus structure by means of the C _nn correlation function are briefly presented. The influence of the target screening on the halo neutron preemission is described. It is shown that, owing to the diminishing of the screening effect, the yield of preemission neutron pairs is expected to be much larger in the case of ¹²C than in the case of Si target. It is shown that a new experiment on a ¹²C target will allow one to solve the standing problems of C _nn and to test experimentally a recent new theory of C _nn. The text was submitted by the authors in English.     

Gauge fixing procedure in the extended BRST theory. The example of the abelian 2‐forms

The paper proposes a general procedure to find the form of the gauge fixing term in the extended BRST quantization of the gauge theories, a difficult problem in the standard approach. Our proposal is based on the many level structure of the extended spaces and leads to a simple form of the gauge fixing term. The abelian 2‐form model is completely analyzed as an example.     

Estimation of the mesoscopic thermoplastic dissipation in High-Cycle FatigueEstimation de la dissipation thermoplastique en fatigue à grand nombre de cycles

A series of High-Cycle Fatigue (HCF) criteria for polycrystalline materials is based on a multiscale interpretation, proposed initially by Dang Van, in which the principal concepts are a two scales model and a shakedown condition. The purpose of this Note is to extend the study of the different dissipative regimes during cyclic loading within this framework by using a self consistent homogenization scheme in coupled thermoplasticity. It is shown that the Sachs and Lin-Taylor schemes are not able to represent the thermal evolutions observed during fatigue tests. To cite this article: E. Charkaluk, A. Constantinescu, C. R. Mecanique 334 (2006).     

Predicting air quality: Improvements through advanced methods to integrate models and measurements

Air quality prediction plays an important role in the management of our environment. Computational power and efficiencies have advanced to the point where chemical transport models can predict pollution in an urban air shed with spatial resolution less than a kilometer, and cover the globe with a horizontal resolution of less than 50 km. Predicting air quality remains a challenge due to the complexity of the governing processes and the strong coupling across scales. While air quality prediction is closely aligned with weather prediction, there are important differences, including the role of pollution emissions and their associated large uncertainties. Improvements in air quality prediction require a close integration of observations. As more atmospheric chemical observations become available chemical data assimilation is expected to play an essential role in air quality forecasting. In this paper advances in air quality forecasting are discussed with an emphasis on data assimilation. Applications of the four-dimensional variational method (4D-Var) and the ensemble Kalman filter (EnKF) approach are presented and the computation challenges are discussed.     

Electron crystallization and bifurcation theory

The bifurcation of periodic solutions is a necessary, but not a sufficient, condition for electron crystallization. Consequently, the crystallization domain in phase space may be considerably smaller than the bifurcation domain.     

Boundary values of analytic functions

It is known that a complex — valued continuous functionS(x) as well as a Schwartz distribution on the real axis can be extended in the complex plane minus the support ofS to an analytic function?(z). In the case of a continuous function the jump of?(z) on the real axis represents exactlyS(x): $$\mathop {\lim }\limits_{\varepsilon \to 0 + } [\hat S(x + i\varepsilon ) - \hat S(x - i\varepsilon )] = S(x)$$ . We call regular a pointx on the support ofS such that \(\mathop {\lim }\limits_{\varepsilon \to 0 + } [\hat S(x + i\varepsilon ) - \hat S(x - i\varepsilon )]\) exists. Conditions are found for the existence of regular points on the support of a distribution. It is possible to call this limit (if this exists) the valueS(x) of the distributionS in the pointx. Properties of this type occur in the theory of dispersion relations.     

Vacuum polarization in magnetic field

The dispersive properties of free space in the presence of a magnetic field are calculated in the lowest order in the fine-structure constant, but exactly in the field. An integral representation of the corresponding index of refraction is written, exhibiting the dispersive and birefringent properties of the vacuum, with absorption coming in for transverse photon momenta above the pair production threshold. The weak-field limit and the dominant behavior in strong fields are explicitly calculated.