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Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels belong to the superfamily of voltage-gated pore loop channels. HCN channels are unique among vertebrate voltage-gated ion channels, in that they have a reverse voltage-dependence that leads to activation upon hyperpolarization. In addition, voltage-dependent opening of these channels is directly regulated by the binding of cAMP. HCN channels are encoded by four genes (HCN1–4) and are widely expressed throughout the heart and the central nervous system. The current flowing through HCN channels, designated Ih or If, plays a key role in the control of cardiac and neuronal rhythmicity (“pacemaker current”). In addition, Ih contributes to several other neuronal processes, including determination of resting membrane potential, dendritic integration and synaptic transmission. In this review we give an overview on structure, function and regulation of HCN channels. Particular emphasis will be laid on the complex roles of these channels for neuronal function and cardiac rhythmicity. [ABSTRACT FROM AUTHOR]

A research procedure is proposed which aims to analyse the agricultural spatial dynamics during the last thirty years using two levels of organisation of farming activity: the agricultural production system and the cropping system. Based on methods of statistical mapping and data mining, this procedure involves modelling the diversity of production systems and cropping systems (crop successions and sequences of cultural practices for each crop) in the form of classes independently of their localisation within the basin. It identifies homogeneous regions made up of groups of contiguous agricultural districts which exhibit similar combinations of production systems, crop successions or cultural practices during a given period of time. The results show a major increase in arable farms since 1970 at the expense of dairy farms and mixed cropping/livestock. This trend however appeared to be greatly spatially differentiated according to the agricultural districts, since livestock remained important on the edges of the basin, whereas it practically disappeared in its centre. The crop successions practiced in the basin and the cultural practices used on them also appear to be spatially differentiated, although the link to the production systems is not always clear. Thus it appears pertinent to combine the analysis of the two levels of organisation of the agriculture (methods of land use described by the concept of cropping system, and also the production systems into which the cropping systems fit) in the context of an environmental problem. [Copyright &y& Elsevier]

Abstract: Our novel type of magnetic angle sensor is based on Hall elements, signal electronics and the co-integration of a ferromagnetic concentrator (IMC technology). Instead of transforming a sin and a cos signal into angle information, requiring significant computing power, we use in a purely analog way the reversible ratio of two non-orthogonal measurement axes to provide a linear response over 120° of angle. The sensor is very robust to temperature drift and ageing effects and features a −3dB bandwidth of about 8kHz. [Copyright &y& Elsevier]

A residual offset lower than 0.2 mT is obtained with a CMOS integrated vertical Hall (VH)-sensor microsystem. Instead of the conventional design with five contacts in the sensor active area, we apply a layout with only four contacts. This design shows a higher effectiveness for the offset reduction by the spinning current (SC) method, because of the symmetrical current flow for the two different biasing phases. Furthermore, to obtain very low offsets, coupled sensors are integrated with the spinning current electronics in the final microsystem. A sensitivity up to Sv=0.025 V/VT is achieved for these sensors without any additional technology step. The measured output noise level of the integrated microsystem (1.9 μT/Hz) is in the usual range of commercial integrated Hall-sensors. Our new developments open the way to the realization of compact, low-cost angular sensors with 10 bit resolution. [Copyright &y& Elsevier]

The STN switching mechanism is governed by elastic constant ratios K33/K11 and K22/K11 (K11,K22 and K33 are respectively the splay, twist and bend elastic constants). This work explores the limitation of K22/K11 and how this can be translated into material/mixture design. The visco-elastic parameters K11, K22, ηsplay and γ1, were measured by dynamic light scattering (DLS) for three mixtures, based respectively on cyanobiphenyls, phenylbenzoates and dicyclohexyls with birefringence Δn ranging from 0.05 to 0.2. This study confirms that K22 and K11 only show slight variation for these mixtures; therefore, the ratio of K22/K11 remains remarkably constant and cannot be exploited in material design. In contrast, the twist and splay viscosities are directly related to the composition of the mixtures. Strongly polar nematic liquid crystals, such as the cyanobiphenyls, exhibit higher rotational viscosity coefficients. This work also outlines the dependence of the measurement accuracy of the visco-elastic parameters on the birefringence of the material investigated. [ABSTRACT FROM AUTHOR]

OBJECTIVE: According to Traditional Chinese Medicine (TCM) acupuncture is a suitable treatment for complex chronic diseases such as bronchial asthma. In a randomized, controlled study we investigated immunologic effects of Chinese acupuncture on patients with allergic asthma. PATIENTS AND METHODS: The effects of acupuncture treatment given according to the principles of TCM (TCM group, n = 20) were compared with those of acupuncture treatment using points not specific for asthma (control group, n = 18). All patients were treated 12 times for 30 minutes over a time period of 4 weeks. Patients' general well-being and several peripheral blood parameters (eosinophils, lymphocyte subpopulations, cytokines, in vitro lymphocyte proliferation) were determined before and after acupuncture treatment. RESULTS: In the TCM group, significantly more patients indicated an improvement in general well-being (79% in the TCM group versus 47% in the control group; p = 0.049) after acupuncture treatment. The following changes were found in the TCM group: within the lymphocyte subpopulations the CD3+ cells (p = 0.005) and CD4+ cells (p = 0.014) increased significantly. There were also significant changes in cytokine concentrations: interleukin (IL)-6 (p = 0.026) and IL-10 (p = 0.001) decreased whereas IL-8 (p = 0.050) rose significantly. Additionally, the in vitro lymphocyte proliferation rate increased significantly (p = 0.035) while the number of eosinophils decreased from 4.4% to 3.3% after acupuncture (p > 0.05). The control group, however, showed no significant changes apart from an increase in the CD4+ cells (p = 0.012). CONCLUSION: The results imply that asthma patients benefit from acupuncture treatment given in addition to conventional therapy. Furthermore, acupuncture performed in accordance with the principles of TCM showed significant immune-modulating effects. [ABSTRACT FROM AUTHOR]

Describes a silicon-based temperature stabilized axial Hall probe with an absolute accuracy of +/-40 ppm in the range from 0 to 6 T. Hall probe configuration; Magnetic field configuration; Calibration procedure.

• The approach characterises and quantifies crop management types. • The approach is appropriate for large extent case studies. • Spatial units are built to allocate crop managements for environmental modelling. • National statistics and local knowledge are combined to describe crop managements. • 900 crop managements are described on the 18 major crops of the Seine basin. Changes in agricultural land use over recent decades have exacerbated the pressures and impacts of agriculture on the environment. Researchers model these pressures and impacts using data on soils, climate and agricultural land use characteristics, which have to be represented at the spatial and temporal scales appropriate to the ecological or biophysical processes being studied. Representation of agricultural land use across large areas (several thousand of km2 or more) is hampered by lack of data on the diversity of farming practices and their spatial distribution, usually reduced to land cover. We propose in this article a methodological approach for combining generic and local information sources to characterise, across a large area, the diversity of crop managements and their spatial distribution, at a resolution appropriate to a specific environmental issue: assessment of nitrate contamination of groundwater. The approach involves four steps: (i) devise a system of spatial units that is appropriate to the research context and the available information sources, (ii) use multivariate analysis to characterise the diversity of crop managements obtained from a national database, (iii) conduct a survey, holding semi-directive interviews with experts and local actors to identify specific features that may locally modify this diversity, (iv) synthesise the statistical findings and survey results to establish a set of representative crop management "types". Illustrated in connection with the problem of diffuse nitrogen pollution of groundwater in the Seine-Normandie basin in France, it enabled to describe 919 crop managements out of the 18 main crops in the basin and especially highlighted the high diversity of practices on wheat with more than 200 crop managements. The knowledge produced on the diversity of crop managements and their spatial distribution was used for environmental modelling. [ABSTRACT FROM AUTHOR]

Abstract: We have developed a knowledge discovery system based on high-order hidden Markov models for analyzing spatio-temporal data bases. This system, named CarrotAge , takes as input an array of discrete data – the rows represent the spatial sites and the columns the time slots – and builds a partition together with its a posteriori probability. CarrotAge has been developed for studying the cropping patterns of a territory. It uses therefore an agricultural drench database, named Ter-Uti , which records every year the land-use category of a set of sites regularly spaced. The results of CarrotAge are interpreted by agronomists and used in research works linking agricultural land use and water management. Moreover, CarrotAge can be used to find out and study crop sequences in large territories, that is a main question for agricultural and environmental research, as discussed in this paper. [Copyright &y& Elsevier]

The effects of Cognac polyphenolic compounds (CPC) on aorta and isolated heart, the consequences of oral administration on haemodynamic parameters, vascular reactivity and cardiac recovery after ischaemia were investigated. CPC induced an endothelium-dependent vasorelaxation on rat-isolated aorta. This effect was prevented by the nitric oxide (NO) synthase inhibitor, NG-nitro- l-arginine-methyl ester, but not by the cyclo-oxygenase inhibitor, indomethacin, suggesting the implication of NO pathway. On isolated rat hearts, CPC induced positive inotropic, chronotropic, and lusitropic effect at 10−4–10−2 g/L while at 10−1 g/L, it had negative lusitropic effect and other parameters returned to baseline values. Oral administration of 40 mg/kg of CPC for 2 weeks did not modify systolic blood pressure and heart rate of rats throughout the treatment. CPC treatment did not affect ex vivo response of isolated thoracic aorta either to the contractile agent noradrenaline or to the endothelial-relaxant agent, acetylcholine. Isolated hearts from treated rats were submitted to 30-min global ischaemia followed by 120 min of reperfusion. Post-ischaemic recovery of functional cardiac parameters was not modified by treatment with CPC. Infarct size measured after the reperfusion in heart from CPC-treated rats was significantly decreased in comparison with hearts from control group. We conclude that in vitro, CPC had NO-dependent vasorelaxant effects and stimulated cardiac function. Oral treatment with CPC appeared to have no impact in vivo on blood pressure, heart rate of the rats or on cardiac contractility ex vivo; however, it could decrease the infarct size after an ischaemia–reperfusion. [ABSTRACT FROM AUTHOR]

To explore the evolution of a human impacted river, the Seine (France), over the 21st century, three driving factors were examined: climate, agriculture, and point source inputs of domestic and industrial origin. Three future scenarios were constructed, by modification of a baseline representative of recent conditions. A climate change scenario, based on simulations by a general circulation model driven by the SRES-A2 scenario of radiative forcing, accounts for an average warming of +3. 3 °C over the watershed and marked winter increase and summer decrease in precipitation. To illustrate a possible reduction in nitrate pollution from agricultural origin, a scenario of good agricultural practices was considered, introducing catch crops and a 20% decrease in nitrogen fertilisation. Future point source pollution was estimated following the assumptions embedded in scenario SRES-A2 regarding demographic, economic and technologic changes, leading to reductions of 30 to 75% compared to 2000, depending on the pollutants. Four models, addressing separate components of the river system (agronomical model, hydrogeological model, land surface model and water quality model), were used to analyse the relative impact of these scenarios on water quality, in light of their impact on hydrology and crop production. The first-order driving factor of water quality over the 21st century is the projected reduction of point source pollution, inducing a noticeable decrease in eutrophication and oxygen deficits downstream from Paris. The impact of climate change on these terms is driven by the warming of the water column. It enhances algal growth in spring and the loss factors responsible for phytoplankton mortality in late summer (grazers and viruses). In contrast, increased seasonal contrasts in river discharge have a negligible impact on river water quality, as do the changes in riverine nitrate concentration, which never gets limiting. The latter changes have a similar magnitude under the three scenarios. Under climate change, riverine and groundwater nitrate concentrations increase and crop production is advantaged with reduced growing cycles and increased yields. In contrast, nitrate concentrations decrease under the good agricultural practices scenario, with a limited decrease in crop production. When these two scenarios are combined, the changes in nitrate concentrations balance each other and crop yields increase. The results of this numerical exercise indicate that the potential changes to the Seine River system during the 21st century will not lead to severely degraded water quality. [Copyright &y& Elsevier]

A software package is presented here to predict the fate of nitrogen fertilizers and the transport of nitrate from the rooting zone of agricultural areas to surface water and groundwater in the Seine basin, taking into account the long residence times of water and nitrate in the unsaturated and aquifer systems. Information on pedological characteristics, land use and farming practices is used to determine the spatial units to be considered. These data are converted into input data for the crop model STICS which simulates the water and nitrogen balances in the soil–plant system with a daily time-step. A spatial application of STICS has been derived at the catchment scale which computes the water and nitrate fluxes at the bottom of the rooting zone. These fluxes are integrated into a surface and groundwater coupled model MODCOU which calculates the daily water balance in the hydrological system, the flow in the rivers and the piezometric variations in the aquifers, using standard climatic data (rainfall, PET). The transport of nitrate and the evolution of nitrate contamination in groundwater and to rivers is computed by the model NEWSAM. This modelling chain is a valuable tool to predict the evolution of crop productivity and nitrate contamination according to various scenarios modifying farming practices and/or climatic changes. Data for the period 1970–2000 are used to simulate the past evolution of nitrogen contamination. The method has been validated using available data bases of nitrate concentrations in the three main aquifers of the Paris basin (Oligocene, Eocene and chalk). The approach has then been used to predict the future evolution of nitrogen contamination up to 2015. A statistical approach allowed estimating the probability of transgression of different concentration thresholds in various areas in the basin. The model is also used to evaluate the cost of the damage resulting of the treatment of drinking water at the scale of a groundwater management unit in the Seine river basin. [Copyright &y& Elsevier]