USE OF STABLE ISOTOPES IN THE DETERMINATION OF THE MEAN ALTITUDE OF RECHARGE AND THE INVESTIGATION OF FUNCTION MECHANISM OF SPRING WATERS IN ARGOLIS PENINSULA (GREECE)

In the present study, the isotopic composition (δ18Ο) of several spring waters in Argolis peninsula is examined. The use of the specific isotope aimed at the determination of the altitude of recharge areas, while the credibility of the extracted results was verified by in situ geological observations. The applied methodology included the construction of a linear diagram which correlates the stable isotopic values (δ18Ο) in meteoric waters and the altitude. Isotopic data, concerning meteoric waters, came from: a) rain gauge stations of GNIP network (IAEA/WMO), b) rain tanks and selected wells located in Mt. Arachnaio, c) improvised rain collectors which were put in several sites in the peninsula. A decrease of 0.45‰ δ18Ο per 100m altitude was determined. The average isotopic composition of the examined springs, as far as δ18Ο is concerned, resulted from 14 sampling periods between October 2005 and March 2008. This 18O-content of spring waters was used to derive the recharge area and consequently to evaluate the mechanism of water renewal

Effect of Postharvest Application of Carvone on Potato Tubers Grown from True Potato Seed (TPS)

AbstractDormancy duration is an important quality aspect of both ware and seed potato tubers and may be extended by the application of chemical sprout suppressants. The replacement of these synthetic compounds by essential oils with sprouting-inhibitory properties may contribute to the sustainable cultivation of potato.The aim of this study was to examine how the postharvest application of carvone affects potato tubers grown from true potato seed (hybrid CIP IP 88008). Ten days after harvest, tubers were placed in air-tight glass containers and carvone was applied repeatedly (300mL/1000kg tubers) while untreated tubers were used for the control. The containers were stored at 5, 10 and 20°C and opened every two days for 10minutes for aeration. The number of sprouts per tuber, rate of respiration, fresh weight loss and concentration of glucose, fructose and sucrose in tuber tissue from the buds (‘eyes’) and the parenchyma were recorded.Carvone application did not affect bud dormancy duration at 5°C and buds did not sprout even after 98 days’ storage. At 10 and 20°C, carvone application prolonged dormancy, but at 20°C a high percentage of rotted tubers (40%) was observed. At all storage temperatures, carvone reduced weight loss but increased the rate of tuber respiration. Carvone application did not affect sugar content at 5οC, but after 68 days of storage at 10οC the concentration of fructose increased and sucrose decreased. However, after 4 months of storage no differences in sugar concentration were recorded.It is concluded that carvone application can effectively prolong bud dormancy during storage at 10οC. Even though the concentration of reducing sugars and the tuber respiration rate increased, there were no negative effects on the quality aspects of tubers (concentration of glucose, fructose and sucrose) after long term storage

Polynomial Growth Harmonic Functions on Finitely Generated Abelian Groups

In the present paper, we develop geometric analytic techniques on Cayley graphs of finitely generated abelian groups to study the polynomial growth harmonic functions. We develop a geometric analytic proof of the classical Heilbronn theorem and the recent Nayar theorem on polynomial growth harmonic functions on lattices \mathds{Z}^n that does not use a representation formula for harmonic functions. We also calculate the precise dimension of the space of polynomial growth harmonic functions on finitely generated abelian groups. While the Cayley graph not only depends on the abelian group, but also on the choice of a generating set, we find that this dimension depends only on the group itself.Comment: 15 pages, to appear in Ann. Global Anal. Geo

A fluorescence microscopy-based protocol for volumetric measurement of lysolecithin lesion-associated de- and re-myelination in mouse brain

Lysolecithin injections into the white matter tracts of the central nervous system are a valuable tool to study remyelination, but evaluating the resulting demyelinating lesion size is challenging. Here, we present a protocol to consistently measure the volume of demyelination and remyelination in mice following brain lysolecithin injections. We describe serial sectioning of the lesion, followed by the evaluation of the demyelinated area in two-dimensional images. We then detail the computation of the volume using our own automated iPython script

Reactivity to AQP4 epitopes in relapsing–remitting multiple sclerosis

Autoantibodies against the water channel AQP4, expressed predominately in central nervous system astrocytes, are markers and pathogenic factors in Devic's disease. In this study we examined whether Multiple Sclerosis (MS) patients recognize antigenic epitopes on AQP4 that may define distinct disease subsets. We screened sera from 45 patients with relapsing–remitting MS (RRMS) and 13 patients with primary progressive MS (PMS). 23 Neuromyelitis Optica (NMO) patients previously characterized were used as assay positive/negative controls. Sera from 23 patients with Systemic Lupus Erythematosus, 23 with primary Sjogren syndrome without neurological involvement and from 28 healthy individuals were also used as controls. NMO-positive sera exhibited reactivity against the intracellular epitope AQPaa252-275, confirming previous observations. All RRMS sera tested negative for anti-AQP4 antibodies using a cell-based assay, but surprisingly, 13% of them reacted with the epitope AQPaa252-275. PMS, healthy and disease controls showed no specific reactivity. Whether these antibodies define distinct MS subsets and have a pathogenic potential pointing to convergent pathogenetic mechanism with NMO, or are simply markers of astrocytic damage, remains to be determined

Performances of Anode-resistive Micromegas for HL-LHC

Micromegas technology is a promising candidate to replace Atlas forward muon chambers -tracking and trigger- for future HL-LHC upgrade of the experiment. The increase on background and pile-up event probability requires detector performances which are currently under studies in intensive RD activities. We studied performances of four different resistive Micromegas detectors with different read-out strip pitches. These chambers were tested using \sim120 GeV momentum pions, at H6 CERN-SPS beam line in autumn 2010. For a strip pitch 500 micrometers we measure a resolution of \sim90 micrometers and a efficiency of ~98%. The track angle effect on the efficiency was also studied. Our results show that resistive techniques induce no degradation on the efficiency or resolution, with respect to the standard Micromegas. In some configuration the resistive coating is able to reduce the discharge currents at least by a factor of 100.Micromegas technology is a promising candidate to replace Atlas forward muon chambers -tracking and trigger- for future HL-LHC upgrade of the experiment. The increase on background and pile-up event probability requires detector performances which are currently under studies in intensive RD activities. We studied performances of four different resistive Micromegas detectors with different read-out strip pitches. These chambers were tested using \sim120 GeV momentum pions, at H6 CERN-SPS beam line in autumn 2010. For a strip pitch 500 micrometers we measure a resolution of \sim90 micrometers and a efficiency of \sim98%. The track angle effect on the efficiency was also studied. Our results show that resistive techniques induce no degradation on the efficiency or resolution, with respect to the standard Micromegas. In some configuration the resistive coating is able to reduce the discharge currents at least by a factor of 100.Comment: "Presented at the 2011 Hadron Collider Physics symposium (HCP-2011), Paris, France, November 14-18 2011, 3 pages, 6 figures.

Kν10.1 K⁺ - channel plasma membrane discrete domain partitioning and its functional correlation in neurons

AbstractKV10.1 potassium channels are implicated in a variety of cellular processes including cell proliferation and tumour progression. Their expression in over 70% of human tumours makes them an attractive diagnostic and therapeutic target. Although their physiological role in the central nervous system is not yet fully understood, advances in their precise cell localization will contribute to the understanding of their interactions and function. We have determined the plasma membrane (PM) distribution of the KV10.1 protein in an enriched mouse brain PM fraction and its association with cholesterol- and sphingolipid-rich domains. We show that the KV10.1 channel has two different populations in a 3:2 ratio, one associated to and another excluded from Detergent Resistant Membranes (DRMs). This distribution of KV10.1 in isolated PM is cholesterol- and cytoskeleton-dependent since alteration of those factors changes the relationship to 1:4. In transfected HEK-293 cells with a mutant unable to bind Ca2+/CaM to KV10.1 protein, Kv10.1 distribution in DRM/non-DRM is 1:4. Mean current density was doubled in the cholesterol-depleted cells, without any noticeable effects on other parameters. These results demonstrate that recruitment of the KV10.1 channel to the DRM fractions involves its functional regulation

Power Law in Hadron Production

In high energy p+p(bar) interactions the mean multiplicity and transverse mass spectra of neutral mesons from eta to Upsilon (m = 0.5 - 10 GeV/c^2) and the transverse mass spectra of pions (m_T > 1 GeV/c^2) reveal a remarkable behaviour: they follow, over more than 10 orders of magnitude, the power-law function:The parameters C and P are energy dependent, but similar for all mesons produced at the same collision energy. This scaling resembles that expected in the statistical description of hadron production: the parameter P plays the role of a temperature and the normalisation constant C is analogous to the system volume. The fundamental difference is, however, in the form of the distribution function. In order to reproduce the experimental results and preserve the basic structure of the statistical approach the Boltzmann factor e^(-E/T) appearing in standard statistical mechanics has to be substituted by a power-law factor (E/Lambda)^(-P).Comment: significantly revised version to appear in Phys. Lett.