1,310 research outputs found

    Potency Of N-Mderalization In 2 Kinds Of Forest Soils

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    ABSTRAK Penelitian ini dilaksanakan untukmengukur potensi mineralisasi nitrogen secara in vitro pada tanah hutan di bawah tegakan hutan Matebashii (Pasania edulis) dan Sudajii (Castanopsis cuspidata van Siebaldi) yang terletak di Propinsi Chiba, Jepang Potensi mineralisasi tanah hutan dihitung dengan menggunakan model kinetik sederhana secara in vitro pada inkubator yang mempunyai suhu 20°C, 25°C dan 30°C. Kadar NO3 dan NH: dianalisis secara periodik selama dalam inkubasi. Mineralisasi pada suhu 30°C ternyata lebih besar bila dibanding dengan pada 20°C dan 25°C untukMatebashii, tetapi tidakterialuberbeda untuk Sudajii. Mineralisasi tahunan untuk tanah hutan pada kedalaman 5 cm di bawah tegakan Matebashii hanya sebesar 78,92 kg.ha-1.th-1, atau hanya sekitar 50% dari mineralisasi N di bawah tegakan Sudajii (156,6 kg.ha-1.yr1). Karena potensi mineralisasi N pada tegakan Matebashii(No= 40,07 mg.100g-1tanah) adalah lebih rendahbila dibandingkan pada Sudajii (No= 43,11 mg.100etanah), maka energi aktivasinya (Ea=15.990 Ical.mo1-1) lebih tinggi bila dibanding dengan Sudajii (Ea= 6.072 kal.mo1-1). Konstanta laju mineralisasi pada tegakan Matehashii (k= 0.006 per hari) mempunyai nilai yang lebih rendah daripada di Sudajii (k= 0.011 per hari). Pengaruh pemanasan global menyebabkan Day at Temperature Standard (DTS) pada tegakan Matebashii akan meningkat 42% dart DTS pada tegakan Sudajii akan meningkat 12%. Dengandenulcian, mineralisasi N pada tegakan Matebashii di daerahpalingutara akan meningkat 17%. Meskipun mineralisasi N pada tegakan Sudajii 2X lebih banyak dibandingkan pada tegakan Matebashii, tetapi pengaruh pemanasan global hanya akan mening,katkan 2% saja. Kata kunci: mineralisasi nitrogen, tanah hutan, in vitro, suhu, pemanasan global

    Scaling Analysis of Fluctuating Strength Function

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    We propose a new method to analyze fluctuations in the strength function phenomena in highly excited nuclei. Extending the method of multifractal analysis to the cases where the strength fluctuations do not obey power scaling laws, we introduce a new measure of fluctuation, called the local scaling dimension, which characterizes scaling behavior of the strength fluctuation as a function of energy bin width subdividing the strength function. We discuss properties of the new measure by applying it to a model system which simulates the doorway damping mechanism of giant resonances. It is found that the local scaling dimension characterizes well fluctuations and their energy scales of fine structures in the strength function associated with the damped collective motions.Comment: 22 pages with 9 figures; submitted to Phys. Rev.

    Fine structure of the isoscalar giant quadrupole resonance in 40Ca due to Landau damping?

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    The fragmentation of the Isoscalar Giant Quadrupole Resonance (ISGQR) in 40Ca has been investigated in high energy-resolution experiments using proton inelastic scattering at E_p = 200 MeV. Fine structure is observed in the region of the ISGQR and its characteristic energy scales are extracted from the experimental data by means of a wavelet analysis. The experimental scales are well described by Random Phase Approximation (RPA) and second-RPA calculations with an effective interaction derived from a realistic nucleon-nucleon interaction by the Unitary Correlation Operator Method (UCOM). In these results characteristic scales are already present at the mean-field level pointing to their origination in Landau damping, in contrast to the findings in heavier nuclei and also to SRPA calculations for 40Ca based on phenomenological effective interactions, where fine structure is explained by the coupling to two-particle two-hole (2p-2h) states.Comment: Phys. Lett. B, in pres

    Oxidation of an Oligonucleotide-Bound Ce-III/Multiphosphonate Complex for Site-Selective DNA Scission

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    Oligodeoxyribonucleotide conjugates of ethylenediamine-N,N,N',N'-tetrakis(methylenephosphonic acid) (EDTP) have been used to place a Ce-III/EDTP complex in close proximity to predetermined phosphodiester linkages of a complementary target oligonucleotide. In the presence of atmospheric oxygen, the Ce-III is oxidized into Ce-IV which, in turn, efficiently cleaves the target phosphodiester linkage. No cleavage occurs at the other single-stranded regions, which suggests that the catalytic Ce species is strictly localized next to the target phosphodiester linkage. No decrease in the reaction rate is observed upon introduction of scavengers for hydroxyl radicals (such as DMSO or MeOH) or singlet oxygen (such as NaN3) to the system; this indicates that the reaction proceeds via a hydrolytic pathway. Any significant contribution by an oxidative pathway is further ruled out by the observation that nucleosides remain intact after incubation with Ce-IV/EDTP complex for extended periods

    New features on the expression and trafficking of mglur1 splice variants exposed by two novel mutant mouse lines

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    Metabotropic glutamate receptors (mGluRs) couple to G-proteins to modulate slow synaptic transmission via intracellular second messengers. The first cloned mGluR, mGluR1, regulates motor coordination, synaptic plasticity and synapse elimination. mGluR1 undergoes alternative splicing giving rise to four translated variants that differ in their intracellular C-terminal domains. Our current knowledge about mGluR1 relates almost entirely to the long mGluR1α isoform, whereas little is known about the other shorter variants. To study the expression of mGluR1γ, we have generated by means of the CRISPR/Cas9 system a new knock-in (KI) mouse line in which the C-terminus of this variant carries two short tags. Using this mouse line, we could establish that mGluR1γ is either untranslated or in amounts that are undetectable in the mouse cerebellum, indicating that only mGluR1α and mGluR1β are present and active at cerebellar synapses. The trafficking and function of mGluR1 appear strongly influenced by adaptor proteins such as long Homers that bind to the C-terminus of mGluR1α. We generated a second transgenic (Tg) mouse line in which mGluR1α carries a point mutation in its Homer binding domain and studied whether disruption of this interaction influenced mGluR1 subcellular localization at cerebellar parallel fiber (PF)-Purkinje cell (PC) synapses by means of the freeze-fracture replica immunolabeling technique. These Tg animals did not show any overt behavioral phenotype, and despite the typical mGluR1 perisynaptic distribution was not significantly changed, we observed a higher probability of intrasynaptic diffusion suggesting that long Homers regulate the lateral mobility of mGluR1. We extended our ultrastructural analysis to other mouse lines in which only one mGluR1 variant was reintroduced in PC of mGluR1-knock out (KO) mice. This work revealed that mGluR1α preferentially accumulates closer to the edge of the postsynaptic density (PSD), whereas mGluR1β has a less pronounced perijunctional distribution and, in the absence of mGluR1α, its trafficking to the plasma membrane is impaired with an accumulation in intracellular organelles. In conclusion, our study sets several firm points on largely disputed matters, namely expression of mGluR1γ and role of the C-terminal domain of mGluR1 splice variants on their perisynaptic clustering

    Design of beam optics for the Future Circular Collider e+e- -collider rings

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    A beam optics scheme has been designed for the Future Circular Collider-e+e- (FCC-ee). The main characteristics of the design are: beam energy 45 to 175 GeV, 100 km circumference with two interaction points (IPs) per ring, horizontal crossing angle of 30 mrad at the IP and the crab-waist scheme [1] with local chromaticity correction. The crab-waist scheme is implemented within the local chromaticity correction system without additional sextupoles, by reducing the strength of one of the two sextupoles for vertical chromatic correction at each side of the IP. So-called "tapering" of the magnets is applied, which scales all fields of the magnets according to the local beam energy to compensate for the effect of synchrotron radiation (SR) loss along the ring. An asymmetric layout near the interaction region reduces the critical energy of SR photons on the incoming side of the IP to values below 100 keV, while matching the geometry to the beam line of the FCC proton collider (FCC-hh) [2] as closely as possible. Sufficient transverse/longitudinal dynamic aperture (DA) has been obtained, including major dynamical effects, to assure an adequate beam lifetime in the presence of beamstrahlung and top-up injection. In particular, a momentum acceptance larger than +/-2% has been obtained, which is better than the momentum acceptance of typical collider rings by about a factor of 2. The effects of the detector solenoids including their compensation elements are taken into account as well as synchrotron radiation in all magnets. The optics presented in this paper is a step toward a full conceptual design for the collider. A number of issues have been identified for further study
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