235 research outputs found

    Differential photosynthetic adaptation between size-classes of Spruce and Fir juveniles help to explain the co-existence of the two species.

    Get PDF
    Background/Question/Methods 
_Abies sachalinensis_ (Sakhalin Fir) and _Picea glehnii_ (Glehn’s Spruce) are major components of the sub-boreal forests of Hokkaido, Japan. Similar Spruce-Fir forests can be found in many other places in the northern hemisphere and will probably be impacted by global warming. Therefore, detailed knowledge of these species’ physiology and life-history strategies at different growth stages is important to understand present communities and to support reliable prediction of possible consequences of global climate change. 
Accordingly, the objective of this study was to establish relations between community dynamics, life-history strategies and photosynthetic adaptation of these species, on different developmental stages. 
The study is taking place on a sub-boreal forest plot in north Japan (N 44º 19’, E 142º 15’). Twenty shade-growing individuals of both species were divided into two height classes: seedlings, if height < 50cm; and saplings, if height > 100cm. The canopy coverage over each individual was assessed by analyzing hemispherical photography and average light incidence. Leaf pigments are being analyzed by chromatography. Light response curves and chlorophyll fluorescence are being measured seasonally, except in winter. Results are analyzed through General Linear Models. The study period was from spring 2009 to summer 2010. 
Results/Conclusions 
Results show an inversion of the photosynthetic adaptation between seedlings and saplings, and also between species. _Picea_ seedlings and _Abies_ saplings have greater total chlorophyll content and higher photosynthetic rates than _Picea_ saplings and _Abies_ seedlings. As a consequence, the superior competitor between similar sized individuals of both species appears to change between size-classes, with _Abies_ presenting higher photosynthetic rates at the sapling class and _Picea_ at the seedling class. Nevertheless, no significant growth has been observed in any of the groups until now. Results also disagree with some of the previously reported photosynthetic characteristics of these species, with _Picea_ seedlings displaying more traits usually associated with shade adaptation than _Abies_ seedlings.
&#xa

    FUNDAMENTAL NUMERICAL ANALYSIS OF INSOLATION OF THE HUMAN BODY

    Get PDF
    ABSTRACT Uneven thermal environments often result from insolation or radiation in outdoor spaces and half outdoor spaces such as arcades and under open membrane roofs. Similar environments are observed in the perimeter spaces of office buildings in winter during the daytime. To estimate thermal environments in such spaces, detailed consideration must be given to the effects of both insolation and long-wavelength radiation on each part of the human body. This study conducted fundamental analysis of the calculations of insolation of a human body. The incident insolation to each part of a human body was evaluated. The results are reported herein

    Neutrino self-interaction and MSW effects on the supernova neutrino-process

    Full text link
    We calculate the abundances of 7^{7}Li, 11^{11}B, 92^{92}Nb, 98^{98}Tc, 138^{138}La, and 180^{180}Ta produced by neutrino (ν)(\nu) induced reactions in a core-collapse supernova explosion. We consider the modification by ν\nu self-interaction (ν\nu-SI) near the neutrinosphere and the Mikheyev-Smirnov-Wolfenstein effect in outer layers for time-dependent neutrino energy spectra. Abundances of 7^{7}Li and heavy isotopes 92^{92}Nb, 98^{98}Tc and 138^{138}La are reduced by a factor of 1.5-2.0 by the ν\nu-SI. In contrast, 11^{11}B is relatively insensitive to the ν\nu-SI. We find that the abundance ratio of heavy to light nucleus, 138^{138}La/11^{11}B, is sensitive to the neutrino mass hierarchy, and the normal mass hierarchy is more likely to be consistent with the solar abundances

    Comprehensive Analyses of the Neutrino-Process in the Core-collapsing Supernova

    Full text link
    We investigate the neutrino flavor change effects due to neutrino self-interaction, shock wave propagation as well as matter effect on the neutrino process of the core-collapsing supernova. For the hydrodynamics, we use two models: a simple thermal bomb model and a specified hydrodynamic model for SN1987A. As a pre-supernova model, we take an updated model adjusted to explain the SN1987A employing recent development of the (n,γ)(n,\gamma) reaction rates for nuclei near the stability line (A100)(A \sim 100). As for the neutrino luminosity, we adopt two different models: equivalent neutrino luminosity and non-equivalent luminosity models. The latter is taken from the synthetic analyses of the CCSN simulation data which involved quantitatively the results obtained by various neutrino transport models. Relevant neutrino-induced reaction rates are calculated by a shell model for light nuclei and a quasi-particle random phase approximation model for heavy nuclei. For each model, we present abundances of the light nuclei (7^7Li, 7^7Be, 11^{11}B and 11^{11}C) and heavy nuclei (92^{92}Nb, 98^{98}Tc, 138^{138}La and 180^{180}Ta) produced by the neutrino-process. The light nuclei abundances turn out to be sensitive to the Mikheyev-Smirnov-Wolfenstein region around ONeMg region while the heavy nuclei are mainly produced prior to the MSW region. Through the detailed analyses of the numerical abundances, we find that neutrino self-interaction becomes a key ingredient in addition to the MSW effect for understanding the neutrino process and the relevant nuclear abundances. However, the whole results are shown to depend on the adopted neutrino luminosity scheme. Detailed evaluations of the nuclear abundances for the two possible neutrino mass hierarchies are performed with the comparison to the available meteorite analyses data. The normal mass hierarchy is shown to be more compatible with the meteoritic data

    Sideward Peak of Intermediate Mass Fragments in High Energy Proton Induced Reactions

    Get PDF
    Intermediate mass fragment (IMF) formation in the 12 GeV proton induced reaction on Au target is analyzed by using a combined framework of a transport model (JAM/MF) and a newly developed non-equilibrium percolation (NEP) model. In this model, we can well reproduce the mass distribution of fragments. In addition, the sideward peaked angular distribution would emerge under the condition that the fragment formation time is very short, around 20 fm/c. Within this short time period, the un-heated part of the residual nucleus is kept to have doughnut shape, then the Coulomb repulsion from this shape strengthens the sideward peak of IMF.Comment: 22 pages, Latex, 6 embedded PS figure
    corecore