26 research outputs found
Log-convexity and log-concavity of hypergeometric-like functions
We find sufficient conditions for log-convexity and log-concavity for the
functions of the forms ,
and . The most
useful examples of such functions are generalized hypergeometric functions. In
particular, we generalize the Tur\'{a}n inequality for the confluent
hypergeometric function recently proved by Barnard, Gordy and Richards and
log-convexity results for the same function recently proved by Baricz. Besides,
we establish a reverse inequality which complements naturally the inequality of
Barnard, Gordy and Richards. Similar results are established for the Gauss and
the generalized hypergeometric functions. A conjecture about monotonicity of a
quotient of products of confluent hypergeometric functions is made.Comment: 13 pages, no figure
Planck scale effects in neutrino physics
We study the phenomenology and cosmology of the Majoron (flavon) models of
three active and one inert neutrino paying special attention to the possible
(almost) conserved generalization of the Zeldovich-Konopinski-Mahmoud lepton
charge. Using Planck scale physics effects which provide the breaking of the
lepton charge, we show how in this picture one can incorporate the solutions to
some of the central issues in neutrino physics such as the solar and
atmospheric neutrino puzzles, dark matter and a 17 keV neutrino. These
gravitational effects induce tiny Majorana mass terms for neutrinos and
considerable masses for flavons. The cosmological demand for the sufficiently
fast decay of flavons implies a lower limit on the electron neutrino mass in
the range of 0.1-1 eV.Comment: 24 pages, 1 figure (not included but available upon request), LaTex,
IC/92/196, SISSA-140/92/EP, LMU-09/9
sPlotOpen â An environmentally balanced, openâaccess, global dataset of vegetation plots
Assessing biodiversity status and trends in plant communities is critical for understanding, quantifying and predicting the effects of global change on ecosystems. Vegetation plots record the occurrence or abundance of all plant species co-occurring within delimited local areas. This allows species absences to be inferred, information seldom provided by existing global plant datasets. Although many vegetation plots have been recorded, most are not available to the global research community. A recent initiative, called âsPlotâ, compiled the first global vegetation plot database, and continues to grow and curate it. The sPlot database, however, is extremely unbalanced spatially and environmentally, and is not open-access. Here, we address both these issues by (a) resampling the vegetation plots using several environmental variables as sampling strata and (b) securing permission from data holders of 105 local-to-regional datasets to openly release data. We thus present sPlotOpen, the largest open-access dataset of vegetation plots ever released. sPlotOpen can be used to explore global diversity at the plant community level, as ground truth data in remote sensing applications, or as a baseline for biodiversity monitoring