5,808 research outputs found
Biospheric context of Siberian development
Recent publications on human appropriation of Net Primary Production (NPP) raise the question of how much of the biosphere’s productivity we can appropriate in a sustainable way. This article brings the issue into the context of Siberian development. In contrast to many other regions of the world, the population density in Siberia is still very low as compared to the NPP supplied by regional ecosystems. Hence, it is not too late to raise the question on how much of the NPP supplied by Siberian ecosystems we can appropriate in a sustainable way
Biospheric context of Siberian development
Productivity of ecosystems surrounding a city is important for supporting its activities in a sustainable way. The total terrestrial net primary production (NPP) shows biosphere potential to supply primary food energy source for all non-autotrophic species including humans. Humans appropriate approximately 20% of NPP, in average. Even in the relatively well-populated regions of Siberia, NPP per capita exceeds the average level by several times suggesting the window of opportunity for achieving sustainable development. (3 pages, 1086 words, 2 maps)

SiO Maser Survey towards off-plane O-rich AGBs around the orbital plane of the Sagittarius Stellar Stream
We conducted an SiO maser survey towards 221 O-rich AGB stars with the aim of
identifying maser emission associated with the Sagittarius stellar stream. In
this survey, maser emission was detected in 44 targets, of which 35 were new
detections. All of these masers are within 5 kpc of the Sun. We also compiled a
Galactic SiO maser catalogue including ~2300 SiO masers from the literature.
The distribution of these SiO masers give a scale height of 0.40 kpc, while 42
sources deviate from the Galactic plane by more than 1.2 kpc, half of which
were found in this survey. Regarding SiO masers in the disc, we found both the
rotational speeds and the velocity dispersions vary with the Galactic plane
distance. Assuming Galactic rotational speed 0 = 240 km/s , we derived
the velocity lags are 15 km/s and 55 km/s for disc and off-plane SiO masers
respectively. Moreover, we identified three groups with significant peculiar
motions (with 70% confidence). The most significant group is in the thick disc
that might trace stream/peculiar motion of the Perseus arm. The other two
groups are mainly made up of off-plane sources. The northern and southern
off-plane sources were found to be moving at ~33 km/s and 54 km/s away from the
Galactic plane, respectively. Causes of these peculiar motions are still
unclear. For the two off-plane groups, we suspect they are thick disc stars
whose kinematics affected by the Sgr stellar stream or very old Sgr stream
debris.Comment: 27 pages, 17 figures, MNRAS accepted 2017 September 1
Antimatter from supersymmetric dark matter
We propose low-energy antideuterons in cosmic rays as a new possible
signature for indirect detection of supersymmetric dark matter.
Since the energy spectrum of the antiproton secondary component is still
spoilt by considerable theoretical uncertainties, looking for low-energy
antideuterons seems a plausible alternative.
We apply our calculation to the AMS experiment, when mounted on the
International Spatial Station. If a few low-energy antideuterons will be
discovered by AMS, this should be seriously taken as a clue for the existence
of relic, massive neutralinos in the dark halo of our Galaxy.Comment: 8 pages, 8 figures, Talk presented at the 4th International Symposium
On Sources And Detection Of Dark Matter In The Universe (DM 2000), Marina del
Rey, California, 23-25 Feb. 200
Period-Luminosity Relation for Type II Cepheids
We have estimated JHKs magnitudes corrected to mean intensity for LMC type II
Cepheids found in the OGLE-III survey. Period-luminosity relations (PLRs) are
derived in JHKs as well as in a reddening-free VI parameter. The BL Her stars
(P<4d) and the W Vir stars (P=4 to 20d) are co-linear in these PLRs. The slopes
of the infrared relations agree with those found previously for type II
Cepheids in globular clusters within the uncertainties. Using the pulsation
parallaxes of V553 Cen and SW Tau, the data lead to an LMC modulus of
18.46+-0.10 mag, uncorrected for any metallicity effects. We have now
established the PLR of type II Cepheids as a distance indicator by confirming
that (almost) the same PLR satisfies the distributions in the PL diagram of
type II Cepheids in (at least) two different systems, i.e. the LMC and Galactic
globular clusters, and by calibrating the zero point of the PLR. RV Tau stars
in the LMC, as a group, are not co-linear with the shorter-period type II
Cepheids in the infrared PLRs in marked contrast to such stars in globular
clusters. We note differences in period distribution and infrared colors for RV
Tau stars in the LMC, globular clusters and Galactic field. We also compare the
PLR of type II Cepheids with that of classical Cepheids.Comment: To appear in the proceedings for the conference "Stellar Pulsation:
Challenges for Theory and Observations" held in Santa Fe, US
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