155 research outputs found
Proto-Indo-European lexicon and the next generation of smart etymological dictionaries : The technical issues of the preparation
Peer reviewe
Wood-decaying Basidiomycetes Associated with Dwarf Siberian Pine in Northeast Siberia and the Kamchatka Peninsula
A survey of the biodiversity of wood-decaying Basidiomycetes associated with Pinus pumila (the dwarf Siberian pine), a highly characteristic woody plant of Northeast Siberia and the Kamchatka Peninsula, is presented for the first time. Thirty-two species of wood-decaying Basidiomycetes were recorded in the area for this tree, ofwhich twenty-seven were described the first time: 19 species in the Magadan region and 9 in the Kamchatka Peninsula. Communities of wood-decaying fungi associated with P. pumila have low biodiversity and consist of 16 species in the Kamchatka Peninsula and 21 species in the Magadan region, with only 5 of them being common to both areas. All fungi associated with dwarf Siberian pine belong to widespread species and are not specialized to this tree: they are extremely low in numbers and their composition strongly varies in different habitats. This shows that this tree does not have its own specialized and stable complex of wood-decaying Basidiomycetes.
Keywords: biodiversity, Czekanowski-Sørensen index, host-specializatio
Mapping the three-body system - decay time and reversibility
In this paper we carry out a quantitative analysis of the three-body systems
and map them as a function of decaying time and intial conguration, look at
this problem as an example of a simple deterministic system, and ask to what
extent the orbits are really predictable. We have investigated the behavior of
about 200 000 general Newtonian three body systems using the simplest initial
conditions. Within our resolution these cover all the possible states where the
objects are initially at rest and have no angular momentum. We have determined
the decay time-scales of the triple systems and show that the distribution of
this parameter is fractal in appearance. Some areas that appear stable on large
scales exhibit very narrow strips of instability and the overall pattern,
dominated by resonances, reminds us of a traditional Maasai warrior shield.
Also an attempt is made to recover the original starting conguration of the
three bodies by backward integration. We find there are instances where the
evolution to the future and to the past lead to different orbits, in spite of
time symmetric initial conditions. This implies that even in simple
deterministic systems there exists an Arrow of Time.Comment: 8 pages, 9 figures. Accepted for publication in MNRAS. Includes
low-resolution figures. High-resolution figures are available as PNG
Микобиота афиллофоровых грибов Енисейского меридиана (Средняя Сибирь ): первые результаты исследований в широтном градиенте
Многолетние исследования афиллофоровых грибов Средней Сибири впервые позволили составить единый список видов региона, ранжированный их в широтно-зональном градиенте. На данный момент в Средней Сибири выявлено 557 видов афиллофоровых грибов. Наиболее хорошо изучен список тундровых, лесотундровых, средне-, южно- и подтаежных экосистем, тогда как северотаежные и пустынные — требуют дополнительных исследований. Несомненно, данный результат не итоговый, а будет корректироваться вместе с поступающими новыми данными
ROPS: A New Search for Habitable Earths in the Southern Sky
We present the first results from our Red Optical Planet Survey (ROPS) to
search for low mass planets orbiting late type dwarfs (M5.5V - M9V) in their
habitable zones (HZ). Our observations, with the red arm of the MIKE
spectrograph (0.5 - 0.9 microns) at the 6.5 m Magellan Clay telescope at Las
Campanas Observatory indicate that >= 92 per cent of the flux lies beyond 0.7
microns. We use a novel approach that is essentially a hybrid of the
simultaneous iodine and ThAr methods for determining precision radial
velocities. We apply least squares deconvolution to obtain a single high S/N
ratio stellar line for each spectrum and cross correlate against the
simultaneously observed telluric line profile, which we derive in the same way.
Utilising the 0.62 - 0.90 micron region, we have achieved an r.m.s. precision
of 10 m/s for an M5.5V spectral type star with spectral S/N ~160 on 5 minute
timescales. By M8V spectral type, a precision of ~30 m/s at S/N = 25 is
suggested, although more observations are needed. An assessment of our errors
and scatter in the radial velocity points hints at the presence of stellar
radial velocity variations. Of our sample of 7 stars, 2 show radial velocity
signals at 6-sigma and 10-sigma of the cross correlation uncertainties. If the
signals are planetary in origin, our findings are consistent with estimates of
Neptune mass planets that predict a frequency of 13 - 27 per cent for early M
dwarfs.Our current analysis indicates the we can achieve a sensitivity that is
equivalent to the amplitude induced by a 6 M_Earth planet orbiting in the
habitable zone. Based on simulations, we estimate that <10 M_Earth habitable
zone planets will be detected in a new stellar mass regime, with <=20 epochs of
observations.Comment: MNRAS accepted: 14 pages, 8 figures, 3 table
T-cell subpopulations αβ and γδ in cord blood of very preterm infants : The influence of intrauterine infection
Open Access: This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are creditedPreterm infants are very susceptible to infections. Immune response mechanisms in this group of patients and factors that influence cord blood mononuclear cell populations remain poorly understood and are considered insufficient. However, competent immune functions of the cord blood mononuclear cells are also described. The aim of this work was to evaluate the T-cell population (CD3+) with its subpopulations bearing T-cell receptor (TCR) αβ or TCR γδ in the cord blood of preterm infants born before 32 weeks of gestation by mothers with or without an intrauterine infection. Being a pilot study, it also aimed at feasibility check and assessment of an expected effect size. The cord blood samples of 46 infants age were subjected to direct immunofluorescent staining with monoclonal antibodies and then analyzed by flow cytometry. The percentage of CD3+ cells in neonates born by mothers with diagnosis of intrauterine infection was significantly lower than in neonates born by mothers without infection (p = 0.005; Mann-Whitney U test). The number of cells did not differ between groups. Infection present in the mother did not have an influence on the TCR αβ or TCR γδ subpopulations. Our study contributes to a better understanding of preterm infants' immune mechanisms, and sets the stage for further investigations.Peer reviewedFinal Published versio
Wideband 67-116 GHz cryogenic receiver development for ALMA Band 2
The Atacama Large Millimeter/sub-millimeter Array (ALMA) is already
revolutionising our understanding of the Universe. However, ALMA is not yet
equipped with all of its originally planned receiver bands, which will allow it
to observe over the full range of frequencies from 35-950 GHz accessible
through the Earth's atmosphere. In particular Band 2 (67-90 GHz) has not yet
been approved for construction. Recent technological developments in cryogenic
monolithic microwave integrated circuit (MMIC) high electron mobility
transistor (HEMT) amplifier and orthomode transducer (OMT) design provide an
opportunity to extend the originally planned on-sky bandwidth, combining ALMA
Bands 2 and 3 into one receiver cartridge covering 67-116 GHz.
The IF band definition for the ALMA project took place two decades ago, when
8 GHz of on-sky bandwidth per polarisation channel was an ambitious goal. The
new receiver design we present here allows the opportunity to expand ALMA's
wideband capabilities, anticipating future upgrades across the entire
observatory. Expanding ALMA's instantaneous bandwidth is a high priority, and
provides a number of observational advantages, including lower noise in
continuum observations, the ability to probe larger portions of an astronomical
spectrum for, e.g., widely spaced molecular transitions, and the ability to
scan efficiently in frequency space to perform surveys where the redshift or
chemical complexity of the object is not known a priori. Wider IF bandwidth
also reduces uncertainties in calibration and continuum subtraction that might
otherwise compromise science objectives.
Here we provide an overview of the component development and overall design
for this wideband 67-116 GHz cryogenic receiver cartridge, designed to operate
from the Band 2 receiver cartridge slot in the current ALMA front end receiver
cryostat.Comment: 8 pages, proceedings from the 8th ESA Workshop on Millimetre-Wave
Technology and Applications
(https://atpi.eventsair.com/QuickEventWebsitePortal/millimetre-wave/mm-wave
Pre-natal and post-natal exposure to respiratory infection and atopic diseases development: a historical cohort study
BACKGROUND: According to the hygiene hypothesis, infections in early life protect from allergic diseases. However, in earlier studies surrogate measures of infection rather than clinical infections were associated with decreased frequencies of atopic diseases. Exposure to infection indicating sub-clinical infection rather than clinical infection might protect from atopic diseases. Objective: to investigate whether exposure to acute respiratory infections within pregnancy and the first year of life is associated with atopic conditions at age 5–14 years and to explore when within pregnancy and the first year of life this exposure is most likely to be protective. METHODS: Historical cohort study: Population level data on acute respiratory infections from the routine reporting system of the former German Democratic Republic were linked with individual data from consecutive surveys on atopic diseases in the same region (n = 4672). Statistical analyses included multivariate logistic regression analysis and polynomial distributed lag models. RESULTS: High exposure to acute respiratory infection between pregnancy and age one year was associated with overall reduced odds of asthma, eczema, hay fever, atopic sensitization and total IgE. Exposure in the first 9 months of life showed the most pronounced effect. Adjusted odds ratio's for asthma, hay fever, inhalant sensitization and total IgE were statistical significantly reduced up to around half. CONCLUSION: Exposure to respiratory infection (most likely indicating sub-clinical infection) within pregnancy and the first year of life may be protective in atopic diseases development. The post-natal period thereby seems to be particularly important
- …