286 research outputs found
Slit Observations and Empirical Calculations for HII Regions
When analysing HII regions, a possible source of systematic error on
empirically derived physical quantities is the limited size of the slit used
for the observations. A grid of photoionization models was built through the
Aangaba code varying the ionizing radiation spectrum emitted by a stellar
cluster, as well as the gas abundance. The calculated line surface brightness
was then used to simulate slit observations and to derive empirical parameters
using the usual methods described in the literature. Depending on the fraction
of the object covered by the slit, the parameters can be different from those
obtained from observations of the whole object, an effect that is mainly
dependent on the age of the ionizing stellar cluster. The low-ionization
forbidden lines are more sensitive to the size of the area covered by the slit
than the high-ionization forbidden lines or recombination lines. Regarding the
temperature indicator T[OIII], the slit effects are small since this
temperature is derived from [OIII] lines. On the other hand, for the abundance
indicator R23, which depends also on the [OII] line, the slit effect is
slightly higher. Therefore, the systematic error due to slit observations on
the O abundance is low, being usually less than 10%, except for HII regions
powered by stellar clusters with a relative low number of ionizing photons
between 13.6 and 54.4 eV, which create a smaller O++ emitting volume. In this
case, the systematic error on the empirical O abundance deduced from slit
observations is more than 10% when the covered area is less than 50%.Comment: To be published in MNRAS, accepted in 09/09/2005, 17 pages and 6
figure
Mushrooms Red Book of Ukraine in Culture. 1. Patterns of Growth Hericium coralloides
ĐĐ° ŃĐ”ŃĐžŃĐŸŃŃŃ ĐĐР«ĐŃŃŃĐ»ŃŃĐžĐœĐ°Â» ĐČĐžŃĐČĐ»Đ”ĐœĐŸ лОŃĐ” ŃŃĐž Đ»ĐŸĐșĐ°Đ»ŃŃĐ”ŃĐž Hericium coralloides â ĐłŃОба, Đ·Đ°ĐœĐ”ŃĐ”ĐœĐŸĐłĐŸ
ĐŽĐŸ ЧДŃĐČĐŸĐœĐŸŃ ĐșĐœĐžĐłĐž ĐŁĐșŃĐ°ŃĐœĐž. ĐŁ ŃДзŃĐ»ŃŃĐ°ŃŃ ĐżŃĐŸĐČĐ”ĐŽĐ”ĐœĐžŃ
ĐŽĐŸŃĐ»ŃĐŽĐ¶Đ”ĐœŃ ĐČОЎŃĐ»Đ”ĐœĐŸ ĐČ ŃĐžŃŃŃ ĐșŃĐ»ŃŃŃŃŃ Đ°Đ±ĐŸŃĐžĐłĐ”ĐœĐœĐžĐč ŃŃĐ°ĐŒ Đ01.
ĐŻĐș ĐŽĐ»Ń ĐČОЎŃĐ»Đ”ĐœĐœŃ, ŃĐ°Đș Ń ĐŽĐ»Ń ĐżŃĐŽŃŃĐžĐŒĐșĐž ŃĐ° забДзпДŃĐ”ĐœĐœŃ Đ¶ĐžŃŃŃĐ·ĐŽĐ°ŃĐœĐŸŃŃŃ ĐłŃОба ĐČ ĐșŃĐ»ŃŃŃŃŃ ĐșĐ°ŃŃĐŸĐżĐ”Đ»ŃĐœĐŸ-глŃĐșĐŸĐ·ĐœĐžĐč
Đ°ĐłĐ°Ń ĐČĐžŃĐČĐžĐČŃŃ ĐŸĐżŃĐžĐŒĐ°Đ»ŃĐœĐžĐŒ ŃĐ”ŃДЎ Đ°ĐżŃĐŸĐ±ĐŸĐČĐ°ĐœĐžŃ
ŃĐ”ŃĐ”ĐŽĐŸĐČĐžŃ. ĐĐœĐŽĐžĐČŃĐŽŃĐ°Đ»ŃĐœŃ ĐŸŃĐŸĐ±Đ»ĐžĐČĐŸŃŃŃ ŃĐŸŃŃŃ H. coralloides Đ01
ĐČĐșĐ°Đ·ŃŃŃŃ ĐœĐ° ĐČŃĐ·ŃĐșŃ ŃŃĐŸŃŃŃĐœŃ ĐŒĐŸĐ¶Đ»ĐžĐČĐŸŃŃŃ ŃŃĐŸĐłĐŸ ŃŃĐ°ĐŒŃ ĐżŃĐž ĐżĐŸĐČĐ”ŃŃ
ĐœĐ”ĐČĐŸĐŒŃ ĐșŃĐ»ŃŃĐžĐČŃĐČĐ°ĐœĐœŃ, ĐŸŃĐșŃĐ»ŃĐșĐž Đ· ĐżâŃŃĐž Đ°ĐżŃĐŸĐ±ĐŸĐČĐ°ĐœĐžŃ
ŃĐ”ŃĐ”ĐŽĐŸĐČĐžŃ ĐżŃОЎаŃĐœĐžĐŒĐž ĐŽĐ»Ń ŃĐŸŃŃŃ ĐČĐžŃĐČОлОŃŃ Đ»ĐžŃĐ” ĐŽĐČĐ°. ĐŠĐ”Đč ŃŃĐ°ĐŒ ĐłŃОба ĐČĐČажаŃĐŒĐŸ пДŃŃпДĐșŃĐžĐČĐœĐžĐŒ ĐŽĐ»Ń
ĐČĐžĐșĐŸŃĐžŃŃĐ°ĐœĐœŃ ŃĐș ŃĐœĐŸĐșŃĐ»ŃĐœŃĐ° ĐČŃĐŽĐżĐŸĐČŃĐŽĐœĐžŃ
ŃŃбŃŃŃĐ°ŃŃĐČ Ń ĐżŃĐžŃĐŸĐŽĐœĐŸĐŒŃ ŃĐ”ŃĐ”ĐŽĐŸĐČĐžŃŃ, ĐŸŃĐșŃĐ»ŃĐșĐž ĐŽĐ»Ń ĐœŃĐŸĐłĐŸ Ń
Đ°ŃĐ°ĐșŃĐ”ŃĐœŃ
ĐČĐžŃĐŸĐșŃ ĐżĐŸĐșĐ°Đ·ĐœĐžĐșĐž ŃĐ°ĐŽŃĐ°Đ»ŃĐœĐŸĐłĐŸ ŃĐŸŃŃŃ, ĐșĐŸŃĐŸŃĐșĐžĐč пДŃŃĐŸĐŽ log-ŃĐ°Đ·Đž ŃĐ° ŃŃĐČĐŸŃĐ”ĐœĐœŃ ĐČ ŃĐžŃŃŃĐč ĐșŃĐ»ŃŃŃŃŃ ŃŃĐ°ĐŽŃŃ ŃĐ”Đ»Đ”ĐŸĐŒĐŸŃŃĐž. The national park «Hutsulshchyna» found only three localities of
Hericium coralloides â mushroom Red Book of Ukraine. The result of the research was to obtain in a pure culture of
the native strain K01. As for the release, and to support and ensure the viability of the fungus in culture potato -
glucose agar was the best among the tested environments. Individual features of the growth of H. coralloides K01
indicate the narrow trophic features of this strain at cultivation because from five tested media suitable for growth were
only two. This strain K01 H. coralloides may be considered promising for use as an inoculant respective substrates in
the environment , because it is characterized by high rates of radial growth , a short period of log- phase and ability to
form stage teleomorfy in pure culture.Đ ĐŸĐ±ĐŸŃŃ ĐČĐžĐșĐŸĐœĐ°ĐœĐŸ Ń ĐĐР«ĐŃŃŃĐ»ŃŃĐžĐœĐ°Â»,
ĐĐĐŠ «ĐĐœŃŃĐžŃŃŃ Đ±ŃĐŸĐ»ĐŸĐłŃŃ» ĐĐĐŁ ŃĐŒ. Đą. КДĐČŃĐ”ĐœĐș
Evaluation of the LSA-SAF gross primary production product derived from SEVIRI/MSG data (MGPP)
The objective of this study is to describe a completely new 10-day gross primary production (GPP) product (MGPP LSA-411) based on data from the geostationary SEVIRI/MSG satellite within the LSA SAF (Land Surface Analysis SAF) as part of the SAF (Satellite Application Facility) network of EUMETSAT. The methodology relies on the Monteith approach. It considers that GPP is proportional to the absorbed photosynthetically active radiation APAR and the proportionality factor is known as the light use efficiency Δ. A parameterization of this factor is proposed as the product of a Δmax, corresponding to the canopy functioning under optimal conditions, and a coefficient quantifying the reduction of photosynthesis as a consequence of water stress. A three years data record (2015â2017) was used in an assessment against site-level eddy covariance (EC) tower GPP estimates and against other Earth Observation (EO) based GPP products. The site-level comparison indicated that the MGPP product performed better than the other EO based GPP products with 48% of the observations being below the optimal accuracy (absolute error < 1.0 g mâ2 dayâ1) and 75% of these data being below the user requirement threshold (absolute error < 3.0 g mâ2 dayâ1). The largest discrepancies between the MGPP product and the other GPP products were found for forests whereas small differences were observed for the other land cover types. The integration of this GPP product with the ensemble of LSA-SAF MSG products is conducive to meet user needs for a better understanding of ecosystem processes and for improved understanding of anthropogenic impact on ecosystem services.The objective of this study is to describe a completely new 10-day gross primary production (GPP) product (MGPP LSA-411) based on data from the geostationary SEVIRI/MSG satellite within the LSA SAF (Land Surface Analysis SAF) as part of the SAF (Satellite Application Facility) network of EUMETSAT. The methodology relies on the Monteith approach. It considers that GPP is proportional to the absorbed photosynthetically active radiation APAR and the proportionality factor is known as the light use efficiency epsilon. A parameterization of this factor is proposed as the product of a epsilon(max), corresponding to the canopy functioning under optimal conditions, and a coefficient quantifying the reduction of photosynthesis as a consequence of water stress. A three years data record (2015-2017) was used in an assessment against site-level eddy covariance (EC) tower GPP estimates and against other Earth Observation (EO) based GPP products. The site-level comparison indicated that the MGPP product performed better than the other EO based GPP products with 48% of the observations being below the optimal accuracy (absolute error <1.0 g m(-2) day(-1)) and 75% of these data being below the user requirement threshold (absolute error <3.0 g m(-2) day(-1)). The largest discrepancies between the MGPP product and the other GPP products were found for forests whereas small differences were observed for the other land cover types. The integration of this GPP product with the ensemble of LSA-SAF MSG products is conducive to meet user needs for a better understanding of ecosystem processes and for improved understanding of anthropogenic impact on ecosystem services.Peer reviewe
Health promoting potential of herbal teas and tinctures from Artemisia campestris subsp maritima: from traditional remedies to prospective products
This work explored the biotechnological potential of the medicinal halophyte Artemisia campestris subsp. maritima (dune wormwood) as a source of health promoting commodities. For that purpose, infusions, decoctions and tinctures were prepared from roots and aerial-organs and evaluated for in vitro antioxidant, anti-diabetic and tyrosinase-inhibitory potential, and also for polyphenolic and mineral contents and toxicity. The dune wormwood extracts had high polyphenolic content and several phenolics were identified by ultra-high performance liquid chromatography-photodiode array-mass-spectrometry (UHPLC-PDA-MS). The main compounds were quinic, chlorogenic and caffeic acids, coumarin sulfates and dicaffeoylquinic acids; several of the identified phytoconstituents are here firstly reported in this A. campestris subspecies. Results obtained with this plant's extracts point to nutritional applications as mineral supplementary source, safe for human consumption, as suggested by the moderate to low toxicity of the extracts towards mammalian cell lines. The dune wormwood extracts had in general high antioxidant activity and also the capacity to inhibit a-glucosidase and tyrosinase. In summary, dune wormwood extracts are a significant source of polyphenolic and mineral constituents, antioxidants and a-glucosidase and tyrosinase inhibitors, and thus, relevant for different commercial segments like the pharmaceutical, cosmetic and/or food industries.FCT - Foundation for Science and Technology [CCMAR/Multi/04326/2013]; Portuguese National Budget; FCT [IF/00049/2012, SFRH/BD/94407/2013]; Research Foundation - Flanders (FWO) [12M8315N]info:eu-repo/semantics/publishedVersio
Heavy elements in Galactic and Magellanic Cloud HII regions: recombination-line versus forbidden-line abundances
We have obtained deep optical, long-slit spectrophotometry of the Galactic
HII regions M 17, NGC 3576 and of the Magellanic Cloud HII regions 30 Doradus,
LMC N11B and SMC N66, recording the optical recombination lines (ORLs) of CII,
NII and OII. Temperature-insensitive ORL C2+/O2+ and N2+/O2 ratios are obtained
for all nebulae except SMC N66. The ORL C2+/O2+ ratios show remarkable
agreement within each galactic system, while also being in agreement with the
corresponding CEL ratios. For all five nebulae, the O2+/H+ abundance derived
from multiple OII ORLs is found to be higher than the corresponding value
derived from the strong [OIII] 4959, 5007A CELs, by factors of 1.8--2.7 for
four of the nebulae. The LMC N11B nebula exhibits a more extreme discrepancy
factor for the O2+ ion, ~5. Thus these HII regions exhibit ORL/CEL abundance
discrepancy factors that are similar to those previously encountered amongst
planetary nebulae.
Our optical CEL O2+/H+ abundances agree to within 20-30 per cent with
published O2+/H+ abundances that were obtained from observations of infrared
fine-structure lines. Since the low excitation energies of the latter make them
insensitive to variations about typical nebular temperatures, fluctuations in
temperature are ruled out as the cause of the observed ORL/CEL O2+ abundance
discrepancies. We present evidence that the observed OII ORLs from these HII
regions originate from gas of very similar density (<3500 cm-3) to that
emitting the observed heavy-element optical and infrared CELs, ruling out
models that employ high-density ionized inclusions in order to explain the
abundance discrepancy. We consider a scenario whereby much of the heavy-element
ORL emission originates from cold (<=500 K) metal-rich ionized regions.Comment: 24 pages; 9 figures; accepted by Monthly Notices of the Royal
Astronomical Societ
Molecular Hydrogen in the Ionized Region of Planetary Nebulae
This paper presents an analysis of the concentration of the hydrogen molecule
inside the ionized region of planetary nebulae. The equations corresponding to
the ionization and chemical equilibria of H, H+, H-, H2, H2+, and H3+ are
coupled with the equations of ionization and thermal balance for a photoionized
atomic gas. Forty different reactions related to the formation or the
destruction of these species are included. The presence of dust is taken into
account, since grains act as catalysts for the production of H2, as well as
shield the molecules against the stellar ionizing radiation. We analyze the
effect of the stellar ionizing continuum, as well as of the gas and grain
properties on the calculated H2 mass. It is shown that a significant
concentration of H2 can survive inside the ionized region of planetary nebulae,
mostly in the inner region of the recombination zone. The total H2 to total
hydrogen mass ratio inside the ionized region increases with the central star
temperature, and, depending on the PN physical conditions, it can be of the
order of 10^-6 or even higher. The increase of the recombination zone with the
stellar temperature can account for such correlation. This can explain why the
H2 emission is more frequently observed in bipolar planetary nebulae (Gatley's
rule), since this kind of object has typically hotter stars. Applying our
results for the planetary nebula NGC 6720, we obtain an H2 to hydrogen mass
ratio similar to the value obtained from the observed H2 line emission.Comment: 13 pages, 4 figures. Accepted for publication in Ap
Validation of 3D-CMCC Forest Ecosystem Model (v.5.1) against eddy covariance data for 10 European forest sites
This study evaluates the performances of the new version (v.5.1) of 3D-CMCC Forest Ecosystem Model (FEM) in simulating gross primary productivity (GPP), against eddy covariance GPP data for 10 FLUXNET forest sites across Europe. A new carbon allocation module, coupled with new both phenological and autotrophic respiration schemes, was implemented in this new daily version. Model ability in reproducing timing and magnitude of daily and monthly GPP fluctuations is validated at intra-annual and inter-annual scale, including extreme anomalous seasons. With the purpose to test the 3D-CMCC FEM applicability over Europe without a site-related calibration, the model has been deliberately parametrized with a single set of species-specific parametrizations for each forest ecosystem. The model consistently reproduces both in timing and in magnitude daily and monthly GPP variability across all sites, with the exception of the two Mediterranean sites. We find that 3D-CMCC FEM tends to better simulate the timing of inter-annual anomalies than their magnitude within measurements' uncertainty. In six of eight sites where data are available, the model well reproduces the 2003 summer drought event. Finally, for three sites we evaluate whether a more accurate representation of forest structural characteristics (i.e. cohorts, forest layers) and species composition can improve model results. In two of the three sites results reveal that model slightly increases its performances although, statistically speaking, not in a relevant way.Peer reviewe
Molecular chemistry and the missing mass problem in PNe
Detections of molecular lines, mainly from H2$ and CO, reveal molecular
material in planetary nebulae. Observations of a variety of molecules suggest
that the molecular composition in these objects differs from that found in
interstellar clouds or in circumstellar envelopes. The success of the models,
which are mostly devoted to explain molecular densities in specific planetary
nebulae, is still partial, however. The present study aims at identifying the
influence of stellar and nebular properties on the molecular composition of
planetary nebulae by means of chemical models. A comparison of theoretical
results with those derived from the observations may provide clues to the
conditions that favor the presence of a particular molecule. A self-consistent
photoionization numerical code was adapted to simulate cold molecular regions
beyond the ionized zone. The code was used to obtain a grid of models and the
resulting column densities are compared with those inferred from observations.
Our models show that the inclusion of an incident flux of X-rays is required to
explain the molecular composition derived for planetary nebulae. We also obtain
a more accurate relation for the N(CO)/N(H2) ratio in these objects. Molecular
masses obtained by previous works in the literature were then recalculated,
showing that these masses can be underestimated by up to three orders of
magnitude. We conclude that the problem of the missing mass in planetary
nebulae can be solved by a more accurate calculation of the molecular mass.Comment: 12 pages, 11 figure
Customized birth weight for gestational age standards: Perinatal mortality patterns are consistent with separate standards for males and females but not for blacks and whites
BACKGROUND: Some currently available birth weight for gestational age standards are customized but others are not. We carried out a study to provide empirical justification for customizing such standards by sex and for whites and blacks in the United States. METHODS: We studied all male and female singleton live births and stillbirths (22 or more weeks of gestation; 500 g birth weight or over) in the United States in 1997 and 1998. White and black singleton live births and stillbirths were also examined. Qualitative congruence between gestational age-specific growth restriction and perinatal mortality rates was used as the criterion for identifying the preferred standard. RESULTS: The fetuses at risk approach showed that males had higher perinatal mortality rates at all gestational ages compared with females. Gestational age-specific growth restriction rates based on a sex-specific standard were qualitatively consistent with gestational age-specific perinatal mortality rates among males and females. However, growth restriction patterns among males and females based on a unisex standard could not be reconciled with perinatal mortality patterns. Use of a single standard for whites and blacks resulted in gestational age-specific growth restriction rates that were qualitatively congruent with patterns of perinatal mortality, while use of separate race-specific standards led to growth restriction patterns that were incompatible with patterns of perinatal mortality. CONCLUSION: Qualitative congruence between growth restriction and perinatal mortality patterns provides an outcome-based justification for sex-specific birth weight for gestational age standards but not for the available race-specific standards for blacks and whites in the United States
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