887 research outputs found
The Closest Damped Lyman Alpha System
A difficulty of studying damped Lyman alpha systems is that they are distant,
so one knows little about the interstellar medium of the galaxy. Here we report
upon a damped Lyman alpha system in the nearby galaxy NGC 4203, which is so
close (v_helio = 1117 km/s) and bright (B_o = 11.62) that its HI disk has been
mapped. The absorption lines are detected against Ton 1480, which lies only
1.9' (12 h_50 kpc) from the center of NGC 4203. Observations were obtained with
the Faint Object Spectrograph on HST (G270H grating) over the 2222-3277
Angstrom region with 200 km/s resolution. Low ionization lines of Fe, Mn, and
Mg were detected, leading to metallicities of -2.29, -2.4, which
are typical of other damped Lyman alpha systems, but well below the stellar
metallicity of this type of galaxy. Most notably, the velocity of the lines is
1160 +- 10 km/s, which is identical to the HI rotational velocity of 1170 km/s
at that location in NGC 4203, supporting the view that these absorption line
systems can be associated with the rotating disks of galaxies. In addition, the
line widths of the Mg lines give an upper limit to the velocity dispersion of
167 km/s, to the 99% confidence level.Comment: 4 pages LaTeX, including 1 figure and 1 table, uses emulateapj.sty.
Accepted for publication by Astrophysical Journal Letter
Chromosome instability in intergeneric hybrids of Triticum aestivum;× tritordeum (amphiploid Hordeum chilense×Triticum turgidum) with high dosage of Ph1 gene of wheat
In somatic cells of intergencric hybrids Truicum uestirum (mono-isosomic 5BL, 2n=6x=4f)x trinordum 12n = 6x = 42, amphiploid Hordeum clulense x Triticum turgidnm)it was observed that high dosage of the long arm of 5B induced chromosome instability in hybrids 2n=42, in hybrids 2n=41 with only one dose of 5BL from the normal 5B genome of the teteaploed wheat, all cells have consistently 2n=41 chromosomes and no rmal 5B genome of the tetraploid wheat all cells have consistently 2n=41 plant differenttation in plants with 2n=42 which carry three doses of 5BL (one isochromosome 5BL and one 5B chromosome)most of the metaphase cells had 2n=42 chromosomes. However other cells in a reasonable frequency varying from 19% to 40% carried from 2n=6 to 2n=44. and showed marked desturbances in all phases of the cell cycle leading to final failure in plant development. It is suggested that the Ph1 geng of wheat. Located on 5BL regulates chromosome stability in the somatic cells of those hybrids
On the abundance discrepancy problem in HII regions
The origin of the abundance discrepancy is one of the key problems in the
physics of photoionized nebula. In this work, we analize and discuss data for a
sample of Galactic and extragalactic HII regions where this abundance
discrepancy has been determined. We find that the abundance discrepancy factor
(ADF) is fairly constant and of the order of 2 in all the available sample of
HII regions. This is a rather different behaviour than that observed in
planetary nebulae, where the ADF shows a much wider range of values. We do not
find correlations between the ADF and the O/H, O++/H+ ratios, the ionization
degree, Te(High), Te(Low)/ Te(High), FWHM, and the effective temperature of the
main ionizing stars within the observational uncertainties. These results
indicate that whatever mechanism is producing the abundance discrepancy in HII
regions it does not substantially depend on those nebular parameters. On the
contrary, the ADF seems to be slightly dependent on the excitation energy, a
fact that is consistent with the predictions of the classical temperature
fluctuations paradigm. Finally, we obtain that Te values obtained from OII
recombination lines in HII regions are in agreement with those obtained from
collisionally excited line ratios, a behaviour that is again different from
that observed in planetary nebulae. These similar temperature determinations
are in contradiction with the predictions of the model based on the presence of
chemically inhomogeneous clumps but are consistent with the temperature
fluctuations paradigm. We conclude that all the indications suggest that the
physical mechanism responsible of the abundance discrepancy in HII regions and
planetary nebulae are different.Comment: 14 pages, 8 figures, 9 tables. Accepted for publication in the Ap
Gla-rich protein function as an anti-inflammatory agent in monocytes/macrophages: implications for calcification-related chronic inflammatory diseases
Calcification-related chronic inflammatory diseases are multifactorial pathological processes, involving a complex interplay between inflammation and calcification events in a positive feed-back loop driving disease progression. Gla-rich protein (GRP) is a vitamin K dependent protein (VKDP) shown to function as a calcification inhibitor in cardiovascular and articular tissues, and proposed as an anti-inflammatory agent in chondrocytes and synoviocytes, acting as a new crosstalk factor between these two interconnected events in osteoarthritis. However, a possible function of GRP in the immune system has never been studied. Here we focused our investigation in the involvement of GRP in the cell inflammatory response mechanisms, using a combination of freshly isolated human leucocytes and undifferentiated/differentiated THP-1 cell line. Our results demonstrate that VKDPs such as GRP and matrix gla protein (MGP) are synthesized and gamma-carboxylated in the majority of human immune system cells either involved in innate or adaptive immune responses. Stimulation of THP-1 monocytes/macrophages with LPS or hydroxyapatite (HA) up-regulated GRP expression, and treatments with GRP or GRP-coated basic calcium phosphate crystals resulted in the down-regulation of mediators of inflammation and inflammatory cytokines, independently of the protein gamma-carboxylation status. Moreover, overexpression of GRP in THP-1 cells rescued the inflammation induced by LPS and HA, by down-regulation of the proinflammatory cytokines TNF alpha, IL-1 beta and NFkB. Interestingly, GRP was detected at protein and mRNA levels in extracellular vesicles released by macrophages, which may act as vehicles for extracellular trafficking and release. Our data indicate GRP as an endogenous mediator of inflammatory responses acting as an anti-inflammatory agent in monocytes/macrophages. We propose that in a context of chronic inflammation and calcification-related pathologies, GRP might act as a novel molecular mediator linking inflammation and calcification events, with potential therapeutic application.Portuguese Science and Technology Foundation (FCT) [PTDC/SAU-ORG/117266/2010, PTDC/BIM-MEC/1168/2012, UID/Multi/ 04326/2013]; FCT fellowships [SFRH/BPD/70277/2010, SFRH/BD/111824/2015
Genetic diversity of the grapevine (Vitis vinifera L.) cultivars most utilized for wine production in Portugal
Portugal is very rich in grapevine biodiversity but nowadays only a small number of cultivars (13 black and 3 white) with defined enological characteristics are being used. However, there are still 51 cultivars with significant expression in the country which have a great potential to be used in the establishment of new vineyards. Considering the importance of identifying and understanding the genetic relatedness of the main cultivars used for wine making in Portugal, those cultivars were genotyped with the 6 SSRs loci VVMD5, VVMD7, VVMD27, VrZag62, VrZag79 and VVS2 that are recommended by the Office de la Vigne et du Vin for the elaboration of the worldwide database containing the alleles of all the known grapevine cultivars. A total of 49 alleles were detected with an average allele number of 8.17 per locus. The SSR profile of the 51 cultivars, at the 6 evaluated loci, indicates that all can be distinguished from each other. In addition, this study produces information on the relationship of these 51 grapevine cultivars with cultivars of other important Mediterranean wine producing regions
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
New methodology for optimizing transit priority at the network level
A new methodology for optimizing transit road space priority at the network level is proposed. Transit vehicles carry large numbers of passengers within congested road space efficiently. This aids justification of transit priority. Almost all studies that have investigated transit priority lanes focus at a link or an arterial road level, and no study has investigated road space allocation for priority from a network perspective. The aim of the proposed approach is to find the optimum combination of exclusive lanes in an existing operational transport network. Mode share is assumed variable, and an assignment is performed for both private and transit traffic. The problem is formulated by using bilevel programming, which minimizes the total travel time. The approach is applied to an example network and the results are discussed. The approach can identify the optimal combination of transit priority lanes and achieve the global optimum of the objective function. Areas for further development are discussed
The Extended Emission-Line Region of 4C 37.43
We have explored the nature of the extended emission-line region around the
z=0.37 quasar 4C 37.43, using extensive ground-based and HST imaging and
spectroscopy. The velocity field of the ionized gas shows gradual gradients
within components but large jumps between components, with no obvious global
organization. The HST [O III] image shows radial linear features on the east
side of the QSO that appear to mark the edges of an ionization cone.
Concentrating on the bright emission peaks ~4\arcsec$ east of the quasar, we
find through modeling that we require at least two density regimes contributing
significantly to the observed emission-line spectrum: one with a density of ~2
cm^-3, having essentially unity filling factor, and one with a density of ~500
cm^-3, having a very small (~10^-5) filling factor. Because the temperatures of
these two components are similar, they cannot be in pressure equilibrium, and
there is no obvious source of confinement for the dense regions. We estimate
that the dense regions will dissipate on timescales <~10^4 years and therefore
need to be continuously regenerated, most likely by shocks. Because we know
that some QSOs, at least, begin their lives in conjunction with merger-driven
massive starbursts in their host galaxies, an attractive interpretation is that
the extended emission region comprises gas that has been expelled as a result
of tidal forces during the merger and is now being shocked by the galactic
superwind from the starburst. This picture is supported by the observed
distribution of the ionized gas, the presence of velocities ranging up to ~700
km s^{-1}, and the existence of at least two QSOs having similarly luminous and
complex extended emission regions that are known to have ultra-luminous IR
galaxy hosts with current or recent starbursts.Comment: 22 pages, incl. 7 figures; to be published in The Astrophysical
Journal, 572 (June 20, 2002 issue
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