164 research outputs found
Human nutrition in Mongolia during economic liberalisation: available data and key research issues
Over the past two years, Mongolia has been attempting to move from a
largely Soviet-inspired command economy to one which is led by market
forces. Privatisation of the livestock, although not the grazing lands, of
pastoralist collective farms has been proceeding to various degrees in
different areas. This has taken place in a context in which, since the
ending of Soviet subsidies to satellite Asian republics in early 1991,
international trade in foodstuffs has been disrupted.
The consequences of this economic liberalisation for the nature of food
supplies have differed between states. Meat, milk, fruit and vegetables
have been hard to obtain in Kazakhstan, Kirghizstan, Tajikistan,
Turkmenistan and Uzbekistan (the Central Asian Republics - CAR states),
where consumption of bread and potatoes has risen sharply to compensate for
shortages of these items (Chen et al. 1992) . These changes broadly resemble
those which have affected some Eastern European states since the late
1980s, notably Poland (Szostak and Sekula 1991) but also some other
countries (Traill and Henson 1991). By contrast, in Mongolia the large
livestock sector has permitted increasing dependence on meat and milk, to
compensate for reductions in the absolute availability of flour and
vegetable foods. In both regions, there has therefore been concern over the
food security of groups vulnerable to poor health and nutrition. Baseline
information is central to understanding the nutritional correlates of
economic change in this case; and this paper therefore reviews available
data concerning nutrition in Mongolia with the aim of identifying specific
lines of inquiry for future nutritional research
Supersonic Cloud Collision - I
It has long been suggested that shocks might play an important role in
altering the form of the interstellar medium (ISM). Shocks enhance gas density
and sufficiently dense regions may become self gravitating. Potential star
forming clouds within larger molecular clouds, move randomly at supersonic
speeds.
Depending on the precollision velocity, colliding molecular clouds produce a
slab that is either shock compressed or pressure confined. In a sequel of two
papers (I & II), we simulate molecular cloud collision and investigate the
dynamical evolution of such slabs. Shocked slabs are susceptible to
hydrodynamic instabilities and in the present paper (I) we study the effect of
strong shear between slab layers on the dynamic evolution of a shock compressed
gas slab. Both, head-on and off-centre cloud collisions have been examined in
this work. We include self gravity in all our simulations.
Simulations presented here, are performed using the smoothed particle
hydrodynamics (SPH) numerical scheme. Individual, pre-collision clouds are
modelled as pressure confined Bonnor-Ebert spheres. However, in the interest of
brevity the thermodynamic details of the problem are simplified and the gas
temperature is simply evolved by a barytropic equation of state. Obviously, the
gas, to some extent suffers from thermal inertial effects. However, we note
that the dynamical timescale is much smaller than the local sound crossing time
so that such effects should have minimum influence.Comment: 16 pages, 13 figures, 1 table; A&A accepted Typographical errors have
been attended to. The resolution of the figures has been deliberately lowered
in order to accommodate them all within the prescribed size limit
Rosetta-Alice Observations of Exospheric Hydrogen and Oxygen on Mars
The European Space Agency's Rosetta spacecraft, en route to a 2014 encounter
with comet 67P/Churyumov-Gerasimenko, made a gravity assist swing-by of Mars on
25 February 2007, closest approach being at 01:54UT. The Alice instrument on
board Rosetta, a lightweight far-ultraviolet imaging spectrograph optimized for
in situ cometary spectroscopy in the 750-2000 A spectral band, was used to
study the daytime Mars upper atmosphere including emissions from exospheric
hydrogen and oxygen. Offset pointing, obtained five hours before closest
approach, enabled us to detect and map the HI Lyman-alpha and Lyman-beta
emissions from exospheric hydrogen out beyond 30,000 km from the planet's
center. These data are fit with a Chamberlain exospheric model from which we
derive the hydrogen density at the 200 km exobase and the H escape flux. The
results are comparable to those found from the the Ultraviolet Spectrometer
experiment on the Mariner 6 and 7 fly-bys of Mars in 1969. Atomic oxygen
emission at 1304 A is detected at altitudes of 400 to 1000 km above the limb
during limb scans shortly after closest approach. However, the derived oxygen
scale height is not consistent with recent models of oxygen escape based on the
production of suprathermal oxygen atoms by the dissociative recombination of
O2+.Comment: 17 pages, 8 figures, accepted for publication in Icaru
Putative degraders of low-density polyethylene-derived compounds are ubiquitous members of plastic associated bacterial communities in the marine environment
Research articleIt remains unknown whether and to what extent marine prokaryotic communities are capable of degrading plastic in the ocean. To address this knowledge gap, we combined enrichment experiments employing low-density polyethylene (LDPE) as the sole carbon source with a comparison of bacterial communities on plastic debris in the Pacific, the North Atlantic and the northern Adriatic Sea. A total of 35 operational taxonomic units (OTUs) were enriched in the LDPE-laboratory incubations after 1 year, of which 20 were present with relative abundances > 0.5% in at least one plastic sample collected from the environment. From these, OTUs classified as Cognatiyoonia, Psychrobacter, Roseovarius and Roseobacter were found in the communities of plastics collected at all oceanic sites. Additionally, OTUs classified as Roseobacter, Pseudophaeobacter, Phaeobacter, Marinovum and Cognatiyoonia, also enriched in the LDPE-laboratory incubations, were enriched on LDPE communities compared to the ones associated to glass and polypropylene in in-situ incubations in the northern Adriatic Sea after 1 month of incubation. Some of these enriched OTUs were also related to known alkane and hydrocarbon degraders. Collectively, these results demonstrate that there are prokaryotes capable of surviving with LDPE as the sole carbon source living on plastics in relatively high abundances in different water masses of the global ocean.Austrian Academy of Sciences, Austrian Sciences Fund, University of Viena, German Federal Ministry of Education and Science (BacGeoPac project (03G0248A) and IEO (RADPROF project)Versión del editor5,84
Sec61alpha synthesis is enhanced during translocation of nascent chains of collagen type IV in F9 teratocarcinoma cells after retinoic acid treatment
Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at GeV
We present first measurements of the evolution of the differential transverse
momentum correlation function, {\it C}, with collision centrality in Au+Au
interactions at GeV. {\it C} exhibits a strong dependence
on collision centrality that is qualitatively similar to that of number
correlations previously reported. We use the observed longitudinal broadening
of the near-side peak of {\it C} with increasing centrality to estimate the
ratio of the shear viscosity to entropy density, , of the matter formed
in central Au+Au interactions. We obtain an upper limit estimate of
that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.
Inhibition of Histone Deacetylase Activity in Human Endometrial Stromal Cells Promotes Extracellular Matrix Remodelling and Limits Embryo Invasion
Invasion of the trophoblast into the maternal decidua is regulated by both the trophoectoderm and the endometrial stroma, and entails the action of tissue remodeling enzymes. Trophoblast invasion requires the action of metalloproteinases (MMPs) to degrade extracellular matrix (ECM) proteins and in turn, decidual cells express tissue inhibitors of MMPs (TIMPs). The balance between these promoting and restraining factors is a key event for the successful outcome of pregnancy. Gene expression is post-transcriptionally regulated by histone deacetylases (HDACs) that unpacks condensed chromatin activating gene expression. In this study we analyze the effect of histone acetylation on the expression of tissue remodeling enzymes and activity of human endometrial stromal cells (hESCs) related to trophoblast invasion control. Treatment of hESCs with the HDAC inhibitor trichostatin A (TSA) increased the expression of TIMP-1 and TIMP-3 while decreased MMP-2, MMP-9 and uPA and have an inhibitory effect on trophoblast invasion. Moreover, histone acetylation is detected at the promoters of TIMP-1 and TIMP-3 genes in TSA-treated. In addition, in an in vitro decidualized hESCs model, the increase of TIMP-1 and TIMP-3 expression is associated with histone acetylation at the promoters of these genes. Our results demonstrate that histone acetylation disrupt the balance of ECM modulators provoking a restrain of trophoblast invasion. These findings are important as an epigenetic mechanism that can be used to control trophoblast invasion
An Expert Consensus Statement on the Management of Large Chondral and Osteochondral Defects in the Patellofemoral Joint
© The Author(s) 2020. Background: Cartilage lesions of the patellofemoral joint constitute a frequent abnormality. Patellofemoral conditions are challenging to treat because of complex biomechanics and morphology. Purpose: To develop a consensus statement on the functional anatomy, indications, donor graft considerations, surgical treatment, and rehabilitation for the management of large chondral and osteochondral defects in the patellofemoral joint using a modified Delphi technique. Study Design: Consensus statement. Methods: A working group of 4 persons generated a list of statements related to the functional anatomy, indications, donor graft considerations, surgical treatment, and rehabilitation for the management of large chondral and osteochondral defects in the patellofemoral joint to form the basis of an initial survey for rating by a group of experts. The Metrics of Osteochondral Allografts (MOCA) expert group (composed of 28 high-volume cartilage experts) was surveyed on 3 occasions to establish a consensus on the statements. In addition to assessing agreement for each included statement, experts were invited to propose additional statements for inclusion or to suggest modifications of existing statements with each round. Predefined criteria were used to refine statement lists after each survey round. Statements reaching a consensus in round 3 were included within the final consensus document. Results: A total of 28 experts (100% response rate) completed 3 rounds of surveys. After 3 rounds, 36 statements achieved a consensus, with over 75% agreement and less than 20% disagreement. A consensus was reached in 100.00% of the statements relating to functional anatomy of the patellofemoral joint, 88.24% relating to surgical indications, 100.00% relating to surgical technical aspects, and 100.00% relating to rehabilitation, with an overall consensus of 95.5%. Conclusion: This study established a strong expert consensus document relating to the functional anatomy, surgical indications, donor graft considerations for osteochondral allografts, surgical technical aspects, and rehabilitation concepts for the management of large chondral and osteochondral defects in the patellofemoral joint. Further research is required to clinically validate the established consensus statements and better understand the precise indications for surgery as well as which techniques and graft processing/preparation methods should be used based on patient- and lesion-specific factors
A Conditioning Lesion Provides Selective Protection in a Rat Model of Amyotrophic Lateral Sclerosis
Amyotrophic Lateral Sclerosis (ALS) is neurodegenerative disease characterized by muscle weakness and atrophy due to progressive motoneuron loss. The death of motoneuron is preceded by the failure of neuromuscular junctions (NMJs) and axonal retraction. Thus, to develop an effective ALS therapy you must simultaneously preserve motoneuron somas, motor axons and NMJs. A conditioning lesion has the potential to accomplish this since it has been shown to enhance neuronal survival and recovery from trauma in a variety of contexts. rats that received a conditioning lesion was delayed and less severe. These improvements in motor function corresponded to greater motoneuron survival, reduced motor axonopathy, and enhanced NMJ maintenance at disease end-stage. Furthermore, the increased NMJ maintenance was selective for muscle compartments innervated by the most resilient (slow) motoneuron subtypes, but was absent in muscle compartments innervated by the most vulnerable (fast fatigable) motoneuron subtypes.These findings support the development of strategies aimed at mimicking the conditioning lesion effect to treat ALS as well as underlined the importance of considering the heterogeneity of motoneuron sub-types when evaluating prospective ALS therapeutics
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