5,787 research outputs found
A Common Origin for Quasar Extended Emission-Line Regions and Their Broad-Line Regions
We present a correlation between the presence of luminous extended
emission-line regions (EELRs) and the metallicity of the broad-line regions
(BLRs) of low-redshift quasars. The result is based on ground-based [O III]
5007 narrow-band imaging and Hubble Space Telescope UV spectra of 12 quasars at
0.20 < z < 0.45. Quasars showing luminous EELRs have low-metallicity BLRs (Z <
0.6 Z_Solar), while the remaining quasars show typical metal-rich gas (Z >
Z_Solar). Previous studies have shown that EELRs themselves also have low
metallicities (Z < 0.5 Z_Solar). The correlation between the occurrence of
EELRs and the metallicity of the BLRs, strengthened by the sub-Solar
metallicity in both regions, indicates a common external origin for the gas,
almost certainly from the merger of a gas-rich galaxy. Our results provide the
first direct observational evidence that the gas from a merger can indeed be
driven down to the immediate vicinity (< 1 pc) of the central black hole.Comment: Accepted for publication in ApJ Letters. 4 pages, 1 figure, 1 tabl
Metabolic reprogramming of murine cardiomyocytes during autophagy requires the extracellular nutrient sensor decorin.
The extracellular matrix is a master regulator of tissue homeostasis in health and disease. Here we examined how the small, leucine-rich, extracellular matrix proteoglycan decorin regulates cardiomyocyte metabolism during fasting in vivo. First, we validated in Dcn-/- mice that decorin plays an essential role in autophagy induced by fasting. High-Throughput metabolomics analyses of cardiac tissue in Dcn-/- mice subjected to fasting revealed striking differences in the hexosamine biosynthetic pathway resulting in aberrant cardiac O-β-N-Acetylglycosylation as compared with WT mice. Functionally, Dcn-/- mice maintained cardiac function at a level comparable with nonfasted animals whereas fasted WT mice showed reduced ejection fraction. Collectively, our results suggest that reduced sensing of nutrient deprivation in the absence of decorin preempts functional adjustments of cardiac output associated with metabolic reprogramming. © 2018 Gubbiotti et al
A Framework for analyzing socioeconomic, health and environmental impacts of wastewater use in agriculture in developing countries
Waste water management / Environmental degradation / Waterborne diseases / Water quality / Irrigation practices / Aquaculture / Economic analysis / Social aspects / Health / Environmental aspects / Agriculture / Developing countries / Policy
Використання математичного сподівання для швидкого центрування наборів зображень
There is proposed RSA algorithm modification on the based of the form of pixel threads. The used picture must be in the one byte pixel format and allows contour separation
The evolution of the stellar populations in low surface brightness galaxies
We investigate the star formation history and chemical evolution of low
surface brightness (LSB) disk galaxies by modelling their observed
spectro-photometric and chemical properties using a galactic chemical and
photometric evolution model incorporating a detailed metallicity depen dent set
of stellar input data. For a large fraction of the LSB galaxies in our sample,
observed properties are best explained by models incorporating an exponentially
decreasing global star formation rate (SFR) ending at a present-day gas
fraction (M_{gas}/(M_{gas}+M_{stars}) = 0.5 for a galaxy age of 14 Gyr. For
some galaxies small amplitude star formation bursts are required to explain the
contribution of the young (5-50 Myr old) stellar population to the galaxy
integrated luminosity. This suggests that star formation has proceeded in a
stochastic manner.
The presence of an old stellar population in many late-type LSB galaxies
suggests that LSB galaxies roughly follow the same evolutionary history as HSB
galaxies, except at a much lower rate. In particular, our results imply that
LSB galaxies do not form late, nor have a delayed onset of star formation, but
simply evolve slowly.Comment: To be published in A&
Malaria and land use: a spatial and temporal risk analysis in Southern Sri Lanka
Malaria / Waterborne diseases / Disease vectors / Land use / Water use / GIS / Statistical analysis / Risks / Mapping / Public health / Sri Lanka / Uda Walawe / Thanamalvila / Embilipitiya
Biochemical Effects of Exercise on a Fasciocutaneous Flap in a Rat Model.
Importance: An overwhelming amount of data suggest that cardiovascular exercise has a positive effect on the mind and body, although the precise mechanism is not always clear.
Objective: To assess the clinical and biochemical effects of voluntary cardiovascular exercise on pedicled flaps in a rodent model.
Design, Setting, and Participants: Eighteen adult Sprague-Dawley male rats were randomized into a resting animal group (RAG) (n=9) and an exercise animal group (EAG) (n=9) for 14 days (July 23, 2013, through July 30, 2013). A pedicled transposition flap was performed on the ventral surface of the rat, and biopsy specimens were taken from the proximal, middle, and distal portions on postoperative days 0, 2, 5, and 9. Flap survival was analyzed planimetrically, and biopsy specimens were analyzed by hematoxylin-eosin-stained microscopy and immunoblotting. The housing, exercise, surgery, and analysis of the rats were conducted at a single basic science research laboratory at the tertiary care center campus of Thomas Jefferson University in Philadelphia, Pennsylvania.
Exposures: The rats were caged for 14 days or housed in a cage connected to an exercise wheel and pedometer.
Main Outcomes and Measures: Study measures were gross and micrographic necrosis and expression of proteins within cell survival and apoptosis pathways.
Results: A total of 18 rats were studied, 9 in the RAG and 9 in the EAG. the mean (SEM) amount of necrosis in flaps was 41.3% (3%) in the RAG rats and 10.5% (3.5%) in the EAG rats (P \u3c .001). Immunoblotting revealed increased Caspase-9 activity resulting in poly-(adenosine diphosphate-ribose) polymerase 1 cleavage in the RAG vs the EAG, as well as lower phosphorylated protein kinase B (also known as Akt), signal transducer and activator of transcription 3, and total B-cell leukemia/lymphoma 2 protein levels. Throughout the postoperative period, the cumulative vascular endothelial growth factor A levels of the EAG flaps were significantly higher than those of the RAG flaps (2.30 vs 1.25 fold induction [FI], P = .002), with differences of 2.76 vs 1.54 FI in the proximal segment, 2.40 vs 1.20 FI in the middle segment, and 1.90 vs 0.79 FI in the distal segment. A similar response was noted when comparing phosphorylated Akt, with cumulative mean (SEM) p-Akt expression levels of 0.62 (0.04) for RAG and 1.98 (0.09) for EAG (P = .002 between the 2 groups).
Conclusions and Relevance: Voluntary preoperative exercise improves survival in pedicled fasciocutaneous flaps; the EAG rats had less necrosis, decreased apoptotic markers, and increased amounts of vascular endothelial growth factor A and prosurvival proteins. These results have implications to increase flap survival in other mammal populations, such as humans.
Level of Evidence: 3
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Assessing children's swallowing: Parent and professional perceptions
Purpose-For infants and children who have difficulties with eating, drinking and swallowing (dysphagia), there are significant health risks that include aspiration (food and fluid entering the lungs) and poor growth. Videofluoroscopy is often the instrumental method of assessment used to exclude or confirm aspiration. The purpose of this paper is to investigate parental and referrer perceptions of the reasons for and the outcomes of videofluoroscopy.
Design/methodology/approach-Data were gathered through the use of structured telephone interviews before and after videofluoroscopy.
Findings-Four key themes emerged: first, the importance of identifying specifically the problems with swallowing; second, understanding the rationale for videofluoroscopy; third, preparing a child for videofluoroscopy; and fourth, using videofluoroscopy to inform management. Referrers used videofluoroscopy to confirm their concerns about a child's ability to swallow safely.
Practical implications-Parents understood that the purpose of videofluoroscopy was to identify specific swallowing difficulties. They reported anxieties with managing the child's positioning during the procedure and whether the child would eat. They also had concerns about outcomes from the study. Some of these issues raise questions about the true value and benefits of videofluoroscopy.
Originality/value-This is the first study that considers parent views of an instrumental assessment. For some parents of children with learning disabilities, mealtimes are an important social occasion. Further studies that focus on decision making about children with learning disabilities who find feeding difficult are warranted as parents feel loss and disempowerment when decisions are made about non-oral feeding
The undecidability of arbitrary arrow update logic
Arbitrary Arrow Update Logic is a dynamic modal logic with a modality to quantify over arrow updates. Some properties of this logic have already been established, but until now it remained an open question whether the logic's satisfiability problem is decidable. Here, we show by a reduction of the tiling problem that the satisfiability problem of Arbitrary Arrow Update Logic is co-RE hard, and therefore undecidable
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