677 research outputs found
A magnetically collimated jet from an evolved star
Planetary nebulae often have asymmetric shapes, which could arise due to
collimated jets from evolved stars before evolution to the planetary nebula
phase. The source of jet collimation in these stars is unknown. Magnetic fields
are thought to collimate outflows that are observed in many other astrophysical
sources, such as active galactic nuclei and proto-stars, although hitherto
there are no direct observations of both the magnetic field direction and
strength in any collimated jet. Theoretical models have shown that magnetic
fields could also be the dominant source of collimation of jet in evolved
stars. Here we report measurements of the polarization of water vapour masers
that trace the precessing jet emanating from the asymptotic giant branch star
W43A at 2.6 kpc from the Sun, which is undergoing rapid evolution into a
planetary nebula. The masers occur in two clusters at opposing tips of the
jets, ~1,000 AU from the star. We find direct evidence that the magnetic field
is collimating the jet.Comment: Published in Nature 440 (March 2nd 2006). High-res figures can be
found at http://www.jb.man.ac.uk/~wouter/papers/w43a/w43a.htm
SIP: Optimal Product Selection from Feature Models using Many-Objective Evolutionary Optimisation
© ACM, 2016. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in ACM Transactions on Software Engineering and Methodology, Vol. 25, No. 2, Article 17, Publication date: April 2016. https://doi.acm.org/10.1145/2897760The European Commission (FEDER) and Spanish Government under CICYT project TAPAS (TIN2012-32273) and the Andalusian Government projects THEOS (TIC-5906) and COPAS (P12-TIC-1867
CHRONOFALLS: A multicentre nurse-led intervention in the chronoprevention of in-hospital falls in adults
Background: Falls are among the most common and serious adverse events for hospitalised patients. In-hospital falls pose a major medical and economic challenge for public health worldwide. Nevertheless, the issue is often addressed without regard to certain relevant variables such as the time of the fall. The aim of this study was to determine the effect of the implementation of a nurse-led intervention based on the temporal patterns of falls and their aetiology on the occurrence of falls.
Methods: A mixed-method research design was carried out in three phases: a) a longitudinal prospective study (audits, chronobiological analyses and implementation of a multicentre nurse-led intervention based on temporal patterns of falls); b) a retrospective study of fall records; and c) a qualitative study based on focus groups. The protocol was published in 2021.
Results: A difference was observed in the number of fall records before and after the chronopreventive intervention (retrospective: 64.4% vs. 35.6%; p < 0,001). According to the interrupted series analysis, considering the influence of the COVID-19 pandemic, a reduction in falls of 2.96% (95% CI 1.70%-4.17%) was observed. The concepts of falls, the COVID-19 pandemic and the causes of non-registration have emerged as categories for qualitative analysis.
Conclusions: A multicentric nurse-led program based on tailored organisational, educational and behavioural chronopreventive measures seems to lead to a reduction in the number of in-hospital falls. The findings of the present study, highlighting the implementation of chronopreventive measures, can serve as a basis for future health policies
Anàlisi de la concentració sèrica de vitamina D com a factor de risc de càncer de pròstata i agressivitat tumoral
Alguns estudis observacionals han suggerit que el dèficit de vitamina D podria relacionar-se amb un major risc de càncer de pròstata i amb una major incidència en àrees geogràfiques de menor insolació. L'objectiu d'aquest estudi ha sigut relacionar els nivells sèrics de vitamina D i parathormona amb el risc de càncer de pròstata i amb la agressivitat tumora
Robustness Testing of Intermediate Verifiers
Program verifiers are not exempt from the bugs that affect nearly every piece
of software. In addition, they often exhibit brittle behavior: their
performance changes considerably with details of how the input program is
expressed-details that should be irrelevant, such as the order of independent
declarations. Such a lack of robustness frustrates users who have to spend
considerable time figuring out a tool's idiosyncrasies before they can use it
effectively.
This paper introduces a technique to detect lack of robustness of program
verifiers; the technique is lightweight and fully automated, as it is based on
testing methods (such as mutation testing and metamorphic testing). The key
idea is to generate many simple variants of a program that initially passes
verification. All variants are, by construction, equivalent to the original
program; thus, any variant that fails verification indicates lack of robustness
in the verifier.
We implemented our technique in a tool called "mugie", which operates on
programs written in the popular Boogie language for verification-used as
intermediate representation in numerous program verifiers. Experiments
targeting 135 Boogie programs indicate that brittle behavior occurs fairly
frequently (16 programs) and is not hard to trigger. Based on these results,
the paper discusses the main sources of brittle behavior and suggests means of
improving robustness
Marked alveolar apoptosis/proliferation imbalance in end-stage emphysema
BACKGROUND: Apoptosis has recently been proposed to contribute to the pathogenesis of emphysema. METHODS: In order to establish if cell fate plays a role even in end-stage disease we studied 16 lungs (9 smoking-associated and 7 α1antitrypsin (AAT)-deficiency emphysema) from patients who had undergone lung transplantations. Six unused donor lungs served as controls. Apoptosis was evaluated by TUNEL analysis, single-stranded DNA laddering, electron microscopy and cell proliferation by an immunohistochemical method (MIB1). The role of the transforming growth factor (TGF)-β1 pathway was also investigated and correlated with epithelial cell turnover and with the severity of inflammatory cell infiltrate. RESULTS: The apoptotic index (AI) was significantly higher in emphysematous lungs compared to the control group (p ≤ 0.01), particularly if only lungs with AAT-deficiency emphysema were considered (p ≤ 0.01 vs p = 0.09). The proliferation index was similar in patients and controls (1.9 ± 2.2 vs 1.7 ± 1.1). An increased number of T lymphocytes was observed in AAT-deficiency lungs than smoking-related cases (p ≤ 0.05). TGF-β1 expression in the alveolar wall was higher in patients with smoking-associated emphysema than in cases with AAT-deficiency emphysema (p ≤ 0.05). A positive correlation between TGF-βRII and AI was observed only in the control group (p ≤ 0.005, r(2 )= 0.8). A negative correlation was found between the TGF-β pathway (particularly TGF-βRII) and T lymphocytes infiltrate in smoking-related cases (p ≤ 0.05, r(2 )= 0.99) CONCLUSION: Our findings suggest that apoptosis of alveolar epithelial cells plays an important role even in end-stage emphysema particularly in AAT-deficiency disease. The TGFβ-1 pathway does not seem to directly influence epithelial turnover in end-stage disease. Inflammatory cytokine different from TGF-β1 may differently orchestrate cell fate in AAT and smoking-related emphysema types
Characterising the Mucosal and Systemic Immune Responses to Experimental Human Hookworm Infection
The mucosal cytokine response of healthy humans to parasitic helminths has never been reported. We investigated the systemic and mucosal cytokine responses to hookworm infection in experimentally infected, previously hookworm naive individuals from non-endemic areas. We collected both peripheral blood and duodenal biopsies to assess the systemic immune response, as well as the response at the site of adult worm establishment. Our results show that experimental hookworm infection leads to a strong systemic and mucosal Th2 (IL-4, IL-5, IL-9 and IL-13) and regulatory (IL-10 and TGF-β) response, with some evidence of a Th1 (IFN-γ and IL-2) response. Despite upregulation after patency of both IL-15 and ALDH1A2, a known Th17-inducing combination in inflammatory diseases, we saw no evidence of a Th17 (IL-17) response. Moreover, we observed strong suppression of mucosal IL-23 and upregulation of IL-22 during established hookworm infection, suggesting a potential mechanism by which Th17 responses are suppressed, and highlighting the potential that hookworms and their secreted proteins offer as therapeutics for human inflammatory diseases
Estrogen protects neuronal cells from amyloid beta-induced apoptosis via regulation of mitochondrial proteins and function
BACKGROUND: Neurodegeneration in Alzheimer's disease is associated with increased apoptosis and parallels increased levels of amyloid beta, which can induce neuronal apoptosis. Estrogen exposure prior to neurotoxic insult of hippocampal neurons promotes neuronal defence and survival against neurodegenerative insults including amyloid beta. Although all underlying molecular mechanisms of amyloid beta neurotoxicity remain undetermined, mitochondrial dysfunction, including altered calcium homeostasis and Bcl-2 expression, are involved in neurodegenerative vulnerability. RESULTS: In this study, we investigated the mechanism of 17β-estradiol-induced prevention of amyloid beta-induced apoptosis of rat hippocampal neuronal cultures. Estradiol treatment prior to amyloid beta exposure significantly reduced the number of apoptotic neurons and the associated rise in resting intracellular calcium levels. Amyloid beta exposure provoked down regulation of a key antiapoptotic protein, Bcl-2, and resulted in mitochondrial translocation of Bax, a protein known to promote cell death, and subsequent release of cytochrome c. E(2 )pretreatment inhibited the amyloid beta-induced decrease in Bcl-2 expression, translocation of Bax to the mitochondria and subsequent release of cytochrome c. Further implicating the mitochondria as a target of estradiol action, in vivo estradiol treatment enhanced the respiratory function of whole brain mitochondria. In addition, estradiol pretreatment protected isolated mitochondria against calcium-induced loss of respiratory function. CONCLUSION: Therefore, we propose that estradiol pretreatment protects against amyloid beta neurotoxicity by limiting mitochondrial dysfunction via activation of antiapoptotic mechanisms
Identification of a Common Lupus Disease-Associated microRNA Expression Pattern in Three Different Murine Models of Lupus
Recent reports have shown that microRNAs (miRNAs) regulate vital immunological processes and have emerged as key regulators of immune system development and function. Therefore, it is important to determine miRNA dysregulation and its pathogenic contribution in autoimmune diseases, an aspect not adequately addressed thus far.In this study, we profiled miRNA expressions in splenic lymphocytes from three murine lupus models (MRL-lpr, B6-lpr and NZB/W(F₁)) with different genetic background by miRNA microarray assays and Real-time RT-PCR. Despite the genetic differences among these three lupus stains, a common set of dysregulated miRNAs (miR-182-96-183 cluster, miR-31, and miR-155) was identified in splenocytes when compared with age-matched control mice. The association of these miRNAs with the disease was highlighted by our observation that this miRNA expression pattern was evident in NZB/W mice only at an age when lupus disease is manifested. Further, we have shown that the miRNA dysregulation in MRL-lpr mice was not simply due to the activation of splenocytes. By Real-time RT-PCR, we confirmed that these miRNAs were upregulated in both purified splenic B and T cells from MRL-lpr mice. miR-127 and miR-379, which were greatly upregulated in splenocytes from lpr mice, were moderately increased in diseased NZB/W mice. In addition, Real-time RT-PCR revealed that miR-146a, miR-101a, and miR-17-92 were also markedly upregulated in splenic T, but not B cells from MRL-lpr mice.The identification of common lupus disease-associated miRNAs now forms the basis for the further investigation of the pathogenic contribution of these miRNAs in autoimmune lupus, which will advance our knowledge of the role of miRNAs in autoimmunity. Given that miRNAs are conserved, with regard to both evolution and function, our observation of a common lupus disease-associated miRNA expression pattern in murine lupus models is likely to have significant pathogenic, diagnostic, and/or therapeutic implications in human lupus
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