5,623 research outputs found
Acoustic Emission Monitoring of a Ground Durability and Damage Tolerance Test
Since the mid-1970âs several authors have investigated the feasibility of using acoustic emission to monitor the integrity of aircraft structures. These studies, which have involved the monitoring of airframes during full scale ground fatigue tests as well as the monitoring of airframe components during flight, are completely catalogued in Drouillardâs annotated bibliography of acoustic emission [1,2]. In the future, acoustic emission is expected to play a primary role in the evaluation of the structural integrity of complex bolted structures such as airframes because of its ability to monitor large areas using a relatively small number of sensors. This work demonstrates the successful application to such a problem involving the monitoring of the lower wing skin of a fighter aircraft. The monitored area contained approximately 600 fasteners which attach the lower wing skin to the inner structure
Explaining variation in referral from primary to secondary care: cohort study
Objectives To determine the extent to which referral for defined symptoms from primary care varies by age, sex, and social deprivation and whether any sociodemographic variations in referral differ according to the presence of national referral guidance and the potential of the symptoms to be life threatening
Male circumcision and HIV transmission: what do we know?
Male circumcision (MC) has been shown to be protective against heterosexual HIV transmission and is being explored in some parts of the world as a means of combating the epidemic. The World Health Organization (WHO) recommends that MC be considered as an important component of HIV prevention in high prevalence settings.
We review evidence that demonstrates that the inner foreskin is likely to be the main portal of entry for the HIV virus in males. Whether removal of the inner foreskin accounts for all the protection afforded by circumcision is yet to be established.
The proposed mechanisms of protection range from inherent immunohistological factors of foreskin such as difference in thickness of keratin layer and density of target cells for HIV between inner and outer foreskin to physiological mechanisms that follow male circumcision such as drying of secretions underneath foreskin after sexual intercourse, loss of microbiome that attract target cells to the genital mucosa and lack of priming the genital mucosa with less abundant sexual transmitted infections among circumcised men.
The aim of this review is to give an updated account on the mechanisms proposed so far on the demonstrated 50-70% protection from HIV transmission through heterosexual intercourse, by male circumcision
Onset of experimental severe cardiac fibrosis is mediated by overexpression of angiotensin-converting enzyme 2
Angiotensin-converting enzyme (ACE) 2 is a recently identified homologue of ACE. There is great interest in the therapeutic benefit for ACE2 overexpression in the heart. However, the role of ACE2 in the regulation of cardiac structure and function, as well as maintenance of systemic blood pressure, remains poorly understood. In cell culture, ACE2 overexpression led to markedly increased myocyte volume, assessed in primary rabbit myocytes. To assess ACE2 function in vivo, we used a recombinant adeno-associated virus 6 delivery system to provide 11-week overexpression of ACE2 in the myocardium of stroke-prone spontaneously hypertensive rats. ACE2, as well as the ACE inhibitor enalapril, significantly reduced systolic blood pressure. However, in the heart, ACE2 overexpression resulted in cardiac fibrosis, as assessed by histological analysis with concomitant deficits in ejection fraction and fractional shortening measured by echocardiography. Furthermore, global gene expression profiling demonstrated the activation of profibrotic pathways in the heart mediated by ACE2 gene delivery. This study demonstrates that sustained overexpression of ACE2 in the heart in vivo leads to the onset of severe fibrosis
RUNX1: an emerging therapeutic target for cardiovascular disease
Runt-related transcription factor-1 (RUNX1), also known as acute myeloid leukaemia 1 protein (AML1), is a member of the core-binding factor family of transcription factors which modulate cell proliferation, differentiation, and survival in multiple systems. It is a master-regulator transcription factor, which has been implicated in diverse signalling pathways and cellular mechanisms during normal development and disease. RUNX1 is best characterized for its indispensable role for definitive haematopoiesis and its involvement in haematological malignancies. However, more recently RUNX1 has been identified as a key regulator of adverse cardiac remodelling following myocardial infarction. This review discusses the role RUNX1 plays in the heart and highlights its therapeutic potential as a target to limit the progression of adverse cardiac remodelling and heart failure
Trade unions and work-life balance: changing times in France and the UK?
The mixed empirical findings to date have indicated that some, but not all, unions in industrialized countries are actively involved in campaigning and bargaining around workâlife balance (WLB) issues, as part of a modernization
agenda linked to feminization and to âpositive flexibilityâ. This article seeks to identify factors that might encourage or inhibit trade unions from involvement
in WLB issues, within a cross-national comparative perspective focusing on two countries (France and the UK) that have contrasting working time regimes and approaches to WLB. It draws on original research carried out in two sectors â insurance and social work â in these two countries. The article links the emergence of union WLB programmes and bargaining agendas to genderequality concerns within the union and to the gender composition of the sector, as well as to the working time regime, including the mode of action, partnership being a significant corollary of WLB campaigning in the UK. We find support for the modernization thesis in the UK, particularly in the public sector, but within severe constraints defined by employer initiative
Palaeolithic extinctions and the Taurid Complex
Intersection with the debris of a large (50-100 km) short-period comet during
the Upper Palaeolithic provides a satisfactory explanation for the catastrophe
of celestial origin which has been postulated to have occurred around 12900 BP,
and which presaged a return to ice age conditions of duration ~1300 years. The
Taurid Complex appears to be the debris of this erstwhile comet; it includes at
least 19 of the brightest near-Earth objects. Sub-kilometre bodies in meteor
streams may present the greatest regional impact hazard on timescales of human
concern.Comment: 7 pages, 3 figures; accepted for Monthly Notices of the Royal
Astronomical Society (definitive version will be available at
www.blackwell-synergy.com
Community Attitudes and Practices of Urban Residents Regarding Predation by Pet Cats on Wildlife: An International Comparison
International differences in practices and attitudes regarding pet cats\u27 interactions with wildlife were assessed by surveying citizens from at least two cities in Australia, New Zealand, the UK, the USA, China and Japan. Predictions tested were: (i) cat owners would agree less than non-cat owners that cats might threaten wildlife, (ii) cat owners value wildlife less than non-cat owners, (iii) cat owners are less accepting of cat legislation/restrictions than non-owners, and (iv) respondents from regions with high endemic biodiversity (Australia, New Zealand, China and the USA state of Hawaii) would be most concerned about pet cats threatening wildlife. Everywhere non-owners were more likely than owners to agree that pet cats killing wildlife were a problem in cities, towns and rural areas. Agreement amongst nonowners was highest in Australia (95%) and New Zealand (78%) and lowest in the UK (38%). Irrespective of ownership, over 85% of respondents from all countries except China (65%) valued wildlife in cities, towns and rural areas. Non-owners advocated cat legislation more strongly than owners except in Japan. Australian non-owners were the most supportive (88%), followed by Chinese non-owners (80%) and Japanese owners (79.5%). The UK was least supportive (non-owners 43%, owners 25%). Many Australian (62%), New Zealand (51%) and Chinese owners (42%) agreed that pet cats killing wildlife in cities, towns and rural areas was a problem, while Hawaiian owners were similar to the mainland USA (20%). Thus high endemic biodiversity might contribute to attitudes in some, but not all, countries. Husbandry practices varied internationally, with predation highest where fewer cats were confined. Although the risk of wildlife population declines caused by pet cats justifies precautionary action, campaigns based on wildlife protection are unlikely to succeed outside Australia or New Zealand. Restrictions on roaming protect wildlife and benefit cat welfare, so welfare is a better rationale
Haloes gone MAD: The Halo-Finder Comparison Project
[abridged] We present a detailed comparison of fundamental dark matter halo
properties retrieved by a substantial number of different halo finders. These
codes span a wide range of techniques including friends-of-friends (FOF),
spherical-overdensity (SO) and phase-space based algorithms. We further
introduce a robust (and publicly available) suite of test scenarios that allows
halo finder developers to compare the performance of their codes against those
presented here. This set includes mock haloes containing various levels and
distributions of substructure at a range of resolutions as well as a
cosmological simulation of the large-scale structure of the universe. All the
halo finding codes tested could successfully recover the spatial location of
our mock haloes. They further returned lists of particles (potentially)
belonging to the object that led to coinciding values for the maximum of the
circular velocity profile and the radius where it is reached. All the finders
based in configuration space struggled to recover substructure that was located
close to the centre of the host halo and the radial dependence of the mass
recovered varies from finder to finder. Those finders based in phase space
could resolve central substructure although they found difficulties in
accurately recovering its properties. Via a resolution study we found that most
of the finders could not reliably recover substructure containing fewer than
30-40 particles. However, also here the phase space finders excelled by
resolving substructure down to 10-20 particles. By comparing the halo finders
using a high resolution cosmological volume we found that they agree remarkably
well on fundamental properties of astrophysical significance (e.g. mass,
position, velocity, and peak of the rotation curve).Comment: 27 interesting pages, 20 beautiful figures, and 4 informative tables
accepted for publication in MNRAS. The high-resolution version of the paper
as well as all the test cases and analysis can be found at the web site
http://popia.ft.uam.es/HaloesGoingMA
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