417 research outputs found
ASCA observations of the nearby galaxies Dwingeloo 1 and Maffei 1
We present ASCA observations of the nearby galaxies Dwingeloo 1 (Dw1) and
Maffei 1 (Mf1). X-ray sources are clearly detected within 3 arcminutes of the
optical nuclei of both galaxies. Despite the low Galactic latitude of these
fields (|b|<1\degmark) we conclude, on probability and spectral grounds, that
the detected sources are intrinsic to these galaxies rather than foreground or
background interlopers. The Dw1 source, designated Dw1-X1, is interpreted as
being either a hyper-luminous X-ray binary (with a 0.5--10\,keV luminosity of
more than 10^{39}\ergps) or an X-ray bright supernova. The Mf1 emission is
hard and extended, suggesting that it originates from a population of X-ray
binaries. Prompted by the Dw1-X1 results, we discuss the nature of
hyper-luminous X-ray binary systems. Such sources are commonly seen in nearby
galaxies with a frequency of approximately one per galaxy. We present a
possible connection between these luminous systems and Galactic superluminal
sources.Comment: 9 pages (4 ps figures included). Accepted for publication in MNRAS.
Higher quality reproductions of Figure 1 available upon reques
Superficial Palmar Arch Aneurysm after Carpal Tunnel Decompression, a Rare Complication: A Case Report
False aneurysms of the palmar arteries are rare. They are usually associated with traumatic injuries to the hand vasculature. We present a case of superficial palmar arch aneurysm (SPAA), complicating carpal tunnel decompression which presented as a pulsatile mass at the site of previous surgery. Initial diagnosis was made on clinical examination and confirmed on doppler ultrasound (US) and computed tomographic angiography (CTA). The feeding vessel of the aneurysm was subsequently occluded using coil embolization
Long-term survival and five year hospital resource usage following traumatic brain injury in Scotland from 1997 to 2015: A population-based retrospective cohort study
An Infrared Determination of the Reddening and Distance to Dwingeloo 1
We present for the first time infrared observations of the nearby highly
obscured galaxy Dwingeloo 1 (Dw1), including deep H-band imaging covering a
total of 4.9x4.9 arcmin, together with J and Ks imaging of the central 2.5x2.5
arcmin. We used the small dispersion of the intrinsic infrared colors of spiral
galaxies to determine an infrared H-band extinction of A_H = 0.47+/-0.11 mag
towards Dw1. In using infrared colors, the uncertainties in the reddening and
distance are reduced by a factor of three. The H-band magnitude corrected for
extinction and the infrared Tully-Fisher relation are then used to estimate a
distance modulus of (m-M)_0 = 28.62+/-0.27, and thus a distance of d = 5.3
{+0.7/-0.6} Mpc, which puts Dw1 at the far end of the IC342/Maffei 1 & 2 group.
Our result is largely independent of the nature of the reddening law because we
estimated both the reddening and the distance at the same wavelength range.Comment: 20 pages, 2 figures, see
http://nicmos2.as.arizona.edu/~aalonso/Dw1/dw1_paper.htm
Preschool Participation and the Cognitive and Social Development of Language-Minority Students
This study examined participation in preschool and its relationship with the cognitive and social development of language minority students. Although there is a large body of research that demonstrates the cognitive and social benefits of attending preschool (Barnett, 1995; Gorey, 2001; National Research Council, Committee on Early Childhood Pedagogy, 2000; Vandell, 2004), very little of this research has included language minority students, or at least those who do not speak English. Either non-English speaking families are not included in the design of the study, such as with the widely cited National Institute for Child Health and Development (NICHD) Early Child Care Study, or the studies are based on cognitive and social assessments that are only conducted in English (e.g., Magnuson, Meyers, Ruhm, & Waldfogel, 2004). Consequently, little is known about participation in and outcomes of preschool for the growing population of language minority students
Activation of Nrf2 to optimise immune responses to intracerebral haemorrhage
Haemorrhage into the brain parenchyma can be devastating. This manifests as spontaneous intracerebral haemorrhage (ICH) after head trauma, and in the context of vascular dementia. Randomised controlled trials have not reliably shown that haemostatic treatments aimed at limiting ICH haematoma expansion and surgical approaches to reducing haematoma volume are effective. Consequently, treatments to modulate the pathophysiological responses to ICH, which may cause secondary brain injury, are appealing. Following ICH, microglia and monocyte derived cells are recruited to the peri-haematomal environment where they phagocytose haematoma breakdown products and secrete inflammatory cytokines, which may trigger both protective and harmful responses. The transcription factor Nrf2, is activated by oxidative stress, is highly expressed by central nervous system microglia and macroglia. When active, Nrf2 induces a transcriptional programme characterised by increased expression of antioxidant, haem and heavy metal detoxification and proteostasis genes, as well as suppression of proinflammatory factors. Therefore, Nrf2 activation may facilitate adaptive-protective immune cell responses to ICH by boosting resistance to oxidative stress and heavy metal toxicity, whilst limiting harmful inflammatory signalling, which can contribute to further blood brain barrier dysfunction and cerebral oedema. In this review, we consider the responses of immune cells to ICH and how these might be modulated by Nrf2 activation. Finally, we propose potential therapeutic strategies to harness Nrf2 to improve the outcomes of patients with ICH
Coronavirus and Pasteurella infections in bovine shipping fever pneumonia and Evans\u27 criteria for causation
Respiratory tract infections with viruses and Pasteurella spp. were determined sequentially among 26 cattle that died during two severe epizootics of shipping fever pneumonia. Nasal swab and serum samples were collected prior to onset of the epizootics, during disease progression, and after death, when necropsies were performed and lung samples were collected. Eighteen normal control cattle also were sampled at the beginning of the epizootics as well as at weekly intervals for 4 weeks. Respiratory bovine coronaviruses (RBCV) were isolated from nasal secretions of 21 and 25 cattle before and after transport. Two and 17 cattle nasally shed Pasteurella spp. before and after transport, respectively. RBCV were isolated at titers of 1 x 103 to 1.2 x 107 PFU per g of lung tissue from 18 cattle that died within 7 days of the epizootics, but not from the lungs of the remaining cattle that died on days 9 to 36. Twenty-five of the 26 lung samples were positive for Pasteurella spp., and their CFU ranged between 4.0 x 105 and 2.3 x 109 per g. Acute and subacute exudative, necrotizing lobar pneumonia characterized the lung lesions of these cattle with a majority of pneumonic lung lobes exhibiting fibronecrotic and exudative changes typical of pneumonic pasteurellosis, but other lung lobules had histological changes consisting of bronchiolitis and alveolitis typical of virus-induced changes. These cattle were immunologically naive to both infectious agents at the onset of the epizootics, but those that died after day 7 had rising antibody titers against RBCV and Pasteurella haemolytica. In contrast, the 18 clinically normal and RBCV isolation-negative cattle had high hemagglutinin inhibition antibody titers to RBCV from the beginning, while their antibody responses to P. haemolytica antigens were delayed. Evans\u27 criteria for causation were applied to our findings because of the multifactorial nature of shipping fever pneumonia. This analysis identified RBCV as the primary inciting cause in these two epizootics. These viruses were previously not recognized as a causative agent in this complex respiratory tract disease of cattle
A two-step learning approach for solving full and almost full cold start problems in dyadic prediction
Dyadic prediction methods operate on pairs of objects (dyads), aiming to
infer labels for out-of-sample dyads. We consider the full and almost full cold
start problem in dyadic prediction, a setting that occurs when both objects in
an out-of-sample dyad have not been observed during training, or if one of them
has been observed, but very few times. A popular approach for addressing this
problem is to train a model that makes predictions based on a pairwise feature
representation of the dyads, or, in case of kernel methods, based on a tensor
product pairwise kernel. As an alternative to such a kernel approach, we
introduce a novel two-step learning algorithm that borrows ideas from the
fields of pairwise learning and spectral filtering. We show theoretically that
the two-step method is very closely related to the tensor product kernel
approach, and experimentally that it yields a slightly better predictive
performance. Moreover, unlike existing tensor product kernel methods, the
two-step method allows closed-form solutions for training and parameter
selection via cross-validation estimates both in the full and almost full cold
start settings, making the approach much more efficient and straightforward to
implement
- âŠ