WSO/UV: World Space Observatory/Ultraviolet

We summarize the capabilities of the World Space Observatory (UV) Project (WSO/UV). An example of the importance of this project (with a planned launch date of 2007/8) for the study of Classical Novae is given.Comment: 4 pages, To appear in the proceeedings of the "Classical Nova Explosions" conference, eds. M. Hernanz and J. Jose, AI

Older hip fracture patients: three groups with different needs

BACKGROUND: Norway, and particularly Oslo, has the highest reported incidence of hip fractures in the world. It is increasingly common to care for older hip fracture patients in orthogeriatric units where orthopaedic care is combined with interdisciplinary geriatric care. The characteristics and needs of older hip fracture patients are poorly described. The aim of this paper is to describe the characteristics of these patients in order to better understand their need for care and rehabilitation. METHODS: This is an observational study based on a quality register for all patients 65+ years in an orthogeriatric unit who are operated for a hip fracture. The unit covers 250,000 inhabitants in Oslo. Patient data were collected in the aim of quality control. The quality database includes demographic, medical, and functional data collected from routine assessment by the interdisciplinary team. RESULTS: From January 2007 to September 2009, 1010 patients, included 241 (24%) from long-term care institutions, were enrolled in the database. Mean age was 85.1 years (SD 7.1), 76% were female, and 83% had experienced an indoor fall. Chronic diseases were registered in 88%, and 38% of the community-dwelling patients had pre-fracture cognitive impairment defined as IQCODE-SF > 3.6. Complications were observed in 51% of the patients, of which the most common were a need for blood transfusion, delirium, and urinary tract infections. Post-operative orthopaedic infections were rare (3.1%). Patients from long-term care were older, (87 vs. 84 years, p < 0.001), more had American Society of Anaesthesiologists (ASA) score >/= 3 (67% vs. 48%, p < 0.001) and a higher number of chronic medical conditions (mean 2.2 vs. 1.6, p < 0.001). Among community-dwelling patients, those who had fallen indoors were older, more often female, had ASA score >/= 3, chronic medical conditions, impairment in pre-fracture ADL and cognitive function, and more complications during hospital stay. CONCLUSIONS: Older hip fracture patients in this orthogeriatric unit may be divided into three groups; patients who are relatively fit and have experienced outdoors falls (17%), frail community-dwelling patients who have fallen indoors (59%), and patients from long-term care institutions (24%). Different caring pathways are needed for these groups

Shoulder instability surgery in Norway: The first report from a multicenter register, with 1-year follow-up

Background and purpose. In January 2008, we established the Norwegian Register for Shoulder Instability Surgery. We report on the establishment, the baseline data, and the results at 1-year follow-up. Methods. Primary and revision shoulder stabilization is reported by the surgeon on a 1-page paper form containing the patient's history of shoulder injury, clinical findings, and perioperative findings. The WOSI questionnaire for self-assessment of shoulder function is completed at baseline and at follow-up after 1, 2, and 5 years. To evaluate the completeness of registration, we compared our data with those in the Norwegian Patient Registry (NPR). Results. The NPR reported 39 hospitals performing shoulder stabilizations. 20 of these started to report to our register during 2009, and 464 procedures (404 primary, 59 revisions) were included up to December 31, 2009, which represented 54% of the procedures reported to NPR. Of the 404 primary procedures, 83% were operations due to anterior instability, 10% were operations due to posterior instability, and 7% were operations due to multidirectional instability. Arthroscopic soft tissue techniques were used in 88% of the patients treated for primary anterior instability and open coracoid transfer was used in 10% of such patients. At 1-year follow-up of 213 patients, we found a statistically significantly improved WOSI score in all types of instability. 10% of the patients treated with arthroscopic anterior labral repair and 16% treated with arthroscopic posterior labral repair reported recurrent instability. No statistically significant difference in functional improvement or rate of recurrence was found between these groups. Interpretation. The functional results are in accordance with those in previous studies. However, the incidence of recurrent instability 1 year after arthroscopic labral repair is higher than expected.publishedVersio

Modeling Dyslexic Students’ Motivation for Enhanced Learning in E-learning Systems

E-Learning systems can support real-time monitoring of learners’ learning desires and effects, thus offering opportunities for enhanced personalized learning. Recognition of the determinants of dyslexic users’ motivation to use e-learning systems is important to help developers improve the design of e-learning systems and educators direct their efforts to relevant factors to enhance dyslexic students’ motivation. Existing research has rarely attempted to model dyslexic users’ motivation in e-learning context from a comprehensive perspective. The present work has conceived a hybrid approach, namely, combining the strengths of qualitative and quantitative analysis methods, to motivation modeling. It examines a variety of factors that affect dyslexic students’ motivation to engage in e-learning systems from psychological, behavioral, and technical perspectives, and establishes their interrelationships. Specifically, the study collects data from a multi-item Likert-style questionnaire to measure relevant factors for conceptual motivation modeling. It then applies both covariance-based (CB-SEM) and variance-based structural equation modeling (PLS-SEM) approaches to determine the quantitative mapping between dyslexic students’ continued use intention and motivational factors, followed by discussions about theoretical findings and design instructions according to our motivation model. Our research has led to a novel motivation model with new constructs of Learning Experience, Reading Experience, Perceived Control, and Perceived Privacy. From both the CB-SEM and PLS-SEM analyses, results on the total effects have indicated consistently that Visual Attractiveness, Reading Experience, and Feedback have the strongest effects on continued use intentio

Anodic dissolution of metals in oxide-free cryolite melts

The anodic behavior of metals in molten cryolite-alumina melts has been investigated mostly for use as inert anodes for the Hall-Héroult process. In the present work, gold, platinum, palladium, copper, tungsten, nickel, cobalt and iron metal electrodes were anodically polarized in an oxide-free cryolite melt (11%wt. excess AlF3 ; 5%wt. CaF2) at 1273 K. The aim of the experiments was to characterize the oxidation reactions of the metals occurring without the effect of oxygen-containing dissolved species. The anodic dissolution of each metal was demonstrated, and electrochemical reactions were assigned using reversible potential calculation. The relative stability of metals as well as the possibility of generating pure fluorine is discussed

The period and amplitude changes in the coolest GW Virginis variable star (PG 1159-type) PG 0122+200

Context: The PG 1159 pre-white dwarf stars experiment a rapidly cooling phase with a time scale of a few 10 6 years. Theoretical models predict that the neutrinos produced in their core should play a dominant role in the cooling, mainly at the cool end of the PG 1159 sequence. Measuring the evolutionary time scale of the coolest PG 1159 stars could offer a unique opportunity to empirically constrain the neutrino emission rate. Aims. A subgroup of the PG 1159 stars are nonradial pulsators, the GW Vir type of variable stars. They exhibit g-mode pulsations with periods of a few hundred seconds. As the stars cool, the pulsation frequencies evolve according to the change in their internal structure. It was anticipated that the measurement of their rate of change would directly determine the evolution time scale and so constrain the neutrino emission rates. As PG 0122+200 (BB Psc) defines the red edge of the GW Vir instability strip, it is a good candidate for such a measurement. Methods. The pulsations of PG 0122+200 have been observed during 22 years from 1986 to 2008, through the fast photometry technique. We used those data to measure the rate of change of its frequencies and amplitudes. Results. Among the 24 identified ℓ = 1 modes, the frequency and amplitude variations have been obtained for the seven largest amplitude ones. We find changes of their frequency of much larger amplitudes and shorter time scales than the one predicted by theoretical models that assume that the cooling dominates the frequency variations. In the case of the largest amplitude mode at 2497 μHz (400 s), its variations are best fitted by a combination of two terms: one long term with a time scale of 5.4 × 10 4 years, which is significantly shorter than the predicted evolutionary time scale of 8 × 10 6 years; and one additional periodic term with a period of either 261 or 211 days. Some other mechanism(s) than the cooling must be responsible for such variations. We suggest that the resonant coupling induced within triplets by the star rotation could be such a mechanism. As a consequence, no useful constraints on the neutrino emission rate can presently be derived as long as the dominant mechanism is not properly understood. Conclusions. The temporal variations in the pulsation frequencies observed in PG 0122+200 cannot be simply attributed to the cooling of the star, regardless of the contribution of the neutrino losses. Our results suggest that the resonant coupling induced by the rotation plays a dominant role which must be further investigated.Facultad de Ciencias Astronómicas y Geofísica

Biological effects of rinsing morsellised bone grafts before and after impaction

Rinsing bone grafts before or both before and after impaction might have different effects on the incorporation of the graft. Rinsing again after impaction might negatively influence bone induction if growth factors released by impaction are washed away. We studied if transforming growth factor-βs (TGF-βs) and bone morphogenetic proteins (BMPs) are released from the mineralised matrix by impaction and if these released growth factors induce osteogenic differentiation in human mesenchymal stem cells (hMSCs). Rinsed morsellised bone allografts were impacted in a cylinder and the escaping fluid was collected. The fluid was analysed for the presence of TGF-βs and BMPs, and the osteoinductive capacity was tested on hMSCs. Abundant TGF-β was present in the fluid. No BMPs could be detected. Osteogenic differentiation of hMSCs was inhibited by the fluid. Results from our study leave us only able to speculate whether rinsing grafts again after impaction has a beneficial effect on the incorporation process or not

Multiwavelength observations revealing the outbursts of the two soft X-ray transients XTE J1859+226 and XTE J1118+480

We report here on multiwavelength observations of the two new soft X-ray transients (SXTs) XTE J1859+226 and XTE J1118+480, which we observed with HST/RXTE/UKIRT. For XTE J1118+480 we also used EUVE since it is located at a very high galactic latitude and suffers from very low extinction. The two sources exhibited very different behaviour. XTE J1859+226 seems quite normal and therefore a good object for testing the accretion mechanisms in place during the outbursts, XTE J1118+480 is much more unusual because it exhibits i) a low X-ray to optical ratio and ii) a strong non-thermal contribution in the radio to optical domain, which is likely to be due to synchrotron emission. We concentrate here on the near-infrared (NIR) and optical observations of these two systems.Comment: 4 pages, 6 figures, conference, Proceedings of the 4th INTEGRAL Workshop (Alicante 2000), to be published in ESA-SP (2001

The Structure and Evolution of Circumbinary Disks in Cataclysmic Variable Systems

We investigate the structure and evolution of a geometrically thin viscous Keplerian circumbinary (CB) disk, using detailed models of their radiative/convective vertical structure. We use a simplified description for the evolution of the cataclysmic binary and focus on cases where the circumbinary disk causes accelerated mass transfer (> 1e-8 Msun/yr). The inner edge of the disk is assumed to be determined by the tidal truncation radius and the mass input rate into the disk is assumed to be a small fraction (1e-5-0.01) of the mass transfer rate. Under the action of the viscous stresses in the disk the matter drifts outward with the optically thick region extending to several AU. The inner part of the disk is cool with maximum effective temperatures < 3,000 K while the outermost parts of the disk are < 30 K and optically thin. We calculate the effects of thermal instability on a sufficiently massive CB disk. It leads to outbursts reminiscent of those in thermally unstable accretion disks, with the instability remaining confined to the inner regions of the CB disk. However, for most of the evolutionary sequences the surface densities required to trigger instability are not reached. The spectral energy distributions from circumbinary disks are calculated, and the prospects for the detection of such disks in the infrared and submm wavelength regions are discussed.Comment: 16 pages, 12 figures, accepted for publication by Ap

Geometrical Constraints on Dark Energy

We explore the recently introduced statefinder parameters. After reviewing their basic properties, we calculate the statefinder parameters for a variety of cosmological models, and investigate their usefulness as a means of theoretical classification of dark energy models. We then go on to consider their use in obtaining constraints on dark energy from present and future supernovae type Ia data sets. Provided that the statefinder parameters can be extracted unambiguously from the data, they give a good visual impression of where the correct model should lie. However, it is non-trivial to extract the statefinders from the data in a model-independent way, and one of our results indicates that an expansion of the dark energy density to second order in the redshift is inadequate. Hence, while a useful theoretical and visual tool, applying the statefinders to observations is not straightforward.Comment: v2, 14 pages, 18 figures. Added references, better figures. Submitted to A&