Non-invasive computer-assisted measurement of knee alignment

The quantification of knee alignment is a routine part of orthopaedic practice and is important for monitoring disease progression, planning interventional strategies, and follow-up of patients. Currently available technologies such as radiographic measurements have a number of drawbacks. The aim of this study was to validate a potentially improved technique for measuring knee alignment under different conditions. An image-free navigation system was adapted for non-invasive use through the development of external infrared tracker mountings. Stability was assessed by comparing the variance (F-test) of repeated mechanical femoro-tibial (MFT) angle measurements for a volunteer and a leg model. MFT angles were then measured supine, standing and with varus-valgus stress in asymptomatic volunteers who each underwent two separate registrations and repeated measurements for each condition. The mean difference and 95% limits of agreement were used to assess intra-registration and inter-registration repeatability. For multiple registrations the range of measurements for the external mountings was 1° larger than for the rigid model with statistically similar variance (p=0.34). Thirty volunteers were assessed (19 males, 11 females) with a mean age of 41 years (range: 20-65) and a mean BMI of 26 (range: 19-34). For intra-registration repeatability, consecutive coronal alignment readings agreed to almost ±1°, with up to ±0.5° loss of repeatability for coronal alignment measured before and after stress maneuvers, and a ±0.2° loss following stance trials. Sagittal alignment measurements were less repeatable overall by an approximate factor of two. Inter-registration agreement limits for coronal and sagittal supine MFT angles were ±1.6° and ±2.3°, respectively. Varus and valgus stress measurements agreed to within ±1.3° and ±1.1°, respectively. Agreement limits for standing MFT angles were ±2.9° (coronal) and ±5.0° (sagittal), which may have reflected a variation in stance between measurements. The system provided repeatable, real-time measurements of coronal and sagittal knee alignment under a number of dynamic, real-time conditions, offering a potential alternative to radiographs

806-1 Left Ventricular Ejection Fraction After Myocardial Infarction: Importance of Both Infarct Site and Size

Left ventricular ejection fraction (LVEF) is an important prognostic variable after myocardial infarction (MI). While the extent of MI is known to affect the subsequent global LVEF, it is not clear whether anatomical site per se affects LVEF. Therefore, 48 consecutive patients (pts) who did not receive lytic therapy or undergo early revascularization were studied byechocardiography one week after Q wave MI. Using a previously validated endocardial mapping technique, the size of abnormal wall motion (AWM) in relation to the total endocardial surface area and the site of AWM were quantitated, LVEF was measured by Simpson's method using 2 apical views.ResultsNineteen pts had anterior MI (ANT) and 29 had inferior MI (INF). The mean LVEF was similar in both groups (ANT 46.9±14.7% vs INF 51.7±9.4%, pNS). The mean %AWM was greater in ANT MI (29.7±14.5) than in INF MI (21.3±13.8) (p=0.05). After accounting for differences in infarct size by multivariate regression analysis, both infarct size (p=0.0001) and infarct site (p=0.007) were significant independent determinants of LVEF. This effect was most pronounced in larger ANT Mis (%AWM>25%) where the LVEF was significantly lower than in smaller Mis. In INF MI, despite a similar range of sizes. increasing %AWM had minimal effect on LVEF.ConclusionIn addition to infarct size, the site of AWM is an important determinant of global LVEF. This observation may reflect site-dependent differences in the biomechanical responses to regional ventricular dysfunction

Global embedding of the Kerr black hole event horizon into hyperbolic 3-space

An explicit global and unique isometric embedding into hyperbolic 3-space, H^3, of an axi-symmetric 2-surface with Gaussian curvature bounded below is given. In particular, this allows the embedding into H^3 of surfaces of revolution having negative, but finite, Gaussian curvature at smooth fixed points of the U(1) isometry. As an example, we exhibit the global embedding of the Kerr-Newman event horizon into H^3, for arbitrary values of the angular momentum. For this example, considering a quotient of H^3 by the Picard group, we show that the hyperbolic embedding fits in a fundamental domain of the group up to a slightly larger value of the angular momentum than the limit for which a global embedding into Euclidean 3-space is possible. An embedding of the double-Kerr event horizon is also presented, as an example of an embedding which cannot be made global.Comment: 16 pages, 13 figure

On finite-time ruin probabilities for classical risk models

info:eu-repo/semantics/publishe

La transfrontalièrité : le cas de la Turquie

Difficile à classer, la Turquie est à la fois un pays européen, balkanique, moyen-oriental, asiatique et méditerranéen, avec une façade importante sur la "mer nourricière". Elle porte en elle-même toute la diversité et les contradictions de ces aires auxquelles elle appartient géographiquement et culturellement. Elle est attirée, depuis plus d'un siècle, par trois pôles de "civilisation"; par l'Asie centrale, par ses liens culturels, affectifs et linguistiques; par le monde arabe, par ses att..

Hydrology, Water Chemistry, and Vegetation Characteristics of a Tamarack Bog in Bath Township, Ohio: Towards Restoration and Enhancement

Author Institution: Dept. of Biology, University of Akron, OHAuthor Institution: Dept. of Botany, University of British Columbia, Vancouver, BC, CanadaAuthor Institution: Dept. of Natural Resource Science, Thompson Rivers University, Kamloops, BC, CanadaThe current state of the Bath Tamarack Bog has raised concern about the health and function of the system. Only 6 tamarack (Larix laricina) trees remain, while deciduous trees, particularly red maple (Acer rubrum) and invasive species such as glossy buckthorn (Rhamnus frangula) and multiflora rose (Rosa multiflora), dominate the bog. Our purpose was to assess the physical, chemical, and biological properties of the tamarack bog. Environmental and biological properties of Bath Tamarack Bog were measured from May 2001 through November 2002. In 2001, the center of the bog experienced water levels below those typically found in bogs, yet experienced normal water levels in the following year. Water chemistry results indicate the pH is much greater than that characteristic of a typical bog, ranging from 5.94 to 7.41. Nutrient levels fluctuated and were generally higher for calcium, potassium, and phosphate than a typical bog, while nitrogen levels remained low. These results indicate that the bog is not functioning normally and is in decline. The degradation of the bog is most likely due to anthropogenic activity. Ditching occurred between 1963 and 1969 and seems to have induced the progression of red maple trees and invasive species into the bog by lowering water levels. Since 1938, the first aerial photo we have record of, the bog has reduced to approximately a third of its size, which is approximately 1.99 hectares. The bog appears to be in a late successional stage, rapidly changing to a forested wetland. We discuss possible management and restoration efforts needed to restore or enhance the tamarack bog, including 1) planting Sphagnum mats, 2) introducing tamarack seedlings, 3) controlling invasive species, and 4) maintaining the hydrology close to the soil surface. All of these measures are suggested in association with educational outreach

Interleukin (IL)–12 and IL-23 Are Key Cytokines for Immunity against Salmonella in Humans

Patients with inherited deficiency of the interleukin (IL)–12/IL-23–interferon (IFN)–g axis show increased susceptibility to invasive disease caused by the intramacrophage pathogens salmonellae and mycobacteria. We analyzed data on 154 patients with such deficiency. Significantly more patients with IL-12/IL-23–component deficiency had a history of salmonella disease than did those with IFN-g–component deficiency. Salmonella disease was typically severe, extraintestinal, and caused by nontyphoidal serovars. These findings strongly suggest that IL-12/IL-23 is a key cytokine for immunity against salmonella in humans and that IL-12/IL-23 mediates this protective effect partly through IFN-g–independent pathways. Investigation of the IL-12/IL-23–IFN-g axis should be considered in patients with invasive salmonella disease

HST-NICMOS Observations of Terzan 5: Stellar Content and Structure of the Core

We report results from HST-NICMOS imaging of the extremely dense core of the globular cluster Terzan 5. This highly obscured bulge cluster has been estimated to have one of the highest collision rates of any galactic globular cluster, making its core a particularly conducive environment for the production of interacting binary systems. We have reconstructed high-resolution images of the central 19"x19" region of Terzan 5 by application of the drizzle algorithm to dithered NIC2 images in the F110W, F187W, and F187N near-infrared filters. We have used a DAOPHOT/ALLSTAR analysis of these images to produce the deepest color-magnitude diagram (CMD) yet obtained for the core of Terzan 5. We have also analyzed the parallel 11"X11" NIC1 field, centered 30" from the cluster center and imaged in F110W and F160W, and an additional NIC2 field that is immediately adjacent to the central field. This imaging results in a clean detection of the red-giant branch and horizontal branch in the central NIC2 field, and the detection of these plus the main-sequence turnoff and the upper main sequence in the NIC1 field. We have constructed an H versus J-H CMD for the NIC1 field. We obtain a new distance estimate of 8.7 kpc, which places Terzan 5 within less than 1 kpc of the galactic center. We have also determined a central surface-density profile which results in a maximum likelihood estimate of 7.9" +/- 0.6" for the cluster core radius. We discuss the implications of these results for the dynamical state of Terzan 5.Comment: 17 pages, 9 figures, accepted for publication in ApJ, for May 20, 200