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Search Results: 1 - 10 of 342798 matches for " James S. Wrobel "
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James S. Wrobel,Samuel Marclay,Bijan Najafi
Journal of Sports Science and Medicine , 2012,
Abstract: Golfers have better balance than their age-matched counterparts; however, it is uncertain if this persists during the swing as a function of skill level. The purpose of the study was to investigate dynamic postural control (center of mass (COM) motion) measured during different phases of the swing in golfers of varying proficiency. Eighteen healthy golfers were grouped by handicap: novice (no handicap, n = 7), intermediate (handicap 15-19, n = 7), and advanced (handicap 9-14, n = 4). Indoor testing was performed hitting 3 tee shots using a common driver. A five-camera (60 Hz) motion analysis system (9 markers) was used to extract kinematics data. There were no significant group differences in gender, age, or BMI. Advanced players had lower COM displacement with respect to address at the time of maximum arm speed (p = 0. 001) compared to intermediate (57%, p = 0.014) and novice (73%, p = 0.023). These changes persisted after COM distance and time normalization. Advanced golfers had improved COM linearity during the downswing (p < 0.001) compared to intermediate (30%, p = 0.029) and novice (51%, p < 0.001). Advanced players had decreased COM displacement at the time of maximum arm speed and a more linear COM path during the early downswing. Further study should focus on these changes during ball launch conditions
Clinical factors associated with a conservative gait pattern in older male veterans with diabetes
James S Wrobel, Ryan T Crews, John E Connolly
Journal of Foot and Ankle Research , 2009, DOI: 10.1186/1757-1146-2-11
Abstract: Male veterans (mean age = 67 years; SD = 9.8; range 37–86) with diabetes (n = 152) participated in this study from July 2000 to May 2001 at the Veterans Affairs Medical Center, White River Junction, VT. Various demographic, clinical, static mobility, and plantar pressure measures were collected. Conservative gait pattern was defined by visual gait analysis as failure to demonstrate a heel-to-toe gait during the propulsive phase of gait.Patients with the conservative gait pattern had lower walking speed and decreased stride length compared to normal gait. (0.68 m/s v. 0.91 m/s, p < 0.001; 1.04 m v. 1.24 m, p < 0.001) Age, monofilament insensitivity, and Romberg's sign were significantly higher; and ankle dorsiflexion was significantly lower in the conservative gait pattern group. In the multivariate analysis, walking speed, age, ankle dorsiflexion, and callus were retained in the final model describing 36% of the variance. With the inclusion of ankle dorsiflexion in the model, monofilament insensitivity was no longer an independent predictor.Our multivariate investigation of conservative gait in diabetes patients suggests that walking speed, advanced age, limited ankle dorsiflexion, and callus describe this condition more so than clinical measures of neuropathy.Gait alteration in patients with diabetes has been described [1-3]. Patients with diabetes and peripheral neuropathy (DMPN) exhibit gait instability [4,5]. While this may appear trivial to the treating clinician, unsteadiness in gait demonstrated the strongest association with depressive symptoms in a study by Vileikyte and colleagues [6]. Chamberlin and colleagues identified fearful walkers from a Modified Falls Efficacy Scale. They found fearful walkers demonstrated a slower walking speed, shorter stride length, and longer double support time than walkers not identified as fearful [7]. Courtemanche and colleagues observed similar findings in DMPN patients. They found prolonged reaction times leading the auth
Retinal Spectral Domain Optical Coherence Tomography in Early Atrophic Age-Related Macular Degeneration (AMD) and a New Metric for Objective Evaluation of the Efficacy of Ocular Nutrition
Stuart Richer,Jane Cho,William Stiles,Marc Levin,James S. Wrobel,Michael Sinai,Carla Thomas
Nutrients , 2012, DOI: 10.3390/nu4121812
Abstract: Purpose: A challenge in ocular preventive medicine is identification of patients with early pathological retinal damage that might benefit from nutritional intervention. The purpose of this study is to evaluate retinal thinning (RT) in early atrophic age-related macular degeneration (AMD) against visual function data from the Zeaxanthin and Visual Function (ZVF) randomized double masked placebo controlled clinical trial (FDA IND #78973). Methods: Retrospective, observational case series of medical center veterans with minimal visible AMD retinopathy (AREDS Report #18 simplified grading 1.4/4.0 bilateral retinopathy). Foveal and extra-foveal four quadrant SDOCT RT measurements were evaluated in n = 54 clinical and ZVF AMD patients. RT by age was determined and compared to the OptoVue SD OCT normative database. RT by quadrant in a subset of n = 29 ZVF patients was correlated with contrast sensitivity and parafoveal blue cone increment thresholds. Results: Foveal RT in AMD patients and non-AMD patients was preserved with age. Extrafoveal regions, however, showed significant slope differences between AMD patients and non-AMD patients, with the superior and nasal quadrants most vulnerable to retinal thinning (sup quad: ?5.5 μm/decade thinning vs. Non-AMD: ?1.1 μm/decade, P < 0.02; nasal quad: ?5.0 μm/decade thinning vs. Non-AMD: ?1.0 μm/decade, P < 0.04). Two measures of extrafoveal visual deterioration were correlated: A significant inverse correlation between % RT and contrast sensitivity ( r = ?0.33, P = 0.01, 2 Tailed Paired T) and an elevated extrafoveal increment blue cone threshold ( r = +0.34, P = 0.01, 2 Tailed T). Additional SD OCT RT data for the non-AMD oldest age group (ages 82–91) is needed to fully substantiate the model. Conclusion: A simple new SD OCT clinical metric called “% extra-foveal RT” correlates well with functional visual loss in early AMD patients having minimal visible retinopathy. This metric can be used to follow the effect of repleting ocular nutrients, such as zinc, antioxidants, carotenoids, n-3 essential fats, resveratrol and vitamin D.
Plantar Temperature Response to Walking in Diabetes with and without Acute Charcot: The Charcot Activity Response Test
Bijan Najafi,James S. Wrobel,Gurtej Grewal,Robert A. Menzies,Talal K. Talal,Mahmoud Zirie,David G. Armstrong
Journal of Aging Research , 2012, DOI: 10.1155/2012/140968
Abstract: Objective. Asymmetric plantar temperature differences secondary to inflammation is a hallmark for the diagnosis and treatment response of Charcot foot syndrome. However, little attention has been given to temperature response to activity. We examined dynamic changes in plantar temperature (PT) as a function of graduated walking activity to quantify thermal responses during the first 200 steps. Methods. Fifteen individuals with Acute Charcot neuroarthropathy (CN) and 17 non-CN participants with type 2 diabetes and peripheral neuropathy were recruited. All participants walked for two predefined paths of 50 and 150 steps. A thermal image was acquired at baseline after acclimatization and immediately after each walking trial. The PT response as a function of number of steps was examined using a validated wearable sensor technology. The hot spot temperature was identified by the 95th percentile of measured temperature at each anatomical region (hind/mid/forefoot). Results. During initial activity, the PT was reduced in all participants, but the temperature drop for the nonaffected foot was 1.9 times greater than the affected side in CN group ( ?? = 0 . 0 4 ). Interestingly, the PT in CN was sharply increased after 50 steps for both feet, while no difference was observed in non-CN between 50 and 200 steps. Conclusions. The variability in thermal response to the graduated walking activity between Charcot and non-Charcot feet warrants future investigation to provide further insight into the correlation between thermal response and ulcer/Charcot development. This stress test may be helpful to differentiate CN and its response to treatment earlier in its course. 1. Background Charcot neuroarthropathy (CN) is a devastating complication of diabetes. It has a similar mortality rate as lower extremity ulceration and a twofold higher rate of major amputation compared to those without CN [1]. It has been estimated that 63% of CN patients will develop a foot ulcer [2]. The combination of foot ulcer and CN increases the risk of amputation 12-fold [3]. The increased mortality risk associated with CN appears to be independent of foot ulcer and other comorbidities [2]. What further complicates CN is that there is no clear definition for it [4]. There are no pathologic markers or diagnostic criteria. Therefore, the diagnosis relies on pattern recognition and clinical intuition [5]. Not surprisingly, the diagnosis can be missed up to 95% of the time [6] and the average diagnostic delay has been estimated at almost 7 months [7]. A significant number of CN patients either
Solution of hyperbolic bioheat transfer problems by numerical green's functions: the ExGA-linear θ method
Loureiro, F. S.;Wrobel, L. C.;Mansur, W. J.;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2012, DOI: 10.1590/S1678-58782012000400006
Abstract: this paper presents a time-domain formulation called explicit green's approach (exga) linear θ method for the solution of the bioheat equation. starting from the hyperbolic bioheat equation, which includes the parabolic one as a special case, the linear method is incorporated into the standard exga time marching scheme. the numerical green's function is firstly computed in the laplace transform domain and then back-transformed to the time domain through the stehfest inversion algorithm. the proposed formulation has the properties of stabilizing the results and suppressing numerical oscillations that appear in the presence of discontinuous solutions as assessed through the analysis of some bioheat transfer problems.
Radio Continuum Evidence for Outflow and Absorption in the Seyfert 1 Galaxy Markarian 231
J. S. Ulvestad,J. M. Wrobel,C. L. Carilli
Physics , 1999, DOI: 10.1086/307111
Abstract: The VLBA and the VLA have been used to image the continuum radio emission from Mrk 231, a Seyfert 1 galaxy and the brightest infrared galaxy in the local universe. The smallest scales reveal a double source less than 2 pc in extent. The components of this central source have minimum brightness temperatures of 10^9 to 10^{10} K, spectral turnovers between 2 and 10 GHz, and appear to define the galaxy nucleus plus the inner regions of a jet. The components may be free-free absorbed or synchtrotron self-absorbed. On larger scales, the images confirm a previously known north-south triple source extending 40 pc and elongated perpendicular to a 350-pc starburst disk. Both lobes show evidence for free-free absorption near 2 GHz, probably due to ionized gas with a density of 1-2 X 10^3 cm^{-3} in the innermost parts of the starburst disk. The absorbing gas may be ionized by the active nucleus or by local regions of enhanced star formation. The elongation of the 40-pc triple differs by 65 deg from that of the 2-pc source. The different symmetry axes on different scales imply strong curvature in the inner part of the radio jet. The radio continuum from the 350-pc disk has a spectral index near -0.4 above 1.4 GHz and is plausibly energized by a massive burst of star formation. On VLA scales, asymmetric and diffuse emission extends for more than 25 kpc. This emission has a steep spectrum, linear polarization exceeding 50% at some locations, and shares the symmetry axis of the 40-pc triple. The diffuse radio source is probably generated by energy deposition from a slow-moving nuclear jet, which conceivably could help energize the off-nuclear starburst as well.
A Sub-kpc Disk in MRK 231
C. L. Carilli,J. M. Wrobel,J. S. Ulvestad
Physics , 1997,
Abstract: We present imaging of the HI 21cm absorption line system seen toward the nuclear regions of Mrk 231 at z = 0.04217, and imaging of the radio continuum emission at 1.4 GHz, on scales ranging from a few parsecs to a few hundred parsecs. These data indicate the existence of a sub-kpc gas disk in Mrk 231, as seen in HI 21cm absorption and in radio continuum emission. The radio continuum morphology is consistent with a disk of maximum radius of 440 mas, at an inclination angle of 45deg, with a major axis oriented east-west. The HI 21cm absorption shows an east-west gradient in position and velocity of about +/-110 km/s out to radii of 100 mas. We identify this HI and radio continuum disk as the inner part of the molecular disk seen on a factor three larger scale. The physical conditions for the thermal and non-thermal gas in the sub-kpc disk of Mrk 231 are similar to those proposed for compact nuclear starburst galaxies, and in particular to the conditions proposed for the sub-kpc gas disk in Arp 220. From the neutral hydrogen velocity field we derive a gravitational mass enclosed within a 50 pc radius of 3x10**8 solar masses. We derive a massive star formation rate in the disk of 60 solar masses per year. We also present a search for HI 21cm absorption associated with the optical broad absorption line systems toward Mrk 231. We do not detect HI 21cm absorption associated with any of the optical BAL systems. These negative results require that the neutral atomic gas in the BAL clouds be fairly warm (T > 50 K), unless the NaI abundance is higher than solar, or the dust-to-gas ratio is higher than Galactic, or the observed extinction toward the nucleus of Mrk 231 is not due to the BAL gas.
Dale Towshend, The Orders of Gothic; Foucault, Lacan, and the Subject of Gothic Writing, 1764-1820
Claire Wrobel
Revue d’études Benthamiennes , 2010,
Abstract: Dans The Orders of Gothic, Dale Townshend propose une lecture conjointe de trois corpus : les écrits de Foucault, ceux de Lacan et la littérature gothique produite au Royaume Uni entre 1764 et 1820. 1764 correspond à la parution du Castle of Otranto de Horace Walpole, sous-titré A Gothick Story et qui contient un certain nombre de traits récurrents dans ces romans de la terreur, que l’on a également appelés romans noirs. Townshend s’intéresse donc au gothique canonique, celui qui s’achève...
Gothique, réforme et Panoptique
Claire Wrobel
Revue d’études Benthamiennes , 2010, DOI: 10.4000/etudes-benthamiennes.214
Abstract: IntroductionJamais construit, jamais occupé, le Panoptique de Bentham demeure une architecture virtuelle qu’il est possible d’interpréter, de rêver ou de cauchemarder avec peut-être plus de liberté que si elle s’était incarnée dans la pierre. Si d’un c té, des recherches récentes ont permis de préciser l’évolution historique de ce projet dans la pensée de Bentham, dans d’autres domaines, le Panoptique est un paradigme utilisé pour lire la littérature anglo-saxonne de la fin du XVIIIe sièc...
Reflection Scan: an Off-Path Attack on TCP
Jan Wrobel
Computer Science , 2012,
Abstract: The paper demonstrates how traffic load of a shared packet queue can be exploited as a side channel through which protected information leaks to an off-path attacker. The attacker sends to a victim a sequence of identical spoofed segments. The victim responds to each segment in the sequence (the sequence is reflected by the victim) if the segments satisfy a certain condition tested by the attacker. The responses do not reach the attacker directly, but induce extra load on a routing queue shared between the victim and the attacker. Increased processing time of packets traversing the queue reveal that the tested condition was true. The paper concentrates on the TCP, but the approach is generic and can be effective against other protocols that allow to construct requests which are conditionally answered by the victim. A proof of concept was created to assess applicability of the method in real-life scenarios.
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