43 research outputs found
Pilot study: Performance-ranking relationship analysis in Czech crossfiters
CrossFit is one of the fastest growing sports. Its growing popularity also applies to its competition form. This pilot study aims to analyse strength, endurance performance and their relationship to the resulting ranking in the CrossFit Open. Furthermore, the forms of training of elite Czech crossfitters are described in more detail. The research sample consisted of the 20 best Czechs (average height, age, and bodyweight of 180cm, 28.5 years and 90.7 kg respectively) according to the CrossFit Open ranking. The questionnaire was used to collect information regarding the training regime and their current performance parameters. Descriptive statistics include the correlation between individual performances and overall ranking. Crossfitters had very good strength parameters in exercises with external load and also with their bodyweight (average values: clean and jerk 141.5 kg, snatch 113.9 kg, back squat 184.1 kg, strict press 87.2 kg, deadlift 217.9 kg, strict handstand push-ups 21.5 reps., pull-ups 20.6 reps.). The Olympic weightlifting performance (snatch and clean and jerk) was the strongest predictor for placing (-.606 resp. -.625, α=.01). The weekly training time was 800-900 minutes and contained mostly combined training units with a total of 9.2. Given the interesting results achieved in this pilot study, more detailed and validated studies are needed.The support of the Specific research project of FIM UHK for the year 2020 is gratefully acknowledged
Genetic testing for inherited retinal degenerations: Triumphs and tribulations
Inherited retinal degenerations (IRDs) are a genotypically and phenotypically diverse group of conditions. Great strides have been made toward identifying the genetic basis for these conditions over the last 30 years—more than 270 different genes involved in syndromic and nonsyndromic forms of retinal dystrophies have now been identified. The identification of these genes and the improvement of clinical laboratory techniques have led to the identification of the genetic basis of disease in 56–76% of patients with IRDs through next generation sequencing and copy number variant analysis. Genetic testing is an essential part of clinical care for patients affected with IRDs and is required to confirm the diagnosis, understand the inheritance of the condition, and determine eligibility for gene‐specific treatments or clinical trials. Despite the success achieved in determining the genetic cause of these conditions, several challenges remain, which must be considered when providing genetic testing and genetic counseling to patients. For this reason, an integrated team of ophthalmic and genetic clinicians who are familiar with these challenges is necessary to provide optimal comprehensive care to these patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162692/2/ajmgc31835.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162692/1/ajmgc31835_am.pd
Contrast sensitivity deficits in patients with mutation-proven inherited retinal degenerations
Abstract
Background
Patients with retinal diseases frequently complain of poor visual function even when visual acuity is relatively unaffected. This clinical finding has been attributed to deficits in contrast sensitivity (CS). The purpose of our study was to evaluate the CS in patients with clinical and genetic diagnosis of inherited retinal degeneration (IRD) and relatively preserved visual acuity.
Methods
Seventeen patients (30 eyes) with IRD and visual acuity of 20/40 or better, and 18 controls (18 eyes) without any ocular condition underwent slit lamp examination, visual acuity testing via standard Snellen chart testing, CS testing via the Quick Contrast Sensitivity Function (QCSF), and Spectral Domain Optical Coherence Tomography (SD-OCT). CS were measured at 1.0, 1.5, 3.0, 6.0, 12.0, and 18.0 cycles per degree (cpd). T tests with general estimated equations were used to compare CS between groups. Wald chi square followed by pairwise comparisons was used to compare CS between multiple groups.
Results
We included 12 patients with rod-cone dystrophy (RCD), 3 patients with Stargardt disease (STGD) and 2 patients with Best disease. Patients with IRD had significantly worse CS than controls (p < 0.001) in all spatial frequencies. Patients with STGD had more marked deficits in CS than patients with Best disease (p < 0.001) and RCD (p < 0.001) despite having similar visual acuities.
Conclusion
Patients with IRD, especially patients with STGD with relatively preserved visual acuity have marked deficits in CS when measured across a range of spatial frequencies. We recommend that clinical trials for STGD incorporate CS measured over a range of spatial frequencies as a secondary clinical endpoint for monitoring visual function. CS may provide an explanation for complaints of visual dysfunction when visual acuity is not significantly altered.https://deepblue.lib.umich.edu/bitstream/2027.42/146723/1/12886_2018_Article_982.pd
Macular hyperpigmentary changes in ABCA4-Stargardt disease
Abstract
Background
Stargardt disease (STGD) and age-related macular degeneration (AMD) share clinical and pathophysiological features. In AMD, macular hyperpigmentary changes are associated to a worse prognosis. The purpose of this study was to characterize macular hyperpigmentary changes in patients with STGD and associate them with the severity of phenotype.
Materials and methods
This retrospective cross-sectional study included 141 patients with STGD. Hyperpigmentary changes were evaluated on color fundus photography and spectral-domain optical coherence tomography. Severity of phenotype was assessed by full-field electroretinogram (ffERG) and fundus autofluorescence (FAF) patterns, and visual acuity (VA).
Results
Thirty patients (21.7%) showed macular hyperpigmentary changes in four distinct patterns. Out of seventeen patients who had follow-up images, eleven patients demonstrated increases of the hyperpigmented lesions, and progression of the underlying RPE atrophy overtime. VA remained stable. Of 28 patients who had ffERG, 17 patients presented with reduction of photopic and scotopic responses, while 8 presented with reduction of photopic responses only, and 3 presented with preserved photopic and scotopic responses. Of 25 patients who had FAF available, 12 presented with widespread disease extending anteriorly to the vascular arcades, while eight presented with widespread disease, extending beyond the vascular arcades, and 5 presented with disease confined to the foveal area.
Conclusion
In this study, we demonstrated that patients with STGD with macular hyperpigmented lesions had a severe phenotype. Overtime, hyperpigmented lesions increased in size, spread across the retina, and migrated to different retinal layers. Macular hyperpigmentation may be a marker of advanced stage of the disease.https://deepblue.lib.umich.edu/bitstream/2027.42/148528/1/40942_2019_Article_160.pd
Proper Motions in Kapteyn Selected Area 103: A Preliminary Orbit for the Virgo Stellar Stream
We present absolute proper motions in Kapteyn Selected Area (SA) 103. This
field is located 7 degrees west of the center of the Virgo Stellar Stream (VSS,
Duffau et al. 2006), and has a well-defined main sequence representing the
stream. In SA 103 we identify one RR Lyrae star as a member of the VSS
according to its metallicity, radial velocity and distance. VSS candidate
turnoff stars and subgiant stars have proper motions consistent with that of
the RR Lyrae star. The 3D velocity data imply an orbit with a pericenter of 11
kpc and an apocenter of ~90 kpc. Thus, the VSS comprises tidal debris found
near the pericenter of a highly destructive orbit. Examining the six globular
clusters at distances larger than 50 kpc from the Galactic center, and the
proposed orbit of the VSS, we find one tentative association, NGC 2419. We
speculate that NGC 2419 is possibly the nucleus of a disrupted system of which
the VSS is a part.Comment: ApJL accepte
The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey
The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic
data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data
release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median
z=0.52), 102,100 new quasar spectra (median z=2.32), and 90,897 new stellar
spectra, along with the data presented in previous data releases. These spectra
were obtained with the new BOSS spectrograph and were taken between 2009
December and 2011 July. In addition, the stellar parameters pipeline, which
determines radial velocities, surface temperatures, surface gravities, and
metallicities of stars, has been updated and refined with improvements in
temperature estimates for stars with T_eff<5000 K and in metallicity estimates
for stars with [Fe/H]>-0.5. DR9 includes new stellar parameters for all stars
presented in DR8, including stars from SDSS-I and II, as well as those observed
as part of the SDSS-III Sloan Extension for Galactic Understanding and
Exploration-2 (SEGUE-2).
The astrometry error introduced in the DR8 imaging catalogs has been
corrected in the DR9 data products. The next data release for SDSS-III will be
in Summer 2013, which will present the first data from the Apache Point
Observatory Galactic Evolution Experiment (APOGEE) along with another year of
data from BOSS, followed by the final SDSS-III data release in December 2014.Comment: 9 figures; 2 tables. Submitted to ApJS. DR9 is available at
http://www.sdss3.org/dr
The Origin of the Virgo Stellar Substructure
We present three-dimensional space velocities of stars selected to be
consistent with membership in the Virgo stellar substructure. Candidates were
selected from SA 103, a single 40x40 arcmin field from our proper motion (PM)
survey in Kapteyn's Selected Areas (SAs), based on the PMs, SDSS photometry,
and follow-up spectroscopy of 215 stars. The signature of the Virgo
substructure is clear in the SDSS color-magnitude diagram (CMD) centered on SA
103, and 16 stars are identified that have high Galactocentric-frame radial
velocities (V_GSR > 50 km/s) and lie near the CMD locus of Virgo. The implied
distance to the Virgo substructure from the candidates is 14+/-3 kpc. We derive
mean kinematics from these 16 stars, finding a radial velocity V_GSR = 153+/-22
km/s and proper motions (mu_alpha*cos(delta), mu_delta) = (-5.24,
-0.91)+/-(0.43, 0.46) mas/yr. From the mean kinematics of these members, we
determine that the Virgo progenitor was on an eccentric (e ~ 0.8) orbit that
recently passed near the Galactic center (pericentric distance R_p ~ 6 kpc).
This destructive orbit is consistent with the idea that the substructure(s) in
Virgo originated in the tidal disruption of a Milky Way satellite. N-body
simulations suggest that the entire cloud-like Virgo substructure (encompassing
the "Virgo Overdensity" and the "Virgo Stellar Stream") is likely the tidal
debris remnant from a recently-disrupted massive (~10^9 M_sun) dwarf galaxy.
The model also suggests that some other known stellar overdensities in the
Milky Way halo (e.g., the Pisces Overdensity and debris near NGC 2419 and SEGUE
1) are explained by the disruption of the Virgo progenitor.Comment: Accepted to ApJ; preprint format, 41 pages, 17 figures (some with
degraded resolution). Full-resolution version (in emulateapj format)
available at
http://homepages.rpi.edu/~carlij/virgo_paper/carlin_etal2012_virgo.pd
Kinematics and Chemistry of Stars Along the Sagittarius Trailing Tidal Tail and Constraints on the Milky Way Mass Distribution
We present three-dimensional kinematics of Sagittarius (Sgr) trailing tidal
debris in six fields located 70-130 degrees along the stream from the Sgr dwarf
galaxy core. The data are from our proper-motion (PM) survey of Kapteyn's
Selected Areas, in which we have measured accurate PMs to faint magnitudes in
40x40 arcmin fields evenly spaced across the sky. The radial velocity (RV)
signature of Sgr has been identified among our follow-up spectroscopic data in
four of the six fields and combined with mean PMs of
spectroscopically-confirmed members to derive space motions of Sgr debris based
on 15-64 confirmed stream members per field. These kinematics are compared to
predictions of the Law & Majewski (2010) model of Sgr disruption; we find
reasonable agreement with model predictions in RVs and PMs along Galactic
latitude. However, an upward adjustment of the Local Standard of Rest velocity
Theta_LSR from its standard 220 km/s to at least km/s (and possibly
as high as km/s) is necessary to bring 3-D model debris kinematics
and our measurements into agreement. Satisfactory model fits that
simultaneously reproduce known position, distance, and radial velocity trends
of the Sgr tidal streams, while significantly increasing Theta_LSR}, could only
be achieved by increasing the Galactic bulge and disk mass while leaving the
dark matter halo fixed to the best-fit values from Law & Majewski (2010). We
derive low-resolution spectroscopic abundances along this stretch of the Sgr
stream and find a constant [Fe/H] = -1.15 (with ~0.5 dex scatter in each field
-- typical for dwarf galaxy populations) among the four fields with reliable
measurements. A constant metallicity suggests that debris along the ~60-degree
span of this study was all stripped from Sgr on the same orbital passage.Comment: 26 pages, 24 figures (some with degraded resolution), accepted to
ApJ; full-resolution version available at
http://www.rpi.edu/~carlij/sgr_paper/ms.apjformat.ps.g