Global Monitoring for Environment and Security (GMES) is the European programme to establish a European capacity for Earth Observation. GMES is designed to provide European policy makers and public ...authorities with accurate and timely information to better manage the environment, understand and mitigate the effects of climate change and ensure civil security. Sentinel-3 is an Earth observation satellite mission specifically designed for GMES to ensure the long-term collection and operational delivery of high-quality measurements to GMES ocean, land, and atmospheric services, while contributing to the GMES, emergency and security services. Key Sentinel-3 measurement requirements, corresponding to identified GMES user needs, have been derived as follows:•Sea surface topography (SSH), significant wave height (Hs) and surface wind speed derived over the global ocean to an equivalent accuracy and precision as that presently achieved by ENVISAT Radar Altimeter-2 (RA-2) but with enhanced surface topography measurements in the coastal zone, sea ice regions and over inland rivers, their tributaries and lakes.•Sea surface temperature (SST) determined for oceanic and coastal waters globally to an equivalent accuracy and precision as that presently achieved by the ENVISAT Advanced Along Track Scanning Radiometer (AATSR) over the ocean (i.e. <0.3K), at a spatial resolution of 1km.•Visible, and Short-Wave Infrared radiances for oceanic, inland and coastal waters at a spatial resolution of 0.3km (simultaneously and co-registered with SST measurements), determined to an equivalent level of accuracy and precision as ENVISAT Medium Resolution Imaging Spectrometer with complete ocean coverage in 2–3days.•Visible and infrared radiances over global land-surfaces in 1–2days, sea-ice and ice-sheets equivalent to those currently provided from ENVISAT MERIS, AATSR and Système Probatoire d'Observation de la Terre (SPOT) Vegetation.
The Sentinel-3 mission addresses these requirements by implementing and operating:•A dual frequency, Synthetic Aperture Radar Altimeter (SRAL) instrument supported by a dual frequency passive microwave radiometer (MWR) for wet-tropospheric correction, a Precise Orbit Determination package including a GPS receiver, a DORIS instrument and a laser retro-reflector.•A highly sensitive Ocean and Land Colour Imager (OLCI) delivering multi-channel wide-swath optical measurements for ocean and land surfaces.•A dual-view Sea and Land Surface Temperature Radiometer (SLSTR) delivering accurate surface ocean, land, and ice temperature.•A collaborative ground segment providing management of the mission, management, development, production and access to core data products in an operational near real time delivery context.
The mission foresees a series of satellites, each having 7-year lifetime, over a 20-year period starting with the launch of Sentinel-3A in late 2013 and of Sentinel-3B in late 2014. During full operations two identical satellites will be maintained in the same orbit with a phase delay of 180°.
This paper provides an overview of the GMES Sentinel-3 mission including the mission background and user requirements, a technical description of the space segment, a brief overview of the ground segment concept, and a summary description of Sentinel-3 data products and their anticipated performance.
► A new satellite mission called Sentinel-3 dedicated to oceanography is described. ► A technical overview of the Sentinel-3 instrument payload is presented. ► A summary of the Sentinel-3 ground segment and operations concept is presented. ► A summary of products derived from Sentinel-3 payload instruments is presented.
INTRODUCTIONThe relative contributions of central versus peripheral factors to the force loss induced by acute continuous and intermittent plantarflexor stretches were studied.
METHODSEighteen ...healthy young men with no apparent tissue stiffness limitations randomly performed 1) one 5-min stretch (continuous stretch CS), 2) five 1-min stretches (intermittent stretch IS), and 3) a control condition, on three separate days. The stretches were constant-torque ankle stretches performed on an isokinetic dynamometer. Gastrocnemius medialis oxygenation status was quantified during stretch using near-infrared spectroscopy. Measures of isometric plantarflexor peak torque (Tpeak), voluntary activation (%VA; interpolated twitch technique), EMG amplitude normalized by Mmax (EMG:M), V-wave amplitude, and excitation–contraction (E–C) coupling efficiency (torque ratio between 20- and 80-Hz tetanic stimulations 20:80) were taken before, immediately, and 15 and 30 min after each condition.
RESULTSIS caused substantial cyclic variations in tissue oxygenation, but CS resulted in a greater decrease in oxyhemoglobin concentration. Voluntary Tpeak decreased more after IS (−23.8%) than CS (−14.3%) and remained significantly depressed until 30 min after IS only (−5.6%). EMG:M (−27.7%) and %VA (−15.9%) were reduced only after IS. After CS and IS, the magnitude of decrease in Tpeak was correlated with decreases in EMG:M (r = 0.81 and 0.89, respectively), %VA (r = 0.78 and 0.93), and V-wave (r = 0.51, only after IS). Tetanic torque values (20 and 80 Hz) were decreased after IS (−13.1% and −6.4%, respectively) and CS (−10.9% and −6.7%, respectively), but 20:80 was not different from the control group.
CONCLUSIONThese results suggest that IS reduced Tpeak more than CS, and these reductions were strongly associated with a depression in central drive.
ICRS are polymethylmethacrylate (PMMA) implants developed to be inserted in the corneal stroma aiming to remodel the ectatic corneal curvature. In 2000, ICRS have been introduced for the implantation ...in KC treatment. Since then, several authors have demonstrated the efficacy of this surgical procedure for improving the refractive and topographic results of KC patients. Moreover, the method has been extended to a larger spectrum of corneal ectasia, such as pellucid marginal degeneration (PMD) and iatrogenic ectasia after laser in situ keratomileusis (LASIK). Our aim was to evaluate the functional results, i.e. how uncorrected and corrected distance visual acuity can be improved by implantation of ICRS. Progression of ectasia seems to be retarded. However, consistent follow‐up visits at close intervals are necessary to identify complications at an early stage. The complications after ICRS implantation are rare due to strict patient selection and modern surgical techniques.
Mycotic keratitis – Experience in Europe Daas, Loay; Hamon, C. Sourlis L.; Seitz, B.
Acta ophthalmologica (Oxford, England),
December 2022, 2022-12-00, 20221201, Letnik:
100, Številka:
S275
Journal Article
Recenzirano
Mycotic keratitis is a rare but severe ophthalmological illness, which has to be taken very seriously with a potentially sight‐threatening outcome. Over the last two decades, an increase of cases ...with mycotic keratitis has been noticed, which has possibly caused an increased use of soft contact lenses. Therapy is often lengthy and difficult. In a lot of cases, surgical therapy, i.e. corneal transplantation is indicated. For this reason, it is essential to discuss during the clarification process the necessity of a keratoplasty during the course of treatment. In this talk, we would like to give an overview on the typical clinical signs, symptoms, diagnostics and therapy options as well as confocal microscopy for diagnosis of mycotic keratitis.
The purpose of the present study was to examine the possible inhibitory effect of passive plantar flexor muscle stretching on the motoneuron facilitatory system. Achilles tendon vibration (70 Hz) and ...triceps surae electrical stimulation (20 Hz) were imposed simultaneously in 11 subjects to elicit contraction through reflexive pathways in two experiments. In experiment 1, a vibration-stimulation protocol was implemented with the ankle joint plantar flexed (+10°), neutral (0°), and dorsiflexed (-10°). In experiment 2, the vibration-stimulation protocol was performed twice before (control), then immediately, 5, 10, and 15 min after a 5-min intermittent muscle stretch protocol. Plantar flexor torque and medial and lateral gastrocnemius and soleus (EMGSol) EMG amplitudes measured during and after (i.e., self-sustained motor unit firing) the vibration protocol were used as an indicator of this facilitatory pathway. In experiment 1, vibration torque, self-sustained torque and EMGSol were higher with the ankle at -10° compared with 0° and +10°, suggesting that this method is valid to assess motoneuronal facilitation. In experiment 2, torque during vibration was reduced by ∼ 60% immediately after stretch and remained depressed by ∼ 35% at 5 min after stretch (P < 0.05). Self-sustained torque was also reduced by ∼ 65% immediately after stretch (P < 0.05) but recovered by 5 min. Similarly, medial gastrocnemius EMG during vibration was reduced by ∼ 40% immediately after stretch (P < 0.05), and EMGSol during the self-sustained torque period was reduced by 44% immediately after stretch (P < 0.05). In conclusion, passive stretch negatively affected the motoneuronal amplification for at least 5 min, suggesting that motoneuron disfacilitation is a possible mechanism influencing the stretch-induced torque loss.
Objective: To determine the point prevalence of painful musculoskeletal (MSK) conditions in obese subjects before and after weight loss following bariatric surgery. Design: Longitudinal, ...interventional, unblended. Subjects: Forty-eight obese subjects (47 women, one man, mean age 44+/-9 years; mean body mass index (BMI) 51+/-8 kg/m2) recruited from an academic medical center bariatric surgery program. Measurements: Comorbid medical conditions; MSK findings; BMI; Western Ontario McMaster Osteoarthritis Index (WOMAC) for pain, stiffness and function; and SF-36 for quality of life. Methods: Consecutive subjects were recruited from the University Hospitals of Cleveland Bariatric Surgery Program. Musculoskeletal signs and symptoms and non-MSK comorbid conditions were documented at baseline and at follow-up. Subjects completed the SF-36 and the WOMAC questionnaires. Analyses were carried out for each MSK site, fibromyalgia syndrome (FMS) and for the cumulative effect on the spine, upper and lower extremities. The impact of change in comorbid medical conditions, BMI, physical and mental health domains of the SF-36 on the WOMAC pain subscale score was evaluated. SF-36 outcomes were compared to normal published controls. Results: Forty-eight subjects were available for baseline and a follow-up assessment 6-12 months after gastric bypass surgery. They lost an average of 41+/-15 kg and the mean BMI decreased from 51+/-8 to 36+/-7 kg/m2. Baseline comorbid medical conditions were present in 96% before surgery and 23% after weight loss. There was an increased prevalence of painful MSK conditions at baseline compared to general population frequencies. Musculoskeletal complaints had been present in 100% of obese subjects before, and 23% after weight loss. The greatest improvements occurred in the cervical and lumbar spine, the foot and in FMS (decreased by 90, 83, 83 and 92%, respectively). Seventy-nine percent had upper extremity MSK conditions before and 40% after weight loss. Before surgery, 100% had lower extremity MSK conditions and only 37% did after weight loss. The WOMAC subscale and composite scores all improved significantly, as did the SF-36. Change in BMI was the main factor impacting the WOMAC pain score. Conclusion: There was a higher frequency of multiple MSK complaints, including non-weight-bearing sites compared to historical controls, before surgery, which decreased significantly at most sites following weight loss and physical activity. These benefits may improve further, as weight loss may continue for up to 24 months. The benefits seen with weight loss indicate that prevention and treatment of obesity can improve MSK health and function.
The OLYMPUS Collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, R_{2γ}, a direct measure of the contribution of hard two-photon ...exchange to the elastic cross section. In the OLYMPUS measurement, 2.01 GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillators detected elastically scattered leptons in coincidence with recoiling protons over a scattering angle range of ≈20° to 80°. The relative luminosity between the two beam species was monitored using tracking telescopes of interleaved gas electron multiplier and multiwire proportional chamber detectors at 12°, as well as symmetric Møller or Bhabha calorimeters at 1.29°. A total integrated luminosity of 4.5 fb^{-1} was collected. In the extraction of R_{2γ}, radiative effects were taken into account using a Monte Carlo generator to simulate the convolutions of internal bremsstrahlung with experiment-specific conditions such as detector acceptance and reconstruction efficiency. The resulting values of R_{2γ}, presented here for a wide range of virtual photon polarization 0.456<ε<0.978, are smaller than some hadronic two-photon exchange calculations predict, but are in reasonable agreement with a subtracted dispersion model and a phenomenological fit to the form factor data.
Purpose
We examined the effect of muscle stretching on the ability to produce rapid torque and the mechanisms underpinning the changes.
Methods
Eighteen men performed three conditions: (1) continuous ...stretch (1 set of 5 min), (2) intermittent stretch (5 sets of 1 min with 15-s inter-stretch interval), and (3) control. Isometric plantar flexor rate of torque development was measured during explosive maximal voluntary contractions (MVC) in the intervals 0–100 ms (RTD
V100
) and 0–200 ms (RTD
V200
), and in electrically evoked 0.5-s tetanic contractions (20 Hz, 20 Hz preceded by a doublet and 80 Hz). The rate of EMG rise, electromechanical delay during MVC (EMD
V
) and during a single twitch contraction (EMD
twitch
) were assessed.
Results
RTD
V200
was decreased (
P
< 0.05) immediately after continuous (− 15%) and intermittent stretch (− 30%) with no differences between protocols. The rate of torque development during tetanic stimulations was reduced (
P
< 0.05) immediately after continuous (− 8%) and intermittent stretch (− 10%), when averaged across stimulation frequencies. Lateral gastrocnemius rate of EMG rise was reduced after intermittent stretch (− 27%), and changes in triceps surae rate of EMG rise were correlated with changes in RTD
V200
after both continuous (
r
= 0.64) and intermittent stretch (
r
= 0.65). EMD
V
increased immediately (31%) and 15 min (17%) after intermittent stretch and was correlated with changes in RTD
V200
(
r
= − 0.56). EMD
twitch
increased immediately after continuous (4%), and immediately (5.4%), 15 min (6.3%), and 30 min after (6.4%) intermittent stretch (
P
< 0.05).
Conclusions
Reductions in the rate of torque development immediately after stretching were associated with both neural and mechanical mechanisms.
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