The influence of the meandering Guiana Current on surface conditions near Barbados - temporal variations of Trichodesmium (Cyanophyta) and other plankton

The temporal fluctuations of the surface layer Trichodesmium (Cyanophyta) populations off Barbados which occur at roughly three-month intervals are shown to be accompanied by in-phase fluctuations of both the numbers and species composition of other phytoplankton and surface dwelling zooplankton...

The influence of the meandering Guiana Current and Amazon River discharge on surface salinity near Barbados

The seasonal surface salinity regime near Barbados, West Indies is explained in terms of the oceanography of the area. Because of its position relative to the complex and meandering Guiana Current along the northeast coast of South America, the island of Barbados receives mixtures of two fundamentally different surface water types...

Phytoplankton Chlorophyll Distribution in the Eastern Canadian Arctic

The distribution of phytoplankton chlorophyll concentration in Jones Sound, Lancaster Sound, and Eastern Baffin Bay was studied during the period 16-27 August 1979, using continuous ship-based horizontal and vertical profiling and continuous aerial water colour measurements. These data are discussed in relation to physical data collected from the ship, and to infrared temperature measurements made from the aircraft and the TIROS series satellites. While the satellite and airborne remote sensing techniques are capable only of viewing the near-surface layer, they provided a much more detailed and synoptic coverage of this large area than was possible using a vessel alone. Together the three types of data provide a reasonably detailed picture of phytoplankton distribution which compares well with other physical oceanographic data. On average the chlorophyll standing crop was moderate (69 mg/sq m in the top 35 m, n=24) and comparable to that reported for other open-water arctic regions, but the phytoplankton were not evenly distributed vertically or geographically. In Jones Sound and Lancaster Sound where local ice melt reduced the surface water density, strong subsurface chlorophyll maxima (up to 18 mg/cu m in a 1 m thick layer) were observed in association with the pycnoline. At the mouths of these sounds and along the eastern coast of Devon, Bylot, and Baffin islands the phytoplankton distribution was more vertically homogeneous and closely linked to the physical structure of the Baffin Current. Highest pigment concentrations were associated with eddies or meanders in the current. It is possible that these localized pigment concentrations are one manifestation of "biological hotspots" which help feed the large populations of marine birds and mammals of the eastern Arctic.Key words: phytoplankton, chlorophyll, distribution, eastern Canadian Arctic, remote sensingMots clés: phytoplancton, chlorophylle, distribution, l'est de l'Arctique canadien, télédétectio

Comparative assessment of the comfort of two soft contact lenses

Background: Perception of lens comfort is a critical factor and predictor of whether or not an individual will be able to successfully achieve refractive correction with contact lenses. Recent advances in lens materials raise the question of which materials are the best to prescribe. It is important to have some basis on which to compare the various materials in regards to comfort in addition to standard lab bench tests such as Dk and hydration percentage. Methods: The purpose of this study was to compare Brand A, a silicone hydrogel lens, with Brand B, a conventional hydrogel lens, in regards to wearer comfort. Twenty-nine subjects were randomly assigned to wear either Brand A or Brand B for four weeks and then the other brand for four weeks. Twenty-six subjects successfully completed the study. Subjects returned for follow-up visits at two and four week intervals after the initial fitting of each brand. Comfort was rated by acquiring subjective reports regarding comfortable wearing time and by marking an analogue comfort scale. Subjects also kept a home journal for recording comfort levels. Results: Statistical analysis showed virtually no difference in the subjects\u27 responses between the left and right eyes. As such only the data for the right eye was fully analyzed. The order in which the lenses were assigned was determined to not have a significant effect in the results; consequently, data was analyzed by brand without concern for an order effect. A slight decrease in comfort was noted for both brands from the two week reporting time to the 4 week reporting time. Conclusion: The data showed no significant difference between the brands in either subject comfort response or subjective hours of comfortable wear. It can be inferred that both Brand A and Brand B performed equally well in the perceived wearer comfort. This suggests that current silicone hydrogel lenses are as effective at maintaining sufficient lens hydration as conventional hydrogel lenses thereby providing an equally effective level of comfort longevity

The effects of monovision on distance stereopsis and driving performance

The effects of monovision on stereopsis and driving performance were evaluated on thirty-eight subjects (ages 22 to 55 years). Monovision performance was compared to the performance with distance contact lenses. Each subject had good ocular health, no apparent strabismus, and less than 1.00D of uncorrected astigmatism. Visual acuity and stereo acuity at 6m and 40cm, acuity suppression at 6m, and driving performance were measured for each condition. The results of the study indicated that mono vision reduced several aspects of visual performance. A significant difference (t=11.82, p=0.0001, df-=35) was present for distance visual acuity between the eye corrected for near compared to the eye corrected for distance. Near stereo acuity (t=3.16, p=0.0033, df=34) and distance stereo acuity (t=7.43, p=0.0001, df=20) were both significantly decreased with the monovision modality. The monovision lens showed a significant increase (t=-3.42, p=0.0016, df=35) in the amount of driving error. The statistical results were skewed because only those subject that were affected the least by monovision were analyzed. The subjects whose grossest level of stereo acuity and acuity suppression fell outside the measurable limits of the BVAT were excluded from the statistical analysis

Representation of sharp rifts and faults mechanics in modeling ice shelf flow dynamics: Application to Brunt/Stancomb-Wills Ice Shelf, Antarctica

Ice shelves play a major role in buttressing ice sheet flow into the ocean, hence the importance of accurate numerical modeling of their stress regime. Commonly used ice flow models assume a continuous medium and are therefore complicated by the presence of rupture features (crevasses, rifts, and faults) that significantly affect the overall flow patterns. Here we apply contact mechanics and penalty methods to develop a new ice shelf flow model that captures the impact of rifts and faults on the rheology and stress distribution of ice shelves. The model achieves a best fit solution to satellite observations of ice shelf velocities to infer the following: (1) a spatial distribution of contact and friction points along detected faults and rifts, (2) a more realistic spatial pattern of ice shelf rheology, and (3) a better representation of the stress balance in the immediate vicinity of faults and rifts. Thus, applying the model to the Brunt/Stancomb-Wills Ice Shelf, Antarctica, we quantify the state of friction inside faults and the opening rates of rifts and obtain an ice shelf rheology that remains relatively constant everywhere else on the ice shelf. We further demonstrate that better stress representation has widespread application in examining aspects affecting ice shelf structure and dynamics including the extent of ice mélange in rifts and the change in fracture configurations. All are major applications for better insight into the important question of ice shelf stability

The effectiveness of surgical correction of uterine prolapse: cervical amputation with uterosacral ligament plication (modified Manchester) versus vaginal hysterectomy with high uterosacral ligament plication

Item does not contain fulltextINTRODUCTION AND HYPOTHESIS: The objective of this study is to evaluate cervical amputation with uterosacral ligament plication (modified Manchester) and compare it to vaginal hysterectomy with high uterosacral ligament plication procedure with special regard to the middle compartment. METHODS: Consecutive women with pelvic organ prolapse who underwent either vaginal hysterectomy or a modified Manchester procedure were included. Assessments were made preoperatively and at 1-year follow-up, including physical examination with pelvic organ prolapse quantification standardised questionnaires (incontinence impact questionnaire, urogenital distress inventory, and defaecatory distress inventory). RESULTS: Between 2002 and 2007, 156 patients were included. Ninety-eight patients returned for a 1-year follow-up. In the modified Manchester group, we found no middle compartment recurrence versus two (4%) in the vaginal hysterectomy group. Anterior and posterior compartment prolapse recurrences (stage >or=2) were similar (approximately 50%). Considering operating time and blood loss, modified Manchester was more favourable. There was no difference in the pre- and postoperative subjective scores. The overall functional outcome was acceptable. CONCLUSIONS: We found an excellent performance of both procedures regarding middle compartment recurrences

Posterior shoulder tightness; an intersession reliability study of 3 clinical tests.

Background Although posterior shoulder tightness (PST) has been associated with shoulder pathology and altered glenohumeral joint kinematics, uncertainty remains regarding its cause and definition. To understand the efficacy of treatments for PST, it must be possible to identify people with PST for the purposes of research and clinical decision-making. Clinical tests for PST must demonstrate acceptable levels of measurement reliability in order to identify the condition and to evaluate the response to intervention. There is currently a lack of research describing intersession reliability for measures of PST. The aim of this study was to quantify the inter-session reliability for three clinical tests used to identify PST over a 6–10 week interval. Methods A convenience sample of 26 asymptomatic adult participants (52 shoulders) were recruited from a university setting over a five-month duration. Participants attended the human movement laboratory for measurement of glenohumeral joint internal rotation, horizontal adduction and low flexion on two occasions separated by an interval of 6–10 weeks. Intra-class correlation coefficients were calculated from the mean square values derived from the within-subject, single factor (repeated measures) ANOVA. Test-retest measurement stability was evaluated by calculating the standard error of measurement and the minimum detectable change for each measurement. Results All 3 tests demonstrated good intersession intra-rater reliability (0.86–0.88), and the standard error of measurement (95%) were 7.3° for glenohumeral horizontal adduction, 9.4° for internal rotation, and 6.9° for low flexion. The minimum detectable change for glenohumeral horizontal adduction was 10.2°, internal rotation was 13.3°, and low flexion was 9.7°. Conclusion In this population of people without symptoms, the 3 measures of PST all demonstrated acceptable inter-session reliability. The standard error of measurement and minimum detectable change results can be used to determine if a change in measures of PST are due to measurement error or an actual change over time.Peer reviewe

Protocol for the CUPIDO trials; multicenter randomized controlled trials to assess the value of combining prolapse surgery and incontinence surgery in patients with genital prolapse and evident stress incontinence (CUPIDO I) and in patients with genital prolapse and occult stress incontinence (CUPIDO II)

Background: About 40% of all patients with genital prolapse report stress-incontinence. In about half of the 60% patients that do not report stress-incontinence, occult urinary stress-incontinence can be detected. In these patients stress-incontinence is masked due to kinking or compression of the urethra by the prolapse. In case surgical correction is indicated there are two strategies to manage patients with combined prolapse and (occult) stress incontinence. This strategy is either (i) a combination of prolapse surgery and stress-incontinence surgery or (ii) to correct the prolapse first and evaluate afterwards whether additional stress-incontinence surgery is indicated. The advantage of combining prolapse and stress-incontinence surgery is that only few patients report stress-incontinence following such combination. However, this combination has been associated with an increased risk on complications, of which the development of obstructive micturition symptoms, overactive bladder symptoms and bladder retention are the most important ones. Furthermore, combining two procedures may be unnecessary as performing only prolapse surgery may cure stress-incontinence In the randomized CUPIDO trials both strategies are compared in patients with prolapse and evident stress incontinence (CUPIDO I trial) and in patients with prolapse and occult stress incontinence (CUPIDO II trial). Methods/Design: The CUPIDO trials are two multicenter randomized controlled trials in which women with stress urinary incontinence (SUI) or occult stress urinary incontinence (OSUI) are randomized to prolapse surgery combined with anti incontinence surgery (concomitant surgery) or to prolapse surgery only. Patients with at least stage 2 POP are eligible, women with evident SUI are randomized in CUPIDO I. Patients without SUI are eligible for CUPIDO II and will have urodynamic evaluation or a standardized redression test. Women with OSUI are randomized, women without OSUI are followed up but not randomized. The primary outcome measure is absence of SUI twelve months after surgery. Furthermore, economic evaluations are conducted, and the effectiveness of urodynamic investigation is evaluated against a non-invasive way to determine SUI in women with POP. A total of 450 women will be included in the study