1,708 research outputs found

    Giantism in Oligocene planktonic foraminifera Paragloborotalia opima: Morphometric constraints from the equatorial Pacific Ocean

    Get PDF
    The extinction of Oligocene planktonic foraminifera Paragloborotalia opima is an important biostratigraphic marker for the upper Oligocene (base Zone O6 [P22]), however the taxonomy of the morphospecies is unclear and therefore its biostratigraphic use is compromised. We conducted morphometric and scanning electron microscope analyses on the Paragloborotalia opima-nana plexus and investigated whether the two morphospecies P. opima (Bolli) and P. nana (Bolli) could be quantitatively separated or formed a continuous morphocline. These two morphospecies have previously been classified by their diameter, with P. opima defined as the larger morphospecies (0.39–0.55 mm) and P. nana confined to 0.32 mm. The problem with this classification is that many specimens fall between 0.32 and 0.39 mm. We measured the maximum size of 1215 specimens of Paragloborotalia from equatorial Pacific Ocean Integrated Ocean Drilling Program Site U1334, corresponding to planktonic foraminiferal Biozones O6–O2 and Chrons C8r to C11r (26.3 to 30.8 Ma). We found that the number of chambers and shape outline could not be used to determine these two morphotypes of Paragloborotalia, but size is a suitable delimiting character. We therefore reassess the taxonomy of the opima-nana plexus. Our data confirm that the 'transition' forms are consistent with P. opima and that the 0.32 mm criterion is valid for the identification of P. nana. Through the studied interval the maximum size of P. opima increases from 0.44 mm to 0.68 mm, with the largest specimens in the upper Oligocene in the lower part of Chron C9n. We propose that the progressive giantism of P. opima through the mid-late Oligocene in the equatorial Pacific Ocean is in response to high productivity

    Investigating the Correlation Between LPR & Obesity

    Get PDF
    Objectives: To determine whether Drug-Induced Sleep Endoscopy (DISE) findings of Laryngopharyngeal Reflux (LPR) correlate with obesity, gender, Epworth Sleepiness scale, and OSA severity. Study design: Single center retrospective cohort study. Methods: Patients greater than 18 years of age who underwent DISE by one surgeon at a tertiary care center from July 2016 to July 2022 were included. DISE findings, patient characteristics, demographics, polysomnogram(s), and Epworth Sleepiness Scale(s) were extracted. Fisher’s exact test was used to compare categorical variables, and independent sample t-test was used to compare continuous variables. All statistical analyses were performed using IBM SPSS Statistics 28. Results: The study included 178 patients (60.87 years ± 11.54; 31.24 BMI ± 6.21). 38 patients had LPR, and 103 patients had a BMI\u3e30. LPR+ patients BMI was 33.11 ± 5.60, and LPR- patients BMI was 30.74 ± 6.28. There was a statistically significant relationship between obesity and LPR (p = 0.005). Additionally, obesity mild-moderately affected patients having LPR (d = .404). There was no statistically significant difference between LPR+ patients and ESS, AHI, and gender (p = .395, .174, & .302 respectively). Conclusion: DISE aids in the diagnosis and evaluation of Obstructive Sleep Apnea (OSA) by simulating natural sleep. Using this highly precise diagnostic procedure, our study shows a relationship between findings of LPR in obese patients with obesity playing a small-medium role. There was no difference between LPR and ESS, AHI, and gender

    Biotic and abiotic retention, recycling and remineralization of metals in the ocean

    Get PDF
    Trace metals shape both the biogeochemical functioning and biological structure of oceanic provinces. Trace metal biogeochemistry has primarily focused on modes of external supply of metals from aeolian, hydrothermal, sedimentary and other sources. However, metals also undergo internal transformations such as abiotic and biotic retention, recycling and remineralization. The role of these internal transformations in metal biogeochemical cycling is now coming into focus. First, the retention of metals by biota in the surface ocean for days, weeks or months depends on taxon-specific metal requirements of phytoplankton, and on their ultimate fate: that is, viral lysis, senescence, grazing and/or export to depth. Rapid recycling of metals in the surface ocean can extend seasonal productivity by maintaining higher levels of metal bioavailability compared to the influence of external metal input alone. As metal-containing organic particles are exported from the surface ocean, different metals exhibit distinct patterns of remineralization with depth. These patterns are mediated by a wide range of physicochemical and microbial processes such as the ability of particles to sorb metals, and are influenced by the mineral and organic characteristics of sinking particles. We conclude that internal metal transformations play an essential role in controlling metal bioavailability, phytoplankton distributions and the subsurface resupply of metals

    Mechanosensitivity during lower extremity neurodynamic testing is diminished in individuals with Type 2 Diabetes Mellitus and peripheral neuropathy: a cross sectional study

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Type 2 Diabetes Mellitus (T2DM) and diabetic symmetrical polyneuropathy (DSP) impact multiple modalities of sensation including light touch, temperature, position sense and vibration perception. No study to date has examined the mechanosensitivity of peripheral nerves during limb movement in this population. The objective was to determine the unique effects T2DM and DSP have on nerve mechanosensitivity in the lower extremity.</p> <p>Methods</p> <p>This cross-sectional study included 43 people with T2DM. Straight leg raise neurodynamic tests were performed with ankle plantar flexion (PF/SLR) and dorsiflexion (DF/SLR). Hip flexion range of motion (ROM), lower extremity muscle activity and symptom profile, intensity and location were measured at rest, first onset of symptoms (P1) and maximally tolerated symptoms (P2).</p> <p>Results</p> <p>The addition of ankle dorsiflexion during SLR testing reduced the hip flexion ROM by 4.3° ± 6.5° at P1 and by 5.4° ± 4.9° at P2. Individuals in the T2DM group with signs of severe DSP (n = 9) had no difference in hip flexion ROM between PF/SLR and DF/SLR at P1 (1.4° ± 4.2°; paired t-test p = 0.34) or P2 (0.9° ± 2.5°; paired t-test p = 0.31). Movement induced muscle activity was absent during SLR with the exception of the tibialis anterior during DF/SLR testing. Increases in symptom intensity during SLR testing were similar for both PF/SLR and DF/SLR. The addition of ankle dorsiflexion induced more frequent posterior leg symptoms when taken to P2.</p> <p>Conclusions</p> <p>Consistent with previous recommendations in the literature, P1 is an appropriate test end point for SLR neurodynamic testing in people with T2DM. However, our findings suggest that people with T2DM and severe DSP have limited responses to SLR neurodynamic testing, and thus may be at risk for harm from nerve overstretch and the information gathered will be of limited clinical value.</p

    The interplay between regeneration and scavenging fluxes drives ocean iron cycling

    Get PDF
    Despite recent advances in observational data coverage, quantitative constraints on how different physical and biogeochemical processes shape dissolved iron distributions remain elusive, lowering confidence in future projections for iron-limited regions. Here we show that dissolved iron is cycled rapidly in Pacific mode and intermediate water and accumulates at a rate controlled by the strongly opposing fluxes of regeneration and scavenging. Combining new data sets within a watermass framework shows that the multidecadal dissolved iron accumulation is much lower than expected from a meta-analysis of iron regeneration fluxes. This mismatch can only be reconciled by invoking significant rates of iron removal to balance iron regeneration, which imply generation of authigenic particulate iron pools. Consequently, rapid internal cycling of iron, rather than its physical transport, is the main control on observed iron stocks within intermediate waters globally and upper ocean iron limitation will be strongly sensitive to subtle changes to the internal cycling balance

    Contact lens rehabilitation following repaired corneal perforations

    Get PDF
    BACKGROUND: Visual outcome following repair of post-traumatic corneal perforation may not be optimal due to presence of irregular keratometric astigmatism. We performed a study to evaluate and compare rigid gas permeable contact lens and spectacles in visual rehabilitation following perforating corneal injuries. METHOD: Eyes that had undergone repair for corneal perforating injuries with or without lens aspiration were fitted rigid gas permeable contact lenses. The fitting pattern and the improvement in visual acuity by contact lens over spectacle correction were noted. RESULTS: Forty eyes of 40 patients that had undergone surgical repair of posttraumatic corneal perforations were fitted rigid gas permeable contact lenses for visual rehabilitation. Twenty-four eyes (60%) required aphakic contact lenses. The best corrected visual acuity (BCVA) of ≥ 6/18 in the snellen's acuity chart was seen in 10 (25%) eyes with spectacle correction and 37 (92.5%) eyes with the use of contact lens (p < 0.001). The best-corrected visual acuity with spectacles was 0.20 ± 0.13 while the same with contact lens was 0.58 ± 0.26. All the patients showed an improvement of ≥ 2 lines over spectacles in the snellen's acuity chart with contact lens. CONCLUSION: Rigid gas permeable contact lenses are better means of rehabilitation in eyes that have an irregular cornea due to scars caused by perforating corneal injuries
    corecore