An Analysis of the Long-Term Salinity Patterns in the Louisiana Coastal Zone

Saltwater intrusion is believed to be one of the greatest threats to Louisiana\u27s fishery and wildlife resources. The Louisiana Department of Wildlife and Fisheries has maintained salinity recording stations throughout the state\u27s coastal marshes since the 1960\u27s. We applied several different analytical approaches to the salinity data from 17 stations to determine whether this data base could be used to detect and quantity long-term salinity trends in coastal Louisiana. We did not detect a large-scale, consistent trend over time in coastal salinities across the state. Problems that hindered the detection of long-term trends included short periods of record and the placement of the recording stations in salt and brackish marsh areas, where we would not expect to find great changes in salinity. For the data to be useful in monitoring salinity trends in coastal marshes, especially with respect to saltwater intrusion, stations should be added in fresh and intermediate marshes. In addition, the relationships our study revealed between short- and long-term data indicate that records covering less than a decade are insufficient to denote long-term salinity changes, barring some major modification of the hydrologic regime

Emerging wetlands from river diversions can sustain high denitrification rates in a Coastal Delta

Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Biogeosciences 126(5), (2021): e2020JG006217, https://doi.org/10.1029/2020JG006217.It is assumed that to treat excess NO3− high soil organic matter content (%OM) is required to maintain high denitrification rates in natural or restored wetlands. However, this excess also represents a risk by increasing soil decomposition rates triggering peat collapse and wetland fragmentation. Here, we evaluated the role of %OM and temperature interactions controlling denitrification rates in eroding (Barataria Bay-BLC) and emerging (Wax Lake Delta-WLD) deltaic regions in coastal Louisiana using the isotope pairing (IPT) and N2:Ar techniques. We also assessed differences between total (direct denitrification + coupled nitrification-denitrification) and net (total denitrification minus nitrogen fixation) denitrification rates in benthic and wetland habitats with contrasting %OM and bulk density (BD). Sediment (benthic) and soil (wetland) cores were collected during summer, spring, and winter (2015–2016) and incubated at close to in-situ temperatures (30°C, 20°C, and 10°C, respectively). Denitrification rates were linearly correlated with temperature; maximum mean rates ranged from 40.1–124.1 μmol m−2 h−1 in the summer with lower rates (30 μM) and water temperature is >10°C. In coastal Louisiana, substrates under these regimes are represented by emergent supra-tidal flats or land created by sediment diversions under oligohaline conditions (<1 ppt).This study was supported by the NOAA-Sea Grant Program-Louisiana (Grant 2013R/E-24) to Victor H. Rivera-Monroy and Kanchan Maiti. Victor H. Rivera-Monroy was also supported by the Department of the Interior South-Central Climate Adaptation Science Center (Cooperative Agreement #G12AC00002)

Observation on the ultrastructure morphology of HeLa cells treated with ethanol: Statistical analysis.

It is estimated that 5.9% of all human deaths are attributable to alcohol consumption and that the harmful use of ethanol ranks among the top five risk factors for causing disease, disability, and death worldwide. Ethanol is known to disrupt phospholipid packing and promote membrane hemifusion at lipid bilayers. With the exception of mitochondria involved in hormone synthesis, the sterol content of mitochondrial membranes is low. As membranes that are low in cholesterol have increased membrane fluidity and are the most easily disordered by ethanol, we hypothesize that mitochondria are sensitive targets for ethanol damage. HeLa cells were exposed to 50 mM ethanol and the direct effects of ethanol on cellular ultrastructure were examined utilizing transmission electron microscopy. Our ultramicroscopic analysis revealed that cells exposed to ethanol harbor fewer incidence of apoptotic morphology; however, significant alterations to mitochondria and to nuclei occurred. We observed statistical increases in the amount of irregular cells and cells with multiple nuclei, nuclei harboring indentations, and nuclei with multiple nucleolus-like bodies. Indeed, our analysis revealed that mitochondrial damage is the most extensive type of cellular damage. Rupturing of cristae was the most prominent damage followed by mitochondrial swelling. Ethanol exposure also resulted in increased amounts of mitochondrial rupturing, organelles with linked membranes, and mitochondria localizing to indentations of nuclear membranes. We theorize that these alterations could contribute to cellular defects in oxidative phosphorylation and, by extension, the inability to generate regular levels of cellular adenosine triphosphate

Stability and reproducibility of brachial artery flow-mediated dilation

Purpose: Brachial artery flow-mediated dilation (BAFMD) is a noninvasive technique, which has been suggested as a potential means of identifying patients with early atherosclerosis and therefore has enormous clinical appeal. Despite this, the stability and reproducibility of this technique are not yet clear. Therefore, the purpose of this study was to establish the stability and reproducibility of BAFMD after 5 min of forearm occlusion and to produce power calculations to aid in clinical trial design. Methods: Twenty-six healthy volunteers underwent high-resolution ultrasonographic brachial artery assessments before, during, and after 5 min of forearm occlusion. The study design involved three scans on 2 d, performed by two ultrasonographers and analyzed by two readers. All subjects were tested between 7 and 11 a.m. after refraining from food and exercise. The nondominant arms were scanned, in longitudinal view, approximately 4 cm proximal to the olecranon process, in the anterior/medial plane. Blood draws were performed on each visit. The SAS MIXED restricted maximum likelihood (REML) procedure for an unbalanced design was used to calculate variance components and provide power calculations. Results: Average baseline artery diameter for all studies was 3.48 ± 0.53 mm. This increased to 3.71 ± 0.57 mm (6.58 ± 4.15%) at peak dilation. Intraclass correlation coefficients (ICCC) for days, testers, and readers were 0.92, 0.94, and 0.90, respectively. To detect a difference in vasoreactivity of 60% (two-tailed), e.g., 5% vasodilation versus 8% vasodilation, at 90% power, 23 and 10 subjects would be required for cross-sectional and pre-post designs, respectively. Conclusions: These data indicate adequate stability and reproducibility of the BAFMD technique under controlled conditions. Additionally, BAFMD appears useful to differentiate between groups, although its prognostic value for the examination of individuals is unclear

Radial wood allocation in Schizolobium parahyba

PREMISE OF THE STUDY: Pioneer species of tropical trees allocate wood specific gravity (SG) differently across the radius. Some species exhibit relatively uniform, low SG wood, whereas many others exhibit linear increases in SG across the radius. Here, we measured changes in SG across the radius of Schizolobium parahyba (Fabaceae-Caesalpinioideae), a wide-ranging, neotropical pioneer, used extensively in land reclamation and forest restoration in Brazil. METHODS: Pith-to-bark radial wood cores were extracted with increment borers from 42 trees at five sites, in Central and South America. Cores were cut into 1-cm segments whose specific gravities were determined and analyzed via linear and nonlinear regression. Wood specific gravity, very low initially at 0.15-0.20, doubled or tripled across the tree radius to 0.45-0.65 for large adults. KEY RESULTS: Unlike linear increases in other tropical pioneers, the increases in Schizolobium were nonlinear (convex up). At one site with even-aged trees, the magnitude of the radial increase was similar in all trees, despite a 4-fold difference in diameter among trees, implying that the radial increases in Schizolobium were regulated by tree age, not by tree size. CONCLUSIONS: This unique pattern of development should provide an extended period of growth when SG is low, facilitating hyper-extension of the bole, at some risk of structural failure. Later in growth, the SG rate of increase accelerates, reinforcing what was a precarious bole. Overall, these results suggest a third model for xylem allocation in tropical trees, a model that may be associated with monopodial stem development and limited life span

Time Course of Improved Flow-Mediated Dilation after Short-Term Exercise Training

Purpose: The purpose was to determine the influence of a unilateral localized short-term handgrip training protocol on brachial artery flow-mediated dilation (BAFMD) and to examine the time course of such changes. Methods: Fourteen healthy males (age: 26 ± 5.7 yr) underwent high-resolution ultrasonographic brachial artery assessments before (V1), during (V2–V7), and at the end of 4 wk (V8) of 60% maximal voluntary contraction handgrip training (20 min·d-1, 5 d·wk-1) of the nondominant arm. Results: Before training resting diameters were similar between the trained (nondominant) and untrained (dominant) arms. A 2 (trained and untrained arms) × 2 (V1 and V8) repeated measure ANOVA revealed a significant main (P = 0.02 and P = 0.03) and interaction effect (P = 0.05 and P = 0.01) for the percent and absolute change in BAFMD. BAFMD improved 62% and 70%, respectively from V1 to V8, for the percent and absolute change. Subsequent linear orthogonal polynomial contrasts indicate both the percent and absolute change in BAFMD were statistically different at V2 (end of week 1 and 4 training days) from V1. These unilateral changes were not accompanied by changes in resting artery diameter, hemodynamic measures, hematological markers, and indices of heart rate variability suggesting the change may be locally mediated. Conclusions: This study shows a localized short-term exercise-training program resulted in significant improvements in BAFMD in the trained arm compared with the untrained arm and suggests this occurred after only 4 d of training

Protein Deprivation and Perinatal Weight Changes in Rhesus Monkeys

Forty-six infant rhesus monkeys of both sexes were fed a for­mula containing 3.35%, 6.7%, or 13.4% protein as casein. Their weight gain and food consumption were compared with those of 53 monkeys fed a commercial formula simulating human milk. All groups passed through a three-day weight-loss stage and a transitional stage lasting about one week, after which they entered a rather permanent growth stage. Males ate more than the females did, but only because they weighed more. The lowest- protein diet had no significant deleterious effect on weight gain during the transition phase, and it had no effect on the females’ gain during the growth stage. Males fed the lowest protein diet, in contrast, gained little during the growth stage. The reduction in weight gain seems due to a loss in food efficiency, not to a reduction in consumption