Rings which are Essential over their Centers, II

A ring $R$ with center $C$ is said to be\textit{centrally essential} if the module $R_C$ is an essential extension of the module $C_C$. We describe centrally essential exterior algebras of finitely generated free modules over not necessary commutative rings and study properties of semi-Artinian centrally essential rings. V.T.Markov is supported by the Russian Foundation for Basic Research, project 17-01-00895-A.~ A.A. Tuganbaev is supported by Russian Scientific Foundation, project 16-11-10013

Quantifying subtropical North Pacific gyre mixed layer primary productivity from Seaglider observations of diel oxygen cycles

© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geophysical Research Letters 42 (2015): 4032–4039, doi:10.1002/2015GL063065.Using autonomous underwater gliders, we quantified diurnal periodicity in dissolved oxygen, chlorophyll, and temperature in the subtropical North Pacific near the Hawaii Ocean Time-series (HOT) Station ALOHA during summer 2012. Oxygen optodes provided sufficient stability and precision to quantify diel cycles of average amplitude of 0.6 µmol kg−1. A theoretical diel curve was fit to daily observations to infer an average mixed layer gross primary productivity (GPP) of 1.8 mmol O2 m−3 d−1. Cumulative net community production (NCP) over 110 days was 500 mmol O2 m−2 for the mixed layer, which averaged 57 m in depth. Both GPP and NCP estimates indicated a significant period of below-average productivity at Station ALOHA in 2012, an observation confirmed by 14C productivity incubations and O2/Ar ratios. Given our success in an oligotrophic gyre where biological signals are small, our diel GPP approach holds promise for remote characterization of productivity across the spectrum of marine environments.The authors acknowledge support from the National Science Foundation (NSF) through an NSF Science and Technology Center, the Center for Microbial Oceanography Research and Education (C-MORE; NSF EF-0424599). D.N. also was supported by NSF (OCE-1129644) and an Independent Study Award from the Woods Hole Oceanographic Institution (WHOI). D.M.K. was also supported by the Gordon and Betty Moore Foundation. WHOI Summer Student Fellow Cole Stites-Clayton, Stanford University, contributed to early stages of Seaglider data analysis and was supported by an NSF REU grant to WHOI (OCE-1156952)

Impact of hydration status on electromyography and ratings of perceived exertion during the vertical jump

Copyright (c) the author(s). This is an open access article under CC BY license (https://creativecommons.org/licenses/by/4.0/) Background: The vertical jumping task is commonly used to assess lower-body power output in athletic populations, in addition to being commonly used to during investigations of hydration and anaerobic performance. Changes in neuromuscular function during a hypohydrated state have been proposed as a potential mechanism to decreases in anaerobic performance. Objectives: The primary purpose of this investigation was to examine the impact of hydration state on electromyography during the vertical jumping task. Methods: Twenty recreationally trained males were tested in three hydration conditions (hypohydrated, euhydrated, and control). Testing included maximal voluntary contractions of the vastus lateralis, vastus medialis, semitendinosus and medial gastrocnemius. Participants performed three maximal countermovement and squat jumps respectively for a total of six jumps in each condition. Both mean muscle activity and percentage of maximal voluntary contraction were calculated across the propulsive phase of each jump. Additionally, measures of RPE and the use of a mood rating scale were used as subjective measures. Results: No differences were seen in mean muscle activity and percentage of MVC in either of the jumping conditions (p \u3e 0.05). Significant differences were seen with higher ratings of perceived exertion as well as lower levels of mood ratings after the hypohydrated condition (p = 0.02 and p = 0.048 respectively). Conclusions: Decrements seen in vertical jump performance during a hypohydrated state appear to be caused from changes other than neuromuscular function and muscle activity. Differences in subjective measures may provide insight into changes in motivational levels and potentially impacting performance

Impact of Hydration Status On Electromyography and Ratings of Perceived Exertion During the Vertical Jump

Background: The vertical jumping task is commonly used to assess lower-body power output in athletic populations, in addition to being commonly used to during investigations of hydration and anaerobic performance. Changes in neuromuscular function during a hypohydrated state have been proposed as a potential mechanism to decreases in anaerobic performance. Objectives: The primary purpose of this investigation was to examine the impact of hydration state on electromyography during the vertical jumping task. Methods: Twenty recreationally trained males were tested in three hydration conditions (hypohydrated, euhydrated, and control). Testing included maximal voluntary contractions of the vastus lateralis, vastus medialis, semitendinosus and medial gastrocnemius. Participants performed three maximal countermovement and squat jumps respectively for a total of six jumps in each condition. Both mean muscle activity and percentage of maximal voluntary contraction were calculated across the propulsive phase of each jump. Additionally, measures of RPE and the use of a mood rating scale were used as subjective measures. Results: No differences were seen in mean muscle activity and percentage of MVC in either of the jumping conditions (p \u3e 0.05). Significant differences were seen with higher ratings of perceived exertion as well as lower levels of mood ratings after the hypohydrated condition (p = 0.02 and p = 0.048 respectively). Conclusions: Decrements seen in vertical jump performance during a hypohydrated state appear to be caused from changes other than neuromuscular function and muscle activity. Differences in subjective measures may provide insight into changes in motivational levels and potentially impacting performance

Impact of Hydration Status on Jump Performance in Recreationally Trained Males

International Journal of Exercise Science 13(4): 826-836, 2020. The vertical jump is commonly used as a means of evaluating athlete readiness. Athletes have been shown to arrive to training and competition in a hypohydrated state. Thus, this investigation sought to examine the impact of hydration status on both countermovement (CMJ) and squat jump (SJ) performance. Twenty-five recreationally trained males completed three CMJ and SJ in a euhydrated, hypohydrated and control condition. Conditions were separated by a minimum of 24 hours. Hydration status was assessed using urine specific gravity. Jump performance was evaluated using both kinematic and kinetic data obtained from a force platform. A repeated-measures ANOVA was performed for each variable of interest in both the CMJ and SJ. CMJ peak and mean force values were significantly greater in the euhydrated condition compared to the hypohydrated condition (p \u3c 0.05), with no differences between the control condition and either experimental condition. SJ showed reductions in jump height, peak and mean velocity, peak and mean power and impulse from control and euhydrated conditions (p \u3c 0.05). The findings of this investigation show that when performing jump testing, specifically SJ, that hydration status of the individual may impact commonly used variables to assess the readiness of the individual for a given day

Characterisation of the Temperature-dependent Dark Rate of Hamamatsu R7081-100 10" Photomultiplier Tubes

Dark noise is a dominant background in photomultiplier tubes (PMTs), which are commonly used in liquid-filled particle detectors for single-photon detection to see the results of particle interactions. A major contribution to dark noise is thermionic emission from the photocathode. The dark noise of Hamamatsu R7081-100 PMTs is characterised in a temperature and purity controlled water tank, with the thermionic emission contribution isolated. The results suggest that the intrinsic dark rate of PMTs does not depend on the medium, but does follow Richardson's law of thermionic emission. There are external contributions to the overall observed PMT count rate identified, but the intrinsic PMT dark rate in water matches that measured in air.Comment: 11 pages, 7 figures, 2 tables, prepared for submission to J. Instru

The peripheral blood transcriptome in septic cardiomyopathy: an observational, pilot study.

BACKGROUND:Septic cardiomyopathy (SCM) is common in sepsis and associated with increased morbidity and mortality. Left ventricular global longitudinal strain (LV GLS), measured by speckle tracking echocardiography, allows improved identification of impaired cardiac contractility. The peripheral blood transcriptome may be an important window into SCM pathophysiology. We therefore studied the peripheral blood transcriptome and LV GLS in a prospective cohort of patients with sepsis. RESULTS:In this single-center observational pilot study, we enrolled adult patients (age > 18) with sepsis within 48 h of admission to the ICU. SCM was defined as LV GLS > - 17% based on echocardiograms performed within 72 h of admission. We enrolled 27 patients, 24 of whom had high-quality RNA results; 18 (75%) of 24 had SCM. The group was 50% female and had a median (IQR) age of 59.5 (48.5-67.0) years and admission APACHE II score of 21.0 (16.0-32.3). Forty-six percent had septic shock. After filtering for low-expression and non-coding genes, 15,418 protein coding genes were expressed and 73 had significantly different expression between patients with vs. without SCM. In patients with SCM, 43 genes were upregulated and 30 were downregulated. Pathway analysis identified enrichment in type 1 interferon signaling (adjusted p < 10-5). CONCLUSIONS:In this hypothesis-generating study, SCM was associated with upregulation of genes in the type 1 interferon signaling pathway. Interferons are cytokines that stimulate the innate and adaptive immune response and are implicated in the early proinflammatory and delayed immunosuppression phases of sepsis. While type 1 interferons have not been implicated previously in SCM, interferon therapy (for viral hepatitis and Kaposi sarcoma) has been associated with reversible cardiomyopathy, perhaps suggesting a role for interferon signaling in SCM

Phosphonate cycling supports methane and ethylene supersaturation in the phosphate-depleted western North Atlantic Ocean

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Sosa, O. A., Burrell, T. J., Wilson, S. T., Foreman, R. K., Karl, D. M., & Repeta, D. J. Phosphonate cycling supports methane and ethylene supersaturation in the phosphate-depleted western North Atlantic Ocean. Limnology and Oceanography, (2020), doi:10.1002/lno.11463.In oligotrophic ocean regions, dissolved organic phosphorus (DOP) plays a prominent role as a source of phosphorus (P) to microorganisms. An important bioavailable component of DOP is phosphonates, organophosphorus compounds with a carbon‐phosphorus (C‐P) bond, which are ubiquitous in high molecular weight dissolved organic matter (HMWDOM). In addition to being a source of P, the degradation of phosphonates by the bacterial C‐P lyase enzymatic pathway causes the release of trace hydrocarbon gases relevant to climate and atmospheric chemistry. In this study, we investigated the roles of phosphate and phosphonate cycling in the production of methane (CH4) and ethylene (C2H4) in the western North Atlantic Ocean, a region that features a transition in phosphate concentrations from coastal to open ocean waters. We observed an inverse relationship between phosphate and the saturation state of CH4 and C2H4 in the water column, and between phosphate and the relative abundance of the C‐P lyase marker gene phnJ . In phosphate‐depleted waters, methylphosphonate and 2‐hydroxyethylphosphonate, the C‐P lyase substrates that yield CH4 and C2H4, respectively, were readily degraded in proportions consistent with their abundance and bioavailability in HMWDOM and with the concentrations of CH4 and C2H4 in the water column. We conclude that phosphonate degradation through the C‐P lyase pathway is an important source and a common production pathway of CH4 and C2H4 in the phosphate‐depleted surface waters of the western North Atlantic Ocean and that phosphate concentration can be an important control on the saturation state of these gases in the upper ocean.We thank the captain and crew of the R/V Neil Armstrong and chief scientist Benjamin Van Mooy for supporting and leading research at sea. Chiara Santinelli and Eric Grabowski provided analyses of dissolved organic carbon. This research was funded by NSF Chemical Oceanography award OCE‐1634080 to D.J.R. Additional support was provided by the Gordon and Betty Moore Foundation grant 3794 to D.M.K. and grant 6000 to D.J.R., and the Simons Collaboration on Ocean Processes and Ecology (SCOPE) program grant 329108 to D.M.K., E.F.D., and D.J.R

Light and depth dependency of nitrogen fixation by the non‐photosynthetic, symbiotic cyanobacterium UCYN‐A

The symbiotic cyanobacterium UCYN-A is one of the most globally abundant marine dinitrogen (N2)-fixers, but cultures have not been available and its biology and ecology are poorly understood. We used cultivation-independent approaches to investigate how UCYN-A single-cell N2 fixation rates (NFRs) and nifH gene expression vary as a function of depth and photoperiod. Twelve-hour day/night incubations showed that UCYN-A only fixed N2 during the day. Experiments conducted using in situ arrays showed a light-dependence of NFRs by the UCYN-A symbiosis, with the highest rates in surface waters (5–45 m) and lower rates at depth (≥ 75 m). Analysis of NFRs versus in situ light intensity yielded a light saturation parameter (Ik) for UCYN-A of 44 μmol quanta m−2 s−1. This is low compared with other marine diazotrophs, suggesting an ecological advantage for the UCYN-A symbiosis under low-light conditions. In contrast to cell-specific NFRs, nifH gene-specific expression levels did not vary with depth, indicating that light regulates N2 fixation by UCYN-A through processes other than transcription, likely including host–symbiont interactions. These results offer new insights into the physiology of the UCYN-A symbiosis in the subtropical North Pacific Ocean and provide clues to the environmental drivers of its global distributions.En prens