1,919 research outputs found

    Effects of breaking up prolonged sitting following low and high glycaemic index breakfast consumption on glucose and insulin concentrations

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    Purpose: Breaking up prolonged sitting can attenuate the postprandial rise in glucose and insulin. Whether such effects are dependent of the glycaemic index (GI) of the consumed carbohydrate is unknown. This study examined the acute effects of breaking up prolonged sitting following a low GI and a high GI breakfast on postprandial glucose and insulin concentrations. Procedures: Fourteen adult males aged 22.1 ± 1.2 years completed four, 4 h experimental conditions: high GI breakfast followed by uninterrupted sitting (HGI-SIT), low GI breakfast followed by uninterrupted sitting (LGI-SIT), high GI breakfast followed by 2 min activity breaks every 20 min (HGI-ACT), and low GI breakfast followed by 2 min activity breaks every 20 min (LGI-ACT). Positive incremental area under the curve (iAUC) for glucose and insulin (mean [95% CI]) for each 4h experimental condition was calculated. Statistical analyses were completed using linear mixed models. Results: The sitting × breakfast GI interaction was not significant for glucose positive iAUC (P=0.119). Glucose positive iAUC (mmol/L4 h−1) was significantly lower in the activity breaks conditions than the uninterrupted sitting conditions (2.07 [2.24, 2.89] vs. 2.56 [1.74, 2.40], respectively, P=0.004) and significantly lower in the low GI conditions than the high GI conditions (2.13 [1.80, 2.45] vs. 2.51 [2.18, 2.84], respectively, P=0.022). Insulin concentrations did not differ between conditions (P ≥ 0.203). Conclusions: Breaking up prolonged sitting and lowering breakfast GI independently reduced postprandial glucose responses. This indicates that interrupting prolonged sitting and reducing dietary GI are beneficial approaches for reducing cardiometabolic disease risk

    Seasonal Variability of Saturn's Tropospheric Temperatures, Winds and Para-H2_2 from Cassini Far-IR Spectroscopy

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    Far-IR 16-1000 μ\mum spectra of Saturn's hydrogen-helium continuum measured by Cassini's Composite Infrared Spectrometer (CIRS) are inverted to construct a near-continuous record of upper tropospheric (70-700 mbar) temperatures and para-H2_2 fraction as a function of latitude, pressure and time for a third of a Saturnian year (2004-2014, from northern winter to northern spring). The thermal field reveals evidence of reversing summertime asymmetries superimposed onto the belt/zone structure. The temperature structure that is almost symmetric about the equator by 2014, with seasonal lag times that increase with depth and are qualitatively consistent with radiative climate models. Localised heating of the tropospheric hazes (100-250 mbar) create a distinct perturbation to the temperature profile that shifts in magnitude and location, declining in the autumn hemisphere and growing in the spring. Changes in the para-H2_2 (fpf_p) distribution are subtle, with a 0.02-0.03 rise over the spring hemisphere (200-500 mbar) perturbed by (i) low-fpf_p air advected by both the springtime storm of 2010 and equatorial upwelling; and (ii) subsidence of high-fpf_p air at northern high latitudes, responsible for a developing north-south asymmetry in fpf_p. Conversely, the shifting asymmetry in the para-H2_2 disequilibrium primarily reflects the changing temperature structure (and the equilibrium distribution of fpf_p), rather than actual changes in fpf_p induced by chemical conversion or transport. CIRS results interpolated to the same point in the seasonal cycle as re-analysed Voyager-1 observations show qualitative consistency, with the exception of the tropical tropopause near the equatorial zones and belts, where downward propagation of a cool temperature anomaly associated with Saturn's stratospheric oscillation could potentially perturb tropopause temperatures, para-H2_2 and winds. [ABRIDGED]Comment: Preprint accepted for publication in Icarus, 29 pages, 18 figure

    Introducing a virtual emergency operations center into a higher education curriculum

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    At West Texas A&M University, faculty members in the Criminal Justice and Emergency Management programs teach students how to deal with man-made and natural disasters. These program courses require students to learn about the National Incident Management Systems (NIMS) in addition to passing certain requirements. Each student must pass NIMS courses 100 and 200 as part of their coursework where students are given the opportunity to work through a table-top exercise involving a natural or man-made disaster. Over the past several years, due to the success of these exercises, one of the criminal justice professors proposed a funding project to create a classroom designed for crisis management exercises in the future. This article conveys important qualitative discussions in two significant areas: how the crisis management classroom was created, designed, and integrated into the emergency operations center for the Texas Panhandle; and how the crisis management classroom was provided with the opportunity to integrate a virtual emergency operations center (VEOCI), making West Texas A&M University the fifth university in the United States to have access to the new virtual management system

    The Origin of Nitrogen on Jupiter and Saturn from the 15^{15}N/14^{14}N Ratio

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    The Texas Echelon cross Echelle Spectrograph (TEXES), mounted on NASA's Infrared Telescope Facility (IRTF), was used to map mid-infrared ammonia absorption features on both Jupiter and Saturn in February 2013. Ammonia is the principle reservoir of nitrogen on the giant planets, and the ratio of isotopologues (15^{15}N/14^{14}N) can reveal insights into the molecular carrier (e.g., as N2_2 or NH3_3) of nitrogen to the forming protoplanets, and hence the source reservoirs from which these worlds accreted. We targeted two spectral intervals (900 and 960 cm1^{-1}) that were relatively clear of terrestrial atmospheric contamination and contained close features of 14^{14}NH3_3 and 15^{15}NH3_3, allowing us to derive the ratio from a single spectrum without ambiguity due to radiometric calibration (the primary source of uncertainty in this study). We present the first ground-based determination of Jupiter's 15^{15}N/14^{14}N ratio (in the range from 1.4×1031.4\times10^{-3} to 2.5×1032.5\times10^{-3}), which is consistent with both previous space-based studies and with the primordial value of the protosolar nebula. On Saturn, we present the first upper limit on the 15^{15}N/14^{14}N ratio of no larger than 2.0×1032.0\times10^{-3} for the 900-cm1^{-1} channel and a less stringent requirement that the ratio be no larger than 2.8×1032.8\times10^{-3} for the 960-cm1^{-1} channel (1σ1\sigma confidence). Specifically, the data rule out strong 15^{15}N-enrichments such as those observed in Titan's atmosphere and in cometary nitrogen compounds. To the extent possible with ground-based radiometric uncertainties, the saturnian and jovian 15^{15}N/14^{14}N ratios appear indistinguishable, implying that 15^{15}N-enriched ammonia ices could not have been a substantial contributor to the bulk nitrogen inventory of either planet, favouring the accretion of primordial N2_2 from the gas phase or as low-temperature ices.Comment: 33 pages, 19 figures, manuscript accepted for publication in Icaru

    Mid-Infrared Spectroscopy of Uranus from the Spitzer Infrared Spectrometer: 2. Determination of the Mean Composition of the Upper Troposphere and Stratosphere

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    Mid-infrared spectral observations Uranus acquired with the Infrared Spectrometer (IRS) on the Spitzer Space Telescope are used to determine the abundances of C2H2, C2H6, CH3C2H, C4H2, CO2, and tentatively CH3 on Uranus at the time of the 2007 equinox. For vertically uniform eddy diffusion coefficients in the range 2200-2600 cm2 s-1, photochemical models that reproduce the observed methane emission also predict C2H6 profiles that compare well with emission in the 11.6-12.5 micron wavelength region, where the nu9 band of C2H6 is prominent. Our nominal model with a uniform eddy diffusion coefficient Kzz = 2430 cm2 sec-1 and a CH4 tropopause mole fraction of 1.6x10-5 provides a good fit to other hydrocarbon emission features, such as those of C2H2 and C4H2, but the model profile for CH3C2H must be scaled by a factor of 0.43, suggesting that improvements are needed in the chemical reaction mechanism for C3Hx species. The nominal model is consistent with a CH3D/CH4 ratio of 3.0+-0.2x10-4. From the best-fit scaling of these photochemical-model profiles, we derive column abundances above the 10-mbar level of 4.5+01.1/-0.8 x 10+19 molecule-cm-2 for CH4, 6.2 +- 1.0 x 10+16 molecule-cm-2 for C2H2 (with a value 24% higher from a different longitudinal sampling), 3.1 +- 0.3 x 10+16 molecule-cm-2 for C2H6, 8.6 +- 2.6 x 10+13 molecule-cm-2 for CH3C2H, 1.8 +- 0.3 x 10+13 molecule-cm-2 for C4H2, and 1.7 +- 0.4 x 10+13 molecule-cm-2 for CO2 on Uranus. Our results have implications with respect to the influx rate of exogenic oxygen species and the production rate of stratospheric hazes on Uranus, as well as the C4H2 vapor pressure over C4H2 ice at low temperatures

    Biomimics of [FeFe]-hydrogenases with a pendant amine: Diphosphine complexes [Fe₂(CO)₄{μ-S(CH₂)nS}{κ²-(Ph₂PCH₂)₂NR}] (n = 2, 3; R = Me, Bn) towards H₂ oxidation catalysts

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    We report the synthesis and molecular structures of [FeFe]-ase biomimics [Fe2(CO)4{µ-S(CH2)nS}{κ2-(Ph2PCH2)2NR}] (1–4) (n = 2, 3; R = Me, Bn) and a comparative study of their protonation and redox chemistry, with the aim of assessing their activity as catalysts for H2 oxidation. They are prepared in good yields upon heating the hexacarbonyls and PCNCP ligands in toluene, a minor product of one reaction (n = 3, R = Bn) being pentacarbonyl [Fe2(CO)5(µ-pdt){Ph2PCH2N(H)Bn}] (5). Crystal structures show short Fe-Fe bonds (ca. 2.54 Å) with the diphosphine occupying basal-apical sites. Each undergoes a quasi-reversible one-electron oxidation and IR-SEC shows that this results in formation of a semi-bridging carbonyl. As has previously been observed, protonation products are solvent dependent, nitrogen being the favoured site of protonation site upon addition of one equivalent of HBF4.Et2O in d6-acetone, while hydride formation is favoured in CD2Cl2. However, the rate of N to Fe2 proton-transfer varies greatly with the nature of both the dithiolate-bridge and amine-substituent. Thus with NMe complexes (1–2) N-protonation is favoured in acetone affording a mixture of endo and exo isomers, while for NBn complexes (3–4) proton-transfer to afford the corresponding μ-hydride occurs in part (for 3 edt) or exclusively (for 4 pdt). In acetone, addition of a further equivalent of HBF4.Et2O generally does not lead to hydride formation, but in CD2Cl2 dications [Fe2(CO)4{µ-S(CH2)nS}(μ-H){κ2-(Ph2PCH2)2NHR}]2+ result, in which the diphosphine can adopt either dibasal or basal-apical positions. Proton-transfer from Fe2 to N has been previously identified as a required transformation for H2 oxidation, as has the accessibility of the all-terminal carbonyl isomer of cations [Fe2(CO)4{µ-S(CH2)nS}{κ2-(Ph2PCH2)2NR}]+. We have carried out a preliminary H2 oxidation study of 3, oxidation by Fc[BF4] in the presence of excess P(o-tolyl)3 affording [HP(o-tol)3][BF4], with a turnover of ca. 2.3 ± 0.1 mol of H2 consumed per mole of

    Addressing and Overcoming Barriers to E-Cigarette Use for Smoking Cessation in Pregnancy: A Qualitative Study.

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    E-cigarettes may have a role in supporting pregnant women who would otherwise smoke to stop smoking. The study aimed to understand pregnant women's vaping experiences, in particular how vaping to stop smoking is facilitated and how barriers to this are overcome. We conducted semi structured telephone interviews (n = 15) with pregnant or postpartum women who vaped during pregnancy, either exclusively (n = 10) or dual-used (n = 5) (smoked and vaped). Thematic analysis was used to analyse the interviews. Two themes emerged. First, 'facilitating beliefs': inherent beliefs that helped women overcome barriers to vaping. These included understanding the relative safety of vaping and economic gains compared with smoking and pregnancy being a motivator to stop smoking. Second, 'becoming a confident vaper': accumulating sufficient skill and confidence to comfortably vape. This included experimentation with e-cigarettes to ensure nicotine dependence and sensory needs were met. Seeking social support and employing strategies to address social stigma were also important. Positive beliefs about vaping and becoming proficient at vaping were viewed as ways to overcome barriers to vaping. The theoretical domain framework informed intervention recommendations to assist pregnant smokers who have tried but cannot stop smoking to switch to vaping

    Beneficial postprandial lipaemic effects of interrupting sedentary time with high-intensity physical activity versus a continuous moderate-intensity physical activity bout: a randomised crossover trial

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    Objectives To compare the postprandial cardiometabolic response to prolonged sitting, continuous moderate-intensity physical activity (PA) followed by prolonged sitting, and interrupting prolonged sitting with hourly high-intensity PA breaks. Design Three-condition randomised crossover trial. Methods Fourteen sedentary and inactive adults aged 29 ± 9 years took part in three, 8-h conditions: (1) prolonged sitting (SIT), (2) a continuous 30-min moderate-intensity PA bout followed by prolonged sitting (CONT-SIT), and (3) sitting interrupted hourly with 2 min 32 s high-intensity PA bouts (SIT-ACT). The treadmill PA in conditions 2 and 3 were matched for energy expenditure. Two standardised test meals were consumed during each condition. Incremental area under the curve (iAUC) for each 8-h condition was calculated for glucose, insulin, triglyceride, and high-density lipoprotein cholesterol (HDL-C) concentrations. Statistical analyses were completed using linear mixed models. Results Compared with SIT, SIT-ACT lowered triglyceride iAUC by 2.23 mmol/L ∙ 8 h (95% CI −4.33, −0.13) and raised HDL-C iAUC by 0.99 mmol/L ∙ 8 h (0.05, 1.93) (all p ≤ 0.038). There was no significant difference in triglyceride or HDL-C iAUC between CONT-SIT and SIT or SIT-ACT (p ≥ 0.211). There were no significant differences between conditions for glucose or insulin iAUC (p ≥ 0.504). Conclusions This study suggests that interrupting prolonged sitting with hourly high-intensity PA breaks acutely improves postprandial triglyceride and HDL-C concentrations compared with prolonged sitting, whereas a continuous moderate-intensity PA bout does not

    Moderate Resolution Spitzer Infrared Spectrograph (IRS) Observations of M, L, and T Dwarfs

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    We present 10 - 19 um moderate resolution spectra of ten M dwarfs, one L dwarf, and two T dwarf systems obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. The IRS allows us to examine molecular spectroscopic features/lines at moderate spectral resolution in a heretofore untapped wavelength regime. These R~600 spectra allow for a more detailed examination of clouds, non-equilibrium chemistry, as well as the molecular features of H2O, NH3, and other trace molecular species that are the hallmarks of these objects. A cloud-free model best fits our mid-infrared spectrum of the T1 dwarf epsilon Indi Ba, and we find that the NH3 feature in epsilon Indi Bb is best explained by a non-equilibrium abundance due to vertical transport in its atmosphere. We examined a set of objects (mostly M dwarfs) in multiple systems to look for evidence of emission features, which might indicate an atmospheric temperature inversion, as well as trace molecular species; however, we found no evidence of either.Comment: 19 pages, 7 figures, accepted ApJ 1/12/0
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