365 research outputs found
In Situ Coral Reef Oxygen Metabolism: An Eddy Correlation Study
Quantitative studies of coral reefs are challenged by the three-dimensional hard structure of reefs and the high spatial variability and temporal dynamics of their metabolism. We used the non-invasive eddy correlation technique to examine respiration and photosynthesis rates, through O-2 fluxes, from reef crests and reef slopes in the Florida Keys, USA. We assessed how the photosynthesis and respiration of different reef habitats is controlled by light and hydrodynamics. Numerous fluxes (over a 0.25 h period) were as high as 4500 mmol O-2 m(-2) d(-1), which can only be explained by efficient light utilization by the phototrophic community and the complex canopy structure of the reef, having a many-fold larger surface area than its horizontal projection. Over diel cycles, the reef crest was net autotrophic, whereas on the reef slope oxygen production and respiration were balanced. The autotrophic nature of the shallow reef crests implies that the export of organics is an important source of primary production for the larger area. Net oxygen production on the reef crest was proportional to the light intensity, up to 1750 mu mol photons m(-2) s(-1) an d decreased thereafter as respiration was stimulated by high current velocities coincident with peak light levels. Nighttime respiration rates were also stimulated by the current velocity, through enhanced ventilation of the porous framework of the reef. Respiration rates were the highest directly after sunset, and then decreased during the night suggesting that highly labile photosynthates produced during the day fueled early-night respiration. The reef framework was also important to the acquisition of nutrients as the ambient nitrogen stock in the water had sufficient capacity to support these high production rates across the entire reef width. These direct measurements of complex reefs systems yielded high metabolic rates and dynamics that can only be determined through in situ, high temporal resolution measurements
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Experimental Physics and Industrial Control System (EPICS): Application source/release control for EPICS R3.11.6
This manual describes a set of tools that can be used to develop software for EPICS based control systems. It provides the following features: Multiple applications; the entire system is composed of an arbitrary number of applications: Source/Release Control; all files created or modified by the applications developers can be put under sccs (a UNIX Source/Release control utility): Multiple Developers; it allows a number of applications developers to work separately during the development phase but combine their applications for system testing and for a production system; Makefiles: makefiles are provided to automatically rebuild various application components. For C and state notation programs, Imagefiles are provided
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EPICS application source/release control
This manual describes a set of Application Source/Release Control tools (appSR) that can be used to develop software for EPICS based control systems. The Application Source/Release Control System (appSR) has been unbundled from base EPICS and is now available as an EPICS extension. Due to this unbundling, two new directories must be added to a user`s path (see section ``Environment`` on page 3 for more information) and a new command getapp must be issued after the getrel command to get a specific version of appSR (see section ``Creating The Initial Application System Area`` on page 7 for more information). It is now required that GNU make version 3.71 or later be used for makes instead of SUN make. Users should now type gmake instead of make
Hacia una pedagogía como teoría crítica en la formación de profesores en Ciencias de la Educación
El presente trabajo parte de la siguiente pregunta: ¿Qué lugar ocupa hoy y cuál debería ocupar la Pedagogía en la formación de profesores en Ciencias de la Educación?; y en la búsqueda de una respuesta a esta pregunta surge a posteriori: ¿Se puede pensar la pedagogía como teoría crítica frente a las ciencias de la educación (entendidas como ciencias que producen “Teoría Tradicional”)? Porque si esto fuera así los pedagogos tendríamos la responsabilidad de pensar una teoría de la educación de carácter emancipatorio para poder replantear la cuestión de “¿Hacia dónde va la educación?” Es decir, si la pedagogía es un saber y una reflexión sobre la práctica, debemos poder producir un saber que sea emancipatorio y propositivo que nos permita decir como apuntar al objetivo de la igualdad en la escuela. Es fundamental replantear en la formación de profesionales de la educación ¿Qué es lo que hacemos como educadores?, ¿Qué sentido tiene nuestro trabajo docente? ¿Para qué educar hoy? Habría que repensar el rol de la pedagogía posicionándola como teoría crítica en la formación de profesores en Ciencias de la Educación, teniendo en cuenta este marco actual que se nos presenta.Facultad de Humanidades y Ciencias de la Educació
Summertime Influences of Tidal Energy Advection on the Surface Energy Balance in a Mangrove Forest
Mangrove forests are ecosystems susceptible to changing water levels and temperatures due to climate change as well as perturbations resulting from tropical storms. Numerical models can be used to project mangrove forest responses to regional and global environmental changes, and the reliability of these models depends on surface energy balance closure. However, for tidal ecosystems, the surface energy balance is complex because the energy transport associated with tidal activity remains poorly understood. This study aimed to quantify impacts of tidal flows on energy dynamics within a mangrove ecosystem. To address the research objective, an intensive 10-day study was conducted in a mangrove forest located along the Shark River in the Everglades National Park, FL, USA. Forest–atmosphere turbulent exchanges of energy were quantified with an eddy covariance system installed on a 30-m-tall flux tower. Energy transport associated with tidal activity was calculated based on a coupled mass and energy balance approach. The mass balance included tidal flows and accumulation of water on the forest floor. The energy balance included temporal changes in enthalpy, resulting from tidal flows and temperature changes in the water column. By serving as a net sink or a source of available energy, flood waters reduced the impact of high radiational loads on the mangrove forest. Also, the regression slope of available energy versus sink terms increased from 0.730 to 0.754 and from 0.798 to 0.857, including total enthalpy change in the water column in the surface energy balance for 30-min periods and daily daytime sums, respectively. Results indicated that tidal inundation provides an important mechanism for heat removal and that tidal exchange should be considered in surface energy budgets of coastal ecosystems. Results also demonstrated the importance of including tidal energy advection in mangrove biophysical models that are used for predicting ecosystem response to changing climate and regional freshwater management practices
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Genetically Elevated Fetuin-A Levels, Fasting Glucose Levels, and Risk of Type 2 Diabetes: The Cardiovascular Health Study*
OBJECTIVE Fetuin-A levels are associated with higher risk of type 2 diabetes, but it is unknown if the association is causal. We investigated common (>5%) genetic variants in the fetuin-A gene (AHSG) fetuin-A levels, fasting glucose, and risk of type 2 diabetes. RESEARCH DESIGN AND METHODS Genetic variation, fetuin-A levels, and fasting glucose were assessed in 2,893 Caucasian and 542 African American community-living individuals 65 years of age or older in 1992–1993. RESULTS Common AHSG variants (rs4917 and rs2248690) were strongly associated with fetuin-A concentrations (P < 0.0001). In analyses of 259 incident cases of type 2 diabetes, the single nucleotide polymorphisms (SNPs) were not associated with diabetes risk during follow-up and similar null associations were observed when 579 prevalent cases were included. As expected, higher fetuin-A levels were associated with higher fasting glucose concentrations (1.9 mg/dL [95% CI, 1.2–2.7] higher per SD in Caucasians), but Mendelian randomization analyses using both SNPs as unbiased proxies for measured fetuin-A did not support an association between genetically predicted fetuin-A levels and fasting glucose (−0.3 mg/dL [95% CI, −1.9 to 1.3] lower per SD in Caucasians). The difference between the associations of fasting glucose with actual and genetically predicted fetuin-A level was statistically significant (P = 0.001). Results among the smaller sample of African Americans trended in similar directions but were statistically insignificant. CONCLUSIONS Common variants in the AHSG gene are strongly associated with plasma fetuin-A concentrations, but not with risk of type 2 diabetes or glucose concentrations, raising the possibility that the association between fetuin-A and type 2 diabetes may not be causal
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Total and High-Molecular-Weight Adiponectin and Risk of Incident Diabetes in Older People
OBJECTIVE To delineate the associations of total adiponectin, high-molecular-weight (HMW) adiponectin, and the HMW-to-total adiponectin ratio with diabetes in older adults. RESEARCH DESIGN AND METHODS Total and HMW adiponectin were measured in a population-based study of older adults. The relations of total adiponectin, HMW adiponectin, and their ratio with incident diabetes (n = 309) were assessed in 3,802 individuals. RESULTS Total and HMW adiponectin were highly correlated (r = 0.94). Analysis using cubic splines revealed that the associations between total and HMW adiponectin and new-onset diabetes were not linear. Specifically, after adjustment for confounders, there were similar inverse relationships for total (hazard ratio per SD 0.49 [95% CI 0.39–0.63]) and HMW adiponectin (0.42 [0.32–0.56]) with diabetes up to values of 20 and 10 mg/L, respectively, above which the associations plateaued. These associations persisted after adjustment for potential mediators (blood pressure, lipids, C-reactive protein, and homeostasis model assessment of insulin resistance [HOMA-IR]). There was, however, evidence of interaction by HOMA-IR in the lower range of adiponectin, with stronger inverse associations among insulin-sensitive than insulin-resistant participants. HMW-to-total adiponectin ratio showed a linear adjusted association with outcome, but this was abolished by inclusion of mediating variables. CONCLUSIONS In this older cohort, increasing concentrations of total and HMW adiponectin were associated with comparably lower risks of diabetes, but these associations leveled off with further increases above concentrations of 20 and 10 mg/L, respectively. The more pronounced risk decreases at the lower range among participants without insulin resistance support a role for adiponectin that is independent of baseline hyperinsulinemia, but this will require further investigation
Nitrogen uptake and internal recycling in Zostera marina exposed to oyster farming: eelgrass potential as a natural biofilter
Oyster farming in estuaries and coastal lagoons frequently overlaps with the distribution of seagrass meadows, yet there are few studies on how this aquaculture practice affects seagrass physiology. We compared in situ nitrogen uptake and the productivity of Zostera marina shoots growing near off-bottom longlines and at a site not affected by oyster farming in San Quintin Bay, a coastal lagoon in Baja California, Mexico. We used benthic chambers to measure leaf NH4 (+) uptake capacities by pulse labeling with (NH4)-N-15 (+) and plant photosynthesis and respiration. The internal N-15 resorption/recycling was measured in shoots 2 weeks after incubations. The natural isotopic composition of eelgrass tissues and vegetative descriptors were also examined. Plants growing at the oyster farming site showed a higher leaf NH4 (+) uptake rate (33.1 mmol NH4 (+) m(-2) day(-1)) relative to those not exposed to oyster cultures (25.6 mmol NH4 (+) m(-2) day(-1)). We calculated that an eelgrass meadow of 15-16 ha (which represents only about 3-4 % of the subtidal eelgrass meadow cover in the western arm of the lagoon) can potentially incorporate the total amount of NH4 (+) excreted by oysters (similar to 5.2 x 10(6) mmol NH4 (+) day(-1)). This highlights the potential of eelgrass to act as a natural biofilter for the NH4 (+) produced by oyster farming. Shoots exposed to oysters were more efficient in re-utilizing the internal N-15 into the growth of new leaf tissues or to translocate it to belowground tissues. Photosynthetic rates were greater in shoots exposed to oysters, which is consistent with higher NH4 (+) uptake and less negative delta C-13 values. Vegetative production (shoot size, leaf growth) was also higher in these shoots. Aboveground/belowground biomass ratio was lower in eelgrass beds not directly influenced by oyster farms, likely related to the higher investment in belowground biomass to incorporate sedimentary nutrients
Comparison of two doses and two routes of administration of misoprostol after pre-treatment with mifepristone for early pregnancy termination
<p>Abstract</p> <p>Background</p> <p>It is not known whether a 400 μg dose of misoprostol has a similar efficacy as an 800 μg dose when administered sublingually or vaginally 24 hours after 200 mg mifepristone.</p> <p>Methods</p> <p>It is proposed to undertake a placebo-controlled, randomized, non-inferiority trial (3% margin of equivalence) of the two misoprostol doses when administered sublingually or vaginally using factorial design. A total of 3008 pregnant women (< 63 days of gestational age) who request legal termination of pregnancy will be recruited for the trial at 16 clinics in ten countries providing abortion services. Eligible women willing to join the study will be allocated randomly to one of the four treatment groups within each centre. Women in all treatment groups will first receive 200 mg mifepristone, followed 24 hours later by either 400 μg or 800 μg misoprostol, administered either sublingually or vaginally. The dose and route of administration of misoprostol will be blinded to women, each woman receiving four tablets vaginally and four tablets sublingually, two or four of which are 200 μg tablets of misoprostol and the rest are placebo tablets.</p> <p>The four treatment regimens will be compared in terms of: (i) their efficacy to induce complete abortion; (ii) induction-to-abortion interval when possible; (iii) the frequency of side effects; and (iv) women's perceptions. The initial judgment of the outcome of treatment is made at the follow-up visit on day 15 of the study and the final assessment four weeks later. It is estimated that the clinical phase will require 12–14 months for data collection.</p> <p>To compare the two routes and two doses, relative risks (RR) of failure to achieve a complete abortion and failure to terminate pregnancy and the two-sided 95% CIs will be calculated by standard methods, as well as risk differences and two-sided 95% CIs. The latter will be used to test the non-inferiority hypotheses (at 2.5% level of significance) for achieving complete abortion. The factorial structure will be taken into account in the analysis after testing the interaction.</p> <p>Trial registration</p> <p>ISRCTN87811512</p
Does size matter? A randomized controlled trial to assess the impact of external diameter on adherence to 3 different intravaginal rings among 24 US couples
Background: Intravaginal rings (IVRs) are being developed as multipurpose prevention technologies (MPTs) for simultaneous HIV and pregnancy prevention. However, no empirical data exists to support the current 54-58mm size as ideal. Understanding the impact of IVR size on adherence is critical for developing a product that can be used correctly and consistently. Methods: We conducted a randomized, open-label, 3-way crossover trial comparing adherence, preference, and acceptability of 3 non-medicated silicone IVRs of differing external diameters: 46mm, 56mm and 66mm. 24 couples in Atlanta, GA and Bronx, NY were randomized to the sequence of IVR use, used each continuously for ~30 days. The primary objective was to compare ring adherence, defined as never having the IVR out of the vagina for \u3e 30 minutes in 24h. Women reported occurrence and duration of expulsions and removals via daily text. We summarized the proportion of days the IVR was removed, expelled, or out all day, and the proportion of women adherent to each IVR. We used mixed methods logistic regression models with random intercepts (per participant) to compare the probability of each event happening per day of IVR use, per IVR. Results: 23/24 couples completed the study. 78%, 75% and 59% of participants were adherent to the IVRs of diameter 46mm, 56mm and 66mm respectively (Table 1). The 46mm and 66mm IVR performed similarly, with more expulsions and 24h outages for the 66mm IVR. When adjusting for size and sequence, women had \u3e 15 times the odds of the 66mm IVR being out all day versus the 56mm IVR (15.7, 95% CI: 3.4, 72.6). Conclusions: External diameter of these non-medicated IVRs had a significant impact on frequency of removal and expulsion. Product developers should prioritize IVRs in the range of 46mm-56mm
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