Daytime Values Research Articles

Abstract P020: Associations of Markers of Inflammation with Nocturnal BP Dipping Status Using Two Common Dipping Definitions: the Genetic Epidemiology Network of Arteriopathy

Background: Compared to those with natural nocturnal blood pressure (BP) decreases, those lacking nocturnal BP decreases (“non-dippers”) are at greater risk of cardiovascular disease (CVD). Substantial evidence also supports a role of chronic systemic inflammation in the pathogenesis of CVD. The purpose of this study was to examine associations of markers of inflammation with two common definitions of BP dipping status using 24-hour ambulatory blood pressure (AMBP) readings. Methods: AMBP monitoring and assays of C-reactive protein (CRP), interleukin-6 (IL-6), e-selectin, tissue inhibitor of metalloproteinase-2 (TIMP-2), and a selection of thirteen other inflammatory-pathway biomarkers were performed in 722 participants (mean age 64 [range 42-83] years, 36% men, 39% black, 83% hypertensive) in the Genetic Epidemiology Network of Arteriopathy (GENOA) Study (2001-2004). Non-dippers were classified using two common definitions: (1) nocturnal systolic and diastolic BP both decreased by <10% compared to daytime values [“dual non-dippers”, n=161 (22%)], and (2) nocturnal SBP decreased by <10% [“systolic non-dippers”, n=380 (53%)]. Logistic regressions, fit with generalized estimating equations to account for sibship clustering, yielded odds ratios (OR) of dipping status for log-transformed inflammatory biomarkers, adjusted for age, race, and sex. Results: IL-6 (range 0-37 pg/ml) was associated with dual non-dipping status (OR=1.55 [95%CI: 1.03, 2.32] p=0.035), translating into a 55% increase in the likelihood of being a dual non-dipper for every approximate doubling of IL-6. IL-6 (OR=1.63 [1.13, 2.35] p=0.009) and CRP (OR=1.35 [1.08,1.68] p=0.008) overall, as well as e-selectin (OR=0.49 [0.28, 0.87] p=0.014) and TIMP-2 (OR=0.54 [0.30,0.98] p=0.041) in hypertensive subjects were associated with systolic non-dipping status. Conclusions: These results suggest that non-dipping classification should be approached with prudence, as the two different criteria may influence conclusions about predictive marker associations. In addition, markers involved in direct versus inhibitory inflammation pathways may operate differentially across patient subgroups. Our findings support the link between inflammation and non-dipping circadian BP patterns and provide novel information on markers and definitions which may be useful for early detection and subsequent prevention of CVD.

Prevalence of hypertension and circadian blood pressure variations in patients with obstructive sleep apnoea–hypopnoea syndrome

To investigate the prevalence of hypertension and circadian blood pressure (BP) variations in patients with obstructive sleep apnoea-hypopnoea syndrome (OSAHS). Patients referred to a sleep clinic underwent polysomnography with measurement of BP at four time points. They were classified into four groups (control, and mild, moderate or severe sleep apnoea) using the apnoea-hypopnoea index (AHI). Circadian variation was assessed using night-time to daytime mean BP (R(N/D)) and morning to evening mean BP (R(M/E)) ratios. Hypertension was significantly more common in patients with OSAHS (50.5%) than in controls (30.4%). AHI was positively correlated with hypertension after controlling for related confounders. Mean BP values at all four time points rose with increasing AHI. The increase in night-time and morning values was more pronounced than the increase in daytime and evening values in patients with OSAHS, resulting in loss of the normal BP diurnal rhythm. The R(N/D) and R(M/E) ratios increased with increasing AHI. Daytime BP was significantly correlated with AHI and the lowest oxygen saturation value. OSAHS was shown to be an independent risk factor for hypertension. It was also associated with loss of the normal BP diurnal rhythm.

Response to

updated, comprehensive and clear review of ambulatory blood pressure monitoring. The study is enriched by a number of recommendations regarding several practical issues, including why, when and how ordering, performing and interpreting an ambulatory blood pressure monitoring. Given that diurnal blood pressure variation is thought to be of clinical and prognostic relevance, it is not unexpected that the issue is dealt with in a long and detailed chapter. Yet, we were surprised that the different patterns of diurnal blood pressure variation as identified by ambulatory blood pressure monitoring are defined in an ambiguous way. In particular, the authors suggest that a normal diurnal pattern is present when ‘nocturnal blood pressure falls >10% of daytime values, or night–day blood pressure ratio is 0.8’,andsimilarstatementsareusedfordefining the other dipping patterns. However, no indication is found in the text or table (Box 9) as to which blood pressure component should be used for classifying a particular individual as having a normal, extreme, reduced blood pressure dipping or a nocturnal blood pressure rising. In the past, dipping patterns have been defined according to mean arterial pressure, systolic pressure, diastolic pressure or a combination of systolic and diastolic pressure, and this led to divergent classification of participants on the basis of which criterion is used. The issue is of considerable relevance, as the prognostic impact of night–day ratio is not the same when the definition is based on SBP or DBP [2,3]. The extent of percentage nocturnal reduction is on average greater for DBP than for SBP[4],and this may lead to serious problems of misclassification. It has also been suggested that the systolic night-to-day ratio may be similar in auscultatory and oscillometric recordings, whereas this could not be the case for the diastolic night-to-day ratio [5]. We feel that an elucidation of which blood pressure component(s) should be preferably used for defining the different dipping patterns is necessary in order to appreciate the important clinical implications of the study [1]. ACKNOWLEDGEMENTS

ACUTE MYOCARDIAL INFARCTION SPECIFICS IN PATIENTS WITH CHRONIC TONSILLITIS

Aim. To investigate the clinical specifics of acute myocardial infarction(AMI) in patients with chronic tonsillitis.Material and methods. The study included 70 patients at early AMI stages (Days 1–2). The following parameters were analysed: anthropometry, blood biochemistry, myocardial necrosis markers, QT interval dispersion, echocardiography and Holter ECG monitoring parameters, and a confirmed medical diagnosis of chronic tonsillitis in medical history.Results. In 31 patients with confirmed chronic tonsillitis, higher body mass index values, a significantly higher incidence of acute heart failure (19,4%; p<0,05) and anterior AMI (70%), higher glucose levels at admission (7,58±0,62 mmol/l), and a higher end-diastolic size of right ventriculum (3,04±0,19 cm vs. 2,66±0,05 cm) were observed. Mean daytime and peak nighttime heart rate values were higher than in other patients.Conclusion. Patients with confirmed chronic tonsillitis were characterised by a more severe clinical course of AMI. There is some evidence that chronic tonsillitis is also associated with metabolic syndrome.

Air breathing in Magadi tilapia Alcolapia grahami, under normoxic and hyperoxic conditions, and the association with sunlight and reactive oxygen species

Observations of the Magadi tilapia Alcolapia grahami in hot, highly alkaline Lake Magadi revealed that they air breathe not only during hypoxia, as described previously, but also during normoxia and hyperoxia. Air breathing under these latter conditions occurred within distinct groupings of fish (pods) and involved only a small proportion of the population. Air breathing properties (duration and frequency) were quantified from video footage. Air breathing within the population followed a diel pattern with the maximum extent of pod formation occurring in early afternoon. High levels of reactive oxygen species (ROS) in the water may be an irritant that encourages the air-breathing behaviour. The diel pattern of air breathing in the field and in experiments followed the diel pattern of ROS concentrations in the water which are amongst the highest reported in the literature (maximum daytime values of 2.53 – 8.10 μM H₂O₂). Interlamellar cell masses (ILCM) occurred between the gill lamellae of fish from the lagoon with highest ROS and highest oxygen levels, while fish from a normoxic lagoon with one third the ROS had little or no ILCM. This is the first record of air breathing in a facultative air-breathing fish in hyperoxic conditions and the first record of an ILCM in a cichlid species.

Long-term high-frequency validation of MODIS LST products in a Mediterranean mountain environment

The accuracy of Moderate-resolution Imaging Spectroradiometer (MODIS) level 3 1 km land surface temperature (LST) products was assessed through long-term validation carried out in a mountainous site in Sierra Nevada, southeast Spain. A total of 1458 day and night thermal images, acquired by Terra and Aqua satellites during 2008, were processed and compared to ground-truth data recorded at the meteorological station of Robledal de Cañar with a frequency of one measurement every 10 min. The purpose of this investigation was to understand whether MODIS LST data can be used as input for climate models to be constructed for mountainous environments. Several trends in the MODIS LST data were observed, including the underestimation of daytime values and the overestimation of night-time values. Although all the data sets (Terra and Aqua, diurnal and nocturnal) showed high correlation coefficients with ground measurements, only night values maintained a relatively high accuracy of approximately 2°C of annual average error. Factors that may cause errors in the MODIS LST data, like acquisition angle, cloud, and snow cover, were analysed without conclusive results. High accuracy levels, i.e. close to 1°C, similar to other validation studies carried out over simpler and much more homogenous land-cover types such as cultivated fields, have been achieved for night images acquired during the summer months, thus making these datasets reliable for their use in climatic models over mountainous regions.

Cross-hemisphere comparison of mid-latitude ionospheric variability during 1996–2009: Juliusruh vs. Hobart

Analysis of a long-time series of hourly median characteristics of the ionospheric plasma at two mid-latitude locations in the Northern and Southern hemisphere, Juliusruh (54.6N; 13.4E) and Hobart (42.9S; 147.3E), reveals patterns of their synchronous and independent variability. We studied timelines of GPS vTEC, ionogram-derived F2-layer peak electron density NmF2, ionospheric equivalent slab thickness τ, and their ratios at two locations during the complete 23rd solar cycle and its following period of the extremely low solar activity in 2008–2009. This study has also involved the comparative analysis of the observed data versus the model predictions by IRI-2012. During the high solar activity in 2000–2002, seasonal variations show a complicated cross-hemisphere behavior influenced by the winter and semi-annual anomalies, with the largest noon-time values of TEC and NmF2 observed around equinoxes. Strength of the winter anomaly in NmF2 was significantly greater at Juliusruh in comparison with Hobart. The winter anomaly in GPS vTEC values was much weaker than in NmF2 for the Northern hemisphere mid-latitudes and was entirely absent at the Southern hemisphere. Cross-hemisphere analysis of the equivalent slab thickness shows its clear seasonal dependence for all levels of solar activity: the day-time maximum τmax is observed during local summer, whereas the day-time minimum τmin is observed during local winter. The night-time values of τ were higher compared to the day-time values during the winter and equinox seasons. Comparative model-data study shows rather good IRI performance of the day-time NmF2 for mid-latitudes of both hemispheres and rather noticeable overestimations for the mid-night NmF2 values during high solar activity. Analysis of IRI vTEC demonstrates the model limitations, related with the absence of the plasmaspheric part, and actual demand in a reliable and standard ionosphere–plasmasphere model for analysis of GPS vTEC.

CMAQ modeling and analysis of radicals, radical precursors, and chemical transformations

AbstractAir quality simulations were performed for the Houston‐Galveston‐Brazoria area for springtime conditions in May and June of 2009. Meteorological parameters predicted by Weather Research and Forecasting (WRF) model, for which data assimilation with recursive objective analysis was performed, are well simulated most of the time. The Community Multiscale Air Quality (CMAQ) model driven by meteorology from WRF simulates ozone and many other trace species, including radical precursors such as HCHO and HONO, with a satisfactory agreement with observations. While CMAQ satisfactorily captures the daily variations of the OH radical, it sometimes underestimates its high daytime values. Concentrations of HO2 are often underpredicted in polluted air masses and persistently severely underpredicted at low NOx conditions, when the Houston air is affected by marine air masses. In contrast, concentrations of H2O2 and CH3OOH are almost always overpredicted by the model, the overprediction occurs frequently in the polluted air and occurs always when marine air is encountered. Those mispredictions are consistent despite day‐to‐day variations in meteorological conditions and emissions and bring into question current representation of radical‐related chemistry in the model as radical production and recirculation in the model is overtaken by termination processes and creation of more stable compounds, such as H2O2 and CH3OOH. Smaller model biases of H2O2 and peroxides are associated with lower humidity. The relative importance of various photolysis processes as radical sources in the Houston atmosphere was also elucidated. Morning HOx formation is dominated by HONO while ozone contributes the most during midday. HONO contribution to HOx formation is more pronounced at the surface layer where most of it is formed, radical production from ozone is more important at elevated levels where higher concentrations of ozone are observed. Formaldehyde contributes up to 40% and also peaks during midday, but on days when high morning concentrations of formaldehyde are observed, its contribution to HOx in the morning exceeds that of ozone. Photolysis of H2O2 is a minor contributor to radical levels.

Temporal and spatial variability of methane emissions in a northern temperate marsh

Although methane (CH4) fluxes from northern wetlands in Asia have been described in previous research at different temporal and spatial scales, integrated studies at the ecosystem scale were scarce. In this study, CH4 fluxes were measured using eddy covariance (EC) technique and the chamber method in a cool temperate marsh in northeast China during the growing season (May–September) of 2011. CH4 emissions were highly variable, both temporally and spatially during the measurement period. According to the EC observation data, CH4 fluxes showed a significant diurnal cycle during the mid-growing season with nighttime average flux about 67% of the average daytime values. Daily cumulative CH4 fluxes varied from 54 to 250 mg CH4 m−2 d−1 with an average flux of 136.2 mg CH4 m−2 d−1. The observations of chamber method showed that CH4 emissions differed markedly among the three main plant communities. Average flux at the Carex lasiocarpa site was about 4 times and 13.5 times of that at the Glyceria spiculosa site and Deyeuxia angustifolia site, respectively. The spatial variability of CH4 flux was mainly controlled by the varying water table level as well as the spatial distribution of different vascular plants, while the seasonal dynamic of CH4 emission could be best explained by the change of surface soil temperature and air pressure. A comparison was made between EC measurements and the upscaled chamber based model. The results from the model overestimated CH4 emission by 28% compared to the EC data. Considering the large variability of methane emission, it is necessary to conduct continuous observations on CH4 emission from northern wetlands at different temporal and spatial scales to comprehend the variability and also to predict responses to climate change.

The diurnal evolution of the urban heat island of Paris: a model-based case study during Summer 2006

Abstract. The urban heat island (UHI) over Paris during summer 2006 was simulated using the Advanced Regional Prediction System (ARPS) updated with a simple urban parametrization at a horizontal resolution of 1 km. Two integrations were performed, one with the urban land cover of Paris and another in which Paris was replaced by cropland. The focus is on a five-day clear-sky period, for which the UHI intensity reaches its maximum. The diurnal evolution of the UHI intensity was found to be adequately simulated for this five day period. The maximum difference at night in 2 m temperature between urban and rural areas stemming from the urban heating is reproduced with a relative error of less than 10%. The UHI has an ellipsoidal shape and stretches along the prevailing wind direction. The maximum UHI intensity of 6.1 K occurs at 23:00 UTC located 6 km downstream of the city centre and this largely remains during the whole night. An idealized one-column model study demonstrates that the nocturnal differential sensible heat flux, even though much smaller than its daytime value, is mainly responsible for the maximum UHI intensity. The reason for this nighttime maximum is that additional heat is only affecting a shallow layer of 150 m. An air uplift is explained by the synoptic east wind and a ramp upwind of the city centre, which leads to a considerable nocturnal adiabatic cooling over cropland. The idealized study demonstrates that the reduced vertical adiabatic cooling over the city compared to cropland induces an additional UHI build-up of 25%. The UHI and its vertical extent is affected by the boundary-layer stability, nocturnal low-level jet as well as radiative cooling. Therefore, improvements of representing these boundary-layer features in atmospheric models are important for UHI studies.

Mid-latitude anomalies in the diurnal variation of electron density in the ionosphere

The main morphological features of the F region of the mid-latitude ionosphere as obtained from Intercosmos-19 satellite measurements are presented. The causes of the anomalies in the diurnal variation of the electron density in certain longitudinal areas at the June and December solstice in the northern (Yakutsk anomaly) and southern (Weddell Sea anomaly (WSA)) hemispheres are determined. For both anomalies, the nighttime values of the critical frequency of the F2 layer, foF2, are higher than the daytime ones. Based on Intercosmos-19 satellite data, global maps of foF2 distribution for midday and midnight local time under high solar activity are drawn. Both anomalies occupy a large area in latitude and longitude, about 100° and 30°, respectively. The maximum difference between nighttime and daytime values of foF2 in the Yakutsk anomaly area reaches 1.0–1.5 MHz, smaller than that for the WSA (3.5–4.0 MHz). In the present work, these anomalies are reproduced with the help of a global self-consistent model of the thermosphere, ionosphere, and protonosphere (GSM TIP), and the mechanisms of their formation are preliminary investigated.

Prevalence of white coat hypertension in children and adolescents

Objective: The aim of this study was to assess the prevalence of white coat hypertension in children and adolescents Design and methods: A cross sectional study was carried out in 142 patients 82 boys and 60 girls aged 12-19 years mean 16,27±2,8. To all patients were performed office blood pressure measurement (BP), Ambulatory Blood Pressure Monitoring (ABPM) and echocardiography. White Coat Hypertension (WCH) was diagnosed when office blood pressure measurement were 95 th percentile > for sex and age or >140/90 for those >18 years, and systolic and diastolic daytime values obtained by ABPM were <95 th percentile for sex and age or <135/85 mm Hg for those >18 years. All patients after follow up one year were undergoing second ABPM Results: At baseline we detected 15 patients with white coat hypertension. This condition represented 56% of the office hypertension. The prevalence of WHC hypertension was higher in the males than females (14,5% Vs 5,7% p=0,03) The mean age was not different to normotensive and hypertensive groups (16,17±2,1 vs 16,20±2,2 years and 16,19±2.09). During follow up 6 of 15 patients become normotensive 6 developed sustained hypertension and 3 had persistent White coat hypertension When compared patients that became normotensive than patients that developed sustained hypertension and had persistent WHC had higher baseline office systolic BP (142,03±7,3 vs 131,2±4,3 p<0,001) higher baseline daytime ambulatory systolic BP 127,53±5,73 vs 120,33±4.63 p<0,05. Conclusion: Children and adolescents with white coat hypertension should be followed closely due to its tendency to developed sustained hypertension. Higher values of systolic blood pressure associated with the development of hypertension

Effect of naproxen and acetaminophen on blood pressure lowering by ramipril, valsartan and aliskiren in hypertensive patients

Background: Non-steroidal anti-inflammatory drugs (NSAIDs) are frequently used for reducing pain and other symptoms in osteoarthritis (OA). NSAIDs have been associated with an increase in blood pressure (BP) in both normotensive and hypertensive individuals and a blunting effect on various anti-hypertensive medications. Acetaminophen effects on anti-hypertensive treatment, instead, are still a matter of debate.Objectives: To assess the effect of naproxen versus acetaminophen on ramipril, valsartan and aliskiren therapy in hypertensive patients with OA in a double-blind, cross-over study, by measuring clinic, ambulatory BP and heart rate (HR).Results: One hundred seventy four patients were randomly treated with ramipril, valsartan or aliskiren for 8 weeks and 135 patients with normalized BP were randomized to receive naproxen or acetaminophen for 2 weeks. Naproxen significantly increased clinic and ambulatory systolic/diastolic BP (SBP/DBP) values in patients treated with ramipril (p < 0.01) or valsartan (p < 0.05), but did not affect aliskiren effects. Also acetaminophen slightly but significantly affected clinic and ambulatory SBP/DBP in all three groups and, surprisingly, it also produced a slight increase in HR (+3.1, +3.3 and +3.4 b/min day-time HR values, for ramipril, valsartan and aliskiren, respectively; p < 0.05).Conclusions: Both naproxen and acetaminophen can affect anti-hypertensive therapy with ramipril, valsartan or aliskiren with a different extent. When acetaminophen is chosen for OA management in subjects with hypertension, patients should be evaluated as carefully as when traditional NSAIDs are given.

Application of WRF/Chem-MADRID and WRF/Polyphemus in Europe – Part 2: Evaluation of chemical concentrations and sensitivity simulations

Abstract. An offline-coupled model (WRF/Polyphemus) and an online-coupled model (WRF/Chem-MADRID) are applied to simulate air quality in July 2001 at horizontal grid resolutions of 0.5° and 0.125° over Western Europe. The model performance is evaluated against available surface and satellite observations. The two models simulate different concentrations in terms of domainwide performance statistics, spatial distribution, temporal variations, and column abundance. WRF/Chem-MADRID at 0.5° gives higher values than WRF/Polyphemus for the domainwide mean and over polluted regions in Central and southern Europe for all surface concentrations and column variables except for the tropospheric ozone residual (TOR). Compared with observations, WRF/Polyphemus gives better statistical performance for daily HNO3, SO2, and NO2 at the European Monitoring and Evaluation Programme (EMEP) sites, maximum 1 h O3 at the AirBase sites, PM2.5 at the AirBase sites, maximum 8 h O3 and PM10 composition at all sites, column abundance of CO, NO2, TOR, and aerosol optical depth (AOD), whereas WRF/Chem-MADRID gives better statistical performance for NH3, hourly SO2, NO2, and O3 at the AirBase and BDQA (Base de données de la qualité de l'air) sites, maximum 1 h O3 at the BDQA and EMEP sites, and PM10 at all sites. WRF/Chem-MADRID generally reproduces well the observed high hourly concentrations of SO2 and NO2 at most sites except for extremely high episodes at a few sites, and WRF/Polyphemus performs well for hourly SO2 concentrations at most rural or background sites where pollutant levels are relatively low, but it underpredicts the observed hourly NO2 concentrations at most sites. Both models generally capture well the daytime maximum 8 h O3 concentrations and diurnal variations of O3 with more accurate peak daytime and minimal nighttime values by WRF/Chem-MADRID, but neither model reproduces extremely low nighttime O3 concentrations at several urban and suburban sites due to underpredictions of NOx and thus insufficient titration of O3 at night. WRF/Polyphemus gives more accurate concentrations of PM2.5, and WRF/Chem-MADRID reproduces better the observations of PM10 concentrations at all sites. The differences between model predictions and observations are mostly caused by inaccurate representations of emissions of gaseous precursors and primary PM species, as well as biases in the meteorological predictions. The differences in model predictions are caused by differences in the heights of the first model layers and thickness of each layer that affect vertical distributions of emissions, model treatments such as dry/wet deposition, heterogeneous chemistry, and aerosol and cloud, as well as model inputs such as emissions of soil dust and sea salt and chemical boundary conditions of CO and O3 used in both models. WRF/Chem-MADRID shows a higher sensitivity to grid resolution than WRF/Polyphemus at all sites. For both models, the use of a finer grid resolution generally leads to an overall better statistical performance for most variables, with greater spatial details and an overall better agreement in temporal variations and magnitudes at most sites. The use of online biogenic volatile organic compound (BVOC) emissions gives better statistical performance for hourly and maximum 8 h O3 and PM2.5 and generally better agreement with their observed temporal variations at most sites. Because it is an online model, WRF/Chem-MADRID offers the advantage of accounting for various feedbacks between meteorology and chemical species. However, this model comparison suggests that atmospheric pollutant concentrations are most sensitive in state-of-the-science air quality models to vertical structure, inputs, and parameterizations for dry/wet removal of gases and particles in the model.

Transcontinental methane measurements: Part 2. Mobile surface investigation of fossil fuel industrial fugitive emissions

The potent greenhouse gas, methane, CH4, has a wide variety of anthropogenic and natural sources. Fall, continental-scale (Florida to California) surface CH4 data were collected to investigate the importance of fossil fuel industrial (FFI) emissions in the South US. A total of 6600 measurements along 7020-km of roadways were made by flame ion detection gas chromatography onboard a nearly continuously moving recreational vehicle in 2010. A second, winter survey in Southern California measured CH4 at 2 Hz with a cavity ring-down spectrometer in 2012.Data revealed strong and persistent FFI CH4 sources associated with refining, oil/gas production, a presumed major pipeline leak, and a coal loading plant. Nocturnal CH4 mixing ratios tended to be higher than daytime values for similar sources, sometimes significantly, which was attributed to day/night meteorological differences, primarily changes in the boundary layer height. The highest CH4 mixing ratio (39 ppm) was observed near the Kern River Oil Field, California, which uses steam reinjection. FFI CH4 plume signatures were distinguished as stronger than other sources on local scales. On large (4°) scales, the CH4 trend was better matched spatially with FFI activity than wetland spatial patterns.Qualitative comparison of surface data with SCIAMACHY and GOSAT satellite retrievals showed agreement of the large-scale CH4 spatial patterns. Comparison with inventory models and seasonal winds suggests for some seasons and some portions of the Gulf of Mexico a non-negligible underestimation of FFI emissions. For other seasons and locations, qualitative interpretation is not feasible. Unambiguous quantitative source attribution is more complex, requiring transport modeling.

Seasonal measurements of OH, NOx, and J(O1D) at Mace Head, Ireland

Measurements of atmospheric OH concentrations were conducted between August 2010 and July 2011 at Mace Head showing maximum daytime values of 0.21 (±0.25) × 106 cm−3 in winter and 2.26 (±1.37) × 106 cm−3 in summer. Plots of OH versus ozone photolysis frequency, J(O1D), exhibited strong linear correlations with slopes of 1.06 (±0.05) × 1011 cm−3 s (R = 0.75) in clean marine air and 1.31 (±0.04) × 1011 cm−3 s (R = 0.79) in mixed marine/continental air. Surprisingly, no significant difference in the former correlation was found between low and high tide periods. NO and NO2 levels in air from the marine sector (190–300°) were typically below the detection limit (30 pptv and &lt;200 pptv, respectively). In the land sector, NO mixing ratios &lt;50 pptv dominated most of the time, suggesting that the atmospheric oxidation efficiency in this region is predominantly characterized by primary OH sources in a low NOx environment.

Transcontinental methane measurements: Part 1. A mobile surface platform for source investigations

The potent greenhouse gas, methane, CH4, originates from a wide range of anthropogenic and natural sources. A ground-based, satellite-scale, transcontinental (Florida to California) survey was conducted to understand better emissions from key sources including wetlands, forest fire, and geologic sources, as well as to acquire desert background values and lower atmosphere vertical profiling in the San Bernardino Mountains. A total of 6600 measurements along 7020 km of roadways were made by flame ion detection, gas chromatography (GC) onboard a recreational vehicle in 2010, and during a second survey with a cavity ring-down spectrometer system in Southern California in 2012. Significant vibration reduction efforts allowed near continuous mobile GC measurements.Nocturnal CH4 measurements tended to be higher compared to daytime values, sometime significantly, for similar sources and were concluded due to day/night meteorological differences. The lowest GC observations were 1.80 ppm, observed in the California desert, ∼60 ppb less than minimum desert CH4 observed in 2012. Thanks to smoke visualization of a brush fire plume, the flux from the fire was estimated at 0.15 kiloton day−1. Geologic CH4 emissions from the La Brea tar pit and surrounding areas were surprisingly strong, with peak concentrations of nearly 50 ppm and highly elevated CH4 concentrations extending over at least ∼100 km2, and accounting potentially for a significant fraction of the LA basin CH4 emissions. Geologic CO2 emissions also were observed.

Effect of circadian rhythm of blood pressure on arterial wall stiffness and on left ventricular diastolic dysfunction

Background Arterial stiffness is a risk factor for cardiovascular morbidity and mortality. Variability of blood pressure has been reported to be related to worse cardiovascular outcome. The relationship between the arterial stiffness and the circadian rhythm of blood pressure (BP) has been controversial. The objective was to the examine impacts of BP variability on left ventricular diastolic function and arterial stiffness in the hypertensive patients. Methods Ambulatory BP monitoring, pulse wave velocity, and echocardiography were performed in 268 patients (153 males, 47 ± 11 years) with HTN and pre-HTN. BP was measured at the outpatient clinic and 24-h ABPM was performed. Using carotid femoral applanation tonometry, PWA was performed for evaluation of systemic arterial stiffness expressed as augmentation index. Echocardiograms were performed and an average of 3–6 cardiac cycles was done for all measurements including the left ventricular mass index (LVMI), relative wall thickness (RWT), trans mitral flow propagation velocity (Vp), TDI, and midwall shortening fraction (MWSF). Nocturnal dipping was defined as a reduction of diastolic BP (DBP) by >10% of systolic BP (SBP) when compared with the daytime values. Isolated systolic nondipping, is reduction of Results Among groups, the clinic SBP and DBP, daytime mean BP of 24-h ABPM, gender and body mass index were not statistically different. Augmentation pressure (AP), augmentation index (AI) showed statistically significant difference ( p = 0.008 and 0.021, respectively). Multivariate analysis showed that isolated diastolic non-dipping was correlated with arterial stiffness expressed as AI only in young group.

NDVI e fluxo de CO2 em lavoura de soja no Rio Grande do Sul

O aumento das emissões dos gases de efeito estufa (GEE) se configura, atualmente, como um dos principais problemas ambientais, o que pode afetar significativamente as atividades humanas e os ecossistemas terrestres. Um dos principais GEE é o CO2, o qual tem sido emitido indiscriminadamente em função do estilo de vida atual, assim como pela intensificação das atividades agrícolas. Neste contexto, o objetivo da pesquisa foi estudar a relação entre o comportamento espectral da cultura de soja ao longo de seu ciclo de desenvolvimento, utilizando imagens NDVI (Normalized Difference Vegetation Index) e o fluxo de CO2, calculado pelo método de covariância de vórtices (eddy covariance), gerando informações e metodologia para investigar as trocas de carbono em uma área de cultivo de soja no estado do Rio Grande do Sul, durante a safra de 2008/2009. Utilizou-se imagens TM do satélite Landsat 5, dados fenológicos e dados coletados em estação micrometeorológica ao longo do ciclo de desenvolvimento da soja. Os resultados mostraram que o padrão temporal do fluxo de CO2 ao longo do dia é cíclico, sendo que no período diurno apresenta valores negativos (captura) e no período noturno, positivos (liberação). A radiação solar global determina a magnitude do aprisionamento de CO2 pela cultura da soja, mas o fluxo é modulado pelo estádio fenológico da cultura. A atividade fotossintética das plantas de soja é maior durante o estádio vegetativo, quando coincide a maior incidência de radiação solar e o maior aparato fotossintético. O NDVI, obtido de imagens Landsat, é um indicador da evolução da biomassa da soja ao longo do ciclo. Existe correlação entre o NDVI e o fluxo negativo de CO2 (captura), ocorridos no período diurno. Portanto, técnicas de sensoriamento remoto demonstram potencialidade na geração de informações úteis sobre as trocas de CO2 entre a superfície e a atmosfera.

Evaluating Cloud Contamination in Clear-Sky MODIS Terra Daytime Land Surface Temperatures Using Ground-Based Meteorology Station Observations

Abstract Environment Canada meteorological station hourly sampled air temperatures Tair at four stations in the southwest Yukon were used to identify cloud contamination in the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra clear-sky daytime land surface temperature (LST) and emissivity daily level-3 global 1-km grid product (MOD11A1, Collection 5) that is not flagged by the MODIS quality algorithm as contaminated. The additional cloud masking used qualitative ground-based sky condition observations, collected at two of the four stations, and coincident MODIS quality flag information. The results indicate that air temperature observed at a variety of discrete spatial locations having different land cover is highly correlated with MODIS LST collected at 1-km grid spacing. Quadratic relationships between LST and air temperature, constrained by ground observations of “clear” sky conditions, show less variability than relationships found under “mainly clear” and “mostly cloudy” sky conditions, and the more clouds observed in the sky coincides with a decreasing y intercept. Analysis of MODIS LST and its associated quality flags show a cold bias (&amp;lt;0°C) in the assignment of the ≤3-K-average LST error, indicating MODIS LST has a maximum average error of ≤2 K over a warm surface (&amp;gt;0°C). Analysis of two observation stations shows that unidentified clouds in MODIS LST are between 13% and 17%, a result that agrees well with previous studies. Analysis of daytime values is important because many processes are dependent on daylight and maximum temperature. The daytime clear-sky LST–Tair relationship observed for the good-quality confirmed cloud-free-sky MODIS LST quality flag can be used to discriminate cloud-contaminated grid cells beyond the standard MODIS cloud mask.