92 research outputs found
Atmospheric cycles of nitrogen oxides and ammonia
The atmospheric cycles of nitrogenous trace compounds for the Northern and Southern Hemispheres are discussed. Source strengths and destruction rates for the nitrogen oxides: NO, NO2 and HNO3 -(NOX) and ammonia (NH3) are given as a function of latitude over continents and oceans. The global amounts of NOX-N and NH3-N produced annually in the period 1950 to 1975 (34 + 5 x one trillion g NOx-N/yr and 29 + or - 6 x one trillion g NH3-N/yr) are much less than previously assumed. Globally, natural and anthropogenic emissions are of similar magnitude. The NOx emission from anthropogenic sources is 1.5 times that from natural processes in the Northern Hemisphere, whereas in the Southern Hemisphere, it is a factor of 3 or 4 less. More than 80% of atmospheric ammonia seems to be derived from excrements of domestic animals, mostly by bulk deposition: 24 + or - 9 x one trillion g NO3 -N/yr and 21 + or - 9 x one trillion g NH4+-N/yr. Another fraction may be removed by absorption on vegetation and soils
INTERSEPSI HUJAN DAN PENGARUHNYA TERHADAP PEMINDAHAN ENERGI DAN MASSA PADA HUTAN TROPIKA BASAH ” STUDI KASUS TAMAN NASIONAL LORE LINDU”
The field observation of this research was conducted from June 2005 – May 2007 in tropical rainforest at Lore Lindu National Park Central Sulawesi. The main objectives of this research were to study (i) the relationships between interception loss and rainfall properties and vegetation characters and to determine the dominant factors affected (ii) the effect of rainfall interception on energy flux and mass transfer and (iii) the dynamics of vertical energy flux under the forest and grass land. Rainfall interception was 36.34 % of gross rainfall in 200 events, Depth rainfall and LAI factors had strong effects on rainfall interception. The relationships could be expressed as Ic = 0.980+0.239P+0.035LAI (R2 = 0.78). The output of this equation was compared with Gash model and the observation value showed that deviation of the equation was 1 % and less than Gash model, so that equation gave as good result as Gash model gave. By considering the data requirements and calculation procedures it was concluded that this equation is applicable for interception prediction. Land use type had effects on radiative and energy balance. Net radiation (Rn) in the forest was 10.66 MJ/m2/day and higher than in the grass land where incident global radiation was similar. Vertical latent heat flux in the forest was 9.53 MJ/m2/day or 89.40% Rn in rainy day and 8.41 MJ/m2/day or 74.56 % Rn in dry day, on the other hand, in the grass land, sensible heat flux was higher than latent heat flux of all weather condition. Direct effect of rainfall interception on energy flux and mass transfer might be described that is needed latent heat 9.0 MJ/m2/rainy day to evaporate the rain intercepted of 3.69 mm/rainy day. Effect of rainfall interception had positive correlation with latent heat flux and the negative correlation with sensible heat flux.
Response of CO<sub>2</sub> and H<sub>2</sub>O fluxes in a mountainous tropical rainforest in equatorial Indonesia to El Niño events
The possible impact of El Niño–Southern Oscillation (ENSO) events on the
main components of CO<sub>2</sub> and H<sub>2</sub>O fluxes between the tropical rainforest
and the atmosphere is investigated. The fluxes were continuously measured in an
old-growth mountainous tropical rainforest in Central Sulawesi in
Indonesia using the eddy covariance method for the period from January 2004
to June 2008. During this period, two episodes of El Niño and one
episode of La Niña were observed. All these ENSO episodes had moderate
intensity and were of the central Pacific type. The temporal variability
analysis of the main meteorological parameters and components of CO<sub>2</sub>
and H<sub>2</sub>O exchange showed a high sensitivity of evapotranspiration (ET)
and gross primary production (GPP) of the tropical rainforest to
meteorological variations caused by both El Niño and La Niña
episodes. Incoming solar radiation is the main governing factor that is
responsible for ET and GPP variability. Ecosystem respiration (RE) dynamics
depend mainly on the air temperature changes and are almost insensitive to
ENSO. Changes in precipitation due to moderate ENSO events did not have any
notable effect on ET and GPP, mainly because of sufficient soil moisture
conditions even in periods of an anomalous reduction in precipitation in the
region
Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease
Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.
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