Estimation of night-time N2O5 concentrations from ambient NO2 and NO3 radical concentrations and the role of N2O5 in night-time chemistry

1986 ◽  
Vol 20 (2) ◽  
pp. 331-339 ◽  
Author(s):  
Roger Atkinson ◽  
Arthur M Winer ◽  
James N Pitts
Keyword(s):  
Night Time ◽  
No3 Radical

Feeding behaviour and bioerosion: the ecological role of the rock-boring urchin, Echinometra mathaei (de Blainville, 1825), in Okinawa reef flat

2013 ◽  
Vol 1 (1) ◽  
pp. 10
Author(s):  
Noar Muda Satyawan ◽  
Shelly Tutupoho ◽  
Yusli Wardiatno ◽  
Makoto Tsuchiya
Keyword(s):  
Feeding Behaviour ◽  
Reef Flat ◽  
Type A ◽  
Gut Contents ◽  
Biological Processes ◽  
Type B ◽  
Night Time ◽  
Echinometra Mathaei ◽  
Benthic Ecosystems

Erosion rate on corals due to activities of other biota is called bioerosion. The rock-boring urchin, Echinometra mathaei, when it is abundant, plays a significant role in benthic ecosystems, including biological processes like coral erosion. During feeding, E. mathaei erodes calcium carbonate besides grazing on algae living on coral, so it plays an important role in both organic and inorganic carbons in coral reefs. The urchin E. mathaei actively feeds during the night time (nocturnal grazer). Although in Okinawa four types (A-D) of the urchin exist, the research only focused on the types A and B. Type A of E. mathaei produced 0.44951 g feces per day on average while type B produced 0.38030 g feces per day. CaCO3 analysis in feces and gut contents showed bioerosion rate of E. mathaei type A was 0.64492 g/individu/day, and 0.54436 g/individu/day in type B. There were no significant differences in bioerosion impact of E. mathaei type A and B© Laju erosi pada karang yang disebabkan oleh biota, dikenal dengan bioerosi. Bulu babi jenis Echinometra mathaei, ketika melimpah, menjadi sangat berpengaruh terhadap ekosistem bentik termasuk proses biologi seperti erosi karang. Selama aktivitas makan, E. mathaei menggerus kalsium karbonat dalam proporsi yang besar di samping alga yang tumbuh menempel pada karang sehingga memiliki peran penting dalam siklus karbon organik dan anorganik di ekosistem terumbu karang. Bulu babi E. mathaei aktif mencari makan pada malam hari (nocturnal grazer). Meskipun di Okinanawa ada 4 tipe (A-D), pada eksperimen kali ini memfokuskan pada tipe A dan B saja. Tipe A E. mathaei rata-rata memproduksi 0,44951 g feses/hari dan tipe B memproduksi 0,38030 g feses/hari. Berdasarkan analisis CaCO3 yang dilakukan pada feses dan isi lambung, laju bioerosi yang disebabkan oleh E. mathaei tipe A sebesar 0,64492 g/individu/hari sedangkan tipe B sebesar 0,54436 g/individu/hari. Tidak terdapat perbedaan dampak bioerosi yang signifikan antara E. mathaei tipe A dan B©

Reciprocal Associations Between Adolescents’ Night-Time Sleep and Daytime Affect and the Role of Gender and Depressive Symptoms

2013 ◽  
Vol 44 (2) ◽  
pp. 556-569 ◽  
Author(s):  
Rinka M. P. van Zundert ◽  
Eeske van Roekel ◽  
Rutger C. M. E. Engels ◽  
Ron H. J. Scholte
Keyword(s):  
Depressive Symptoms ◽  
Night Time ◽  
Reciprocal Associations

scholarly journals Secondary organic aerosol production from modern diesel engine emissions

2009 ◽  
Vol 9 (4) ◽  
pp. 17665-17704 ◽  
Author(s):  
S. Samy ◽  
B. Zielinska
Keyword(s):  
Secondary Organic Aerosol ◽  
Dicarboxylic Acids ◽  
Transformation Products ◽  
Organic Aerosol ◽  
Engine Emissions ◽  
No3 Radical ◽  
Group Basis ◽  
Chamber Studies ◽  
The Impact

Abstract. Secondary organic aerosol (SOA) production was observed at significant levels in a series of modern diesel exhaust (DE) aging experiments conducted at the European Outdoor Photoreactor/Simulation Chamber (EUPHORE). The greatest production occurred in DE with toluene addition experiments (>40%), followed by DE with HCHO (for OH radical generation) experiments. A small amount of SOA (3%) was observed for DE in dark with N2O5 (for NO3 radical production) experiments. The analysis for a limited number (54) of polar organic compounds (POC) was conducted to assess the composition of modern DE and the formation of photochemical transformation products. Distinct POC formation in light versus dark experiments suggests the role of OH initiated reactions in these chamber atmospheres. A trend of increasing concentrations of dicarboxylic acids in light versus dark experiments was observed when evaluated on a compound group basis. The four toluene addition experiments in this study were performed at different [tol]o/[NOx]o ratios and displayed an average SOA% yield (in relation to toluene) of 5.3±1.6%, which is compared to past chamber studies that evaluated the impact of [tol]o/[NOx]o on SOA production in more simplified mixtures.

scholarly journals The role of lighting in road traffic collisions

2019 ◽  
Vol 52 (4) ◽  
pp. 485-494 ◽  
Author(s):  
P Raynham ◽  
J Unwin ◽  
M Khazova ◽  
S Tolia
Keyword(s):  
Road Traffic ◽  
Night Time ◽  
Initial Finding ◽  
Data Set ◽  
Solar Altitude ◽  
Time Period ◽  
Road Traffic Collision ◽  
Summer Time ◽  
Mean Time

The paper reports a study that examines how to determine if a road traffic collision took place in daylight or in the dark. An innovative method was developed, based on solar altitude, to establish cut-off points of daylight and darkness determined from a study of daylight availability in England, Scotland and Wales. This approach provides a rigorous method to differentiate daytime and night-time collisions. The criteria were used in a study of the collisions reported in the STATS19 data set for the weeks either side of the clock changes that are necessary between Greenwich Mean Time and British Summer Time. By comparing periods with the same clock time either side of the time change, using the aforementioned method, it was possible to isolate collisions within the same time period that during one week occurred in darkness and in the other week in daylight. The initial finding was that there are 19.3% more collisions in the dark periods and there is an even greater increase (31.7%) in pedestrian injuries.

scholarly journals Night-time Lookout Duty: The Role of Ambient Light Levels and Dark Adaptation

2012 ◽  
Vol 65 (4) ◽  
pp. 589-602 ◽  
Author(s):  
Tony Wynn ◽  
Peter A. Howarth ◽  
Bert R. Kunze
Keyword(s):  
Dark Adaptation ◽  
Probability Of Detection ◽  
Working Environment ◽  
Ambient Light ◽  
Night Time ◽  
Lighting Conditions ◽  
Light Levels ◽  
Ambient Lighting ◽  
Small Craft

The aim of this research was to clarify and quantify the demands of the working environment and watch-keeping regime for large commercial ships in relation to dark adaptation. The night lookout task requires the identification of the relatively bright navigational lights of other ships against the dark background of the sky and sea. The probability of detection is determined by the ambient lighting conditions on the bridge and the dark adapted state of vision. Light levels were such that threshold sensitivity (after 15 minutes) was reduced by around 2 log units in comparison to complete darkness. This has implications for the effective range of navigational lights at sea as defined in regulations. The intensity and position of navigation lights on larger vessels is such that the sensitivity of the eye under typical bridge conditions is likely to be sufficient for their visibility to be acceptable. This may not be the case for less well lit small craft.

scholarly journals Ionospheric conductivity effects on electrostatic field penetration into the ionosphere

2008 ◽  
Vol 8 (5) ◽  
pp. 1009-1017 ◽  
Author(s):  
V. V. Denisenko ◽  
M. Y. Boudjada ◽  
M. Horn ◽  
E. V. Pomozov ◽  
H. K. Biernat ◽  
...  
Keyword(s):  
Electric Field ◽  
Electrostatic Field ◽  
Night Time ◽  
Ionospheric Conductivity ◽  
Demeter Satellite ◽  
Classic Approach ◽  
Ionospheric Electric Field ◽  
Orbital Height ◽  
Field Penetration

Abstract. The classic approach to calculate the electrostatic field penetration, from the Earth's surface into the ionosphere, is to consider the following equation ∇·(σ·∇Φ)=0 where σ and Φ are the electric conductivity and the potential of the electric field, respectively. The penetration characteristics strongly depend on the conductivities of atmosphere and ionosphere. To estimate the electrostatic field penetration up to the orbital height of DEMETER satellite (about 700 km) the role of the ionosphere must be analyzed. It is done with help of a special upper boundary condition for the atmospheric electric field. In this paper, we investigate the influence of the ionospheric conductivity on the electrostatic field penetration from the Earth's surface into the ionosphere. We show that the magnitude of the ionospheric electric field penetrated from the ground is inverse proportional to the value of the ionospheric Pedersen conductance. So its typical value in day-time is about hundred times less than in night-time.

Sign in / Sign up

Export Citation Format

Share Document