To see the other types of publications on this topic, follow the link: Relation n-aire.
Journal articles on the topic 'Relation n-aire'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Relation n-aire.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Bonetto, Fabienne. "Équilibres multiples et poids de l’histoire: Quelle responsabilité pour la politique économique?" Panoeconomicus 54, no. 2 (2007): 159–84. http://dx.doi.org/10.2298/pan0702159b.
Full textAbstract:
(francuski) En formalisant une dynamique ? effets de seuil, les mod?les ? ?quilibres multiples enrichissent le paradigme de la croissance endog?ne; l?objectif de cet article est de montrer qu?ils renforcent ?galement la responsabilit? de la politique ?conomique. En effet, d?s lors que les conditions initiales s?lectionnent l??quilibre de long terme, l?histoire de la politique publique d?investissement (au sens large) devient d?terminante. Par ailleurs l?intervention publique peut permettre la sortie de la trappe de pauvret?. Sur la p?riode 1970-1995, nous testons l?hypoth?se d?effets de seuil en liaison avec le niveau initial du stock de capital (au sens large) d?velopp? par l??tat. Nos r?sultats empiriques sugg?rent un r?le pour la politique publique dans la diff?renciation des r?gimes de convergence de sorte que la relation entre la croissance et la politique ?conomique n?est pas n?cessairement lin?aire.
2
Maciá Andreu, María José, Javier Sánchez-Sánchez, José Antonio García Córdoba, and Ana María Gallardo Guerrero. "Análisis de la seguridad y accesibilidad de los espacios deportivos en Educación Secundaria Obligatoria." Cuadernos de Psicología del Deporte 21, no. 1 (January 1, 2021): 242–57. http://dx.doi.org/10.6018/cpd.395671.
Full textAbstract:
Las instalaciones deportivas escolares son el marco idóneo donde los alumnos deben de adquirir los hábitos de actividad física, estableciendo el Real Decreto 132/2010, que estas deben de cumplir con las condiciones de seguridad y accesibilidad que determine la legislación vigente. No obstante, varias investigaciones previas alertan del incumplimiento de dichos requisitos, siendo el objetivo del presente estudio el análisis de aquellos relacionados con la seguridad y accesibilidad de los espacios deportivos utilizados para impartir las clases de Educación Física en la etapa de Educación Secundaria Obligatoria (ESO). La investigación se llevó a cabo en n=45 Institutos de ESO de titularidad pública de la Región de Murcia, a través de una observación in situ con dos listas de control ad hoc en función del espacio a analizar, de 71 ítems para espacios cubiertos y 36 ítems para espacios al aire libre, de respuesta dicotómica (SI/NO), elaboradas a partir de la normativa y legislación vigente. Los resultados muestran un porcentaje medio de cumplimiento del 63,05±7,09 en espacios cubiertos (n=51) y del 61,52±8,70 en espacios al aire libre (n=93) detectándose diferencias estadísticamente significativas en los cubiertos (p <0,05) en función de su titularidad, con un cumplimiento mayor en los municipales. Ninguno de los espacios deportivos analizados cumple con todos los requisitos establecidos, detectando numerosas deficiencias respecto a su seguridad que pueden conllevar riesgos, así como en relación a su accesibilidad, apreciando barreras arquitectónicas y un alto incumplimiento de los aspectos relacionados con la accesibilidad cognitiva y limitaciones de tipo visual. School sports facilities are the ideal framework where students must acquire physical activity habits, establishing Royal Decree 132/2010, that they must comply with the safety and accessibility conditions determined by current legislation. However, several previous research warn of non-compliance with these requirements, being the objective of this study the analysis of those related to the safety and accessibility of the sports facilities used in Physical Education classes at the compulsory secondary education stage. This research was carried out in n=45 compulsory secondary education schools of public ownership of the Region of Murcia, through an in situ observation with two ad hoc checklists according to the space to be analyzed, of 71 items for indoor facilities and 36 items for outdoor ones, of dichotomous response (YES/NO), developed from the current regulations and legislation. The results show an average percentage of compliance of 63.05±7.09 in indoor facilities (n=51) and 61.52±8.70 in outdoor spaces (n=93) detecting statistically significant differences in the indoor ones (p <0.05) depending on their ownership, with greater compliance in the municipal. None of the sports facilities analyzed meets all the established requirements, detecting numerous deficiencies regarding their safety that may entail risks, as well as in relation to their accessibility, appreciating architectural barriers and a high breach of the aspects related to cognitive accessibility and visual limitations. Le strutture sportive scolastiche sono il quadro ideale in cui gli studenti devono acquisire abitudini di attività fisica, stabilendo il regio decreto 132/2010, che deve rispettare le condizioni di sicurezza e accessibilità stabilite dalla normativa vigente. Tuttavia, diverse indagini precedenti avvertono della violazione di questi requisiti, essendo l'obiettivo del presente studio l'analisi di quelli relativi alla sicurezza e all'accessibilità degli spazi sportivi utilizzati per insegnare le lezioni di educazione fisica nell'istruzione secondaria obbligatoria (ESO). L'indagine è stata condotta in n=45 istituti ESO di proprietà pubblica della regione di Murcia, attraverso un'osservazione sistematica con due liste di controllo ad hoc a seconda dello spazio da analizzare, di 71 articoli per spazi coperti e 36 articoli per spazi esterni, risposta dicotomica (SÌ/NO), preparati dalle normative e dalla legislazione vigenti. I risultati mostrano una percentuale media di conformità di 63,05±7,09 negli spazi coperti (n=51) e 61,52±8,70 negli spazi esterni (n=93), rilevando differenze statisticamente significative negli spazi coperti (p <0,05) a seconda della proprietà, con una maggiore conformità nei comuni. Nessuna delle aree sportive analizzate soddisfa tutti i requisiti stabiliti, rilevando numerose carenze relative alla loro sicurezza che possono comportare rischi, nonché in relazione alla loro accessibilità, apprezzando le barriere architettoniche e un'alta violazione degli aspetti relativi all'accessibilità e alle limitazioni cognitive tipo visivo. As instalações esportivas escolares são a estrutura ideal onde os estudantes devem adquirir hábitos de atividade física, estabelecendo o Real Decreto 132/2010, que deve obedecer às condições de segurança e acessibilidade determinadas pela legislação vigente. No entanto, várias investigações anteriores alertam para a violação desses requisitos, sendo o objetivo do presente estudo a análise daqueles relacionados à segurança e acessibilidade dos espaços esportivos utilizados para o ensino das aulas de Educação Física no Ensino Médio obrigatório (ESO). A investigação foi realizada em n=45 institutos ESO de propriedade pública da Região de Múrcia, através de uma observação in situ com duas listas de verificação ad hoc, dependendo do espaço a ser analisado, de 71 itens para espaços cobertos e 36 itens para espaços ao ar livre, resposta dicotômica (SIM/NÃO), elaborado a partir da legislação e regulamentação vigentes. Os resultados mostram uma porcentagem média de conformidade de 63,05±7,09 nos espaços cobertos (n=51) e 61,52±8,70 nos espaços ao ar livre (n=93), sendo detectadas diferenças estatisticamente significantes (p <0,05) dependendo de sua propriedade, com maior conformidade nos municípios. Nenhuma das áreas de esportes analisadas atende a todos os requisitos estabelecidos, detectando inúmeras deficiências em relação à sua segurança que podem acarretar riscos, bem como em relação à sua acessibilidade, valorização de barreiras arquitetônicas e alta quebra de aspectos relacionados à acessibilidade cognitiva e limitações tipo visual.
3
Majima, Yuichi, Kazuhiko Takeuchi, Yukiyoshi Hamaguchi, Atsuhito Morishita, Keisuke Hirata, and Yasuo Sakakura. "Hearing Impairment in Relation to Viscoelasticity of Middle Ear Effusions in Children." Annals of Otology, Rhinology & Laryngology 97, no. 3 (May 1988): 272–74. http://dx.doi.org/10.1177/000348948809700311.
Full textAbstract:
Both dynamic viscosity (n′) and elasticity (G′) of middle ear effusion were measured with an oscillating sphere magnetic rheometer and compared with the degree of conductive hearing loss in 65 ears of 40 children. There was a significant correlation between n′ and the magnitude of the air-bone gap at 500 and 1,000 Hz, but there was no significant correlation between G′ and the magnitude of the air-bone gap at 2,000 or 4,000 Hz. No significant correlation was noted between G′ and the magnitude of the air-bone gap at 500,1,000, 2,000, or 4,000 Hz. These results indicate that the n′ of middle ear effusion has an effect on the amount of hearing impairment at frequencies below 1,000 Hz.
4
Karunaratne, K. C., and C. R. Burn. "Relations between air and surface temperature in discontinuous permafrost terrain near Mayo, Yukon Territory." Canadian Journal of Earth Sciences 41, no. 12 (December 1, 2004): 1437–51. http://dx.doi.org/10.1139/e04-082.
Full textAbstract:
The association of site characteristics with the n-factor, a ratio of air to ground surface temperature, was investigated at five sites in the boreal forest near Mayo, Yukon Territory. Permafrost was in equilibrium with surface conditions at three sites, was degrading at another, and was absent from the fifth. Air and near-surface ground temperatures were recorded by data loggers between September 2000 and April 2002, and mean daily temperatures were accumulated to calculate n-factors for the freezing (nf) and thawing (nt) seasons. Air temperature did not vary between the sites, so inter-site differences in nf and nt were because of variations in surface temperature. Variations in nf between the sites over the two winters were primarily because of differences in snow depth, but at sites with similar snow cover, the surface temperatures were relatively high when the site was underlain by unfrozen ground. During summer, daily mean surface temperatures were initially less than air temperatures. However, once the thawing front had penetrated below the depth of diurnal temperature fluctuation, the air and ground surface temperatures converged. Since the rate of thaw penetration is governed by soil thermal diffusivity, nt varies directly with this property. These results indicate that subsurface conditions, particularly absolute temperature and ground thermal properties, exert considerable influence on n-factors, and, at the Mayo sites, the influence is greater than that of the vegetation.
5
Frankel, Mika, Gabriel Bekö, Michael Timm, Sine Gustavsen, Erik Wind Hansen, and Anne Mette Madsen. "Seasonal Variations of Indoor Microbial Exposures and Their Relation to Temperature, Relative Humidity, and Air Exchange Rate." Applied and Environmental Microbiology 78, no. 23 (September 21, 2012): 8289–97. http://dx.doi.org/10.1128/aem.02069-12.
Full textAbstract:
ABSTRACTIndoor microbial exposure has been related to adverse pulmonary health effects. Exposure assessment is not standardized, and various factors may affect the measured exposure. The aim of this study was to investigate the seasonal variation of selected microbial exposures and their associations with temperature, relative humidity, and air exchange rates in Danish homes. Airborne inhalable dust was sampled in five Danish homes throughout the four seasons of 1 year (indoors,n= 127; outdoors,n= 37). Measurements included culturable fungi and bacteria, endotoxin,N-acetyl-beta-d-glucosaminidase, total inflammatory potential, particles (0.75 to 15 μm), temperature, relative humidity, and air exchange rates. Significant seasonal variation was found for all indoor microbial exposures, excluding endotoxin. Indoor fungi peaked in summer (median, 235 CFU/m3) and were lowest in winter (median, 26 CFU/m3). Indoor bacteria peaked in spring (median, 2,165 CFU/m3) and were lowest in summer (median, 240 CFU/m3). Concentrations of fungi were predominately higher outdoors than indoors, whereas bacteria, endotoxin, and inhalable dust concentrations were highest indoors. Bacteria and endotoxin correlated with the mass of inhalable dust and number of particles. Temperature and air exchange rates were positively associated with fungi andN-acetyl-beta-d-glucosaminidase and negatively with bacteria and the total inflammatory potential. Although temperature, relative humidity, and air exchange rates were significantly associated with several indoor microbial exposures, they could not fully explain the observed seasonal variations when tested in a mixed statistical model. In conclusion, the season significantly affects indoor microbial exposures, which are influenced by temperature, relative humidity, and air exchange rates.
6
Tremblay, Maryse. "Décisions rendues par le Conseil canadien des relations du travail." Articles 46, no. 1 (April 12, 2005): 204–14. http://dx.doi.org/10.7202/050651ar.
Full textAbstract:
Suite à la déréglementation dans le secteur du transport en 1987, Air Canada a voulu s'allier à des transporteurs régionaux en vue de combattre la concurrence. Elle a conclu des ententes avec eux et investi d'importantes sommes en vue de l'élaboration d'un réseau liaison. Face à cette nouvelle situation, l'Association internationale des machinistes et des travailleurs de l'aérospatiale, district n ° 148, agent négociateur actuel d'environ 8 000 employés d'Air Canada, a décidé d'adresser une demande au Conseil afin qu'il déclare qu'Air Canada, Air BC, Air Nova et Air Ontario constituent un employeur unique pour les fins du Code canadien du travail. Après avoir examiné les critères régissant la question de contrôle ou de la direction en commun des entreprises, le Conseil a décidé que les entreprises remplissaient les cinq critères requis, mais a refusé d'exercer son pouvoir discrétionnaire défaire une telle déclaration.
7
Tseng, C. M., C. S. Liu, and C. Lamborg. "Seasonal changes in gaseous elemental mercury in relation to monsoon cycling over the northern South China Sea." Atmospheric Chemistry and Physics 12, no. 16 (August 16, 2012): 7341–50. http://dx.doi.org/10.5194/acp-12-7341-2012.
Full textAbstract:
Abstract. The distribution of gaseous elemental mercury (GEM) was determined in the surface atmosphere of the northern South China Sea (SCS) during 12 SEATS cruises between May 2003 and December 2005. The sampling and analysis of GEM were performed on board ship by using an on-line mercury analyzer (GEMA). Distinct annual patterns were observed for the GEM with a winter maximum of 5.7 ± 0.2 ng m−3 (n = 3) and minimum in summer (2.8 ± 0.2; n = 3), with concentrations elevated 2–3 times global background values. Source tracking through backward air trajectory analysis demonstrated that during the northeast monsoon (winter), air masses came from Eurasia, bringing continental- and industrial-derived GEM to the SCS. In contrast, during summer southwest monsoon and inter-monsoon, air masses were from the Indochina Peninsula and Indian Ocean and west Pacific Ocean. This demonstrates the impact that long-range transport, as controlled by seasonal monsoons, has on the Hg atmospheric distribution and cycling in the SCS.
8
Ghaffar, Zulkifli Abdul, Salmiah Kasolang, Ahmad Hussein Abdul Hamid, and Mohd Syazwan Firdaus Mat Rashid. "Effect of Dimensionless Numbers on Air Core Diameter of Pressure-Swirl Atomizer." Applied Mechanics and Materials 899 (June 2020): 22–28. http://dx.doi.org/10.4028/www.scientific.net/amm.899.22.
Full textAbstract:
Air core is an important parameter in pressure swirl atomizer since formation of air core determines the thickness of the discharged liquid sheet and the effective flow area of nozzle discharge. This consequently will affect the coefficient of discharge and the spray angle. This study conducted for the investigation of the relation between dimensionless numbers on the air core diameter. Dimensionless numbers are helpful aid for the quantification of independent parameters involving atomizer design and operating conditions simultaneously. Reynolds number, Re and orifice-to-swirl chamber diameter ratio, N are the dimensionless numbers selected for this study. Despite of the availability of study on the effect of dimensionless numbers on air core diameter, more study requires especially for smaller N. An experimental test-rig was constructed to conduct the performance test of the atomizer. Acquired images were analyzed using image-processing software. It was found that N has more significant effect on the change of air core diameter compared to Re. However, it is observed that at Re = 40000, N = 0.07 produces almost similar air core diameter with N = 0.25 at Re < 20000. In contrast, with N = 0.5, air core diameter produces are larger even at Re < 20000. Hence, it can be concluded that both Re and N are important parameters in characterizing the air core diameter in pressure-swirl atomizer.
9
LI, Y. T., and R. WONG. "GLOBAL ASYMPTOTICS OF STIELTJES–WIGERT POLYNOMIALS." Analysis and Applications 11, no. 05 (September 2013): 1350028. http://dx.doi.org/10.1142/s0219530513500280.
Full textAbstract:
Asymptotic formulas are derived for the Stieltjes–Wigert polynomials Sn(z; q) in the complex plane as the degree n grows to infinity. One formula holds in any disc centered at the origin, and the other holds outside any smaller disc centered at the origin; the two regions together cover the whole plane. In each region, the q-Airy function Aq(z) is used as the approximant. For real x > 1/4, a limiting relation is also established between the q-Airy function Aq(x) and the ordinary Airy function Ai (x) as q → 1.
10
Tseng, C. M., C. S. Liu, and C. Lamborg. "Seasonal changes in gaseous elemental mercury in relation to monsoon cycling over the Northern South China Sea." Atmospheric Chemistry and Physics Discussions 12, no. 5 (May 11, 2012): 12203–27. http://dx.doi.org/10.5194/acpd-12-12203-2012.
Full textAbstract:
Abstract. The distribution of gaseous elemental mercury (GEM) was determined in the surface atmosphere of the Northern South China Sea (SCS) during 12 SEATS cruises between May 2003 and December 2005. The sampling and analysis of GEM were performed on board ship by using an on-line mercury analyzer (GEMA). Distinct annual patterns were observed for the GEM with a winter maximum of 5.7 ± 0.2 ng m−3 (n = 3) and low in summer (2.8 ± 0.2) (n = 3), with concentrations elevated 2 ∼ 3 times global background values. Source tracking through backward trajectory analysis demonstrated air masses during the northeast monsoon in winter came from Eurasia, bringing continental- and industrial-derived GEM to the SCS. In contrast, during summer southwest monsoon and inter-monsoon, air masses were from the Indochina peninsula and Indian Ocean and West Pacific Ocean. This demonstrates the impact that long-range transport, as controlled by seasonal monsoons, has on the Hg atmospheric distribution and cycling in the SCS.
11
Goia, Ioan Augustin. "Considerații privind potențialul identitar al arhitecturii rurale tradiționale." Anuarul Muzeului Etnograif al Transilvaniei 29 (December 20, 2015): 94–99. http://dx.doi.org/10.47802/amet.2015.29.07.
Full textAbstract:
L'auteur considère que le sentiment individuel d'appartenance à une communauté circonscrite spatialement et culturellement est généré par certains facteurs, qu'il énumère. Il remarque l'existence d'une tendance contemporaine d'attribuer à l'espace rural traditionnel un potentiel identitaire supérieur à l'espace urbain, parce que ce dernier a généré des valeurs culturelles semblables sur des aires beaucoup trop larges. La tendance mentionnée est générée, en principal, par l'existence, dans des espaces ruraux restreints, d'un certain rapport caractéristique, parfois unique, entre le paysage naturel et l'architecture ''organique'', rapport généré par des relations géographiques, sociales, économiques et culturelles distinctes. Vu que ce rapport se détériore au fur et à mesure i n s i t u, l'auteur considère que les musées ethnographiques en plein air, ont l'obligation de compléter les informations spécifiques du terrain, en fournissant aux visiteurs des repères culturels véridiques, à valeur identitaire réelle.
12
Van Dingenen, R., J. P. Putaud, S. Martins-Dos Santos, and F. Raes. "Physical aerosol properties and their relation to air mass origin at Monte Cimone (Italy) during the first MINATROC campaign." Atmospheric Chemistry and Physics 5, no. 8 (August 19, 2005): 2203–26. http://dx.doi.org/10.5194/acp-5-2203-2005.
Full textAbstract:
Abstract. Aerosol physical properties were measured at the Monte Cimone Observatory (Italy) from 1 June till 6 July 2000. The measurement site is located in the transition zone between the continental boundary layer and the free troposphere (FT), at the border between the Mediterranean area and Central Europe, and is exposed to a variety of air masses. Sub-μm number size distributions, aerosol hygroscopicity near 90% RH, refractory size distribution at 270°C and equivalent black carbon mass were continuously measured. Number size distributions and hygroscopic properties indicate that the site is exposed to aged continental air masses, however during daytime it is also affected by upslope winds. The mixing of this transported polluted boundary layer air masses with relatively clean FT air leads to frequent nucleation events around local noon. Night-time size distributions, including fine and coarse fractions for each air mass episode, have been parameterized by a 3-modal lognormal distribution. Number and volume concentrations in the sub-μm modes are strongly affected by the air mass origin, with highest levels in NW-European air masses, versus very clean, free tropospheric air coming from the N-European sector. During a brief but distinct dust episode, the coarse mode is clearly enhanced. The observed hygroscopic behavior of the aerosol is consistent with the chemical composition described by Putaud et al. (2004), but no closure between known chemical composition and measured hygroscopicity could be made because the hygroscopic properties of the water-soluble organic matter (WSOM) are not known. The data suggest that WSOM is slightly-to-moderately hygroscopic (hygroscopic growth factor GF at 90% relative humidity between 1.05 and 1.51), and that this property may well depend on the air mass origin and history. External mixing of aerosol particles is observed in all air masses through the occurrence of two hygroscopicity modes (average GF of 1.22 and 1.37, respectively). However, the presence of "less" hygroscopic particles has mostly such a low occurrence rate that the average growth factor distribution for each air mass sector actually appears as a single mode. This is not the case for the dust episode, where the external mixing between less hygroscopic and more hygroscopic particles is very prominent, and indicating clearly the occurrence of a dust accumulation mode, extending down to 50 nm particles, along with an anthropogenic pollution mode. The presented physical measurements finally allow us to provide a partitioning of the sub-μm aerosol in four non-overlapping fractions (soluble/volatile, non-soluble/volatile, refractory/non-black carbon, black carbon) which can be associated with separate groups of chemical compounds determined with chemical-analytical techniques (ions, non-water soluble organic matter, dust, elemental carbon). All air masses except the free-tropospheric N-European and Dust episodes show a similar composition within the uncertainty of the data (53%, 37%, 5% and 5% respectively for the four defined fractions). Compared to these sectors, the dust episode shows a clearly enhanced refractory-non-BC fraction (17%), attributed to dust in the accumulation mode, whereas for the very clean N-EUR sector, the total refractory fraction is 25%, of which 13% non-BC and 12% BC.
13
Zhang, Lin, and Zong Yu Chen. "The Relation between δ18O of Precipitation and Air Temperature in Northern China." Advanced Materials Research 233-235 (May 2011): 462–65. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.462.
Full textAbstract:
The relation between isotopic compositions of precipitation and surface air temperature provides an unique tool for paleoclimate studies. Ananysis was conducted of monthly and annual mean d18O content of precipitation and surface air temperature for spatial and a fixed location by using the the data of China (1985~2002) in Global Network of Isotopes in Precipitation (GNIP) Database.This study shows that there is a positive correlation between d18O of precipitation and surface air temperature for those stations whose latitude is higher than 34°~36°N. The seasonal d18O-temperature gradient derived from the monthly data of 12 stations in northern China is about 0.34‰°C-1. The d18O-temperature gradient, however, derived from the longterm annual mean data of 13 stations,, is about 0.52‰°C -1 which is substantially larger than the seasonal gradient. This longterm annual d18O-temperature gradient could be used as the isotope thermometer for palaeoclimate reconstruction in mid- and high-latitude regions in China.
14
Throop, Jennifer, Antoni G. Lewkowicz, and Sharon L. Smith. "Climate and ground temperature relations at sites across the continuous and discontinuous permafrost zones, northern Canada1This article is one of a series of papers published in this CJES Special Issue on the theme of Fundamental and applied research on permafrost in Canada.2Earth Science Sector (ESS) Contribution 20110128." Canadian Journal of Earth Sciences 49, no. 8 (August 2012): 865–76. http://dx.doi.org/10.1139/e11-075.
Full textAbstract:
Climate – ground temperature relations are examined under a range of conditions for 10 sites across northern Canada. The sites are located between 60°N and 83°N and at elevations of 40 to 1840 m above sea level. They encompass various environmental and climatic conditions, with permafrost temperatures that range from just below 0 to –15 °C. The substrates range from bedrock to fine-grained sediment with high ice content, and vegetation types include coniferous forests in the Mackenzie Valley, shrub tundra at high elevation in the southern Yukon Territory, and polar desert in the High Arctic. Permafrost conditions at all of these sites are determined primarily by air temperature, followed by snow and substrate conditions. The apparent thermal diffusivity is relatively high at colder sites and in bedrock and is lower at sites in sediment with high ice content. Snow has a greater influence on air–ground temperature relations at sites where mean annual air temperatures and active-layer moisture contents are relatively high, leading to physically significant latent heat effects and a slower freeze-back of the active layer.
15
Kampel-Furman, Liyona, Z. Joachims, H. Bar-Cohen, A. Grossman, Y. Frenkel-Nir, Y. Shapira, E. Alon, E. Carmon, and B. Gordon. "Hearing threshold shifts among military pilots of the Israeli Air Force." Journal of the Royal Army Medical Corps 164, no. 1 (September 6, 2017): 46–51. http://dx.doi.org/10.1136/jramc-2016-000758.
Full textAbstract:
BackgroundMilitary aviators are potentially at risk for developing noise-induced hearing loss. Whether ambient aircraft noise exposure causes hearing deficit beyond the changes attributed to natural ageing is debated. The aim of this research was to assess changes in hearing thresholds of Israeli Air Force (IAF) pilots over 20 years of military service and identify potential risk factors for hearing loss.MethodsA retrospective cohort analysis was conducted of pure-tone air conduction audiograms of pilots, from their recruitment at 18 years of age until the last documented medical check-up. Mean hearing thresholds were analysed in relation to age, total flight hours and aircraft platform. Comparisons were made to the hearing thresholds of air traffic controllers (ATCs) who were not exposed to the noise generated by aircraft while on duty.ResultsOne hundred and sixty-three pilots were included, with flying platforms ranging from fighter jets (n=54), combat helicopters (n=27), transport helicopters (n=52) and transport aircraft (n=30). These were compared with the results from 17 ATCs. A marked notch in the frequency range of 4–6 kHz was demonstrated in the mean audiograms of all platforms pilots, progressing with ageing. Hearing threshold shifts in relation to measurements at recruitment were first noted at the age of 30 years, particularly at 4 kHz (mean shift of 2.97 dB, p=0.001). There was no statistical association between flying variables and hearing thresholds adjusted for age by logistic regression analysis.ConclusionsThe audiometric profile of IAF pilots has a pattern compatible with noise exposure, as reflected by characteristic noise notch. However, no flight variable was associated with deterioration of hearing thresholds, and no significant difference from non-flying controls (ATCs) was seen.
16
Dakora, FD, and CA Atkins. "Diffusion of Oxygen in Relation to Structure and Function in Legume Root Nodules." Functional Plant Biology 16, no. 1 (1989): 131. http://dx.doi.org/10.1071/pp9890131.
Full textAbstract:
Although substantial rates of oxidative phosphorylation by bacteroids of Rhizobium are required to support sustained N2 fixation in legume nodules, the enzyme nitrogenase is extremely sensitive to oxygen. This apparent paradox indicates that nodules must exercise effective control over internal oxygen concentration. Structural features including lenticel development, the thickness and arrangement of cells and air spaces in the inner and outer cortex, the presence or completeness of the common endodermis as well as the distribution of infected cells, uninfected cells and air spaces in the nodule medulla are important to gaseous ventilation of the organ. Among these, the organisation of cells and water / gas- containing extracellular voids in the inner cortex bounding the infected medulla zone are critical components to overall diffusive resistance. These elements also appear to provide the means for the oper- ation of a reversible variable diffusion barrier to control gas movement. Inhibition of nodule functioning by a widely diverse range of factors, e. g. restricted H2O or photosynthate supply, exposure to acetylene or combined N, appears to be mediated through increased diffusion resistance.
17
Awan, Faraz Malik, Roberto Minerva, and Noel Crespi. "Improving Road Traffic Forecasting Using Air Pollution and Atmospheric Data: Experiments Based on LSTM Recurrent Neural Networks." Sensors 20, no. 13 (July 4, 2020): 3749. http://dx.doi.org/10.3390/s20133749.
Full textAbstract:
Traffic flow forecasting is one of the most important use cases related to smart cities. In addition to assisting traffic management authorities, traffic forecasting can help drivers to choose the best path to their destinations. Accurate traffic forecasting is a basic requirement for traffic management. We propose a traffic forecasting approach that utilizes air pollution and atmospheric parameters. Air pollution levels are often associated with traffic intensity, and much work is already available in which air pollution has been predicted using road traffic. However, to the best of our knowledge, an attempt to improve forecasting road traffic using air pollution and atmospheric parameters is not yet available in the literature. In our preliminary experiments, we found out the relation between traffic intensity, air pollution, and atmospheric parameters. Therefore, we believe that addition of air pollutants and atmospheric parameters can improve the traffic forecasting. Our method uses air pollution gases, including C O , N O , N O 2 , N O x , and O 3 . We chose these gases because they are associated with road traffic. Some atmospheric parameters, including pressure, temperature, wind direction, and wind speed have also been considered, as these parameters can play an important role in the dispersion of the above-mentioned gases. Data related to traffic flow, air pollution, and the atmosphere were collected from the open data portal of Madrid, Spain. The long short-term memory (LSTM) recurrent neural network (RNN) was used in this paper to perform traffic forecasting.
18
Yu, Rucong, and Jian Li. "Hourly Rainfall Changes in Response to Surface Air Temperature over Eastern Contiguous China." Journal of Climate 25, no. 19 (April 19, 2012): 6851–61. http://dx.doi.org/10.1175/jcli-d-11-00656.1.
Full textAbstract:
Abstract In this study, late-summer rainfall over eastern contiguous China is classified according to hourly intensity and the changes of moderate, intense, and extreme precipitation in response to variation of surface air temperature are analyzed. The e-folding decay intensity (Imi) derived from the exponential distribution of rainfall amount is defined as the threshold that partitions rainfall into moderate and intense rainfall, and the double e-folding decay intensity (Ie) is used as the threshold to pick out extreme cases. The mean values of Imi and Ie are about 12 and 24 mm h−1, respectively. Between the two periods, 1966–85 and 1986–2005, the ratio between moderate and intense rainfall has experienced significant changes. And the spatial pattern of changes in the percentage of moderate rainfall presents a direct relation with that of the surface air temperature. Based on temperature changes, three regimes, regime N (north China), regime C (central eastern China), and regime S (southeastern coastal area of China), are defined. In warming regimes (regimes N and S), the percentage of moderate rainfall exhibits a decreasing trend. In regime C, where the temperature has fallen, the percentage of moderate rainfall increased prominently. In all three regimes there are significant negative (positive) correlations between the percentage of moderate (intense) rainfall and the temperature. The relation between the extreme rainfall and the surface air temperature is far more regionally dependent. With plenty of water supply and little change in relative humidity, the extreme rainfall increased in regime S. Although regime N also shows strong warming trends, there is no significant trend in extreme precipitation due to the lack of water vapor transportation.
19
Karaca, Çiğdem Tepe, Erdoğan Gültekin, M. Kürşat Yelken, Ayşenur Akyıldız İğdem, and Mehmet Külekçi. "Long-Term Histologic Changes in Nasal Mucosa after Total Laryngectomy." International Journal of Otolaryngology 2010 (2010): 1–4. http://dx.doi.org/10.1155/2010/137128.
Full textAbstract:
Objective. To determine the long-term histopathologic changes in nasal mucosa and the relationship between progression of the histopathologic changes and the duration without air current stimulation.Material and Method. Biopsies were taken from the inferior turbinates of 11 laryngeal cancer patients after total laryngectomy. Specimens were stained with hematoksilen-eosin and several histopathologic parameters were examined under light microscopy.Results. All of the patients demonstrated at least one histopathologic abnormality (100%,n=11). Goblet destruction and stromal fibrosis were the most common findings (81%,n=9), followed by focal epithelial atrophy and subepithelial seromusinous gland destruction (45%,n=5), neovascularization and congestion (36%,n=4), complete epithelial atrophy and mixoid degeneration (27%,n=3). According to the duration between laryngectomy and biopsy, patients were grouped in to three: group 1; less than 12 months (36%,n=4), group 2; 12–36 months (18%,n=2), and group 3; more than 36 months (45%,n=5). Only congestion was found to be decreased as the duration increased (P<.005).Conclusion. In laryngeal cancer patients histopathologic changes occur in nasal mucosa eventuate due to the cessation of air current stimulation, however there was no relation between progression of the histopathologic findings and the duration of cessation.
20
Seneweera, Saman P., Oula Ghannoum, Jann P. Conroy, Ken Ishimaru, Masumi Okada, Mark Lieffering, Han Yong Kim, and Kazuhiko Kobayashi. "Changes in sourcesink relations during development influence photosynthetic acclimation of rice to free air CO2 enrichment (FACE)." Functional Plant Biology 29, no. 8 (2002): 947. http://dx.doi.org/10.1071/pp01250.
Full textAbstract:
Relationships between photosynthetic acclimation and changes in the balance between source-sink supply and demand of carbon (C) and nitrogen (N) were tested using rice (Oryza sativa L. cv. Akitakomachi). Plants were field-grown in northern Japan at ambient CO2 partial pressure [p(CO2)] or free air CO2 enrichment (FACE; p(CO2) ~ 26-32 Pa above ambient) with low, medium or high N supplies. Leaf CO2 assimilation rates (A) and biochemical parameters were measured at 32-36 (eighth leaf) and 76-80 (flag leaf) d after transplanting, representing stages with a contrasting balance between C and N supply and demand in sources and sinks. Acclimation due to FACE was pronounced in flag leaves at each N supply. This was not fully accounted for by reductions in leaf N concentrations, because A/N and Vcmax/N were lower in FACE-grown flag leaves. Acclimation did not occur in the eighth leaf, and A/N and Vcmax/N was not significantly increased in FACE-grown leaves. Soluble protein / sucrose and amino acid / sucrose concentrations decreased under FACE, whereas sucrose phosphate synthase protein levels increased. At flag leaf stage, there was a discrepancy between the demand and supply of N, which was resolved by enhanced leaf N remobilization, associated with the lower Rubisco concentrations under FACE. In contrast to the early growth stage, enhanced growth of rice plants was accompanied by increased plant N uptake in FACE. We conclude that photosynthetic acclimation in flag leaves occurs under FACE because there is a large demand for N for reproductive development, relative to supply of N from root uptake and remobilization from leaves.
21
Bubendorf, Alexandre, Stefan Walheim, Thomas Schimmel, and Ernst Meyer. "A robust AFM-based method for locally measuring the elasticity of samples." Beilstein Journal of Nanotechnology 9 (January 2, 2018): 1–10. http://dx.doi.org/10.3762/bjnano.9.1.
Full textAbstract:
Investigation of the local sample elasticity is of high importance in many scientific domains. In 2014, Herruzo et al. published a new method based on frequency-modulation atomic force microscopy to locally determine the elasticity of samples (Nat. Commun. 2014, 5, 3126). This method gives evidence for the linearity of the relation between the frequency shift of the cantilever first flexural mode Δf 1 and the square of the frequency shift of the second flexural mode Δf 2 2. In the present work, we showed that a similar linear relation exists when measuring in contact mode with a certain load F N and propose a new method for determining the elastic modulus of samples from this relation. The measurements were performed in non-dry air at ambient temperature on three different polymers (polystyrene, polypropylene and linear low-density polyethylene) and a self-assembled monolayer of 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) on a silicon oxide substrate perforated with circular holes prepared by polymer blend lithography. For all samples the relation was evidenced by recording Δf 1, Δf 2 and F N as a function of the Z-displacement curves of the piezoelectric scanner. The occurence of a plastic deformation followed by an elastic deformation is shown and explained. The necessary load F N for measuring in the elastic domain was assessed for each sample, used for mapping the frequency shifts Δf 1 and Δf 2 and for determining the elastic modulus from Δf 2 2/Δf 1. The method was used to give an estimate of the Young’s modulus of the FDTS thin film.
22
Gay, Giuliana, Marco Bovio, José Luis Minati, Albino Morando, Vittorino Novello, and Roberto Ambrosoli. "Soil management in relation to training system in a steep vineyard." OENO One 38, no. 1 (March 31, 2004): 71. http://dx.doi.org/10.20870/oeno-one.2004.38.1.935.
Full textAbstract:
<p style="text-align: justify;">In the North-West Italy, close spaced and low trunk vines are vertically trellised and Guyot pruned. In these conditions the permanent grass cover may compete with grapevine leaves and clusters for air and light, and with grapevine roots for water and nitrogen. In a « White Muscat » vineyard, grafted onto « 420A », the following soil management techniques were compared: a) permanent grass cover controlled by mowing; b) permanent grass cover controlled by foliar herbicides; c) no tillage using residual + foliar herbicides. The maximum soil cover was found on the grass cutting treatment. A good but reduced cover was obtained by the foliar herbicide used alone, stimulating the vine vigor, and giving more yields with higher total soluble solids concentration. The soil nitrifying microflora was less reduced by glufosinate-ammonium than by glyphosate. The grass cover was minimum using residual herbicides; as a consequence the erosion risk was enhanced, the soil total N and organic matter were reduced, yield and gray mold damages were increased.</p>
23
Sun, Gavin, Glen Hazlewood, Sasha Bernatsky, Gilaad G. Kaplan, Bertus Eksteen, and Cheryl Barnabe. "Association between Air Pollution and the Development of Rheumatic Disease: A Systematic Review." International Journal of Rheumatology 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/5356307.
Full textAbstract:
Objective. Environmental risk factors, such as air pollution, have been studied in relation to the risk of development of rheumatic diseases. We performed a systematic literature review to summarize the existing knowledge.Methods. MEDLINE (1946 to September 2016) and EMBASE (1980 to 2016, week 37) databases were searched using MeSH terms and keywords to identify cohort, case-control, and case cross-over studies reporting risk estimates for the development of select rheumatic diseases in relation to exposure of measured air pollutants (n=8). We extracted information on the population sample and study period, method of case and exposure determination, and the estimate of association.Results. There was no consistent evidence of an increased risk for the development of rheumatoid arthritis (RA) with exposure to NO2, SO2, PM2.5, or PM10. Case-control studies in systemic autoimmune rheumatic diseases (SARDs) indicated higher odds of diagnosis with increasing PM2.5exposure, as well as an increased relative risk for juvenile idiopathic arthritis (JIA) in American children <5.5 years of age. There was no association with SARDs and NO2exposure.Conclusion. There is evidence for a possible association between air pollutant exposures and the development of SARDs and JIA, but relationships with other rheumatic diseases are less clear.
24
Isopp, Hubert, Marco Frehner, José P. F. Almeida, Herbert Blum, Markus Daepp, Ueli A. Hartwig, Andreas Lüscher, Daniel Suter, and Josef Nösberger. "Nitrogen plays a major role in leaves when source-sink relations change: C and N metabolism in Lolium perenne growing under free air CO2 enrichment." Functional Plant Biology 27, no. 9 (2000): 851. http://dx.doi.org/10.1071/pp99151.
Full textAbstract:
This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999 Swards of Lolium perenne L. were grown in the field in a long-term free air CO2 enrichment (FACE) facility. The CO2 treatment was combined with two levels of N fertilization and regular defoliation, which resulted in plants with a wide range of source–sink relations. C and N metabolism were investigated to assess the role of carbohydrate and nitrogenous compounds in leaves in indicating source–sink relations. Sucrose exhibited the largest changes in contents during the day–night cycle; therefore, it was identified as the main short-term storage compound for night-time export. Fructan accumulation indicated the degree of surplus C supply in the source compared to C use in sinks. Nitrate content depended mainly on N fertilization, and was reduced under elevated pCO2. Nitrate appeared to indicate a current surplus of available N relative to the need for growth. Amino acid content responded strongly to N fertilization but decreased only slightly under elevated pCO2. Protein content, however, decreased significantly under elevated pCO2. The patterns of diurnal changes of C or N compounds did not differ between CO2 treatments. Down-regulation of photosynthesis appeared to occur when plants were extremely N-limited as under elevated pCO2, low N and at a late regrowth stage.
25
Jansen, Joachim, Brett F. Thornton, Alicia Cortés, Jo Snöälv, Martin Wik, Sally MacIntyre, and Patrick M. Crill. "Drivers of diffusive CH<sub>4</sub> emissions from shallow subarctic lakes on daily to multi-year timescales." Biogeosciences 17, no. 7 (April 8, 2020): 1911–32. http://dx.doi.org/10.5194/bg-17-1911-2020.
Full textAbstract:
Abstract. Lakes and reservoirs contribute to regional carbon budgets via significant emissions of climate forcing trace gases. Here, for improved modelling, we use 8 years of floating chamber measurements from three small, shallow subarctic lakes (2010–2017, n=1306) to separate the contribution of physical and biogeochemical processes to the turbulence-driven, diffusion-limited flux of methane (CH4) on daily to multi-year timescales. Correlative data include surface water concentration measurements (2009–2017, n=606), total water column storage (2010–2017, n=237), and in situ meteorological observations. We used the last to compute near-surface turbulence based on similarity scaling and then applied the surface renewal model to compute gas transfer velocities. Chamber fluxes averaged 6.9±0.3 mg CH4 m−2 d−1 and gas transfer velocities (k600) averaged 4.0±0.1 cm h−1. Chamber-derived gas transfer velocities tracked the power-law wind speed relation of the model. Coefficients for the model and dissipation rates depended on shear production of turbulence, atmospheric stability, and exposure to wind. Fluxes increased with wind speed until daily average values exceeded 6.5 m s−1, at which point emissions were suppressed due to rapid water column degassing reducing the water–air concentration gradient. Arrhenius-type temperature functions of the CH4 flux (Ea′=0.90±0.14 eV) were robust (R2≥0.93, p<0.01) and also applied to the surface CH4 concentration (Ea′=0.88±0.09 eV). These results imply that emissions were strongly coupled to production and supply to the water column. Spectral analysis indicated that on timescales shorter than a month, emissions were driven by wind shear whereas on longer timescales variations in water temperature governed the flux. Long-term monitoring efforts are essential to identify distinct functional relations that govern flux variability on timescales of weather and climate change.
26
Dobeic, M., E. Kenda, J. Mičunovič, and I. Zdovc. "Airborne Listeria spp. in the red meat processing industry." Czech Journal of Food Sciences 29, No. 4 (August 10, 2011): 441–47. http://dx.doi.org/10.17221/88/2010-cjfs.
Full textAbstract:
The aim of this study was to determine the potential presence of the airborne Listeria spp. and its correlation with the aerobic mesophilic bacteria and Listeria carcass contamination in three red meat slaughtering and three processing plants. Airborne L. seeligeri and L. innocua were determined using 8 (5.06%, n = 158) air samples taken on the locations characteristic for aerosol generating and in a chilly environment. The positive airborne samples of Listeria spp. were in an insignificant (P > 0.05) relation with the highest airborne bacteria counts. On the carcass, only 1 positive case (0.69%, n = 144) of L. innocua was determined, presumably owing to the low airborne Listeria counts and its unpredictable settling rates. In addition, insignificant (P > 0.05) influences of air moisture and airflow on the airborne Listeria were found. Nevertheles, the methods currently used to determine the airborne Listeria and its relationships to aerosol viable mesophilic bacteria and carcass contamination need to be reconsidered in future investigations.
27
Colilla, Susan, Nancy J. Cox, and David A. Ehrmann. "Heritability of Insulin Secretion and Insulin Action in Women with Polycystic Ovary Syndrome and Their First Degree Relatives1." Journal of Clinical Endocrinology & Metabolism 86, no. 5 (May 1, 2001): 2027–31. http://dx.doi.org/10.1210/jcem.86.5.7518.
Full textAbstract:
Polycystic ovary syndrome (PCOS), one of the most common endocrine disorders of reproductive age women, is associated with an increased risk of type 2 diabetes mellitus. Defects in both insulin action and insulin secretion contribute to this predisposition to diabetes, but the extent to which these defects are heritable among PCOS families has not been examined. In the present study we used the frequently sampled iv glucose tolerance test to quantitate insulin secretion (AIRg), insulin action (Si), and their product (AIRg × Si) among women with PCOS (n= 33) and their nondiabetic first degree relatives (n = 48). We then quantitated the heritability of these measures from familial correlations estimated within a genetic model. Familial (spousal, ρMF; parent-offspring, ρPO; and sibling, ρSS) correlations were derived for log-transformed body mass index (BMI) as well as for AIRg, Si, and AIRg × Si, the latter three of which were adjusted for BMI. There was no evidence of significant heritability for either lnBMI or lnSi in these families. In contrast, the sibling correlation (ρSS = 0.74) for lnAIRg was highly significant (χ2 = 7.65; 1 df; P= 0.006). In addition, the parameter quantitating insulin secretion in relation to insulin sensitivity [i.e. ln(AIRg × Si)] was significant among siblings (ρSS = 0.74;χ 2 = 4.32; 1 df; P = 0.04). In summary, the results of the present study indicate that there is an heritable component to β-cell dysfunction in families of women with PCOS. We conclude that heritability of β-cell dysfunction is likely to be a significant factor in the predisposition to diabetes in PCOS.
28
Jerin, Sahajadi, Md Ataul Gani, Md Almujaddade Al Fasane, and Moniruzzaman Khondker. "Dynamics Of Environmental Factors In Relation To Phytoplankton Species In A Pond Of Old Dhaka, Bangladesh." Journal of the Asiatic Society of Bangladesh, Science 42, no. 2 (December 25, 2016): 169–75. http://dx.doi.org/10.3329/jasbs.v42i2.46220.
Full textAbstract:
The relationship between different environmental factors and abundance of phytoplankton species was studied for one year in a pond of old Dhaka named Sikkatuli pond. The range of annual mean of different variables in the pond was air and water temperatures 20 - 31.75˚C, secchi depth 21 - 54 cm, pH 7.39 - 8.3, alkalinity 3.9 - 9.2 meq/l, conductivity 484.5 - 2273.34 μS/cm, DO 3.35 - 8.33 mg/l, TDS 224.67 - 380.5 mg/l, SRS 12.03 - 79.93 mg/l, NO3-N 0.18 - 0.435 mg/l, SRP 0.33 – 4.28 μg/l, chlorophyll a 196.08 - 362.76 μg/l and phaeopigment 30.51 - 212.2 μg/l. During the investigation Cryptomonas erosa var. reflexa, Rhodomonas lens, Cyclotella comensis, Merismopedia gluaca, Euglena acus, Lyngbya limnetica, Chlorella vulgaris, Arthrospira platensis, Trachelomonas volvocina, Oscillatoria agardhii, Synechocystis aquatilis, Pelonema aphane and Peridinium sp. were found to be dominant phytoplankton. Pearson correlation showed that only alkalinity correlated with phytoplankton at 5% significant level. RDA orientation showed that air temperature, water temperature, secchi depth, chl a and pheopigment concentration are the important environmental factors. RDA ordination plot also showed that phytoplankton species of Pelonema aphane and Peridinium sp. were negatively correlated with secchi depth. Negative correlation was also observed between Trachelomonas volvocina and water temperature.
Asiat. Soc. Bangladesh, Sci. 42(2): 169-175, December 2016
29
Ren, Xiaodan, Ping Li, Jianbo Li, Xiaoyi Yang, Chaohua Guo, and Quanhong Li. "Effect of Oxyethylene Groups of Fatty Alcohol Polyoxyethylene Ether Sodium Sulfates on Equilibrium and Dynamic Surface Tension in Relation to Wetting Properties." Tenside Surfactants Detergents 58, no. 5 (September 1, 2021): 394–400. http://dx.doi.org/10.1515/tsd-2020-2343.
Full textAbstract:
Abstract The effect of hydrophilic chain of surfactants fatty alcohol polyoxyethylene ether sodium sulphates (AEnS, n = 2, 3, 7) on surface properties and wetting properties was investigated by the measurement of equilibrium surface tension, dynamic surface tension and dynamic contact angle. The fatty alcohol polyoxyethylene ether sodium sulphates with different head group sizes were used. From the results of equilibrium surface tension measurements, we could obtain the critical micellisation concentration, adsorption efficiency, maximum surface excess concentration and Langmuir equilibrium adsorption constant at air/liquid interface. The dynamic surface tension results showed that the adsorption of aqueous solutions at the air/liquid interface follows a mixed-diffusion kinetic adsorption mechanism. In conclusion, for both studied surfactant, the longer the oxyethylene chains, the higher the maximum rate of surface tension reduction, the higher the diffusivity and wetting properties in terms of contact angle.
30
Hertel, O., C. A. Skjøth, S. Reis, A. Bleeker, R. Harrison, J. N. Cape, D. Fowler, et al. "Governing processes for reactive nitrogen compounds in the atmosphere in relation to ecosystem, climatic and human health impacts." Biogeosciences Discussions 9, no. 7 (July 27, 2012): 9349–423. http://dx.doi.org/10.5194/bgd-9-9349-2012.
Full textAbstract:
Abstract. Reactive nitrogen (Nr) compounds have different fates in the atmosphere due to differences in governing processes of physical transport, deposition and chemical transformation. Nr compounds addressed here include reduced nitrogen (NHx: ammonia (NH3) and its reaction product ammonium (NH4+)), oxidized nitrogen (NOy: nitrogen monoxide (NO) + nitrogen dioxide (NO2) and their reaction products) as well as organic nitrogen compounds (organic N). Pollution abatement strategies need to take into account these differences in the governing processes of these compounds when assessing their impact on ecosystem services, biodiversity, human health and climate. NOx (NO + NO2) emitted from traffic affects human health in urban areas where the presence of buildings increases the residence time in streets. In urban areas this leads to enhanced exposure of the population to NOx concentrations. NOx emissions have little impact on nearby ecosystems because of the small dry deposition rates of NOx. These compounds need to be converted into nitric acid (HNO3) before removal through deposition is efficient. HNO3 sticks quickly to any surface and is thereby either dry deposited or incorporated into aerosols as nitrate (NO3−). In contrast to NOx compounds, NH3 has potentially high impacts on ecosystems near the main agricultural sources of NH3 because of its large ground-level concentrations along with large dry deposition rates. Aerosol phase NH4+ and NO3− contribute significantly to background PM2.5 and PM10 (mass of aerosols with a diameter of less than 2.5 and 10 μm, respectively) with an impact on radiation balance as well as potentially on human health. Little is known quantitatively and qualitatively about organic N in the atmosphere, other than that it contributes a significant fraction of wet-deposited N, and is present in both gaseous and particulate forms in the atmosphere. Further studies are needed to characterize the sources, air chemistry and removal rates of organic N emissions.
31
Firman, D. M., P. J. O'Brien, and E. J. Allen. "Appearance and growth of individual leaves in the canopies of several potato cultivars." Journal of Agricultural Science 125, no. 3 (December 1995): 379–94. http://dx.doi.org/10.1017/s0021859600084884.
Full textAbstract:
SUMMARYLeaf appearance of contrasting potato cultivars was examined in field experiments at Cambridge, UK, between 1985 and 1990. Three experiments examined the effects of N fertilizer on the appearance and growth of leaves. Four experiments examined leaf appearance over a wide range of planting dates and in two of these experiments different physiological ages of seed were compared.Linear regression of rate of appearance of main-stem leaves on air temperature indicated a strong dependence of rate of leaf appearance on temperature in the cultivar Maris Piper with a phyllochron of c. 31 K d/leaf but in Estima variation in rate of leaf appearance was only partly explained by differences in air temperature. The phyllochron of main-stem leaves in Estima and Home Guard was shorter for old seed than young seed but there was little effect of seed age in four other cultivars. The phyllochron of main-stem leaves was longer without N fertilizer than with N but the difference in the phyllochron between rates of applied N was small. Leaf appearance on sympodial branches was slower and more variable than on the main-stem. Growth of branches differed between cultivars, particularly with no N fertilizer. In the determinate cultivars Estima and Diana there was restricted growth of branches but in the indeterminate cultivar Cara, significant leaf area was contributed by branches. The duration of leaf appearance and longevity of individual leaves is discussed in relation to N, temperature and cultivar.
32
Camargo-Bortolin, Lívia H. G. de, Carlos H. B. A. Prado, Gustavo M. Souza, and Paula Novaes. "Autonomy and network modulation of photosynthesis and water relations of Coffea arabica in the field." Brazilian Journal of Plant Physiology 20, no. 2 (June 2008): 141–51. http://dx.doi.org/10.1590/s1677-04202008000200006.
Full textAbstract:
The degree of connection between leaf gas exchange and leaf water potential, and the autonomy of these variables in relation to meteorological conditions were determined in three cultivars of Coffea arabica during clear and cloudy days. High values of vapor pressure deficit, air temperature and photosynthetic photon flux density resulted in low leaf autonomy during a clear day, irrespective the degree of connection among leaf physiological variables. Tight synchronization between physiological and meteorological variables was considered one important cause of net photosynthesis (P N) decreasing during a clear day. In contrast, diurnal P N was around three times higher on a cloudy day, when all cultivars presented high autonomy. Principal component analyses corroborated autonomy results revealing unambiguous opposition between leaf physiological and meteorological vectors, besides less leaf physiological variability throughout the clear day. Despite these general responses during clear and cloudy days, there were significant differences among studied cultivars. Leaf autonomy was an important reference to evaluate C. arabica under environmental stress and should be taken into account when selecting cultivars under field conditions.
33
Aida, Sumihisa, Kiichiro Taga, Tomohiro Yamakura, Hiroshi Endoh, and Koki Shimoji. "Headache after Attempted Epidural Block." Anesthesiology 88, no. 1 (January 1, 1998): 76–81. http://dx.doi.org/10.1097/00000542-199801000-00014.
Full textAbstract:
Background Postmeningeal puncture headache (PMPH) is typically attributed to the loss of cerebrospinal fluid (CSF). However, when it occurs after an attempted epidural puncture, it may be due to either CSF loss or, potentially, to the subarachnoid injection of air used as a part of "loss-of-resistance" testing. This study was performed to examine the relation between intrathecal air and PMPH. Methods Using a loss-of-resistance test with an air-filled (n = 1,812; air group) or saline-filled (n = 1,918; saline group) syringe, epidural block was performed in patients with acute or chronic pain. The dura was judged to be perforated not only when backflow of CSF was recognized in the needle but also when signs and symptoms solely attributable to meningeal perforation were seen, such as high spinal blockade or severe motor blockade. The incidence, onset time, and duration of PMPH in the air and saline groups were compared. In all patients with signs of meningeal perforation, brain computed tomography was examined. Results The incidence of PMPH in the air group (32 cases) was significantly higher than that in the saline group (5 cases), although the occurrences of meningeal perforation between the air (48 cases) and saline (51 cases) groups did not differ significantly. Intrathecal air bubbles were detected on brain computed tomography in both the deep supraspinal structures such as the ventricles, Silvian fissures and cisterns, and the superficial subarachnoid space in 30 of 32 patients with PMPH in the air group, whereas no intrathecal air bubbles were seen in the saline group. PMPH was significantly more rapid in onset and shorter in duration in the air group than that in the saline group. Conclusions The use of air for loss-of-resistance testing during epidural block was associated with a higher incidence of PMPH, which might be attributable to subarachnoid air injection and CSF leakage.
34
Et al., Al Kinani. "Effect of Refractive Index on Photon Natural Mass and Wavelength." Baghdad Science Journal 16, no. 4(Suppl.) (December 18, 2019): 1017. http://dx.doi.org/10.21123/bsj.2019.16.4(suppl.).1017.
Full textAbstract:
In this article it is proved experimentally that the photon is a particle that has mass and constant wavelength by explaining the effect of refractive index on the wavelength and the natural mass of photon. It is very difficult to measure the mass of photon, a simple and easy process was proposed in this paper to calculate the mass length of photon in vacuum (Y) and in medium (Y*), by measuring the length of laser beam in air (Lair) and in medium (Lmed). A new method was postulated to calculate refractive index by using these relations (n = Y*/Y), and (n = Lmed / Lair) which supposed a new theory of light.
35
Shawnim, Paybar Ali, and Fouad Mohammad. "COMPRESSIVE STRENGTH OF FOAMED CONCRETE IN RELATION TO POROSITY USING SEM IMAGES." Journal of Civil Engineering, Science and Technology 10, no. 1 (April 25, 2019): 34–44. http://dx.doi.org/10.33736/jcest.1005.2019.
Full textAbstract:
Foamed concrete specimens were examined for compressive strength at (28 and 180) days air sealed curing, as well as at 28 days water cured. Also, the microstructure of fifteen selected FC specimens was investigated for porosity in relation to compressive strength using Scanning Electron Microscopy (SEM) images. Twenty two batches of FC specimens of the densities (1100, 1600 and 1800) kg/m3 were made with fine sand and brick aggregates with toner and metakaolin (MK) inclusion as additives, they were casted in polystyrene cube moulds of (100x100x100) mm. Results show, it is possible to produce FC with high compressive strength in the range of (28.5 to 59.2) N/mm2, with a variety of materials, while the 1600 kg/m3 density with the inclusion of toner and MK20 is the favourite, which can be used for structural elements. Conventionally, compressive strength is in an inverse relationship with porosity, as porosity increases, compressive strength decreases, but using toner and MK20 can alter this relationship between porosity and compressive strength, where by it is possible to produce a relatively light weight high porosity FC matrix to exhibit high compressive strength. Maturity of the FC at 180 days, can demonstrate an increase in the compressive strength. The microstructural investigations through SEM images revealed, the FC mix made with sand or brick only, exhibits an irregular shape factor of the micro pore system with the pore size in the range of (10 to 70) µm, while those made with the inclusion of toner and MK20 have a regular shape factor of a matrix of finer micro pore system of the sizes in the range of (0.01 to 10.0) µm, all of which are evenly distributed, and have a big influence on the properties of the FC, particularly, on compressive strength. Contrary to the conventional method of air sealed curing for FC, water curing method can equally give the same or a slightly better result in respect of compressive strength for some particular densities.
36
Kirillova, E. N., A. Andersson, J. Han, M. Lee, and Ö. Gustafsson. "Sources and light absorption of water-soluble brown carbon aerosols in the outflow from northern China." Atmospheric Chemistry and Physics Discussions 13, no. 7 (July 25, 2013): 19625–48. http://dx.doi.org/10.5194/acpd-13-19625-2013.
Full textAbstract:
Abstract. High loadings of anthropogenic carbonaceous aerosols in Chinese air influence the air quality for over 1 billion people and impact the regional climate. A large fraction (17–80%) of this aerosol carbon is water soluble, promoting cloud formation and thus climate cooling. Recent findings, however, suggest that water-soluble carbonaceous aerosols also absorb sunlight, bringing additional direct and indirect climate warming effects, yet the extent and nature of light absorption by this water-soluble brown carbon (WS-BrC) and its relation to sources is poorly understood. Here, we combine source estimates constrained by dual-carbon-isotope with light absorption measurements of WS-BrC for a March 2011 campaign at the Korea Climate Observatory at Gosan (KCOG), a receptor station in SE Yellow Sea for the outflow from N. China. The mass absorption cross-section (MAC) of WS-BrC for air masses from N. China were in general higher (0.8–1.1 m2 g−1), than from other source regions (0.3–0.8 m2 g−1). We estimate that this effect corresponds to 13–49% of the radiative forcing caused by light absorption by black carbon. Radiocarbon constraints show that the WS-BrC in Chinese outflow had significantly higher amounts of fossil sources (30–50%) compared to previous findings in S. Asia, N. America and Europe. Stable carbon (δ13C) measurements indicated influence of aging during air mass transport. These results indicate the importance of incorporating WS-BrC in climate models and the need to constrain climate effects by emission source sector.
37
Barij, Nadia, Jan Čermák, and Alexia Stokes. "Azimuthal variations in xylem structure and water relations in cork oak (Quercus suber)." IAWA Journal 32, no. 1 (2011): 25–40. http://dx.doi.org/10.1163/22941932-90000040.
Full textAbstract:
Azimuthal variations in xylem conductivity and transpiration can occur in trees and may be due to heterogeneity in environmental factors. In cork oak (Quercus suber L.), it can be hypothesized that such modifications may be more pronounced because the insulating layer of bark is harvested every 9–10 years, thus cambial cells will be exposed to fluctuations in the microenvironment. To investigate whether xylem structure and water relations differed around the stems of mature cork oak, sap flow per section and xylem structure were measured on the northern (N) and southern (S) sides of nine trees during three months in Portugal, using the Trunk Sector Heat Balance method. Crown size was measured on both sides of each tree and increment wood cores were extracted from the sites where sap flow was measured in five trees. Wood moisture content, earlywood (EW) vessel size and density were measured and theoretical hydraulic conductivity for individual vessels (Lth) was calculated along the N and S stem radial profiles. No significant differences in crown size between the two sides of the tree were found, but sap flow was higher on the S side of the tree in May only. No differences in wood moisture content were observed along the length of each wood core throughout the heartwood. Significant differences in vessel size occurred, with a greater diameter and surface area on the N side of the tree, and consequently Lth was significantly greater. These conduit diameters on the S facing side of the tree may be smaller in response to a combination of signals and trade-offs due to the heterogeneous air and soil environment around the tree.
38
Finell, Eerika, Asko Tolvanen, Juha Pekkanen, Jaana Minkkinen, Timo Ståhl, and Arja Rimpelä. "Psychosocial Problems, Indoor Air-Related Symptoms, and Perceived Indoor Air Quality among Students in Schools without Indoor Air Problems: A Longitudinal Study." International Journal of Environmental Research and Public Health 15, no. 7 (July 16, 2018): 1497. http://dx.doi.org/10.3390/ijerph15071497.
Full textAbstract:
The effect of students’ psychosocial problems on their reporting of indoor air quality (subjective IAQ) and indoor air-related (IA-related) symptoms has not been studied in schools in a longitudinal setting. Therefore, we analyzed whether changes in students’ psychosocial problems (socioemotional difficulties and perceived teacher–student relations) between the beginning of seventh grade (age 12–13 years) and the end of ninth grade (15–16 years) predicted subjective IAQ and IA-related symptoms at the end of ninth grade. In order to explore the independent effect of psychosocial factors, we focused only on students in schools without observed indoor air problems. The analysis was of longitudinal data (N = 986 students) using latent change modelling. Increased socioemotional difficulties were related to more IA-related symptoms (standardized beta = 0.20) and deteriorated subjective IAQ (standardized beta = 0.20). Increased problems in teacher–student relations were related to deteriorated subjective IAQ (standardized beta = 0.21). Although students’ psychosocial problems explained only 9–13% of the total variances, our findings support the notion that psychosocial factors also need to be taken into account in the evaluation of IAQ and the prevalence of IA-related symptoms in schools.
39
Byčenkienė, Steigvilė, Vadimas Dudoitis, and Vidmantas Ulevicius. "The Use of Trajectory Cluster Analysis to Evaluate the Long-Range Transport of Black Carbon Aerosol in the South-Eastern Baltic Region." Advances in Meteorology 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/137694.
Full textAbstract:
Trajectory cluster analysis and source-receptor models (the potential source contribution function (PSCF), concentration weighted trajectories (CWT), and trajectory source apportionment (TSA)) were applied to investigate the source-receptor relationship for the aerosol black carbon (BC) measured at the coastal site (Preila, 55.55°N, 21.04°E) during 2013. The main sources and paths of advection to the south-eastern Baltic region and its relation to black carbon concentration were identified. The 72 h backward trajectories of air masses arriving at Preila from January to December 2013 were determined and were categorized by clustering them into six clusters. Subsequently, BC levels at Preila associated with each air mass cluster during this period were analyzed. The PSCF and CWT analysis shows that, on high BC concentration days, the air masses commonly originated and passed over southern regions of Europe before arriving at Preila in winter, while a strong impact of wildfires was observed in spring.
40
Boettcher, Philipp A., Shyam K. Menon, Brian L. Ventura, Guillaume Blanquart, and Joseph E. Shepherd. "Cyclic flame propagation in premixed combustion." Journal of Fluid Mechanics 735 (October 23, 2013): 176–202. http://dx.doi.org/10.1017/jfm.2013.495.
Full textAbstract:
AbstractIn experiments of hot surface ignition and subsequent flame propagation, a puffing flame instability is observed in mixtures that are stagnant and premixed prior to ignition. By varying the size of the hot surface, power input, and combustion vessel volume, it was determined that the instability is a function of the interaction of the flame, with the fluid flow induced by the combustion products rather than the initial plume established by the hot surface. Pressure ranges from 25 to 100 kPa and mixtures of n-hexane/air with equivalence ratios between $\phi = 0. 58$ and 3.0 at room temperature were investigated. Equivalence ratios between $\phi = 2. 15$ and 2.5 exhibited multiple flame and equivalence ratios above $\phi = 2. 5$ resulted in puffing flames at atmospheric pressure. The phenomenon is accurately reproduced in numerical simulations and a detailed flow field analysis revealed competition between the inflow velocity at the base of the flame and the flame propagation speed. The increasing inflow velocity, which exceeds the flame propagation speed, is ultimately responsible for creating a puff. The puff is then accelerated upward, allowing for the creation of the subsequent instabilities. The frequency of the puff is proportional to the gravitational acceleration and inversely proportional to the flame speed. A scaling relationship describes the dependence of the frequency on gravitational acceleration, hot surface diameter, and flame speed. This relation shows good agreement for rich n-hexane/air and lean hydrogen/air flames, as well as lean hexane/hydrogen/air mixtures.
41
Kirillova, E. N., A. Andersson, J. Han, M. Lee, and Ö. Gustafsson. "Sources and light absorption of water-soluble organic carbon aerosols in the outflow from northern China." Atmospheric Chemistry and Physics 14, no. 3 (February 7, 2014): 1413–22. http://dx.doi.org/10.5194/acp-14-1413-2014.
Full textAbstract:
Abstract. High loadings of anthropogenic carbonaceous aerosols in Chinese air influence the air quality for over one billion people and impact the regional climate. A large fraction (17–80%) of this aerosol carbon is water-soluble, promoting cloud formation and thus climate cooling. Recent findings, however, suggest that water-soluble carbonaceous aerosols also absorb sunlight, bringing additional direct and indirect climate warming effects, yet the extent and nature of light absorption by this water-soluble "brown carbon" and its relation to sources is poorly understood. Here, we combine source estimates constrained by dual carbon isotopes with light-absorption measurements of water-soluble organic carbon (WSOC) for a March 2011 campaign at the Korea Climate Observatory at Gosan (KCOG), a receptor station in SE Yellow Sea for the outflow from northern China. The mass absorption cross section at 365 nm (MAC365) of WSOC for air masses from N. China were in general higher (0.8–1.1 m2 g−1), than from other source regions (0.3–0.8 m2 g−1). However, this effect corresponds to only 2–10% of the radiative forcing caused by light absorption by elemental carbon. Radiocarbon constraints show that the WSOC in Chinese outflow had significantly higher fraction fossil sources (30–50%) compared to previous findings in S. Asia, N. America and Europe. Stable carbon (δ13C) measurements were consistent with aging during long-range air mass transport for this large fraction of carbonaceous aerosols.
42
Knies, Maximilian, Mai Lê Anh, Ulrich Keßler, and Michael Ruck. "Crystal structures of the tetrachloridoaluminates(III) of rubidium(I), silver(I), and lead(II)." Zeitschrift für Naturforschung B 75, no. 1-2 (February 25, 2020): 117–23. http://dx.doi.org/10.1515/znb-2019-0162.
Full textAbstract:
AbstractThe reactions of the binary metal chlorides AgCl, RbCl and PbCl2 at T = 180°C in the ionic liquid [BMIm]Cl · 4AlCl3 (BMIm = 1-n-butyl-3-methylimidazolium) yielded air-sensitive, colorless, high-quality crystals of their tetrachloridoaluminate(III) salts. Thereby, the obstructions that hinder proper crystallization of these compounds from pristine AlCl3 melts were circumvented. X-ray diffraction on single-crystals revealed a monoclinic structure (space group P21/c) for Ag[AlCl4], which unexpectedly has a closer relation to Cu[AlCl4]2 than to Cu[AlCl4]. Rb[AlCl4] crystallizes in the baryte structure type (orthorhombic, Pnma), and Pb[AlCl4]2 is isotypic to α-Sr[GaCl4]2 (orthorhombic, Pbca).
43
Maheu, Maxime, Ahlem Elblidi, and Issam Saliba. "Investigating Performance of cVEMP and oVEMP in the Identification of Superior Canal Dehiscence in Relation to Dehiscence Location and Size." Audiology Research 11, no. 3 (September 9, 2021): 452–62. http://dx.doi.org/10.3390/audiolres11030042.
Full textAbstract:
Compare the sensitivity and specificity of cVEMP (500 Hz), oVEMP (500 Hz and 4 kHz) in the identification of SSCD. A secondary objective was to identify the influence of dehiscence size and location on cVEMP and oVEMP responses. Methods: Individuals with unilateral (n = 16) and bilateral (n = 10) scan confirmed SSCD were assessed using air-conducted cVEMP and oVEMP Results: For cVEMP, an amplitude cutoff of 286.9 μV or a threshold cutoff of 67.5 dBnHL revealed, respectively, a sensitivity of 75% and 70.6% and a specificity of 69.4% and 100%. For oVEMP (500 Hz), an amplitude cutoff of 10.8 μV or a threshold cutoff of 77.5 dBnHL revealed a sensitivity of 83.33% and a specificity of 87.5% and 80%, respectively. oVEMP (4 kHz), an amplitude cutoff of 3.1 μV, revealed a high specificity of 100% but a low sensitivity of 47.2%. A positive correlation was noted between the length of the SSCD and the cVEMP and oVEMP (500 Hz) thresholds and cVEMP amplitude. Conclusions: Our results support the use of oVEMP in the identification of SSCD. The presence of oVEMP (500 Hz) with an amplitude higher or equal to 10.8 μV, a threshold lower or equal to 77.5 dBnHL or oVEMP (4 kHz) amplitude of 3.1 μV represents the most useful to identify SSCD.
44
Heinzinger, Catherine, Lu Wang, James Bena, Lynn Bekris, Nancy Foldvary-Schaefer, Jagan Pillai, Sujata Rao, Stephen Rao, James Leverenz, and Reena Mehra. "421 Elucidating Circadian and Sleep Phenotypes and Relation to Cognitive Impairment in Alzheimer’s Dementia." Sleep 44, Supplement_2 (May 1, 2021): A166—A167. http://dx.doi.org/10.1093/sleep/zsab072.420.
Full textAbstract:
Abstract Introduction Although sleep disruption in Alzheimer’s disease (AD) pathogenesis has been described, the role of circadian rhythm dysfunction (CRD) is less understood. We hypothesize greater CRD and sleep disruption with poorer cognitive function in AD compared to normal cognition. Methods We examined 3 groups:1)mild cognitive impairment with positive AD biomarkers(MCI-AD),n=18, 2)cognitively normal at high risk for AD(HR)(APOEƐ4 carriers),n=19, 3)cognitively normal APOEƐ4 non-carriers(CL),n=16 (National Institute of Aging, IMMUNE-AD). DNA extraction and APOEƐ4 genotyping were performed under the Cleveland Clinic Lou Ruvo Center for Brain Health Aging and Neurodegenerative Disease Biobank. We evaluated actigraphy-based (Motionlogger MicroWatch, Ambulatory Monitoring,Inc®) sleep (wake episodes(WE), total sleep time(TST), sleep efficiency(SE), sleep fragmentation index(SFI)) and circadian (mesor, amplitude, robustness, sleep regulatory index(SRI), intradaily stability) predictors and sleep study-based (ApneaLink Air by ResMed®) predictors (apnea hypopnea index(AHI,3% desaturation) and recording time<90%SaO2) across the groups and assessed association with cognition (Mini-Mental State Exam(MMSE)). Analysis of variance (ANOVA) or Kruskal-Wallis with Bonferroni adjustment was used for cross-group comparisons. ANCOVA assessed cross-group association of MMSE and sleep/circadian indices. Models were adjusted for age, sex, race, education, and BMI. Results Age differed across MCI-AD, HR, and CL groups (68.4±6.2,71.2±3.7,73.7±3.7 respectively,p=0.008). MCI-AD had more WE than HR and CL (14.4±5.6,10.9±3.9,10.9±3.5 respectively,p=0.033). In MCI-AD, the following associations were observed: 5% increase in SE was associated with 0.49 point higher MMSE (coefficient0.49, 95%CI[0.03,0.95],p=0.038), 1 hour increase in TST was associated with 0.81 point higher MMSE (coefficient0.81, 95%CI[0.24,1.37],p=0.006), and 1 unit increase in SFI was associated with 0.36 point lower MMSE (coefficient-0.36, 95%CI[-0.64,-0.08],p=0.013). Key measures differed: CLs had lower AHI, MCI-AD had less TST SaO2<90%, MCI-AD had the largest and HR the lowest SFI, and MCI-AD had lesser robustness but higher mesor and amplitude. Conclusion In this comparative study of carefully AD biomarker-phenotyped and APOEƐ4-genotyped patients and normal cognition controls, less sleep time and more fragmented sleep are associated with poorer MMSE scores in MCI-AD. Preliminary results show cognitively normal participants at risk of AD(HR) do not show CRD seen in MCI-AD and are more consistent with controls (CL). Support (if any) Catalyst Award. MCI cohort: Alzheimer’s Association, 2014-NIRG-305310. IMMUNE-AD, R01AG022304. CADRC, P30 AG062428. Jane and Lee Seidman Fund.
45
Burrows, Rhoda L., and Frank J. Peryea. "Soil Acidification Potential of Four Commercial Nitrogen Solutions Used for Fertigation." HortScience 30, no. 4 (July 1995): 879D—879. http://dx.doi.org/10.21273/hortsci.30.4.879d.
Full textAbstract:
Nitrification-induced subsoil acidification is a major problem encountered with the use of ammonium- or urea-containing fertilizer solutions for drip fertigation of tree fruit crops. We conducted a laboratory experiment to evaluate the soil acidification potential of the four fertilizer N solutions most frequently used for fertigation within the Washington tree fruit industry. Treatments were five orchard soils x four commercial N solutions (calcium nitrate, calcium-ammonium nitrate, ammonium nitrate, urea-ammoniun nitrate) x four N rates (0, 100, 200, 500 mg N/kg). Air-dry subsamples of each soil were inoculated with fresh soil known to exhibit nitrifying behavior amended with treatment solutions. Subsamples were maintained at simulated field capacity of –15 kPa. Soil pH was measured after 5 weeks incubation. The treatment solutions were reapplied and pH measured after another 5 weeks. The soil were then leached with distilled water and further incubated to determine if pH would increase as has been observed in the field. The fertilizer solutions acidified the soils in direct relation to their ammonium plus urea content. The calcium nitrate solution was acidifying because it contains ammonium nitrate as an impurity. We will present the pH “rebound” data.
46
Zinck, T., R. Illum, and I. Jansen-Olesen. "Increased Expression of Endothelial and Neuronal Nitric Oxide Synthase In Dura and Pia Mater After Air Stress." Cephalalgia 26, no. 1 (January 2006): 14–25. http://dx.doi.org/10.1111/j.1468-2982.2005.00978.x.
Full textAbstract:
Stress is the leading precipitating factor for migraine attacks but the underlying mechanism is currently unknown. Nitric oxide (NO) has been implicated in migraine pathogenesis based on the ability of NO donors to induce migraine attacks. In the present study, we investigated in Wistar rats the effect of air stress on nitric oxide synthase (NOS) mRNA and protein expression in dura and pia mater using real-time polymerase chain reaction and Western blotting, respectively. Endothelial (e)NOS protein expression was significantly increased in dura and pia mater after air stress. Significantly augmented neuronal (n)NOS protein expression was detected in pia mater after air stress but not in dura mater. Inducible NOS mRNA and protein expression levels in dura and pia mater were unaffected by stress. The increased expression of eNOS in dura mater and eNOS and nNOS in pia mater seen after stress could not be antagonized by treatment with the migraine drug sumatriptan. These findings point towards the involvement of increased NO concentrations in dura and pia mater in response to air stress. However, the role of these findings in relation to migraine pathophysiology remains unclear.
47
Milovanovic, Bosko, Milan Radovanovic, and Tamara Jojic-Glavonjic. "Linkage between water temperature of the subtropical Atlantic, the Azores maximum and air temperature in Serbia." Glasnik Srpskog geografskog drustva 90, no. 2 (2010): 69–84. http://dx.doi.org/10.2298/gsgd1002069m.
Full textAbstract:
The paper explores the link between water temperature of the subtropical part of the Atlantic Ocean (the belt of 25 to 40? N), atmospheric pressure and air temperature in Belgrade and Serbia. The main point of the research is to examine the linkage between the Azores air pressure maximum with the changes of water temperature in the subtropical belt of the Atlantic (given in the net 5x5?). Using the hierarchical cluster analyses, 10 clusters of water temperature of the subtropical part of the Atlantic Ocean were selected. Their linkage between the position and the intensity of the Azores maximum was examined by multiple-linear regression. It was established which of the clusters influenced most the geographical latitude, geographical longitude and the intensity of the Azores maximum, as well as which of the grid cells represented the most significant predictors within each of the clusters. Examining the relation between the position and the intensity of the Azores maximum with the air temperature in Belgrade, i.e. Serbia, it was established that the linkage with the geographical latitude of this action centre was the most significant. .
48
Wu, Xue, Sabine Griessbach, and Lars Hoffmann. "Equatorward dispersion of a high-latitude volcanic plume and its relation to the Asian summer monsoon: a case study of the Sarychev eruption in 2009." Atmospheric Chemistry and Physics 17, no. 21 (November 13, 2017): 13439–55. http://dx.doi.org/10.5194/acp-17-13439-2017.
Full textAbstract:
Abstract. Tropical volcanic eruptions have been widely studied for their significant contribution to stratospheric aerosol loading and global climate impacts, but the impact of high-latitude volcanic eruptions on the stratospheric aerosol layer is not clear and the pathway of transporting aerosol from high latitudes to the tropical stratosphere is not well understood. In this work, we focus on the high-latitude volcano Sarychev (48.1° N, 153.2° E), which erupted in June 2009, and the influence of the Asian summer monsoon (ASM) on the equatorward dispersion of the volcanic plume. First, the sulfur dioxide (SO2) emission time series and plume height of the Sarychev eruption are estimated with SO2 observations of the Atmospheric Infrared Sounder (AIRS) and a backward trajectory approach using the Lagrangian particle dispersion model Massive–Parallel Trajectory Calculations (MPTRAC). Then, the transport and dispersion of the plume are simulated using the derived SO2 emission time series. The transport simulations are compared with SO2 observations from AIRS and validated with aerosol observations from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). The MPTRAC simulations show that about 4 % of the sulfur emissions were transported to the tropical stratosphere within 50 days after the beginning of the eruption, and the plume dispersed towards the tropical tropopause layer (TTL) through isentropic transport above the subtropical jet. The MPTRAC simulations and MIPAS aerosol data both show that between the potential temperature levels of 360 and 400 K, the equatorward transport was primarily driven by anticyclonic Rossby wave breaking enhanced by the ASM in boreal summer. The volcanic plume was entrained along the anticyclone flows and reached the TTL as it was transported southwestwards into the deep tropics downstream of the anticyclone. Further, the ASM anticyclone influenced the pathway of aerosols by isolating an aerosol hole inside of the ASM, which was surrounded by aerosol-rich air outside. This transport barrier was best indicated using the potential vorticity gradient approach. Long-term MIPAS aerosol detections show that after entering the TTL, aerosol from the Sarychev eruption remained in the tropical stratosphere for about 10 months and ascended slowly. The ascent speed agreed well with the ascent speed of the water vapor tape recorder. Furthermore, a hypothetical MPTRAC simulation for a wintertime eruption was carried out. It is shown that under winter atmospheric circulations, the equatorward transport of the plume would be suppressed by the strong subtropical jet and weak wave breaking events. In this hypothetical scenario, a high-latitude volcanic eruption would not be able to contribute to the tropical stratospheric aerosol layer.
49
Clarke, Kayan, Andres Manrique, Tara Sabo-Attwood, and Eric S. Coker. "A Narrative Review of Occupational Air Pollution and Respiratory Health in Farmworkers." International Journal of Environmental Research and Public Health 18, no. 8 (April 13, 2021): 4097. http://dx.doi.org/10.3390/ijerph18084097.
Full textAbstract:
The agricultural crop sector in the United States depends on migrant, seasonal, and immigrant farmworkers. As an ethnic minority group in the U.S. with little access to health care and a high level of poverty, farmworkers face a combination of adverse living and workplace conditions, such as exposure to high levels of air pollution, that can place them at a higher risk for adverse health outcomes including respiratory infections. This narrative review summarizes peer-reviewed original epidemiology research articles (2000–2020) focused on respirable dust exposures in the workplace and respiratory illnesses among farmworkers. We found studies (n = 12) that assessed both air pollution and respiratory illnesses in farmworkers. Results showed that various air pollutants and respiratory illnesses have been assessed using appropriate methods (e.g., personal filter samplers and spirometry) and a consistent pattern of increased respiratory illness in relation to agricultural dust exposure. There were several gaps in the literature; most notably, no study coupled occupational air exposure and respiratory infection among migrant, seasonal and immigrant farmworkers in the United States. This review provides an important update to the literature regarding recent epidemiological findings on the links between occupational air pollution exposures and respiratory health among vulnerable farmworker populations.
50
Nurislamova, Tatyana V., Vadim B. Alekseev, Tatyana S. Ulanova, and Olga A. Maltseva. "Chromato-mass-spectrometric identification of asymmetric dimethylhydrazine and N-nitrosodimethylamine." Hygiene and sanitation 100, no. 5 (June 15, 2021): 422–27. http://dx.doi.org/10.47470/0016-9900-2021-100-5-422-427.
Full textAbstract:
Introduction. Environmental safety is one of the main priorities of state policy. It ensures the legal regulation of relations in space activities to strengthen the defense and security of the Russian Federation and further extension of the international cooperation of the Russian Federation. Material and methods. In the fall areas of the stages of the booster rockets, screening studies were carried out to identify the propellant component 1.1-unsymmetrical dimethylhydrazine in atmospheric air (n=14) and drinking water (n=23), determine its metabolite N-nitrosodimethylamine quantitatively in the residents’ blood (n = 90) living in the surveyed areas before the rocket launch (n = 45) and after the launch (n = 45). Also quantitative determination of the N-nitrosodimethylamine metabolite in the residents’ urine in the observation group (n = 108) was performed. For comparison, there was selected a group of residents not related to rocket and space activities (n = 13). Identification and analysis of samples of atmospheric air, drinking water, and biological media (blood, urine) was performed using Agilent 7890A gas chromatograph (USA) with a 5975C quadrupole mass spectrometric detector (MCD) and a capillary column of the HP-FFAP 30m • 0.25mm • 0.25µm series. Results. The study revealed the absence of asymmetric 1.1-dimethylhydrazine in 100% of analyzed atmospheric air samples. During the observation period, the concentrations of N-nitrosodimethylamine in the range of 0.00039 to 0.001 mg/dm3 were found in drinking water samples that did not exceed the hygienic standard (LOCNDMA 0.01 mg/dm3). N-nitrosodimethylamine in a concentration range of 0.00095-0.346 mg/dm3 was determined in the blood samples of the population. The studies revealed that after the rocket launch, the N-NDMA concentration in the blood was 1.8 times higher than the concentration registered before the rocket launch. In the urine sample of the resident living in the surveyed area, N-nitrosodimethylamine was detected with a high degree of reliability according to the essential ion with mass 74 m/z and confirmatory ion of 42 m/z, and the concentration was quantitatively calculated at a level of C N-DMA = 0.23 μg/ml. The detection of N-nitrosodimethylamine in blood and urine, even in trace amounts, indicates the possibility of exposure. Conclusion. Performed comprehensive studies made it possible to prove the relative safety of the ecological situation in the fall areas of the booster rockets that are located close to settlements when considering the environmental pollution with unsymmetrical dimethylhydrazine and can be used for systematic monitoring.