bluuebunny/crossref_metadata_2025 huggingface dataset:
High-Speed Ultrahigh-Resolution OCT of Bruch’s Membrane in Membranoproliferative Glomerulonephritis Type 2
Authors: Adhi Mehreen , Read Sarah P. , Liu Jonathan J. , Fujimoto James G. , Duker Jay S.
Published: November 2014

Membranoproliferative glomerulonephritis (MPGN) type 2 is characterized by electron-dense deposits in the glomerular basement membrane and drusen-like deposits in Bruch’s membrane. Over time, atrophic changes in the retina and retinal pigment epithelium occur, which can progress to choroidal neovascularization (CNV). This report describes a patient with MPGN type 2 who developed progressive loss of vision secondary to CNV. High-speed ultrahigh-resolution optical coherence tomography (UHR-OCT) showed an irregular Bruch’s membrane that measured 10 μm beneath the foveal center. High-speed UHR-OCT can potentially be used to analyze Bruch’s membrane in secondary ocular manifestations of diseases such as MPGN type 2 and primary retinal diseases such as age-related macular degeneration.

[
Ophthalmic Surg Lasers Imaging Retina
. 2014;45:614–617.]
Eduardo Torroja y la International Association for Shell and Spatial Structures (IASS)
Authors: Astudillo R.
Published: November 2014

El legado de Eduardo Torroja no se limita a sus innovadores proyectos, o a sus aportaciones al cálculo y desarrollo del hormigón armado y pretensado. A lo largo de su vida, fundó, o contribuyó a fundar, diversas asociaciones, nacionales e internacionales que, como la IASS (1959), continúan vivas liderando el progreso de la construcción civil y arquitectónica.
La costilla laminar del Instituto de Ciencias de la Construcción Eduardo Torroja (IETcc-CSIC). Levantamiento mediante láser-escáner y evaluación estructural
Authors: Echevarría L. , Garnica C. , Gutiérrez J.
Published: November 2014

La capilla exterior construida en el patio de los Alarifes del Instituto de Ciencias de la Construcción Eduardo Torroja fue concebida en forma de «costilla laminar» en 1969 como símbolo de las posibilidades que la tecnología del hormigón armado ofrecía en aquella época. El resultado fue una lámina de hormigón armado de 10 m de longitud y 6,5 m de altura con espesores que varían entre 6 y 40 cm y definida a partir de una directriz en forma de Lemniscata de Bernoulli.

Este artículo estudia el comportamiento que ha tenido esta estructura 45 años después de su construcción. Se ha utilizado una herramienta novedosa como el láser-escáner para el levantamiento volumétrico de la estructura y la modelización tridimensional para realizar el cálculo mediante MEF. Se ha hecho una evaluación de los desperfectos observados en la lámina, un estudio de las deformaciones sufridas y un análisis de su comportamiento resistente y seguridad estructural. A partir de la investigación realizada puede concluirse que la construcción puede mantenerse en servicio realizando las reparaciones y el mantenimiento adecuados.
Ontogeny and functional histochemistry of the digestive and visual systems and other organs during the larval development of the thick-lipped grey mullet, Chelon labrosus
Authors: Sarasquete Carmen , Ortiz-Delgado Juan B. , Martos-Sitcha J. Antonio , De las Heras Verónica , Yúfera Manuel , Martínez-Rodríguez Gonzalo
Published: November 2014

The main ontogenetic and functional changes of the digestive and visual systems of Chelon labrosus during the first three months from fertilization until 99 days post-hatch (dph) are described. An extended slow growth pattern (3.93%) during the first three weeks of larval life was discernible. A long transitional period of mixed endo-exogenous feeding was noticeable until 13 dph. The majority of organ systems and structures (eye, digestive system, liver, pancreas, thyroid and others) were developed and functional before first feeding (mouth opening at 4 dph). First differentiation of gastric glands was detected at 16 dph, with the appearance of a noticeable pyloric muscular portion or typical gizzard and first developed pyloric caeca from 23 dph. The presence of pinocytotic supranuclear vesicles (5 dph) was still visible in the posterior intestine until the third month of life. The eyes exhibited early differentiation and functionality (pigmentation, first cone-type photoreceptors) during the lecithotrophic phase (2 dph), and development of all typical retinal layers containing different retinal cell types was progressively discernible from 16 dph onwards. From this time, rod photoreceptor precursor cells were incorporated into the basal region of the outer nuclear layer, and increases of two types of photoreceptors (cones and rods) were detected from 23 dph.
Corrosion Analysis in the Electronics Industry of Mexicali Influenced by Atmospheric Factors
Authors: Lopez Badilla Gustavo , Acosta Gómez María Marcella , Montoya Gonzalez Heriberto , Castillo Julio Cesar
Published: November 2014

The generation of aggressive environments in indoor of the electronics industry is concerned to people of the electronics industry of Mexicali. This is influenced by variations of relative humidity and temperature as the most important climatic parameters added to the concentration levels of sulfurs in indoor of industrial plants of this arid zone of the northwest of Mexico. For this reason a study was made determine by a correlation analysis the indices of the climatic and pollution factors to prevent the generation of the corrosion phenomena. This is significant to reduce the bad function of electronic devices and systems in this zone of Mexico. The study was made from July of 2013 to June 2014.
Oxidative stress affects responsiveness to hypotonicity of renal cells
Authors: Morabito Rossana , La Spada Giuseppa , Dossena Silvia , Marino Angela
Published: November 2014

Oxidative stress plays a critical role in the pathophysiology of several kidney diseases and is the consequence of alterations like ischemic events. The regulatory volume decrease (RVD) is an homeostatic response essential to many cells, including renal cells, to counteract changes in the osmolarity of the external medium. The aim of the present work is to verify whether oxidative stress affects RVD in a model of renal cells (human embryonic kidney cells, HEK 293 Phoenix). To accomplish this aim, the experimental procedure consisted in: i) cell culture preparation and treatment with 200 μM H2O2; and ii) measurement of cell volume changes in isotonic conditions or following hypotonic stress. H2O2 added to the extracellular isotonic solution induced a significant reduction in cell volume, and added to the extracellular hypotonic solution dramatically impaired the expected osmotic cell swelling. Pre-incubation of cells in an extracellular isotonic solution containing H2O2 prevented cell from swelling after hypotonic stress application. In conclusion, H2O2 leads to cell shrinkage in isotonic conditions, inhibits the hypotonicity-induced cell swelling and consequently prevents RVD, hypothetically due to an activation of transport pathways determining ion loss and, in turn, water efflux. Cell shrinkage in isotonic conditions is a hallmark of apoptosis and is known as the apoptotic volume decrease.
A revision of communication strategies for effective disaster risk reduction: A case study of the South Durban basin, KwaZulu-Natal, South Africa
Authors: Skinner Chris , Rampersad Renitha
Published: November 2014

The study examined how effective forms of communication are, or could be, impacting themore traditional forms of emergency and disaster management communication throughthe print and electronic media and how an integrated communication strategy involving allstakeholders could prove to be successful. This study was of an exploratory and descriptivenature, using a case study of the South Durban basin to demonstrate how media analysis,community discussions and internal and external evaluations of current practices in use bymajor industrial players in the basin has thus far failed to reach its full potential for effectivedisaster risk reduction. Strongly emerging from this study was the finding that, as a resultof these evaluations, new systems are now being planned to incorporate social media as anintegral part of an overall communication strategy, which could have far-reaching implicationsfor corporate communicators and strategic planners.
The complexity of maladaptation strategies to disasters: The case of Muzarabani, Zimbabwe
Authors: Ncube-Phiri Siduduziwe , Mundavanhu Chipo , Mucherera Blessing
Published: November 2014

Over the past decade disasters have increased both in complexity and multiplicity, worseningthe plight of vulnerable communities the world over. Many communities have devised copingmechanisms to mitigate the impact, but communities such as Muzarabani in Zimbabweremain susceptible to disasters. This article seeks to analyse whether the coping measuresapplied make the communities safe from or vulnerable to disasters. Information was obtainedthrough interviews, questionnaires and observations from four villages in Chadereka in theMuzarabani district. The results of this study indicated that households, government andnon-governmental organisations have come up with different mitigation strategies, suchas growing crops along river beds, livestock production, raised granaries and doorsteps,flood evacuation shelters and other emergency services. Research revealed that althoughviable, some of the strategies increased the community’s vulnerability. This article thereforerecommends sustainable utilisation of resources, and collaborative efforts to address the rootcauses, dynamic pressures and unsafe conditions in order to reduce the vulnerability of poorcommunities to natural disasters.
The spiritual weakness of churches founded by Western missionaries: The cause of the rise of Africa Independent Churches in Zimbabwe with special reference to the Uniting Presbyterian Church in Southern Africa
Authors: Mushayavanhu David , Duncan Graham A.
Published: November 2014

The Presbytery of Zimbabwe (POZ) of the Uniting Presbyterian Church in Southern Africa(UPCSA) has been affected by a drastic exodus of members to African Independent Churches,which is taking advantage of its spiritual weaknesses in its missional endeavour. The spiritual weaknesses which the people of the POZ experiences are a product of the evangelical mode of mission in Zimbabwean society and the failure by both foreign and local personnel tocontextualise the Good News. This article considers the possibility of correcting this stateof affairs. The central issue addressed is how to understand the context and achieve the necessary change.
The Celtic connection with southern Africa: Tracing a genealogy of missionary spirituality
Authors: Kritzinger J.J.
Published: November 2014

It is quite generally accepted that the missionary monks from the Celtic tradition in Ireland and Scotland played a significant role in the Christianisation of Europe during the Dark Ages.This is a story that should not be forgotten. It is also well known that this was preceded by the thorough evangelisation of Ireland and Scotland (and northeast England) itself by these Celtic monks. What is, however, not getting enough attention is the (much later) outreach to southern Africa coming from those same quarters. In this article an effort is made to give credit to this, and to trace the specific spirituality that made all this possible.
The need for leadership in gender justice: Advancing a missiological agenda for the church in Swaziland
Authors: Kaunda Chammah J.
Published: November 2014

Underpinned by missiological thinking, the article argues that, in a context searching for gender justice, the mission of God should begin with making sensitive the consciousness of Swazi church leaders who, in turn, would act as agents for transforming social consciousness.In this process, the leaders become critically aware that they are called to act as prophetic example by adopting a gender-sensibility posture and calling the local church to account forits reluctance and slothfulness in teaching and practicing gender-justice values and ideals as one of the key social organs of the country. In addition, the leaders should become conscious of the fact that they have a wider prophetic missiological task to subversively challenge and wisely remind the State about its social responsibility to advance the socially shared agenda of radically promoting the rights, humanity and dignity of women in its domain.
A Case of Fallopian Tube Adenofibroma: Difficulties Associated with Differentiation from Ectopic Pregnancy
Authors: Fukushima Akimune , Shoji Tadahiro , Tanaka Shino , Sugiyama Toru
Published: November 2014

Benign solid tumors of the fallopian tubes are extremely rare and often difficult to differentiate from tumors associated with adjacent organs or from various inflammatory diseases. Here, we present a patient who was diagnosed with ectopic pregnancy, based on preoperative tests and intraoperative macroscopic findings, but was later diagnosed with a fallopian tube adenofibroma, based on histopathological evidence, and intrauterine pregnancy. Although initial pregnancy test results were positive, no gestational sac (GS) was seen in the uterus and the patient was diagnosed with an ectopic pregnancy and underwent emergency laparoscopic surgery. A 20-mm, fetus-like solid mass was noted inside the GS-like cystic tumor of the left fallopian tube. From histopathological findings, the lesion was identified as a serous fallopian tube adenofibroma. The baby was born healthy with no problems. This case report suggests that fallopian tube adenofibroma should be considered in the differential diagnosis of suspected ectopic pregnancies.
Potential Contribution of Work-Related Psychosocial Stress to the Development of Cardiovascular Disease and Type II Diabetes: A Brief Review
Authors: Krajnak Kristine M.
Published: November 2014

Two of the major causes of death worldwide are cardiovascular disease and Type II diabetes. Although death due to these diseases is assessed separately, the physiological process that is attributed to the development of cardiovascular disease can be linked to the development of Type II diabetes and the impact that this disease has on the cardiovascular system. Physiological, genetic, and personal factors contribute to the development of both these disorders. It has also been hypothesized that work-related stress may contribute to the development of Type II diabetes and cardiovascular disease. This review summarizes some of the studies examining the role of work-related stress on the development of these chronic disorders. Because women may be more susceptible to the physiological effects of work-related stress, the papers cited in this review focus on studies that examined the difference in responses of men or women to work-related stress or on studies that focused on the effects of stress on women alone. Based on the papers summarized, it is concluded that (1) work-related stress may directly contribute to the development of cardiovascular disease by inducing increases in blood pressure and changes in heart rate that have negative consequences on functioning of the cardiovascular system; (2) workers reporting increased levels of stress may display an increased risk of Type II diabetes because they adopt poor health habits (ie, increased level of smoking, inactivity etc), which in turn contribute to the development of cardiovascular problems; and (3) women in high demand and low-control occupations report an increased level of stress at work, and thus may be at a greater risk of negative health consequences.
Pedigree analysis of Polish warmblood horses participating in riding performance tests
Authors: Borowska Alicja , Szwaczkowski Tomasz
Published: November 2014

Borowska, A. and Szwaczkowski, T. 2015. Pedigree analysis of Polish warmblood horses participating in riding performance tests. Can. J. Anim. Sci. 95: 21–29. The aim of this study was to describe the population structure and genetic diversity in Polish warmblood horse population participating in the performance test. The reference population consisted of 596 stallions and 866 mares that participated in stationary performance tests conducted between 2002 and 2011 in Poland. The pedigree data contained 15 452 individuals. Completeness of pedigree information was assessed by two measures: percentage of animals with both parents known and discrete generation equivalent. Individual inbreeding coefficients, coancestry coefficient, individual increase in inbreeding, founder equivalent, founder genome equivalent, effective number of non-founders and genetic diversity loss were estimated to characterize the genetic diversity of the population. The average number of discrete generation equivalents reached 4.50 for observed stallions and 5.04 for mares, which shows good pedigree completeness. Pedigree analysis showed that 34% of the stallions and 44% of mares had inbreeding coefficients above zero. The average coancestry was 0.39% in the whole tested population. Average inbreeding rate of studied populations was very low (0.46%). The effective number of founders was 560. Generally, the inbreeding rate was low; genetic diversity was observed at a constant level for mares and only a small decrease was noticed for stallion. However, further studies are needed in this area.
Postpartum injection with vitamin E and selenium failed to improve the performance of Awassi ewes and their lambs
Authors: Awawdeh M. S. , Talafha A. Q. , Obeidat B. S.
Published: November 2014

Awawdeh, M. S., Talafha, A. Q. and Obeidat, B. S. 2015. Postpartum injection with vitamin E and selenium failed to improve the performance of Awassi ewes and their lambs. Can. J. Anim. Sci. 95: 111–115. The objective of this study was to investigate the effect of vitamin E and Se injection of nursing Awassi ewes on the performance of ewes (body weight change, milk yield, and composition) and their lambs (growth rate and weaning weight). Twenty-eight Awassi ewes were randomly assigned upon lambing to one of two groups; Control (n=13) and Inject (n=15), where ewes received 0 (control) or 15 plus 0.05 mg kg−1BW of vitamin E and Se, respectively (inject). Intramuscular injections were given at 1 and 4 wk postpartum. Body weight (BW) of ewes and their lambs were recorded at lambing and at 2, 4, 6, and 8 wk postpartum. Milk yield and composition were measured at 2, 4, and 6 wk postpartum and somatic cell count (SCC) was evaluated weekly (from lambing through 8 wk). Injecting nursing ewes with vitamin E and Se had no effects (P≥0.10) on BW change of ewes, milk yield and composition, composition yields, or milk SCC. Injecting nursing ewes with vitamin E and Se had no significant effects (P≥0.29) on weaning weight, BW gain, or growth rate of their lambs. Under conditions similar to the current study, injecting nursing Awassi ewes with vitamin E and Se at 1 and 4 wk postpartum was not effective in improving the performance of ewes and their suckling lambs. Such observations could be attributed to the time of supplementation (pre- or post-partum) and/or the adequate basal vitamin E status in ewes.
Effects of different photorespiration inhibitors on photosynthetic characteristics and berry quality of Vitis amurensis Rupr.
Authors: Liu Liyuan , Wang Zhenxing , Zhao Xianhua , Nan Lijun , Nan Hailong , Wang Shan , Li Hua
Published: November 2014

Liu, L., Wang, Z., Zhao, X., Nan, L., Nan, H., Wang, S. and Li, H. 2015. Effects of different photorespiration inhibitors on photosynthetic characteristics and berry quality of Vitis amurensis Rupr. Can. J. Plant Sci. 95: 417–426. The effects of two photorespiration inhibitors on photosynthetic characteristics and berry quality of Vitis amurensis Rupr. were studied. The experiments used V. amurensis variety ‘Shuang hong’ as the experimental grape, NaHSO3 (sodium bisulfite) and isoniazide (INH) as the photorespiration inhibitors with three different spray concentrations, respectively. Results show that both photorespiration inhibitors improved the soluble solids (SS) contents and SS/total acid (TA) ratios (except the 350 mg L−1 INH treatment) in V. amurensis berries; two inhibitors can also improve the concentrations of glucose, sucrose, arabinose, lactose as well as monosaccharides (MS) and MS+disaccharides (DS) contents, and at the same time decrease the TA contents in V. amurensis berries. Meanwhile, all NaHSO3 treatments had higher SS, SS/TA, glucose, and sucrose than treatments with the same concentrations of INH. However, the arabinose contents in all the INH treatments were higher than those in NaHSO3 treatments at the same concentrations. Compared with INH treatments, NaHSO3 were better at increasing net photosythesis rate (Pn), Rubisco carboxylation efficiency (CE), intercellular CO2 concentration (Ci) and decreasing photorespiration rate (Pr). However, the effects of NaHSO3 and INH on fluorescent characteristics of V. amurensis leaves were not significant. The fact that maximal values for photochemical efficiency of photosystem II complex (PSII) in the dark (Fv/Fm) in this study were large indicate that both NaHSO3 and INH had positive effects on chlorophyll fluorescence of V. amurensis leaves, which meant they had the ability to release surplus light energy and mitigate photoinhibition by inhibiting photorespiration at all three concentrations. Comprehensive analysis clearly indicates that NaHSO3 had better effects on photorespiration inhibition and fluorescent characteristics, and improved photosynthesis and the quality of V. amurensis grape berries, especially at 250 mg L−1.
Identification of QTL for seed coat colour and oil content inBrassica napusby association mapping using SSR markers
Authors: Qu Cunmin , Hasan Maen , Lu Kun , Liu Liezhao , Zhang Kai , Fu Fuyou , Wang Min , Liu Shuiyan , Bu Haidong , Wang Rui , Xu Xinfu , Chen Li , Li Jiana
Published: November 2014

Qu, C., Hasan, M., Lu, K., Liu, L., Zhang, K., Fu, F., Wang, M., Liu, S., Bu, H., Wang, R., Xu, X., Chen, L. and Li, J. 2015. Identification of QTL for seed coat colour and oil content in Brassica napus by association mapping using SSR markers. Can. J. Plant Sci. 95: 387–395. Association mapping identifies quantitative trait loci (QTL) based on the strength of linkage disequilibrium (LD) between markers and functional polymorphisms across a set of diverse germplasms. In this study, we used association mapping to detect QTL and genome-wide simple sequence repeat (SSR) markers linked to seed coat colour and oil content in a population of 217 oilseed rape (Brassica napus L.) accessions. We corrected for the population structure of B. napus using 389 genome-wide SSR markers. In total, 25 and 11 SSR markers linked to seed coat colour and oil content were detected, respectively, and these two sets of markers were in different linkage groups. Nine of these markers for seed coat colour spanned the major QTL region for seed coat colour, and been mapped to chromosome A9. Six of these markers showed high levels of association with both seed coat colour and oil content, and markers H081N08.8 and KS20291 were mapped to the major QTL region for seed coat colour on chromosome A9. Another marker, CB10364, was in high LD with all determined seed coat colour and oil content traits, and was mapped to the co-localized QTL region for them on chromosome A8. These data indicate that seed coat colour was found to be an important contributor to seed oil content. Further, we show that association mapping using a heterogeneous set of genotypes is a suitable approach for complementing and enhancing previously obtained QTL information for marker-assisted selection.
Spectral Flow for Nonunital Spectral Triples
Authors: Carey A. L. , Gayral V. , Phillips J. , Rennie A. , Sukochev F. A.
Published: November 2014

We prove two results about nonunital index theory left open in a previous paper. The
first is that the spectral triple arising from an action of the reals on a C*-algebra with invariant trace satisûes the hypotheses of the nonunital local index formula. The second result concerns the meaning of spectral flow in the nonunital case. For the special case of paths arising from the odd index pairing for smooth spectral triples in the nonunital setting, we are able to connect with earlier approaches to the analytic definition of spectral flow
Outer Partial Actions and Partial Skew Group Rings
Authors: Nystedt Patrik , Öinert Johan
Published: November 2014

We extend the classical notion of an outer action α of a group G on a unital ring A to the case when α is a partial action on ideals, all of which have local units. We show that if α is an outer partial action of an abelian group G, then its associated partial skew group ring A *α G is simple if and only if A is G-simple. This result is applied to partial skew group rings associated with two different types of partial dynamical systems.
The Green-Tao theorem: an exposition
Authors: Conlon David , Fox Jacob , Zhao Yufei
Published: November 2014

The celebrated Green-Tao theorem states that the prime numbers contain arbitrarily long arithmetic progressions. We give an exposition of the proof, incorporating several simplifications that have been discovered since the original paper.
Live Music Promotes Positive Behaviours in People with Alzheimer's Disease
Authors: Cox Elissa , Nowak Madeleine , Buettner Petra
Published: November 2014

Introduction:

Behavioural symptoms of Alzheimer's disease present barriers to providing a holistic standard of care. Limited attention has been given to the potential effects of live music, rather than background music or music therapy, on mood, function, and participation in and performance of daily activities. This exploratory study investigated whether live music could facilitate the expression of positive behaviour in people with Alzheimer's disease.

Method:

A live musical violin intervention, provided on a one-to-one basis in a residential care facility, was employed to assess positive behaviour in people with moderate-to-severe Alzheimer's disease using a one-group repeated measures design. Seven participants were video-recorded before, during, and after the intervention, which was provided individually in three separate sessions. The investigator and a blinded assessor used an investigator-modified version of the Cohen-Mansfield Agitation Inventory to assess 16 positive behaviours. Quotations from study participants are presented. Data were analysed using the Friedman test.

Results:

The total number of positive behaviours increased significantly from a median number of 4.3 (range 1.3–13) before the intervention to 30 (range 13–47.7) during, and 24.3 (range 4–27.7) after the intervention (p = 0.001).

Conclusion:

Live individualized music may provide occupational therapists with a useful strategy to enrich the lives of people with Alzheimer's disease.
Occupational Therapy for People Living with a Life-Limiting Illness: A Thematic Review
Authors: Hammill Kathrine , Bye Rosalind , Cook Catherine
Published: November 2014

Introduction:

Little is known about occupational therapy practice for people with a life-limiting illness. This paper aims to review the available occupational therapy literature in order to develop a greater understanding of the role and practice trends of occupational therapists working in this area.

Methods:

A systematic search of literature published from 1975–2013 was conducted. Three hundred and fifty-five pieces of literature were located and screened for inclusion using a three-stage process. All literature that met the inclusion criteria was then analysed thematically.

Findings:

An in-depth review of 52 articles, three position statements, two key occupational texts, and one clinical guideline identified three themes in the literature. These themes comprised: (i) reframing practice: defining a palliative approach in occupational therapy; (ii) continuing occupational engagement despite loss; and (iii) preparing for practice when your client is dying: educational requirements of occupational therapists.

Conclusion:

Occupational therapy has an important role to play in the care of people with a life-limiting illness. However, knowledge gaps remain concerning the scope of the role and how best to engage clients in meaningful occupations at the end of life. Further education is required at the undergraduate level and for clinicians working in this area.
Low temperatures enhance organic nitrate formation: evidence from observations in the 2012 Uintah Basin Winter Ozone Study
Authors: Lee L. , Wooldridge P. J. , Gilman J. B. , Warneke C. , de Gouw J. , Cohen R. C.
Published: November 2014

Abstract. Nitrogen dioxide (NO2) and total alkyl nitrates (ΣANs) were measured using thermal dissociation laser-induced fluorescence during the 2012 Uintah Basin Winter Ozone Study (UBWOS) in Utah, USA. The observed NO2 concentration was highest before sunrise and lowest in the late afternoon, suggestive of a persistent local source of NO2 coupled with turbulent mixing out of the boundary layer. In contrast, ΣANs co-varied with solar radiation with a noontime maximum, indicating that local photochemical production combined with rapid mixing and/or deposition was the dominant factor in determining the ΣAN concentrations. We calculate that ΣANs were a large fraction (~60%) of the HOx free radical chain termination and show that the temperature dependence of the alkyl nitrate yields enhances the role of ΣANs in local chemistry during winter by comparison to what would occur in the warmer temperatures of summer.
Competition between water uptake and ice nucleation by glassy organic aerosol particles
Authors: Berkemeier T. , Shiraiwa M. , Pöschl U. , Koop T.
Published: November 2014

Abstract. Organic aerosol particles play a key role in climate by serving as nuclei for clouds and precipitation. Their sources and composition are highly variable, and their phase state ranges from liquid to solid under atmospheric conditions, affecting the pathway of activation to cloud droplets and ice crystals. Due to slow diffusion of water in the particle phase, organic particles may deviate in phase and morphology from their thermodynamic equilibrium state, hampering the prediction of their influence on cloud formation. We overcome this problem by combining a novel semi-empirical method for estimation of water diffusivity with a kinetic flux model that explicitly treats water diffusion. We estimate timescales for particle deliquescence as well as various ice nucleation pathways for a wide variety of organic substances, including secondary organic aerosol (SOA) from the oxidation of isoprene, α-pinene, naphthalene, and dodecane. The simulations show that, in typical atmospheric updrafts, glassy states and solid/liquid core-shell morphologies can persist for long enough that heterogeneous ice nucleation in the deposition and immersion mode can dominate over homogeneous ice nucleation. Such competition depends strongly on ambient temperature and relative humidity as well as humidification rate and particle size. Due to differences in glass transition temperature, hygroscopicity and atomic O / C ratio of the different SOA, naphthalene SOA particles have the highest potential to act as heterogeneous ice nuclei. Our findings demonstrate that kinetic limitations of water diffusion into organic aerosol particles are likely to be encountered under atmospheric conditions and can strongly affect ice nucleation pathways. For the incorporation of ice nucleation by organic aerosol particles into atmospheric models, our results demonstrate a demand for model formalisms that account for the effects of molecular diffusion and not only describe ice nucleation onsets as a function of temperature and relative humidity but also include updraft velocity, particle size and composition.
Atmospheric oxidation of isoprene and 1,3-butadiene: influence of aerosol acidity and relative humidity on secondary organic aerosol
Authors: Lewandowski M. , Jaoui M. , Offenberg J. H. , Krug J. D. , Kleindienst T. E.
Published: November 2014

Abstract. The effects of acidic seed aerosols on the formation of secondary organic aerosol (SOA) have been examined in a number of previous studies, several of which have observed strong linear correlations between the aerosol acidity (measured as nmol H+ per m3 air sample volume) and the percent change of secondary organic carbon (SOC). The measurements have used several precursor compounds representative of different classes of biogenic hydrocarbons including isoprene, monoterpenes, and sesquiterpenes. To date, isoprene has displayed the most pronounced increase in SOC, although few measurements have been conducted with anthropogenic hydrocarbons. In the present study, we examine several aspects of the effect of aerosol acidity on the secondary organic carbon formation from the photooxidation of 1,3-butadiene, as well as extending the previous analysis of isoprene. The photooxidation products measured in the absence and presence of acidic sulfate aerosols were generated either through photochemical oxidation of SO2 or by nebulizing mixtures of ammonium sulfate and sulfuric acid into a 14.5 m3 smog chamber system. The results showed that, like isoprene and β-caryophyllene, 1,3-butadiene SOC yields linearly correlate with increasing acidic sulfate aerosol. The observed acid sensitivity of 0.11% SOC increase per nmol m−3 increase in H+ was approximately a factor of three less than that measured for isoprene. The results also showed that the aerosol yield decreased with increasing humidity for both isoprene and 1,3-butadiene, although to different degrees. Increasing the absolute humidity from 2 to 12 g m−3 reduced the 1,3-butadiene yield by 45% and the isoprene yield by 85%.
Large-eddy simulations of contrails in a turbulent atmosphere
Authors: Picot J. , Paoli R. , Thouron O. , Cariolle D.
Published: November 2014

Abstract. In this work, the evolution of contrails in the vortex and dissipation regimes is studied by means of fully three-dimensional large-eddy simulation (LES) coupled to a Lagrangian particle tracking method to treat the ice phase. This is the first paper where fine-scale atmospheric turbulence is generated and sustained by means of a stochastic forcing that mimics the properties of stably stratified turbulent flows as those occurring in the upper troposphere lower stratosphere. The initial flow-field is composed by the turbulent background flow and a wake flow obtained from separate LES of the jet regime. Atmospheric turbulence is the main driver of the wake instability and the structure of the resulting wake is sensitive to the intensity of the perturbations, primarily in the vertical direction. A stronger turbulence accelerates the onset of the instability, which results in shorter contrail decent and more effective mixing in the interior of the plume. However, the self-induced turbulence that is produced in the wake after the vortex break-up dominates over background turbulence at the end of the vortex regime and dominates the mixing with ambient air. This results in global microphysical characteristics such as ice mass and optical depth that are be slightly affected by the intensity of atmospheric turbulence. On the other hand, the background humidity and temperature have a first order effect on the survival of ice crystals and particle size distribution, which is in line with recent and ongoing studies in the literature.
Air quality monitoring in communities of the Canadian Arctic during the high shipping season with a focus on local and marine pollution
Authors: Aliabadi A. A. , Staebler R. M. , Sharma S.
Published: November 2014

Abstract. The Canadian Arctic has experienced decreasing sea ice extent and increasing shipping activity in the recent decades. While there are economic incentives to develop resources in the North, there are environmental concerns that increasing marine traffic will contribute to declining air quality in Northern communities. In an effort to characterize the relative impact of shipping on air quality in the North, two monitoring stations have been installed in Cape Dorset and Resolute, Nunavut, and have been operational since 1 June 2013. The impact of shipping and other sources of emissions on NOx, O3, SO2, BC, and PM2.5 pollution have been characterized for the 2013 shipping season from 1 June to 1 November. In addition, a high resolution Air Quality Health Index (AQHI) for both sites was computed. Shipping consistently increased O3 mixing ratio and PM2.5 concentration. The 90% confidence interval for mean difference in O3 mixing ratio between ship and no ship-influenced air masses were up to 4.6–4.7 ppb and 2.5–2.7 ppb for Cape Dorset and Resolute, respectively. The same intervals for PM2.5 concentrations were up to 1.8–1.9 μg m−3 and 0.5–0.6 μg m−3. Ship-influenced air masses consistently exhibited degraded air quality by an increase of 0.1 to 0.3 in the high resolution AQHI compared to no ship-influenced air masses. Trajectory cluster analysis in combination with ship traffic tracking provided an estimated range for percent ship contribution to NOx, O3, SO2, and PM2.5 that were 12.9–17.5%, 16.2–18.1%, 16.9–18.3%, and 19.5–31.7% for Cape Dorset and 1.0–7.2%, 2.9–4.8%, 5.5–10.0%, and 6.5–7.2% for Resolute during the 2013 shipping season. Additional measurements in Resolute suggested that percent ship contribution to black carbon was 4.3–9.8% and that black carbon constituted 1.3–9.7% of total PM2.5 mass in ship plumes. Continued air quality monitoring in the above sites for future shipping seasons will improve the statistics in our analysis as well as characterize repeating seasonal patterns in air quality due to shipping, local pollution, and long-range transport.
Improved retrieval of nitrogen dioxide (NO2) column densities by means of MKIV Brewer spectrophotometers
Authors: Diémoz H. , Siani A. M. , Redondas A. , Savastiouk V. , McElroy C. T. , Navarro-Comas M. , Hase F.
Published: November 2014

Abstract. A new algorithm to retrieve nitrogen dioxide (NO2) column densities using MKIV ("Mark IV") Brewer spectrophotometers is described. The method includes several improvements, such as a more recent spectroscopic data set, the reduction of measurement noise, interference by other atmospheric species and instrumental settings, and a better determination of the zenith sky air mass factor. The technique was tested during an ad hoc calibration campaign at the high-altitude site of Izaña (Tenerife, Spain) and the results of the direct sun and zenith sky geometries were compared to those obtained by two reference instruments from the Network for the Detection of Atmospheric Composition Change (NDACC): a Fourier Transform Infrared Radiometer (FTIR) and an advanced visible spectrograph (RASAS-II) based on the differential optical absorption spectrometry (DOAS) technique. To determine the extraterrestrial constant, an easily implementable extension of the standard Langley technique for very clean sites without tropospheric NO2 was developed which takes into account the daytime linear drift of stratospheric nitrogen dioxide due to photochemistry. The measurement uncertainty was thoroughly determined by using a Monte Carlo technique. Poisson noise and wavelength misalignments were found to be the most influential contributors to the overall uncertainty, and possible solutions are proposed for future improvements. The new algorithm is backward-compatible, thus allowing for the reprocessing of historical data sets.
Tomographic retrieval of water vapour and temperature around polar mesospheric clouds using Odin-SMR
Authors: Christensen O. M. , Eriksson P. , Urban J. , Murtagh D. , Hultgren K. , Gumbel J.
Published: November 2014

Abstract. A special observation mode of the Odin satellite provides the first simultaneous measurements of water vapour, temperature and polar mesospheric cloud (PMC) brightness over a large geographical area while still resolving both horizontal and vertical structures in the clouds and background atmosphere. The observation mode has been activated during June, July and August of 2010, 2011 and 2014, and for latitudes between 50 and 82° N. This paper focuses on the water vapour and temperature measurements carried out with Odin's sub-millimetre radiometer (SMR). The tomographic retrieval approach used provides water vapour and temperature between 75–90 km with a vertical resolution of about 2.5 km and a horizontal resolution of about 200 km. The precision of the measurements is estimated to 0.5 ppm for water vapour and 3 K for temperature. Due to limited information about the pressure at the measured altitudes, the results have large uncertainties (> 3 ppm) in the retrieved water vapour. These errors, however, influence mainly the mean atmosphere retrieved for each orbit, and variations around this mean are still reliably captured by the measurements. SMR measurements are performed using two different mixer chains, denoted as frequency mode 19 and 13. Systematic differences between the two frontends have been noted. A first comparison with the Solar Occultation For Ice Experiment instrument (SOFIE) on-board the Aeronomy of Ice in the Mesosphere (AIM) satellite and the Fourier Transform Spectrometer of the Atmospheric Chemistry Experiment (ACE-FTS) on-board SCISAT indicates that the measurements using the frequency mode 19 have a significant low bias in both temperature (> 20 K) and water vapour (> 1 ppm), while the measurements using frequency mode 13 agree with the other instruments considering estimated errors. PMC brightness data are provided by the OSIRIS, Odin's other sensor. Combined SMR and OSIRIS data for some example orbits are considered. For these orbits, effects of PMCs on the water vapour distribution are clearly seen. Areas depleted of water vapour are found above layers with PMC, while regions of enhanced water vapour due to ice particle sedimentation are primarily placed between and under the clouds.
A comparison between VEGA 1, 2 and Giotto flybys of comet 1P/Halley: implications for Rosetta
Authors: Volwerk M. , Glassmeier K.-H. , Delva M. , Schmid D. , Koenders C. , Richter I. , Szegö K.
Published: November 2014

Abstract. Three flybys of comet 1P/Halley, by VEGA 1, 2 and Giotto, are investigated with respect to the occurrence of mirror mode waves in the cometosheath and field line draping in the magnetic pile-up region around the nucleus. The time interval covered by these flybys is approximately 8 days, which is also the approximate length of an orbit or flyby of Rosetta around comet 67P/Churyumov–Gerasimenko. Thus any significant changes observed around Halley are changes that might occur for Rosetta during one pass of 67P/CG. It is found that the occurrence of mirror mode waves in the cometosheath is strongly influenced by the dynamical pressure of the solar wind and the outgassing rate of the comet. Field line draping happens in the magnetic pile-up region. Changes in nested draping regions (i.e. regions with different Bx directions) can occur within a few days, possibly influenced by changes in the outgassing rate of the comet and thereby the conductivity of the cometary ionosphere.
Efficiency and adaptability of the benthic methane filter at Quepos Slide cold seeps, offshore Costa Rica
Authors: Steeb P. , Krause S. , Linke P. , Hensen C. , Dale A. W. , Nuzzo M. , Treude T.
Published: November 2014

Abstract. Large amounts of methane are delivered by fluids through the erosive forearc of the convergent margin offshore Costa Rica and lead to the formation of cold seeps at the sediment surface. Besides mud extrusion, numerous cold seeps are created by landslides induced by seamount subduction or fluid migration along major faults. Most of the dissolved methane reaching the seafloor at cold seeps is oxidized within the benthic microbial methane filter by anaerobic oxidation of methane (AOM). Measurements of AOM and sulfate reduction as well as numerical modeling of porewater profiles revealed a highly active and efficient benthic methane filter at Quepos Slide site; a landslide on the continental slope between the Nicoya and Osa Peninsula. Integrated areal rates of AOM ranged from 12.9 ± 6.0 to 45.2 ± 11.5 mmol m-2 d-1, with only 1 to 2.5% of the upward methane flux being released into the water column. Additionally, two parallel sediment cores from Quepos Slide were used for in vitro experiments in a recently developed Sediment-F low-Through (SLOT) system to simulate an increased fluid and methane flux from the bottom of the sediment core. The benthic methane filter revealed a high adaptability whereby the methane oxidation efficiency responded to the increased fluid flow within 150–170 days. To our knowledge, this study provides the first estimation of the natural biogeochemical response of seep sediments to changes in fluid flow.
Recycling and fluxes of carbon gases in a stratified boreal lake following experimental carbon addition
Authors: Nykänen H. , Peura S. , Kankaala P. , Jones R. I.
Published: November 2014

Abstract. Partly anoxic stratified humic lakes are important sources of methane (CH4) and carbon dioxide (CO2) to the atmosphere. We followed the fate of CH4 and CO2 in a small boreal stratified lake, Alinen Mustajärvi, during 2007–2009. In 2008 and 2009 the lake received additions of dissolved organic carbon (DOC) with stable carbon isotope ratio (δ13C) around 16‰ higher than that of local allochthonous DOC. Carbon transformations in the water column were studied by measurements of δ13C of CH4 and of the dissolved inorganic carbon (DIC). Furthermore, CH4 and CO2 production, consumption and emissions were estimated. Methane oxidation was estimated by a diffusion gradient method. The amount, location and δ13C of CH4-derived biomass and CO2 in the water column were estimated from the CH4 oxidation pattern and from measured δ13C of CH4. Release of CH4 and CO2 to the atmosphere increased during the study. Methane production and almost total consumption of CH4 mostly in the anoxic water layers, was equivalent to the input from primary production (PP). δ13C of CH4 and DIC showed that hydrogenotrophic methanogenesis was the main source of CH4 to the water column, and methanogenic processes in general were the reasons for the 13C-enriched DIC at the lake bottom. CH4 and DIC became further 13C-enriched in the anoxic layer of the water column during the years of DOC addition. Even gradient diffusion measurements showed active CH4 oxidation in the anoxic portion of the water column; there was no clear 13C-enrichment of CH4 as generally used to estimate CH4 oxidation strength. Increase in δ13C-CH4 was clear between the metalimnion and epilimnion where the concentration of dissolved CH4 and the oxidation of CH4 were small. Thus, 13C-enrichment of CH4 does not reveal the main location of methanotrophy in a lake having simultaneous anaerobic and aerobic oxidation of CH4. Overall the results show that organic carbon is processed efficiently to CH4 and CO2 and recycled in the anoxic layer of stratified boreal lakes by CH4 oxidation. In spite of this, increased DOC input led to increased greenhouse gas release, mainly as CO2 but also as CH4. Due to the predominantly anaerobic CH4 oxidation, a relatively small amount of CH4-derived biomass was produced, while a large amount of CH4-derived CO2 was produced in the anoxic bottom zone of the lake.