bluuebunny/crossref_metadata_2025 huggingface dataset:
Passivation of zero-valent iron by denitrifying bacteria and the impact on trichloroethene reduction in groundwater
Authors: Chen Liang , Jin Song , Fallgren Paul H. , Liu Fei , Colberg Patricia J. S.
Published: March 2013

Zero-valent iron (ZVI) application in groundwater remediation is limited by its vulnerability to passivation, which significantly decreases its surface reactivity. Both biological and chemical processes can potentially passivate ZVI, although the understanding of biological passivation is limited. This study was conducted in bench-scale reactors packed with fresh ZVI or ZVI pre-exposed to nitrate (NO3−) and in the presence or absence of a denitrifying bacterial enrichment (DNBE). The first-order rate coefficients (k) for NO3− reduction by ZVI in the presence and absence of DNBE were 0.20 and 0.09 s−1, respectively, suggesting that both ZVI and microbes contribute to NO3− removal. Abiotic reduction of nitrate was observed in reactors with trichloroethene (TCE) if ZVI was present; however, it resulted in reduced rates of TCE reduction (k = 0.29 s−1) when compared to reactors with fresh ZVI and no nitrate (k = 0.55 s−1). The TCE reduction efficiency decreased by 49% (k = 0.15 s−1) in the presence of DNBE, suggesting that microbial growth on ZVI or catalyzed oxidation of ZVI surface can inhibit TCE reduction by ZVI. Contrary to the presumption that denitrification may decrease ZVI passivation by nitrate, results from this study suggest that denitrifying bacteria actually exacerbate ZVI passivation.
Hydrogen sulfide removal from livestock biogas by a farm-scale bio-filter desulfurization system
Authors: Su J.-J. , Chang Y.-C. , Chen Y.-J. , Chang K.-C. , Lee S.-Y.
Published: March 2013

A farm-scale biogas desulfurization system was designed and tested for H2S removal efficiency from livestock biogas. This work assesses the H2S removal efficiency of a novel farm-scale biogas bio-desulfurization system (BBS) operated for 350 days on a 1,000-head pig farm. Experimental data demonstrated that suitable humidity and temperature can help sulfur-oxidizing bacteria to form active bio-films on the bio-carriers. The daily average removal rate increased to 879.16 from 337.75 g-H2S/d with an average inlet H2S concentration of 4,691 ± 1,532 mg/m3 in biogas. Thus, the overall (0–350 days) average H2S removal efficiency exceeded 93%. The proposed BBS overcomes limitations of H2S in biogas when utilizing pig farm biogas for power generation and other applications.
On (p,1)-total labelling of plane graphs with independent crossings
Authors: Zhang Xin , Liu Guizhen , Yu Yong
Published: March 2013

Two distinct crossings are independent if the end-vertices of the crossed
pair of edges are mutually different. If a graph G has a drawing in the plane
so that every two crossings are independent, then we call G a plane graph
with independent crossings or IC-planar graph for short. In this paper, it is
proved that the (p, 1)-total labelling number of every IC-planar graph G is
at most ?(G) + 2p ? 2 provided that ?(G) ? ? and 1(G) ? 1, where (?, 1) ?
{(6p + 2, 3), (4p + 2, 4), (2p + 5, 5)}. As a consequence, we generalize and
improve some results obtained in [F. Bazzaro, M. Montassier, A. Raspaud, (d,
1)-Total labelling of planar graphs with large girth and high maximum degree,
Discrete Math. 307 (2007) 2141-2151].
On strong double matrix summability via ideals
Authors: Savaş Ekrem
Published: March 2013

In this paper, we define some new double sequence spaces by combining the
notion of ideal, Orlicz function and nonnegative four dimensional matrix. We
make certain investigations on the classes of sequences arising out of this
new summability method. In addition, we shall establish inclusion theorems
between these spaces and other sequence spaces.
Conditional integral transforms with related topics on function space
Authors: Chung Hyun , Choi Jae , Chang Seung
Published: March 2013

In this paper we study the conditional integral transform, the conditional
convolution product and the first variation of functionals on function space.
For our research, we modify the class S? of functionals introduced in [7]. We
then give the existences of the conditional integral transform, the
conditional convolution product and the first variation for functionals in
S?. Finally, we give various relationships and formulas among conditional
integral transforms, conditional convolution products and first variations of
functionals in S?.
On the power graph of a finite group
Authors: Mirzargar M. , Ashrafi A.R. , Nadjafi-Arani M.J.
Published: March 2013

The power graph P(G) of a group G is the graph whose vertex set is the group
elements and two elements are adjacent if one is a power of the other. In
this paper, we consider some graph theoretical properties of a power graph
P(G) that can be related to its group theoretical properties. As consequences
of our results, simple proofs for some earlier results are presented.
The (C, α) integrability of functions by weighted mean methods
Authors: Çanak İbrahim , Totur Ümit
Published: March 2013

Let p(x) be a nondecreasing continuous function on [0, ?) such that p(0) =
0 and p(t) ? ? as t ? ?. For a continuous function f (x) on [0, ?), we
define s(t)= ?0t f(u)du and ?? (t) =?0t? (1- p(u)/p(t))? f(u)du.
We say that a continuous function f (x) on [0, ?) is (C, ?)
integrable to a by the weighted mean method determined by the function p(x)
for some ? > ?1 if the limit limt?? ?? (t) = a exists. We prove that if the
limit limt?? ?? (t) = a exists for some ? > ?1, then the limit limt?? ??+h
(t) = a exists for all h > 0. Next, we prove that if the limit limt?? ?? (t)
= a exists for some ? > 0 and p(t)/p?(t) f(t)= O(1), t ? ?, then the
limit limt?? ???1 (t) = a exists.
Parametric quintic spline solution for sixth order two point boundary value problems
Authors: Khan Arshad , Sultana Talat
Published: March 2013

In this paper, parametric quintic spline method is presented to solve a
linear special case sixth order two point boundary value problems with two
different cases of boundary conditions. The method presented in this paper
has been shown to be second and fourth order accurate. Boundary equations
are derived for both the cases of boundary conditions. Convergence analysis
of these methods are discussed. The presented method is tested on four
numerical examples of linear sixth order boundary value problems. Comparison
is made to show the practical usefulness of the presented method.
Bicyclic graphs with minimal values of the detour index
Authors: Kovijanic-Vukicevic Zana , Bozovic Vladimir
Published: March 2013

We are looking for the graphs with minimal detour index in the class of
connected bicyclic graphs. For the fixed number of vertices, we split the
problem into two cases: bicyclic graphs without common edges between cycles
and the complement of it. In both cases, we find graphs with minimal detour
index.
Note on selection principles of Kocinac
Authors: Djurcic Dragan , Zizovic Malisa , Petojevic Aleksandar
Published: March 2013

This paper investigates ?di, i? {2,3,4}, selection principles (which are
modification of known selection principles of Kocinac) on a double sequence
of double sequences of real numbers which converge to a point a?R in
Pringsheim?s sense. A stronger result than one given in [6] will be proved
for the ?d2 selection principle. Also, two more propositions will be proved
for the Sd1 and S?1 selection principles, which 11 are also improvements of
results given in [6].
Urban policy in Brazil: Mismatches in the social management of land appreciation
Authors: Neto Paulo , Moreira Tomás
Published: March 2013

In Brazil, there is a clear strengthening of debates about the instruments of
City Statute, which are discussed under the light of social management of
land appreciation. Their degree of effectiveness, their low popular
participation and their use to legitimize policies engendered by particular
interests are usually questioned. This paper investigates the capacity of
Joint Urban Operations as a instrument for surplus land value recovery.
Starting from a study on Faria Lima Urban Operation, limitations and
opportunities of Linha Verde Urban Operation (Curitiba-PR), which is being
implemented, is prospectively discussed. Analysis performed came up with
observations that were, at the same time, complementary and contradictory. On
one hand, it is necessary to recognize urban operation?s potential as an
instrument able to leverage urban transformation, dividing costs of public
action among other stakeholders. On the other hand, however, its low
efficiency - from the perspective of social management of land appreciation -
is clear, and shows a lack of mechanisms that could ensure a minimal
addressing of the funds for constructions of public interest.
Spatial-functional organization of settlements in Vojvodina
Authors: Krunic Nikola
Published: March 2013

This paper summarizes the results of recent exploration of spatial and
functional organization of Autonomous Province of Vojvodina in the Republic
of Serbia (hereinafter referred to as ?Vojvodina?) based on identification of
the level of development of spatial and functional connections and
relationships within its settlement network. The research is theoretically
and methodically based on principles of regionalization and recent doctrines
of regional development, contemporary spatial planning and social and
economics disciplines of social geography. Results to a great extent identify
and scientifically explain problems of the development of spatial and
functional organization of settlement network in Vojvodina. Based on these
results, a recommendation for a possible model of a sustainable settlement
network in Vojvodina has been given.
MultiObjective Genetic Modified Algorithm (MOGMA)
Authors: Vandeva Elica
Published: March 2013

Multiobjective optimization based on genetic algorithms and Pareto based approaches in solving multiobjective optimization problems is discussed in the paper. A Pareto based fitness assignment is used − non-dominated ranking and movement of a population towards the Pareto front in a multiobjective optimization problem. A MultiObjective Genetic Modified Algorithm (MOGMA) is proposed, which is an improvement of the existing algorithm.
Sexual Coercion Risk and Women’s Sport Participation
Authors: Brown Elise , Spiller Laura , Stiles Beverly , Kilgore Lon
Published: March 2013

Sexual coercion affects approximately 58% of college-age females. Victims of sexual coercion often share similar characteristics, such as lower self-esteem, lower assertiveness, higher depressive symptoms, higher alcohol use, increased number of sexual partners, more romantic relationships, prior victimization, and relationship insecurity. Female athletes, on the other hand, have in common such protective factors as higher self-esteem, higher assertiveness, lower alcohol use, and fewer sexual partners. These, then, are assumed to guard against sexual coercion. The purpose of this study was to determine if female athletes were at a lower risk for sexual coercion and whether differences existed in levels of assertiveness, sexual assertiveness, self-esteem, sexual esteem, alcohol use, and the number of sexual partners. Participants included 174 college females (aged 19.94 ± 1.87 years). Participants were identified as an athlete if they reported a history of at least three years of athl iation etic involvement and described themselves as either a high school athlete or having participated in competitive sports (n=125). From among all the participants, 49 were classified as non-athletes. Data demonstrated no differences in either forced or coerced sexual contact history. Athletes and nonathletes differed neither in global nor sexual self-esteem, nor did they differ in global or sexual assertiveness. There was a significant difference across the groups in alcohol use: athletes scored higher on the AUDIT than non-athletes. The number of years of sport involvement positively correlated with the level of alcohol use. Athletes and non-athletes reported similar numbers of sexual partners. The findings of this study imply that athletics may indirectly place females at risk for sexual coercion through an assocwith higher alcohol use.
Microorganisms Associated with Valencia Peanut Affected by Pod Rot in New Mexico
Authors: Sanogo S. , Puppala N.
Published: March 2013

Pod rot of peanut is a disease that occurs worldwide. Soilborne pathogens typically causing pod rot include Rhizoctonia solani, Sclerotium rolfsii, and Pythium spp. Although pod rot is known to occur in New Mexico, no etiological study has been conducted on this disease. In 2005 and 2006, 14 Valencia peanut fields were surveyed in eastern New Mexico where the majority of Valencia peanut is produced. The primary focus of the study was to isolate and identify microorganisms associated with pod rot. The secondary focus of the study was to characterize microorganisms from roots and stems from the same plants selected for pod rot assessment. Peanut plants were collected and processed for isolation of microorganisms by plating seeds, pieces of hull, root, and stem on acidified potato dextrose agar. In both years, the average incidence of pods with hull discoloration or pod rot symptoms varied from 55–60 to over 90%, and disease severity ranged from 5 to over 90% across all fields surveyed. A diverse group of microorganisms representing more than 10 fungal and Oomycete genera were recovered from all plant part tissues, with R. solani as the most predominantly isolated mycelial microorganism. Rhizoctonia solani was found in all fields with average frequency of isolation from approximately 20 to 27% for pod tissue, 19 to 36% for root, and 20 to 27% for stem. In controlled-environment studies, all isolates of R. solani from different plant parts were shown to be pathogenic to Valencia peanut. This etiological study is the first in New Mexico to provide an insight into microorganisms associated with peanut affected by pod rot. Breeding Valencia peanuts for resistance to Rhizoctonia pod rot should be a priority.
Registration of ‘WB9879CLP’ Hard Red Spring Wheat
Authors: Blake N. K. , Clark D. , Lanning S. P. , Carlson G. R. , Lamb P. F. , Nash D. , Wichman D. M. , Kephart K. D. , Stougaard R. N. , Miller J. , Eckhoff J. L. , Menalled F. , Davis E. , Talbert L. E.
Published: March 2013

‘WB9879CLP’ hard red spring wheat (Triticum aestivum L.) (Reg. No. CV‐1086, PI 666046) was developed by the Montana Agricultural Experiment Station and released in 2012 to the commercial partner Westbred, a subsidiary of Monsanto. WB9879CLP is a two‐gene Clearfield wheat for use with the imidazolinone herbicide Beyond (BASF). WB9879CLP was developed by backcrossing alleles for resistance to the imidazolinone herbicide class into the recurrent parent ‘Choteau’. Choteau has solid stems, which provide resistance to the wheat stem sawfly (Cephus cinctus Nort.). The wheat stem sawfly is a major yield‐reducing pest in large areas of Montana and surrounding regions. Alleles for herbicide resistance at TaAHAS1D and TaAHAS1B were selected during the backcrossing process and line derivation using polymerase chain reaction markers developed by BASF. Two years of replicated yield trials at a total of 16 sites showed that WB9879CLP is similar to Choteau in most agronomic characteristics. WB9879CLP showed no symptoms of damage at any of 13 testing sites when imidazolinone herbicide was applied at two times the recommended rate. WB9879CLP is the first Clearfield solid‐stem wheat variety for sawfly infested sites in Montana and adjoining regions.
Architecture and Knowledge-Driven Self-Adaptive Security in Smart Space
Authors: Evesti Antti , Suomalainen Jani , Ovaska Eila
Published: March 2013

Dynamic and heterogeneous smart spaces cause challenges for security because it is impossible to anticipate all the possible changes at design-time. Self-adaptive security is an applicable solution for this challenge. This paper presents an architectural approach for security adaptation in smart spaces. The approach combines an adaptation loop, Information Security Measuring Ontology (ISMO) and a smart space security-control model. The adaptation loop includes phases to monitor, analyze, plan and execute changes in the smart space. The ISMO offers input knowledge for the adaptation loop and the security-control model enforces dynamic access control policies. The approach is novel because it defines the whole adaptation loop and knowledge required in each phase of the adaptation. The contributions are validated as a part of the smart space pilot implementation. The approach offers reusable and extensible means to achieve adaptive security in smart spaces and up-to-date access control for devices that appear in the space. Hence, the approach supports the work of smart space application developers.
Hawking and Unruh Effects of a 5-Dimensional Minimal Gauged Supergravity Black Hole by a Global Embedding Approach
Authors: Zhao Hui-Hua , Zhang Li-Chun , Li Guang-Liang
Published: March 2013

Using the new global embedding approach we investigate Unruh/Hawking temperature of the 5-dimensional minimal gauged supergravity black hole with double rotating parameters in a general (1 + 1) space-time. Our results verify that views of Banerjee and Majhi, and extend this approach to a higher dimension situation.
Quinacridone-Diketopyrrolopyrrole-Based Polymers for Organic Field-Effect Transistors
Authors: Akita Masahiro , Osaka Itaru , Takimiya Kazuo
Published: March 2013

Incorporation of pigment or dye molecules as building units is of great interest in the development of semiconducting polymers, due to their strong intermolecular interactions arising from the strong local dipoles in the unit structure, which would facilitate the charge transport property. In this paper, semiconducting polymers based on well-known pigments, namely, quinacridone and diketopyrrolopyrrole, are synthesized and characterized. The π-stacking distances are found to be 3.5–3.8 Å, which is fairly narrow for semiconducting polymers, indicating that they possess strong intermolecular interactions. Interestingly, polymer orientation is influenced by the composition of alkyl side chains. While the edge-on orientation is observed when the linear alkyl groups are introduced for all the side chains, the face-on orientation is observed when the branched alkyl groups are introduced either in the quinacridone or diketopyrrolopyrrole unit. It is found that the electronic structure of the present polymers is mostly affected by that of the diketopyrrolopyrrole unit, as evidenced by the absorption spectra and computation. Although the field-effect mobility of the polymers is modest, i.e., in the order of 10−4–10−3 cm2/Vs, these findings could be important information for the development of semiconducting polymers.
The Future of the Food System: Cases Involving the Private Sector in South Africa
Authors: Pereira Laura
Published: March 2013

The food system is facing unprecedented pressure from environmental change exacerbated by the expansion of agri-food corporations that are consolidating their power in the global food chain. Although Africa missed the Green Revolution and the wave of supermarket expansion that hit the West and then spread to Asia and Latin America, this is unlikely to continue. With a large proportion of sub-Saharan African countries’ GDP still heavily reliant on agriculture, global trends in agri-food business are having an increasing impact on African countries. South Africa, a leader in agribusiness on the continent, has a well-established agri-food sector that is facing increasing pressure from various social and environmental sources. This paper uses interview data with corporate executives from South African food businesses to explore how they are adapting to the dual pressures of environmental change and globalisation. It shows that companies now have to adapt to macro-trends both within and outside the formal food sector and how this in turn has repercussions for building sustainable farming systems—both small and large-scale. It concludes with the recognition that building a sustainable food system is a complex process involving a diversity of actors, however changes are already being seen. Businesses have strategically recognised the need to align the economic bottom line with social and environmental factors, but real sustainability will only happen when all stakeholders are included in food governance.
A Connectivist Perspective of the Transition from Face-to-Face to Online Teaching in Higher Education
Authors: Cowan Pamela
Published: March 2013

Existing research shows a slow transition to online education by many university teaching staff. A mixed methods approach is used to survey teacher educators in three jurisdictions in the UK who have made the transition to online teaching, followed by focus group and individual interviews to triangulate the data. The eight tenets of connectivism are used as a lens for analysis. Findings reveal sound pedagogical reasons for the limited choice of online tools and tutors highlight two elements, namely, self-fulfilment and their desire to continually develop as an educator, as the rationale for adopting informal professional development in the 21st century.
H.G. Stoker (1999–1993) as Christelike filosoof: ’n Historiese legende en ikoon, of nog steeds ’n kontemporêre mentor?
Authors: Van der Walt Barend J.
Published: March 2013

’n Tradisie, wat ’n filosofiese tradisie insluit, kan alleen lewend bly as die verhaal daarvan aan die jonger geslag oorvertel word. Daarom bied hierdie inleidende en oorsigtelike artikel aan die leser iets oor die unieke filosofie van die Suid-Afrikaanse denker, Henk Stoker. Ter inleiding behandel dit die moontlike redes waarom sy denke in Suid-Afrika en elders vandag relatief onbekend is en minder invloedryk was in vergelyking met dié van die twee ander vaders van ’n reformatoriese filosofie, naamlik Dirk H.Th. Vollenhoven en veral Herman Dooyeweerd. Daarna word aandag geskenk aan die Suid-Afrikaanse milieu waarbinne sy filosofie gebore is. Die moontlike interne en eksterne teologiese en filosofiese invloede van veral Herman Bavinck (1854–1921) en Max Scheler (1874–1928) word behandel. Vervolgens word op enkele van Stoker se oorspronklikste bydraes tot die Christelik-filosofiese tradisie gewys. ’n Vlugtige blik word op die wedersydse kritiek tussen Stoker, Dooyeweerd en sekere leerlinge van Dooyeweerd gewerp. Ten slotte kan daar, in die lig van hierdie onderlinge verskille, sekere wanopvattings reggestel word, byvoorbeeld dat ’n Reformatoriese filosofie ’n statiese en geslote sisteem is. H.G. Stoker (1899–1993) as Christian philosopher: historical legend and icon, or still a contemporary mentor? Tradition which includes a philosophical tradition, can only been kept alive when its story is told to younger generations. This is the motivation behind this introductory overview of the unique philosophy of the South African philosopher, Henk Stoker. In comparison with the two other founders of a reformational philosophy, Dirk H.Th. Vollenhoven (1892–1978) and especially Herman Dooyeweerd (1994–1977), Stoker’s ideas are in South Africa, as well as abroad, less well-known among reformed people. The introductory part of this article, therefore, investigates the possible reasons for the relatively small impact of his thinking. The next section requires attention for the South African context in which his Christian philosophy was born. This is followed by a detailed discussion of the possible internal and external theological and philosophical influences of especially Herman Bavinck (1865–1921) and Max Scheler (1874–1928) on the emergence of Stoker’s philosophy of the idea of creation. A few of Stoker’s original contributions to a Christian philosophy are then highlighted. Next the debate between Stoker and Dooyeweerd and some of Dooyeweerd’s followers is reviewed. Finally, in the light of these differences between two of the fathers of the triumvirate already at the origin of a Reformational philosophy, the misconception that this kind of philosophy is a static and closed system, should be corrected.
Preliminary assessment of the gender aspects of disaster vulnerability and loss of human life in South Africa
Authors: Tandlich Roman , Chirenda Tatenda G. , Srinivas Chandra S.S.
Published: March 2013

South Africa has reached a medium level of human development and has a heterogeneous situation with respect to disaster risk management. In this article, a preliminary assessment of the gender aspects of disaster vulnerability and fatalities is presented. The United Nations, the Health Systems Trust and Statistics South Africa were used as data sources for the following gender-segregated values: the life expectancy at birth, unemployment rates, the human development index values, the maternal mortality rates and the number of deaths from unnatural and non-natural causes. The relevant inequality indices were then calculated and used to draw conclusions regarding the gender aspects of disaster risk management in South Africa. Results of the calculations indicate that between 1980 and 2011 men were 10% more vulnerable with respect to their health status. However, the gender differences have been decreasing in recent years. Access of women to healthcare is decreasing with time, potentially decreasing the recovery potential of whole families. Women are more economically vulnerable than men in South Africa, as they are 16.3% – 33% more likely to be unemployed than men. Educational status of both genders in South Africa is comparable based on literacy and enrolment rates at primary and secondary level. On the other hand, men are five times more likely to suffer fatal injuries during disasters.
An Empirical Evaluation of normalization Methods for MicroRNA Arrays in a Liposarcoma Study
Authors: Qin Li-Xuan , Tuschl Tom , Singer Samuel
Published: March 2013

Background

Methods for array normalization, such as median and quantile normalization, were developed for mRNA expression arrays. These methods assume few or symmetric differential expression of genes on the array. However, these assumptions are not necessarily appropriate for microRNA expression arrays because they consist of only a few hundred genes and a reasonable fraction of them are anticipated to have disease relevance.

Methods

We collected microRNA expression profiles for human tissue samples from a liposarcoma study using the Agilent microRNA arrays. For a subset of the samples, we also profiled their microRNA expression using deep sequencing. We empirically evaluated methods for normalization of microRNA arrays using deep sequencing data derived from the same tissue samples as the benchmark. Results: In this study, we demonstrated array effects in microRNA arrays using data from a liposarcoma study. We found moderately high correlation between Agilent data and sequence data on the same tumors, with the Pearson correlation coefficients ranging from 0.6 to 0.9. Array normalization resulted in some improvement in the accuracy of the differential expression analysis. However, even with normalization, there is still a significant number of false positive and false negative microRNAs, many of which are expressed at moderate to high levels.

Conclusions

Our study demonstrated the need to develop more efficient normalization methods for microRNA arrays to further improve the detection of genes with disease relevance. Until better methods are developed, an existing normalization method such as quantile normalization should be applied when analyzing microRNA array data.
Space-Time Discontinuous Galerkin Method for Maxwell’s Equations
Authors: Xie Ziqing , Wang Bo , Zhang Zhimin
Published: March 2013

A fully discrete discontinuous Galerkin method is introduced for solving time-dependent Maxwell’s equations. Distinguished from the Runge-Kutta discontinuous Galerkin method (RKDG) and the finite element time domain method (FETD), in our scheme, discontinuous Galerkin methods are used to discretize not only the spatial domain but also the temporal domain. The proposed numerical scheme is proved to be unconditionally stable, and a convergent rate is established under the L2-norm when polynomials of degree atmost r and k are used for temporal and spatial approximation, respectively. Numerical results in both 2-D and 3-D are provided to validate the theoretical prediction. An ultra-convergence of order in time step is observed numerically for the numerical fluxes w.r.t. temporal variable at the grid points.
Spotted Fever Group Rickettsia in Small Rodents from Areas of Low Endemicity for Brazilian Spotted Fever in the Eastern Region of Minas Gerais State, Brazil
Authors: Milagres Bruno S. , Padilha Amanda F. , Montandon Carlos E. , Freitas Renata N. , Pacheco Richard , Walker David H. , Labruna Marcelo B. , Mafra Cláudio L. , Galvão Márcio A. M.
Published: March 2013

We investigated the humoral immune response against different species of Rickettsia in serum samples from small rodents collected in two areas of a silent focus for Brazilian spotted fever in the eastern region of Minas Gerais State, Brazil. Sera samples were analyzed by indirect immunofluorescence assay using antigens from Rickettsia species of the spotted fever, ancestral, and transition groups. Titers ≥ 1:64 were considered positive. In Santa Cruz do Escalvado, 94% (30 of 32) of the samples collected from Rattus rattus, 22% (5 of 23) from Nectomys squamipes, and 80% (4 of 5) from Akodon sp., reacted by indirect immunofluorescence assay with Rickettsia antigens of the spotted fever group. In the municipality of Pingo D'Água, 84% (26 of 31) of the samples collected from R. rattus, 86% (6 of 7) of the samples from Oryzomys subflavus, 86% (6 of 7) from N. squamipes, and 100% (1 of 1) from Bolomys sp. contained antibodies that reacted with rickettsial antigens of the spotted fever group. These results demonstrated the previous exposure of small rodents to spotted fever group Rickettsia, suggesting the participation of these animals in the natural history of these rickettsiae in this region.
Investigating relationships between aerosol optical depth and cloud fraction using satellite, aerosol reanalysis and general circulation model data
Authors: Grandey B. S. , Stier P. , Wagner T. M.
Published: March 2013

Abstract. Strong positive relationships between cloud fraction (fc) and aerosol optical depth (τ) have been reported. Data retrieved from the MODerate resolution Imaging Spectroradiometer (MODIS) instrument show positive fc–τ relationships across most of the globe. A global mean fc increase of approximately 0.2 between low and high τ conditions is found for both ocean and land. However, these relationships are not necessarily due to cloud–aerosol interactions. Using state-of-the-art Monitoring Atmospheric Composition and Climate (MACC) reanalysis-forecast τ data, which should be less affected by retrieval artefacts, it is demonstrated that a large part of the observed fc–τ signal may be due to cloud contamination of satellite-retrieved τ. For longer MACC forecast time steps of 24 h, which likely contain less cloud contamination, some negative fc–τ relationships are found. The global mean fc increase between low and high τ conditions is reduced to 0.1, suggesting that cloud contamination may account for approximately one half of the satellite-retrieved increase in fc. ECHAM5-HAM general circulation model (GCM) simulations further demonstrate that positive fc–τ relationships may arise due to covariation with relative humidity. Widespread negative simulated fc–τ relationships in the tropics are shown to arise due to scavenging of aerosol by convective precipitation. Wet scavenging events are likely poorly sampled in satellite-retrieved data, because the properties of aerosol below clouds cannot be retrieved. Quantifying the role of wet scavenging, and assessing GCM representations of this important process, remains a challenge for future observational studies of aerosol–cloud–precipitation interactions.
Remote sensing of ice crystal asymmetry parameter using multi-directional polarization measurements – Part 2: Application to the Research Scanning Polarimeter
Authors: van Diedenhoven B. , Cairns B. , Fridlind A. M. , Ackerman A. S. , Garrett T. J.
Published: March 2013

Abstract. A new method to retrieve ice cloud asymmetry parameters from multi-directional polarized reflectance measurements is applied to measurements of the airborne Research Scanning Polarimeter (RSP) obtained during the CRYSTAL-FACE campaign in 2002. The method assumes individual hexagonal ice columns and plates serve as proxies for more complex shapes and aggregates. The closest fit is searched in a look-up table of simulated polarized reflectances computed for cloud layers that contain individual, randomly oriented hexagonal columns and plates with a virtually continuous selection of aspect ratios and distortion. The asymmetry parameter, aspect ratio and distortion of the hexagonal particle that leads to the best fit with the measurements are considered the retrieved values. Two cases of thick convective clouds and two cases of thinner anvil cloud layers are analyzed. Median asymmetry parameters retrieved by the RSP range from 0.76 to 0.78, and are generally smaller than those currently assumed in most climate models and satellite retrievals. In all cases the measurements indicate roughened or distorted ice crystals, which is consistent with previous findings. Retrieved aspect ratios in three of the cases range from 0.9 to 1.6, indicating compact particles dominate the cloud-top shortwave radiation. Retrievals for the remaining case indicate plate-like ice crystals with aspect ratios around 0.3. The RSP retrievals are qualitatively consistent with the CPI images obtained in the same cloud layers. Retrieved asymmetry parameters are compared to those determined in situ by the Cloud Integrating Nephelometer (CIN). For two cases, the median values of asymmetry parameter retrieved by CIN and RSP agree within 0.01, while for the two other cases RSP asymmetry parameters are about 0.03–0.05 greater than those obtained by the CIN. Part of this bias might be explained by vertical variation of the asymmetry parameter or ice shattering on the CIN probe, or both.
In situ detection of electrified aerosols in the upper troposphere and in the stratosphere
Authors: Renard J.-B. , Tripathi S. N. , Michael M. , Rawal A. , Berthet G. , Fullekrug M. , Harrison R. G. , Robert C. , Tagger M. , Gaubicher B.
Published: March 2013

Abstract. Electrified aerosols have been observed in the lower troposphere and in the mesosphere, but have never been detected in the stratosphere and upper troposphere. We present measurements of aerosols during a balloon flight to an altitude of ~24 km. The measurements were performed with an improved version of the STAC aerosol counter dedicated to the search for charged aerosols. It is found that most of the aerosols are charged in the upper troposphere for altitudes below 10 km and in the stratosphere for altitudes above 20 km. On the contrary, the aerosols seem to be uncharged between 10 km and 20 km. Model calculations are used to quantify the electrification of the aerosols with a stratospheric aerosol-ion model. The percentages of charged aerosols obtained with model calculations are in excellent agreement with the observations below 10 km and above 20 km. On the other hand, the model cannot reproduce the absence of detected electrification in the lower stratosphere, such that a distinct unknown process in this altitude range inhibits electrification. The presence of sporadic transient layers of electrified aerosol in the upper troposphere and in the stratosphere could have significant implications for sprite formation.
Ozone trends derived from the total column and vertical profiles at a northern mid-latitude station
Authors: Nair P. J. , Godin-Beekmann S. , Kuttippurath J. , Ancellet G. , Goutail F. , Pazmiño A. , Froidevaux L. , Zawodny J. M. , Evans R. D. , Pastel M.
Published: March 2013

Abstract. The trends and variability of ozone are assessed over a northern mid-latitude station, Haute-Provence Observatory (OHP – 43.93° N, 5.71° E), using total column ozone observations from the Dobson and Système d'Analyse par Observation Zénithale spectrometers, and stratospheric ozone profile measurements from Light detection and ranging, ozonesondes, Stratospheric Aerosol and Gas Experiment II, Halogen Occultation Experiment and Aura Microwave Limb Sounder. A multi-variate regression model with quasi biennial oscillation (QBO), solar flux, aerosol optical thickness, heat flux, North Atlantic oscillation (NAO) and piecewise linear trend (PWLT) or Equivalent Effective Stratospheric Chlorine (EESC) functions is applied to the ozone anomalies. The maximum variability of ozone in winter/spring is explained by QBO and heat flux in 15–45 km and in 15–24 km, respectively. The NAO shows maximum influence in the lower stratosphere during winter while the solar flux influence is largest in the lower and middle stratosphere in summer. The total column ozone trends estimated from the PWLT and EESC functions are of −1.39±0.26 and −1.40±0.25 DU yr−1, respectively over 1984–1996 and about 0.65±0.32 and 0.42±0.08 DU yr−1, respectively over 1997–2010. The ozone profiles yield similar and significant EESC-based and PWLT trends in 1984–1996 and are about −0.5 and −0.8 % yr−1 in the lower and upper stratosphere, respectively. In 1997–2010, the EESC-based and PWLT trends are significant and of order 0.3 and 0.1 % yr−1, respectively in the 18–28 km range, and at 40–45 km, EESC provides significant ozone trends larger than the insignificant PWLT results. Therefore, this analysis unveils ozone recovery signals from total column ozone and profile measurements at OHP, and hence in the mid-latitudes.
Self-limited uptake of α-pinene-oxide to acidic aerosol: the effects of liquid-liquid phase separation and implications for the formation of secondary organic aerosol and organosulfates from epoxides
Authors: Drozd G. T. , Woo J. L. , McNeill V. F.
Published: March 2013

Abstract. The reactive uptake of α-pinene oxide (αPO) to acidic sulfate aerosol was studied under humid conditions in order to gain insight into the effects of liquid-liquid phase separation on aerosol heterogeneous chemistry and further elucidate the formation of secondary organic aerosol and organosulfates from epoxides. A continuous flow environmental chamber was used to monitor changes in diameter of monodisperse, deliquesced, acidic sulfate particles exposed to αPO at 30 and 50% RH. In order to induce phase separation and probe potential limits to particle growth from acidic uptake, αPO was introduced over a wide range of concentrations, from 200 ppb to 5 ppm. Uptake was observed to be highly dependent on initial aerosol pH. Significant uptake of αPO to aerosol was observed with initial pH < 0. When exposed to 200 ppb αPO, aerosol with pH = −1 doubled in volume, and 6% volume growth was observed at pH = 0. Aerosol with pH = 1 showed no growth. The extreme acidity required for efficient αPO uptake suggests that this chemistry is typically not a major route to formation of aerosol mass or organosulfates in the atmosphere. Partition coefficients (Kp) ranged from 0.2–1.6 × 10−4 m3 μg−1 and were correlated to initial particle acidity and particle organic content; particles with higher organic content had lower partition coefficients. Effective uptake coefficients (γ) ranged from 0.4 to 4.7 × 10−5 and are much lower than recently reported for uptake to bulk solutions. In experiments in which αPO was added to bulk H2SO4 solutions, phase separation was observed for mass loadings similar to those observed with particles, and product distributions were dependent on acid concentration. Liquid-liquid phase separation in bulk experiments, along with our observations of decreased uptake to particles with the largest growth factors, suggest an organic coating forms upon uptake to particles, limiting reactive uptake.
Validation of stratospheric and mesospheric ozone observed by SMILES from International Space Station
Authors: Kasai Y. , Sagawa H. , Kreyling D. , Suzuki K. , Dupuy E. , Sato T. O. , Mendrok J. , Baron P. , Nishibori T. , Mizobuchi S. , Kikuchi K. , Manabe T. , Ozeki H. , Sugita T. , Fujiwara M. , Irimajiri Y. , Walker K. A. , Bernath P. F. , Boone C. , Stiller G. , von Clarmann T. , Orphal J. , Urban J. , Murtagh D. , Llewellyn E. J. , Degenstein D. , Bourassa A. E. , Lloyd N. D. , Froidevaux L. , Birk M. , Wagner G. , Schreier F. , Xu J. , Vogt P. , Trautmann T. , Yasui M.
Published: March 2013

Abstract. We observed the diurnal variation of ozone (O3) in the vertical region between 250 and 0.0005 hPa (~12–96 km) using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the Japanese Experiment Module (JEM) of the International Space Station (ISS) between 12 October 2009 and 21 April 2010. The new 4 K superconducting heterodyne receiver technology of SMILES allowed us to obtain a one order of magnitude better signal-to-noise ratio for the O3 line observation compared to past spaceborne microwave instruments. We assessed the quality of the vertical profiles of O3 in the 100–0.001 hP (~16–90 km) region for the SMILES NICT Level 2 product version 2.1.5. The evaluation is based on four components; error analysis; internal comparisons of observations targeting three different instrumental setups for the same O3 625.371 GHz transition; internal comparisons of two different retrieval algorithms; and external comparisons for various local times with ozonesonde, satellite and balloon observations (ENVISAT/MIPAS, SCISAT/ACE-FTS, Odin/OSIRIS, Odin/SMR, Aura/MLS, TELIS). SMILES O3 data have an estimated absolute accuracy of better than 0.3 ppmv (3%) with a vertical resolution of 3–4 km over the 60 to 8 hPa range. The random error for a single measurement is better than the estimated systematic error, being less than 1, 2, and 7%, in the 40–1, 80–0.1, and 100–0.004 hPa pressure region, respectively. SMILES O3 abundance was 10–20% lower than all other satellite measurements at 8–0.1 hPa due to an error arising from uncertainties of the tangent point information and the calibration problem for the intensity of the spectrum. The non sun-synchronous orbit of the ISS allowed us to observe O3 at various local times. A two month period is required to accumulate measurements covering 24 h in local time. However such a dataset can also contain variation due to dynamical, seasonal, and latitudinal effects.
Development and testing of homogenisation methods: moving parameter experiments with ACMANT
Authors: Domonkos P. , Efthymiadis D.
Published: March 2013

Abstract. During the European project COST ES0601 (HOME) a new homogenisation method, ACMANT has been developed for the automatic homogenisation of monthly temperatures. ACMANT turned out to be one of the best performing methods during the blind test experiments of HOME. The methodological development of ACMANT has been continued since then, and nowadays ACMANT is likely the best homogenisation method for large and spatially dense temperature datasets. Ensemble moving parameter experiments have been done to obtain more information about the performance of ACMANT. The HOME Benchmark was used as test dataset, thus the results of the latest experiments with ACMANT are comparable with the performance of the other homogenisation methods participated in HOME. The results indicate that the performance of ACMANT is generally not sensitive to its parameterisation, i.e. the change of the performance is generally small for quite a wide range of each parameter. The presented methodology of moving parameter experiments provides results in a fast and easy to evaluate form.
Nitrous oxide emissions from crop rotations including wheat, oilseed rape and dry peas
Authors: Jeuffroy M. H. , Baranger E. , Carrouée B. , de Chezelles E. , Gosme M. , Hénault C. , Schneider A. , Cellier P.
Published: March 2013

Abstract. Approximately 65% of anthropogenic emissions of N2O, a potent greenhouse gas (GHG), originate from soils at a global scale, and particularly after N fertilisation of the main crops in Europe. Thanks to their capacity to fix atmospheric N2 through biological fixation, legumes can reduce N fertilizer use, and possibly N2O emissions. Nevertheless, the decomposition of crop organic matter during the crop cycle and residue decomposition, and possibly the N fixation process itself, could lead to N2O emissions. The objective of this study was to quantify N2O emissions from a dry pea crop (Pisum sativum, harvested at maturity) and from the subsequent crops in comparison with N2O emissions from wheat and oilseed rape crops, fertilized or not, in various rotations. A field experiment was conducted over 4 consecutive years to compare the emissions during the pea crop, in comparison with those during the wheat (fertilized or not) or oilseed rape crops, and after the pea crop, in comparison with other preceding crops. N2O fluxes were measured using static chambers. In spite of low N2O fluxes, mainly due to the site's soil characteristics, fluxes during the crop were significantly lower for pea and unfertilized wheat than for fertilized wheat and oilseed rape. The effect of the preceding crop was not significant, while soil mineral N at harvest was higher after the pea crop. These results should be confirmed over a wider range of soil types. Nevertheless, they demonstrate the absence of N2O emissions linked to the symbiotic N fixation process, and allow us to estimate the decrease in N2O emissions by 20–25% through including one pea crop in a three-year rotation. On a larger scale, this reduction of GHG emissions at field level has to be added to the decrease due to the reduced production and transport of the N fertilizer not applied to the pea crop.
The sensitivity of the energy budget and hydrological cycle to CO2 and solar forcing
Authors: Schaller N. , Cermak J. , Wild M. , Knutti R.
Published: March 2013

Abstract. The transient responses of the energy budget and the hydrological cycle to CO2 and solar forcings of the same magnitude in a global climate model are quantified in this study. Idealized simulations are designed to test the assumption that the responses to forcings are linearly additive, i.e. whether the response to individual forcings can be added to estimate the response to the combined forcing, and to understand the physical processes occurring as a response to a surface warming caused by CO2 or solar forcing increases of the same magnitude. For the global climate model considered, the responses of most variables of the energy budget and hydrological cycle, including surface temperature, do not add linearly. A separation of the response into a forcing and a feedback term shows that for precipitation, this non-linearity arises from the feedback term, i.e. from the non-linearity of the temperature response and the changes in the water cycle resulting from it. Further, changes in the energy budget show that less energy is available at the surface for global annual mean latent heat flux, and hence global annual mean precipitation, in simulations of transient CO2 concentration increase compared to simulations with an equivalent transient increase in the solar constant. On the other hand, lower tropospheric water vapor increases more in simulations with CO2 compared to solar forcing increase of the same magnitude. The response in precipitation is therefore more muted compared to the response in water vapor in CO2 forcing simulations, leading to a larger increase in residence time of water vapor in the atmosphere compared to solar forcing simulations. Finally, energy budget calculations show that poleward atmospheric energy transport increases more in solar forcing compared to equivalent CO2 forcing simulations, which is in line with the identified strong increase in large-scale precipitation in solar forcing scenarios.