bluuebunny/crossref_metadata_2025 huggingface dataset:
Reading the leaves: A comparison of leaf rank and automated areole measurement for quantifying aspects of leaf venation
Authors: Green Walton A. , Little Stefan A. , Price Charles A. , Wing Scott L. , Smith Selena Y. , Kotrc Benjamin , Doria Gabriela
Published: August 2014

The reticulate venation that is characteristic of a dicot leaf has excited interest from systematists for more than a century, and from physiological and developmental botanists for decades. The tools of digital image acquisition and computer image analysis, however, are only now approaching the sophistication needed to quantify aspects of the venation network found in real leaves quickly, easily, accurately, and reliably enough to produce biologically meaningful data. In this paper, we examine 120 leaves distributed across vascular plants (representing 118 genera and 80 families) using two approaches: a semiquantitative scoring system called “leaf ranking,” devised by the late Leo Hickey, and an automated image‐analysis protocol. In the process of comparing these approaches, we review some methodological issues that arise in trying to quantify a vein network, and discuss the strengths and weaknesses of automatic data collection and human pattern recognition. We conclude that subjective leaf rank provides a relatively consistent, semiquantitative measure of areole size among other variables; that modal areole size is generally consistent across large sections of a leaf lamina; and that both approaches—semiquantitative, subjective scoring; and fully quantitative, automated measurement—have appropriate places in the study of leaf venation.
Accuracy and consistency of grass pollen identification by human analysts using electron micrographs of surface ornamentation
Authors: Mander Luke , Baker Sarah J. , Belcher Claire M. , Haselhorst Derek S. , Rodriguez Jacklyn , Thorn Jessica L. , Tiwari Shivangi , Urrego Dunia H. , Wesseln Cassandra J. , Punyasena Surangi W.
Published: August 2014

• Premise of the study: Humans frequently identify pollen grains at a taxonomic rank above species. Grass pollen is a classic case of this situation, which has led to the development of computational methods for identifying grass pollen species. This paper aims to provide context for these computational methods by quantifying the accuracy and consistency of human identification.

• Methods: We measured the ability of nine human analysts to identify 12 species of grass pollen using scanning electron microscopy images. These are the same images that were used in computational identifications. We have measured the coverage, accuracy, and consistency of each analyst, and investigated their ability to recognize duplicate images.

• Results: Coverage ranged from 87.5% to 100%. Mean identification accuracy ranged from 46.67% to 87.5%. The identification consistency of each analyst ranged from 32.5% to 87.5%, and each of the nine analysts produced considerably different identification schemes. The proportion of duplicate image pairs that were missed ranged from 6.25% to 58.33%.

• Discussion: The identification errors made by each analyst, which result in a decline in accuracy and consistency, are likely related to psychological factors such as the limited capacity of human memory, fatigue and boredom, recency effects, and positivity bias.
A three-year review of antimicrobial resistance of Salmonella enterica serovars Typhi and Paratyphi A in Pakistan
Authors: Qamar Farah Naz , Azmatullah Asma , Kazi Abdul Momin , Khan Erum , Zaidi Anita Kaniz Mehdi
Published: August 2014

Introduction: Enteric fever is among the most common bacteraemic illnesses in South Asia. Multidrug resistance as well as fluoroquinolone resistance has severely limited therapeutic options in high disease burden countries such as Pakistan. This review was conducted to determine the frequency of drug-resistant Salmonella enterica serovar Typhi (S.Typhi) and Salmonella enterica serovar Paratyphi A (S. Paratyphi A) between2009 and 2011. Methodology: This study was a review of laboratory data. The antibiotic susceptibility of typhoidal Salmonellae isolated from blood cultures submitted to the Aga Khan University Hospital's laboratory from all over Pakistan between January 2009 and December 2011 were reviewed. Results: The sensitivity data of 4,323 positive isolates of S. Typhi and S. Paratyphi A isolated during the three-year period were reviewed. The majority of isolates were S. Typhi (59.6%).Over three years, the incidence of multidrug-resistant (MDR) S.Typhi remained high, ranging from 64.8%–66.0%, while MDR S. Paratyphi A decreased from 4.2% to 0.6%.Fluoroquinolone resistance increased for S. Typhi from 84.7% to 91.7%.Cefixime- and ceftriaxone-resistant S. Typhi were isolated in two children. Conclusions: Our results show high rates of multidrug and fluoroquinolone resistance among S. Typhi and S. Paratyphi. The occurrence of two cases of ceftriaxone resistance is alarming.
Prevalence of Trypanosoma cruzi infection in blood donors in El Salvador between 2001 and 2011
Authors: Sasagawa Emi , Guevara de Aguilar Ana Vilma , Hernández de Ramírez Marta Alicia , Romero Chévez José Eduardo , Nakagawa Jun , Cedillos Rafael Antonio , Misago Chizuru , Kita Kiyoshi
Published: August 2014

Introduction: El Salvador is regarded as a highly endemic country for Chagas disease, as evidenced by the relatively high estimated positive serology rate for Trypanosoma cruzi among blood donors. This study aimed to identify the factors contributing to this high rate by analyzing changes in T. cruzi seroprevalence. Methodology: Secondary data were collected from 31 blood banks operated by the Ministry of Health, the Red Cross, the Institute of Salvadoran Social Security, and the Military Hospital. The data were analyzed to determine the number of cases of T. cruzi seropositivity, and the average prevalence of seropositivity by province. Simple linear regression was performed to identify trends in T. cruzi seropositivity. Results: Analysis of the 885,187 blood samples collected between 2001 and 2011 revealed 21,693 cases of transfusion-related infections, with a significant reduction of T. cruzi seropositivity from 3.7% in 2001 to 1.7% in 2011, reflecting a 54% decrease over the course of a decade (R2 = 89.6%, p > 0.001). T. cruzi seroprevalence decreased in San Salvador, Santa Ana, Sonsonate, and Cuscatlán. In contrast, seroprevalence remained high with no decrease in Ahuachapán and San Vicente, and consistently low in the remainder of the country. Conclusions: Although the national prevalence of T. cruzi among blood donors has decreased, it remains high in the provinces of Ahuachapán and San Vicente. Strengthening vector control activities and developing an approach for the systematic follow-up of prospective blood donors with positive serology for T. cruzi are required, especially in areas with high seropositivity.
Hantavirus infection mimicking leptospirosis: how long are we going to rely on clinical suspicion?
Authors: Dahanayaka Niroshana Jathum , Agampodi Suneth Buddhika , Bandaranayaka Anoma Kumari , Priyankara Sumudu , Vinetz Joshep M
Published: August 2014

Hantavirus infections and leptospirosis can have similar clinical and epidemiological features. We present here a case study of a young farmer with fever during the post-flood leptospirosis outbreak in Anuradhapura, Sri Lanka, in 2011. He presented with a classical clinical picture of leptospirosis and was managed and notified as a case of leptospirosis. Retrospective analysis of a stored serum sample confirmed acute hantavirus infection. Diagnosis of newly identified or emerging infectious diseases such as hantavirus infection is challenging due to the lack of diagnostic facilities in developing countries. This case highlights the need for improving diagnostic facilities, educating medical staff, and conducting population-based prospective studies on hantavirus infections in Sri Lanka.
Low rifampicin concentrations in tuberculosis patients with HIV infection
Authors: Gengiah Tanuja Narayansamy , Botha Julia Hillary , Soowamber Deepak , Naidoo Kogieleum , Abdool Karim Salim S
Published: August 2014

Introduction: The efficacy of tuberculosis (TB) treatment in Human Immunodeficiency Syndrome (HIV) co-infected patients may be compromised by genetic and pharmacokinetic variation in drug disposition. Rifampicin is a critical component of TB treatment. We investigated the influence of drug transporter gene polymorphisms on rifampicin concentrations in TB-HIV co-infected patients in Durban, South Africa. Methodology: Rifampicin concentrations were measured 2.5 hours post-dose (approximated peak, C2.5hr) in patients receiving either 450mg or 600mg rifampicin, randomized to either integrated or sequential antiretroviral treatment. Patients were genotyped for SLCO1B1 (rs4149032) polymorphisms. A mixed effects regression model was fitted to assess the influence of various factors on rifampicin concentrations. TB recurrence rates were also estimated. Results: In 57 patients, median (IQR) C2.5hr was 3.6 (2.8-5.0) µg/mL. Polymorphism frequency in the SLCO1B1 (rs4149032) drug transporter gene was high (0.76) and was associated with low median rifampicin C2.5hr, 3.7 (2.8-5.0) µg/mL in the heterozygous and 3.4 (2.7-4.7) µg/mL in the homozygous variant carriers. Concentrations were also low in males (p < 0.0001) and those with low haemoglobin (p = 0.02). Although reinfection could not be distinguished from reactivation for the 43 patients followed post trial, the incidence of TB recurrence was 7.1 per 100 person-years. Of the eight patients in whom TB recurred, seven had the polymorphism. Conclusion: Approximated peak rifampicin concentrations were well below the recommended target range of 8 to 24 μg/mL in this patient population with its high frequency of the SLCO1B1 (rs4149032) polymorphism. Increased rifampicin dosage may be warranted in African, HIV- TB co-infected patients.
An overview of extended-spectrum beta-lactamases in veterinary medicine and their public health consequences
Authors: Nóbrega Diego Borin , Brocchi Marcelo
Published: August 2014

Serious human and animal infections caused by bacteria are usually treated with beta-lactams. Extended-spectrum beta-lactamases (ESBLs) constitute the most clinically and economically important enzymes that are able to hydrolyze and inactivate beta-lactam antibiotics in veterinary medicine. The spread of ESBLs represents a serious threat to healthcare systems, drastically undermining therapeutic options. The relationship between drug usage and the emergence of resistance has been extensively reported. Nevertheless, the use of antimicrobials in veterinary medicine and the emergence of ESBLs in animals remains a matter of debate. Moreover, there is still controversy about whether antibiotic usage in farm animals poses a potential public health risk. This review will (i) deal with  aspects related to the presence of ESBLs in veterinary medicine, (ii) its link with human medicine, and (iii) discuss strategies to be implemented to preserve antimicrobial effectiveness. New insights relative to old questions concerning antimicrobial use in domestic animals are also presented.
Higher levels of hepatitis C virus RNA found in blood donors co-infected with HIV as compared to HCV mono-infected donors
Authors: Alidjinou Enagnon Kazali , Moukassa Donatien , Ebatetou-Ataboho Eben , Mahoungou Gael Honal , Pambou Jean-Paul , Sané Famara , Prevost Brigitte , Bocket Laurence , Ibara Jean-Rosaire , Hober Didier
Published: August 2014

Introduction: Hepatitis C virus (HCV) infection and human immunodeficiency virus (HIV) infections are public health problems in sub-Saharan countries such as the Republic of Congo. HIV infection could impact the characteristics of HCV infection in co-infected people. We investigated HCV-HIV co-infection among blood donors in Congo. Methodology: Ninety-nine HIV-positive and/or HCV-seropositive blood donors were selected during screening and subsequently tested for aminotransferases and HCV RNA. Results: A total of 29 donors were found positive for HCV RNA (HCV-infected individuals), including 19/60 (31.66%) HIV donors (co-infected) and 10/39 (25.64%) non-HIV donors (mono-infected). Most of the co-infected donors (17/19) displayed a high viral load (> 5 log). The median HCV RNA level was at least 2 logs higher in co-infected people. The levels of alanine aminotransferase (ALT) were also slightly higher in co-infected donors than in HCV mono-infected donors. Conclusion: This study reports HCV-HIV co-infection among blood donors in Congo and shows that HCV viral load is higher in HIV donors.
First description of the worker caste of Nylanderia smythiesii (Hymenoptera: Formicidae)
Authors: Wachkoo Aijaz , Bharti Himender
Published: August 2014

The hitherto unknown worker caste of Nylanderia smythiesii (Forel, 1894) is described for the first time. Sexuals are redescribed and photomontage images of all castes are provided. A key is presented to separate the six Indian species of Nylanderia. Previously described Nylanderia assimilis (Jerdon, 1851) is considered a species inquirenda.
A stakeholder approach to international human rights. Could the trend become a tragedy ?
Authors: Matwijkiw Anja , Matwijkiw Bronik
Published: August 2014

Dans cet article, les deux auteurs présentent les divers postulats et implications de l’approche des parties prenantes au regard de la réglementation internationale des droits de l’homme. Alors que les Nations Unies ont déjà présenté la terminologie de « parties prenantes », l’organisation ne prend pas parti et ne se prononce donc pas, de manière expresse, sur le choix d’une approche lato sensu ou stricto sensu de la théorie des parties prenantes. Cependant, il est possible de démontrer qu’indirectement l’organisation est plus sensible au système que défendent les partisans de la conception large de la théorie des parties prenantes. Ceci est particulièrement vrai dans le cadre de l’analyse des droits fondamentaux qu’invoquent Herbert L.A. Hart et Neil MacCormick au moyen de leurs critères concurrentiels d’authentification auxquels s’ajoutent des composants variés du positivisme légal et de la doctrine du droit naturel. Dans la mesure où la théorie des parties prenantes a été conçue pour la gestion commerciale stratégique, il n’est prêté que peu d’attention aux aspects relevant de la philosophie du droit bien que, pour les Nations-Unies, ceux-ci soient fondamentaux. Les conclusions formulées suivent donc les implications des principaux postulats philosophiques et méthodologiques qui caractérisent chaque type d’approche. Dans le même temps, dans les contributions faites par les philosophes partisans de l’approche générale de la théorie des parties prenantes, la distinction opérée entre conceptions générale et étroite devient problématique. De ce fait, ceci est en pratique néfaste aux intérêts qui autrement auraient été protégés afin de garantir non seulement la liberté (v. droits civils/politiques) mais également le bien être (v. droits économiques et sociaux). En ouvrant la voie à l’attitude qui consiste à faire comme si de rien n’était, les Nations Unies devraient probablement y penser à deux fois - pour le bien de la mission même de l’organisation - et songer à l’idée d’une affiliation future à la théorie des parties prenantes.
La justification du pouvoir de sanction des AAI de régulation est-elle toujours pertinente ?
Authors: Achour M. Taibi
Published: August 2014

Pour justifier le pouvoir répressif des Autorités Administratives Indépendantes de Régulation (AAIR), les partisans de la régulation ont avancé les limites des pouvoirs classiques. Le pouvoir judiciaire est le premier visé par les critiques. En plus de la lourdeur de la procédure judiciaire, on a également reproché au juge son incapacité à maîtriser la technicité de la sphère économique. Cependant, avec la soumission de leurs décisions répressives à contrôle juridictionnel de pleine juridiction, conjugué au phénomène de juridictionnalisation qui a touché ces nouvelles autorités de régulation, il est tout à fait légitime de douter des arguments avancés.
La figure actuelle du juge en France et en Angleterre. L'attenuation des divergences originelles dans les attributions des juges français et anglais
Authors: Taleb Akila
Published: August 2014

Cet article a pour objet de déterminer la figure actuelle du juge au sein des systèmes de justice pénale français et anglais. L’étude qui consiste à présenter et à identifier, dans ses grandes lignes, les missions et rôles des juges français et anglais, insiste sur l’évolution de leurs fonctions respectives. A partir d’exemples précis, l’auteur met en exergue l’atténuation des divergences originelles - fondées sur la traditionnelle et désormais désuète dichotomie accusatoire/inquisitoire - en ce qui concerne les attributions des juges français et anglais.
Assisting Students in Finding Bugs and their Locations in Programming Solutions
Authors: Pham Long H. , Trinh Giang V. , Dinh Mai H. , Mai Nam P. , Quan Tho T. , Ngo Hung Q.
Published: August 2014

Teaching experience shows that programming is time consuming and can be acquired with substantial practice. Besides, students need to know whether their solutions are correct or incorrect and the root causes of their errors. Thus, teaching programming in a large class requires considerably many teaching assistants, which is costly. More importantly, a communication means that can support students virtually any time is also desirable. In order to handle these problems, a static method was applied to build an online intelligent tutoring system that can assist students checking their solutions. In addition, when detecting the errors, this system can suggest students to investigate the suspected code. This feature is really significant for students to self-practice and improve their learning.
Significance of Structural Dynamics in Engineering Education in the New Millennium
Authors: Thambiratnam David P.
Published: August 2014

Structural Dynamics has gained prominence recently due to (i) vibration problems in slender structures that have emerged as a result of new materials technology and aesthetic requirements, (ii) ageing bridge structures whose health needs to be monitored and appropriate retrofitting carried out to prevent failure and (iii) increased vulnerability of structures to seismic, impact and blast loads. Knowledge of structural dynamics is necessary to address these issues and their consequences. In recent times, structural dynamics research has generated considerable amount of new knowledge to address these issue, but this is not readily available to practicing engineers as very little or none of it enters the class rooms. This paper argues for the need to include structural dynamics and the new research knowledge into the syllabus of all civil engineering courses, especially those with a major in structural engineering. This will enable our future structural engineers to design and maintain safe and efficient structures.
Technology Adoption in Engineering Design for Distance Education
Authors: M.T.O. Amanullah , Chandran Jaideep , Stojcevski Alex
Published: August 2014

Technology plays a critical role in delivering modern education to the next generation. Proper and effective use of technology is extremely important especially for distance education. Students who enrol in distance mode have a number of limitations as most of them work full time along with the commitments to the family. Distance education in engineering has its own unique set of challenges; it has to ensure the learning outcomes are met through the content, delivery style and assessment strategies. It also has to ensure the distance students are provided a learning experience at par with on campus students in terms of access to laboratory facilities and hands on experience. The Project Oriented Design Based Learning model drives the learning through a design based project and employs a blended learning environment to address the challenges faced in distance engineering education. This paper discusses technology integration for the distance students based on the Project Oriented Design Based Learning.
Cross-Education Strength and Activation After Eccentric Exercise
Authors: Lepley Lindsey K. , Palmieri-Smith Riann M.
Published: August 2014

Context

After injury, eccentric exercise of the injured limb is often contraindicated. Cross-education training, whereby the uninvolved limb is exercised, is an alternative that may improve quadriceps muscle strength and activation in the unexercised limb.

Objective

To determine the effect of eccentric exercise on quadriceps strength and activation gains in the unexercised limb.

Patients or Other Participants

Eighteen healthy individuals were randomly assigned to an eccentric training group or a control group.

Intervention(s)

Quadriceps strength and activation measures were collected at preintervention, midintervention, and postintervention. Eccentric training participants exercised their dominant limb with a dynamometer in eccentric mode at 60°/s, 3 times per week for 8 weeks.

Main Outcome Measure(s)

Quadriceps strength was quantified at 30° and 60°/s in concentric and eccentric modes. Quadriceps activation was assessed using the burst superimposition technique and quantified via the central activation ratio. A 2 × 3 repeated-measures analysis of variance was used to detect the effects of group and testing session on quadriceps strength and activation. Where appropriate, post hoc Bonferroni multiple-comparisons procedures were used.

Results

We found greater eccentric strength in the unexercised limbs of eccentric training participants between preintervention and midintervention and between preintervention and postintervention (preintervention to midintervention: 30°/s P = .05; preintervention to postintervention: 30°/s P = .02, 60°/s P = .02). No differences were noted in concentric strength (P > .05). An overall trend toward greater quadriceps activation in the unexercised knee was detected between preintervention and postintervention (P = .063), with the eccentric training group demonstrating a strong effect (Cohen d = 0.83). Control strength did not change (P > .05).

Conclusions

Exercising with eccentric actions resulted in mode-specific and velocity-specific gains in quadriceps strength in the unexercised limb. A trend toward greater quadriceps activation in the unexercised knee was noted, suggesting that strength gains may have occurred because of enhanced neural activity. This type of therapy may be a useful addition to rehabilitation programs designed to improve quadriceps strength.
Myringoplasty with and without Cortical Mastoidectomy in Treatment of Non-cholesteatomatous Chronic Otitis Media: A Comparative Study
Authors: Tawab Hazem Mohammed Abdel , Gharib Fadi Mahmoud , Algarf Tareq M. , EISharkawy Louay S.
Published: August 2014

Objective

To compare the outcome and success of repair of uncomplicated tympanic membrane perforations with myringoplasty alone and when combined with mastoidectomy.

Methods

A prospective study where 40 patients with non-cholesteatomatous chronic suppurative otitis media (CSOM) were recruited during the period of June 2013 to December 2013 from the outpatient clinic of Otorhinolaryngology department, Faculty of medicine, Cairo University. Patients were managed medically and after dryness of their perforations they were operated upon. Twenty patients underwent simple myringoplasty alone and 20 patients underwent myringoplasty with cortical mastoidectomy. Underlay technique with temporalis fascia was done for all patients. Follow-up period was at least 3 months.

Results

Hearing improvement was comparable in both groups. There was no significant difference in graft uptake between the myringoplasty alone group (70%) and cortical mastoidectomy group (80%) ( P = 0.7). There was no significant difference in ear dryness between the myringoplasty alone group (75%) and cortical mastoidectomy group (90%) ( P = 0.4).

Conclusion

Mastoidectomy performed in non-cholesteatomatous CSOM in this study gives no statistically significant benefit over simple myringoplasty as regards graft success rate and dryness of the middle ear with comparable hearing outcome.
Neurological Toxicity in Metastatic Colorectal Cancer Patients Treated with Modified FOLFOX6 plus Bevacizumab
Authors: Otsu Satoshi , Hirashima Yoshinori , Nishikawa Kazuo , Sakashita Hiroyuki , Morinaga Ryotaro , Watanabe Koichiro , Shirao Kuniaki
Published: August 2014

This study was conducted to investigate the toxicity and efficacy of modified FOLFOX6 plus bevacizumab in patients with metastatic colorectal cancer with particular regard to oxaliplatin-induced neuropathy. Toxicity was graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) (version 3.0). The evaluation was especially focused on grade 2 oxaliplatin-induced neuropathy. The estimated median treatment time to occurrence of grade 2 sensory neuropathy was 7.3 months. The estimated median cumulative dose to occurrence of grade 2 sensory neuropathy was 931 mg/m2. This study clarified the treatment time from first dose as well as the cumulative dose of oxaliplatin leading to grade 2 neuropathy. It may be important to institute some clinical countermeasures when grade 2 neuropathy occurs so as to reduce the chance of progression to irreversible grade 3 neuropathy.
Chromosomal Rearrangement Features of Yersinia pestis Strains from Natural Plague Foci in China
Authors: Liang Ying , Xie Fang , Tang Xinyuan , Wang Mei , Zhang Enmin , Zhang Zhikai , Cai Hong , Wang Yanhua , Shen Xiaona , Zhao Hongqun , Yu Dongzheng , Xia Lianxu , Hai Rong
Published: August 2014

The Yersinia pestis chromosome contains a large variety and number of insert sequences that have resulted in frequent chromosome rearrangement events. To identify the chromosomal rearrangement features of Y. pestis strains from five typical plague foci in China and study spontaneous DNA rearrangements potentially stabilized in certain lineages of Y. pestis genomes, we examined the linking mode of locally collinear blocks (LCBs) in 30 Y. pestis strains by a polymerase chain reaction-based method. Our results suggest most strains have relatively stable chromosomal arrangement patterns, and these rearrangement characteristics also have a very close relationship with the geographical origin. In addition, some LCB linking modes are only present in specific strains. We conclude Y. pestis chromosome rearrangement patterns may reflect the genetic features of specific geographical areas and can be applied to distinguish Y. pestis isolates; furthermore, most of the rearrangement events are stable in certain lineages of Y. pestis genomes.
Ground-level ozone in four Chinese cities: precursors, regional transport and heterogeneous processes
Authors: Xue L. K. , Wang T. , Gao J. , Ding A. J. , Zhou X. H. , Blake D. R. , Wang X. F. , Saunders S. M. , Fan S. J. , Zuo H. C. , Zhang Q. Z. , Wang W. X.
Published: August 2014

Abstract. We analyzed measurements of ozone (O3) and its precursors made at rural/suburban sites downwind of four large Chinese cities – Beijing, Shanghai, Guangzhou and Lanzhou, to elucidate their pollution characteristics, regional transport, in situ production, and impacts of heterogeneous processes. The same measurement techniques and observation-based model were used to minimize uncertainties in comparison of the results due to difference in methodologies. All four cities suffered from serious O3 pollution but showed different precursor distributions. The model-calculated in situ O3 production rates were compared with the observed change rates to infer the relative contributions of on-site photochemistry and transport. At the rural site of Beijing, export of the well-processed urban plumes contributed to the extremely high O3 levels (up to an hourly value of 286 ppbv), while the O3 pollution observed at suburban sites of Shanghai, Guangzhou and Lanzhou was dominated by intense in-situ production. The O3 production was in a VOCs-limited regime in both Shanghai and Guangzhou, and a NOx-controlled regime in Lanzhou. The key VOC precursors are aromatics and alkenes in Shanghai, and aromatics in Guangzhou. The potential impacts on O3 production of several heterogeneous processes, namely, hydrolysis of dinitrogen pentoxide (N2O5), uptake of hydro peroxy radical (HO2) on particles and surface reactions of NO2 forming nitrous acid (HONO), were assessed. The analyses indicate the varying and considerable impacts of these processes in different areas of China depending on the atmospheric abundances of aerosol and NOx, and suggest the urgent need to better understand these processes and represent them in photochemical models.
Daily global fire radiative power fields estimation from one or two MODIS instruments
Authors: Remy S. , Kaiser J. W.
Published: August 2014

Abstract. Fires are important emitters of aerosol and trace gases and as such need to be taken into account in any atmospheric composition modeling enterprise. One method to estimate these emissions is to convert Fire Radiative Power (FRP) analysis to dry matter burnt and emissions of smoke constituents using land cover dependent conversion factors. Inventories like the Global Fire Assimilation System (GFAS) follow this approach by calculating daily global smoke emissions from FRP observed by the MODIS instruments on-board of the Terra and Aqua satellites. Observations with different overpass times systematically sample fires at different stages in the strong diurnal fire cycle. For some time periods, observations are available from only one instrument, which leads to a bias in the observed average FRP. We develop a method to correct this bias in daily FRP observations from any Low Earth Orbit (LEO) satellite, so that the budget of daily smoke emissions remains independent of the number of satellites from which FRP observations are taken into account. This ensures the possibility of running, e.g., GFAS in case of a default of one of the MODIS instruments. It also enables the extension GFAS to 2000–2002 and the inclusion of FRP observations from upcoming satellite missions. The correction combines linear and non-linear regressions and uses an adaptive regionalization algorithm. It removes the bias in daily average FRP observations from Terra and Aqua nearly entirely. Errors are larger for Terra than for Aqua, are generally relatively small at a global scale, but can be important at a local scale. The correction algorithm is applied to Terra observations from 25 February 2000 to 31 December 2002, when Aqua observations were not available. The database of fire emissions GFASv1.0 is extended correspondingly.
Chemical characterization of the main products formed through aqueous-phase photonitration of guaiacol
Authors: Kitanovski Z. , Čusak A. , Grgić I. , Claeys M.
Published: August 2014

Abstract. Guaiacol (2-methoxyphenol) and its derivatives can be emitted into the atmosphere by thermal degradation (i.e., burning) of wood lignins. Due to its volatility, guaiacol is predominantly distributed atmospherically in the gaseous phase. Recent studies have shown the importance of aqueous-phase reactions in addition to the dominant gas-phase and heterogeneous reactions of guaiacol, in the formation of secondary organic aerosol (SOA) in the atmosphere. The main objectives of the present study were to chemically characterize the main products of the aqueous-phase photonitration of guaiacol and examine their possible presence in urban atmospheric aerosols. The aqueous-phase reactions were carried out under simulated sunlight and in the presence of hydrogen peroxide and nitrite. The formed guaiacol reaction products were concentrated by solid-phase extraction and then purified with semi-preparative high-performance liquid chromatography (HPLC). The fractionated individual compounds were isolated as pure solids and further analyzed with liquid-state proton, carbon-13 and two-dimensional nuclear magnetic resonance (NMR) spectroscopy, and direct infusion negative ion electrospray ionization tandem mass spectrometry ((−)ESI-MS/MS). The NMR and product ion (MS2) spectra were used for unambiguous product structure elucidation. The main products of guaiacol photonitration are 4-nitroguaiacol (4NG), 6-nitroguaiacol (6NG), and 4,6-dinitroguaiacol (4,6DNG). Using the isolated compounds as standards, 4NG and 4,6DNG were unambiguously identified in winter PM10 aerosols from the city of Ljubljana (Slovenia) by means of HPLC/(−)ESI-MS/MS. Owing to the strong absorption of ultraviolet and visible light, 4,6DNG could be an important constituent of atmospheric "brown" carbon, especially in regions affected by biomass burning.
Automatic detection of ionospheric Alfvén resonances using signal and image processing techniques
Authors: Beggan C. D.
Published: August 2014

Abstract. Induction coils permit the measurement of small and very rapid changes of the magnetic field. A new set of induction coils in the UK (at L = 3.2) record magnetic field changes over an effective frequency range of 0.1–40 Hz, encompassing phenomena such as the Schumann resonances, magnetospheric pulsations and ionospheric Alfvén resonances (IARs). The IARs typically manifest themselves as a series of spectral resonance structures (SRSs) within the 1–10 Hz frequency range, usually appearing as fine bands or fringes in spectrogram plots and occurring almost daily during local night-time, disappearing during the daylight hours. The behaviour of the occurrence in frequency (f) and the difference in frequency between fringes (Δf) varies throughout the year. In order to quantify the daily, seasonal and annual changes of the SRSs, we developed a new method based on signal and image processing techniques to identify the fringes and to quantify the values of f, Δf and other relevant parameters in the data set. The technique is relatively robust to noise though requires tuning of threshold parameters. We analyse 18 months of induction coil data to demonstrate the utility of the method.
Silica cycling in the ultra-oligotrophic eastern Mediterranean Sea
Authors: Krom M. D. , Kress N. , Fanning K.
Published: August 2014

Abstract. Although silica is a key plant nutrient, there have been few studies aimed at understanding the Si cycle in the eastern Mediterranean Sea (EMS). Here we use a combination of new measurements and literature values to explain the silicic acid distribution across the basin and to calculate a silica budget to identify the key controlling processes. The surface water concentration of ∼1 μM, which is unchanging seasonally across the basin, was due to the inflow of western Mediterranean Sea (WMS) water at the Straits of Sicily. It does not change seasonally because there is only a sparse population of diatoms due to the low nutrient (N and P) supply to the photic zone in the EMS. The concentration of silicic acid in the deep water of the western Ionian Sea (6.3 μM) close to the S Adriatic are an of formation was due to the preformed silicic acid (3 μM) plus biogenic silica (BSi) from the dissolution of diatoms from the winter phytoplankton bloom (3.2 μM). The increase of 4.4 μM across the deep water of the EMS was due to silicic acid formed from in situ diagenetic weathering of aluminosilicate minerals fluxing out of the sediment. The major inputs to the EMS are silicic acid and BSi inflowing from the western Mediterranean (121 × 109 mol Si yr−1 silicic acid and 16 × 109 mol Si yr−1 BSi), silicic acid fluxing from the sediment (54 × 109 mol Si yr−1) and riverine (27 × 109 mol Si yr−1) and subterranean groundwater (9.7 × 109 mol Si yr−1) inputs, with only a minor direct input from dissolution of dust in the water column (1 × 109 mol Si yr−1). This budget shows the importance of rapidly dissolving BSi and in situ weathering of aluminosilicate minerals as sources of silica to balance the net export of silicic acid at the Straits of Sicily. Future measurements to improve the accuracy of this preliminary budget have been identified.
Upper ocean mixing controls the seasonality of planktonic foraminifer fluxes and associated strength of the carbonate pump in the oligotrophic North Atlantic
Authors: Salmon K. H. , Anand P. , Sexton P. F. , Conte M.
Published: August 2014

Abstract. Oligotrophic regions represent up to 75% of Earth's open-ocean environments, and are typically characterized by nutrient-limited upper-ocean mixed layers. They are thus areas of major importance in understanding the plankton community dynamics and biogeochemical fluxes. Here we present fluxes of total planktonic foraminifera and eleven planktonic foraminifer species from a bi-weekly sediment trap time series in the oligotrophic Sargasso Sea, subtropical western North Atlantic Ocean at 1500 m water depth, over two ∼2.5 year intervals, 1998–2000 and 2007–2010. Foraminifera flux was closely correlated with total mass flux and with carbonate and organic carbon fluxes. We show that the planktonic foraminifera flux increases approximately five-fold during the winter–spring, contributing up to ∼40% of the total carbonate flux, driven primarily by increased fluxes of deeper dwelling ("globorotaliid") species. Interannual variability in total foraminifera flux, and in particular fluxes of the deep dwelling Globorotalia truncatulinoides, Globorotalia hirsuta, Globorotalia inflata, were related to differences in seasonal mixed layer dynamics affecting the strength of the spring phytoplankton bloom and export flux, and by the passage of mesoscale eddies. The heavily calcified, dense carbonate tests of deeper dwelling species (3 times denser than surface dwellers) can contribute up to 90% of the foraminiferal-derived carbonate in this region during late winter-early spring, implying a high seasonality of the biological carbonate pump in oligotrophic oceanic regions. Our data suggest that climate cycles, such as the North Atlantic Oscillation, that modulate the depth of the mixed layer, intensity of nutrient upwelling and primary production could also modulate the strength of the biological carbonate pump in the oligotrophic North Atlantic.
Remote sensing algorithm for sea surface CO2 in the Baltic Sea
Authors: Parard G. , Charantonis A. A. , Rutgerson A.
Published: August 2014

Abstract. Studies of coastal seas in Europe have brought forth the high variability in the CO2 system. This high variability, generated by the complex mechanisms driving the CO2 fluxes makes their accurate estimation an arduous task. This is more pronounced in the Baltic Sea, where the mechanisms driving the fluxes have not been as highly detailed as in the open oceans. In adition, the joint availability of in-situ measurements of CO2 and of sea-surface satellite data is limited in the area. In this paper, a combination of two existing methods (Self-Organizing-Maps and Multiple Linear regression) is used to estimate ocean surface pCO2 in the Baltic Sea from remotely sensed surface temperature, chlorophyll, coloured dissolved organic matter, net primary production and mixed layer depth. The outputs of this research have an horizontal resolution of 4 km, and cover the period from 1998 to 2011. The reconstructed pCO2 values over the validation data set have a correlation of 0.93 with the in-situ measurements, and a root mean square error is of 38 μatm. The removal of any of the satellite parameters degraded this reconstruction of the CO2 flux, and we chose therefore to complete any missing data through statistical imputation. The CO2 maps produced by this method also provide a confidence level of the reconstruction at each grid point. The results obtained are encouraging given the sparsity of available data and we expect to be able to produce even more accurate reconstructions in the coming years, in view of the predicted acquisitions of new data.
A new Geoengineering Model Intercomparison Project (GeoMIP) experiment designed for climate and chemistry models
Authors: Tilmes S. , Mills M. J. , Niemeier U. , Schmidt H. , Robock A. , Kravitz B. , Lamarque J.-F. , Pitari G. , English J. M.
Published: August 2014

Abstract. A new Geoengineering Model Intercomparison Project (GeoMIP) experiment "G4 specified stratospheric aerosols" (short name: G4SSA) is proposed to investigate the impact of stratospheric aerosol geoengineering on atmospheric composition, climate, and the environment. In contrast to the earlier G4 GeoMIP experiment, which requires an emission of sulphur dioxide (SO2) into the model, a prescribed aerosol forcing file is provided to the community, to be consistently applied to future model experiments between 2020 and 2100. This stratospheric aerosol distribution, with a total burden of about 2 Tg S has been derived using the ECHAM5-HAM microphysical model, based on a continuous annual tropical emission of 8 Tg SO2 year−1. A ramp-up of geoengineering in 2020 and a ramp-down in 2070 over a period of two years are included in the distribution, while a background aerosol burden should be used for the last 3 decades of the experiment. The performance of this experiment using climate and chemistry models in a multi-model comparison framework will allow us to better understand the significance of the impact of geoengineering and the abrupt termination after 50 years on climate and composition of the atmosphere in a changing environment. The zonal and monthly mean stratospheric aerosol input dataset is available at https://www2.acd.ucar.edu/gcm/geomip-g4-specified-stratospheric-aerosol-data-set.
ORACLE: a module for the description of ORganic Aerosol Composition and Evolution in the atmosphere
Authors: Tsimpidi A. P. , Karydis V. A. , Pozzer A. , Pandis S. N. , Lelieveld J.
Published: August 2014

Abstract. A computationally efficient module for the description of organic aerosol (OA) partitioning and chemical aging has been developed and implemented into the EMAC atmospheric chemistry-climate model. The model simulates the formation of secondary organic aerosol (SOA) from semi-volatile (SVOCs), intermediate-volatility (IVOCs) and volatile organic compounds (VOCs). The model distinguishes SVOCs from biomass burning and all other combustion sources using two surrogate species for each source category with an effective saturation concentration at 298 K of C* = 0.1 and 10 μg m−3. Two additional surrogate species with C* = 103 and 105 μg m−3 are used for the IVOCs emitted by the above two source categories. Gas-phase photochemical reactions that change the volatility of the organics are taken into account. The oxidation products (SOA-sv, SOA-iv, and SOA-v) of each group of precursors (SVOCs, IVOCs, and VOCs) are simulated separately in the module to keep track of their origin. ORACLE efficiently describes the OA composition and evolution in the atmosphere and can be used to (i) estimate the relative contributions of SOA and primary organic aerosol (POA) to total OA, (ii) determine how SOA concentrations are affected by biogenic and anthropogenic emissions, and (iii) evaluate the effects of photochemical aging and long-range transport on the OA budget. Here we estimate that the predicted domain-average global surface OA concentration is 1.5 μg m−3 and consists of 7% POA from fuel combustion, 11% POA from biomass burning, 2% SOA-sv from fuel combustion, 3% SOA-sv from biomass burning, 15% SOA-iv from fuel combustion, 28% SOA-iv from biomass burning, 19% biogenic SOA-v, and 15% anthropogenic SOA-v. The tropospheric burden of OA components is predicted to be 0.23 Tg POA, 0.16 Tg SOA-sv, 1.41 Tg SOA-iv, and 1.2 Tg SOA-v.
Estimates of global dew collection potential
Authors: Vuollekoski H. , Vogt M. , Sinclair V. A. , Duplissy J. , Järvinen H. , Kyrö E.-M. , Makkonen R. , Petäjä T. , Prisle N. L. , Räisänen P. , Sipilä M. , Ylhäisi J. , Kulmala M.
Published: August 2014

Abstract. The global potential for collecting usable water from dew on an artificial collector sheet was investigated by utilising 34 years of meteorological reanalysis data as input to a dew formation model. Dew formation was found to be frequent and common, but daily yields were mostly below 0.1 mm. Nevertheless, some water-stressed areas such as the coastal regions of northern Africa and the Arabian Peninsula show potential for large-scale dew harvesting, as the yearly yield can reach up to 100 L m−2 for a commonly used polyethylene foil. Statistically significant trends were found in the data, indicating overall changes in dew yields between ±15% over the investigated time period.
A conceptual model of cyclical glacier flow in overdeepenings
Authors: Turrin J. B. , Forster R. R.
Published: August 2014

Abstract. A nearly four-decade, satellite-based velocity survey of the largest glaciers in the Alaska Range, Chugach Mountains, and the Wrangell Mountains of southern Alaska, spanning the early- to mid-1970s through the 2000s, reveals nine pulsing glaciers: Capps, Copper, Eldridge, Kahiltna, Matanuska, Nabesna, Nizina, Ruth, and Sanford glaciers. The pulses increase velocity by up to 2449% (Capps Glacier) or as little as 77% (Nabesna Glacier), with velocity increases for the other glaciers in the range of 100–250%. The pulses may last from between six years (Copper Glacier) to 12 years (Nizina Glacier) and consist of a multi-year acceleration phase followed by a multi-year deceleration phase during which significant portions of each glacier move en masse. The segments of each glacier affected by the pulses may be anywhere from 14 km (Sanford Glacier) to 36 km (Nabesna Glacier) in length and occur where the glaciers are either laterally constricted or joined by a major tributary, and the surface slopes at these locations are very shallow, 1–2°, suggesting the pulses occur where the glaciers are overdeepened. A conceptual model to explain the cyclical behavior of these pulsing glaciers is presented that incorporates the effects of glaciohydraulic supercooling, glacier dynamics, surface ablation, and subglacial sediment erosion, deposition, and deformation in overdeepenings.
Multi-Soliton and Rogue-Wave Solutions of the Higher-Order Hirota System for an Erbium-Doped Nonlinear Fiber
Authors: Zuo Da-Wei , Gao Yi-Tian , Sun Yu-Hao , Feng Yu-Jie , Xue Long
Published: August 2014

The nonlinear Schrödinger (NLS) equation appears in fluid mechanics, plasma physics, etc., while the Hirota equation, a higher-order NLS equation, has been introduced. In this paper, a higher-order Hirota system is investigated, which describes the wave propagation in an erbium-doped nonlinear fiber with higher-order dispersion. By virtue of the Darboux transformation and generalized Darboux transformation, multi-soliton solutions and higher-order rogue-wave solutions are derived, beyond the published first-order consideration.Wave propagation and interaction are analyzed: (i) Bell-shape solitons, bright- and dark-rogue waves are found; (ii) the two-soliton interaction is elastic, i. e., the amplitude and velocity of each soliton remain unchanged after the interaction; (iii) the coefficient in the system affects the direction of the soliton propagation, patterns of the soliton interaction, distance, and direction of the first-order rogue-wave propagation, as well as the range and direction of the second-order rogue-wave interaction.