bluuebunny/crossref_metadata_2025 huggingface dataset:
Realising a socially sustainable South African society through cooperative learning
Authors: Teise K LG
Published: June 2016

Education conceptualised in terms of the broader project of socially sustainable development (SSD) makes cooperative learning (CL) valuable in realising the former. Cooperative learning emphasises cooperation as integral to learner success, and because of this CL strategies have been found to be successful in fostering positive intergroup attitudes in classrooms, multicultural and otherwise. Social sustainable development concerns those aspects of human life and human relations which are necessary for the survival of society. Apart from it being particularly instrumental in improving learners’ academic performance, CL is equally valuable in promoting positive social relations amongst group members. Such relations are important for achieving social sustainable development. Therefore, CL could particularly be valuable to develop in learners, and the broader society, the social dispositions required for a socially sustainable South African society. My argument centres on the potential of CL as a practical strategy towards the development of a social sustainable South African society. In an attempt to demonstrate that CL holds the potential to contribute towards a social sustainable South African society, I’ll be focusing on the core tenets of SSD. These tenets are explored in relation to the principles and social outcomes of CL in order to establish the extent the latter could be instrumental in promoting SSD.
Understanding gender, sexuality and HIV risk in HEIs: narratives of international post-graduate students
Authors: Khau Mathabo , De Lange Naydene , Athiemoolam Logamurthie
Published: June 2016

Thirty years into the HIV&AIDS pandemic, the world is still striving to reduce new HIV infections and halve AIDS related deaths by 2015. However, sub-Saharan Africa still faces the burden of HIV infections as governments and private institutions try out different prevention strategies (UNAIDS 2011). Several scholars have argued that multiple concurrent sexual partnerships (MCSP) pose the greatest risk for new HIV infections. Furthermore, research has also linked MCSPs to mobility and migration. This paper draws from the project ‘Sexual identities and HIV&AIDS: an exploration of international university students’ experiences” which employed memory work, photo-voice, drawings and focus group discussions with ten (5male and 5female) Post Graduate international students at a South African university. Focussing on the data produced through memory work, I present university students’ lived-experience narratives of mobility and migration in relation to how they perceive MCSPs and HIV risk. The findings show how students construct their gendered and sexual identities in a foreign context and how these constructions intersect with their choices of sexual relationships and HIV risk. I argue from the findings that Higher Education Institutions should be treated as high risk ‘spaces of vulnerability’ and hence health support services and HIV intervention programming policies should be geared towards addressing such vulnerabilities in order to create sustainable teaching and learning environments that allow for all students to explore their full capabilities.
Sustainable rural learning ecologies- a prolegomenon traversing transcendence of discursive notions of sustainability, social justice, development and food sovereignty
Authors: Hlalele Dipane
Published: June 2016

This paper contributes, through traversing contested notions of sustainability, social justice, development and food sovereignty, to discourses around creation of sustainable rural learning ecologies. There has always been at least in the realm of scientific discourse, an attempt to dissociate the natural or physical environment from the social and human environment. This trend did not only affect the two spheres of existence only. It is further imbued and spawned fragmented and pervasive terminology, practices and human thought. Drawing from the ‘creating sustainable rural learning ecologies’ research project that commenced in 2011, I challenge and contest the use of such discourses and argue for the transcendence of such. This would, in my opinion, create space for harmonious and fluid co-existence between nature and humanity, such that the contribution of learning practices exudes and expedites sustainability in rural ecologies.
Imaging of common breast implants and implant-related complications: A pictorial essay
Authors: Shah Amisha T , Jankharia Bijal B
Published: June 2016

The number of women undergoing breast implant procedures is increasing exponentially. It is, therefore, imperative for a radiologist to be familiar with the normal and abnormal imaging appearances of common breast implants. Diagnostic imaging studies such as mammography, ultrasonography, and magnetic resonance imaging are used to evaluate implant integrity, detect abnormalities of the implant and its surrounding capsule, and detect breast conditions unrelated to implants. Magnetic resonance imaging of silicone breast implants, with its high sensitivity and specificity for detecting implant rupture, is the most reliable modality to asses implant integrity. Whichever imaging modality is used, the overall aim of imaging breast implants is to provide the pertinent information about implant integrity, detect implant failures, and to detect breast conditions unrelated to the implants, such as cancer.
Magnetic resonance imaging features of complications following hip replacement: A pictorial review
Authors: Pilania Khushboo , Jankharia Bhavin
Published: June 2016

Hip replacement surgery helps millions of people worldwide walk painlessly each year. With increasing life spans and decreased clinical threshold for surgery, this number will continue to rise. With the increase in the number of surgeries and the longevity of implants, the need for early and prompt diagnosis of complications is also rising. This essay underlines the fact that magnetic resonance imaging on a 1.5T scanner with specialized metal artefact reduction sequences is a viable technique to image the post-arthroplasty hip and has vast potential in the prompt and early diagnosis of complications in these patients.
Pulmonary arteriovenous malformation in chronic thromboembolic pulmonary hypertension
Authors: Sharma Arun , Gulati Gurpreet S , Parakh Neeraj , Aggarwal Abhinav
Published: June 2016

Chronic thromboembolic pulmonary hypertension is a morbid condition associated with complications such as hemoptysis, right heart failure, paradoxical embolism, and even death. There is no known association of chronic thromboembolic pulmonary hypertension with pulmonary arteriovenous malformation. Possible hypothesis for this association is an increased pulmonary vascular resistance leading to the compensatory formation of pulmonary arteriovenous malformation. We present one such case presenting with hemoptysis that was managed with endovascular treatment.
Characterization of lesions in dense breasts: Does tomosynthesis help?
Authors: Rangarajan Krithika , Hari Smriti , Thulkar Sanjay , Sharma Sanjay , Srivastava Anurag , Parshad Rajinder
Published: June 2016

Context: Mammography in dense breasts is challenging due to lesion obscuration by tissue overlap. Does tomosynthesis offers a solution? Aims: To study the impact of digital breast tomosynthesis (DBT) in characterizing lesions in breasts of different mammographic densities. Settings and Design: Prospective blinded study comparing mammography in two views with Mammography + Tomosynthesis. Methods and Material: Tomosynthesis was performed in 199 patients who were assigned Breast imaging reporting and data system (BIRADS) categories 0, 3, 4, or 5 on two-dimensional (2D) mammogram. Mammograms were first categorized into one of 4 mammographic breast densities in accordance with the American College of Radiology (ACR). Three radiologists independently analyzed these images and assigned a BIRADS category first based on 2D mammogram alone, and then assigned a fresh BIRADS category after taking mammography and tomosynthesis into consideration. A composite gold-standard was used in the study (histopathology, ultrasound, follow-up mammogram, magnetic resonance imaging). Each lesion was categorized into 3 groups—superior categorization with DBT, no change in BIRADS, or inferior BIRADS category based on comparison with the gold-standard. The percentage of lesions in each group was calculated for different breast densities. Results: There were 260 lesions (ages 28–85). Overall, superior categorization was seen in 21.2% of our readings on addition of DBT to mammography. DBT was most useful in ACR Densities 3 and 4 breasts where it led to more appropriate categorization in 27 and 42% of lesions, respectively. DBT also increased diagnostic confidence in 54.5 and 63.6% of lesions in ACR Densities 3 and 4, respectively. Conclusions: In a diagnostic setting, the utility of tomosynthesis increases with increasing breast density. This helps in identifying the sub category of patients where DBT can actually change management.
Spontaneous external auditory canal cholesteatoma in a young male: Imaging findings and differential diagnoses
Authors: Aswani Yashant , Varma Ravi , Achuthan Gayathri
Published: June 2016

A cholesteatoma is a non-neoplastic lesion of the petrous temporal bone commonly described as “skin in the wrong place.” It typically arises within the middle ear cavity, may drain externally via tympanic membrane (mural type), or may originate in the external auditory canal (EAC). The latter type is rarely encountered and typically affects the elderly. EAC cholesteatoma poses diagnostic challenges because it has numerous differential diagnoses. The present case describes a 19-year-old male who presented with gradually progressive diminution of hearing in a previously naïve right ear since 8 months. A soft tissue attenuation lesion confined to the right EAC with erosion of the canal on computed tomography prompted magnetic resonance imaging (MRI). The lesion showed restricted diffusion on MRI. Thus, a diagnosis of spontaneous EAC cholesteatoma was established. The case elucidates the rarity of spontaneous EAC cholesteatoma in a young male. In addition, it describes the role of imaging to detect, delineate the extent, and characterize lesions of petrous temporal bone. The case also discusses common differential diagnoses of EAC cholesteatoma, as well as the importance of diffusion weighted imaging in EAC cholesteatoma similar to its middle ear counterpart.
Amplatzer vascular plug as an embolic agent in different vascular pathologies: A pictorial essay
Authors: Tresley Jonathan , Bhatia Shivank , Kably Issam , Poozhikunnath Mohan Prasoon , Salsamendi Jason , Narayanan Govindarajan
Published: June 2016

The Amplatzer Vascular Plug (AVP) is a cylindrical plug made of self-expanding nitinol wire mesh with precise delivery control, which can be used for a variety of vascular pathologies. An AVP is an ideal vascular occlusion device particularly in high-flow vessels, where there is high risk of migration and systemic embolization with traditional occlusion devices. We performed 28 embolizations using the AVP from 2009 to 2014 and achieved complete occlusion without complications.
Bilateral nasolabial cysts - case report and review of literature
Authors: Patil Aruna R , Singh Abhinav Pratap , Nandikoor Shrivalli , Meganathan Prabhu
Published: June 2016

Nasolabial cyst is a non-odontogenic, extraosseous, soft tissue cyst, commonly unilateral, located in the nasolabial fold. Bilateral nasolabial cysts are of rare occurrence. This case report describes the multimodality imaging appearance of bilateral nasolabial cysts with a review of literature.
Percutaneous repair of iatrogenic subclavian artery injury by suture-mediated closure device
Authors: Chivate Rahul S , Kulkarni Suyash S , Shetty Nitin S , Polnaya Ashwin M , Gala Kunal B , Patel Paresh G
Published: June 2016

Central venous catheterization through internal jugular vein is done routinely in intensive care units. It is generally safe, more so when the procedure is performed under ultrasound guidance. However, there could be inadvertent puncture of other vessels in the neck when the procedure is not performed under real-time sonographic guidance. Closure of this vessel opening can pose a challenge if it is an artery, in a location difficult to compress, and is further complicated by deranged coagulation profile. Here, we discuss the removal of an inadvertently placed catheter from subclavian artery with closure of arteriotomy percutaneously using arterial suture-mediated closure device.
Stability for the Brunn-Minkowski and Riesz Rearrangement Inequalities, with Applications to Gaussian Concentration and Finite Range Non-local Isoperimetry
Authors: Carlen Eric , Maggi Francesco
Published: June 2016

We provide a simple, general argument to obtain improvements of concentration-type inequalities starting from improvements of their corresponding isoperimetric-type inequalities. We apply this argument to obtain robust improvements of the Brunn-Minkowski inequality (for Minkowski sums between generic sets and convex sets) and of the Gaussian concentration inequality. The former inequality is then used to obtain a robust improvement of the Riesz rearrangement inequality under certain natural conditions. These conditions are compatible with the applications to a finite-range nonlocal isoperimetric problem arising in statistical mechanics
Null structure and local well-posedness in the energy class for the Yang–Mills equations in Lorenz gauge
Authors: Selberg Sigmund , Tesfahun Achenef
Published: June 2016

We demonstrate null structure in the Yang–Mills equations in Lorenz gauge. Such structure was found in Coulomb gauge by Klainerman and Machedon, who used it to prove global wellposedness for finite-energy data in the temporal gauge by passing to local Coulomb gauges via Uhlenbeck’s Lemma. Compared with the Coulomb gauge, the Lorenz gauge has the advantage – shared with the temporal gauge – that it can be imposed globally in space even for large solutions. Using the null structure and bilinear space-time estimates, we also prove local-in-time wellposedness of the Yang–Mills equations in Lorenz gauge for data with finite energy, with a time of existence depending on the initial energy and on the

H^s \times H^{s–1}

-norm of the initial gauge potential, for some choice of

s < 1

sufficiently close to 1.
Stable lattices and the diagonal group
Authors: Shapira Uri , Weiss Barak
Published: June 2016

Inspired by work of McMullen, we show that any orbit of the diagonal group in the space of lattices accumulates on the set of stable lattices. As consequences, we settle a conjecture of Ramharter concerning the asymptotic behavior of the Mordell constant, and reduce Minkowski’s conjecture on products of linear forms to a geometric question, yielding two new proofs of the conjecture in dimensions up to 7.
Rational Pontryagin classes and functor calculus
Authors: Reis Rui , Weiss Michael S.
Published: June 2016

It is known that in the integral cohomology of

B \mathrm {SO}(2m)

, the square of the Euler class is the same as the Pontryagin class in degree

4m

. Given that the Pontryagin classes extend
rationally
to the cohomology of

B

STOP(

2m

), it is reasonable to ask whether the same relation between the Euler class and the Pontryagin class in degree

4m

is still valid in the rational cohomology of

B

STOP(

2m

). In this paper we reformulate the hypothesis as a statement in differential topology, and also in a functor calculus setting.
Ricci flow on quasiprojective manifolds II
Authors: Lott John , Zhang Zhou
Published: June 2016

We study the Ricci flow on complete Kähler metrics that live on the complement of a divisor in a compact complex manifold. In earlier work, we considered finite-volume metrics which, at spatial infinity, are transversely hyperbolic. In the present paper we consider three different types of spatial asymptotics: cylindrical, bulging and conical. We show that in each case, the asymptotics are preserved by the Kähler–Ricci flow.We address long-time existence, parabolic blowdown limits and the role of the Kähler–Ricci flow on the divisor.
Construction and Analysis of an Adapted Spectral Finite Element Method to Convective Acoustic Equations
Authors: Hüppe Andreas , Cohen Gary , Imperiale Sébastien , Kaltenbacher Manfred
Published: June 2016

The paper addresses the construction of a non spurious mixed spectral finite element (FE) method to problems in the field of computational aeroacoustics. Based on a computational scheme for the conservation equations of linear acoustics, the extension towards convected wave propagation is investigated. In aeroacoustic applications, the mean flow effects can have a significant impact on the generated sound field even for smaller Mach numbers. For those convective terms, the initial spectral FE discretization leads to non-physical, spurious solutions. Therefore, a regularization procedure is proposed and qualitatively investigated by means of discrete eigenvalues analysis of the discrete operator in space. A study of convergence and an application of the proposed scheme to simulate the flow induced sound generation in the process of human phonation underlines stability and validity.
Об уточнении дисперсионных оценок для одномерных уравнений Шрeдингера
и Клейна-Гордона
Authors: Egorova Irina Evgen'evna , Kopylova Elena Andreevna , Marchenko Vladimir Alexandrovich , Teschl Gerald
Published: June 2016

Доказывается, что для одномерного оператора Шрeдингера с потенциалом, имеющим первый интегрируемый момент, элементы матрицы рассеяния принадлежат унитальной винеровской алгебре функций с интегрируемыми преобразованиями Фурье. С использованием этого факта выводятся новые дисперсионные оценки для решений соответствующих уравнений Шрeдингера и Клейна-Гордона. В частности, мы избавляемся от условия более сильного убывания потенциала в случае наличия резонанса в конце непрерывного спектра.
Библиография: 29 названий.
Новые подходы к обратным задачам рассеяния
Authors: Palamodov Viktor Pavlovich
Published: June 2016

Приводится обзор известных и новых математических методов, дающих точные аналитические результаты в задачах восстановления среды по данным рассеяния.
Библиография: 42 названия.
Mamma Mia, A Singable Translation!
Authors: Stopar Andrej
Published: June 2016

The article discusses and analyzes approaches to translating singable texts. It presents a linguistic (prosodic, lexical and structural) analysis of the Slovenian translation of the musical Mamma Mia! The aim of the qualitative and quantitative study is to investigate the translation strategies used to produce a singable target text. The results of the analysis suggest that producing a prosodic match is a basic requirement, whereas the lexical, structural and/or poetic characteristics of the source text are subject to changes. Overall, the findings show that the function and the purpose of the translation play a crucial role in the prioritization of translation strategies.
Songs as Elements in the Generic Structure of Film Musicals
Authors: Plemenitaš Katja
Published: June 2016

The paper focuses on the description of film musicals as a subgenre of the genre family of musicals. Their dramatic structure is examined in terms of the generic elements that constitute the progression of a story expressed through the combination of spoken dialogue, songs and dance. The function of songs in the generic structure of film musicals is examined in the framework of the systemic-functional theory of register and genre. Special attention is given to the role of songs in the unfolding of the narrative. The theoretical observations about the role of songs in the register and genre of film musicals are then illustrated with an analysis of the use of songs in the TV musical High School Musical 2.
The Ironic Musical Edge: Using Songs to Present and Question Myths
Authors: Blake Jason
Published: June 2016

Professors never have enough time to cover everything they would like to teach. If the temptation in literature survey courses is to whittle the reading list down to a few canonical texts, the temptation in culture courses is to reduce “American Culture” or “Canadian Culture” to facts and figures, important dates in history, and so on. This paper argues that ironic songs can efficiently introduce important information about a country’s myths and sense of self, while simultaneously questioning those myths. After a discussion of syllabus agonies of choice, the paper discusses irony, then irony in music, before finishing with an examination of The Arrogant Worm’s comic song “Canada’s Really Big.”
The widening gap of gender inequality in Nigerian politics: Advocating a quota system approach
Authors: Okorie Martha
Published: June 2016

In Nigeria, only 25 out of 360 members of the Nigerian House of Representative are women and following the 2015 general elections, that number reduced to 17 out of 360. This is undoubtedly a consequence of gender inequality in the pursuit of political opportunities in Nigeria. A number of scholars have suggested that structural problems like the patriarchy and restricted economic opportunities for women is mainly responsible for their unequal representation in the country’s politics. In fact, Nigeria has one of the lowest rates of female entrepreneurship in sub-Saharan Africa. This situation, coupled with their socio-culturally ascribed roles as being restricted to motherhood or wife only serves to deepen their exclusion. Advocates on gender equality in Nigeria have noted that a viable means of reducing the gender gap would be the use of affirmative action which provides an institutional and legal framework for marginalized groups of the society to have equal representation. The counter-argument so far has been that the constitution of Nigeria does not prevent any gender from aspiring to electoral position, but prevailing evidence has shown that this is not  enough. This research paper therefore argues that for Nigeria to breach the gender inequality gap, it has to introduce quota system just like in federal appointments and in the educational sector to improve female representation in politics and by extension women voices within the political discourse.Keywords: Gender inequality, Nigerian politics, Quota system approach
Corruption in the Civil Service: The dearth of effective service delivery
Authors: Eke Gabriel Favour
Published: June 2016

The paper discussed the origin of the Nigerian Civil Service and the consequences of corruption that has crippled the service in the recent times. The paper was of the opinion that today’s Civil Service in Nigeria is a carryover of the British imperialist administrative structure. The paper stated that the reasons for the corrupt civil service which in turn has given room to ineffective service delivery are the weak institutional structures, cumbersome administrative procedure, negative attitude of the civil servants to work and individuals’ insatiable appetite for wealth at all cost. The paper discovered that the culture of accountability and ethical behaviour which the service was known for has been thrown overboard. Finally, the paper concluded by suggesting ways forward which include bridging the gap in the remuneration of public and civil servants, enabling civil servants benefit in the monetization process, proper and constant reforms, training of the civil servants on civil service rules and holding culpable corrupt civil servants.Keyword: Corruption, Lack of accountability, Poor service delivery and cumbersome administrative procedure in the civil service
Challenges of Nigeria’s foreign policy
Authors: Enuka Chuka , Ojukwu Emmanuel C.
Published: June 2016

Nigeria’s foreign policy like those of every other elsewhere, is hoped to achieve for the benefit of Nigeria and Nigerians, the aspired goals and articulated interests of the Nigerian state. This expectation, by the judgment of many informed Nigerians, is yet to be fully realized. Nigeria’s foreign policy inter alia, has failed to work out the transformation of Nigeria’s status and Nigerians’ lives from where it is, to where it should be. What possibly could answer for this foreign policy failure? In response to the puzzle, this paper excurses into the mixed and myriad challenges that have vexed Nigeria’s foreign policy from the formative years of her foreign policy formulation and implementation to the present. The finding is that the persistence of these challenges due to neglect, bad and irresponsible leadership is debilitating to Nigeria’s foreign policy output and has made foreign policy performance leave much to be desired. The paper concludes with a number of recommended suggestions as a panacea to the identified teething challenges.
Sexual predators or preys: Inter-racial sexual relationships in Jude Dibia’s novels
Authors: Okolo Ifeyinwa Genevieve
Published: June 2016

Traditional gender role assignment perceives sexual predation as specifically male with the female as the prey while colonial studies usually interpret the West as predatory with Africa as its prey. Using the psychoanalytical concept of “othering”, this paper studies inter-racial sexual relations/relationships in Jude Dibia’s novels – Unbridled, Walking with Shadows, and Blackbird – to show that the role of prey or predator is not domiciled with any gender or race but in the individual. The definition of prey/predator is greatly influenced by immediate environment. Both men and women could be sexual preys and/or predators given their socioeconomic standing, socio-cultural and religious positioning or beliefs/practices. Dibia in his novels shows how sexual behaviours, identities, and perceptions are defined and redefined depending on where the centre or margin is located at the point of definition.Keywords: sexual predation, race, othering, and masculinity
Relevance and commitment in Ezenwa-Ohaeto’s pidgin poetry collections
Authors: Ezeji Ogechi Blessing
Published: June 2016

The question of relevance and commitment is a recurring one in African literature written in Standard English. This paper seeks to ask the same question with regards to poetry in Pidgin English. The question then becomes- is the poet who writes in pidgin English as committed to the social course of his society as his counterpart who writes in Standard English? If the above question is answered in the affirmative, a follow up question will be: Is there any relationship between his form, in this case, Pidgin English and the content of the message? If this question is also answered in the affirmative, the next question will be:- to what extent do form and content intertwine to give the reader a completely rewarding poetic experience. These questions are answered through the review of Ezenwa-Ohaeto’s pidgin poetry collections. The paper makes use of the Marxist critical theory.
Climatological and radiative properties of midlatitude cirrus clouds derived by automatic evaluation of lidar measurements
Authors: Kienast-Sjögren Erika , Rolf Christian , Seifert Patric , Krieger Ulrich K. , Luo Bei P. , Krämer Martina , Peter Thomas
Published: June 2016

Abstract. Cirrus, i.e., high, thin clouds that are fully glaciated, play an important role in the Earth's radiation budget as they interact with both long- and shortwave radiation and affect the water vapor budget of the upper troposphere and stratosphere. Here, we present a climatology of midlatitude cirrus clouds measured with the same type of ground-based lidar at three midlatitude research stations: at the Swiss high alpine Jungfraujoch station (3580 m a.s.l.), in Zürich (Switzerland, 510 m a.s.l.), and in Jülich (Germany, 100 m a.s.l.). The analysis is based on 13 000 h of measurements from 2010 to 2014. To automatically evaluate this extensive data set, we have developed the Fast LIdar Cirrus Algorithm (FLICA), which combines a pixel-based cloud-detection scheme with the classic lidar evaluation techniques. We find mean cirrus optical depths of 0.12 on Jungfraujoch and of 0.14 and 0.17 in Zürich and Jülich, respectively. Above Jungfraujoch, subvisible cirrus clouds (τ < 0.03) have been observed during 6 % of the observation time, whereas above Zürich and Jülich fewer clouds of that type were observed. Cirrus have been observed up to altitudes of 14.4 km a.s.l. above Jungfraujoch, whereas they have only been observed to about 1 km lower at the other stations. These features highlight the advantage of the high-altitude station Jungfraujoch, which is often in the free troposphere above the polluted boundary layer, thus enabling lidar measurements of thinner and higher clouds. In addition, the measurements suggest a change in cloud morphology at Jungfraujoch above ∼ 13 km, possibly because high particle number densities form in the observed cirrus clouds, when many ice crystals nucleate in the high supersaturations following rapid uplifts in lee waves above mountainous terrain. The retrieved optical properties are used as input for a radiative transfer model to estimate the net cloud radiative forcing, CRFNET, for the analyzed cirrus clouds. All cirrus detected here have a positive CRFNET. This confirms that these thin, high cirrus have a warming effect on the Earth's climate, whereas cooling clouds typically have cloud edges too low in altitude to satisfy the FLICA criterion of temperatures below −38 °C. We find CRFNET = 0.9 W m−2 for Jungfraujoch and 1.0 W m−2 (1.7 W m−2) for Zürich (Jülich). Further, we calculate that subvisible cirrus (τ < 0.03) contribute about 5 %, thin cirrus (0.03 < τ < 0.3) about 45 %, and opaque cirrus (0.3 < τ) about 50 % of the total cirrus radiative forcing.
Mercury emissions of a coal fired power plant in Germany
Authors: Weigelt Andreas , Slemr Franz , Ebinghaus Ralf , Pirrone Nicola , Bieser Johannes , Bödewadt Jan , Esposito Giulio , van Velthoven Peter F. J.
Published: June 2016

Abstract. Hg/SO2, Hg/CO, NOx/SO2 emission ratios (ERs) in the plume of coal fired power plant (CFPP) Lippendorf near Leipzig in Germany were determined within the European Tropospheric Mercury Experiment (ETMEP) aircraft campaign in August 2013. GOM fraction of mercury emissions was also assessed. Measured Hg/SO2 and Hg/CO ERs were within the measurement uncertainties consistent with the ratios calculated from annual emissions in 2013 reported by the CFPP operator, the NOx/SO2 ER was somewhat lower. GOM fraction of total mercury emissions, estimated by three independent methods, was ~10 % with an upper limit of ~25 %. This result is consistent with findings by others and suggests that GOM fractions of ~40 % of CFPP mercury emissions in current emission inventories are overestimated.
Non-stomatal exchange in ammonia dry deposition models: Comparison of two state-of-the-art approaches
Authors: Schrader Frederik , Brümmer Christian , Flechard Chris R. , Wichink Kruit Roy J. , van Zanten Margreet C. , Richter Undine , Hensen Arjan , Erisman Jan Willem
Published: June 2016

Abstract. The accurate representation of bidirectional ammonia (NH3) biosphere-atmosphere exchange is an important part of modern air quality models. However, the cuticular (or external leaf surface) pathway, as well as other non-stomatal ecosystem surfaces, still pose a major challenge of translating our knowledge into models. Dynamic mechanistic models including complex leaf surface chemistry have been able to accurately reproduce measured bidirectional fluxes in the past, but their computational expense and challenging implementation into existing air quality models call for steady-state simplifications. We here qualitatively compare two semi-empirical state-of-the-art parameterizations of a unidirectional non-stomatal resistance (Rw) model after Massad et al. (2010), and a quasi-bidirectional non-stomatal compensation point (χw) model after Wichink Kruit et al. (2010), with NH3 flux measurements from five European sites. In addition, we tested the feasibility of using backward-looking moving averages of air NH3 concentrations as a proxy for prior NH3 uptake and driver of an alternative parameterization of non-stomatal emission potentials (Γw) for bidirectional non-stomatal exchange models. Results indicate that the Rw-only model has a tendency to underestimate fluxes, while the χw model mainly overestimates fluxes, although systematic underestimations can occur under certain conditions, depending on temperature and ambient NH3 concentrations at the site. The proposed Γw parameterization appears to have potential for improvement, but cannot be recommended for use in large scale simulations in its present state due to large uncertainties. As an interim solution for improving flux predictions, we recommend to reduce the minimum allowed Rw and the temperature response parameter in the unidirectional model and to revisit the temperature dependent Γw parameterization of the bidirectional model.
Can simple models predict large scale surface ocean isoprene concentrations?
Authors: Booge Dennis , Marandino Christa A. , Schlundt Cathleen , Palmer Paul I. , Schlundt Michael , Atlas Elliot L. , Bracher Astrid , Saltzman Eric S. , Wallace Douglas W. R.
Published: June 2016

Abstract. We use isoprene and related field measurements from three different ocean data sets together with remotely sensed satellite data to model global marine isoprene emissions. We show that using monthly mean satellite derived chl-a concentrations to parameterize isoprene with a constant chl-a normalized isoprene production rate underpredicts the measured oceanic isoprene concentration by a mean factor of 19 ± 12. Improving the model by using phytoplankton functional type dependent production values and by decreasing the bacterial degradation rate of isoprene in the water column results in only a slight underestimation (factor 1.7 ± 1.2). We calculate global isoprene emissions of 0.21 Tg C for 2014 using this improved model, which is twice the value calculated using the original model. Nonetheless, the sea-to-air fluxes have to be at least one order of magnitude higher to account for measured atmospheric isoprene mixing ratios. These findings suggest that there is at least one missing oceanic source of isoprene influencing the atmospheric concentrations and, therefore, effecting the importance of marine derived isoprene as a precursor to remote marine boundary layer particle formation.
Comparison of OMI NO2 observations and their seasonal and weekly cycles with ground-based measurements in Helsinki
Authors: Ialongo Iolanda , Herman Jay , Krotkov Nick , Lamsal Lok , Boersma Folkert , Hovila Jari , Tamminen Johanna
Published: June 2016

Abstract. We present the comparison of satellite-based OMI (Ozone Monitoring Instrument) NO2 products with ground-based observations in Helsinki. OMI NO2 total columns, available from standard product (SP) and DOMINO algorithm, are compared with the measurements performed by the Pandora spectrometer in Helsinki in 2012. The relative difference between Pandora #21 and OMI SP retrievals is 4 % and −6 % for clear sky and all sky conditions, respectively. DOMINO NO2 retrievals showed slightly lower total columns with median differences about −5 % and −14 % for clear sky and all sky conditions, respectively. Large differences often correspond to cloudy autumn-winter days with solar zenith angles above 65°. Nevertheless, the differences remain within the retrieval uncertainties. Furthermore, the weekly and seasonal cycles from OMI, Pandora and NO2 surface concentrations are compared. Both satellite- and ground-based data show a similar weekly cycle, with lower NO2 levels during the weekend compared to the weekdays as result of reduced emissions from traffic and industrial activities. Also the seasonal cycle shows a similar behaviour, even though the results are affected by the fact that most of the data are available during spring-summer because of cloud cover in other seasons. This is one of few works in which OMI NO2 retrievals are evaluated in a urban site at high latitudes (60° N). Despite the city of Helsinki having relatively small pollution sources, OMI retrievals have proved to be able to describe air quality features and variability similar to surface observations. This adds confidence in using satellite observations for air quality monitoring also at high latitudes.
Blooms of cyanobacteria in a temperate Australian lagoon system post and prior to European settlement
Authors: Cook Perran L. M. , Jennings Miles , Holland Daryl P. , Beardall John , Briles Christy , Zawadzki Atun , Doan Phuong , Mills Keely , Gell Peter
Published: June 2016

Abstract. Blooms of noxious N2 fixing cyanobacteria such as Nodularia spumigena are a recurring problem in some estuaries; however, the historic occurrence of such blooms in unclear in many cases. Here we report the results of a palaeoecological study on a temperate Australian lagoon system (the Gippsland Lakes) where we used stable isotopes and pigment biomarkers in dated cores as proxies for eutrophication and blooms of cyanobacteria. Pigment proxies show a clear signal, with an increase in cyanobacterial pigments (echinenone, canthaxanthin and zeaxanthin) in the period coinciding with recent blooms. Another excursion in these proxies was observed prior to the opening of an artificial entrance to the lakes in 1889, which markedly increased the salinity of the Gippsland Lakes. A coincident increase in the sediment organic-carbon content in the period prior to the opening of the artificial entrance suggests that the bottom waters of the lakes were more stratified and hypoxic, which would have led to an increase in the recycling of phosphorus. After the opening of the artificial entrance, there was a  ∼  60-year period with low values for the cyanobacterial proxies as well as a low sediment organic-carbon content suggesting a period of low bloom activity associated with the increased salinity of the lakes. During the 1940s, the current period of re-eutrophication commenced, as indicated by a steadily increasing sediment organic-carbon content and cyanobacterial pigments. We suggest that increasing nitrogen inputs from the catchment led to the return of hypoxia and increased phosphorus release from the sediment, which drove the re-emergence of cyanobacterial blooms.
A novel permanent gauge-cam station for surface-flow observations on the Tiber River
Authors: Tauro Flavia , Petroselli Andrea , Porfiri Maurizio , Giandomenico Lorenzo , Bernardi Guido , Mele Francesco , Spina Domenico , Grimaldi Salvatore
Published: June 2016

Abstract. Flow monitoring of riverine environments is crucial for hydrology and hydraulic engineering practice. Besides few experimental implementations, flow gauging relies on local water level and surface-flow velocity measurements through ultrasonic meters and radars. In this paper, we describe a novel permanent gauge-cam station for large-scale and continuous observation of surface flows, based on remote acquisition and calibration of video data. Located on the Tiber River, in the center of Rome, Italy, the station captures 1 min videos every 10 min over an area oriented along the river cross section of up to 20.6  ×  15.5 m2. In a feasibility study, we demonstrate that accurate surface-flow velocity estimations can be obtained by analyzing experimental images via particle tracking velocimetry (PTV). In medium illumination conditions (70–75 lux), PTV leads to velocity estimations in close agreement with radar records and is less affected by uneven lighting than large-scale particle image velocimetry. Future efforts will be devoted to the development of a comprehensive test bed infrastructure for investigating the potential of multiple optics-based approaches for surface hydrology.
Analysis of the drought recovery of Andosols on southern Ecuadorian Andean páramos
Authors: Iñiguez Vicente , Morales Oscar , Cisneros Felipe , Bauwens Willy , Wyseure Guido
Published: June 2016

Abstract. The Neotropical Andean grasslands above 3500 m a.s.l., known as páramo, offer remarkable ecological services for the Andean region. The most important of these is the water supply of excellent quality to many cities and villages in the inter-Andean valleys and along the coast. The páramo ecosystem and especially its soils are under constant and increased threat by human activities and climate change. In this study, the recovery speed of the páramo soils after drought periods are analysed. The observation period includes the droughts of 2009, 2010, 2011, and 2012 together with intermediate wet periods. Two experimental catchments – one with and one without páramo – were investigated. The Probability Distributed Moisture (PDM) model was calibrated and validated in both catchments. Drought periods and its characteristics were identified and quantified by a threshold level approach and complemented by means of a drought propagation analysis. At the plot scale in the páramo region, the soil water content measured by time domain reflectometry (TDR) probes dropped from a normal value of about 0.84 to  ∼ 0.60 cm3 cm−3, while the recovery time was 2–3 months. This did not occur at lower altitudes (Cumbe) where the soils are mineral. Although the soil moisture depletion observed in these soils was similar to that of the Andosols (27 %), decreasing from a normal value of about 0.54 to  ∼ 0.39 cm3 cm−3, the recovery was much slower and took about 8 months for the drought in 2010. At the catchment scale, however, the soil water storage simulated by the PDM model and the drought analysis was not as pronounced. Soil moisture droughts occurred mainly in the dry season in both catchments. The deficit for all cases is small and progressively reduced during the wet season. Vegetation stress periods correspond mainly to the months of September, October and November, which coincides with the dry season. The maximum number of consecutive dry days were reached during the drought of 2009 and 2010 (19 and 22 days), which can be considered to be a long period in the páramo. The main factor in the hydrological response of these experimental catchments is the precipitation relative to the potential evapotranspiration. As the soils never became extremely dry nor close to the wilting point, the soil water storage capacity had a secondary influence.
An experimental seasonal hydrological forecasting system over the Yellow River basin – Part 2: The added value from climate forecast models
Authors: Yuan Xing
Published: June 2016

Abstract. This is the second paper of a two-part series on introducing an experimental seasonal hydrological forecasting system over the Yellow River basin in northern China. While the natural hydrological predictability in terms of initial hydrological conditions (ICs) is investigated in a companion paper, the added value from eight North American Multimodel Ensemble (NMME) climate forecast models with a grand ensemble of 99 members is assessed in this paper, with an implicit consideration of human-induced uncertainty in the hydrological models through a post-processing procedure. The forecast skill in terms of anomaly correlation (AC) for 2 m air temperature and precipitation does not necessarily decrease over leads but is dependent on the target month due to a strong seasonality for the climate over the Yellow River basin. As there is more diversity in the model performance for the temperature forecasts than the precipitation forecasts, the grand NMME ensemble mean forecast has consistently higher skill than the best single model up to 6 months for the temperature but up to 2 months for the precipitation. The NMME climate predictions are downscaled to drive the variable infiltration capacity (VIC) land surface hydrological model and a global routing model regionalized over the Yellow River basin to produce forecasts of soil moisture, runoff and streamflow. And the NMME/VIC forecasts are compared with the Ensemble Streamflow Prediction method (ESP/VIC) through 6-month hindcast experiments for each calendar month during 1982–2010. As verified by the VIC offline simulations, the NMME/VIC is comparable to the ESP/VIC for the soil moisture forecasts, and the former has higher skill than the latter only for the forecasts at long leads and for those initialized in the rainy season. The forecast skill for runoff is lower for both forecast approaches, but the added value from NMME/VIC is more obvious, with an increase of the average AC by 0.08–0.2. To compare with the observed streamflow, both the hindcasts from NMME/VIC and ESP/VIC are post-processed through a linear regression model fitted by using VIC offline-simulated streamflow. The post-processed NMME/VIC reduces the root mean squared error (RMSE) from the post-processed ESP/VIC by 5–15 %. And the reduction occurs mostly during the transition from wet to dry seasons. With the consideration of the uncertainty in the hydrological models, the added value from climate forecast models is decreased especially at short leads, suggesting the necessity of improving the large-scale hydrological models in human-intervened river basins.
Characteristics of rainfall events in RCM simulations for the Czech Republic
Authors: Svoboda Vojtěch , Hanel Martin , Máca Petr , Kyselý Jan
Published: June 2016

Abstract. Characteristics of rainfall events in an ensemble of 23 regional climate model (RCM) simulations are evaluated against observed data in the Czech Republic for the period 1981–2000. Individual rainfall events are identified using the concept of minimum inter-event time (MIT) and only heavy events during the warm season (May–September) are considered. Inasmuch as an RCM grid box represents a spatial average rather than a point measurement, the effects from areal averaging of rainfall data on characteristics of events are investigated using the observed data. Rainfall events from the RCM simulations are then compared to those from the at-site and area-average observations. Simulated number of heavy events and seasonal total precipitation due to heavy events are on average represented relatively well despite the higher spatial variation compared to observations. RCM-simulated event depths are comparable to the area-average observations, while event durations are overestimated and other characteristics related to rainfall intensity are significantly underestimated. Most of the rainfall event characteristics in the majority of the RCM simulations show a similar altitude-dependence pattern as in the observed data. The number of heavy events and seasonal total precipitation due to heavy events increase with altitude, and this dependence is captured better by the RCM simulations with higher spatial resolution.
DETECTION OF HARBOURS FROM HIGH RESOLUTION REMOTE SENSING IMAGERY VIA SALIENCY ANALYSIS AND FEATURE LEARNING
Authors: Wang Yetianjian , Pan Li , Wang Dagang , Kang Yifei
Published: June 2016

Abstract. Harbours are very important objects in civil and military fields. To detect them from high resolution remote sensing imagery is important in various fields and also a challenging task. Traditional methods of detecting harbours mainly focus on the segmentation of water and land and the manual selection of knowledge. They do not make enough use of other features of remote sensing imagery and often fail to describe the harbours completely. In order to improve the detection, a new method is proposed. First, the image is transformed to Hue, Saturation, Value (HSV) colour space and saliency analysis is processed via the generation and enhancement of the co-occurrence histogram to help detect and locate the regions of interest (ROIs) that is salient and may be parts of the harbour. Next, SIFT features are extracted and feature learning is processed to help represent the ROIs. Then, by using classified feature of the harbour, a classifier is trained and used to check the ROIs to find whether they belong to the harbour. Finally, if the ROIs belong to the harbour, a minimum bounding rectangle is formed to include all the harbour ROIs and detect and locate the harbour. The experiment on high resolution remote sensing imagery shows that the proposed method performs better than other methods in precision of classifying ROIs and accuracy of completely detecting and locating harbours.