bluuebunny/crossref_metadata_2025 huggingface dataset:
A comprehensive earthquake catalogue for northeastern British Columbia and western Alberta, 2014-2016
Authors: Visser R , Smith B , Kao H , Babaie Mahani A , Hutchinson J , McKay J E
Published: December 2017

To gain a better understanding of induced seismicity in northeast British Columbia and western Alberta, we conducted an intensive analysis of seismic data to locate earthquakes that occurred within the area of 52°N-61°N, 126°W-115°W for the
years of 2014 through 2016. Continuous seismic waveforms from as many as 43 stations operated by various organizations in the region were used in this study. A total of 5478 events were identified and located; but only 4916 solutions were deemed acceptable by our quality criteria. The number of
earthquakes in our final catalogue is approximately three times the base level of the Canadian National Seismograph Network catalogue. In this report, we describe in detail our location procedures and how each source parameter (origin time, epicenter, focal depth, and magnitude) is determined. The
earthquake catalogue is summarized in a table, while the phase picking data for individual events are presented in an ASCII file as a supplement to this report. The total numbers of events in 2014, 2015, and 2016 are 1287, 1575, and 2057, respectively. The overall magnitude of completeness of our
catalogue is ML 1.8, an improvement from the value of 2.3 for the CNSN catalogue.
Die Fresh Expression beweging en die Hervormde Kerk – ’n nuwe manier van kerkwees?
Authors: Ungerer André G.
Published: December 2017

The Fresh Expression movement is well-known in Great Britain and other Western countries like the USA, Australia and lately South Africa. During 2013, a task team launched two pilot courses in Cape Town and George that marked the beginning of Fresh Expressions in South Africa. The Nederduitsch Hervormde Kerk van Afrika (Netherdutch Reformed Church of Africa – NRCA) exposed 125 of her pastors to the Fresh Expression movement by means of the annual continuous theological training program during 2015. Three of the pastors underwent the ‘Train the Trainer’ course and are currently involved in the presentation of courses in the Pretoria region. The Fresh Expression movement hold the possibility for pioneers in church planting to reach the people who have no ties with the established church. By entering a certain context, faith communities are established by means of listening to the people in their context, serving them in a loving way, creating a community, evangelise and discipling them and starting their own unique way of worshipping. The new faith communities are not in competition with the established church but it is rather a question of a mixed economy where different types of church exists alongside each other in mutual respect and support. This study tries to establish basic criteria to distinguish a Fresh Expression from random missional outreaches by a congregation. Two potential Fresh Expressions in the NRCA were evaluated by the set criteria.
Perineal urethrostomy to treat obstructive urolithiasis in a captive hand-raised steenbok (Raphicerus campestris)
Authors: Poore Luke A. , Hendry Ross , Steyl Johan , Pfitzer Silke
Published: December 2017

The steenbok (Raphicerus campestris) is a small antelope of the family Bovidae native to the African continent. Urolithiasis, the formation of urinary calculi in the urinary tract, can be caused by a variety of factors such as diet, dehydration, infection and anatomical predisposition. Urolithiasis, with uroliths identified as magnesium calcium phosphate carbonate in composition, was diagnosed in a hand-reared 5-month-old steenbok. Perineal urethrostomy was performed as a component of the broad treatment regime that included fluid therapy, antibiotic and anti-inflammatory treatment. However, the animal died 4 days later as a result of systemic hypoxia and energy depletion because of stress and cachexia. The challenges of post-surgical treatment, the importance of positive energy balance in small ruminants under stressful circumstances, as well as the role of diet of hand-reared antelope in predisposition to urolith formation are highlighted.
Assessing the role of socio-economic values on entrepreneurial intentions among university students in Cape Town
Authors: Kalitanyi Vivence , Bbenkele Edwin
Published: December 2017

Background: This article presents the findings of an empirical fieldwork study conducted in Cape Town, South Africa.Aim: The aim of the study was to establish how socio-economic values (income, economic development, employment or unemployment in the university students’ direct environment) shape their entrepreneurial intentions.Setting and method: The study was built on Ajzen’ psychological model on entrepreneurial intentions, and used a semi-structured questionnaire to collect data from 274 entrepreneurship university students. Cronbach’s alpha was used to measure the reliability of the questionnaire, where six variables out of nine, had a coefficient alpha of more than 0.7, while the remaining three had a coefficient alpha of between 0.5 and 0.7. This instrument was assessed by both statisticians and academics who are experts in their fields to ensure its validity. Multivariate tests of statistical significance were conducted, where correlation and regression statistics were used to analyse the data.Results: Findings suggest that socio-economic factors have an impact in shaping entrepreneurial intentions of the university students.Conclusion: The study formulates the recommendations to the government, businesses, civil society organisations as well as the community within which students live.
Bone turnover markers in HIV-infected women on tenofovir-based antiretroviral therapy
Authors: Mulubwa Mwila , Viljoen Michelle , Kruger Iolanthe M. , Kruger Herculina S. , Rheeders Malie
Published: December 2017

Background: Tenofovir disoproxil fumarate (TDF) antiretroviral therapy is associated with disruption of the bone turnover process.Objectives: The objective of this study was to determine the association between tenofovir (TFV) plasma concentration and various bone turnover markers and compare these markers in HIV-infected women and HIV-uninfected controls.Method: A cross-sectional sub-study included 30 HIV-infected women on TDF and 30 HIV-uninfected matched participants. Serum calcium (SrCa), serum phosphate (SrP), C-terminal telopeptide (CTx), parathyroid hormone (PTH), alkaline phosphatase (ALP), C-reactive protein (CRP), vitamin D (VitD) and bone mineral density (BMD) were measured. Plasma TFV was assayed on HPLC-MS/MS. The statistical tests applied were Mann–Whitney test, unpaired t-test, analysis of covariance, regression and correlation analysis.Results: In HIV-infected women, no correlation existed between plasma TFV concentration and CTx, PTH, ALP, SrCa, SrP, VitD or BMD (p > 0.05). After adjusting for smoking and alcohol use, ALP (p < 0.001), CTx (p = 0.027) and PTH (p = 0.050) were significantly higher in HIV-infected compared to HIV-uninfected women. Women with TFV concentration ≥ 120 ng/mL had higher PTH concentrations (p = 0.037) compared to those with ≤ 100 ng/mL. Significant correlations between SrCa and PTH and SrCa and SrP including CTx and PTH (p < 0.05) were present in HIV-uninfected women while absent in HIV-infected counterparts (p > 0.05).Conclusion: The results indicate possible increased bone turnover at higher TFV concentrations. The normal regular bone turnover processes in HIV-infected women on TDF therapy are altered. Larger studies are warranted to confirm these results.
A comparative study of human T-cell lymphotropic virus-associated myelopathy in HIV-positive and HIV-negative patients in KwaZulu-Natal
Authors: Paruk Hoosain F. , Bhigjee Ahmed I. , Marais Suzaan
Published: December 2017

Background: KwaZulu-Natal is an endemic area for HIV and human T-cell lymphotropic virus (HTLV) infection. The main neurological manifestation of HTLV is HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The effect of HIV co-infection in patients with HAM/TSP is not well documented.Aims: To determine the prevalence of HIV seropositivity in patients with HAM/TSP and compare the clinical, laboratory and radiological features of patients mono-infected with HTLV and those dually infected with HTLV and HIV.Methods: Adult patients referred to the Neurology Department at Inkosi Albert Luthuli Central Hospital in KwaZulu-Natal, South Africa, for the period 01 January 2004 to 31 December 2015 with a positive HTLV serology were identified from the National Health Laboratory Service database. A retrospective chart review was conducted to identify all patients who had a diagnosis of HAM/TSP and to record their HIV status. Clinical, laboratory and radiological data were compared for HIV-positive and HIV-negative patients.Results: A total of 52 patients with HAM/TSP were identified. HIV results were available in 44 patients of whom 23 (52%) patients were HIV co-infected. Patients who were HIV-positive had a younger age of presentation compared to HIV-negative patients (median: 31 vs 50 years, p = 0.002). HIV-positive patients had a median duration of symptoms at presentation of 12 months compared to 16 months for HIV-negative patients, but the difference did not reach statistical significance (p = 0.082). The CD4 cell counts of HIV-positive patients were well preserved with a median count of 781 cells/µL.Conclusions: HIV co-infection is commonly seen in the setting of HAM/TSP in KwaZulu-Natal. An interaction between the viruses may accelerate the development of HAM/TSP, leading to a younger age of presentation. Co-infection may have treatment implications because of CD4 counts being preserved in these patients.
Ends of Schreier graphs and cut-points of limit spaces of self-similar groups
Authors: Bondarenko Ievgen , D'Angeli Daniele , Nagnibeda Tatiana
Published: December 2017

Every self-similar group acts on the space

X^\omega

of infinite words over some alphabet

X

. We study the Schreier graphs

\Gamma_w

for

w\in X^\omega

of the action of self-similar groups generated by bounded automata on the space

X^\omega

. Using sofic subshifts we determine the number of ends for every Schreier graph

\Gamma_w

. Almost all Schreier graphs

\Gamma_w

with respect to the uniform measure on

X^\omega

have one or two ends, and we characterize bounded automata whose Schreier graphs have two ends almost surely. The connection with (local) cut-points of limit spaces of self-similar groups is established.
О проверяющих тестах размыкания для контактных схем
Authors: Popkov Kirill Andreevich
Published: December 2017

Рассматривается задача синтеза двухполюсных контактных схем, реализующих заданные булевы функции и допускающих короткие проверяющие тесты относительно размыканий контактов. Для каждой булевой функции от $n$ переменных найдены минимально возможные значения длин единичного и полного проверяющего тестов. В частности, доказано, что они не превосходят $n$.
Обобщение одного метода восстановления ключа фильтрующего генератора
Authors: Alekseev Evgeny Konstantinovich , Kuschinskaja Lyudmila A
Published: December 2017

Описан алгоритм, который является обобщением одного ранее предложенного метода восстановления ключа фильтрующего генератора, основанного на аппроксимации функции усложнения с помощью алгебраически вырожденных функций. Получены оценки трудоемкости, надежности и объема используемой предложенным методом памяти. Приведены примеры его использования, в частности, для анализа шифра LILI-128.
Les deux visages de l’écologie : conséquence sur l’éthique du rapport Humains-Animaux
Authors: Catsaras Marc
Published: December 2017

Les deux conceptions de l’écologie : l’“écologie environnementale” et l’“écologie profonde” sont examinées dans une perspective historique d’une part, dans leurs aspects actuels d’autre part. Les conséquences, enfin, sur l’éthique du rapport Humains-Animaux sont discutées, en particulier la question : droits des animaux ou animaux sujets de droit.
Mise en évidence d’Érysipelothrix rhusiopathiae dans des élevages de porcs, dindes et canards porteurs sains. Premiers résultats
Authors: Vaissaire Josée , Baroux Daniel , Salingardes François , Thong Ponhak-Raingser , Le Doujet Claudine , Mendy Christiane , Peigné Flavien , Chevalerias Hervé
Published: December 2017

Les auteurs ont fait une pré-enquête sur des lots de canards, dindes, porcs et pintades pour apprécier le portage d'Erysipelothrix rhusiopathiæ sur des animaux apparemment sains. Deux milieux sélectifs ont été testés, un classiquement décrit et un expérimental. 28 % des animaux se sont révélés porteurs. Les prélèvements étaient soit du contenu intestinal, soit des cœurs.
Approche expérimentale de l’érection réflexe chez le rat
Authors: Rampin Olivier , Bernabe Jacques , Gougis Sylvette , Rousseau Jean-Paul
Published: December 2017

Les fibres du nerf dorsal du pénis véhiculent la sensibilité du pénis et constituent le versant afférent des réflexes sexuels. Leur stimulation par des chocs de faible durée provoque une augmentation réflexe de la pression intracaverneuse, qui est supprimée par la section bilatérale des nerfs pelviens efférents. Lorsqu’on augmente la durée des chocs, la réponse réflexe n’est obtenue qu’après section de la moelle en T8, suggérant la possibilité d’un contrôle inhibiteur descendant de ce réflexe d’érection.

Chez les rats spinaux, la réponse réflexe diminue d’amplitude, lorsque l’on augmente l’intensité de la stimulation. Cette inhibition segmentaire n’est pas due au recrutement de fibres sensitives inhibitrices. Elle pourrait résulter de la mise en jeu d’un réflexe sympathique antiérectile s’opposant au réflexe d’érection.
Étude statistique de l’évolution sur 9 ans et des fluctuations saisonnières des notes NORECOIN en restauration collective sociale
Authors: Leprêtre Alain , Catsaras Marc
Published: December 2017

La méthode d’analyse NORECOIN (normalisée, répétitive, codée et intégrée) a été appliquée de 1985 à 1993 à un grand échantillon de restaurants de la restauration collective sociale. L’évolution des notes suit une courbe en S de pente variable suivant les groupes de restaurants concernés et suivant les saisons. Depuis 1988-89, il n’y a plus de fluctuations saisonnières de la qualité microbiologique des plats. À partir des données de 1988 à 1993, il est possible d’établir, à l’usage des collectivités, des abaques permettant de situer leurs performances par rapport aux autres professionnels. Ces abaques peuvent être réalisées par catégories de restaurants ou par saison.
Delacroix au Maroc face au cheval dans la culture humaine
Authors: Rousseau Michel
Published: December 2017

La présentation des chevaux dans l’Exposition sur “Delacroix au Maroc”, en 1832, parue ici (1994, p. 405-406), est suivie d’un prolongement culturel. I. Sur les emplois comparés du cheval marocain et des nôtres. II. Sur l’esthétique choisie, surtout dans l’orientalisme. Ainsi deux civilisations se distinguent.
Mediating Effect of Repeated Tuberculosis Exposure on the Risk of Transmission to Household Contacts of Multidrug-Resistant Tuberculosis Patients
Authors: Lu Peng , Ding Xiaoyan , Liu Qiao , Lu Wei , Martinez Leonardo , Sun Jiansheng , Lu Feng , Zhong Chongqiao , Jiang Hui , Miao Changdong , Zhu Limei , Yang Haitao
Published: December 2017

Primary Mycobacterium tuberculosis transmission is an important driver of the global epidemic of resistance to tuberculosis drugs. A few studies have compared tuberculosis infection in contacts of index cases with different drug-resistant profiles, suggesting that contacts of multidrug-resistant (MDR) tuberculosis cases are at higher risk. Repeated tuberculosis exposure in contacts of MDR tuberculosis patients through recurrent tuberculosis may modify this relationship. We compared tuberculosis infection in household contacts of MDR and drug-susceptible (DS) tuberculosis patients from six cities in southeastern China and investigated whether repeated tuberculosis exposure was a mediating factor. Tuberculosis infection was defined as a tuberculin skin test induration ≥ 10 mm. In all, 111 (28.0%) of 397 household contacts of MDR tuberculosis patients and 165 (24.7%) of 667 contacts of DS tuberculosis index cases were infected with tuberculosis. In a multivariate model not including the previous tuberculosis exposure, contacts of MDR tuberculosis patients had a higher likelihood of tuberculosis infection (adjusted odds ratio [AOR] = 1.37; 95% confidence interval [CI] = 1.01–1.84; P = 0.041). In a separate multivariate model adjusted for the previous tuberculosis exposure, the odds ratio of tuberculosis infection flipped and contacts of MDR cases were now at lower risk for tuberculosis infection (AOR = 0.55; 95% CI = 0.38–0.81; P = 0.003). These findings suggest prior tuberculosis exposure in contacts strongly mediates the relationship between tuberculosis infection and the index drug resistance profile. Prior studies showing lower risk of developing tuberculosis among contacts of MDR tuberculosis patients may be partially explained by a lower rate of tuberculosis infection at baseline.
High Prevalence of Shigella or Enteroinvasive Escherichia coli Carriage among Residents of an Internally Displaced Persons Camp in South Sudan
Authors: Bliss Jesse , Bouhenia Malika , Hale Peter , Couturier Brianne A. , Iyer Anita S. , Rumunu John , Martin Stephen , Wamala Joseph F. , Abubakar Abdinasir , Sack David A. , Luquero Francisco J. , Couturier Marc Roger , Azman Andrew S. , Leung Daniel T.
Published: December 2017

Displaced persons living in camps are at an increased risk of diarrheal diseases. Subclinical carriage of pathogens may contribute to the spread of disease, especially for microbes that require a low infectious dose. Multiplex real-time polymerase chain reaction was performed to detect a panel of 20 bacterial, viral, and protozoal targets, and we report a high prevalence of enteropathogen carriage, including Shigella spp. or enteroinvasive Escherichia coli in 14%, among a sample of 88 asymptomatic individuals in an internally displaced persons camp in South Sudan. Further studies are needed to determine the contribution of such carriage to the spread of disease.
Rotavirus Vaccine will Improve Child Survival by More than Just Preventing Diarrhea: Evidence from Bangladesh
Authors: Saha Senjuti , Santosham Mathuram , Hussain Manzoor , Black Robert E. , Saha Samir K.
Published: December 2017

Despite the high burden of rotavirus diarrhea, uptake of rotavirus vaccines in Asia remains low. This primarily stems from a perception of rotavirus as a non-life-threatening pathogen amidst a background of competing health priorities and limited resources. In the largest pediatric hospital of Bangladesh, where there is a fierce competition for beds, we found that between November 2015 and October 2016, 12% of 23,064 admissions were due to gastrointestinal infections, 54% of which were caused by rotavirus. One in four cases requiring hospitalization, or 5,879 cases, was refused because of unavailability of beds. Most refused cases were of pneumonia (22%), severe perinatal asphyxia (17%), preterm birth complications (7%), and meningitis (2%), all of which bear high risks of death or disability, if not treated timely. When determining vaccine policies and conducting vaccine impact studies, it would be shortsighted to not consider the impact on morbidity and mortality of cases that are refused admission because of the hospitalization of children with a preventable disease as rotavirus diarrhea. In our hospital, routine use of a rotavirus vaccine with 41% efficacy will release 629 beds per year to accommodate previously refused cases. Based on evidence, we make the case that introduction of this vaccine in Bangladesh and the surrounding region will prevent morbidity and mortality, both directly and indirectly, and help us ensure survival and well-being of all children.
Estudio de la severidad post-incendio en la Comunidad Valenciana comparando los índices dNBR, RdNBR y RBR a partir de imágenes Landsat 8
Authors: Botella-Martínez M. A. , Fernández-Manso A.
Published: December 2017

In Mediterranean territories, with their characteristic climate that implies long periods of drought and rains often concentrated in torrential episodes, forest managers are faced with a series of decisions that can be urgent after a wildfire, some of them strongly correlated with the degree of damage caused by fire. In this sense, the object of this study was to provide a fast and reliable tool for the initial assessment of post-fire severity in these kinds of territories, by means of remote sensing techniques. Using Landsat 8 imagery, we have calculated three fire severity indices (dNBR, RdNBR, and RBR) for nine fires occurred in the Valencia region, a typical Mediterranean area. For each index, post-fire severity classification thresholds have been obtained taking into account the following categories: unburned, low, moderate, and high. These thresholds have been validated using, as ground-reference, aerial photographs taken from a helicopter. Afterwards, the degree to which post-fire severity was influenced by factors associated with pre-fire vegetation was evaluated, using a variance analysis. This analysis served to compare the three indices in terms of their robustness against the influence of these factors. With the obtained data, and with the study of classification accuracies employing the Kappa statistic, we were able to propose the most suitable index for calculating post-fire severity in the Valencia region, along with its operating thresholds. The findings suggest that the results could be extrapolated to other areas of similar characteristics.
Ajuste de metodologías para evaluar severidad de quemado en zonas semiáridas (SE peninsular): incendio Donceles 2012
Authors: Gómez-Sánchez E. , De las Heras J. , Lucas-Borja M. , Moya D.
Published: December 2017

Post-fire management should be based on a proper evaluation of fire damage (burn severity), mainly for Large Fires (>500 ha). Several methodologies have been developed based on remote sensing information validated with fieldwork. The most widespread techniques was the assessment of fire severity indices obtained from remote sensing. It allow a quick assessment of large areas at affordable costs, although the analysis of soil burn severity and the degree of agreement with the ground truth is not fully reliable. Our study case was the Donceles fire (summer 2012, Hellín, Albacete). The post-fire restoration planning, emergency actions, was based on cartographic information of burn severity. To optimize results in a short time and low budget, we applied methodologies in a similar way other similar fires in the Mediterranean peninsular area. We assessed burn severity by using spectral indices (NDVI, dNBR, RdNBR and RBR) and images from Landsat-7 (including banded) and Deimos-1. For each index, we developed both supervised and unsupervised classifications, using field data as training areas. The highest overall reliability values were found for dNBR (79%) and NBR (71%), obtaining low values with RdNBR. In all cases, the reliability was higher using the supervised classification, so using real-ground data to identify the categories of severity to be discriminated. We conclude the need to extend fire studies in our area to improve the reliability of the fire severity assessment obtained from spectral indexes, thus establishing a protocol of data collection and standard methodology of calculation adapted to the characteristics of the region.
A more representative “best representative value” for daily total column ozone reporting
Authors: Smedley Andrew R. D. , Rimmer John S. , Webb Ann R.
Published: December 2017

Abstract. Long-term trends of total column ozone (TCO), assessments of stratospheric ozone recovery, and satellite validation are underpinned by a reliance on daily best representative values from Brewer spectrophotometers and other ground-based ozone instruments. In turn reporting of these daily total column ozone values to the World Ozone and Ultraviolet Radiation Data Centre (WOUDC) has traditionally been predicated upon a simple choice between direct sun (DS) and zenith sky (ZS) observations. For mid- and high-latitude monitoring sites impacted by cloud cover we discuss the potential deficiencies of this approach in terms of its rejection of otherwise valid observations and capability to evenly sample throughout the day. A new methodology is proposed that makes full use of all valid direct sun and zenith sky observations, accounting for unevenly spaced observations and their relative uncertainty, to calculate an improved estimate of the daily mean total column ozone. It is demonstrated that this method can increase the number of contributing observations by a factor of 2.5, increases the sampled time span, and reduces the spread of the representative time by half. The largest improvements in the daily mean estimate are seen on days with the smallest number of contributing direct sun observations. No effect on longer-term trends is detected, though for the sample data analysed we observe a mean increase of 2.8 DU (0.82 %) with respect to the traditional direct sun vs. zenith sky average choice. To complement the new calculation of a best representative value of total column ozone and separate its uncertainty from the spread of observations, we also propose reporting its standard error rather than the standard deviation, together with measures of the full range of values observed.
Detection of carbon monoxide pollution from megacities and wildfires on regional and urban scale: The benefit of CO column retrievals from SCIAMACHY 2.3 μm measurements under cloudy conditions
Authors: Borsdorff Tobias , Andrasec Josip , aan de Brugh Joost , Hu Haili , Aben Ilse , Landgraf Jochen
Published: December 2017

Abstract. In the perspective of the upcoming Sentinel-5 Precursor carbon monoxide data product, we discuss the benefit of CO total column retrievals from cloud contaminated SCIAMACHY 2.3 micron shortwave infrared spectra to detect atmospheric CO enhancements on regional and urban scales due to emissions from megacities and wildfires. The study uses the operational Sentinel-5 Precursor algorithm SICOR, which infers the vertically integrated CO column together with effective cloud parameters. We investigate the capability to detect localized CO enhancements distinguishing between clear-sky observations and observations with low and medium-high clouds. Exemplary, we analyze CO enhancements over the megacities Paris, Los Angeles, and Tehran as well as the wildfire events in Mexico/Guatemala 2005 and Alaska/Canada 2004. The CO average of the SCIAMACHY full mission data set of clear-sky observations can detect weak CO enhancements of less than 10 ppb due to air pollution in these cities. For low cloud conditions, the CO data product performs similarly well. For medium-high clouds, the observations show a reduced CO signal both over Tehran and Los Angeles, while for Paris no significant CO enhancement can be detected. This indicates that information about the vertical distribution of CO can be obtained from the SCIAMACHY measurements. Moreover, for the Mexico/Guatemala fires, the low-cloud CO data captures a strong outflow of CO over the Gulf of Mexico and the Pacific Ocean and so provides complementary information to clear-sky retrievals. For both burning events, enhanced CO values are even detectable with medium-high cloud retrievals, confirming a distinct vertical extension of the pollution. The larger number of additional measurements and hence the better spatial coverage, improves significantly the detection of wild fire pollution using both the clear-sky and cloudy CO retrievals. Due to the improved instrument performance of the TROPOMI instrument with respect to its precursor SCIAMACHY, the upcoming Sentinel-5 Precursor CO data product will allow to detect CO emission and its vertical extension of many more cities and wildfires and so opens new research opportunities.
Design of a carrier-depletion Mach-Zehnder modulator in 250 nm silicon-on-insulator technology
Authors: Félix Rosa María , Rathgeber Lotte , Elster Raik , Hoppe Niklas , Föhn Thomas , Schmidt Martin , Vogel Wolfgang , Berroth Manfred
Published: December 2017

Abstract. We present the design of a single-drive Mach-Zehnder modulator for amplitude modulation in silicon-on-insulator technology with 250 nm active layer thickness. The applied RF signal modulates the carrier density in a reverse biased lateral pn-junction. The free carrier plasma dispersion effect in silicon leads to a change in the refractive index. The modulation efficiency and the optical loss due to free carriers are analyzed for different doping configurations. The intrinsic electrical parameters of the pn-junction of the phase shifter like resistance and capacitance and the corresponding RC-limit are studied. A first prototype in this technology fabricated at the IMS CHIPS Stuttgart is successfully measured. The structure has a modulation efficiency of VπL = 3.1 V ⋅ cm at 2 V reverse bias. The on-chip insertion loss is 4.2 dB. The structure exhibits an extinction ratio of around 32 dB. The length of the phase shifter is 0.5 mm. The cutoff frequency of the entire modulator is 30 GHz at 2 V. Finally, an optimization of the doping structure is presented to reduce the optical loss and to improve the modulation efficiency. The optimized silicon optical modulator shows a theoretical modulation efficiency of VπL = 1.8 V ⋅ cm at 6 V bias and a maximum optical loss due to the free carrier absorption of around 3.1 dB cm−1. An ultra-low fiber-to-fiber loss of approximately 4.8 dB is expected using the state of the art optical components in the used technology.
Ideas and perspectives: Hydrothermally driven redistribution and sequestration of early Archaean biomass – the hydrothermal pump hypothesis
Authors: Duda Jan-Peter , Thiel Volker , Bauersachs Thorsten , Mißbach Helge , Reinhardt Manuel , Schäfer Nadine , Van Kranendonk Martin J. , Reitner Joachim
Published: December 2017

Abstract. Archaean hydrothermal chert veins commonly contain abundant organic carbon of uncertain origin (abiotic vs. biotic). In this study, we analysed kerogen contained in a hydrothermal chert vein from the ca. 3.5 Ga old Dresser Formation (Pilbara Craton, Western Australia). Catalytic hydropyrolysis (HyPy) of this kerogen yielded n-alkanes up to n-C22, with a sharp decrease in abundance beyond n-C18. A very similar distribution (≤ n-C18) was observed in HyPy products of pre-extracted recent bacterial biomass, while abiotic compounds synthesised via Fischer-Tropsch-type synthesis exhibited a modal distribution. We therefore propose that the original organic matter in the Archaean chert veins has a primarily microbial origin. We hypothesise that the microbially-derived organic matter accumulated in different aquatic and subsurface Dresser environments, and was then assimilated, redistributed and sequestered by hydrothermal fluids (hydrothermal pump hypothesis).
The potential of using remote sensing data to estimate air–sea CO2 exchange in the Baltic Sea
Authors: Parard Gaëlle , Rutgersson Anna , Raj Parampil Sindu , Charantonis Anastase Alexandre
Published: December 2017

Abstract. In this article, we present the first climatological map of air–sea CO2 flux over the Baltic Sea based on remote sensing data: estimates of pCO2 derived from satellite imaging using self-organizing map classifications along with class-specific linear regressions (SOMLO methodology) and remotely sensed wind estimates. The estimates have a spatial resolution of 4 km both in latitude and longitude and a monthly temporal resolution from 1998 to 2011. The CO2 fluxes are estimated using two types of wind products, i.e. reanalysis winds and satellite wind products, the higher-resolution wind product generally leading to higher-amplitude flux estimations. Furthermore, the CO2 fluxes were also estimated using two methods: the method of Wanninkhof et al. (2013) and the method of Rutgersson and Smedman (2009). The seasonal variation in fluxes reflects the seasonal variation in pCO2 unvaryingly over the whole Baltic Sea, with high winter CO2 emissions and high pCO2 uptakes. All basins act as a source for the atmosphere, with a higher degree of emission in the southern regions (mean source of 1.6 mmol m−2 d−1 for the South Basin and 0.9 for the Central Basin) than in the northern regions (mean source of 0.1 mmol m−2 d−1) and the coastal areas act as a larger sink (annual uptake of −4.2 mmol m−2 d−1) than does the open sea (−4 mmol m−2 d−1). In its entirety, the Baltic Sea acts as a small source of 1.2 mmol m−2 d−1 on average and this annual uptake has increased from 1998 to 2012.
Unravelling earth flow dynamics with 3-D time series derived from UAV-SfM models
Authors: Clapuyt François , Vanacker Veerle , Schlunegger Fritz , Van Oost Kristof
Published: December 2017

Abstract. Accurately assessing geo-hazards and quantifying landslide risks in mountainous environments are gaining importance in the context of the ongoing global warming. For an in-depth understanding of slope failure mechanisms, accurate monitoring of the mass movement topography at high spatial and temporal resolutions remains essential. The choice of the acquisition framework for high-resolution topographic reconstructions will mainly result from the trade-off between the spatial resolution needed and the extent of the study area. Recent advances in the development of unmanned aerial vehicle (UAV)-based image acquisition combined with the structure-from-motion (SfM) algorithm for three-dimensional (3-D) reconstruction make the UAV-SfM framework a competitive alternative to other high-resolution topographic techniques. In this study, we aim at gaining in-depth knowledge of the Schimbrig earthflow located in the foothills of the Central Swiss Alps by monitoring ground surface displacements at very high spatial and temporal resolution using the efficiency of the UAV-SfM framework. We produced distinct topographic datasets for three acquisition dates between 2013 and 2015 in order to conduct a comprehensive 3-D analysis of the landslide. Therefore, we computed (1) the sediment budget of the hillslope, and (2) the horizontal and (3) the three-dimensional surface displacements. The multitemporal UAV-SfM based topographic reconstructions allowed us to quantify rates of sediment redistribution and surface movements. Our data show that the Schimbrig earthflow is very active, with mean annual horizontal displacement ranging between 6 and 9 m. Combination and careful interpretation of high-resolution topographic analyses reveal the internal mechanisms of the earthflow and its complex rotational structure. In addition to variation in horizontal surface movements through time, we interestingly showed that the configuration of nested rotational units changes through time. Although there are major changes in the internal structure of the earthflow in the 2013–2015 period, the sediment budget of the drainage basin is nearly in equilibrium. As a consequence, our data show that the time lag between sediment mobilization by landslides and enhanced sediment fluxes in the river network can be considerable.
Compiled records of carbon isotopes in atmospheric CO2 for historical simulations in CMIP6
Authors: Graven Heather , Allison Colin E. , Etheridge David M. , Hammer Samuel , Keeling Ralph F. , Levin Ingeborg , Meijer Harro A. J. , Rubino Mauro , Tans Pieter P. , Trudinger Cathy M. , Vaughn Bruce H. , White James W. C.
Published: December 2017

Abstract. The isotopic composition of carbon (Δ14C and δ13C) in atmospheric CO2 and in oceanic and terrestrial carbon reservoirs is influenced by anthropogenic emissions and by natural carbon exchanges, which can respond to and drive changes in climate. Simulations of 14C and 13C in the ocean and terrestrial components of Earth system models (ESMs) present opportunities for model evaluation and for investigation of carbon cycling, including anthropogenic CO2 emissions and uptake. The use of carbon isotopes in novel evaluation of the ESMs' component ocean and terrestrial biosphere models and in new analyses of historical changes may improve predictions of future changes in the carbon cycle and climate system. We compile existing data to produce records of Δ14C and δ13C in atmospheric CO2 for the historical period 1850–2015. The primary motivation for this compilation is to provide the atmospheric boundary condition for historical simulations in the Coupled Model Intercomparison Project 6 (CMIP6) for models simulating carbon isotopes in the ocean or terrestrial biosphere. The data may also be useful for other carbon cycle modelling activities.
The ABC model: a non-hydrostatic toy model for use in convective-scale data assimilation investigations
Authors: Petrie Ruth Elizabeth , Bannister Ross Noel , Cullen Michael John Priestley
Published: December 2017

Abstract. In developing methods for convective-scale data assimilation (DA), it is necessary to consider the full range of motions governed by the compressible Navier–Stokes equations (including non-hydrostatic and ageostrophic flow). These equations describe motion on a wide range of timescales with non-linear coupling. For the purpose of developing new DA techniques that suit the convective-scale problem, it is helpful to use so-called toy models that are easy to run and contain the same types of motion as the full equation set. Such a model needs to permit hydrostatic and geostrophic balance at large scales but allow imbalance at small scales, and in particular, it needs to exhibit intermittent convection-like behaviour. Existing toy models are not always sufficient for investigating these issues. A simplified system of intermediate complexity derived from the Euler equations is presented, which supports dispersive gravity and acoustic modes. In this system, the separation of timescales can be greatly reduced by changing the physical parameters. Unlike in existing toy models, this allows the acoustic modes to be treated explicitly and hence inexpensively. In addition, the non-linear coupling induced by the equation of state is simplified. This means that the gravity and acoustic modes are less coupled than in conventional models. A vertical slice formulation is used which contains only dry dynamics. The model is shown to give physically reasonable results, and convective behaviour is generated by localised compressible effects. This model provides an affordable and flexible framework within which some of the complex issues of convective-scale DA can later be investigated. The model is called the ABC model after the three tunable parameters introduced: A (the pure gravity wave frequency), B (the modulation of the divergent term in the continuity equation), and C (defining the compressibility).
What does nature have to do with it? Reconsidering distinctions in international disaster response frameworks in the Danube basin
Authors: McClain Shanna N. , Secchi Silvia , Bruch Carl , Remo Jonathan W. F.
Published: December 2017

Abstract. This article examines the international policy and institutional frameworks for response to natural and man-made disasters occurring in the Danube basin and the Tisza sub-basin, two transnational basins. Monitoring and response to these types of incidents have historically been managed separately. We discuss whether the policy distinctions in response to natural and man-made disasters remain functional given recent international trends toward holistic response to both kinds of disasters. We suggest that these distinctions are counterproductive, outdated, and ultimately flawed, illustrate some of the specific gaps in the Danube and the Tisza, and conclude by proposing an integrated framework for disaster response in the Danube basin and Tisza sub-basin.
Centuries of intense surface melt on Larsen C Ice Shelf
Authors: Bevan Suzanne L. , Luckman Adrian , Hubbard Bryn , Kulessa Bernd , Ashmore David , Kuipers Munneke Peter , O'Leary Martin , Booth Adam , Sevestre Heidi , McGrath Daniel
Published: December 2017

Abstract. Following a southward progression of ice-shelf disintegration along the Antarctic Peninsula (AP), Larsen C Ice Shelf (LCIS) has become the focus of ongoing investigation regarding its future stability. The ice shelf experiences surface melt and commonly features surface meltwater ponds. Here, we use a flow-line model and a firn density model (FDM) to date and interpret observations of melt-affected ice layers found within five 90 m boreholes distributed across the ice shelf. We find that units of ice within the boreholes, which have densities exceeding those expected under normal dry compaction metamorphism, correspond to two climatic warm periods within the last 300 years on the Antarctic Peninsula. The more recent warm period, from the 1960s onwards, has generated distinct sections of dense ice measured in two boreholes in Cabinet Inlet, which is close to the Antarctic Peninsula mountains – a region affected by föhn winds. Previous work has classified these layers as refrozen pond ice, requiring large quantities of mobile liquid water to form. Our flow-line model shows that, whilst preconditioning of the snow began in the late 1960s, it was probably not until the early 1990s that the modern period of ponding began. The earlier warm period occurred during the 18th century and resulted in two additional sections of anomalously dense ice deep within the boreholes. The first, at 61 m in one of our Cabinet Inlet boreholes, consists of ice characteristic of refrozen ponds and must have formed in an area currently featuring ponding. The second, at 69 m in a mid-shelf borehole, formed at the same time on the edge of the pond area. Further south, the boreholes sample ice that is of an equivalent age but which does not exhibit the same degree of melt influence. This west–east and north–south gradient in the past melt distribution resembles current spatial patterns of surface melt intensity.
Satellite-derived submarine melt rates and mass balance (2011–2015) for Greenland's largest remaining ice tongues
Authors: Wilson Nat , Straneo Fiammetta , Heimbach Patrick
Published: December 2017

Abstract. Ice-shelf-like floating extensions at the termini of Greenland glaciers are undergoing rapid changes with potential implications for the stability of upstream glaciers and the ice sheet as a whole. While submarine melting is recognized as a major contributor to mass loss, the spatial distribution of submarine melting and its contribution to the total mass balance of these floating extensions is incompletely known and understood. Here, we use high-resolution WorldView satellite imagery collected between 2011 and 2015 to infer the magnitude and spatial variability of melt rates under Greenland's largest remaining ice tongues – Nioghalvfjerdsbræ (79 North Glacier, 79N), Ryder Glacier (RG), and Petermann Glacier (PG). Submarine melt rates under the ice tongues vary considerably, exceeding 50 m a−1 near the grounding zone and decaying rapidly downstream. Channels, likely originating from upstream subglacial channels, give rise to large melt variations across the ice tongues. We compare the total melt rates to the influx of ice to the ice tongue to assess their contribution to the current mass balance. At Petermann Glacier and Ryder Glacier, we find that the combined submarine and aerial melt approximately balances the ice flux from the grounded ice sheet. At Nioghalvfjerdsbræ the total melt flux (14.2 ± 0.96 km3 a−1 w.e., water equivalent) exceeds the inflow of ice (10.2 ± 0.59 km3 a−1 w.e.), indicating present thinning of the ice tongue.
Profiles of mapping of content creators in a geo-social network: The case of 21 Brazilian cities
Authors: Morais Aline Marques , Andrade Nazareno
Published: December 2017

A geo-social network (GSN) is a type of social network where geolocated information shared among users plays an important role. The fast development of GSNs in recent years has made this system a valuable tool for people to learn about places on a large scale, using information provided by non-specialists. This paper examines how value is created in GSNs by studying the collective behavior of content creators in a popular GSN, Foursquare. In particular, this study examines the multifaceted aspect of content contribution behavior, and investigates how it occurs in multiple cities of an area previously studied by few: 21 medium- and large-sized Brazilian cities. Our study leverages cluster analyses to explain how users differ in how they collaborate. We discovered four profiles of content creators, and identify how such profiles are useful to GSNs.
Stewardship in the "Age of Algorithms"
Authors: Lynch Clifford
Published: December 2017

This paper explores pragmatic approaches that might be employed to document the behavior of large, complex socio-technical systems (often today shorthanded as “algorithms”) that centrally involve some mixture of personalization, opaque rules, and machine learning components. Thinking rooted in traditional archival methodology — focusing on the preservation of physical and digital objects, and perhaps the accompanying preservation of their environments to permit subsequent interpretation or performance of the objects — has been a total failure for many reasons, and we must address this problem. The approaches presented here are clearly imperfect, unproven, labor-intensive, and sensitive to the often hidden factors that the target systems use for decision-making (including personalization of results, where relevant); but they are a place to begin, and their limitations are at least outlined. Numerous research questions must be explored before we can fully understand the strengths and limitations of what is proposed here. But it represents a way forward. This is essentially the first paper I am aware of which tries to effectively make progress on the stewardship challenges facing our society in the so-called “Age of Algorithms;” the paper concludes with some discussion of the failure to address these challenges to date, and the implications for the roles of archivists as opposed to other players in the broader enterprise of stewardship — that is, the capture of a record of the present and the transmission of this record, and the records bequeathed by the past, into the future. It may well be that we see the emergence of a new group of creators of documentation, perhaps predominantly social scientists and humanists, taking the front lines in dealing with the “Age of Algorithms,” with their materials then destined for our memory organizations to be cared for into the future.
The Impact of Public Health Expenditure on Economic Development – Evidence from Prefecture-Level Panel Data of Shandong Province
Authors: Li Lin , Wu Maoguo , Wu Zhenyu
Published: December 2017

Public health expenditure is an indispensable part of social economy. The public has always paid close attention to public health expenditure. In order to study the quantitative relation between public health expenditure and social economic development, this paper investigates prefecture-level cities in Shandong Province, due to the unique characteristics of Shandong Province. Making theoretical and empirical contributions, this paper augments the Cobb-Douglas production function with public health expenditure and empirically analyzes economic development of prefecture- level cities in Shandong Province. A panel data set is established, followed by multivariate regression analysis. Empirical results find that public health expenditure per capita and coverage of medical insurance can significantly promote social economic development. However, the expansion and growth of the number of health institutions does not necessarily promote economic development. Instead, it may even hold back economic development by causing personnel redundancy and waste of resources. If the government transfers its investment focus from the scale and the speed of development of medical services to their fairness and efficiency, public health expenditure may vastly improve both public health and economic development.