bluuebunny/crossref_metadata_2025 huggingface dataset:
AC-CBS-Based Partitioned Semi-Implicit Coupling Algorithm for Fluid-Structure Interaction Using Stabilized Second-Order Pressure Scheme
Authors: He Tao , Zhang Kai , Wang Tong
Published: March 2017

We analyze in this paper the pressure splitting scheme of a partitioned semi-implicit coupling algorithm for fluid-structure interaction (FSI) simulation. The semi-implicit coupling algorithm is developed on the ground of the artificial compressibility characteristic-based split (AC-CBS) scheme that serves not only for the fluid subsystem but also for the global FSI system. As the dual-time stepping procedure recommended for quasi-incompressible flows is incorporated into the implicit coupling stage, the fluctuating pressure may be unusually susceptible to the AC coefficient. Moreover, it is not trivial to devise an optimal AC formulation for pressure estimation. Instead, we consider a stabilized second-order pressure splitting scheme in the AC-CBS-based partitioned semi-implicit coupling algorithm. Computer simulation of a benchmark FSI experiment demonstrates that good agreement is exposed between the available and present data.
A Comparison of Fourier Spectral Iterative Perturbation Method and Finite Element Method in Solving Phase-Field Equilibrium Equations
Authors: Song Pengcheng , Yang Tiannan , Ji Yanzhou , Wang Zhuo , Yang Zhigang , Chen Longqing , Chen Lei
Published: March 2017

This paper systematically compares the numerical implementation and computational cost between the Fourier spectral iterative perturbation method (FSIPM) and the finite element method (FEM) in solving partial differential equilibrium equations with inhomogeneous material coefficients and eigen-fields (e.g., stress-free strain and spontaneous electric polarization) involved in phase-field models. Four benchmark numerical examples, including inhomogeneous elastic, electrostatic, and steady-state heat conduction problems demonstrate that (1) the FSIPM rigorously requires uniform hexahedral (3D) and quadrilateral (2D) mesh and periodic boundary conditions for numerical implementation while the FEM permits arbitrary mesh and boundary conditions; (2) the FSIPM solutions are comparable to their FEM counterparts, and both of them agree with the analytic solutions, (3) the FSIPM is much faster in solving equilibrium equations than the FEM to achieve the accurate solutions, thus exhibiting a greater potential for large-scale 3D computations.
Поворот системы координат и дифференцирование интегралов по базисам, инвариантным относительно сдвига
Authors: Oniani Giorgi Giglaevich , Chubinidze Kakha Alegovich
Published: March 2017

Изучается зависимость дифференциальных свойств неопределенного интеграла от поворота системы координат (т.е. от преобразования переменной, которое является поворотом вокруг начала координат), в частности для общих дифференциальных базисов изучается задача Зигмунда о возможности исправления произвольной суммируемой функции с помощью поворота с точки зрения достижения дифференцируемости ее интеграла, а также вопрос об инвариантности свойства дифференцируемости интеграла относительно поворотов. Из полученных результатов вытекают отрицательные решения вышеотмеченных вопросов для базисов довольно общего вида.
Библиография: 19 названий.
Простые конечномерные правоальтернативные унитальные супералгебры с сильно ассоциативной четной частью
Authors: Pchelintsev Sergey Valentinovich , Shashkov Oleg Vladimirovich
Published: March 2017

Доказано, что четная часть простой конечномерной правоальтернативной унитальной супералгебры над полем характеристики 0 полупроста при условии ее сильной ассоциативности.
Библиография: 13 названий.
Travelers' Diarrhea and Other Gastrointestinal Symptoms Among Boston-Area International Travelers
Authors: Stoney Rhett J. , Han Pauline V. , Barnett Elizabeth D. , Wilson Mary E. , Jentes Emily S. , Benoit Christine M. , MacLeod William B. , Hamer Davidson H. , Chen Lin H.
Published: March 2017

This prospective cohort study describes travelers' diarrhea (TD) and non-TD gastrointestinal (GI) symptoms among international travelers from the Boston area, the association of TD with traveler characteristics and dietary practices, use of prescribed antidiarrheal medications, and the impact of TD and non-TD GI symptoms on planned activities during and after travel. We included adults who received a pre-travel consultation at three Boston-area travel clinics and who completed a three-part survey: pre-travel, during travel, and post-travel (2–4 weeks after return). TD was defined as self-reported diarrhea with or without nausea/vomiting, abdominal pain, or fever. Demographic and travel characteristics were evaluated by χ2 test for categorical and Wilcoxon rank-sum test for continuous variables. Analysis of dietary practices used logistic generalized estimating equation models or logistic regression models. Of 628 travelers, 208 (33%) experienced TD and 45 (7%) experienced non-TD GI symptoms. Of 208 with TD, 128 (64%), 71 (36%), and 123 (62%) were prescribed ciprofloxacin, azithromycin, and/or loperamide before travel, respectively. Thirty-nine (36%) of 108 took ciprofloxacin, 20 (38%) of 55 took azithromycin, and 28 (28%) of 99 took loperamide during travel. Of 172 with TD during travel, 24% stopped planned activities, and 2% were hospitalized. Of 31 with non-TD GI symptoms during travel, six (13%) stopped planned activities. International travelers continue to experience diarrhea and other GI symptoms, resulting in disruption of planned activities and healthcare visits for some. Although these illnesses resulted in interruption of travel plans, a relatively small proportion took prescribed antibiotics.
Multiplex Serologic Assessment of Schistosomiasis in Western Kenya: Antibody Responses in Preschool Aged Children as a Measure of Reduced Transmission
Authors: Won Kimberly Y. , Kanyi Henry M. , Mwende Faith M. , Wiegand Ryan E. , Goodhew E. Brook , Priest Jeffrey W. , Lee Yeuk-Mui , Njenga Sammy M. , Secor W. Evan , Lammie Patrick J. , Odiere Maurice R.
Published: March 2017

Currently, impact of schistosomiasis control programs in Schistosoma mansoni–endemic areas is monitored primarily by assessment of parasitologic indicators only. Our study was conducted to evaluate the use of antibody responses as a way to measure the impact of schistosomiasis control programs. A total of 3,612 serum samples collected at three time points from children 1–5 years of age were tested for antibody responses to two schistosome antigens (soluble egg antigen [SEA] and Sm25) by multiplex bead assay. The overall prevalence of antibody responses to SEA was high at baseline (50.0%). After one round of mass drug administration (MDA), there was minimal change in odds of SEA positivity (odds ratio [OR] = 1.02, confidence interval [CI] = 0.79–1.32, P = 0.89). However, after two rounds of treatment, there was a slight decrease in odds of SEA positivity (OR = 0.80, CI = 0.63–1.02, P = 0.08). In contrast to the SEA results, prevalence of antibody responses to Sm25 was lowest at baseline (14.1%) and higher in years 2 (19.8%) and 3 (18.4%). After one round of MDA, odds of Sm25 positivity increased significantly (OR = 1.51, CI = 1.14–2.02, P = 0.005) and remained significantly higher than baseline after two rounds of MDA (OR = 1.37, CI = 1.07–1.76, P = 0.01). There was a significant decrease in the proportion of 1-year-olds with positive SEA responses from 33.1% in year 1 to 13.2% in year 3 and a corresponding decrease in the odds (OR = 3.25, CI = 1.75–6.08, P < 0.001). These results provide preliminary evidence that schistosomiasis program impact can be monitored using serologic responses.
Risk Factors for Household Transmission of Vibrio cholerae in Dhaka, Bangladesh (CHoBI7 Trial)
Authors: Burrowes Vanessa , Perin Jamie , Monira Shirajum , Sack David A. , Rashid Mahamud-ur , Mahamud Toslim , Rahman Zillur , Mustafiz Munshi , Bhuyian Sazzadul I. , Begum Farzana , Zohura Fatema , Biswas Shwapon , Parvin Tahmina , Hasan Tasdik , Zhang Xiaotong , Sack Bradley R. , Saif-Ur-Rahman K. M. , Alam Munirul , George Christine Marie
Published: March 2017

Household contacts of cholera patients are at a 100 times higher risk of a Vibrio cholerae infection than the general population. To examine risk factors for V. cholerae infections and investigate intervention strategies among this population, we followed household contacts of cholera patients for the 1-week high-risk period after the index patient obtained care. This study was nested within a randomized controlled trial of the Cholera-Hospital-Based-Intervention-for-7-days (CHoBI7), a handwashing with soap and water treatment intervention in Dhaka, Bangladesh. Rectal swab results were available from 320 household contacts of cholera patients at five time points over a 1-week period. Fecal and water samples were analyzed for V. cholerae by bacterial culture. All analyses were stratified by study arm. Within the intervention arm, stored household drinking water with a median free chlorine concentration below 0.5 mg/L was associated with a three times higher odds of a cholera infection (odds ratio [OR]: 3.0; 95% confidence interval [CI]: 1.32, 6.63). In the control arm, having V. cholerae in stored water was associated with a significantly higher odds of a symptomatic cholera infection (OR: 8.66; 95% CI: 2.11, 35.48). No association was found between observed handwashing with soap at food and stool-related events and V. cholerae infections. Stored household drinking water with detectable V. cholerae and chlorine concentrations below the World Health Organization guideline were found to be important risk factors for cholera infection among household contacts of cholera patients. These findings emphasize the need for water treatment interventions targeting this high risk population.
Bungarus multicinctus multicinctus Snakebite in Taiwan
Authors: Mao Yan-Chiao , Liu Po-Yu , Chiang Liao-Chun , Liao Shu-Chen , Su Hung-Yuan , Hsieh Szu-Yin , Yang Chen-Chang
Published: March 2017

Although specific antivenom is available in Taiwan, respiratory failure and general pain frequently accompany Bungarus multicinctus envenomation and there have been few reports on the management of B. multicinctus envenomation. We retrospectively analyzed 44 cases of B. multicinctus bite admitted to Taichung Veterans General Hospital (VGH) or to Taipei VGH. Demographic data, treatment, and outcome of patients with and without respiratory failure were compared. In this study, 20.5% patients had bites without noticeable signs or symptoms of significant envenoming, 27.3% developed respiratory failure, and 27.3% experienced general pain. Bivalent specific antivenom for B. multicinctus and N. atra was administered in all envenomed cases. Respiratory failure occurred 1.5–6.5 hours post-bite and general pain occurred 1–12 hours post-bite. Specific antivenom for B. multicinctus and N. atra at the recommended dose (i.e., 2–4 vials) might not effectively prevent respiratory failure and pain. Respiratory failure, general pain, and autonomic effects after B. multicinctus bite were probably caused, at least partly, by β-bungarotoxin. Although general weakness, ptosis, dysarthria, and dilated pupils were significantly associated with respiratory failure, their predictive value could not be accurately determined in such a retrospective study. Due to the rapid onset of respiratory failure, every suspected envenomed case thus should be closely monitored in the first few hours. We recommend the initial administration of four vials of antivenom in all envenomation cases, and a subsequent four vials be considered if the patient's condition is deteriorating. Prospective evaluation of the antivenom dosing regimen is urgently needed to improve B. multicinctus envenomation treatment.
Symptomatic Falciparum Malaria After Living in a Nonendemic Area for 10 Years: Recrudescence or Indigenous Transmission?
Authors: Salas-Coronas Joaquín , Soriano-Pérez Manuel Jesús , Lozano-Serrano Ana B. , Pérez-Moyano Rosario , Porrino-Herrera Carmen , Cabezas-Fernández María Teresa
Published: March 2017

We report the case of a patient from Mali who, after 10 years of living in Spain, presented with symptomatic Plasmodium falciparum malaria without having visited an endemic area during that time. We cannot completely rule out the possibility of indigenous transmission, but this case most likely represents recrudescence of an infection acquired over 10 years earlier.
Izobraževanje v muzeju: animiranje za kulturne spremembe. Pogovarjali smo se s Sonjo Kogej Rus
Authors: Findeisen Dušana
Published: March 2017

Muzeje razumemo kot ustanove, ki poleg svoje osnovne dejavnosti tudi izobražujejo. Nekateri avtorji pa menijo, da je izobraževanje in učenje celo ena od osrednjih nalog muzejev. Z izobraževanjem nagovarjajo različne ciljne skupine, saj so programi zelo različni. Gibljejo se od radikalne muzeologije in muzejskega aktivizma s subverzivnim izobraževanjem do participativnega učenja in razmišljanja o individualnih spominih, doživetjih, čustvih. Veliko izkušenj z izobraževanjem imajo v Slovenskem etnografskem muzeju,3 kjer je Sonja Kogej Rus, po izobrazbi etnologinja in zgodovinarka, kustosinja pedagoginja (od 1993) in muzejska svetovalka (od 2006) ter vodja Oddelka za muzejsko pedagogiko in andragogiko. V tem muzeju že 25 let opravlja pedagoško in andragoško delo, snuje izobraževalne programe in projekte, razstave ter predvsem odkriva zmeraj nove poti.
Monika Govekar-Okoliš in Renata Kranjčec MENTORSTVO V PRAKTIČNEM USPOSABLJANJU V DELOVNIH ORGANIZACIJAH, Ljubljana, Znanstvena založba Filozofske fakultete, 2016
Authors: Podgornik Vesna
Published: March 2017

Bolonjska reforma je prinesla mnogo izzivov, med njimi tudi vprašanje o prenovi praktičnega usposabljanja. Monografija je izvirno delo uveljavljenih avtoric, ki se ukvarjata z raziskovanjem področja mentorstva. Delo obravnava področje mentorstva študentom v praktičnem usposabljanju v delovnih organizacijah po uvedbi bolonjskih študijskih programov. Pomembno je, ker mentorjem praktičnega usposabljanja ponuja temeljna znanja, ki jih ti potrebujejo za kakovostno mentorstvo. Monografija je sestavljena iz teoretičnega in empiričnega dela.
Pomen dejavnega državljanstva in državljanske vzgoje v času migracij in begunske krize v Evropi
Authors: Mikulec Borut
Published: March 2017

V prispevku obravnavamo koncipiranje državljanske vzgoje in dejavnega državljanstva v izobraževanju odraslih v vse bolj raznoliki in pluralni evropski družbi, ki se sooča z množičnim prihodom beguncev in migrantov. V izhodišče razprave postavljamo dva koncepta državljanske vzgoje: »državljanstvo kot status« in »državljanstvo kot prakso«. Pri opredelitvi prvega izhajamo iz Habermasovega pojmovanja demokracije in javne sfere ter pokažemo, da je državljanska vzgoja v integracijskih izobraževalnih programih povezana predvsem s prilagoditvijo prišlekov obstoječemu liberalnodemokratskemu družbenemu redu, torej z njeno socializacijsko funkcijo. V nasprotju s to konceptualizacijo državljanske vzgoje ter opirajoč se na pojmovanje demokracije in političnega, kot sta ga razvila Mouffejeva in Rancière, dokazujemo tezo, da sta državljanska vzgoja in dejavno državljanstvo bistveno povezana s prakticiranjem demokracije, torej z njeno subjektivizacijsko funkcijo, v kateri lahko vsi potencialni člani neke skupnosti, ne glede na njihov status, aktivno participirajo v javni sferi, govorijo kot njeni enakovredni člani ter se tako učijo demokratičnih praks.
Potrebe po magistrskem študiju babištva v Sloveniji
Authors: Mivšek Ana Polona , Škodič Zakšek Teja , Petročnik Petra , Jug Došler Anita
Published: March 2017

Bolonjska reforma je v slovensko visoko šolstvo prinesla številne spremembe, ki pri vseh študijskih programih niso povsem enoznačne in enosmerne. Študijski program babištva se v Sloveniji izvaja izključno na prvi stopnji, podiplomskega študija za zdaj ni. V raziskavi, ki je temeljila na empiričnem anketnem raziskovalnem pristopu in je bila zasnovana na kvantitativni raziskovalni paradigmi, nas je zanimal interes babic s srednjo izobrazbo za vpis v zdajšnji visokošolski strokovni študijski program babištva prve stopnje ter interes diplomantov in študentov za vpis na morebitni podiplomski magistrski študijski program babištva. Rezultati so pokazali, da je interes anketirancev veliko večji za vpis na podiplomski magistrski študijski program babištva, medtem ko je zanimanje za zdajšnji dodiplomski študijski program babištva nekoliko manjše. Smiselno bi bilo omogočiti nadgraditev kariernih poti diplomantov babištva z možnostjo podiplomskega študija. Ta težnja je upravičena tudi zaradi zahtevnosti babiške dejavnosti in jo potrjujejo tuje usmeritve.
Sesquicentennial of the birth of Edmund Faustinus Biernacki, a discoverer of the erythrocyte sedimentation rate
Authors: J. Kucharz Eugeniusz
Published: March 2017

Edmund Faustinus Biernacki (1866–1911) was a Polish physician and philosopher of medicine. He described erythrocyte sedimentation, designed equipment to measure the erythrocyte sedimentation rate, and applied it to clinical practice. His contribution to the development of one of the most commonly used medical laboratory tests is forgotten, and the test is attributed to other scientists.
Nail psoriasis – what a rheumatologist should know about
Authors: Nieradko-Iwanicka Barbara
Published: March 2017

Psoriasis is a chronic recurrent inflammatory skin disease with prevalence of 1–3%. Nail psoriasis affects 10–90% of patients with plaque psoriasis.

The aim of the article is to review the literature for the correlation between nail psoriasis and psoriatic arthritis (PsA) to provide rheumatologists a short review on features of nail psoriasis, methods of their assessment and possible clinical repercussions.

The PubMed database was searched using the key words ‘nail psoriasis’ and ‘psoriatic arthritis’.

Psoriasis involving the nail matrix shows up as changes such as pitting, Beau lines, leukonychia, red spots in the lunula, or nail plate crumbling. Nail bed psoriasis manifests as onycholysis, oil drops (or salmon patches), dyschromia, splinter hemorrhages, or subungual hyperkeratosis. Nail psoriasis and psoriatic lesions in the gluteal cleft and on the scalp usually accompany PsA, especially in adult men.
Palpable mass of the neck in the course of Takayasu arteritis
Authors: Andrzejewska Karolina , Starba Aleksandra , Misterska-Skóra Maria , Wiland Piotr , Guziński Maciej
Published: March 2017

Takayasu arteritis is a rare, idiopathic inflammatory disease of the aorta and its major branches, usually affecting young women of Asian descent. In the course of the disease stenosis, occlusions as well as dilatations and aneurysms of vessels occur. Because of many possible localizations of pathological changes, the symptoms have a wide range, but the most common are a weak pulse or its absence on the brachial artery and a difference in systolic pressure above 10 mm Hg between the upper extremities. Here we present a case report of a young woman with Takayasu arteritis, who presented a palpable mass in the back of her neck, significantly diminished after treatment with glucocorticoids.
Evidence for renoxification in the tropical marine boundary layer
Authors: Reed Chris , Evans Mathew J. , Crilley Leigh R. , Bloss William J. , Sherwen Tomás , Read Katie A. , Lee James D. , Carpenter Lucy J.
Published: March 2017

Abstract. We present 2 years of NOx observations from the Cape Verde Atmospheric Observatory located in the tropical Atlantic boundary layer. We find that NOx mixing ratios peak around solar noon (at 20–30 pptV depending on season), which is counter to box model simulations that show a midday minimum due to OH conversion of NO2 to HNO3. Production of NOx via decomposition of organic nitrogen species and the photolysis of HNO3 appear insufficient to provide the observed noontime maximum. A rapid photolysis of nitrate aerosol to produce HONO and NO2, however, is able to simulate the observed diurnal cycle. This would make it the dominant source of NOx at this remote marine boundary layer site, overturning the previous paradigm according to which the transport of organic nitrogen species, such as PAN, is the dominant source. We show that observed mixing ratios (November–December 2015) of HONO at Cape Verde (∼ 3.5 pptV peak at solar noon) are consistent with this route for NOx production. Reactions between the nitrate radical and halogen hydroxides which have been postulated in the literature appear to improve the box model simulation of NOx. This rapid conversion of aerosol phase nitrate to NOx changes our perspective of the NOx cycling chemistry in the tropical marine boundary layer, suggesting a more chemically complex environment than previously thought.
Surface ozone at Nam Co (4730 m a.s.l.) in the inland Tibetan Plateau:
variation, synthesis comparison and regional representativeness
Authors: Yin Xiufeng , Kang Shichang , de Foy Benjamin , Cong Zhiyuan , Luo Jiali , Zhang Lang , Ma Yaoming , Zhang Guoshuai , Rupakheti Dipesh , Zhang Qianggong
Published: March 2017

Abstract. Ozone is an important pollutant and greenhouse gas, and tropospheric ozone variations are generally associated with both natural and anthropogenic processes. As one of the most pristine and inaccessible regions in the world, the Tibetan Plateau has been considered as an ideal region for studying processes of the background atmosphere. Due to the vast area of the Tibetan Plateau, sites in the southern, northern and central regions exhibit different patterns of variation in surface ozone. Here, we present long-term measurements for ~ 5 years (January 2011 to October 2015) of surface ozone mixing ratios at Nam Co Station, which is a regional background site in the inland Tibetan Plateau. An average surface ozone mixing ratio of 47.6 ± 11.6 ppb was recorded, and a large annual cycle was observed with maximum ozone mixing ratios in the spring and minimum ratios during the winter. The diurnal cycle is characterized by a minimum in the early morning and a maximum in the late afternoon. Nam Co Station represents a background region where surface ozone receives negligible local anthropogenic emissions. Surface ozone at Nam Co Station is mainly dominated by natural processes involving photochemical reactions and potential local vertical mixing. Model results indicate that the study site is affected by the surrounding areas in different seasons and that air masses from the northern Tibetan Plateau lead to increased ozone levels in the summer. In contrast to the surface ozone levels at the edges of the Tibetan Plateau, those at Nam Co Station are less affected by stratospheric intrusions and human activities which makes Nam Co Station representative of vast background areas in the central Tibetan Plateau. By comparing measurements at Nam Co Station with those from other sites in the Tibetan Plateau and beyond, we aim to expand the understanding of ozone cycles and transport processes over the Tibetan Plateau. This work may provide a reference for model simulations in the future.
Mixing times of organic molecules within secondary organic aerosol
particles: a global planetary boundary layer perspective
Authors: Maclean Adrian M. , Butenhoff Christopher L. , Grayson James W. , Barsanti Kelley , Jimenez Jose L. , Bertram Allan K.
Published: March 2017

Abstract. When simulating the formation and life cycle of secondary organic aerosol (SOA) with chemical transport models, it is often assumed that organic molecules are well mixed within SOA particles on the time scale of 1 h. While this assumption has been debated vigorously in the literature, the issue remains unresolved in part due to a lack of information on the mixing times within SOA particles as a function of both temperature and relative humidity. Using laboratory data, meteorological fields and a chemical transport model, we determine how often mixing times are
Calibration and evaluation of CCD spectroradiometers for airborne
measurements of spectral actinic flux densities
Authors: Bohn Birger , Lohse Insa
Published: March 2017

Abstract. The properties and performance of CCD array spectroradiometers for the measurement of atmospheric spectral actinic flux densities and photolysis frequencies were investigated. These instruments are widely used in atmospheric research and are suitable for aircraft applications because of high time resolutions and high sensitivities in the UV range. The laboratory characterization included instrument-specific properties like wavelength accuracy, dark signals, dark noise and signal-to-noise ratios. Spectral sensitivities were derived from measurements with spectral irradiance standards. The calibration procedure is described in detail and a straightforward method to minimize the influence of stray light on spectral sensitivities is introduced. Detection limits around 1×1010cm−2 s−1 nm−1 were derived for spectral actinic flux densities in a 300 nm range (1 s integration time). As a prerequisite for the determination of stray light under field conditions, atmospheric cutoff wavelengths were defined using radiative transfer calculations as a function of solar zenith angles and ozone columns. The recommended analysis of field data relies on these cutoff wavelengths and is also described in detail taking data from a research flight as an example. An evaluation of field data was performed by ground-based comparisons with a double-monochromator reference spectroradiometer. Spectral actinic flux densities were compared as well as photolysis frequencies j(NO2) and j(O1D), representing UV-A and UV-B ranges, respectively. The spectra expectedly revealed an increased daytime level of residual noise below atmospheric cutoff wavelengths that is caused by stray light. The influence of instrument noise and stray light induced noise was found to be insignificant for j(NO2) and rather limited for j(O1D), resulting in estimated detection limits of 5×10−7 s−1 and 1×10−7 s−1, respectively. For j(O1D) the detection limit could be further reduced by setting spectral actinic flux densities below cutoff wavelengths to zero. The accuracies of photolysis frequencies were determined from linear regressions with reference instrument data. The agreement was typically within ±5 %. Optical receiver aspects were widely excluded in this work and will be treated in a separate paper in particular with regard to airborne applications. Overall, the investigated instruments are clearly suitable for high quality photolysis frequency measurements with high time resolution as required for airborne applications. An example of data from a flight on the research aircraft HALO is presented.
Simulating natural carbon sequestration in the Southern Ocean: on uncertainties associated with eddy parameterizations and iron deposition
Authors: Dietze Heiner , Getzlaff Julia , Löptien Ulrike
Published: March 2017

Abstract. The Southern Ocean is a major sink for anthropogenic carbon. Yet, there is no quantitative consensus about how this sink will change when surface winds increase (as they are anticipated to do). Among the tools employed to quantify carbon uptake are global coupled ocean-circulation–biogeochemical models. Because of computational limitations these models still fail to resolve potentially important spatial scales. Instead, processes on these scales are parameterized. There is concern that deficiencies in these so-called eddy parameterizations might imprint incorrect sensitivities of projected oceanic carbon uptake. Here, we compare natural carbon uptake in the Southern Ocean simulated with contemporary eddy parameterizations. We find that very differing parameterizations yield surprisingly similar oceanic carbon in response to strengthening winds. In contrast, we find (in an additional simulation) that the carbon uptake does differ substantially when the supply of bioavailable iron is altered within its envelope of uncertainty. We conclude that a more comprehensive understanding of bioavailable iron dynamics will substantially reduce the uncertainty of model-based projections of oceanic carbon uptake.
The effects of environment on Arctica islandica shell formation and architecture
Authors: Milano Stefania , Nehrke Gernot , Wanamaker Jr. Alan D. , Ballesta-Artero Irene , Brey Thomas , Schöne Bernd R.
Published: March 2017

Abstract. Mollusks record valuable information in their hard parts that reflect ambient environmental conditions. For this reason, shells can serve as excellent archives to reconstruct past climate and environmental variability. However, animal physiology and biomineralization, which are often poorly understood, can make the decoding of environmental signals a challenging task. Many of the routinely used shell-based proxies are sensitive to multiple different environmental and physiological variables. Therefore, the identification and interpretation of individual environmental signals (e.g., water temperature) often is particularly difficult. Additional proxies not influenced by multiple environmental variables or animal physiology would be a great asset in the field of paleoclimatology. The aim of this study is to investigate the potential use of structural properties of Arctica islandica shells as an environmental proxy. A total of 11 specimens were analyzed to study if changes of the microstructural organization of this marine bivalve are related to environmental conditions. In order to limit the interference of multiple parameters, the samples were cultured under controlled conditions. Three specimens presented here were grown at two different water temperatures (10 and 15 °C) for multiple weeks and exposed only to ambient food conditions. An additional eight specimens were reared under three different dietary regimes. Shell material was analyzed with two techniques; (1) confocal Raman microscopy (CRM) was used to quantify changes of the orientation of microstructural units and pigment distribution, and (2) scanning electron microscopy (SEM) was used to detect changes in microstructural organization. Our results indicate that A. islandica microstructure is not sensitive to changes in the food source and, likely, shell pigment are not altered by diet. However, seawater temperature had a statistically significant effect on the orientation of the biomineral. Although additional work is required, the results presented here suggest that the crystallographic orientation of biomineral units of A. islandica may serve as an alternative and independent proxy for seawater temperature.
Seasonal and interannual dynamics of soil microbial biomass and available nitrogen in an alpine meadow in the eastern part of Qinghai-Tibet Plateau, China
Authors: Xu Bo , Wang Jinniu , Wu Ning , Wu Yan , Shi Fusun
Published: March 2017

Abstract. Soil microbial activity occurs seasonally in frozen alpine soils during cold seasons and plays a crucial role in available N pool accumulation in soil. The intra- and interannual patterns of microbial and nutrient dynamics reflect the influences of changing weather factors, and thus provide important insights into the biogeochemical cycles and ecological functions of ecosystems. We documented seasonal and interannual dynamics of soil microbial and available N in an alpine meadow in the eastern part of Qinghai-Tibet Plateau, China between April 2011 and October 2013. Soil samples were collected in the middle of each month and were analyzed for water content, microbial biomass C (MBC) and N, dissolved organic C and N, and inorganic N; soil microbial community compositions were measured by the dilution-plate method. Fungi and actinomycetes dominated the microbial community during the non-growing seasons, and the number of bacteria increased considerably during the early growing seasons. Consistently increasing trends of MBC and available N pools were observed during the non-growing seasons. MBC sharply declined during soil thaw and was accompanied by a peak of available N pool. Induced by soil temperatures, significant shifts in the structure and functions of microbial communities were found during the winter-spring transition and largely contributed to microbial reduction. Divergent seasonal dynamics of different N forms showed a complementary nutrient supply pattern during the growing season. Similar interannual dynamics were observed between microbial biomass and available N pools, and soil temperature and water condition were the primary environmental factors driving these year-to-year fluctuations. Under the background of changing climate, the seasonal soil microbial activity and nutrient supply patterns will be further changed, having important implications to the productivity and biodiversity of alpine ecosystems.
Atlantic Water advection vs glacier dynamics in northern Spitsbergen since early deglaciation
Authors: Bartels Martin , Titschack Jürgen , Fahl Kirsten , Stein Rüdiger , Seidenkrantz Marit-Solveig , Hillaire-Marcel Claude , Hebbeln Dierk
Published: March 2017

Abstract. Atlantic Water (AW) advection plays an important role for climatic, oceanographic and environmental conditions in the eastern Arctic. Situated along the only deep connection between the Atlantic and the Arctic Ocean, the Svalbard Archipelago is an ideal location to reconstruct the past AW advection history and document its linkage with local glacier dynamics, as illustrated in the present study of a sedimentary record from Woodfjorden (northern Spitsbergen) spanning the last ~ 15 500 years. Sedimentological, micropalaeontological and geochemical analyses were used to reconstruct changes in marine environmental conditions, sea-ice cover and glacier activity. Data illustrate a partial breakup of the Svalbard–Barents–Sea Ice Sheet from Heinrich Stadial 1 onwards (until ~ 14.6 ka BP). During the Bølling-Allerød (~ 14.6–12.7 ka BP), AW penetrated as a bottom water mass into the fjord system and contributed significantly to the destabilisation of local glaciers. During the Younger Dryas (~ 12.7–11.7 ka BP), it intruded into intermediate waters while evidence for a glacier advance is lacking. A short-term deepening of the halocline occurred at the very end of this interval. During the early Holocene (~ 11.7–7.8 ka BP), mild conditions led to glacier retreat, a reduced sea-ice cover and increasing sea surface temperatures, with a brief interruption during the Preboreal Oscillation (~ 11.1–10.8 ka BP). During the late Holocene (~ 1.8–0.4 ka BP), a slightly reduced AW inflow and lower sea surface temperatures compared to the early Holocene are reconstructed. Glaciers, which previously retreated to the shallower inner parts of the Woodfjorden system, likely advanced during the late Holocene. In particular, as topographic control in concert with the reduced summer insolation partly decoupled glacier dynamics from AW advection during this recent interval.
Automated observatory in Antarctica: real-time data transfer on
constrained networks in practice
Authors: Bracke Stephan , Gonsette Alexandre , Rasson Jean , Poncelet Antoine , Hendrickx Olivier
Published: March 2017

Abstract. In 2013 the scientists from the geophysical centre at Dourbes started a project to install a fully automated magnetic observatory in Antarctica. This isolated place comes with specific requirements: unmanned station during six months, low temperatures with extreme values up to –50°, minimize power consumption, satellite bandwidth limited to 56 Kbit/sec. The ultimate aim is to collect real-time magnetic data every second in Belgium: vector data from a lemi-25, absolute F measurements from a gems proton magnetometer and absolute magnetic inclination and declination measurements (approximately 5 times a day) with an automated DI-flux. To achieve real-time data transfer with traditional file transfer protocols (for instance sftp, mail, rsync), you fight against their limitations in terms of real-time. After evaluation of pro and cons of the on that moment available real-time internet of things (IoT) protocols and seismic software solutions known to UGCS, we chose to use message queuing telemetry transport (MQTT) and receive the one second data with a negligible latency cost and no loss of data. Each individual instrument sends his data towards Belgium immediately after capturing it and arrives at approximately 300 milliseconds after sending which corresponds with the normal satellite latency.
Evaluation of JULES-crop performance against site observations of irrigated maize from Mead, Nebraska
Authors: Williams Karina , Gornall Jemma , Harper Anna , Wiltshire Andy , Hemming Debbie , Quaife Tristan , Arkebauer Tim , Scoby David
Published: March 2017

Abstract. The JULES-crop model (Osborne et al., 2015) is a parametrisation of crops within the Joint UK Land Environment Simulator (JULES), which aims to simulate both the impact of weather and climate on crop productivity and the impact of croplands on weather and climate. In this evaluation paper, observations of maize at three FLUXNET sites in Nebraska (US-Ne1, US-Ne2 and US-Ne3) are used to test model assumptions and make appropriate input parameter choices. JULES runs are performed for the irrigated sites (US-Ne1 and US-Ne2) both with the crop model switched off (prescribing leaf area index (LAI) and canopy height) and with the crop model switched on. These are compared against GPP and carbon pool FLUXNET observations. We use the results to point to future priorities for model development and describe how our methodology can be adapted to set up model runs for other sites and crop varieties.
FluxnetLSM R package (v1.0): A community tool for
processing FLUXNET data for use in land surface
modelling
Authors: Ukkola Anna M. , Haughton Ned , De Kauwe Martin G. , Abramowitz Gab , Pitman Andy J.
Published: March 2017

Abstract. Flux towers measure ecosystem-scale surface-atmosphere exchanges of energy, carbon dioxide and water vapour. The network of flux towers now encompasses ~ 900 sites, spread across every continent. Consequently, these data have become an essential benchmarking tool for land surface models (LSMs). However, these data as released are not immediately usable for driving, evaluating and benchmarking LSMs. Flux tower data must first be transformed into a LSM-readable file format, a process which involves changing units, screening missing data and varying degrees of additional gap- filling. All of this often leads to an under-utilisation of these data in model benchmarking. To resolve some of these issues, and to help make flux tower measurements more widely used, we present a reproducible, open-source R package that transforms the latest FLUXNET2015 release into community standard NetCDF files that are directly usable by LSMs.
Improving Calibration and Validation of Cosmic-Ray Neutron
Sensors in the Light of Spatial Sensitivity – Theory and Evidence
Authors: Schrön Martin , Köhli Markus , Scheiffele Lena , Iwema Joost , Bogena Heye R. , Lv Ling , Martini Eduardo , Baroni Gabriele , Rosolem Rafael , Weimar Jannis , Mai Juliane , Cuntz Matthias , Rebmann Corinna , Oswald Sascha E. , Dietrich Peter , Schmidt Ulrich , Zacharias Steffen
Published: March 2017

Abstract. In the last years the method of cosmic-ray neutron sensing (CRNS) has gained popularity among soil hydrologists, physicists, and land-surface modelers. The sensor provides continuous soil moisture data, averaged over several hectares and tens of decimeters depth. However, the signal still may contain unidentified features of hydrological processes, and many calibration datasets are often required in order to find reliable relations between neutrons and water dynamics. Recent insights into environmental neutrons accurately described the spatial sensitivity of the sensor and thus allowed to quantify the contribution of individual sample locations to the CRNS signal. Consequently, data points of calibration and validation datasets are suggested to be averaged using a more physically-based weighting approach. In this work, a revised sensitivity function is used to calculate weighted averages of point data. The approach is extensively tested with two calibration and four time series datasets from a variety of sites and conditions. In all cases, the revised averaging method robustly improved the performance of the CRNS product and even helped to reveal otherwise hidden hydrological processes. The presented approach increases the overall accuracy of CRNS products and will have impact on all their applications in agriculture, hydrology, and modeling.
The effect of Three Gorges Dam and rainfall on summer flow risk over Yangtze River Basin
Authors: Su Zhenkuan , Hao Zhenchun , Ho Michelle , Lall Upmanu , Sun Xun , Chen Xi , Yan Longzeng
Published: March 2017

Abstract. As the largest water conservancy project, Three Gorges Dam starts its impoundment in 2003 and henceforth the efficient operation of a multi-purpose dam has aroused a great concern on the effectiveness on flood control and water management over Yangtze River Basin. In this paper, we consider the relationship between rainfall from 136 weather stations and streamflow from 5 hydrological stations including Cuntan, Yichang, Luoshan, Hankou and Datong. Meanwhile, the spatial average rainfall over 21 subbasins was computed. The analysis of the correlation demonstrated that the correlation of spatial average rainfall and streamflow for each station is consistent with that between rainfall by stations and streamflow. Then, two options were selected to develop the linear models, including option a) using rainfall by stations to forecast streamflow and option b) using spatial average rainfall to forecast streamflow. The canonical correlation analysis enabled a large degree of spatially coherent information of rainfall by linear transforms to maximize the correlation of rainfall and streamflow for developing linear models. The model resulting from option b) best fits the observations. Coefficient of determination for each model and statistics such as reduction of error, coefficient of efficiency under cross validation serve as a test of good performance of the model. An analysis of streamflow characteristics across the stations illustrated that the streamflow of Cuntan and Yichang have different modes of variability from that of the rest stations below the dam. The comparison of risk type changes between observations and predictions during the post-dam period showed the dam effectively relieved the risk of upstream while not always played a positive role in risk mitigation of downstream. The spatial and temporal patterns of rainfall anomalies over the whole basin helps to explain how the dam impact the streamflow. Some applications as to possible operational strategies are discussed.
A high-resolution dataset of water fluxes and states for Germany accounting for parametric uncertainty
Authors: Zink Matthias , Kumar Rohini , Cuntz Matthias , Samaniego Luis
Published: March 2017

Abstract. Long-term, high-resolution data about hydrologic fluxes and states are needed for many hydrological applications. Because continuous large-scale observations of such variables are not feasible, hydrologic or land surface models are applied to derive them. This study aims to analyze and provide a consistent high-resolution dataset of land surface variables over Germany, accounting for uncertainties caused by equifinal model parameters. The mesoscale Hydrological Model (mHM) is employed to derive an ensemble (100 members) of evapotranspiration, groundwater recharge, soil moisture, and runoff generated at high spatial and temporal resolutions (4 km and daily, respectively) for the period 1951–2010. The model is cross-evaluated against the observed daily streamflow in 222 basins, which are not used for model calibration. The mean (standard deviation) of the ensemble median Nash–Sutcliffe efficiency estimated for these basins is 0.68 (0.09) for daily streamflow simulations. The modeled evapotranspiration and soil moisture reasonably represent the observations from eddy covariance stations. Our analysis indicates the lowest parametric uncertainty for evapotranspiration, and the largest is observed for groundwater recharge. The uncertainty of the hydrologic variables varies over the course of a year, with the exception of evapotranspiration, which remains almost constant. This study emphasizes the role of accounting for the parametric uncertainty in model-derived hydrological datasets.
Time clustering of wave storms in the Mediterranean Sea
Authors: Besio Giovanni , Briganti Riccardo , Romano Alessandro , Mentaschi Lorenzo , De Girolamo Paolo
Published: March 2017

Abstract. In this contribution we identify storm time clustering in the Mediterranean Sea through a comprehensive analysis of the Allan factor. This parameter is evaluated from a long time series of wave height provided by oceanographic buoy measurements and hindcast reanalysis of the whole basin, spanning the period 1979–2014 and characterized by a horizontal resolution of about 0.1° in longitude and latitude and a temporal sampling of 1 h Mentaschi et al. (2015). The nature of the processes highlighted by the AF and the spatial distribution of the parameter are both investigated. Results reveal that the Allan factor follows different curves at two distinct timescales. The range of timescales between 12 h to 50 days is characterized by a departure from the Poisson distribution. For timescales above 50 days, a cyclic Poisson process is identified. The spatial distribution of the Allan factor reveals that the clustering at smaller timescales is present to the north-west of the Mediterranean, while seasonality is observed across the whole basin. This analysis is believed to be important for assessing the local increased flood and coastal erosion risks due to storm clustering.
Model sensitivity for the prediction of extreme sea level events at a wide and fast-flowing estuary: the case of the Río de la Plata
Authors: Dinapoli Matías G. , Simionato Claudia G. , Moreira Diego
Published: March 2017

Abstract. A parameter sensitivity analysis for a pre-operational 2-D barotropic application of the ROMS_AGRIF ocean model for the forecast of sea surface height (SSH) and currents at the South-Western South Atlantic Continental Shelf with emphasis in the Río de la Plata Estuary is presented. Particularly, the interest is on the simulation of extreme storm surges generated by persistent and strong southeasterly winds (Sudestadas) which produce strong floods. Atmospheric models show deficiencies in the forecast of winds during those events. Therefore, linear and quadratic bottom friction, wind speed and direction, and runoff were considered in the sensitivity analysis. The analysis yields to a hierarchy of the impacts of them on the simulated SSH. The most important, with non-linearity in the model response, is wind speed. It is followed by the quadratic bottom friction and the runoff, which responses are more linear, and present a regional dependence. Runoff has a larger impact than friction in the upper estuary, which decreases downstream. Non-linearity of wind speed is mainly due to the parametrization of the stress tensor, whereas the interaction with the runoff is not relevant in spite of the huge discharge of this particular estuary. This information allows an optimal calibration of the model with a minimum number of simulations.