bluuebunny/crossref_metadata_2025 huggingface dataset:
Knowledge, attitude, and practice of pediatricians regarding pediatric liquid medicaments
Authors: Girish Babu K. L. , Doddamani Geeta Maruti , L.R Kumaraswamy Naik
Published: March 2017

Objective:To assess the knowledge, attitude, and practice of pediatricians regarding pediatric liquid medicaments (PLMs) and its effect on dental health.Materials and Methods: A convenience sample of 103 pediatricians was asked to answer a questionnaire.Results: A total number of 87 pediatricians completed the questionnaires. They considered age and body weight of the child (58%), cost of the medicine (40%), and pharmaceutical company (37%) to be relevant while prescribing. Eighty-eight percent of pediatricians knew that the PLM was sweet in nature. Sixty-seven percent of pediatricians stated that pH of PLM is responsible for deleterious effect on teeth. Seventy-two percent of pediatricians were aware of hidden sugars present in PLM. Only 48% of pediatricians were aware of availability of sugar-free medicine. Seventy percent of pediatricians were of the opinion that sugar-free medicine is not as sweet as sugar-containing medicines and is more expensive (65%).Conclusion: Knowledge, attitude, and practice of pediatricians regarding PLMs and its effect on dental health were not satisfactory.
Effect of cleaning agent, primer application and their combination on the bond strength of a resin cement to two yttrium-tetragonal zirconia polycrystal zirconia ceramics
Authors: Negreiros William Matthew , Ambrosano Glaucia Maria Bovi , Giannini Marcelo
Published: March 2017

Objective: The objective of this study is to evaluate the effect of a cleaning agent and priming on the bond strength (BS) of a resin cement (RC) to zirconia ceramics after 24 h and 1 year of water-storage. Materials and Methods: Fifty-six Katana and 56 ZirCAD zirconia ceramic plates were prepared and each zirconia brand was divided into four groups (n = 14): (1) untreated; (2) treated with Ivoclean cleaning agent; (3) treated with Monobond Plus coupling agent; (4) treated with Ivoclean + Monobond Plus. Cleaning and coupling agents were applied to zirconia following the manufacturers' instructions. The RC was manipulated, inserted into tubes (0.75 mm diameter/1 mm height) that were positioned on the zirconia surfaces and light activated. Specimens were tested after 24 h and 1 year of water storage. A shear load was applied to the base of the RC cylinders (until failure. Data were analyzed by three-way ANOVA and Tukey tests (α = 5%). Results: No significant difference in BS was noted between zirconia ceramics, except when the combination of cleaning and coupling agents was used. This combination increased the BS for Katana zirconia. One year of water storage leads to a decrease in BS for all experimental groups. Conclusion: The combination of cleaning agent and priming can yield higher BS for Katana at 24 h. BS to zirconia ceramics reduced approximately 50% after 1 year.
Comparative clinical efficacy of three toothpastes in the control of supragingival calculus formation
Authors: Kraivaphan Petcharat , Amornchat Cholticha
Published: March 2017

Objectives: The purpose of this double-blind, parallel clinical study was to assess clinical efficacy in supragingival calculus formation reduction using Abhaibhubejhr Herbal Toothpaste compared to Colgate Total and Colgate Cavity Protection toothpastes. Materials and Methods: A total of 150 subjects participated in the pretest phase. All subjects were given oral soft/hard tissue evaluation, calculus examination using Volpe-Manhold calculus, and whole mouth oral prophylaxis. They received noncalculus control fluoride toothpaste and a soft-bristled toothbrush to brush for 1 min two times daily for 8 weeks. After which, subjects were given a test phase oral soft/hard tissue evaluation and calculus examination and were randomized into one of the three toothpaste groups. All subjects in the test phase received a whole mouth oral prophylaxis and were given their assigned toothpaste and a soft-bristled toothbrush to brush for 1 min two times a day for 12 weeks. Thereafter, subjects were assessed for their oral soft/hard tissue and calculus formation. Results: Mean Volpe-Manhold calculus index scores for the Cavity Protection, Abhaibhubejhr, and Total toothpaste groups were 0.78, 0.62, and 0.48, respectively, at the 12-week test phase evaluation. Abhaibhubejhr and Total toothpaste groups show 20.51% and 38.46% significantly less calculus formation than the Cavity Protection toothpaste group (P < 0.05). Total toothpaste group also show 22.58% significantly less calculus formation than the Abhaibhubejhr toothpaste group (P < 0.05). Conclusion: The use of Colgate Total toothpaste over a 12-week period was clinically more effective than either Abhaibhubejhr or Colgate Cavity Protection toothpastes in controlling supragingival calculus formation.
Awareness about the effects of tobacco consumption on oral health and the possibility of smoking behavior among male Saudi schoolchildren
Authors: Ashraf Nazir Muhammad , Almas Khalid
Published: March 2017

Objective: To investigate an association between the awareness about the effects of tobacco consumption on oral health and the likelihood of smoking among male schoolchildren. Materials and Methods: A cross sectional study was conducted using a multistage random sampling technique. The participants (ages 15–19 years) were recruited from male public high schools in Greater Dammam in Saudi Arabia. A pretested questionnaire inquired participants’ awareness about the effects of smoking on oral health. SPSS (Released 2013, IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY: IBM Corp) was used to calculate unadjusted and adjusted odds ratio (OR) and 95% confidence interval (CI). Multiple logistic regression and interaction analyses were performed to identify the factors associated with the probability of smoking behavior among children. Results: More than 69.9% (n = 277) of participants were aware of the adverse effects of tobacco consumption on oral health which included poor oral health, bad taste and breath, periodontal disease, dental caries, oral ulcers, and oral cancers. The odds of smoking were 22%–47% lower among schoolchildren who were aware of the consequences of smoking on oral health than those who were unaware of these complications. The students who believed that smoking can cause oral ulcers and negatively affects oral health had a lower probability of smoking (OR: 0.414; CI: 0.201–0.50) and (OR: 0.433; CI: 0.194–0.965), respectively in comparison with those who thought that smoking had no such negative impacts. Conclusions: Schoolchildren with increased awareness of smoking effects on oral health were less likely to smoke. Educating students about the complications of smoking on oral health should be the part of smoking cessation programs and policies.
Frequency of impacted teeth and categorization of impacted canines: A retrospective radiographic study using orthopantomograms
Authors: Al-Zoubi Hassan , Alharbi Abdulgader Abdullatif , Ferguson Donald J. , Zafar Muhammad Sohail
Published: March 2017

Objective: The objective of this study is to determine the frequency of impacted maxillary canines using seven subtype classification system. For this purpose, impacted maxillary canines have been divided into seven various subtypes. Materials and Methods: This is a descriptive, cross-sectional, and retrospective study conducted using radiographic data of residents of Madinah, Al Munawwarah. Radiographic data of 14,000 patients, who attended College of Dentistry, Taibah University, from January 2011 to February 2015, were screened against the selection criteria for the presence of impacted teeth. The individuals with maxillary impacted canines were matched to maxillary canine impaction. The occurrence of each subtype of impacted canines was calculated. Results: Impacted teeth are more common in the maxilla compared to mandible. The impacted canine represented the highest proportion of all impacted maxillary teeth followed by the second premolars and the central incisors. According to the classification system represented, Type II of canine impaction comprised the highest proportion (51%) while Type IV (0.5%) comprised the lowest frequency. The maxillary canine is the most frequently impacted tooth followed by mandibular canines. Conclusions: Although there are many variations, the majority of impacted canines fall into Type II of the classification of impacted canines.
Complications in implant dentistry
Authors: Hanif Ayesha , Qureshi Saima , Sheikh Zeeshan , Rashid Haroon
Published: March 2017

After tooth loss, an individual may seek tooth replacement so that his/her function and esthetics could be restored. Clinical prosthodontics, during the past decade, has significantly improved and developed according to the advancements in the science and patient's demands and needs. Conventional options in prosthodontics for substituting a missing single tooth include the removable partial denture, partial and full coverage bridgework, and resin-bonded bridgework. Dental implants have gained increasing popularity over the years as they are capable of restoring the function to near normal in both partial and completely edentulous arches. With substantial evidence available, fixed implant-supported prosthesis are fully acknowledged as a reliable treatment option for the replacement of single or multiple missing teeth nowadays. While dental implants are increasingly becoming the choice of replacement for missing teeth, the impediments associated with them are progressively emerging too.
An Ambient Assisted Living Technology Platform for Informal Carers of the Elderly - iCarer
Authors: Lotfi Ahmad , Langensiepen Caroline , Moreno Pedro A. , Gómez Enrique J. , Chernbumroong Saisakul
Published: March 2017

For most families with elderly relatives, care within their own home is by far the most preferred option -both for the elderly and their carers. However, frequently these carers are the partners of the person with long-term care needs, and themselves are elderly and in need of support to cope with the burdens and stress associated with these duties. When it becomes too much for them, they may have to rely on professional care services, or even use residential care for a respite. In order to support the carers as well as the elderly person, an ambient assisted living platform has been developed. The system records information about the activities of daily living using unobtrusive sensors within the home, and allows the carers to record their own wellbeing state. By providing facilities to schedule and monitor the activities of daily care, and providing orientation and advice to improve the care given and their own wellbeing, the system helps to reduce the burden on the informal carers.
Articulating a Patient-Centered Design Space for Cancer Journeys
Authors: Jacobs M.L. , Clawson J. , Mynatt E.D.
Published: March 2017

Cancer journeys, encompassing patients’ cancer experiences through survivorship, are complex and diverse. Individuals must cope with numerous physical and emotional challenges, balancing clinical tasks alongside responsibilities of daily life. Understanding the breadth of factors that contribute to a patient’s cancer experience presents a critical challenge in developing holistic patient-centered technology. To further our understanding of the cancer journey, we conducted focus groups and interviews with 31 breast cancer patients. We present a cancer journey framework depicting the responsibilities, challenges, and personal impacts patients face while transitioning from diagnosis through post-treatment survivorship. Through this work, we aim to aid the development of health tools that consider a patient’s cancer journey and health needs more broadly, supporting patient’s health management alongside the complexities and priorities of daily life.
Germany’s Government-Civil Society Development Cooperation Strategy: the dangers of the middle of the road
Authors: Engel Susan
Published: March 2017

The Organisation for Economic Cooperation and Development (OECD) has been busy since the late 2000s studying the way aid donors manage their relations with development civil society organisations (CSOs). More than studying these relations, they have made some very detailed, managerialist suggestions about how CSOs should be organised and how donor governments should fund and otherwise relate to them. This came out of the debate about aid effectiveness, which was formally aimed at improving both donor and recipient processes. Donors have quietly dropped many of the aspects related to improving their own performance and yet a number have created new interventionist governance frameworks for CSOs. This is the case in Germany, which has a large, vibrant development CSO sector that has traditionally been quite autonomous, even where its received state funding thanks to Germany’s commitment to ‘subsidiarity.’ Yet Germany is otherwise a middle of the road donor and in many ways, these ‘reforms’ are moving its relations with civil society more towards a somewhat more managerialist approach, one that is in fact the norms amongst OECD donors.
Politicized Civil Society in Bangladesh: Case Study Analyses
Authors: Tasnim Farhat
Published: March 2017

Although civil society in Bangladesh is recognized for its vibrant performance in social development, it is often criticized for its inability to ensure good governance and democracy. The aim of this paper is to point out the reasons for this failure of civil society. Through performing case studies upon five civil society organizations representing different sector and level of the civil society, the paper concludes that civil society organizations in Bangladesh are often politicized and co-opted by different political parties. In a typical scenario, civil society can provide a counterbalance or even monitor the state both at the national and local level. However, in Bangladesh, often the civil society organizations have compromised their autonomy and politicized themselves to certain political parties or political block. In such a vulnerable position, civil society can hardly play its expected role to ensure good governance and strengthen democracy.
Emergence of inter-identity alliances in struggles for transformation of the Kenyan constitution
Authors: Mati Jacob Mwathi
Published: March 2017

Struggles for transformation of the Kenyan constitution brought into alliances disparate movements from below, sections of middleclass, and factions of political, economic and religious elites, in challenging the government. The emergence of these alliances presents useful cases for examining the dynamic relationship and politics between these movements, and also for probing social movement theory. Specifically, given the centrality of identity consciousness in movements, how were intrinsic class, religious, gender, generational and ethnic identity interests, contestations and cleavages overcome to enable inter-identity alliances in these struggles? More critically, how relevant are the dominant social movement theories in explaining this phenomenon? Is theoretical straightjacketing useful for analysing movements with such diversity? Drawing from in-depth interviews and existing literature on Kenyan constitutional reform struggles, this paper illustrates how alliances between the different identities and movements were forged to allow for a common struggle. The paper further illustrates that while political opportunity structures explain certain aspects of this phenomenon, framing, civic education and community organising strategies were critical enablers for collective identity formation
Sulfate geoengineering: a review of the factors controlling the needed injection of sulfur dioxide
Authors: Visioni Daniele , Pitari Giovanni , Aquila Valentina
Published: March 2017

Abstract. Sulfate geoengineering has been proposed as an affordable and climate-effective means to temporarily offset the warming produced by the increase of well-mixed greenhouse gases (WMGHGs). This technique would likely have to be applied while and after global intergovernmental measures on emissions of WMGHGs are implemented in order to achieve surface temperature stabilization. The direct radiative effects of sulfur injection in the tropical lower stratosphere can be summarized as increasing shortwave scattering with consequent tropospheric cooling and increasing longwave absorption with stratospheric warming. Indirect radiative effects are related to induced changes in the ozone distribution; stratospheric water vapor abundance,;formation and size of upper-tropospheric cirrus ice particles; and lifetime of long-lived species, namely CH4 in connection with OH changes through several photochemical mechanisms. Direct and indirect effects of sulfate geoengineering both concur to determine the atmospheric response. A review of previous studies on these effects is presented here, with an outline of the important factors that control the amount of sulfur dioxide to be injected in an eventual realization of the experiment. However, we need to take into account that atmospheric models used for these studies have shown a wide range of climate sensitivity and differences in the response to stratospheric volcanic aerosols. In addition, large uncertainties exist in the estimate of some of these aerosol effects.
Lower tropospheric distributions of O3 and aerosol over Raoyang, a rural site in the North China Plain
Authors: Wang Rui , Xu Xiaobin , Jia Shihui , Ma Ruisheng , Ran Liang , Deng Zhaoze , Lin Weili , Wang Ying , Ma Zhiqiang
Published: March 2017

Abstract. The North China Plain (NCP) has become one of the most polluted regions in China, with the rapidly increasing economic growth in the past decades. High concentrations of ambient O3 and aerosol have been observed at urban as well as rural sites in the NCP. Most of the in situ observations of air pollutants have been conducted near the ground so that current knowledge about the vertical distributions of tropospheric O3 and aerosol over the NCP region is still limited. In this study, vertical profiles of O3 and size-resolved aerosol concentrations below 2.5 km were measured in summer 2014 over a rural site in the NCP, using an unmanned aerial vehicle (UAV) equipped with miniature analyzers. In addition, vertical profiles of aerosol scattering property in the lower troposphere and vertical profiles of O3 below 1 km were also observed at the site using a lidar and tethered balloon, respectively. The depths of the mixed layer and residual layer were determined according to the vertical gradients of lidar particle extinction and aerosol number concentration. Average O3 and size-resolved aerosol number concentration in both the mixed and residual layer were obtained from the data observed in seven UAV flights. The results show that during most of the flights the O3 levels above the top of mixed layer were higher than those below. Such a positive gradient in the vertical distribution of O3 makes the residual layer an important source of O3 in the mixed layer, particularly during the morning when the top of mixed layer is rapidly elevated. In contrast to O3, aerosol number concentration was normally higher in the mixed layer than in the residual layer, particularly in the early morning. Aerosol particles were overwhelmingly distributed in the size range  <  1 µm, showing slight differences between the mixed and residual layers. Our measurements confirm that the lower troposphere over the rural area of the NCP is largely impacted by anthropogenic pollutants locally emitted or transported from urban areas. Compared with the historic O3 vertical profiles over Beijing from the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC), a strong increase in O3 can be found at all heights below 2.5 km in the decade from 2004 to 2014, with the largest enhancement of about 41.6 ppb. This indicates that the lower troposphere over the northern part of the NCP has experienced rapidly worsening photochemical pollution. This worsening trend in photochemical pollution deserves more attention in the future.
Temporal characteristics of atmospheric ammonia and nitrogen dioxide over China based on emission data, satellite observations and atmospheric transport modeling since 1980
Authors: Liu Lei , Zhang Xiuying , Xu Wen , Liu Xuejun , Li Yi , Lu Xuehe , Zhang Yuehan , Zhang Wuting
Published: March 2017

Abstract. China is experiencing intense air pollution caused in large part by anthropogenic emissions of reactive nitrogen (Nr). Atmospheric ammonia (NH3) and nitrogen dioxide (NO2) are the most important precursors for Nr compounds (including N2O5, HNO3, HONO and particulate NO3− and NH4+) in the atmosphere. Understanding the changes of NH3 and NO2 has important implications for the regulation of anthropogenic Nr emissions, and is a requirement for assessing the consequence of environmental impacts. We conducted the temporal trend analysis of atmospheric NH3 and NO2 on a national scale since 1980 based on emission data (during 1980–2010), satellite observations (for NH3 since 2008 and for NO2 since 2005) and atmospheric chemistry transport modeling (during 2008–2015). Based on the emission data, during 1980–2010, both significant continuous increasing trend of NH3 and NOx were observed from REAS (Regional Emission inventory in Asia, for NH3 0.17 kg N ha−1 y−2 and for NOx 0.16 kg N ha−1 y−2) and EDGAR (Emissions Database for Global Atmospheric Research, for NH3 0.24 kg N ha−1 y−2 and for NOx 0.17 kg N ha−1 y−2) over China. Based on the satellite data and atmospheric chemistry transport modeling named as the Model for Ozone and Related chemical Tracers, version 4 (MOZART-4), the NO2 columns over China increased significantly (p<0.01) from 2005 to 2011 and then decreased significantly from 2011 to 2015; the satellite-retrieved NH3 columns from 2008 to 2014 had no big changes but increased in 2015 (large increase from satellite IASI, but slight increase from MOZART-4). The decrease in NO2 columns since 2011 may result from more stringent strategies taken to control NOx emissions during the 12th Five-Year-Plan, while no control policy focused on NH3 emissions. Our findings provided an overall insight on the temporal trends of both NO2 and NH3 since 1980 based on emission data, satellite observations and atmospheric transport modeling. These findings can provide a scientific background for policy-makers that are attempting to control atmospheric pollution in China. Moreover, the multivariate data used in this study have implications for estimating long-term Nr deposition datasets to assess its impact on soil, forest, water and greenhouse balance.
Importance of the Saharan Heat Low on the control of the North Atlantic free tropospheric humidity deduced from IASI δD observations
Authors: Lacour Jean-Lionel , Flamant Cyrille , Risi Camille , Clerbaux Cathy , Coheur Pierre-François
Published: March 2017

Abstract. The isotopic composition of water vapour in the North Atlantic free troposphere is investigated with IASI measurements of the D/H ratio (δD) above the ocean. We show that in the vicinity of West Africa, the seasonality of δD is particularly strong (160 ‰), which is related with the installation of the Saharan Heat Low (SHL) during summertime. The SHL indeed largely influences the dynamic in that region by producing deep turbulent mixing layers, yielding a specific water vapor isotopic footprint. The influence of the SHL on the isotopic budget is analysed at various time and space scales and is shown to be large, highlighting the importance of the SHL dynamics on the moistening and the HDO-enrichment of the free troposphere over the North Atlantic. We also report important inter-annual variations of δD above Izana (Canary Islands) that we interpret, using backward trajectory analyses, in terms of the ratio of air-masses coming from the North Atlantic and air-masses coming from the African continent. Finally, we present spatial distributions of δD and humidity above the North Atlantic and we show that the different sources and dehydration pathways controlling the humidity can be disentangled thanks to the added value of δD observations.
Top-down and Bottom-up aerosol-cloud-closure: towards
understanding sources of uncertainty in deriving cloud radiative
flux
Authors: Sanchez Kevin J. , Roberts Greg C. , Calmer Radiance , Nicoll Keri , Hashimshoni Eyal , Rosenfeld Daniel , Ovadnevaite Jurgita , Preissler Jana , Ceburnis Darius , O'Dowd Colin , Russell Lynn M.
Published: March 2017

Abstract. Top-down and bottom-up aerosol-cloud-radiative flux closures were conducted at the Mace Head atmospheric research station in Galway, Ireland in August 2015. This study is part of the BACCHUS (Impact of Biogenic versus Anthropogenic emissions on Clouds and Climate: towards a Holistic UnderStanding) European collaborative project, with the goal of understanding key processes affecting aerosol-cloud-radiative flux closures to improve future climate predictions and develop sustainable policies for Europe. Instrument platforms include ground-based, unmanned aerial vehicles (UAV), and satellite measurements of aerosols, clouds and meteorological variables. The ground-based and airborne measurements of aerosol size distributions and cloud condensation nuclei (CCN) concentration were used to initiate a 1D microphysical aerosol-cloud parcel model (ACPM). UAVs were equipped for a specific science mission, with an optical particle counter for aerosol distribution profiles, a cloud sensor to measure cloud extinction, or a 5-hole probe for 3D wind vectors. UAV cloud measurements are rare and have only become possible in recent years through the miniaturization of instrumentation. These are the first UAV measurements at Mace Head. ACPM simulations are compared to in-situ cloud extinction measurements from UAVs to quantify closure in terms of cloud radiative flux. Two out of seven cases exhibit sub-adiabatic vertical temperature profiles within the cloud, which suggests that entrainment processes affect cloud microphysical properties and lead to an overestimate of simulated cloud radiative flux. Including an entrainment parameterization and explicitly calculating the entrainment fraction in the ACPM simulations both improved cloud-top radiative closure. Entrainment reduced the difference between simulated and observation-derived cloud-top radiative flux (δRF) by between 30 W m−2 and 40 W m−2. After accounting for entrainment, satellite-derived cloud droplet number concentrations (CDNC) were within 30 % of simulated CDNC. In cases with a well-mixed boundary layer, δRF is less than 25 W m−2 after accounting for cloud-top entrainment, compared to less than 50 W m−2 when entrainment is not taken into account. In cases with a decoupled boundary layer, cloud microphysical properties are inconsistent with ground-based aerosol measurements, as expected, and δRF is as high as 88 W m−2, even after accounting for cloud-top entrainment. This work demonstrates the need to take in-situ measurements of aerosol properties for cases where the boundary layer is decoupled as well as consider cloud-top entrainment to accurately model stratocumulus cloud radiative flux.
The Variability of Relationship between Black Carbon and Carbon
Monoxide over the Eastern Coast of China: BC Aging during
Transport
Authors: Guo Qingfeng , Hu Min , Guo Song , Wu Zhijun , Peng Jianfei , Wu Yusheng
Published: March 2017

Abstract. East Asia is a densely populated region with a myriad of primary emissions of pollutants such as black carbon (BC) and carbon monoxide (CO). To characterize primary emissions over the eastern coast of China, a cascade of field campaign was conducted in 2011, including the measurement of ship cruise, island, and coastal receptor sites. The relationship between BC and CO is presented here for the first ship cruise (C1), the second ship cruise (C2), an island site (Changdao Island, CD), and a coastal site (Wenling, WL). The average BC mass concentrations are 2.43, 2.73, 1.09, 0.94, and 0.77 µg·m−3 for CD, WL, C1-YS (Yellow Sea), C1-ES (East China Sea), and C2-ES, respectively. For those locations, the average CO mixing ratios are 0.55, 0.48, 0.31, 0.36, and 0.27 ppm. The high loadings of both BC and CO imply the severe anthropogenic pollution over the eastern coast of China. Additionally, the linear correlation between BC and CO is regressed for each location. The slopes, i.e. ∆BC/∆CO ratios derived from their relationships are correlated well with the ratios of diesel consumption to gasoline consumption in each province/city, which reveals the vehicular emission as the common source for BC and CO and the distinct fuel structures between North and South China. The ∆BC/∆CO ratios at coastal sites (Changdao Island and Wenling) are much higher than those over Yellow Sea and East China Sea, and the correlation coefficients also show a decreasing trend from the coast to the sea. Therefore, the ∆BC/∆CO ratio and correlation coefficient are possible indicators for the aging and removal of BC.
Collection efficiency of α-pinene secondary organic aerosol particles explored via light-scattering single-particle aerosol mass spectrometry
Authors: Robinson Ellis Shipley , Onasch Timothy B. , Worsnop Douglas , Donahue Neil M.
Published: March 2017

Abstract. We investigated the collection efficiency and effective ionization efficiency for secondary organic aerosol (SOA) particles made from α-pinene + O3 using the single-particle capabilities of the aerosol mass spectrometer (AMS). The mean count-based collection efficiency (CEp) for SOA across these experiments is 0.30 (±0.04 SD), ranging from 0.25 to 0.40. The mean mass-based collection efficiency (CEm) is 0.49 (±0.07 SD). This sub-unit collection efficiency and delayed vaporization is attributable to particle bounce in the vaporization region. Using the coupled optical and chemical detection of the light-scattering single-particle (LSSP) module of the AMS, we provide clear evidence that delayed vaporization is somewhat of a misnomer for these particles: SOA particles measured as a part of the AMS mass distribution do not vaporize at a slow rate; rather, they flash-vaporize, albeit often not on the initial impact with the vaporizer but instead upon a subsequent impact with a hot surface in the vaporization region. We also find that the effective ionization efficiency (defined as ions per particle, IPP) decreases with delayed arrival time. CEp is not a function of particle size (for the mobility diameter range investigated, 170–460 nm), but we did see a decrease in CEp with thermodenuder temperature, implying that oxidation state and/or volatility can affect CEp for SOA. By measuring the mean ions per particle produced for monodisperse particles as a function of signal delay time, we can separately determine CEp and CEm and thus more accurately measure the relative ionization efficiency (compared to ammonium nitrate) of different particle types.
Pyranometer offsets triggered by ambient meteorology: insights from laboratory and field experiments
Authors: Oswald Sandro M. , Pietsch Helga , Baumgartner Dietmar J. , Weihs Philipp , Rieder Harald E.
Published: March 2017

Abstract. This study investigates the effects of ambient meteorology on the accuracy of radiation (R) measurements performed with pyranometers contained in various heating and ventilation systems (HV-systems). It focuses particularly on instrument offsets observed following precipitation events. To quantify pyranometer responses to precipitation, a series of controlled laboratory experiments as well as two targeted field campaigns were performed in 2016. The results indicate that precipitation (as simulated by spray tests or observed under ambient conditions) significantly affects the thermal environment of the instruments and thus their stability. Statistical analyses of laboratory experiments showed that precipitation triggers zero offsets of −4 W m−2 or more, independent of the HV-system. Similar offsets were observed in field experiments under ambient environmental conditions, indicating a clear exceedance of BSRN (Baseline Surface Radiation Network) targets following precipitation events. All pyranometers required substantial time to return to their initial signal states after the simulated precipitation events. Therefore, for BSRN-class measurements, the recommendation would be to flag the radiation measurements during a natural precipitation event and 90 min after it in nighttime conditions. Further daytime experiments show pyranometer offsets of 50 W m−2 or more in comparison to the reference system. As they show a substantially faster recovery, the recommendation would be to flag the radiation measurements within a natural precipitation event and 10 min after it in daytime conditions.
Diurnal variations in integrated water vapor derived from a GPS ground network in the Volga–Ural region of Russia
Authors: Kalinnikov Vladislav V. , Khutorova Olga G.
Published: March 2017

Abstract. In this article, we present estimates of diurnal and semidiurnal harmonics of variations in integrated water vapor content (IWV) according to data from 16 GPS stations in the Volga–Ural region of Russia during 2013–2015. Amplitudes of diurnal harmonics are maximal in summer and reach values from 0.37 to 1.01 mm. Time at the maximum of diurnal harmonic is typically in the period from 14:00 to 17:00. Semidiurnal harmonics have the largest amplitudes in spring and autumn, but they do not exceed 0.19 mm. A comparison of the diurnal cycle from GPS data and ERA-Interim reanalysis has revealed significant differences in the phase. It is established that, as a result of evaporation from the underlying surface and convective lifting of moist air, the summer diurnal variations in IWV and surface density of water vapor are in antiphase. The diurnal cycle of IWV is determined by surface air temperature to be 88 % in summer and less than at 35 % in other seasons. It is noted that maximal amplitudes of diurnal harmonic of IWV are observed at stations located on the windward side of mountains.
Observing and modelling phytoplankton community structure in the North Sea
Authors: Ford David A. , van der Molen Johan , Hyder Kieran , Bacon John , Barciela Rosa , Creach Veronique , McEwan Robert , Ruardij Piet , Forster Rodney
Published: March 2017

Abstract. Phytoplankton form the base of the marine food chain, and knowledge of phytoplankton community structure is fundamental when assessing marine biodiversity. Policy makers and other users require information on marine biodiversity and other aspects of the marine environment for the North Sea, a highly productive European shelf sea. This information must come from a combination of observations and models, but currently the coastal ocean is greatly under-sampled for phytoplankton data, and outputs of phytoplankton community structure from models are therefore not yet frequently validated. This study presents a novel set of in situ observations of phytoplankton community structure for the North Sea using accessory pigment analysis. The observations allow a good understanding of the patterns of surface phytoplankton biomass and community structure in the North Sea for the observed months of August 2010 and 2011. Two physical–biogeochemical ocean models, the biogeochemical components of which are different variants of the widely used European Regional Seas Ecosystem Model (ERSEM), were then validated against these and other observations. Both models were a good match for sea surface temperature observations, and a reasonable match for remotely sensed ocean colour observations. However, the two models displayed very different phytoplankton community structures, with one better matching the in situ observations than the other. Nonetheless, both models shared some similarities with the observations in terms of spatial features and inter-annual variability. An initial comparison of the formulations and parameterizations of the two models suggests that diversity between the parameter settings of model phytoplankton functional types, along with formulations which promote a greater sensitivity to changes in light and nutrients, is key to capturing the observed phytoplankton community structure. These findings will help inform future model development, which should be coupled with detailed validation studies, in order to help facilitate the wider application of marine biogeochemical modelling to user and policy needs.
Viable cold-tolerant iron-reducing microorganisms in geographically diverse subglacial environments
Authors: Nixon Sophie L. , Telling Jon P. , Wadham Jemma L. , Cockell Charles S.
Published: March 2017

Abstract. Subglacial environments are known to harbour metabolically diverse microbial communities. These microbial communities drive chemical weathering of underlying bedrock and influence the geochemistry of glacial meltwater. Despite its importance in weathering reactions, the microbial cycling of iron in subglacial environments, in particular the role of microbial iron reduction, is poorly understood. In this study we address the prevalence of viable iron-reducing microorganisms in subglacial sediments from five geographically isolated glaciers. Iron-reducing enrichment cultures were established with sediment from beneath Engabreen (Norway), Finsterwalderbreen (Svalbard), Leverett and Russell glaciers (Greenland), and Lower Wright Glacier (Antarctica). Rates of iron reduction were higher at 4 °C compared with 15 °C in all but one duplicated second-generation enrichment culture, indicative of cold-tolerant and perhaps cold-adapted iron reducers. Analysis of bacterial 16S rRNA genes indicates Desulfosporosinus were the dominant iron-reducing microorganisms in low-temperature Engabreen, Finsterwalderbreen and Lower Wright Glacier enrichments, and Geobacter dominated in Russell and Leverett enrichments. Results from this study suggest microbial iron reduction is widespread in subglacial environments and may have important implications for global biogeochemical iron cycling and export to marine ecosystems.
Can land degradation drive differences in the C exchange of two
similar semiarid ecosystems?
Authors: López-Ballesteros Ana , Oyonarte Cecilio , Kowalski Andrew S. , Serrano-Ortiz Penélope , Sánchez-Cañete Enrique P. , Moya M. Rosario , Domingo Francisco
Published: March 2017

Abstract. The concept of land degradation stems from the loss of an ecosystem's biological productivity, which in turn relies on several degradation processes, such as long-term loss of natural vegetation, depletion of soil nutrients, soil compaction or water and wind erosion, to which drylands are especially vulnerable. Currently, drylands occupy more than one third of the global terrestrial surface and will probably expand under future climate change scenarios. Drylands' key role in the global C balance has been recently demonstrated, but the effects of land degradation on C sequestration by these ecosystems needs further research. In the present study, we compare net carbon exchange, together with satellite data and meteorological, ambient and vadose zone (CO2, water content and temperature) variables, between two nearby (~23 km) experimental sites representing natural (i.e. site of reference) and degraded grazed semiarid grasslands located in SE Spain, via eddy covariance measurements over 6 years, with highly variable precipitation magnitude and distribution. Results show a striking difference in the annual C balances with an average release of 196 ± 40 and −23 ± 20 g C m−2 yr−1 for the degraded and natural sites, respectively. At the seasonal scale, differing patterns in net CO2 fluxes were detected over both growing and dry seasons. As expected, during the growing seasons, greater net C uptake over longer periods was observed in the natural site, however, much greater net C release was measured in the degraded site during drought periods. We tested differences in all monitored meteorological and soil variables and found it most relevant that CO2 at 1.50 m belowground was around 1000 ppm higher in the degraded site. Thus, we believe that subterranean ventilation of this vadose zone CO2, previously observed at both sites, largely drives the differences in C dynamics between them, especially during the dry season maybe due to enhanced subsoil-atmosphere interconnectivity in the degraded site. Overall, the 12 site-years of data allow direct exploration of the roles of climate and land degradation in the biological and non-biological processes that ultimately control the C sequestration capacity of semiarid ecosystems.
The Fate of a Southwest Pacific Bloom: Gauging the impact of submesoscale vs. mesoscale circulation on biological gradients in the subtropics
Authors: de Verneil Alain , Rousselet Louise , Doglioli Andrea M. , Petrenko Anne A. , Moutin Thierry
Published: March 2017

Abstract. The temporal evolution of a surface chlorophyll-a bloom sampled in the Western Tropical South Pacific during the 2015 Oligotrophy to UlTra-oligotrophy PACific Experiment cruise is examined. This region is usually characterized by largely oligotrophic conditions, ie low concentrations of inorganic nutrients at the surface and deep chlorophyll-a maxima. Therefore, the presence of a surface bloom represents a significant perturbation from the mean ecological state. Combining in situ and remote sensing datasets, we characterize both the bloom's biogeochemical properties as well as the physical circulation responsible for structuring it. Biogeochemical observations of the bloom document the bloom itself, a subsequent decrease of surface chlorophyll-a, significantly reduced surface phosphate concentrations relative to subtropical gyre water farther east, and a physical decoupling of chlorophyll-a from a deep nitracline. All these characteristics are consistent with nitrogen fixation occurring within the bloom. The physical data suggest surface mesoscale circulation is the primary mechanism driving the bloom’s advection, whereas balanced motions expected at submesoscales provide little contribution to observed flow. Together, the data provide a narrative where subtropical gyre water can produce significant chlorophyll-a concentrations at the surface that is stirred, deformed, and transported great distances by the mesoscale circulation. In this case, for the time period considered the transport is in an easterly direction, contrary to both the large-scale and mean mesoscale flow. As a result, future studies concerning surface production in the region need to take into account the role complex mesoscale structures play in redistributing subtropical gyre water.
Southern hemisphere bog persists as a strong carbon sink during droughts
Authors: Goodrich Jordan P. , Campbell Dave I. , Schipper Louis A.
Published: March 2017

Abstract. Peatland ecosystems have been important global carbon sinks throughout the Holocene. Most of the research on peatland carbon budgets and effects of variable weather conditions has been done in Northern Hemisphere Sphagnum-dominated systems. Given their importance in other geographic and climatic regions, a better understanding of peatland carbon dynamics is needed across the spectrum of global peatland types. In New Zealand, much of the historic peatland area has been drained for agriculture but little is known about rates of carbon exchange and storage in unaltered peatland remnants that are dominated by the jointed wire-rush, Empodisma robustum. We used eddy covariance to measure ecosystem-scale CO2 and CH4 fluxes and a water balance approach to estimate the sub-surface flux of dissolved organic carbon from the largest remaining raised peat bog in New Zealand, Kopuatai bog. The net ecosystem carbon balance (NECB) was estimated over four years, which included two drought summers, a relatively wet summer, and a meteorologically average summer. In all measurement years, the bog was a substantial sink for carbon, ranging from 134.7 gC m−2 yr−1 to 216.9 gC m−2 yr−1, owing to the large annual net ecosystem production (−161.8 to −244.9 gCO2-C m−2 yr−1). Annual methane fluxes were large relative to most Northern Hemisphere peatlands (14.2 to 21.9 gCH4-C m−2 yr−1), although summer and autumn emissions were highly sensitive to dry conditions leading to very predictable seasonality according to water table position. The annual flux of dissolved organic carbon was similar in magnitude to methane emissions but less variable, ranging from 11.7 to 12.8 gC m−2 yr−1. Dry conditions experienced during late summer droughts led to significant reductions in annual carbon storage, which resulted nearly equally from enhanced ecosystem respiration due to lowered water tables and increased temperatures, and from reduced gross primary production due to vapor pressure deficit-related stresses to the vegetation. However, the net C uptake of Kopuatai bog during drought years was large relative to even the maximum reported NECB from Northern Hemisphere bogs. Furthermore, GWP fluxes indicated the bog was a strong sink for greenhouse gases in all years despite the relatively large annual methane emissions. Our results suggest that adaptations of E. robustum to dry conditions lead to a resilient peatland drought response of the NECB.
MicroHH 1.0: a computational fluid dynamics code for direct numerical simulation and large-eddy simulation of atmospheric boundary layer flows
Authors: van Heerwaarden Chiel C. , van Stratum Bart J. H. , Heus Thijs , Gibbs Jeremy A. , Fedorovich Evgeni , Mellado Juan-Pedro
Published: March 2017

Abstract. This paper describes MicroHH 1.0, a new and open source (www.microhh.org) computational fluid dynamics code for the simulation of turbulent flows in the atmosphere. It is primarily made for direct numerical simulation, but also supports large-eddy simulation (LES). The paper covers the description of the governing equations, their numerical implementation, and the parametrizations included in the code. Furthermore, the paper presents the validation of the dynamical core in the form of convergence and conservation tests, and comparison of simulations of channel flows and slope flows against well-established test cases. The full numerical model, including the associated parametrizations for LES, has been tested for a set of cases under stable and unstable conditions, under the Boussinesq and anelastic approximation, and with dry and moist convection under stationary and time-varying boundary conditions. The paper presents performance tests showing good scaling from 256 to 32,768 processes. The Graphical Processing Unit-enabled version of the code reaches speedups of more than an order of magnitude with respect to the conventional code for a variety of cases.