bluuebunny/crossref_metadata_2025 huggingface dataset:
Mobile Devices and Apps, Characteristics and Current Potential on Learning
Authors: Briz-Ponce Laura , Juanes-Méndez Juan Antonio
Published: February 2016

Mobile devices and apps are placed in a prominent position in the daily routine of all people. The ubiquity and mobility are their main advantages. They are really becoming tools available for students and professionals in order to be totally connected anywhere and for consulting and accessing information of any field. In fact, the use of these devices has sparked a positive impact on medical sector as they allow implementing and including new technologies to make students more prepared for their future work. The goal of this paper is to describe the main characteristics and the use of mobile technologies in this field. The mobile technology's scope covers tablets and Smartphones. To achieve this goal, a survey was conducted in the University of Salamanca and the participants were undergraduate students of Medical Schools and medical professionals. Results reveal that the usage of mobile devices and apps are spread out among them. However, it is still necessary an in-depth analysis of the potential and the use of specialized apps for medical education.
Key Technologies of Diamond Tool Cutting of Ferrous Metals with Ultrasonic Vibration
Authors: Wang Hai Long , Du Xue , Wang Su Juan
Published: February 2016

The paper presents a review on the current situation of diamond tool ultrasonic vibration cutting ferrous metal. The key technology of diamond tool ultrasonic vibration cutting ferrous metals is presented in this paper and the influence of the processing environment of the presence of carbon atoms protective gas, the presence of carbon particles coolant of temperature control technology, ultrasonic vibration, workpiece material surface pretreatment or without on diamond tool wear rate and workpiece surface quality, the relationship between diamond tool wear rate, the workpiece surface quality and the ultrasonic vibration technology, processing environment, workpiece material surface pretreatment technology factors is given. Propose research direction and research emphasis on reducing diamond tool wear rate and improve workpiece surface quality.
A Novel Tool Wear Measurement Method in Ultra-Precision Raster Milling
Authors: Zhang Guo Qing , To Suet
Published: February 2016

Tool wear measurement has drawn a significant of attention in the past decades. However, no research has been found on the investigation of tool wear measurement in ultra-precision raster milling (UPRM) process since it is a relative complex cutting process. In the present study, tool wear characteristics were identified by using cutting chip morphologies and a groove cutting. Tool wear investigation using cutting chips is effective because diamond tool wear characteristics can be directly imprinted on the cutting chip surface. Through the inspection of chip surfaces, the profile and location of the tool fracture can be identified. Also, through the groove cutting, the cutting edge retreat due to the tool flank wear can be identified. In this research, a mathematical model was established to calculate the tool retreat. The experimental result shows that the proposed tool wear investigation method is an effective method.
Design and Analysis of a Planar Piezo-Actuated Nanopositioner with Millimeter Scale Stroke
Authors: Tang Hui , Gao Jian , Chen Xin , Zhang Lan Yu , Zeng Zhao He
Published: February 2016

In recent years, Fast Tool Servo (FTS) mechanism in precision manufacturing equipment emerges as a promising application for the piezo-actuated flexible nanopositioner. A flexible nanopositioner with large stroke, high bandwidth, high precision and multi-Degrees-of-Freedom (multi-DOFs) is really desired for this application. In order to meet this requirement, a novel 2-DOF flexible nanopositioner consists of two pairs of differential lever displacement amplifiers (DLDA) is proposed in this paper first, also, kinetostatics modeling is conducted by using the Pseudo-Rigid Body (PRB) method. After a series of mechanism optimal designs, the performance of the designed nanopositioner is verified by using the Finite Element Analysis (FEA) method. A piezoelectric (PZT) actuator with 90 µm is selected in this simulation, the experimental results indicate that the mechanism workspace can achieve around 2.1×2.1 mm2, the bandwidth can reach up to around 136 Hz, while the cross-coupling is also kept with 1%. All the results consistently prove the proposed device possesses satisfactory performance for fulfilling the practical precision manufacturing tasks.
A Framework of Data Fusion Algorithm for Precision Measurement of Multiscale Surfaces
Authors: Liu Ming Yu , Cheung Chi Fai , Ren Ming Jun , Cheng Ching Hsiang , Kong Ling Bao , Lee Wing Bun
Published: February 2016

Multiscale surfaces enriched with different scales of features are becoming widely used in many fields such as MEMS and optics industries. Due to the complexity of the multiple scale geometries, a single sensor or a single measurement can hardly obtain the holistic information of these surfaces. Multiple measurement method can solve this problem while it will introduce a lot of challenges for multiscale data fusion for the measurement results. This paper presents a framework of a data fusion algorithm for precision measurement of multiscale surfaces. The method makes use of iterative closest point based method to precisely register the datasets obtained in multiple measurements, and a Gaussian zero-order regression filter is used to separate the geometric features in different scales. Hence, the datasets are fused based on an edge intensity data fusion algorithm within the same wavelength. Finally, the fused datasets of different wavelengths were merged and replaced to the corresponding area in the large scale measurement to form a new surface with holistic multiscale information. The effectiveness of the proposed method has been verified on a v-grooved surface through a series of simulation experiments
Modeling and Adaptive Control Based on Actor-Critic Algorithm for a Piezo-Positioning System
Authors: Chen Xue Song , Chen Xin , Wang Han
Published: February 2016

In this paper, we present a new approach for modeling the hysteresis nonlinearity of a piezo-positioning systems. Because of its nonlinear hysteresis effect, the tracking control accuracy of the precision positioning system is difficulty achieved. Hence it is desirable to take hysteresis effect into consideration for improving the trajectory performance. A model reference adaptive optimal control scheme based on online actor-critic algorithm is developed. The proposed controller can be constructed without a nonlinear hysteresis dynamic equation to compensate the hysteresis effect. Simulation results show the effectiveness of the new approach.
Optimal Structural Design of Micro-Motion Stage with Stiffness Constraints Using Topology and Sizing Optimization Method
Authors: Bai You Dun , Yang Zhi Jun , Chen Xin , Wang Meng
Published: February 2016

Flexure hinge is widely used in the compliant mechanisms for precision engineering. Generally, compliant mechanisms with flexure hinges are designed using the analytical stiffness formulas, which increases the design complexity. As the development of finite element analysis (FEA) and optimization methods, it is likely to design the flexure hinges directly using the FEA based numerical optimization methods. This paper developed a leaf spring type flexure hinge based micro-motion stage with specific stiffness constraints. Both topology and sizing optimization methods are used in the design of motion stage. The proposed methods is apply to optimal design formed the leaf spring type flexure hinge for a micro motion stage which serves as a guidance mechanism. Further numerical result shows the good stiffness stability of the refined stage.
A Bedside Decision Tree for Use of Saline With Endotracheal Tube Suctioning in Children
Authors: Owen Erin B. , Woods Charles R. , O’Flynn Justine A. , Boone Megan C. , Calhoun Aaron W. , Montgomery Vicki L.
Published: February 2016

BACKGROUND

Endotracheal tube suctioning is necessary for patients receiving mechanical ventilation. Studies examining saline instillation before suctioning have demonstrated mixed results.

METHODS

A prospective study to evaluate whether saline instillation is associated with an increased risk of suctioning-related adverse events in patients 18 years old or younger requiring mechanical ventilation through an endotracheal tube for at least 48 hours when suctioned per protocol using a bedside decision tree.

RESULTS

A total of 1986 suctioning episodes (1003 with saline) were recorded in 69 patients. The most common indication for use of saline was thick secretions (87% of episodes). In 586 suctioning episodes, at least 1 adverse event occurred with increased frequency in the saline group (P < .001). Normal saline was more likely to be associated with hemodynamic instability (P = .04), bronchospasm (P < .001), and oxygen desaturation (P < .001). Patient factors associated with adverse events include younger age (P < .001), a cuffed endotracheal tube (P = .001), endotracheal tube diameter of 4.0 mm or less (P < .001), respiratory or hemodynamic indication for intubation (P < .001), underlying respiratory disease (P < .001), and longer duration of mechanical ventilation (P < .001). Saline instillation (P < .001), endotracheal tube size of 4.0 mm or less (P = .03), and comorbid respiratory diseases (P = .03) were associated with an increased risk of adverse events.

CONCLUSIONS

Saline instillation before endotracheal tube suctioning is associated with hemodynamic instability, bronchospasm, and transient hypoxemia. Saline should be used cautiously, especially in children with a small endotracheal tube and comorbid respiratory disease.
Alcohol Withdrawal Syndrome in Critically Ill Patients: Identification, Assessment, and Management
Authors: Sutton Lynsey J. , Jutel Annemarie
Published: February 2016

Management of alcohol withdrawal in critically ill patients is a challenge. The alcohol consumption histories of intensive care patients are often incomplete, limiting identification of patients with alcohol use disorders. Abrupt cessation of alcohol places these patients at risk for alcohol withdrawal syndrome. Typically benzodiazepines are used as first-line therapy to manage alcohol withdrawal. However, if patients progress to more severe withdrawal or delirium tremens, extra adjunctive medications in addition to benzodiazepines may be required. Sedation and mechanical ventilation may also be necessary. Withdrawal assessment scales such as the Clinical Institute of Withdrawal Assessment are of limited use in these patients. Instead, general sedation-agitation scales and delirium detection tools have been used. The important facets of care are the rapid identification of at-risk patients through histories of alcohol consumption, management with combination therapies, and ongoing diligent assessment and evaluation. (Critical Care Nurse. 2016;36[1]:28–39)
Acute Coronary Syndrome: Focus on Antiplatelet Therapy
Authors: Bobadilla Rodel V.
Published: February 2016

The American Heart Association/American College of Cardiology in 2014 published a focused update of the 2007 and 2012 guidelines for non–ST-segment elevation acute coronary syndrome (NSTE-ACS). The management of ST-segment elevation myocardial infarction (STEMI) is described in a separate guideline published in 2013. The focused updates to the guidelines contain updated recommendations for dual antiplatelet therapy, including use of the P2Y12 inhibitor ticagrelor, which was recently approved by the Food and Drug Administration. Nurses caring for patients with acute coronary syndrome must have a good understanding of the current treatment guidelines for such patients, to help ensure delivery of evidence-based care. This review article uses a case study–based approach to describe how the new guidelines affect clinical decision making when choosing appropriate antiplatelet therapy for patients with NSTE-ACS or STEMI, depending on the patient’s clinical history and presenting characteristics.
Vincenzo Rulli
Authors: Scardi Sabino
Published: February 2016

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Type A Acute Aortic Dissection in Nonagenarian: Rare but Possible
Authors: Citro Rodolfo , Patella Marco Mariano , Provenza Gennaro , Gregorio Giovanni , Bossone Eduardo
Published: February 2016

Acute type A aortic dissection (TA-AAD) is a highly lethal clinical entity that can occur within a wide age range, associated with multiple aetiologies and various clinical presentations. In the very elderly type A aortic dissection frequently presents with non-specific symptoms and signs and is associated with high mortality and morbidity. Thus the clinician must have a high index of clinical suspicion in order to prompt the most appropriate diagnostic-therapeutic strategy.We report a nonagenarian women with TA-AAD, treated successfully with medical therapy.
Consensus Statement of Multisocietary Task Force Prescription of physical exercise in the cardiological environment
Authors: Giada Franco , Carlon Roberto
Published: February 2016

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Psychosocial risk factors in cardiac practice
Authors: Giallauria Francesco , Battimiello Valentina , Veneziano Mariagrazia , De Luca Paolofabrizio , Cipollaro Ilenia , Buonincontro Maria , Vigorito Carlo , Del Forno Domenico
Published: February 2016

A large number of studies investigated the link between psychosocial risk factors and atherosclerosis or cardiac events. They found that emotional factors and chronic stressors strongly influence the course of coronary artery disease, by promoting the same pathophysiological mechanisms responsible for atherosclerosis. Thus, cardiologists often find in cardiac practice patients that presents psychosocial risk factors, needing the development of interventions aimed to management of these factors. Some of these interventions are the same that are traditionally used in clinical practice, such as exercise training and nutritional counselling, while others are more specific, and require the presence of psychologists (behavioral strategies, relaxation training, social support, etc.). Behavioral cardiology is an emerging field of clinical practice based on the recognition that psychosocial risk factors can promote atherosclerosis and adverse cardiac events. It requires the development of practical solutions aimed at the management of adverse lifestyle behaviours, emotional factors, and chronic stress.
Physical exercise and Sport activities in patients with and without coronary heart disease
Authors: Francavilla Giuseppe , Abrignani Maurizio Giuseppe , Braschi Annabella , Sciacca Rosalba , Francavilla Vincenzo Christian , Malvezzi Caracciolo Marco , Renda Nicola , Riccio Carmine , Scaglione Anna , Braschi Giambattista
Published: February 2016

Background: The quantity and intensity of physical activity required for the primary prevention of coronary heart disease remain unclear. Therefore, we examined the association between physical activity and coronary risk. Methods: We studied 100 patients with chest pain, 78 men and 22 women, not older than 65 years, admitted to a coronary care unit. Patients were subdivided in 3 groups: the first group included patients with acute myocardial infarction, the second group included patients with chronic heart disease, the third included patients with non-ischemic chest-pain. A questionnaire on daily physical activity was filled by each patient. Results: A significantly higher percentage of patients with myocardial infarction and coronary heart disease had a sedentary life style compared to patients of the third group. Compared with subjects without heart disease, a significantly higher percentage of patients of the first and second group covered a daily average distance shorter than 500 meters, while a significantly inferior percentage covered a distance longer than 1 Km every day. A significantly lower percentage of patients with coronary heart disease practised sport compared with the third group. At the time of hospitalization a very small percentage of coronary heart disease patients still practised sport. Conclusions: The association between physical activity and reduced coronary risk is clear; in order to obtain benefits it is sufficient just walking every day. Regarding physical activity, continuity is important: patients, who practised sport only in juvenile age, breaking off when older, may lose the obtained advantages.
Raised homocystein plasma concentration in patients with Heart Failure: clinical significance
Authors: Vizzardi E. , Nodari S. , Fiorina C. , Metra M. , Dei Cas L.
Published: February 2016

Elevated plasma levels of homocysteine is associated with increased risk of thrombotic and atherosclerotic vascular disease. Several studies have demonstrated that hyperhomocysteinemia is an indipendent risk factor for vascular disease and is associated to heart failure. However there are no data regarding the association between homocysteine and various objective as well as subjective measures of heart failure. We hypothesized that plasma homocysteine is associated with clinical and echocardiographic signs of heart failure. On this ground we have analysed levels of homocysteine in patients with heart failure and possible correlation between these levels and clinical-functional pattern (NYHA class and ejection fraction). Methods: Plasma homocysteine levels were determined in 123 patients with dilated cardiomyopathy (59 males, 64 females, mean age 67±10 years, mean EF 31±11% and mean NYHA 2.4±0.9, 47 idiopatic and 76 postischemic cardiomyopathy) and 85 healthy control subjects (homogeneus group for sex and age). Patients with chronic renal failure, vitamin B12 and folate deficiency or factors affecting homocysteine plasma levels were escluded from this study. Homocysteine levels were determined in coded plasma samples by immunoenzimatic methods. Results: Patients with heart failure had a higher homocysteine level (mcg/L) than control subjects (21.72±10.28 vs 12.9±6.86, p<0,001) both postischemic (20.89±9.6 vs 12.9±6.86, p<0,001) and idiopatic cardiomiopathy (23.0±11.2 vs 12.9±6.86, p<0,001). A significant correlation was observed between homocysteine and NYHA functional class (p<0,001), age (p<0,001), creatinine (p<0,001), colesterol (p<0,05) while no correlations were observed with hemodynamic (HR, BP), functional (ejection fraction) and other metabolic parameters (triglycerides). Serum homocysteine was lowest in control and increased with increasing NYHA class. In idiopatic cardiomiopathy the correlation between homocysteine and NYHA functional class, creatinine (p<0,001), fibrinogen (p<0,05) was confirmed; in postischemic cardiomiopathy a significant correlation with creatinine and NYHA class (p<0,001) and with triglycerides (p<0,05) was also found. Conclusion: Plasma homocysteine was directly related to NYHA class. This observation may underline the strong relations of plasma homocysteine to congestive heart failure. Further research is indicated to evaluate a causal or noncausal mechanism for this association.
Cardiac Rehabilitation in the Health Plans of Campania
Authors: Scaglione Anna , Chieffo Carmine , Gregorio Giovanni , Riccio Carmine , Rosato Giuseppe , Scherillo Marino
Published: February 2016

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29th Congress of the Italian Society of Neonatology - Lombardy section | Bergamo, 29-30 January 2016
Authors: Musi Luciano , Frigiola Alessandro , Giovannini Marcello , Rosti Luca
Published: February 2016

This abstract book contains the abstracts presented at the 29th Congress of the Italian Society of Neonatology - Lombardy section | Bergamo, 29-30 January 2016.
NABIC: A New Access Portal to Search, Visualize, and Share Agricultural Genomics Data
Authors: Seol Young-Joo , Lee Tae-Ho , Park Dong-Suk , Kim Chang-Kug
Published: February 2016

The National Agricultural Biotechnology Information Center developed an access portal to search, visualize, and share agricultural genomics data with a focus on South Korean information and resources. The portal features an agricultural biotechnology database containing a wide range of omics data from public and proprietary sources. We collected 28.4 TB of data from 162 agricultural organisms, with 10 types of omics data comprising next-generation sequencing sequence read archive, genome, gene, nucleotide, DNA chip, expressed sequence tag, interactome, protein structure, molecular marker, and single-nucleotide polymorphism datasets. Our genomic resources contain information on five animals, seven plants, and one fungus, which is accessed through a genome browser. We also developed a data submission and analysis system as a web service, with easy-to-use functions and cutting-edge algorithms, including those for handling next-generation sequencing data.
Neuroprotective Effects against POCD by Photobiomodulation: Evidence from Assembly/Disassembly of the Cytoskeleton
Authors: Liebert Ann D. , Chow Roberta T. , Bicknell Brian T. , Varigos Euahna
Published: February 2016

Postoperative cognitive dysfunction (POCD) is a decline in memory following anaesthesia and surgery in elderly patients. While often reversible, it consumes medical resources, compromises patient well-being, and possibly accelerates progression into Alzheimer's disease. Anesthetics have been implicated in POCD, as has neuroinflammation, as indicated by cytokine inflammatory markers. Photobiomodulation (PBM) is an effective treatment for a number of conditions, including inflammation. PBM also has a direct effect on microtubule disassembly in neurons with the formation of small, reversible varicosities, which cause neural blockade and alleviation of pain symptoms. This mimics endogenously formed varicosities that are neuroprotective against damage, toxins, and the formation of larger, destructive varicosities and focal swellings. It is proposed that PBM may be effective as a preconditioning treatment against POCD; similar to the PBM treatment, protective and abscopal effects that have been demonstrated in experimental models of macular degeneration, neurological, and cardiac conditions.
Vitamin D and the Promotion of Long-Term Metabolic Health from a Programming Perspective
Authors: Palaniswamy Saranya , Williams Dylan , Järvelin Marjo-Riitta , Sebert Sylvain
Published: February 2016

Studies linking vitamin D and long-term metabolic health have generated much debate. Recommendations for the intake of vitamin D by the general public and by the health care professionals have been complicated by a number of inconsistencies in the literature. These caveats relate to the methodological approaches, differences in the populations (and the species) of study, and the definitions used for thresholds of vitamin D status. This review addresses current evidence available for assessing the potential programming of long-term metabolic health of offspring by maternal vitamin D status in pregnancy. It summarizes knowledge on the early origins of metabolic health and analyzes evidence for an association between the vitamin D status in pregnancy and maternal and fetal health status. In addition, we analyze the link between the regulation of inflammation and the vitamin D status in the general population to inform on the general mechanisms through which early vitamin D might affect the programming of long-term health. The evidence suggests an association between the vitamin D status in early life and the programming of long-term health. However, to the best of our knowledge, the current finding is insufficient to draw a final conclusion for evidence-based preventive actions. The data warrant replication in prospective studies and additional research substantiating the causal factors and pathways.
An Adaptive Perfectly Matched Layer Method for Multiple Cavity Scattering Problems
Authors: Wu Xinming , Zheng Weiying
Published: February 2016

A uniaxial perfectly matched layer (PML) method is proposed for solving the scattering problem with multiple cavities. By virtue of the integral representation of the scattering field, we decompose the problem into a system of single-cavity scattering problems which are coupled with Dirichlet-to-Neumann maps. A PML is introduced to truncate the exterior domain of each cavity such that the computational domain does not intersect those for other cavities. Based on the a posteriori error estimates, an adaptive finite element algorithm is proposed to solve the coupled system. The novelty of the proposed method is that its computational complexity is comparable to that for solving uncoupled single-cavity problems. Numerical experiments are presented to demonstrate the efficiency of the adaptive PML method.
Asymptotic-Preserving Scheme for the M1-Maxwell System in the Quasi-Neutral Regime
Authors: Guisset S. , Brull S. , Dubroca B. , d'Humières E. , Karpov S. , Potapenko I.
Published: February 2016

This work deals with the numerical resolution of the M1-Maxwell system in the quasi-neutral regime. In this regime the stiffness of the stability constraints of classical schemes causes huge calculation times. That is why we introduce a new stable numerical scheme consistent with the transitional and limit models. Such schemes are called Asymptotic-Preserving (AP) schemes in literature. This new scheme is able to handle the quasi-neutrality limit regime without any restrictions on time and space steps. This approach can be easily applied to angular moment models by using a moments extraction. Finally, two physically relevant numerical test cases are presented for the Asymptotic-Preserving scheme in different regimes. The first one corresponds to a regime where electromagnetic effects are predominant. The second one on the contrary shows the efficiency of the Asymptotic-Preserving scheme in the quasi-neutral regime. In the latter case the illustrative simulations are compared with kinetic and hydrodynamic numerical results.
Patch-Recovery Filters for Curvature in Discontinuous Galerkin-Based Level-Set Methods
Authors: Kummer Florian , Warburton Tim
Published: February 2016

In two-phase flow simulations, a difficult issue is usually the treatment of surface tension effects. These cause a pressure jump that is proportional to the curvature of the interface separating the two fluids. Since the evaluation of the curvature incorporates second derivatives, it is prone to numerical instabilities. Within this work, the interface is described by a level-set method based on a discontinuous Galerkin discretization. In order to stabilize the evaluation of the curvature, a patch-recovery operation is employed. There are numerous ways in which this filtering operation can be applied in the whole process of curvature computation. Therefore, an extensive numerical study is performed to identify optimal settings for the patch-recovery operations with respect to computational cost and accuracy.
On the Disclination Lines of Nematic Liquid Crystals
Authors: Hu Yucheng , Qu Yang , Zhang Pingwen
Published: February 2016

Defects in liquid crystals are of great practical importance and theoretical interest. Despite tremendous efforts, predicting the location and transition of defects under various topological constraint and external field remains to be a challenge. We investigate defect patterns of nematic liquid crystals confined in three-dimensional spherical droplet and two-dimensional disk under different boundary conditions, within the Landau-de Gennes model. We implement a spectral method that numerically solves the Landau-de Gennes model with high accuracy, which allows us to study the detailed static structure of defects. We observe five types of defect structures. Among them the 1/2-disclination lines are the most stable structure at low temperature. Inspired by numerical results, we obtain the profile of disclination lines analytically. Moreover, the connection and difference between defect patterns under the Landau-de Gennes model and the Oseen-Frank model are discussed. Finally, three conjectures are made to summarize some important characteristics of defects in the Landau-de Gennes theory. This work is a continuing effort to deepen our understanding on defect patterns in nematic liquid crystals.
Estabilidad de personas en flujos de agua
Authors: Martínez-Gomariz E. , Gómez M. , Russo B.
Published: February 2016

Nuestras ciudades están formadas por diversos elementos que están expuestos a inundaciones de magnitudes acordes al evento de lluvia que se produzca y según el diseño del sistema de drenaje urbano. Los elementos más importantes en las ciudades son los peatones, los cuales desarrollan en éstas actividades diversas. Centrando la atención en éstos, la investigación relacionada con su estabilidad cuando se ven sometidos al flujo del agua en la calle proporciona un conocimiento que permite entender y gestionar la peligrosidad asociada a tales situaciones. En el presente estudio se han llevado a cabo experimentos con personas para determinar sus límites de estabilidad, cruzando a través de un flujo de agua en una plataforma de ensayos a escala real. Los resultados obtenidos hasta el momento proporcionan un criterio de peligrosidad mucho más restrictivo que aquellos proporcionados por otros autores o directrices utilizadas en la actualidad.
Do Transfer Costs Matter for Foreign Remittances? A Gravity Model Approach
Authors: Ahmed Junaid , Martínez-Zarzoso Inmaculada
Published: February 2016

Using bilateral data on remittance flows to Pakistan for 23 major host countries, this is the first study that examines the effect of transaction costs on foreign remittances. The authors find that the effect of transaction costs on remittance flows is negative and significant; suggesting that a high cost will either refrain migrants from sending money back home or make them remit through informal channels. They also find that remittances are facilitated by the existence of migrant networks and improvements in home and host country financial services. Distance, which has been used in previous studies as an indicator of the cost of remitting, is found to be a poor proxy.
Urban increments of gaseous and aerosol pollutants and their sources using mobile aerosol mass spectrometry measurements
Authors: Elser M. , Bozzetti C. , El-Haddad I. , Maasikmets M. , Teinemaa E. , Richter R. , Wolf R. , Slowik J. G. , Baltensperger U. , Prévôt A. S. H.
Published: February 2016

Abstract. Air pollution is one of the main environmental concerns in urban areas, where anthropogenic emissions strongly affect air quality. This work presents the first spatially-resolved detailed characterization of the PM2.5 in two major Estonian cities (Tallinn and Tartu), using mobile measurements. In both cities, the non-refractory (NR)-PM2.5 was characterized by a highresolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) using a recently developed lens which increases the transmission of super-micron particles. Equivalent black carbon (eBC) and several trace gases including carbon monoxide (CO), carbon dioxide (CO2) and methane (CH4) were also measured. The chemical composition of the PM2.5 was found to be very similar in the two cities. Organic aerosol (OA) constituted the largest fraction, explaining on average about 52 to 60 % of the PM2.5 mass. Four sources of OA were identified using positive matrix factorization (PMF): hydrocarbon-like OA (HOA, from traffic emissions), biomass burning OA (BBOA, from biomass combustion), residential influenced OA (RIOA, probably mostly from cooking processes with possible contributions from waste and coal burning) and oxygenated OA (OOA, related to secondary aerosol formation). OOA was the major OA source during night-time, explaining on average half of the OA mass, while during day-time mobile measurements the OA was affected by point sources and dominated by the primary fraction. A strong increase in the secondary organic and inorganic components was observed during periods with transport of air masses from polluted continental areas, while the primary local emissions accumulated during periods with temperature inversions. Mobile measurements offered the identification of different source regions within the urban areas and an accurate calculation of the urban increments. HOA, eBC, CO2 and CO showed stronger enhancements on busy roads during the morning and evening traffic rush hours; BBOA had its maximum enhancement in the residential areas during the evening hours and RIOA was enhanced in both the city center (emissions from restaurants) and in the residential areas (emissions from residential cooking). In contrast, secondary components (OOA, SO4, NO3, NH4, and Cl) had very homogeneous distributions in time and space. We were able to determine a total PM2.5 urban increment in Tartu of 6.0 μg m−3 over a regional background concentration of 4.0 μg m−3 (i.e., a factor of 2.5 increase). Traffic exhaust emissions were identified as the most important source of this increase, with eBC and HOA explaining on average 53.3 and 20.5 % of the total increment, respectively.
Aircraft observations of water-soluble dicarboxylic acids in the aerosols over China
Authors: Zhang Yan-Lin , Kawamura Kimitaka , Fu Ping Qing , Boreddy Suresh K. R. , Watanabe Tomomi , Hatakeyama Shiro , Takami Akinori , Wang Wei
Published: February 2016

Abstract. Vertical profiles of low molecular weight dicarboxylic acids, related organic compounds and SOA tracer compounds in particle phase have not yet been simultaneously explored in East Asia, although there is growing evidence that aqueous phase oxidation of volatile organic compounds may be responsible for the elevated organic aerosols (OA) in the free troposphere. Here, we found consistently good correlation of oxalic acid, the most abundant organics globally, with its precursors as well as biogenic-derived secondary OA (SOA) compounds in Chinese tropospheric aerosols by aircraft measurements. Anthropogenically derived dicarboxylic acids (i.e., C5 and C6 diacids) at high altitudes were 4–20 times higher than those from surface measurements and even occasionally dominant over oxalic acid at altitude higher than 2 km, which is in contrast to the predominance of oxalic acid previously reported globally including the tropospheric and surface aerosols. This indicates an enhancement of tropospheric SOA formation from anthropogenic precursors. Furthermore, oxalic acid-tosulfate ratio maximized at altitude of ~2 km, explaining aqueous-phase SOA production that was supported by good correlations with predicted liquid water content, organic carbon and biogenic SOA tracers. These results demonstrate that elevated oxalic acid and related SOA compounds from both the anthropogenic and biogenic sources may substantially contribute to tropospheric OA burden over polluted regions of China, implying aerosol-associated climate effects and intercontinental transport.
A new setup for simultaneous high precision measurements of CO2, δ13C-CO2 and δ18O-CO2 on small ice core samples
Authors: Jenk T. M. , Rubino M. , Etheridge D. , Ciobanu V. G. , Blunier T.
Published: February 2016

Abstract. Paleo–atmospheric records of carbon dioxide and its stable carbon isotope composition (δ13C) obtained from polar ice cores provide important constraints on the natural variability of the carbon cycle. However, the measurements are both analytically challenging and time-consuming thus data exist only from a limited number of sampling sites and time periods. Additional analytical resources with high analytical precision and throughput are thus desirable to extend and confirm the existing datasets. Also, consistent measurements derived by independent laboratories and a variety of analytical systems helps to further increase confidence in the global CO2 paleo reconstructions. Here, we describe our new setup for simultaneous measurements of atmospheric CO2 mixing ratios, atmospheric δ13C and δ18O-CO2 in air extracted from ice core samples. The core of the system is a newly designed Needle Cracker for the mechanical release of air entrapped in ice core samples of 8–13 g operated at −45 °C. The small sample size allows for high resolution and replicate sampling schemes. In our method, CO2 is cryogenically and chromatographically separated from the bulk air and the isotopic composition subsequently determined by continuous flow isotope ratio mass spectrometry (IRMS). In combination with thermal conductivity measurement of the bulk air, the CO2 mixing ratio is calculated. The analytical precision determined from standard air sample measurements over ice is ± 1.9 ppm for CO2 and ± 0.09 ‰ for δ13C. In a laboratory intercomparison study with CSIRO (Aspendale, Australia) good agreement between CO2 and δ13C results is found for Law Dome ice core samples. Replicate analysis of these samples resulted in a pooled standard deviation of 2.0 ppm for CO2 and 0.11 ‰ for δ13C. These numbers are good, although rather conservative estimates of the overall analytical uncertainty for a single measurement. Facilitated by the small sample requirement, replicate measurements are feasible and the achievable method precision accordingly higher. Further in this study, new analytical approaches are introduced for the accurate correction of the procedural blank and for the reliable and consistent detection of measurement outliers which is based on δ18O-CO2 and the exchange of oxygen between CO2 and H2O of surrounding ice.
Top-of-the-atmosphere shortwave flux estimation from UV satellite observations: An empirical approach using data from the A-train constellation
Authors: Gupta Pawan , Joiner Joanna , Vasilkov Alexander , Bhartia P. K.
Published: February 2016

Abstract. Estimates of top of the atmosphere (TOA) radiative flux are essential for the understanding of Earth’s energy budget and climate system. Clouds, aerosols, water vapor, and ozone (O3) are among the most important atmospheric agents impacting the Earth’s short-wave (SW) radiation budget. There are several sensors in orbit that provide independent information related to these parameters. Having coincident information from these sensors is important for understanding their potential contributions. The A-train constellation of satellites provides a unique opportunity to analyze near-simultaneous data from several of these sensors. In this paper, retrievals of cloud/aerosols parameters and total column ozone (TCO) from the Aura Ozone Monitoring Instrument (OMI) have been collocated with the Aqua Clouds and Earth's Radiant Energy System (CERES) estimates of TOA SW flux (SWF). We use these data to develop a variety of neural networks that estimate TOA SWF globally over ocean and land using only OMI data as inputs. OMI-estimated TOA SWF reproduces the independent CERES data with high fidelity. The global mean daily TOA SWF calculated from OMI is consistently within ±1% of CERES throughout the year 2007. Application of our neural network to other ultraviolet sensors, both past and future, may provide unique estimates of TOA SWF. For example, the well-calibrated Total Ozone Mapping Spectrometer (TOMS) series could provide estimates of TOA SWF dating back to late 1978.
Comparison of GPS tropospheric delays derived from two consecutive EPN reprocessing campaigns from the point of view of climate monitoring
Authors: Baldysz Zofia , Nykiel Grzegorz , Araszkiewicz Andrzej , Figurski Mariusz , Szafranek Karolina
Published: February 2016

Abstract. The main purpose of this research was to acquire information about consistency of the ZTD (Zenith Tropospheric Delay) linear trends and seasonal components between two consecutive GPS reprocessing campaigns. The analysis concerned two sets of the ZTD time series which were estimated during EPN (EUREF Permanent Network) reprocessing campaigns according to 2008 and 2015 MUT LAC (Military University of Technology Local Analysis Centre) scenarios. Firstly, LombScargle periodograms were generated for 57 EPN stations to obtain characters of oscillations occurring in the ZTD time series. Then, the values of seasonal components and linear trends were estimated using the LSE (Least Square Estimation) approach. The Mann-Kendall Trend Test was also carried out to verify the presence of linear long term ZTD changes. Finally, differences in seasonal signals and linear trends between these two data sets were investigated. In case of spectral analysis, amplitudes of the annual and semiannual periods were almost exactly the same for both reprocessing campaigns. Exceptions were found for only a few stations and they did not exceed 1 mm. The estimated trends were also similar. However, in case of reprocessing performed in 2008, the trends values were generally higher than the values from the other one. All these analyses were conducted for two lengths of the ZTD time series: a shortened 16-year series, and a full 18-year one. In general, shortening of the analysed period of time resulted in decrease of the linear trends values of about 0.7 mm/decade. This was conﬁrmed by analyses based on two data sets.
Runoff- and erosion-driven transport of cattle slurry: linking molecular tracers to hydrological processes
Authors: Lloyd C. E. M. , Michaelides K. , Chadwick D. R. , Dungait J. A. J. , Evershed R. P.
Published: February 2016

Abstract. The addition of cattle slurry to agricultural land is a widespread practise, but if not correctly managed it can pose a contamination risk to aquatic ecosystems. The transport of inorganic and organic components of cattle slurry to watercourses is a major concern, yet little is known about the physical transport mechanisms and associated fluxes and timings of contamination threats. Therefore, the aim of the study was to ascertain the importance of flow pathway partitioning in the transport (fluxes and timing) of dissolved and particulate slurry-derived compounds with implications for off-site contamination. A series of rainfall–runoff and erosion experiments were carried out using the TRACE (Test Rig for Advancing Connectivity Experiments) experimental hillslope facility. The experiments allowed the quantification of the impact of changing slope gradient and rainfall intensity on nutrient transport from cattle slurry applied to the hillslope, via surface, subsurface, and vertical percolated flow pathways, as well as particulate transport from erosion. The dissolved components were traced using a combination of ammonium (NH4+) and fluorescence analysis, while the particulate fraction was traced using organic biomarkers, 5β-stanols. Results showed that rainfall events which produced flashy hydrological responses, resulting in large quantities of surface runoff, were likely to move sediment and also flush dissolved components of slurry-derived material from the slope, increasing the contamination risk. Rainfall events which produced slower hydrological responses were dominated by vertical percolated flows removing less sediment-associated material, but produced leachate which could contaminate deeper soil layers, and potentially groundwater, over a more prolonged period. Overall, this research provides new insights into the partitioning of slurry-derived material when applied to an unvegetated slope and the transport mechanisms by which contamination risks are created.
A novel permanent gauge-cam station for surface flow observations on the Tiber river
Authors: Tauro Flavia , Petroselli Andrea , Porfiri Maurizio , Giandomenico Lorenzo , Bernardi Guido , Mele Francesco , Spina Domenico , Grimaldi Salvatore
Published: February 2016

Abstract. Flow monitoring of riverine environments is crucial for hydrology and hydraulic engineering practice. Besides few experimental implementations, flow gauging relies on local water level and surface flow velocity measurements through ultrasonic meters and radars. In this paper, we describe a novel permanent gauge-cam station for large scale and continuous observation of surface flows, based on remote acquisition and calibration of video data. Located on the Tiber river, in the center of Rome, Italy, the station captures one-minute videos every 10 min over an area oriented along the river cross-section of up to 20.6 × 15.5 m2. In a feasibility study, we demonstrate that accurate surface flow velocity estimations can be obtained by analyzing experimental images via particle tracking velocimetry (PTV). In medium illumination conditions (70–75 lux), PTV leads to velocity estimations in close agreement with radar records and is less affected by uneven lighting than large scale particle image velocimetry. Future efforts will be devoted to the development of a comprehensive testbed infrastructure for investigating the potential of multiple optics-based approaches for surface hydrology.
Mars MOURA magnetometer demonstration for high resolution mapping on terrestrial analogues
Authors: Diaz Michelena Marina , Kilian Rolf , Sanz Ruy , Rios Francisco , Baeza Oscar
Published: February 2016

Abstract. Satellite-based magnetic measurements of Mars indicate complex and very strong magnetic anomalies, which led to an intensive and long-lasting discussion about their possible origin. To investigate the origin of these anomalies MOURA vector magnetometer was developed for future on ground surveys on Mars and tested on various terrestrial analogues characterised by most distinct magnetic anomalies of their basement rocks: (1) A magnetite body of EL Laco (up to +110 000 nT) and its transition to surrounding andesites (< +2000 nT) in the Northern Andes of Chile showing the highest local magnetic anomalies. The magnetite-bearing ore body has highly variable local anomalies due to their complex formation history where a significant dispersion in paleo-orientations has been previously reported, while our vector data show relatively uniform and probably induced declinations. (2) A basaltic spatter cone of the Pali Aike volcanic field, in Southern Chile, was characterised by very strong magnetic anomalies along the crater rim (up to +12 000 nT), controlled by the amount of single domain magnetites in the ground mass of the basalts. Due to their strong remanent signature paleodeclinations of the lavas and reorientations of collapsed blocks could be constrained by the vector data. (3) The Monturaqui meteorite crater (350 m diameter), in Northern Chile, shows significant variations of its anomalies (from −2000 to > +6000 nT) in restricted areas of several square metres along its crater rim related to unexposed iron-bearing fragments of the impactor while its granitic and ignimbritic target rocks exhibit only very weak anomalies. (4) An area with several amphibolitic dykes which cross-cut a Cretaceous granitoid in the southernmost Andes, where a decimetre-scale mapping was performed. In this case, pyrr hotite is the only magnetic carrier. It was formed during hydrothermal processes within the dykes. Very low (+40 to +120 nT) positive magnetic anomalies clearly depict the amount of 1 to 4 vol. % pyrrhotite in these dykes, which is important as a mineralogical indicator as well as to detect associated gold and copper enrichment.