bluuebunny/crossref_metadata_2025 huggingface dataset:
THE EXTENDED HALO OF CENTAURUS A: UNCOVERING SATELLITES, STREAMS, AND SUBSTRUCTURES*
Authors: Crnojević D. , Sand D. J. , Spekkens K. , Caldwell N. , Guhathakurta P. , McLeod B. , Seth A. , Simon J. D. , Strader J. , Toloba E.
Published: May 2016

We present the widest-field resolved stellar map to date of the closest (

Mpc) massive elliptical galaxy NGC 5128 (Centaurus A; Cen A), extending out to a projected galactocentric radius of ∼150 kpc. The data set is part of our ongoing Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS) utilizing the Magellan/Megacam imager. We resolve a population of old red giant branch (RGB) stars down to ∼1.5 mag below the tip of the RGB, reaching surface brightness limits as low as

mag arcsec−2. The resulting spatial stellar density map highlights a plethora of previously unknown streams, shells, and satellites, including the first tidally disrupting dwarf around Cen A (CenA-MM-Dw3), which underline its active accretion history. We report 13 previously unknown dwarf satellite candidates, of which 9 are confirmed to be at the distance of Cen A (the remaining 4 are not resolved into stars), with magnitudes in the range

to −13.0, central surface brightness values of

mag arcsec−2, and half-light radii of

. These values are in line with Local Group dwarfs but also lie at the faint/diffuse end of their distribution; interestingly, CenA-MM-Dw3 has similar properties to the recently discovered ultradiffuse galaxies in Virgo and Coma. Most of the new dwarfs are fainter than the previously known Cen A satellites. The newly discovered dwarfs and halo substructures are discussed in light of their stellar populations, and they are compared to those discovered by the PAndAS survey of M31.
FORMATION AND PLASMA CIRCULATION OF SOLAR PROMINENCES
Authors: Xia C. , Keppens R.
Published: May 2016

Solar prominences are long-lived cool and dense plasma curtains in the hot and rarefied outer solar atmosphere or corona. The physical mechanism responsible for their formation and especially for their internal plasma circulation has been uncertain for decades. The observed ubiquitous downflows in quiescent prominences are difficult to interpret because plasma with high conductivity seems to move across horizontal magnetic field lines. Here we present three-dimensional numerical simulations of prominence formation and evolution in an elongated magnetic flux rope as a result of in situ plasma condensations fueled by continuous plasma evaporation from the solar chromosphere. The prominence is born and maintained in a fragmented, highly dynamic state with continuous reappearance of multiple blobs and thread structures that move mainly downward, dragging along mass-loaded field lines. The circulation of prominence plasma is characterized by the dynamic balance between the drainage of prominence plasma back to the chromosphere and the formation of prominence plasma via continuous condensation. Plasma evaporates from the chromosphere, condenses into the prominence in the corona, and drains back to the chromosphere, establishing a stable chromosphere–corona plasma cycle. Synthetic images of the modeled prominence with the Solar Dynamics Observatory Atmospheric Imaging Assembly closely resemble actual observations, with many dynamical threads underlying an elliptical coronal cavity.
MAGELLAN AO SYSTEM z′, YS, AND L′ OBSERVATIONS OF THE VERY WIDE 650 AU HD 106906 PLANETARY SYSTEM*
Authors: Wu Ya-Lin , Close Laird M. , Bailey Vanessa P. , Rodigas Timothy J. , Males Jared R. , Morzinski Katie M. , Follette Katherine B. , Hinz Philip M. , Puglisi Alfio , Briguglio Runa , Xompero Marco
Published: May 2016

We analyze archival data from Bailey and co-workers from the Magellan adaptive optics system and present the first 0.9 μm detection (z′ = 20.3 ± 0.4 mag; Δz′ = 13.0 ± 0.4 mag) of the 11 M
Jup circumbinary planet HD 106906AB b, as well as 1 and 3.8 μm detections of the debris disk around the binary. The disk has an east–west asymmetry in length and surface brightness, especially at 3.8 μm where the disk appears to be one-sided. The spectral energy distribution of b, when scaled to the K

S
-band photometry, is consistent with 1800 K atmospheric models without significant dust reddening, unlike some young, very red, low-mass companions such as CT Cha B and 1RXS 1609 B. Therefore, the suggested circumplanetary disk of Kalas and co-workers might not contain much material, or might be closer to face-on. Finally, we suggest that the widest (a ≳ 100 AU) low mass ratio (M
p/M
⋆ ≡ q ≲ 0.01) companions may have formed inside protoplanetary disks but were later scattered by binary/planet interactions. Such a scattering event may have occurred for HD 106906AB b with its central binary star, but definitive proof at this time is elusive.
Théorie de la dominance économique et flux intra- et inter-territoriaux de connaissances technologiques
Authors: Lebert Didier
Published: May 2016

Cet article a pour objectif d’appréhender les flux intra- et interterritoriaux de connaissances technologiques par le biais de la théorie de la dominance économique. Des indicateurs structuraux de dépendance, d’interdépendance et d’autarcie territoriale ainsi que de centralité de cohésion sont présentés et appliqués à la base de données de citations de brevets tenue à jour par le NBER pour le marché américain des technologies. L’approche duale est également envisagée : celle des relations structurales entre technologies, qui permet de localiser les sources de l’innovation technologique sur ce marché. Codes JEL : O32, R11
Les symbioses industrielles : un nouveau champ d’analyse pour l’économie industrielle
Authors: Diemer Arnaud
Published: May 2016

Si la symbiose industrielle peut se définir comme un engagement de firmes indépendantes dans une logique collective visant à tirer avantage des échanges de flux de matières et d’énergies, elle se présente également comme un nouveau champ d’analyse pour l’économie industrielle. La question environnementale, et plus précisément l’écologie industrielle, constituerait ainsi une nouvelle étape dans le processus évolutif de l’économie industrielle. Mobilisant de nouveaux courants de pensée (théorie des conventions, théorie des parties prenantes, districts industriels) et de nouvelles questions empiriques (étude du métabolisme industriel, valorisation des déchets, économie circulaire), l’écologie industrielle préfigure l’étude du changement tant annoncée pour l’économie industrielle Codes JEL : L11, L22, L25, P12, P23, Q57
Thermo-Kinetic Modelling and Analysis of the Simultaneous Hot Stamping and Quenching of EN AW-6016-T4 Sheet
Authors: Kumar Manoj
Published: May 2016

The aluminium alloy AW-6016-T4 sheet is the most widely used alloy for simple-shapeouter body parts for passenger vehicles at room temperature. However, for complex parts, such asthe B-pillar, the room temperature formability of AW-6016-T4 sheet is not sufficient. Simultaneoushot stamping and quenching is a viable alternative, but there is still limited information about theinfluence of process parameters on both the formability during the process and the part strength atthe end of the process. A combination of thermo-kinetic simulation and experiments were used toinvestigate the influence of process parameters in the simultaneous hot stamping and quenchingprocess.Increasing the heating rate from 1 to 100 K s-1 during heating to the solution heat treatment (SHT)temperature was found to have no significant influence on the UTS. However, a SHT time of 4 minis required to achieve highest strength by the end of the process chain. Increasing the amount ofdeformation and cooling rate after SHT have a positive influence on the finished part. PredictedDSC curves and Yield strength values from MatCalc were in good agreement with the experimentalresults.
Influence of Hot Rolling Condition on the Final Microstructure of Non-Oriented Electrical Steel Fe-3.2 wt.% Si
Authors: Stöcker Anett , Franke Armin , Hermann Harti , Kawalla Rudolf
Published: May 2016

In this paper the microstructure evolution of an iron-silicon alloy with 3.2 wt.% silicon throughout the manufacturing stages hot rolling, cold rolling and annealing is presented. Starting with a 35 mm thick feedstock, which was hot rolled to 1 mm, with different cooling conditions, the material was cold rolled to a final thickness of 0.3 mm and final annealed under same conditions to show the influence of the hot rolling on the texture and microstructure of the final annealed material.
Arvedi ESP for High-Quality Hot-Strip Production at Rizhao Steel
Authors: Linzer Bernd , Jungbauer Andreas
Published: May 2016

With five Arvedi ESP lines, Rizhao Steel in China is now focusing on the highly attractive local and export markets for high-quality, thin-gauge strip products. The first lines began operations in 2015.High-strength but lightweight car bodies, ultra-thin structures paired with the highest tensile strength – and all at the lowest production costs. Innovative processes are required in order to fulfil the demands of the car and metals industries. With precise thermo-mechanical rolling and rigorous temperature guidance in the narrowest possible operations windows Arvedi ESP opens the door to producing demanding steel grades in the shortest implementation times and at reduced alloying costs. Low operation costs are also provided by efficient induction heating and the resulting energy savings.This paper presents the ESP plant setup of Rizhao Steel as well as the training and support program. Additionally the potentials of AHSS production with ESP will be described by referencing the results of the first ESP plant in operation since 2009 at Arvedi Steel, Italy, and the ESP plants of Rizhao steel.
Numerical Investigation of a Process Control for the Roller Levelling Process Based on a Force Measurement
Authors: Grüber Markus , Hirt Gerhard
Published: May 2016

When processing conventional semi-finished metal strips, distinctive changes in the material properties along the strip length are unavoidable. The roller levelling process is sensitive to changes of those strip characteristics. Thus, a process control allowing for an online adaption of the roller levelling machine according to the actual strip characteristics is highly desirable. In order to enable a precise process layout, the calculation by the Finite Element Method (FEM) provides a suited strategy. Furthermore, the coupling of user-subroutines to an FE code offers the possibility to implement and test respective control strategies. This work proposes a control strategy that is based on a force measurement in the first load triangle of a levelling machine. A first FE model including a feedback control is used to calculate the dependence between the force in the first load triangle and the roll intermesh in the last load triangle leading to a flat sheet. The results are transferred to meta models – so called control curves – that give a direct relationship between the measured force and the roll intermesh. Within a second FE setup a feed-forward control based on these control curves is implemented and the proposed control strategy is investigated for varying yield strengths along the strip length. Thus, the time consuming FE simulations that are necessary to obtain the control curves are decoupled from the actual levelling process. According to the obtained results, the introduced approach is able to improve the sheet flatness for thin sheets when a change in the material properties occurs.
Development of Rolling Technology for an Iron-Based Shape-Memory-Alloy
Authors: Leinenbach Christian , Czaderski Christoph , Michels Julien , Graf Marcel , Kawalla Rudolf
Published: May 2016

Low cost Fe-Mn-Si based shape memory alloys (SMA) have drawn much attention during the last two decades as a cost-effective alternative to the expensive Ni-Ti based SMA. In particular, the alloy Fe-17Mn-5Si-10Cr-4Ni-1(V,C) (mass%), which has been developed at Empa shows very promising properties with regard to potential commercial applications in civil and mechanical engineering. This alloy has a higher reverse transformation temperature and larger thermal hysteresis in comparison to the Ni-Ti based alloys, which is adequate for producing stable recovery stresses at room temperature. Furthermore, recovery stresses of up to 300 MPa after heating to only 160°C can be achieved without so-called ‘training’ treatment. Furthermore, the alloy can be easily and cost effectively produced under standard air melting and casting conditions. For availability of these heavily microstructure dependent skills for civil and mechanical engineering, e.g. as prestressing elements in concrete structures or coupling/clamping devices, a process chain for manufacturing is necessary. Therefore, a hot and cold rolling technology for strip production with thermal heat treatment processes was developed at TU Bergakademie on base of experimental simulation results. The last one helps to understand the dependencies of deformation parameters, the deformation behavior and their influence to the microstructure evolution in correlation to the recovery.This paper discusses the basic material properties, recovery stress formation behavior and finally the feasibility of the alloy as reinforcing elements in civil engineering applications by using a rolling technology for flat products.
Seasonal variation in the frequency of myocardial infarction diagnosed in a large emergency department of a European country with a temperate climate
Authors: Lippi Giuseppe , Mattiuzzi Camilla , Cervellin Gianfranco
Published: May 2016

Previous studies at different latitudes showed that acute myocardial infarction (AMI) exhibits a seasonal variation, with higher frequency in spring and winter. We conducted a retrospective analysis to verify whether the frequency of AMI cases diagnosed in the emergency department (ED) may follow a seasonal pattern in a European country with a temperate climate. A retrospective analysis was performed in the hospital database of the University Hospital of Parma (northwestern Italy), to retrieve the total number of AMI cases diagnosed in the ED during the entire year 2010. The search for AMI cases was conducted using both ICD-9 codes and related diagnostic terms. The seasonality was defined according to the typical equinoxes and solstices at the latitude of the study. A total of 83,919 patients visited the ED of the University Hospital of Parma during the year 2010, 502 (0.6%) of whom with a final diagnosis of AMI (mean age, 73±14 years; 188 women and 314 men). The largest frequency of AMIs was observed in autumn (n=148; 29%), followed by winter (n=136, 27%), whereas the lowest frequencies were recorded in spring (n=110; 22%) and summer (n=108; 22%). The difference in frequency distribution of AMI cases across the four seasons of the year was found to be statistically significant (P<0.001), and this trend was independent from sex and age. Compared to the summer period (i.e., the season with the lowest frequency of AMI cases), the relative risk (RR) for AMI was significantly higher in autumn (1.37; 95% CI, 1.15-1.63; P<0.001) and winter (1.26; 95% CI, 1.05-1.51; P=0.013), but not in spring (1.02; 95% CI, 0.83-1.24; P=0.857). Compared to the spring period, the RR for AMI was found also to be significantly higher in autumn (1.34; 95% CI, 1.13-1.60; P<0.001) and winter (1.24; 95% CI, 1.03-1.48; P=0.021).
Evolution of the microbiological profile of vacuum-packed ricotta salata cheese during shelf-life
Authors: Casti Daniele , Scarano Christian , Pala Carlo , Cossu Francesca , Lamon Sonia , Spanu Vincenzo , Ibba Michela , Mocci Anna Maria , Tedde Francesco , Nieddu Gavino , Spanu Carlo , De Santis Enrico Pietro Luigi
Published: May 2016

Ricotta salata cheese is a salted variety of ricotta traditionally made in Sardinia (Italy) from the whey remaining after the production of Pecorino Romano protected designation of origin or other sheep milk cheeses. Ricotta salata cheese is very critical for the possible growth of pathogenic and spoilage microorganisms. Sporadic cases of listeriosis associated with ricotta salata cheese have been reported over recent years. The objective of the present study was to assess the evolution of spoilage and pathogen microorganism of vacuum-packed ricotta salata cheese during the entire product shelf-life. The durability study was conducted on 18 vacuum-packed ricotta salata cheese samples analysed at the beginning of the shelf-life and after 60 and 90 days of refrigerated storage. Pathogens as Listeria monocytogenes and Bacillus cereus were never detected. During shelf-life total bacterial counts ranged between 7.90±0.64 and 9.19±0.58 CFU g-1 on the rind and between 2.95±0.68 and 4.27±1.10 CFU g-1 in the inner paste, while Enterobacteriaceae ranged between 4.22±0.66 and 5.30±0.73 CFU g-1 on the rind and 3.13±1.80 and 2.80±0.88 CFU g-1 in the inner paste. By considering the technology used, the intrinsic properties and the almost total absence of competing microflora, ricotta salata cheese can support the growth of spoilage and pathogen microorganisms originating from the processing environment. The high level of total bacterial counts and Enterobacteriaceae observed both on the rind and in the inner paste suggests contamination of the product from the processing environment. Therefore, a strict implementation of hygiene during processing is essential in order to reduce the load of environmental contaminants that may grow during refrigerated storage.
Central neurogenic hyperventilation related to post-hypoxic thalamic lesion in a child
Authors: Gençpinar Pinar , Karaali Kamil , Haspolat Şenay , Dursun Oğuz
Published: May 2016

Central neurogenic hyperventilation (CNH) is a rare clinical condition, whose mechanism is still unclear. Here, we report a 3-year-old male patient, who had bilateral thalamic, putaminal and globus pallideal infarction resulted in CNH without brainstem involvement. This case may illustrate a possible role for the thalamus in regulating ventilation.
Antioxidant effect of Mn2+ on capacitation and acrosome reaction of fresh and chilled cattle bull semen
Authors: Bansal Amrit Kaur , Cheema Ranjna Sundhey , Gandotra Vinod Kumar
Published: May 2016

The aim of this paper was to investigate the antioxidant effect of Mn2+ (200 mM) on the sperm capacitation and acrosome reaction of fresh and chilled cattle bull semen. It has been found that Mn2+ supplementation improves (P≤0.05) the motility at 0, 2, 4 and 6 h of incubation. MDA (malondialdehyde), end product of lipid peroxidation, decreases significantly (P≤0.05) with the supplementation of manganese at 0- and 6-hr of incubation both in fresh and chilled semen. Manganese also increases acrosome reaction significantly (P≤0.05) both in fresh and chilled semen at 0, 4 and 6 h of incubation. Therefore, our findings suggest the role of Mn2+supplementation in improving the quality of cattle bull semen by its scavenging property i.e. reduction in the production of reactive oxygen species during its storage at 4°C or incubation at 37°C for capacitation.
Prediction of the Risk for Essential Hypertension among Carriers of C825T Genetic Polymorphism of G Protein β3 (GNB3) Gene
Authors: Hemimi Neveen Salah El Din , Mansour Amal A. , Abdelsalam Mona Mohamed
Published: May 2016

Background

The guanine nucleotide-binding protein beta polypeptide 3 (GNB3) 825T allele encodes a product that enhances the activation of heterotrimeric G proteins, which is associated with the occurrence of the splice variant Gβ3 s that could play a role in vascular reactivity and hyperproliferation of smooth muscle cells, that makes such proteins attractive candidate gene products for susceptibility to essential hypertension (EH).

Objective

To predict the risk for EH in individuals with C825T genetic polymorphism of G protein β3 gene.

Methods

The study consisted of 222 normotensive individuals and 216 hypertensive patients. Individuals were genotyped for C825T genetic polymorphism of G protein β3 gene rs5443 by using restriction fragment length polymorphism.

Results

Frequencies of C and T alleles were 58.1% and 41.9%, respectively, in the control group compared with 47.7% and 52.3%, respectively, in the hypertensive group. The carriers of rs5443 (T) allele exhibited a significant greater risk for EH compared with the carriers of rs5443 (C) allele (odds ratio = 1.5, 95% confidence interval = 1.2–2.0).

Conclusion

T allele is a risk factor for EH in the Egyptian population, which may be used as a prognostic and a therapeutic target of prophylaxis.
Novel Symplectic Discrete Singular Convolution Method for Hamiltonian PDEs
Authors: Cai Wenjun , Zhang Huai , Wang Yushun
Published: May 2016

This paper explores the discrete singular convolution method for Hamiltonian PDEs. The differential matrices corresponding to two delta type kernels of the discrete singular convolution are presented analytically, which have the properties of high-order accuracy, bandlimited structure and thus can be excellent candidates for the spatial discretizations for Hamiltonian PDEs. Taking the nonlinear Schrödinger equation and the coupled Schrödinger equations for example, we construct two symplectic integrators combining this kind of differential matrices and appropriate symplectic time integrations, which both have been proved to satisfy the square conservation laws. Comprehensive numerical experiments including comparisons with the central finite difference method, the Fourier pseudospectral method, the wavelet collocation method are given to show the advantages of the new type of symplectic integrators.
Evaluation of Commercially Available Assays for Diagnosis of Acute Dengue in Schoolchildren During an Epidemic Period in Medellin, Colombia
Authors: Piedrahita Leidy D. , Agudelo Ivony Y. , Trujillo Andrea I. , Ramírez Ruth E. , Osorio Jorge E. , Restrepo Berta N.
Published: May 2016

During an active surveillance study in school children in Medellin, we assessed the performance of two diagnostic strategies for dengue virus. A total of 41 patients with suspected dengue acute infection were evaluated. Diagnostic strategies consisted of one combining Panbio® Dengue virus IgM and IgG Capture ELISAs (enzyme-linked immunosorbent assays) with reverse transcriptase polymerase chain reaction (RT-PCR) and another using a commercial rapid SD Bioline Dengue Duo (IgG/IgM + NS1 Ag) test. These two strategies were compared with the enzyme-linked immunospot microneutralization test (ELISPOT-MNT). The sensitivity and specificity were 53.9% and 80.0% for the combination of Panbio® ELISAs and RT-PCR tests, and 30.8% and 73.3% for the SD Bioline Duo test, respectively. ELISPOT-MNT detected 16.4% additional cases and revealed the presence of neutralizing antibodies in all the acute samples, evidencing that they were all secondary infections. In contrast, Panbio® and SD Dengue Duo rapid tests only classified 23.0% and 26.9% of the cases as secondary dengue infections, respectively. Cohen's kappa coefficient and McNemar's association tests demonstrated a significant disagreement between the two diagnostic strategies and ELISPOT-MNT. Overall, these results evidence the relatively poor performances of commercial assays for the diagnosis of acute and secondary dengue infections, compared with ELISPOT-MNT, and raise concern about the accuracy of these assays for the diagnostic of dengue in endemic areas.
Lethality of First Contact Dysentery Epidemics on Pacific Islands
Authors: Shanks G. Dennis
Published: May 2016

Infectious diseases depopulated many isolated Pacific islands when they were first exposed to global pathogen circulation from the 18th century. Although the mortality was great, the lack of medical observers makes determination of what happened during these historical epidemics largely speculative. Bacillary dysentery caused by Shigella is the most likely infection causing some of the most lethal island epidemics. The fragmentary historical record is reviewed to gain insight into the possible causes of the extreme lethality that was observed during first-contact epidemics in the Pacific. Immune aspects of the early dysentery epidemics and postmeasles infection resulting in subacute inflammatory enteric disease suggest that epidemiologic isolation was the major lethality risk factor on Pacific islands in the 19th century. Other possible risk factors include human leukocyte antigen homogeneity from a founder effect and pathogen-induced derangement of immune tolerance to gut flora. If this analysis is correct, then Pacific islands are currently at no greater risk of emerging disease epidemics than other developing countries despite their dark history.
Study of wind forces on low-rise hip-roof building
Authors: Jameel A. , Irtaza H. , Javed M.A.
Published: May 2016

A comprehensive numerical study of wind effects using Computational Fluid Dynamics (CFD) techniques on the low-rise hipped roof building is presented in this paper. Two Reynolds Averaged Navier–Stokes Equations (RANS) techniques such as the Standard k -e turbulence model and the Renormalization group (RNG) k - ε turbulence model were adopted in this study to predict the wind loads and the flow patterns around the hip-roof building. The computed wind pressure coefficients on the roof of the hip-roof buildings were compared with the wind-tunnel data. It was found that the results obtained using RNG k - ε turbulence model are in good agreement with that of the wind-tunnel data than the Standard k - ε turbulence model. It was also found that the CFD techniques are an effective and alternative tool, less time consuming, easy-to-handle, as well as low cost approach for evaluation of wind effects in comparison to wind-tunnel experiments, using the above turbulence models and with the available resources.Keywords: CFD, Computational Fluid Dynamics, Wind force, Hip-roof building, Low-rise building, RANS approach, Wind Engineering.
What is Known about Corpus Callosum Prenatally?
Authors: Merz E
Published: May 2016

The corpus callosum is the main commissure of the fetal brain and can be displayed with two-dimensional (2D) and threedimensional (3D) ultrasound. However, only 3D ultrasound provides the operator with the possibility to adjust the three orthogonal planes of the brain in that way that the entire corpus callosum is shown precisely in the median plane.

The aim of this article is to provide the most recent information on the assessment of the fetal corpus callosum by means of 3D ultrasound. Different topics are highlighted, such as advantage of 3D ultrasound over 2D ultrasound, indications for displaying the fetal corpus callosum, demonstration of the normal and abnormal corpus callosum and biometric measurements of the fetal corpus callosum by 3D ultrasound. Furthermore the question is raised whether fetal magnetic resonance imaging (MRI) can give additional information to the 3D ultrasound examination and whether the diagnosis resulting from 3D neurosonography gives us the chance for a better counseling of parents who are confronted with the diagnosis of a fetal corpus callosum pathology.

How to cite this article

Merz E, Pashaj S. What is Known about Corpus Callosum Prenatally? Donald School J Ultrasound Obstet Gynecol 2016;10(2):163-169.
Simulating the SOA formation of isoprene from partitioning and aerosol phase reactions in the presence of inorganics
Authors: Beardsley Ross L. , Jang Myoseon
Published: May 2016

Abstract. The secondary organic aerosol (SOA) produced by the photooxidation of isoprene with and without inorganic seed is simulated using the Unified Partitioning Aerosol Phase Reaction (UNIPAR) model. Recent work has found the SOA formation of isoprene to be sensitive to both aerosol acidity ([H+], mol L−1) and aerosol liquid water content (LWC) with the presence of either leading to significant aerosol phase organic mass generation and large growth in SOA yields (YSOA). Classical partitioning models alone are insufficient to predict isoprene SOA formation due to the high volatility of photooxidation products and sensitivity of their mass yields to variations in inorganic aerosol composition. UNIPAR utilizes the chemical structures provided by a near-explicit chemical mechanism to estimate the thermodynamic properties of the gas phase products, which are lumped based on their calculated vapor pressure (eight groups) and aerosol phase reactivity (six groups). UNIPAR then determines the SOA formation of each lumping group from both partitioning and aerosol phase reactions (oligomerization, acid-catalyzed reactions and organosulfate formation) assuming a single homogeneously mixed organic–inorganic phase as a function of inorganic composition and VOC ∕ NOx (VOC – volatile organic compound). The model is validated using isoprene photooxidation experiments performed in the dual, outdoor University of Florida Atmospheric PHotochemical Outdoor Reactor (UF APHOR) chambers. UNIPAR is able to predict the experimental SOA formation of isoprene without seed, with H2SO4 seed gradually titrated by ammonia, and with the acidic seed generated by SO2 oxidation. Oligomeric mass is predicted to account for more than 65 % of the total organic mass formed in all cases and over 85 % in the presence of strongly acidic seed. The model is run to determine the sensitivity of YSOA to [H+], LWC and VOC ∕ NOx, and it is determined that the SOA formation of isoprene is most strongly related to [H+] but is dynamically related to all three parameters. For VOC ∕ NOx  >  10, with increasing NOx both experimental and simulated YSOA increase and are found to be more sensitive to [H+] and LWC. For atmospherically relevant conditions, YSOA is found to be more than 150 % higher in partially titrated acidic seeds (NH4HSO4) than in effloresced inorganics or in isoprene only.
The impact of meteorological analysis uncertainties on the spatial scales resolvable in CO2 model simulations
Authors: Polavarapu Saroja M. , Neish Michael , Tanguay Monique , Girard Claude , de Grandpre Jean , Semeniuk Kirill , Gravel Sylvie , Ren Shuzhan , Roche Sébastien , Chan Douglas , Strong Kimberly
Published: May 2016

Abstract. A new model for greenhouse gas transport has been developed based on Environment and Climate Change Canada's operational weather and environmental prediction models. When provided with realistic posterior fluxes for CO2, the CO2 simulations compare well to NOAA's CarbonTracker fields, and to near surface continuous measurements, columns from the Total Carbon Column Observing Network (TCCON), and NOAA aircraft profiles. This coupled meteorological and tracer transport model is used to study the atmospheric modulation of CO2 transport. The predictability of CO2 due to initial state sensitivity is shorter than that for the temperature field but is consistent with the predictability of the wind fields. However, when broken down into spatial scales, CO2 has predictability at the very largest scales due to long time scale memory in surface CO2 fluxes as well as in land and ocean surface forcing of meteorological fields. The predictability due to the land and ocean surface is most evident in boreal summer when biospheric uptake produces large spatial gradients in the CO2 field. Predictability errors provide an upper limit for errors arising solely from the use of uncertain meteorological analyses. When considering meteorological analysis errors, CO2 can be defined only on large scales. Thus, there is a spatial scale below which information cannot be obtained simply due to the fact that meteorological analyses are imperfect. Compared to the spatial scales resolvable in the context of imperfect atmospheric analyses, the differences between two sets of posterior fluxes are resolvable only for very large scales. Similarly, the impact of convective tracer transport exceeds that due to atmospheric analysis errors for only the largest spatial scales.
Quantifying the Loss of Processed Natural Gas Within California's South Coast Air Basin Using Long-term Measurements of Ethane and Methane
Authors: Wunch Debra , Toon Geoffrey C. , Hedelius Jacob , Vizenor Nicholas , Roehl Coleen M. , Saad Katherine M. , Blavier Jean-François L. , Blake Donald R. , Wennberg Paul O.
Published: May 2016

Abstract. California's South Coast Air Basin (SoCAB) is a region in which the top-down methane emissions are underestimated by the bottom-up inventories. To provide insight into the sources of the discrepancy, we analyse a record of atmospheric trace gas total column abundances in the SoCAB starting in the late 1980s. The gases measured include ethane and methane and provide insight into the sources of the excess methane found in the SoCAB. The early few years of the record show a rapid decline in ethane emissions at a much faster rate than decreasing vehicle exhaust or natural gas and crude oil production can explain. Between 2010 and 2015, ethane emissions have grown gradually from 13 ± 4.5 Gg · yr−1 to 25.8 ± 3.9 Gg · yr−1, which is in contrast to the steady production of natural gas liquids over that time. Our methane emissions record begins in 2012 and shows an increase between 2012 and 2015 from 380 ± 78 Gg · yr−1 to 448 ± 91 Gg · yr−1. Since 2012, ethane to methane ratios in the natural gas withdrawn from a storage facility within the SoCAB have been increasing; these ratios are tracked in our atmospheric measurements with about half of the rate of increase. From this, we infer that about half of the excess methane in the SoCAB between 2012–2015 is attributable to losses from the natural gas infrastructure.
A modified impulse-response representation of the global response to carbon dioxide emissions
Authors: Millar Richard J. , Nicholls Zebedee R. , Friedlingstein Pierre , Allen Myles R.
Published: May 2016

Abstract. Projections of the response to anthropogenic emission scenarios, evaluation of some greenhouse gas metrics and estimates of the social cost of carbon, often require a simple model that links emissions of carbon dioxide CO2 to atmospheric concentrations and global temperature changes. An essential requirement of such a model is to reproduce the behaviour of more complex models as well as an ability to sample their range of response in a transparent, accessible and reproducible form. Here we adapt the simple model of the Intergovernmental Panel on Climate Change 5th Assessment Report (IPCC-AR5) to explicitly represent the state-dependence of the CO2 airborne fraction and reproduce several idealised experiments performed with more complex models. We find that a simple linear increase in 100-year integrated airborne fraction with cumulative carbon uptake and global temperature change is both necessary and sufficient to represent the response of the climate system to CO2 on a range of timescales and under a range of experimental designs. Quantified ranges of uncertainty (analogous to current assessed ranges in Equilibrium Climate Sensitivity and Transient Climate Response) in integrated airborne fraction over the 21st century under a representative mitigation scenario, and an assessed range in how much this quantity may have changed relative to pre-industrial conditions, would be valuable in future scientific assessments.
Validation of ACE-FTS version 3.5 NOy species profiles using correlative satellite measurements
Authors: Sheese Patrick E. , Walker Kaley A. , Boone Chris D. , McLinden Chris A. , Bernath Peter F. , Bourassa Adam E. , Burrows John P. , Degenstein Doug A. , Funke Bernd , Fussen Didier , Manney Gloria L. , McElroy C. Thomas , Murtagh Donal , Randall Cora E. , Raspollini Piera , Rozanov Alexei , Russell III James M. , Suzuki Makoto , Shiotani Masato , Urban Joachim , von Clarmann Thomas , Zawodny Joseph M.
Published: May 2016

Abstract. The ACE-FTS (Atmospheric Chemistry Experiment – Fourier Transform Spectrometer) instrument on the Canadian SCISAT satellite, which has been in operation for over 12 years, has the capability of deriving stratospheric profiles of many of the NOy (NO + NO2 + NO3 + 2 × N2O5 + HNO3 + HNO4 + ClONO2 + BrONO2) species. Version 2.2 of ACE-FTS NO, NO2, HNO3, N2O5, and ClONO2 have previously been validated, and this study compares the most recent version (v3.5) of these five ACE-FTS products to spatially and temporally coincident measurements from other satellite instruments–GOMOS, HALOE, MAESTRO, MIPAS, MLS, OSIRIS, POAM III, SAGE III, SCIAMACHY, SMILES, and SMR. For each ACE-FTS measurement, a photochemical box model was used to simulate the diurnal variations of the NOy species and the ACE-FTS measurements were scaled to the local times of the coincident measurements. The comparisons for all five species show good agreement with correlative satellite measurements. For NO in the altitude range of 25–50 km, the instrument-averaged mean relative differences are on the order of 0 to −10 %. They are approximately −10 % at 30–40 km for NO2, they are within ±7 % at 8–30 km for HNO3, they are better than −7% at 21–34 km for local morning N2O5, and better than −8 % at 21–34 km for ClONO2. Where possible, the variations in the mean differences due to changes in the comparison local time and latitude are also discussed.
High-resolution forest carbon flux mapping and monitoring in the Pacific Northwest with time since disturbance and disturbance legacies inferred from remote sensing and inventory data
Authors: Gu Huan , Williams Christopher A. , Ghimire Bardan , Zhao Feng , Huang Chengquan
Published: May 2016

Abstract. Assessment of forest carbon storage and uptake is central to understanding the role forests play in the global carbon cycle and policy-making aimed at mitigating climate change. Current U.S. carbon stocks and fluxes are monitored and reported at fine-scale regionally, or coarse-scale nationally. We proposed a new methodology of quantifying carbon uptake and release across forested landscapes in the Pacific Northwest (PNW) at a fine scale (30 m) by combining remote-sensing based disturbance year, disturbance type, and aboveground biomass with forest inventory data in a carbon modelling framework. Time since disturbance is a key intermediate determinant that aided the assessment of disturbance-driven carbon emissions and removals legacies. When a recent disturbance was detected, time since disturbance can be directly determined by remote sensing-derived disturbance products; and if not, time since last stand-clearing was inferred from remote sensing-derived 30 m biomass map and field inventory-derived species-specific biomass regrowth curves. Net ecosystem productivity (NEP) was further mapped based on carbon stock and flux trajectories that described how NEP changes with time following harvest, fire, or bark beetle disturbances of varying severity. Uncertainties from biomass map and forest inventory data were propagated by probabilistic sampling to provide a probabilistic, statistical distribution of stand age and NEP for each forest pixel. We mapped mean, standard deviation and statistical distribution of stand age and NEP at 30 m in the PNW region. Our map indicated a net ecosystem productivity of 5.2 Tg C y−1 for forestlands circa 2010 in the study area, with net uptake in relatively mature (> 24 year old) forests (13.6 Tg C y−1) overwhelming net negative NEP from tracts that have seen recent harvest (−6.4 Tg C y−1), fires (−0.5 Tg C y−1), and bark beetle outbreaks (−1.4 Tg C y−1). The approach will be applied to forestlands in other regions of the conterminous U.S. to advance a more comprehensive monitoring, mapping and reporting the carbon consequences of forest change across the U.S.
Seasonal and vertical variations in soil CO2 production in a beech forest: an isotopic flux-gradient approach
Authors: Delogu Emilie , Longdoz Bernard , Plain Caroline , Epron Daniel
Published: May 2016

Abstract. Soil CO2 efflux results from the transport of CO2 from several respiration sources within the soil profile. A flux – gradient approach (FGA) was used to assess the vertical profile of CO2 production (P_CO2) and its isotopic composition (δ13P_CO2) from the measurement of the vertical profile of CO2 concentration and CO2 isotopic composition combined with soil CO2 and δ13CO2 effluxes. Variations in P_CO2 and δ13P_CO2 within different soil layers were analyzed at different time scales. In the first soil layers, P_CO2 was probably underestimated and δ13P_CO2 overestimated when CO2 transport was not solely diffusive. At the seasonal scale, a vertical gradient of P_CO2 temperature sensitivity was observed. At the within-day scale, variations in soil temperature were too weak to explain the strong variations in P_CO2. At the daily time scale, δ13P_CO2 of sources located between −10 and −20 cm depth was well correlated with the canopy inherent water use efficiency (IWUE) measured the day before. The strong correlation with IWUE argues in favor of an actual connection between canopy activity and soil autotrophic production. Moreover, including SWC of the current day as a second variable improved the linear regression between δ13P_CO2 and IWUE of the previous day, together explaining 76 % of the daily fluctuations in δ13P_CO2. This highlights the actual contribution of both autotrophic and heterotrophic sources to soil P_CO2. The method used gave consistent and promising results even if we could not disentangle the respective contribution of autotrophic and heterotrophic sources to CO2 production as the differences in their isotopic composition were too small and fluctuated too much. In addition, CO2 transport by turbulent advection and dispersion will need to be considered for the top soil layer.
Collateral transgression of planetary boundaries due to climate engineering by terrestrial carbon dioxide removal
Authors: Heck Vera , Donges Jonathan F. , Lucht Wolfgang
Published: May 2016

Abstract. The planetary boundaries framework as proposed by Rockström et al. (2009) provides guidelines for defining thresholds in environmental variables. Their transgression is likely to result in a shift in Earth system functioning away from the relatively stable Holocene state. As the climate change boundary is already transgressed, several climate engineering methods are discussed, aiming at a reduction of atmospheric carbon concentrations to control the Earth's energy balance. Terrestrial carbon dioxide removal (tCDR) via afforestation or bioenergy production with carbon capture and storage are part of most climate change mitigation scenarios that limit global warming to less than 2 °C. We analyse the co-evolutionary interaction of societal interventions via tCDR and the natural dynamics of the Earth's carbon cycle. Applying a conceptual modelling framework, we analyse how societal monitoring and management of atmospheric CO2 concentrations with the aim of staying within a "safe" level of global warming might influence the state of the Earth system with respect to other carbon-related planetary boundaries. Within the scope of our approach, we show that societal management of atmospheric carbon via tCDR can lead to a transgression of the planetary boundaries of land system change and ocean acidification. Our analysis indicates that the opportunities to remain in a desirable region within carbon-related planetary boundaries depend critically on the sensitivity and strength of the tCDR management system, as well as underlying emission pathways. While tCDR has the potential to ensure the Earth system's persistence within a carbon safe operating space under low emission pathways, this potential decreases rapidly for medium to high emission pathways.
A Joint Global Carbon Inversion System Using Both CO2 and CO2 Atmospheric Concentration Data
Authors: Chen Jing M. , Mo Gang , Deng Feng
Published: May 2016

Abstract. Observations of 13CO2 at 73 sites compiled in the GLOBALVIEW database are used for an additional constraint in a global atmospheric inversion of the surface CO2 flux using CO2 observations at 210 sites (62 collocated with 13CO2 sites) for the 2002–2004 period for 39 land regions and 11 ocean regions. This constraint is implemented using prior CO2 fluxes estimated with a terrestrial ecosystem model and an ocean model. These models simulate 13CO2 discrimination rates of terrestrial photosynthesis and ocean-atmosphere diffusion processes. In both models, the 13CO2 disequilibrium between fluxes to and from the atmosphere is considered due to the historical change in atmospheric 13CO2 concentration. This joint inversion system using both 13CO2 and CO2 observations is effectively a double deconvolution system with consideration of the spatial variations of isotopic discrimination and disequilibrium. This 13CO2 constraint on the inversion considerably reduces the total land carbon sink from 3.40 ± 0.84 to 2.78 ± 0.76 Pg C y−1 but increases the total oceanic carbon sink from 1.48 ± 0.40 to 2.26 ± 0.35 Pg C y−1. This constraint also changes the spatial distribution of the carbon sink. The largest sink increase occurs in Amazon, while the largest source increases are in southern Africa, and Asia, where CO2 data are sparse. Through a case study, in which the spatial distribution of the annual 13CO2 discrimination rate over land is ignored by treating it as a constant at the global average of −14.1 ‰, the spatial distribution of the inverted CO2 flux over land was found to be significantly modified (up to 15 % for some regions). The uncertainties in our disequilibrium flux estimation are 11.2 PgC y−1 ‰ and 16.3 Pg C y−1 ‰ for land and ocean, respectively. These uncertainties induced uncertainties of 0.47 Pg C y−1 and 0.54 Pg C y−1 in the inverted CO2 fluxes for land and ocean, respectively. Our joint inversion system is therefore useful for improving the partitioning between ocean and land sinks and the spatial distribution of the inverted carbon flux.
Crop-specific seasonal estimates of irrigation-water demand in South Asia
Authors: Biemans Hester , Siderius Christian , Mishra Ashok , Ahmad Bashir
Published: May 2016

Abstract. Especially in the Himalayan headwaters of the main rivers in South Asia, shifts in runoff are expected as a result of a rapidly changing climate. In recent years, our insight into these shifts and their impact on water availability has increased. However, a similar detailed understanding of the seasonal pattern in water demand is surprisingly absent. This hampers a proper assessment of water stress and ways to cope and adapt. In this study, the seasonal pattern of irrigation-water demand resulting from the typical practice of multiple cropping in South Asia was accounted for by introducing double cropping with monsoon-dependent planting dates in a hydrology and vegetation model. Crop yields were calibrated to the latest state-level statistics of India, Pakistan, Bangladesh and Nepal. The improvements in seasonal land use and cropping periods lead to lower estimates of irrigation-water demand compared to previous model-based studies, despite the net irrigated area being higher. Crop irrigation-water demand differs sharply between seasons and regions; in Pakistan, winter (rabi) and monsoon summer (kharif) irrigation demands are almost equal, whereas in Bangladesh the rabi demand is  ∼  100 times higher. Moreover, the relative importance of irrigation supply versus rain decreases sharply from west to east. Given the size and importance of South Asia improved regional estimates of food production and its irrigation-water demand will also affect global estimates. In models used for global water resources and food-security assessments, processes like multiple cropping and monsoon-dependent planting dates should not be ignored.