bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparisons of continuous atmospheric CH4, CO2 and N2O measurements – results of InGOS travelling instrument campaign at Mace Head
Authors: Vardag S. N. , Hammer S. , O'Doherty S. , Spain T. G. , Wastine B. , Jordan A. , Levin I.
Published: April 2014

Abstract. A two-month measurement campaign with a Fourier Transform InfraRed (FTIR) analyser as a Travelling Comparison Instrument (TCI) was performed at the AGAGE and WMO GAW station Mace Head, Ireland. The aim was to evaluate the compatibility of atmospheric CH4, CO2 and N2O measurements of the routine station instrumentation, consisting of a gas chromatograph (GC-MD) for CH4 and N2O as well as a cavity ring-down spectroscopy (CRDS) system for CH4 and CO2. The advantage of a TCI approach for quality control is that the comparison covers the entire ambient air measurement system, including the sample intake system and the data evaluation process. For initial quality and performance control the TCI was run in parallel to the Heidelberg GC (GC-HEI) before and after the measurement campaign at Mace Head. Median differences between the GC-HEI and the TCI were well within the WMO Inter Laboratory Compatibility (ILC) target for all three greenhouse gases. At Mace Head, the median difference between the GC-MD and the TCI were −0.04 nmol mol−1 for CH4 and −0.37 nmol mol−1 for N2O. For N2O a similar difference (−0.40 nmol mol−1) was found when measuring surveillance or working gas cylinders with both instruments. This suggests that the difference observed in ambient air originates from a calibration offset that could partly be due to a difference between the WMO N2O X2006a scale used for the TCI and the SIO-1998 scale used at Mace Head and in the whole AGAGE network. Median differences between the CRDS G1301 and the TCI at Mace Head were 0.12 nmol mol−1 for CH4 and 0.14 μmol mol−1 for CO2 (CRDS G1301 − TCI). The difference between both instruments for CO2 could not be explained, as direct measurements of calibration gases show no such difference. The CH4 differences between the TCI, the GC-MD and the CRDS G1301 at Mace Head are smaller than the WMO Inter Laboratory compatibility (ILC) target (WMO, 2009), while this is not the case for CO2 and N2O. During the campaign it was also demonstrated that the new optical instrumentation allows detection of very small vertical CO2 and CH4 gradients, here between 10 m a.g.l. and 25 m a.g.l. This provides a new opportunity of evaluating greenhouse gases gradients in terms of regional fluxes.
Nitrate source identification using its isotopic ratios in combination with a Bayesian isotope mixing model in the Baltic Sea
Authors: Korth F. , Deutsch B. , Frey C. , Moros C. , Voss M.
Published: April 2014

Abstract. Nitrate (NO3−) is the major nutrient responsible for coastal eutrophication worldwide and its production is related to intensive food production and fossil-fuel combustion. In the Baltic Sea NO3−inputs have increased four-fold over the last decades and now remain constantly high. NO3− source identification is therefore an important consideration in environmental management strategies. In this study focusing on the Baltic Sea, we used a method to estimate the proportional contributions of NO3− from atmospheric deposition, N2 fixation, and runoff from pristine soils as well as from agricultural land. Our approach combines data on the dual isotopes of NO3− (δ15N-NO3− and δ18O-NO3−) in winter surface waters with a Bayesian isotope mixing model (Stable Isotope Analysis in R, SIAR). Based on data gathered from 46 sampling locations over the entire Baltic Sea, the majority of the NO3− in the southern Baltic was shown to derive from runoff from agricultural land (30–70%), whereas in the northern Baltic, i.e., the Gulf of Bothnia, NO3− originates from nitrification in pristine soils (47–100%). Atmospheric deposition accounts for only a small percentage of NO3− levels in the Baltic Sea, except for contributions from northern rivers, where the levels of atmospheric NO3− are higher. An additional important source in the central Baltic Sea is N2 fixation by diazotrophs, which contributes 31–62% of the overall NO3− pool at this site. The results obtained with this method are in good agreement with source estimates based upon δ15N values in sediments and a three-dimensional ecosystem model, ERGOM. We suggest that this approach can be easily modified to determine NO3− sources in other marginal seas or larger near-coastal areas where NO3− is abundant in winter surface waters when fractionation processes are minor.
Geochronological reconsideration of the eastern European key loess section at Stayky in Ukraine
Authors: Kadereit A. , Wagner G. A.
Published: April 2014

Abstract. Event-stratigraphical correlations between regional terrestrial sedimentary archives and marine or ice-core records that provide climate history are highly desirable for a deeper understanding of the effects of global climate change. However, such correlations are not simple, as the terrestrial records tend to be floating and fragmentary, and usually show varying sedimentation rates. Therefore, a reliable chronometric framework is a prerequisite for any event stratigraphy involving terrestrial archives. We propose that the age model underlying the event-stratigraphical approach for the eastern European key loess section at Stayky in Ukraine needs revision. Here we explore why it is unlikely that the Middle Pleniglacial Vytachiv Soil developed during Greenland interstadial (GIS) 8, and why the embryonic soils in the upper part of the Upper Pleniglacial part of the loess section most likely post-date the Heinrich 2 event. As a consequence, the revised age-model challenges the earlier suggested correlation of the suite of incipient soils above the Vytachiv Soil with Greenland Interstadials, which was supposed to start with GIS7 but for which matching from after GIS5 seems more likely. The revised chronology suggests that the transition from Middle to Upper Pleniglacial environmental conditions at the eastern European key section occurred during the final phase of marine isotope stage (MIS) 3. Thus, the picture appears to be in accordance with that of the western European key section at Nussloch. This points to a common driver of palaeo-environmental change in both regions, such as early late glacial maximum (LGM) advances of the Arctic ice shield or changes of the North Atlantic circulation and sea-ice distribution associated with changes in the palaeowind field relevant to aeolian loess deposition and soil formation. To test and substantiate the alternative age model, more chronologies for well-stratified loess sections throughout the European loess belt are required.
Ensemble meteorological reconstruction using circulation analogues of 1781–1785
Authors: Yiou P. , Boichu M. , Vautard R. , Vrac M. , Jourdain S. , Garnier E. , Fluteau F. , Menut L.
Published: April 2014

Abstract. This paper uses a method of atmospheric flow analogues to reconstruct an ensemble of atmospheric variables (namely sea-level pressure, surface temperature and wind speed) between 1781 and 1785. The properties of this ensemble are investigated and tested against observations of temperature. The goal of the paper is to assess whether the atmospheric circulation during the Laki volcanic eruption (in 1783) and the subsequent winter were similar to the conditions that prevailed in the winter 2009/2010 and during spring 2010. We find that the 3 months following the Laki eruption in June 1783 barely had analogues in 2010. The cold winter of 1783/1784 yielded circulation analogues in 2009/2010. The reconstructed surface temperature over land bears significant correlations with local observations, although the amplitude of the reconstruction is weaker.
Global patterns of lightning properties derived by OTD and LIS
Authors: Beirle S. , Koshak W. , Blakeslee R. , Wagner T.
Published: April 2014

Abstract. The satellite instruments Optical Transient Detector (OTD) and Lightning Imaging Sensor (LIS) provide unique empirical data about the frequency of lightning flashes around the globe (OTD), and the tropics (LIS), which have been used before to compile a well received global climatology of flash rate densities. Here we present a statistical analysis of various additional lightning properties derived from OTD/LIS, i.e. the number of so-called "events" and "groups" per flash, as well as the mean flash duration, footprint and radiance. These normalized quantities, which can be associated with the flash "strength", show consistent spatial patterns; most strikingly, oceanic flashes show higher values than continental flashes for all properties. Over land, regions with high (Eastern US) and low (India) flash strength can be clearly identified. We discuss possible causes and implications of the observed regional differences. Although a direct quantitative interpretation of the investigated flash properties is difficult, the observed spatial patterns provide valuable information for the interpretation and application of climatological flash rates. Due to the systematic regional variations of physical flash characteristics, viewing conditions, and/or measurement sensitivities, parametrisations of lightning NOx based on total flash rate densities alone are probably affected by regional biases.
Scale invariant events and dry spells for medium-resolution local rain data
Authors: Deluca A. , Corral Á.
Published: April 2014

Abstract. We analyze distributions of rain-event sizes, rain-event durations, and dry-spell durations for data obtained from a network of 20 rain gauges scattered in a region of the northwestern Mediterranean coast. While power-law distributions model the dry-spell durations with a common exponent 1.50 ± 0.05, density analysis is inconclusive for event sizes and event durations, due to finite size effects. However, we present alternative evidence of the existence of scale invariance in these distributions by means of different data collapses of the distributions. These results demonstrate that scaling properties of rain events and dry spells can also be observed for medium-resolution rain data.
An ETKF approach for initial state and parameter estimation in ice sheet modelling
Authors: Bonan B. , Nodet M. , Ritz C. , Peyaud V.
Published: April 2014

Abstract. Estimating the contribution of Antarctica and Greenland to sea-level rise is a hot topic in glaciology. Good estimates rely on our ability to run a precisely calibrated ice sheet evolution model starting from a reliable initial state. Data assimilation aims to provide an answer to this problem by combining the model equations with observations. In this paper we aim to study a state-of-the-art ensemble Kalman filter (ETKF) to address this problem. This method is implemented and validated in the twin experiments framework for a shallow ice flowline model of ice dynamics. The results are very encouraging, as they show a good convergence of the ETKF (with localisation and inflation), even for small-sized ensembles.
Old Tensions, New Meanings, More Healing: An Analysis of the Season of Cambodia, Cambodian Rattan: The Sculptures of Sopheap Pich
Authors: Yaw Michelle
Published: April 2014

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Snapshots of the Female Body
Authors: Morrissey Julie
Published: April 2014

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The Angel at The Trestle
Authors: McLaughlin Liz
Published: April 2014

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Middling Culture: The Middlebrow, The Pulitzer, and Devotion to The Negative
Authors: Hood Kaeli
Published: April 2014

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Reviewer Acknowledgements for International Journal of Chemistry, Vol. 6, No. 2
Authors: John Albert
Published: April 2014

Reviewer acknowledgements for International Journal of Chemistry, Vol. 6, No. 2, 2014.
Establishing Standards for Mathematical Practice
Authors: Stephan Michelle L.
Published: April 2014

A grocery shopping problem can link the Common Core's standards with a new classroom culture.
Students with Learning Disabilities Tackle Multistep Problems
Authors: Hord Casey , Marita Samantha
Published: April 2014

Support math conversations and teach students to approach various problem-solving tasks by encouraging the use of tables.
Deciphering Multiplication Algorithms with the Area Model
Authors: Lee Ji-Eun
Published: April 2014

Prospective teachers explore Egyptian multiplication and Russian peasant multiplication to address the quantitative and qualitative relationships underlying these algorithms.
Math for Real: The Battle of Antietam
Authors: King Allesandra
Published: April 2014

This problem ties into real-life population estimates.
Differentiation of Mouse Induced Pluripotent Stem Cells Into Alveolar Epithelial Cells In Vitro for Use In Vivo
Authors: Zhou Qiliang , Ye Xulu , Sun Ruowen , Matsumoto Yoshifumi , Moriyama Masato , Asano Yoshiya , Ajioka Yoichi , Saijo Yasuo
Published: April 2014

Alveolar epithelial cells (AECs) differentiated from induced pluripotent stem cells (iPSCs) represent new opportunities in lung tissue engineering and cell therapy. In this study, we modified a two-step protocol for embryonic stem cells that resulted in a yield of ∼9% surfactant protein C (SPC)+ alveolar epithelial type II (AEC II) cells from mouse iPSCs in a 12-day period. The differentiated iPSCs showed morphological characteristics similar to those of AEC II cells. When differentiated iPSCs were seeded and cultured in a decellularized mouse lung scaffold, the cells reformed an alveolar structure and expressed SPC or T1α protein (markers of AEC II or AEC I cells, respectively). Finally, the differentiated iPSCs were instilled intratracheally into a bleomycin-induced mouse acute lung injury model. The transplanted cells integrated into the lung alveolar structure and expressed SPC and T1α. Significantly reduced lung inflammation and decreased collagen deposition were observed following differentiated iPSC transplantation. In conclusion, we report a simple and rapid protocol for in vitro differentiation of mouse iPSCs into AECs. Differentiated iPSCs show potential for regenerating three-dimensional alveolar lung structure and can be used to abrogate lung injury.
Paleoeskimo Occupation History of Foxe Basin, Arctic Canada: Implications for the Core Area Model and Dorset Origins
Authors: Savelle James M. , Dyke Arthur S.
Published: April 2014

This paper presents the first detailed record of Paleoeskimo occupation history of Foxe Basin, Nunavut, Arctic Canada, the traditional Paleoeskimo “core area.” Rather than continuous, stable occupations from approximately 4000–1000 B.P. traditionally assumed for the core area, the region has undergone a series of demographic oscillations, including several instances of abandonment of key areas, most notably Igloolik. The Foxe Basin demographic trends are reminiscent of Paleoeskimo “boom and bust” cycles recognized elsewhere, but show no consistent chronological pattern either within Foxe Basin or inter-regionally. Equally important, our results bear on the critical question of the Pre-Dorset to Dorset transition. Rather than having been a gradual in situ process centered within the core area, the demographic patterns, including the abrupt and widespread appearance of semi-subterranean dwellings during earliest Dorset, are consistent with newly arrived populations from outside of Foxe Basin. While there is no obvious “parent” culture to Dorset within the Eastern Arctic, it is suggested that a Western Arctic origin, specifically Norton Culture, invoking to some extent Jorgen Meldgaard’s “smell of the forest”, may have played a significant role.
Shifting Communities: Demographic Profiles of Early Village Population Growth and Decline in the Central American Bottom
Authors: Barrier Casey R. , Horsley Timothy J.
Published: April 2014

The growth and decline of large village communities is a topic of considerable interest for archaeologists studying the development of complex regional polities. In this article, demographic information is presented for the transitional Mississippian period Washausen mound center located in the American Bottom region of west-central Illinois. Population estimates are calculated based on data for residential architecture collected in 2011 during an extensive geophysical survey and excavations at the site. A magnetometer survey was conducted over 8 ha and produced a relatively complete site map revealing numerous household clusters organized around a central, earthen mound-and-plaza complex. Population estimates and site spatial information for Washausen are compared with similar data for earlier village communities located nearby, as well as other global village sequences, producing a demographic profile demonstrating a pattern of village growth and decline in the area after the onset of sedentism and agricultural intensification. Information from the region and elsewhere suggests that the development of larger communities through time resulted in part through frequent population movements as village segments fissioned and aggregated to form new communities. This research finding has the potential to inform models for the growth of much larger American Bottom centers such as Pulcher and Cahokia.
Origines et formes diverses du « destin manifeste » dans les Amériques : les Papineau et la United States Magazine and Democratic Review de Washington et New York
Authors: Harvey Louis-Georges , Lamonde Yvan
Published: April 2014

Axées sur l’avènement du Canada et la survivance de la collectivité canadienne-française, les traditions historiographiques canadienne et québécoise ne font que peu de place aux idées républicaines et à la pensée continentaliste. Pourtant, la conception d’un fédéralisme continental ancrée dans le destin démocratique des peuples du Nouveau Monde représentait un pendant important de l’idéologie républicaine de Louis-Joseph Papineau. En effet, la correspondance entre Papineau et son fils Amédée démontre que les deux hommes n’envisageaient rien de moins que l’émergence d’une nouvelle nationalité colombienne à l’échelle du continent nord-américain. Le providentialisme démocratique et républicain des Papineau s’inspirait d’un courant nationaliste, voire impérialiste, dont les origines remontaient à l’époque de la fondation des colonies anglo-américaines, mais qui s’actualisa au début des années 1840 dans la United States and Democratic Review de John L. O’Sullivan. La pensée continentaliste a aussi inspiré une vision bien différente de l’avenir du Canada français, des idéologues catholiques et plus tard ultramontains imaginant un destin glorieux pour leur petit peuple catholique qui devait par son caractère moral et pieux, sauver les masses protestantes de leur matérialisme effréné. Cette deuxième vision continentale, associée à Rameau de Saint-Père et à Étienne Parent, serait elle-même tributaire de réflexions françaises sur l’Amérique formulées au cours des années 1850. De part et d’autre, ces diverses destinées pour les Canadiens et pour l’Amérique s’inspiraient d’un discours messianique, soulignant dans chaque cas le caractère providentiel de leur vision de l’histoire.
Political Corruption as Deformities of Truth
Authors: Allard-Tremblay Yann
Published: April 2014

This paper presents a conception of corruption informed by epistemic democratic theory. I first explain the view of corruption as a disease of the political body. Following this view, we have to consider the type of actions that debase a political entity of its constitutive principal in order to assess corruption. Accordingly, we need to consider what the constitutive principle of democracy is. This is the task I undertake in the second section where I explicate democratic legitimacy. I present democracy as a procedure of social inquiry about what ought to be done that includes epistemic and practical considerations. In the third section, I argue that the problem of corruption for a procedural conception of democracy is that the epistemic value of the procedure is diminished by corrupted agents’ lack of concern for truth. Corruption, according to this view, consists in two deformities of truth: lying and bullshit. These deformities corrupt since they conceal private interests under the guise of a concern for truth. In the fourth section, I discuss the difficulties a procedural account may face in formulating solutions to the problem of corruption.
Transparency, Corruption, and Democratic Institutions1
Authors: Hubbs Graham
Published: April 2014

This essay examines some of the institutional arrangements that underlie corruption in democracy. It begins with a discussion of institutions as such, elaborating and extending some of John Searle’s remarks on the topic. It then turns to an examination of specifically democratic institutions; it draws here on Joshua Cohen’s recent Rousseau: A Free Community of Equals. One of the central concerns of Cohen’s Rousseau is how to arrange civic institutions so that they are able to perform their public functions without being easily abused by their members for individual gain. The view that Cohen sketches on behalf of Rousseau offers a clear framework for articulating institutional corruption in democracy. With this account of democratic institutions in place, the essay turns the discussion to the role of transparency in deterring institutional corruption. The basic thought here is perhaps unsurprising: to ensure that a democratic institution is serving its public function and not being manipulated for self-interested gain, its activities must be subject to public scrutiny, and so these activities must be transparent to the public. Saying this makes the role of transparency in a well-functioning democracy clear, but it does not settle how transparency is to be realized. The essay argues that transparency can be realized in a democracy only by an extra-governmental institution that has several of the familiar features of the press. If this is correct, it follows that in its design and in many, though not all, of its activities, WikiLeaks provides a contemporary example of such an institution.
Resveratrol modulates the inflammatory response via an estrogen receptor-signal integration network
Authors: Nwachukwu Jerome C , Srinivasan Sathish , Bruno Nelson E , Parent Alexander A , Hughes Travis S , Pollock Julie A , Gjyshi Olsi , Cavett Valerie , Nowak Jason , Garcia-Ordonez Ruben D , Houtman René , Griffin Patrick R , Kojetin Douglas J , Katzenellenbogen John A , Conkright Michael D , Nettles Kendall W
Published: April 2014

Resveratrol has beneficial effects on aging, inflammation and metabolism, which are thought to result from activation of the lysine deacetylase, sirtuin 1 (SIRT1), the cAMP pathway, or AMP-activated protein kinase. In this study, we report that resveratrol acts as a pathway-selective estrogen receptor-α (ERα) ligand to modulate the inflammatory response but not cell proliferation. A crystal structure of the ERα ligand-binding domain (LBD) as a complex with resveratrol revealed a unique perturbation of the coactivator-binding surface, consistent with an altered coregulator recruitment profile. Gene expression analyses revealed significant overlap of TNFα genes modulated by resveratrol and estradiol. Furthermore, the ability of resveratrol to suppress interleukin-6 transcription was shown to require ERα and several ERα coregulators, suggesting that ERα functions as a primary conduit for resveratrol activity.
Filament formation by metabolic enzymes is a specific adaptation to an advanced state of cellular starvation
Authors: Petrovska Ivana , Nüske Elisabeth , Munder Matthias C , Kulasegaran Gayathrie , Malinovska Liliana , Kroschwald Sonja , Richter Doris , Fahmy Karim , Gibson Kimberley , Verbavatz Jean-Marc , Alberti Simon
Published: April 2014

One of the key questions in biology is how the metabolism of a cell responds to changes in the environment. In budding yeast, starvation causes a drop in intracellular pH, but the functional role of this pH change is not well understood. Here, we show that the enzyme glutamine synthetase (Gln1) forms filaments at low pH and that filament formation leads to enzymatic inactivation. Filament formation by Gln1 is a highly cooperative process, strongly dependent on macromolecular crowding, and involves back-to-back stacking of cylindrical homo-decamers into filaments that associate laterally to form higher order fibrils. Other metabolic enzymes also assemble into filaments at low pH. Hence, we propose that filament formation is a general mechanism to inactivate and store key metabolic enzymes during a state of advanced cellular starvation. These findings have broad implications for understanding the interplay between nutritional stress, the metabolism and the physical organization of a cell.
Using VAAST to Identify Disease‐Associated Variants in Next‐Generation Sequencing Data
Authors: Kennedy Brett , Kronenberg Zev , Hu Hao , Moore Barry , Flygare Steven , Reese Martin G. , Jorde Lynn B. , Yandell Mark , Huff Chad
Published: April 2014

The VAAST pipeline is specifically designed to identify disease‐associated alleles in next‐generation sequencing data. In the protocols presented in this paper, we outline the best practices for variant prioritization using VAAST. Examples and test data are provided for case‐control, small pedigree, and large pedigree analyses. These protocols will teach users the fundamentals of VAAST, VAAST 2.0, and pVAAST analyses. Curr. Protoc. Hum. Genet. 81:6.14.1‐6.14.25. © 2014 by John Wiley & Sons, Inc.
Empirical orthogonal function analysis and modeling of the ionospheric peak height during the years 2002–2011
Authors: Lin Jian , Yue Xinan , Zeng Zhen , Lou Yidong , Shen Xuhui , Wu Yun , Schreiner William S. , Kuo Ying‐Hwa
Published: April 2014

The ionospheric peak electron density height (hm) is one of the most important ionospheric parameters characterizing high‐frequency radio wave propagation conditions. In this paper, a global hm model based on the empirical orthogonal function (EOF) analysis method is constructed by using Global Navigation Satellite Systems ionospheric radio occultation measurements from COSMIC and CHAMP as well as global ionosonde data during the years 2002–2011. The variability of hm can be well represented by the several EOF base functions Ek and the corresponding coefficients Pk. The rapid convergence of EOF decomposition makes it possible to use only the first four EOFs components, which express 99.133% of total variance in this study, to construct the empirical model. The variations of hm with respect to the magnetic latitude, local time, season, and solar cycle have been studied, and the EOF‐based hm model has been validated through comparisons with the International Reference Ionosphere (IRI) model and other observation. The evaluations indicate that the EOF and IRI model give better hmF2 at middle and high latitudes than those at low latitudes. Since the limited data were used in the EOF model during high solar activity years, its accuracy degrades to some extent. During nighttime of spring, summer, and winter in the auroral zone, the hm derived from the EOF model may range from 90 to 150 km because of the reduction of hm, which is due to particle precipitation, whereas the IRI model does not include this reduction. During the periods of low solar activity, the F2 peak heights (hmF2) from the EOF model are in good agreement with the observed data, while the IRI model tends to overestimate the hmF2 in the middle and high latitudes.
Large tectonic earthquakes induce sharp temporary decreases in seismic velocity in Volcán de Colima, Mexico
Authors: Lesage Philippe , Reyes‐Dávila Gabriel , Arámbula‐Mendoza Raúl
Published: April 2014

We used the ambient noise cross‐correlation and stretching methods to calculate variations in seismic velocities in the region of Volcán de Colima, Mexico. More than 15 years of continuous records were processed, producing long time series of velocity variations related to volcanic activity, meteorological effects, and earthquakes. Velocity variations associated with eruptive activity are tenuous, which probably reflects the open state of the volcano during the study period. Fifteen events among 26 regional tectonic earthquakes produced sharp, temporary decreases in seismic velocities, which then recovered progressively following a linear trend as a function of the logarithm of time. For the 15 events, the amplitude of the perturbation increased almost linearly with the logarithm of the amplitude of the seismic waves that shook the edifice. The most dramatic apparent velocity variation was a drop of up to 2.6% during the nearbyM7.4 Tecomán earthquake in 2003. In order to locate the perturbation in the horizontal plane we applied an inverse method based on the radiative transfer approximation. We also used an original approach based on the frequency dependence of velocity variations to estimate the depth of the perturbation. Our results show that the velocity variation was well localized in the shallow layers (< 800 m) of the volcano, with almost no variations occurring outside the edifice. We discuss several possible interpretations and conclude that the most plausible explanation for the velocity decreases is the nonlinear elastic behavior of the granular volcanic material and its mechanical softening induced by transient strains.
High‐resolution mapping of motor vehicle carbon dioxide emissions
Authors: McDonald Brian C. , McBride Zoe C. , Martin Elliot W. , Harley Robert A.
Published: April 2014

A fuel‐based inventory for vehicle emissions is presented for carbon dioxide (CO2) and mapped at various spatial resolutions (10 km, 4 km, 1 km, and 500 m) using fuel sales and traffic count data. The mapping is done separately for gasoline‐powered vehicles and heavy‐duty diesel trucks. Emission estimates from this study are compared with the Emissions Database for Global Atmospheric Research (EDGAR) and VULCAN. All three inventories agree at the national level within 5%. EDGAR uses road density as a surrogate to apportion vehicle emissions, which leads to 20–80% overestimates of on‐road CO2 emissions in the largest U.S. cities. High‐resolution emission maps are presented for Los Angeles, New York City, San Francisco‐San Jose, Houston, and Dallas‐Fort Worth. Sharp emission gradients that exist near major highways are not apparent when emissions are mapped at 10 km resolution. High CO2 emission fluxes over highways become apparent at grid resolutions of 1 km and finer. Temporal variations in vehicle emissions are characterized using extensive day‐ and time‐specific traffic count data and are described over diurnal, day of week, and seasonal time scales. Clear differences are observed when comparing light‐ and heavy‐duty vehicle traffic patterns and comparing urban and rural areas. Decadal emission trends were analyzed from 2000 to 2007 when traffic volumes were increasing and a more recent period (2007–2010) when traffic volumes declined due to recession. We found large nonuniform changes in on‐road CO2 emissions over a period of ~5 years, highlighting the importance of timely updates to motor vehicle emission inventories.
Dehydration in the tropical tropopause layer: A case study for model evaluation using aircraft observations
Authors: Ueyama Rei , Jensen Eric J. , Pfister Leonhard , Diskin Glenn S. , Bui T. P. , Dean‐Day Jonathan M.
Published: April 2014

The dynamical and microphysical processes that influence water vapor concentrations in the tropical tropopause layer (TTL) are investigated in simulations of ice clouds along backward trajectories of air parcels sampled during three flights of the Airborne Tropical Tropopause Experiment over the central to eastern tropical Pacific in boreal fall 2011. ERA‐Interim reanalysis temperatures interpolated onto the flight tracks have a negligible (−0.09 K) cold bias compared to aircraft measurements of tropical cold point temperature thus permitting case study simulations of TTL dehydration. When the effects of subgrid‐scale waves, cloud microphysical processes, and convection are considered, the simulated water vapor mixing ratios on the final day of 40 day backward trajectories exhibit a mean profile that is within 20–30% of the mean of the aircraft measurements collected during vertical profiling maneuvers between the 350 and 410 K potential temperature levels. Averaged over the three flights, temperature variability driven by subgrid‐scale waves dehydrated the 360–390 K layer by approximately −0.5 ppmv, whereas including homogeneous freezing of aqueous aerosols and subsequent sublimation and rehydration of ice crystals increased water vapor below the 380 K level by about +1 ppmv. The predominant impact of convection was to moisten the TTL, resulting in an average enhancement below the 370 K level by +1 to 5 ppmv. Accurate (to within 0.5–1 ppmv) predictions of TTL water vapor using trajectory models require proper representations of waves, in situ ice cloud formation, and convective influence, which together determine the saturation history of air parcels.
Long‐term changes in lower tropospheric baseline ozone concentrations: Comparing chemistry‐climate models and observations at northern midlatitudes
Authors: Parrish D. D. , Lamarque J.‐F. , Naik V. , Horowitz L. , Shindell D. T. , Staehelin J. , Derwent R. , Cooper O. R. , Tanimoto H. , Volz‐Thomas A. , Gilge S. , Scheel H.‐E. , Steinbacher M. , Fröhlich M.
Published: April 2014

Two recent papers have quantified long‐term ozone (O3) changes observed at northern midlatitude sites that are believed to represent baseline (here understood as representative of continental to hemispheric scales) conditions. Three chemistry‐climate models (NCAR CAM‐chem, GFDL‐CM3, and GISS‐E2‐R) have calculated retrospective tropospheric O3 concentrations as part of the Atmospheric Chemistry and Climate Model Intercomparison Project and Coupled Model Intercomparison Project Phase 5 model intercomparisons. We present an approach for quantitative comparisons of model results with measurements for seasonally averaged O3 concentrations. There is considerable qualitative agreement between the measurements and the models, but there are also substantial and consistent quantitative disagreements. Most notably, models (1) overestimate absolute O3 mixing ratios, on average by ~5 to 17 ppbv in the year 2000, (2) capture only ~50% of O3 changes observed over the past five to six decades, and little of observed seasonal differences, and (3) capture ~25 to 45% of the rate of change of the long‐term changes. These disagreements are significant enough to indicate that only limited confidence can be placed on estimates of present‐day radiative forcing of tropospheric O3 derived from modeled historic concentration changes and on predicted future O3 concentrations. Evidently our understanding of tropospheric O3, or the incorporation of chemistry and transport processes into current chemical climate models, is incomplete. Modeled O3 trends approximately parallel estimated trends in anthropogenic emissions of NOx, an important O3 precursor, while measured O3 changes increase more rapidly than these emission estimates.
Polar summer mesospheric extreme horizontal drift speeds during interplanetary corotating interaction regions (CIRs) and high‐speed solar wind streams: Coupling between the solar wind and the mesosphere
Authors: Lee Young‐Sook , Kirkwood Sheila , Kwak Young‐Sil , Kim Kyung‐Chan , Shepherd Gordon G.
Published: April 2014

We report the observation of echo extreme horizontal drift speed (EEHS, ≥ 300 m s−1) during polar mesospheric (80–90 km) summer echoes (PMSEs) by the VHF (52 MHz) radar at Esrange, Sweden, in years of 2006 and 2008. The EEHS occur in PMSEs as correlated with high‐speed solar wind streams (HSSs), observed at least once in 12–17% of all hours of observation for the two summers. The EEHS rate peaks occur either during high solar wind speed in the early part of the PMSE season or during the arrival of interplanetary corotating interaction regions (CIRs) followed by peaks in PMSE occurrence rate after 1–4 days, in the latter part of the 2006 summer. The cause of EEHS rate peaks is likely under the competition between the interval of the CIR and HSS passage over the magnetosphere. A candidate process in producing EEHS is suggested to be localized strong electric field, which is caused by solar wind energy transfer from the interaction of CIR and HSS with the magnetosphere in a sequential manner. We suggest that EEHS are created by strong electric field, estimated as > 10–30 V m−1 at 85 km altitude, exceeding the mesospheric breakdown threshold field.
Lunar dayside current in the terrestrial lobe: ARTEMIS observations
Authors: Zhou X.‐Z. , Angelopoulos V. , Poppe A. R. , Halekas J. S. , Khurana K. K. , Kivelson M. G. , Fatemi S. , Holmström M.
Published: April 2014

We report Acceleration, Reconnection, Turbulence and Electrodynamics of Moon's Interaction with the Sun (ARTEMIS) dual‐probe observations of two events in the terrestrial magnetotail lobe, both characterized by upward moving heavy ions of lunar origin at one of the probes that is magnetically connected with the dayside lunar surface. By treating magnetic measurements at the other probe as the unperturbed lobe fields, we obtain background‐subtracted magnetic perturbations (most significantly in Bz) when the first probe moved in the dawn‐dusk direction across flux tubes magnetically connected to the Moon. These magnetic perturbations indicate the presence of field‐aligned current above the lunar surface. By examining possible carriers of field‐aligned current, we find that lunar heavy ions and accompanying electrons both contribute considerably to the current. Observations of the field‐aligned current also suggest that the charging process at the dayside lunar surface and the associated lobe plasma environment, which have traditionally been viewed as a one‐dimensional current balance problem, are actually more complicated. These observations give the first insights into how heavy ions affect the lunar dayside environment in terms of multispecies plasma dynamics.
Ionosphere variability during the 2009 SSW: Influence of the lunar semidiurnal tide and mechanisms producing electron density variability
Authors: Pedatella N. M. , Liu H.‐L. , Sassi F. , Lei J. , Chau J. L. , Zhang X.
Published: April 2014

To investigate ionosphere variability during the 2009 sudden stratosphere warming (SSW), we present simulation results that combine the Whole Atmosphere Community Climate Model Extended version and the thermosphere‐ionosphere‐mesosphere electrodynamics general circulation model (TIME‐GCM). The simulations reveal notable enhancements in both the migrating semidiurnal solar (SW2) and lunar (M2) tides during the SSW. The SW2 and M2 amplitudes reach ∼50 m s−1 and ∼40 m s−1, respectively, in zonal wind at E region altitudes. The dramatic increase in the M2 at these altitudes influences the dynamo generation of electric fields, and the importance of the M2 on the ionosphere variability during the 2009 SSW is demonstrated by comparing simulations with and without the M2. TIME‐GCM simulations that incorporate the M2 are found to be in good agreement with Jicamarca Incoherent Scatter Radar vertical plasma drifts and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) observations of the maximum F region electron density. The agreement with observations is worse if the M2 is not included in the simulation, demonstrating that the lunar tide is an important contributor to the ionosphere variability during the 2009 SSW. We additionally investigate sources of the F region electron density variability during the SSW. The primary driver of the electron density variability is changes in electric fields. Changes in meridional neutral winds and thermosphere composition are found to also contribute to the electron density variability during the 2009 SSW. The electron density variability for the 2009 SSW is therefore not solely due to variability in electric fields as previously thought.
The origin of Jupiter's outer radiation belt
Authors: Woodfield E. E. , Horne R. B. , Glauert S. A. , Menietti J. D. , Shprits Y. Y.
Published: April 2014

The intense inner radiation belt at Jupiter (>50 MeV at 1.5 RJ) is generally accepted to be created by radial diffusion of electrons from further away from the planet. However, this requires a source with energies that exceed 1 MeV outside the orbit of the moon Io at 5.9 RJ, which has never been explained satisfactorily. Here we test the hypothesis that this source population could be formed from a very soft energy spectrum, by particle injection processes and resonant electron acceleration via whistler mode chorus waves. We use the British Antarctic Survey Radiation Belt Model to calculate the change in the electron flux between 6.5 and 15 RJ; these are the first simulations at Jupiter combining wave particle interactions and radial diffusion. The resulting electron flux at 100 keV and 1 MeV lies very close to the Galileo Interim Radiation Electron model spectrum after 1 and 10 days, respectively. The primary driver for the increase in the flux is cyclotron resonant acceleration by chorus waves. A peak in phase space density forms such that inside L≈9 radial diffusion transports electrons toward Jupiter, but outside L≈9 radial diffusion acts away from the planet. The results are insensitive to the softness of the initial energy spectrum but do depend on the value of the flux at the minimum energy boundary. We conclude by suggesting that the source population for the inner radiation belt at Jupiter could indeed be formed by wave‐particle interactions.
Increasing the credibility of regional climate simulations by introducing subgrid‐scale cloud‐radiation interactions
Authors: Herwehe Jerold A. , Alapaty Kiran , Spero Tanya L. , Nolte Christopher G.
Published: April 2014

The radiation schemes in the Weather Research and Forecasting (WRF) model have previously not accounted for the presence of subgrid‐scale cumulus clouds, thereby resulting in unattenuated shortwave radiation, which can lead to overly energetic convection and overpredicted surface precipitation. This deficiency can become problematic when applying WRF as a regional climate model (RCM). Therefore, modifications were made to the WRF model to allow the Kain–Fritsch (KF) convective parameterization to provide subgrid‐scale cloud fraction and condensate feedback to the rapid radiative transfer model–global (RRTMG) shortwave and longwave radiation schemes. The effects of these changes are analyzed via 3 year simulations using the standard and modified versions of WRF, comparing the modeled results with the North American Regional Reanalysis (NARR) and Climate Forecast System Reanalysis data, as well as with available data from the Surface Radiation Network and Clouds and Earth's Radiant Energy System. During the summer period, including subgrid cloudiness estimated by KF in the RRTMG reduces the surface shortwave radiation, leading to less buoyant energy, which is reflected in a smaller diabatic convective available potential energy, thereby alleviating the overly energetic convection. Overall, these changes have reduced the overprediction of monthly, regionally averaged precipitation during summer for this RCM application, e.g., by as much as 49 mm for the southeastern U.S., to within 0.7% of the NARR value of 221 mm. These code modifications have been incorporated as an option available in the latest version of WRF (v3.6).
Phase Change Heat Insulation Based on Wax‐Clay Nanotube Composites
Authors: Zhao Yafei , Thapa Suvhashis , Weiss Leland , Lvov Yuri
Published: April 2014

Wax can be used as a phase change material in solar energy storage but has low thermal conductivity and cannot sustain shape at higher temperature (above 55 °C). Introducing 50% halloysite clay nanotubes into wax yields a stable and homogenous phase change composite with thermal conductivity of 0.36 Wm–1 K–1 and no leaking until 70 °C. Graphite and carbon nanotubes can further increase the conductivity and shape stabilized temperature as high as 1.4 Wm−1 K−1 and 91°C. Vectorial thermal energy transfer for double layers of different composition was demonstrated: heat flux difference in the opposite directions differed by 25%. The new wax‐nanoclay composite is a promising heat storage material due to good heat capacity, high thermal conductivity and ability to preserve its shape during wax melting.
Nutrition and foraging strategies of the black howler monkey (Alouatta pigra) in Palenque National Park, Mexico
Authors: Amato Katherine R. , Garber Paul A.
Published: April 2014

Food resources consumed by primates vary markedly in nutritional content. As a result, foragers must develop a feeding strategy to select resources that balance energy and macronutrient intake and reduce the consumption of fiber and toxins. In this study, we collected data on dietary patterns, rates of food consumption, and weight of food items consumed and combined them with published values of the nutritional content of Neotropical foods to estimate energy and nutrient intake during a 10‐month period in two groups (N = 16 individuals) of black howler monkeys (Alouatta pigra) inhabiting Palenque National Park, Mexico. Although howler monkeys are generally assumed to exploit a leaf‐dominated diet and be energy‐limited, our results indicated that black howlers met their estimated energy requirements, consuming an average of 0.58 MJ of overall energy per metabolic body mass per day. The howlers also surpassed protein requirements by consuming an average of 8.2 g of protein per metabolic body mass per day. The amount of time they spent resting was not correlated with the amount of leaves or fruit in the diet or with overall energy intake. Therefore, despite consuming a leaf‐heavy diet during some months of the year, black howlers do not appear to be energy‐limited. Additionally, the howlers maintained a relatively consistent level of average daily protein energy intake regardless of diet composition, while non‐protein energy intake varied in response to the amount of ripe fruits consumed. Although our use of published nutritional data introduces error, these findings suggest that black howler feeding ecology is more similar to other fruit‐eating atelines than previously suspected, and several common assumptions regarding howler behavior and feeding ecology need to be reexamined. Am. J. Primatol. 76:774–787, 2014. © 2014 Wiley Periodicals, Inc.
Zentren der Methanaktivierung auf Oberflächen von Lithium‐dotiertem MgO
Authors: Kwapien Karolina , Paier Joachim , Sauer Joachim , Geske Michael , Zavyalova Ulyana , Horn Raimund , Schwach Pierre , Trunschke Annette , Schlögl Robert
Published: April 2014

Die mittels Dichtefunktionaltheorie berechneten Energiebarrieren für die H‐Abstraktion durch Sauerstoffradikale in Li‐dotiertem MgO sind viel kleiner (12±6 kJ mol−1) als die Barrieren, die man bei unterschiedlichen Methanaktivierungsexperimenten findet (80–160 kJ mol−1). Das nährt weitere Zweifel an Lunsfords Hypothese, dass Li+O.−‐Paare die aktiven Zentren sind. Temperaturprogrammierte oxidative Kupplungsreaktionen von Methan (OCM) zeigen, dass bei reinem und Li‐dotiertem MgO die gleichen Zentren für die Reaktion verantwortlich sind. MgO‐Katalysatoren, die durch Sol‐Gel‐Synthese hergestellt wurden, zeigen große Unterschiede zwischen anfänglicher Aktivität und der Aktivität im stationären Zustand. Transmissionselektronenmikroskopie zeigt, dass damit substanzielle morphologische Veränderungen und Restrukturierungen der Oberfläche einhergehen. Berechnungen an (MgO)9‐Clustermodellen ergeben, dass CH4 heterolytisch an Mg2+O2−‐Paaren chemisorbiert wird, die sich an Stufen oder Ecken befinden. Die homolytische Freisetzung von Methylradikalen erfordert jedoch die Anwesenheit von O2 auf der Oberfläche.
Inverse Peptide Synthesis via Activated α‐Aminoesters
Authors: Suppo Jean‐Simon , Subra Gilles , Bergès Matthieu , Marcia de Figueiredo Renata , Campagne Jean‐Marc
Published: April 2014

A mild, practical, and simple procedure for peptide‐bond formation is reported. Instead of activation of the carboxylic acid functionality, the reaction involves an unprecedented use of activated α‐aminoesters. The method provides a straightforward entry to dipeptides and was effective when a sensitive cysteine residue was used, as no epimerization was detected in this case. The applicability of this method to iterative peptide synthesis was illustrated by the synthesis of a model tetrapeptide in the challenging reverse N→C direction.