bluuebunny/crossref_metadata_2025 huggingface dataset:
Camera Sensor Arrangement for Crop/Weed Detection Accuracy in Agronomic Images
Authors: Romeo Juan , Guerrero José , Montalvo Martín , Emmi Luis , Guijarro María , Gonzalez-de-Santos Pablo , Pajares Gonzalo
Published: April 2013

In Precision Agriculture, images coming from camera-based sensors are commonly used for weed identification and crop line detection, either to apply specific treatments or for vehicle guidance purposes. Accuracy of identification and detection is an important issue to be addressed in image processing. There are two main types of parameters affecting the accuracy of the images, namely: (a) extrinsic, related to the sensor’s positioning in the tractor; (b) intrinsic, related to the sensor specifications, such as CCD resolution, focal length or iris aperture, among others. Moreover, in agricultural applications, the uncontrolled illumination, existing in outdoor environments, is also an important factor affecting the image accuracy. This paper is exclusively focused on two main issues, always with the goal to achieve the highest image accuracy in Precision Agriculture applications, making the following two main contributions: (a) camera sensor arrangement, to adjust extrinsic parameters and (b) design of strategies for controlling the adverse illumination effects.
Numerical Analysis of Piezoelectric Active Repair in the Presence of Frictional Contact Conditions
Authors: Alaimo Andrea , Milazzo Alberto , Orlando Calogero , Messineo Antonio
Published: April 2013

The increasing development of smart materials, such as piezoelectric and shape memory alloys, has opened new opportunities for improving repair techniques. Particularly, active repairs, based on the converse piezoelectric effect, can increase the life of a structure by reducing the crack opening. A deep characterization of the electromechanical behavior of delaminated composite structures, actively repaired by piezoelectric patches, can be achieved by considering the adhesive layer between the host structure and the repair and by taking into account the frictional contact between the crack surfaces. In this paper, Boundary Element (BE) analyses performed on delaminated composite structures repaired by active piezoelectric patches are presented. A two-dimensional boundary integral formulation for piezoelectric solids based on the multi-domain technique to model the composite host damaged structures and the bonded piezoelectric patches is employed. An interface spring model is also implemented to take into account the finite stiffness of the bonding layers and to model the frictional contact between the delamination surfaces, by means of an iterative procedure. The effect of the adhesive between the plies of piezoelectric bimorph devices on the electromechanical response is first pointed out for both sensing and actuating behavior. Then, the effect of the frictional contact condition on the fracture mechanics behavior of actively repaired delaminated composite structures is investigated.
A High Precision Feature Based on LBP and Gabor Theory for Face Recognition
Authors: Xia Wei , Yin Shouyi , Ouyang Peng
Published: April 2013

How to describe an image accurately with the most useful information but at the same time the least useless information is a basic problem in the recognition field. In this paper, a novel and high precision feature called BG2D2LRP is proposed, accompanied with a corresponding face recognition system. The feature contains both static texture differences and dynamic contour trends. It is based on Gabor and LBP theory, operated by various kinds of transformations such as block, second derivative, direct orientation, layer and finally fusion in a particular way. Seven well-known face databases such as FRGC, AR, FERET and so on are used to evaluate the veracity and robustness of the proposed feature. A maximum improvement of 29.41% is achieved comparing with other methods. Besides, the ROC curve provides a satisfactory figure. Those experimental results strongly demonstrate the feasibility and superiority of the new feature and method.
Effect of Powdered Activated Carbon to Reduce Fouling in Membrane Bioreactors: A Sustainable Solution. Case Study
Authors: Torretta Vincenzo , Urbini Giordano , Raboni Massimo , Copelli Sabrina , Viotti Paolo , Luciano Antonella , Mancini Giuseppe
Published: April 2013

Membrane Bio Reactors (MBRs) are mainly used for industrial wastewaters applications where their costs can be more easily afforded. High costs are basically due to energy consumption and membrane cleaning or replacement. Membrane fouling is responsible for reducing treated water production and increasing maintenance as well as operation costs. According to previous researches, the addition of Powdered Activated Carbon (PAC) in high dosages could reduce membrane fouling; but such concentrations are economically unsustainable for operative conditions. A MBR pilot plant, fed by mixed liquor of a full-scale activated sludge process from a municipal wastewater treatment plant, was operated dosing low PAC concentrations (0, 2, 5, 10 and 20 mg·L−1, respectively). Experiments were also carried out at two different temperatures corresponding to summer and winter conditions. Results indicated that PAC addition was effective at the low dosages (2 and 5 mg·L−1) by reducing the permeate flux loss (from 16 up to 27%, respectively) while higher PAC concentrations turns out in a useless cost increase.
Action Research’s Potential to Foster Institutional Change for Urban Water Management
Authors: Zikos Dimitrios , Thiel Andreas
Published: April 2013

The paper discusses the potential of action research to meet the challenges entailed in institutional design for urban water management. Our overall aim is to briefly present action research and discuss its methodological merits with regard to the challenges posed by the different conceptual bases for extrapolating the effects of institutional design on institutional change. Thus, our aim is to explore how Action Research meets the challenge of scoping the field in an open fashion for determining the appropriate mechanisms of institutional change and supporting the emerging of new water institutions. To accomplish this aim, we select the Water Framework Directive (WFD) as an illustrative driving force requiring changes in water management practices and implying the need for the emergence of new institutions. We employ a case of urban water management in the Volos Metropolitan Area, part of the Thessaly region in Greece, where a Pilot River Basin Plan was implemented. By applying action research and being involved in a long process of interaction between stakeholders, we examine the emergence of new institutions dealing with urban water management under the general principles of the major driving force for change: the WFD.
Safety of Rituximab in Combination with Other Biologic Disease-modifying Antirheumatic Drugs in Rheumatoid Arthritis: An Open-label Study
Authors: Rigby William F.C. , Mease Philip J. , Olech Ewa , Ashby Mark , Tole Swati
Published: April 2013

Objective.

To characterize the safety of rituximab (RTX) in combination with biologic disease-modifying antirheumatic drugs (DMARD) in patients with rheumatoid arthritis (RA).

Methods.

We did an open-label study of the safety and efficacy of RTX in adult patients with active RA and an inadequate response to ≥ 1 biologic for ≥ 12 weeks (stable dose ≥ 4 weeks). RTX (2 × 500 mg) was added to patients’ current biologic and nonbiologic DMARD treatment. After 24 weeks, patients with 28-joint Disease Activity Score ≥ 2.6 were eligible for RTX retreatment. The primary endpoint was the proportion of patients developing a serious adverse event (SAE) within 24 weeks of initiating RTX.

Results.

Patients (n = 176) received RTX with 18 different biologic/DMARD combinations. Adalimumab alone (n = 46; 26.1%) or etanercept alone (n = 37; 21.0%) plus RTX were the most common combinations. Overall, 90.9% and 76.1% of patients completed 24 and 48 weeks, respectively; 147 patients (83.5%) received a second course of RTX. Over 24 weeks, 9.1% of patients reported SAE (24.3 events/100 patient-yrs, 95% CI 15.5–38.1). The SAE rate was similar over 48 weeks (22.4 events/100 patient-yrs, 95% CI 15.9–31.5). Four serious infections were reported over 48 weeks (2.7 events/100 patient-yrs, 95% CI 1.0–7.2). No SAE occurred within 24 h of any RTX infusion. Efficacy responses improved numerically at Week 48 compared with Week 24.

Conclusion.

The overall safety profile of RTX in combination with 1 other biologic was consistent with that previously reported for RTX plus methotrexate or other nonbiologic DMARD. (Clinicaltrials.govNCT00443651)
El significado histórico de las aportaciones de Marañón en el campo de la endocrinología internacional
Authors: Aguirre Marco Carla P.
Published: April 2013

Una aproximación a la temprana difusión internacional de la obra endocrinológica de Marañón permite situar su protagonismo en el nacimiento de la especialidad médica en España en el marco de la endocrinología internacional, que cristalizaba en la medicina clínica europea de la misma generación de Marañón, la de 1914. Lo hacía sirviendo a una corriente renovadora que centraba de nuevo la mentalidad médica en la persona del paciente, por lo que no se concibió inicialmente la posibilidad de su escisión como especialidad médica.
¿Qué es una emoción?
Authors: Mora Teruel Francisco
Published: April 2013

El Dr. Gregorio Marañón no escribió mucho sobre la emoción. Pero sí es cierto que consideró que se trataba de “uno de los problemas más interesantes de la vida humana”. En este artículo se describen los procesos cerebrales básicos de la emoción que nos alertan y motivan hacia la realización de conductas en cuyo significado último se encuentra la supervivencia del individuo y de la especie. Se describe el procesamiento emocional de la información sensorial. Se señala que todo proceso de aprendizaje y memoria consciente siempre viene coloreado emocionalmente. Y se destaca que el profesor Marañón posiblemente mostraría asombro ante una de las principales conclusiones de este artículo en las que se indica que no hay pensamiento sin una emoción previa que lo alimente. Que no hay razón sin emoción.
Marañón, historiador
Authors: López Vega Antonio
Published: April 2013

La obra histórica de Marañón distingue dos etapas claramente diferenciadas, antes y después de su exilio en París con motivo de la Guerra Civil española (1936-1942). Si antes de la guerra su obra estuvo caracterizada por las conocidas como psicobiografías, estudios del alma humana tratando de comprender los resortes del comportamiento de determinados personajes históricos, después, sus trabajos históricos estuvieron marcados por la experiencia de su propio exilio y, en lo metodológico, recogían los nuevos aires que renovaban la historiografía de la mano de la conocida como Escuela de los Annales que había aparecido en Francia al finalizar la década de 1920. Este artículo recoge un balance de la obra histórica de Marañón en su conjunto.
Jueces, represión y justicia transicional en España, Chile y Argentina
Authors: Aguilar Paloma
Published: April 2013

¿Por qué algunas democracias han avanzado tanto en el esclarecimiento y la persecución judicial de las violaciones de derechos humanos cometidas por las dictaduras precedentes, mientras que otras mantienen vigentes leyes de amnistía que impiden —o, al menos, dificultan— la aprobación de dichas medidas? Nos proponemos demostrar que, durante los procesos de democratización, cuanto más “legal” haya sido la represión dictatorial, y mayor sea la implicación de los jueces en ella, mayor resistencia existirá a la aplicación de políticas de justicia transicional. Nos proponemos comparar el caso español con el chileno y el argentino. En los tres países hubo dictaduras de corte conservador, la violación de derechos humanos fue sistemática y, cuando se democratizaron, tuvieron que reflexionar sobre qué hacer con este pasado de violencia política. Una vez que la democracia se ha consolidado, factores adicionales contribuirán a explicar la presencia o ausencia de rendición de cuentas en el ámbito judicial.
Bienestar subjetivo, renta y bienes relacionales. Los determinantes de la felicidad en España
Authors: Iglesias Vázquez Emma , Pena López José Atilano , Sánchez Santos José Manuel
Published: April 2013

En el presente trabajo se analizan los determinantes de la felicidad, entendida esta como satisfacción subjetiva revelada. El principal objetivo tiene un doble componente: por un lado, se trata de contrastar la paradoja de Easterlin para la sociedad española (ausencia de un vínculo directo entre el incremento de la renta per capita y la evolución del bienestar subjetivo revelado a nivel agregado) y, por otro, evaluar el papel que desempeñan los bienes relacionales como determinantes de la felicidad. El marco analítico adoptado se encuadra dentro de la denominada happiness economics y la evidencia empírica se deriva de la estimación de una función microeconométrica de la felicidad aplicando un modelo Logit tanto en cortes temporales como en datos de panel. Los resultados obtenidos permiten concluir que en España el ingreso desempeña un papel secundario y subjetivo, mientras que se revelan como importantes las variables asociadas directa o indirectamente a los bienes relacionales.
A Constructive Approach to the Evolution of the Planning Ability
Authors: Minoya Kenichi , Unemi Tatsuo , Suzuki Reiji , Arita Takaya
Published: April 2013

Human beings have behavioral flexibility based on a general faculty of planning for future events. This paper describes the first stage of a study on the evolution of planning abilities. A blocks world problem is used as a task to be solved by the agents, and encode an inherent planning parameter into the genome. The result of computer simulation shows a general tendency that planning ability emerges when the problem is difficult to solve. When taking social relationships, especially in the collective situation, into account, planning ability is difficult to evolve in the case that the problem is complex because there is a conflict between personal and collective interests. Also, the simulation results indicate that sharing information facilitates evolution of the planning ability although the free rider problem tends to be more serious than the situation where agents do not share information. It implies that there is a strong connection between evolution of the planning ability and symbolic communication.
Using Web Surveys for Psychology Experiments
Authors: Peden Blaine F. , Tiry Andrew M.
Published: April 2013

This chapter provides readers with a practical guide about how to use commercial Web survey systems for Internet research. The authors frame their approach in terms of stages in the online research process: (1) ideation, (2) implementation, (3) distribution, (4) collection, (5) analysis, (6) dissemination, and (7) retention. Although they focus on implementing psychology experiments, many of their guidelines also apply to survey research. The authors draw parallels between applied (i.e., therapeutic intervention) and basic online research. One conclusion is that there are many methodological, ethical, and technological issues associated with each stage in the online research process. A second conclusion is that their approach benefits both researchers and participants. Future online researchers should modify the analysis and guidelines in light of the contemporary literature.
Origin of a carbonate-rich breccia at Lake Minogami, Shawinigan area, Grenville Province, Quebec
Authors: Nadeau L , Nadeau S , Brouillette P
Published: April 2013

The Lake Minogami carbonate breccia (LMCB) exhibits field characteristics similar to those of a carbonatite diatreme, but a geochemical signature reflecting derivation from nearby marbles. The rocks display a very fine grained calcite matrix containing
mechanically abraded rounded rock fragments. The breccia shows mineralogy and geochemistry distinct from carbonatites, namely a high SiO2 content (÷30%), low abundances of compatible and incompatible trace elements and limited REE fractionation. In addition, breccia samples show REE normalized
patterns parallel to those of nearby tectonic marble and comparable 13C and 18O values. These features provide strong evidence for the derivation of the Lake Minogami carbonate breccia matrix by remobilization of a marble protolith. The presence of microfractures filled by calcite in both rock
fragments and xenocrysts, rare subgrains and neoblasts around xenocrysts, as well as bent twins and kinks in matrix calcite provide additional support for a tectonic origin.
Relationship between crustal deformation and magmatism in rift zones: modelling approach and applications to the eastern Canadian margin
Authors: Williamson M -C , Courtney R C , Keen C E , Dehler S
A
Published: April 2013

A model of lithospheric stretching and associated mantle melting is described which predicts the geographic distribution, volume, and trace element composition of basaltic magmas generated in rifts. Melt volumes are computed from the post-rift and syn-rift
subsidences that account for the thickness of the sedimentary sequence. The concentrations of rare-earth elements (REE) are calculated by applying a sequential melting model to values of the melt fraction vs. depth. The predicted melt volumes and REE concentrations are sensitive to variations in the
basal mantle temperature, magnitude of subcrustal stretching, and rifting history. Given moderately high temperatures and large degrees of stretching in the upper mantle, the geochemical model is capable of generating alkaline melts, and predicts the transition from alkaline to tholeiitic magmatism
observed in many continental rifts. The model results are currently being constrained with data from the Labrador margin.
Development of an Automated, Real Time Surveillance Tool for Predicting Readmissions at a Community Hospital
Authors: Gildersleeve R. , Cooper P.
Published: April 2013

Background: The Centers for Medicare and Medicaid Services’ Readmissions Reduction Program adjusts payments to hospitals based on 30-day readmission rates for patients with acute myocardial infarction, heart failure, and pneumonia. This holds hospitals accountable for a complex phenomenon about which there is little evidence regarding effective interventions. Further study may benefit from a method for efficiently and inexpensively identifying patients at risk of readmission. Several models have been developed to assess this risk, many of which may not translate to a U.S. community hospital setting.

Objective: To develop a real-time, automated tool to stratify risk of 30-day readmission at a semi-rural community hospital.

Methods: A derivation cohort was created by extracting demographic and clinical variables from the data repository for adult discharges from calendar year 2010. Multivariate logistic regression identified variables that were significantly associated with 30-day hospital readmission. Those variables were incorporated into a formula to produce a Risk of Readmission Score (RRS). A validation cohort from 2011 assessed the predictive value of the RRS. A SQL stored procedure was created to calculate the RRS for any patient and publish its value, along with an estimate of readmission risk and other factors, to a secure intranet site.

Results: Eleven variables were significantly associated with readmission in the multivariate analysis of each cohort. The RRS had an area under the receiver operating characteristic curve (c-statistic) of 0.74 (95% CI 0.73-0.75) in the derivation cohort and 0.70 (95% CI 0.69-0.71) in the validation cohort.

Conclusion: Clinical and administrative data available in a typical community hospital database can be used to create a validated, predictive scoring system that automatically assigns a probability of 30-day readmission to hospitalized patients. This does not require manual data extraction or manipulation and uses commonly available systems. Additional study is needed to refine and confirm the findings.

Citation: Gildersleeve R, Cooper P. Development of an automated, real time surveillance tool for predicting readmissions at a community hospital. Appl Clin Inf 2013; 4: 153–169

http://dx.doi.org/10.4338/ACI-2012-12-RA-0058
The influence of snow grain size and impurities on the vertical profiles of actinic flux and associated NOx emissions on the Antarctic and Greenland ice sheets
Authors: Zatko M. C. , Grenfell T. C. , Alexander B. , Doherty S. J. , Thomas J. L. , Yang X.
Published: April 2013

Abstract. We use observations of the absorption properties of black carbon and non-black carbon impurities in near-surface snow collected near the research stations at South Pole and Dome C, Antarctica, and Summit, Greenland, combined with a snowpack actinic flux parameterization to estimate the vertical profile and e-folding depth of ultraviolet/near-visible (UV/near-vis) actinic flux in the snowpack at each location. We have developed a simple and broadly applicable parameterization to calculate depth and wavelength dependent snowpack actinic flux that can be easily integrated into large-scale (e.g., 3-D) models of the atmosphere. The calculated e-folding depths of actinic flux at 305 nm, the peak wavelength of nitrate photolysis in the snowpack, are 8–12 cm near the stations and 15–31 cm away (>11 km) from the stations. We find that the e-folding depth is strongly dependent on impurity content and wavelength in the UV/near-vis region, which explains the relatively shallow e-folding depths near stations where local activities lead to higher snow impurity levels. We calculate the lifetime of NOx in the snowpack interstitial air produced by photolysis of snowpack nitrate against wind pumping (τwind pumping) from the snowpack, and compare this to the calculated lifetime of NOx against chemical conversion to HNO3 (τchemical) to determine whether the NOx produced at a given depth can escape from the snowpack to the overlying atmosphere. Comparison of τwind pumping and τchemical suggests efficient escape of photoproduced NOx in the snowpack to the overlying atmosphere throughout most of the photochemically active zone. Calculated vertical actinic flux profiles and observed snowpack nitrate concentrations are used to estimate the potential flux of NOx from the snowpack. Calculated NOx fluxes of 4.4 × 108–3.8 × 109 molecules cm−2 s−1 in remote polar locations and 3.2–8.2 × 108 molecules cm−2 s−1 near polar stations for January at Dome C and South Pole and June at Summit suggest that NOx flux measurements near stations may be underestimating the amount of NOx emitted from the clean polar snowpack.
CH4 and CO distributions over tropical fires during October 2006 as observed by the Aura TES satellite instrument and modeled by GEOS-Chem
Authors: Worden J. , Wecht K. , Frankenberg C. , Alvarado M. , Bowman K. , Kort E. , Kulawik S. , Lee M. , Payne V. , Worden H.
Published: April 2013

Abstract. Tropical fires represent a highly uncertain source of atmospheric methane (CH4) because of the variability of fire emissions and the dependency of the fire CH4 emission factors (g kg−1 dry matter burned) on fuel type and combustion phase. In this paper we use new observations of CH4 and CO in the free troposphere from the Aura Tropospheric Emission Sounder (TES) satellite instrument to place constraints on the role of tropical fire emissions versus microbial production (e.g. in wetlands and livestock) during the (October) 2006 El Niño, a time of significant fire emissions from Indonesia. We first compare the global CH4 distributions from TES using the GEOS-Chem model. We find a mean bias between the observations and model of 26.3 ppb CH4 that is independent of latitude between 50° S and 80° N, consistent with previous validation studies of TES CH4 retrievals using aircraft measurements. The slope of the distribution of CH4 versus CO as observed by TES and modeled by GEOS-Chem is consistent (within the TES observation error) for air parcels over the Indonesian peat fires, South America, and Africa. The CH4 and CO distributions are correlated between R = 0.42 and R = 0.46, with these correlations primarily limited by the TES random error. Over Indonesia, the observed slope of 0.13 (ppb ppb−1) ±0.01, as compared to a modeled slope of 0.153 (ppb ppb−1) ±0.005 and an emission ratio used within the GEOS-Chem model of approximately 0.11 (ppb ppb−1), indicates that most of the observed methane enhancement originated from the fire. Slopes of 0.47 (ppb ppb−1) ±0.04 and 0.44 (ppb ppb−1) ±0.03 over South America and Africa show that the methane in the observed air parcels primarily came from microbial-generated emissions. Sensitivity studies using GEOS-Chem show that part of the observed correlation for the Indonesian observations and most of the observed correlations over South America and Africa are a result of transport and mixing of the fire and nearby microbial-generated emissions into the observed air parcels. Differences between observed and modeled CH4 distributions over South America and southern Africa indicate that the magnitude of the methane emissions for this time period are inconsistent with observations even if the relative distribution of fire versus biotic emissions are consistent. This study shows the potential for estimation of CH4 emissions over tropical regions using joint satellite observations of CH4 and CO.
Aerosol and precipitation chemistry in the southwestern United States: spatiotemporal trends and interrelationships
Authors: Sorooshian A. , Shingler T. , Harpold A. , Feagles C. W. , Meixner T. , Brooks P. D.
Published: April 2013

Abstract. This study characterizes the spatial and temporal patterns of aerosol and precipitation composition at six sites across the United States Southwest between 1995 and 2010. Precipitation accumulation occurs mostly during the wintertime (December–February) and during the monsoon season (July–September). Rain and snow pH levels are usually between 5–6, with crustal-derived species playing a major role in acid neutralization. These species (Ca2+, Mg2+, K+,Na+) exhibit their highest concentrations between March and June in both PM2.5 and precipitation due mostly to dust. Crustal-derived species concentrations in precipitation exhibit positive relationships with SO42−, NO3−, and Cl−, suggesting that acidic gases likely react with and partition to either crustal particles or hydrometeors enriched with crustal constituents. Concentrations of particulate SO42− show a statistically significant correlation with rain SO42− unlike snow SO42−, which may be related to some combination of the vertical distribution of SO42− (and precursors) and the varying degree to which SO42−-enriched particles act as cloud condensation nuclei versus ice nuclei in the region. The coarse : fine aerosol mass ratio was correlated with crustal species concentrations in snow unlike rain, suggestive of a preferential role of coarse particles (mainly dust) as ice nuclei in the region. Precipitation NO3− : SO42− ratios exhibit the following features with potential explanations discussed: (i) they are higher in precipitation as compared to PM2.5; (ii) they exhibit the opposite annual cycle compared to particulate NO3− : SO42− ratios; and (iii) they are higher in snow relative to rain during the wintertime. Long-term trend analysis for the monsoon season shows that the NO3− : SO42− ratio in rain decreased at the majority of sites due mostly to air pollution regulations of SO42− precursors.
Heterogeneous formation of polar stratospheric clouds – Part 2: Nucleation of ice on synoptic scales
Authors: Engel I. , Luo B. P. , Pitts M. C. , Poole L. R. , Hoyle C. R. , Grooß J.-U. , Dörnbrack A. , Peter T.
Published: April 2013

Abstract. This paper provides unprecedented evidence for the importance of heterogeneous nucleation, likely on solid particles of meteoritic origin, and of small-scale temperature fluctuations, for the formation of ice particles in the Arctic stratosphere. During January 2010, ice PSCs (Polar Stratospheric Clouds) were shown by CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) to have occurred on a synoptic scale (~ 1000 km dimension). CALIPSO observations also showed widespread PSCs containing nitric acid trihydrate (NAT) particles in December 2009, prior to the occurrence of synoptic-scale regions of ice PSCs during mid-January 2010. We demonstrate by means of detailed microphysical modeling along air parcel trajectories that the formation of these PSCs is not readily reconciled with expectations from the conventional understanding of PSC nucleation mechanisms. The measurements are at odds with the previous laboratory-based understanding of PSC formation, which deemed direct heterogeneous nucleation of NAT and ice on preexisting solid particles unlikely. While a companion paper (Part 1) addresses the heterogeneous nucleation of NAT during December 2009, before the existence of ice PSCs, this paper shows that also the large-scale occurrence of stratospheric ice in January 2010 cannot be explained merely by homogeneous ice nucleation but requires the heterogeneous nucleation of ice, e.g. on meteoritic dust or preexisting NAT particles. The required efficiency of the ice nuclei is surprisingly high, namely comparable to that of known tropospheric ice nuclei such as mineral dust particles. To gain model agreement with the ice number densities inferred from observations, the presence of small-scale temperature fluctuations, with wavelengths unresolved by the numerical weather prediction models, is required. With the derived rate parameterization for heterogeneous ice nucleation we are able to explain and reproduce CALIPSO observations throughout the entire Arctic winter 2009/2010.
Uptake of HO2 radicals on Arizona test dust surface
Authors: Bedjanian Y. , Romanias M. N. , El Zein A.
Published: April 2013

Abstract. The interaction of HO2 radicals with solid films of Arizona Test Dust (ATD) was studied using a low pressure flow reactor (1–9 Torr) combined with a modulated molecular beam mass spectrometer for monitoring of the gaseous species involved. The reactive uptake coefficient of HO2 was measured from the kinetics of HO2 consumption on Pyrex rods coated with ATD as a function of HO2 concentration ((0.35–3.30) × 1012 molecule cm−3), relative humidity (RH = 0.02–94%), temperature (T = 275–320 K) and UV irradiance intensity (JNO2 = 0–0.012 s−1). The initial uptake coefficient was found to be independent of concentration of HO2, temperature and irradiation conditions, and to decrease with increasing relative humidity: γ0 = 1.2/(18.7 + RH1.1) (calculated using geometric surface area, with 30% estimated conservative uncertainty). An upper limit of 5% was found for the H2O2 forming pathway of the HO2 reaction with ATD surface. The results of the measurements indicate that HO2 loss on dust aerosol may be a non negligible sink for HOx species in the troposphere with the effect depending on specific local conditions.
Seasonal prediction of extreme precipitation events and frequency of rainy days over Costa Rica, Central America, using Canonical Correlation Analysis
Authors: Maldonado T. , Alfaro E. , Fallas-López B. , Alvarado L.
Published: April 2013

Abstract. High mountains divide Costa Rica, Central America, into two main climate regions, the Pacific and Caribbean slopes, which are lee and windward, respectively, according to the North Atlantic trade winds – the dominant wind regime. The rain over the Pacific slope has a bimodal annual cycle, having two maxima, one in May–June and the other in August-September-October (ASO), separated by the mid-summer drought in July. A first maximum of deep convection activity, and hence a first maximum of precipitation, is reached when sea surface temperature (SST) exceeds 29 °C (around May). Then, the SST decreases to around 1 °C due to diminished downwelling solar radiation and stronger easterly winds (during July and August), resulting in a decrease in deep convection activity. Such a reduction in deep convection activity allows an increase in down welling solar radiation and a slight increase in SST (about 28.5 °C) by the end of August and early September, resulting once again in an enhanced deep convection activity, and, consequently, in a second maximum of precipitation. Most of the extreme events are found during ASO. Central American National Meteorological and Hydrological Services (NMHS) have periodic Regional Climate Outlook Fora (RCOF) to elaborate seasonal predictions. Recently, meetings after RCOF with different socioeconomic stakeholders took place to translate the probable climate impacts from predictions. From the feedback processes of these meetings has emerged that extreme event and rainy days seasonal predictions are necessary for different sectors. As is shown in this work, these predictions can be tailored using Canonical Correlation Analysis for rain during ASO, showing that extreme events and rainy days in Central America are influenced by interannual variability related to El Niño-Southern Oscillation and decadal variability associated mainly with Atlantic Multidecadal Oscillation. Analyzing the geographical distribution of the ASO-2010 disaster reports, we noticed that they did not necessarily agree with the geographical extreme precipitation event distribution, meaning that social variables, like population vulnerability, should be included in the extreme events impact analysis.
The non-steady state oceanic CO2 signal: its importance, magnitude and a novel way to detect it
Authors: McNeil B. I. , Matear R. J.
Published: April 2013

Abstract. The role of the ocean has been pivotal in modulating rising atmospheric CO2 levels since the industrial revolution, sequestering nearly half of all fossil-fuel derived CO2 emissions. Net oceanic uptake of CO2 has roughly doubled between the 1960s (~1 Pg C yr−1) and 2000s (~2 Pg C yr−1), with expectations that it will continue to absorb even more CO2 with rising future atmospheric CO2 levels. However, recent CO2 observational analyses along with numerous model predictions suggest the rate of oceanic CO2 uptake is already slowing, largely as a result of a natural decadal-scale outgassing signal. This recent CO2 outgassing signal represents a significant shift in our understanding of the oceans role in modulating atmospheric CO2. Current tracer-based estimates for the ocean storage of anthropogenic CO2 assume the ocean circulation and biology is in steady state, thereby missing the new and potentially important "non-steady state" CO2 outgassing signal. By combining data-based techniques that assume the ocean is in a steady state, with techniques that constrain the net oceanic CO2 uptake signal, we show how to extract the non-steady state CO2 signal from observations. Over the entire industrial era, the non-steady state CO2 outgassing signal (~13 ± 10 Pg C) is estimated to represent about 9% of the total net CO2 inventory change (~142 Pg C). However, between 1989 and 2007, the non-steady state CO2 outgassing signal (~6.3 Pg C) has likely increased to be ~18% of net oceanic CO2 storage over that period (~36 Pg C). The present uncertainty of our data-based techniques for oceanic CO2 uptake limit our capacity to quantify the non-steady state CO2 signal, however with more data and better certainty estimates across a range of diverse methods, this important and growing CO2 signal could be better constrained in the future.
Horizontal distribution of Fukushima-derived radiocesium in zooplankton in the northwestern Pacific Ocean
Authors: Kitamura M. , Kumamoto Y. , Kawakami H. , Cruz E. C. , Fujikura K.
Published: April 2013

Abstract. The magnitude of the 9.0 Tohoku earthquake and the ensuing tsunami on 11 March 2011, inflicted heavy damage on the Fukushima Dai-ichi nuclear power plant (FNPP1). Fission products were emitted, falling over a broad range in the northern hemisphere, and water contaminated with radionuclides leaked into the ocean. In this study, we described the horizontal distribution of the Fukushima-derived radiocesium in zooplankton and in seawater in the western North Pacific Ocean (500–2100 km from the FNPP1) 10 months after the accident. 134Cs and 137Cs were detected in zooplankton and seawater from all the stations. Because of its short half-lives, 134Cs detected in our samples could only be derived from the FNPP1 accident. The highest 137Cs activity in zooplankton was same order of magnitude as that one month after the accident, and average activity was one or two orders of magnitude higher than 137Cs activities observed before the accident around Japan. Horizontally, the radiocesium activity concentrations in zooplankton were high at around 25° N while those in surface seawater were high at around the transition area between the Kuroshio and the Oyashio Currents (36–40° N). We observed subsurface radiocesium maxima in density range of the North Pacific Subtropical Mode Water and occurrence of many diel vertical migratory zooplanktons. These suggested that the high activity concentrations in the subtropical zooplankton at around 25° N were connected to the subsurface radiocesium and active vertical migration of zooplankton. However, the high activity concentrations of radiocesium in subsurface seawater did not necessarily follow the higher radiocesium activity in zooplankton. Biological characteristics of zooplankton community possibly influenced how large was contamination of radiocesium in the community but it is still unknown what kind of biological factors were important.
One-year, regional-scale simulation of 137Cs radioactivity in the ocean following the Fukushima Daiichi Nuclear Power Plant accident
Authors: Tsumune D. , Tsubono T. , Aoyama M. , Uematsu M. , Misumi K. , Maeda Y. , Yoshida Y. , Hayami H.
Published: April 2013

Abstract. A series of accidents at the Fukushima Dai-ichi Nuclear Power Plant following the earthquake and tsunami of 11 March 2011 resulted in the release of radioactive materials to the ocean by two major pathways, direct release from the accident site and atmospheric deposition. A 1 yr, regional-scale simulation of 137Cs activity in the ocean offshore of Fukushima was carried out, the sources of radioactivity being direct release, atmospheric deposition, and the inflow of 137Cs deposited on the ocean by atmospheric deposition outside the domain of the model. Direct releases of 131I, 134Cs, and 137Cs were estimated for 1 yr after the accident by comparing simulated results and measured activities. The estimated total amounts of directly released 131I, 134Cs, and 137Cs were 11.1 ± 2.2 PBq, 3.5 ± 0.7 PBq, and 3.6 ± 0.7 PBq, respectively. The contributions of each source were estimated by analysis of 131I/137Cs and 134Cs/137Cs activity ratios and comparisons between simulated results and measured activities of 137Cs. Simulated 137Cs activities attributable to direct release were in good agreement with measured activities close to the accident site, a result that implies that the estimated direct release rate was reasonable, while simulated 137Cs activities attributable to atmospheric deposition were low compared to measured activities. The rate of atmospheric deposition onto the ocean was underestimated because of a~lack of measurements of deposition onto the ocean when atmospheric deposition rates were being estimated. Measured 137Cs activities attributable to atmospheric deposition helped to improve the accuracy of simulated atmospheric deposition rates. Simulated 137Cs activities attributable to the inflow of 137Cs deposited onto the ocean outside the domain of the model were in good agreement with measured activities in the open ocean within the model domain after June 2012. The contribution of inflow increased with time and was dominant (more than 99%) by the end of February 2012. The activity of directly released 137Cs, however, decreased exponentially with time and was detectable only in the coastal zone by the end of February 2012.
Altered phenology and temperature sensitivity of invasive annual grasses and forbs changes autotrophic and heterotrophic respiration rates in a semi-arid shrub community
Authors: Mauritz M. , Lipson D. L.
Published: April 2013

Abstract. Many invasions, like the wide-spread establishment of annual grasses and forbs in semi-arid shrublands, are associated with climate change. In order to predict ecosystem carbon (C) storage it is critical that we understand how invasion affects soil respiration (Rt). Because plants and microbes have different seasonal dynamics, determining the relative contribution of autotrophic (Ra) and heterotrophic (Rh) respiration provides critical insight into soil C processes. Using automated soil respiration measurements and root exclusion cores we evaluated the moisture and temperature sensitivity of Rt and Rh and calculated the contribution of Ra in native shrub and invaded areas. Invasion increased cumulative Rt by 40% from 695 (±51) g C m−2 under shrubs to 1050 g C m−2 (±44) in invaded areas. Cumulative Rh did not change but invasion altered the seasonal pattern of Rh. Throughout the season Rt and Rh responded positively to temperature increases when soils were wet and negatively when soils were dry. Invasion increased temperature sensitivity of Rt and Rh in wet soils and decreased temperature sensitivity in dry soils. The altered temperature sensitivity of invasives was attributed largely to differences in phenology. Early phenology of invasive grasses caused rapid Ra increases early in the season; late phenology of invasive forbs resulted in the surprising maintenance of diurnal Ra and Rh signals despite high temperatures and low soil moisture. Invasion extended the respiration season of the system. Ability of the invasive community to withstand high temperatures and drought could confer greater resilience if temperature and precipitation patterns in the region change. The high contribution of Ra by invasive annuals means ecosystem C storage will depend heavily on seasonal rainfall dynamics and productivity of invasive annuals. In semi-arid ecosystems even small scale changes in plant community composition alter Rt, Ra and Rh and should be considered when attempting to predict Rt.
Automated tracking of shallow cumulus clouds in large domain, long duration Large Eddy Simulations
Authors: Heus T. , Seifert A.
Published: April 2013

Abstract. This paper presents a method for feature tracking of fields of shallow cumulus convection in Large Eddy Simulations (LES) by connecting the projected cloud cover in space and time, and by accounting for splitting and merging of cloud objects. Existing methods tend to be either imprecise or, when using the full 3 dimensional spatial field, prohibitively expensive for large data sets. Compared to those 3-D methods, the current method reduces the memory footprint by up to a factor 100, while retaining most of the precision by correcting for splitting and merging events between different clouds. The precision of the algorithm is further enhanced by taking the vertical extent of the cloud into account. Furthermore, rain and subcloud thermals are also tracked, and links between clouds, their rain, and their subcloud thermals are made. The method compares well with results from the literature. Resolution and domain dependencies are also discussed. For the current simulations, the cloud size distribution converges for clouds larger than an effective resolution of 6Δx, and smaller than about 20% of the horizontal domains size.
Assessment of shallow subsurface characterisation with non-invasive geophysical methods at the intermediate hill-slope scale
Authors: Popp S. , Altdorff D. , Dietrich P.
Published: April 2013

Abstract. Hill-slopes of several hectares in size represent a difficult scale for subsurface characterisation, as these landscape units are well beyond the scope of traditional point-scale techniques. By means of electromagnetic induction (EMI) and gamma-ray spectroscopy, spatially distributed soil proxy data were collected from a heterogeneous hill-slope site. Results of EMI mapping using the EM38DD showed that soil electrical conductivity (ECa) is highly variable at both temporal and spatial scales. Calibration of the integral ECa signal to a specific target like soil moisture is hampered by the ambiguous response of EMI to the clay-rich hill-slope underground. Gamma-ray results were obtained during a single survey, along with EMI measurements and selected soil sampling. In contrast to ECa, a noticeable correlation between Total Count and K emission data and soil-water content seemed to be present. Relevant proxy variables from both methods were used for k means clustering in order to distinguish between hill-slope areas with different soil conditions. As a result, we obtained a suitable partition of hill-slope that was comparable with a previously obtained zonation model based on ecological factors.
On the use of the Stokes number to explain frictional tidal dynamics and water column structure in shelf seas
Authors: Souza A. J.
Published: April 2013

Abstract. In recent years coastal oceanographers have suggested using the "Strouhal" number or its inverse, the "Stokes" number, to describe the effect of bottom boundary layer turbulence on the vertical structure of both density and currents. These are defined as the ratios of the frictional depth (δ) to the water column depth (h) or vice versa. Although many researchers have mentioned that the effects of the earth's rotation should be important, they have tended to omit it. Rotation may have an important influence on tidal currents, as the frictional depth from a fully cyclonic to a fully anticyclonic tidal ellipse can vary by up to an order of magnitude at mid latitudes. The Stokes number might appear smaller for cyclonic current ellipses (larger for anticyclonic) than it is without rotation, resulting in frictional effects being underestimated (overestimated). Here, a way to calculate a Stokes number is proposed, in which the effect of the earth's rotation is taken into account. The standard Stokes and the rotational Stokes numbers are used as predictors for the position of the tidal mixing fronts in the Irish Sea. Results show that use of the rotational number improves the predictions of fronts in shallow cyclonic areas of the eastern Irish Sea. This suggests that the effect of rotation on the water column structure will be more important in shallow shelf seas and estuaries with strong rotational currents.
Variability in the air–sea interaction patterns and timescales within the south-eastern Bay of Biscay, as observed by HF radar data
Authors: Fontán A. , Esnaola G. , Sáenz J. , González M.
Published: April 2013

Abstract. Two high-frequency (HF) radar stations were installed on the coast of the south-eastern Bay of Biscay in 2009, providing high spatial and temporal resolution and large spatial coverage of currents in the area for the first time. This has made it possible to quantitatively assess the air–sea interaction patterns and timescales for the period 2009–2010. The analysis was conducted using the Barnett–Preisendorfer approach to canonical correlation analysis (CCA) of reanalysis surface winds and HF radar-derived surface currents. The CCA yields two canonical patterns: the first wind–current interaction pattern corresponds to the classical Ekman drift at the sea surface, whilst the second describes an anticyclonic/cyclonic surface circulation. The results obtained demonstrate that local winds play an important role in driving the upper water circulation. The wind–current interaction timescales are mainly related to diurnal breezes and synoptic variability. In particular, the breezes force diurnal currents in waters of the continental shelf and slope of the south-eastern Bay. It is concluded that the breezes may force diurnal currents over considerably wider areas than that covered by the HF radar, considering that the northern and southern continental shelves of the Bay exhibit stronger diurnal than annual wind amplitudes.