bluuebunny/crossref_metadata_2025 huggingface dataset:
Impacts of aerosol particles on the microphysical and radiative properties of stratocumulus clouds over the southeast Pacific Ocean
Authors: Twohy C. H. , Anderson J. R. , Toohey D. W. , Andrejczuk M. , Adams A. , Lytle M. , George R. C. , Wood R. , Saide P. , Spak S. , Zuidema P. , Leon D.
Published: March 2013

Abstract. The southeast Pacific Ocean is covered by the world's largest stratocumulus cloud layer, which has a strong impact on ocean temperatures and climate in the region. The effect of anthropogenic sources of aerosol particles on the stratocumulus deck was investigated during the VOCALS field experiment. Aerosol measurements below and above cloud were made with a ultra-high sensitivity aerosol spectrometer and analytical electron microscopy. In addition to more standard in-cloud measurements, droplets were collected and evaporated using a counterflow virtual impactor (CVI), and the non-volatile residual particles were analyzed. Many flights focused on the gradient in cloud properties on an E-W track along 20° S from near the Chilean coast to remote areas offshore. Mean statistics, including their significance, from eight flights and many individual legs were compiled. Consistent with a continental source of cloud condensation nuclei, below-cloud accumulation-mode aerosol and droplet number concentration generally decreased from near shore to offshore. Single particle analysis was used to reveal types and sources of the enhanced particle number that influence droplet concentration. While a variety of particle types were found throughout the region, the dominant particles near shore were partially neutralized sulfates. Modeling and chemical analysis indicated that the predominant source of these particles in the marine boundary layer along 20° S was anthropogenic pollution from central Chilean sources, with copper smelters a relatively small contribution. Cloud droplets were smaller in regions of enhanced particles near shore. However, physically thinner clouds, and not just higher droplet number concentrations from pollution, both contributed to the smaller droplets. Satellite measurements were used to show that cloud albedo was highest 500–1000 km offshore, and actually slightly lower closer to shore due to the generally thinner clouds and lower liquid water paths there. Thus, larger scale forcings that impact cloud macrophysical properties, as well as enhanced aerosol particles, are important in determining cloud droplet size and cloud albedo. Differences in the size distribution of droplet residual particles and ambient aerosol particles were observed. By progressively excluding small droplets from the CVI sample, we were able to show that the larger drops, some of which may initiate drizzle, contain the largest aerosol particles. Geometric mean diameters of droplet residual particles were larger than those of the below-cloud and above cloud distributions. However, a wide range of particle sizes can act as droplet nuclei in these stratocumulus clouds. A detailed LES microphysical model was used to show that this can occur without invoking differences in chemical composition of cloud-nucleating particles.
Monitoring volcanic ash cloud top height through simultaneous retrieval of optical data from polar orbiting and geostationary satellites
Authors: Zakšek K. , Hort M. , Zaletelj J. , Langmann B.
Published: March 2013

Abstract. Volcanic ash cloud-top height (ACTH) can be monitored on the global level using satellite remote sensing. Here we propose a photogrammetric method based on the parallax between data retrieved from geostationary and polar orbiting satellites to overcome some limitations of the existing methods of ACTH retrieval. SEVIRI HRV band and MODIS band 1 are a good choice because of their high resolution. The procedure works well if the data from both satellites are retrieved nearly simultaneously. MODIS does not retrieve the data at exactly the same time as SEVIRI. To compensate for advection we use two sequential SEVIRI images (one before and one after the MODIS retrieval) and interpolate the cloud position from SEVIRI data to the time of MODIS retrieval. The proposed method was tested for the case of the Eyjafjallajökull eruption in April 2010. The parallax between MODIS and SEVIRI data can reach 30 km, which implies an ACTH of approximately 12 km at the beginning of the eruption. At the end of April eruption an ACTH of 3–4 km is observed. The accuracy of ACTH was estimated to be 0.6 km.
Sulfate-nitrate-ammonium aerosols over China: response to 2000–2015 emission changes of sulfur dioxide, nitrogen oxides, and ammonia
Authors: Wang Y. , Zhang Q. Q. , He K. , Zhang Q. , Chai L.
Published: March 2013

Abstract. We use a chemical transport model to examine the change of sulfate-nitrate-ammonium (SNA) aerosols over China due to anthropogenic emission changes of their precursors (SO2, NOx and NH3) from 2000 to 2015. From 2000 to 2006, annual mean SNA concentrations increased by about 60% over China as a result of the 60% and 80% increases in SO2 and NOx emissions. During this period, sulfate is the dominant component of SNA over South China (SC) and Sichuan Basin (SCB), while nitrate and sulfate contribute equally over North China (NC). Based on emission reduction targets in the 12th (2011–2015) Five-Year Plan (FYP), China's total SO2 and NOx emissions are projected to change by −16% and +16% from 2006 to 2015, respectively. The amount of NH3 emissions in 2015 is uncertain, given the lack of sufficient information on the past and present levels of NH3 emissions in China. With no change in NH3 emissions, SNA mass concentrations in 2015 will decrease over SCB and SC compared to their 2006 levels, but increase over NC where the magnitude of nitrate increase exceeds that of sulfate reduction. This suggests that the SO2 emission reduction target set by the 12th FYP, although effective in reducing SNA over SC and SCB, will not be successful over NC, for which NOx emission control needs to be strengthened. If NH3 emissions are allowed to keep their recent growth rate and increase by +16% from 2006 to 2015, the benefit of SO2 reduction will be completely offset over all of China due to the significant increase of nitrate, demonstrating the critical role of NH3 in regulating nitrate. The effective strategy to control SNA and hence PM2.5 pollution over China should thus be based on improving understanding of current NH3 emissions and putting more emphasis on controlling NH3 emissions in the future.
A new method for nocturnal aerosol measurements with a lunar photometer prototype
Authors: Barreto A. , Cuevas E. , Damiri B. , Guirado C. , Berkoff T. , Berjón A. J. , Hernández Y. , Almansa F. , Gil M.
Published: March 2013

Abstract. This paper presents the preliminary results of nocturnal Aerosol Optical Depth (τa) and Angström Exponent (α) obtained from a new lunar photometer prototype, trade name Cimel CE-318U. Due to the variation of the moon's illumination inherent to the lunar cycle, the typical Langley-plot Method used in solar photometry to calibrate these instruments cannot be applied. In this paper, we propose three different methods to carry out the lunar-photometer calibration. In order to validate the results, we have selected three events which encompass seven nights and ten days under different atmospheric conditions, including several saharan dust intrusions episodes. Method#1 is introduced in this work as a modification of the usual Langley Method. This technique, called Lunar-Langley Method, requires the extraterrestrial irradiances from a lunar irradiance model, providing similar accuracies on τa to those of AERONET (±0.01–0.02). It makes comparable daytime and nighttime measurements. Method#2 consists of transferring the current calibration from a master used by sunphotometers. Its results are again within the limit of accuracy expected for the instrument. Method#3 uses an integrating sphere and the methodology proposed by Li et al. (2008) to determine sky calibration coefficients (Cj) and the instrument's solid angle field-of-view (Ω), respectively. We observe significant τa differences between Method#1 and #3 (up to 0.07), which might be attributed to the errors propagation in Method#3. The good results obtained from the comparison against a second CE-318U prototype, and against daytime data from a Precision Filter Radiometer (PFR), constitute a valuable assessment of CE-318U performance. Results of α and its spectral variation (δ α) show good agreement between daytime and nighttime, being able to identify the aerosol properties associated with each event.
Response of Nodularia spumigena to pCO2 – Part 3: Turnover of phosphorus compounds
Authors: Unger J. , Endres S. , Wannicke N. , Engel A. , Voss M. , Nausch G. , Nausch M.
Published: March 2013

Abstract. Diazotrophic cyanobacteria form extensive summer blooms in the Baltic Sea driving the surrounding surface waters into phosphate limitation. One of the main bloom-forming species is the heterocystous cyanobacterium Nodularia spumigena. N. spumigena exhibits accelerated uptake of phosphate through the release of the extracellular enzyme alkaline phosphatase whose activity also serves as an indicator of the hydrolysis of dissolved organic phosphorus (DOP). The present study investigated the utilisation of DOP and its compounds (e.g., ATP) by N. spumigena during growth under different CO2 concentrations, in order to estimate potential consequences of ocean acidification on the cell's supply with phosphorus (P). Cell growth, the phosphorus pool, and four DOP compounds (ATP, DNA, RNA, and phospholipids) were determined in three setups with different CO2 concentrations (average 341 μatm, 399 μatm, and 508 μatm) during a 15-day batch experiment. The results showed stimulated growth of N. spumigena and a rapid depletion of dissolved inorganic phosphorus (DIP) in all pCO2 treatments. DOP uptake was enhanced by a factor of 1.32 at 399 μatm and of 2.25 at 508 μatm compared to the lowest CO2 concentration. Among the measured DOP compounds, none was found to accumulate preferentially during the incubation or in response to a specific pCO2 treatment. However, at the beginning 61.9 ± 4.3% of total DOP were not characterised but comprised the most utilised fraction. This is demonstrated by the decrement of this fraction to 27.4 ± 9.9% of total DOP during the growth phase with a preference at high pCO2. Our results indicate a stimulated growth of diazotrophic cyanobacteria at increasing CO2 concentrations which is accompanied by increasing utilisation of DOP as an alternative P source.
A model of hydrological and mechanical feedbacks of preferential fissure flow in a slow-moving landslide
Authors: Krzeminska D. M. , Bogaard T. A. , Malet J.-P. , van Beek L. P. H.
Published: March 2013

Abstract. The importance of hydrological processes for landslide activity is generally accepted. However, the relationship between precipitation, hydrological responses and movement is not straightforward. Groundwater recharge is mostly controlled by the hydrological material properties and the structure (e.g., layering, preferential flow paths such as fissures) of the unsaturated zone. In slow-moving landslides, differential displacements caused by the bedrock structure complicate the hydrological regime due to continuous opening and closing of the fissures, creating temporary preferential flow paths systems for infiltration and groundwater drainage. The consecutive opening and closing of fissure aperture control the formation of a critical pore water pressure by creating dynamic preferential flow paths for infiltration and groundwater drainage. This interaction may explain the seasonal nature of the slow-moving landslide activity, including the often observed shifts and delays in hydrological responses when compared to timing, intensity and duration of precipitation. The main objective of this study is to model the influence of fissures on the hydrological dynamics of slow-moving landslide and the dynamic feedbacks between fissures, hydrology and slope stability. For this we adapt the spatially distributed hydrological and slope stability model (STARWARS) to account for geotechnical and hydrological feedbacks, linking between hydrological response of the landside and the dynamics of the fissure network and applied the model to the hydrologically controlled Super-Sauze landslide (South French Alps).
Manifestation of two meddies in altimetry and sea-surface temperature
Authors: Bashmachnikov I. , Boutov D. , Dias J.
Published: March 2013

Abstract. Two meddies were identified in the Iberian Basin using shipboard ADCP (Meddy 1) and Argo float (Meddy 2) in contrasting background conditions. Meddy 1 was observed while interacting with the Azores Current (AzC), while Meddy 2 was observed in a much calmer dynamical background, north from the AzC jet. In both cases the meddies formed a clear anticyclonic surface signal, detectable in altimetry as well as in sea-surface temperature (SST). Analysis of the in situ observations of the dynamic signal over Meddy 1 showed that the signal, generated by the moving meddy, dominated the AzC dynamics at least up to the base of the seasonal thermocline even at the late stages of its interaction with the jet. The centre of rotation of the surface signal was shifted south-westward from the axis of the meddy by about 18 km, and its dynamic radius was 2 times bigger than that of the meddy. In the centre of the anticyclonic surface signals of both meddies, SST was colder than that of the surrounding water, in contrast to warm SST anomalies in the cores of surface anticyclones generated by meandering surface currents. The latter difference gives ground for identification of meddies (as well as other sub-surface anticyclones) in comparatively dynamically calm regions using coupled altimetry–SST remote sensing data. An identification of Meddy 1 prior to the shipboard ADCP measurements was the first successful experience. At the same time, SST anomalies over the meddies were rather weak, often unstable and statistically significant only over periods of months.
Cascading water underneath Wilkes Land, East Antarctic Ice Sheet, observed using altimetry and digital elevation models
Authors: Flament T. , Berthier E. , Rémy F.
Published: March 2013

Abstract. We describe a major subglacial lake drainage close to the ice divide in Wilkes Land, East Antarctica, and the subsequent cascading of water underneath the ice sheet toward the coast. To analyze the event, we combined altimetry data from several sources and bedrock data. We estimated the total volume of water that drained from Lake CookE2 by differencing digital elevation models (DEM) derived from ASTER and SPOT5 stereo-imagery. With 5.2 ± 0.5 km3, this is the largest single subglacial drainage event reported so far in Antarctica. Elevation differences between ICESat laser altimetry and the SPOT5 DEM indicate that the discharge lasted approximately 2 yr. A 13-m uplift of the surface, corresponding to a refilling of about 0.64 ± 0.32 km3, was observed between the end of the discharge in October 2008 and February 2012. Using Envisat radar altimetry, with its high 35-day temporal resolution, we monitored the subsequent filling and drainage of connected subglacial lakes located downstream. In particular, a transient temporal signal can be detected within the theoretical 500-km long flow paths computed with the BEDMAP2 data set. The volume of water traveling in this wave is in agreement with the volume that drained from Lake CookE2. These observations contribute to a better understanding of the water transport beneath the East Antarctic ice sheet.
Significance of Autotaxin Activity and Overexpression in Comparison to Soluble Intercellular Adhesion Molecule in Thyroid Cancer
Authors: Hassan Azza M. , El-Din Mohamed A. Alm , Nagy Hala , Ghoneem Naglaa , El-Heniedy Mohamed A. , Koteb Nessreen , El-Gohary Salah
Published: March 2013

Background

The objective of this study was to evaluate the role of autotaxin (ATX) activity and gene expression compared to soluble intercellular adhesion molecule-1 (sICAM-1) in thyroid carcinoma.

Patients and Methods

Sixty-five patients with thyroid swelling were included. There were 20 cases of simple multinodular goiter (group I), 15 cases of follicular adenoma (group II) and 30 cases of thyroid cancer (group III). Group III was further subdivided into negative and positive lymph nodes (group IIIa and IIIb; 22 and 8 cases, respectively). sICAM-1 concentration and ATX activity were measured using colorimetric enzyme-linked immunosorbent assay (ELISA), while ATX gene expression was detected by real-time polymerase chain reaction (PCR).

Results

sICAM-1 level, ATX activity and gene expression were significantly elevated in patients with thyroid carcinoma compared to other groups. The ATX activity showed significantly higher sensitivity and specificity than sICAM-1 (100% and 97.1% vs 93.3% and 88.6%, respectively). Both sICAM-1 and ATX values were significantly higher in patients with positive lymph nodes compared to those without lymph node involvement (p<0.001). Higher levels of ATX activity and gene expression were significantly correlated with larger tumor size and undifferentiated pathological subtype in thyroid carcinoma. In this respect, ATX was superior to sICAM-1.

Conclusion

Our data suggest that ATX activity and gene expression are reliable diagnostic and prognostic tools in thyroid carcinoma compared to sICAM-1.
Risk Factors of Hypertension at UNRWA Primary Health Care Centers in Gaza Governorates
Authors: Abed Y. , Abu-Haddaf S.
Published: March 2013

Universally, hypertension is a major public health problem. Identification of risk factors for hypertension supports intervention policies to minimize the disease morbidity and mortality. The main objective is to fill a gap in research literature by establishing baseline information for hypertension risk factors among Palestinians. Methods. A case control study was conducted at UNRWA health care services in Gaza Strip. A proportional systematic random sample of 120 cases matched with sex, and locality to 120 controls were chosen. Data was collected using a questionnaire which included socio-demographic data, lifestyle, and health profile. Collected data was analyzed using SPSS V13. Results. The most common modifiable risk factors of hypertension were physical inactivity (76.7% versus 15.9%), obesity (67.5% versus 29.2%), diabetes mellitus (19.2% versus 7.5%), and ex-smoking (15.5% versus 1%). Cases and controls show statistical significant differences in values for the lipid profile. Hypertension was significantly associated with low socio economic status, education, and employment. The most common non-modifiable risk factors were age, and family history (85.8% versus 71.7%). Multiple logistic analysis controlling for age showed that significant predictors of hypertension were obesity, physical inactivity, low monthly income and family history. Conclusion. Most of the identified hypertension risk factors are preventable.
Need for Cognition Is Related to the Rejection (but Not the Acceptance) of False Memories
Authors: LEDING JULIANA K.
Published: March 2013

Need for cognition (NFC) and rates of false recognition were studied in the context of the memory conjunction paradigm. Past research has shown that NFC is related to false recognition and false recall (Graham, 2007; Leding, 2011) in the Deese–Roediger–McDermott (DRM) paradigm, with high-NFC people experiencing more false memories. The present study extended this research to determine whether the findings of high-NFC people experiencing higher levels of false memories could be extended to other false memory paradigms. The present study also examined rates of high-confidence rejections of lures and recollection rejection responses. It was found that there were no significant differences for high- and low-NFC people in false recognition but that high-NFC people were more likely to use high-confidence rejections and have recollection rejection responses when they did reject lures.
Separate Pathway Characteristics of Numerical Surface Form Processing: Evidence From Operand-Related Error Effects
Authors: Zhang Ming-Liang , Si Ji-Wei , Zhu Xiao-Wen
Published: March 2013

Two perspectives compete to explain how the surface form of digits affects cognitive processing of numerical magnitude; one argues for a common pathway and the other for separate pathways. This study examined the operand-related error effect in simple multiplication operations using different combinations of visually presented Arabic digits and auditorily presented Mandarin number words. The study suggested two conclusions, both consistent with the separate pathway perspective. First, the numerical surface form (Arabic digits, spoken Mandarin number words) affected retrieval. That is, surface properties were maintained as specific codes throughout processing. Second, the phonological code activated by spoken Mandarin number words interfered with activation of answers during retrieval.
Contextual Influences on Dynamic Facial Expressions
Authors: Marian Diane E. , Shimamura Arthur P.
Published: March 2013

Participants viewed dynamic facial expressions that moved from a neutral expression to varying degrees of angry, happy, or sad or from these emotionally expressive faces to neutral. A contrast effect was observed for expressions that moved to a neutral state. That is, a neutral expression that began as angry was rated as having a mildly positive expression, whereas the same neutral expression was rated as negatively valenced when it began with a smile. In Experiment 2, static expressions presented sequentially elicited contrast effects, but they were weaker than those following dynamic expressions. Experiment 3 assessed a broad range of facial movements across varying degrees of angry and happy expressions. We observed momentum effects for movements that ended at mildly expressive points (25% and 50% expressive). For such movements, affect ratings were higher, as if the perceived expression moved beyond their endpoint. Experiment 4 assessed sad facial expressions and found both contrast and momentum effects for dynamic expressions to and from sad faces. These findings demonstrate new and potent contextual influences on dynamic facial expressions and highlight the importance of facial movements in social–emotional communication.
The Horizontal–Vertical Curvature Illusion in Touch Is Present in Three-Dimensional Objects and Raised Lines
Authors: Heller Morton A. , Smith Amy , Schnarr Rita , Larson Jennifer , Ballesteros Soledad
Published: March 2013

The present study compared the strength of the horizontal–vertical illusion in blindfolded sighted people with raised-line curves and three-dimensional (3-D) objects. Although the horizontal– vertical curvature illusion has been reported with raised-line stimuli in both vision and touch, it was not known whether similar haptic distortion would be found with 3-D objects. Similar overestimation of verticals was found with both types of stimuli in Experiment 1. Experiment 2 used bimanual unrestricted exploration at the body midline and stimuli horizontal on the table surface or in the frontal plane. In Experiment 2, illusion strength was substantially stronger when the stimuli were frontal and diminished overall for the horizontal group. The horizontal– vertical illusion was strong with optimal methods of presentation (free bimanual exploration) in Experiment 2, even where radial–tangential scanning could not be a causal factor in the frontal group. The results suggest that illusory distortion in haptics is not the result of the use of raised lines, and these patterns can be effective surrogates for 3-D objects.
Alternative rooting induction of semi-hardwood olive cuttings by several auxin-producing bacteria for organic agriculture systems
Authors: Montero-Calasanz M. C. , Santamaría C. , Albareda M. , Daza A. , Duan J. , Glick B. R. , Camacho M.
Published: March 2013

Southern Spain is the largest olive oil producer region in the world. In recent years organic agriculture systems have grown exponentially so that new alternative systems to produce organic olive cuttings are needed. Several bacterial isolates, namely Pantoea sp. AG9, Chryseobacterium sp. AG13, Chryseobacterium sp. CT348, Pseudomonas sp. CT364 and Azospirillum brasilense Cd (ATCC 29729), have been used to induce rooting in olive semi-hardwood cuttings of Arbequina, Hojiblanca and Picual cultivars of olive (Olea europea L). The first four strains were previously selected as auxin-producing bacteria and by their ability to promote rooting in model plants. They have been classified on the basis of their 16S rDNA gene sequence. The known auxin producer A. brasilense Cd strain has been used as a reference. The inoculation of olive cuttings was performed in two different ways: (i) by dipping cuttings in a liquid bacterial culture or (ii) by immersing them in a paste made of solid bacterial inoculant and sterile water. Under nursery conditions all of the tested bacterial strains were able to induce the rooting of olive cuttings to a similar or greater extent than the control cuttings treated with indole-3-butyric acid (IBA). The olive cultivars responded differently depending on the bacterial strain and the inoculation method. The strain that consistently gave the best results was Pantoea sp. AG9, the only one of the tested bacterial strains to express the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase. The results are also discussed in terms of potential commercial interest and nursery feasibility performance of these strains.
Effect of gender, housing density and the interaction on growth performance and carcass and meat quality of pigs slaughtered at 110 kg body weight
Authors: Serrano M. P. , Cámara L. , Morales J. I. , Berrocoso J. D. , López Bote C. J. , Mateos G. G.
Published: March 2013

A total of 228 crossbred pigs were used to investigate the effect of gender (gilts and barrows), density at housing (0.84 and 0.76 m2/pig) and the interaction on growth performance and carcass and merit from 19.4 to 110 kg body weight. Feed intake of gilts increased as the space allowance decreased but no effect was observed in barrows (p<0.05 for the interaction). However, no interaction was observed for average daily gain or feed-to-gain ratio. Barrows had 2.4% less (p<0.01) carcass lean percentage but 9% more (p<0.05) intramuscular fat content than gilts. The concentration of linoleic acid in the outer layer of backfat was higher (p<0.05) for gilts than for barrows when pigs were allocated at 0.84 m2/pig, but no differences were observed at 0.76 m2/pig. Also, barrows had 2.7% more (p<0.05) total saturated fatty acids (SFA) in the outer layer of backfat and lower monounsaturated fatty acids (MUFA) (p<0.01) and linoleic acid (p<0.05) content in the inner layer than gilts. Housing density did not affect any of the carcass quality traits studied but an increase in space allowance decreased (p<0.05) MUFA content in both layers. Pigs allocated at 0.84 m2/pig tended (p<0.10) to have higher SFA content in the inner layer than pigs allocated at 0.76 m2/pig. We concluded that gilts and barrows respond differently to space allocation in respect to feed intake and unsaturation of backfat. Housing density did not affect growth performance of pigs slaughtered at 110 kg but MUFA content decreased with increases in space allowance.
Contractual arrangements and food quality certifications in the Mexican avocado industry
Authors: Arana-Coronado J. J. , Bijman J , Omta O. , Oude Lansink A. G. J. M.
Published: March 2013

The adoption of private quality certifications in agrifood supply chains often requires specific investments by producers which can be safeguarded by choosing specific contractual arrangements. Based on a survey data from avocado producers in Mexico, this paper aims to analyze the impact of transaction costs and relationship characteristics of the joint choice of contractual arrangements and quality certifications. Using a bivariate probit model, it shows that a producer’s decision to adopt private quality certifications is directly linked to high levels of asset specificity and price. In order to ensure the high level of specificity under the presence of low levels of price uncertainty, producers have relied on relational governance supported by the expectation of continuity in their bilateral relationships with buyers.
Aplicabilidad del método de elementos finitos al análisis de las tensiones producidas en soleras de hormigón debido a las cargas transmitidas por los neumáticos de los tractores agrícolas
Authors: Malón H. , García-Ramos F. J. , Hernandez P. , Vidal M. , Bone A.
Published: March 2013

En relación con el dimensionado de soleras de hormigón apoyadas sobre el suelo, existen metodologías rigurosas para el cálculo de las tensiones de trabajo, basadas en la teoría de Westergaard, pero desarrolladas para vehículos industriales (coches, camiones y carretillas elevadoras). En las soleras de edificios agrícolas, el vehículo más utilizado es el tractor agrícola, que dispone de neumáticos de elevada anchura y diámetro, pero con una superficie de contacto reducida. En este artículo se ha abordado el estudio de las tensiones generadas en las soleras de hormigón por las cargas transmitidas por los neumáticos de los tractores agrícolas utilizando el método de elementos finitos (FEM). Para ello, se han estudiado las cargas transmitidas por los neumáticos del eje trasero de tres tractores. En paralelo, se ha realizado el mismo estudio utilizando la metodología de cálculo clásica de Westergaard. Como paso previo se ha justificado la utilización del FEM realizando una validación de cálculo de soleras para vehículos tradicionales industriales (carretillas elevadoras) en comparación con métodos validados para ese tipo de vehículos (Portland Cement Association, PCA) y con la teoría clásica de Westergaard. Como resultado se puede concluir que el FEM es una herramienta válida para analizar las tensiones generadas por las cargas transmitidas por los neumáticos de los tractores agrícolas sobre soleras de hormigón apoyadas sobre el terreno.
An approach to costs and energy consumption in private urban Spanish Mediterranean landscapes from a simplified model in sprinkle irrigation
Authors: Arbat G. , Pujol J. , Pelegrí M. , Puig-Bargués J. , Duran-Ros M. , Ramírez de Cartagena F.
Published: March 2013

The number of private gardens has increased in recent years, creating a more pleasant urban model, but not without having an environmental impact, including increased energy consumption, which is the focus of this study. The estimation of costs and energy consumption for the generic typology of private urban gardens is based on two simplifying assumptions: square geometry with surface areas from 25 to 500 m2 and hydraulic design with a single pipe. In total, eight sprinkler models have been considered, along with their possible working pressures, and 31 pumping units grouped into 5 series that adequately cover the range of required flow rates and pressures, resulting in 495 hydraulic designs repeated for two climatically different locations in the Spanish Mediterranean area (Girona and Elche). Mean total irrigation costs for the locality with lower water needs (Girona) and greater needs (Elche) were € 2,974 ha-1 yr-1 and € 3,383 ha-1 yr-1, respectively. Energy costs accounted for 11.4% of the total cost for the first location, and 23.0% for the second. While a suitable choice of the hydraulic elements of the setup is essential, as it may provide average energy savings of 77%, due to the low energy cost in relation to the cost of installation, the potential energy savings do not constitute a significant incentive for the irrigation system design. The low efficiency of the pumping units used in this type of garden is the biggest obstacle and constraint to achieving a high quality energy solution.
Oxidizable carbon and humic substances in rotation systems with brachiaria/livestock and pearl millet/no livestock in the Brazilian Cerrado
Authors: Loss A. , Pereira M. G. , Perin A. , Beutler S. J. , Anjos L. H. C. dos
Published: March 2013

The crop-livestock integration system significantly increases the carbon content in chemical fractions of soil organic matter (SOM). This study aimed to evaluate chemical indicators of SOM attributes for sites under brachiaria/livestock and pearl millet/no livestock in Goias, Brazil. A third area covered with natural Cerrado vegetation (Cerradão) served as reference. Soil was randomly sampled at 0-5, 5-10, 10-20 and 20-40 cm. Total organic carbon stocks (TOC), oxidizable carbon fractions (OCF) (F1>F2>F3>F4), carbon content in the humin (C-HUM), humic acid (C-HAF) and fulvic acid (C-FAF) fractions were evaluated. F1/F4, F1+F2/F3+F4, C-HAF/C-FAF and (C-HAF+C-FAF)/C-HUM indices were calculated, as well as stocks chemical SOM fractions. Brachiaria/livestock produced greater TOC stocks than pearl millet/no livestock (0-5, 5-10 and 10-20 cm). In terms of OCF, brachiaria/livestock generally exhibited higher levels in F1, F2, F4 and F1/F4 than pearl millet/no livestock. C-HUM (0-10 cm) and C-HAF (0-20 cm) stocks were larger in brachiaria/livestock than pearl millet/no livestock. Compared to the Cerradão, brachiaria/livestock locations displayed higher values for TOC (5-10 and 10-20 cm), C-HAF and C-HAF/C-FAF (5-10 cm) stocks. TOC, C-HAF stock and OCF show that land management with brachiaria/livestock was more efficient in increasing SOM than pearl millet/no livestock. Moreover, when compared with pearl millet/no livestock, brachiaria/livestock provided a more balanced distribution of very labile (F1) and recalcitrant (F4) carbon throughout soil layers, greater SOM humification. Brachiaria/livestock leads to higher values of F1 and F4 in depth when compared to pearl millet/livestock and provides a more homogeneous distribution of C-FAF and C-HAF in depth compared to Cerradão.
Short communication. First report of Eggplant mottled dwarf virus in China rose in southern Spain
Authors: Parrella G. , De Stradis A. , Greco B. , Villanueva F. , Fortes I. M. , Navas-Castillo J.
Published: March 2013

Eggplant mottled dwarf virus (EMDV, genus Nucleorhabdovirus, family Rhabdoviridae) is transmitted in nature by leafhoppers and its natural host range includes vegetable crops (eggplant, tomato, potato, pepper), ornamentals (pittosporum, honeysuckle, pelargonium) and wild plants (caper, Solanum nigrum). The prevalence of infections is generally very low. EMDV has been demonstrated to be the causal agent of a vein yellowing disease of China rose (Hibiscus rosa-sinensis) in southern Italy. In this work, four locations from Málaga and Granada provinces (southern Spain) were surveyed in 2011 to study the prevalence of EMDV infections in China rose by serological and molecular methods. Overall, EMDV was detected in 77.3% of the samples (33 out of 45 samples tested). Mechanical transmission tests and immunoelectron microscopy confirmed the presence of EMDV. The possible causes of such a high and unexpected prevalence are discussed. The use of molecular hibridization with an EMDV specific riboprobe is proposed for early screening of vegetative propagated China rose plants to avoid dissemination of infected material.
Mobile phones, risk and responsibility: Understanding children’s perceptions
Authors: Bond Emma
Published: March 2013

This study explores children's perceptions of risk and mobile phones in their everyday lives. Technological developments associated with capitalist society are entwined with the risk discourse, but little account has previously been taken of children's views in social analyses of risk. Based on the accounts of thirty young people in the UK aged between 11 – 17 this study adopts a social constructivist perspective to offer a theoretical framework which explores how children themselves actually use mobile phone technologies and understand and manage risk in their everyday lives.Implications of risk and mobile phones are reflected in current media discourse and contemporary public discussions. This research explores the relationship between young people's use of mobile phone technology and the wider theoretical debates about risk, technology and subjectivity. It provides insight into the social aspects of risk and mobile phones in contemporary childhoods.The children in the research were reflexive in their understanding of risk and mobile phones and actively managed risk through their mobile phone use. Their accounts highlight the complex, multifarious relationships of the heterogeneous networks of the technical, the social and the natural that constitute children's everyday lives.
Media Clips: A Rare July? – Fibonacci Takes to the Air
Authors: Jones Michael A. , Shelton Brittany
Published: March 2013

This year [2011], July has 5 Fridays, 5 Saturdays and 5 Sundays. This happens once every 823 years.
Why Is the Midpoint an Average?
Authors: Bu Lingguo
Published: March 2013

The relationship between a midpoint and an average showcases the interplay between procedural knowledge and conceptual knowledge in learning mathematics for teaching.
Sorting Out Ideas about Function
Authors: Hillen Amy F. , Malik LuAnn
Published: March 2013

A card-sorting task can help students extend their understanding of functions and functional relationships.
Redeem Reasoning
Authors: Chang Kuo-Liang
Published: March 2013

This opinion piece discusses how simplicity, ease, and efficiency—in the guise of shortcuts, tips, and packed procedures—kill mathematical reasoning.
Sailor Monkeys
Authors: Baer Sherri L. , Mooney Edward S.
Published: March 2013

Two problems involving grouping invite students to devise their own model and strategies.
Bingo! Select Games for Mathematical Thinking
Authors: Jackson Christa , Taylor Cynthia , Buchheister Kelley
Published: March 2013

Incorporating math games into the classroom will help your students become motivated problem solvers.
Transformations and Handheld Technology
Authors: Beaudrie Brian P. , Boschmans Barbara
Published: March 2013

Three transformation activities are completed by eighth-grade students who do not have access to a computer but can access handheld technology. Three activity sheets are included.
Math For Real:The Half-Lives of Medicines
Authors: Hoslar Alyssa
Published: March 2013

Calculating a half-life, the approximate time it takes for the body to remove one-half the active ingredient in a medicine, provides the real-life tie-in to this activity.
Mireille Havet, diariste et toxicomane
Authors: Bergeron Patrick
Published: March 2013

Cet article propose d’examiner les liens entre la toxicomanie et la pratique d’écriture du journal intime à partir de l’exemple de Mireille Havet (1898-1932). Nous mettrons en place quelques repères biographiques et historiques qui nous permettront ensuite de nous concentrer sur le Journal d’Havet. Nous voulons démontrer qu’une dynamique duelle s’y module : l’introspection évolue parallèlement avec une autodestruction que la dépendance à la drogue a rendue irréversible.
The AFF4 scaffold binds human P-TEFb adjacent to HIV Tat
Authors: Schulze-Gahmen Ursula , Upton Heather , Birnberg Andrew , Bao Katherine , Chou Seemay , Krogan Nevan J , Zhou Qiang , Alber Tom
Published: March 2013

Human positive transcription elongation factor b (P-TEFb) phosphorylates RNA polymerase II and regulatory proteins to trigger elongation of many gene transcripts. The HIV-1 Tat protein selectively recruits P-TEFb as part of a super elongation complex (SEC) organized on a flexible AFF1 or AFF4 scaffold. To understand this specificity and determine if scaffold binding alters P-TEFb conformation, we determined the structure of a tripartite complex containing the recognition regions of P-TEFb and AFF4. AFF4 meanders over the surface of the P-TEFb cyclin T1 (CycT1) subunit but makes no stable contacts with the CDK9 kinase subunit. Interface mutations reduced CycT1 binding and AFF4-dependent transcription. AFF4 is positioned to make unexpected direct contacts with HIV Tat, and Tat enhances P-TEFb affinity for AFF4. These studies define the mechanism of scaffold recognition by P-TEFb and reveal an unanticipated intersubunit pocket on the AFF4 SEC that potentially represents a target for therapeutic intervention against HIV/AIDS.
What does it take to recruit and retain senior women faculty?
Authors: Watt Fiona M
Published: March 2013

eLife deputy editor Fiona M Watt recounts some of her personal experiences as a senior female academic in a male-dominated environment.
Polymer‐Based Magnetoelectric Materials
Authors: Martins Pedro , Lanceros‐Méndez Senentxu
Published: March 2013

Polymer‐based magnetoelectric (ME) materials are an interesting, challenging and innovative research field, that will bridge the gap between fundamental research and applications in the near future. Here, the current state of the art on the different materials, the used configurations for the development of sensors and actuators, as well as the main values of the ME coupling obtained for the different polymer‐based systems are summarized. Further, some of the specific applications that are being developed for those polymer‐based ME materials are addressed as well as the main advantages and remaining challenges in this research field.
Printed, Flexible, Organic Nano‐Floating‐Gate Memory: Effects of Metal Nanoparticles and Blocking Dielectrics on Memory Characteristics
Authors: Kang Minji , Baeg Kang‐Jun , Khim Dongyoon , Noh Yong‐Young , Kim Dong‐Yu
Published: March 2013

The effects of using a blocking dielectric layer and metal nanoparticles (NPs) as charge‐trapping sites on the characteristics of organic nano‐floating‐gate memory (NFGM) devices are investigated. High‐performance NFGM devices are fabricated using the n‐type polymer semiconductor, poly{[N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene)} (P(NDI2OD‐T2)), and various metal NPs. These NPs are embedded within bilayers of various polymer dielectrics (polystyrene (PS)/poly(4‐vinyl phenol) (PVP) and PS/poly(methyl methacrylate) (PMMA)). The P(NDI2OD‐T2) organic field‐effect transistor (OFET)‐based NFGM devices exhibit high electron mobilities (0.4–0.5 cm2 V−1 s−1) and reliable non‐volatile memory characteristics, which include a wide memory window (≈52 V), a high on/off‐current ratio (Ion/Ioff ≈ 105), and a long extrapolated retention time (>107 s), depending on the choice of the blocking dielectric (PVP or PMMA) and the metal (Au, Ag, Cu, or Al) NPs. The best memory characteristics are achieved in the ones fabricated using PMMA and Au or Ag NPs. The NFGM devices with PMMA and spatially well‐distributed Cu NPs show quasi‐permanent retention characteristics. An inkjet‐printed flexible P(NDI2OD‐T2) 256‐bit transistor memory array (16 × 16 transistors) with Au‐NPs on a polyethylene naphthalate substrate is also fabricated. These memory devices in array exhibit a high Ion/Ioff (≈104 ± 0.85), wide memory window (≈43.5 V ± 8.3 V), and a high degree of reliability.
Hydrodynamic separation of particles using pinched‐flow fractionation
Authors: Ashley John F. , Bowman Christopher N. , Davis Robert H.
Published: March 2013

Rigid particles transported through a pinched‐flow fractionation (PFF) device are simulated using boundary‐integral methods (BIM). The PFF device separates particles by size using a bifurcated microfluidic channel. The critical flow ratio of the two input channels required to achieve complete separation of large and small particles decreases with increasing diameter of the larger particles relative to the pinch height, and is nearly independent of the smaller particle size. A narrow pinch with a square exit was shown to have the lowest critical flow ratio and was selected as the model device to be fabricated. Experiments conducted using this device confirm that the larger particles exit further from the top wall than do the smaller particles, due to steric exclusion, and the final exit positions are within a few percent of the simulation results. It is shown that BIM is a valuable tool in the design of microfluidic devices. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3444–3457, 2013
Premolar root morphology and metric variation in Pan troglodytes verus
Authors: Moore N. Collin , Skinner Matthew M. , Hublin Jean‐Jacques
Published: March 2013

Premolar root form remains an important taxonomic character in hominin alpha taxonomy. Variation in detailed aspects of root structure remains poorly characterized in extant apes. This limited comparative context hinders evaluations of the significance of root form variation in hominin systematics. Using micro‐computed tomography we examine morphological variation in premolars in 51 (n = 128 premolars) West African chimpanzees (Pan troglodytes verus). We categorize premolar root/canal form and number, based on the external root surface and pulp canal morphology, and test for a relationship between canal configuration and sex, jaw size, tooth/root size and cervix shape. Jaw size and root size/shape were quantified using standard metrics, and geometric morphometrics was used to examine root form and cervix shape. Our results confirm previous findings in external root form, but reveal previously undocumented variation in mandibular premolar canal number/form in this subspecies. The LP3 and UP4 exhibit variation in canal number/form, while the UP3 is restricted to external root configurations. The LP4 expresses only a single root/canal form. Generally, in LP3 and UP4 there is no correlation between canal form/number and sex, root size, and jaw size; UP4 canal variation covaried with cervix shape and size. Cervix size is significantly greater in three canal UP4s than two canal UP4s. Our results highlight canal form/number as an important aspect when characterizing root form. The implications of our results for the taxonomic utility of root form within the hominoid and hominin clades are discussed. Am J Phys Anthropol 150:632–646, 2013. © 2013 Wiley Periodicals, Inc.
Predictors of delayed‐type hypersensitivity to Candida albicans and anti‐epstein‐barr virus antibody among children in Kilimanjaro, Tanzania
Authors: Wander Katherine , Shell‐Duncan Bettina , Brindle Eleanor , O'Connor Kathleen
Published: March 2013

We evaluated sex, age, nutritional status, and infectious disease (ID) as predictors of two biomarkers of cell‐mediated immunity (CMI), delayed‐type hypersensitivity to Candida albicans (DTH‐Candida), and anti‐Epstein‐Barr virus antibody (EBV Ab), among 200 children in Kilimanjaro, Tanzania. DTH‐Candida, which decreases with compromised CMI, was positively associated with age (OR: 1.27; 95% CI: 1.02, 1.57) and triceps skinfold (TSF; OR: 1.16; 95% CI: 1.02, 1.26), and inversely associated with height‐for‐age Z score (HAZ; OR: 0.86; 95% CI: 0.68, 1.08) and diagnosed ID (OR: 0.48; 95% CI: 0.22, 1.08). There was significant interaction between TSF and ID: DTH‐Candida exhibited a strong inverse association with ID among children with low TSF (OR: 0.16; 95% CI: 0.05, 0.50) and a strong positive association with TSF among children with ID (OR: 2.64; 95% CI: 1.29, 5.42). EBV Ab, which increases with compromised CMI, was inversely associated with male sex (β: −0.47; 95% CI: −0.70, −0.24) and TSF (β: −0.04; 95% CI: −0.08, 0.00), and positively associated with HAZ (β: 0.06; 95% CI: −0.03, 0.15). Among males, EBV Ab was positively associated with anemia. Among normal HAZ children, EBV Ab was inversely associated with TSF. There was no association between DTH‐Candida and EBV Ab. While DTH‐Candida provides a direct measure of CMI, our results suggest that interpretation of EBV‐Ab among Kilimanjaro children was complicated by its indirect relationship with CMI. Among our sample, CMI increased with age and adequate nutrition and was compromised during acute ID. The suggestive CMI‐compromising effect of increasing height‐for‐age may bear further exploration. Am J Phys Anthropol 151:183–190, 2013. © 2013 Wiley Periodicals, Inc.