Upward Gradient Research Articles

Effect of strain gradient and interface engineering on the high-temperature energy storage capacitors

The miniaturization and high integration of electronic devices pose new requirements for the energy storage density and high-temperature performance of dielectric capacitors. For thin film materials, internal stress and the interface layer often show a significant impact on their energy storage performance. Therefore, the capacitors with different stress gradient sequences and different periods were designed by BaHf0.17Ti0.83O3 (BHTO17), BaHf0.25Ti0.75O3 (BHTO25), and BaHf0.32Ti0.68O3 (BHTO32) to investigate the effect of stress gradient and interface engineering on the energy storage characteristics. Dielectric thin film structures with upward gradient, downward gradient, and periodic upward gradient (4N) were constructed. The study found that the upward gradient structure had higher breakdown field strength than the downward gradient structure. This is because the upward gradient structure can effectively extend the ending electric field of the Ohmic conduction mechanism and delay the activation electric field of the F–N tunneling mechanism. The 4N structure had a slightly higher breakdown field strength (reaching 9.22 MV/cm) compared to the pure upward gradient structure. The 4N structure thin film also exhibited higher energy storage density (115.44 J/cm3) and wide temperature (−100 to 400 °C) characteristics. These findings provide important guidance and application value for improving the energy storage characteristics of dielectric capacitors at high temperatures through structural design.

Experimental study and statistical analysis of system performance parameters of a household freezer

The present research comprehensively examines the influences of different input variables, such as cabinet load level, ambient temperature, relative humidity, door opening time and day, on the output parameters of frosting amount, recovery time, and total energy consumption of the upright domestic freezer following the door opening operation. Moreover, a holistic statistical methodology, which is known as the GLM-ANOVA, was implemented for determining the parametric experimental results. Meanwhile, the effects of binary interactions between the input factors on the output parameters were extensively evaluated using statistical methods. As a consequence, the amount of frost increases with an upward gradient as the load level within the cabinet escalates from 25 °C to 32 °C. Both the duration of door openings and the relative humidity level have a double impact on the frosting. Moreover, the duration required for the system to recover from half load to full load more than doubles with an increase in ambient temperature from 25 °C to 32 °C. On the other hand, at an outdoor temperature of 25 °C, the recovery time demonstrates a close to linear relationship with the load level of the cabinet. Furthermore, the duration of door openings and the load capacity within the cabinet are considered two important factors that simultaneously influence the daily energy consumption. The infiltration of ambient air into the freezer compartment and the presence of moisture in the air substantially increase the energy consumption, especially when the relative humidity fluctuates between 30 % and 65 % and the door opening duration stretches from 10 to 20 s, respectively.

Fine Particulate Matter Exposure, Genetic Susceptibility, and the Risk of Incident Stroke: A Prospective Cohort Study.

Both genetic factors and environmental air pollution contribute to the risk of stroke. However, it is unknown whether the association between air pollution and stroke risk is influenced by the genetic susceptibilities of stroke and its risk factors. This prospective cohort study included 40 827 Chinese adults without stroke history. Satellite-based monthly fine particulate matter (PM2.5) estimation at 1-km resolution was used for exposure assessment. Based on 534 identified genetic variants from genome-wide association studies in East Asians, we constructed 6 polygenic risk scores for stroke and its risk factors, including atrial fibrillation, blood pressure, type 2 diabetes, body mass index, and triglyceride. The Cox proportional hazards model was applied to evaluate the hazard ratios and 95% CIs for the associations of PM2.5 and polygenic risk score with incident stroke and the potential effect modifications. Over a median follow-up of 12.06 years, 3147 incident stroke cases were documented. Compared with the lowest quartile of PM2.5 exposure, the hazard ratio (95% CI) for stroke in the highest quartile group was 2.72 (2.42-3.06). Among individuals at high genetic risk, the relative risk of stroke was 57% (1.57; 1.40-1.76) higher than those at low genetic risk. Although no statistically significant interaction was found, participants with both the highest PM2.5 and high genetic risk showed the highest risk of stroke, with ≈4× that of the lowest PM2.5 and low genetic risk group (hazard ratio, 3.55 [95% CI, 2.84-4.44]). Similar upward gradients were observed in the risk of stroke when assessing the joint effects of PM2.5 and genetic risks of blood pressure, type 2 diabetes, body mass index, atrial fibrillation, and triglyceride. Long-term exposure to PM2.5 was associated with a higher risk of incident stroke across different genetic susceptibilities. Our findings highlighted the great importance of comprehensive assessment of air pollution and genetic risk in the prevention of stroke.

The Influences of gradient color on the weight perception and stability perception: A preliminary study.

Gradient colors are widely used in product design. The variation of gradient colors muting a color as a series of steps from bright to dull creates a soft and gradual impression while also affecting people's perceptions. This study manipulates the types of gradient colors to explore the relationship between color gradients and perception of stability to determine whether weight perception plays a role. In the case of controlling for aesthetic differences, the study manipulated two types of color gradients (dark colors fading upward from the bottom versus downward from the top) and measured the perceptions of product stability. In the same hue, an upward gradient gives a stronger perception of stability. In addition, gradient colors significantly influence women's perception of stability more than men's. The study also investigated the mediating effect of weight perception: participants evaluated color fading-upward products with less weight relative to fading-downward colors. Furthermore, dark colors fading upward from the bottom lead to a stronger perception of weight, increasing the stability perception of the object. Finally, to aid future research, we discuss the practical implications of the current findings for areas such as sensory marketing, as well as possible directions for future research.

Influence of soil geomorphic factors on vegetation patterns in a model white sands ecosystem complex

Understanding the development of white sands ecosystems (WSEs) and their occurrence is critical for determining structural diversity in global biodiversity hotspots. WSE has fascinated ecologists for decades, with soil always opined to play a critical role in the development of complex ecosystem vegetation patterns. However, few to no studies have systematically investigated the effect of soil natural capital on the complex vegetation patterns in humid tropical forests that include the occurrence of open savannas. Instead, fires have been advanced as the key driver that sustains and expands open savannas in tropical forest biomes. In this study, we investigated the effects of soil geomorphic factors on vegetation patterns that range from tropical forests to open savannas in a model WSE complex known as the Aripo savannas scientific reserve. Soils were sampled from three white sands landscapes, each containing three vegetation types (open savanna, palm island, and marsh forest). Two transects of five soil sampling sites were randomly sampled in each vegetation type where stratified sampling of microtopography (hollows and flats) was applied. Samples were analyzed mainly for chemical properties, with some physical and mineralogical properties. Results showed patterns and relationships amongst vegetation types. Parent material was rich in quartz and zircon, poor in alkalis and sesquioxides, and resistant to weathering, forming white sands. Open savannas were significantly higher (P < 0.05) in coarse silt (32.8 %) and fine sand (34.1 %) and lower in fine silt and clay, suggesting a clear sorting associated with aeolian cover sands. In microtopographic areas, the upward gradient of water potential drove matter accumulation in hollows and upward translocation of elements under flat relief. The plant available nutrients and carbon were significantly lower (P < 0.05) in open savannas, demonstrating that plant nutrition was resource dependent. The Al concentration and pH matched with the vegetation patterns with a significantly decreasing Al concentration from forests (953 ppm) to open savannas (223 ppm) and significantly increasing pH from forests (3.7) to open savanna (4.1). Interestingly, the significantly lower Al concentration and higher pH in the open savanna suggest that these properties though more favorable in this locale, did not support tree growth and therefore were not predominant determinants of vegetation patterns. Quartz dominated all textural fractions, with clay fractions (which increased under forest) having higher levels of non-quartz minerals, e.g., silica. Silica, which is more degradable and initially provided more cations (nutrients and Al) to forest vegetation. Therefore, both texture (clay size) and minerals (clay minerals) together, degraded and delivered more cations. We conclude that WSEs in tropical forests developed on originally poor parent material. Since natural fire regimes are unlikely in this ecosystem, differences in vegetation distribution were not attributable to fires but are related to soil variability due to weathering and pre- weathering sorting. Most likely matter transport by lateral sheet water flow due to soil geomorphology is another factor controlling the development of vegetation patterns within WSE mainly found in humid tropical areas where wet season rainfall exceeds 2000 mm.

Оценка величины упругой разгрузки при маятниковом поверхностном пластическом деформировании

The elasticity of the hardened layer under pendulum surface plastic deformation is determined. Calculations are given using computer modeling Ansys 19.1 to estimate the influence of the main technological parameters and modes of pendulum SPD (Surface plastic deformation) by the amount of metal rate of upward gradient, which makes it possible to establish the actual amount of tension and ensure the accuracy of the diametrical dimensions of the hardened parts. The dependence of the elastic rise of the hardened layer on the physical and mechanical properties of the material is given.

Analysis of skelp deformation zones for the down trajectory of electrically welded pipes forming

Deformation zones along the down trajectories of skelps forming using the forming mill TESA10-50 (Pipe Electrical Welding Unit) were considered. For pipes with 50×1.5 mm diameter, strained conditions for forming zones were identified for different options of down trajectories length with the as-formed skelp initial position upward gradient within the range of H = 0÷50 mm. It was determined that increase in the down trajectory length contributed to the decrease in longitudinal strain values, however, it could not provide for forming within the allowable values along the entire forming zone of the mill. Reduction in the skelp curvature by 8÷13 % resulted in the longitudinal strains decrease at the skelp edge along the entire forming zone length.

Identifying Ecological Security Patterns Based on Ecosystem Service Supply and Demand Using Remote Sensing Products (Case Study: The Fujian Delta Urban Agglomeration, China)

As the global population increases and cities expand, increasing social needs and ecosystem degradation generally coexist, especially in China’s urban agglomerations. Identifying ecological security patterns (ESPs) for urban agglomerations serves as an effective way to sustain regional ecological security and promote harmonious ecological conservation and economic development. Focusing on the Fujian Delta Urban Agglomeration (FDUA) as an example, this study aims to present a framework for linking the supply and demand of ecosystem services (ESs) to identify ESPs in 2020. First, the ecological sources are delimited by coupling the supply and demand of four critical ESs (carbon storage, water provision, grain production, and outdoor recreation). Afterward, the resistance coefficient is modified using nighttime light intensity data and the ecological risk index, the second of which combines the effects of the soil erosion sensitivity index, the geological disaster risk index, and the land desertification risk index. Then, ecological corridors are determined by employing the minimum cumulative resistance method. With the integration of ecological sources and corridors, the ESPs of the FDUA can be identified. The results show a distinct supply–demand mismatch for ESs, with supply exhibiting an upward gradient from coastal cities to inland mountain cities and demand showing the opposite trend. The ESPs consist of 8359 km2 of ecological sources that are predominantly forests, 171 ecological corridors with a total length of 789.04 km, 34 pinch points, 26 barriers, and 48 break points. This paper presents a realizable approach for constructing ESPs for urban agglomerations, which will help decision makers optimize ecological sources and ecological protection policies.

Bioresorbable Depot for Sustained Release of Immunostimulatory Resiquimod in Suppressing Both Primary Triple-Negative Breast Tumors and Metastatic Occurrence.

In light of immune facilities trafficking toward the pathological sites along upward gradient of immunostimulatory cytokines, a localized resiquimod (Toll-like receptor 7/8 agonist) release depot was manufactured for pursuit of precision immunostimulation toward intractable triple-negative breast carcinoma. In principle, resiquimod/poly(lactic-co-glycolic acid) microspheres were fabricated and embedded into injectable and biodegradable poly(ethylene glycol) (PEG)-based hydrogel. The subsequent investigations approved persistent retention of immunostimulatory resiquimod in tumors upon peritumoral administration, which consequently led to localized and consistent secretion of immunostimulatory cytokines. Initially, not only innate tumor phagocytosis but also adaptive antitumor immunities were successfully cultivated for in situ suppression of the growth of primary solid tumors, more importantly, capable of inhibiting distant pulmonary metastasis, as evidenced by observation of enormous lymphocytes selectively gathering in the pulmonary artery. Hence, our presented study provided an important clinical indication of using immunostimulatory drugs to activate potent innate and adaptive antitumor immunities for precision antitumor therapy. Further immunomodulatory strategies, such as checkpoint blockage and tumor immunogenicity, could also be complementary for development of advanced antitumor immunotherapeutics in treatment of a number of intractable tumors.

Measuring hospital performances of regional referral hospitals in Tanzania

In Tanzania, regional referral hospitals (RRHs) play a major role in providing curative and diagnostic services and influence the performance of the entire health system. The results of a baseline survey conducted in 2015 to determine the status of RRHs in Tanzania indicated that there were many supportive supervisory and assessment tools for RRHs but none of them specifically focused on the performance of hospitals. In an endeavor to enhance the performance of RRHs, the Ministry of Health, Community Development, Gender, Elderly and Children (MoHCDGEC) and the President Office – Regional Administration and Local Government (PO-RALG) developed an external hospital performance assessment (EHPA) tool to analyze all aspects of the performance of RRHs. EHPA was started in 2017 to assess the performance of 28 RRHs in the country. This study examines the changes to the performance of the RRHs based on the introduction of the EHPA and the supportive interventions by the Ministry of Health. It is also studying the factors that influence the assessment of EHPA. As the results of this study, there is a great indication of the overall performance of RRHs being improved as observed from an upward gradient of average EHPA scores from 2017 to 2019 in all RRHs. This improvement is exemplified by the decrease in the standard deviation gap amongst RRHs. The three years (2017–2019) of consecutive assessment has also observed implicit competition in improving hospital services among Regional Referral Hospital Management Teams (RRHMTs) using the findings from the EHPA.

Carbon and nitrogen stable isotope variations in leaves of two grapevine cultivars (Chasselas and Pinot noir): Implications for ecophysiological studies

We investigated the within- and between-leaf variability in the carbon and nitrogen isotope composition (δ13C and δ15N) and total nitrogen (TN) content in two grapevine cultivars (Vitis vinifera cv. Chasselas and Pinot noir) field-grown under rain-fed conditions. The within-leaf variability was studied in discs sampled from base-to-tip and left and right regions from the margin to midrib. The intra- and interplant variability was studied by comparing leaves at different positions along the shoot (basal, median, apical). In leaves from both cultivars, a decrease in δ13C from base to tip was observed, which is in line with an upward gradient of stomatal density and chlorophyll concentration. Less important, but still significant differences were observed between the right and left discs. The leaf TN and δ15N values differed between cultivars, showed smaller variations than the δ13C values, and no systematic spatial trends. The intraleaf variations in δ13C, δ15N, and TN suggest that stomatal behavior, CO2 fixation, chlorophyll concentrations, and the chemical composition of leaf components were heterogeneous in the leaves. At the canopy scale, the apical leaves had less 13C and more 15N and TN than the basal leaves, indicating differences in their photosynthetic capacity and remobilizations from old, senescing leaves to younger leaves. Overall, this study demonstrates patchiness in the δ13C and δ15N values of grapevine leaves and species-specificity of the nitrogen assimilation and 15N fractionation. These findings suggest that care must be taken not to overinterpret foliar δ13C and δ15N values in studies based on fragmented material as markers of physiological and biochemical responses to environmental factors.

Mapping Groundwater Seepage in a Fen Using Thermal Imaging

The transport of dissolved minerals and groundwater flow plays a crucial role in the ecosystem of many wetlands. Nonetheless, installing equipment to monitor groundwater seepage is invasive, harms vegetation, and can impact biodiversity. By remotely mapping surface temperature in late summer, when there is the greatest difference between warm soil and cold groundwater, temperature patterns can expose areas with the greatest upward gradient and flow. The conventional method of using tensiometers to measure hydraulic gradient and estimate flux using Darcy’s law was applied and compared with thermal imaging to characterize groundwater seepage at two contrasting sites within a central North Dakota fen (groundwater discharge wetland). Both sites exhibited variable gradients between the shallow and deep tensiometers. The temperature trend determined from the thermal imaging showed a closer relationship to the measured hydraulic gradients at the herbaceous (Sedge) site than at the wooded (Willow) site. Saturated hydraulic conductivity K ranged from 6 × 10−5 to 2 × 10−4 m/s for the Willow site; and 6 × 10−6 to 1 × 10−4 m/s for Sedge site. The flux calculated for the Willow site ranged from 1.4 × 10−5 to 2.7 × 10−4 m/s and that of the Sedge site ranged from 2.2 × 10−6 to 6.3 × 10−5 m/s. The gradients are affected at shallow depth because of heterogeneous soil stratigraphy, which is likely the reason that seepage faces at the sites cannot be mapped solely by thermal imaging.

PORO-FSSI-FOAM model for seafloor liquefaction around a pipeline under combined random wave and current loading

In this study, unlike most previous investigations have limited to the regular wave conditions or combined wave and current conditions, a numerical model for seabed response around a pipeline in a trenched layer due to random waves is established. Three different wave spectra including the JONSWAP spectrum, Bretchneider–Mitsuyasu spectrum and Pierson–Moscowitz spectrum are considered in the present model for the simulation of random waves. Numerical examples indicate that the irregular wave-induced pore-water pressure can randomly amplify the upward gradient of the pore-water pressure in the porous seabed, making the backfill sand layer more likely to be liquefied at a deeper depth. It is observed that the upper width of the trench layer becomes larger once the seabed liquefaction occurs, which can effectively prevent the seabed liquefied surface from penetrating into the bottom of the pipeline by increasing the backfill thickness to twice of the pipe diameter. The superimposition of the irregular waves on the following current has more significant effect on the maximum-development of the seabed liquefaction depth, which is particularly obvious when the sand-bed is in the random wave system by using the JONSWAP spectrum.

Groundwater Quality Characterization in an Overallocated Semi-Arid Coastal Area Using an Integrated Approach: Case of the Essaouira Basin, Morocco

In this study, hydrogeochemical analyses were combined with geographic information system (GIS) tools to investigate salinization sources of groundwater in the downstream part of the Essaouira basin, and to analyze the spatiotemporal trends in groundwater quality. To assess groundwater suitability for drinking purposes, the quality of sampled water was compared with the World Health Organization (WHO) and the Moroccan guidelines. Wilcox and US salinity laboratory (USSL) diagrams were used to evaluate groundwater suitability for irrigation. Hydrogeochemical analyses revealed that groundwater is of Na-Cl and Ca-Mg-Cl types. The analyses of the correlation between the chemical elements showed that the water–rock interaction and the reverse ion exchange are the major processes impacting groundwater degradation in the study area. The study of groundwater suitability for drinking and irrigation purposes shows that groundwater quality in the study area is permissible, but not desirable for human consumption. Additionally, groundwater is permissible for agricultural use but with high-salinity hazards. The spatial distribution of the physicochemical elements shows a general upward gradient from the north to the south and from the east to the west. The trend in groundwater quality during the last five years shows a shifting in the quality from the mixed Ca-Mg-Cl to the Na-Cl type.

Phytohormone cytokinin guides microtubule dynamics during cell progression from proliferative to differentiated stage

Cell production and differentiation for the acquisition of specific functions are key features of living systems. The dynamic network of cellular microtubules provides the necessary platform to accommodate processes associated with the transition of cells through the individual phases of cytogenesis. Here, we show that the plant hormone cytokinin fine‐tunes the activity of the microtubular cytoskeleton during cell differentiation and counteracts microtubular rearrangements driven by the hormone auxin. The endogenous upward gradient of cytokinin activity along the longitudinal growth axis in Arabidopsis thaliana roots correlates with robust rearrangements of the microtubule cytoskeleton in epidermal cells progressing from the proliferative to the differentiation stage. Controlled increases in cytokinin activity result in premature re‐organization of the microtubule network from transversal to an oblique disposition in cells prior to their differentiation, whereas attenuated hormone perception delays cytoskeleton conversion into a configuration typical for differentiated cells. Intriguingly, cytokinin can interfere with microtubules also in animal cells, such as leukocytes, suggesting that a cytokinin‐sensitive control pathway for the microtubular cytoskeleton may be at least partially conserved between plant and animal cells.

The 1997 Mars Pathfinder Spacecraft Landing Site: Spillover Deposits from an Early Mars Inland Sea

The Martian outflow channels comprise some of the largest known channels in the Solar System. Remote-sensing investigations indicate that cataclysmic floods likely excavated the channels ~3.4 Ga. Previous studies show that, in the southern circum-Chryse region, their flooding pathways include hundreds of kilometers of channel floors with upward gradients. However, the impact of the reversed channel-floor topography on the cataclysmic floods remains uncertain. Here, we show that these channel floors occur within a vast basin, which separates the downstream reaches of numerous outflow channels from the northern plains. Consequently, floods propagating through these channels must have ponded, producing an inland sea, before reaching the northern plains as enormous spillover discharges. The resulting paleohydrological reconstruction reinterprets the 1997 Pathfinder landing site as part of a marine spillway, which connected the inland sea to a hypothesized northern plains ocean. Our flood simulation shows that the presence of the sea would have permitted the propagation of low-depth floods beyond the areas of reversed channel-floor topography. These results explain the formation at the landing site of possible fluvial features indicative of flow depths at least an order of magnitude lower than those apparent from the analyses of orbital remote-sensing observations.

Misreporting Month of Birth: Diagnosis and Implications for Research on Nutrition and Early Childhood in Developing Countries

A large literature has used children’s birthdays to identify exposure to shocks and estimate their impacts on later outcomes. Using height-for-age z scores (HAZ) for more than 990,000 children in 62 countries from 163 Demographic and Health Surveys (DHS), we show how random errors in birth dates create artifacts in HAZ that can be used to diagnose the extent of age misreporting. The most important artifact is an upward gradient in HAZ by recorded month of birth (MOB) from start to end of calendar years, resulting in a large HAZ differential between December- and January-born children of –0.32 HAZ points. We observe a second artifact associated with round ages, with a downward gradient in HAZ by recorded age in months, and then an upward step after reaching ages 2, 3, and 4. These artifacts have previously been interpreted as actual health shocks. We show that they are not related to agroclimatic conditions but are instead linked to the type of calendar used and arise mainly when enumerators do not see the child’s birth registration cards. We explain the size of the December–January gap through simulation in which 11 % of children have their birth date replaced by a random month. We find a minor impact on the average stunting rate but a larger impact in specific error-prone surveys. We further show how misreporting MOB causes attenuation bias when MOB is used for identification of shock exposure as well as systematic bias in the impact on HAZ of events that occur early or late in each calendar year.

Identifying and Understanding Communities Using Twitter to Connect About Depression: Cross-Sectional Study.

BackgroundDepression is the leading cause of diseases globally and is often characterized by a lack of social connection. With the rise of social media, it is seen that Twitter users are seeking Web-based connections for depression.ObjectiveThis study aimed to identify communities where Twitter users tweeted using the hashtag #MyDepressionLooksLike to connect about depression. Once identified, we wanted to understand which community characteristics correlated to Twitter users turning to a Web-based community to connect about depression.MethodsTweets were collected using NCapture software from May 25 to June 1, 2016 during the Mental Health Month (n=104) in the northeastern United States and Washington DC. After mapping tweets, we used a Poisson multilevel regression model to predict tweets per community (county) offset by the population and adjusted for percent female, percent population aged 15-44 years, percent white, percent below poverty, and percent single-person households. We then compared predicted versus observed counts and calculated tweeting index values (TIVs) to represent undertweeting and overtweeting. Last, we examined trends in community characteristics by TIV using Pearson correlation.ResultsWe found significant associations between tweet counts and area-level proportions of females, single-person households, and population aged 15-44 years. TIVs were lower than expected (TIV 1) in eastern, seaboard areas of the study region. There were communities tweeting as expected in the western, inland areas (TIV 2). Counties tweeting more than expected were generally scattered throughout the study region with a small cluster at the base of Maine. When examining community characteristics and overtweeting and undertweeting by county, we observed a clear upward gradient in several types of nonprofits and TIV values. However, we also observed U-shaped relationships for many community factors, suggesting that the same characteristics were correlated with both overtweeting and undertweeting.ConclusionsOur findings suggest that Web-based communities, rather than replacing physical connection, may complement or serve as proxies for offline social communities, as seen through the consistent correlations between higher levels of tweeting and abundant nonprofits. Future research could expand the spatiotemporal scope to confirm these findings.

Magnetic control of flame stability: Application to oxygen-enriched and carbon dioxide-diluted sooting flames

This present study explores possible stabilization mechanisms in flickering, sooting, ethylene flames burning in varying density coflow and exposed to different levels of an upward gradient of the square of the magnetic flux density (∇(B2)). In normal gravity, flame flickering defines a natural large scale and low frequency flame oscillation that is induced by a so called modified Kelvin–Helmholtz type instability. To assess the potential of the magnetically induced stabilization process, a range of coflow mixtures with varying N2, O2, and CO2 contents in volume is studied. As a result, a domain of controllable flame stability is identified. Its extension depends on the maximum magnitude of ∇(B2), i.e., 18.2 T2/m for the present experimental setup. Spectral emission rate, spectral absorption coefficient, soot volume fraction, and soot temperature fields are measured in the flame by the Modulated Absorption/Emission technique (MAE). In agreement with former studies, the soot content is shown to play a key role in the stabilization process. Due to the magnetic force that is mainly acting on paramagnetic oxygen molecules, opposing gravity, and generated by ∇(B2), the residence time of soot particles in the flame presumably increases with ∇(B2). With growing soot volume fraction, radiative heat losses are enhanced leading to flame cooling. Therefore, flames exposed to the magnetic field exhibit both lower density gradients through the flame sheet and a weaker field of buoyant acceleration in the hot exhaust gas stream. Both mechanisms then reduce the flame vulnerability to the onset of oscillations due to modified Kelvin–Helmholtz type instabilities. The findings may be relevant for designing strategies to control the stability of oxyfuel combustion.

Misreporting Month of Birth: Implications for Research on Nutrition and Early Childhood in Developing Countries

A large literature uses children's birthdays to identify exposure to shocks and estimate their impacts on later outcomes. Using height-for-age Z scores (HAZ) for over 990,000 children in 62 countries from 163 Demographic and Health Surveys (DHS), we show how random errors in birthdates create artifacts in HAZ that can be used to diagnose the extent of age misreporting. The most important artifact is an upward gradient in HAZ by recorded month of birth (MOB) from start to end of calendar years, resulting in a large HAZ differential between December- and January-born children of -0.32 HAZ points. We observe a second artifact associated with round ages, with a downward gradient in HAZ by recorded age in months, then an upward step after reaching ages 2, 3 and 4. These artifacts have previously been interpreted as actual health shocks. We show that they are not related to agro-climatic conditions, but are linked to the type of calendar used and arise mainly when enumerators do not see the child's birth registration cards. We explain the size of the December-January gap through simulation where 11% of children have their birthdate replaced by a random month. We find a minor impact on the average stunting rate, but a larger impact in specific error-prone surveys. We further show how misreporting MOB causes attenuation bias when MOB is used for identification of shock exposure, and also systematic bias in the impact on HAZ of events that occur early or late in each calendar year.