Intensity Variations Research Articles

Magnetic Fingerprints for the Paleoenvironmental Evolutions Since the Last Deglaciation: Evidence From the Northwestern South China Sea Sediments

AbstractRapid global changes since the last deglaciation can be well documented in marginal sea sediments, while isolating individual paleoenvironmental signals is still challenging. Here, we identified magnetic minerals and unmixed their variations in sediments from the northwestern South China Sea to decipher environmental variations since the last deglaciation. The variation in the hematite to goethite ratio indicates a relatively drier mid‐Holocene and a wetter early and late Holocene in the Red River catchment. The position shift and intensity variation of Western Pacific Subtropical High may account for the Holocene precipitation changes. A higher chemical weathering intensity accompanied by a relatively more fine‐grained magnetite input during the last deglaciation suggests decoupling of the Asian Summer Monsoon and chemical weathering in the catchment, which might have been caused by the shelf exposure during the deglaciation. In addition, the relative abundance of biogenic magnetite increased with the sea level and possible deep‐water temperature rise. Therefore, magnetic minerals such as hematite, goethite, detrital and biogenic magnetite are markedly potential fingerprints for continent‐ocean environmental changes.

Exploring the aromatic typicity of blended red wines from geographically close sub-regions in AOC Corbières: a sensory and chemical approach

Several studies have reported a terroir effect on monovarietal wines originating from geographically close areas, using both aromatic and sensory analyses. However, few studies have evaluated this effect on blended wines, a widespread practice that is recognised as adding great complexity to wines. This study aimed to discriminate blended wines produced in five sub-regions of the Corbières AOC according to their aromatic and sensory profiles and across two vintages: 2018 and 2019. The wines’ aromatic profiles were semi-quantified using HS-SPME-GC-MS, and the sensory descriptors enabling the differentiation of the wines were identified by QDA analysis. Although blending is a frequently used process adapted for the production of homogeneous wines within an appellation, the sensory and chemical profiles enabled us to differentiate wines of the Lagrasse and Lézignan sub-regions from those of the Maritime and Durban sub-regions. The variation in intensity of red fruit jam notes may be linked to terroir factors relating to the micro-climatic conditions. Wines from vineyards in coastal regions or at higher elevations were discriminated by lower intensities of this descriptor. However, other discriminating descriptors, such as amyl, earthy or cooked vegetables, could be related to the winemaking process. Correlations were found between the tendencies observed regarding the sensory markers (such as red fruit jam, butter/lactic, amylic, cooked vegetable) and those regarding the chemical families of aroma or specific aroma compounds (such as ethyl esters, higher alcohols and sulphur compounds), whose production is particularly affected by the winemaking processes. Finally, this study shows that it is possible to discriminate blended wines from different geographically close regions, and that the terroir factor with the greatest influence on this discrimination seems to be linked to winemaking processes, including the type of blending carried out.

Free secondary education policy and education attainment

This paper investigates the impact of Ghana’s Universal fee-free secondary education policy (FreeSHS) on educational attainment (completion rates). The policy was introduced in the school year 2017/2018, allowing every child to pursue secondary education irrespective of their background. We emphasize the educational outcomes of schoolgirls as they are shown to be at a greater disadvantage when accessing higher education in Ghana. Given the universality of the policy, we estimate a Difference-in-Differences model using variations in the treatment intensity across districts. The treatment and comparison groups are thus defined based on the differences in the uptake rate (changes in the uptake of education due to a price change). The paper draws from a comprehensive panel dataset capturing the demand and supply factors to education across 261 districts in Ghana. The empirical findings suggest that schoolgirls’ completion rate increased by 14 percentage points in high uptake districts, whereas the reform impact is estimated at 14.9 percentage points overall (for boys and girls). In effect, the absorption of education costs by the state serves as a critical incentive for cost-constrained households and an efficient measure for correcting market failures related to access and completion of secondary education for girls.

Variable carbon isotope fractionation of photosynthetic communities over depth in an open-ocean euphotic zone

Marine particulate organic carbon (POC) contributes to carbon export, food webs, and sediments, but uncertainties remain in its origins. Globally, variations in stable carbon isotope ratios (δ13C values) of POC between the upper and lower euphotic zones (LEZ) indicate either varying aspects of photosynthetic communities or degradative alteration of POC. During summertime in the subtropical north Atlantic Ocean, we find that δ13C values of the photosynthetic product phytol decreased by 6.3‰ and photosynthetic carbon isotope fractionation (εp) increased by 5.6‰ between the surface and the LEZ-variation as large as that found in the geologic record during major carbon cycle perturbations, but here reflecting vertical variation in δ13C values of photosynthetic communities. We find that simultaneous variations in light intensity and phytoplankton community composition over depth may be important factors not fully accounted for in common models of photosynthetic carbon isotope fractionation. Using additional isotopic and cell count data, we estimate that photosynthetic and non-photosynthetic material (heterotrophs or detritus) contribute relatively constant proportions of POC throughout the euphotic zone but are isotopically more distinct in the LEZ. As a result, the large vertical differences in εp result in significant, but smaller, differences in the δ13C values of total POC across the same depths (2.7‰). Vertical structuring of photosynthetic communities and export potential from the LEZ may vary across current and past ocean ecosystems; thus, LEZ photosynthesis may influence the exported and/or sedimentary δ13C values of both phytol and total organic carbon and affect interpretations of εp over geologic time.

Discovery of Magnetically Guided Metal Accretion onto a Polluted White Dwarf

Dynamically active planetary systems orbit a significant fraction of white dwarf stars. These stars often exhibit surface metals accreted from debris disks, which are detected through infrared excess or transiting structures. However, the full journey of a planetesimal from star-grazing orbit to final dissolution in the host star is poorly understood. Here, we report the discovery that the cool metal-polluted star WD 0816–310 has cannibalized heavy elements from a planetary body similar in size to Vesta, and where accretion and horizontal mixing processes have clearly been controlled by the stellar magnetic field. Our observations unveil periodic and synchronized variations in metal line strength and magnetic field intensity, implying a correlation between the local surface density of metals and the magnetic field structure. Specifically, the data point to a likely persistent concentration of metals near a magnetic pole. These findings demonstrate that magnetic fields may play a fundamental role in the final stages of exoplanetary bodies that are recycled into their white dwarf hosts.

Carbon emission and maintenance cost of commercial buildings: Quantification, analysis and benchmarking

Minimizing the carbon emissions of buildings entails effective resources deployment to maintain the buildings and their facilities. Through an environmental-economics lens, a mixed methods research was conducted on 27 commercial buildings, from which reliable and longitudinal data were collected. Considering the different mixes of premises (office, retail and car park) in the buildings and their variability in carbon emission intensity and maintenance cost intensity, a normalization method was developed based on appropriate scaling factors of the premises. Correlation analyses revealed significant correlations between building age and builder's work maintenance cost, as well as between building area and carbon emissions. The finding that the carbon emission intensities of the buildings decreased with capital project costs implies that capital projects, especially energy retrofits, can significantly reduce carbon emissions. Using the benchmarking charts constructed, the buildings - with or without capital projects implemented - were compared in terms of carbon emissions and maintenance costs. Besides contributing insights into future research, the study results hold significance for stakeholders, including policy makers, building owners and facilities managers, in optimizing maintenance resources to attain a cleaner built environment.

Based on neural network cascade abnormal texture information dissemination of classification of patients with schizophrenia and depression

This study used MRI brain image segmentation to identify novel magnetic resonance imaging (MRI) biomarkers to distinguish patients with schizophrenia (SCZ), major depressive disorder (MD), and healthy control (HC). Brain texture measurements, including entropy and contrast, were calculated to capture variability in adjacent MRI voxel intensity. These measures are then applied to group classification in deep learning techniques and combined with hierarchical correlations to locate results. Texture feature maps were extracted from segmented brain MRI scans of 141 patients with schizophrenia (SCZ), 103 patients with major depressive disorder (MD) and 238 healthy controls (HC). Gray scale coassociation matrix (GLCM) is a monomer matrix calculated in a voxel cube. Deep learning methods were evaluated to determine the application capability of texture feature mapping in binary classification (SCZ vs. HC, MD vs. HC, SCZ vs. MD). The method is implemented by repeated nesting and cross-validation for feature selection. Regions that show the highest correlation (positive or negative). In this study, the authors successfully classified SCZ, MD and HC. This suggests that texture analysis can be used as an effective feature extraction method to distinguish different disease states. Compared with other methods, texture analysis can capture richer image information and improve classification accuracy in some cases. The classification accuracy of SCZ and HC, MD and HC, SCZ and MD reached 84.6%, 86.4% and 76.21%, respectively. Among them, SCZ and HC are the most significant features with high sensitivity and specificity.

A self-adjusting method to generate daily consistent nighttime light data for the detection of short-term rapid human activities

Nighttime light (NTL) has become an emerging indicator of the magnitude and changes in human settlement and activities. A recently released Lunar-BRDF-corrected NTL product, Black Marble VNP46A2, with enhanced temporal (daily) and spatial (15 arc-second) resolutions, has the potential to monitor human reactions to short-term events with rapid light intensity variations. However, the VNP46A2 NTL exhibits unexpected large daily variations resulting from two residual errors (spatial observational coverage mismatch and angular effect), leading to difficulty in extracting true change signals of NTL time series. In this study, we developed a Self-adjusting method featuring Filter and Angular effect Correction (SFAC) to eliminate the two errors without any auxiliary data. The proposed adjusted-average filtering effectively reduced the mismatch error and enhanced data consistency with less “blooming effect” than other filtering methods. The normalized standard deviation of daily NTL was largely reduced in the selected airport areas after filtering. The variation caused by the angular effect has also been corrected by a relative calibration method using the 16 days' cycle of satellite view angles, which apparently decreases the dependence of the light intensity on the view angles. We further explored and found that the detectability of short-term rapid events (i.e., festival/event celebration with increased NTL and power outage with reduced NTL) using SFAC-corrected VNP46A2 outperformed the original product. More detailed information on rapid events and evolutions in small spaces is expected to be digested with the high-quality, SFAC-corrected daily consistent VNP46A2 NTL data.

Defect regulation of a distinctive synthetic Eu2+-doped SiAlON S-phase towards controllable spectra and thermal quenching for white-light-emitting diode

Targeted control of the luminescent properties of phosphors for white-light-emitting diode (WLED) applications, particularly spectral position and thermal stability, is crucial. In this study, a newly developed Eu2+-doped sialon S-phase BaAl1+ySi5-yO2-y/2N7 with intrinsic O vacancy (Vo) defects was synthesised using a special raw material ratio with an O deficiency. A series of structure–performance characterisations and density functional theory (DFT) calculations were performed. It was found that the spectral position and thermal stability of the samples could be realised by defect regulation using two approaches: regulation of the Eu2+ content and Al/Si ratio. Consequently, the emitting colour of the samples could be adjusted from green to yellow, leading to a lower colour temperature and higher colour rendering in the assembled WLED. The abnormal thermal quenching effect can also be suppressed with less variation in the emission intensity and colour purity at high temperatures. The defect regulation process investigated in this study will hopefully offer novel ideas for improving the luminescence properties of phosphors for extensive WLED applications.

Volatile organic compounds in the habitat of the escamolera ant (Liometopum apiculatum Mayr) in Zacatecas, Mexico

Volatile organic compounds (VOCs) take part in the biological processes of insects; however, these compounds have not been determined for genus Liometopum. The objective of this study was to identify the variability of the VOCs found in the Liometopum apiculatum habitat during the exploitation season. During the 2017 preseason and season, 35 air samples were collected from the nests of five L. apiculatum colonies established in crassicaule scrub vegetation; additionally, another 35 samples were taken from their foraging sites. Using a gas chromatograph with an electronic nose detector, the VOCs were identified with the Kovats index. In addition, a principal component analysis (PCA) was carried out to evaluate the intensity variability per season. Fourty-eight VOCs were identified in the L. apiculatum habitat. The most significant VOCs included: saturated hydrocarbon (17%), aldehydes (17%), alcohols (15%), and esters (10%). PCA accounted for 79.5% (PC1=53.8 and PC2=25.7) of the intensity variability of the VOCs in the habitat between seasons. The escamol season was characterized by the 3-methyl-3-sulfonyl butan-1-ol, 2-Methylbutanoic acid, and trimethylamine. This profile of the VOCs in the L. apiculatum habitat is a pioneer work and has future implications for the conservation and sustainable exploitation of the escamolera ant.

Cash for Coolers or Sustainable Lighting? Assessing Different Components of a Large-Scale Energy Efficiency Program in Mexico

In one of the largest demand-side energy efficiency programs at the time, the Mexican government supported more than 11 million, mostly low-income households in replacing their old light bulbs and appliances with more efficient models. Previous evaluations of this program focused exclusively on appliances, which made up almost 90 per cent of the total program cost, and found modest benefits in terms of energy savings. This study compares the respective effects of replacing light bulbs and appliances simultaneously in a single econometric framework, using data from nationally representative household surveys and a difference-in-differences approach which exploits geographical variation in treatment intensities. Despite using different sources and types of data, our results for the appliances replacement intervention are largely in line with the estimates of previous studies. In addition, we find that the impact on energy consumption (proxied by the amount paid for electricity) of replacing light bulbs was of comparable magnitude as that of replacing appliances, although the average cost per participating household was much smaller. Overall, our results suggest that low-cost investments that help poor households reduce their energy consumption for lighting can have high returns on energy efficiency in the residential sector.

An analysis of real-time suicidal ideation and its relationship with retrospective reports among young people with borderline personality disorder.

This study aimed to analyze the real-time variability of suicidal ideation intensity and the relationship between real-time and retrospective reports of suicidal ideation made on the Beck Scale for Suicidal Ideation (BSS), among young people with borderline personality disorder (BPD). Young people (15-25-year olds) with BPD (N = 46), recruited from two government-funded mental health services, rated the intensity of their suicidal ideation six times per day for 7 days before completing the BSS. For 70% of participants, suicidal ideation changed in intensity approximately five times across the week, both within and between days. BSS ratings were most highly correlated with the highest real-time ratings of suicidal ideation. However, this was not significantly different from the relationship between the BSS and both the average and most recent ratings. Median ratings of suicidal ideation intensity were higher on the BSS compared with an equivalent question asked in real time. Findings suggest that young people with BPD experience high levels of fluctuation in their intensity of suicidal ideation across a week and that retrospective reports of suicidal ideation might be more reflective of the most intense experience of suicidal ideation across the week.

Cooling-excited infrared thermography for enhancing the detection of concrete filled steel tube interfacial debonding at concrete hydration

Interfacial Debonding occurring in concrete-filled steel Tube (CFST) arch bridges during construction is a critical issue, which can reduce the CFST carrying capacity and thus degrade the operational lifespan of the bridge. Timely detection of this type of defect during bridge construction can be highly cost-effective but rare sensing technology was reported for detection at this stage. Infrared thermography has been recognized as a potential detection method but still faces the challenge of low thermal contrast developed from concrete hydration. This research investigates the feasibility of using hydration heat as an internal heat source and proposes water-spray cooling as an external excitation to improve infrared debonding detection. The experimental study is carried out to investigate the detectability enhancement before and after the cooling excitation in terms of different debonding sizes and thicknesses. An image enhancement method is then proposed for debonding visualization based on the temperature difference matrix. In addition, the numerical simulation is conducted to analyze the cooling effect regarding the excitation intensity variation. The findings reveal that the thermal contrast of debonding ranges from 0.1 to 0.35℃ before cooling excitation and is enhanced by 2–3 times thereafter. In addition, the developed maximum thermal contrast of debonding can be characterized through a linear relationship to the cooling excitation intensity based on numerical analysis. The proposed method shows significant feasibility for early detection of debonding in CFST during arch bridge construction, which enables a new potential for structural inspection.

Seedling Growth Stress Quantification Based on Environmental Factors Using Sensor Fusion and Image Processing

Understanding the diverse environmental influences on seedling growth is critical for maximizing yields. The need for a more comprehensive understanding of how various environmental factors affect seedling growth is required. Integrating sensor data and image processing techniques offers a promising approach to accurately detect stress symptoms and uncover hidden patterns, enhancing the comprehension of seedling responses to environmental factors. The objective of this study was to quantify environmental stress symptoms for six seedling varieties using image-extracted feature characteristics. Three sensors were used: an RGB camera for color, shape, and size information; a thermal camera for measuring canopy temperature; and a depth camera for providing seedling height from the image-extracted features. Six seedling varieties were grown under controlled conditions, with variations in temperature, light intensity, nutrients, and water supply, while daily automated imaging was conducted for two weeks. Key seedling features, including leaf area, leaf color, seedling height, and canopy temperature, were derived through image processing techniques. These features were then employed to quantify stress symptoms for each seedling type. The analysis of stress effects on the six seedling varieties revealed distinct responses to environmental stressors. Integration of color, size, and shape parameters established a visual hierarchy: pepper and pak choi seedlings showed a good response, cucumber seedlings showed a milder response, and lettuce and tomato seedlings displayed an intermediate response. Pepper and tomato seedlings exhibited a wide range of growth stress symptoms, at 13.00% to 83.33% and 2.96% to 70.01%, respectively, indicating considerable variability in their reactions to environmental stressors. The suggested classification approach provides valuable groundwork for advancing stress monitoring and enabling growers to optimize environmental conditions.

Sub-daily scale variations and trends in southwest monsoon rainfall over the West coasts of India and Myanmar

The West Coast of India (WCI) and the West Coast of Myanmar (WCM) receive a good amount of monsoon rainfall due to the orographic lifting and moisture transport from the neighbouring sea. Here, diurnal variation in rainfall amount, frequency, intensity, and contribution during the summer monsoon period was studied using TRMM 3 hourly precipitation data. The analysis was carried out over lowland, midland and highland regions of both the coasts. The subregions exhibit a similar diurnal pattern even though the intensity and frequency of rainfall vary from region to region. Generally, bimodal variations with late afternoon and early morning peaks are found over lowland and midland regions of both WCI and WCM in rainfall frequency, amount and contribution. However, highland regions exhibit unimodal variation with a single late afternoon peak. Over WCI, lowland regions exhibit primary peak during early morning, whereas lowlands of WCM exhibit primary peak during afternoon hours. Rainfall intensity exhibits a different pattern compared to other parameters. Rainfall intensity increases from south to north over both the coasts. Among the subregions, maximum rainfall intensity is found over midlands and minimum over highlands. In general, more rainfall is observed over subregions of WCM than subregions of WCI. Most of the lowland and midland regions, exhibit a significant increasing trend in rainfall frequency and contribution at morning hours and a significant decreasing trend at afternoon hours. Rainfall frequency exhibit different periodicities during different time indicating interannual heterogeneity in rainfall. The diurnal pattern of summer monsoon rainfall over the Indian and Myanmar West coasts shows remarkable latitudinal and topographical variations.

Changes in social norms during the early stages of the COVID-19 pandemic across 43 countries

The emergence of COVID-19 dramatically changed social behavior across societies and contexts. Here we study whether social norms also changed. Specifically, we study this question for cultural tightness (the degree to which societies generally have strong norms), specific social norms (e.g. stealing, hand washing), and norms about enforcement, using survey data from 30,431 respondents in 43 countries recorded before and in the early stages following the emergence of COVID-19. Using variation in disease intensity, we shed light on the mechanisms predicting changes in social norm measures. We find evidence that, after the emergence of the COVID-19 pandemic, hand washing norms increased while tightness and punishing frequency slightly decreased but observe no evidence for a robust change in most other norms. Thus, at least in the short term, our findings suggest that cultures are largely stable to pandemic threats except in those norms, hand washing in this case, that are perceived to be directly relevant to dealing with the collective threat.

Probing cell metabolism using the two-photon excitation autofluorescence lifetime of tryptophan.

Compared to intensity detection, fluorescence lifetime has the advantage of being unaffected by variations in excitation intensity, fluorophore concentration, or attenuation due to biological absorption and scattering. In this Letter, to the best of our knowledge, we present the use of the two-photon excitation autofluorescence lifetime imaging of tryptophan (TRP) to probe cell metabolism for the first time. Tests of pure chemical samples showed that the fluorescence lifetime of TRP was highly sensitive to changes in molecular conformation and the environment. In in vitro cell experiments, we successfully utilized the fluorescence lifetime of TRP to distinguish tumor cells from healthy cells, track the therapeutic effect of the tumor immunotherapy drug 1-MT for HeLa cells, and monitor cells in response to carbonyl cyanide 3-chlorophenylhydrazone (CCCP)-induced cell apoptosis. These results reveal that the two-photon excitation autofluorescence lifetime of TRP could be a sensitive natural probe of cell metabolism in living cells.

Assessment of the Spatiotemporal Variability of Urban Heat Island Intensity in Colombo Metropolitan Area


 
 
 During the last few decades, the Colombo Metropolitan Area (CMA) has experienced rapid population growth and unplanned urbanization, resulting in the replacement of natural landcover with more impervious surfaces. The primary approach of current study was to determine the gradients of air temperature and assess the spatiotemporal variation of atmospheric urban heat island (AUHI) intensity in the CMA considering a range of rural sites extending in different radial directions from the urban center. A total of sixteen rural observation sites that extend from an urban center in four directions were selected within the CMA, with four sites 3.5 km apart from each other in any direction. The air temperatures at each site were measured using HOBO UX-100-003 temperature data loggers for an 8-day period from 21st to 28th, of February 2022. The normalized difference vegetation index (NDVI) and normalized difference building index (NDBI) were used to determine the influence of land use/land cover on air temperatures. The results revealed that air temperature had a strong positive correlation with NDBI. Thus, the current study suggests that the impervious surface/s is a significant predictor of air temperature over the study area. The higher air temperatures were observed at the urban center in relation to the selected suburban and rural observation sites. Hence, the current study confirms that AUHI exists within the selected study area over the CMA. It was found that AUHI tends to be present throughout the day in the CMA. However, it becomes strong between 12.00 A.M. and 6.00 A.M and mostly weakens in the late afternoon hours. Furthermore, this study found that the timing and magnitudes of AUHI vary from direction to direction across the study area depending on the site-specific characteristics of the rural observation sites. The current study emphasizes that site-specific land use/land cover characteristics can have a significant impact on the interpretation of UHI study results even within a single metropolitan area. Therefore, taking only one rural site might not be effective in determining the UHI intensity and a range of sites need to be considered (to select from) for in-depth analysis of UHI in any given area. The findings of the current study will provide firsthand knowledge for urban planners to identify future trends in UHI in the CMA and will promote further UHI research in this area.
 Keywords: Rural observation site, Atmospheric urban heat island, Normalized Difference Vegetation Index
 
 

Non‐Destructive Tomographic Nanoscale Imaging of Ferroelectric Domain Walls

AbstractExtraordinary physical properties arise at polar interfaces in oxide materials, including the emergence of 2D electron gases, sheet‐superconductivity, and multiferroicity. A special type of polar interface is ferroelectric domain walls, where electronic reconstruction phenomena can be driven by bound charges. Great progress has been achieved in the characterization of such domain walls and, over the last decade, their potential for next‐generation nanotechnology has become clear. Established tomography techniques, however, are either destructive or offer insufficient spatial resolution, creating a pressing demand for 3D imaging compatible with future fabrication processes. Here, non‐destructive tomographic imaging of ferroelectric domain walls is demonstrated using secondary electrons. Utilizing conventional scanning electron microscopy (SEM), the position, orientation, and charge state of hidden domain walls are reconstructed at distances up to several hundreds of nanometers away from the surface. A mathematical model is derived that links the SEM intensity variations at the surface to the local domain wall properties, enabling non‐destructive tomography with good noise tolerance on the timescale of seconds. The SEM‐based approach facilitates high‐throughput screening of materials with functional domain walls and domain‐wall‐based devices, which is essential for monitoring during the production of device architectures and quality control in real‐time.

Acoustic and Spectral Analysis of Adi Triphthongs

Adi, a zero-resource indigenous tribal language of Arunachal Pradesh, originated in Tibeto-Burman. According to the “UNESCO Atlas of the World's Languages in Danger of 2017” report, Adi is critically endangered. In this research, two new Adi triphthongs, /uai/ [uai] and /oai/ [ɔai], are proposed in the phoneme set of the Adi language. Adi has 51 phonemes, including 14 monophthongs (7 short and 7 long vowels), 19 diphthongs, two triphthongs, and 16 consonants. This research analysed Adi triphthongs’ spectral and acoustic properties, including intensity variation, long-term average spectrum (LTAS), and formant distribution. The mean of the first four formant frequencies of male and female Adi speakers is measured, which may be the identification of these two phones in the Adi speech recognition systems. Four different Adi words for each triphthong are recorded from 68 individual native Adi speakers (32 males and 36 females) in Arunachal Pradesh. This study may be helpful for phonetic modelling to build speech recognition applications for the Adi language.