Intensity Maps Research Articles

Multi-scenario simulation and evaluation of the impacts of land use change on ecosystem service values in the Chishui River Basin of Guizhou Province, China

Changes in land-use patterns are the main driving factors of ecosystem service values (ESVs). The quantitative evaluation of ESVs is significant for the sustainable development of ecologically fragile areas. In this study, the Chishui River Basin (CRB) in China was selected as the study region, and an intensity map (IM) was used to analyze the transformation of land use/land cover (LULC). The modified equivalent coefficient value method was used to evaluate the ESVs based on the 2000, 2010, and 2020 land use datasets. The spatial and temporal distributions of ESV and its response to changes in LULC were analyzed using the Getis-Ord Gi* statistical method and Spearman’s rank correlation analysis. Moreover, spatial and temporal changes in LULC and ESV over the next 30 years in the four development scenarios were simulated using the Markov-PLUS model. The following results were obtained: 1) The farmland and forestland were the dominant LULC categories, and that the LULC pattern dramatically changed in the study area; 2) the total ESV of the CRB decreased significantly from 23.21 billion yuan in 2000 to 22.29 billion yuan in 2020; and 3) the ecological conservation scenario significantly promoted the total ESV, and the town development scenario was more conducive to the urbanization process. Therefore, although the ESV of the CRB showed a decreasing to slowly increasing trend in the context of a series of ecological restoration measures, scientific ecological protection and development policies must be continuously implemented to achieve harmony between ecological service improvement and urbanization development. Our results provide important information for making land-use decisions and facilitating sustainable development in ecologically protected basins.

Atomic hydrogen shows its true colours: correlations between H i and galaxy colour in simulations

ABSTRACT Intensity mapping experiments are beginning to measure the spatial distribution of neutral atomic hydrogen H i to constrain cosmological parameters and the large-scale distribution of matter. However, models of the behaviour of H i as a tracer of matter are complicated by galaxy evolution. In this work, we examine the clustering of H i in relation to galaxy colour, stellar mass, and H i mass in IllustrisTNG at z = 0, 0.5, and 1. We compare the H i-red and H i-blue galaxy cross-power spectra, finding that H i-red has an amplitude 1.5 times greater than H i-blue at large scales. The cross-power spectra intersect at ≈3 Mpc in real space and ≈10 Mpc in redshift space, consistent with z ≈ 0 observations. We show that H i clustering increases with galaxy H i mass and depends weakly on detection limits in the range MH i ≤ 108 M⊙. In terms of M⋆, we find massive blue galaxies cluster more than less massive ones. Massive red galaxies, however, cluster the weakest amongst red galaxies. These opposing trends arise from central-satellite compositions. Despite these M⋆ trends, we find that the cross-power spectra are largely insensitive to detection limits in galaxy surveys. Counter-intuitively, all auto and cross-power spectra for red and blue galaxies and H i decrease with time at all scales. We demonstrate that processes associated with quenching contribute to this trend. The complex interplay between H i and galaxies underscores the importance of understanding baryonic effects when interpreting the large-scale clustering of H i, blue, and red galaxies at z ≤ 1.

Correlative Micro‐Photoluminescence Study on Hybrid Quantum‐Well InGaN Red Light‐Emitting Diodes

To investigate nonradiative recombination processes in indium gallium nitride (InGaN)‐based red light‐emitting diodes (LEDs), an InGaN‐based red LED with a hybrid quantum well (QW) structure consisting of red and blue single quantum wells (SQWs) is characterized by micro‐photoluminescence (μ‐PL) spectroscopy. The μ‐PL mapping of the red emission reveals numerous dark spots with various sizes and contrasts. Not only the red and blue (from a blue SQW) but green emission bands are observed at some red dark spots, suggesting that indium (In) segregation is one of the causes of nonradiative recombination in the red emission. Comparing the blue and green emission images to the red emission image reveals that the dark spots in the intensity map of the red emission can be classified into four types. Through this correlative analysis, the red dark spots associated with the dark areas in the intensity map of the blue emission are attributed to the major nonradiative recombination centers in the red emission.

Hydrometeorological Disaster Mitigation Through Rainfall Intensity Mapping Using IDF in Sumatera Island, Indonesia

Hydrometeorological Disaster Mitigation Through Rainfall Intensity Mapping Using IDF in Sumatera Island, Indonesia

High-cadence Timing of Binary Pulsars with CHIME

We performed near-daily observations of the binary pulsars PSR J0218+4232, PSR J1518+4904, and PSR J2023+2853 with the Canadian Hydrogen Intensity Mapping Experiment (CHIME). For the first time, we detected the Shapiro time delay in all three pulsar binary systems, using only 2–4 yr of CHIME/Pulsar timing data. We measured the pulsar masses to be 1.49−0.20+0.23 M ⊙, 1.470−0.034+0.030 M ⊙, and 1.50−0.38+0.49 M ⊙, respectively. The companion mass to PSR J0218+4232 was found to be 0.179−0.016+0.018 M ⊙. We constrained the mass of the neutron star companion of PSR J1518+4904 to be 1.248−0.029+0.035 M ⊙, using the observed apsidal motion as a constraint on the mass estimation. The binary companion to PSR J2023+2853 was found to have a mass of 0.93−0.14+0.17 M ⊙; in the context of the near-circular orbit, this mass estimate suggests that the companion to PSR J2023+2853 is likely a high-mass white dwarf. By comparing the timing model obtained for PSR J0218+4232 with previous observations, we found a significant change in the observed orbital period of the system of Pḃ=0.14(2)×10−12 ; we determined that this variation arises from “Shklovskii acceleration” due to the relative motion of the binary system, and used this measurement to estimate a distance of d = (6.7 ± 1.0) kpc to PSR J0218+4232. This work demonstrates the capability of high-cadence observations, enabled by the CHIME/Pulsar system, to detect and refine general-relativistic effects of binary pulsars over short observing timescales.

Seasonal forecasting of Bactrocera dorsalis Hendel, 1912 (Diptera: Tephritidae) in bioclimatic zones of Sri Lanka using the SARIMA model

Bactrocera dorsalis Hendel is a severe fruit pest that causes significant economic losses globally. Despite B. dorsalis having been distributed mostly across Asia, studies on its current and future density variation in Sri Lanka are sparse to date. The present study was thus carried out to assess the contemporary density variation (2020–2022) and future density fluctuation (2023–2025) of B. dorsalis in bioclimatic zones of Sri Lanka. The density was assessed using the monthly-based fruit fly trap collection method from randomly selected 40 locations in all bioclimatic zones (wet, intermediate, dry, and arid). The SARIMA modelling technique was applied for delineating the best-fit model and for density forecasting in each bioclimatic zone. The density variations were depicted for the year and for the bioclimatic zone (2020–2025) by colour intensity maps using QGIS. According to the findings, B. dorsalis shows a seasonal component to its year-round density variation and an ascending trend in its density from 2020 to 2025. Density forecasting records a 20%, 30%, 26%, and 37% density increase in the wet, intermediate, dry, and arid zones, respectively, in 2025. In 2025, the highest predicted B. dorsalis density from the arid zone and the lowest predicted density from the wet zone were recorded. This study contains the first forecasting attempt for B. dorsalis density using the SARIMA approach as well as the application of colour-intensity depiction for its density variation in Sri Lanka, which leads decision makers and stakeholders in economic agriculture to plan the scientific management of B. dorsalis to avoid its current and potential future threat to the country’s fruit industry.

Impact of astrophysical effects on the dark matter mass constraint with 21 cm intensity mapping

ABSTRACT We present an innovative approach to constraining the non-cold dark matter model using a convolutional neural network (CNN). We perform a suite of hydrodynamic simulations with varying dark matter particle masses and generate mock 21 cm radio intensity maps to trace the dark matter distribution at z = 3 in the postreionization epoch. Our proposed method complements the traditional power-spectrum analysis. We compare the results of the CNN classification between the mock maps with different dark matter masses with those from the two-dimensional power spectrum of the differential brightness temperature map of 21 cm radiation. We find that the CNN outperforms the power spectrum. Moreover, we investigate the impact of baryonic physics on the dark matter model constraint, including star formation, self-shielding of H i gas, and ultraviolet background model. We find that these effects may introduce some contamination in the dark matter constraint, but they are insignificant compared to the system noise of the SKA instruments.

Reconstruction of Cosmological Initial Density Field with Observations from the Epoch of Reionization

The initial density distribution provides a basis for understanding the complete evolution of cosmological density fluctuations. While reconstruction in our local Universe exploits the observations of galaxy surveys with large volumes, observations of high-redshift galaxies are performed with a small field of view and therefore can hardly be used for reconstruction. Here, we propose reconstructing the initial density field using the H i 21 cm and CO line intensity maps from the epoch of reionization. Observations of these two intensity maps provide complementary information on the density field—the H i 21 cm field is a proxy of matter distributions in the neutral regions, while the CO line intensity maps are sensitive to the high-density, star-forming regions that host the sources for reionization. Technically, we employ the conjugate gradient method and develop the machinery for minimizing the cost function for the intensity mapping observations. Analytical expressions for the gradient of cost function are derived explicitly. We show that the resimulated intensity maps match the input maps of mock observations using semi-numerical simulations of reionization with an rms error ≲7% at all stages of reionization. This reconstruction is also robust with an rms error of ∼10% when an optimistic level of shot noise is applied to the CO map or white noise at the level of ≲10% of the standard deviation is applied to each map. Our proof-of-concept work demonstrates the robustness of the reconstruction method, thereby providing an effective technique for reconstructing the cosmological initial density distribution from high-redshift observations.

Modeling of TeV Galactic Cosmic-ray Anisotropy based on Intensity Mapping in an MHD Model Heliosphere

Cosmic rays do not arrive at the Earth uniformly. Recent experiments have consistently observed small anisotropies with amplitudes of ∼0.2% in the arrival directions of cosmic rays at TeV energies. We perform the modeling of the cosmic-ray anisotropy at TeV energies using the intensity-mapping method based on Liouville’s theorem. This work indicates unrealistically small-scale ansiotropies with <∼10° angular scales in the distribution of the cosmic-ray relative intensity at the outer boundary of the heliosphere. We would possibly need to resolve an issue that the experimental data covers ten years while the Magnetohydrodynamics (MHD) model heliosphere used in this work is only a single snapshot at a certain moment. Performing the intensity-mapping for multiple snapshots of the MHD model heliosphere and taking the average of the results would improve the results of this work.

An Edge Cloud Based Coordination Platform for Multi-user AR Applications

Augmented Reality (AR) applications can reshape our society enabling novel ways of interactions and immersive experiences in many fields. However, multi-user and collaborative AR applications pose several challenges. The expected user experience requires accurate position and orientation information for each device and precise synchronization of the respective coordinate systems in real-time. Unlike mobile phones or AR glasses running on battery with constrained resource capacity, cloud and edge platforms can provide the computing power for the core functions under the hood. In this paper, we propose a novel edge cloud based platform for multi-user AR applications realizing an essential coordination service among the users. The latency critical, computation intensive Simultaneous Localization And Mapping (SLAM) function is offloaded from the device to the edge cloud infrastructure. Our solution is built on open-source SLAM libraries and the Robot Operating System (ROS). Our contribution is threefold. First, we propose an extensible, edge cloud based AR architecture. Second, we develop a proof-of-concept prototype supporting multiple devices and building on an AI-based SLAM selection component. Third, a dedicated measurement methodology is described, including energy consumption aspects as well, and the overall performance of the system is evaluated via real experiments.

An Unusual Pulse Shape Change Event in PSR J1713+0747 Observed with the Green Bank Telescope and CHIME

The millisecond pulsar J1713+0747 underwent a sudden and significant pulse shape change between 2021 April 16 and 17 (MJDs 59320 and 59321). Subsequently, the pulse shape gradually recovered over the course of several months. We report the results of continued multifrequency radio observations of the pulsar made using the Canadian Hydrogen Intensity Mapping Experiment and the 100 m Green Bank Telescope in a 3 yr period encompassing the shape change event, between 2020 February and 2023 February. As of 2023 February, the pulse shape had returned to a state similar to that seen before the event, but with measurable changes remaining. The amplitude of the shape change and the accompanying time-of-arrival residuals display a strong nonmonotonic dependence on radio frequency, demonstrating that the event is neither a glitch (the effects of which should be independent of radio frequency, ν) nor a change in dispersion measure alone (which would produce a delay proportional to ν −2). However, it does bear some resemblance to the two previous “chromatic timing events” observed in J1713+0747, as well as to a similar event observed in PSR J1643−1224 in 2015.

Modeling the Morphology of Fast Radio Bursts and Radio Pulsars with fitburst

We present a framework for modeling astrophysical pulses from radio pulsars and fast radio bursts (FRBs). This framework, called fitburst, generates synthetic representations of dynamic spectra that are functions of several physical and heuristic parameters; the heuristic parameters can nonetheless accommodate a vast range of distributions in spectral energy. fitburst is designed to optimize the modeling of features induced by effects that are intrinsic and extrinsic to the emission mechanism, including the magnitude and frequency dependence of pulse dispersion and scatter broadening. fitburst removes intrachannel smearing through two-dimensional upsampling, and can account for phase-wrapping of “folded” signals that are typically acquired during pulsar-timing observations. We demonstrate the effectiveness of fitburst in modeling data containing pulsars and FRBs observed with the Canadian Hydrogen Intensity Mapping Experiment telescope.

Rethinking children’s rights in relation to planetary rights: A relational perspective in the era of climate change and other crises

This article delves into the intricate relationship between children’s rights and the broader landscape of human and more-than-human rights in times of planetary pluri-crises. While acknowledging the historical significance of the United Nation adoption of the Convention on the Rights of the Child (UNCRC) as a late 20th-century milestone, this contribution challenges the notion of treating children’s rights as a distinct right’s issue within the global context of ecological, social, economic and political turmoil. The article identifies three intensities around children’s rights within the ‘rights’ discourse to argue that ‘rights’ are always relational. Using a relational mapping informed approach to analysis, a series of three intensities is presented: a hierarchy of ‘rights’, doing ‘rights’ in the Anthropocene and thinking ‘rights’ in the context of pluri-crisis education. These intensities play across scales at local and planetary levels and highlight the urgency of reimagining children’s rights as relational with planetary rights. The article concludes with an imagined place-based scenario that explores how this mapping of intensities makes visible relational rights for early childhood education in times of climate crises in Australia, and beyond.

Characterization of Orbital Angular Momentum Beams by Polar Mapping and Fourier Transform

The recognition, decoding and tracking of vortex patterns is of increasing importance in many fields, ranging from the astronomical observations of distant galaxies to turbulence phenomena in liquids or gases. Currently, coherent light beams with orbital angular momentum (OAM) are of particular interest for optical communication, metrology, micro-machining or particle manipulation. One common task is to identify characteristic spiral patterns in pixelated intensity maps at real-world signal-to-noise ratios. A recently introduced combination of polar mapping and Fast Fourier Transform (FFT) was extended to novel sampling configurations and applied to the quantitative analysis of the spiral interference patterns of OAM beams. It is demonstrated that specific information on topological parameters in non-uniform arrays of OAM beams can be obtained from significantly distorted and noisy intensity maps by extracting one- or two-dimensional angular frequency spectra from single or concatenated circular cuts in either spatially fixed or scanning mode. The method also enables the evaluation of the quality of beam shaping and optical transmission. Results of proof-of-principle experiments are presented, resolution limits are discussed, and the potential for applications is addressed.

A serendipitous discovery of H i-rich galaxy groups with MeerKAT

ABSTRACT We report on the serendipitous discovery of 49 H i-rich galaxies in a 2.3 h Open Time observation with MeerKAT. We present their properties including their H i masses, intensity and velocity maps, and spectra. We determine that at least three H i-rich galaxy groups have been detected, potentially as part of a supergroup. Some members of these galaxy groups show clear interaction with each other in their H i emission. We cross-match the detections with PanSTARRS, Wide-field Infrared Survey Explorer, and Galaxy Evolution Explorer, and obtain stellar masses and star formation rates. One source is found to be a potential OH megamaser, but further follow-up is required to confidently determine this. For six sources with sufficient spatial resolution in H i, we produce rotation curves with BBarolo, generate mass models, and derive a dark matter halo mass. While the number of galaxies detected in this relatively short pointing appears to be at the high end of expectations compared to other MeerKAT observations and group H i mass function studies, this finding highlights the capability of MeerKAT for other serendipitous discoveries, and the potential for many more H i-rich galaxies to be revealed within both existing and upcoming Open Time data sets.

A Comprehensive Investigation of the Relationship between Fractures and Oil Production in a Giant Fractured Carbonate Field

This study examines the connections between various fracture indicators and production data with an example from one of the giant fields in the Middle East producing complex fractured carbonate lithologies. The field under study hosts two reservoirs with a long development and production history, including carbonates from the Asmari and Bangestan Formations. A fracture intensity map was generated based on the interpretation of image logs from 28 wells drilled within the field. Mud loss data were collected and mapped based on the geostatistical Gaussian Random Function Simulation (GRFS) algorithm. Maximum curvature maps were generated based on Asmari structural surface maps. Comparing the results shows a good agreement between the curvature map, fault distribution model, mud loss map, fracture intensity map, and productivity index. The results of image log interpretations led to the identification of four classes of open fractures, including major open fractures, medium open fractures, minor open fractures, and hairline fractures. Using the azimuth and dip data of the four fracture sets mentioned above, the fracture intensity log was generated as a continuous log for each well with available image log data. For this purpose, the fracture intensity log and a continuous fracture network (CFN) model were generated. The continuous fracture network model was used to generate a 3D discrete fracture network (DFN) for the Asmari Formation. Finally, a 3D upscaled model of fracture dip and azimuth, fracture porosity, fracture permeability, fracture length, fracture aperture, and the sigma parameter (the connectivity index between matrix and fracture) were obtained. The results of this study can illuminate the modeling of intricate reservoirs and the associated production challenges, providing insights not only during the initial production phase but also in the application of advanced oil recovery methods, such as thermal recovery.

SEISMICITY AND SEISMOTECTONIC STUDY FOR ALTUNKOPRI DAM SITE NORTH IRAQ

A seismicity and seismotectonicstudy for a dam site located on latitude (35˚:48΄ – 35˚:50΄) degree North and longitude (44˚:20΄) degree East was carried out. The surrounding area within a circular area ofradius 100 km was also included to determine the seismic activity.It is found that the area was subjected to 10 historical events prior 1900 year with an intensity ranges (V - IX) degree and the area exposed to about 163 recent earthquakes with Ms=1.1 – 5.9.The maps of epicentral locations, tectonic features and lineaments of the study area were compiled and drawn. Matching was carried out for these three maps and it is found that most of earthquake epicenters coincide with the main structural and tectonic phenomena at the dam site.ISO – intensity map for the dam site was also drawn. It is found that the dam site was located between (5 -6) degree earthquake intensity on MMI Scale

Characterization of the collagen network of human cheek skin using ultrasonic microscopy

Dermal collagen is the most abundant component of human skin and has a network structure that regulates the mechanical properties of the skin. Therefore, non-invasive characterization of the collagen network would be beneficial for the evaluation of skin conditions. The microscopic substructures of the network, which are individual bundles and fibers, have been optically investigated. However, the macroscopic structure of the collagen network has not been assessed. To evaluate the dermal collagen network, we developed two new indicators, volume filling factor (VFF) and collagen fiber texture (CFT), to analyze three-dimensional echo intensity maps of high-frequency ultrasonic microscopy. By identifying the difference in the elastic modulus components of the dermal layer of facial skin, the density and texture of the collagen network were characterized using VFF and CFT, respectively. These new indicators revealed that the density decreased and the texture became fine with facial age. This study demonstrates that ultrasonic microscopy is useful for investigating skin conditions, paving the way for diagnostic applications in dermatology and aesthetic medicine.

21 cm intensity mapping cross-correlation with galaxy surveys: Current and forecasted cosmological parameters estimation for the SKAO

ABSTRACT We present a comprehensive set of forecasts for the cross-correlation signal between 21 cm intensity mapping and galaxy redshift surveys. We focus on the data sets that will be provided by the SKAO for the 21 cm signal, DESI and Euclid for galaxy clustering. We build a likelihood which takes into account the effect of the beam for the radio observations, the Alcock–Paczynski effect, a simple parametrization of astrophysical nuisances, and fully exploit the tomographic power of such observations in the range z = 0.7–1.8 at linear and mildly non-linear scales (k &amp;lt; 0.25h Mpc−1). The forecasted constraints, obtained with Monte Carlo Markov Chains techniques in a Bayesian framework, in terms of the six base parameters of the standard ΛCDM model, are promising. The predicted signal-to-noise ratio for the cross-correlation can reach ∼50 for z ∼ 1 and k ∼ 0.1h Mpc−1. When the cross-correlation signal is combined with current Cosmic Microwave Background (CMB) data from Planck, the error bar on $\Omega _{\rm c}\, h^2$ and H0 is reduced by factors 3 and 6, respectively, compared to CMB only data, due to the measurement of matter clustering provided by the two observables. The cross-correlation signal has a constraining power that is comparable to the autocorrelation one and combining all the clustering measurements a sub-per cent error bar of 0.33 per cent on H0 can be achieved, which is about a factor 2 better than CMB only measurements. Finally, as a proof of concept, we test the full pipeline on the real data measured by the MeerKat collaboration (Cunnington et al. 2022) presenting some (weak) constraints on cosmological parameters.

Investigation of graphene-perovskite integration for enhanced absorption of solar thermal absorber for industrial heating applications

Advanced materials are critical for enhancing the efficiency of solar absorbers. Hence, the present study looks at the unique interaction between graphene and perovskite materials, a combination that has the potential to change the landscape of solar energy harvesting. The Graphene–Perovskite Integrated Solar Absorber (GPISA) structure harvests more than 98 % in UV and VIS regions ranging from 200 nm and goes up to 4000 nm of the solar spectrum using the Finite Element Method (FEM). Not only does it boast a broader absorption range from 200 to 4000 nm, covering virtually the entire solar spectrum, but it also achieves an impressive average absorption of 95.50 %. Additionally, the comprehensive analysis of its performance, encompasses optimized parameterization, exhaustive mapping of electric and magnetic field intensities, and in-depth investigation of both transverse magnetic (TM) and transverse electric (TE) field behaviors. This correlates to a weighted absorption rate of more than 97 % in the AM1.5 solar spectrum, as well as endurance to varied incoming angles (0°–80°) without considerable absorption loss, making it suitable for real-world direct sunlight absorptance. The GPISA is significantly more cost-effective due to its 3240 nm thickness. Overall, GPISA's exceptional combination of broad absorption, high efficiency, and compact design firmly positions it as a frontrunner in the advancement of efficient, high-performance solar energy harvesting. GPISA has efficient uses in solar induction systems as well as solar air, water heating, and other industrial heating applications.