Spatial Origin Research Articles

Leveraging spatial transcriptomics data to recover cell locations in single-cell RNA-seq with CeLEry

Single-cell RNA sequencing (scRNA-seq) has revolutionized our understanding of cellular heterogeneity in health and disease. However, the lack of physical relationships among dissociated cells has limited its applications. To address this issue, we present CeLEry (Cell Location recovEry), a supervised deep learning algorithm that leverages gene expression and spatial location relationships learned from spatial transcriptomics to recover the spatial origins of cells in scRNA-seq. CeLEry has an optional data augmentation procedure via a variational autoencoder, which improves the method’s robustness and allows it to overcome noise in scRNA-seq data. We show that CeLEry can infer the spatial origins of cells in scRNA-seq at multiple levels, including 2D location and spatial domain of a cell, while also providing uncertainty estimates for the recovered locations. Our comprehensive benchmarking evaluations on multiple datasets generated from brain and cancer tissues using Visium, MERSCOPE, MERFISH, and Xenium demonstrate that CeLEry can reliably recover the spatial location information for cells using scRNA-seq data.

An Evolving Spacetime Metric Induced by a ‘Static’ Source

In a series of recent papers we developed a formulation of general relativity in which spacetime and the dynamics of matter evolve with a Poincaré invariant parameter τ. In this paper, we apply the formalism to derive the metric induced by a ‘static’ event evolving uniformly along its t-axis at the spatial origin x=0. The metric is shown to vary with t and τ, as well as spatial distance r, taking its maximum value for a test particle at the retarded time τ=t−r/c. In the resulting picture, an event localized in space and time produces a metric field similarly localized, where both evolve in τ. We first derive this metric as a solution to the wave equation in linearized field theory, and discuss its limitations by studying the geodesic motion it produces for an evolving event. By then examining this solution in the 4+1 formalism, which poses an initial value problem for the metric under τ-evolution, we clarify these limitations and indicate how they may be overcome in a solution to the full nonlinear field equations.

Spatial distribution, source apportionment and potential ecological risk assessment of trace metals in surface soils in the upstream region of the Guanzhong Basin, China

The health of ecosystems and safety of agricultural products are correlated with trace metal pollutionin in the soil, which eventually affects mankind. For this research, topsoil (0–20 cm) was sampled from 51 locations in the upstream area of the Guanzhong Basin to determine the level of pollution, spatial distribution characteristics and origins of 15 trace metals (V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Y, Zr, Cd, Pb). The pollution index and potential ecological risk index were adopted for the accurate analyses of contamination degree and ecological risk that trace elements cause. The identification of potential sources of trace metals pollution was carried out using the APCS–MLR model and multivariate statistical analysis. Findings demonstrated that the most contaminated elements in the topsoil of the designated areas were Cr, Cu, Cd and Pb, and the average levels of all trace metal elements exceeded their respective local background values. However, most of the sampling points showed slight pollution, and a few demonstrated moderate and severe pollution. The southern, south–western and eastern parts in the research zone were relatively seriously contaminated, especially near Baoji City and Wugong County. Fe, Cu, Zn, Ni, Se were mainly caused by combination of agricultural and industrial production, the primary sources of Mn, Y, and Zr were the process of mining and industrial production, Cd and Pb originated mainly from traffic emission and agricultural pollution, and Cr mainly came from mining and metal smelting processes. Meanwhlie, some unknown pollution sources were also disclosed. This study has a reliable reference value for determining the source of trace metals in this region. To further determine the pollution sources of trace elements, long–term monitoring and management is necessary.

The cosmic web in Lyman-alpha emission

ABSTRACT We develop a comprehensive theoretical model for Lyman-alpha (Ly α) emission, from the scale of individual Ly α emitters (LAEs) to Ly α haloes (LAHs), Ly α blobs (LABs), and Ly α filaments (LAFs) of the diffuse cosmic web itself. To do so, we post-process the high-resolution TNG50 cosmological magnetohydrodynamical simulation with a Monte Carlo radiative transfer method to capture the resonant scattering process of Ly α photons. We build an emission model incorporating recombinations and collisions in diffuse gas, including radiative effects from nearby AGN, as well as emission sourced by stellar populations. Our treatment includes a physically motivated dust model, which we empirically calibrate to the observed LAE luminosity function. We then focus on the observability and physical origin of the z = 2 Ly α cosmic web, studying the dominant emission mechanisms and spatial origins. We find that diffuse Ly α filaments are, in fact, illuminated by photons that originate not only from the intergalactic medium itself but also from within galaxies and their gaseous haloes. In our model, this emission is primarily sourced by intermediate mass haloes (1010–1011 M⊙), principally due to collisional excitations in their circumgalactic media as well as central, young stellar populations. Observationally, we make predictions for the abundance, area, linear size, and embedded halo/emitter populations within filaments. Adopting an isophotal surface brightness threshold of 10−20 erg s−1 cm−2 arcsec−2, we predict a volume abundance of Ly α filaments of ∼10−3 cMpc−3 for lengths above 400 pkpc. Given sufficiently large survey footprints, detection of the Ly α cosmic web is within reach of modern integral field spectrographs, including MUSE, VIRUS, and KCWI.

Exploratory Data Analysis of Earthquake Moment Tensor Catalog in Japan Using Non-linear Graph-Based Dimensionality Reduction

The catalog of moment tensor solutions, which contains the information on spatial location, origin time and fault mechanism type of earthquakes, has been interpreted by researchers based on a wealth of past knowledge. However, the long-term routine analyses have led to the accumulation of a huge amount of data in the moment tensor catalog, and it is worth considering moving away from the artisanal approach. In this study, using dimensionality reduction of unsupervised machine learning, we performed exploratory data analysis of the moment tensor catalog in Japan to objectively obtain comprehensive images of seismic activity and to acquire knowledge on the spatial and temporal characteristics of the earthquake mechanism. Source parameters of the moment tensor catalog in Japan, spatial location (latitude, longitude, and focal depth) and source-mechanism diagram information were embedded in two-dimensional space via a non-linear graph-based dimensionality-reduction method, Uniform Manifold Approximation and Projection. On the embedding map, earthquakes in eastern and western Japan are distributed separately and are further embedded to reflect their characteristic fault mechanism and focal depth in each region. The similarity degree of the earthquakes can be obtained as the distance on the embedding map. This study demonstrates that the data visualization using dimensionality reduction is useful for intuitively and objectively understanding the regional characteristics of earthquake mechanisms. The embedding map can also be employed to visualize temporal changes in regional seismic activity and to perform a similarity search with a past event.

Distribution, composition and risk assessment of PAHs and PCBs in cryospheric watersheds of the eastern Tibetan Plateau

Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) are significant components of persistent organic pollutants (POPs) and pose a threat to both ecosystems and human health. To explore their spatial distribution, origins, and risk assessment, we collected 25 glacial meltwater and downstream river water samples in the eastern Tibetan Plateau (including the Qilian Mountains in the northeast) during the summer of 2022 (June–July). Our results showed that ∑PAHs and ∑PCBs were present in a wide range from ND-1380 ng/L and ND-1421 ng/L, respectively. Compared to other studies worldwide, the ∑PAHs and ∑PCBs in the Hengduan Mountains were at high levels. The PAHs and PCBs mainly consisted of low-molecular-weight homologs, including Ace, Flu, Phe, and PCB52. Phe was the primary component of PAHs. Glacial meltwater samples generally exhibited low concentration of PAHs and PCB52, whereas downstream river water samples typically showed high concentration of PAHs and PCB52. We attributed this characteristic to the influence of pollutants physicochemical properties, altitude effect, long-range transport (LRT), and local environmental conditions. In the eastern Tibetan Plateau glacier basin (especially in the Hailuogou watersheds), the concentration of PAHs and PCB52 in runoff generally increased with decreasing elevation. We believe that the primary factor affecting the concentration of PAHs and PCB52 in the region is the difference in local human activity inputs from various altitudes. The composition characteristics of PAHs and PCBs suggested that incomplete coal combustion and coking discharge mainly caused PAHs, while the combustion of coal and charcoal and the release of capacitors primarily caused PCBs. We assessed the carcinogenic risk of PAHs and PCBs in the glacier basin of the TP and found that the potential threat of PAHs was stronger than that of PCBs. Overall, this study provides new insights into the ecological security of water resources in eastern Tibetan Plateau. It is significant for controlling PAHs and PCBs emissions, assessing the ecological environment of the glacier watershed, and regional human health.

Emotional sounds in space: asymmetrical representation within early-stage auditory areas.

Evidence from behavioral studies suggests that the spatial origin of sounds may influence the perception of emotional valence. Using 7T fMRI we have investigated the impact of the categories of sound (vocalizations; non-vocalizations), emotional valence (positive, neutral, negative) and spatial origin (left, center, right) on the encoding in early-stage auditory areas and in the voice area. The combination of these different characteristics resulted in a total of 18 conditions (2 categories x 3 valences x 3 lateralizations), which were presented in a pseudo-randomized order in blocks of 11 different sounds (of the same condition) in 12 distinct runs of 6 min. In addition, two localizers, i.e., tonotopy mapping; human vocalizations, were used to define regions of interest. A three-way repeated measure ANOVA on the BOLD responses revealed bilateral significant effects and interactions in the primary auditory cortex, the lateral early-stage auditory areas, and the voice area. Positive vocalizations presented on the left side yielded greater activity in the ipsilateral and contralateral primary auditory cortex than did neutral or negative vocalizations or any other stimuli at any of the three positions. Right, but not left area L3 responded more strongly to (i) positive vocalizations presented ipsi- or contralaterally than to neutral or negative vocalizations presented at the same positions; and (ii) to neutral than positive or negative non-vocalizations presented contralaterally. Furthermore, comparison with a previous study indicates that spatial cues may render emotional valence more salient within the early-stage auditory areas.

NEXT-White results and roadmap towards a ton-scale detector

The goal of the NEXT collaboration is the sensitive search of the neutrinoless double beta decay of 136Xe at the Laboratorio Subterráneo de Canfranc. A first large-scale prototype of a high-pressure gas-Xenon electroluminescent TPC, NEXT-White, was operated from 2016 to 2021. This 4–kg radiopure detector has proven the outstanding performance of the NEXT technology in terms of the energy resolution (<1% FWHM at 2.6 MeV) and the topology-based background rejection. After measuring the relevant backgrounds and their spatial origin, the NEXT-White data collected with 136Xe-enriched and 136Xe-depleted gas have been used to perform a measurement of the two-neutrino mode of the double beta decay. A novel technique based on a direct background subtraction yields a half-life of . This result is consistent with the half-life derived from a background-model-dependent approach. Scaling the technological solutions of NEXT-White, the NEXT-100 detector is being constructed during 2022 and will start the physics data taking in 2023. Holding 100 kg of 136Xe and with a background index below 5×10−4 counts/keV/kg/year, NEXT-100 will perform the first competitive search for the neutrinoless double beta decay within the NEXT roadmap. After 3 years of data taking, a sensitivity to the half-life of 6×1025 yr at 90% C.L. will be achieved. The design for a future ton-scale detector, NEXT-HD, is being carried out in paralel. Operating with low-difussion gas mixtures and a reduced background budget, NEXT-HD will reach sensitivities above 1027 yr. A promising R&D line aims at eventually equiping the NEXT techonlogy with 136Ba-tagging capabilities, opening the doors for a truly background-free experiment.

الكنعانيون: أصولهم المكانية، وحدودهم الجغرافية، ومشهدهم الاجتماعي-السياسي خلال العصور البرونزية (3600-1200 ق.م)

This present study focuses on the inhabitants of the southern Levant (Canaan) during the Bronze Ages, based on a variety of physical archaeological evidence that has been uncovered both in the Levant itself and in neighboring lands. The aims of this study are fourfold: (1) to present the names of this region known to us from surviving written sources dated to the second and first millennia BCE, and to identify the spatial and ethnic origins of the Canaanites; (2) to identify the geographic borders which the neighboring peoples observed in relation to Canaan; (3) to present the Canaanites' social landscape and its manifestations in the emergence and ultimate prevalence of the city-state system throughout the region; and finally, (4) to demonstrate the political complexities that prevailed in the southern Levant during the Bronze Ages. This study pointed the author to two main conclusions: (a) that the Canaanites were native to the southern Levant and can be seen as a natural extension of the population that had inhabited the region during the Neolithic period, and (b) that the functional geographic borders of Canaan changed repeated over time, witnessing several expansions and contractions. The methodology implemented in this study consists of a review and analysis of the existing scholarly literature related to this subject; biblical texts, by their very nature, were not included in the study. تتناول هذه الدراسة سكان منطقة جنوبي بلاد الشام (بلاد كنعان) خلال العصور البرونزية بالبحث والتحليل، وذلك بالاعتماد على الشواهد الأثرية المادية المختلفة التي تم الكشف عنها في بلاد الشام نفسها وفي دول الجوار على حد سواء. وتهدف هذه الدراسة إلى تسليط الضوء على أربعة مواضيع رئيسة، هي: (1) تسميات هذه المنطقة، والأصول المكانية والعرقية لسكانها. (2) الرقعة الجغرافية التي ساد فيها الكنعانيون، وحدودهم الجغرافيّة مع دول الجوار. (3) طبيعة المشهد الاجتماعي الذي ساد في هذه المنطقة وما ترافق معه من الانتقال من نظام القبيلة البسيط إلى النظام المدني المعقد الذي أفرز نشوء الدويلة-المدينة. (4) تعقيدات المشهد السياسي الذي امتازت به بلاد كنعان بسبب غياب التوحيد السياسي، بالإضافة إلى أطماع دول الجوار، وخصوصاً الدولة المصريّة الحديثة. وقد توصلت هذه الدراسة إلى أن بلاد كنعان كانت ذات حدود جغرافيّة تتمدد تارة وتتقلص طوراً آخر، وأن الكنعانيين أصيلين في بلاد الشام ويشكلون امتداداً طبيعياً لسكان نفس المنطقة من العصر الحجري الحديث. وقد تم الاعتماد في كتابة هذا البحث على مراجعة الأدبيات ذات العلاقة، ولكن تم استثناء النصوص التوراتية منها

الكنعانيون: أصولهم المكانية، وحدودهم الجغرافية، ومشهدهم الاجتماعي-السياسي خلال العصور البرونزية (3600-1200 ق.م)

This present study focuses on the inhabitants of the southern Levant (Canaan) during the Bronze Ages, based on a variety of physical archaeological evidence that has been uncovered both in the Levant itself and in neighboring lands. The aims of this study are fourfold: (1) to present the names of this region known to us from surviving written sources dated to the second and first millennia BCE, and to identify the spatial and ethnic origins of the Canaanites; (2) to identify the geographic borders which the neighboring peoples observed in relation to Canaan; (3) to present the Canaanites' social landscape and its manifestations in the emergence and ultimate prevalence of the city-state system throughout the region; and finally, (4) to demonstrate the political complexities that prevailed in the southern Levant during the Bronze Ages. This study pointed the author to two main conclusions: (a) that the Canaanites were native to the southern Levant and can be seen as a natural extension of the population that had inhabited the region during the Neolithic period, and (b) that the functional geographic borders of Canaan changed repeated over time, witnessing several expansions and contractions. The methodology implemented in this study consists of a review and analysis of the existing scholarly literature related to this subject; biblical texts, by their very nature, were not included in the study. تتناول هذه الدراسة سكان منطقة جنوبي بلاد الشام (بلاد كنعان) خلال العصور البرونزية بالبحث والتحليل، وذلك بالاعتماد على الشواهد الأثرية المادية المختلفة التي تم الكشف عنها في بلاد الشام نفسها وفي دول الجوار على حد سواء. وتهدف هذه الدراسة إلى تسليط الضوء على أربعة مواضيع رئيسة، هي: (1) تسميات هذه المنطقة، والأصول المكانية والعرقية لسكانها. (2) الرقعة الجغرافية التي ساد فيها الكنعانيون، وحدودهم الجغرافيّة مع دول الجوار. (3) طبيعة المشهد الاجتماعي الذي ساد في هذه المنطقة وما ترافق معه من الانتقال من نظام القبيلة البسيط إلى النظام المدني المعقد الذي أفرز نشوء الدويلة-المدينة. (4) تعقيدات المشهد السياسي الذي امتازت به بلاد كنعان بسبب غياب التوحيد السياسي، بالإضافة إلى أطماع دول الجوار، وخصوصاً الدولة المصريّة الحديثة. وقد توصلت هذه الدراسة إلى أن بلاد كنعان كانت ذات حدود جغرافيّة تتمدد تارة وتتقلص طوراً آخر، وأن الكنعانيين أصيلين في بلاد الشام ويشكلون امتداداً طبيعياً لسكان نفس المنطقة من العصر الحجري الحديث. وقد تم الاعتماد في كتابة هذا البحث على مراجعة الأدبيات ذات العلاقة، ولكن تم استثناء النصوص التوراتية منها

Concentration prediction and spatial origin analysis of criteria air pollutants in Shanghai

Severe air pollution events still occur frequently in Shanghai. In order to predict when Shanghai air quality satisfies the National Ambient Air Quality Standards of China (NAAQSC) and identify potential source areas of criteria air pollutants for the regional joint prevention and control of air pollution, concentration data of PM2.5, PM10, SO2, NO2 and O3 were collected in 2014–2022 at fourteen monitoring sites across Shanghai and surrounding areas. A first – order rate equation with harmonic regression analysis was employed for time series analysis and concentration prediction. Decreasing concentrations were observed widely over all sites except O3 and NO2. It is very likely that the secondary NAAQSC standards for PMx, and SO2 would be met by 2025 and O3 and NO2 would likely become the critical pollutants that determine air quality level after 2025. Regional transport was predominant for PMx and SO2 pollution. A 3D – CWT multisite joint location method was developed to identify their potential source areas at different spatial resolutions. Weighting function correction was assigned via information entropy of endpoint numbers in each cell. A probabilistic parameter WIPSA was proposed to quantify and normalize the probability that grid cells are source areas in order to achieve fourteen – site joint location, and it was comparable and compatible at different spatial resolutions. Potential source areas of PM2.5 and PM10 were similar, including Henan, Shandong, Hebei and Anhui, while origin domains of SO2 mainly covered Henan and Hebei. In all seasons, air pollution that was transported to Shanghai (i.e., PMx and SO2) originated mainly from the North China Plain; the contribution of marine sources was neglectable.

Self-governing from below: Kurdish refugees on the periphery of European societies

ABSTRACT This study looks at how ordinary Kurdish refugees and asylum seekers set up self-governing formations to organise their life in border cities on the periphery of European societies. The Kurdish immigrants organise themselves into social communities that serve as autonomous social spaces in which they form and exercise self-governance, navigate through bureaucratic and structural obstacles, and regulate their cultural and social affairs. In this paper, I argue that contextual Kurdish identities and the immigrants’ capacity to respond are the fundamental components of four different models of immigrant self-governing establishments. Ideological agendas, kinship relationships, and shared spatial origins are significant contextual elements of collective identities that they use to construct three models of self-governance, whereas their responses to common concerns drive them to form a fate-based model of self-governance. Based on ethnographic field research and 76 in-depth interviews with Kurdish refugees and asylum seekers in bordering cities in Northern, Southern, and Western Europe, the article illuminates four self-governing models of ordinary Kurdish immigrants, their various patterns and identities, as well as internal dynamics. It sheds light on how these self-governing models of the marginalised Kurdish immigrants arise from below to produce and regulate social life without interference from state authorities.

Distance-controlled surface-enhanced Raman spectroscopy of nanoparticles.

Biological particles, e.g., viruses, lipid particles, and extracellular vesicles, are attracting significant research interest due to their role in biological processes and potential in practical applications, such as vaccines, diagnostics, and therapies. Their surface and interior contain many different molecules including lipids, nucleic acids, proteins, and carbohydrates. In this Letter, we show how distance-controlled surface-enhanced Raman spectroscopy (SERS) is a promising method to extract essential information from the spatial origin of the signal. This is a highly important parameter in the analysis of these biological particles. The principle of the method is demonstrated by using polystyrene (PS) beads as a biological particle model conjugated with gold nanospheres (AuNSs) functioning as distance-controlled SERS probes via biotin-streptavidin binding. By tuning the size of AuNSs, the Raman signal from the PS beads can be weakened while the signal from the biotin-streptavidin complex is enhanced.

Spatial Distribution, Contamination Assessment and Origin of Soil Heavy Metals in the Danjiangkou Reservoir, China.

Soil heavy metal contamination is crucial due to menacing food safety and mortal health. At present, with the fast advancement of urbanization and industrialization, heavy metals are increasingly released into the soil by anthropogenic activities, and the soil ecosystem contamination around the Danjiangkou Reservoir is directly associated with water quality security of the reservoir. In this paper, using 639 soil samples from the Danjiangkou Reservoir, Henan Province, China, we studied a variety of space distribution characteristics of heavy metals in soil. Geographic information system analysis (GIS), geo-accumulation index (Igeo), contamination factor (CF), principal component analysis (PCA) model, and positive matrix factorization (PMF) model were used together to recognize and quantify the distribution, contamination, and origin of heavy metals. We uncovered an exceptional variety of heavy metal concentrations among the tested soils: the mean arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), manganese (Mn), nickel (Ni), zinc (Zn), lead (Pb) and mercury (Hg) concentrations (14.54, 0.21, 18.69, 81.69, 898.42, 39.37, 79.50, 28.11, 0.04 mg/kg, respectively, in the topsoil (0-20 cm depth)), all exceed their background values. The mean Igeo value and CF values of these trace elements are both in descending order: Cd > Co > Mn > Ni > Pb > Zn > Cr > As > Hg. Cd was the highest contributor to the assessment of heavy metal pollution, with an average Igeo value over three, indicating that the study area is modestly contaminated by Cd. The PCA analysis and PMF model revealed three potential sources, including natural sources (PC1) for Cr, Co, Mn and Ni; agricultural sources (PC2) for Cd, Zn and Hg; and industrial emissions and transportation sources (PC3) for Pb. This study displays a map of heavy metal contamination in the eastern area topsoil of the Danjiangkou Reservoir, showing the most severe pollutant is Cd, which poses a threat to the water quality security of Danjiangkou Reservoir and provides a significant source identification for future contamination control.

Quantification of Intra- vs. Inter-Row Leaching of Major Plant Nutrients in Sloping Vineyard Soils

Nutrient leaching from agricultural soils presents an economic loss for farmers and can degrade the quality of the surrounding environment. Thus, leachates from 18 in situ wick lysimeters, installed at 40 cm soil depth at the vineyard hilltop, backslope, and footslope intra- and inter-row area (SUPREHILL Critical Zone Observatory, Croatia) were collected monthly over two years and analyzed for major plant nutrient ions. Our objectives were to quantify nutrient losses via leaching from the hilltop towards the backslope and to the footslope, and to compare leaching from vine plant rows (intra-row) with grassed areas between vine rows (inter-row). We found that the concentrations of nitrate, orthophosphate, and potassium were significantly higher in leachates collected at the footslope as compared to the hilltop and backslope only at intra- and not at inter-row positions, while ammonium was independent of the slope and row positions. The vineyard intra-row is identified as the probable spatial origin of nutrient leaching along the slope, thus confirming spatially different contributions of overall hillslope to major plant nutrients leaching. The experimental field scheme used in this study, which separately analyses vineyard intra- and inter-row, was confirmed to be an adequate approach for optimizing vineyard management practices.

Silver origins and spatial distribution in soils of southwestern France: A first assessment with cokriging

Ag is a rare, non-essential metal with many applications in different forms, including nanoparticles (Ag-NPs). Its release into the soil environment can represent a risk, due to the toxicity of silver. This study is based on the analysis of samples from the two sampling campaigns of the Soil Quality Measurement Network, RMQS1 and RMQS2, to establish the spatial distribution and origin of Ag in the soils of southwestern France (area of 90,293 km2). Given the progress of the second campaign (completion in 2027), we chose to do a cokriging to estimate the spatial distribution, with Pb, Cd or Cu as potential secondary variables. The results of the analyzes of the 35 samples of the RMQS2 indicate a range of Ag concentration in the soils going from 0.015 to 0.222 mg kg−1 and a median of 0.081 mg kg−1. Correlations were found between the concentrations of Ag Cd, Cu and Pb, and also between Ag concentrations and distance to Pb mines and deposits (r = 0.62). This suggests a common origin for Ag and Pb linked to historical exploitations of argentiferous galena. No link could be demonstrated between the concentration of Ag and the high density of anti-hail ground generators in the region. The analysis of the (auto-)variograms showed that Pb is the most relevant variable compared to Cd and Cu to achieve a cokriging. Thus, based on Ag concentrations from RMQS2 and Pb concentrations from RMQS1 (356 samples), a linear co-regionalization model was established and the co-kriging of Ag concentrations in soils calculated. Compared to ordinary kriging, cokriging improved the quality of the interpolation (decrease in the root mean square error).

Graded mesoderm assembly governs cell fate and morphogenesis of the early mammalian heart

Using four-dimensional whole-embryo light sheet imaging with improved and accessible computational tools, we longitudinally reconstruct early murine cardiac development at single-cell resolution. Nascent mesoderm progenitors form opposing density and motility gradients, converting the temporal birth sequence of gastrulation into a spatial anterolateral-to-posteromedial arrangement. Migrating precardiac mesoderm does not strictly preserve cellular neighbor relationships, and spatial patterns only become solidified as the cardiac crescent emerges. Progenitors undergo a mesenchymal-to-epithelial transition, with a first heart field (FHF) ridge apposing a motile juxta-cardiac field (JCF). Anchored along the ridge, the FHF epithelium rotates the JCF forward to form the initial heart tube, along with push-pull morphodynamics of the second heart field. In Mesp1 mutants that fail to make a cardiac crescent, mesoderm remains highly motile but directionally incoherent, resulting in density gradient inversion. Our practicable live embryo imaging approach defines spatial origins and behaviors of cardiac progenitors and identifies their unanticipated morphological transitions.

The Riemann problem for a generalized Burgers equation with spatially decaying sound speed. I Large‐time asymptotics

In this paper, we consider the classical Riemann problem for a generalized Burgers equation, u t + h α ( x ) u u x = u x x , $$\begin{equation*} u_t + h_{\alpha }(x) u u_x = u_{xx}, \end{equation*}$$ with a spatially dependent, nonlinear sound speed, h α ( x ) ≡ ( 1 + x 2 ) − α $h_{\alpha }(x) \equiv (1+x^2)^{-\alpha }$ with α > 0 $\alpha >0$ , which decays algebraically with increasing distance from a fixed spatial origin. When α = 0 $\alpha =0$ , this reduces to the classical Burgers equation. In this first part of a pair of papers, we focus attention on the large-time structure of the associated Riemann problem, and obtain its detailed structure, as t → ∞ $t\rightarrow \infty$ , via the method of matched asymptotic coordinate expansions (this uses the classical method of matched asymptotic expansions, with the asymptotic parameters being the independent coordinates in the evolution problem; this approach is developed in detail in the monograph of Leach and Needham, as referenced in the text), over all parameter ranges. We identify a significant bifurcation in structure at α = 1 2 $\alpha =\frac{1}{2}$ .

Time-calibrated phylogenies reveal mediterranean and pre-mediterranean origin of the thermophilous vegetation of the Canary Islands.

The Canary Islands have strong floristic affinities with the Mediterranean Basin. One of the most characteristic and diverse vegetation belts of the archipelago is the thermophilous woodland (between 200 and 900 m.a.s.l.). This thermophilous plant community consists of many non-endemic species shared with the Mediterranean Floristic Region together with Canarian endemic species. Consequently, phytogeographic studies have historically proposed the hypothesis of an origin of the Canarian thermophilous species following the establishment of the summer-dry mediterranean climate in the Mediterranean Basin around 2.8 million years ago. Time-calibrated phylogenies for 39 plant groups including Canarian thermophilous species were primarily analysed to infer colonization times. In particular, we used 26 previously published phylogenies together with 13 new time-calibrated phylogenies (including newly generated plastid and nuclear DNA sequence data) to assess whether the time interval between stem and crown ages of Canarian thermophilous lineages postdates 2.8 Ma. For lineages postdating this time threshold, we additionally conducted ancestral area reconstructions to infer the potential source area for colonization. A total of 43 Canarian thermophilous lineages were identified from 39 plant groups. Both mediterranean (16) and pre-mediterranean (9) plant lineages were found. However, we failed to determine the temporal origin for 18 lineages because a stem-crown time interval overlaps with the 2.8-Ma threshold. The spatial origin of thermophilous lineages was also heterogeneous, including ancestral areas from the Mediterranean Basin (nine) and other regions (six). Our findings reveal an unexpectedly heterogeneous origin of the Canarian thermophilous species in terms of colonization times and mainland source areas. A substantial proportion of the lineages arrived in the Canaries before the summer-dry climate was established in the Mediterranean Basin. The complex temporal and geographic origin of Canarian thermophilous species challenges the view of the Canary Islands (and Madeira) as a subregion within the Mediterranean Floristic Region.

Sustainable Urban Logistics: different scales different solutions

The logistic sector is shaped by the location of human and economic activities, in brief, by land use. The freight flows between spatial origins and destinations result from initial decision taken by economic agents. Urban areas are continuously need goods while also generators of freight and waste. In the last two decades, public authorities recognized the need to organize urban distribution. Today, it is widely accepted that a strategic view over the evolution of urban logistics is inevitably associated with the type of city in terms of vocation, economic and social ambitions, demographics, and other elements that foster and/or condition the evolution of an urban area. It builds on the assumption that urban logistics is always part of the urban mobility system and, consequently, recognizes that individuals do a significant part of the logistic movements to satisfy their daily needs.