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Abstract In order to better understand manifold neural networks (MNNs), we introduce Manifold Filter-Combine Networks (MFCNs). Our filter-combine framework parallels the popular aggregate-combine paradigm for graph neural networks (GNNs) and naturally suggests many interesting families of MNNs which can be interpreted as manifold analogues of various popular GNNs. We propose a method for implementing MFCNs on high-dimensional point clouds that relies on approximating an underlying manifold by a sparse graph. We then prove that our method is consistent in the sense that it converges to a continuum limit as the number of data points tends to infinity, and we numerically demonstrate its effectiveness on real-world and synthetic data sets. 

This study explores the effects of alternating current-induced electromagnetic field (EMF) on mitigating brackish water irrigation and soil salinization impacts. Greenhouse experiments were conducted to evaluate the effect of EMF on plant growth, soil properties, and leaching of ions under different conditions, including using brackish water and desalinated water for irrigation and soil compost incorporation. The experiment was performed with four types of irrigation water using soil columns representing field soil layers. EMF-treated brackish water maintained a sodium adsorption ratio of 2.7 by leaching Na+ from the soil. EMF-treated irrigation columns showed an increase in soil organic carbon by 7% over no EMF-treated columns. Compost treatment reduced the leaching of NO3− from the soil by more than 15% using EMF-treated irrigation water. EMF-treated brackish water and compost treatment enhanced plant growth by increasing wet weight by 63.6%, dry weight by 71.4%, plant height by 22.8%, and root length by 115.8% over no EMF and compost columns. EMF-treated agricultural water without compost also showed growth improvements. The findings suggest that EMF treatment, especially combined with compost, offers an effective, low-cost, and eco-friendly solution to mitigate soil salinization, promoting plant growth by improving nutrient availability and soil organic carbon. 

Increasing soil salinity and degraded irrigation water quality are major challenges for agriculture. This study investigated the effects of irrigation water quality and incorporating compost (3% dry mass in soil) on minimizing soil salinization and promoting sustainable cropping systems. A greenhouse study used brackish water (electrical conductivity of 2010 µS/cm) and agricultural water (792 µS/cm) to irrigate Dundale pea and clay loam soil. Compost treatment enhanced soil water retention with soil moisture content above 0.280 m3/m3, increased plant carbon assimilation by ~30%, improved plant growth by >50%, and reduced NO3− leaching from the soil by 16% and 23.5% for agricultural and brackish water irrigation, respectively. Compared to no compost treatment, the compost-incorporated soil irrigated with brackish water showed the highest plant growth by increasing plant fresh weight by 64%, dry weight by 50%, root length by 121%, and plant height by 16%. Compost treatment reduced soil sodicity during brackish water irrigation by promoting the leaching of Cl− and Na+ from the soil. Compost treatment provides an environmentally sustainable approach to managing soil salinity, remediating the impact of brackish water irrigation, improving soil organic matter, enhancing the availability of water and nutrients to plants, and increasing plant growth and carbon sequestration potential. 

Understanding and characterizing the intrinsic properties of charge carrier transport across the interfaces in van der Waals heterostructures is critical to their applications in modern electronics, thermoelectrics, and optoelectronics. However, there are very few published cross-plane resistivity measurements of thin samples because these inherently 2-probe measurements must be corrected for contact and lead resistances. Here, we present a method to extract contact resistances and metal lead resistances by fitting the width dependence of the contact end voltages of top and bottom electrodes of different linewidths to a model based on current crowding. These contributions are then subtracted from the total 2-probe cross-plane resistance to obtain the cross-plane resistance of the material itself without needing multiple devices and/or etching steps. This approach was used to measure cross-plane resistivities of a (PbSe)1(VSe2)1 heterostructure containing alternating layers of PbSe and VSe2 with random in-plane rotational disorder. Several samples measured exhibited a 4 order of magnitude difference between cross-plane and in-plane resistivities over the 6–300 K temperature range. We also reported the first observation of charge density wave transition in the cross-plane transport of (PbSe)1(VSe2)1 heterostructure. The device fabrication process is fully lift-off compatible, and the method developed enables the straightforward measurement of the resistivity anisotropy of most thin film materials with nm thicknesses. 

The resource‐availability hypothesis (RAH) and the intraspecific RAH (RAH intra ), posit that resources, (i.e. nutrients) control plant antiherbivore defenses. Both hypotheses predict that in low‐resource environments, plant growth is slow, and constitutive defense is high. In high‐resource environments, however, the RAH predicts that plant growth is fast, and constitutive defense is low, whereas the RAH intra predicts that increased resources attract more herbivores, and this intensified grazing pressure leads to high constitutive defense. Salt marshes are nutrient‐limited ecosystems threatened by eutrophication and chronic herbivory, yet we know little about how these stressors shape saltmarsh plant antiherbivore defenses, which influence trophic interactions and ecosystem resilience. We manipulated resource availability via nutrient addition and herbivory via the marsh periwinkle Littoraria irrorata , on the saltmarsh foundation species Spartina alterniflora , in mesocosms. Because plant age can also influence trait variation, we measured traits in both original and clonally‐grown new stems. Feeding assays then evaluated how treatments and plant age affected subsequent Littoraria consumption of Spartina . Nutrient addition stimulated growth, while decreasing defensive traits (e.g. fiber and silica content), following the RAH. Herbivory enhanced belowground production and increased stem diameter, yet did not induce defensive traits, contrary to our expectations. Herbivory plus nutrients increased Spartina biomass and reduced phenolics, a defensive trait, further supporting the RAH. Regardless of treatment, clonally‐grown new stems had greater variation in measured traits. Despite altered traits, however, treatments and plant age did not affect Littoraria consumption. Our results support the RAH and part of the RAH intra and suggest: 1) nutrient availability is a primary driver of plant trait change and 2) plant age controls the magnitude of trait variation in Spartina . Further, our findings indicate that eutrophic conditions may not always increase top‒down control by herbivores, and in some instances can enhance saltmarsh resilience against sea‐level rise via stimulated Spartina biomass production.