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Near-field microscopy discloses a peculiar potential to explore novel quantum state of matter at the nanoscale, providing an intriguing playground to investigate, locally, carrier dynamics or propagation of photoexcited modes as plasmons, phonons, plasmon-polaritons or phonon-polaritons. Here, we exploit a combination of hyperspectral time domain spectroscopy nano-imaging and detectorless scattering near-field optical microscopy, at multiple terahertz frequencies, to explore the rich physics of layered topological insulators as Bi 2 Se 3 and Bi 2 Te 2.2 Se 0.8 , hyperbolic materials with topologically protected surface states. By mapping the near-field scattering signal from a set of thin flakes of Bi 2 Se 3 and Bi 2 Te 2.2 Se 0.8 of various thicknesses, we shed light on the nature of the collective modes dominating their optical response in the 2-3 THz range. We capture snapshots of the activation of transverse and longitudinal optical phonons and reveal the propagation of sub-diffractional hyperbolic phonon-polariton modes influenced by the Dirac plasmons arising from the topological surface states and of bulk plasmons, prospecting new research directions in plasmonics, tailored nanophotonics, spintronics and quantum technologies. Propagation of photoexcited modes provides important information for novel quantum state. Here, the authors reveal the propagation of sub-diffractional hyperbolic phonon-polariton modes influenced by the Dirac plasmons in topological insulators.

Citrus is a subtropical fruit tree with high water requirements. This study aimed to determine the effects of water deficit on an orange orchard subjected to different water-saving strategies. The study was realised in an orange orchard in a semiarid area by adopting four different water management techniques: 100% crop evapotranspiration (control); SSDI—subsurface sustained deficit irrigation; RDI—regulated deficit irrigation; PRD—partial rootzone drying treatment during five growing seasons. The experimental design foresaw a randomised block design with six replicates per treatment (24 index plants). The results of the study showed that the water-saving strategies reduced irrigation water consumption by 25% (SSDI), 33% (RDI), and 49% (PRD) compared to the fully irrigated treatment without yield reduction, thus increasing water use efficiency. Mineral nutrition of the trees was slightly affected by irrigation treatments; element concentration in leaves was generally in the optimal range; only potassium showed values below the recommended leaf concentrations. Regarding fruit quality parameters, the vitamin C concentration in RDI showed significant differences with a value of 62.7 mg 100 mL−1 compared to 58.5 mg 100 mL−1 in the control. Plants subjected to SSDI and PRD strategies showed increased levels of pulp colour index with significant values of 10 and 9.90, respectively, compared to the control (8.44). By implementing targeted water management, citrus growers could save water and increase the ascorbic acid and sugar concentration in the fruits; anthocyanins also increased but not significantly. These findings open new market opportunities for citrus growers in marginal areas, where they cannot rely solely on producing citrus fruits to remain competitive.

In the terahertz (THz) range, due to the lack of effective THz light sources, chaos generation in THz semiconductor lasers, e.g., quantum cascade lasers (QCLs), is particularly challenging. Here, we experimentally demonstrate a THz chaos source based on a sole multimode THz QCL without any external perturbations. Such a dynamical regime is characterized by the largest Lyapunov exponent of the measured radio frequency signal of the laser. The experimental results are confirmed by our simulations based on effective semiconductor Maxwell-Bloch Equations. Furthermore, a reduced model based on two coupled complex Ginzburg-Landau equations is derived to systematically investigate the effects of the linewidth enhancement factor and group velocity dispersion on the chaotic regime. It is found that the chaos generation in the THz QCL is ascribed to the defect-mediated turbulence. Our findings pave the way for the generation of controllable and integrated THz chaos sources, as well as potential applications. Liu et al. experimentally demonstrate a terahertz chaos source based on a terahertz quantum cascade laser without any external perturbations. It is found that the chaos generation in the terahertz laser is ascribed to the defect-mediated turbulence.

We describe structure localization and dissipative solitons in a semiconductor laser with a saturable absorber exhibiting gain/absorption recovery times shorter than the photon lifetime. Under assumptions compatible with QCL characteristics and graphene-based absorbers, we study the existence and stability of solitons, along with their dynamical behavior. Numerical simulations confirm the robustness of our predictions. This evidence hints at promising pathways to realize passive mode locking in ultrafast lasers, implying highly valuable application prospects.

Soil amendments (e.g., compost) require uniform incorporation in the soil profile to benefit plants. However, machines may not mix them uniformly throughout the upper soil layer commonly explored by plant roots. The study focuses on using image texture analysis to determine the level of mixing uniformity in the soil following the passage of two kinds of harrows. A 12.3-megapixel DX-format digital camera acquired images of soil/expanded polystyrene (in the laboratory) and soil/compost mixtures (in field conditions). In the laboratory, pictures captured the soil before and during the simulated progressive mixing of expanded polystyrene particles. In field conditions, images captured the exposed superficial horizons of compost-amended soil after the passage of a combined spike-tooth–disc harrow and a disc harrow. Image texture analysis based on the gray-level co-occurrence matrix calculated the sums of dissimilarity, contrast, entropy, and uniformity metrics. In the laboratory conditions, the progressive mixing resulted in increased image dissimilarity (from 1.15 ± 0.74 × 106 to 1.65 ± 0.52 × 106) and contrast values (from 2.69 ± 2.06 × 106 to 5.67 ± × 1.93 106), almost constant entropy (3.50 ± 0.25 × 106), and decreased image uniformity (from 6.65 ± 0.31 × 105 to 4.49 ± 1.36 × 105). Using a tooth-disc harrow in the open field resulted in higher dissimilarity, contrast, entropy (+73.3%, +62.8%, +16.3%), and lower image uniformity (−50.6%) than the disc harrow, suggesting enhanced mixing in the superficial layer.

In this retrospective compendium, we attempt to draw a “fil rouge” along fifteen years of our research in the field of optical feedback interferometry aimed at guiding the readers to the verge of new developments in the field. The general reader will be moved at appreciating the versatility and the still largely uncovered potential of the optical feedback interferometry, for both sensing and imaging applications. By discovering the broad range of available wavelengths (0.4–120 μm), the different types of suitable semiconductor lasers (Fabry–Perot, distributed feedback, vertical-cavity, quantum-cascade), and a number of unconventional tenders in multi-axis displacement, ablation front progression, self-referenced measurements, multispectral, structured light feedback imaging and compressive sensing, the specialist also could find inspirational suggestions to expand his field of research.

The mechanization of wheat harvesting in Egypt is a critical step towards enhancing food security. This study evaluated the operational performance, grain loss, and economic viability of four wheat harvesting systems for the ‘Sakha 95’ variety in the Nile Delta. To evaluate and rank the different systems based on multiple criteria, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was employed. A Randomized Complete Block Design (RCBD) with three replicates was used to test three self-propelled combine harvesters (Claas [4.2 m], Field-King [2.0 m], Daedong [1.4 m]) alongside one semi-mechanized system (reaper–binder + stationary thresher). The TOPSIS analysis identified the Field King combine as the most recommended system (Rank 1), providing the optimal balance between operational efficiency and cost. It achieved the lowest direct harvesting cost (3386.66 EGP ha−1) with a minimal grain loss of only 0.05%. The Claas combine secured Rank 2. While it reached the highest effective field capacity (1.18 ha h−1) and near-total grain recovery (0.005% loss), its ranking was influenced by its high initial purchase price and fuel consumption. The reaper–binder system (Rank 3) and Daedong combine (Rank 4) followed. Despite having the highest operational cost (7371.42 EGP ha−1) and higher grain losses (0.72%), the reaper–binder remains a scientifically justified choice for integrated crop-livestock systems, as its ability to produce ready-to-use “soft straw” provides a net economic advantage for smallholders. The study concludes that while large combines are ideal for the “New Lands,” mid-sized units like the Field King are best suited for scaling through cooperatives in fragmented landscapes.

The optimization of energy input on agricultural farms, such as through improved fuel consumption, is currently under investigation in agricultural mechanization research with the aim of achieving economic and environmental goals. In previous research, we developed a simplified algorithm focused on defining the most efficient tractor–implement combination considering the factors that most influence this aspect. The ASABE (American Society of Agricultural and Biological Engineers) equation for calculating the drawbar pull force was adopted to fit the results to the soil conditions. Agricultural tires of different sizes were tested at different pressure settings under field conditions to assess differences in drawbar force. The resulting algorithm underwent a linear regression analysis to achieve a simplified equation for assessing the optimal wheel-slip, mass, engine power, and tire pull force properties during drawbar works that result in optimal fuel consumption with a minimal tractor efficiency impairment. Using a specific probability density function, the Monte Carlo Simulation method introduced randomness into the input and runs a sufficiently large number of trials to identify the most probable output. The result is a simplified algorithm that can be used to investigate the effects of certain parameters on fuel consumption; however, it can be adapted to evaluate the effects of different implements, tires, engine settings, or fleet management methods on fuel consumption.

Automation reduces the impact of farming on climate change and helps farmers adapt to its financial impact. Automatic feeding systems (AFSs) increase the ruminant’s feeding precision and ease operators’ workload. Such systems exist on a spectrum, requiring varied levels of operator support and installation complexity. A recent survey on farmers pointed out that those already running an AFS and those willing to buy one appreciate its ease of use, the resulting animal welfare, and the resulting overall benefits (increased production, farm profitability, and reduced feed waste). Whether technologically complex or not, studies have confirmed the benefits that farmers perceive to be underlying the remarkable reduction in the environmental impact of feeding operations (AFSs are electrically powered), the increase in animal welfare resulting from reduced conflicts around accessing the feed bunk, and the constant availability of fresh feed. However, their introduction should follow accurate and holistic structural and economic planning for existing and newly built facilities. The availability of public subsidies plays an essential role in pushing farmers to adopt the most modern digital technologies, whose benefits may even increase when farmers couple them with interconnected sensors to monitor animals’ physiological states.