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As urban heatwaves become more severe, frequent and longer, cities seek adaptive building cooling measures. Although passive building design, energy-efficient materials and technologies and mechanical means are proven cooling methods, the potential of naturebased solutions (particularly trees as shading elements) has been understudied despite its significant opportunity. Using a new framework to explore this at the neighbourhood level, three future (2050) potential tree planting strategies are modelled for increasing tree volume and canopy cover and their impacts assessed for summer building-level solar radiation absorption (SRA) and building cooling energy demand (BCED) for a densifying neighbourhood in Vancouver, Canada. The boldest tree planting strategy, with 287% more trees than baseline and 16% canopy cover, reduced neighbourhood-scale total SRA (22%) and BCED (48%) over a no-trees scenario. BCED reductions of up to 64% for retrofitted/redeveloped buildings and 53-79% for low/medium-height buildings (mostly single-family residential) were associated with targeted south-side tree planting. Taller/larger buildings (predominantly mixed use) and buildings along north-south-oriented streets (mainly commercial and mixed use) encountered more tree shading challenges and would require more site-specific interventions. The methodology presented provides a framework to assess current and potential future shading and cooling energy benefits through various tree planting strategies. [ABSTRACT FROM AUTHOR]

Weakly supervised shadow detection has been spreading as cheaper labeling costs in recent years. However, these works tend to use a single annotation manner, i.e., scribble, it may not be the best choice for each shadow scene and thereby cannot exploit more valuable cues for better training. To tackle this issue, this work explores a more flexible labeling strategy, containing scribble, box and point. During the training, rather than only using cross-entropy (CE) loss on the available points, we formulate the supervisions between given annotations with the model's predictions as a bipartite matching problem, and then design efficient weak learning losses from other valuable perspectives of shadow location, quantity and size. Moreover, considering the challenge of poor boundary localization in one-stage weakly supervised image segmentation, we propose a CNN-assisted tuning strategy to inherit boundary knowledge from the vision foundation model (i.e. , SAM), and learn task-specific knowledge from our hybrid annotations by introducing a light-weight CNN branch along with the SAM backbone, namely ShadowSAM. This approach has lower requirements on GPU memory and extracts more local information for identifying tiny shadow regions. Extensive experiments demonstrate that our proposed methods can achieve comparable performance with state-of-the-art (SOTA) fully supervised shadow detectors. Our code will be available at https://github.com/wuwen1994/omni-shadow. [ABSTRACT FROM AUTHOR]

To further improve the efficiency of the wafer-based silicon photovoltaic (PV) module, producers are introducing new module designs with cut-cells. Since smaller solar cells might be affected by partial shading even more and earlier than full-size cells, the energy performance simulations of partially shaded modules are crucial. A detailed shading analyses of partially shaded modules with different cut cell designs are presented not only on a single case scenario but on annual energy yield simulations using Spice, where a shading scenario over the whole module by the use of a new 3D shading horizon profile of selected shading objects is calculated. The annual simulations reveal that regardless the module design almost all cells in the module are confronted by reverse bias, which can deteriorate the module performance significantly. Simulation results with three different shading objects on five different module topologies at five locations showed that the best cut-cell module design depends strongly by the micro location and shading objects; however, in general the string of solar cells connected in series should be aligned with the shading shape around noontime as much as possible. A comprehensive annual energy performance evaluation of partially shaded cut-cell modules revealed; that with a correct cell layout of cut-cells in a PV module, the shading losses can be reduced by 30–50% if comparing to the standard PV module design. • Annual energy performance model of partially shaded modules. • Energy balance model for partially shaded modules. • Comprehensive electrical evaluation of the partially shaded module on the cell level. [ABSTRACT FROM AUTHOR]

In this article, a new maximum power point tracking algorithm based on a modified butterfly optimization algorithm has been proposed. The proposed method is capable of differentiating between different partial shading patterns, uniform shading, solar intensity, and load variation conditions with fast convergence speed (CS). Only one dynamic variable is used as a tuning parameter reducing the complexity of the algorithm. The search space skipping method has been proposed to improve the CS. The proposed method is hybridized with a constant impedance method to improve the response time of the system for fast varying load variations. The proposed method has been validated experimentally on the SEPIC converter topology with a sampling time of 0.05 s. The experimental validation proved the average tracking time for different shading patterns is less than 1 s with steady-state efficiency of 99.85% on average. The CS for uniform shading conditions is improved by 47.20%. The response to load variation is also improved by 86.15% and becomes eligible to be utilized for fast varying load variations. Finally, the comparison table based on the MPPT rating has been presented to determine the effectiveness of the proposed method among other popular metaheuristic approaches used for MPPT. [ABSTRACT FROM AUTHOR]

The aim here is to shape our impression of rough surfaces based on the formation of shadows. The shadows blackout some parts of the surface leading us to state that rough surfaces are not always quite the way they seem. In fact, it is the angle of view that proves the size of the shadows. In surface profilometry, the scanned image is produced by a vertical shot. While in nature, a vertical sighting of events is not always possible or preferred, therefore readings by various observers would depend on the angle of their line of sight. In the present work, owing to the statistical properties of rough surfaces, the relation between a vertical and angular line of site view of a surface is obtained. This enables the estimation of how the surface really looks like, even though the observer has an non vertical line of sight. To be most illustrative, a comparison between wave scattering from an actual surface and that from an observed surface is performed. The shadowing effects which are shown to be inversely proportional to the Hurst exponent, cause the height correlation function to posses a bi-scaling behaviour. We also illustrate how the correlation develops its efficiency as the line of sight angle tends to zero, making the surface look smooth. [ABSTRACT FROM AUTHOR]

Partial shading is an important subject for the research community to improve the issues in the field of solar array utilization. Shading decreases the life of photovoltaic array, its output power yield, and also generates several peaks in its P–V characteristic curves. Physical relocation of panels can be used as a practical solution to prevent such problems by altering the location of panels but not its electrical circuit. In this article, a reconfiguration technique for all conventional configurations like, series-parallel, bridge-link, honey comb, and total cross tied connections are proposed to reduce current difference between the rows and to improve the irradiance equalization by dispersing the shade. This article proposes a mathematical Tom-Tom puzzle pattern for $5\times 5$ array to enhance the output parameters. The performance of all configurations is evaluated with artificially generated shading to resemble moving clouds which are incremented progressively in row-wise and diagonal manner. From the extensive analysis of results, it has been found that the proposed reconfigurations show better performance than its respective static configurations. The proposed configuration is also tested in terms of income generated and a comparison with the existing state-of-art methods to show the supremacy of the proposed approach. [ABSTRACT FROM AUTHOR]

Cloud and cloud shadow segmentation of satellite imageries is a prerequisite for many remote sensing applications. Due to the limited number of available spectral bands and the complexity of background information, the traditional detection methods have some problems such as false detection, missing detection and inaccurate boundary information in segmentation. To solve these problems, a global attention fusion residual network method is proposed to segment cloud and cloud shadow of satellite imageries. The proposed model adopts Residual Network (ResNet) as backbone to extract semantic information at different feature levels. In order to improve the ability of the network to deal with the boundary information, an improved atrous spatial pyramid pooling method is introduced to extract the multi-scale deep semantic information. Then, the deep semantic information is fused with the shallow spatial information through the Global Attention up-sample mechanism in different scales, which improves the network's ability to utilize the global and local features. Finally, a boundary refinement module is utilized to predict the boundary of cloud and shadow, consequently the boundary information is refined. The experimental results on Sentinel-2 satellite and Land Remote-Sensing Satellite (Landsat) imageries show that the segmentation accuracy and speed of proposed method are superior to the existing methods, it is of great significance for realizing practical cloud and shadow segmentation. [ABSTRACT FROM AUTHOR]

Accreting black holes tend to display a characteristic dark central region called the black hole shadow, which depends only on space–time/observer geometry and which conveys information about the black hole's mass and spin. Conversely, the observed central brightness depression, or image shadow, additionally depends on the morphology of the emission region. In this paper, we investigate the astrophysical requirements for observing a meaningful black hole shadow in GRMHD-based models of accreting black holes. In particular, we identify two processes by which the image shadow can differ from the black hole shadow: evacuation of the innermost region of the accretion flow, which can render the image shadow larger than the black hole shadow, and obscuration of the black hole shadow by optically thick regions of the accretion flow, which can render the image shadow smaller than the black hole shadow, or eliminate it altogether. We investigate in which models the image shadows of our models match their corresponding black hole shadows, and in which models the two deviate from each other. We find that, given a compact and optically thin emission region, our models allow for measurement of the black hole shadow size to an accuracy of 5 per cent. We show that these conditions are generally met for all MAD simulations we considered, as well as some of the SANE simulations. [ABSTRACT FROM AUTHOR]

Shadows, in aerial and satellite high-resolution images of earth, are a common phenomenon. Shadow causes false-color image, loss of information in the image, and false image segmentation. This leads to incorrect outputs of many image processing applications. In this paper, we address the problem of shadow detection in aerial high-resolution images of earth. The paper presents a proposed method that can be valuable in comparing it with other existing methods. The proposed work exploits the impact of ratio image pixel values on the process of shadow detection. The ratio image is the mathematical division of hue over the intensity component in the invariant color model. We propose a method, design, and develop an algorithm. In the designed algorithm, the input RGB aerial image of the earth is transformed into the invariant color model hue, saturation, and value (HSV). It acquires the average intensity value of pixels of the input RGB image components. Then, the ratio image of Hue (H) over Value (V) is calculated. Afterward, a power function is applied to this ratio to modify it by increasing the difference between pixel values very effectively. Finally, a threshold is applied to the modified ratio image to classify pixels into shadow and nonshadow. The proposed power function helps the threshold to better classify pixels into shadow and nonshadow. It has been implemented and experimented extensively. A comparative study has also been made with existing methods in the literature. In comparing the proposed algorithm and some existing algorithms, the experimental results show that the proposed has the ability to detect shadows with satisfying accuracy. [ABSTRACT FROM AUTHOR]

Recent observations have revealed that most proto-planetary discs show a pattern of bright rings and dark gaps. However, most of the high-resolution observations have focused only on the continuum emission. In this paper, we present high-resolution ALMA band 7 (0.89 mm) observations of the disc around the star CI Tau in the 12CO & 13CO J  = 3–2 and CS J  = 7–6 emission lines. Our recent work demonstrated that the disc around CI Tau contains three gaps and rings in continuum emission, and we look for their counterparts in the gas emission. While we find no counterpart of the third gap and ring in 13CO, the disc has a gap in emission at the location of the second continuum ring (rather than gap). We demonstrate that this is mostly an artefact of the continuum subtraction, although a residual gap still remains after accounting for this effect. Through radiative transfer modelling, we propose this is due to the inner disc shadowing the outer parts of the disc and making them colder. This raises a note of caution in mapping high-resolution gas emission lines observations to the gas surface density – while possible, this needs to be done carefully. In contrast to 13CO, CS emission shows instead a ring morphology, most likely due to chemical effects. Finally, we note that 12CO is heavily absorbed by the foreground preventing any morphological study using this line. [ABSTRACT FROM AUTHOR]

Regions of permanent shadow at the lunar poles have been suggested to host water ice and potentially other volatile compounds owing to their extremely low temperatures. Imaging in permanent shadow using indirect lighting from nearby topographic highs illuminated by the Sun has demonstrated the feasibility of optical remote sensing of permanent shadow surfaces, and a near-IR detection of water ice spectral features demonstrates the ability to collect usable spectroscopic data. The infrared emission of the lunar surface is largely in radiative equilibrium, so the temperature of surfaces in permanent shadow is driven by the intensity of the indirect illumination. This means that surfaces at very low temperatures, of high interest owing to their ability to trap and retain volatile compounds, will be the most challenging to measure. We provide estimates of indirect spectral radiance as a function of permanent shadow temperature from 400 nm to 14 μm using empirical data on permanent shadow temperature and broadband visible and near IR radiance, coupled with known reflectance properties of lunar materials. The relationships show there is ample radiance and photon radiance for reflectance imaging and spectroscopy from 400 nm to 8 μm at temperatures of regions of permanent shadow above 60K with appropriately designed instruments. Beyond 8 μm lunar spectral properties reduce the available radiance substantially, making reflectance observations challenging. • The spectral radiance of indirectly illuminated surfaces in permanently shadowed regions (PSRs) on the Moon. • We estimate spectral radiance available in PSRs at the lunar poles. • There is ample radiance for imaging and spectroscopy from 400 nm to 8 μm. • Reflectance observations beyond 8 μm will be challenging. [ABSTRACT FROM AUTHOR]

Aralia elata (Miq.) Seem is widely used as a medicinal plant and functional food in China. In this study, A. elata plants were exposed to full sunlight (CK), 40% shading (LS), 60% shading (MS), and >80% shading (ES) condition to investigate the effects of shading treatments on growth, stress levels, antioxidant enzymes activity, araloside content and related gene expression. The greatest growth and leaf biomass were achieved in 40% shading, and leaf biomass per plant increased by 16.09% compared to the non-shading treatment. Furthermore, the lowest reactive oxide species (ROS) production and lipid peroxidation resulting from increasing antioxidant enzyme activity were also observed in LS treatment. Overall, shading percentage negatively regulated the expression of key enzymes (squalene synthase, SS; squalene epoxidase, SE and β-amyrin synthase, bAS) involved in the saponin biosynthesis, resulting in the greatest yields of total and four selected aralosides in A. elata leaves were achieved in sunlight group. However, the greatest yield of total saponin in the leaves was observed in the 40% shading group due to higher leaf biomass. The results suggest that optimizing the field growing conditions would be important for obtaining the greatest yield of bioactive components. Total saponin and selected aralosides also have a significant correlation with ROS production and antioxidant enzyme activity, these indicated the increased yield of these saponins may be part of a defense response. The study concludes that the production of saponin was the interaction of oxidative stress and photosynthesis. • Aralia. elata was a typical shade plant suitable to grow under lower light shading (40% shading). • Higher light irradiation stimulated triterpene saponin accumulation and related genes expression. • The production of triterpene saponin was the interaction of oxidative stress and photosynthesis. [ABSTRACT FROM AUTHOR]

Shade is a mechanism to reduce heat load providing cattle with an environment supportive of their welfare needs. Although heat stress has been extensively reviewed, researched, and addressed in dairy production systems, it has not been investigated in the same manner in the beef cattle supply chain. Like all animals, beef cattle are susceptible to heat stress if they are unable to dissipate heat during times of elevated ambient temperatures. There are many factors that impact heat stress susceptibility in beef cattle throughout the different supply chain sectors, many of which relate to the production system, that is, availability of shade, microclimate of environment, and nutrition management. The results from studies evaluating the effects of shade on production and welfare are difficult to compare due to variation in structural design, construction materials used, height, shape, and area of shade provided. Additionally, depending on operation location, shade may or may not be beneficial during all times of the year, which can influence the decision to make shade a permanent part of management systems. Shade has been shown to lessen the physiologic response of cattle to heat stress. Shaded cattle exhibit lower respiration rates, body temperatures, and panting scores compared with unshaded cattle in weather that increases the risk of heat stress. Results from studies investigating the provision of shade indicate that cattle seek shade in hot weather. The impact of shade on behavioral patterns is inconsistent in the current body of research, with some studies indicating that shade provision impacts behavior and other studies reporting no difference between shaded and unshaded groups. Analysis of performance and carcass characteristics across feedlot studies demonstrated that shaded cattle had increased ADG, improved feed efficiency, HCW, and dressing percentage when compared with cattle without shade. Despite the documented benefits of shade, current industry statistics, although severely limited in scope, indicate low shade implementation rates in feedlots and data in other supply chain sectors do not exist. Industry guidelines and third-party on-farm certification programs articulate the critical need for protection from extreme weather but are not consistent in providing specific recommendations and requirements. Future efforts should include: updated economic analyses of cost vs. benefit of shade implementation, exploration of producer perspectives and needs relative to shade, consideration of shade impacts in the cow–calf and slaughter plant segments of the supply chain, and integration of indicators of affective (mental) state and preference in research studies to enhance the holistic assessment of cattle welfare. [ABSTRACT FROM AUTHOR]

Agroforestry systems are reported as climate‐resilient productive systems, but it is yet unclear how tree shade affects crops performance. The aim of this work was to assess how the phenology, plant traits and grain yield of wheat and barley were affected by shade. In an open greenhouse experiment, we cultivated in pots nine cultivars differing in precocity for each species and imposed three artificial shading levels (S0 ~ 0%, S1 ~ 25%, S2 ~ 50%) at the start of cereal booting. Our results showed that shade speeded up first growth stages in both species, until the starting of milk development. Barley showed consistent phenological responses to the three irradiance levels among cultivars, but not wheat that showed larger phenological differences among cultivars at moderate shade. Deep shade prolonged the time needed for wheat grain ripening. Both species increased grain yield by 15%–20% with shade, driven by shade‐acclimations of plant traits that differed among species. For wheat, grain yield was determined by the assemblage of traits that contribute to yield, such as grain weight, precocity and non‐photochemical quenching, while, for barley, SPAD value, precocity to reach phenological stages, grains per spike and plant height had the strongest influence. These traits varied widely among cultivars and seem of interest to identify best suited cultivars for shading conditions of Mediterranean agroforestry systems. [ABSTRACT FROM AUTHOR]

High dynamic range (HDR) workflows provide increased peak luminance and lower black levels leading to a significantly enhanced quality of experience. HDR pixels also represent more tonal values across the dynamic range by using a higher bit‐depth along with different perceptual transfer functions. However, many light‐emitting display devices modulate light using a limited bit‐depth in the linear domain. It is thus challenging for such display systems to achieve simultaneously high peak luminance and high amount of information in the shadows. In this paper, we summarize pulse‐width modulation (PWM) principles and its impact on low black level reproduction. We then assess the required bit‐depth to accurately reproduce shadow information of an HDR signal for different display capabilities. Finally, we describe several technology improvements that could improve the tonal level reproduction of PWM‐driven displays. [ABSTRACT FROM AUTHOR]

An experiment was set up to investigate physiological responses of soybeans to silicon (Si) under normal light and shade conditions. Two soybean varieties, Nandou 12 (shade resistant), and Nan 032–4 (shade susceptible), were tested. Our results revealed that under shading, the net assimilation rate and the plant growth were significantly reduced. However, foliar application of Si under normal light and shading significantly improved the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and decreased intercellular carbon dioxide concentration (Ci). The net photosynthetic rate of Nandou 12 under normal light and shading increased by 46.4% and 33.3% respectively with Si treatment (200 mg/kg) compared to controls. Si application also enhanced chlorophyll content, soluble sugars, fresh weight, root length, root surface area, root volume, root-shoot ratio, and root dry weight under both conditions. Si application significantly increased the accumulation of some carbohydrates such as soluble sugar and sucrose in stems and leaves ensuring better stem strength under both conditions. Si application significantly increased the yield by increasing the number of effective pods per plant, the number of beans per plant and the weight of beans per plant. After Si treatment, the yield increased 24.5% under mono-cropping, and 17.41% under intercropping. Thus, Si is very effective in alleviating the stress effects of shading in intercropped soybeans by increasing the photosynthetic efficiency and lodging resistance. Image 1 • Si potentially improves root architecture in intercropping. • Si increases photosynthesis and stomatal conductance under shading. • Foliar application of Si enhances soluble sugars and sucrose in leaves. • Si plays a role in alleviating drastic effects of shading stress. [ABSTRACT FROM AUTHOR]

• Evaluation of insolation when BIPV panel is subjected to shadow due to adjacent buildings. • Optimum azimuth and tilt angle of BIPV panel for harnessing maximum insolation. • Optimum azimuth angle changes with change in plan orientation of adjacent building. • Efficiency of the BIPV panel increases when water is assumed to be flown over it. Development of a BIPV system with appropriate azimuth and tilt angle on top of a suitable existing or new building in urban areas is a possible option to generate both electrical and thermal energies and also to create an additional living space. These azimuth and tilt angles are significantly influenced by the shadow of the neighborhood's buildings. The relative height, plan orientation, plan area, position, and horizontal distance of the neighborhood's buildings are critical parameters for determining optimum azimuth and tilt angle to receive maximum insolation. Present proposed model accurately calculates these angels and the energy, and the model also works well when water flows over the BIPV panel from an overhead tank through gravity with an aim to increase the efficiency of PV panel. The periodic nature of relevant parameters is considered in the thermal modeling of the BiSPVT system. Results indicate that the optimum azimuth angle from south-facing increases with a rise in the latitude angle of the place. The optimum tilt angle depends on the corresponding latitude and the different contributing parts of total insolation. The electrical output of a south-facing BiSPVT system with a tilt angle equal to latitude is increased by 3.7% when BiSPVT system is installed at optimum azimuth and tilt angle. The output is further enhanced by 4.3% when water is flown at the rate of 1.1 kgs−1 over the PV panel. [ABSTRACT FROM AUTHOR]

• Faces can be discriminated using basic visual patterns inherent in facial shading. • Discrimination of these patterns correlates with general facial recognition ability. • Faces illuminated from above are more easily recognised than those lit from below. • Variation in the horizontal lighting direction worsens recognition performance. The pattern of shadows and shading across a face is determined partly by face shape and may therefore provide a cue for facial recognition. In this study, we measured the ability of human observers to discriminate facial identity based simply on the coarse pattern of contrast produced by the interaction between facial geometry and lighting direction. We used highly realistic 3D models of human heads to create images of faces illuminated from different horizontal and vertical directions, which were then converted to two-tone images ('Mooney faces') to isolate the coarse pattern of contrast. Participants were presented with pairs of two-tone faces and judged whether it was the same person in both images. Participants could discriminate facial identity based on the minimal cues within the two-tone images, though sensitivity depended on the horizontal and vertical lighting direction. Performance on the Mooney recognition task correlated with general facial recognition ability, though the role of face-specific processing in this relationship was not significant. Our results demonstrate that shading information in the form of simple contrast cues is sufficient for discriminating facial identity, and support the idea that visual processing is somewhat optimised for overhead lighting – here, in the relatively high-level context of face identity recognition. [ABSTRACT FROM AUTHOR]

Causal concept for the general black hole shadow is investigated, instead of the photon sphere. We define several 'wandering null geodesics' as complete null geodesics accompanied by repetitive conjugate points, which would correspond to null geodesics on the photon sphere in Schwarzschild spacetime. We also define a 'wandering set', that is, a set of totally wandering null geodesics as a counterpart of the photon sphere, and moreover, a truncated wandering null geodesic to symbolically discuss its formation. Then we examine the existence of a wandering null geodesic in general black hole spacetimes mainly in terms of Weyl focusing. We will see the essence of the black hole shadow is not the stationary cycling of the photon orbits which is the concept only available in a stationary spacetime, but their accumulation. A wandering null geodesic implies that this accumulation will be occur somewhere in an asymptotically flat spacetime. [ABSTRACT FROM AUTHOR]

Under partial shading conditions, photovoltaic (PV) arrays are subjected to different irradiance levels caused by nonuniform shading. As a result, a mismatch between the modules, a reduction in the power generated, and the hotspot phenomenon will be observed. One method to reduce mismatch losses is to reconfigure the total-cross-tied (TCT) array in dynamic and static forms, where improved performance can be achieved through more efficient shading distribution thanks to increased dimensions. However, the increase in dimensions leads to the complexity of wiring and installation in static reconfiguration and the large number of switches and sensors required in dynamic reconfiguration. To rectify these problems, a two-step method is proposed in this paper. In the first step, the modules inside the PV array are divided into subarrays with wiring in static reconfiguration, rather than being wired as large-scale PV arrays. In the second step, an algorithm is developed for dynamic reconfiguration. The introduced algorithm searches for all possible connections and finally identifies the most optimal solution. As an advantage, this algorithm employs only the short-circuit current values of the subarray rows, which reduces the number of switches and sensors required in comparison to dynamic reconfiguration. Under 8 different partial shading patterns, simulations are conducted and results confirm that the proposed method outperforms the TCT array and statically modified TCT array in terms of power and mismatch losses. Among these, the highest power improvement is obtained with regard to the TCT array and statically modified TCT array under the fourth and eighth shading patterns, respectively. [ABSTRACT FROM AUTHOR]

Shading can effectively reduce photoinhibition and improve the quality of tea. Lignin is one of the most important secondary metabolites that play vital functions in plant growth and development. However, little is known about the relationship between shading and xylogenesis in tea plant. To investigate the effects of shading on lignin accumulation in tea plants, 'Longjing 43' was treated with no shading (S0), 40% (S1) and 80% (S2) shading treatments, respectively. The leaf area and lignin content of tea plant leaves decreased under shading treatments (especially S2). The anatomical characteristics showed that lignin is mainly distributed in the xylem of tea leaves. Promoter analysis indicated that the genes involved in lignin pathway contain several light recognition elements. The transcript abundances of 12 lignin-associated genes were altered under shading treatments. Correlation analysis indicated that most genes showed strong positive correlation with lignin content, and CsPAL, Cs4CL, CsF5H, and CsLAC exhibited significant positively correlation under 40% and 80% shading treatments. The results showed that shading may have an important effect on lignin accumulation in tea leaves. This work will potentially helpful to understand the regulation mechanism of lignin pathway under shading treatment, and provide reference for reducing lignin content and improving tea quality through shading treatment in field operation. [ABSTRACT FROM AUTHOR]

The depth image generated by Kinect sensor always contains vibration and shadow noises which limit the related usage. In this research, a method based on image fusion and fractional differential is proposed for the vibration filtering and shadow detection. First, an image fusion method based on pixel level is put forward to filter the vibration noises. This method can achieve the best quality of every pixel according to the depth images sequence. Second, an improved operator based on fractional differential is studied to extract the shadow noises, which can enhance the boundaries of shadow regions significantly to accomplish the shadow detection effectively. Finally, a comparison is made with other traditional and state-of-the-art methods and our experimental results indicate that the proposed method can filter out the vibration and shadow noises effectively based on the F -measure system. [ABSTRACT FROM AUTHOR]

Native tree species present different responses depending on their adaptability to varying degrees of sunlight. The objective of this study was to evaluate the growth of Myrocarpus frondosus seedlings under different shade conditions in a nursery. The experimental design included randomized blocks in a factorial scheme, corresponding to treatments of full sun (0%), or one of three shading intensities (30%, 50%, and 70%), with evaluation times of 30, 90, 150, 210, 270, 330, and 390 days after emergence - d.a.e. The evaluation of the morphological attributes height (H) and stem diameter (SD) were determined every 60 days, and H/SD ratio were calculated. At 390 d.a.e, the following attributes were evaluated: aerial dry matter, (ADM), root dry matter (RDM), total dry matter, (TDM), Dickson quality index (DQI), leaf area (LA), root volume (RV), and root length. The pigment contents of chlorophyll a, chlorophyll b, and chlorophyll a/b ratio were also identified, along with carotenoid content, maximum quantum yield PSII (Fv/Fm), and electron transport rate (ETR). Myrocarpus frondosus requires shading in its initial stage of growth, at an ideal intensity of 50% or 70% for producing seedlings. [ABSTRACT FROM AUTHOR]

One crucial problem in relativistic astrophysics is that of the nature of black hole candidates. It is usually assumed that astrophysical black holes are described by the Schwarzschild or Kerr space–times; however, there is no direct evidence to assert this. Moreover, there are various solutions in general relativity that can be alternatives to black holes, usually called black hole mimickers. In this work, we study the shadow produced by a compact object described by the q-metric, which is the simplest static and axially symmetric solution of Einstein equations with a non-vanishing quadrupole moment. This particular space–time has the property of containing an independent parameter q, which is related to the compact object deformation. The solution corresponds to naked singularities for some specific values of this parameter. Additionally, we analyze the eigenvalues of the Riemann tensor using the SO(3, C) representation, which allows us to find, in an invariant way, regions where there may be repulsive effects. Furthermore, we numerically solve the motion equations to show the shadow, the Einstein ring, and the gravitational lensing to establish a possible signature of such repulsive effects. We found that as q is smaller, the Einstein ring decreases, but the shape is the same as the Schwarzschild black hole case. However, for values of q lower or equal than −0.5, repulsive gravitational effects appear in the gravitational lensing close to the compact object, where a strong dependence of the system to the initial conditions seems to take place. [ABSTRACT FROM AUTHOR]

The shade tolerance of black currants (Ribes nigrum cv. Consort) was studied by measuring the growth and productivity of mature plants in the field for three seasons under full sun or artificial shade netting in Urbana, IL. Shade treatments reduced photosynthetically active radiation (PAR) from 37% to 83%. Yield was not reduced in shade levels up to 65% but decreased by as much as 66% under 83% shade. Shade had minimal effect on stem rejuvenation in the first 2 years, but reduced rejuvenation in the third year from 14 new stems in full sun to eight new stems in 83% shade. Stem diameter decreased 8% to 19% with 83% shade, whereas no changes were observed in up to 65% shade. Plant height increased 5% to 8% from open sun to 83% shade. Specific leaf weight decreased and leaf area increased with shade. Powdery mildew severity increased with shade, and disease-resistant cultivars should be considered for understory crops. Our results indicate that growth and productivity of black currants can be maintained in moderate shade but shade levels beyond 65% will significantly reduce agronomic performance. [ABSTRACT FROM AUTHOR]

This essay explores the nature of light in terms of personal experience, but also its emotional, poetic, and philosophical implications. Even when Plato is not quoted, the myth of the cave is implicitly discussed, in terms of the meaning of light as that which literally illuminates and creates belonging and, at the same time, also produces shadows, which are not —in this essay— the pale reflection of reality, but rather the unique and ephemeral traces of a true exercise of memory. [ABSTRACT FROM AUTHOR]

Cocoa is grown under production systems such as agroforestry and full sunlight exposition, its use depends on the agroecological regions where it is cultivated. The management of the shade canopy affects the microclimatic conditions that mainly benefit the hydric behaviour (sap flow Vs and water potential Ѱ) in the cocoa plant. It was evaluated how the modification of the shade canopy (full sunlight exposition systems SLE and agroforestry with MPAR medium and low BPAR transmitted radiation) affects the water status of cocoa trees in contrasting periods of precipitation. For the measurement of Vs and Ѱ heat sensors and stem psychrometers were installed in cocoa type CCN51 trees. An effect of the production system and monitoring season on Vs and Ѱ was found in cocoa plants. The Ѱ was higher in SLE in both seasons, but it was more accentuated in the period of minimum precipitation. A contrary behavior was found in Vs, since in minimum precipitation this variable was greater in BPAR. According to the results obtained, the management of shade canopies in cocoa crops under suboptimal climates positively affects water status. [ABSTRACT FROM AUTHOR]

In gyrotrons operating in high-order modes, during the startup process, the shadowing of the operating mode by two sidebands may take place. By "shadowing," we mean the situation when, during the voltage rise, one of the parasitic modes is excited first, and this excitation prevents the excitation of the desired mode. Then, the oscillations of the first parasitic mode, whose frequency is higher than the frequency of the desired operating mode, can be replaced by excitation of the second parasitic mode, whose frequency is lower than the operating one. As a result, the desired mode remains in the "shadow" of these parasitic modes and is never excited. This paper describes such effect in gyrotrons with diode-type electron guns. This paper consists of two parts. First, the problem is studied in a generalized approach, which means that the results are valid to gyrotrons operating at arbitrary voltages and in any modes. By using this approach, it is possible to determine the critical density of the mode spectrum, above which the shadowing occurs. This study is carried out for the cases when the interaction between modes is synchronous and when it is nonsynchronous. Second, this paper contains the analysis of a typical Megawatt-class gyrotron with a diode-type electron gun. It is studied whether the moving of this gyrotron to operating in higher-order modes will lead to the shadowing of the desired mode or other, more complicated, dynamic, and/or stochastic processes will take place. [ABSTRACT FROM AUTHOR]

In recent years, several protoplanetary discs have been observed to exhibit spirals, both in scattered light and (sub)millimetre continuum data. The HD 100453 binary star system hosts such a disc around its primary. Previous work has argued that the spirals were caused by the gravitational interaction of the secondary, which was assumed to be on a circular orbit, coplanar with the disc (meaning here the large outer disc, as opposed to the very small inner disc). However, recent observations of the CO gas emission were found incompatible with this assumption. In this paper, we run SPH simulations of the gas and dust disc for seven orbital configurations taken from astrometric fits and compute synthetic observations from their results. Comparing to high-resolution ALMA 12CO data, we find that the best agreement is obtained for an orbit with eccentricity e  = 0.32 and semimajor axis a  = 207 au, inclined by 61° relative to the disc plane. The large misalignment between the disc and orbit planes is compatible with the tidal evolution of a circumprimary disc in an eccentric, unequal-mass binary star. [ABSTRACT FROM AUTHOR]

The protoplanetary disc HD 100453 exhibits a curious combination of spirals, shadows, and a relative misalignment between the observed outer disc and inferred inner disc. This disc is accompanied by a secondary star on a bound orbit exterior to the disc. Recent observations have suggested there may be an additional low-mass companion residing within the disc inner cavity. In our companion paper, the orbit of the secondary was shown to be misaligned by 61° to the plane of the outer disc. Here, we investigate the properties of the inner companion and the origin of the misalignment between the inner and outer discs. Using numerical simulations and synthetic observations, we show that the disc structure and kinematics are consistent with a ≲ 5 MJ planet located at 15 − 20 au. We find that the disc evolution over ∼50 binary orbits (∼105 yr) is governed by differential precession and to a lesser extent, the Kozai–Lidov effect. In our proposed model, the misalignment observed between the outer and inner disc arises naturally as a result of the misaligned outer companion driving the outer disc to precess more rapidly than the inner disc. [ABSTRACT FROM AUTHOR]

In the present numerical investigation, optimum azimuth and inclination angle of building integrated photovoltaic (BIPV) system are determined due to the adverse shadow effect caused by the adjacent buildings. The factors which influence this shadow are the relative height of the building with reference to BIPV panel, plan area/orientation of the building and horizontal distance of the building from the BIPV panel. HDKR (Hay, Davies, Klucher and Reindl) anisotropic model, encompassing a shadow analysis model, is employed to determine the solar irradiation values. This model involves both shading coefficient and sky-view factor for the accurate evaluation of irradiation values due to shadow caused by the adjacent building. To determine the shading coefficient, the projection of the adjacent building is superimposed over the sun path diagram and the sky view factor is calculated by integrating the sky-trapped curve plotted for any given inclination angle of the BIPV panel Results show that the BIPV panel with optimum azimuth and inclination angle generates significantly higher irradiation as compared to the south-faced BIPV panel having an inclination angle equal to the latitude of the studied location. • Determination of solar irradiation by considering shadow caused by adjacent buildings. • Optimum azimuth and inclination angle of BIPV panels for harnessing maximum irradiation. • Optimum inclination angle value decreases with increase of shadow effect. • Optimum azimuth angle increases with increase in plan orientation of adjacent building. [ABSTRACT FROM AUTHOR]

SUMMARY: In dense canopy, a reduction in red to far‐red (R/FR) light ratio triggers shade avoidance responses (SARs) in Arabidopsis thaliana, a shade avoiding plant. Two red/far‐red (R/FR) light photoreceptors, PHYB and PHYA, were reported to be key negative regulators of the SARs. PHYB represses the SARs under normal light conditions; however, the role of PHYA in the SARs remains elusive. We set up two shade conditions: Shade and strong Shade (s‐Shade) with different R/FR ratios (0.7 and 0.1), which allowed us to observe phenotypes dominated by PHYB‐ and PHYA‐mediated pathway, respectively. By comparing the hypocotyl growth under these two conditions with time, we found PHYA was predominantly activated in the s‐Shade after prolonged shade treatment. We further showed that under s‐Shade, PHYA inhibits hypocotyl elongation partially through repressing the brassinosteroid (BR) pathway. COP1 and PIF4,5 act downstream of PHYA. After prolonged shade treatment, the nuclear localization of COP1 was reduced, while the PIF4 protein level was much lower in the s‐Shade than that in Shade. Both changes occurred in a PHYA‐dependent manner. We propose that under deep canopy, the R/FR ratio is extremely low, which promotes the nuclear accumulation of PHYA. Activated PHYA reduces COP1 nuclear speckle, which may lead to changes of downstream targets, such as PIF4,5 and HY5. Together, these proteins regulate the BR pathway through modulating BES1/BZR1 and the expression of BR biosynthesis and BR target genes. Significance Statement: Phytochrome A (PHYA) is a known negative regulator of the shade avoidance responses, but when and how it functions in shade remains elusive. We set up a strong shade condition, which allowed us to observe PHYA‐dominated responses. We found PHYA begins to inhibit shade‐induced hypocotyl elongation after prolonged strong shade treatment, which promoted PHYA nuclear localization. It subsequently inhibits shade‐induced hypocotyl elongation through repressing the BR pathway, which involves COP1 and PIF4,5. [ABSTRACT FROM AUTHOR]

The expansion of woody plants into grasslands and old fields is often ascribed to fire suppression and heavy grazing, especially by domestic livestock. However, it is also recognized that nutrient availability and interspecific competition with grasses and other woody plants play a role in certain habitats. I examined potential factors causing range- and niche expansion by the eastern redcedar Juniperus virginiana, the most widespread conifer in the eastern United States, in multifactorial experiments in a greenhouse. Historical records suggest that the eastern redcedar is a pioneer forest species, and may be replaced as the forest increases in tree density due to shading. Another possible factor that affects its distribution may be nutrient availability, which is higher in old fields and other disturbed lands than in undisturbed habitats. In its historic range, eastern redcedars are particularly abundant on limestone outcrops, often termed 'cedar barrens'. However, the higher abundance on limestone could be due to reduced interspecific competition rather than a preference for high pH substrates. I manipulated shade, fertilization, lime, and interspecific competition with a common dominant tree, the post oak Quercus stellata. In a separate experiment, I manipulated fire and grass competition. I measured growth rates (height and diameter) and above- and belowground biomass at the end of both experiments. I also measured total non-structural carbohydrates and nitrogen in these plants. Shade was the most important factor limiting the growth rates and biomass of eastern redcedars. I also found that there were significant declines in nitrogen and non-structural carbohydrates when shaded. These results are consistent with the notion that the eastern redcedar is a pioneer forest species, and that shade is the reason that these redcedars are replaced by other tree species. In the second experiment, I found that a single fire had a negative effect on young trees. There was no significant effect of competition with grass, perhaps because the competitive effect was shading by grasses and not nutrient depletion. Overall, the effects of shade were far more apparent than the effects of fire. [ABSTRACT FROM AUTHOR]

The power generated by the photovoltaic (PV) array is affected by the partial shading, caused by the neighboring object shadows, dirtiness, moving clouds, bird droppings, different orientation angles of PV modules, deposition of dust in modules, and the physical location of the PV module. Therefore, the PV systems exhibit multiple peaks of generated power and do not always track the maximum power point (MPP). Thus, to overcome these problems of multiple peaks, the PV panels are reconfigured using either electrical or physical reconfiguration methods. The main aim of this paper is to investigate the performance of magic square view (MSV) configuration of PV modules under partial shading conditions (PSCs). For validation, three kinds of PSCs patterns are considered and are then compared to the Total Cross Tied (TCT) and Sudoku (SDK) configurations: long and wide, short and narrow, and long and narrow. Overall, the obtained results show that the MSV configuration allows us to increase the power generated by the PV array by 34% and 7% under the three types of shadow studied as compared to the TCT and SDK configurations, respectively. The PV array configurations parameters are performed based on matlab/simulink software. The simulation and performance analysis of PV array configurations is performed with 81 PV modules of BP Solar Poly BP 380 modules. [ABSTRACT FROM AUTHOR]

One puzzling phenomenon in glass physics is the so-called 'shadow glass transition' which is an anomalous heat-absorbing process below the real glass transition and influences glass properties. However, it has yet to be entirely characterized, let alone fundamentally understood. Conventional calorimetry detects it in limited heating rates. Here, with the chip-based fast scanning calorimetry, we study the dynamics of the shadow glass transition over four orders of magnitude in heating rates for 24 different hyper-quenched metallic glasses. We present evidence that the shadow glass transition correlates with the secondary (β) relaxation: (i) The shadow glass transition and the β relaxation follow the same temperature–time dependence, and both merge with the primary relaxation at high temperature. (ii) The shadow glass transition is more obvious in glasses with pronounced β relaxation, and vice versa ; their magnitudes are proportional to each other. Our findings suggest that the shadow glass transition signals the thermodynamics of β relaxation in hyper-quenched metallic glasses. [ABSTRACT FROM AUTHOR]

Aim: Coffee is an important export for many developing countries, with a global annual trade value of $100 billion, but it is threatened by a warming climate. Shade trees may mitigate the effects of climate change through temperature regulation that can aid in coffee growth, slow pest reproduction, and sustain avian insectivore diversity. The impact of shade on bird diversity and microclimate on coffee farms has been studied extensively in the Neotropics, but there is a dearth of research in the Paleotropics. Location: East Africa. Methods: We created current and future regional Maxent models for avian insectivores in East Africa using Worldclim temperature data and observations from the Global Biodiversity Information Database. We then adjusted current and future bioclimatic layers based on mean differences in temperature between shade and sun coffee farms and projected the models using these adjusted layers to predict the impact of shade tree removal on climatic suitability for avian insectivores. Results: Existing Worldclim temperature layers more closely matched temperatures under shade trees than temperatures in the open. Removal of shade trees, through warmer temperatures alone, would result in reduction of avian insectivore species by over 25%, a loss equivalent to 50 years of climate change under the most optimistic emissions scenario. Under the most extreme climate scenario and removal of shade trees, insectivore richness is projected to decline from a mean of 38 to fewer than 8 avian insectivore species. Main conclusions: We found that shade trees on coffee farms already provide important cooler microclimates for avian insectivores. Future temperatures will become a regionally limiting factor for bird distribution in East Africa, which could negatively impact control of coffee pests, but the effect of climate change can be potentially mediated through planting and maintaining shade trees on coffee farms. [ABSTRACT FROM AUTHOR]

Shading of photo-voltaic panels is one of most common reason for power reduction in practical scenarios. This also causes multiple maximum peaks, thereby resulting in distortion of characteristic curves. In order to overcome the effect of shading, reconfiguration of panels is essential. In this work, the Chaotic Baker Map is proposed to reconfigure the panels in Solar Photo-Voltaic (SPV) Array. The Chaotic Baker Map, being an image processing technique, relocates the panels in SPV Array which is analogous to relocation of pixels within an image. The proposed approach augments the output power and minimizes the power loss by dispersing the concentrated shade throughout the array. The results of the proposed approach are compared to hitherto known configurations under wide range of shading spectrum for different sizes of SPV Array to support the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

An interactive effect of simultaneous shade and drought stress on drought-tolerant and drought-sensitive cultivars of soybean was studied. As drought stress intensified, the net photosynthetic rate decreased in both cultivars due to reduced leaf area, relative water content, transpiration rate, stomatal conductance, chlorophyll content, and Rubisco activity which ultimately led to yield reduction. Moreover, the chlorophyll fluorescence parameters also decreased. Interestingly, a moderate shade was found helpful in alleviating the adverse effects of drought stress, specifically in resistant cultivar N12 where seed yield improved significantly under moderate drought conditions in contrast to the cultivar C103. In summary, the effect of drought stress on soybean depended on the irradiance conditions and shade could enhance soybean drought resistance, although this resistance was cultivar dependent. With appropriate cultivar selection, a moderate shade can help optimize yield and improve the performance of drought-exposed soybean. [ABSTRACT FROM AUTHOR]

We consider rational nonlinear electrodynamics with the Lagrangian ℒ = − ℱ / (1 + 2 β ℱ) (ℱ = (1 / 4) F μ ν F μ ν is the Lorentz invariant), proposed in Ref. 63, coupled to General Relativity. The effective geometry induced by nonlinear electrodynamics corrections are found. We determine shadow's size of regular non-rotating magnetic black holes and compare them with the shadow size of the super-massive M87 ∗ black hole imaged by the Event Horizon Telescope collaboration. Assuming that the black hole mass has a pure electromagnetic nature, we obtain the black hole magnetic charge. The size of the shadow obtained is very close to the shadow size of non-regular neutral Schwarzschild black holes. As a result, we can interpret the super-massive M87 ∗ black hole as a regular (without singularities) magnetized black hole. [ABSTRACT FROM AUTHOR]

• A method to detect partial shading on a PV module without breaking maximum power point tracking (MPPT) operation is proposed. • The temperature correction formulas for the V mp and I mp are used to analyze data under various temperatures and irradiances. • A method to detect partial shading identifies whether with and without shade by analyzing data of the V mp and I mp. • The shading effects are identified from the I mp − V mp curve, which does not require I-V curve measurements. Estimation of the performance of photovoltaic (PV) module and system by using continuous monitoring data is an important issue, since the output power of PV modules is changeable, affected by the irradiance, temperature and shading effect, as well as degradation. This work proposes a method to detect partial shading on a module during its maximum power point tracking (MPPT) operation. It identifies whether there is shading on a module or not by analyzing data of the voltage at maximum power (V mp) and the current at maximum power (I mp). Recently developed temperature correction formulas for the V mp and I mp are used, in order to analyze them under various temperatures and irradiances. The experimental and simulation results show that the shading effect usually results in larger V mp than the shadeless case, compared at the same I mp. Therefore, the I mp − V mp curve shifts toward higher voltages by the shading effect, thereby enabling detection of the existence of the shading effect. A method to identify the shading effects on a PV module from the I mp – V mp curve has been clarified, which does not require I–V curve measurements. Slight partial shading such as a drop in the photocurrent of a single cell in a module by about 5–10% is possibly detected. The present results are also applicable to PV systems that include multiple modules. They are expected to be useful for accurately monitoring the performance of PV modules and systems under operation, since the V mp and I mp are measurable without breaking the MPPT operation. [ABSTRACT FROM AUTHOR]

Fine fescues, taxa within the Festuca genus, are considered some of the most shade‐tolerant cool‐season turfgrasses, but past research from field studies has been inconsistent. The objective of this research was to evaluate variation in Chewings fescue (Festuca rubra L. ssp. commutata Gaudin, CH), hard fescue (F. brevipila Tracey, HD), and strong creeping red fescue (F. rubra ssp. rubra Gaudin, ST) morphology and physiology under simulated foliar shade and full sun. Experiments were carried out using 12 CH, 13 HD, and 15 ST entries within a greenhouse with or without a photoselective filter to simulate foliar shade. The filter reduced the red to far‐red (R/FR) ratio to ∼0.66, and light intensity was reduced to 30% of full sun under shade treatment. Several parameters were assessed including height, the number of tillers, biomass, total chlorophyll, and the chlorophyll a/b ratio. In both sun and shade experiments, ST were significantly taller than the other taxa. Chewings fescue and HD had significantly more tillers than ST in sun, but both CH and ST had significantly more tillers than HD in shade. Hard fescue had the greatest biomass in sun, and the least in shade. Significantly more CH genotypes lacked shade avoidance responses (SAR) than both other taxa under shade, and a greater proportion of HD were shade intolerant. Based on this study, CH > ST > HD in terms of improved response to shade. However, variation for response to shade observed within entries indicates potential for future improvement. [ABSTRACT FROM AUTHOR]

Shadow detection and shadow removal are fundamental and challenging tasks, requiring an understanding of the global image semantics. This paper presents a novel deep neural network design for shadow detection and removal by analyzing the spatial image context in a direction-aware manner. To achieve this, we first formulate the direction-aware attention mechanism in a spatial recurrent neural network (RNN) by introducing attention weights when aggregating spatial context features in the RNN. By learning these weights through training, we can recover direction-aware spatial context (DSC) for detecting and removing shadows. This design is developed into the DSC module and embedded in a convolutional neural network (CNN) to learn the DSC features at different levels. Moreover, we design a weighted cross entropy loss to make effective the training for shadow detection and further adopt the network for shadow removal by using a euclidean loss function and formulating a color transfer function to address the color and luminosity inconsistencies in the training pairs. We employed two shadow detection benchmark datasets and two shadow removal benchmark datasets, and performed various experiments to evaluate our method. Experimental results show that our method performs favorably against the state-of-the-art methods for both shadow detection and shadow removal. [ABSTRACT FROM AUTHOR]

We investigate a procedure for determining the shadow cone of the Earth in the course of the motion of a satellite in the ecliptic plane. The average time spent by the satellite in the Area of the Earth's shadow is estimated depending on the orbit parameters in the outer sphere of the Earth's gravitational influence. The obtained estimate of the average time spent by the satellite in the shadow allows us not to take the shadow into account in the qualitative analysis of satellite motion. The results obtained for a conical shape of the shadow are compared with the results obtained for a cylindrical shape, and a choice is made in favor of the conical one. [ABSTRACT FROM AUTHOR]

Long‐term studies of wild animals provide the opportunity to investigate how phenotypic plasticity is used to cope with environmental fluctuations and how the relationships between phenotypes and fitness can be dependent upon the ecological context.Many previous studies have only investigated life‐history plasticity in response to changes in temperature, yet wild animals often experience multiple environmental fluctuations simultaneously. This requires field experiments to decouple which ecological factor induces plasticity in fitness‐relevant traits to better understand their population‐level responses to those environmental fluctuations.For the past 32 years, we have conducted a long‐term integrative study of individually marked North American red squirrels Tamiasciurus hudsonicus Erxleben in the Yukon, Canada. We have used multi‐year field experiments to examine the physiological and life‐history responses of individual red squirrels to fluctuations in food abundance and conspecific density.Our long‐term observational study and field experiments show that squirrels can anticipate increases in food availability and density, thereby decoupling the usual pattern where animals respond to, rather than anticipate, an ecological change.As in many other study systems, ecological factors that can induce plasticity (such as food and density) covary. However, our field experiments that manipulate food availability and social cues of density (frequency of territorial vocalizations) indicate that increases in social (acoustic) cues of density in the absence of additional food can induce similar life‐history plasticity, as does experimental food supplementation.Changes in the levels of metabolic hormones (glucocorticoids) in response to variation in food and density are one mechanism that seems to induce this adaptive life‐history plasticity.Although we have not yet investigated the energetic response of squirrels to elevated density or its association with life‐history plasticity, energetics research in red squirrels has overturned several standard pillars of knowledge in physiological ecology.We show how a tractable model species combined with integrative studies can reveal how animals cope with resource fluctuations through life‐history plasticity. [ABSTRACT FROM AUTHOR]