Trap Arrays Research Articles

Time since fire interacts with herbivore intake rates to control herbivore habitat occupancy.

Smaller grazers consistently show greater preference for recently burned patches than larger species. Energy optimization theory posits that this pattern is driven by small- versus large-bodied herbivores seeking to maximize energy intake by choosing high-quality recently burned grasses, or high-quantity unburned grasses, respectively. We propose that if burn preference is driven by an energy-maximization mechanism, then preference should change over time as grass regrows and progresses across the optimal feeding heights of herbivores of increasing body size. To test this, we used a camera trap array in the Serengeti National Park to quantify changes in the relative preference for burned patches of seven ruminant herbivore species. We compared observed patterns to simulation results from a grass production-herbivore patch selection model. Burn preference and herbivore body size scaled negatively for 6 months after fire, but this relationship disappeared after 7 months when smaller species stopped selecting burns, and larger herbivores selected burns after 10 months, in a reversal of classic grazer succession. Simulations recreated the former but not the latter relationship, suggesting that an energy-maximization mechanism can drive allometric scaling of burn preference immediately after fire, but over longer periods, grazer-driven feedbacks are required to explain large herbivore burn preferences.

Balancing act: evaluating non-target risks of feral cat management in conservation reserves

Context Predation by feral cats continues to place substantial pressure on native Australian wildlife, contributing to significant population declines and localised extirpations of susceptible species. In Western Australia (WA), the registration of the poison bait Eradicat® provides a tool to help manage these introduced predators, but only in areas where the risk to non-target species is considered acceptable. The red-tailed phascogale (Phascogale calura), a small carnivorous marsupial now restricted to vegetation remnants in the highly fragmented agricultural zone of south-western WA (i.e. the Wheatbelt), is one species that may be vulnerable to lethal ingestion. Aim To investigate the impact of repeated Eradicat® baiting, to control feral cats, on the activity levels of the red-tailed phascogale, focusing on populations in two Wheatbelt conservation reserves. Methods We established a novel approach to monitoring red-tailed phascogales by using tree-mounted camera trap arrays in an area with feral cat management using ground-delivered Eradicat® baits, and two control zones with no feral cat management. We examined changes in activity levels (detection rate and occupancy) based on camera trap detections, before and after Eradicat® application, across two autumn and two spring baiting events. We also investigated non-target bait uptake using camera traps. Key results Although a small number of baits (7/60) was removed by red-tailed phascogales from the field of view of a camera, our results showed no overall impact of Eradicat® on their activity levels within the study area. Tree-mounted camera traps proved to be highly effective and efficient at detecting red-tailed phascogales. To maximise camera detections, the optimal time for monitoring red-tailed phascogales is during autumn, prior to male die-off. Conclusions Our results suggested that the risk posed to red-tailed phascogale populations from the repeated use of Eradicat® baits is likely to be low. Implications Integrating the application of Eradicat® to control feral cats with existing fox control in conservation reserves that support populations of red-tailed phascogales is likely to pose minimal risk to the species.

Three-dimensional isotropic imaging of live suspension cells enabled by droplet microvortices

Fast, nondestructive three-dimensional (3D) imaging of live suspension cells remains challenging without substrate treatment or fixation, precluding scalable single-cell morphometry with minimal alterations. While optical sectioning techniques achieve 3D live cell imaging, lateral versus depth resolution differences further complicate analysis. We present a scalable microfluidic method capable of 3D fluorescent isotropic imaging of live, nonadherent cells suspended inside picoliter droplets with high-speed single-cell volumetric readout (800 to 1,200 slices in 5 to 8 s) and near-diffraction limit resolution (~216 nm). The platform features a droplet trap array that leverages flow-induced droplet interfacial shear to generate intradroplet microvortices, which rotate single cells on their axis to enable optical projection tomography (OPT)-based imaging. This allows gentle (~1 mPa shear stress) observation of cells encapsulated inside nontoxic isotonic buffer droplets, facilitating scalable OPT acquisition by simultaneous spinning of hundreds of cells. We demonstrate 3D imaging of live myeloid and lymphoid cells in suspension, including K562 cells, as well as naive and activated T cells-small cells prone to movement in their suspended phenotype. Our fully suspended, orientation-independent cell morphometry, driven by isotropic imaging and spherical harmonic analysis, enabled the study of primary T cells across various immunological activation states. This approach unveiled six distinct nuclear content distributions, contrasting with conventional 2D images that typically portray spheroid and bean-like nuclear shapes associated with lymphocytes. Our arrayed-droplet OPT technology is capable of isotropic, single live-cell 3D imaging, with the potential to perform large-scale morphometry of immune cell effector function states while providing compatibility with microfluidic droplet operations.

Generating controllable optical trap arrays with a polarization-based metalense

Metalenses have been widely used in various optical systems due to their compact size, lightweight nature and high efficiency. This paper presents a novel metalense for generating multiple optical trap arrays. The proposed metalense is composed of many unit cells of half-wave plate. By changing the polarization state of the incident light, the optical trap array generated by the metalense can be controlled. To evaluate its performance, we simulate the metalense with total trap numbers of 4 and 6 respectively. The results show that the produced optical trap arrays exhibit precise positioning, uniform size, and intensity distribution. Furthermore, the arrays maintain excellent uniformity and shape integrity even when the number of optical traps is increased. Compared with the previous metalenses only produce a specific optical trap array, the designed metalense offers higher flexibility and better meets the experimental requirements of multi-trap optical tweezers. Our metalense exhibits significant potential for the integration and miniaturization of optical trap arrays, as well as other focusing optical systems.

Metasurface optical trap array for single atoms

Metasurfaces made of subwavelength silicon nanopillars provide unparalleled capacity to manipulate light, and have emerged as one of the leading platforms for developing integrated photonic devices. In this study, we report on a compact, passive approach based on planar metasurface optics to generate large optical trap arrays. The unique configuration is achieved with a meta-hologram to convert a single incident laser beam into an array of individual beams, followed up with a metalens to form multiple laser foci for single rubidium atom trapping. We experimentally demonstrate two-dimensional arrays of 5 × 5 and 25 × 25 at the wavelength of 830 nm, validating the capability and scalability of our metasurface design. Beam waists ∼1.5 µm, spacings (about 15 µm), and low trap depth variations (8%) of relevance to quantum control for an atomic array are achieved in a robust and efficient fashion. The presented work highlights a compact, stable, and scalable trap array platform well-suitable for Rydberg-state mediated quantum gate operations, which will further facilitate advances in neutral atom quantum computing.

Status assessment of a recently reintroduced eurasian lynx (Lynx lynx) population in the Palatinate Forest, South-West Germany

To reinforce Eurasian lynx populations in central Europe, 20 lynx from Slovakia and Switzerland were translocated to the Palatinate Forest between 2016 and 2020. Using a systematic camera trapping array consisting of 80 camera trapping sites in a 1,000 km² study area located in the centre of the approximately 1,800 km² Palatinate Forest, we aim to describe the status of the population in the final stages of the reintroduction project in winter and spring 2019/20 and 2020/21. We also use our data to provide a first estimate of population density of the newly established population. With an estimate of 0.52 independent individuals per 100 km², population density in the Palatinate Forest was still significantly lower than the densities of well-established reintroduced populations. The number of independent individuals detected in the study area decreased from 15 individuals in 2019/20 to 11 individuals in 2020/21, thus significantly below the number of lynx translocated. The low abundance in the Palatinate Forest can be explained by the dispersal of several individuals to the Vosges (France), which, together with the Palatinate Forest, form a continuous area of suitable lynx habitat of approximately 8,000 km². Our results may thus reflect the status of a young population that can expand over a potentially large area. Nevertheless, in light of the low population density, we strongly recommend a synchronized and harmonized transboundary monitoring program to keep track of the development of this important Franco-German lynx population. In case population density remains low, supportive measures need to be considered.

Generating dipole trap arrays based on dielectric metasurface at 808 nm

We propose to use dielectric metasurface as a novel platform to generate dipole trap arrays with high quality and efficiency. According to the specific design parameters of the dipole trap array, the modulation phase and the focusing phase are calculated respectively. Building upon this, we design a metasurface device consisting of cylindrical TiO2-based integrated-resonant unit-cells by combining the modulating phase with the focusing phase. In addition, by finely adjusting the position of the nanopillar, a good match between the theoretical phase and the transmission phase of the nanopillar can be achieved to reduce the aberration introduced by the metasurface device. We conducted simulation experiments to demonstrate several configurations of dipole trap arrays. The results indicate that the obtained dipole trap arrays are precisely positioned and have uniform intensity distribution. The spacing and quantity of the traps obtained through this method can be controlled, providing a versatile and scalable system for neutral single-atom quantum information processing and quantum simulation.

SNAPSHOT USA 2021: A third coordinated national camera trap survey of the United States.

SNAPSHOT USA is a multicontributor, long-term camera trap survey designed to survey mammals across the United States. Participants are recruited through community networks and directly through a website application (https://www.snapshot-usa.org/). The growing Snapshot dataset is useful, for example, for tracking wildlife population responses to land use, land cover, and climate changes across spatial and temporal scales. Here we present the SNAPSHOT USA 2021 dataset, the third national camera trap survey across the US. Data were collected across 109 camera trap arrays and included 1711 camera sites. The total effort equaled 71,519 camera trap nights and resulted in 172,507 sequences of animal observations. Sampling effort varied among camera trap arrays, with a minimum of 126 camera trap nights, a maximum of 3355 nights, a median 546 nights, and a mean 656 ± 431 nights. This third dataset comprises 51 camera trap arrays that were surveyed during 2019, 2020, and 2021, along with 71 camera trap arrays that were surveyed in 2020 and 2021. All raw data and accompanying metadata are stored on Wildlife Insights (https://www.wildlifeinsights.org/), and are publicly available upon acceptance of the data papers. SNAPSHOT USA aims to sample multiple ecoregions in the United States with adequate representation of each ecoregion according to its relative size. Currently, the relative density of camera trap arrays varies by an order of magnitude for the various ecoregions (0.22-5.9 arrays per 100,000 km2), emphasizing the need to increase sampling effort by further recruiting and retaining contributors. There are no copyright restrictions on these data. We request that authors cite this paper when using these data, or a subset of these data, for publication. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US Government.

Bilayer ion trap design for 2D arrays

Junctions are fundamental elements that support qubit locomotion in two-dimensional ion trap arrays and enhance connectivity in emerging trapped-ion quantum computers. In surface ion traps they have typically been implemented by shaping radio frequency (RF) electrodes in a single plane to minimize the disturbance to the pseudopotential. However, this method introduces issues related to RF lead routing that can increase power dissipation and the likelihood of voltage breakdown. Here, we propose and simulate a novel two-layer junction design incorporating two perpendicularly rotoreflected (rotated, then reflected) linear ion traps. The traps are vertically separated, and create a trapping potential between their respective planes. The orthogonal orientation of the RF electrodes of each trap relative to the other provides perpendicular axes of confinement that can be used to realize transport in two dimensions. While this design introduces manufacturing and operating challenges, as now two separate structures have to be precisely positioned relative to each other in the vertical direction and optical access from the top is obscured, it obviates the need to route RF leads below the top surface of the trap and eliminates the pseudopotential bumps that occur in typical junctions. In this paper the stability of idealized ion transfer in the new configuration is demonstrated, both by solving the Mathieu equation analytically to identify the stable regions and by numerically modeling ion dynamics. Our novel junction layout has the potential to enhance the flexibility of microfabricated ion trap control to enable large-scale trapped-ion quantum computing.

Rapid Isolation and Detection of Breast Cancer Circulating Tumor Cells Using Microfluidic Sequential Trapping Array

AbstractCirculating tumor cells (CTCs) have garnered special attention as promising cancer biomarkers. Phenotypic changes of CTCs reveal invaluable information for oncologists in disease prognosis and adjusting their treatment options. Microfluidic technology has emerged as a promising tool for CTC isolation; however, two major hurdles remain to be solved in employing them in CTC analysis. First, a rapid CTC isolation scheme is needed to allow immediate use of patient samples for point‐of‐care treatment monitoring. Second, multiplexed and streamlined CTC imaging is needed to facilitate CTC detection. Here, a microfluidic CTC sequential trapping array (STA) is proposed which addresses these hurdles enabling pipette‐based CTC isolation and simultaneous profiling of multiple CTC protein expressions. The STA device isolates CTCs based on their size difference from blood cells and increases sample processing throughput through its parallel design configuration. It successfully isolates CTC from a depleted peripheral blood mononuclear cells sample of breast cancer patients with a high recovery rate of 80% and discriminates the number and types of CTCs in breast cancer based on their disease stage. These findings will open a new avenue in clinical translation of CTC profiling technologies. It will be an example for future translational developments in CTC‐based cancer management.

Mesocarnivores vary in their spatiotemporal avoidance strategies at communications hubs of an apex carnivore.

Mesocarnivores face interspecific competition and risk intraguild predation when sharing resources with apex carnivores. Within a landscape, carnivores across trophic levels may use the same communication hubs, which provide a mix of risks (injury/death) and rewards (gaining information) for subordinate species. We predicted that mesocarnivores would employ different strategies to avoid apex carnivores at shared communication hubs, depending on their trophic position. To test our prediction, we examined how different subordinate carnivore species in the Santa Cruz Mountains of California, USA, manage spatial overlap with pumas (Puma concolor), both at communication hubs and across a landscape-level camera trap array. We estimated species-specific occurrence, visitation rates, temporal overlap, and Avoidance-Attraction Ratios from camera traps and tested for differences between the two types of sites. We found that mesocarnivores generally avoided pumas at communication hubs, and this became more pronounced when pumas scent-marked during their most recent visit. Coyotes (Canis latrans), the pumas' closest subordinate competitor in our system, exhibited the strongest avoidance at communication hubs. Gray foxes (Urocyon cinereoargenteus) avoided pumas the least, which may suggest possible benefits from pumas suppressing coyotes. Overall, mesocarnivores exhibited various spatiotemporal avoidance strategies at communication hubs rather than outright avoidance, likely because they benefit from information gained while 'eavesdropping' on puma activity. Variability in avoidance strategies may be due to differential predation risks, as apex carnivores often interact more aggressively with their closest competitors. Combined, our results show how apex carnivores trigger complex species interactions across the entire carnivore guild and how trophic position determines behavioral responses and subsequent space use of subordinate mesocarnivores across the landscape.

A versatile, semi-automated image analysis workflow for time-lapse camera trap image classification

Camera traps are a powerful, practical, and non-invasive method used widely to monitor animal communities and evaluate management actions. However, camera trap arrays can generate thousands to millions of images that require significant time and effort to review. Computer vision has emerged as a tool to accelerate this image review process. We propose a multi-step, semi-automated workflow which takes advantage of site-specific and generalizable models to improve detections and consists of (1) automatically identifying and removing low-quality images in parallel with classification into animals, humans, vehicles, and empty, (2) automatically cropping objects from images and classifying them (rock, bait, empty, and species), and (3) manually inspecting a subset of images. We trained and evaluated this approach using 548,627 images from 46 cameras in two regions of the Arctic: “Finnmark” (Finnmark County, Norway) and “Yamal” (Yamalo-Nenets Autonomous District, Russia). The automated steps yield image classification accuracies of 92% and 90% for the Finnmark and Yamal sets, respectively, reducing the number of images that required manual inspection to 9.2% of the Finnmark set and 3.9% of the Yamal set. The amount of time invested in developing models would be offset by the time saved from automation after 960 thousand images have been processed. Researchers can modify this multi-step process to develop their own site-specific models and meet other needs for monitoring and surveying wildlife, balancing the acceptable levels of false negatives and positives.

Geographic differences in body size distributions underlie food web connectance of tropical forest mammals

Understanding variation in food web structure over large spatial scales is an emerging research agenda in food web ecology. The density of predator–prey links in a food web (i.e., connectance) is a key measure of network complexity that describes the mean proportional dietary breadth of species within a food web. Connectance is a critical component of food web robustness to species loss: food webs with lower connectance have been shown to be more susceptible to secondary extinctions. Identifying geographic variation in food web connectance and its drivers may provide insight into community robustness to species loss. We investigated the food web connectance of ground-dwelling tropical forest mammal communities in multiple biogeographic regions to test for differences among regions in food web connectance and to test three potential drivers: primary productivity, contemporary anthropogenic pressure, and variation in mammal body mass distributions reflective of historical extinctions. Mammal communities from fifteen protected forests throughout the Neo-, Afro-, and Asian tropics were identified from systematic camera trap arrays. Predator–prey interaction data were collected from published literature, and we calculated connectance for each community as the number of observed predator–prey links relative to the number of possible predator–prey links. We used generalized linear models to test for differences among regions and to identify the site level characteristics that best predicted connectance. We found that mammal food web connectance varied significantly among continents and that body size range was the only significant predictor. More possible predator–prey links were observed in communities with smaller ranges in body size and therefore sites with smaller body size ranges had higher mean proportional dietary breadth. Specifically, mammal communities in the Neotropics and in Madagascar had significantly higher connectance than mammal communities in Africa. This geographic variation in contemporary mammalian food web structure may be the product of historical extinctions in the Late Quaternary, which led to greater losses of large-bodied species in the Neotropics and Madagascar thus contributing to higher average proportional dietary breadth among the remaining smaller bodied species in these regions.

Probing T-cell activation in nanoliter tumor co-cultures using membrane displacement trap arrays.

Immune responses against cancer are inherently stochastic, with small numbers of individual T cells within a larger ensemble of lymphocytes initiating the molecular cascades that lead to tumor cytotoxicity. A potential source of this intra-tumor variability is the differential ability of immune cells to respond to tumor cells. Classical microwell co-cultures of T cells and tumor cells are inadequate for reliably culturing and analyzing low cell numbers needed to probe this variability, and have failed in recapitulating the heterogeneous small domains observed in tumors. Here we leverage a membrane displacement trap array technology that overcomes limitations of conventional microwell plates for immunodynamic studies. The microfluidic platform supports on-demand formation of dense nanowell cultures under continuous perfusion reflecting the tumor microenvironment, with real-time monitoring of T cell proliferation and activation within each nanowell. The system enables selective ejection of cells for profiling by fluorescence activated cell sorting, allowing observed on-chip variability in immune response to be correlated with off-chip quantification of T cell activation. The technology offers new potential for probing the molecular origins of T cell heterogeneity and identifying specific cell phenotypes responsible for initiating and propagating immune cascades within tumors. Insight Box Variability in T cell activation plays a critical role in the immune response against cancer. New tools are needed to unravel the mechanisms that drive successful anti-tumor immune response, and to support the development of novel immunotherapies utilizing rare T cell phenotypes that promote effective immune surveillance. To this end, we present a microfluidic cell culture platform capable of probing differential T cell activation in an array of nanoliter-scale wells coupled with off-chip cell analysis, enabling a high resolution view of variable immune response within tumor / T cell co-cultures containing cell ensembles orders of magnitude smaller than conventional well plate studies.

Experimental realization of one-dimensional single-atom array based on microscale optical dipole traps

Neutral atom array serves as a crucial experimental platform for studying many-body physics, quantum computing, and quantum simulation. In this work, we describe in detail the experimental process of preparing a one-dimensional homogeneous single atom array containing 40 Cs atoms, including the dipole trap array generation device, atomic array fluorescence imaging, and the uniformity optimization of the dipole trap array. The beam waist of the dipole trap is about 1.8 μm, and the spatial resolution of the imaging system is higher than 1.55 μm. The non-uniformity of dipole trap array is mainly caused by the intermodulation effect of multi-tone signal during amplification. The uniformity of the dipole trap array is optimized to 2% (Fig. (a)) by measuring the fluctuations of the dipole trap intensity and the light shift of trapped atom, and providing feedback to adjust the phase and amplitude applied to the multi-tone RF signal on acousto-optic deflectors. Furthermore, the uniformity of oscillation frequency, loading rate, and lifetime for trapped atom in the dipole trap array are measured. These results show that oscillation frequency has a uniformity within 2% (Fig. (b)); mean loading rate is around 58% with a uniformity within 3%; and mean lifetime of single atom in dark trap is around 6(1) s with a uniformity within 8%.

Microfluidic sperm trap array for single-cell flagellar analysis with unrestricted 2D flagellar movement.

Sperm capture techniques that immobilize sperm to halt their motility are essential for the long-term analysis of individual sperm. These techniques are beneficial in assisted reproductive technologies such as intracytoplasmic sperm injection (ICSI) by allowing selective screening of sperm. However, there is a notable lack of high-throughput and non-destructive sperm capture methods that allow the flagellum to beat freely, which is crucial for accurately reflecting the behavior of unfettered, freely swimming sperm. To bridge this gap, we introduce a novel microfluidic device specifically engineered to capture sperm without restricting flagellar motion. The design utilizes sperm's innate boundary-following behavior in both 3D and 2D environments to direct them into a capture zone. Once captured, the sperm head is restrained while the flagellum remains free to exhibit natural beating patterns. Utilizing this device, we explore the effects of hyperactivating agents, temperature, and their combined influence on the dynamics of bovine sperm flagella. The unrestricted flagellar motion offered by our device yields two prominent advantages: it mirrors the flagellar behavior of free-swimming sperm, ensuring research findings are consistent with natural sperm activity, and it prevents imaging overlap between the flagellum and the capture structures, simplifying the automation of flagellar tracking and analysis. This technological advancement facilitates the collection of waveform parameters along the entire flagellum, addressing inconsistencies that have arisen in previous research due to differing measurement sites, and enabling precise extraction of sperm behavioral properties.

Confinement-enhanced microalgal individuals biosensing for digital atrazine assay

Microalgal sensors are widely recognized for their high sensitivity, accessibility, and low cost. However, the current dilemma of motion-induced spatial phase changes and concentration-related multiple scattering interferes with induced test instability and limited sensitivity, which has hindered their practical applications. Here, a differentiated strategy, named confinement-enhanced microalgal biosensing (C-EMB), is developed and proposed to pave the way. The in-situ printed microgel trap is designed to confine Chlamydomonas reinhardtii individuals, stabilizing their spatial phase. The microgel trap arrays are introduced to eliminate the multiple scattering of microalgae, breaking the existing effective concentration in traditional microalgal sensing and enabling sensitive assays. The integration with lab-on-a-chip technology and a developed digital imaging algorithm empower portable and automated detection. With this system, a microalgae analyzer is developed for atrazine detection, featuring a linear range of 0.04–100 μg/L. We assess the system's performance through practical atrazine assays on commercial food, using a double-blind test against a standard instrument. Our results demonstrate the good accuracy and test stability of this system with the mean bias atrazine detection in corn and sugarcane juice samples (SD) were 1.661 μg/L (3.122 μg/L) and 3.144 μg/L (4.125 μg/L), respectively. This method provides a new paradigm of microalgal sensors and should advance the further applications of microalgal sensors in commercial and practical settings.

Robust acoustic trapping and perturbation of single-cell microswimmers illuminate three-dimensional swimming and ciliary coordination

We report a label-free acoustic microfluidic method to confine single, cilia-driven swimming cells in space without limiting their rotational degrees of freedom. Our platform integrates a surface acoustic wave (SAW) actuator and bulk acoustic wave (BAW) trapping array to enable multiplexed analysis with high spatial resolution and trapping forces that are strong enough to hold individual microswimmers. The hybrid BAW/SAW acoustic tweezers employ high-efficiency mode conversion to achieve submicron image resolution while compensating for parasitic system losses to immersion oil in contact with the microfluidic chip. We use the platform to quantify cilia and cell body motion for wildtype biciliate cells, investigating effects of environmental variables like temperature and viscosity on ciliary beating, synchronization, and three-dimensional helical swimming. We confirm and expand upon the existing understanding of these phenomena, for example determining that increasing viscosity promotes asynchronous beating. Motile cilia are subcellular organelles that propel microorganisms or direct fluid and particulate flow. Thus, cilia are critical to cell survival and human health. The unicellular alga Chlamydomonas reinhardtii is widely used to investigate the mechanisms underlying ciliary beating and coordination. However, freely swimming cells are difficult to image with sufficient resolution to capture cilia motion, necessitating that the cell body be held during experiments. Acoustic confinement is a compelling alternative to use of a micropipette, or to magnetic, electrical, and optical trapping that may modify the cells and affect their behavior. Beyond establishing our approach to studying microswimmers, we demonstrate a unique ability to mechanically perturb cells via rapid acoustic positioning.

Point singularity array with metasurfaces

Phase singularities are loci of darkness surrounded by monochromatic light in a scalar field, with applications in optical trapping, super-resolution imaging, and structured light-matter interactions. Although 1D singular structures, like optical vortices, are common due to their robust topological properties, uncommon 0D (point) and 2D (sheet) singularities can be generated by wavefront-shaping devices like metasurfaces. With the design flexibility of metasurfaces, we deterministically position ten identical point singularities using a single illumination source. The phasefront is inverse-designed using phase-gradient maximization with an automatically-differentiable propagator and produces tight longitudinal intensity confinement. The array is experimentally realized with a TiO2 metasurface. One possible application is blue-detuned neutral atom trap arrays, for which this field would enforce 3D confinement and a potential depth around 0.22 mK per watt of incident laser power. We show that metasurface-enabled point singularity engineering may significantly simplify and miniaturize the optical architecture for super-resolution microscopes and dark traps.

Puma predation on Magellanic penguins: An unexpected terrestrial-marine linkage in Patagonia

The global loss of top predators has led to widespread changes in food webs. In Patagonia, it is hypothesized that local extirpations of terrestrial predators, including the puma (Puma concolor), has led to the expansion of Magellanic penguin (Spheniscus magellanicus) colonies across the Atlantic coast of Argentina. Interestingly, more recent wildlife conservation efforts in the region have led to an unexpected trophic link between pumas and penguins. Here, we used a camera trap array to assess this novel predator-prey relationship between pumas and penguins in Monte León National Park (MLNP) over a three-month period. Pumas were detected 12.5 times more than any other mammalian predator and were detected on 95% of the days during our study period. We also observed 28 individual events of pumas preying upon penguins. Our work demonstrates a strong linkage between the marine and terrestrial ecosystem at MLNP. Puma predation of penguins may have widespread ecological implications including effects on puma and penguin abundance, changes in puma social behavior, and interspecific competition among other prey items and carnivores in the park. We propose hypotheses and questions to investigate these potential outcomes.