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This review of the world's literature documenting cervical spine injuries attempts to determine common factors regarding patient characteristics, environment, injury mechanisms, and pathology. The policy statements and safety guidelines of both the American Academy of Pediatrics and athletic administrative bodies are reviewed in order to evaluate what effect, if any, these policies and guidelines have had on documented injuries. On the basis of this review, it is believed that the AAP was ill-advised in altering its position on the use of trampolines. The opinion is presented that both the trampoline and minitrampoline are dangerous devices when used in the best of circumstances, and their use has no place in recreational, educational, or competitive gymnastics.
Trampoline gymnastics involves extreme human poses and uncommon viewpoints, on which state-of-the art pose estimation models tend to under-perform. We demonstrate that this problem can be addressed by fine-tuning a pose estimation model on a dataset of synthetic trampoline poses (STP). STP is generated from motion capture recordings of trampoline routines. We develop a pipeline to fit noisy motion capture data to a parametric human model, then generate multiview realistic images. We use this data to fine-tune a ViTPose model, and test it on real multi-view trampoline images. The resulting model exhibits accuracy improvements in 2D which translates to improved 3D triangulation. In 2D, we obtain state-of-the-art results on such challenging data, bridging the performance gap between common and extreme poses. In 3D, we reduce the MPJPE by 12.5 mm with our best model, which represents an improvement of 19.6% compared to the pretrained ViTPose model.
Levitated systems and high-$Q$ membrane nanomechanical resonators have achieved exceptional sensitivity in precision sensing, but functionalizing such resonators for practical applications without degrading their low dissipation remains challenging. Here, we combine diamagnetic levitation with a high-$Q$ nanomechanical resonator to realize a high-precision magnetometer for sensing weak oscillating magnetic fields. A macroscopic diamagnetically levitated graphite plate acts as a free-floating proof mass that couples strongly to magnetic fields, converting them into mechanical motion that is resonantly amplified by a low-dissipation nano-trampoline resonator. Operating at room temperature and without magnetic shielding, we achieve a peak magnetic-field sensitivity of $4.5\, \mathrm{pT}/\sqrt{\mathrm{Hz}}$ using a resonator with a mechanical quality factor of $Q=6\times10^{6}$ at $443\, \mathrm{kHz}$. The system sensitivity is limited by thermomechanical noise. With further improvements in mechanical $Q$, this hybrid levitated platform offers a pathway toward femtotesla-level AC magnetic-field sensing, establishing diamagnetically levitated nanomechanical resonators as a new class of
We analyze continuous Hopfield associative memories augmented by additional, rapid short-term associative synaptic plasticity. Through the cavity method, we determine the boundary between the retrieval and forgetting, or spin-glass phase, of the network as a function of the fraction of stored memories and the neuronal gain. We find that short-term synaptic plasticity yields marginal improvements in critical memory capacity. However, through dynamical mean field theory, backed by extensive numerical simulations, we find that short-term synaptic plasticity has a dramatic impact on memory retrieval above the critical capacity. When short-term synaptic plasticity is turned on, the combined neuronal and synaptic dynamics descends a high-dimensional energy landscape over both neurons and synapses. The energy landscape over neurons alone is thus dynamic, and is lowered in the vicinity of recent neuronal patterns visited by the network, just like the surface of a trampoline is lowered in the vicinity of regions recently visited by a heavy ball. This trampoline-like reactivity of the neuronal energy landscape to short-term plasticity in synapses can lead to the recall of stored memories tha
Micro-electro-mechanical resonators employing a magnetic element have been proposed for magnetic field sensing applications, but the integration of magnetic materials with standard semiconductor compounds is challenging and requires complex fabrication protocols. We present a different approach relying on (La0.7,Sr0.3)MnO3 (LSMO), an oxide compound that works both as structural element for the resonator and functional magnetic layer. Suspended trampolines are realized in a single step process from LSMO thin films and show quality factor up to 60k and fQ products reaching 10$^{10}$ Hz. Their magnetic properties are probed by a SQUID magnetometer and magnetic force microscopy, showing saturation magnetization of 240 kA/m at room temperature and in-plane magnetic domains with coercivity of 2.5 mT. Being entirely made from a magnetic material, these resonators exhibit a larger magnetic interaction volume compared to other solutions, making them ideal candidates as building blocks for high-sensitivity magnetic field sensors.
Elastic and acoustic metamaterials can sculpt dispersion of waves through resonances. In turn, resonances can give rise to negative effective properties, usually localized around the resonance frequencies, which support band gaps at subwavelength frequencies (i.e., below the Bragg-scattering limit). However, the band gaps width correlates strongly with the resonators' mass and volume, which limits their functionality in applications. Trampoline phenomena have been numerically and experimentally shown to broaden the operational frequency ranges of two-dimensional, pillar-based metamaterials through perforation. In this work, we demonstrate trampoline phenomena in lightweight and planar lattices consisting of arrays of Archimedean spirals in unit cells. Spiral-based metamaterials have been shown to support different band gap opening mechanisms, namely, Bragg-scattering, local resonances and inertia amplification. Here, we numerically analyze and experimentally realize trampoline phenomena in planar metasurfaces for different lattice tessellations. Finally, we carry out a comparative study between trampoline pillars and spirals and show that trampoline spirals outperform the pillars i
Nanoelectromechanical (NEMS) resonators are promising uncooled thermal infrared (IR) detectors to overcome existing sensitivity limits. Here, we investigated nanoelectromechanical trampoline resonators made of silicon nitride (SiN) as thermal IR detectors. Trampolines have an enhanced responsivity of more than two orders of magnitude compared to state-of-the-art SiN drums. The characterized NEMS trampoline IR detectors yield a sensitivity in terms of noise equivalent power (NEP) of 7pW/$\sqrt{Hz}$ and a thermal response time as low as 4 ms. The detector area features an impedance-matched metal thin-film absorber with a spectrally flat absorption of 50% over the entire mid-IR spectral range from 1$μm$ to 25$μm$.
Tensile-strained materials have been used to fabricate nano- and micromechanical resonators with ultra-low mechanical dissipation in the kHz to MHz frequency range. These mechanical resonators are of particular interest for force sensing applications and quantum optomechanics at room temperature. Tensile-strained crystalline materials that are compatible with epitaxial growth of heterostructures would thereby allow realizing monolithic free-space optomechanical devices, which benefit from stability, ultra-small mode volumes, and scalability. In our work, we demonstrate string- and trampoline resonators made from tensile-strained InGaP, which is a crystalline material that can be epitaxially grown on an AlGaAs heterostructure. The strain of the InGaP layer is defined via its Ga content when grown on (Al,Ga)As. In our case, we realize devices with a stress of up to 470\,MPa along the $[1\,1\,0]$ crystal direction. We characterize the mechanical properties of the suspended InGaP devices, such as anisotropic stress, yield strength, and intrinsic quality factor. We find that the latter degrades over time. We reach mechanical quality factors surpassing $10^7$ at room temperature with a $
OBJECTIVE: To describe the epidemiological features of trampoline-related injuries among children treated in an urban pediatric emergency department. DESIGN: A descriptive study of a consecutive series of patients. SETTING: The emergency department of a large, urban, academic children's hospital. PARTICIPANTS: Children treated for trampoline-related injuries from May 1, 1995, through April 30, 1997. RESULTS: Two hundred fourteen children were treated for trampoline-related injuries during the study period, representing, on average, 1 child treated approximately every 3 days. Children ranged in age from 1 to 16 years (mean [SD], 9.4 [3.6] years). The area of the body most commonly injured was a lower extremity (36.0%), followed by an upper extremity (31.8%), the head (14.5%), the trunk (9.8%), and the neck (7.9%). The most common type of injury was a soft tissue injury (51.9%), followed by fracture (34.6%) and laceration (11.7%). Several patterns of trampoline-related injury were identified. Extremity fractures were more common in the upper extremities (P=.006; relative risk [RR]=1.64; 95% confidence interval [CI], 1.16-2.31); however, soft tissue injuries were more common in the lower extremities (P=.006; RR=1.66; 95% CI, 1.16-2.38). Lacerations were associated with injury to the head region (P<.001; RR=67.9; 95% CI, 16.8-273.6) and were more common among children younger than 6 years (P=.02; RR=2.58; 95% CI, 1.24-5.34). Soft tissue injuries were more common among children 6 years of age and older (P=.01; RR=1.66; 95% CI, 1.08-2.55). Four patients (1.9%) with fractures were admitted to the hospital. The trampoline was located in the backyard in 96% (119/124) of cases. Adult supervision was present at the time of injury for 55.6% (65/117) of children, including 73.3% (22/30) of children younger than 6 years. Parents reported that they had been aware of the potential dangers of trampolines before the injury event (73% [81/111]), that their child had previously attempted a flip on a trampoline (56.9% [66/116]), that this was not the child's first injury on a trampoline (10% [12/120]), and that their child continued to use a trampoline after the current injury event (54.8% [63/115]). CONCLUSIONS: Trampoline-related injuries to children treated in the emergency department are almost exclusively associated with the use of backyard trampolines. The prevention strategies of warning labels, public education, and adult supervision are inadequate to prevent these injuries. Children should not use backyard trampolines, and the sale of trampolines for private recreational use should be halted.
We explore the prospects and benefits of combining the techniques of cavity optomechanics with efforts to image spins using magnetic resonance force microscopy (MRFM). In particular, we focus on a common mechanical resonator used in cavity optomechanics -- high-stress stoichiometric silicon nitride (Si$_3$N$_4$) membranes. We present experimental work with a trampoline membrane resonator that has a quality factor above $10^6$ and an order of magnitude lower mass than a comparable standard membrane resonators. Such high-stress resonators are on a trajectory to reach 0.1 $\rm{aN}/\sqrt{\rm{Hz}}$ force sensitivities at MHz frequencies by using techniques such as soft clamping and phononic-crystal control of acoustic radiation in combination with cryogenic cooling. We present a demonstration of force-detected electron spin resonance of an ensemble at room temperature using the trampoline resonators functionalized with a magnetic grain. We discuss prospects for combining such a resonator with an integrated Fabry-Perot cavity readout at cryogenic temperatures, and provide ideas for future impacts of membrane cavity optomechanical devices on MRFM of nuclear spins.
INTRODUCTION: The recreational use of trampolines has increased dramatically during the last 10 years. There has been a striking increase in the number of children presenting to fracture clinics with injuries associated with trampoline use. This increase in trampoline injuries has been reported in North America, but there has been a paucity of research in this area in Europe. METHODS: We prospectively recorded details of patients presenting to our institution, Our Lady's Children's Hospital, Crumlin (Dublin, Ireland), during the busy summer months of June, July, and August 2005. Details recorded included type and mechanism of injury, the mode of referral, treatment, inpatient days, outpatient visits, specific details relating to trampoline safety, and an analysis of the cost of medical care. RESULTS: There were 101 patients treated for trampoline-related injuries in 3 months from June to August 2005. This represented 1.5% of the total attendances to the emergency department. The average age was 8.5 years (range, 1.4-17.4 years). There were 55 fractures, 38 soft tissue injuries, 5 head injuries, and 5 neck injuries, with an average Pediatric Trauma Score of 11.4. Fifty seven percent (58/101) of patients were on the trampoline with at least 1 other person. Twenty patients (19.8%) were admitted to hospital requiring 71 inpatient days. Twelve patients were treated in theatre. There were 163 fracture clinic visits, 212 x-rays, and 2 magnetic resonance imaging scans. CONCLUSIONS: Trampolines are a high-risk activity with the potential for significant orthopaedic injury. In Ireland, we have recently seen a dramatic increase in pediatric trampoline-related injuries mirroring the trend in the United States during the last 10 to 15 years. We found that more than 1 individual on a trampoline is a major risk factor for injury, where the lightest person is 14 times more likely to be injured than the heavier. The lighter person also has a greater chance of being injured with smaller numbers on the trampoline. We reiterate the American Academy of Pediatrics policy statement advice that trampolines be used only in supervised training programs--never at home, in outdoor playgrounds, or in schools. The public should be made aware of the potential dangers of trampolines through public health campaigns, radio, and television.
Python bindings are a critical bridge between high-performance C++ libraries and the flexibility of Python, enabling rapid prototyping, reproducible experiments, and integration with simulation and learning frameworks in robotics research. Yet, generating bindings for large codebases is a tedious process that creates a heavy burden for a small group of maintainers. In this work, we investigate the use of Large Language Models (LLMs) to assist in generating nanobind wrappers, with human experts kept in the loop. Our workflow mirrors the structure of the C++ codebase, scaffolds empty wrapper files, and employs LLMs to fill in binding definitions. Experts then review and refine the generated code to ensure correctness, compatibility, and performance. Through a case study on a large C++ motion planning library, we document common failure modes, including mismanaging shared pointers, overloads, and trampolines, and show how in-context examples and careful prompt design improve reliability. Experiments demonstrate that the resulting bindings achieve runtime performance comparable to legacy solutions. Beyond this case study, our results provide general lessons for applying LLMs to binding
Strained membrane resonators have emerged as a promising platform for optomechanical accelerometry; however, the desired combination of low frequency and high $Q$-mass product requires a rethinking of their dissipation dilution engineering. Applying Bayesian optimization to a Si$_3$N$_4$ membrane, we discover a class of sail-like trampoline resonators in which the frequency is decreased by an order of magnitude while preserving the $Q$-mass product. We demonstrate centimeter-scale sails with kHz frequencies, $Q\sim10^7$ and $Q\times\text{mass}\sim$ 10 g. Vertically integrating a 7 kHz device with a nanoribbon, we realize a monolithic cavity optomechanical accelerometer with a room temperature thermal noise of $40\;\text{n}g_0/\sqrt{\text{Hz}}$, sufficient to resolve $μg_0/\sqrt{\text{Hz}}$ ambient vibration over a bandwidth of 4 kHz with a displacement imprecision of $10^{-14}\;\text{m}/\sqrt{\text{Hz}}$. Cryogenic arrays of sail membranes may be attractive for new physics searches and distributed quantum sensing experiments.
Accelerometers offer motion sensing capabilities across a wide range of areas, enabling navigational awareness in consumer goods and defense applications, and playing a key role in monitoring and control systems. To date, on-chip accelerometers have largely utilized a single device layer or substrate as a test mass. This constrains the test mass to the dimensions and density of the device layer or substrate, ultimately limiting the sensitivity of the device. We demonstrate a new approach which utilizes a pick-and-place bonding technique to increase the test mass of an on-chip accelerometer. By bonding a high-density platinum sphere to a nanomechanical silicon nitride trampoline membrane, we achieve a quality factor of 1900 in air with 95 mg test mass, corresponding to a thermomechanical noise limited acceleration sensitivity of $0.8\,\mathrm{n}g/\sqrt{\mathrm{Hz}}$. We optically probe the device's response to applied accelerations with increasing level of acoustic and vibration isolation, measuring a peak sensitivity of $5.5\,\mathrm{n}g/\sqrt{\mathrm{Hz}}$ at 117 Hz in air, limited by environmental vibrations. This represents the best peak sensitivity reported using a chip-integra
Thermomechanical infrared (IR) detectors have emerged as promising alternatives to traditional photon and thermoelectric sensors, offering broadband sensitivity and low noise without the need for cryogenic cooling. Despite recent advances, the field still lacks a unified framework to guide the design of these nanomechanical systems. This work addresses that gap by providing a comprehensive design guide for IR thermal detectors based on silicon nitride drumhead and trampolines. Leveraging a validated analytical model, we systematically explore how geometry, tensile stress, and optical properties influence key performance metrics such as thermal time constant, noise-equivalent power, and specific detectivity. The analysis encompasses both bare silicon nitride and structures with broadband absorber layers, revealing how different parameter regimes affect the trade-off between sensitivity and response speed. Rather than focusing on a single device architecture, this study maps out a broad design space, enabling performance prediction and optimisation for a variety of application requirements. As such, it serves not only as a reference for benchmarking existing devices but also as a pra
Inter-app communication is a mandatory and security-critical functionality of operating systems, such as Android. On the application level, Android implements this facility through Intents, which can also transfer non-primitive objects using Java's Serializable API. However, the Serializable API has a long history of deserialization vulnerabilities, specifically deserialization gadget chains. Research endeavors have been heavily directed towards the detection of deserialization gadget chains on the Java platform. Yet, there is little knowledge about the existence of gadget chains within the Android platform. We aim to close this gap by searching gadget chains in the Android SDK, Android's official development libraries, as well as frequently used third-party libraries. To handle this large dataset, we design a gadget chain detection tool optimized for soundness and efficiency. In a benchmark on the full Ysoserial dataset, it achieves similarly sound results to the state-of-the-art in significantly less time. Using our tool, we first show that the Android SDK contains almost the same trampoline gadgets as the Java Class Library. We also find that one can trigger Java native serializ
What do pickles and trampolines have in common? In this paper we show that while purchases for these products may seem innocuous, they risk revealing clues about customers' personal attributes - in this case, their race. As online retail and digital purchases become increasingly common, consumer data has become increasingly valuable, raising the risks of privacy violations and online discrimination. This work provides the first open analysis measuring these risks, using purchase histories crowdsourced from (N=4248) US Amazon.com customers and survey data on their personal attributes. With this limited sample and simple models, we demonstrate how easily consumers' personal attributes, such as health and lifestyle information, gender, age, and race, can be inferred from purchases. For example, our models achieve AUC values over 0.9 for predicting gender and over 0.8 for predicting diabetes status. To better understand the risks that highly resourced firms like Amazon, data brokers, and advertisers present to consumers, we measure how our models' predictive power scales with more data. Finally, we measure and highlight how different product categories contribute to inference risk in o
Gas pressure sensors based on nanomechanical membranes have recently demonstrated an ultra-wide ten-decade measurement range, a gas-type-independent response, and a self-calibrating operation with uncertainties of approximately $1\,\%$. The readout relied on tabletop free-space laser interferometers. Here we present a centimeter-sized, portable implementation in which a square Si$_3$N$_4$ membrane is read out via a fiber-based laser interferometer. We perform pressure measurements between $5\times10^{-5}$ and $10^{-1}$~mbar in a confined $0.7$~L volume cooled to $78$~K. Because no suitable commercial pressure sensor exists for direct cryogenic comparison, we benchmark our device against room-temperature commercial gauges connected to the cold volume through a pipe of limited conductance. The measured relationship between the two sensors is compared with models accounting for temperature- and pumping-induced pressure gradients within the measurement chamber. These models agree with the measurements to within $<10\,\%$ for helium and $<13\,\%$ for nitrogen. The achieved readout sensitivity of $S_x = 8\times10^{-14}\,\mathrm{m}/\sqrt{\mathrm{Hz}}$ theoretically enables resolving
Cyber-Physical Systems have played an essential role in our daily lives, providing critical services such as power and water, whose operability, availability, and reliability must be ensured. The C programming language, prevalent in CPS development, is crucial for system control where reliability is critical. However, it is also commonly susceptible to vulnerabilities, particularly buffer overflows. Traditional vulnerability discovery techniques often struggle with scalability and precision when applied directly to the binary code of C programs, which can thereby keep programs vulnerable. This work introduces a novel approach designed to overcome these limitations by leveraging model checking and concolic execution techniques to automatically verify security properties of a program's stack memory in binary code, trampoline techniques to perform automated repair of the issues, and crash-inducing inputs to verify if they were successfully removed. The approach constructs a Memory State Space -- MemStaCe -- from the binary program's control flow graph and simulations, provided by concolic execution, of C function calls and loop constructs. The security properties, defined in LTL, mode
Suspended micro-structures based on complex oxides relies on surface micro-machining processes such as those based on sacrificial layers. These processes prevent to physically access the microstructures from both sides, as substantial part of the substrate is not removed. In this work, we develop a bulk micromachining protocol of a commonly used substrate employed in oxide thin film deposition. We realize suspended oxide thin film devices by fabricating pass-through holes across SrTiO$_3$(100) or SrTiO$_3$(110) substrates. Careful calibration of anisotropic etching rates allows controlling the final geometry of the aperture in the substrate in a predictable way. As demonstrators of possible device geometries, we present clamped membranes and trampolines of (La,Sr)MnO$_3$, a conductive magnetic oxide, and a suspended trampoline resonator carved from the SrTiO$_3$ substrate itself. Reported protocols can be readily extended to a broad variety of other complex oxides so to extend the application of membranes technology beyond those of commercially-available silicon compounds.