Minimal Resolution Research Articles

Sub-micro-g resolution test of accelerometers based on tilt dynamic modulation in gravity field

Abstract Strategic-grade accelerometers play a pivotal role in various application fields and fundamental research. As the performance of accelerometers are improving rapidly, the requirements for test method have been raised. However, due to the influence of environmental noise, the test facility for accelerometers, especially when the resolution reaches sub-μg level, remains a challenge.
To address this limitation, this study introduces a resolution test facility based on tilt modulation in gravity field, driven by piezoelectric ceramic stacks. The input acceleration ranges from 30ng to 10μg, and the frequency is adjustable from 0.01Hz to 20Hz. Since the input acceleration oscillates at certain frequency, modulation & demodulation technology enables us to extract ultra weak signal out of relatively noisy background. With this facility, we test the resolution of commercial strong motion accelerograph, quartz flexure accelerometers, and homemade accelerometer based on levitated optomechanics, proving the reliability of this method. Our advancement in test method lay solid foundation for strategic-grade accelerometers, not only provides a minimal resolution test solution in the ng~μg range, but also provides a possible scheme of evaluating dynamic response characteristic with an ultra-low acceleration input in a considerable frequency range.

Spatial mapping of greenhouse gases using a UAV monitoring platform over a megacity in China

Urban environments are recognized as main anthropogenic contributors to greenhouse gas (GHG) emissions, characterized by unevenly distributed emission sources over the urban environments. However, spatial GHG distributions in urban regions are typically obtained through monitoring at only a limited number of locations, or through model studies, which can lead to incomplete insights into the heterogeneity in the spatial distribution of GHGs. To address such information gap and to evaluate the spatial representation of a planned GHG monitoring network, a custom-developed atmospheric sampler was deployed on a UAV platform in this study to map the CO2 and CH4 mixing ratios in the atmosphere over Zhengzhou in central China, a megacity of nearly 13 million people. The aerial survey was conducted along the main roads at an altitude of 150 m above ground, covering a total distance of 170 km from the city center to the suburbs. The spatial distributions of CO2 and CH4 mixing ratios in Zhengzhou exhibited distinct heterogeneities, with average mixing ratios of CO2 and CH4 at 439.2 ± 10.8 ppm and 2.12 ± 0.04 ppm, respectively. A spatial autocorrelation analysis was performed on the measured GHG mixing ratios across the city, revealing a spatial correlation range of approximately 2 km for both CO2 and CH4 in the urban area. Such a spatial autocorrelation distance suggests that the urban GHG monitoring network designed for emission inversion purposes need to have a spatial resolution of 4 km to characterize the spatial heterogeneities in the GHGs. This UAV-based measurement approach demonstrates its capability to monitor GHG mixing ratios across urban landscapes, providing valuable insights for GHG monitoring network design.

On the bottleneck stability of rank decompositions of multi-parameter persistence modules

A significant part of modern topological data analysis is concerned with the design and study of algebraic invariants of poset representations—often referred to as persistence modules. One such invariant is the minimal rank decomposition, which encodes the ranks of all the structure morphisms of the persistence module by a single ordered pair of rectangle-decomposable modules, interpreted as a signed barcode. This signed barcode generalizes the concept of persistence barcode from one-parameter persistence to any number of parameters, raising the question of its bottleneck stability. We show in this paper that the minimal rank decomposition is not stable under the natural notion of signed bottleneck matching between signed barcodes. We remedy this by turning our focus to the rank exact decomposition, a related signed barcode induced by the minimal projective resolution of the module relative to the so-called rank exact structure, which we prove to be bottleneck stable under signed matchings. As part of our proof, we obtain two intermediate results of independent interest: we compute the global dimension of the rank exact structure on the category of finitely presentable multi-parameter persistence modules, and we prove a bottleneck stability result for hook-decomposable modules. We also give a bound for the size of the rank exact decomposition that is polynomial in the size of the usual minimal projective resolution, we prove a universality result for the dissimilarity function induced by the notion of signed matching, and we compute, in the two-parameter case, the global dimension of a different exact structure related to the upsets of the indexing poset. This set of results combines concepts from topological data analysis and from the representation theory of posets, and we believe is relevant to both areas.

Information Bottleneck Approach for Markov Model Construction.

Markov state models (MSMs) have proven valuable in studying the dynamics of protein conformational changes via statistical analysis of molecular dynamics simulations. In MSMs, the complex configuration space is coarse-grained into conformational states, with dynamics modeled by a series of Markovian transitions among these states at discrete lag times. Constructing the Markovian model at a specific lag time necessitates defining states that circumvent significant internal energy barriers, enabling internal dynamics relaxation within the lag time. This process effectively coarse-grains time and space, integrating out rapid motions within metastable states. Thus, MSMs possess a multiresolution nature, where the granularity of states can be adjusted according to the time-resolution, offering flexibility in capturing system dynamics. This work introduces a continuous embedding approach for molecular conformations using the state predictive information bottleneck (SPIB), a framework that unifies dimensionality reduction and state space partitioning via a continuous, machine learned basis set. Without explicit optimization of the VAMP-based scores, SPIB demonstrates state-of-the-art performance in identifying slow dynamical processes and constructing predictive multiresolution Markovian models. Through applications to well-validated mini-proteins, SPIB showcases unique advantages compared to competing methods. It autonomously and self-consistently adjusts the number of metastable states based on a specified minimal time resolution, eliminating the need for manual tuning. While maintaining efficacy in dynamical properties, SPIB excels in accurately distinguishing metastable states and capturing numerous well-populated macrostates. This contrasts with existing VAMP-based methods, which often emphasize slow dynamics at the expense of incorporating numerous sparsely populated states. Furthermore, SPIB's ability to learn a low-dimensional continuous embedding of the underlying MSMs enhances the interpretation of dynamic pathways. With these benefits, we propose SPIB as an easy-to-implement methodology for end-to-end MSM construction.

Influence of the spatial resolution of Digital Elevation Models on water-balance estimations in temporary shallow lakes

Many shallow lakes are strongly degraded and their hydroecological functioning has been altered. At the same time, their rate of disappearance is remarkably high compared to other ecosystem types. Moreover, due to their relatively small size and shallow depth these lakes are highly sensitive to meteorological variability, making them highly vulnerable to climate change. The accurate estimation of their water balance is key to identifying proper management strategies. To carefully model the water balance, it is necessary to use a Digital Elevation Model (DEM) of a high-enough spatial resolution to understand the bathymetric relationships of the basin; however, it is not always possible to generate DEMs with field data. Even when DEMs are available, it is still unclear what spatial resolution is adequate to obtain an accurate water balance in shallow lakes. The aim of this work was to analyze the influence that bathymetries from different DEMs may have on shallow lake-water-balance estimations, using Lake Alcahozo (central Spain) as a case study. To do this, hydrological balances were developed with Lidar-derived DEMs with different spatial resolutions, and these balances were compared with one developed from bathymetric field data. The hydrological models obtained were calibrated with limnimetric measurements and validated with estimates of flooded areas calculated via remote-sensing imagery. The main results showed that, to a certain extent, the different resolutions of bathymetries do not have a strong influence on the result of water-balance estimations: DEMs up to a spatial resolution of 50 m (a pixel size representing 0.3 % of the basin area) have shown similar goodness-of-fit in the modeling of the hydrological balances in our case study. Therefore, depending on the objective of the study, Lidar data with different spatial resolutions can be used, up to a minimal resolution that should be determined on a case-by-case basis.

The Effect of Different System Parameters on the Movement of Microbial Cells Using Light-Induced Dielectrophoresis.

The manipulation of single particles remains a topic of interest with many applications. Here we characterize the impact of selected parameters on the motion of single particles thanks to dielectrophoresis (DEP) induced by visible light, in a technique called Light-induced Dielectrophoresis, or LiDEP, also known as optoelectronic tweezers, optically induced DEP, and image-based DEP. Baker's yeast and Candida cells are exposed to an electric field gradient enabled by shining a photoconductive material with a specific pattern of visible light, and their response is measured in terms of the average cell velocity towards the gradient. The impact on cell velocity when varying the shape and color of the light pattern, as well as the distance from the cell to the pattern, is presented. The experimental setup featured a commercial light projector featuring digital light processing (DLP) technology but mechanically modified to accommodate a 40× microscope objective lens. The minimal resolution achieved on the light pattern was 8 µm. Experimental results show the capability for single cell manipulation and the possibility of using different shapes, colors, and distances to determine the average cell velocity.

Minimal resolutions of threefolds

<abstract><p>We describe the resolution of singularities of a threefold which has minimal Picard number. We describe the relation between this minimal resolution and an arbitrary resolution of singularities.</p></abstract>

Minimal invasive resolution in pancreatic necrosis: experience in an Ecuadorian Medical Center

Minimal invasive resolution in pancreatic necrosis: experience in an Ecuadorian Medical Center

Multipath optical thermometry realized by electronic levels and Stark sublevels of Er3+

High-performance optical thermometer that can operate in the long-wavelength range of the second near infrared (1500 nm–1700 nm, NIR-IIb) biological window is in desperate need for bio-medical treatment. In this paper, a multipath temperature sensor Y3NbO7: Yb3+/Er3+ with pure cubic phase is synthesized by the high temperature solid state method. Under the excitation of 980 nm wavelength, efficient green upconversion emission attributed to thermally coupled Er3+: 2H11/2/4S3/2 levels are found, through which an excellent temperature sensing properties are realized with the maximal absolute and relative sensitivity of approximately 0.54 % K−1 and 1.37 % K−1 as well as the minimal temperature resolution of about 0.024 K. More importantly, the sample exhibits remarkable temperature detection capacity in deep tissues, which is implemented by the thermally coupled Stark sublevels of Er3+: 4I13/2 locating just in the NIR-IIb sub-window. Thanks to this appropriate response wavelength range, the maximal penetration depth of the NIR-IIb optical thermometer in the biological tissues can reach up to 8 mm. All the findings indicate that the present sample is a supernormal multipath thermometric probe with detectability in the deep biological tissues.

The Eliahou-Kervaire resolution over a skew polynomial ring

In a 1987 paper, Eliahou and Kervaire constructed a minimal resolution of a class of monomial ideals in a polynomial ring, called stable ideals. As a consequence of their construction they deduced several homological properties of stable ideals. Furthermore they showed that this resolution admits an associative, graded commutative product that satisfies the Leibniz rule. In this paper we show that their construction can be extended to stable ideals in skew polynomial rings. As a consequence we show that the homological properties of stable ideals proved by Eliahou and Kervaire hold also for stable ideals in skew polynomial rings.

RETRACTED: Résultats à long terme de la kératoprothèse de Boston de type I au Canada

To evaluate long-term visual outcomes of Boston type I keratoprosthesis (KPro) surgery and identify risk factors for visual failure. Single surgeon retrospective cohort study including 85 eyes of 74 patients who underwent KPro implantation to treat severe ocular surface disease, including limbal stem cell deficiency, postinfectious keratitis, aniridia and chemical burns. Procedures were performed at the Centre hospitalier de l'Université de Montréal from October 2008 to May 2012. All patients with at least 5 years of follow-up were included in the analysis, including eyes with repeated KPro. Main outcome measures were visual acuity (VA), visual failure, defined as a sustained VA worse than the preoperative VA, postoperative complications, and device retention. Mean follow-up was 7.2±1.3 years (±SD). Mean VA was 2.1±0.7 (logarithm of minimal angle resolution) preoperatively and 1.9±1.2 at last follow-up. In total, 2.4% of patients had VA better than 20/200 preoperatively vs. 36.5% at last follow-up. Maintenance of improved postoperative VA was seen in 61.8% of eyes at 7 years. Preoperative factors associated with visual failure were known history of glaucoma (HR=2.7 [1.2 to 5.9], P=0.02) and Stevens-Johnson syndrome (HR=7.3 [2.5 to 21.4], P<0.01). Cumulative 8-year complication rates were 38.8% retroprosthetic membrane formation, 25.9% hypotony, 23.5% new onset glaucoma, 17.6% retinal detachment, 8.2% device extrusion and 5.9% endophthalmitis. The majority (91.8%) of eyes retained the device 8 years after implantation. Nearly two-thirds of patients exhibited improved VA 7 years after KPro implantation. Preoperative risk factors for visual failure were known glaucoma and Stevens-Johnson syndrome.

Instrumental Effects of Lyα Properties in CLASSY and Implication for HETDEX and JWST

In this work, we quantify the effects of spectral resolution (R) on the measured Lyα properties and determine the robustness of Lyα trends measured with different spectrographs. We select 9 galaxies with diverse Lyα properties from the COS Legacy Archive Spectroscopic SurveY and measure the equivalent width and peak velocities of their Lyα profiles from their high-resolution spectra (R ∼ 4225–15000). We downgrade these spectra to several lower resolutions (R ∼ 800–3500) and re-measure the Lyα properties. Using these values, we derive the systematic errors and investigate the robustness of Lyα properties as a function of spectral resolution. We find that equivalent width can be robustly measured at low R. However, the minimal spectral resolution required to obtain robust measurements of the Lyα peak velocities is R ≳ 2600 (Δv = 115 km s−1).

Minimal Required Resolution to Capture the 3D Shape of the Human Back-A Practical Approach.

Adolescent idiopathic scoliosis (AIS) is a prevalent musculoskeletal disorder that causes abnormal spinal deformities. The early screening of children and adolescents is crucial to identify and prevent the further progression of AIS. In clinical examinations, scoliometers are often used to noninvasively estimate the primary Cobb angle, and optical 3D scanning systems have also emerged as alternative noninvasive approaches for this purpose. The recent advances in low-cost 3D scanners have led to their use in several studies to estimate the primary Cobb angle or even internal spinal alignment. However, none of these studies demonstrate whether such a low-cost scanner satisfies the minimal requirements for capturing the relevant deformities of the human back. To practically quantify the minimal required spatial resolution and camera resolution to capture the geometry and shape of the deformities of the human back, we used multiple 3D scanning methodologies and systems. The results from an evaluation of 30 captures of AIS patients and 76 captures of healthy subjects showed that the minimal required spatial resolution is between 2 mm and 5 mm, depending on the chosen error tolerance. Therefore, a minimal camera resolution of 640 × 480 pixels is recommended for use in future studies.

Resolution Limits of Non-Adaptive 20 Questions Search for a Moving Target

Using the 20 questions estimation framework with query-dependent noise, we study non-adaptive search strategies for a moving target over the unit cube with unknown initial location and velocities under a piecewise constant velocity model. In this search problem, there is an oracle who knows the instantaneous location of the target at any time. Our task is to query the oracle as few times as possible to accurately estimate the location of the target at any specified time. We first study the case where the oracle’s answer to each query is corrupted by discrete noise and then generalize our results to the case of additive white Gaussian noise. In our formulation, the performance criterion is the resolution, which is defined as the maximal L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> distance between the true locations and estimated locations. We characterize the minimal resolution of an optimal non-adaptive query procedure with a finite number of queries by deriving non-asymptotic and asymptotic bounds. Our bounds are tight in the first-order asymptotic sense when the number of queries satisfies a certain condition and our bounds are tight in the stronger second-order asymptotic sense when the target moves with a constant velocity. To prove our results, we relate the current problem to channel coding, borrow ideas from finite blocklength information theory and construct bounds on the number of possible quantized target trajectories.

Asfotase alfa improved skeletal mineralization and fracture healing in a child with MCAHS.

Tissue non-specific alkaline phosphatase (TNSALP) is an enzyme that is tethered to the cell membrane by glycosylphosphatidylinositol (GPI) and converts inorganic pyrophosphate to inorganic phosphate. Inorganic phosphate combines with calcium to form hydroxyapatite, the main mineral in the skeleton. When TNSALP is defective, conversion of inorganic pyrophosphate to inorganic phosphate is impaired and the skeleton is at risk of under-mineralization. Phosphatidylinositol glycan anchor biosynthesis class N (PIGN) is one of more than 20 genes in the GPI-biosynthesis family. Pathogenic variants in PIGN have been identified in multiple congenital anomalies-hypotonia-seizures syndrome (OMIM 614080), although a metabolic bone disease or skeletal fragility phenotype has not been reported. We describe a female child with multiple congenital anomalies-hypotonia-seizures syndrome due to a compound heterozygous pathogenic variant in PIGN who sustained a low-trauma distal femur fracture at age 7.4years. We hypothesized that the GPI synthesis defect may result in metabolic bone disease from inadequate anchoring of TNSALP in bone and initiated asfotase alfa, a human bone-targeted recombinant TNSALP-Fc-deca-aspartate peptide, as it could bypass the PIGN genetic defect that possibly caused her skeletal fragility. Asfotase alfa was begun at 8.5years. Baseline X-rays revealed mild rachitic findings of wrists and knees, which resolved by 5months of treatment. Bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry (DXA) showed mild improvement in spine, hip and total body less head after 16months of treatment, while radius declined. She sustained additional low trauma fractures at right tibia and left humeral neck at 11 and 15months into treatment, which healed quickly. Calcium, phosphorus, and parathyroid hormone levels have remained within the normal range over the 18months of treatment. For adverse effect, she experienced a rash and discomfort in the first week of treatment which resolved with ibuprofen and diphenhydramine. She also developed subcutaneous fat atrophy. Overall, in this child with a compound pathogenic variant in PIGN, off-label use of asfotase alfa has been generally well tolerated with minimal side effects and resolution of rickets, but she continues to remain skeletally fragile.

The structure of quasi-complete intersection ideals

We prove that every quasi-complete intersection (q.c.i.) ideal is obtained from a pair of nested complete intersection ideals by way of a flat base change. As a by-product we establish a rigidity statement for the minimal two-step Tate complex associated to an ideal I in a local ring R. Furthermore, we define a minimal two-step complete Tate complex T for each ideal I in a local ring R; and prove a rigidity result for it. The complex T is exact if and only if I is a q.c.i. ideal; and in this case, T is the minimal complete resolution of R/I by free R-modules.

Amorphous silicate technology produces good results in equine distal limb wound healing

The objective of this study was to report clinical outcomes of horses with naturally occurring full-thickness skin lacerations treated with an amorphous silicate dressing. We hypothesized that wounds treated with an amorphous silicate dressing would have minimal complications and lesion resolution without formation of exuberant granulation tissue. 11 client-owned horses. Clinical records of 11 horses with distal limb wounds treated with an amorphous silicate dressing were collected from participating veterinarians across the US. Wound healing progression was monitored by the veterinarian and owners. None of the wounds required granulation bed debridement following treatment with topical amorphous silicate dressing. There were no complications associated with the treatment. The size of wounds varied from 5 to 20 cm in length with a median of 10 cm and from 2 to 15 cm in width with a median of 5 cm. Time to resolution varied greatly from 14 to 126 days with a median of 49 days. There was a moderate positive correlation between healing time (days) and area of the wound. All referring veterinarians and owners were satisfied with the healing of the wounds treated with the amorphous silicate dressing. Treatment of equine distal limb wounds with an amorphous silicate dressing may reduce development of exuberant granulation tissue and the need for surgical debridement.

On the Possibility of Cross-Flow Vortex Cancellation by Plasma Actuators

Cancellation of the cross-flow vortices in a swept-wing boundary layer is attempted by plasma actuator array in numerical simulation. The response of the boundary layer to the stationary excitation by a single actuator section is measured experimentally and compared to the response obtained from the solution to the parabolized stability equations. A linear approach is shown to be held within the peak-to-peak magnitude of the stationary cross-flow vortices below 10% of the local potential flow velocity. Within the linear model, an optimal control strategy and a faster suboptimal one are developed to calculate voltage amplitude distribution across the electrodes, taking into account the forcing constraints. Simulation of the cancellation process is performed, showing up to a 20 dB reduction in the initial spanwise velocity modulation in the boundary layer. The minimal actuator resolution required for the successive implementation of the control is shown to be in the order of a quarter of the most amplified wavelength, or 3–4 displacement thickness of the boundary layer. Linear estimates predict up to a 150 mm (22% of flow acceleration region length) transition delay for an actuator momentum coefficient of 0.005%.

Ratiometric nanothermometer CaSc2O4: Nd3+ operating in biological window for deep-tissue photothermal therapy

Accurate and real-time temperature detection is an urgent requirement in photothermal therapy (PTT). In this work, the CaSc2O4: Nd3+ nanorod with an average length of 150 nm has been determined to be an outstanding optical thermometer based on the fluorescence intensity ratio (FIR) of thermally coupled Stark sublevels of Nd3+: 4F3/2 → 4I11/2 transition, of which the excitation and emission wavelength are located in the first and second biological window respectively, resulting in an 8 mm penetration depth in the biological tissues. The maximal absolute sensitivity and relative sensitivity as well as the minimal temperature resolution of the present sample is 0.0008 K-1, 0.0018 K-1 and 0.19 K respectively, which is superior to the vast majority of the same type thermometers. Besides that, the nanorods show a 7 K temperature increment after 180 s’ 808 nm-laser radiation, revealing its photothermal conversion capacity thanks to the considerable nonradiative relaxation processes among the metastable energy levels of Nd3+. These results indicate that Nd3+ single-doped CaSc2O4 nanorods can be utilized as the optical thermometer in the deep-tissue PTT process for real-time thermometry along with the function of light-to-heat conversion.

Large Interferometer For Exoplanets (LIFE)

Context.Terrestrial exoplanets in the habitable zone are likely a common occurrence. The long-term goal is to characterize the atmospheres of dozens of such objects. The Large Interferometer For Exoplanets (LIFE) initiative aims to develop a space-based mid-infrared (MIR) nulling interferometer to measure the thermal emission spectra of such exoplanets.Aims.We investigate how well LIFE could characterize a cloudy Venus-twin exoplanet. This allows us to: (1) test our atmospheric retrieval routine on a realistic non-Earth-like MIR emission spectrum of a known planet, (2) investigate how clouds impact retrievals, and (3) further refine the LIFE requirements derived in previous Earth-centered studies.Methods.We ran Bayesian atmospheric retrievals for simulated LIFE observations of a Venus-twin exoplanet orbiting a Sun-like star located 10 pc from the observer. The LIFESIMnoise model accounted for all major astrophysical noise sources. We ran retrievals using different models (cloudy and cloud-free) and analyzed the performance as a function of the quality of the LIFE observation. This allowed us to determine how well the atmosphere and clouds are characterizable depending on the quality of the spectrum.Results.At the current minimal resolution (R= 50) and signal-to-noise (S/N= 10 at 11.2 μ m) requirements for LIFE, all tested models suggest a CO2-rich atmosphere (≥30% in mass fraction). Further, we successfully constrain the atmospheric pressure-temperature (P–T) structure above the cloud deck (P–Tuncertainty ≤ ± 15 K). However, we struggle to infer the main cloud properties. Further, the retrieved planetary radius (Rpl), equilibrium temperature (Teq), and Bond albedo (AB) depend on the model. Generally, a cloud-free model performs best at the current minimal quality and accurately estimatesRpl,Teq, andAB. If we consider higher quality spectra (especiallyS/N= 20), we can infer the presence of clouds and pose first constraints on their structure.Conclusions.Our study shows that the minimal R and S/N requirements for LIFE suffice to characterize the structure and composition of a Venus-like atmosphere above the cloud deck if an adequate model is chosen. Crucially, the cloud-free model is preferred by the retrieval for low spectral qualities. We thus find no direct evidence for clouds at the minimalRandS/Nrequirements and cannot infer the thickness of the atmosphere. Clouds are only constrainable in MIR retrievals of spectra withS/N≥ 20. The model dependence of our retrieval results emphasizes the importance of developing a community-wide best-practice for atmospheric retrieval studies.