Alignment Efficiency Research Articles

B-fields and Dust in Interstellar Filaments Using Dust Polarization (BALLAD-POL). I. The Massive Filament G11.11–0.12 Observed by SOFIA/HAWC+

We report the first measurement of polarized thermal dust emission toward the entire infrared dark cloud G11.11−0.12 taken by the polarimeter SOFIA/HAWC+ at 214 μm. The obtained magnetic fields (B-fields) from the polarized emission of the early-stage and massive filament tend to be perpendicular to its spine. We produce a map of B-field strengths for the center region of the filament. The strengths vary in the range of 100–600 μG and are strongest along the filament's spine. The central region is sub-Alfvénic and mostly subcritical, meaning that B-fields dominate over turbulence and are strong enough to resist gravitational collapse. The alignment and properties of dust grains in the filament are studied using radiative torque (RAT) theory. We find the decrease of polarization degree P with emission intensity I, i.e., depolarization effect, of the form P ∝ I −α with α ∼ 0.8–0.9, implying a significant loss of grain alignment in the filament's spine. The depolarization can be explained by the decrease in RAT alignment efficiency toward the denser regions with weaker radiation field, which cannot be explained by B-field tangling. We study the effect of the enhanced magnetic relaxation by embedded iron inclusions on RAT alignment and find that the high polarization fraction P ∼ 20%–30% in the outer layer of the filament is potential evidence for the magnetically enhanced RAT alignment mechanism. This is the first time this effect is evaluated in a filament. Based on the polarization fraction and RAT alignment theory, we also find evidence for grain growth in the filament.

Physical conditions for dust grain alignment in Class 0 protostellar cores

Context. The polarized dust emission observed in Class 0 protostellar cores at high angular resolution with ALMA has raised several concerns about the grain alignment conditions in these regions. Aims. We aim to study the role of the radiation field in grain alignment mechanisms that occur in the interior (≤1000 au) of Class 0 protostars. Methods. We produced synthetic observations of the polarized dust emission from a magnetohydrodynamic model of protostellar formation using the POLARIS dust radiative transfer tool, which includes dust alignment with radiative torque alignment (RAT). We tested how the polarized dust emission from the model core depends on the irradiation conditions in the protostellar envelope by varying the radiation due to accretion luminosity propagating from the central protostellar embryo throughout the envelope. The level of grain alignment efficiency obtained in the radiative transfer models was then compared to (sub)millimeter ALMA dust polarization observations of Class 0 protostars. Results. Our radiative transfer calculations have a central irradiation that reproduces the protostellar luminosities typically observed toward low- to intermediate-mass protostars, as well as super-paramagnetic grains and grains ≥10 µm, which are required to bring the dust grain alignment efficiencies of the synthetic observations up to the observed levels. We discuss the characteristics timescales of the grain alignment physics together with the radiative torque disruption (RATD) of grains and the typical time variability of accretion occurring in Class 0 protostellar cores. In our model, during an accretion burst or a steady-state phase of high luminosity from the protostellar embryo, RATD could have enough time to disrupt the largest grains in irradiated regions. Finally, in high-luminosity conditions (with L★ ≥ 20 L⊙ in our model), we find that the alignment of grains with respect to the anisotropic component of the radiation field (k-RAT) could drive inefficient alignment for grains ≳10 µm. However, given the high grain alignment efficiency observed in protostellar envelopes, large grains are most likely aligned with the magnetic field and thus potentially subject to rotational disruption, depending on their tensile strength. Conclusions. Our radiative transfer calculations show that irradiation plays an important role in the mechanisms that dictate the size range of aligned grains in Class 0 protostars. Regions of the envelope that are preferentially irradiated harbor strong polarized dust emission but can be affected by the rotational disruption of dust grains, thus controlling the population of the largest aligned grains. Episodes of high luminosity could affect grain alignment and trigger grain disruption mechanisms.

Evaluation of pain, alignment efficiency, and post alignment anterior torque between I –Archwires and superelastic NiTi wires: A comparative study

: to compare the aligning efficiency, pain experienced by the patient during alignment and the post alignment third order values of anterior teeth in I arch (study) group and conventional NiTi (control) wire group.: A prospective clinical study.: A total of 40 dental arches (maxilla/mandible) were divided into 2 study groups with 20 dental arches (maxilla/mandible) in each group based on the selection criteria. Group I. Twenty dental arches (maxillary/mandibular) having 0.018” preadjusted appliance (MBT) brackets (ORMCO), aligned with I –arch 0.016”x0.014” copper NiTi wires. Group II. Twenty dental arches (maxillary/mandibular) having 0.018” preadjusted appliance (MBT) brackets by ORMCO aligned with round super elastic NiTi archwires.: I -arch copper NiTi (study group) was more efficient in alignment compared to the superelastic NiTi (control group) in the lower arch and the values are statistically significant. There was torque expression in the I-arch group as compared to the superelastic NiTi group. The subjects in the I-arch (study group) experienced lesser pain compared to the superelastic NiTi (control group) and the pain values are statistically significant.

A prospective randomized clinical study comparing the alignment efficiency of four different ligation methods

To conduct a prospective randomized study comparing the efficiency of four different ligation systems (ELL,SSL,LL,PSL) over the duration of mandibular crowding alleviation.The study was conducted in Department of Orthodontics and Dentofacial Orthopaedics, Noorul Islam College of Dental Sciences, Neyyattinkara, Trivandrum. The present study evaluated the variations in alignment efficiency of four different ligation systems over the duration of mandibular crowding alleviation in patients during mandibular crowding alleviation. Eighty patients fulfilling the inclusion criteria were selected and equally divided into four groups- Elastomeric ligation (ELL), Stainless steel Ligation (SSL)- active and passive , Leone slide Ligatures (LL).: The mean treatment time for alignment for passive self ligating group (102 days) followed by leone group (128 days), stainless steel (176 days) and elastomeric (224 days) group. Thus the study showed no significant difference in the clinical performance between coventional, self ligating, while PSL performed significantly superior to other groups. From the above equation, during initial phase of orthodontic treatment.self-ligating brackets were more efficient than conventional brackets in anterior alignment, passive space closure, and mandibular incisal inclination.

Far-infrared polarization of the supernova remnant Cassiopeia A with SOFIA HAWC +

ABSTRACT We present polarization observations of the young supernova remnant (SNR) Cas A using the High-resolution Airborne Wideband Camera-Plus (HAWC +) instrument onboard the Stratospheric Observatory for Infrared Astronomy (SOFIA). The polarization map at 154 $\mu$m reveals dust grains with strong polarization fractions (5–30 per cent), supporting previous measurements made over a smaller region of the remnant at 850 $\mu$m. The 154-$\mu$m emission and the polarization signal is coincident with a region of cold dust observed in the southeastern shell and in the unshocked central ejecta. The highly polarized far-IR emission implies the grains are large (>0.14 $\mu$m) and silicate-dominated. The polarization level varies across the SNR, with an inverse correlation between the polarization degree and the intensity and smaller polarization angle dispersion for brighter SNR emission. Stronger polarization is detected between the bright structures. This may result from a higher collision rate between the gas and dust producing a lower grain alignment efficiency where the gas density is higher. We use the dust emission to provide an estimate of the magnetic field strength in Cas A using the Davis–Chandrasekhar–Fermi method. The high polarization level is direct evidence that grains are highly elongated and strongly aligned with the magnetic field of the SNR. The dust mass from the polarized region is 0.14 ± 0.04 M⊙, a lower limit of the amount of dust present within the ejecta of Cas A. This result strengthens the hypothesis that core-collapse SNe are an important contributor to the dust mass in high redshift galaxies.

Numerical and experimental investigation of high-resolution manipulation of microparticles using a developed two-stage acoustofluidic platform

Acoustophoresis as an emerging label-free, biocompatible, and contactless technique in particle separation has attracted recent interest in the separation of cells and particles from heterogeneous samples. Improving separation resolution in many biological applications in which particles of close sizes must be separated is of great importance. To study the separation of microparticles with similar sizes, a two-stage acoustofluidic platform is developed in this study. The device uses acoustic and hydrodynamic focusing mechanisms to boost alignment efficiency in its first stage. The device's second module separates microparticles using standing acoustic waves. In both numerical and experimental studies, multiple parameters such as geometrical features, pressure distribution, and sheath-flow variation were investigated to optimize separation performance. The experimental results show that particles of sizes 8–10 µm can be separated with a purity of more than 80% and a throughput of 10 µl/min. As a potential application, the separation resolution demonstrated in the study can be applied to the separation of white blood cells, e.g., neutrophils from leukocytes.

Polymerization Strategies to Construct a 3D Polymer Passivation Network toward High Performance Perovskite Solar Cells.

The spontaneously formed uncoordinated Pb2+ defects usually make the perovskite films demonstrate strong n-type with relatively lower carrier diffusion length and serious non-radiative recombination energy loss. In this work, we adopt different polymerization strategies to construct three-dimensional passivation frameworks in the perovskite layer. Thanks to the strong C≡N⋅⋅⋅Pb coordination bonding and the penetrating passivation structure, the defect state density is obviously reduced, accompanied by a significant increase in the carrier diffusion length. Additionally, the reduction of iodine vacancies also changed the Fermi level of the perovskite layer from strong n-type to weak n-type, which substantially promotes the energy level alignment and carrier injection efficiency. As a result, the optimized device achieved an efficiency exceeded 24 % (the certified efficiency is 24.16 %) with a high open-circuit voltage of 1.194 V, and the corresponding module achieved an efficiency of 21.55 %.

Polymerization Strategies to Construct a 3D Polymer Passivation Network toward High Performance Perovskite Solar Cells

AbstractThe spontaneously formed uncoordinated Pb2+ defects usually make the perovskite films demonstrate strong n‐type with relatively lower carrier diffusion length and serious non‐radiative recombination energy loss. In this work, we adopt different polymerization strategies to construct three‐dimensional passivation frameworks in the perovskite layer. Thanks to the strong C≡N⋅⋅⋅Pb coordination bonding and the penetrating passivation structure, the defect state density is obviously reduced, accompanied by a significant increase in the carrier diffusion length. Additionally, the reduction of iodine vacancies also changed the Fermi level of the perovskite layer from strong n‐type to weak n‐type, which substantially promotes the energy level alignment and carrier injection efficiency. As a result, the optimized device achieved an efficiency exceeded 24 % (the certified efficiency is 24.16 %) with a high open‐circuit voltage of 1.194 V, and the corresponding module achieved an efficiency of 21.55 %.

Chromosome size affects alignment efficiency in mammalian mitosis.

The kinetochore connects chromosomes to spindle microtubules during cell division. Accurate chromosome segregation requires sister kinetochores to biorient, attaching to opposite spindle poles. To achieve biorientation, the kinetochore destabilizes incorrect attachments and stabilizes correct ones. How it discriminates correct from incorrect attachments is not clear. Here, we test the model that tension serves as the stabilizing cue at correct attachments and how that model affects chromosomes of different sizes. Live imaging of mitotic PtK2 cells reveals long chromosomes align at the metaphase plate more slowly than short chromosomes. Using laser ablation to shorten long chromosome arms—reducing polar ejection forces on them—we show that chromosomes align faster after ablation, indicating chromosome size affects alignment efficiency. Finally, artificially enriching for incorrect attachments using STLC washouts and imaging error correction live, we show that long chromosomes exhibit a delay in correcting errors, rather than simply in attachment formation. We propose a model where increased polar ejection forces on long chromosomes stabilize not only correct but also incorrect attachments, delaying their biorientation and alignment. As such, long chromosomes may experience more challenges correcting errors and, as a result, higher missegregation rates.

The Bardeen–Petterson effect, disc breaking, and the spin orientations of supermassive black hole binaries

ABSTRACT Supermassive black hole binaries are driven to merger by dynamical friction, loss-cone scattering of individual stars, disc migration, and gravitational wave emission. Two main formation scenarios are expected. Binaries that form in gas-poor galactic environments do not experience disc migration and likely enter the gravitational wave-dominated phase with roughly isotropic spin orientations. Comparatively, binaries that evolve in gas-rich galactic environments might experience prominent phases of disc accretion, where the Bardeen–Petterson effect acts to align the spins of the black holes with the orbital angular momentum of the disc. However, if the accretion disc breaks, alignment is expected to be strongly suppressed – a phenomenon that was recently shown to occur in a large portion of the parameter space. In this paper, we develop a semi-analytical model of joint gas-driven migration and spin alignment of supermassive black hole binaries taking into account the impact of disc breaking for the first time. Our model predicts the occurrence of distinct subpopulations of binaries depending on the efficiency of spin alignment. This implies that future gravitational wave observations of merging black holes could potentially be used to (i) discriminate between gas-rich and gas-poor hosts and (ii) constrain the dynamics of warped accretion discs.

Alignment efficiency and three-dimensional assessment of root resorption after alignment with conventional and copper-nickel-titanium archwires: A randomized controlled trial.

To compare alignment efficiency and root resorption between nickel-titanium (NiTi) and copper-nickel-titanium (CuNiTi) archwires after complete alignment in mandibular anterior region. In this two-arm parallel single-blind randomized controlled trial, forty-four patients with Class I malocclusion with mandibular anterior crowding were recruited form orthodontic clinic of All India Institute of Medical Sciences (Jodhpur, India). Patients were randomly allocated into NiTi and CuNiTi groups, with a 1:1 allocation. Alignment was performed using 0.014-in, 0.016-in, 0.018-in, 0.019x0.025-in archwire sequence in the respective groups, which terminated in 0.019 x 0.025-in stainless-steel working archwire. The primary outcome was alignment efficiency, measured on study models from baseline (T0) to the first, second, third, fourth and fifth-month (T5). Secondary outcome was root resorption, measured from CBCT scans taken at T0 and T5. Mixed-factorial ANOVA was used to compare Little's Irregularity Index (LII). For assessing the proportion of patients with complete alignment at the end of each month, Kaplan-Meier survival curve was built and time to treatment completion was compared between groups using log rank test. Paired t-test was used to assess external apical root resorption (EARR) within groups, whereas independent t-test was used to evaluate LII and EARR between the groups. Twenty-two patients were recruited in each group. One patient was lost to follow-up in the CuNiTi group. No statistically significant differences were observed in alignment efficiency between the groups (p>0.05). Intergroup comparison revealed that the changes in root measurement in three-dimensions were not statistically significant (p>0.05), except for mandibular right central incisor, which showed increased resorption at root apex in NiTi group (p<0.01). The two alignment archwires showed similar rate of alignment at all time points. Root resorption measurement did not differ between the NiTi and CuNiTi groups, except for the mandibular right central incisor, which showed more resorption in NiTi group.

Evaluating the efficiency of rail gauge maintenance in Siberia

The state of gauge geometry is the basis for safe and uninterrupted train operations under the mixed traffic conditions, as well as in the sections where trains with increased weight and length, including wagons with an increased axle load, are handled. When passing such trains, the state of gauge geometry deteriorates. This leads to increased labour costs for track maintenance, which is also caused by climatic features. Under such conditions, it is important to carry out effective gauge maintenance works. To analyse an impact of maintenance on gauge geometry, it is offered to determine the effect of uneven settlement of the under sleeper base in spring on the dynamics of each type of deviation. To evaluate the efficiency of preventive track alignment in the plan and profile, an analysis of graphical charts for the state of gauge geometry depending on track maintenance by gangs of track fitters and preventive track alignment by machine systems was carried out. It is also revealed that the efficiency of preventive alignment is significantly reduced under harsh climatic conditions, especially for the tonnage handled exceeding 600 million tonnes gross, and should therefore be carried out more frequently.

Alignment efficiency of heat activated and superelastic nickel-titanium archwires in orthodontic patients over three months: A Single-center, randomized clinical trial.

The aim of this 2-arm parallel study was to evaluate the alignment efficiency of heat-activated nickel-titanium (NiTi-TE) and superelastic nickel titanium (NiTi-PSE) archwires over the first 3 months of orthodontic treatment and compare these groups. Randomized, double-blind, controlled, single-center trial in 52 patients with fixed orthodontic appliances from an orthodontic graduate program in the permanent dentition and moderate crowding in the lower arch. Patients were randomly allocated to one of two interventions: NiTi-TE and NiTi-PSE archwires, 0.014-inch (3M Unitek™, CA, USA) with a follow-up period of 3 months. The primary outcome was the alignment efficiency determined by the reduction in Little's irregularity index (mm), measured in three points, T0: before the start of orthodontic treatment, T1: 1 month later, T2: 2 months later, T3: 3 months later. Data were analyzed using independent sample t tests and repeated measures ANOVA. 52 patients (NiTi-TE n = 26; NiTi-PSE n = 26) were randomized and analyzed (average age: 21.73; standard deviation (SD): 6.07; average lower anterior irregularity: 5.20; SD: 0.76) for intention-to-treat (ITT) analysis. No statistically significant differences between the groups were found (mean of the differences: T1: 0.20; 95% CI: -0.558; 0.958; T2: 0.49: 95% CI: -0.339; 1.319; T3: 0.33; 95% CI: -0.308; 0.968). The resolution of crowding with each of the wires was significant (P < 0.0001) at all times. Twelve participants (2 treated with NiTi-TE and 10 treated with NiTi-PSE) lost follow-up due to face-to-face dental-procedures restrictions during the COVID-19 pandemic, the missing data was imputed. NiTi-TE and NiTi-PSE wires of 0.014-inch were similar in their clinical efficiency for the resolution of crowding during the first 3 months of orthodontic treatment. Clinical Trials NCT03256279.

Automatic synchrotron tomographic alignment schemes based on genetic algorithms and human-in-the-loop software.

Tomography imaging methods at synchrotron light sources keep evolving, pushing multi-modal characterization capabilities at high spatial and temporal resolutions. To achieve this goal, small probe size and multi-dimensional scanning schemes are utilized more often in the beamlines, leading to rising complexities and challenges in the experimental setup process. To avoid spending a significant amount of human effort and beam time on aligning the X-ray probe, sample and detector for data acquisition, most attention has been drawn to realigning the systems at the data processing stages. However, post-processing cannot correct everything, and is not time efficient. Here we present automatic alignment schemes of the rotational axis and sample pre- and during the data acquisition process using a software approach which combines the advantages of genetic algorithms and human intelligence. Our approach shows excellent sub-pixel alignment efficiency for both tasks in a short time, and therefore holds great potential for application in the data acquisition systems of future scanning tomography experiments.

A novel next-generation sequencing capture-based strategy to report somatic hypermutation status using genomic regions downstream to immunoglobulin rearrangements.

The somatic hypermutation (SHM) status of the clonotypic, rearranged immunoglobulin heavy variable (IGHV) gene is an established prognostic and predictive marker in chronic lymphocytic leukemia (CLL). Analysis of SHM is generally performed by polymerase chain reaction (PCR)-amplification of clonal IGHV-IGHD-IGHJ gene rearrangements followed by sequencing to identify IGHV gene sequences and germline identity. Targeted-hybridization next-generation sequencing (NGS) can simultaneously assess clonality and other genetic aberrations. However, it has limitations for SHM analysis due to sequence similarity between different IGHV genes and mutations introduced by SHM, which can affect alignment efficiency and accuracy. We developed a novel SHM assessment strategy using a targeted-hybridization NGS approach (EuroClonality- NDC assay) and applied it to 331 samples of lymphoproliferative disorder (LPD). Our strategy focuses on analyzing the sequence downstream to the clonotypic, rearranged IGHJ gene up to the IGHM enhancer (IGHJ-E) which provides more accurate alignment. Overall, 84/95 (88.4%) CLL cases with conventional SHM data showed concordant SHM status, increasing to 91.6% when excluding borderline cases. Additionally, IGHJ-E mutation analysis in a wide range of pre- and post-germinal center LPD showed significant correlation with differentiation and lineage status, suggesting that IGHJ-E analysis is a promising surrogate marker enabling SHM to be reported using NGS-capture strategies and whole genome sequencing.

Symmetric nonconfocal Fabry–Perot cavity with a stable long optical path length and improved tolerance for angular alignment

Engineering of optical alignment tolerance between a laser source and a Fabry–Perot (FP) cavity is of great importance in optimizing a laser analysis system and saving costs in the additional alignment task. We propose a modification of the conventional confocal FP (CFP) cavity–a symmetric nonconfocal FP (SNFP) cavity with two identical spherical mirrors separated by a distance equal to half of the common radius of curvature. Numerical analysis of the two cavities reveals that the SNFP cavity has better off-axis stability and much better angular misalignment tolerance than the CFP cavity, even with a longer optical path length (OPL). The SNFP cavity provides a six-transit path length for a basic cavity mode that supports a 1.5-fold long OPL within the same volume as the CFP cavity, which is favorable for applications requiring limits on the footprint and weight of the cavity. In addition, a ray-tracing simulation with a disk-type source having an angular Gaussian distribution (α = β = 5 deg) reveals that the emission beam profile from the SNFP cavity is narrower than that from the CFP cavity. These results are expected to help reduce cavity loss and to improve alignment efficiency between the laser source and the FP cavity.

Compact QEPAS CO2 sensor system using a quartz tuning fork-embedded and in-plane configuration

A quartz-enhanced photoacoustic spectroscopy (QEPAS) system was developed based on a novel quartz tuning fork-embedded, and in-plane QEPAS technique, while increasing the efficiency of assembly alignment with the aid of 3D printing technology. In this paper, it was verified that the simplified numerical model enabled rapid optimization of the dimensions of the acoustic micro-resonator (AmR), and this was validated by experimental results. The optimized results are as follows: outer diameter = 3.2 mm, inner diameter = 0.5 mm, length = 6.77 mm. The acoustic transducer used a commercial quartz tuning fork with a resonance frequency of 30.69 kHz. After optimizing the laser wavelength modulation amplitude and the dimensions of the AmR, a minimum CO2 detection limit of 1.06 ppm was obtained, corresponding to a normalized noise equivalent absorption of 5.5 × 10−9 cm−1 WHz−1/2.

Point cloud registration method based on Particle Swarm Optimization algorithm and improved ICP

In order to achieve accurate wheel gripping by truss manipulators, accurate point cloud alignment of train wheels is required. In this paper, the wheels are detected by binocular laser displacement sensors. And accurate point cloud alignment is achieved by using the point cloud denoising and streamlining algorithm, particle swarm-based algorithm, and improved ICP algorithm for 3D point cloud data. The experimental results show that reducing noise and data volume can improve the stitching effect and alignment efficiency of 3D point cloud models. The algorithm of this paper is experimentally verified to be 43% better in error accuracy and 93% faster in time-consuming than the traditional ICP algorithm, which verifies the effectiveness of its method.

Artificial Intelligence and Public Human Resource Management: Questions for Research and Practice

Advances in big data and artificial intelligence (AI), including machine learning (ML) and other cognitive computing technologies (CCT), have facilitated the development of human resource management (HRM) applications promising greater efficiency, economy, and effectiveness for public administration (Maciejewski, 2017) and better alignment with the modern, constantly evolving employment landscape. It is not surprising then that these advanced technologies are featured in proposals to elevate the government’s human capital. This article discusses current and emerging AI applications that stand to impact most (if not all) HRM functions and their prospects for elevating public human capital. In particular, this article (a) reviews the current state of the field with regards to AI and HRM, (b) discusses AI’s current and potential impact upon the core functional areas of HRM, (c) identifies the main challenges AI poses to such concerns as public values, equity, and traditional merit system principles, and (d) concludes by identifying research needs for public HRM scholarship and practice that highlight the growing role and influence of AI applications in the workplace.

Diffractive interconnects: all-optical permutation operation using diffractive networks

Abstract Permutation matrices form an important computational building block frequently used in various fields including, e.g., communications, information security, and data processing. Optical implementation of permutation operators with relatively large number of input–output interconnections based on power-efficient, fast, and compact platforms is highly desirable. Here, we present diffractive optical networks engineered through deep learning to all-optically perform permutation operations that can scale to hundreds of thousands of interconnections between an input and an output field-of-view using passive transmissive layers that are individually structured at the wavelength scale. Our findings indicate that the capacity of the diffractive optical network in approximating a given permutation operation increases proportional to the number of diffractive layers and trainable transmission elements in the system. Such deeper diffractive network designs can pose practical challenges in terms of physical alignment and output diffraction efficiency of the system. We addressed these challenges by designing misalignment tolerant diffractive designs that can all-optically perform arbitrarily selected permutation operations, and experimentally demonstrated, for the first time, a diffractive permutation network that operates at THz part of the spectrum. Diffractive permutation networks might find various applications in, e.g., security, image encryption, and data processing, along with telecommunications; especially with the carrier frequencies in wireless communications approaching THz-bands, the presented diffractive permutation networks can potentially serve as channel routing and interconnection panels in wireless networks.