Large Initial Differences Research Articles

Robust Point Cloud Registration Network for Complex Conditions.

Point cloud registration is widely used in autonomous driving, SLAM, and 3D reconstruction, and it aims to align point clouds from different viewpoints or poses under the same coordinate system. However, point cloud registration is challenging in complex situations, such as a large initial pose difference, high noise, or incomplete overlap, which will cause point cloud registration failure or mismatching. To address the shortcomings of the existing registration algorithms, this paper designed a new coarse-to-fine registration two-stage point cloud registration network, CCRNet, which utilizes an end-to-end form to perform the registration task for point clouds. The multi-scale feature extraction module, coarse registration prediction module, and fine registration prediction module designed in this paper can robustly and accurately register two point clouds without iterations. CCRNet can link the feature information between two point clouds and solve the problems of high noise and incomplete overlap by using a soft correspondence matrix. In the standard dataset ModelNet40, in cases of large initial pose difference, high noise, and incomplete overlap, the accuracy of our method, compared with the second-best popular registration algorithm, was improved by 7.0%, 7.8%, and 22.7% on the MAE, respectively. Experiments showed that our CCRNet method has advantages in registration results in a variety of complex conditions.

The European landscape on allogeneic haematopoeietic cell transplantation in Chronic Lymphocytic Leukaemia between 2009 and 2019: a perspective from the Chronic Malignancies Working Party of the EBMT.

Allogeneic transplantation (allo-HCT) is a curative treatment in CLL whose efficacy including the most severe forms had led to the 2006 EBMT recommendations. The advent after 2014 of targeted therapies has revolutionized CLL management, allowing prolonged control to patients who have failed immunochemotherapy and/or have TP53 alterations. We analysed the pre COVID pandemic 2009-2019 EBMT registry. The yearly number of allo-HCT raised to 458 in 2011 yet dropped from 2013 onwards to an apparent plateau above 100. Within the 10 countries who were under the EMA for drug approval and performed 83.5% of those procedures, large initial differences were found but the annual number converged to 2-3 per 10 million inhabitants during the 3 most recent years suggesting that allo-HCT remains applied in selected patients. Long-term follow-up on targeted therapies shows that most patients relapse, some early, with risk factors and resistance mechanisms being described. The treatment of patients exposed to both BCL2 and BTK inhibitors and especially those with double refractory disease will become a challenge in which allo-HCT remains a solid option in competition with emerging therapies that have yet to demonstrate their long-term effectiveness.

Examining moderators of vocabulary acquisition from kindergarten through elementary school using local structural equation modeling

Parental socio-economic status (SES) is often found to be associated with children's language competence in the first decade of life. To examine the effect of SES on children's vocabulary development, as well as potential compensatory effects of schooling and learning-related activities, we examined the joint and unique effects of parental education, occupational status, and learning environment at home on children's receptive vocabulary competence and growth in early childhood. We used latent growth curve models to assess pre-school receptive vocabulary and growth across primary school. Analyses were based on data from the German National Educational Panel Study (NEPS), a large-scale longitudinal study assessing vocabulary competence and family background from Kindergarten to the 3rd grade of elementary school. To examine the moderating effects of parental education, occupational status, and learning environment at home, we used local structural equation modeling. Results revealed a moderate to strong positive association between parental education and children's receptive vocabulary competence, which fully explained the effect of occupational status on this language skill. With the exception of the activity of reading aloud, we found no effect of learning environment at home. Initially lower performing children showed steeper growth trajectories across school, but rank-orders were relatively stable across time. In summary, the results suggest large initial differences in receptive vocabulary between children from different educational backgrounds, which are reduced, but not fully overcome across elementary school.

Understanding node-link and matrix visualizations of networks: A large-scale online experiment

AbstractWe investigated human understanding of different network visualizations in a large-scale online experiment. Three types of network visualizations were examined: node-link and two different sorting variants of matrix representations on a representative social network of either 20 or 50 nodes. Understanding of the network was quantified using task time and accuracy metrics on questions that were derived from an established task taxonomy. The sample size in our experiment was more than an order of magnitude larger (N = 600) than in previous research, leading to high statistical power and thus more precise estimation of detailed effects. Specifically, high statistical power allowed us to consider modern interaction capabilities as part of the evaluated visualizations, and to evaluate overall learning rates as well as ambient (implicit) learning. Findings indicate that participant understanding was best for the node-link visualization, with higher accuracy and faster task times than the two matrix visualizations. Analysis of participant learning indicated a large initial difference in task time between the node-link and matrix visualizations, with matrix performance steadily approaching that of the node-link visualization over the course of the experiment. This research is reproducible as the web-based module and results have been made available at: https://osf.io/qct84/.

Fast Frequency Acquisition and Phase Locking of Nonplanar Ring Oscillators

Optical phase locking is a critical technique in space coherent optical communication and active coherent laser beam combining. In a typical optical phase locking loop based on nonplanar ring oscillators, the pull-in range is normally less than 1 MHz, limited by loop delay and frequency tuning bandwidth of the laser source. Phase locking cannot be achieved at large initial frequency differences. In this work, a fast laser frequency acquisition method is demonstrated. The frequency difference between the signal and local lasers was measured via frequency dividing and period counting, and the frequency control signal was generated by a frequency discrimination and control module, to reduce the frequency difference to the pull-in range of the loop. Under the coordinating function of the loop filter and the frequency discrimination and control module, phase locking under a large initial frequency difference was achieved. The frequency acquisition range reached 164 MHz, and the acquisition and locking time was measured to be 440 ms. Additionally, the acquisition time was shortened with the decrease in initial frequency difference.

Effect of Mixed Basic Military Training on the Physical Fitness of Male and Female Soldiers.

Mixed gender basic military training (BMT) is adopted to integrate the female South African soldier into the military. This study aimed to assess gender differences before, during (12 weeks), and after a 20-week mixed BMT course and determine if BMT significantly reduced these differences. A total of 186 soldiers (114 male: mean age = 21.0 ± 1.1 year; 72 female: mean age = 20.5 ± 1.2 year) completed the BMT course and all anthropometric, physical fitness, explosive power, and hand grip strength measurements. Repeated-measures analysis of variance was used to model BMT data with main effects for gender comparison between males and females, and time main effect for evaluation of differences between weeks 1, 12, and 20 of BMT, as well as an interaction effect for differences in changes over time for males and females. Alpha was set at α ≤0.05. Male soldiers were significantly taller (p < 0.001) and scored better in all measurements at the start of BMT, differences ranged from 1.6% to 50% between genders. Differences narrowed by up to 18.5% in aerobic, push-up, abdominal measurements, and to 4.6% in the South African National Defense Force fitness test. Differences in power output and hand grip strength remained unchanged. Large initial anthropometrical and physical fitness differences decreased but were still obvious at the end of BMT. BMT should bridge the physical gap between male and female soldiers to ensure they can all perform the same duties. The enforcing of equal minimum physical fitness requirements for acceptance into BMT; conditional acceptance into the military subject to the successful completion of a bridging course aimed at improving physical fitness in individuals who do not meet the minimum physical fitness requirements for acceptance; and developing a cyclic physical training program with different entry points, dependent on initial physical performance at the start of BMT, ensuring adequate progression and overload for all soldiers are possible avenues to explore to achieve this goal.

CLIL theory and empirical reality – Two sides of the same coin?

This article summarizes the essential theoretical and empirical findings of a large-scale doctoral dissertation study on content and language integrated learning (CLIL) streams at German secondary schools (Gymnasium) with up to three content subjects taught in English (Rumlich, 2016). A theoretical account rooted in teaching English as a foreign language (EFL), language acquisition and educational psychology provides the basis for the development of a comprehensive longitudinal model of general EFL proficiency, which incorporates cognitive, affective-motivational, and further individual variables. In a second step, the model is used to estimate the effects of CLIL on general EFL proficiency, EFL self-concept and interest over a span of two school years (Year 6 to Year 8). The statistical evaluation of the quasi-experimental data from 1,000 learners finds large initial differences prior to CLIL due to selection, preparation, and class composition effects brought about by the implementation of CLIL within streams. After two years, the analyses found no CLIL-related benefits for general EFL proficiency or interest in EFL classes and solely a minor increase in EFL self-concept that might be attributable to CLIL. The results make a strong claim for comprehensive longitudinal model-based evaluations and the inclusion of selection, preparation, and class composition effects when conducting research on CLIL programmes in similar settings. The findings also suggest that not all language competences and affective-motivational dispositions might benefit from CLIL (the way it is currently taught in Germany) to the same extent.

A microfluidic method and custom model for continuous, non-intrusive biofilm viscosity measurements under different nutrient conditions.

Straight, low-aspect ratio micro flow cells are used to support biofilm attachment and preferential accumulation at the short side-wall, which progressively reduces the effective channel width. The biofilm shifts downstream at measurable velocities under the imposed force from the constant laminar co-flowing nutrient stream. The dynamic behaviour of the biofilm viscosity is modeled semi-analytically, based on experimental measurements of biofilm dimensions and velocity as inputs. The technique advances the study of biofilm mechanical properties by strongly limiting biases related to non-Newtonian biofilm properties (e.g., shear dependent viscosity) with excellent time resolution. To demonstrate the proof of principle, young Pseudomonas sp. biofilms were analyzed under different nutrient concentrations and constant micro-flow conditions. The striking results show that large initial differences in biofilm viscosities grown under different nutrient concentrations become nearly identical in less than one day, followed by a continuous thickening process. The technique verifies that in 50 h from inoculation to early maturation stages, biofilm viscosity could grow by over 2 orders of magnitude. The approach opens the way for detailed studies of mechanical properties under a wide variety of physiochemical conditions, such as ionic strength, temperature, and shear stress.

Is There Negative Social Influence? Disentangling Effects of Dissimilarity and Disliking on Opinion Shifts

Empirical studies are inconclusive about the underlying mechanisms that shape the interrelated dynamics of opinions and interpersonal attraction. There is strong evidence that others whom are liked have a positive influence on opinions and similarities induce attraction (homophily). We know less about “negative” mechanisms concerning whether disliked others induce shifts away from consensus (negative influence), whether large differences (dissimilarity) generate distancing, and whether dissimilarities induce disliking (heterophobia). This study tests discriminating hypotheses about the presence of positive and negative mechanisms in controlled experiments involving dyadic interactions. Results confirm the presence of homophily, do not support the existence of negative social influence, and show a robust positive linear relationship between opinion distance and opinion shifts. This implies that contact might provide the largest push towards consensus in case of large initial differences.

Discrepancy and Disliking Do Not Induce Negative Opinion Shifts.

Both classical social psychological theories and recent formal models of opinion differentiation and bi-polarization assign a prominent role to negative social influence. Negative influence is defined as shifts away from the opinion of others and hypothesized to be induced by discrepancy with or disliking of the source of influence. There is strong empirical support for the presence of positive social influence (a shift towards the opinion of others), but evidence that large opinion differences or disliking could trigger negative shifts is mixed. We examine positive and negative influence with controlled exposure to opinions of other individuals in one experiment and with opinion exchange in another study. Results confirm that similarities induce attraction, but results do not support that discrepancy or disliking entails negative influence. Instead, our findings suggest a robust positive linear relationship between opinion distance and opinion shifts.

Robust adaptive attitude synchronisation of rigid body networks onSO(3)

In this study, the authors consider the robust adaptive attitude synchronisation problem for a network of rigid body agents using a modified version of the error function, which is recently introduced for constructing the attitude errors on SO(3). These attitude error vectors are particularly useful for networks with large initial attitude difference. They focus on devising an adaptive geometric approach to cope with situations where the inertia matrices are not available for measurement. The Frobenious norm is used as a measure for the difference between the actual values of moments of inertias and their estimated values, to construct the individual adaptive laws of agents. Compared to the previous methods for synchronisation on SO(3) such as those using quaternions, the authors' approach based on the introduced modified error function enables us to avoid any ambiguity for attitude representation. Finally, they study the robustness of the synchronisation task in the presence of external disturbances and unmodelled dynamics and propose a method to attenuate such effects. Simulation results illustrate the effectiveness of the proposed approach.

Two-level optimization approach for Mars orbital long-duration, large non-coplanar rendezvous phasing maneuvers

A relative dynamics equation-set based on orbital element differences with J2 effects is derived, based on which a two-level approach is proposed to optimize the Mars orbital rendezvous phasing with a large difference in the initial ascending node. The up-level problem uses the revolution deviation between the target spacecraft and the chaser as the design variable, and employs a linear search to find the optimum. The low-level problem uses the maneuver revolutions, locations, and impulses as the design variables, and is solved using a hybrid genetic algorithm combined with sequential quadratic programming. To improve the solution accuracy, an iteration method is developed to satisfy the terminal constraints of the absolute numerical integration trajectory. Test cases involving Mars sample return missions with large initial node differences are presented, which show that the relative dynamics, two-level optimization model, and hybrid optimization algorithm are efficient and robust. Compared with previously published results, the total velocity increment has been further reduced by utilizing this proposed approach. It is found that a five-impulse plan requires the least quantity of propellant, and a propellant-optimal minimum rendezvous duration exists for this long-duration, large non-coplanar rendezvous problem.

Study of the accumulation of grains in a two dimensional vibrated U-tube without interstitial fluid

We present an experimental and computational study using Molecular Dynamics simulations of the development of an accumulation of grains in one side of a two dimensional U-tube under vertical vibrations. Studying the evolution of the height difference between the columns of grains in the branches of the tube, we found that it reaches a saturation value after vibrating for some time. We obtain that this saturation value is the same if the simulation or experiment start with the arms leveled or with a large initial height difference. We explore computationally the effect of the width of the tube, the density of the grains and the coefficient of restitution between the grains and the wall on the value of the saturation. We obtain a value of the width of the tube for which the saturation value reaches a maximum, and show that the transport of grains between arms is favored for low grain densities and high grain-wall restitution coefficient.

Diagnosing Snowband Predictability Using a Multimodel Ensemble System

Abstract The forecast uncertainty of mesoscale snowband formation and evolution is compared using predictions from a 16-member multimodel ensemble at 12-km grid spacing for the 25 December 2002, 12 February 2006, and 14 February 2007 northeast U.S. snowstorms. Using these predictions, the case-to-case variability in the predictability of band formation and evolution is demonstrated. Feature-based uncertainty information is also presented as an example of what may be operationally feasible from postprocessing information from future short-range ensemble forecast systems. Additionally, the initial condition sensitivity of band location in each case is explored by contrasting the forecast evolutions of initial condition members with large differences in snowband positions. Considerable uncertainty in the occurrence, and especially timing and location, of band formation and subsequent evolution was found, even at forecast projections &amp;lt;24 h. The ensemble provided quantitative mesoscale band uncertainty information, and differentiated between high-predictability (14 February 2007) and low-predictability (12 February 2006) cases. Among the three cases, large (small) initial differences in the upper-level PV distribution and surface mean sea level pressure of the incipient cyclone were associated with large (small) differences in forecast snowband locations, suggesting that case-to-case differences in predictability may be related to the quality of the initial conditions. The complexity of the initial flow may also be a discriminator. Error growth was evident in each case, consistent with previous mesoscale predictability research, but predictability differences were not correlated to the degree of convection. Discussion of these results and future extensions of the work are presented.

In situ investigation of metal's microwave sintering

In this paper, we present the in-situ investigation on microstructure evolution of metal powders during microwave sintering by using synchrotron radiation X-ray computed tomography (SR-CT) technique. Through the experimental reconstructed images, sequential 2-D and 3-D microstructure evolution phenomena of the same grains set were clearly observed, such as the rearrangement and migration of particles, the formation and growth of sintering neck, and the removal of large initial differences in surface curvature. Moreover, anomalous sintering neck growth kinetics mechanisms (log( x/a) − log ( t)) during microwave sintering process were revealed and compared with the conventional sintering experiment, the reasons for these phenomena may be the “non-thermal effects”.

Prediction of ammonia emission from dairy cattle manure based on milk urea nitrogen: Relation of milk urea nitrogen to ammonia emissions

The main objectives of this study were to assess the relationship between ammonia emissions from dairy cattle manure and milk urea N (MUN; mg/dL) and to test whether the relationship was affected by stage of lactation and the dietary crude protein (CP) concentration. Twelve lactating multiparous Holstein cows were randomly selected and blocked into 3 groups of 4 cows intended to represent early [123±26 d in milk (DIM)], mid (175±3 DIM), and late (221±12 DIM) lactation stages. Cows within each stage of lactation were randomly assigned to a treatment sequence within a split-plot Latin square design balanced for carryover effects. Stage of lactation formed the main plots (squares) and dietary CP levels (15, 17, 19, and 21% of diet dry matter) formed the subplots. The experimental periods lasted 7 d, with d 1 to 6 used for adjustment to diets and d 7 used for total collection of feces and urine as well as milk sample collection. The feces and urine from each cow were mixed in the proportions in which they were excreted to make slurry that was used to measure ammonia emissions at 22.5°C over 24h using flux chambers. Samples of manure slurry were taken before and after ammonia emission measurements. The amount of slurry increased by 22% as dietary CP concentration increased from 15 to 21%, largely because of a greater urine volume (25.3 to 37.1kg/d). Initial urea N concentration increased linearly with dietary CP from 153.5 to 465.2mg/dL in manure slurries from cows fed 15 to 21% CP diets. Despite the large initial differences, the final concentration of urea N in manure slurries was less than 10.86mg/dL for all dietary treatments. The final total ammoniacal N concentration in manure slurries increased linearly from 228.2 to 508.7mg/dL as dietary CP content increased from 15 to 21%. Ammonia emissions from manure slurries ranged between 57 and 149g of N/d per cow and increased linearly with dietary CP content, but were unaffected by stage of lactation. Ammonia emission expressed as a proportion of N intake increased with percentage CP in the diet from about 12 to 20%, whereas ammonia emission as a proportion of urinary urea N excretion decreased from 67 to 47%. There was a strong relationship between ammonia emission and MUN [ammonia emission (g/d per cow)=25.0 (±6.72)+5.03 (±0.373) × MUN (mg/dL); R2=0.85], which was not different among lactation stages. Milk urea N concentration is one of several factors that allows prediction of ammonia emissions from dairy cattle manure.

Mass Sensing Based on Deterministic and Stochastic Responses of Elastically Coupled Nanocantilevers

Coupled nanomechanical systems and their entangled eigenstates offer unique opportunities for the detection of ultrasmall masses. In this paper we show theoretically and experimentally that the stochastic and deterministic responses of a pair of coupled nanocantilevers provide different and complementary information about the added mass of an analyte and its location. This method allows the sensitive detection of minute quantities of mass even in the presence of large initial differences in the active masses of the two cantilevers. Finally, we show the fundamental limits in mass detection of this sensing paradigm.

A longitudinal examination of the role of stereotype threat and racial climate on college outcomes for minorities at elite institutions

This paper employs hierarchical linear models to explore the long-term effects of stereotype threat on college outcomes for students in the National Longitudinal Survey of Freshmen. Performance burden was negatively related to both grades and social satisfaction with college. Social satisfaction with college was also significantly impacted by students’ perception of the campus racial climate. This paper examines the combined impact of performance burden, campus racial climate, cumulative GPA, and social life satisfaction early in college on 4 year graduation rates. Overall, while there are large initial differences in the likelihood of graduating on time for black and Hispanic students relative to whites, these differences are completely explained by assessments of campus racial climate, social life satisfaction, and grades. The findings suggest that interventions to reduce stereotype threat and improve the racial atmosphere on campus may go a long way towards reducing—and in some cases eliminating—disparities between racial/ethnic groups in college outcomes.

Müllerian mimicry: an examination of Fisher's theory of gradual evolutionary change

In 1927, Fisher suggested that Müllerian mimicry evolution could be gradual and driven by predator generalization. A competing possibility is the so-called two-step hypothesis, entailing that Müllerian mimicry evolves through major mutational leaps of a less-protected species towards a better-protected, which sets the stage for coevolutionary fine-tuning of mimicry. At present, this hypothesis seems to be more widely accepted than Fisher's suggestion. We conducted individual-based simulations of communities with predators and two prey types to assess the possibility of Fisher's process leading to a common prey appearance. We found that Fisher's process worked for initially relatively similar appearances. Moreover, by introducing a predator spectrum consisting of several predator types with different ranges of generalization, we found that gradual evolution towards mimicry occurred also for large initial differences in prey appearance. We suggest that Fisher's process together with a predator spectrum is a realistic alternative to the two-step hypothesis and, furthermore, it has fewer problems with purifying selection. We also examined the factors influencing gradual evolution towards mimicry and found that not only the relative benefits from mimicry but also the mutational schemes of the prey types matter.

Long‐term disadvantages of selective root placement: root proliferation and shoot biomass of two perennial grass species in a 2‐year experiment

Summary The long‐term benefits of root foraging in heterogeneous environments are unclear. The short duration of many previous studies may have overlooked the effects of patch depletion and root turnover, which may limit the long‐term rewards of root foraging for perennial plants. The benefits of root foraging were investigated for Holcus lanatus and Nardus stricta over two growing seasons. Shoot biomass of each species was measured in homogeneous nutrient‐rich and nutrient‐poor treatments and in a heterogeneous treatment consisting of a nutrient‐rich and a nutrient‐poor side, at a high and a low overall level of nutrient availability at the same patch contrast. Large initial differences in nitrate concentrations in the soil solution between the soil types disappeared so that, after several months, nitrate levels were low in all soil types. In heterogeneous treatments, Holcus was able to proliferate roots in the nutrient‐rich side compared with the nutrient‐poor side, but only at the high overall level of nutrient availability. Nardus did not selectively place roots in the nutrient‐rich side of the heterogeneous treatment at either nutrient level. Root longevity, as determined by minirhizotron observations, revealed that roots of Holcus tended to be shorter lived than those of Nardus, and to live longer in nutrient‐poor soils. Initially, Holcus produced more shoot biomass in the heterogeneous treatments, at both overall levels of nutrient availability, than expected from values in the homogeneous treatments, but this advantage disappeared by the end of the first growing season and, after 2 years, shoot biomass in the heterogeneous treatments was much less than expected. At the high overall level of nutrient availability, Holcus shoot biomass was not significantly greater than that produced in the homogeneous nutrient‐poor treatment. In contrast, shoot biomass of Nardus in the heterogeneous treatment was similar to the expected value, both after the first and second growing seasons. For Holcus, fast root proliferation and presumably a high nutrient uptake resulted in increased shoot biomass in the short term, but this was then curtailed by rapid patch depletion and high losses due to a limited root life span. We discuss the implications for the long‐term rewards of root proliferation in perennial species of heterogeneous environments.