bluuebunny/crossref_metadata_2025_split huggingface dataset:
Robust optimal control of the multi‐input systems with unknown disturbance based on adaptive integral reinforcement learning Q‐function
Authors: Lv Yongfeng , Zhao Jun , Li Rong , Ren Xuemei 
Published: January 2024

AbstractConsidering overshoot and chatter caused by the unknown interference, this article studies the adaptive robust optimal controls of continuous‐time (CT) multi‐input systems with an approximate dynamic programming (ADP) based Q‐function scheme. An adaptive integral reinforcement learning (IRL) scheme is proposed to study the optimal solutions of Q‐functions. First, multi‐input value functions are presented, and Nash equilibrium is analyzed. A complex Hamilton–Jacobi–Issacs (HJI) equation is constructed with the multi‐input system and the zero‐sum‐game‐based value function. It is a challenging task to solve the HJI equation for nonlinear system. Thus, A transformation of the HJI equation is constructed as a Q‐function. The neural network (NN) is applied to learn the solution of the transformed Q‐functions based on the adaptive IRL scheme. Moreover, an error information is added to the Q‐function for the issue of insufficient initial incentives to relax the persistent excitation (PE) condition. Simultaneously, an IRL signal of the critic networks is introduced to study the saddle‐point intractable solution, such that the system drift and NN derivatives in the HJI equation are relaxed. The convergence of weight parameters is proved, and the closed‐loop stability of the multi‐system with the proposed IRL Q‐function scheme is analyzed. Finally, a two‐engine driven F‐16 aircraft plant and a nonlinear system are presented to verify the effectiveness of the proposed adaptive IRL Q‐function scheme.
Into the ice: Exploration and data capturing in glacial moulins by a tethered robot
Authors: Polzin Max , Hughes Josie 
Published: January 2024

AbstractGlacial moulins (cylindrical meltwater drainage shafts) provide valuable insights into glacier dynamics, but are inaccessible and hazardous environments for humans to study. Exploring them using passive sensor probes has revealed their complex geometry, which has limited further exploration with passive sensor probes. To overcome these challenges, we propose a tethered robot capable of autonomously exploring and capturing data in glacial moulins. Our novel robot is equipped with a tether to support its motion. Combined with novel estimation and control algorithms, the tethered robot is able to safely and efficiently maneuver in confined, chimney‐like structures, such as moulins. Laboratory and field experiments confirm the feasibility of the proposed design, showing successful localization in environments with no access to positional measurements. Field trials on the Mer de Glace glacier demonstrate the robot's capabilities, descending into the largest moulin to depths of 25 m, capturing valuable scientific data. Onboard sensors are used to capture data to reconstruct the moulin's three‐dimensional geometry and two sampling mechanisms are presented and evaluated to extract samples from the icy surface of the moulin. Our results show promising potential for future exploration of moulins, demonstrating the effectiveness of our tethered robot for safely gathering data from these hazardous environments.
Comparing real and simulated performance for an off‐road autonomous ground vehicle in obstacle avoidance
Authors: Carruth Daniel W. , Goodin Christopher , Dabbiru Lalitha , Scherrer Nicklaus , Moore Marc N. , Hudson Christopher H. , Cagle Lucas D. , Jayakumar Paramsothy 
Published: January 2024

AbstractThis field report presents the results of a study of obstacle detection and avoidance (ODOA) by an autonomous ground vehicle (AGV) in off‐road driving conditions. This study included both real and simulated testing of the AGV and served as the third and final phase of a 3‐year research project studying the influence of environmental conditions over autonomous driving. We compare and contrast the results of the real and experimental field testing and report our findings on the influence of soft soil in ODOA performance by an AGV. We find that rutting in soft soil results in higher throttle effort but lower steering effort and speed. The results of these experiments will inform future studies of autonomous driving on off‐road environments.
Lipidomics Investigation Reveals the Reversibility of Hepatic Injury by Silica Nanoparticles in Rats After a 6‐Week Recovery Duration
Authors: Zhao Xinying , Zhu Yawen , Yao Qing , Zhao Bosen , Lin Guimiao , Zhang Min , Guo Caixia , Li Yanbo 
Published: January 2024

AbstractGiven the inevitable human exposure owing to its increasing production and utilization, the comprehensive safety evaluation of silica nanoparticles (SiNPs) has sparked concerns. Substantial evidence indicated liver damage by inhaled SiNPs. Notwithstanding, few reports focused on the persistence or reversibility of hepatic injuries, and the intricate molecular mechanisms involved remain limited. Here, rats are intratracheally instilled with SiNPs in two regimens (a 3‐month exposure and a subsequent 6‐week recovery after terminating SiNPs administration) to assess the hepatic effects. Nontargeted lipidomics revealed alterations in lipid metabolites as a contributor to the hepatic response and recovery effects of SiNPs. In line with the functional analysis of differential lipid metabolites, SiNPs activated oxidative stress, and induced lipid peroxidation and lipid deposition in the liver, as evidenced by the elevated hepatic levels of ROS, MDA, TC, and TG. Of note, these indicators showed great improvements after a 6‐week recovery, even returning to the control levels. According to the correlation, ROC curve, and SEM analysis, 11 lipids identified as potential regulatory molecules for ameliorating liver injury by SiNPs. Collectively, the work first revealed the reversibility of SiNP‐elicited hepatotoxicity from the perspective of lipidomics and offered valuable laboratory evidence and therapeutic strategy to facilitate nanosafety.
“The Most Important Thing Is to Make Them Aware”: A Case Study of Teacher Metalanguage Knowledge and Explicit L2 Pronunciation Instruction
Authors: Gordon Joshua , Arias Roger Segura 
Published: January 2024

AbstractAlthough explicit instruction is effective in helping second language (L2) learners develop intelligible pronunciation, it is necessary to understand why and how L2 teachers implement such explicit pronunciation instruction systematically in class. Because of its key role in enhancing learners’ pronunciation skills, understanding the rationale behind the implementation of explicit instruction by teachers in different contexts is necessary. A key aspect of analysis in the implementation of explicit pronunciation instruction is the teacher's metalanguage knowledge, which could showcase a key component of pronunciation teachers’ ability to present phonetic‐phonological content in an accessible manner to learners during explicit instruction. This case study analyzed an experienced English‐as‐a‐foreign‐language (EFL) teacher's metalanguage knowledge in L2 pronunciation instruction. Using qualitative data‐collection methods (e.g., semi‐structured interviews, classroom observations, and stimulated‐recall interviews), and Freeman's (2020) Knowledge Base of Language Teaching Framework, the results of this study showcase the way an experienced teacher's metalanguage knowledge influenced the implementation of explicit L2 pronunciation instruction, and how the teacher's metalanguage shaped the type of language available to learners in different activities in class. These results are also discussed in terms of their implications for training teachers in L2 pronunciation pedagogy.
Isolated traumatic orbital floor fracture: An analysis of the National Trauma Data Bank
Authors: De Ravin Emma , Xu Katherine , Fritz Christian , Parhar Harman S. , Rajasekaran Karthik 
Published: January 2024

AbstractObjectivesTo date, no study provides a comprehensive analysis of traumatic orbital floor fractures across the United States. We aimed to characterize patient demographics, injury‐related variables, and operative management in this population.MethodThe National Trauma Data Bank was queried for open or closed orbital floor fractures from 2008 to 2016. Clinical data were extracted.ResultsOverall, 148,592 orbital floor fractures were identified, with 142,577 (95.9%) closed‐ and 6158 (4.1%) open‐type fractures. A total of 106,243 (71.5%) patients were male and the median patient age was 41 years. The majority of patients (79.2%) had abbreviated injury scale scores of ≤2, indicating minor/moderate injury. Fracture mechanism of injury (MOI) differed by gender, with the most frequent being unarmed fights in men (34.3%) and falls in women (14.0%). There were 29,600 patients (19.9%) with isolated orbital floor (I‐OF) fractures. The MOI most strongly associated with operative intervention of with I‐OF fractures were penetrating injuries caused by a firearm (odds ratio [OR]: 2.91; 95% confidence interval [CI]: 1.62–5.20) and cuttings/piercings (OR: 2.17; 95% CI: 1.29–3.65).ConclusionThis large epidemiological study reveals that orbital floor fractures tend to present with minor or moderate injuries and are more likely to require operative intervention in setting of firearm or cut/pierce injuries.
Stationary Creep
Authors: Sandström Rolf 
Published: January 2024

AbstractAn introduction to creep and its main characterstics are given. Stationary creep has been studied extensively in the literature. Stationary creep is a result of a balance between work hardening and recovery processes, which allows for a continues plastic deformation without raising the stress. The starting point for the basic modeling of creep is a differential equation for the dislocation density that describes how it varies with strain or time. The model explains how the dislocation density is influenced by work hardening and recovery. From the dislocation model, a basic equation for the creep rate is derived that is in many respects similar to the classical Bird, Mukherjee and Dorn (BMD) formula but with the values of the parameters given. By taking the role of strain induced vacancies into account, the applicability of the BMD equation is widely expanded because the basic model can also handle low temperatures and high stresses that is usually referred to as the power-law break down regime. It is illustrated that the creep model can represent the creep rate for pure metals such as Al and Ni.
Stress Strain Curves
Authors: Sandström Rolf 
Published: January 2024

AbstractTraditionally, stress strain curves for example from tensile testing are described with empirical models with a number of adjustable parameters such as Hollomon, Ludwik, Voce and Swift. With such models it is difficult or impossible to generalize and extrapolate. A model in the form of Voce equation is derived from the same basic dislocation model used for the creep models with the values of constants computed. The derived model is used to describe stress strain curves for Cu including their temperature and strain rate dependence. The dynamic recovery constant ω plays a central to show how the work hardening deviates from a linear behaviour. The temperature dependence of ω is analyzed and shown to be related to that of the shear modulus. In the literature it is frequently assumed that dynamic recovery is controlled by cross-slip. However, the measured activation energy for dynamic recovery is many times smaller than the energy required to make partial dislocations brought together and form a constriction, which is necessary to enable cross-slip, so this is an unlikely possibility.
Creep with Low Stress Exponents
Authors: Sandström Rolf 
Published: January 2024

AbstractPrimary creep models predict that at low stresses a stress exponent of 1 can be obtained for dislocation creep. Also experimentally this has been observed for an austenitic stainless steel. The time dependence of the primary creep verifies that it is dislocation creep. An other example is for Al at very high temperatures (Harper-Dorn creep), where at sufficiently low stresses, the stress exponent approaches 1. For both materials higher stresses give larger stress exponents as expected for dislocation creep. Obviously, diffusion and dislocation creep can be competing processes. The validity of creep models at low stresses and high temperatures as well as at high stresses and low temperatures demonstrates their wide range of usage. Since this in reality represents an extensive extrapolation, it can be consider as a direct verification of the basic creep models. In cases for Cu and stainless steels, the predicted creep rate by diffusion creep (Coble) exceeds the observed creep rate as well as the predicted one by dislocation creep by an order of magnitude. The likely explanation is that constrained boundary creep is taken place, i.e. the grain boundary creep rate cannot be essentially faster than that of the bulk.
Axion-like particle (ALP) portal freeze-in dark matter confronting ALP search experiments
Authors: Ghosh Dilip Kumar , Ghoshal Anish , Jeesun Sk 
Published: January 2024

Abstract
The relic density of Dark Matter (DM) in the freeze-in scenario is highly dependent on the evolution history of the universe and changes significantly in a non-standard (NS) cosmological framework prior to Big Bang Nucleosynthesis (BBN). In this scenario, an additional species dominates the energy budget of the universe at early times (before BBN), resulting in a larger cosmological expansion rate at a given temperature compared to the standard radiation-dominated (RD) universe. To investigate the production of DM in the freeze-in scenario, we consider both standard RD and NS cosmological picture before BBN and perform a comparative analysis. We extend the Standard Model (SM) particle content with a SM singlet DM particle χ and an axion-like particle (ALP) a. The interactions between ALP, SM particles, and DM are generated by higher dimensional effective operators. This setup allows the production of DM χ from SM bath through the mediation of ALP, via ALP-portal processes. These interactions involve non-renormalizable operators, leading to ultraviolet (UV) freeze-in, which depends on the reheating temperature (TRH) of the early universe. In the NS cosmological scenario, the faster expansion rate suppresses the DM production processes, allowing for enhanced effective couplings between the visible and dark sectors to satisfy the observed DM abundance compared to RD scenario. This improved coupling increases the detection prospects for freeze-in DM via the ALP-portal, which is otherwise challenging to detect in RD universe due to small couplings involved. Using an effective field theory set-up, we show that various ALP searches such as in FASER, DUNE, and SHiP, etc. will be able to probe significant parameter space depending on the different model parameters.
Benzomorphan and non-benzomorphan agonists differentially alter sigma-1 receptor quaternary structure, as does types of cellular stress
Authors: Couly Simon , Yasui Yuko , Foncham Semnyonga , Grammatikakis Ioannis , Lal Ashish , Shi Lei , Su Tsung-Ping 
Published: January 2024

AbstractSigma-1 receptor (S1R) is a calcium-sensitive, ligand-operated receptor chaperone present on the endoplasmic reticulum (ER) membrane. S1R plays an important role in ER-mitochondrial inter-organelle calcium signaling and cell survival. S1R and its agonists confer resilience against various neurodegenerative diseases; however, the molecular mechanism of S1R is not yet fully understood. At resting state, S1R is either in a monomeric or oligomeric state but the ratio of these concentrations seems to change upon activation of S1R. S1R is activated by either cellular stress, such as ER-calcium depletion, or ligands. While the effect of ligands on S1R quaternary structure remains unclear, the effect of cellular stress has not been studied. In this study we utilize cellular and an in-vivo model to study changes in quaternary structure of S1R upon activation. We incubated cells with cellular stressors (H2O2 and thapsigargin) or exogenous ligands, then quantified monomeric and oligomeric forms. We observed that benzomorphan-based S1R agonists induce monomerization of S1R and decrease oligomerization, which was confirmed in the liver tissue of mice injected with (+)-Pentazocine. Antagonists block this effect but do not induce any changes when used alone. Oxidative stress (H2O2) increases the monomeric/oligomeric S1R ratio whereas ER calcium depletion (thapsigargin) has no effect. We also analyzed the oligomerization ability of various truncated S1R fragments and identified the fragments favorizing oligomerization. In this publication we demonstrate that quaternary structural changes differ according to the mechanism of S1R activation. Therefore, we offer a novel perspective on S1R activation as a nuanced phenomenon dependent on the type of stimulus.
Minimization of the Buckling Load of a Clamped Plate with Perimeter Constraint
Authors: Carriero Michele , Cito Simone , Leaci Antonio 
Published: January 2024

AbstractWe look for minimizers of the buckling load problem with perimeter constraint in any dimension. In dimension 2, we show that the minimizing plates are convex; in higher dimension, by passing through a weaker formulation of the problem, we show that any optimal set is open and connected. For the higher eigenvalues, we prove that minimizers exist among convex sets with prescribed perimeter.
Carbonservation with Demonstrated Biodiversity and Carbon Gains: Carbon Can Pay But Biodiversity Must Lead
Authors: Bond Anthelia J. , O’Connor Patrick J. , Cavagnaro Timothy R. 
Published: January 2024

AbstractLand use has a critical role to play in both climate change mitigation and biodiversity conservation, and increasingly there have been calls to integrate policies for concurrently meeting Paris Agreement commitments and the UN decade on ecosystem restoration 2021–2030. Currently however, investment activities have been dominated by climate change mitigation activities, including through the development of carbon markets (both voluntary and compliance markets). Whilst climate change mitigation is to be welcomed, the prioritization of carbon in avoided deforestation and reforestation can lead to suboptimal or negative outcomes for biodiversity. Restoration of degraded native vegetation may provide an opportunity for concurrent production of both carbon and biodiversity benefits, by harnessing existing carbon markets without the need to trade-off biodiversity outcomes. Here we demonstrate that carbon sequestered by restoring degraded temperate woodland can pay the price of the restored biodiversity. This is shown using conservative carbon prices in an established market (during both a voluntary and compliance market phase), and the restoration price revealed by a 10-year conservation incentive payment scheme. When recovery rates are high, market prices for carbon could pay the full price of restoration, with additional independent investment needed in cases where recovery trajectories are slower. Using carbon markets to fund restoration of degraded native vegetation thereby provides a solution for constrained resources and problematic trade-offs between carbon and biodiversity outcomes. Multi-attribute markets offer the potential to greatly increase the extent of restoration for biodiversity conservation, while providing an affordable source of carbon sequestration and enhancing economic benefits to landowners.
Diagnostic management of blastic plasmacytoid dendritic cell neoplasm (BPDCN) in close interaction with therapeutic considerations
Authors: Shumilov Evgenii , Mazzeo Paolo , Ghandili Susanne , Künstner Axel , Weidemann Sören , Banz Yara , Ströbel Philipp , Pollak Matthias , Kolloch Lina , Beltraminelli Helmut , Kerkhoff Andrea , Mikesch Jan-Henrik , Schliemann Christoph , Haase Detlef , Wulf Gerald , Legros Myriam , Lenz Georg , Feldmeyer Laurence , Pabst Thomas , Witte Hanno , Gebauer Niklas , Bacher Ulrike 
Published: January 2024

AbstractBlastic plasmacytoid dendritic cell neoplasm (BPDCN), a rare malignancy derived from plasmacytoid dendritic cells, can mimic both acute leukemia and aggressive T-cell lymphoma. Therapy of this highly aggressive hematological disease should be initiated as soon as possible, especially in light of novel targeted therapies that have become available. However, differential diagnosis of BPDCN remains challenging. This retrospective study aimed to highlight the challenges to timely diagnoses of BPDCN. We documented the diagnostic and clinical features of 43 BPDCN patients diagnosed at five academic hospitals from 2001–2022. The frequency of BPDCN diagnosis compared to AML was 1:197 cases. The median interval from the first documented clinical manifestation to diagnosis of BPDCN was 3 months. Skin (65%) followed by bone marrow (51%) and blood (45%) involvement represented the most common sites. Immunophenotyping revealed CD4 + , CD45 + , CD56 + , CD123 + , HLA-DR + , and TCL-1 + as the most common surface markers. Overall, 86% (e.g. CD33) and 83% (e.g., CD7) showed co-expression of myeloid and T-cell markers, respectively. In the median, we detected five genomic alterations per case including mutational subtypes typically involved in AML: DNA methylation (70%), signal transduction (46%), splicing factors (38%), chromatin modification (32%), transcription factors (32%), and RAS pathway (30%), respectively. The contribution of patients (30%) proceeding to any form of upfront stem cell transplantation (SCT; autologous or allogeneic) was almost equal resulting in beneficial overall survival rates in those undergoing allogeneic SCT (p = 0.0001). BPDCN is a rare and challenging entity sharing various typical characteristics of other hematological diseases. Comprehensive diagnostics should be initiated timely to ensure appropriate treatment strategies.
Connectivity with Uncertainty Regions Given as Line Segments
Authors: Cabello Sergio , Gajser David 
Published: January 2024

AbstractFor a set $${\mathcal {Q}}$$
Q
of points in the plane and a real number $$\delta \ge 0$$

δ
≥
0

, let $${\mathbb {G}}_\delta ({\mathcal {Q}})$$

G
δ

(
Q
)

be the graph defined on $${\mathcal {Q}}$$
Q
by connecting each pair of points at distance at most $$\delta $$
δ
.We consider the connectivity of $${\mathbb {G}}_\delta ({\mathcal {Q}})$$

G
δ

(
Q
)

in the best scenario when the location of a few of the points is uncertain, but we know for each uncertain point a line segment that contains it. More precisely, we consider the following optimization problem: given a set $${\mathcal {P}}$$
P
of $$n-k$$

n
-
k

points in the plane and a set $${\mathcal {S}}$$
S
of k line segments in the plane, find the minimum $$\delta \ge 0$$

δ
≥
0

with the property that we can select one point $$p_s\in s$$

p
s

∈
s

for each segment $$s\in {\mathcal {S}}$$

s
∈
S

and the corresponding graph $${\mathbb {G}}_\delta ( {\mathcal {P}}\cup \{ p_s\mid s\in {\mathcal {S}}\})$$

G
δ

(
P
∪

{

p
s

∣
s
∈
S
}

)

is connected. It is known that the problem is NP-hard. We provide an algorithm to exactly compute an optimal solution in $${{\,\mathrm{{\mathcal {O}}}\,}}(f(k) n \log n)$$

O

(
f
(
k
)
n
log
n
)

time, for a computable function $$f(\cdot )$$

f
(
·
)

. This implies that the problem is FPT when parameterized by k. The best previous algorithm uses $${{\,\mathrm{{\mathcal {O}}}\,}}((k!)^k k^{k+1}\cdot n^{2k})$$

O

(

(
k
!
)

k

k

k
+
1

·

n

2
k

)

time and computes the solution up to fixed precision.