bluuebunny/crossref_metadata_2025_split huggingface dataset:
Autonomous navigation of a non‐holonomic robot for 3D tracking unsteady environmental boundaries
Authors: Matveev Alexey S. , Semakova Anna A. 
Published: March 2021

AbstractAn under‐actuated non‐holonomic robot moves in three dimensions with a constant surge speed and is actuated by upper bounded yawing and pitching rates. The 3D workspace hosts an unknown and time‐varying scalar field. The robot measures only its value at the current location and has no access to the field gradient. Starting from an occasional initial location, the robot should arrive at the level set (isosurface) where the field assumes a predefined value. After this, the robot should repeatedly sweep the entirety of this moving and deforming isosurface. We present a hybrid control law that solves this mission. This law switches among three discrete states, two of which are interchanged on a regular basis, and follows the sliding mode paradigm to drive the robot within a given discrete state. It does not visibly try to estimate the field gradient, is computationally inexpensive, and exhibits a regular, smooth motion. The proposed law is rigorously justified by a global convergence result. Its performance is demonstrated by computer simulation tests.
Sweet Syndrome: A Retrospective Study of 64 Cases and Proposal of an Algorithmic Approach to Improve Investigation and Management
Authors: Gopee N. H. , Charlton F. G. , Hampton P. J. 
Published: March 2021

Abstract

Background
Sweet syndrome (SS) can be categorized as classical Sweet syndrome (CSS), malignancy-associated Sweet syndrome (MASS) or drug-induced Sweet syndrome (DISS). Appropriate categorization of patients with SS and identification of the associated trigger are essential to direct subsequent investigations and follow-up, especially given that 21% of cases are malignancy-associated. However, no published guidelines exist to guide this.

Objective
To analyse the categorization, management and outcomes of patients with SS in order to propose a structured approach for investigation and follow-up.

Methods
Retrospective data collection from the electronic records of patients diagnosed with SS between 1 January 2005 and 31 December 2018. Categorized and non-categorized patients were compared, and the yield rate of investigations and duration of follow-up were analysed.

Results
Sixty-four patients were included with CSS (77%), MASS (20%) and DISS (3%). Of these, 34 (53%) cases were not categorized by the assessing clinicians, three of which were subsequently diagnosed with a malignancy, up to 19 months later. There was no significant difference in investigations performed between categorized and non-categorized patients and the yield rates were modest overall. Follow-up averaged 10.5 (16.8) months; non-categorized patients were followed-up for significantly longer than categorized patients (15.0 (21.2) vs. 5.4 (6.8) months, p &lt; 0.05).

Conclusion
The lack of a structured way to approach patients with SS can lead to under- or over-investigation, diagnostic delays of underlying conditions and unnecessary follow-up. An algorithm is proposed to identify the likely trigger and manage patients accordingly. Larger prospective studies are required to confirm the optimal approach to investigate and follow-up patients with SS.
R&D incentives and competitive pressure under hidden information
Authors: Romano Maria G. 
Published: March 2021

AbstractWithin a principal‐agent model, the paper studies how hidden information affects incentives to invest in demand‐enhancing R&D of a firm competing in the product market. The analysis shows that, when the R&D outcome is private information of the innovating firm not only compared to its competitor, but also relative to its supplier, a contractual cost arises which neutralizes the standard strategic benefit of R&D and reduces the incentives to invest. Moreover, within this setting, more intense competition always stifles innovation.
Mild cognitive impairment and major depressive disorder are associated with molecular senescence abnormalities in older adults
Authors: Diniz Breno S. , Vieira Erica M. , Mendes‐Silva Ana Paula , Bowie Christopher R. , Butters Meryl A. , Fischer Corinne E. , Flint Alastair , Herrmann Nathan , Kennedy James , Lanctôt Krista L. , Mah Linda , Pollock Bruce G. , Mulsant Benoit H. , Rajji Tarek K. ,   on behalf of the PACt‐MD Study Group
Published: March 2021

AbstractIntroductionThe biological mechanisms linking mild cognitive impairment (MCI) and major depressive disorder are not well understood. We investigated whether molecular senescence changes in older adults are associated with a history of major depressive disorder (MDD) or MCI.MethodsWe included 371 participants: 167 with MCI; 62 cognitively normal with a history of MDD; 97 with MDD+MCI; and 45 cognitively unimpaired (CU) without a history of MDD. The candidate Senescence‐Associated Secretory Phenotype (SASP) biomarkers were measured in the plasma using a customized LUMINEX assay.ResultsThe MDD+MCI group had a higher SASP index than the other groups (P < .001). A higher SASP index was significantly associated with worse global cognitive performance, executive dysfunction, slower processing speed, and episodic memory deficits.DiscussionOur study suggests that increased molecular changes are associated with cognitive impairment in older adults with MDD and indicate that accelerated biological aging is an underlying feature of MDD.
Anti‐N‐homocysteine‐protein autoantibodies are associated with impaired cognition
Authors: Włoczkowska Olga , Perła‐Kaján Joanna , Smith A. David , de Jager Celeste , Refsum Helga , Jakubowski Hieronim 
Published: March 2021

AbstractIntroductionElevated homocysteine (Hcy) and related metabolites accelerate Alzheimer's disease. Hcy‐lowering B vitamins slow brain atrophy/cognitive decline in mild cognitive impairment (MCI). Modification with Hcy‐thiolactone generates auto‐immunogenic N‐Hcy‐protein. We tested a hypothesis that anti‐N‐Hcy‐protein autoantibodies predict cognition in individuals with MCI participating in a randomized, double‐blind, placebo‐controlled VITACOG trial of B vitamins.MethodsParticipants with MCI (n = 196, 76.8 years old, 60% women) were randomly assigned to receive a daily dose of folic acid (0.8 mg), vitamin B12 (0.5 mg), and B6 (20 mg) (n = 98) or placebo (n = 98) for 2 years. Cognition was analyzed by neuropsychological tests. Brain atrophy was quantified in a subset of patients (n = 167) by magnetic resonance imaging. Anti N‐Hcy‐protein auto‐antibodies were quantified by enzyme‐linked immunosorbent assay. Associations among anti‐N‐Hcy‐protein autoantibodies, cognition, and brain atrophy were examined by multiple regression analysis.ResultsAt baseline, anti‐N‐Hcy‐protein autoantibodies were significantly associated with impaired global cognition (Mini‐Mental State Examination [MMSE]), episodic memory (Hopkins Verbal Learning Test‐revised), and attention/processing speed (Map Search). At the end of the study, anti‐N‐Hcy‐protein autoantibodies were associated with impaired global cognition (MMSE) and attention/processing speed (Trail Making A). In the placebo group, baseline anti‐N‐Hcy‐protein autoantibodies predicted, independently of Hcy, global cognition (Telephone Inventory for Cognitive Status modified [TICS‐m]; MMSE) and attention/processing speed (Trail Making A) but not brain atrophy, at the end of study. B‐vitamin treatment abrogated association of anti‐N‐Hcy‐protein autoantibodies with cognition.DiscussionThese findings suggest that anti‐N‐Hcy‐protein autoantibodies can impair functional (attention/processing speed and global cognition), but not structural (brain atrophy), aspects of cognition. Anti‐N‐Hcy‐protein autoantibodies are a new factor associated with impaired cognition, which could be ameliorated by B vitamins.
Wind power costs driven by innovation and experience with further reductions on the horizon
Authors: Beiter Philipp , Cooperman Aubryn , Lantz Eric , Stehly Tyler , Shields Matt , Wiser Ryan , Telsnig Thomas , Kitzing Lena , Berkhout Volker , Kikuchi Yuka 
Published: March 2021

AbstractThe costs of wind power have declined to levels on par with or below those of conventional sources in many parts of the world. Wind power has become one of the fastest‐growing sources of new electricity generation. We take stock of wind power cost evolution over the past 20 years, review methodologies commonly used for cost assessment, discuss the potential for continued cost reduction, and identify anticipated cost and value drivers. Our scope includes both onshore and offshore wind technologies. We draw from a vast body of literature on these topics to highlight key trends, approaches, and limitations. Furthermore, we discuss strategies for wind power assets to enhance their marginal economic value to the broader power system and consumers. We identify a myriad of factors that are expected to influence the future cost and value of wind power, including siting, project scale, turbine size, operational synergies, commodity prices, advancements in turbine technologies, enhanced management of the wind resource, and novel control technologies that provide value for the electricity grid. Because the common methods for forecasting future costs each have their own strengths and weaknesses, we find the best insights are elicited from a combination of methods. Overall, researchers and analysts anticipate further sizable cost reductions for onshore and offshore wind. Midrange forecasts for levelized cost of energy in 2050 are generally between $20 and $30/MWh for onshore wind and $40 and $60/MWh for offshore wind, a reduction to approximately half of today's levels. Optimistic forecasts anticipate these levels as early as 2030.This article is categorized under:
Wind Power > Economics and Policy
BPS Quivers of Five-Dimensional SCFTs, Topological Strings and q-Painlevé Equations
Authors: Bonelli Giulio , Del Monte Fabrizio , Tanzini Alessandro 
Published: March 2021

AbstractWe study the discrete flows generated by the symmetry group of the BPS quivers for Calabi–Yau geometries describing five-dimensional superconformal quantum field theories on a circle. These flows naturally describe the BPS particle spectrum of such theories and at the same time generate bilinear equations of q-difference type which, in the rank one case, are q-Painlevé equations. The solutions of these equations are shown to be given by grand canonical topological string partition functions which we identify with $$\tau $$
τ
-functions of the cluster algebra associated to the quiver. We exemplify our construction in the case corresponding to five-dimensional SU(2) pure super Yang–Mills and $$N_f=2$$

N
f

=
2

on a circle.
Microstructural White Matter Alterations in Cognitively Impaired Patients at Early Stages of Multiple Sclerosis
Authors: Schneider Ruth , Matusche Britta , Genç Erhan , Gold Ralf , Bellenberg Barbara , Lukas Carsten 
Published: March 2021

Abstract
Purpose
As conventional quantitative magnetic resonance imaging (MRI) parameters are weakly associated with cognitive impairment (CI) in early multiple sclerosis (MS), we explored microstructural white matter alterations in early MS or clinically isolated syndrome (CIS) comparing patients with or without CI.

Methods
Based on a preceding tract-based spatial statistics analysis (3 Tesla MRI) which contrasted 106 patients with early MS or CIS and 49 healthy controls, diffusion metrics (fractional anisotropy, FA, mean diffusivity, MD) were extracted from significant clusters using an atlas-based approach. The FA and MD were compared between patients with (Ci_P n = 14) and without (Cp_P n = 81) cognitive impairment in a subset of patients who underwent CI screening.

Results
The FA was reduced in Ci_P compared to Cp_P in the splenium of corpus callosum (p = 0.001), right parahippocampal cingulum (p = 0.002) and fornix cres./stria terminalis (0.042), left posterior corona radiata (p = 0.012), bilateral cerebral peduncles, medial lemniscus and in cerebellar tracts. Increased MD was detected in the splenium of corpus callosum (p = 0.01). The CI-related localizations overlapped only partially with MS lesions.

Conclusion
Microstructural white matter alterations at disease onset were detectable in Ci_P compared to Cp_P in known cognitively relevant fiber tracts, indicating the relevance of early treatment initiation in MS and CIS.
The evaluation of Rolimeter, KLT, KiRA and KT-1000 arthrometer in healthy individuals shows acceptable intra-rater but poor inter-rater reliability in the measurement of anterior tibial knee translation
Authors: Runer Armin , Roberti di Sarsina Tommaso , Starke Vasco , Iltchev Alessandra , Felmet Gernot , Braun Sepp , Fink Christian , Csapo Robert 
Published: March 2021

Abstract
Purpose
To assess measurement equivalence, inter- and intra-rater reliability, standard error of measurements (SEM) and false positive measurements (FPM) of four different knee arthrometers (KLT,Karl Storz; KiRA, I + ; KT-1000 MEDmetric Corp; Rolimeter, Aircast) in healthy patients.

Methods
Four different investigators (two advanced (AR) and two beginners (BR)) examined 12 participants with healthy knees at two time points with regards to anterior tibial translation (ATT) and side-to-side difference (SSD). Test equivalence was assessed using the TOST (two-one-sided t test) procedure with ± 1 mm equivalence boundaries. Intraclass correlation coefficients (ICCs) were calculated using two-way mixed effects models. Furthermore, false positive-(SSD > 3 mm) and SEMs were assessed.

Results
A total of 2304 Lachman Tests were performed. Between-rater SSDs were equivalent between AR and BR raters for the Rolimeter only. Inter-rater ICC values (SSD, ATT) were graded as “poor” to “moderate” for all devices. Equivalent test–retest results were observed for all raters using the Rolimeter, KLT and KT-1000, whereas measurement consistency with KiRA was given in the advanced examiners group only. Intra-rater ICC values (Range: SSD, ATT) were graded as “poor” to “moderate” for SSD values and “moderate” to “good” for ATT. SEMs were lowest for the Rolimeter and highest for KiRA. FPM were never obtained with the Rolimeter (0%), twice (2.1%) with the KT-1000, three times (3.1%) with the KLT and 33 times (34.4%) using KiRA.

Conclusion
There is acceptable intra-rater but poor inter-rater reliability with all tested arthrometers. Measures of knee laxity are comparable between Rolimeter, KLT and KT-1000 but higher for KiRA. Clinically, the present study shows that repeated arthrometry measurements should always be performed by the same investigators.
Ag nanoparticles outperform Au nanoparticles for the use as label in electrochemical point-of-care sensors
Authors: Beck Franziska , Horn Carina , Baeumner Antje J. 
Published: March 2021

AbstractElectrochemical immunosensors enable rapid analyte quantification in small sample volumes, and have been demonstrated to provide high sensitivity and selectivity, simple miniaturization, and easy sensor production strategies. As a point-of-care (POC) format, user-friendliness is equally important and most often not combinable with high sensitivity. As such, we demonstrate here that a sequence of metal oxidation and reduction, followed by stripping via differential pulse voltammetry (DPV), provides lowest limits of detection within a 2-min automatic measurement. In exchanging gold nanoparticles (AuNPs), which dominate in the development of POC sensors, with silver nanoparticles (AgNPs), not only better sensitivity was obtained, but more importantly, the assay protocol could be simplified to match POC requirements. Specifically, we studied both nanoparticles as reporter labels in a sandwich immunoassay with the blood protein biomarker NT-proBNP. For both kinds of nanoparticles, the dose-response curves easily covered the ng∙mL−1 range. The mean standard deviation of all measurements of 17% (n ≥ 4) and a limit of detection of 26 ng∙mL−1 were achieved using AuNPs, but their detection requires addition of HCl, which is impossible in a POC format. In contrast, since AgNPs are electrochemically less stable, they enabled a simplified assay protocol and provided even lower LODs of 4.0 ng∙mL−1 in buffer and 4.7 ng∙mL−1 in human serum while maintaining the same or even better assay reliability, storage stability, and easy antibody immobilization protocols. Thus, in direct comparison, AgNPs clearly outperform AuNPs in desirable POC electrochemical assays and should gain much more attention in the future development of such biosensors.
Ultrasonic particle volume fraction profiling: an evaluation of empirical approaches
Authors: Dash Amitosh , Hogendoorn Willian , Poelma Christian 
Published: March 2021

Abstract
We discuss empirical techniques to extract quantitative particle volume fraction profiles in particle-laden flows using an ultrasound transducer. A key step involves probing several uniform suspensions with varying bulk volume fractions from which two key volume fraction dependent calibration parameters are identified: the peak backscatter amplitude (acoustic energy backscattered by the initial layer of the suspension) and the amplitude attenuation rate (rate at which the acoustic energy decays with depth owing to scattering losses). These properties can then be used to reconstruct spatially varying particle volume fraction profiles. Such an empirical approach allows circumventing detailed theoretical models which characterize the interaction between ultrasound and suspensions, which are not universally applicable. We assess the reconstruction techniques via synthetic volume fraction profiles and a known particle-laden suspension immobilized in a gel. While qualitative trends can be easily picked up, the following factors compromise the quantitative accuracy: (1) initial reconstruction errors made in the near-wall regions can propagate and grow along the reconstruction direction, (2) multiple scattering can create artefacts which may affect the reconstruction, and (3) the accuracy of the reconstruction is very sensitive to the goodness of the calibration. Despite these issues, application of the technique to particle-laden pipe flows shows the presence of a core with reduced particle volume fractions in laminar flows, whose prominence reduces as the flow becomes turbulent. This observation is associated with inertia-induced radial migration of particles away from the pipe axis and is observed in flows with bulk volume fractions as high as 0.08. Even transitional flows with low levels of intermittency are not devoid of this depleted core. In conclusion, ultrasonic particle volume fraction profiling can play a key complementary role to ultrasound-based velocimetry in studying the internal features of particle-laden flows.

Graphic abstract
Near-critical 2D percolation with heavy-tailed impurities, forest fires and frozen percolation
Authors: van den Berg Jacob , Nolin Pierre 
Published: March 2021

AbstractWe introduce a new percolation model on planar lattices. First, impurities (“holes”) are removed independently from the lattice. On the remaining part, we then consider site percolation with some parameter p close to the critical value $$p_c$$

p
c

. The mentioned impurities are not only microscopic, but allowed to be mesoscopic (“heavy-tailed”, in some sense). For technical reasons (the proofs of our results use quite precise bounds on critical exponents in Bernoulli percolation), our study focuses on the triangular lattice. We determine explicitly the range of parameters in the distribution of impurities for which the connectivity properties of percolation remain of the same order as without impurities, for distances below a certain characteristic length. This generalizes a celebrated result by Kesten for classical near-critical percolation (which can be viewed as critical percolation with single-site impurities). New challenges arise from the potentially large impurities. This generalization, which is also of independent interest, turns out to be crucial to study models of forest fires (or epidemics). In these models, all vertices are initially vacant, and then become occupied at rate 1. If an occupied vertex is hit by lightning, which occurs at a very small rate $$\zeta $$
ζ
, its entire occupied cluster burns immediately, so that all its vertices become vacant. Our results for percolation with impurities are instrumental in analyzing the behavior of these forest fire models near and beyond the critical time (i.e. the time after which, in a forest without fires, an infinite cluster of trees emerges). In particular, we prove (so far, for the case when burnt trees do not recover) the existence of a sequence of “exceptional scales” (functions of $$\zeta $$
ζ
). For forests on boxes with such side lengths, the impact of fires does not vanish in the limit as $$\zeta \searrow 0$$

ζ
↘
0

. This surprising behavior, related to the non-monotonicity of these processes, was not predicted in the physics literature.
Micro-CT evaluation of historical human skulls presenting signs of syphilitic infection
Authors: Fraberger Sabine , Dockner Martin , Winter Eduard , Pretterklieber Michael , Weber Gerhard W. , Teschler-Nicola Maria , Pietschmann Peter 
Published: March 2021

Summary
Background
In tertiary syphilis, Treponema pallidum triggers the formation of granulomatous nodules in various organs of the human body. Within the skeleton, predominantly in the skull and long bones, these characteristic syphilitic lesions cause typical patterns of bone damage. In this study, micro-computed tomography (µ-CT) was used to assess the microarchitecture of these osseous defects in untreated syphilitic skull bones.

Material and methods
Bone structure of 30 macerated human skulls was noninvasively examined by means of µ-CT images (Viscom X8060 NDT). A total of 20 specimens showing typical morphological signs of syphilis were provided by the Collection of Anatomical Pathology of the Museum of Natural History in Vienna. They were compared to 10 macerated control skulls provided by the Division of Anatomy of the Medical University of Vienna.

Results
All samples affected by syphilis showed perforating defects and increased porosity. Furthermore, we observed sclerotic reorganization and complete loss of the cortical bone in 80% of infected cases. Cortical thinning occurred in 75%.

Conclusion
Our findings revealed extensive micromorphological bone destruction and a broad variability of osseous manifestations of (tertiary) syphilis.