Profile Alignment Research Articles

Predicting the wear on the non-working side of the rail profile registration method and its validation

Abstract Rail cross-section profile detection can assess the wear and tear of measured rails, providing crucial references for railway maintenance and upkeep. It is challenging to use the conventional method to register only the profile of rail head detection accurately. After the rail edge adjustment in some conventional railways, it becomes difficult to determine the base point of rail profile registration. Due to the wear of non-working edge of rail, a rail profile registration method is proposed. Firstly, a wear prediction model based on the generalized regression neural network is constructed by optimizing smoothing parameters through ten-fold cross-validation to achieve the optimal values. This model predicts the wear values on the non-working rail edge, providing reliable coordinates for two wear points as alignment reference points. Secondly, an initial alignment between the measured profile and the target profile is achieved using the nearest point iterative algorithm, which ensures that both profiles are in the same region and oriented similarly. Thirdly, the weight is assigned to the wear measurement points based on their respective wear values. The predicted positions of wear points are applied for calculating the translation and rotation parameters. These parameters could align the measured profile and facilitate the final profile alignment. Lastly, the experimental profiles under rail adjustment conditions were registered, verifying the accuracy of the proposed method. The research results indicate that under rail adjustment conditions, the mean squared error (MSE) between the calculated and actual values of lateral wear is 0.094 mm2, which is lower than the MSE from manual measurements. The calculated lateral wear value for experimental profiles achieved high alignment and calculation accuracy. This method can be applied in practical projects, providing an effective solution for rail head profile alignment and serving as a reference for profile alignment on the non-working rail edge with incomplete measurement data.

VOGDB-Database of Virus Orthologous Groups.

Computational models of homologous protein groups are essential in sequence bioinformatics. Due to the diversity and rapid evolution of viruses, the grouping of protein sequences from virus genomes is particularly challenging. The low sequence similarities of homologous genes in viruses require specific approaches for sequence- and structure-based clustering. Furthermore, the annotation of virus genomes in public databases is not as consistent and up to date as for many cellular genomes. To tackle these problems, we have developed VOGDB, which is a database of virus orthologous groups. VOGDB is a multi-layer database that progressively groups viral genes into groups connected by increasingly remote similarity. The first layer is based on pair-wise sequence similarities, the second layer is based on the sequence profile alignments, and the third layer uses predicted protein structures to find the most remote similarity. VOGDB groups allow for more sensitive homology searches of novel genes and increase the chance of predicting annotations or inferring phylogeny. VOGD B uses all virus genomes from RefSeq and partially reannotates them. VOGDB is updated with every RefSeq release. The unique feature of VOGDB is the inclusion of both prokaryotic and eukaryotic viruses in the same clustering process, which makes it possible to explore old evolutionary relationships of the two groups. VOGDB is freely available at vogdb.org under the CC BY 4.0 license.

Organic solar cell efficiency improvement through architecture engineering by integrating carbon nanoring – SCAPS 1D modelling

This research work aims to investigate on improving the performance of organic solar cells (OSC) by proposing new architectures that progressively integrate carbon nanotubes. This contribution takes into account the exceptional properties of carbon nanotubes (CNT) highlighted in recent work, with the aim of addressing the current challenges of materials used in the manufacture of conventional OSCs, such as reactivity with the ambient medium, stability over time, better transport of charge carriers, etc. Using a reference OSC cell with the following structure: PEDOT/BHJ/PDINO and the numerical one-dimensional simulation tool SCAPS, which helps in validating the modelling approach, we gradually replace each layer with a CNT-based material exhibiting superior properties. In this respect, we carry out calculations on the different cells architectures, to better visualize energy-level alignment profiles, the different current-voltage (J-V), and quantum efficiency (QE) characteristics. Approaches toward efficiency improvement were discussed, by investigating the effects of active layer thickness, the doping level, the charge carriers mobility, defect density, and external parameters such as temperature. After numerous calculations and modelling, very promising results were finally achieved with a full CNT-based solar structure with the following recorded performances: VOC=0.87V, JSC=27.81mA/cm2, FF=80.91%, and PCE=19.63%. These results are the first theoretical report for a complete CNT-based modelled OSC and, given the reliability and robustness of the approach adopted, they can be considered as relevant for future theoretical and experimental work. The integration of CNT as functional layers is a remarkable step forward in OSC architectures engineering for efficiency enhancement. CNT are good candidates for light harvesting applications.

Geometric Improvements in the Horizontal Alignment and Vertical Profile of Lohapathar Ghat Section in Bhopal-Salkanpur Road using Autodesk Civil 3D Software

Geometric Improvements in the Horizontal Alignment and Vertical Profile of Lohapathar Ghat Section in Bhopal-Salkanpur Road using Autodesk Civil 3D Software

Restoring L4-S1 Lordosis Shape in Severe Sagittal Deformity: Impact of Correction Techniques on Alignment and Complication Profile

Severe sagittal plane deformity with loss of L4-S1 lordosis is disabling and can be improved through various surgical techniques. However, data is limited on the differing ability of anterior lumbar interbody fusion (ALIF), pedicle subtraction osteotomy (PSO), and transforaminal lumbar interbody fusion (TLIF) to achieve alignment goals in severely malaligned patients. To examine surgical techniques aimed at restoring L4-S1 lordosis in severe adult spinal deformity (ASD). Retrospective review of prospectively collected data. A total of 96 patients who underwent ALIF, PSO, and TLIF were included in this study. The following data were observed for all cases: patient demographics, spinopelvic parameters, complications, and PROMs. Severe ASD patients with preoperative PI-LL >20°, L4-S1 lordosis <30°, and full body radiographs and patient-reported outcome measures (PROMs) at baseline and six-week postoperative visit were included. Patients were grouped into ALIF (1-2 level ALIF at L4-S1), PSO (L4/L5 PSO), and TLIF (1-2 level TLIF at L4-S1). Comparative analyses were performed on demographics, radiographic spinopelvic parameters, complications, and PROMs. Among the 96 included patients, 40 underwent ALIF, 27 underwent PSO, and 29 underwent TLIF. At baseline, cohorts had comparable age, sex, race, Edmonton frailty scores and radiographic spinopelvic parameters (p>0.05). However, PSO was performed more often in revision cases (p<0.001). Following surgery, L4-S1 lordosis correction (p=0.001) was comparable among ALIF and PSO patients and caudal lordotic apex migration (p=0.044) was highest among ALIF patients. PSO patients had higher intraoperative estimated blood loss (p<0.001) and motor deficits (p=0.049), and in-hospital ICU admission (p=0.022) and blood products given (p=0.004) but were otherwise comparable in terms of length of stay, blood transfusion given, and postoperative admission to rehab. Likewise, 90-day postoperative complication profiles and six-week PROMs were comparable as well. ALIF can restore L4-S1 sagittal alignment as powerfully as PSO, with fewer intra-operative and in-hospital complications. When feasible, ALIF is a suitable alternative to PSO and likely superior to TLIF for correcting L4-S1 lordosis among patients with severe sagittal malalignment.

Inverse kinematic total knee arthroplasty using conventional instrumentation restores constitutional coronal alignment.

Restricted inverse kinematic alignment (iKA) is a contemporary alignment strategy for total knee arthroplasty (TKA), commonly performed with robotic assistance. While superior clinical results are reported for kinematic-type alignment strategies, registry data indicate no survivorship benefit for navigation or robotic assistance. This study aimed to determine the efficacy of an instrumented, restricted iKA technique for achieving patient-specific alignment. Seventy-nine patients undergoing 84 TKAs (five bilateral procedures) using an iKA technique were included for preoperative and postoperative lower limb alignment analysis. The mean age was 66.5 (range: 43-82) with 33 male and 51 female patients. Artificial intelligence was employed for radiographic measurements. Alignment profiles were classified using the Coronal Plane Alignment of the Knee (CPAK) system. Preoperative and postoperative alignment profiles were compared with subanalyses for preoperative valgus, neutral and varus profiles. The mean joint-line convergence angle (JLCA) reduced from 2.5° to -0.1° postoperatively. The mean lateral distal femoral angle (LDFA) remained unchanged postoperatively, while the mean medial proximal tibial angle (MPTA) increased by 2.5° (p = 0.001). By preservation of the LDFA and restoration of the MPTA, the mean hip knee ankle angle (HKA) moved through 3.5° varus to 1.2° valgus. The CPAK system was used to visually depict changes in alignment profiles for preoperative valgus, neutral and varus knees; with 63% of patients observing an interval change in classification. Encouraged by the latest evidence supporting both conventional instrumentation and kinematic-type TKA strategies, this study describes how a restricted, conventionally instrumented iKA technique may be utilised to restore constitutional lower limb alignment. Level III.

SUBSTANTIATION OF METHOD FOR LEVELING INJECTIVITY PROFILE UNDER CONDITIONS OF CARBONATE RESERVOIRS OF FIELD NAMED AFTER R. TREBSA

At the moment, the issue of reducing water cut during the development of carbonate fractured reservoirs is relevant. In the work, the object of the study is the carbonate deep reservoirs of the R. Trebs field. According to the field development analysis, there are production wells with sharp unpredictable breakthrough of injected water.In order to increase the coverage of pay zones by waterflooding, it is necessary to use methods aimed at limiting the filtration of injected water into water-flooded intervals.High formation temperature and mineralization of formation water are complicating factors in the selection of the injection profile alignment (runway) technology.Taking into account the criteria specified in the work, potential candidates for testing the technology were selected for the runway.The article analyzed the advantages and disadvantages of the existing runway methods used when exposed to injection wells. The criteria for the applicability of various technologies based on the use of: polymer/gel compositions, emulsion compositions, including reverse emulsions, injection of aqueous salt solutions, silicate, thermotropic and complex reagents are highlighted. Technologies and compositions based on water-soluble polymers that form viscoelastic compositions when crosslinkers of various nature are added are recognized as the most promising for the conditions of the fractured reservoir of the Trebs field.Particular attention is paid to laboratory experiments aimed at studying the physical and chemical properties of crosslinked polymer systems, conducting filtration experiments, determining the applicability of the technology for the geological and physical conditions of the study object.According to the results of physicochemical experiments, such parameters as the time of dissolution of reagents, compatibility with formation water, time and temperature of gelling were determined. Based on the shear test, rheological parameters of the investigated polymer systems are determined. Testing was carried out to determine the conditions under which the crosslinked polymer composition breaks down.Filtration experiments were carried out on linear and volumetric models of the formation using core material from the Trebs field to determine the reagent with the highest colmating abilities calculated from the residual resistance factor.

HR Automation: Enhancing Candidate Onboarding Processes

Human Resources (HR) departments are faced with the problem of effectively managing a variety of activities, from talent acquisition to legal compliance, in the dynamic workforce landscape of today. This study explores the ground breaking integration of Artificial Intelligence (AI), with an emphasis on Natural Language Processing (NLP), as a transformative force in reimagining Human Resources (HR) management methodologies." The pivotal role of two cutting-edge AI tools, the Legal Language Model (LLM) and the Language Model for Attribute-based Matching (LAMA), is examined in addressing key HR challenges. LLM employs sophisticated NLP techniques to automate and refine the interpretation of complex legal documents, ensuring compliance and reducing legal risks. Concurrently, LAMA transforms the recruitment paradigm by facilitating a nuanced, attribute-based alignment of candidates' profiles with job requirements, thereby optimizing the talent acquisition process. We explore the integration of these models within an interactive framework provided by Streamlit, a Python tool for creating user-engaging web applications. This integration offers HR professionals an intuitive platform for accessing, visualizing, and interacting with model-generated insights, fostering informed decision-making and enhanced operational efficiency. Our analysis reveals significant improvements in the precision of recruitment processes, efficacy in legal document handling, and overall workflow streamlining. The findings advocate for the adoption of these AI-driven tools in HR, highlighting their potential to revolutionize traditional practices and contribute to the strategic growth of organizations in the contemporary digital landscape. Key Words: Human Resources Management, Legal Language Model (LLM), Language Model for Attribute-based Matching (LAMA), Streamlit, HR Technology Integration, HR Automation.

Development of a competency framework for advanced practice nurses: A co-design process.

The aim of the study was to develop a comprehensive competency framework for advanced practice nurses in Belgium. A co-design development process was conducted. This study consisted of two consecutive stages (November 2020-December 2021): (1) developing a competency framework for advanced practice nurses in Belgium by the research team, based on literature and (2) group discussions or interviews with and written feedback from key stakeholders. 11 group discussions and seven individual interviews were conducted with various stakeholder groups with a total of 117 participants. A comprehensive competency framework containing 31 key competencies and 120 enabling competencies was developed based on the Canadian Medical Education Directions for Specialists Competency Framework. These competencies were grouped into seven roles: clinical expert and therapist, organizer of quality care and leader in innovation, professional and clinical leader, collaborator, researcher, communicator and health promoter. The developed competency framework has resemblance to other international frameworks. This framework emphasized the independent role of the advanced practice nurse and provided guidance in a clear task division and delegation to other professionals. It can provide a solid foundation for delivering high-quality, patient-centred care by advanced practice nurses in the years to come. This competency framework can guide further development of advanced practice nursing education in Belgium and represents a starting point for future evaluation of its feasibility and usability in education and clinical practice. Advanced practice nurses and healthcare managers can also use the framework as an instrument for personal and professional development, performance appraisal, and further alignment of these function profiles in clinical practice. Finally, this framework can inform and guide policymakers towards legal recognition of advanced practice nursing in Belgium and inspire the development of advanced practice nursing profiles in countries where these profiles are still emerging. What problem did the study address? The absence of a detailed competency framework for advanced practice nurses complicates legal recognition, role clarification and implementation in practice in Belgium. A rigorously developed competency framework could clarify which competencies to integrate in future advanced practice nursing education, mentorship programs and practice. What were the main findings? The competency framework outlined seven roles for advanced practice nurses: clinical expert and therapist, organizer of quality care and leader in innovation, professional and clinical leader, collaborator, researcher, communicator, and health promoter. Differentiation from other expert nursing profiles and clinical autonomy of advanced practice nurses were pivotal. Where and on whom will the research have impact? The comprehensive competency framework for advanced practice nurses and the collaborative methodology used can inspire other countries where these profiles are still emerging. The competency framework can be used as an instrument for role clarification, performance appraisals, continuous professional development, and professional (e-)portfolios. The competency framework can guide policymakers when establishing Belgian's legal framework for advanced practice nurses. The authors have adhered to CONFERD-HP: recommendations for reporting COmpeteNcy FramEwoRk Development in health professions. No patient or public contribution in the design of the study. A patient advisory panel commented on the developed competency framework.

Dynamic rail wear measurement: integration of RTK GNSS, IMU, and laser

Currently, laser sensors are widely utilized in railway systems for monitoring rail wear. However, the lack or insufficiency of rail waist data poses a challenge to accurately match profiles and calculate wear. In this paper, we propose a novel approach for dynamic rail wear monitoring that comprises three major modules: a filtering methodology to smooth rail profile data, fine compensation to calibrate the angle distortion, and fast profile alignment. Initially, the AF technique and Kalman filter are applied to reconstruct the profile. This is followed by integrating real-time kinematic global navigation satellite system, inertial measurement unit, and laser to precisely correct the rail profile dynamic distortion. Additionally, genetic algorithms-least squares method is used for rapid determination of the R20mm center of the profile. Rigorous testing and trials have demonstrated that our proposed approach achieves precision as low as 0.03 mm with significant potential in dynamic rail wear monitoring.

Q&amp;A of liquid crystal alignment: theory and practice

We selected and summarized the most important aspects of liquid crystal alignment. Alignment by the surface profile and flat surface alignment are discussed as the main factors leading to the high-quality orientation of liquid crystals. The advanced level of understanding and formulation allows linking the alignment layer properties to the molecular structure of the alignment material. The paper reviews and combines the latest knowledge about liquid crystal alignment, dwells upon the relationship between the polar and azimuthal anchoring energy, explains the major particularities regarding anchoring measurements in the case of birefringent alignment materials with truly high azimuthal anchoring energy, and observes the current trends of water-friendly alignment materials and their application in geometrical phase device fabrication.

Comparative Genome Annotation.

Newly sequenced genomes are being added to the tree of life at an unprecedented fast pace. A large proportion of such new genomes are phylogenetically close to previously sequenced and annotated genomes. In other cases, whole clades of closely related species or strains ought to be annotated simultaneously. Often, in subsequent studies, differences between the closely related species or strains are in the focus of research when the shared gene structures prevail. We here review methods for comparative structural genome annotation. The reviewed methods include classical approaches such as the alignment of protein sequences or protein profiles against the genome and comparative gene prediction methods that exploit a genome alignment to annotate either a single target genome or all input genomes simultaneously. We discuss how the methods depend on the phylogenetic placement of genomes, give advice on the choice of methods, and examine the consistency between gene structure annotations in an example. Furthermore, we provide practical advice on genome annotation in general.

The circularly permuted globin domain of androglobin exhibits atypical heme stabilization and nitric oxide interaction.

In the decade since the discovery of androglobin, a multi-domain hemoglobin of metazoans associated with ciliogenesis and spermatogenesis, there has been little advance in the knowledge of the biochemical and structural properties of this unusual member of the hemoglobin superfamily. Using a method for aligning remote homologues, coupled with molecular modelling and molecular dynamics, we have identified a novel structural alignment to other hemoglobins. This has led to the first stable recombinant expression and characterization of the circularly permuted globin domain. Exceptional for eukaryotic globins is that a tyrosine takes the place of the highly conserved phenylalanine in the CD1 position, a critical point in stabilizing the heme. A disulfide bond, similar to that found in neuroglobin, forms a closed loop around the heme pocket, taking the place of androglobin's missing CD loop and further supporting the heme pocket structure. Highly unusual in the globin superfamily is that the heme iron binds nitric oxide as a five-coordinate complex similar to other heme proteins that have nitric oxide storage functions. With rapid autoxidation and high nitrite reductase activity, the globin appears to be more tailored toward nitric oxide homeostasis or buffering. The use of our multi-template profile alignment method to yield the first biochemical characterisation of the circularly permuted globin domain of androglobin expands our knowledge of the fundamental functioning of this elusive protein and provides a pathway to better define the link between the biochemical traits of androglobin with proposed physiological functions.

CuO/ZnO catalysts in chitosan film for CO2 reduction

In this work, ZnO of 1.1 and 10.2 nm sizes, respectively, were synthesized by irradiating femtosecond pulse laser in aqueous Zn ion precursor solutions at pH 5.5 and 10.2 in comparison with ZnO of 18.1 nm size prepared by hydrothermal procedure in an alkaline condition. The 12.8 nm CuO synthesized by precipitation method was physically mixed with ZnO, and the nanocomposites were embedded in chitosan (CS) film. Based on the catalytic activity of CuO/ZnO nanocomposite in CS film, the photocatalysis was performed for CO2 gas adsorbed on amine group in CS acting as a CO2 absorber. On the photocatalytic reaction under UV irradiation, the production of methanol was quantified using a chromogenic reagent, sodium nitroprusside. The highest catalytic activity (5642 μmol/g(catalyst)) for the CO2 conversion was achieved on CuO/ZnO/CS film, where ZnO was synthesized at pH 10.2 by femtosecond laser irradiation. The energy level alignment profile proposed the best hole transition from ZnO to CuO on CuO/ZnO/CS film in consistence with the best catalytic activity. Then the ecofriendly film-type system consisting of CS will be focused as promising biocompatible reactors because of facile production procedure and easy catalytic treatment.

A Comparison of Mutual Information, Linear Models and Deep Learning Networks for Protein Secondary Structure Prediction

Background: Over the last several decades, predicting protein structures from amino acid sequences has been a core task in bioinformatics. Nowadays, the most successful methods employ multiple sequence alignments and can predict the structure with excellent performance. These predictions take advantage of all the amino acids at a given position and their frequencies. However, the effect of single amino acid substitutions in a specific protein tends to be hidden by the alignment profile. For this reason, single-sequence-based predictions attract interest even after accurate multiple-alignment methods have become available: the use of single sequences ensures that the effects of substitution are not confounded by homologous sequences. Objective: This work aims at understanding how the single-sequence secondary structure prediction of a residue is influenced by the surrounding ones. We aim at understanding how different prediction methods use single-sequence information to predict the structure. Methods: We compare mutual information, the coefficients of two linear models, and three deep learning networks. For the deep learning algorithms, we use the DeepLIFT analysis to assess the effect of each residue at each position in the prediction. Result: Mutual information and linear models quantify direct effects, whereas DeepLIFT applied on deep learning networks quantifies both direct and indirect effects. Conclusion: Our analysis shows how different network architectures use the information of single protein sequences and highlights their differences with respect to linear models. In particular, the deep learning implementations take into account context and single position information differently, with the best results obtained using the BERT architecture.

Improvements in the Horizontal Alignment and Vertical Profile of Balampur Ghat Section in Bhopal-Vidisha State Highway Road (SH-18) using MXRoad Software

Abstract: Geometric design of highway deals with designing of physical visible features of highway those comprise of horizontal alignment, vertical profile, circular and transition curves, superelevation, Summit and valley curves, cross sectional elements, sight distances and other features. From the safety point of view, road geometric features should be well designed as per the IRC recommendation. In this research work, the horizontal alignment and vertical profile have designed of Balampur Ghat section in the Bhopal-Vidisha Road which is in the Madhya Pradesh State of India. The objective of this research work is “Improvements in the Horizontal alignment and Vertical profile of Balampur Ghat Section in Bhopal-Vidisha State Highway Road (SH-18) using MX Road Software”. The design of horizontal alignment and vertical profile have been done for Balampur ghat section approx. 2.0 km in length of State highway no. 18 (SH-18) of Madhya Pradesh. SH-18 is connected to Vidisha from Bhopal in the state of Madhya Pradesh and having heavy commercial traffic. Balampur ghat section is hilly terrain and have two improper horizontal curves along with 6.5% of vertical gradient and because of this reason that section is not safe for deriving therefore it has become an accident-prone area and the accident-prone area have the human and economical losses so it should be improved and re design of the horizontal and vertical alignment for safe design speed. The proposed methodology is on the basis of inventory survey (preliminary survey), topographic survey and MX Road software. In inventory survey take the data of existing road and find the suitable route of alternative alignment if re-alignment is required in the road. Then the topographic survey done on the existing road and alternative alignment. Import the topographic data of the road in MX Road software for generate existing surface of the road for design of horizontal alignment and vertical profile. As per IRC recommendations, there are two alternative alignments designed of the existing ghat section. As per the outputs of this research work, the length of both improved alignments is short as compare to existing road. There are no improper curves at improved alignment and maximum gradient is 4.2% which is less than the existing gradient (6.5%). The minimum design speed is 40-50 kmph which was 20 kmph in existing road. The both two improved alignments are safer as compare to existing alignment and the design speed of the vehicle has been increased. The improved alignment 2 is straighter than the improved alignment The improved alignment has also reduced the human and economic losses.

Changes in Parameters after High Tibial Osteotomy: Comparison of EOS System and Computed Tomographic Analysis.

Unintended rotation of the distal tibia occurs during medial open-wedge high tibial osteotomy (MOWHTO). Computed tomography (CT) is the standard method of measuring lower limb alignment; however, the new low-dose EOS system allows three-dimensional limb modeling with automated measurements of lower limb alignment. This study investigated the differences between the changes in lower limb alignment profiles obtained using the EOS system and CT in patients who underwent MOWHTO. We investigated whether any factors contributed to the degree of deformation. Thirty patients were prospectively enrolled between October 2019 and February 2023. Changes in femoral and tibial torsion, femorotibial rotation, and posterior tibial slope were measured using pre- and post-MOWHTO CT and EOS images. We found no significant difference in pre- and postoperative tibial torsion or posterior tibial slope between CT and EOS. No variables showed a significant correlation with changes in the tibial torsion or posterior tibial slope. This study confirmed the possibility that the EOS system could replace CT in measuring changes in several parameters pre- and postoperatively. Furthermore, we confirmed that the distal tibia tended to be internally rotated after MOWHTO; however, we found no significantly related parameters related to deformation caused by MOWHTO.

Dynamic time warping to quantify age distortion in firn cores impacted by melt processes

Abstract As warming intensifies across the Greenland ice sheet, an increasing number of shallow coring and radar studies are targeting the melt-impacted firn column to investigate meltwater processes. Highly inhomogeneous infiltration and refreezing, however, redistributes mass, distorting age–depth relationships and confounding comparisons between different cores. Here, we utilize a dynamic time warping algorithm for time series alignment to investigate and quantify the heterogeneous impact of melt processes on nine closely spaced (within 50 m) firn core-density profiles. The 10 m cores were collected relatively high in Greenland's percolation zone, where melt alteration is minimal compared to lower elevation. Our analysis demonstrates the effectiveness of dynamic time warping as a tool for assessing heterogeneity between ice core records. We find that the optimal alignment of density profiles in the nine cores requires vertical stretching and compression of individual profiles, ranging from, on average, &lt;1 to ~16% of the core lengths. We identified four depth zones of mass redistribution that appear to coincide with observed ice layers. Further, ~75% of density measurements from each core do not align with an age model-derived density profile that assumes no mass redistribution of meltwater, indicating the pervasive impact of melt processes.

Multiwavelength observations of PSR J2021+4026 across a mode change reveal a phase shift in its X-ray emission

Context. We have investigated the multiwavelength emission of PSR J2021+4026, the only isolated γ-ray pulsar known to be variable, which in October 2011 underwent a simultaneous change in γ-ray flux and spin-down rate, followed by a second mode change in February 2018. Multiwavelength monitoring is crucial to understand the physics behind these events and how they may have affected the structure of the magnetosphere. Aims. The monitoring of pulse profile alignment is a powerful diagnostic tool for constraining magnetospheric reconfiguration. We aim to investigate timing or flux changes related to the variability of PSR J2021+4026 via multiwavelength observations, including γ-ray observations from Fermi-LAT, X-ray observations from XMM-Newton, and a deep optical observation with the Gran Telescopio Canarias. Methods. We performed a detailed comparison of the timing features of the pulsar in γ and X-rays and searched for any change in phase lag between the phaseogram peaks in these two energy bands. Although previous observations did not detect a counterpart in visible light, we also searched for optical emission that might have increased due to the mode change, making this pulsar detectable in the optical. Results. We have found a change in the γ-to X-ray pulse profile alignment by 0.21 ± 0.02 in phase, which indicates that the first mode change affected different regions of the pulsar magnetosphere. No optical counterpart was detected down to g′ = 26.1 and r′ = 25.3. Conclusions. We suggest that the observed phase shift could be related to a reconfiguration of the connection between the quadrupole magnetic field near the stellar surface and the dipole field that dominates at larger distances. This is consistent with the picture of X-ray emission coming from the heated polar cap and with the simultaneous flux and frequency derivative change observed during the mode changes.

From two sensors to a single sensor: Better understanding of oxygen–sulfide interfaces

AbstractIntense biogeochemical transformations in sediments and biofilms may occur over sub‐mm distances. Our current understanding of those transformations in such narrowly stratified environments has been facilitated by the introduction of microsensors. Until now most studies have been conducted using individual sensors for the various chemical species, and careful vertical alignment of the sensor tips is then essential for the meaningful interpretation of the resulting data. For instance, the determination of total dissolved sulfide (TDS) at high resolution requires perfect alignment of sensors for H2S and pH, as the pKa for H2S is close to ambient pH. In this study, we show how a recently developed TDS sensor and a new combined H2S/O2microsensor can improve the analysis of sulfidic environments including the oxygen–sulfide interface. The TDS sensor does not require pH correction unlike the conventional H2S sensor, and it thus eliminates the need for a simultaneous pH measurement. The combined sensor allows for perfect alignment of H2S and O2micro profiles and makes it possible to not only more accurately estimate fluxes, but also to determine overlapping zones of oxygen and dissolved sulfide at very high resolution.