bluuebunny/crossref_metadata_2025 huggingface dataset:
First look at the giant radio galaxy 3C 236 with LOFAR
Authors: Shulevski A. , Barthel P. D. , Morganti R. , Harwood J. J. , Brienza M. , Shimwell T. W. , Röttgering H. J. A. , White G. J. , Callingham J. R. , Mooney S. , Rafferty D. A.
Published: August 2019

We have examined the giant radio galaxy3C 236using LOFAR at 143 MHz down to an angular resolution of 7″, in combination with observations at higher frequencies. We used the low frequency data to derive spectral index maps with the highest resolution yet at these low frequencies. We confirm a previous detection of an inner hotspot in the north-west lobe and for the first time observe that the south-east lobe hotspot is in fact a triple hotspot, which may point to an intermittent source activity. Also, the spectral index map of3C 236shows that the spectral steepening at the inner region of the northern lobe is prominent at low frequencies. The outer regions of both lobes show spectral flattening, in contrast with previous high frequency studies. We derive spectral age estimates for the lobes, as well as particle densities of the IGM at various locations. We propose that the morphological differences between the lobes are driven by variations in the ambient medium density as well as the source activity history.
Survey of gravitationally-lensed objects in HSC imaging (SuGOHI)
Authors: Sonnenfeld Alessandro , Jaelani Anton T. , Chan James , More Anupreeta , Suyu Sherry H. , Wong Kenneth C. , Oguri Masamune , Lee Chien-Hsiu
Published: August 2019

Context.The determination of the stellar initial mass function (IMF) of massive galaxies is one of the open problems in cosmology. Strong gravitational lensing is one of the few methods that allow us to constrain the IMF outside of the Local Group.

Aims.The goal of this study is to statistically constrain the distribution in the IMF mismatch parameter, defined as the ratio between the true stellar mass of a galaxy and that inferred assuming a reference IMF, of massive galaxies from the Baryon Oscillation Spectroscopic Survey (BOSS) constant mass (CMASS) sample.

Methods.We took 23 strong lenses drawn from the CMASS sample, measured their Einstein radii and stellar masses using multi-band photometry from the Hyper Suprime-Cam survey, then fitted a model distribution for the IMF mismatch parameter and dark matter halo mass to the whole sample. We used a prior on halo mass from weak lensing measurements and accounted for strong lensing selection effects in our model.

Results.Assuming a Navarro Frenk and White density profile for the dark matter distribution, we infer a valueμIMF = −0.04 ± 0.11 for the average base-10 logarithm of the IMF mismatch parameter, defined with respect to a Chabrier IMF. A Salpeter IMF is in tension with our measurements.

Conclusions.Our results are consistent with a scenario in which the region of massive galaxies where the IMF normalisation is significantly heavier than that of the Milky Way is much smaller than the scales 5 − 10 kpc probed by the Einstein radius of the lenses in our sample, as recent spatially-resolved studies of the IMF in massive galaxies suggest.
Observations on spatial variations of the Sr I 4607 Å scattering polarization signals at different limb distances with ZIMPOL
Authors: Dhara Sajal Kumar , Capozzi Emilia , Gisler Daniel , Bianda Michele , Ramelli Renzo , Berdyugina Svetlana , Alsina Ernest , Belluzzi Luca
Published: August 2019

Context. The Sr I 4607 Å spectral line shows one of the strongest scattering polarization signals in the visible solar spectrum. The amplitude of this polarization signal is expected to vary at granular spatial scales, due to the combined action of the Hanle effect and the local anisotropy of the radiation field. Observing these variations would be of great interest because it would provide precious information on the small-scale activity of the solar photosphere. At present, few detections of such spatial variations have been reported. This is due to the difficulty of these measurements, which require combining high spatial (∼0.1″), spectral (≤20 mÅ), and temporal resolution (< 1 min) with increased polarimetric sensitivity (∼10−4).

Aims. We aim to detect spatial variations at granular scales of the scattering polarization peak of the Sr I 4607 Å line at different limb distances, and to study the correlation with the continuum intensity.

Methods. Using the Zurich IMaging POLarimeter (ZIMPOL) system mounted at the GREGOR telescope and spectrograph in Tenerife, Spain, we carried out spectro-polarimetric measurements to obtain the four Stokes parameters in the Sr I line at different limb distances, from μ = 0.2 to μ = 0.8, on the solar disk.

Results. Spatial variations of the scattering polarization signal in the Sr I 4607 Å line, with a spatial resolution of about 0.66″, are clearly observed at every μ. The spatial scale of these variations is comparable to the granular size. A statistical analysis reveals that the linear scattering polarization amplitude in this Sr I spectral line is positively correlated with the intensity in the continuum, corresponding to the granules, at every μ.
Galaxy disc scaling relations: A tight linear galaxy–halo connection challenges abundance matching
Authors: Posti Lorenzo , Marasco Antonino , Fraternali Filippo , Famaey Benoit
Published: August 2019

In ΛCDM cosmology, to first order, galaxies form out of the cooling of baryons within the virial radius of their dark matter halo. The fractions of mass and angular momentum retained in the baryonic and stellar components of disc galaxies put strong constraints on our understanding of galaxy formation. In this work, we derive the fraction of angular momentum retained in the stellar component of spirals, fj, the global star formation efficiency fM, and the ratio of the asymptotic circular velocity (Vflat) to the virial velocity fV, and their scatter, by fitting simultaneously the observed stellar mass-velocity (Tully–Fisher), size–mass, and mass–angular momentum (Fall) relations. We compare the goodness of fit of three models: (i) where the logarithm of fj, fM, and fV vary linearly with the logarithm of the observable Vflat; (ii) where these values vary as a double power law; and (iii) where these values also vary as a double power law but with a prior imposed on fM such that it follows the expectations from widely used abundance matching models. We conclude that the scatter in these fractions is particularly small (∼0.07 dex) and that the linear model is by far statistically preferred to that with abundance matching priors. This indicates that the fundamental galaxy formation parameters are small-scatter single-slope monotonic functions of mass, instead of being complicated non-monotonic functions. This incidentally confirms that the most massive spiral galaxies should have turned nearly all the baryons associated with their haloes into stars. We call this the failed feedback problem.
HD 965: An extremely peculiar A star with an extremely long rotation period
Authors: Mathys G. , Romanyuk I. I. , Hubrig S. , Kudryavtsev D. O. , Schöller M. , Semenko E. A. , Yakunin I. A.
Published: August 2019

Context. One of the keys to understanding the origin of Ap stars and their significance in the general context of stellar astrophysics is by considering the most extreme properties displayed by some of them. For this reason, HD 965 is particularly interesting as it combines some of the most pronounced chemical peculiarities with one of the longest rotation periods known.

Aims. We characterise the variations of the magnetic field of the Ap star HD 965 and derive constraints about its structure.

Methods. We combined published measurements of the mean longitudinal field ⟨Bz⟩ of HD 965 with new determinations of this field moment from circular spectropolarimetry obtained at the 6-m telescope BTA of the Special Astrophysical Observatory of the Russian Academy of Sciences. For the mean magnetic field modulus ⟨B⟩, literature data were complemented by the analysis of ESO archive spectra.

Results. We present the first determination of the rotation period of HD 965, Prot = (16.5 ± 0.5) yr. The star HD 965 is only the third Ap star with a period longer than ten years for which magnetic field measurements have been obtained over more than a full cycle. The variation curve of ⟨Bz⟩ is well approximated by a cosine wave. Furthermore, ⟨B⟩ does not show any significant variation. The observed behaviour of these field moments is well represented by a simple model consisting of the superposition of collinear dipole, quadrupole, and octupole. The distribution of neodymium over the surface of HD 965 is highly non-uniform. The element appears concentrated around the magnetic poles, especially the negative one.

Conclusions. The shape of the longitudinal magnetic variation curve of HD 965 indicates that its magnetic field is essentially symmetric about an axis passing through the centre of the star. Overall, HD 965 appears similar to the bulk of the long-period Ap stars, as far as its magnetic field is concerned.
Endoscopic ultrasound-guided rendezvous in benign biliary or pancreatic disorders with a 22-gauge needle and a 0.018-inch guidewire
Authors: Martínez Belén , Martínez Juan , Casellas Juan Antonio , Aparicio José R.
Published: August 2019

Background and study aims The aim of this study was to assess the efficacy and safety of endoscopic ultrasound-guided rendezvous (EUS-RV) for benign biliary or pancreatic disorders with a 22-gauge needle and a 0.018-inch guidewire.

Patients and methods Patients who underwent EUS-RV after failed biliary or pancreatic cannulation for benign disorder were candidates for this study. For EUS-RV, a 22-gauge needle and a 0.018-inch guidewire were used. Inclusion criteria were unsuccessful biliary or pancreatic cannulation for therapeutic endoscopic retrograde cholangiopancreatography (ERCP) with benign biliary or pancreatic obstruction. Exclusion criteria included malignant biliary or pancreatic obstruction, inaccessible papilla due to surgically altered upper gastrointestinal anatomy or duodenal stricture, and previous sphincterotomy and/or biliary stent placement. The primary outcome was the technical success rate of biliary or pancreatic cannulation, and the secondary outcome was the rate of adverse events.

Results Thirty-one patients were evaluated. The overall technical success rate was 80.6 % (81.5 % in biliary and 75 % in pancreatic cases). Adverse events (AEs) were identified in 12.9 % of patients, including one with biliary peritonitis, one with abdominal pain and one with severe pancreatitis plus pneumomediastinum. Only one of the AEs (3.3 %) was directly related to the rendezvous procedure.

Conclusions EUS-RV may be a safe and feasible salvage method for unsuccessful cannulation for benign disorders. Use of a 22-gauge needle with a 0.018-inch guidewire may be the first option for benign pathology.
Outcome of endoscopic resection of colonic polyps larger than 10 mm in patients with inflammatory bowel disease
Authors: Yadav Siddhant , Loftus Edward V. , Harmsen W. Scott , Wong Kee Song Louis M. , Coelho-Prabhu Nayantara
Published: August 2019

Background and study aims There are limited published data on endoscopic removal of colorectal polyps by endoscopic mucosal resection (EMR) and endoscopic mucosal dissection (ESD) in patients with inflammatory bowel disease (IBD).

Patients and methods We performed a retrospective review of patients with colonic IBD and colonic polyps >10mm who underwent EMR and/or ESD at our institution between January 1, 2012 and June 31, 2016.

Results Ninety-seven patients with pathology-confirmed IBD (median disease duration 16 years) were included. Mild or moderate active colitis (in background biopsies) was seen in 85 %. Of the total 124 polyps, location was ascending colon in 44 %, transverse in 15 % and sigmoid in 18.5 %; of the total, 55 % were < 20 mm and 45 % were ≥20mm in maximal diameter. Using the Paris classification, 56 % of polyps were polypoid sessile (Is) polyps, while 38 % were non-polypoid (IIa, IIb, IIc). EMR was used in 118 polyps, three required ESD, and three by combined EMR-ESD. Seventy-two percent were resected en-bloc; 28 % underwent piecemeal resection. Histology included low-grade dysplasia in 75, serrated adenoma in 31, and tubular adenoma in 14 polyps. Chromoendoscopy was used in 33 (26.6 %). Adverse events occurred in three patients. Colectomy was performed in 11 patients within 12 months. Recurrence was seen in 20 polyps, 11 of which were successfully resected en-bloc using EMR. Polyps ≥ 20 mm and polyps treated with APC were found to have a statistically significantly higher risk of recurrence.

Conclusion This study demonstrates the efficacy and safety of endoscopic resection of large polyps in patients with IBD, making them effective alternatives to colectomy.
Utilizing fourth-generation endocytoscopy and the ‘enlarged nuclear sign’ for in vivo diagnosis of early gastric cancer
Authors: Abad Mary Raina Angeli , Inoue Haruhiro , Ikeda Haruo , Manolakis Anastassios , Rodriguez de Santiago Enrique , Sharma Ashish , Fujiyoshi Yusuke , Fukuda Hisashi , Sumi Kazuya , Onimaru Manabu , Shimamura Yuto
Published: August 2019

Background and study aims Fourth-generation endocytoscopy is an ultra-high magnification endoscopic technique designed to provide excellent quality in vivo histologic assessment of gastrointestinal lesions. This study aims to evaluate the diagnostic accuracy of endocytoscopy in early gastric cancer diagnosis.

Patients and methods A single-center, retrospective analysis of prospectively collected data from all gastric endocytoscopic examinations was conducted. Two expert endoscopists, blinded to white-light and narrow-band imaging findings as well as histopathologic diagnosis, independently reviewed and diagnosed all endocytoscopic images. A newly recognized “enlarged nuclear sign” was detected, and its implication in early gastric cancer diagnosis was evaluated. The diagnostic performance of fourth-generation endocytoscopy was assessed while using the gold standard histopathology as a reference.

Results Forty-three patients (mean age±SD, 72.6 ± 12.1 years; 31 males) were enrolled. Based on histopathology, 23 had well-differentiated adenocarcinomas, four adenomas, and 16 non-neoplastic lesions. The sensitivity, specificity, and accuracy of fourth-generation endocytoscopy for gastric cancer diagnosis were 87.0 % (95 % CI: 67.9 – 95.5), 80.0 % (95 % CI: 58.4 – 91.9), and 83.7 % (95 % CI: 70.0 – 91.9) by endoscopist A; and 91.3 % (95 % CI: 73.2 – 97.6), 75.0 % (95 % CI: 53.1 – 88.8), and 83.7 % (95 % CI: 70.0 – 91.9) by endoscopist B. The inter-observer agreement, Kappa statistic = 0.71 (95 % CI: 0.50 – 0.93), was good. The sensitivity, specificity, and accuracy of the enlarged nuclear sign for early gastric cancer diagnosis were 87.0 % (95 % CI: 67.9 – 95.5), 95.0 % (95 % CI: 76.4 – 99.1), and 90.7 % (95 % CI: 78.4 – 96.3) by endoscopist A; and 82.6 % (95 % CI: 62.9 – 93.0), 85.0 % (95 % CI: 64.0 – 94.8), and 83.7 % (95 % CI: 70.0 – 91.9) by endoscopist B. The inter-observer agreement, Kappa statistic = 0.68 (95 % CI: 0.51 – 0.89) was good.

Conclusion: Fourth-generation endocytoscopy appears to aid in the diagnosis of early gastric cancer, particularly well-differentiated adenocarcinomas, due to its good diagnostic accuracy and identification of the “enlarged nuclear sign,” and deserves further evaluation in future studies.
Gute Praxis Datenlinkage (GPD)
Authors: March Stefanie , Andrich Silke , Drepper Johannes , Horenkamp-Sonntag Dirk , Icks Andrea , Ihle Peter , Kieschke Joachim , Kollhorst Bianca , Maier Birga , Meyer Ingo , Müller Gabriele , Ohlmeier Christoph , Peschke Dirk , Richter Adrian , Rosenbusch Marie-Luise , Scholten Nadine , Schulz Mandy , Stallmann Christoph , Swart Enno , Wobbe-Ribinski Stefanie , Wolter Antke , Zeidler Jan , Hoffmann Falk
Published: August 2019

Das personenbezogene Verknüpfen verschiedener Datenquellen (Datenlinkage) für Forschungszwecke findet in den letzten Jahren in Deutschland zunehmend Anwendung. Jedoch fehlen hierfür konsentierte methodische Standards. Ziel dieses Beitrages ist es, solche Standards für Forschungsvorhaben zu definieren. Eine weitere Intention ist es, dem Lesenden eine Checkliste zur Bewertung geplanter Forschungsvorhaben und Artikel bereitzustellen. Zu diesem Zweck hat eine aus Mitgliedern verschiedener Fachgesellschaften zusammengesetzte Expertengruppe seit 2016 insgesamt 7 Leitlinien mit 27 konkreten Empfehlungen erstellt. Die Gute Praxis Datenlinkage beinhaltet die folgenden Leitlinien: (1) Forschungsziele, Fragestellung, Datenquellen und Ressourcen, (2) Dateninfrastruktur und Datenfluss, (3) Datenschutz, (4) Ethik, (5) Schlüsselvariablen und Linkageverfahren, (6) Datenprüfung/Qualitätssicherung sowie (7) Langfristige Datennutzung für noch festzulegende Fragestellungen. Jede Leitlinie wird ausführlich diskutiert. Zukünftige Aktualisierungen werden wissenschaftliche und datenschutzrechtliche Entwicklungen berücksichtigen.
Instant messenger smartphone application for endosonographer/cytopathologist real-time interaction at a distance in EUS-FNA for solid pancreatic lesions
Authors: Machado Rodrigo S. , Richa Rafaela , Callegari Fabiano , Souza Giovana B. , Tolentino Luciano L. , Nakao Frank S. , Ferrari Angelo , Libera Ermelino
Published: August 2019

Background and study aims Telecytopathology (TCP) may allow proper and timely evaluation of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) specimens. The aim of this study was to evaluate the feasibility of TC through a multiplatform instant messenger smartphone application to evaluate specimens of EUS-FNA of pancreatic solid lesions.

Patients and methods Twenty-three patients (14 male/9 female; median age: 56 yr.; age range: 33 – 86) with a solid pancreatic lesion were included. Exclusion criteria were as follows: age < 18 yr and predominantly cystic lesions. During each EUS-FNA, after each pass, the aspirated material was spread over a glass slide and was stained by the endoscopist. The glass slide was then reviewed on a microscope with a smartphone fitted in, and the most representative fields were captured and sent to the cytopathologist using WhatsApp Messenger.

Results In initial evaluation using TCP rapid on-site evaluation (ROSE), adequate cellularity of the glass slide was detected in 16 of 23 patients (69.6 %). An initial diagnosis of malignancy (positive or suspicious) was possible in 14 of 23 patients (60.8 %).

Conclusion The current study demonstrated the feasibility of a low-cost, Internet-based, telecytopathology system using WhatsApp Messenger to provide ROSE of EUS-FNA slides in patients with solid pancreatic lesions.
Reviewing Complex Static-Dynamic Concepts of Spine Stability: Does the Spine Care Only to Be Stiff to Be Stable?
Authors: Mahato Niladri Kumar
Published: August 2019

Background Changes in the load-displacement relationship in spine segments suggesting alterations in biomechanical stiffness may not yield significant clinical information. Changes in Spine stiffness may arise secondary to neuro-muscular adjustments in the para-spinal muscles and may not be associated with physical anatomical laxity or motion restrictions at segmental articulations. Segmental stiffness may vary dynamically at different zones within the range-of-motion, suggesting a non-linear load-displacement relationship during motion. There is no linear, mechanistic relationship between spine pain and biomechanical markers of spine instability.

Objective To review diagnostic assessment approaches of spine instability based on palpatory techniques, end-of-range radiography and imaging in light of our current understanding of biomechanical spine stability.

Method The Medline and PubMed databases were screened for primary medical and engineering research articles and reviews on spine stability. Information related to bio-mechanical concepts and clinical decision-making were extracted and synthesized. Spine stability was described in two classical forms, the structural (anatomical) and the functional (physiological), the implications of static and dynamic instability was described in terms of biomechanical and mathematical models used to understand etiology of non-specific back pain.

Results Evidence supports the view that dynamic adaptations in the load-displacement relationship of the spine may be resistive or assistive, depending on task-specific movements. Diagnosis of instability is based on structural and functional integrity of the segments in a static or dynamic context.

Conclusion Development of specific criteria to define clinical spine stability, compatible with system-based biomechanical concept of spine stiffness, is an ongoing topic in clinical and basic science research.
Estimation of Adult Human Height from the Bigonial Width and Mandibular Arch
Authors: Aragão José Aderval , Santana Guilherme Machado de , Sacramento Erick Mendonça do , Marcelo Israel Santos , Aragão Iapunira Catarina Sant'Anna , Sant'Anna Aragão Felipe Matheus , Reis Francisco Prado
Published: August 2019

Introduction An individual's sex, age and height are of great importance in legal medicine, especially with regard to identifying corpses. Height estimates are based on the proportionality relationship that exists between an individual's height and his various body parts.

Objective To analyze the relationship between mandible measurements (length of the mandibular arch and bigonial width) and height.

Materials and methods This study was conducted on the population of the Mussuca quilombo settlement, which is in the municipality of Laranjeiras, state of Sergipe, Brazil. The sample was composed of 300 individuals: 150 women and 150 men aged between 18 and 85 years old. The statistical analysis was done using the Statistical Package for the Social Scienes SPSS®, version 19.0, for Windows (SPSS Inc., Chicago, EUA) and Excel 2010 (Microsoft Corp., Redmond, WA, USA).

Results The correlation coefficients were found to be low, with weak correlations between the measurements of the mandibula and height. Analysis on these values shows a very small positive correlation between height and the length of the mandibular arch among males (r = 0.177; p < 0.05) and among females (r = 0.271; p = 0.001); and between height and bigonial width among females (r = 0.169; p < 0,05).

Conclusion Height may be estimated less exactly in cases in which only cephalofacial dimensions are available for legal medical examination.
Effects of Neuroendocrine Centers on Germ and Germline Cells in Dendrobaena atheca Cernosvitov (Annelida: Lumbricidae)
Authors: Gorgees Najem Shlemoon , Kiret Ziyad Tahseen
Published: August 2019

The aim of the present comprehensive experimental study was to reveal the effects of the removal and the regeneration of the main neuroendocrine centers in the oogonia, oocytes and trophocytes in Dendrobaena atheca. Various types of serial sections of ovaries and cephalic regions were obtained. Four histological staining techniques were employed. In controlled preparations, the neurosecretory activities of A-cells and C-cells showed correlation with cellular activities of oogonia, oocytes and trophocytes. In experimental preparations, removal of A-cells caused abnormalities in oocytes and trophocytes. The regeneration of A-cells restored vitellogenesis and repaired abnormalities. In both preparations, C-cells remained aldehyde-fuchsin (AF)-positive. B-cells and U-cells remained AF-negative. The oogonia showed continuous mitotic divisions. Regenerated A-cells appeared in week 3, increased in number, but could not stop the abnormalities, as hormones were not transported due to the lack or scarcity of blood capillaries. Therefore, abnormalities increased extremely. Then, they stopped, decreased, and were repaired due to hormonal transport via fully reconstructed blood capillary plexuses. The main conclusions are: (1) oocytes and trophocytes are controlled by A-cells, since they exhibited prominent changes during the removal and regeneration of A-cells; (2) oogonia are controlled by C-cells, as they showed correlation of activities with C-cells and were not affected by the removal and regeneration of A-cells; (3) B-cells and U-cells remained inactive; hence, they have no role in oogonia divisions and vitellogenesis; and (4) delayed hormonal effects of regenerated A-cells were due to the lack or scarcity of blood capillaries. Therefore, fully reconstructed blood capillary beds in the A-cells area are indispensable for hormonal diffusion, transport and effectivity.
Primary Stability in Cementless Rotating Platform Total Knee Arthroplasty
Authors: Small Scott R. , Rogge Renee D. , Reyes Eric M. , Seale Ryan B. , Elliott Jeffrey B. , Malinzak Robert A.
Published: August 2019

Highly porous ingrowth surfaces have been introduced into tibial tray fixation to improve long-term survivorship in cementless total knee arthroplasty. This study was designed to evaluate the effect of porous ingrowth surface on primary stability in the implanted cementless tibial component. Three tibial tray designs possessing sintered bead or roughened porous coating ingrowth surfaces were implanted into a foam tibia model with primary stability assessed via digital image correlation during stair descent and condylar liftoff loading. Follow-up testing was conducted by implanting matched-pair cadaveric tibias with otherwise identical trays with two iterations of ingrowth surface design. Trays were loaded and micromotion evaluated in a condylar liftoff model. The sintered bead tibial tray exhibited slightly lower micromotion than the roughened porous coating in stair descent loading. However, no significant difference in primary stability was observed in condylar liftoff loading in either foam or cadaveric specimens. Cementless tibial trays featuring two different iterations of porous ingrowth surfaces demonstrated both good stability in cadaveric specimens with less than 80 microns of micromotion and 1 mm of subsidence under cyclic loading. While improved ingrowth surfaces may lead to improved biological fixation and long-term osteointegration, this study was unable to identify a difference in primary stability associated with subsequent ingrown surface design iteration.
Effect of h-BN and Fe3O4 nanoparticles on streamer propagation and dissipation in vegetable oil based nanofluids
Authors: Yao Wei , Wang Wei , Sun Peng , Mehmood Muhammad Ali , Huang Zhengyong
Published: August 2019

Nanoparticles enhance the positive and negative lightning breakdown voltages of vegetable insulating oils due to a reduced streamer velocity. Pre-breakdown streamers in vegetable oil based h-BN and Fe3O4 nanofluids were observed using the shadowgraph method under a lightning impulse voltage. The propagation of streamers until their stopping length is analyzed using shadowgraph images for the different nanofluids. The results suggest that these nanofluids present a higher breakdown voltage per unit length compared with pure oil. Secondary reverse streamers are observed to appear at the dissipation stage of the streamer. In particular, the secondary reverse streamer of the nanofluids appeared earlier and seemed to be shorter than that of pure oil under positive impulse voltages. The underlying mechanism was analyzed using space charge theory.
Simulations corroborate telegraph model predictions for the extension distributions of nanochannel confined DNA
Authors: Bhandari Aditya Bikram , Dorfman Kevin D.
Published: August 2019

Hairpins in the conformation of DNA confined in nanochannels close to their persistence length cause the distribution of their fractional extensions to be heavily left skewed. A recent theory rationalizes these skewed distributions using a correlated telegraph process, which can be solved exactly in the asymptotic limit of small but frequent hairpin formation. Pruned-enriched Rosenbluth method simulations of the fractional extension distribution for a channel-confined wormlike chain confirm the predictions of the telegraph model. Remarkably, the asymptotic result of the telegraph model remains robust well outside the asymptotic limit. As a result, the approximations in the theory required to map it to the polymer model and solve it in the asymptotic limit are not the source of discrepancies between the predictions of the telegraph model and experimental distributions of the extensions of DNA during genome mapping. The agreement between theory and simulations motivates future work to determine the source of the remaining discrepancies between the predictions of the telegraph model and experimental distributions of the extensions of DNA in nanochannels used for genome mapping.
Family farms and the markets: examining the level of market-oriented production 15 years after the Zimbabwe Fast Track Land Reform programme
Authors: Muchetu Rangarirai Gavin
Published: August 2019

Small family farmers aim to secure food through own production, and the surplus is only sold to finance productive and reproductive investments. The Fast Track Land Reform programme (FTLRP) caused a dramatic increase in the number of family farms, with approximately 180,000 families being resettled on 70% of agricultural land previously held by about 4500 commercial white farmers. This increased demand for agricultural capital goods, thus putting pressure on the under-resourced government of Zimbabwe, which had to provide inputs considering the FTLRP and capital outflows induced by the economic meltdown. The study tracks and maps out the position of family farmers in Zimbabwe with respect to the agricultural inputs and outputs markets over 15 years of land reform implementation. Specifically, the study utilises the SMAIAS 2013–14 Household Survey to calculate commercialisation indices for major agricultural crops in Zimbabwe. Commercialisation involves the creation of mechanisms that encourage farmers’ active participation and integration in the commodity markets. The survey results show that participation is found to be highly differentiated, with small-scale producers participating the least. More farmers were more active in the inputs markets than they were in the outputs markets, thus implying a perennial reduction of farmers’ incomes and productive asset investment capacity. Additionally, the study provides structural transformative policy alternatives for improving production and rural household income to reduce poverty.
Tunable magnetic skyrmions in spintronic nanostructures for cellular-level magnetic neurostimulation
Authors: Saha Renata , Wu Kai , Su Diqing , Wang Jian-Ping
Published: August 2019

Electrical probes and arrays are currently ruling the market in treating neurodegenerative, sensory and cardiovascular diseases. Despite the accomplishments, their performance is limited by high power of operation, tissue inflammation, biofouling, inefficient control of electric fields and significant incompatibility for patients who are qualified to take magnetic resonance imaging tests only. Another alternative is magnetic stimulation. In this paper, we have proposed an implantable, highly tunable skyrmion-based neurostimulator (SkyNS). The displacement of magnetic skyrmions in a metallic bilayer generates a time varying magnetic field which induces an electric field gradient large enough to trigger neuron stimulation. SkyNS operates with a current of 2.71 µA and consumes a power of 1.434 nW. The effects of Dzyaloshinskii–Moriya interaction, perpendicular magnetic anisotropy and device dimensions on stable skyrmion nucleation and smooth skyrmion dynamics in a heavy metal/ferromagnetic metal bilayer have been extensively studied by micromagnetic simulation on mumax3. This work provides a proof-of-concept to exploit the material tunability of skyrmion-based spintronic nanodevices as cellular-level, ultra-low power, implantable magnetic neurostimulators.
Interaction of O–Y and O–Y–Ti clusters embedded in bcc Fe with He, vacancies and self-interstitial atoms
Authors: Vallinayagam Muthu , Posselt Matthias , Faßbender Jürgen
Published: August 2019

Calculations based on density functional theory are performed to investigate the interaction of O–Y and O–Y–Ti clusters in bcc Fe with He atoms, vacancies (v) and self-interstitial atoms (SIA). The four different cluster structures studied in our previous work (J. Phys.: Condens. Matter
31 095701) are considered. He, v and SIA are inserted on different positions inside and in the environment of the clusters, the total energy of the corresponding supercell is minimized and the binding and incorporation energy of the three kinds of defects is determined. He in the center of a cage-like (CL) cluster is more stable than on interfacial vacant sites (IVS). In CL O–Y clusters He on an IVS is more stable than in the cluster structure with oxygen in the center, whereas there is no significant difference between the two kinds for clusters with Ti. Up to a distance of 1.5 times the iron lattice constant from the cluster center He is not stable on most of the octahedral and tetrahedral interstitial sites in the Fe matrix near the interface. Instead He is shifted towards positions closer to the cluster. Relaxation occurs to known IVS as well as to previously unknown interfacial interstitial sites. Moreover, two or three He atoms are placed on sites found to be stable after adding a single He. The corresponding binding and incorporation energies obtained after relaxation are nearly equal to the sum of the values for the interaction with a single He atom. However, placing He dimers or trimers in the environment of a vacancy may also lead to relatively low values of the incorporation energy. Also, barriers for jumps of He atoms between interfacial sites and the center of CL clusters are determined. In the CL O–Y cluster the barriers are lower than in the CL O–Y–Ti cluster, i.e. trapping and release of He is easier in the former than in the latter. v and SIA interaction with the clusters is also attractive. The binding energy of v strongly depends on the site where v is inserted while in all studied cases the SIA is annihilated at the cluster-iron interface. Present results clearly demonstrate that the oxide-based nanoclusters are strong traps for irradiation induced defects which is in agreement with experimental findings.
Is there anything wrong? The inconsistency of argument with the table of truth
Authors: Darmadi
Published: August 2019

The main character of the materials of mathematics is consistent. A problem emerged and became the focus of the research is obtained an inconsistency in mathematics. Research methods used are qualitative research methods. Data were taken with the use of interview-based tests and observation. The research results showed that: 1) there is an inconsistency in argumentation learning logic and mathematical set; 2) Inconsistency argument inspection results occur because of difference in taking for example; and 3) Lecture need to pay attention to the machining process of the students. As a result, in the study of cognitive conflicts can be happen in students and lecturers.
Students’ misconceptions on the algebraic prerequisites concept: causative factors and alternative solutions
Authors: Permata Dea , Wijayanti P , Masriyah
Published: August 2019

Mastery of the concept of number operations is the main prerequisite for understanding the algebraic concepts. The misconception of integer operations is still widely found in students. This research aimed to describe students’ misconceptions on the algebraic prerequisites concept, namely the operation of integers, causative factors and alternative solutions. This research was qualitative descriptive research using diagnostic test methods and interview. Three students who did the most and varied misconceptions were chosen to be the subject of this research. The results showed the misconceptions experienced by the subject occurred in the integer addition, integer subtraction, integer division and multiplication with zero numbers. The factors that cause misconception were wrong intuition and incorrect or incomplete reasoning and alternative solutions were re-explain and cognitive conflict. For further research, other researchers can conduct research on students’ misconceptions on the algebraic prerequisites concept besides number operations.
Profile of mathematical reasoning ability of female students based on self-efficacy
Authors: Karunika A M , Kusmayadi T A , Fitrana L
Published: August 2019

Reasoning was an important aspect for solving the linear programming problems. Furthermore, the male students performed the spatial ability tests better than the female students. The female students solved the problem by creating a solution plan and looked at the keywords in the problem. This research used qualitative research. The subjects of this research were the of 11th grade of senior high school students taken by using purposive sampling. The techniques of collecting data used in this research were a linear program problem test and self-efficacy questionnaire. The research result revealed that the female students who had high self-efficacy in mathematical reasoning ability explained the use of models, facts, properties, relations to use pattern and relations to analyze the mathematical situation; provided an explanation about the models, the pictures, the facts, the natures, the relationships or the existing patterns; and did mathematical manipulations. In addition, the female students who had medium and low self-efficacy in mathematical reasoning ability were able to draw the analogy, the generalization and could use of pattern and the relation to analyze the mathematical situations and provided an explanation about the models, the pictures, the facts, the natures, the relationships or the existing patterns.
Teacher’s strategies to promote student’s mathematical competencies in algebra: a case study
Authors: Masduki Masduki , Suwarsono Stephanus , Budiarto M T
Published: August 2019

Mathematical competence is knowledge, skill, and ability to use mathematics for solving problems of both mathematical and non-mathematical context. The PISA and TIMSS reports indicate the low quality of mathematical competence of students in Indonesia. One of the most influential factors in the quality of learning is teachers. The paper aims to describe the teacher’s strategies to promote students’ mathematical competence in algebra. The case study method was used to investigate the strategies used by mathematics teacher in conducting teaching activity on 7th grade. The data was collected through observation and interview. The observation was conducted three times. Field notes, observation guideline, and video recorder were used to collect the data of teacher’s strategies in the classroom. Interview was conducted at the end of the observation activity. A semi-structured interview was done to collect further information regarding the teacher’s strategies. The results show that the teacher used various strategies to promote students mathematical competence in understanding the mathematical concept and using reasoning. However, a lack of strategies to promote students in using the pattern as a conjecture to solve the problem and communicating the idea is identified.
Improving reasoning ability through contextual teaching and learning in differential equations
Authors: Pramujiyanti Khotimah Rita , Masduki
Published: August 2019

One of important aspects in mathematics learning is reasoning. This research aims to improve students’ reasoning ability through contextual teaching and learning in differential equations. This is a research and development based on lesson study. The subjects are 34 students of the fifth semester of the Department of Mathematics Education, Universitas Muhammadiyah Surakarta. The data were collected through observation, field notes, test and documentation. The technique of data analysis was a flow-method that consisted of data reduction, data display and verification. The result showed that there were the increase in the average values of the indicators of reasoning ability as follows: 1) analyzing the problems of 3.5; 3.59; and 3.88, 2) organizing the settlement of 2.18; 3.31; and 3.41, 3) interpreting the results of 2.18; 3.0; and 3.32, and 4) explaining the problems of 1.44; 2.01; and 3.29. It can be concluded that the implementation of contextual teaching and learning is able to improve the student reasoning ability in differential equations.
Creative thinking process of female elementary school student with visual learning style in mathematical problem solving
Authors: Ishabu La Suha , Ketut Budayasa I. , Eko Siswono T.Y.
Published: August 2019

In solving mathematical problems, the creative thinking process is basically assessed based on two indicators: creative processes and products. The creative process is the stage of creative thinking that includes generating ideas, planning problem solving, and producing problem solving. The process generates creative products should meet the aspects of fluency, flexibility, and novelty. The present study aims at describing the creative thinking process of elementary school students in solving mathematical problems. It involved female student who practiced visual learning style as the subject with the consideration the subject could generate a flexible product, but not an extraordinary product that meets the aspects of fluency and novelty. Data was collected through test and in-depth interview. The validity was done with data triangulation technique. The collected data were analyzed with transcription, categorization, reduction, interpretation and conclusion. The findings indicate that the creative thinking process of elementary school students in mathematical problem solving is realized through generating ideas (reading and examining images in the question) to identify information that is already known, to employ different approaches for planning problem solving, and to produce creative products that meet the aspect of flexibility. Nevertheless, the products have not fulfilled the aspects of fluency and novelty.
Longitudinal data exploration of upper respiratory tract infection disease in Bandung city
Authors: Tantular B , Jaya I G N M , Andriyana Y
Published: August 2019

Longitudinal data have a complex structure. Unlike cross-sectional data, there are more associated features with longitudinal data. Associated features to longitudinal data including the heterogeneity between subjects, the serial correlation and the characteristics of changes over time. Therefore exploring longitudinal data is more complicated than that of cross-sectional data. Various methods were developed by many researchers to explore longitudinal data. In general, there are at least three things that could be described from longitudinal data: mean structure, variance structure, and correlation structure. Visual methods and subject-specific profile were studied for such datasets to detect these structures. Methods were applied to data sets from upper respiratory tract infection data in Bandung City. From the result, we can describe the growth patterns at both group and individual level and then selecting suitable statistical models which contain within and between groups variations.
Comparative neutron-shielding properties of metal oxide/HDPE composites using a Monte Carlo Code of PHITS
Authors: Poltabtim W , Toyen D , Saenboonruang K
Published: August 2019

Development of efficient neutron-shielding materials has become one of the most important issues in radiation safety. In order to estimate shielding performances of the materials of interest, simulations of neutron-shielding characteristics using well-proved methods are necessary. In this work, a Monte Carlo code of Particle and Heavy Ion Transport code System (PHITS) was used to simulate neutron-shielding properties of HDPE composites that were added with either B2O3, Sm2O3, Gd2O3, or CdO as a filler at various contents. The energy of the incoming neutrons was fixed at 0.025 eV with the beam direction pointing at the right angle to the material’s surface. The results showed that Gd2O3/HDPE composites had the lowest neutron transmission ratio compared with other fillers at the same contents, implying the highest neutron-shielding ability. Furthermore, the simulations also showed that the values of neutron transmission ratios of all fillers decreased with increasing filler’s contents. Other information such as half-value-layer (HVL) and tenth-value-layer (TVL) were also simulated and reported in this work. We encouraged further investigation of this work by comparing the simulated results with the actual experiment in order to validate the accuracy of the simulation.
Manufacturing process and properties of lead-free natural rubber sponge for use in X-ray and gamma ray shielding applications
Authors: Lim-aroon P , Wimolmala E , Sombatsompop N , Saenboonruang K
Published: August 2019

In this work, light-weighted, flexible, and lead-free X-ray/gamma-ray shielding natural rubber (NR) sponges were developed with the help of a blowing agent, namely Oxybis (benzene sulfonyl) hydrazide (OBSH) (its contents varied from 0, 8 to 16 parts per hundred parts of rubber; phr), and an X-ray/gamma protective filler, namely bismuth oxide (Bi2O3) (its content varied from 0, 100, 300, to 500 phr) in natural rubber (NR) composites. The results suggested that the densities and overall mechanical properties decreased with increasing contents of OBSH, while the increases in B2O3 resulted in the increases in tensile strength and hardness (Shore A), however, initially increases tensile strength and elongation at break but later decreases at 300 and 500 phr. In terms of radiation shielding properties, it was found that the ability to attenuate X-rays and gamma rays improved with increasing Bi2O3 contents. Hence, the overall properties investigated in this work suggested that the developed NR sponges could be used to attenuate X-rays and gamma rays efficiently with additional properties of being light-weighted and highly flexible, which are crucial for safety of radiation-related personnel and users.
Electrical interaction between nanoparticle and surface of material
Authors: Summueang C. , Boonchui S.
Published: August 2019

We identify the interaction between nanoparticle and surface of material in the presence of an electric field. For theoretical calculation, we use the dyadic green function that includes with the method of image dipoles to analyze electrical interaction. We find that the electric field and the interaction potential which depend on the dielectric constant and surface roughness of material. Our numerical results demonstrate the electric field and the interaction potential which corresponds to the Van der Waals interaction and can be used to determine charges distribution on nanoparticle and surface of material.
Efficacy of cold atmospheric pressure plasma jet against Enterococcus faecalis in apical canal of human single-rooted teeth: a preliminary study
Authors: Saleewong K , Wanachantararak P , Louwakul P
Published: August 2019

Many factors that may affect the success of root canal treatment are complexity of root canal system, especially in the apical part, and the virulence of bacteria such as biofilm formation. A cold atmospheric pressure plasma jet is a novel method for sterilization and applied for root canal disinfection. The purpose of this study was to investigate the effect of the cold atmospheric pressure plasma jet on Enterococcus faecalis (E. faecalis) biofilms infected in the apical root canals. Methods: Fifty-four single rooted-teeth were infected with E. faecalis for seven days and allocated into five groups. Group I performed as positive control. Group II-V were served as experimental groups: NaOCl, plasma, NaOCl + plasma and gas only, respectively. The disinfection was evaluated by colony count (per milligram) at the depths of 0.05 and 0.10 mm of root dentin. The remaining bacteria was also counted from the grounded root dentin. Data was analysed by one-way ANOVA and post hoc test, with a level of significance set at P<.05. Results: The NaOCl, plasma and NaOCl + plasma groups significantly reduced the E. faecalis, but no significant difference was found among these groups (P>0.5). The NaOCl + plasma group significantly reduced E. faecalis in the deeper dentin level compared to the other groups. Conclusion: The cold atmospheric pressure plasma jet had antimicrobial activity against E. faecalis biofilm as well as the use of NaOCl. The combined treatment yielded the most promising result and may be beneficial in root canal disinfection.