bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epigenetic patterns associated with an ascidian invasion: a comparison of closely related clades in their native and introduced ranges
Authors: Hawes Nicola A. , Amadoru Achira , Tremblay Louis A. , Pochon Xavier , Dunphy Brendon , Fidler Andrew E. , Smith Kirsty F. 
Published: October 2019

AbstractEnvironmentally induced epigenetic modifications have been proposed as one mechanism underlying rapid adaptive evolution of invasive species.Didemnum vexillumis an invasive colonial ascidian that has established in many coastal waters worldwide. Phylogenetic analyses have revealed thatD.vexillumpopulations consist of two distinct clades; clade B appears to be restricted to the native range (Japan), whereas clade A is found in many regions throughout the world, including New Zealand. The spread ofD.vexillumclade A suggests that it might be intrinsically more invasive than clade B, despite low levels of genetic diversity compared to populations from the native region. This study investigated whetherD.vexillumclade A exhibits epigenetic signatures (specifically differences in DNA methylation) associated with invasiveness. Global DNA methylation patterns were significantly different between introduced clade A colonies, and both clades A and B in the native range. Introduced colonies also showed a significant reduction in DNA methylation levels, which could be a mechanism for increasing phenotypic plasticity. High levels of DNA methylation diversity were maintained in the introduced population, despite reduced levels of genetic diversity, which may allow invasive populations to respond quickly to changes in new environments. Epigenetic changes induced during the invasion process could provide a means for rapid adaptation despite low levels of genetic variation in introduced populations.
Centrosomal and ciliary targeting of CCDC66 requires cooperative action of centriolar satellites, microtubules and molecular motors
Authors: Conkar Deniz , Bayraktar Halil , Firat-Karalar Elif Nur 
Published: October 2019

AbstractMammalian centrosomes and cilia play key roles in many cellular processes and their deregulation is linked to cancer and ciliopathies. Spatiotemporal regulation of their biogenesis and function in response to physiological stimuli requires timely protein targeting. This can occur by different pathways, including microtubule-dependent active transport and via centriolar satellites, which are key regulators of cilia assembly and signaling. How satellites mediate their functions and their relationship with other targeting pathways is currently unclear. To address this, we studied retinal degeneration gene product CCDC66, which localizes to centrosomes, cilia, satellites and microtubules and functions in ciliogenesis. FRAP experiments showed that its centrosomal pool was dynamic and the ciliary pool associated with the ciliary axoneme and was stable. Centrosomal CCDC66 abundance and dynamics required microtubule-dependent active transport and tethering, and was inhibited by sequestration at satellites. Systematic quantitation of satellite dynamics identified only a small fraction to display microtubule-based bimodal motility, consistent with trafficking function. Majority displayed diffusive motility with unimodal persistence, supporting sequestration function. Together, our findings reveal new mechanisms of communication between membrane-less compartments.
Novel Unexpected Reconstructions of (100) and (111) Surfaces of NaCl: Theoretical Prediction
Authors: Kvashnin Alexander G. , Kvashnin Dmitry G. , Oganov Artem R. 
Published: October 2019

AbstractWe have predicted stable reconstructions of the (100) and (111) surfaces of NaCl using the global optimization algorithm USPEX. Several new reconstructions, together with the previously reported ones, are found. For the cleaved bare (100) surface, pure Na and pure Cl are the only stable surface phases. Our study of the (111) surface shows that a newly predicted Na3Cl-(1 × 1) reconstruction is thermodynamically stable in a wide range of chlorine chemical potentials. It has a sawtooth-like profile where each facet reproduces the (100) surface of rock-salt NaCl, hinting on the preferred growth of the (100) surface. We used Bader charge analysis to explain the preferable formation of this sawtooth-like Na3Cl-(1 × 1) reconstruction of the (111) surface of NaCl. We find that at a very high chemical potential of Na, the polar (and normally absent) (111) surface becomes part of the equilibrium crystal morphology. At both very high and very low chemical potentials of Cl, we predict a large decrease of surface energy and fracture toughness (the Rehbinder effect).
Type I toxin-dependent generation of superoxide affects the persister life cycle of Escherichia coli
Authors: Edelmann Daniel , Berghoff Bork A. 
Published: October 2019

AbstractInduction of growth stasis by bacterial toxins from chromosomal toxin-antitoxin systems is suspected to favor formation of multidrug-tolerant cells, named persisters. Recurrent infections are often attributed to resuscitation and regrowth of persisters upon termination of antibiotic therapy. Several lines of evidence point to oxidative stress as a crucial factor during the persister life cycle. Here, we demonstrate that the membrane-depolarizing type I toxins TisB, DinQ, and HokB have the potential to provoke reactive oxygen species formation in Escherichia coli. More detailed work with TisB revealed that mainly superoxide is formed, leading to activation of the SoxRS regulon. Deletion of the genes encoding the cytoplasmic superoxide dismutases SodA and SodB caused both a decline in TisB-dependent persisters and a delay in persister recovery upon termination of antibiotic treatment. We hypothesize that expression of depolarizing toxins during the persister formation process inflicts an oxidative challenge. The ability to counteract oxidative stress might determine whether cells will survive and how much time they need to recover from dormancy.
Sexual dichromatism and color diversity in the spiny lava lizard Tropidurus spinulosus using lizard visual modelling
Authors: Rossi N. , Benitez-Vieyra S. , Cocucci A. , Chiaraviglio M. , Cardozo G. 
Published: October 2019

AbstractColors are important vehicles for social signals in many taxa. In Squamata, previous studies have linked color characteristics and chromatic diversity to sexual selection and, particularly, species showing male-biased body size dimorphism also showed male-biased dichromatism and color diversity. Sexual dichromatism may occur in body regions used for conspecific communication and it may be expressed at wavelengths, such as ultraviolet, easily perceivable by conspecifics. We tested this prediction in a social lizard model,Tropidurus spinulosus, using spectrophotometry and visual modelling which enable colors to be interpreted as the individuals of the same taxon see them. Our results indicate that sexual dichromatism occurs in the ventral regions and the flanks, which are the body regions involved in sexual displays. Males show greater color diversity, having larger color volumes and more contrasting colors. These findings reinforce the idea that sexual selection towards males is coupled with the evolution of male-biased, diverse, coloration which could act as a signal in social reproductive contexts.
Optical properties of folic acid in phosphate buffer solutions: the influence of pH and UV irradiation on the UV-VIS absorption spectra and photoluminescence
Authors: Baibarac Mihaela , Smaranda Ion , Nila Andreea , Serbschi Constantin 
Published: October 2019

AbstractUsing UV-VIS absorption spectroscopy, photoluminescence (PL) and photoluminescence excitation (PLE), the photodegradation reactions of folic acid (FA) in phosphate buffer (PB) solutions were studied. Regardless of the PB solution’s pH, the UV-VIS spectra showed a gradual decrease in absorbance at 284 nm simultaneous with an increase in the absorbance of another band in the spectral range of 320–380 nm, which was downshifted under UV irradiation. The relative intensity of the FA PL band, situated in the spectral range 375–600 nm, was dependent on the pH of the PB solution. The FA PL intensity increased as increasing UV irradiation time up to 281 min. in PB solutions with pH values of 6.4 and 5.4. Under an emission wavelength of 500 nm, the position of the FA PLE spectrum changed as the PB solution pH varied from 7 to 5.4 and the irradiation time increased to 317 min. These changes were correlated with the formation of two photodegradation products, namely, pterine-6-carboxylic acid and p-amino-benzoyl-L-glutamic acid. According to UV-VIS spectroscopy and PL and PLE studies, the presence of various excipients in commercial pharmaceutical tablets does not affect the photodegradation of FA in PB solutions. Using IR spectroscopy, new evidences for the formation of the two photodegradation products of FA in PB solutions are shown.
High-resolution Imaging of the Human Cochlea through the Round Window by means of Optical Coherence Tomography
Authors: Starovoyt Anastasiya , Putzeys Tristan , Wouters Jan , Verhaert Nicolas 
Published: October 2019

AbstractThe human cochlea is deeply embedded in the temporal bone and surrounded by a thick otic capsule, rendering its internal structure inaccessible for direct visualization. Clinical imaging techniques fall short of their resolution for imaging of the intracochlear structures with sufficient detail. As a result, there is a lack of knowledge concerning best practice for intracochlear therapy placement, such as cochlear implantation. In the past decades, optical coherence tomography (OCT) has proven valuable for non-invasive, high-resolution, cross-sectional imaging of tissue microstructure in various fields of medicine, including ophthalmology, cardiology and dermatology. There is an upcoming interest for OCT imaging of the cochlea, which so far was mostly carried out in small animals. In this temporal bone study, we focused on high-resolution imaging of the human cochlea. The cochlea was approached through mastoidectomy and posterior tympanotomy, both standard surgical procedures. A commercially available spectral-domain OCT imaging system was used to obtain high-resolution images of the cochlear hook region through the intact round window membrane in four cadaveric human temporal bones. We discuss the qualitative and quantitative characteristics of intracochlear structures on OCT images and their importance for cochlear implant surgery.
Microsurgical Resection of Multiple Giant Glomus Tumors
Authors: Ceccato Guilherme H. W. , Rassi Marcio S. , Borba Luis A. B. 
Published: October 2019

AbstractGlomus tumors, also called paragangliomas, are challenging lesions, demanding accurate knowledge of complex anatomy and pertinent approaches. We present the case of a 39-year-old male presenting with headache, vertigo, tinnitus, hearing loss, and hoarseness. Neurological assessment showed facial paralysis House–Brackmann IV and lower cranial nerves deficits. Preoperative magnetic resonance imaging (MRI) demonstrated two large lesions, suggestive of a glomus jugulare, and carotid body paragangliomas. Considering worsening of the symptoms and the important mass effect of both lesions over the neurovascular structures, microsurgical excision was offered, after preoperative tumor embolization. We preferred to approach both lesions in the same operation, starting by the cervical tumor. Initially there was not an easily identifiable dissection plane between the tumor and the carotid artery, but it was achieved after performing a subadventitial dissection, being possible to resect the entire lesion. The jugular foramen lesion was approached through a postauricular transtemporal approach, skeletonizing the sigmoid sinus, jugular bulb, and facial nerve, following a complete mastoidectomy. The tumor, extending to the intradural compartment, middle ear, internal auditory canal, petrous internal carotid artery, and internal jugular vein was completely removed. Postoperative MRI demonstrated complete resection of both lesions, and pathology confirmed to be paragangliomas. In the immediate postoperative period, the facial paralysis evolved to House–Brackmann grade VI, improving to grade III during follow-up. The patient underwent a vocal cord medialization in order to improve voice quality and swallowing. These are challenging lesions and extensive laboratory training is mandatory to be familiarized with the regional anatomy and its various surgical approaches.The link to the video can be found at: https://youtu.be/gA_ckwFq_9c.
Integrating physics demonstrations in undergraduate audiology classroom
Authors: Özmen Kübra 
Published: October 2019

Abstract
This paper focuses on the potential benefits of integrating physics demonstrations as a mediator for learning the physics of sound, acoustics and psychoacoustics in an undergraduate audiology classroom. The participants of this study were 54 first-year audiology students enrolled in the Physics of Sound and Acoustics course. According to the results, students’ physics achievement in a paper-pencil test (midterm exam) was found to be a good predictor for the good understanding of psychoacoustics. However, the results of a multiple regression analysis showed that student’s performance in physics demonstrations also mediate the process of learning in this course.
Learning mathematics through mathematical modeling approach using jembatan musi 2 context
Authors: Riyanto Bambang , Zulkardi  , Ilma Indra Putri Ratu , Darmawijoyo  
Published: October 2019

Abstract
Mathematics becomes more meaningful for students with modeling, and students are interested in this approach. The purpose of this study is how is the modeling of high school mathematics using the context of Jembatan Musi 2 taught in high schools?. This study used design research. Based on pilot teaching, learning experiments, and retrospective analysis learning devices and students worksheet are obtained for teachers teaching mathematical modeling, using the context of Jembatan Musi 2.
Students problem-solving abilities using the problem-based learning model with a metacognitive approach
Authors: Panjaitan Simon M , Hutauruk A JB 
Published: October 2019

Abstract
This article is about research on the study of improving students’ problem-solving abilities in the learning process using the Problem Based Learning learning model with the Metacognitive approach. This article also contains a study of the interaction between the learning model and the students’ mathematical prior knowledge towards problem-solving abilities, and the study of student behavior in improving mathematical problem-solving skills. The research uses quantitative research methods with research subjects students in the experimental class and the control class. The research instrument consisted of tests of mathematical problem-solving abilities, observation sheets, and interview guidelines. Research findings include (1) the learning model used does not have a significant difference in mathematical problem-solving skills, both overall and based on prior mathematical knowledge, (2) the learning model used does not have a significant effect on improving mathematical problem-solving abilities, both overall and based on mathematical prior experience, and (3) there is no interaction between learning models and mathematical prior knowledge to improve mathematical problem solving abilities.
Students mathematical literacy abilities in solving PISA type math problem with LRT context
Authors: Hardianti S , Zulkardi Z 
Published: October 2019

Abstract
One of the issues in mathematics education was many math problems requiring reasoning skills were included in the National Examination. This was part of the attempts to gradually adjust Indonesian standards to international standards such as PISA. The purpose of this article was to assess the potential effects of PISA-type math problem on students’ math literacy abilities. The method used in this article was design research type development studies, which consist of 2 stages, preliminary and formative evaluation. The preliminary stage consists of analysis and design. In the formative assessment consists of self-evaluations, expert reviews, one-to-one, small groups, and field tests. The potential effect of the problem was indicated by the results in the field test stage. The mathematical literacy abilities that emerge were communication skills, mathematics, representation, reasoning, and arguments, choosing strategies in solving problems, and the ability to use language, symbolic, formal, and technical operations. Communication skills dominate over other mathematical literacy abilities.
Virtual manipulatives media in mathematical abstraction
Authors: Hakim L L , Alghadari F , Widodo S A 
Published: October 2019

Abstract
By the characteristics of mathematics, which has the object of study is abstract, then the abstraction becomes an important part that can not be separated from mathematics. The development of abstraction theories, either directly or not, will be closely related to the process of learning mathematics in the classroom. Also, the rapid development of virtual manipulatives media in the world of mathematics education can bring a good influence on the learning process that takes place in the classroom. In this regard, this paper aims to examine theories of abstraction in mathematics and its possible implementation in mathematics education which is integrated with virtual manipulatives media to provide a choice to overcome various problems of learning mathematics. In the world of mathematics education, some abstract concepts in mathematics will be more easily learned through empirical abstraction processes such as introducing the concept of positive integers in students. However, when abstract concepts are not allowed to be empirically introduced to the students, the role of virtual manipulatives media can be one of the alternatives to choose from. Also, virtual media manipulatives can be utilized to facilitate the process of reflective abstraction and theoretical abstraction
Students’ critical ability of mathematics based on cognitive styles
Authors: Dwi Susandi Ardi , Sa’dijah Cholis , Rahman As’ari Abdur , Susiswo  
Published: October 2019

Abstract
The strategies used in solving problems can be influenced by cognitive style. This research is a qualitative descriptive study. The purpose of this study was to describe the mathematical critical thinking skills of junior high school students based on the cognitive style of Dependent Field and cognitive style Field Independent in solving SPLDV problems. The subject of this study consisted of 1 student who had the field-dependent cognitive style and 1 student who had the field-independent cognitive style chosen by purposive sampling. Data collection techniques were carried out by administering the cognitive style test of the Embedded Figure Test Group, mathematical problem-solving tests, interview guidelines, and documentation. Data were analyzed based on FRISCO critical thinking category indicators (Focus, Reason, Inference, Situation, Clarity, and Overview) in each step of problem-solving, namely understanding problems, arranging plans, implementing plans, and checking again. Data analysis is done by reducing data, presenting data, and drawing conclusions. The results showed that students who had the cognitive style of field-dependent and students who had the cognitive style FI had good critical thinking skills in each step of problem-solving according to Polya.
Improving mathematical habits of mind prospective teachers using metacognitive approach
Authors: Sugandi A.I. , Maya R. , Hutajulu M. 
Published: October 2019

Abstract
Research studied for examine differences in habits of mind students’ candidate teacher between the learners use metacognitive approach with usually approach. Method in this research was a quasi-experiment, because existence manipulation treatment in the form of gift metacognitive approach. Population in research is all students candidate teacher at IKIP Siliwangi, while the sample selected two class from force in 2016. The instrument used in research was a set of questionnaire which contains 32 question. Processing data entirely use Microsoft Excel and SPSS 22. From the results data processing obtained conclusion that habits of mind students’ candidate teacher whose learning using metacognitive approach better than from usually approach
Trends for ‘wiskunde’ or ‘wiskunst’? the case of students’ problem solving on elementary math problem (a little practical review from ‘revisiting mathematics education’)
Authors: Yulianto E , Santika S , Arumsari C , Turmudi  
Published: October 2019

Abstract
This paper is a little practical reflection of the idea proposed by Freudenthal in his book titled ‘Revisiting Mathematics Education’. Theoretically, a fundamental study of more philosophical mathematical meanings was discussed by Freudenthal through the terms ‘wiskunde’ and ‘wiskunst’. In essence, wiskunde means mathematics as an exact science, while wiskunst means an art in mathematics and science. Although there has been a lot of research that shows the success of RME in learning, the results of research that can contrast explicitly how the wiskunde and wiskunst phenomena work in the process of solving mathematical problems are still rarely found. This study aims to see the tendency of students towards the phenomenon of wiskunde or wiskunst in working on elementary math problems then describe the psychological factors and impacts that might be influential. This study used literature review and qualitative methods through the interview process for students who were given two elementary school math problems. Four out of forty students from fourth semester were chosen to be interview respondents to represent variations of the unique answers. Data analysis was carried out through a hermeneutic approach to student answers and interview transcripts. Research shows that the wiskunde phenomenon looks more dominant than wiskunst. This is thought to be related to the symptoms of psychological blockages of student’s college who are predominantly working on elementary math problems still using the very formal formulas, they should still be able to show a way of thinking like an elementary school kid. The impact of this wiskunde tendency indicates the ‘matherate’ of students who have become blunt. The contrast of wiskunde and wiskunst’s character and its reflection to the philosophy of education are discussed boldly in this paper.
Obstacles in Constructing Geometrical Proofs of Mathematics-Teacher-Students Based on Boero’s Proving Model
Authors: Maarif S , Perbowo K S , Noto M S , Harisman Y 
Published: October 2019

Abstract
This study aimed at identifying the obstacles of mathematics-teacher-students based on Boero’s proving model. This study was conducted using a mix method by applying sequential explanatory strategy. The stages of the research were carried out by taking the quantitative data and revealing the qualitative data using semi-structured interviews. In the result of this study, it was found that most of mathematics-teacher-students had difficulties in constructing geometrical proofs of each Boero’s proving model. Even in the phase of writing formal proof, there were only 6.67% of students could write fully in the cases of indirect proving. There were 13.33% of students in the cases of direct proving. This study concluded several obstacles which students faced in constructing the geometrical proofs formally in each phase of Boero’ proving model. The obstacles included: the difficulty in making a diagrammatic sketch of conjecture which was completely made with the correct geometrical notation; the difficulty in knowing of cause-effect of geometrical problems to be proved, if it involved some conditional sentences; inability to write a conjecture made in the form of geometrical symbols, formulas and axiomatic deduction; the difficulty in selecting a valid statement of the conjecture made and the difficulty in writing formal proof.