bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pengembangan Soal Open-Ended Pokok Bahasan Barisan dan Deret Bilangan untuk Siswa SMP
Authors: Yusliriadi Yusliriadi , Darmawijoyo Darmawijoyo , Somakim Somakim 
Published: February 2018

The research is proposed to: (1) get open-ended problems which are valid and practice on the math topic Sequence and Series of numbers for junior high school students. (2) find potential effects of open ended problems to the students on the topic about sequence and series of numbers. The methodology that use in this study is a developmental research. The way of collecting data is by using Walk through, to determine the validity of the matter is the content, construct, and language; document at small group to know about the practicality; tests and interviews to find out about the potential effects on the ability of students' understanding of the concept. The result of data analysis come to conclusion, that: (1) This research produces (six question) open ended problems on the topic of sequence and series of numbers for students of IX grade are valid and practice. (2) The prototype of open-ended problems which was developed have positive potential effect to the ability of studentsâ€™ understanding of the concept, it is shown by the average value of studentsâ€™ understanding of the concept of good in the open-ended problems test which resulted 71,9%.
Pengembangan Perangkat Pembelajaran Aritmetika Sosial Berbasis Problem Based Learning di Kelas VII SMP
Authors: Ridwan Ruslan , Zulkardi Zulkardi , Darmawijoyo Darmawijoyo 
Published: February 2018

The purpose of this study is aimeds to (1) produce the mathematics lesson plan based on social arithmetic Problem Based Learning (PBL) in class VII in viewed from the aspects of validity and practicality and to know the potential effects arising from the development of the lesson plan, (2) describe the characteristics of the lesson plan based on social arithmetic Problem Based Learning. The method of the study was the development research according to the type of formative research by Tessmer. The stages of development were Self Evaluation, prototyping and product. The subjects were VII.1 grade students of SMP Negeri 1 Muaradua semester 2014/2015 academic year, consistive of 31 people. Data collection techniques used were documentation, walk-throughs, observation sheets, and test results. Data were analyzed qualitatively and quantitatively. The results of data analysis showed that in the mathematics lesson plan based on social arithmetic Problem Based Learning (PBL) were valid, practical, and had a potential effect. The lesson plan had a valid learning in the content, construct, and language experts based on the results of the validation stage of the expert review and the prototype test on a small group stage, while the practical lesson plan obtained from the revised test results of one-to-one and small group. Potential effects of the lesson plan was known from the results of the field test and the results of the student's final test. The results of the student's final test showed 45.16% of the students were is very good category, 32.26% were good category, and 22.58% fair category. From the result of observation, the percentage average of studentsâ€™ activity was above 81,25% included in very good category.
Pengembangan Soal Matematika Berkarakteristik TIMSS Tipe Pemecahan Masalah pada Topik Geometri Pengukuran Volume Kubus dan Balok Kelas VIII
Authors: Pratiwi Ika , Zulkardi Zulkardi , Susanti Ely 
Published: February 2018

This research aims to produce a TIMSS characterized math problems that are valid and reliable. The method of this research is Design Research. The sample of this study were 31 students of SMP Negeri 1 Inderalaya. The procedure of this study through the stages of Preliminary Evaluation and Formative Evaluation. Based on the results obtained 7 of TIMSS characterized with characteristics (1) using real-life contexts, (2) using characteristics of TIMSS, and (3) the type of problem-solving that problem logically and empirically valid and reliable. Valid logically be fulfilled from the results of the assessment validator, where the validator comment on the terms of the content, construct, and language. Valid empirically criteria for both internally for items validity and externally for the whole items validity. Items also expressed reliable with a high level of confidence as the test instrument through items with the analysis result reliability coefficient of 0,703.
Self Efficacy Mahasiswa terhadap Matematika dan Pembelajaran Berbasis Kegiatan Lesson Study
Authors: Risnanosanti Risnanosanti 
Published: February 2018

The aim of this research is to description about undergraduate students self efficacy toward mathematics in learning based on lesson study activity. This studied done in mathematics study program of FKIP Muhammadiyah University of Bengkulu in academic year 2015/2016. The subject in this research are undergraduate students whose studied education statistic about 31 students. The instruments are observation sheet and self efficacy scale. The method in this research come from lesson research with lesson study and have three stages namely plan, do and see. This researched have 4 cycles. Based on data analysis the result of this research is undergraduate student self efficacy is in very good category.
Extended middle fossa approach to lateralized pontine cavernomas in children
Authors: Rennert Robert C. , Hoshide Reid , Calayag Mark , Kemp Joanna , Gonda David D. , Meltzer Hal S. , Fukushima Takanori , Day John D. , Levy Michael L. 
Published: February 2018

OBJECTIVETreatment of hemorrhagic cavernous malformations within the lateral pontine region demands meticulous surgical planning and execution to maximize resection while minimizing morbidity. The authors report a single institution’s experience using the extended middle fossa rhomboid approach for the safe resection of hemorrhagic cavernomas involving the lateral pons.METHODSA retrospective chart review was performed to identify and review the surgical outcomes of patients who underwent an extended middle fossa rhomboid approach for the resection of hemorrhagic cavernomas involving the lateral pons during a 10-year period at Rady Children’s Hospital of San Diego. Surgical landmarks for this extradural approach were based on the Fukushima dual-fan model, which defines the rhomboid based on the following anatomical structures: 1) the junction of the greater superficial petrosal nerve (GSPN) and mandibular branch of the trigeminal nerve; 2) the lateral edge of the porus trigeminus; 3) the intersection of the petrous ridge and arcuate eminence; and 4) the intersection of the GSPN, geniculate ganglion, and arcuate eminence. The boundaries of maximal bony removal for this approach are the clivus inferiorly below the inferior petrosal sinus; unroofing of the internal auditory canal posteriorly; skeletonizing the geniculate ganglion, GSPN, and internal carotid artery laterally; and drilling under the Gasserian ganglion anteriorly. This extradural petrosectomy allowed for an approach to all lesions from an area posterolateral to the basilar artery near its junction with cranial nerve (CN) VI, superior to the anterior inferior cerebellar artery and lateral to the origin of CN V. Retraction of the mandibular branch of the trigeminal nerve during this approach allowed avoidance of the region involving CN IV and the superior cerebellar artery.RESULTSEight pediatric patients (4 girls and 4 boys, mean age of 13.2 ± 4.6 years) with hemorrhagic cavernomas involving the lateral pons and extension to the pial surface were treated using the surgical approach described above. Seven cavernomas were completely resected. In the eighth patient, a second peripheral lesion was not resected with the primary lesion. One patient had a transient CN VI palsy, and 2 patients had transient trigeminal hypesthesia/dysesthesia. One patient experienced a CSF leak that was successfully treated by oversewing the wound.CONCLUSIONSThe extended middle fossa approach can be used for resection of lateral pontine hemorrhagic cavernomas with minimal morbidity in the pediatric population.
Risk of intracranial hemorrhage after carotid artery stenting versus endarterectomy: a population-based study
Authors: Hussain Mohamad A. , Alali Aziz S. , Mamdani Muhammad , Tu Jack V. , Saposnik Gustavo , Salata Konard , Nathens Avery B. , de Mestral Charles , Bhatt Deepak L. , Verma Subodh , Al-Omran Mohammed 
Published: February 2018

OBJECTIVEIntracranial hemorrhage (ICH) associated with cerebral hyperperfusion syndrome is a rare but major complication of carotid artery revascularization. The objective of this study was to compare the rate of ICH after carotid artery stenting (CAS) with that after endarterectomy (CEA).METHODSThe authors performed a retrospective population-based cohort study of patients who underwent carotid artery revascularization in the province of Ontario, Canada, between 2002 and 2015. The primary outcome was the rate of ICH that occurred within 90 days after carotid artery intervention among patients who underwent CAS versus that of those who underwent CEA. The authors used inverse probability of treatment weighting and propensity scores to account for selection bias. In sensitivity analyses, patients who had postprocedure ischemic stroke were excluded, and the following subgroups were examined: patients with symptomatic and asymptomatic carotid artery stenosis, patients treated between 2010 and 2015, and patients aged ≥ 66 years (to account for antiplatelet and anticoagulant use).RESULTSA total of 16,688 patients underwent carotid artery revascularization (14% CAS, 86% CEA). Patients with more comorbid illnesses, symptomatic carotid artery stenosis, or cardiac disease and those who were taking antiplatelet agents or warfarin before surgery were more likely to undergo CAS. Among the overall cohort, 80 (0.48%) patients developed ICH within 90 days (0.85% after CAS, 0.42% after CEA). The 180-day mortality rate after ICH in the overall cohort was 2.7%, whereas the 180-day mortality rate among patients who suffered ICH was 42.5% (40% for CAS-treated patients, 43.3% for CEA-treated patients). In the adjusted analysis, patients who underwent CAS were significantly more likely to have ICH than those who underwent CEA (adjusted OR 1.77; 95% CI 1.32–2.36; p < 0.001). These results were consistent after excluding patients who developed postprocedure ischemic stroke (adjusted OR 1.90; 95% CI 1.41–2.56) and consistent among symptomatic (adjusted OR 1.74; 95% CI 1.16–2.63) and asymptomatic (adjusted OR 1.75; 95% CI 1.16–2.63) patients with carotid artery stenosis, among patients treated between 2010 and 2015 (adjusted OR 2.21; 95% CI 1.45–3.38), and among the subgroup of patients aged ≥ 66 years (adjusted OR 1.53; 95% CI 1.05–2.24) after adjusting for medication use.CONCLUSIONSCAS is associated with a rare but higher risk of ICH relative to CEA. Future research is needed to devise strategies that minimize the risk of this serious complication after carotid artery revascularization.
Endoscopic anterior transmaxillary “transalisphenoid” approach to Meckel’s cave and the middle cranial fossa: an anatomical study and clinical application
Authors: Truong Huy Q. , Sun Xicai , Celtikci Emrah , Borghei-Razavi Hamid , Wang Eric W. , Snyderman Carl H. , Gardner Paul A. , Fernandez-Miranda Juan C. 
Published: February 2018

OBJECTIVEMultiple approaches have been designed to reach the medial middle fossa (for lesions in Meckel’s cave, in particular), but an anterior approach through the greater wing of the sphenoid (transalisphenoid) has not been explored. In this study, the authors sought to assess the feasibility of and define the anatomical landmarks for an endoscopic anterior transmaxillary transalisphenoid (EATT) approach to Meckel’s cave and the middle cranial fossa.METHODSEndoscopic dissection was performed on 5 cadaver heads injected intravascularly with colored silicone bilaterally to develop the approach and define surgical landmarks. The authors then used this approach in 2 patients with tumors that involved Meckel’s cave and provide their illustrative clinical case reports.RESULTSThe EATT approach is divided into the following 4 stages: 1) entry into the maxillary sinus, 2) exposure of the greater wing of the sphenoid, 3) exposure of the medial middle fossa, and 4) exposure of Meckel’s cave and lateral wall of the cavernous sinus. The approach provided excellent surgical access to the anterior and lateral portions of Meckel’s cave and offered the possibility of expanding into the infratemporal fossa and lateral middle fossa and, in combination with an endonasal transpterygoid approach, accessing the anteromedial aspect of Meckel’s cave.CONCLUSIONSThe EATT approach to Meckel’s cave and the middle cranial fossa is technically feasible and confers certain advantages in specific clinical situations. The approach might complement current surgical approaches for lesions of Meckel’s cave and could be ideal for lesions that are lateral to the trigeminal ganglion in Meckel’s cave or extend from the maxillary sinus, infratemporal fossa, or pterygopalatine fossa into the middle cranial fossa, Meckel’s cave, and cavernous sinus, such as schwannomas, meningiomas, and sinonasal tumors and perineural spread of cutaneous malignancy.
Effect of treatment period on outcomes after stereotactic radiosurgery for brain arteriovenous malformations: an international multicenter study
Authors: Patibandla Mohana Rao , Ding Dale , Kano Hideyuki , Starke Robert M. , Lee John Y. K. , Mathieu David , Whitesell Jamie , Pierce John T. , Huang Paul P. , Kondziolka Douglas , Feliciano Caleb , Rodriguez-Mercado Rafael , Almodovar Luis , Grills Inga S. , Silva Danilo , Abbassy Mahmoud , Missios Symeon , Barnett Gene H. , Lunsford L. Dade , Sheehan Jason P. 
Published: February 2018

OBJECTIVEThe role of and technique for stereotactic radiosurgery (SRS) in the management of arteriovenous malformations (AVMs) have evolved over the past four decades. The aim of this multicenter, retrospective cohort study was to compare the SRS outcomes of AVMs treated during different time periods.METHODSThe authors selected patients with AVMs who underwent single-session SRS at 8 different centers from 1988 to 2014 with follow-up ≥ 6 months. The SRS eras were categorized as early (1988–2000) or modern (2001–2014). Statistical analyses were performed to compare the baseline characteristics and outcomes of the early versus modern SRS eras. Favorable outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes (RICs).RESULTSThe study cohort comprised 2248 patients with AVMs, including 1584 in the early and 664 in the modern SRS eras. AVMs in the early SRS era were significantly smaller (p < 0.001 for maximum diameter and volume), and they were treated with a significantly higher radiosurgical margin dose (p < 0.001). The obliteration rate was significantly higher in the early SRS era (65% vs 51%, p < 0.001), and earlier SRS treatment period was an independent predictor of obliteration in the multivariate analysis (p < 0.001). The rates of post-SRS hemorrhage and radiological, symptomatic, and permanent RICs were not significantly different between the two groups. Favorable outcome was achieved in a significantly higher proportion of patients in the early SRS era (61% vs 45%, p < 0.001), but the earlier SRS era was not statistically significant in the multivariate analysis (p = 0.470) with favorable outcome.CONCLUSIONSDespite considerable advances in SRS technology, refinement of AVM selection, and contemporary multimodality AVM treatment, the study failed to observe substantial improvements in SRS favorable outcomes or obliteration for patients with AVMs over time. Differences in baseline AVM characteristics and SRS treatment parameters may partially account for the significantly lower obliteration rates in the modern SRS era. However, improvements in patient selection and dose planning are necessary to optimize the utility of SRS in the contemporary management of AVMs.
Increase in callosal angle and decrease in ventricular volume after shunt surgery in patients with idiopathic normal pressure hydrocephalus
Authors: Virhammar Johan , Laurell Katarina , Cesarini Kristina Giuliana , Larsson Elna-Marie 
Published: February 2018

OBJECTIVEPostoperative decrease in ventricle size is usually not detectable either by visual assessment or by measuring the Evans index in patients with idiopathic normal pressure hydrocephalus (iNPH). The aim of the present study was to investigate whether the angle between the lateral ventricles (the callosal angle [CA]) increases and ventricular volume decreases after shunt surgery in patients with iNPH.METHODSMagnetic resonance imaging of the brain was performed before and 3 months after shunt surgery in 18 patients with iNPH. The CA and Evans index were measured on T1-weighted 3D MR images, and ventricular volume contralateral to the shunt valve was measured with quantitative MRI.RESULTSThe CA was larger postoperatively (mean 78°, 95% CI 69°–87°) than preoperatively (mean 67°, 95% CI 60°–73°; p < 0.001). The volume of the lateral ventricle contralateral to the shunt valve decreased from 73 ml (95% CI 66–80 ml) preoperatively to 63 ml (95% CI 54–72 ml) postoperatively (p < 0.001). The Evans index was 0.365 (95% CI 0.35–0.38) preoperatively and 0.358 (95% CI 0.34–0.38) postoperatively (p < 0.05). Postoperative change of CA showed a negative correlation with change of ventricular volume (r = −0.76, p < 0.01).CONCLUSIONSIn this sample of patients with iNPH, the CA increased and ventricular volume decreased after shunt surgery. The relative difference was most pronounced for the CA, indicating that this accessible, noninvasive radiological marker should be evaluated further as an indirect method to determine shunt function in patients with iNPH.
Probing Extragalactic Planets Using Quasar Microlensing
Authors: Dai Xinyu , Guerras Eduardo 
Published: February 2018

Abstract
Previously, planets have been detected only in the Milky Way galaxy. Here, we show that quasar microlensing provides a means to probe extragalactic planets in the lens galaxy, by studying the microlensing properties of emission close to the event horizon of the supermassive black hole of the background quasar, using the current generation telescopes. We show that a population of unbound planets between stars with masses ranging from Moon to Jupiter masses is needed to explain the frequent Fe Kα line energy shifts observed in the gravitationally lensed quasar RXJ 1131–1231 at a lens redshift of z = 0.295 or 3.8 billion lt-yr away. We constrain the planet mass-fraction to be larger than 0.0001 of the halo mass, which is equivalent to 2000 objects ranging from Moon to Jupiter mass per main-sequence star.
K2 Reveals Pulsed Accretion Driven by the 2 Myr Old Hot Jupiter CI Tau b
Authors: Biddle Lauren I. , Johns-Krull Christopher M. , Llama Joe , Prato Lisa , Skiff Brian A. 
Published: February 2018

Abstract
CI Tau is a young (∼2 Myr) classical T Tauri star located in the Taurus star-forming region. Radial velocity observations indicate it hosts a Jupiter-sized planet with an orbital period of approximately 9 days. In this work, we analyze time series of CI Tau’s photometric variability as seen by K2. The light curve reveals the stellar rotation period to be ∼6.6 days. Although there is no evidence that CI Tau b transits the host star, a ∼9 day signature is also present in the light curve. We believe this is most likely caused by planet–disk interactions that perturb the accretion flow onto the star, resulting in a periodic modulation of the brightness with the ∼9 day period of the planet’s orbit.
The Impact of Crustal Magnetic Fields on the Thermal Structure of the Martian Upper Atmosphere
Authors: Cui J. , Yelle R. V. , Zhao L.-L. , Stone S. , Jiang F.-Y. , Cao Y.-T. , Yao M.-J. , Koskinen T. T. , Wei Y. 
Published: February 2018

Abstract
Using the Mars Atmosphere and Volatile Evolution Neutral Gas and Ion Mass Spectrometer data, we investigate the possible impact of crustal magnetic fields on the thermal structure of the Martian upper atmosphere. Our analysis reveals a clear enhancement in temperature over regions with strong crustal magnetic fields during two deep dip campaigns covering the periods of April 17–22 and September 2–8, both in 2015. Several controlling factors, such as solar EUV irradiance, relative atomic O abundance, and non-migrating tides, do not help to explain the observed temperature enhancement, and a magnetically driven scenario is favored. We evaluate the roles of several heating mechanisms that are likely modulated by the presence of crustal magnetic fields, including Joule heating, ion chemical heating, as well as electron impact heating via either precipitating solar wind electrons or locally produced photoelectrons. The respective heating rates of these mechanisms are substantially lower than the solar EUV heating rate, implying that none of them is able to interpret the observations.
Integral Field Spectroscopy of Supernova Remnant 1E0102–7219 Reveals Fast-moving Hydrogen and Sulfur-rich Ejecta
Authors: Seitenzahl Ivo R. , Vogt Frédéric P. A. , Terry Jason P. , Ghavamian Parviz , Dopita Michael A. , Ruiter Ashley J. , Sukhbold Tuguldur 
Published: February 2018

Abstract
We study the optical emission from heavy element ejecta in the oxygen-rich young supernova remnant 1E 0102.2–7219 (1E 0102) in the Small Magellanic Cloud. We have used the Multi-Unit Spectroscopic Explorer optical integral field spectrograph at the Very Large Telescope on Cerro Paranal and the wide field spectrograph (WiFeS) at the ANU 2.3 m telescope at Siding Spring Observatory to obtain deep observations of 1E 0102. Our observations cover the entire extent of the remnant from below 3500 Å to 9350 Å. Our observations unambiguously reveal the presence of fast-moving ejecta emitting in [S ii], [S iii], [Ar iii], and [Cl ii]. The sulfur-rich ejecta appear more asymmetrically distributed compared to oxygen or neon, a product of carbon burning. In addition to the forbidden line emission from products of oxygen burning (S, Ar, Cl), we have also discovered Hα and Hβ emission from several knots of low surface brightness, fast-moving ejecta. The presence of fast-moving hydrogen points toward a progenitor that had not entirely shed its hydrogen envelope prior to the supernova. The explosion that gave rise to 1E 0102 is therefore commensurate with a Type IIb supernova.
The Hubble Constant from SN Refsdal
Authors: Vega-Ferrero J. , Diego J. M. , Miranda V. , Bernstein G. M. 
Published: February 2018

Abstract

Hubble Space Telescope observations from 2015 December 11 detected the expected fifth counter-image of supernova (SN) Refsdal at z = 1.49. In this Letter, we compare the time-delay predictions from numerous models with the measured value derived by Kelly et al. from very early data in the light curve of the SN Refsdal and find a best value for

(68% CL), in excellent agreement with predictions from cosmic microwave background and recent weak lensing data + baryon acoustic oscillations + Big Bang nucleosynthesis (from the DES Collaboration). This is the first constraint on H
0 derived from time delays between multiple-lensed SN images, and the first with a galaxy cluster lens, subject to systematic effects different from other time-delay H
0 estimates. Additional time-delay measurements from new multiply imaged SNe will allow derivation of competitive constraints on H
0.