bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kemampuan berpikir tingkat tinggi siswa SMP di Kabupaten Jember dalam menyelesaikan soal berstandar PISA
Authors: Kurniati Dian , Harimukti Romi , Jamil Nur Asiyah 
Published: December 2016

Tujuan penelitian ini adalah mendeskripsikan kemampuan berpikir tingkat tinggi (Higher Order Thinking Skills/HOTS) siswa dalam menyelesaikan soal PISA berdasarkan indikator yang telah disusun. Kemampuan berpikir tingkat tinggi dalam penelitian ini meliputi kemampuan logika dan penalaran, analisis, evaluasi, serta kreasi. Penelitian ini merupakan penelitian deskriptif dengan pendekatan kualitatif. Metode pengumpulan data meliputi metode dokumentasi, tes, dan wawancara. Hasil penelitian dari 30 siswa yang tersebar di beberapa SMP di Kabupaten Jember didapatkan bahwa 18 siswa mampu melakukan kemampuan logika dan penalaran, analisis, evaluasi, serta kreasi dengan baik dalam menyelesaikan beberapa soal, sehingga tergolong memiliki kemampuan berpikir tingkat tinggi dengan level sedang. Selanjutnya, 12 siswa tidak mampu melakukan kemampuan analisis, evaluasi, kreasi, logika dan penalaran dengan baik dalam menyelesaikan semua soal, sehingga tergolong memiliki kemampuan berpikir tingkat tinggi dengan level rendah.Kata kunci: PISA, kemampuan logika dan penalaran, kemampuan analisis, evaluasi, kreasi THE HIGHER ORDER THINKING SKILLS OF JUNIOR HIGH SCHOOL STUDENTS AT JEMBER DISTRICT IN SOLVING PISA STANDAR-BASED TEST ITEMAbstractThe purpose of this research was to describe the higher order thinking skills of students in solving PISA standar-based test item based on indicators that had been compiled. The indicators in this research were the ability of logic and reasoning, analysis, evaluation, and creation. This research is a descriptive qualitative approach. The data collection methods in this research were documentation, test, and interview. From 30 students spread across many Junior High Scoolls in Jember district, 18 students are found to be able to perform logic skills and reasoning, analysis, evaluation, and creation well in resolving some of the problems, thus classified as having high level thinking skills with moderate level. Furthermore, 12 students are not able to perform analytical skills, evaluation, creation, logic and reasoning well in solving all the problems, so they are considered to have low level high order thinking skill.Keywords: PISA, logic and reasoning, analysis, evaluation, creation skills
DEVELOPING ATMOSPHERIC RETRIEVAL METHODS FOR DIRECT IMAGING SPECTROSCOPY OF GAS GIANTS IN REFLECTED LIGHT. I. METHANE ABUNDANCES AND BASIC CLOUD PROPERTIES
Authors: Lupu Roxana E. , Marley Mark S. , Lewis Nikole , Line Michael , Traub Wesley A. , Zahnle Kevin 
Published: December 2016

ABSTRACT
Upcoming space-based coronagraphic instruments in the next decade will perform reflected light spectroscopy and photometry of cool directly imaged extrasolar giant planets. We are developing a new atmospheric retrieval methodology to help assess the science return and inform the instrument design for such future missions, and ultimately interpret the resulting observations. Our retrieval technique employs a geometric albedo model coupled with both a Markov chain Monte Carlo Ensemble Sampler (emcee) and a multimodal nested sampling algorithm (MultiNest) to map the posterior distribution. This combination makes the global evidence calculation more robust for any given model and highlights possible discrepancies in the likelihood maps. As a proof of concept, our current atmospheric model contains one or two cloud layers, methane as a major absorber, and a H2–He background gas. This 6-to-9 parameter model is appropriate for Jupiter-like planets and can be easily expanded in the future. In addition to deriving the marginal likelihood distribution and confidence intervals for the model parameters, we perform model selection to determine the significance of methane and cloud detection as a function of expected signal-to-noise ratio in the presence of spectral noise correlations. After internal validation, the method is applied to realistic spectra of Jupiter, Saturn, and HD 99492c, a model observing target. We find that the presence or absence of clouds and methane can be determined with high confidence, while parameter uncertainties are model dependent and correlated. Such general methods will also be applicable to the interpretation of direct imaging spectra of cloudy terrestrial planets.
K2 DISCOVERS A BUSY BEE: AN UNUSUAL TRANSITING NEPTUNE FOUND IN THE BEEHIVE CLUSTER
Authors: Obermeier Christian , Henning Thomas , Schlieder Joshua E. , Crossfield Ian J. M. , Petigura Erik A. , Howard Andrew W. , Sinukoff Evan , Isaacson Howard , Ciardi David R. , David Trevor J. , Hillenbrand Lynne A. , Beichman Charles A. , Howell Steve B. , Horch Elliott , Everett Mark , Hirsch Lea , Teske Johanna , Christiansen Jessie L. , Lépine Sébastien , Aller Kimberly M. , Liu Michael C. , Saglia Roberto P. , Livingston John , Kluge Matthias 
Published: December 2016

ABSTRACT
Open clusters have been the focus of several exoplanet surveys, but only a few planets have so far been discovered. The Kepler spacecraft revealed an abundance of small planets around small cool stars, therefore, such cluster members are prime targets for exoplanet transit searches. Kepler's new mission, K2, is targeting several open clusters and star-forming regions around the ecliptic to search for transiting planets around their low-mass constituents. Here, we report the discovery of the first transiting planet in the intermediate-age (800 Myr) Beehive cluster (Praesepe). K2-95 is a faint (

)

dwarf from K2's Campaign 5 with an effective temperature of

, approximately solar metallicity and a radius of

. We detected a transiting planet with a radius of

and an orbital period of 10.134 days. We combined photometry, medium/high-resolution spectroscopy, adaptive optics/speckle imaging, and archival survey images to rule out any false-positive detection scenarios, validate the planet, and further characterize the system. The planet’s radius is very unusual as M-dwarf field stars rarely have Neptune-sized transiting planets. The comparatively large radius of K2-95b is consistent with the other recently discovered cluster planets K2-25b (Hyades) and K2-33b (Upper Scorpius), indicating systematic differences in their evolutionary states or formation. These discoveries from K2 provide a snapshot of planet formation and evolution in cluster environments and thus make excellent laboratories to test differences between field-star and cluster planet populations.
RADIAL VELOCITIES AND METALLICITIES OF RED GIANT STARS IN THE OLD OPEN CLUSTER NGC 7762
Authors: Carraro Giovanni , Semenko Eugene A. , Villanova Sandro 
Published: December 2016

ABSTRACT
We present and discuss radial velocity and the very first metallicity measurements for nine evolved stars in the poorly known old open cluster NGC 7762. We isolated eight radial velocity cluster members and one interloper. Radial velocities are in good agreement with previous studies. NGC 7762 turns out to be of solar metallicity within the uncertainties ([Fe/H] = 0.04 ± 0.12). For this metallicity, the cluster age is 2.5 ± 0.2 Gyr, and falls in an age range where only a few old open clusters are known. With respect to previous studies, we find a larger distance, implying the cluster is located

pc from the Sun. For most of the elements we measure solar-scaled abundance ratios. We searched the literature for open clusters of similar age in the solar vicinity and found that NGC 7762 can be considered a twin of Ruprecht 147, a similar age cluster located only 300 pc from the Sun. In fact, as well as age, metallicity and abundance ratios are very close to Ruprecht 147 values within the observational uncertainties.
A TRIP TO THE CATACLYSMIC BINARY ZOO: DETAILED FOLLOW-UP OF 35 RECENTLY DISCOVERED SYSTEMS
Authors: Thorstensen John R. , Alper Erek H. , Weil Kathryn E. 
Published: December 2016

ABSTRACT
We report follow-up studies of 35 recently discovered cataclysmic variables (CVs), 32 of which were found in large, automated synoptic sky surveys. The objects were selected for observational tractability. For 34 of the objects, we present mean spectra and spectroscopic orbital periods, and for one more we give an eclipse-based period. Thirty-two of the period determinations are new, and three of these refine published estimates based on superhump periods. The remaining three of our determinations confirm previously published periods. Twenty of the stars are confirmed or suspected dwarf novae with periods shorter than 3 hr, but we also find three apparent polars (AM Her stars) and six systems with

. Five of these systems have secondary stars visible in their spectra, from which we estimate distances when possible. The orbital period distribution of this sample is very similar to that of previously discovered CVs.
SHEAR ACCELERATION IN EXPANDING FLOWS
Authors: Rieger F. M. , Duffy P. 
Published: December 2016

ABSTRACT
Shear flows are naturally expected to occur in astrophysical environments and potential sites of continuous non-thermal Fermi-type particle acceleration. Here we investigate the efficiency of expanding relativistic outflows to facilitate the acceleration of energetic charged particles to higher energies. To this end, the gradual shear acceleration coefficient is derived based on an analytical treatment. The results are applied to the context of the relativistic jets from active galactic nuclei. The inferred acceleration timescale is investigated for a variety of conical flow profiles (i.e., power law, Gaussian, Fermi–Dirac) and compared to the relevant radiative and non-radiative loss timescales. The results exemplify that relativistic shear flows are capable of boosting cosmic-rays to extreme energies. Efficient electron acceleration, on the other hand, requires weak magnetic fields and may thus be accompanied by a delayed onset of particle energization and affect the overall jet appearance (e.g., core, ridge line, and limb-brightening).
REVISITING THE STRUCTURE AND SPECTRUM OF THE MAGNETIC-RECONNECTION-HEATED CORONA IN LUMINOUS AGNs
Authors: Liu J. Y. , Qiao E. L. , Liu B. F. 
Published: December 2016

ABSTRACT
It is believed that the hard X-ray emission in the luminous active galactic nuclei (AGNs) is from the hot corona above the cool accretion disk. However, the formation of the corona is still debated. Liu et al. investigated the spectrum of the corona heated by the reconnection of the magnetic field generated by dynamo action in the thin disk and emerging into the corona as a result of buoyancy instability. In the present paper, we improve this model to interpret the observed relation of the hard X-ray spectrum becoming softer at higher accretion rate in luminous AGNs. The magnetic field is characterized by

, i.e., the ratio of the sum of gas pressure and radiation pressure to the magnetic pressure in the disk (

). Besides, both the intrinsic disk photons and reprocessed photons by the disk are included as the seed photons for inverse Compton scattering. These improvements are crucial for investigating the effect of magnetic field on the accretion disk corona when it is not clear whether the radiation pressure or gas pressure dominates in the thin disk. We change the value of

in order to constrain the magnetic field in the accretion disk in luminous AGNs. We find that the energy fraction released in the corona (f) gradually increases with the decrease of

for the same accretion rate. When

decreases to less than 50, the structure and spectrum of the disk corona are independent of accretion rate, which is similar to the hard spectrum found in Liu et al. Comparing with the observational results of the hard X-ray bolometric correction factor in a sample of luminous AGNs, we suggest that the value of

is about 100–200 for α = 0.3, and the energy fraction f should be larger than 30% for hard X-ray emission.
THE BURSTY STAR FORMATION HISTORIES OF LOW-MASS GALAXIES AT 0.4 < z < 1 REVEALED BY STAR FORMATION RATES MEASURED FROM Hβ AND FUV
Authors: Guo Yicheng , Rafelski Marc , Faber S. M. , Koo David C. , Krumholz Mark R. , Trump Jonathan R. , Willner S. P. , Amorín Ricardo , Barro Guillermo , Bell Eric F. , Gardner Jonathan P. , Gawiser Eric , Hathi Nimish P. , Koekemoer Anton M. , Pacifici Camilla , Pérez-González Pablo G. , Ravindranath Swara , Reddy Naveen , Teplitz Harry I. , Yesuf Hassen 
Published: December 2016

ABSTRACT
We investigate the burstiness of star formation histories (SFHs) of galaxies at 0.4 < z < 1 by using the ratio of star formation rates (SFRs) measured from Hβ and FUV (1500 Å) (Hβ-to-FUV ratio). Our sample contains 164 galaxies down to stellar mass (M
*) of 108.5
M
⊙ in the CANDELS GOODS-N region, where Team Keck Redshift Survey Keck/DEIMOS spectroscopy and Hubble Space Telescope/WFC3 F275W images from CANDELS and Hubble Deep UV Legacy Survey are available. When the ratio of Hβ- and FUV-derived SFRs is measured, dust extinction correction is negligible (except for very dusty galaxies) with the Calzetti attenuation curve. The Hβ-to-FUV ratio of our sample increases with M
* and SFR. The median ratio is ∼0.7 at M
* ∼ 108.5
M
⊙ (or SFR ∼ 0.5 M
⊙ yr−1) and increases to ∼1 at M
* ∼ 1010
M
⊙ (or SFR ∼ 10 M
⊙ yr−1). At M
* < 109.5
M
⊙, our median Hβ-to-FUV ratio is lower than that of local galaxies at the same M
*, implying a redshift evolution. Bursty SFH on a timescale of a few tens of megayears on galactic scales provides a plausible explanation for our results, and the importance of the burstiness increases as M
* decreases. Due to sample selection effects, our Hβ-to-FUV ratio may be an upper limit of the true value of a complete sample, which strengthens our conclusions. Other models, e.g., non-universal initial mass function or stochastic star formation on star cluster scales, are unable to plausibly explain our results.
THE ASTEROID BELT AS A RELIC FROM A CHAOTIC EARLY SOLAR SYSTEM
Authors: Izidoro André , Raymond Sean N. , Pierens Arnaud , Morbidelli Alessandro , Winter Othon C. , Nesvorny` David 
Published: December 2016

ABSTRACT
The orbital structure of the asteroid belt holds a record of the solar system’s dynamical history. The current belt only contains ∼10−3 Earth masses yet the asteroids’ orbits are dynamically excited, with a large spread in eccentricity and inclination. In the context of models of terrestrial planet formation, the belt may have been excited by Jupiter’s orbital migration. The terrestrial planets can also be reproduced without invoking a migrating Jupiter; however, as it requires a severe mass deficit beyond Earth’s orbit, this model systematically under-excites the asteroid belt. Here we show that the orbits of the asteroids may have been excited to their current state if Jupiter’s and Saturn’s early orbits were chaotic. Stochastic variations in the gas giants’ orbits cause resonances to continually jump across the main belt and excite the asteroids’ orbits on a timescale of tens of millions of years. While hydrodynamical simulations show that the gas giants were likely in mean motion resonance at the end of the gaseous disk phase, small perturbations could have driven them into a chaotic but stable state. The gas giants’ current orbits were achieved later, during an instability in the outer solar system. Although it is well known that the present-day solar system exhibits chaotic behavior, our results suggest that the early solar system may also have been chaotic.
HIGH-RESOLUTION OBSERVATIONS OF MOLECULAR LINES IN ARP 220: KINEMATICS, MORPHOLOGY, AND LIMITS ON THE APPLICABILITY OF THE AMMONIA THERMOMETER
Authors: Zschaechner Laura K. , Ott Jürgen , Walter Fabian , Meier David S. , Momjian Emmanuel , Scoville Nick 
Published: December 2016

ABSTRACT
We observe Arp 220, the nearest ultra-luminous infrared galaxy, over 4 GHz in the K and Ka bands, providing constraints for the kinematics and morphology, and identifying molecular species on scales resolving both nuclei (0.″6 or 230 pc). We detect multiple molecular species, including hydroxyl (OH

) in both cores, and tentatively detect H2O(615-523) at ∼21.84 GHz in both nuclei, indicating the likely presence of maser emission. The observed frequency range also contains metastable ammonia transitions from (J, K) = (1, 1)–(5, 5), as well as the (9, 9) inversion line; together, they are a well-known thermometer of dense molecular gas. Furthermore, the non-metastable (4, 2) and (10, 9), and possibly the (3, 1), lines are also detected. We apply a standard temperature analysis to Arp 220; however, the analysis is complicated in that standard local thermal equilibrium (LTE) assumptions do not hold. There are indications that a substantial fraction of ammonia could be in the non-metastable transitions, as opposed to only the metastable ones. Thus, the non-metastable transitions could be essential to constraining the temperature. We compare all of these data to ALMA observations of this source, confirming the outflow previously observed by other tracers in both nuclei.
THE IMPRINT OF RADIAL MIGRATION ON THE VERTICAL STRUCTURE OF GALAXY DISKS
Authors: Vera-Ciro Carlos , D’Onghia Elena , Navarro Julio F. 
Published: December 2016

ABSTRACT
We use numerical simulations to examine the effects of radial migration on the vertical structure of galaxy disks. The simulations follow three exponential disks of different mass but similar circular velocity, radial scalelength, and (constant) scale height. The disks develop different non-axisymmetric patterns, ranging from feeble, long-lived multiple arms to strong, rapidly evolving few-armed spirals. These fluctuations induce radial migration through secular changes in the angular momentum of disk particles, mixing the disk radially and blurring pre-existing gradients. Migration primarily affects stars with small vertical excursions, regardless of spiral pattern. This “provenance bias” largely determines the vertical structure of migrating stars: inward migrators thin down as they move in, whereas outward migrators do not thicken up but rather preserve the disk scale height at their destination. Migrators of equal birth radius thus develop a strong scale-height gradient, not by flaring out as commonly assumed, but by thinning down as they spread inward. Similar gradients have been observed for low-[α/Fe] mono-abundance populations (MAPs) in the Galaxy, but our results argue against interpreting them as a consequence of radial migration. This is because outward migration does not lead to thickening, implying that the maximum scale height of any population should reflect its value at birth. In contrast, Galactic MAPs have scale heights that increase monotonically outward, reaching values that greatly exceed those at their presumed birth radii. Given the strong vertical bias affecting migration, a proper assessment of the importance of radial migration in the Galaxy should take carefully into account the strong radial dependence of the scale heights of the various stellar populations.
STATISTICAL TESTS OF GALACTIC DYNAMO THEORY
Authors: Chamandy Luke , Shukurov Anvar , Russ Taylor A. 
Published: December 2016

ABSTRACT
Mean-field galactic dynamo theory is the leading theory to explain the prevalence of regular magnetic fields in spiral galaxies, but its systematic comparison with observations is still incomplete and fragmentary. Here we compare predictions of mean-field dynamo models to observational data on magnetic pitch angle and the strength of the mean magnetic field. We demonstrate that a standard

dynamo model produces pitch angles of the regular magnetic fields of nearby galaxies that are reasonably consistent with available data. The dynamo estimates of the magnetic field strength are generally within a factor of a few of the observational values. Reasonable agreement between theoretical and observed pitch angles generally requires the turbulent correlation time τ to be in the range of 10–

, in agreement with standard estimates. Moreover, good agreement also requires that the ratio of the ionized gas scale height to root-mean-square turbulent velocity increases with radius. Our results thus widen the possibilities to constrain interstellar medium parameters using observations of magnetic fields. This work is a step toward systematic statistical tests of galactic dynamo theory. Such studies are becoming more and more feasible as larger data sets are acquired using current and up-and-coming instruments.
THE CRAB PULSAR AT CENTIMETER WAVELENGTHS. II. SINGLE PULSES
Authors: Hankins T. H. , Eilek J. A. , Jones G. 
Published: December 2016

ABSTRACT
We have carried out new, high-frequency, high-time-resolution observations of the Crab pulsar. Combining these with our previous data, we characterize bright single pulses associated with the Main Pulse, both the Low-Frequency and High-Frequency Interpulses, and the two High-Frequency Components. Our data include observations at frequencies ranging from 1 to 43 GHz with time resolutions down to a fraction of a nanosecond. We find that at least two types of emission physics are operating in this pulsar. Both Main Pulses and Low-Frequency Interpulses, up to ∼10 GHz, are characterized by nanoshot emission—overlapping clumps of narrowband nanoshots, each with its own polarization signature. High-Frequency Interpulses, between 5 and 30 GHz, are characterized by spectral band emission—linearly polarized emission containing ∼30 proportionately spaced spectral bands. We cannot say whether the longer-duration High-Frequency Components pulses are due to a scattering process, or if they come from yet another type of emission physics.
LABORATORY MEASUREMENTS COMPELLINGLY SUPPORT A CHARGE-EXCHANGE MECHANISM FOR THE “DARK MATTER” ∼3.5 keV X-Ray LINE
Authors: Shah Chintan , Dobrodey Stepan , Bernitt Sven , Steinbrügge René , López-Urrutia José R. Crespo , Gu Liyi , Kaastra Jelle 
Published: December 2016

ABSTRACT
The reported observations of an unidentified X-ray line feature at ∼3.5 keV have driven a lively discussion about its possible dark matter origin. Motivated by this, we have measured the K-shell X-ray spectra of highly ionized bare sulfur ions following charge exchange with gaseous molecules in an electron beam ion trap, as a source of or a contributor to this X-ray line. We produced S16+ and S15+ ions and let them capture electrons in collision with those molecules with the electron beam turned off while recording X-ray spectra. We observed a charge-exchange-induced X-ray feature at the Lyman series limit (3.47 ± 0.06 keV). The inferred X-ray energy is in full agreement with the reported astrophysical observations and supports the novel scenario proposed by Gu et al.