bluuebunny/crossref_metadata_2025 huggingface dataset:
PENGARUH MODEL PEMBELAJARAN BERBASIS MASALAH TERHADAP HASIL BELAJAR KOGNITIF MATEMATIKA SISWA MTs NEGERI 3 WAKATOBI DI BINONGKO
Authors: Lelastri Lelastri , Suhar Suhar , Ikman Ikman
Published: November 2019

Penelitian ini merupakan penelitian eksperimen. Populasi dalam penelitian ini adalah seluruh siswa kelas VIII MTs Negeri 3 Wakatobi di Binongko yang terdiri dari 3 kelas paralel berjumlah 59 siswa. Penentuan sampel dilakukan dengan teknik class random sampling. Sampel penelitian ini terdiri dari 39 siswa, yang terbagi atas dua kelompok  belajar, yaitu kelas VIII1 sebagai kelas eksperimen berjumlah 20 siswa dan kelas VIII2 sebagai kelas kontrol berjumlah 19 siswa. Data diperoleh menggunakan instrumen berupa tes hasil belajar kognitif matematika siswa. Teknik analisis data menggunakan statistik deskriptif dan statistik inferensial. Hasil penelitian secara deskriptif dan secara inferensial menunjukan bahwa: (1) Rata-rata hasil belajar kognitif matematika siswa yang pembelajaran menggunakan model pembelajaran berbasis masalah adalah 80,42; (2) Rata-rata hasil belajar kognitif matematika siswa yang pembelajaran menggunakan model pembelajaran konvensional adalah 70,03; (3) Pembelajaran dengan menggunakan model pembelajaran berbasis masalah memberikan pengaruh yang signifikan terhadap hasil belajar kognitif matematika siswa kelas VIII MTs Negeri 3 Wakatobi di Binongko.
PENGARUH PENDEKATAN REALISTIC MATHEMATICS EDUCATION (RME) TERHADAP KEMAMPUAN PEMAHAMAN MATEMATIS SISWA SMP NEGERI 11 KENDARI
Authors: Citra Sandri Yulia , Anggo Mustamin , Kadir Kadir
Published: November 2019

Penelitian ini dilatarbelakangi oleh rendahnya kemampuan pemahaman matematis siswa. Populasi dalam penelitian ini adalah seluruh siswa kelas VII SMP Negeri 11 Kendari yang tersebar di 4 kelas paralel dengan jumlah 101 siswa. Teknik pengambilan sampel dalam penelitian dilakukan secara purposive sampling. Teknik pengumpulan data dilakukan dengan pemberian tes kemampuan pemahaman berbentuk tes uraian. Berdasarkan hasil analisis data dan pembahasan diperoleh kesimpulan: (1) kemampuan pemahaman matematis siswa yang diajar dengan pendekatan Realistic Mathematics Education (RME) pada materi bentuk aljabar memiliki nilai minimum 62.50; nilai maksimum 91.67; nilai rata-rata 75.50; standar deviasi 8.45; varians 71.35; median 75.00 dan  modus 75.00, (2) kemampuan pemahaman matematis siswa yang diajar dengan pembelajaran konvesional pada materi bentuk aljabar memiliki nilai minimum 37.50; nilai maksimum 79.17; nilai rata-rata 62.00; standar deviasi 10.85; varians 117.65; median 62.50; serta  modus 62.50 dan 70.83, (3) terdapat  pengaruh yang signifikan pendekatan Realistic Mathematics Education (RME) terhadap kemampuan pemahaman matematis siswa.
PENGARUH PENDEKATAN CONTEXTUAL TEACHING AND LEARNING TERHADAP HASIL BELAJAR MATEMATIKA SISWA KELAS VIII SMP NEGERI 5 KENDARI
Authors: La Hasan La Hasan , Bey Anwar , Hasnawati Hasnawati
Published: November 2019

Penelitian ini bertujuan untuk mengetahui pengaruh pendekatan Contextual Teaching and Learning terhadap hasil belajar matematika siswa kelas VIII SMP Negeri 5 Kendari. Jenis penelitian ini yaitu eksperimen semu dengan rancangan posttest only control design. Populasinya adalah seluruh siswa kelas VIII SMP Negeri 5 Kendari berjumlah 362 siswa. Sampel diambil dengan teknik purpossive sampling, kelas kontrol dan kelas eksperimen ditentukan secara acak (random sampling). Kelas eksperimen (kelas VIII-G) berjumlah 36 siswa diajar dengan pendekatan Contextual Teaching and Learning dan kelas kontrol (kelas VIII-H) berjumlah 33 siswa diajar dengan pembelajaran konvensional. Instrumen penelitian terdiri dari lembar observasi dan tes hasil belajar. Data dikumpulkan dengan teknik observasi, dokumentasi, dan tes kemudian dianalisis dengan statistik deskriptif dan statistik inferensial. Hasilnya, rata-rata hasil belajar siswa kelas eksperimen (74,92) lebih tinggi daripada kelas kontrol (70,12). Kesimpulannya, pendekatan Contextual Teaching and Learning mempunyai pengaruh yang signifikan terhadap hasil belajar matematika siswa kelas VIII SMP Negeri 5 Kendari.
ANALISIS FAKTOR EKSTERNAL DAN INTERNAL TERHADAP KINERJA UMKM DI KOTA BATAM
Authors: Siagian Mauli , Kurniawan Putu Hari , Hikmah Hikmah
Published: November 2019

Sektor UMKM merupakan salahsatu sektor penting untuk sumber perekonomian masyarakat Indonesia. Hal ini selain karena usaha tersebut merupakan tulang punggung sistem ekonomi kerakyatan yang tidak hanya ditujukan untuk mengurangi masalah kesenjanganaantar golongan, pendapatan dan antar pelaku usaha, ataupun pengentasan kemiskinan dan penyerapan tenaga kerja. Dikota Batam kinerja sektor usaha mikro dan kecil (UMK) dipengaruhi oleh dua faktor utama yakni faktor-faktor eksternal dan faktor-faktor internal. Faktor internal meliputi aspek SDM (pemilik, manajer, dan karyawan), aspek keuangan, aspek teknis produksi; dan aspek pemasaran. Sedangkan Faktor eksternal terdiri dari kebijakan pemerintah, aspek sosial budaya dan ekonomi, serta peranan lembaga terkait seperti Pemerintah, Perguruan Tinggi, Swasta, dan LSM. Dalam penelitian ini bertujuan untuk mengetahui pengaruh eksternal dan internal terhadap kinerja usaha mikro, kecil dan menengah di Kota Batam. Populasi dalam penelitian ini adalah 2 kecamatan yang ada di Kota Batam yaitu Kecamatan Batu aji dan kecamatan Sagulung. Metode pengumpulan data mengunakan kuesioner. Sampel dalam penelitian ini 150 respoenden. Reseponden dalam penelitian ini adalah UMKM yang unit usahanya kuliner. Teknik penentuan sampel yang digunakan adalah purposive sampling. Adapun metode analisis yang digunakan mengunakan SEM dengan aplikasi SmartPLS. Hasil penelitian menunjukkan bahwa Faktor eksternal terdapat pengaruh terhadap faktor internal secara signifikan dan positif UMKM di Kota Batam; Faktor eksternal terdapat pengaruh terhadap Kinerja UMKM secara signifikan dan positif di Kota Batam; Faktor internal terdapat pengaruh terhadap Kinerja UMKM secara signifikan dan positif di Kota Batam.
Analisis Faktor-Fakror yang Mempengaruhi Keterikatan Karyawan pada Hotel Berbintang di Batam
Authors: Yuswardi Yuswardi
Published: November 2019

Penelitian ini bertujuan untuk mengetahui pengaruh dari variabel kepemimpinan, kepuasan kerja, lingkungan kerja, kompensasi dan pelatihan kerja terhadap keterikatan karyawan hotel berbintang yang ada di Batam. Penelitian ini perlu dilakukan untuk mendapatkan informasi mengenai faktor-faktor yang berpengaruh terhadap peningkatan keterikatan kerja karyawan hotel berbintang di Batam.

 

Penelitian ini dilakukan dengan metode survei melalui penyebaran kuesioner kepada 350 responden yang merupakan karyawan lima hotel berbintang yangmemiliki jumlah karyawan terbanyak di Batam. Setelah kuesioner disebarkan dan dikumpulkan kembali oleh penulis, berhasil didapatkan 350 kuesioner yang diisi dengan lengkap sehingga bisa dilakukan pengujian data regresi oleh penulis dengan menggunakan program SPSS. Dari hasil pengolahan data dengan SPSS diketahui bahwa terdapat hubungan pada hampir semua variabel yang diteliti.

 

Hasil penelitian ini menekankan tentang pentingnya bagi manajemen hotel berbintang untuk memberikan perhatian yang lebih besar pada variabel yang diteliti diatas. Karena hampir semua variabel tersebut diatas mempunyai hubungan erat dengan keterikatan karyawan, sehingga bila perusahaan ingin meningkatkan keterikatan karyawannya maka hal tersebut diatas harus ditingkatkan dan diperbaiki.

 

kepemimpinan, kepuasan kerja, lingkungan kerja, kompensasi dan pelatihan kerja, keterikatan karyawan dan hotel berbintang
Pengaruh Pertumbuhan Penjualan, Current Ratio, Debt to Equity Ratio terhadap Kinerja Keuangan PT.Sirma Pratama Nusa
Authors: Tasmil Levita Judini , Malau Novintan , Nasution Marwah
Published: November 2019

Penelitian ini dimaksudkan untuk menguji pengaruh Pertumbuhan Penjualan, Current Ratio dan Debt to Equity Ratio terhadap kinerja keuangan. Penelitian ini dilakukan di PT. Sirma Pratama Nusa dalam kurun waktu 2014-2017 dengan total populasi 48 bulan. Teknik pengambilan sample yang digunakan dalam penelitian ini adalah pengambilan sample jenuh dan diperoleh 48 bulan sampel. Hasil Dari penelitian ini adalah Current Ratio dan Debt to Equity Ratio mempengaruhi kinerja keuangan secara parsial dan pertumbuhan penjualan, Current Ratio dan Debt to Equity Ratio mempengaruhi kinerja keuangan secara simultan. Dengan diperkuat koefisien determinasi (R2) sebesar 0,988 yang menunjukkan bahwa 98,8% dari kinerja keuangan dapat dijelaskan oleh variabel pertumbuhan penjualan Current Ratio dan Debt to Equity ratio. Sedangkan sisanya 1,2% dipengaruhi oleh variabel lain diluar model yang diteliti.
Analisis Faktor-faktor yang Mempengaruhi Kinera Pegawai dalam Pegawai Organisasi Sektor Publik
Authors: Laoli Victorinus
Published: November 2019

The purpose of this research was examining the factors that affect the employee performance at the tax office in Gunungsitoli. The factors tested in this study were clear and measurable goals, incentives, motivation, remuneration, decentralization, and performance measurement systems for employee performance. This research was conducted by using questionnaires to all employees of Kantor Penyuluhan Dan Konsultasi  Perpajakan KP2KP Gunungsitoli. The data obtained was processed by using a regression that is part of the multiple regression. Number of questionnaires processed amounted to 40 questionnaires. The results of this study indicate that a clear and measurable goals, incentives, motivation,  remuneration,  decentralization  is  not  related  to  employee performance. While performance measurement system affect employee performance.
Pengaruh Times Interest Earned Ratio, Total Asset Turnover dan Perputaran Modal Kerja terhadap Profitabilitas pada Perusahaan Sub Sektor Property dan Real Estate yang terdaftar di Bursa Efek Indonesia periode 2013-2017
Authors: Yunita Yunita , Shelly Shelly , Ariani Novia , Chandra Erline , Selvia Selvia , Pane Afrizar , Putra Surya Kelana
Published: November 2019

This research was conducted with the aim of testing and analyzing how the influence of times interest earned ratio, total asset turnover and working capital turnover on profitability both simultaneously and partially in property and real estate companies listed on the Indonesia Stock Exchange in 2013-2017. The research method used in this study is a quantitative research approach, the type of research is associative or relationship and the nature of research is a causal relationship. The population in this study were all property and real estate companies listed on the Indonesia Stock Exchange in 2013-2017. Withdrawal of the study sample using purposive sampling technique, so that the research sample obtained as many as 90 observation observations. Data analysis method used in this study is the classic assumption test and multiple linear regression analysis with the SPSS program. The results of this study indicate that simultaneously times interest earned ratio, total asset turnover and working capital turnover have a significant effect on profitability. Partially, times interest earned ratio and total asset turnover have a significant effect on profitability while time working capital turnover has no effect on profitability. The test results of the coefficient of determination obtained by the value of R Square of 0.502, which means that the influence of times interest erned ratio, total asset turnover and working capital turnover on profitability in property and real estate companies listed on the Indonesia Stock Exchange in 2013-2017 is 50.2%, while the remaining 49.8% is influenced by other factors.
El interés superior del menor. Especial referencia al Sistema de Justicia Integral para Menores
Authors: Guillén López Germán
Published: November 2019

El presente artículo tiene como objetivo identificar el marco jurídico —internacional y nacional— en el que se pretende concretar el principio —o institución jurídica— que se conoce como Interés Superior del Menor. Después de revisar la citada normativa, se buscará una aproximación conceptual al precitado principio y se analizaran — mínimamente— los principales retos que implica su efectiva materialización en el ámbito jurídico.
SCIENTIFIC PRINCIPLES OF LABOUR PROTECTION EFFICIENCY INCREASING IN UKRAINE
Authors: Zdanovskyi V.
Published: November 2019

An in-depth analysis shows that the system of management of labor protection no longer meets the modern requirements of labor protection and requires reform. Improvement of the labor protection system in Ukraine includes the following aspects: economic factors of labor protection; harmonization of industrial relations in the system of employer-employee; risk-oriented approach to the estimation of production factors; a system for managing occupational safety requires a well-built and multi-faceted information network, necessary for decision-making; Implementation of the Concept of Reforming the system of labor protection management in Ukraine on the basis of modernization of legislative acts in the field of labor relations, including labor protection, taking into account world experience and almost thirty years of existence of an independent Ukrainian state.
Nephrogenic diabetes insipidus in a patient with lymphoma
Authors: Cristiana Rollino , Sandrone Manuela , Maria Pagliaro , Dario Roccatello
Published: November 2019

We present the case of a woman developing nephrogenic diabetes insipidus in the course of stage IVB T lymphoma with no involvement of the hypothalamus/pituitary area, but extensive involvement of both kidneys. A diagnosis of tubulopathy with acquired nephrogenic diabetes insipidus was made.
Consider cardiac and non-cardiac predictors of sudden death in myotonic dystrophy type 1
Authors: Finsterer Josef , Stöllberger Claudia
Published: November 2019

In an article from the New England Journal of Medicine Groh et al. [1], found severe electrocardiographic abnormalities (sECGA) to predict sudden death (SD) among 406 patients with myotonic dystrophy 1 (MD1). However, it remains unclear if data were retrospectively or prospectively collected, why QT-prolongation, ventricular ectopic beats, or runs were not assessed as sECGA, how heart failure was defined, why only a quarter of the patients underwent imaging-studies, and why cardiac imaging-studies were assessed as events [2,3].
A Treatise on the Surgical Management of Porcelain Atrium and Coconut Atrium
Authors: Chowdhury Ujjwal K. , Sankhyan Lakshmi Kumari , Gudala Vasubabu , Singh Sukhjeet , George Niwin , Chowdhury Priyanka , Chowdhury Sreenita , Malik Vishwas
Published: November 2019

The present perspective is a synthesis of 119 published investigations in the setting of porcelain atrium and coconut atrium in the literature. We identified 60 suitable cases (porcelain atrium, n=44; coconut atrium, n=16) from 34 investigations, and reviewed the clinical presentation, diagnostic modalities utilized, surgical techniques employed and outcomes. Roentgenography, cross-sectional transthoracic and transesophageal echocardiography, computerized tomography and fluoroscopy provided the necessary diagnostic information and defined the disease entity before surgery in all patients. Magnetic resonance imaging and selective coronary angiography had been used for further clarification of the presence of intraluminal left atrial thrombus. We then grouped the lesions into two categories, namely “porcelain atrium” and “coconut atrium” that have a bearing on the appropriate surgical approach, discussing appropriate surgical or non-surgical techniques for each group. For the overall group, taking into consideration of the patients subjected to surgical intervention, the operative mortality remains high at 20.6% [porcelain atrium: hospital death 6/30 (20%), coconut atrium: hospital death 1/4 (25%). We submit that an increased appreciation of different types of left atrial wall calcification may well contribute to improved surgical management.
Catharsis as a therapy: an overview on health and human development
Authors: Bukar Aisha , Abdullah Abdulsalam , Opara Jacinta A , M Abdulkadir , Hassan Abdulazeez
Published: November 2019

The word catharsis is derived from the Greek word which is translated as cleansing or purification. Most of the definitions emphasize two essential components of catharsis: the emotional aspect (strong emotional expression and processing) and the cognitive aspect of catharsis (insight, new realization, and the unconscious becoming consciousness) and as a result - positive change. Aristotle defined catharsis as purging of the spirit of morbid and base ideas or emotions by witnessing the playing out of such emotions or ideas on stage [1]. Breuer and Freud described catharsis as an involuntary, instinctive body process, for example crying [2]. Schultz and Schultz (2004) followed the psychodynamic tradition and defined catharsis as the process of reducing or eliminating a complex by recalling it to conscious awareness and allowing it to be expressed [3]. The American Psychological Association [4] also associates catharsis with the psychodynamic theory and defines it as the discharge of affects connected to traumatic events that had previously been repressed by bringing these events back into consciousness and reexperiencing them.
Correlates of psychiatric and psychological distress in patients with Parkinson’s disease
Authors: van Oers Helena M
Published: November 2019

Parkinson’s disease is the second most commonly diagnosed neurodegenerative disorder worldwide and the physical manifestations of the disease are well documented in the literature. However, in excess of 60% of patients with the disease report having one or more psychiatric symptoms which worsen as the disease progresses. These symptoms arise differentially from the same pathology which underlies the disease or from the treatment with dopaminergic drugs. Psychiatric and psychological difficulties tend to be under-recognised and undertreated yet cause great disability, significantly impact the quality of life of patients and add to greater burden on their caregivers. These symptoms can be relieved through adjusting the doses of anti-Parkinson’s drug therapy and success in improving psychological distress has been found using adjuvant psychotherapeutic intervention, most notably with Cognitive Behavioural Therapy.
Who is Riding to the South African Bike Festival?
Authors: Borstlap Hanneri , Fourie Alicia
Published: November 2019

Events play an integrated part in tourism industry. South Africa events have grown over the past years, especially when it comes to promotion and hosting of events. One such event is South African Bike Festival. The event's organizers host these events for special causes, such as riding
for a purpose, social implications, and social responsibility. Motorcycles have been around since the early 1900s for the dual purpose of transportation and recreational or pleasure riding, but little is known about motorcyclists' sociodemographic profile and behavior. From an international
perfective, the sociodemographic and behavior aspects of motorcyclists are well documented; what is lacking is literature within the South African perceptive. The purpose of this research is to characterize those who attended the first South African Bike Festival. The research attempts to
segment the motorcycle market and identify bikers' motivations, needs, and behavior. A structured self-completion questionnaire was developed and handed out to willing participants. Trained fieldworkers distributed the questionnaire over a 3-day period and received a total of 484 usable questionnaires.
A multiple regression based on sociodemographic variables and spending habits was done to determine any significant differences. Respondents were segmented based on their motives for attending the event. In this way three markets were identified, namely hardcore biker, feisty biker,
and fortuitous biker. The results showed that there are indeed significant differences between the three markets identified. This research not only contributes to the motorcycling literature, but also to motorcycling behavior of bikers in South Africa.
Resurrecting the genus Geomorium: Systematic study of fungi in the genera Underwoodia and Gymnohydnotrya (Pezizales) with the description of three new South American species
Authors: Kraisitudomsook N. , Healy R.A. , Pfister D.H. , Truong C. , Nouhra E. , Kuhar F. , Mujic A.B. , Trappe J.M. , Smith M.E.
Published: November 2019

Molecular phylogenetic analyses have addressed the systematic position of several major Northern Hemisphere lineages of Pezizales but the taxa of the Southern Hemisphere remain understudied. This study focuses on the molecular systematics and taxonomy of Southern Hemisphere species
currently treated in the genera Underwoodia and Gymnohydnotrya. Species in these genera have been identified as the monophyletic/gymnohydnotrya lineage, but no further research has been conducted to determine the evolutionary origin of this lineage or its relationship with other
Pezizales lineages. Here, we present a phylogenetic study of fungal species previously described in Underwoodia and Gymnohydnotrya, with sampling of all but one described species. We revise the taxonomy of this lineage and describe three new species from the Patagonian
region of South America. Our results show that none of these Southern Hemisphere species are closely related to Underwoodia columnaris, the type species of the genus Underwoodia. Accordingly, we recognize the genus Geomorium described by Spegazzini in 1922 for G. fuegianum.
We propose the new family, Geomoriaceae fam. nov., to accommodate this phylogenetically and morphologically unique Southern Hemisphere lineage. Molecular dating estimated that Geomoriaceae started to diverge from its sister clade Tuberaceae c. 112 MYA, with a crown age
for the family in the late Cretaceous (c. 67 MYA). This scenario fits well with a Gondwanan origin of the family before the split of Australia and South America from Antarctica during the Paleocene-Eocene boundary (c. 50 MYA).
Search for the H Chondrite Parent Body among the Three Largest S-type Asteroids: (3) Juno, (7) Iris, and (25) Phocaea
Authors: Noonan John W. , Reddy Vishnu , Harris Walter M. , Bottke William F. , Sanchez Juan A. , Furfaro Roberto , Brown Zarah , Fernandes Rachel , Kareta Theodore , Lejoly Cassandra , Nallapu Ravi Teja , Niazi Haris Khan , Slick Lindsay R. , Schatz Lauren , Sharkey Benjamin N. L. , Springmann Alessondra , Angle Geoff , Bailey Leandra , Acuna Derian D. , Lewin Collin , Marchese Katherina , Meshel Max , Quintero Natalie , Tatum Kyle , Wilburn Greg
Published: November 2019

Linking meteorites to source regions in the main asteroid belt is important for understanding the conditions under which their parent bodies formed. Ordinary chondrites are the most abundant class of meteorites on Earth, totaling 86% of all collected samples. Some S-type asteroids/families have been proposed as sources for the three different (H, L, and LL) types of ordinary chondrites with Hebe, Agnia, Merxia, and Koronis families being the source for H chondrites, Gefion for H/L chondrites, and Flora family for LL chondrites. However, the composition and meteorite affinity of several large S-type main belt asteroids remains unconstrained leaving the possibility of additional source regions for ordinary chondrite meteorites. Here we investigate the surface composition of three large S-type asteroids, (3) Juno, (7) Iris, and (25) Phocaea, using their near-infrared spectra (0.7–2.55 μm) to identify the parent body of the H chondrites. We use a Bayesian inference model to confirm the meteorite analogs of the three asteroids. Based on our Bayes classifier we find the following analogs and probabilities: Juno is likely H chondrite (89%), Iris is likely LL chondrite (97.5%), and Phocaea is likely H chondrite (98.6%). While Phocaea has the highest probability of being an H chondrite, it is dynamically unlikely to deliver material to near-Earth space. While Juno has spectral properties similar to H chondrites, its family is unlikely to produce sizeable H-chondrite-type near-Earth objects (NEOs). If Juno is the primary source of H chondrite meteorites, it suggests that an additional source is needed to explain the H-chondrite-type NEOs.
Mind the Gap: Is the Too Big to Fail Problem Resolved?
Authors: Ostriker Jeremiah P. , Choi Ena , Chow Anthony , Guha Kundan
Published: November 2019

The faintness of satellite systems in galaxy groups has contributed to the widely discussed “missing satellite” and “too big to fail” issues. Using techniques based on Tremaine & Richstone, we show that there is no problem with the luminosity function computed from modern codes per se, but that the gap between first and second-brightest systems is too big given the luminosity function, and the same large gap found in modern, large-scale baryonic ΛCDM simulations such as EAGLE and IllustrisTNG, is even greater in dark-matter-only simulations. Additionally, this is most likely due to gravitationally induced merging caused by classical dynamical friction. Quantitatively, the gap is larger in the computed simulations than in the randomized ones by 1.79 ± 1.04, 1.51 ± 0.93, 3.43 ± 1.44, and 3.33 ± 1.35 mag in the EAGLE, IllustrisTNG, and dark-matter-only simulations of EAGLE and IllustrisTNG, respectively. Furthermore, the anomalous gaps in the simulated systems are even larger than those in the real data by over half a magnitude and are still larger in the dark-matter-only simulations. Briefly stated, ΛCDM does not have a problem with an absence of “too big to fail” galaxies. Statistically significant large gaps between first and second-brightest galaxies are to be expected.
2 mm GISMO Observations of the Galactic Center. I. Dust Emission*
Authors: Arendt Richard G. , Staguhn Johannes , Dwek Eli , Morris Mark R. , Yusef-Zadeh Farhad , Benford Dominic J. , Kovács Attila , Gonzalez-Quiles Junellie
Published: November 2019

The central molecular zone, covering the inner ∼1° of the Galactic plane has been mapped at 2 mm using the Goddard-IRAM Superconducting 2-Millimeter Observer (GISMO) bolometric camera on the 30 m IRAM telescope. The 21″ resolution maps show abundant emission from cold molecular clouds, from star-forming regions, and from one of the Galactic center nonthermal filaments. In this work we use the Herschel Hi-GAL data to model the dust emission across the Galactic center. We find that a single-temperature fit can describe the 160–500 μm emission for most lines of sight, if the long-wavelength dust emissivity scales as λ
−β
with β ≈ 2.25. This dust model is extrapolated to predict the 2 mm dust emission. Subtraction of the model from the GISMO data provides a clearer look at the 2 mm emission of star-forming regions and the brightest nonthermal filament.
Simulated Interactions between Radio Galaxies and Cluster Shocks. II. Jet Axes Orthogonal to Shock Normals
Authors: Nolting Chris , Jones T. W. , O’Neill Brian J. , Mendygral P. J.
Published: November 2019

We report a 3D MHD simulation study of the interactions between radio galaxies (RGs) and galaxy-cluster-media shocks in which the incident shock normals are orthogonal to the bipolar active galactic nucleus (AGN) jets. Before shock impact, light, supersonic jets inflate lobes (cavities) in a static, uniform intracluster medium. We examine three AGN activity scenarios: (1) continued, steady jet activity; (2) jet source cycled off coincident with shock/radio lobe impact; (3) jet activity ceased well before shock arrival (a “radio phoenix” scenario). The simulations follow relativistic electrons (CRe) introduced by the jets, enabling synthetic radio synchrotron images and spectra. Such encounters can be decomposed into an abrupt shock transition and a subsequent long-term postshock wind. Shock impact disrupts the preformed, low-density RG cavities into two ring vortices embedded in the postshock wind. Dynamical processes cause the vortex pair to merge as they propagate downwind somewhat faster than the wind itself. When the AGN jets remain active, ram pressure bends the jets downwind, generating a narrow angle tail morphology aligned with the axis of the vortex ring. The deflected jets do not significantly alter dynamical evolution of the vortex ring. However, active jets and their associated tails do dominate the synchrotron emission, compromising the observability of the vortex structures. Downwind-directed momentum concentrated by the jets impacts and alters the postencounter shock. In the “radio phoenix” scenario, no DSA of the fossil electron population is required to account for the observed brightening and flattening of the spectra; adiabatic compression effects are sufficient.
Finding the Critical Decay Index in Solar Prominence Eruptions
Authors: Vasantharaju N. , Vemareddy P. , Ravindra B. , Doddamani V. H.
Published: November 2019

The background field is assumed to play a prime role in erupting structures like prominences. In the flux rope models, the critical decay index (n

c
) is a measure of the rate at which background field intensity decreases with height over the flux rope or erupting structure. In the real observations, the critical height of the background field is unknown, so a typical value of n

c
 = 1.5 is adopted from numerical studies. In this study, we determined the n

c
of 10 prominence eruptions (PEs). The prominence height in 3D is derived from two-perspective observations of the Solar Dynamics Observatory and the Solar TErrestrial RElations Observatory. Synoptic maps of photospheric radial magnetic field are used to construct the background field in the corona. During the eruption, the height–time curve of the sample events exhibits the slow- and fast-rise phases and is fitted with the linear-cum-exponential model. From this model, the onset height of fast-rise motion is determined and is considered as the critical height for the onset of the torus instability because the erupting structure is allowed to expand exponentially provided there is no strapping background field. Corresponding to the critical height, the n

c
values of our sample events are varied to be in the range of 0.8–1.3. Additionally, the kinematic analysis suggests that the acceleration of PEs associated with flares are significantly enhanced compared to flareless PEs. We found that the flare magnetic reconnection is a more dominant contributor than the torus instability to the acceleration process during the fast-rise phase of flare-associated PEs in low corona (<1.3R
⊙).
Hβ and Hγ Absorption-line Profile Inconsistencies in Laboratory Experiments Performed at White Dwarf Photosphere Conditions
Authors: Schaeuble M.-A. , Nagayama T. , Bailey J. E. , Gomez T. A. , Montgomery M. H. , Winget D. E.
Published: November 2019

The spectroscopic method relies on hydrogen Balmer absorption lines to infer white dwarf (WD) masses. These masses depend on the choice of atmosphere model, hydrogen atomic line shape calculation, and which Balmer series members are included in the spectral fit. In addition to those variables, spectroscopic masses disagree with those derived using other methods. Here we present laboratory experiments aimed at investigating the main component of the spectroscopic method: hydrogen line shape calculations. These experiments use X-rays from Sandia National Laboratories’ Z-machine to create a uniform ∼15 cm3 hydrogen plasma and a ∼4 eV backlighter that enables recording high-quality absorption spectra. The large plasma, volumetric X-ray heating that fosters plasma uniformity, and the ability to collect absorption spectra at WD photosphere conditions are improvements over past laboratory experiments. Analysis of the experimental absorption spectra reveals that electron density (

) values derived from the Hγ line are ∼34% ± 7.3% lower than from Hβ. Two potential systematic errors that may contribute to this difference were investigated. A detailed evaluation of self-emission and plasma gradients shows that these phenomena are unlikely to produce any measurable Hβ–Hγ

difference. WD masses inferred with the spectroscopic method are proportional to the photosphere density. Hence, the measured Hβ–Hγ

difference is qualitatively consistent with the trend that WD masses inferred from their Hβ line are higher than that resulting from the analysis of Hβ and Hγ. This evidence may suggest that current hydrogen line shape calculations are not sufficiently accurate to capture the intricacies of the Balmer series.
The 2MASS Redshift Survey in the Zone of Avoidance
Authors: Macri Lucas M. , Kraan-Korteweg Renée C. , Lambert Trystan , Alonso María Victoria , Berlind Perry , Calkins Michael , Erdoğdu Pirin , Falco Emilio E. , Jarrett Thomas H. , Mink Jessica D.
Published: November 2019

The Two Micron All-Sky Survey (2MASS) Redshift Survey was started two decades ago with the goal of mapping the three-dimensional distribution of an all-sky flux-limited (K

s
< 11.75 mag) sample of ∼45,000 galaxies. Our first data release presented an unprecedented uniform coverage for most of the celestial sphere, with redshifts for ∼98% of our sample. However, we were missing redshifts for ∼18% of the catalog entries that were located within the “Zone of Avoidance” (

)—an important region of the sky for studies of the large-scale structure and cosmic flows. In this second and final data release, we present redshifts for all 1041 2MRS galaxies that previously lacked this information, as well as updated measurements for 27 others.
Thitarodes shambalaensis sp. nov. (Lepidoptera, Hepialidae): a new host of the caterpillar fungus Ophiocordyceps sinensis supported by genome-wide SNP data
Authors: Wang Zhengyang , Zhuang Hailing , Wang Min , Pierce Naomi E.
Published: November 2019

A new species of ghost moth,Thitarodes shambalaensissp. nov., is described from Yanzigou glacier, Mt. Gongga, Sichuan, China. The species is a host of the economically important caterpillar fungusOphiocordyceps sinensis. Establishment of this new species is supported by morphology and genetic differentiation measured in a CO1 phylogeny and in genome-wide SNP coverage. A summary tree from 538 sequences of different genetic markers fromThitarodes(including sequences extracted from caterpillar fungus sclerotium samples) support the genusThitarodesas a monophyletic group, and indicate thatThitarodesis the host genus forO. sinensis. Sampling efforts so far have centered on half of the known phylogenetic diversity ofThitarodes, with some species-level clusters (separated by < 2.5% genetic distance) containing 17 described species. Fifteen clusters are known from either a single “orphan taxon” or a single sequence from a caterpillar fungus sclerotium sample. We provide suggestions for building a more robust phylogeny of the genusThitarodesand highlight some of the conservation threats that species from this genus face due to unprecedented habitat exploitation.
Remarkable confusion in some Western Palearctic Clepsis leads to a revised taxonomic concept (Lepidoptera, Tortricidae)
Authors: Zlatkov Boyan , Huemer Peter
Published: November 2019

The taxonomy of some Palearctic species of the genusClepsisGuenée, 1845 (Lepidoptera, Tortricidae), in particularC. neglectanasensu auctt. andC. consimilanasensu auctt., is revised based on combined characters of external and internal adult morphology, including everted vesicae in male genitalia, and DNA barcodes.Clepsis striolana(Ragonot, 1879),stat. rev.,C. acclivana(Zerny, 1933),C. trivia(Meyrick, 1913),stat rev., andC. xylotoma(Meyrick, 1891),stat. rev.are resurrected from synonymy withC. neglectana(Herrich-Schäffer, 1851),C. semiana(Chrétien, 1915),stat. nov.is considered as a valid species;C. eatoniana(Ragonot, 1881),stat. rev., is resurrected from synonymy withC. consimilana(Hübner, 1817), andC. razowskiiGastón, Vives & Revilla, 2017,syn. nov.is synonymised withC. eatoniana.
Notes on the sinistral helicoid snail Bertia cambojiensis (Reeve, 1860) from Vietnam (Eupulmonata, Dyakiidae)
Authors: Sutcharit Chirasak , Naggs Fred , Ablett Jonathan , Sang Pham Van , Hao Luong Van , Panha Somsak
Published: November 2019

Since the time of the original description there have been no precise locality records in Cambodia ofBertia cambojiensis(Reeve, 1860) and it was believed to be extinct. In 2012, a joint Natural History Museum survey with Vietnamese colleagues rediscovered living populations of this huge sinistral helicoid snail in a protected area of southern Vietnam. The genitalia and radula morphology are re-assessed and type specimens of all recognised congeners are figured herein. The unique morphological characters of this species are a small and simple penis, well-developed amatorial organ complex that incorporates four amatorial organ ducts, a short gametolytic organ complex and spiked papilla, and radula morphology with unicuspid teeth. The type locality ofB. cambojiensis, which has been contentious, is determined here to be in the vicinity of ‘Brelum’, Vietnam, near the border with Cambodia. In addition, the nucleotide sequences of barcoding genes COI, 16SrRNA and 28S fragments were provided for further comparison.
Taxonomic revision of Megalothoraca (Diptera: Richardiidae) with description of a new species, synonyms and new combination
Authors: Dilli Wendt Lisiane , Marinoni Luciane
Published: November 2019

A taxonomic revision of Megalothoracha Hendel, 1911 is provided, including a description of Megalothoraca rosalyae Wendt, sp. nov. from Colombia. The genus encompasses large species from Colombia, Ecuador, Peru and Bolivia (new record), and each species was described based either on males or females. These species can be diagnosed by long and slender mid and hind legs and wing longer than body, vein R2+3 with two strong curves on apical third, and short spurious vein medially. And males have costal vein conspicuously bowed anteriorly and thickened on medial portion. The following nomenclatural changes are made: Megalothoraca hendeli Enderlein, 1912, syn. nov. is a junior synonym of M. pterodontida Hendel, 1911; Batrachophthalmum teleopsis (Hennig, 1938) comb. nov. is transferred from Megalothoraca, and Batrachophthalmum quimbaya Carvalho, Wolff & Wendt, 2011, syn. nov. is a junior synonym of B. teleopsis. A key to species and illustrations of the female and male terminalia are provided.
Clean Energy, its Prospect and Challenges in India: A Literature Review
Authors: Borthakur Abhilash , Bora Tushar Ranjan , Nath Thuleswar , Bakul Barua Parimal
Published: November 2019

The survey primarily deals with the evaluation of green technology development in India. With the depletion of fossil fuels resources, increase of supply security issues, and menace of climate change; clean energy through green technology may offer the best possibilities and outlook for their long-term replacement. The United Nations designated the decade 2014–2024 as the “Decade of Sustainable Energy for All”. Achieving feasibility in energy employment is expected to create a cleaner environment, broader access to electricity, better energy efficiency, and result in greater investment in green technology. Clean energy initiative is not only to substitute the conventional source of energy, but for protecting the mother earth for the future mankind. Emblematic lantern and the oil lamp were the most prominent sources of light at nights for Indians when it achieved independence as it was suffering from severe electricity deficit. However scenario has changed after six decades. As per census 2011, out of 191.9 million household 107.2 million households were electrified. India is, however, aiming high in this domain, with a target to attain 175 GW of installed renewables capacity by 2022 which include 100 GW of solar, 60 GW of wind, 10 GW of bio power and 5 GW of small hydro-power. This survey has taken up to trace the research trends in India to fulfill the mission to almost substitute the conventional energy.
Contact Stress and Fatigue Analysis of Spur Gear
Authors: Hanoca Hanoca , Sharath P.C. , Ramakrishna H.V.
Published: November 2019

Spur gear is the most basic type of parallel-axis gear. In this study, contact stress and fatigue life of spur gear for different modules and for different materials were studied. The commercially available Solidworks 2016 is used for modelling and ANSYS Workbench tool for discretizing and solving. The analysis has been performed on the gear models of modules 1mm, 2mm and 3mm to observe the distribution of contact stress and life. The graphic results obtained were compared and it was found that contact stress decreases as the module increases and also aluminium alloy was having the least stress and high fatigue life among the selected materials. Hence from the finite element analysis, it’s found that the contact stress depends on the module and material used. Similarly fatigue life of gear purely depends on the material chosen.
Role of Zirconia Filler on Mechanical Properties of HDPE/UHMWPE Blend Composites
Authors: Suresha Bheemappa , Padaki Achyutananta , Jain Akash , Kumar Bharath , Kulkarni Akshay A.
Published: November 2019

Hybrid composites based on high-density polyethylene-grafted maleic anhydride /ultra-high density HYPERLINK "https://www.sciencedirect.com/topics/materials-science/polypropylene" \o "Learn more about Polypropylene" polyethylene (HDPE/UHMWPE) loaded with short glass fiber (SGF) and zirconia (ZrO2) micron sized particles were fabricated by melt-mixing process and their physical and mechanical properties were determined. Physio-mechanical properties such as density, hardness, flexural properties and impact strength of these composites were studied. The presence of SGF and ZrO2 in the grafted HDPE/UHMWPE blend increased the hardness, bending strength and modulus. However, impact strength decreased with increase in ZrO2 loading. Further, it was found that the HDPE/UHMWPE blend with 25 wt. % SGF and 2.5 wt. %ZrO2 showed optimum mechanical properties due to improved fiber/matrix adhesion. Scanning electron microscope was used to identify the fractographic features of the selected fractured coupons.
Analytical and Finite Element Solution of Tractor Brake Link to Achieve Weight and Cost Reduction
Authors: Krishna Anantha G.L. , Kumar K.M. Sathish
Published: November 2019

In tractor brakes, when the brake is applied, tension in the operating rod causes the links to turn the two actuating disc slightly, in opposite directions. The shape of the recesses in which the hardened steel balls locate is such that, as disc move relative to each other, the ball force them apart and apply pressure to the rotating discs. The automotive industry has for many years identified weight reduction as a way of improving product competitiveness and thus the ability to make profits. In present work, an attempt has been made to reduce the thickness of link and hence achieve weight reduction and cost savings. The actuator link has been analyzed for stresses. The existing link is of 6 mm thickness and is made of C – 40 steel. The existing link of 6 mm thickness along with links of 5 mm and 4 mm thickness were considered for analysis. It is found that the stresses in 5 mm thick link are well within limits with a factor of safety of 2.3. This reduction in thickness would yield a reduction in weight of link and hence would reduce the cost of link with a saving potential of Rs.14, 40000/= per year considering the fact that 6, 00,000 tractors are sold in India every year. Experimental investigation showed the zone of failure of link is in line with the high stress zone indicated by finite element analysis.
Machining Capabilities of Abrasive Waterjet on Stainless Steel 304
Authors: Supriya S.B. , Srinivas S.
Published: November 2019

Stainless Steels are possessing fabrication flexibility, high hardness, durability, low maintenance, high strength and resistance to heat and corrosion. This alloy steel is extensively used in various engineering applications. Some of the conventional machining techniques results in loss of original properties of stainless steel work material and makes it to behave like ordinary material within the machined surface. Machining of Stainless steels is more challenging due to its high alloying content. Problems such as application of huge coolant supply and poor chip breaking while machining, work hardening in work material, use of cutting tools with varying tool signature, results in enhanced production cost and time. Further, it is important to ensure that there is no machine tool-cutting tool vibration leading to edge chipping of cutting tool. To avoid all these problems, Abrasive water jet machining (AWJM) is used. This paper presents the machining capabilities of AWJ on Stainless Steel304. Influence of dynamic input parameters such as jet pressure, speed of traverse and abrasive flow rate on the depth of cut is investigated. An empirical model is proposed for depth of cut and an error analysis is done with measured and modeled values of depth of cut. It was found that traverse speed influences more than other parameters. SEM images indicated smooth surface at entrance and waviness at exit side. The model proposed predicts the depth of cut more or less accurately.
Tribological Properties of Calotropis Procera Natural Fiber Reinforced Hybrid Epoxy Composites
Authors: Raghu M.J. , Goud Govardhan
Published: November 2019

Natural fibers are widely used for reinforcement in polymer composite materials and proved to be effectively replacing synthetic fiber reinforced polymer composites to some extent in applications like domestic, automotive and lower end aerospace parts. The natural fiber reinforced composites are environment friendly, have high strength to weight ratio as well as specific strengths comparable with synthetic glass fiber reinforced composites. In the present work, hybrid epoxy composites were fabricated using calotropis procera and glass fibers as reinforcement by hand lay-up method. The fibre reinforcement in epoxy matrix was maintained at 20 wt%. In 20 wt% reinforcement of fibre, the content of calotropis procera and glass fibre were varied from 5, 10, 15 and 20 wt%. The dry sliding wear test as per ASTM G99 and three body abrasive wear test as per ASTM G65 were conducted to find the tribological properties by varying speed, load, distance and abrasive size. The hybrid composite having 5 wt% calotropis procera and 15 wt% glass fibre showed less wear loss in hybrid composites both in sliding wear test as well as in abrasive wear test which is comparable with 20 wt% glass fibre reinforced epoxy composite which marked very low wear loss. The SEM analysis was carried out to study the worn out surfaces of dry sliding wear test and three body abrasive wear test specimens.
Hybrid Non Conventional Machining of Glass - A Review
Authors: Nagaraj Y. , Jagannatha N. , Sathisha N.
Published: November 2019

Glass, being considered as hard and brittle material is very difficult to machine into desired shapes. The readily available conventional machining process does not provide good surface finish thus requires additional machining process. This paper reviews the different existing non conventional machining process accessible till today for the machining of glass materials. This paper also discusses the advantages and disadvantages of the existing non conventional machining processes. The various hybrid non conventional machining processes are also studied with focus on machining output characteristics like MRR, surface finish, tool wear rate. This paper summarizes the selection of hybrid non conventional machining processes for the various type of glass.