Students' epistemological framing in quantum mechanics problem solving

Students' difficulties in quantum mechanics may be the result of unproductive framing and not a fundamental inability to solve the problems or misconceptions about physics content. We observed groups of students solving quantum mechanics problems in an upper-division physics course. Using the lens of epistemological framing, we investigated four frames in our observational data: algorithmic math, conceptual math, algorithmic physics, and conceptual physics. We discuss the characteristics of each frame as well as causes for transitions between different frames, arguing that productive problem solving may occur in any frame as long as students' transition appropriately between frames. Our work extends epistemological framing theory on how students frame discussions in upper-division physics courses.Comment: Submitted to Physical Review -- Physics Education Researc

Multiple phase transitions in an agent-based evolutionary model with neutral fitness

Null models are crucial for understanding evolutionary processes such as speciation and adaptive radiation. We analyse an agent-based null model, considering a case without selection—neutral evolution—in which organisms are defined only by phenotype. Universal dynamics has previously been demonstrated in a related model on a neutral fitness landscape, showing that this system belongs to the directed percolation (DP) universality class. The traditional null condition of neutral fitness (where fitness is defined as the number of offspring each organism produces) is extended here to include equal probability of death among organisms. We identify two types of phase transition: (i) a non-equilibrium DP transition through generational time (i.e. survival), and (ii) an equilibrium ordinary percolation transition through the phenotype space (based on links between mating organisms). Owing to the dynamical rules of the DP reaction–diffusion process, organisms can only sparsely fill the phenotype space, resulting in significant phenotypic diversity within a cluster of mating organisms. This highlights the necessity of understanding hierarchical evolutionary relationships, rather than merely developing taxonomies based on phenotypic similarity, in order to develop models that can explain phylogenetic patterns found in the fossil record or to make hypotheses for the incomplete fossil record of deep time

Analisis Kinerja Guru yang Merangkap sebagai Pengelola Perpustakaan ( Studi Kasus di SMA Negeri 1, 5, 7, dan 8 di Lingkungan Surakarta )

Pengelola Perpustakaan di SMA Negeri 1, 5, 7, dan 8 Surakarta yang mendapat tugas tambahan untuk mengelola perpustakaan sekolah masing-masing. Penelitian dilakukan di Perpustakaan Sekolah SMA Negeri 1, 5, 7, dan 8 di lingkungan Surakarta dengan menggunakan metode kualitatif. Pengumpulan data dilakukan dengan wawancara. Jumlah informannya sebanyak 5 orang, yang terpilih dengan menggunakan teknik pengambilan sampel Purposive Sampling. Hasil yang diperoleh dari penelitian ini bahwa para guru pustakawan di SMA Negeri 1, 5, 7, dan 8 Surakarta merasa terganggu ketika menjalani profesinya sebagai guru dan pengelola perpustakaan. Namun begitu pelaksanaan tugas sebagai guru yang merangkap sebagai pengelola perpustakaan perlu adanya manajemen sumber daya manusia, sehingga dalam menjalankan tugas tidak saling mengganggu satu sama lain, antara lain: pembagian jadwal mengajar dan mengelola perpustakaan

A self-driven phase transition drives Myxococcus xanthus fruiting body formation

Combining high-resolution single cell tracking experiments with numerical simulations, we show that starvation-induced fruiting body (FB) formation in Myxococcus xanthus is a phase separation driven by cells that tune their motility over time. The phase separation can be understood in terms of cell density and a dimensionless Peclet number that captures cell motility through speed and reversal frequency. Our work suggests that M. xanthus take advantage of a self-driven non-equilibrium phase transition that can be controlled at the single cell level

Measurement Invariance of the Internet Addiction Test Among Hong Kong, Japanese, and Malaysian Adolescents

There has been increased research examining the psychometric properties on the Internet Addiction Test across different ages and populations. This population-based study examined the psychometric properties using Confirmatory Factory Analysis and measurement invariance using Item Response Theory (IRT) of the IAT in adolescents from three Asian countries. In the Asian Adolescent Risk Behavior Survey (AARBS), 2,535 secondary school students (55.91% girls) in Grade 7 to Grade 13 (Mean age = 15.61 years; SD=1.56) from Hong Kong (n=844), Japan (n=744), and Malaysia (n=947) completed a survey on their Internet use that incorporated the IAT scale. A nested hierarchy of hypotheses concerning IAT cross-country invariance was tested using multi-group confirmatory factor analysis. Replicating past finding in Hong Kong adolescents, the construct of IAT is best represented by a second-order three-factor structure in Malaysian and Japanese adolescents. Configural, metric, scalar, and partial strict factorial invariance was established across the three samples. No cross-country differences on Internet addiction were detected at latent mean level. This study provided empirical support to the IAT as a reliable and factorially stable instrument, and valid to be used across Asian adolescent populations

Pola Makan dan Pola Pencarian Pengobatan Ibu Hamil dalam Persepsi Budaya Suku Muna Kabupaten Muna

Penelitian ini bertujuan untuk mengetahui pola makan dan pola pencarian pengobatan ibu hamildalam persepsi budaya Suku Muna Kabupaten Muna. Penelitian ini merupakan penelitiankualitatif dengan metode pendekatan eksploratif. Penelitian ini dilaksanakan di Kabupaten Muna.Teknik pengambilan sampel dengan menggunakan snowball sampling berdasarkan kriteria inklusipada informan. Hasil penelitian menunjukan bahwa makanan yang menjadi pantangan selamaproses kehamilan adalah mangga macan, nenas, nangka, papaya, buah asam, terong dan jantungpisang. Makanan yang dianjurkan selama proses kehamilan adalah ikan, kacang-kacangan,sayuran hijau, buah-buahan, air kelapa muda, pisang dan jambu merah. Setelah melahirkan tidakboleh makan garam, ikan basah, ikan asin, pepaya, kelor, ubi jalar, ikan pari, yang mengandungsantan, ikan hiu, terong dan kangkung selama 44 hari dan hanya dianjurkan ikan bakar, nasitanpa garam, sayur Bening tanpa garam. Tujuan ibu hamil melakukan pemeriksaan danpengobatan pada dukun yaitu faktor kepercayaan, untuk mendapatkan perawatan danpengobatan selama kehamilan, untuk mengontrol letak posisi bayi dan untuk mendapatkannasehat perawatan dalam kehamilan sedangkan tujuan ibu hamil melakukan pemeriksaan padatenaga kesehatan yaitu untuk memastikan kehamilan, mendapatkan perawatan karena adakeluhan dan mengalami gangguan kesehatan serta adanya posyandu yang dilakukan secara rutinsetiap bulan. Kesimpulan dalam penelitian ini yaitu nilai dan norma dalam sosial budayaberkaitan dengan kepercayaan tertentu terhadap makanan, baik makanan yang dianjurkanmaupun makanan yang dipantang selama kehamilan serta pencarian pengobatan baik dalammengobati sendiri, pengobatan tradisional maupun pengobatan professional. Disarankan kepadaibu hamil tentang kehamilan, pertumbuhan dan perkembangan janin dalam rahim, serta tandabahaya perlu diwaspadai dan tenaga kesehatan memberikan penyuluhan tentang jenis danmanfaat makanan bagi ibu hamil dan juga peranan pemerintah dan toko masyarakat untukmeyakinkan pada masyarakat akan pentingnya makanan yang bergizi untuk memelihara kondisikesehatan ibu hamil

Dynamics of allosteric transitions in GroEL

The chaperonin GroEL-GroES, a machine which helps some proteins to fold, cycles through a number of allosteric states, the $T$ state, with high affinity for substrate proteins (SPs), the ATP-bound $R$ state, and the $R^{\prime\prime}$ ($GroEL-ADP-GroES$) complex. Structures are known for each of these states. Here, we use a self-organized polymer (SOP) model for the GroEL allosteric states and a general structure-based technique to simulate the dynamics of allosteric transitions in two subunits of GroEL and the heptamer. The $T \to R$ transition, in which the apical domains undergo counter-clockwise motion, is mediated by a multiple salt-bridge switch mechanism, in which a series of salt-bridges break and form. The initial event in the $R \to R^{\prime\prime}$ transition, during which GroEL rotates clockwise, involves a spectacular outside-in movement of helices K and L that results in K80-D359 salt-bridge formation. In both the transitions there is considerable heterogeneity in the transition pathways. The transition state ensembles (TSEs) connecting the $T$, $R$, and $R^{\prime\prime}$ states are broad with the the TSE for the $T \to R$ transition being more plastic than the $R\to R^{\prime\prime}$ TSE. The results suggest that GroEL functions as a force-transmitting device in which forces of about (5-30) pN may act on the SP during the reaction cycle.Comment: 32 pages, 10 figures (Longer version than the one published