Complex intron generation in the yeast genus Lipomyces

In primary transcripts of eukaryotic nuclear genes, coding sequences are often interrupted by U2-type introns. Such intervening sequences can constitute complex introns excised by consecutive splicing reactions. The origin of spliceosomal introns is a vexing problem. Sequence variation existent across fungal taxa provides means to study their structure and evolution. In one class of complex introns called [D] stwintrons, an (internal) U2 intron is nested within the 5'-donor element of another (external) U2 intron. In the gene for a reticulon-like protein in species of the ascomycete yeast genus Lipomyces, the most 5' terminal intron position is occupied by one of three complex intervening sequences consistent of differently nested U2 intron units, as demonstrated in L. lipofer, L. suomiensis, and L. starkeyi. In L. starkeyi, the donor elements of the constituent introns are abutting and the complex intervening sequence can be excised alternatively either with one standard splicing reaction or, as a [D] stwintron, by two consecutive reactions. Our work suggests how [D] stwintrons could emerge by the appearance of new functional splice sites within an extant intron. The stepwise stwintronisation mechanism may involve duplication of the functional intron donor element of the ancestor intron.

Analisis kemampuan pemecahan masalah siswa dalam menyelesaikan soal cerita barisan ditinjau dari adversity quotient

Tujuan dari penelitian kualitatif ini adalah untuk mendeskripsikan kemampuan pemecahan masalah siswa dalam menyelesaikan soal cerita pada materi barisan ditinjau dari Adversity Quotient (AQ). Kemampuan pemecahan masalah memiliki 4 indikator yaitu: 1) mengidentifikasi masalah, 2) merumuskan masalah, 3) melaksanakan strategi, dan 4) memverifikasi solusi. Penelitian dilaksanakan pada semester genap tahun ajaran 2018/2019. Subjek penelitian terdiri dari 30 Siswa kelas XI IPA 1 SMA Kesatrian 1 Semarang yang telah diajarkan materi barisan. Kemudian dipilih subjek berdasarkan tipe AQ yaitu Climber, Camper dan Quitter. Teknik pengumpulan data menggunakan angket AQ, tes kemampuan pemecahan masalah, dan wawancara. Teknik analisis data penelitian ini meliputi reduksi data, penyajian data, dan penarikan kesimpulan/verifikasi. Hasil penelitian menunjukkan bahwa siswa bertipe Climber mampu memenuhi seluruh indikator dari 4 indikator kemampuan pemecahan masalah yaitu indikator 1, 2, 3, dan 4. Siswa bertipe Camper mampu memenuhi 3 dari 4 indikator kemampuan pemecahan masalah yaitu indikator 1, 2, dan 3. Siswa bertipe Quitter hanya mampu memenuhi 1 indikator kemampuan pemecahan masalah yaitu indikator 2. Analysis of students' problem-solving abilities in solving word problem sequence in terms of adversity quotientAbstractThe purpose of this qualitative research was to describe the students' problem-solving abilities in solving word problems in the sequences material in terms of Adversity Quotient (AQ). Problem-solving has four indicators namely: 1) overcoming the problem, 2) formulating the problem, 3) implementing the strategy, and 4) verifying the solution. The study was conducted in the even semester of the 2018/2019 academic year. The research subjects consisted of 30 students of class XI IPA 1 of Kesatrian 1 Semarang High School who had taught the sequences material. Then the subject was chosen based on the type of AQ namely climber, camper and quitter. Data collection techniques using the AQ questionnaire, the problem-solving test, and interview. The data analysis techniques of this study include data reduction, data presentation, and conclusion. The results showed that students of the climber type were able to meet all the indicators of the four indicators of problem-solving namely indicators 1, 2, 3, and 4. Students of the camper type were able to fulfill three from four indicators of problem-solving namely indicators 1, 2, and 3. Students' quitter type were only able to meet one indicator of problem-solving, namely indicator 2.

On the Construction of a Problem Sequence

This article is a complementary article to three earlier published articles (Burman & Wallin, 2014; Burman, 2014; Burman, 2016) about the use of problem sequences in mathematics instruction in the grades seven to nine in Finland. The pupils work with problems using the same strategy in different contexts, or with only one problem where they gradually proceed towards the solution. In both cases, the problems are solved in steps under the guidance of the teacher. The article focuses on the considerations designer of a problem sequence has, as the design of the sequence is accomplished. In general, the pupils are supposed to be provided with the possibility to think creatively, to work mostly in groups but also individually, and to be inspired by tasks related to real-world situations.

DEPOSITIONAL SYSTEMS AND SEQUENCE STRATIGRAPHY OF THE CRETACEOUS WARNBRO GROUP, VLAMING SUB-BASIN, WESTERN AUSTRALIA

Petroleum exploration of the Vlaming Sub-basin (offshore Perth Basin) has to date primarily focussed on targets sealed by the shale facies of the Early Cretaceous Warnbro Group, a predominantly marine succession. The Warnbro Group is formally sub-divided into the Gage Sandstone Member (base), South Perth Shale and Leederville Formation (top). However, owing to diachroneity between lithofacies, adherence to the formal nomenclature has rendered the prediction of shale facies at specific locations unreliable, resulting in a number of invalid exploration tests.To resolve this problem, sequence and seismic stratigraphic concepts have been used within exploration permit WA-221-P to provide a framework for a new stratigraphic model for the Warnbro Group. Seven depositional sequences have been identified.The model recognises that palaeogeography during Warnbro Group deposition was largely governed by tectonism associated with the Neocomian break-up event which produced a complex assemblage of fluvio-deltaic, shelfal and submarine fan systems. Sequence boundary development can be related to phases of tectonism following the Neocomian break-up as well as to eustatic fluctuations, while variations in base-level, subsidence rate, sediment supply, basin physiography and a basinwide marine transgression primarily control the environments of deposition and their spatial distribution.The model has enabled the lithofacies of the Warnbro Group to be assigned to a predictable succession of associated systems tracts, providing a practical approach to understanding the distribution and geometries of Warnbro Group reservoir and seal facies within the Vlaming Sub-basin.