Budding and vesiculation induced by conical membrane inclusions

Conical inclusions in a lipid bilayer generate an overall spontaneous curvature of the membrane that depends on concentration and geometry of the inclusions. Examples are integral and attached membrane proteins, viruses, and lipid domains. We propose an analytical model to study budding and vesiculation of the lipid bilayer membrane, which is based on the membrane bending energy and the translational entropy of the inclusions. If the inclusions are placed on a membrane with similar curvature radius, their repulsive membrane-mediated interaction is screened. Therefore, for high inclusion density the inclusions aggregate, induce bud formation, and finally vesiculation. Already with the bending energy alone our model allows the prediction of bud radii. However, in case the inclusions induce a single large vesicle to split into two smaller vesicles, bending energy alone predicts that the smaller vesicles have different sizes whereas the translational entropy favors the formation of equal-sized vesicles. Our results agree well with those of recent computer simulations.Comment: 11 pages, 12 figure

STUDENTS’ PERCEPTION AND THEIR ATTITUDE TOWARDS ENGLISH TEACHERS’ PERSONALITY

This research aimed at finding out the types of English teacherpersonality based on students’ perception and how is their attitudetoward their English teacher personality. This research used descriptivequalitative method. The subject of the research were students of secondgrades at SMKN 1 Palopo and there were 4 teachers of English atSMKN 1 as focus of this research. The researcher used snowballsampling technique in taking 12 students as the respondents of thisresearch. The instrument of this research was interview. The result ofthis research shows that (a) in the eyes of the students, there were 3 English teachers who have good personality, they were warm, caring to students, sociable, knowledgeable, creative, cheerful, close to students, and explicit. Then, 1 teacher has bad personality, such as low motivation, boring, lazy and apathetic. (b) the students’ attitude toward their English teacher is determined by teacher personality. If the teacher has good personality, students’ attitude is positive. On the contrary, if the teacher has bad personality, students’ attitude is negative. In the view of students, a good teacher should be kind, humorist, good motivator, knowledgeable, creative, explicit, close to students and sociable. Then, most of the students perceive that the teacher personality influence their mood in learning English.Keywords: perception, attitude, teacher personalit

PENGEMBANGAN MODUL IPA BERBASIS PENDEKATAN SAINTIFIK MATERI SISTEM PERNAPASAN MANUSIA UNTUK KELAS V SD

Penelitian dan pengembangan ini bertujuan untuk menghasilkan sebuah produk berupa bahan ajar IPA berbasis pendekatan saintifik untuk kelas V Sekolah Dasar dengan judul “Modul IPA berbasis Pendekatan Saintifik Materi Sistem Pernapasan Kelas V Sekolah Dasar”. Penelitian ini menggunakan metode penelitian pengembangan dikenal juga Research and Development (R & D) yang mengacu pada model pengembangan Borg and Gall. Penelitian ini dilaksanakan di SDN Menteng Atas 02 Pagi Jakarta Selatan yang melibatkan siswa kelas V A sebanyak 26 peseta didik dan V B sebanyak 13 peserta didik. Penelitian ini menggunakan metode kuesioner, oservasi, dan wawancara. Penelitian dilaksanakan dalam empat tahap yaitu, uji ahli, evaluasi one to one, evaluasi small group, dan evaluasi field test. Hasil penilaian uji coba ahli media sebesar 100%, ahli materi sebesar 86%, dan ahli bahasa sebesar 95%. Hasil Penilaian evaluasi small group sebesar 95,5 % dan evaluasi field test sebesar 97,5%. Berdasarkan hasil penilaian secara keseluruhan Pengembangan Modul IPA Berbasis Pendekatan Saintifik masuk dalam kategori sangat baik

Activated K-Ras and H-Ras display different interactions with saturable nonraft sites at the surface of live cells

Ras–membrane interactions play important roles in signaling and oncogenesis. H-Ras and K-Ras have nonidentical membrane anchoring moieties that can direct them to different membrane compartments. Ras–lipid raft interactions were reported, but recent studies suggest that activated K-Ras and H-Ras are not raft resident. However, specific interactions of activated Ras proteins with nonraft sites, which may underlie functional differences and phenotypic variation between different Ras isoforms, are unexplored. Here we used lateral mobility studies by FRAP to investigate the membrane interactions of green fluorescent protein–tagged H- and K-Ras in live cells. All Ras isoforms displayed stable membrane association, moving by lateral diffusion and not by exchange with a cytoplasmic pool. The lateral diffusion rates of constitutively active K- and H-Ras increased with their expression levels in a saturable manner, suggesting dynamic association with saturable sites or domains. These sites are distinct from lipid rafts, as the activated Ras mutants are not raft resident. Moreover, they appear to be different for H- and K-Ras. However, wild-type H-Ras, the only isoform preferentially localized in rafts, displayed cholesterol-sensitive interactions with rafts that were independent of its expression level. Our findings provide a mechanism for selective signaling by different Ras isoforms

Studi Perubahan Garis Pantai di Perairan Muara Sungai Kaliboyo, Batang

Perairan Muara Sungai Kaliboyo kawasan yang dinamis dan cepat mengalami perubahan garis pantai dan terbentuk spit di mulut sungai. Sedimen di daerah tersebut sering menutup muara sungai, sehingga mengganggu alur layar nelayan. Tujuan dari penelitian ini adalah untuk mengetahui indikasi perubahan garis pantai serta hubungan antara perubahan garis pantai dengan arus sejajar pantai di lokasi penelitian. Metode penelitian menggunakan metode deskriptif, untuk pengambilan sampel menggunakan metode purposive sampling, metode SMB untuk peramalan gelombang dan perhitungan menggunakan rumus empiris untuk validasi pasang surut, arus sejajar pantai dan parameter akresi-erosi.  Hasil penelitian menunjukkan Perairan Muara Sungai Kaliboyo mengalami akresi, hal ini dapat diketahui dari nilai parameter akresi-erosi di tiga penampang. Penampang 1 dengan nilai Go sebesar 0,62, penampang 2 dengan nilai Go sebesar 0,39 dan penampang 3 dengan nilai Go sebesar 0,56. Nilai Go di atas 0,111 menunjukkan adanya akresi. Gelombang datang dari arah Timur Laut menuju Barat Daya menimbulkan gelombang pecah dengan tinggi 0,28 meter pada kedalaman 0,90 meter sehingga membentuk sudut gelombang pecah (αb) sebesar 9,51°. Gelombang pecah tersebut menimbulkan arus sejajar pantai dari Timur ke Barat dengan kecepatan 0,42 m/dt yang mengangkut sedimen sejajar pantai, sehingga membentuk spit di muara sungai dari arah Timur memanjang ke Barat. Kata kunci : Sungai Kaliboyo, Perubahan Garis Pantai, Arus Sejajar Pantai   Kaliboyo River Estuary is a dynamic and rapidly changing area of the coastline and spits are formed at the river mouth. Sediment in this area often closes river mouths, disrupting the flow of fishermen's screens and clogging up river flow which sometimes causes floods around the river mouth. The purpose of this study is to find out indications of shoreline changes and the relationship between shoreline changes with longshore currents at the study site. The research method uses descriptive method, for sampling using purposive sampling method, SMB method for wave forecasting and calculations using empirical formulas. The research method uses descriptive method, for sampling using purposive sampling method, SMB method for wave forecasting and calculations using empirical formulas for tide validation, longshore currents and erosion-accretion parameters. The results showed that Kaliboyo River Estuary had accretion, this can be seen from the value of the erosion-accretion parameter in three cross sections. The first cross section with a Go value of 0,62, second cross section with a Go value of 0,39 and third cross section with a Go value of 0,56. Go values above 0,111 indicate accretion. Waves coming from the Northeast to the Southwest cause a breaking wave with a height of 0,28 meters at 0,90 meters depth to form an angle of breaking wave (αb) of 9.51°. The breaking wave caused a longshore current from East to West with a speed of 0,42 m /sec which transported sediment along the coast, thus forming a spit at the river mouth from the east extending to the west. Keywords : Kaliboyo River, Shoreline Change, Longshore Curren

Light and Electron Microscopical Studies on the Hyalocytes of Turkey (Meleagris Gallopavo)

The present study aimed to investigate the light and electron microscopical structure of the hyalocytes in turkey. This study was applied on a total number of 15 (10 males and 5 females) clinically healthy turkeys of Bronze black species, collected from a local farm in Assiut Governorate, Egypt. For sampling and fixation, 30 turkey's eyeballs were enucleated and subjected to study. The hyalocytes appeared as large cell with different shapes (rounded, oval or elliptical). They located within ambushes found along the outer surface of the retino-pecteneal membrane. In these cells, present numerous cytoplasmic vacuoles and large oval nucleus located near the internal part of the cell. There were many cytoplasmic processes that joined each other as a fine meshwork enclosing several vesicles or parts of foreign materials along the external portion of the cell. On the internal or deep surface of the cell present numerous filopodia, which extended to occupy the depressions found on the outer surface of the retino-pecteneal membrane. The presence of ingested foreign materials and the appearance of filopodia in a moving condition along the internal surface of the cell insure that hyalocytes are considered highly active phagocytic cells